WO2020047031A1

WO2020047031A1 - Hot melt adhesive containing phase changing materials

Info

Publication number: WO2020047031A1
Application number: PCT/US2019/048462
Authority: WO
Inventors: Jinyu Chen; Patrick Hayes; Geoffrey SILVER; Edwin Clay KELLAM; Benjamin BIBER
Original assignee: Henkel IP & Holding GmbH
Priority date: 2018-08-29
Filing date: 2019-08-28
Publication date: 2020-03-05

Abstract

Disclosed is a hot melt adhesive composition comprising a hot melt adhesive in combination with a phase change material. The phase change material provides thermal regulatory characteristics to the hot melt adhesive. Preferably the phase change material is a microencapsulated organic wax having a melting temperature of from 5 to 80º C and a latent heat of fusion of from 40 to 300 Joules/gram. The addition of the phase change material increases the storage modulus, viscosity and enthalpy of the hot melt adhesive composition while maintaining the adhesive strength of the hot melt adhesive. The phase change materials find use in any hot melt adhesive composition.

Description

HOT MELT ADHESIVE CONTAINING PHASE CHANGING MATERIALS

FIELD OF THE DISCLOSURE

[0001] This present disclosure relates generally to hot melt adhesives, and more particularly to hot melt adhesives having phase changing materials in them.

BACKGROUND OF THE DISCLOSURE

[0002] This section provides background information which is not necessarily prior art to the inventive concepts associated with the present disclosure.

[0003] Hot melt adhesive compositions can be thermoplastic hot melt adhesive compositions or reactive hot melt adhesive compositions. Thermoplastic hot melt adhesive compositions are solid at room temperature but, upon application of heat, melt to a liquid or fluid state in which molten form they are applied to a substrate. On cooling, the adhesive composition regains its solid form. The hard phase(s) formed upon cooling the adhesive composition impart all of the cohesion (strength, toughness, creep and heat resistance) to the final bond. Thermoplastic hot melt adhesive compositions do not cure and can be heated to a fluid state and cooled to a solid state repeatedly. Thermoplastic hot melt adhesive compositions do not include water or solvents.

[0004] Reactive or curable hot melt adhesive compositions are also solid at room temperature and, upon application of heat, melt to a liquid or fluid state in which molten form they are applied to a substrate. On cooling, the adhesive composition regains its solid form. The hard phase(s) formed upon cooling the adhesive composition and prior to curing impart initial or green strength to the bond. These adhesive compositions will cure by a chemical crosslinking reaction upon exposure to suitable conditions such as exposure to moisture. Before curing the adhesive composition remains thermoplastic and can be remelted and resolidified. Once cured, the adhesive composition is in an irreversible solid form and is no longer thermoplastic. The crosslinked adhesive composition provides additional strength, toughness, creep and heat resistance to the final bond. Curable hot melt adhesive compositions can provide higher strength and heat resistance compared to thermoplastic hot melt adhesive compositions. Reactive hot melt adhesive compositions do not include water or solvents. [0005] The majority of reactive hot melts are moisture-curing urethane hot melt compositions. The reactive components of urethane hot melt compositions consist primarily of isocyanate terminated polyurethane prepolymers containing urethane groups and reactive isocyanate groups that react with surface or atmospheric moisture to cross-link and form a new polyurethane polymer. Polyurethane prepolymers are conventionally obtained by reacting polyols with diisocyanates. Upon cooling the isocyanate groups in the polyurethane prepolymer react with moisture from the environment to form a crosslinked irreversible solid bond.

[0006] Neither thermoplastic nor reactive or melt adhesives are capable of providing any temperature regulating properties to the substrates that are bonded to the adhesive. It is desirable to provide a hot melt adhesive composition that can, in addition to bonding to materials , also provide temperature regulating properties to the bonded materials or to the bond itself wherein the temperature regulation characteristics do not negatively affect the bond integrity.

