Water dispersible hot melt adhesives and uses thereof

Abstract

The present disclosure relates to water dispersible, low application temperature, hot melt adhesives comprising a sulfopolyester, a plasticizer, and a tackifier. The adhesives exhibit extended open time and high tack strengths and are useful in a wide variety of applications including the preparation of paper articles and other products that can be recycled.

Description

Attorney Docket No.: 2024PF00172WO-shlWATER DISPERSIBLE HOT MELT ADHESIVES AND USES THEREOFFILED OF THE INVENTION

[0001] The present invention relates to water dispersible, low application temperature, hot melt adhesives comprising, in certain embodiments, a sulfopolyester, a plasticizer (such as polyethylene glycol) and a tackifier (such as an optionally modified rosin ester). The adhesives exhibit extended open time and high tack strengths and are useful in a wide variety of applications including the preparation of paper articles and other products that can be recycled.BACKGROUND OF THE INVENTION

[0002] In a paper production process, sheet transfer is an important step where sheet from paper production is wound onto an empty spool. The process of changing a full reel of paper to an empty spool is called a turnup process. During the turnup, adhesive is used to connect paper from paper production onto an empty spool and start winding paper to produce a reel of paper for downstream paper operations. During the downstream operation, the full reel of paper is converted into smaller rolls and packaged for consumer use. See, e.g., U.S. Publication No. 2020 / 0039777.

[0003] Both water based adhesives and pressure sensitive adhesives are currently used during the turnup process. However, each class of adhesive suffers from significant drawbacks. The drawback for the water-based adhesive is splashing of adhesive and lack of tack strength during the turnup. While water-based adhesives have different viscosities that ranges from flowing like water (1 centipoise) up to viscosity greater than 20,000 cPs at room temperature, they lack cohesive strength even at viscosities greater than 20,000 cPs upon application, because it requires time to evaporate the water in the adhesive to build cohesive strength. This results in splashing and slinging (centrifugal force throws the water-based adhesive on equipment and surrounding areas due to improper viscosity and roller speeds), and housekeeping issues (requires cleaning roller and other components of the equipment) during the turnup.

[0004] While pressure sensitive adhesives do not cause splashing during the turnup, and the adhesive provides the strength to allow paper to latch onto the empty spool, the amorphic and hydrophobic nature of the pressure sensitive adhesive results in difficulties in recycling process.Attorney Docket No.: 2024PF00172WO-shlThe inability to effectively remove these synthetic contaminants stands as a barrier to the increased recycling of paper waste.

[0005] U.S. Patent Nos. 5,098,962 and 6,162,890 and European Patent No. EP 1,268,701 describe water dispersible hot melt adhesive compositions.

[0006] There is still, however, a need for new hot melt adhesives that not only exhibit good open time and tack strength but are also water dispersible and therefore environmentally friendly. The present invention addresses these needs and results in low application temperature, hot melt adhesives that allow for recycling of unconverted paper during a turnup process without splashing and without contamination from sticky adhesive residue.SUMMARY OF THE INVENTION

[0007] The present inventors have surprisingly developed hot melt adhesives that not only exhibit good open time and tack strength but are also water dispersible and therefore environmentally friendly during, e.g., a turnup process in paper production. As the adhesives described herein are dispersible in water, during the paper recycling process, recyclable paper fiber can be used to make new paper again in the paper production process without the contamination of the residual sticky adhesive. In addition, the hot melt adhesives described herein provide sufficient adhesive strength even after long open time for the paper turnup process.

[0008] The invention was able to solve the challenges presented by the use of water based adhesive or pressure sensitive adhesive by increasing the viscosity of the adhesive to minimize splashing and providing sufficient adhesive strength similar to that of a pressure sensitive adhesive with a long open time characteristic of both the water based adhesive and pressure sensitive adhesive while offering water dispersibility characteristics to the performance of the adhesive to significantly reduce waste and improve the recyclability of the unconvertible paper generated during the manufacturing process.