SUMMARY OF THE DISCLOSURE

[0007] This section provides a general summary of the present disclosure and is not intended to be interpreted as a comprehensive disclosure of its full scope or all features, aspects and objectives.

[0008] One aspect of the present disclosure is a hot melt adhesive composition comprising: 1 to 99 %, preferably 35 to 99%, by weight of one or more resins, based on a total weight of the composition; 1 to 65 % by weight of a phase change material (PCM), based on the total weight of the composition. The PCM has a melting temperature of from 5 to 80° C and a latent heat of fusion of from 40 to 300 Joules/ gram.

[0009] Another aspect of the disclosure is a composition having a storage modulus

(G’25) at 25° C of from about 1X10³ to about 1X10⁸ Pascal, a storage modulus (G’40) at 40° C of from about 1X10² to about 1X10⁷ Pascal and a viscosity at 160° C of less than 100,000 centipoise.

[00010] Another aspect of the present disclosure is a hot melt adhesive wherein the phase change material is a microencapsulated organic wax. [00011] Another aspect of the present disclosure is a hot melt adhesive composition comprising at least one homopolymer or a copolymer formed from one or more C₂ to Cio olefin monomers and 1 to 65 % by weight of a phase change material (PCM), based on the total weight of the composition. The PCM has a melting temperature of from 5 to 80° C and a latent heat of fusion of from 40 to 300 Joules/ gram.

[00012] Another aspect of the present disclosure is a hot melt adhesive comprising a poly ethylene vinyl acetate copolymer and/or polyethylene n-butyl acrylate as a resin and 1 to 65 % by weight of a phase change material (PCM), based on the total weight of the composition. The PCM has a melting temperature of from 5 to 80° C and a latent heat of fusion of from 40 to 300 Joules/ gram.

[00013] Another aspect of the present disclosure is a hot melt adhesive comprising a rubber derived component and 1 to 65 % by weight of a phase change material (PCM), based on the total weight of the composition. The PCM has a melting temperature of from 5 to 80° C and a latent heat of fusion of from 40 to 300 Joules/ gram.

[00014] Another aspect of the present disclosure is a hot melt adhesive comprising a resin selected from the group consisting of styrene-isoprene-styrene (SIS) rubbers, styrene- butadiene-styrene (SBS) rubbers, styrene-ethylene-butadiene-styrene (SEBS) rubbers, styrene- ethylene-isoprene-styrene (SEIS) rubbers, and mixtures thereof and 1 to 65 % by weight of a phase change material (PCM), based on the total weight of the composition. The PCM has a melting temperature of from 5 to 80° C and a latent heat of fusion of from 40 to 300 Joules/ gram.

[00015] Another aspect of the present disclosure is a hot melt adhesive comprising a resin selected from the group consisting of an isocyanate functional polyurethane oligomer or prepolymer or a silane modified polymer, and 1 to 65 % by weight of a phase change material (PCM), based on the total weight of the composition. The PCM has a melting temperature of from 5 to 80° C and a latent heat of fusion of from 40 to 300 Joules/ gram.

[00016] These and other features and advantages of this disclosure will become more apparent to those skilled in the art from the detailed description herein. The drawings that accompany the detailed description are described below. BRIEF DESCRIPTION OF THE DRAWINGS

[00017] The drawings described herein are for illustrative purposes only of selected aspects and not all implementations and are not intended to limit the present disclosure to only that actually shown. With this in mind, various features and advantages of example aspects of the present disclosure will become apparent to one possessing ordinary skill in the art from the following written description and appended claims when considered in combination with the appended drawings, in which:

[00018] FIG. 1 shows the specific heat capacity, Cp, tracings of a series of hot melt adhesives in accordance with the present disclosure compared to a control hot melt adhesive;

[00019] FIG. 2 is a Scanning Electron Micrograph (SEM) photograph of a hot melt adhesive composition comprising 10% of a phase change material (PCM);