[0009] The hot melt adhesives described herein may be used in paper turnup processes, and in tissue and towel applications, such as, for example, core winding, lamination, tissue pick-up and tail sealing, and in paper bag applications.Attorney Docket No.: 2024PF00172WO-shl

[0010] In one aspect, the present invention relates to a water dispersible hot melt adhesive comprising:(a) a water dispersible polymer (e.g., a sulfopolyester);(b) a tackifier (e g., an optionally, modified resin based tackifier);(c) a plasticizer; and(d) optionally, an antioxidant; wherein the hot melt adhesive:(i) has an open time of at least about 4 weeks, wherein the initial loop tack value is between about 3 and about 15 ounce force per 0.125 inch2and remains in said range for up to about 3 weeks, when measured in accordance with ASTM D6195-03;(ii) has a water dispersibility of greater than about 80% (such as greater than about 90% or greater than about 95%), when measured in accordance with TAPPI UM666; or(iii) both (i) and (ii).In one embodiment of any of the hot melt adhesives described herein, the hot melt adhesive:(i) has an open time of at least about 1 week; wherein the initial tack value is between about 3 and about 15 ounce force per 0.125 inch2and remains in said range for up to about 1 week, when measured in accordance with ASTM D6195-03; and(iii) has a water dispersibility of greater than about 80% (such as greater than about 90% or greater than about 95%), when measured in accordance with TAPPI UM666.

[0011] In certain embodiments of any of the hot melt adhesives described herein, the water dispersible polymer (such as a sulfpolyester) hasAttorney Docket No.: 2024PF00172WO-shl(i) a glass transition temperature (Tg) of between about -20° C and about 65° C, such as between about 0° C and about 52° C;(ii) a melt viscosity of between about 1000 and about 150,000 cPs, such as between about 5,000 and about 50,000 cPs (e.g., measured at 177° C); or(iii) both (i) and (ii).

[0012] In certain embodiments of any of the hot melt adhesives described herein, the tackifier comprises a polar tackifier, such as, for example, a rosin, a rosin ester, a modified rosin ester, a styrenated terpene resin, a phenolic terpene resin, or any combination of any of the foregoing.

[0013] In certain embodiments of any of the hot melt adhesives described herein, the tackifier comprises an optionally modified rosin ester. The modification process may include blending, grafting and curing. Blending is commonly described as the process of mixing two or more rosin esters together without producing a chemical reaction. Grafting is a process where functional groups are reacted with the backbone of rosin esters via Diels- Alder reaction, as described in, for example, Tirto Prakoso et al., 2021 IOP Conf. Ser.: Mater. Sci. Eng., 1143, 012071. Curing provides a crosslinked network with functional groups in the network. Modified rosin esters, by means of blending and grafting, are particularly preferred tackifiers.

[0014] In certain embodiments of any of the hot melt adhesives described herein, the tackifier comprises a modified rosin ester.

[0015] In certain embodiments of any of the hot melt adhesives described herein, the tackifier comprises a modified rosin ester, wherein the rosin ester is modified with maleic anhydride, glycidyl methacrylate, butyl acrylate, methyl methacrylate, propenoic acid, vinyltrimethoxysilane, or any combination of any of the foregoing.

[0016] In certain embodiments of any of the hot melt adhesives described herein, the tackifier comprises a maleic anhydride modified rosin ester.

[0017] In certain embodiments of any of the hot melt adhesives described herein, the tackifier comprises a styrenated terpene resin, a phenolic terpene resin, or any combination thereof.Attorney Docket No.: 2024PF00172WO-shl

[0018] In certain embodiments of any of the hot melt adhesives described herein, the tackifier has:(i) an acid value of between about 5 and about 100, such as between about 10 and about 80;(ii) a softening point of between about 0° C and about 150° C, such as between about 50° C and about 140° C; or(iii) both (i) and (ii).

[0019] In certain embodiments of any of the hot melt adhesives described herein, the plasticizer comprises polyalkylene glycols such as polyethene glycol, polypropylene glycol, polybutylene glycol, an ester (such as, but not limited to sebacates, adipates, terephthalates, dibenzoates, glutarates, phthalates, and azelates, or a combination of any of the foregoing) so long as they are compatible with the other components in the hot melt adhesive. Compatibility refers to the ability to remain in a homogeneous solution without phase separation in both room temperature and at elevated temperatures.

[0020] In certain embodiments of any of the hot melt adhesives described herein, the plasticizer comprises polyethylene glycol.

[0021] In certain embodiments of any of the hot melt adhesives described herein, the plasticizer (such as polyethylene glycol) has a molecular weight of between about 100 and about 10,000, such as between about 300 and about 3000, or between about 300 and about 1800 Daltons.