[00020] FIG. 3 is an SEM photograph of a hot melt adhesive composition comprising 300% of a PCM;

[00021] FIG. 4 is an SEM photograph of a hot melt adhesive composition comprising 50% of a PCM;

[00022] FIG. 5 is an SEM photograph of a surface of a comparative hot melt adhesive composition comprising 100% of a polyurethane hot melt adhesive, not in accordance with the present disclosure;

[00023] FIG. 6 is an SEM photograph of a surface of a hot melt adhesive composition comprising 90% of a polyurethane hot melt adhesive and 10 % of a PCM;

[00024] FIG. 7 is an SEM photograph of a cross-section of the surface shown in FIG. 6;

[00025] FIG. 8 is an SEM photograph of a surface of a hot melt adhesive composition comprising 70% of a polyurethane hot melt adhesive and 30 % of a PCM;

[00026] FIG. 9 is an SEM photograph of a cross-section of the surface shown in FIG. 8;

[00027] FIG. 10 is an SEM photograph of a surface of a hot melt adhesive composition comprising 50% of a polyurethane hot melt adhesive and 50 % of a PCM; and

[00028] FIG. 11 is an SEM of a cross-section of the surface shown in FIG. 10. DETAILED DESCRIPTION OF THE DISCLOSURE

[00029] In the following description, details are set forth to provide an understanding of the present disclosure.

[00030] For clarity purposes, example aspects are discussed herein to convey the scope of the disclosure to those skilled in the relevant art. Numerous specific details are set forth such as examples of specific components, devices, and methods, in order to provide a thorough understanding of various aspects of the present disclosure. It will be apparent to those skilled in the art that specific details need not be discussed herein, such as well-known processes, well- known device structures, and well-known technologies, as they are already well understood by those skilled in the art, and that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure.

[00031] The terminology used herein is for the purpose of describing particular example aspects only and is not intended to be limiting. As used herein, the singular forms“a,”“an,” and“the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms“comprises,”“comprising,”“including,” and“having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[00032] When an element or feature is referred to as being “on,” “engaged to,” “connected to,”“coupled to”“operably connected to” or“in operable communication with” another element or feature, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or features may be present. In contrast, when an element is referred to as being“directly on,”“directly engaged to,”“directly connected to,” or “directly coupled to” another element or feature, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g.,“between” versus“directly between,”“adjacent” versus“directly adjacent,” etc.). As used herein, the term“and/or” includes any and all combinations of one or more of the associated listed items.

[00033] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These ter may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as“first,”“second,” and other numerical terms when used herein do not imply a sequence or order unless clearly and expressly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[00034] For purposes of description herein, the terms "upper," "lower," "right," "left," "rear," "front," "vertical," "horizontal," and derivatives thereof shall relate to the invention as oriented in the FIGS. However, it is to be understood that the present disclosure may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are exemplary aspects of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the aspects disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

[00035] The disclosed compounds include any and all isomers and stereoisomers. In general, unless otherwise explicitly stated the disclosed materials and processes may be alternately formulated to comprise, consist of, or consist essentially of, any appropriate components, moieties or steps herein disclosed. The disclosed materials and processes may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants, moieties, species and steps used in the prior art compositions or that are otherwise not necessary to the achievement of the function and/or objective of the present disclosure. The word“about” or“approximately” as used herein in connection with a numerical value refer to the numerical value ± 10%, preferably ± 5% and more preferably ± 1% or less. Unless explicitly indicated otherwise, all percentages that are cited in connection with the compositions described herein refer to wt.% with respect to final composition with all components.

[00036] Unless indicated otherwise, the molecular weights indicated in the present text refer to the number average of the molecular weight (Mn). The molecular weight Mn can be determined based on an end group analysis (hydroxyl number according to DIN 53240-1 :2013- 06 or NCO content according to EN ISO 11909), or by means of gel permeation chromatography (GPC) according to DIN 55672-1 :2007-08 with THF as an eluent. Except where indicated otherwise, the listed molecular weights are those which are determined by means of GPC. The weight average of the molecular weight Mw can also be determined by means of GPC, as indicated previously.