[0022] In certain embodiments of any of the hot melt adhesives described herein, the plasticizer (such as polyethylene glycol) has a molecular weight of about 600. In certain embodiments of any of the hot melt adhesives described herein, the plasticizer (such as polyethylene glycol) has a molecular weight of about 1450.

[0023] In certain embodiments of any of the hot melt adhesives described herein, the adhesive comprises:Attorney Docket No.: 2024PF00172WO-shl(i) between about 5 % w / w and about 90 % w / w, such as between about 30 % w / w and about 80 % w / w, between about 45 % w / w and about 75 % w / w of a water dispersible polymer (such as a sulfopolyester);(ii) between about 5 % w / w and about 90 % w / w, such as between about 10 % w / w and about 50 % w / w. between about 15 % w / w and about 30 % w / w of a plasticizer (such as polyethylene glycol);(iii) between about 3 % w / w and about 90 % w / w, such as between about 5 % w / w and about 30 % w / w, between about 10 % w / w and about 15 % w / w of a tackifier (such as an optionally modified rosin ester); or(iv) any combination of (i), (ii) and (iii).In certain embodiments of any of the hot melt adhesives described herein:(i) the water dispersible polymer comprises a sulfopolyester;(ii) the plasticizer comprises polyethylene glycol;(iii) the tackifier comprises an optionally modified rosin ester; or(iv) any combination of (i), (ii) and (iii).

[0024] In certain embodiments, any of the hot melt adhesives described herein has an open time of at least about one hour, such as at least about 1 day, at least about 2 days, at least about 3 days, at least about 4 days, at least about 5 days, at least about 6 days, at least about 7 days, at least about 14 days or at least about 21 days. The open time is the time after an adhesive is applied during which a serviceable bond can be made, and this was correlated by measuring loop tack test. The initial loop tack measurements were evaluated for the hot melt adhesive and then taken daily, and when they remained in the acceptable range, they were considered to have open time for that duration. It is desirable to have a long open time for a hot melt adhesive.

[0025] In additional embodiments, any of the hot melt adhesives described herein has an open time of at least about 7 days, such as at least about 8 days, at least about 9 days, at least about 10Attorney Docket No.: 2024PF00172WO-shl days, at least about 11 days, at least about 12 days, at least about 13 days, at least about 14 days or at least about 21 days.

[0026] In additional embodiments, any of the hot melt adhesives described herein has a loop tack value of between about 3 and about 15, such as between about 4 and about 7 ounce force per 0.125 in2, when measured, for example, in accordance with ASTM D6195-03.

[0027] In additional embodiments, any of the hot melt adhesives described herein has a loop tack value of greater than about 3, such as greater than about 4 or greater than about 5 ounce force per 0.125 in2, when measured, for example, in accordance with ASTM D6195-03.

[0028] In additional embodiments, any of the hot melt adhesives described herein has a loop tack value of less than about 15, such as less than about 12 or less than about 10 ounce force per 0.125 in2, when measured, for example, in accordance with ASTM D6195-03.

[0029] In additional embodiments, any of the hot melt adhesives described herein has a loop tack value of greater than about 3, such as greater than about 4, and less than about 15, such as less than about 12 or less than about 11 ounce force per 0.125 in2, when measured, for example, in accordance with ASTM D6195-03.

[0030] In additional embodiments, any of the hot melt adhesives described herein has a loop tack value of less than about 15, such as less than about 12 or less than about 11 ounce force per 0.125 in2, when measured, for example, in accordance with ASTM D6195-03.

[0031] In certain embodiments, any of the hot melt adhesives described herein has a water dispersibility of greater than about 80%, such as greater than about 81%, greater than about 82%, greater than about 83%, greater than about 84%, greater than about 85%, greater than about 86%, greater than about 87%, greater than about 88%, greater than about 89%, greater than about 90%, greater than about 91%, greater than about 92%, greater than about 93%, greater than about 94%, greater than about 95%, greater than about 96%, greater than about 97%, greater than about98%, or greater than about 99%, when measured, for example, in accordance with TAPPI UM666.Attorney Docket No.: 2024PF00172WO-shl

[0032] In additional embodiments, any of the hot melt adhesives described herein has a viscosity of between about 1,000 cPs and about 20,000 cPs, such as between about 1,500 cPs and about 18,000 cPs or between about 2,000 cPs and about 15,000 cPs when measured at 250°F, for example, in accordance with ASTM D3236.