[00037] The present disclosure is directed to inclusion of phase change materials in either thermoplastic hot melt adhesive compositions or reactive hot melt adhesive compositions. These phase change materials will provide thermal regulating characteristics to the hot melt adhesives. A phase change material is defined as a material that can both absorb and release large amounts of energy, typically in the form of heat, from or into the environment depending on the temperature in the environment relative to the melting temperature of the phase change material. The most common phase changes for a phase change material are to go between the phases of a solid and a liquid. When the phase change material is in the solid phase it can absorb energy/heat to provide a cooling effect and when it is in the liquid phase it can release energy/heat to provide a heating effect. The phase change material cycles between the two phases as the external temperature goes above or below its melt point. As the external temperature rises toward the melt temperature the phase change material heats up until it reaches its melt temperature and then it absorbs heat until it is fully melted, thus maintaining a surrounding temperature at or near the melt temperature. During this period the phase change material is providing a cooling effect by maintaining the surrounding environmental temperature. Then, once the latent heat of fusion of the material is exceeded and it is fully melted, the phase change material starts to heat as the external temperature continues to rise and it is in a fully liquid state. When the external temperature decreases toward the melt temperature of the phase change material the opposite cycle occurs and as the phase change material solidifies it releases heat to the environment to maintain a temperature at or near its melt temperature. The latent heat of fusion of a phase change material determines its capacity for absorbing and releasing energy and it is generally expressed in Joules/gram. The present disclosure relies on organic phase change materials which have several advantages over inorganic or eutectic phase change materials. The organic phase change materials generally are chemically stable, have high enthalpy meaning heat storage capacity, are non-reactive with other components of the hot melt composition and can be repeatedly cycled from one phase to another (liquid to solid to liquid) with no loss of effectiveness. The thermal regulation these phase change materials provide is passive in that it is provided by the material itself with no requirement for electricity or other input in addition to the environmental temperature. The specific phase change materials finding use in the present disclosure are waxes and more specifically microencapsulated waxes.

[00038] The types of waxes that find use as phase change materials in the present disclosure include organic waxes found as natural waxes, partially synthetic organic waxes and fully synthetic organic waxes. Waxes are water insoluble and are generally malleable solids at temperatures below their melting temperatures. Natural organic waxes are those that are products of animals, insects, and plants or extracted from petroleum, coal or lignite. Animal and insect derived waxes tend to be composed of esters formed from long chain alcohols, generally C12 to C₃₂, and long chain fatty acids such as Cio to C₂₈. A well know insect wax is beeswax which has the ester form of CH₃-(CH₂)₂₈-CH₂0-C(=0)-(CH₂)i₄-CH3. The sperm whale was the source of spermacetic, another previously used organic wax, and sheep’s wool contains lanolin another organic wax. The most plentiful plant wax is the organic wax camauba wax. Plant waxes tend to be substituted long chain aliphatic hydrocarbons containing alkanes, alkyl esters, fatty acids, primary and secondary alcohols, diols, ketones and aldehydes. Two types of organic waxes extracted from petroleum are paraffins and microcrystalline wax. Paraffins tend to be composed of a variety of long straight and branched chain alkanes, C₂₀ to C₄o, whereas microcrystalline waxes tend to be composed of substantial portions of branched and cyclic saturated alkanes along with straight chain alkanes. Extraction of coal and/or lignite produces the organic wax known as montan wax. Partially synthetic organic waxes are formed by chemically reacting natural waxes. Fully synthetic organic waxes are prepared by polymerizing low molar mass starting materials such as carbon, methane, ethane or propane. The two main groups of fully synthetic waxes are the Fischer-Tropsch waxes and the polyolefin waxes, such as, polyethylene wax, polypropylene wax and copolymers thereof. The Fischer- Tropsch waxes are the product of polymerization of CO under high pressure. Other synthetic waxes include the alpha olefin waxes. In the present disclosure all organic waxes find use in the disclosure provided they have the following characteristics: a melting temperature in the range of from 5 to 80° C; a latent heat of fusion of from 40 to 300 Joules/gram; and the waxes are microencapsulated. More preferably, the organic waxes of the present disclosure have a melting temperature of from 10 to 50° C; a latent heat of fusion of from 100 to 200 Joules/gram; and are microencapsulated. When the phase change materials of the present disclosure are utilized in a thermoplastic hot melt adhesive then the melting temperature of the microencapsulated wax is selected to be below the softening temperature of the hot melt adhesive so as to avoid any loss of adhesion by the hot melt adhesive.

[00039] In some embodiments the organic waxes used as phase change materials in the present disclosure are microencapsulated waxes, meaning the wax is microencapsulated in a capsule or shell. The shell is preferably non-reactive with other components of the hot melt composition. Such microencapsulated waxes are available commercially from companies such as Microtek Laboratories, Inc in Dayton OH. The waxes can be encapsulated in any suitable shell material with melting point above 200°C. Some exemplary shell materials comprise poly(urea-urethane) (PU) composite, graphene, polymethylmethacrylate, polystyrene etc. Typically, these microencapsulated waxes have shell or particles sizes of from 2 to 30 microns in diameter. The organic microencapsulated waxes find use in any form of hot melt adhesive, both thermoplastic and reactive. The hot melt adhesive compositions according to the present disclosure preferably comprise about 1 to 65% by weight of microencapsulated waxes, based on the total weight of the hot melt adhesive composition. As discussed above, preferably the microencapsulated waxes have a melting temperature of from 5 to 80° C and a latent heat of fusion of from 40 to 300 Joules/gram, and more preferably a melting temperature of from 10 to 50° C and a latent heat of fusion of from 100 to 200 Joules/gram.

[00040] The hot melt adhesive compositions according to the present disclosure further comprise about 1 to 99% by weight, based on the total weight of the hot melt adhesive composition, of a resin. In one embodiment directed to thermoplastic hot melt adhesives the resin is olefin-based, meaning a majority of the adhesive component is an olefin derived component. These hot melt adhesives comprise homopolymers of C₂ to Cio olefin monomers or copolymers of mixtures of these monomers. In another embodiment the hot melt adhesive is poly ethylene vinyl acetate (PEVA) and/or ethylene n-butyl acrylate( PEBA) based, meaning the majority of the hot melt adhesive resin is a PEVA or PEBA derived component. These hot melt adhesives comprise one or more PEVA and/or PEBA copolymers. The poly ethylene vinyl acetate copolymers are copolymers of ethylene and vinyl acetate and poly ethylene n-butyl acrylate copolymers are copolymer of ethylene and n-butyl acrylate. The weight percent vinyl acetate or n-butyl acrylate in a copolymer usually varies from 4 to 40%, with the remainder being ethylene. In another embodiment the hot melt adhesive is a rubber based hot melt adhesive, meaning the majority of the adhesive is a rubber derived component. These hot melt adhesives comprise one or more rubbers preferably selected from styrene-isoprene-styrene (SIS) rubbers, styrene-butadiene-styrene (SBS) rubbers, styrene-ethylene-butadiene-styrene (SEBS) rubbers, styrene-ethylene-isoprene-styrene (SEIS) rubbers, and mixtures thereof.