[0033] In one embodiment of any of the hot melt adhesives described herein, the hot melt adhesive exhibits no phase separation (e.g., remains homogeneous) when stored, e.g., for 2 days in a convection oven set at 320° F.

[0034] In certain embodiments, any of the hot melt adhesives described herein can be applied on to a substrate by means of spraying (e.g., nozzle spraying), brushing, gravity flowing, printing (e.g., screen printing), roll coating, and other means known in the art.

[0035] In another aspect, the present invention relates to an article of manufacture comprising a hot melt adhesive according to any of the embodiments described herein.

[0036] In certain embodiments, the article of manufacture is a bag, a tissue, a paper towel, a kitchen towel, toilet paper, an industrial towel, a note pad, a sticky (POST IT®) note, or a tape.BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 shows Formulations 21 and 22 of Example 8 initially at 320° F (FIGS. 1 A and IB, respectively) and after standing for 48 hours at 320° F (FIGS 2A and 2B, respectively).DETAILED DESCRIPTION OF THE INVENTION

[0038] As used herein, the term “open time” refers to the time an adhesive, after it is dispensed onto a substrate, is left open before a second substrate is placed onto the adhesive and is still able to form a bond between the two substrates.

[0039] As used herein, the term “about” when referring to a number or a numerical range means that the number or numerical range referred to is an approximation within experimental variability (or within statistical experimental error), and thus the number or numerical range may vary from, for example, between 1% and 15% of the stated number or numerical range.Attorney Docket No.: 2024PF00172WO-shl

[0040] As used herein, the term “comprising” (and related terms such as “comprise” or “comprises” or “having” or “including”) includes, but is not limited to, those embodiments, for example, an embodiment of any composition of matter, composition, method, or process, or the like, that “consist of’ or “consist essentially of’ the described features.

[0041] As used herein, the terms “paper towel” and “paper towel substrate” in one embodiment refer to a commercially available, absorbent, disposable household towel made from wood pulp and primarily used in the home for cleaning.

[0042] All ranges disclosed herein are inclusive of the recited endpoint and independently combinable (for example, the range of "from 2 to 10" is inclusive of the endpoints, 2 and 10, and all the intermediate values). The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value; they are sufficiently imprecise to include values approximating these ranges and / or values. As used herein, approximating language may be applied to modify any quantitative representation that may vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about," may not be limited to the precise value specified, in some cases. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. The modifier "about" should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression "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 number. For example, "about 10%" may indicate a range of 9% to 11 ", and "about 1" may mean from 0.9-1.1. Other meanings of "about" may be apparent from the context, such as rounding off, so, for example "about 1" may also mean from 0.5 to 1.4.The Water Dispersible Polymer

[0043] In certain embodiments of any of the hot melt adhesives described herein, the water dispersible polymer is a sulfopolyester. Suitable sulfopolyesters for use in the hot melt adhesives described herein are described in, for example, U.S. Patent Nos. 5,859,152 and 6,007,910 and in U.S. Publication No. 2006 / 0058438, each of which is hereby incorporated by reference in its entirety.Attorney Docket No.: 2024PF00172WO-shlThe Plasticizer

[0044] Suitable plasticizers must be compatible with other components in the hot melt adhesive, and include monohydric or polyhydric alcohols, such as glycol monophenyl ether, hexamethylene glycol, glycerol and, in particular, polyalkylene glycols Polyethylene glycols and esterified or etherified derivatives thereof are preferred. Polypropylene glycol, polybutylene glycol and polymethylene glycol are also suitable.The Tackifier

[0045] Rosins are natural tackifiers derived from pine tree by-products such as gum rosin, wood rosin and tall oil rosin with an acid number up to 170. Rosin esters are derived from the esterification of the rosins using various alcohols, such as, for example, glycerol, methanol, tri- ethylene-glycol and pentaerythritol. Styrenated terpene and terpene phenolic are polar resins due to the presence of aromatic styrene and phenolic hydroxyl groups, respectively.