[00041] In one embodiment directed to reactive hot melt adhesive the resin is typically an isocyanate functional polyurethane oligomer or prepolymer (together “prepolymer”). Reaction of moisture with isocyanate functionality on the polyurethane oligomer crosslinks the oligomers together into a cured mass. The isocyanate (NCO)-terminated polyurethane prepolymers are obtained by reacting a polyol or a polyol mixture with a stoichiometric excess of polyisocyanate. The polyols used when producing the prepolymer may be all polyols that are usually used for polyurethane synthesis, for example polyester polyols, polyether polyols, polyester ether polyols, polycarbonate polyols or mixtures of two or more thereof.

[00042] Polyether polyols may be produced from a plurality of alcohols, which contain one or more primary or secondary alcohol groups. As an initiator for the production of polyethers that do not contain any tertiary amino groups, the following compounds or mixtures of said compounds can be used by way of example: water, ethylene glycol, propylene glycol, glycerol, butanediol, butanetriol, trimethylolethane, pentaerythritol, hexanediol, 3-hydroxyphenol, hexenetriol, trimethylolpropane, octanediol, neopentyl glycol, 1,4-hydroxymethyl cyclohexane, bis(4-hydroxyphenyl)dimethylmethanes and sorbitol. Ethylene glycol, propylene glycol, glycerol and trimethylolpropane are preferably used, particularly preferably ethylene glycol and propylene glycol, and, in a particularly preferred embodiment, propylene glycol is used.

[00043] As cyclic ethers for producing the above-described polyethers, alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, styrene oxide or tetrahydrofuran or mixtures of these alkylene oxides may be used. Propylene oxide, ethylene oxide or tetrahydrofuran or mixtures thereof are preferably used. Propylene oxide or ethylene oxide or mixtures thereof are preferably used. Propylene oxide is most particularly preferably used.

[00044] Polyester polyols can be produced for example by reacting low molecular weight alcohols, in particular ethylene glycol, diethylene glycol, neopentyl glycol, hexanediol, butanediol, propylene glycol, glycerol, or trimethylolpropane with caprolactone. 1,4-hydroxymethylcyclohexane, 2-methyl- 1,3 -propanediol, 1,2,4-butanetriol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycol are also suitable as polyfunctional alcohols for producing polyester polyols.

[00045] Further suitable polyester polyols may be produced by polycondensation. Difunctional and/or trifunctional alcohols having an insufficient amount of dicarboxylic acids or tricarboxylic acids or mixtures of dicarboxylic acids or tricarboxylic acids, or reactive derivatives thereof, may thus be condensed to form polyester polyols. Suitable dicarboxylic acids are, for example, adipic acid or succinic acid or dodecanedioic acid and higher homologs thereof having up to 16 carbon atoms, also unsaturated dicarboxylic acids such as maleic acid or fumaric acid and aromatic dicarboxylic acids, in particular isomeric phthalic acids, such as phthalic acid, isophthalic acid or terephthalic acid. Suitable tricarboxylic acids are for example citric acid or trimellitic acid. The aforementioned acids can be used individually or as mixtures of two or more thereof. Particularly suitable alcohols are hexane diol, butane diol, ethylene glycol, diethylene glycol, neopentyl glycol, 3 -hydroxy-2, 2-dimethylpropyl-3 -hydroxy-2, 2- dimethylpropanoate or trimethylolpropane or mixtures of two or more thereof. Polyester polyols having a high molecular weight include for example the reaction products of polyfunctional, preferably difunctional, alcohols (optionally together with small amounts of trifunctional alcohols) and polyfunctional, preferably difunctional carboxylic acids. Instead of free polycarboxylic acids, the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters can also be used (where possible) with alcohols having preferably 1 to 3 carbon atoms. The polycarboxylic acids can be aliphatic, cycloaliphatic, aromatic or heterocyclic, or both. They can optionally be substituted, for example by alkyl groups, alkenyl groups, ether groups or halogens. Suitable polycarboxylic acids are, for example, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, phthalic acid anhydride, tetrahydrophthalic acid anhydride, hexahydrophthalic acid anhydride, tetrachlorophthalic acid anhydride, endomethylene tetrahydrophthalic acid anhydride, glutaric acid anhydride, maleic acid, maleic acid anhydride, fumaric acid, dimer fatty acid or trimer fatty acid, or mixtures of two or more thereof.