[0046] In certain embodiments, useful tackifying resins for use in any of the water dispersible holt melt adhesives described herein include any compatible resins or mixtures thereof such as (1) natural and modified rosins such, for example, as gum rosin, wood rosin, tall oil rosin, distilled rosin, hydrogenated rosin, dimerized rosin, and polymerized rosin; (2) rosin esters such as glycerol and pentaerythritol esters of natural and modified rosins, such, for example as the glycerol ester of pale, wood rosin, the glycerol ester of hydrogenated rosin, the glycerol ester of polymerized rosin, the pentaerythritol ester of hydrogenated rosin, and the phenolic-modified pentaerythritol ester of rosin; and (3) phenolic modified (a) terpene or (b) a-methyl styrene resins as well as the hydrogenated derivatives thereof such, for example, as the resin product resulting from the condensation, in an acidic medium of a bicyclic terpene and a phenol. Mixtures of two or more of the above described tackifying resins, as well as blends of the above resins with small amounts of (e.g., less than about 20% of the adhesive) less compatible resins may be utilized for some formulations.

[0047] Non limiting representative polar tackifiers include also ionic materials such as FORAL NC available from Hercules; non-ionic materials such as FORAL AX also from Hercules; alpha methyl styrene phenolics such as URATAK 68520 from DSM Resins; rosin esters such asAttomey Docket No.: 2024PF00172WO-shlUNITAC R100L available from Union Camp; and terpene phenolics such as NIREZ 300, available from Arizona Chemical.

[0048] In certain embodiments of any of the hot melt adhesives described herein, the tackifier comprises a modified rosin ester, wherein the rosin ester is modified with maleic anhydride, fumaric anhydride, glycidyl methacrylate, butyl acrylate, methyl methacrylate, propenoic acid, vinyltrimethoxysilane, or any combination of any of the foregoing. In certain embodiments of any of the hot melt adhesives described herein, the tackifier comprises a maleic anhydride modified rosin ester. In certain embodiments of any of the hot melt adhesives described herein, the tackifier comprises a fumaric anhydride modified rosin ester.

[0049] Non limiting representative modified rosin ester tackifiers include Teckros M105, Teckros 120, Teckros AF128, Teckros AF160 from Teckrez.

[0050] In certain embodiments of any of the hot melt adhesives described herein, the tackifier comprises a styrenated terpene resin, a phenolic terpene resin, or any combination thereof.Antioxidants

[0051] Among the applicable stabilizers or antioxidants included herein are high molecular weight hindered phenols and multifunctional phenols, such as sulfur and phosphorous-containing phenol. Hindered phenols are well known to those skilled in the art and may be characterized as phenolic compounds which also contain sterically bulky radicals in close proximity to the phenolic hydroxyl group thereof. In particular, tertiary butyl groups generally are substituted onto the benzene ring in at least one of the ortho positions relative to the phenolic hydroxyl group. The presence of these sterically bulky substituted radicals in the vicinity of the hydroxyl group serves to retard its stretching frequency, and correspondingly, its reactivity; this hindrance thus providing the phenolic compound with its stabilizing properties. Representative hindered phenols include, for example, l,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)- benzene; pentaerythrityl tetrakis-3(3,5-d i-tert-butyl-4-hydroxyphenyl)-propionate; n-octadecyl- 3(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate; 4,4'-methylenebis(2,6-tert-butyl-phenol); 4,4'- thiobis(6-tert-butyl-o-cresol); 2, 6-di -tertbutylphenol; 6-(4-hydroxyphenoxy)-2,4-bis(n-octyl-Attorney Docket No.: 2024PF00172WO-shl thio)- 1 ,3,5 triazine; di-n-octylthio)ethyl 3,5-di-tert-butyl-4-hydroxy-benzoate; and sorbitol hexa[3 -(3, 5-di -tert -butyl-4-hydroxy-phenyl)-propi onate],

[0052] Such antioxidants are commercially available from Ciba Specialty Chemicals and include IRGANOX® 565, 1010, 1076 and 1726 which are hindered phenols. These are primary antioxidants which act as radical scavengers and may be used alone or in combination with other antioxidants such as phosphite antioxidants like IRGAFOS® 168 available from Ciba Specialty Chemicals. Phosphite antioxidants are considered as secondary antioxidants, and are not generally used alone. These are primarily used as peroxide decomposers. Other available antioxidants are CYANOX® LTDP available from Cytec Industries and ETHANOX® 330 available from Albemarle Corp. Many such antioxidants are available either to be used alone or in combination with other such antioxidants. These compounds are added to the hot melts in small amounts, typically less than about 10 wt. %, and have no effect on other physical properties.Additional Additives

[0053] The adhesive compositions described herein may optionally include additional additives. The optional additional additives may be present in the composition at a weight percent from greater than zero, about 0.1 percent, about 0.5 percent, or about one percent, to about five percent, about 10, about 20 percent, or about 30 percent, based on the total weight of the composition, or a weight percentage between any pair of the foregoing values. The weight percentage of the optional additional additives may be applied to the combined total of all additional additives present or to each additional additive separately.

[0054] Some examples of additional additives include, but are not limited to, crosslinkers, chain extenders, humectants, thixotropy, nucleating agents, surfactants, diluents, anti-settling agents, flame-retardant enhancers, and any combination thereof. In some embodiments, the optional additional additives include waxes, release agents, reinforcing fillers, pigments, heat stabilizers, UV stabilizers, plasticizers, rheology modifiers, processing aids, lubricants, mold release agents, biocides, or component or combinations thereof. Suitable reinforcing fillers include mineral fillers and glass fibers.Attorney Docket No.: 2024PF00172WO-shl

[0055] Table 1 below shows exemplary, non-limiting, properties of some components of the hot melt adhesives described herein.TABLE 1ExamplesSystem Components

[0056] TECHNOMELT® PS 9625 RE (“PS 9625”) is a pressure sensitive hot melt available from Henkel Corp. (Bridgewater, NJ). AQUENCE® TACK 5157 (“TACK 5157”) is a water based adhesive available from Henkel Corp. (Bridgewater, NJ). Sulfopolyester with Tg 35-38°C is available from Eastman. Sulfopolyester with Tg 51-55°C is available from Eastman. Rosin ester with softening point of 85°C is available from Kraton. Rosin ester with softening point 100° C is available from Kraton. Maleic anhydride modified rosin ester with softening point of 105° C is available from Teckrez. Maleic anhydride modified rosin ester with softening point of 120° C is available from Teckrez. Terpene phenolic with softening point of 96° C is available fromAttorney Docket No.: 2024PF00172WO-shlKraton. Polyethylene glycol with molecular weight with 600 Daltons is available from Sigma Aldrich. Polyethylene glycol with molecular weight 1450 Dalton is available from Sigma Aldrich. Hindered phenolic and phosphite antioxidants are available from Everspring.Test MethodsTack Method 1

[0057] A bead of adhesive, about 0.125 inch wide, was applied at a specified application temperature onto a 3-inch wide kraft paper. The adhesive was left open for a specified time. A paper towel was pre-cut to 1-inch wide. The paper towel substrate was placed on top of the kraft paper and bonded by rolling a 2.2 kg roller onto the bond line. The paper towel was attached to a force gauge and the tack strength of the adhesive was immediately measured by the force gauge pulling manually onto the paper towel. The tack test was repeated 5 times per sample.Tack Method 2

[0058] A bead of adhesive, about 0.125 inch wide, was applied at a specified application temperature onto a 2-inch wide kraft paper. The adhesive was left open for a specified time. The paper towel was pre-cut to 2-inch wide. The kraft paper was placed on top of the paper towel substrate and bonded by rolling a 2.2 kg roller onto the bond line. The kraft paper was attached to a force gauge and the tack strength of the adhesive was immediately measured by the force gauge pulling manually onto the kraft paper. The tack test was repeated 5 times per sample.Loop Tack Test

[0059] Kraft paper was pre-cut into 1-inch by 5-inch strips. A bead of adhesive, about 0.125 inch wide, was applied at a specified temperature onto the kraft paper. The adhesive was left open for specified time. The specimen was bent back on itself with the adhesive facing outward to form a tear drop shape. The ends of the specimen were fastened with a 1-inch wide masking tape thereby forming a 3-inch tear drop loop. The tear shape loop was then inserted onto the loop tack tester by clamping the mask tape ends and allowing the 3-inch loop hanging freely from the clamp. The bottom panel was wrapped with paper towel substrate and the wrapped bottom panelAttorney Docket No.: 2024PF00172WO-shl was inserted into the panel guide. The loop tack strength was conducted according to ASTM D6195-03. The tack test was repeated 5 times per sample.Water Dispersibility Test