[00046] Polyesters that can be obtained from lactones, for example based on epsilon- caprolactone, also referred to as“polycaprolactone”, or hydroxycarboxylic acids, for example omega-hydroxy caproic acid, can also be used.

[00047] Polyester polyols of oleochemical origin can also be used. Polyester polyols of this kind can be produced, for example, by complete ring opening of epoxidized triglycerides of a fat mixture that contains an at least partially olefmically unsaturated fatty acid and has one or more alcohols having 1 to 12 carbon atoms and subsequent partial transesterification of the triglyceride derivatives to form alkyl ester polyols having 1 to 12 carbon atoms in the alkyl group.

[00048] Polycarbonate polyols can be obtained, for example, by reacting diols such as propylene glycol, butanediol-1,4 or hexanediol-1,6, diethylene glycol, triethylene glycol or tetraethylene glycol or mixtures of said diols with diaryl carbonates, for example diphenyl carbonates, or phosgene.

[00049] The molecular weight of the polyols used for synthesizing the prepolymer is preferably in the range of from 100 to 20,000 g/mol, in particular 330 to 4,500 gmol. The average functionality can be in the range of from 2 to 4.5. The PU prepolymer preferably comprises a polyether and/or polyester backbone. [00050] The stoichiometric excess of polyisocyanate, based on the molar ratio of NCO to OH groups, is in particular 1 : 1 to 2.5:1, preferably 1 :1 to 2:1 and particularly preferably 1.05: 1 to 1.8:1.

[00051] The known coating or adhesive polyisocyanates may be used, these being polyisocyanates having two or more isocyanate groups. Suitable polyisocyanates are, for example, 1,5-naphthylene diisocyanate (NDI), 2,4- or 4,4’-diphenylmethane diisocyanate (MDI), hydrogenated MDI (H12MDI), xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI), di- and tetra alkylene diphenylmethane diisocyanate, 4,4’-dibenzyl diisocyanate, 1,3- or 1,4-phenylene-diisocyanate, toluylene diisocyanate (TDI), 1 -methyl-2, 4- diisocyanato-cyclohexane, 1 ,6-diisocyanato-2,2,4-trimethylhexane, 1 ,6-diisocyanato-2,4,4- trimethylhexane, l-isocyanatomethyl-3-isocyanato-l,5,5-trimethylcyclohexane (IPDI), tetramethoxybutane- 1 ,4-diisocyanate, butane- 1 ,4-diisocyanate, hexane- 1 ,6-diisocyanate (HDI), dicyclohexylmethane diisocyanate, cyclohexane- 1,4-diisocyanate, ethylene diisocyanate, methylene triphenyl triisocyanate (MIT), phthalic acid-bis-isocyanato-ethylester, trimethylhexamethylene diisocyanate, 1,4-diisocyanatobutane, 1,12-diisocyanatododecane and dimer fatty acid diisocyanate.

[00052] Suitable at least trifunctional isocyanates are polyisocyanates which are obtained by trimerization or oligomerization of diisocyanates or by reaction of diisocyanates with low molecular weight polyfunctional compounds containing hydroxyl or amino groups. Commercially available examples are trimerization products of the isocyanates HDI, MDI or IPDI or adducts of diisocyanates and low molecular weight triols, such as trimethylolpropane or glycerol. Further examples include isocyanurates of hexamethylene diisocyanate (HDI) and isocyanurates of isophorone diisocyanate (IPDI).