[0060] This water dispersibility test is adapted from TAPPI modified UM666 for hot melt adhesives. It is a hot melt repulpability test and performed as follows. 0.5 gram of the hot melt adhesive was weighed and allowed to cool. This is the “Initial Adhesive Weight”. The preweighed adhesive was placed in a Waring blender with 350 milliliters of water at 160°F. The blender was [was] run for 10 minutes at its highest speed of 13,900 RPM. The mixture was poured through a pre-weighed (“Initial Screen Weight”) 60 mesh screen. Any residual in the blender vessel was washed through the screen using additional water (room temperature). Then the screen was rinsed with clean room temperature water. The screen, with any residual adhesive on it, was dried in an oven set at 110° F overnight. The screen is then re- weighed (“Finally Screen Weight”). The % dispersibility may be calculated as follows:Final Adhesive Weight = Final Screen Weight - Initial Screen Weight% Dispersibility = ((Initial Adhesive Weight - Final Adhesive Weight) / Initial Adhesive Weight) x 100Viscosity measurement

[0061] Viscosity was measured with a Brookfield viscometer, spindle 27 at the application temperature (350, 320 or 250oF), in accordance with ASTM D3236.Preparation Process

[0062] The adhesive formulations were prepared as follows. All ingredients were weighed and added to a glass or metal container. The contents were heated to 350°F and mixed until homogeneous.Example 1Attorney Docket No.: 2024PF00172WO-shl

[0063] In this example, the tack strength of a hot melt adhesive as described herein (Formulation 1) was compared to that of a pressure sensitive adhesive (PS 9625) and a water-based adhesive (TACK 5157).

[0064] After 1 hour of open time, the tack strength of Formulation 1 was 10 times higher than that of TACK 5157.Example 2

[0065] In this example, the tack strength of a hot melt adhesive composition containing no tackifier (Formulation 2) and hot melt adhesive compositions as described herein (Formulations 3-5) containing different amounts of rosin ester tackifiers were compared with that of pressure sensitive adhesive PS 9625.Attorney Docket No.: 2024PF00172WO-shl

[0066] The tack strength after 1 hour of open time of Formulations 4 and 5 was higher than that of Formulation 1. The tack strength of Formulation 4 exceeded that of PS 9625.Example 3

[0067] In this example, the tack strength of hot melt adhesive compositions as described herein containing different rosin esters and combinations of sulfopolyesters in different amounts (Formulations 6-11) were compared with that of pressure sensitive adhesive PS 9625.Attorney Docket No.: 2024PF00172WO-shl

[0068] After 1 hour of open time, the tack strength of Formulations 6, 7, 8, 9, 10 and 11 was higher than that of Formulation 1. The tack strength of Formulations 6, 7, 8, 9, 10 and 11 also exceeded that of PS 9625.Example 4Attorney Docket No.: 2024PF00172WO-shl

[0069] In this example, the tack strength of hot melt adhesive compositions as described herein containing sulfopolyesters, polyethylene glycol and modified rosin esters in different amounts (Formulations 12-15) were compared with that of pressure sensitive adhesive PS 9625.Attorney Docket No.: 2024PF00172WO-shl

[0070] After one hour of open time, the tack strength of Formulations 12 and 14 were higher than that of PS 9625. The tack values of F12, F13, F14, and F15 are considered to be either comparable or higher than that of PS9625.Example 5

[0071] In this example, the tack strength of hot melt adhesive compositions as described herein containing polyethylene glycol with a molecular weight of 1450 (Formulations 16-19) were compared to that of pressure sensitive adhesive PS 9625.Attorney Docket No.: 2024PF00172WO-shl

[0072] After one hour of open time, the tack strength of Formulations 16, 17, 18 and 19 was higher than that of PS 9625.Example 6

[0073] The water dispersibility of hot melt compositions as described herein (Formulations 14 and 20) was measured according to the methods described herein.Attorney Docket No.: 2024PF00172WO-shl

[0074] Both formulations 14 and 20 exhibit a water dispersibility of 95% or greater.Example 7

[0075] The tack strength of a holt melt adhesive composition as described herein (Formulation 14) was measured via the loop tack test with increasing open time.

[0076] With open times up to 28 days, the tack strength of Formulation 14 was higher than that of pressure sensitive adhesive PS 9625.Example 8

[0077] The thermal stability of hot melt adhesive compositions as described herein (Formulations 21 and 22) was measured. Formulation 22 contains a maleic anhydride modified resin tackifier.Attorney Docket No.: 2024PF00172WO-shl

[0078] FIG. 1 shows Formulations 21 and 22 initially at 320° F (FIGS. 1A and IB, respectively) and after standing for 48 hours at 320° F (FIGS 2A and 2B, respectively). As can be seen, Formulation 21 exhibited some phase separation after standing for 48 hours at 320° F while Formulation 22 remained homogeneous.

[0079] All patents and publications cited herein are incorporated by reference in their entirety.

Claims

Attorney Docket No.: 2024PF00172WO-shlWHAT IS CLAIMED IS;1. A water dispersible hot melt adhesive comprising:(a) a sulfopolyester;(b) a rosin tackifier;(c) a plasticizer selected from polyethene glycol, an ester, and any combination thereof; and(d) optionally, an antioxidant wherein the hot melt adhesive:(i) has an open time of at least about 4 weeks, wherein the initial loop tack value is from about 3 and about 15 ounce force per 0.125 inch2and remains in said range for up to about 4 weeks, when measured in accordance with ASTM D6195-03; and(ii) has a water dispersibility of greater than about 80% when measured in accordance with TAPPI UM666.

2. The water dispersible hot melt adhesive of claim 1, wherein the rosin tackifier comprises a modified rosin ester, a styrenated terpene resin, a phenolic terpene resin, or any combination of any of the foregoing.

3. The water dispersible hot melt adhesive of any one of claims 1-2, wherein the rosin tackifier comprises a modified rosin ester.

4. The water dispersible hot melt adhesive of any one of claims 1-3, wherein the tackifier comprises a rosin ester modified with maleic anhydride, glycidyl methacrylate, butyl acrylate, methyl methacrylate, propenoic acid, vinyltrimethoxysilane, or any combination of any of the foregoing.Attorney Docket No.: 2024PF00172WO-shl5. The water dispersible hot melt adhesive of any one of claims 1-4, wherein the tackifier comprises a rosin ester modified with maleic anhydride.

6. The water dispersible hot melt adhesive of any one of claims 1-5, wherein the plasticizer comprises polyethylene glycol, a sebacate, an adipate, a terephthalate, a dibenzoate, a glutarate, a phthalate, an azelate, or any combination of any of the foregoing.

7. The water dispersible hot melt adhesive of any one of claims 1-6, wherein the plasticizer comprises polyethylene glycol.

8. The water dispersible hot melt adhesive of any one of claims 1-7, wherein the adhesive comprises:(i) between about 5 % w / w and about 90 % w / w of a sulfopolyester;(ii) between about 5 % w / w and about 90 % w / w of polyethylene glycol; and(iii) between about 5 % w / w and about 90 % w / w of a maleic anhydride modified rosin ester, a phenolic terpene, a styrenated terpene, or any combination thereof.

9. The water dispersible hot melt adhesive of any one of claims 1-8, wherein the sulfopolyester has(i) a glass transition temperature (Tg) of between about -20° C and about 65° C, such as between about 0° C and about 52° C;(ii) a melt viscosity of between about 1000 and about 150,000 cPs, such as between about 5,000 and about 50,000 cPS (e.g., measured at 177° C); or(iii) both (i) and (ii).

10. The water dispersible hot melt adhesive of any one of claims 1-9, wherein the tackifier has:(i) an acid value of between about 5 and about 100;Attorney Docket No.: 2024PF00172WO-shl(ii) a softening point of between about 0° C and about 150° C; or(iii) both (i) and (ii).

11. The water dispersible hot melt adhesive of any one of claims 1-10, wherein the adhesive has a water dispersibility of greater than about 95%, when measured in accordance with TAPPI UM666.

12. The water dispersible hot melt adhesive of any one of claims 1-10, wherein the adhesive has a viscosity of between about 2,000 cPs and about 15,000 cPs when measured at 250°F, in accordance with ASTM D3236.

13. An article of manufacture comprising a water dispersible hot melt adhesive of any one of claims 1-12.

14. The article of manufacture of claim 13, wherein the article of manufacture is a bag, a tissue, a paper towel, a kitchen towel, toilet paper, an industrial towel, a note pad, a sticky note, or a tape.

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