[00053] Aliphatic, cycloaliphatic, or aromatic isocyanates may in principle be used, but aromatic isocyanates are particularly suitable on account of the reactivity. Examples of suitable diisocyanates are methylene diphenyl diisocyanates (MDI), such as 4,4' -methylene diphenyl diisocyanate, 2,4^' -methylene diphenyl diisocyanate or 2,2'- methylene diphenyl diisocyanate. [00054] The prepolymers usually have an NCO content of from 0.25 to 5 wt.% (determined according to Spielberger, DIN EN ISO 11909:2007-05), preferably 0.25 to 4 wt.%, and have an average NCO functionality of from 2 to 3, in particular 2.

[00055] The molecular weight (Mn) of the prepolymer is in the range of from 300 to 20,000 g/mol, preferably less than 12,000, in particular less than 8,000 g/mol.

[00056] In one embodiment directed to reactive hot melt adhesive the resin is typically a silane modified polymer. Silane modified polymers and their preparation are known in the art and are described in, for example, U.S. Patent No. 9212300 and U.S. Patent No. 9023946. Silane modified polymers comprise pendant or terminal silyl alkoxy groups. Reaction of moisture with silyl alkoxy functionality crosslinks the polymers together into a cured mass.

[00057] The thermoplastic hot melt adhesive compositions according to the present disclosure exhibit the following characteristics. Thermoplastic hot melt adhesive compositions have a storage modulus (G’₂₅) of from about 1X10³ to about 1X10⁸ Pascal at 25° C and more preferably from about 1X10⁴ to about 1X10⁷ Pascal at 25° C, 10 rad/s. They have a storage modulus (G’₄₀) of from about 1X10² to about 1X10⁷ Pascal at 40° C and more preferably from about 1X10³ to about 1X10⁶ Pascal at 40° C, 10 rad/s.

[00058] The thermoplastic hot melt adhesive compositions have a viscosity at 160° C of less than 100,000 centipoise (cps), more preferably from 500 to 100,000 cps at 160° C and most preferably from about 1,000 to 40,000 cps at 160° C. The reactive hot melt adhesive compositions have a viscosity at 121° C of less than 150,000 centipoise (cps), more preferably from 1,000 to 85,000 cps at 121° C and most preferably from about 5,000 to 45,000 cps at 121° C.

[00059] The hot melt adhesive composition can optionally comprise a tackifier. The choice of tackifier will depend on the backbone of the hot melt adhesive. The tackifier choices include natural and petroleum-derived materials and combinations thereof as described in C.W. Paul,“Hot Melt Adhesives,” in Adhesion Science and Engineering-2, Surfaces, Chemistry and Applications, M. Chaudhury and A. V. Pocius eds., Elsevier, New York, 2002, p. 718, incorporated by reference herein.

[00060] Useful tackifiers for the hot melt adhesive composition of the present disclosure include natural and modified rosin, aromatic tackifiers or mixtures thereof. Useful natural and modified rosins include gum rosin, wood rosin, tall oil rosin, distilled rosin, hydrogenated rosin, dimerized rosin, resinates, and polymerized rosin; glycerol and pentaerythritol esters of natural and modified rosins, including, 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. Examples of commercially available rosins and rosin derivatives that could be used to practice the present disclosure include Sylvalite RE 110L, Sylvares RE 115, and Sylvares RE 104 available from Arizona Chemical; Dertocal 140 from DRT; Limed Rosin No.l,GB-120, and Pencel C from Arakawa Chemical. One preferred natural and modified rosin is a rosin ester tackifier such as KE-100, available from Arakawa Chemical Co. Another preferred rosin ester tackifier is a Komotac 2110 from Komo Resins. Useful aromatic tackifiers include styrenic monomers, styrene, alpha-methyl styrene, vinyl toluene, methoxy styrene, tertiary butyl styrene, chlorostyrene, coumarone, indene monomers including indene, and methyl indene. Preferred are aromatic hydrocarbon resins that are phenolic-modified aromatic resins, C9 hydrocarbon resins, aliphatic-modified aromatic C9 hydrocarbon resins, C9 aromatic/aliphatic olefin- derived and available from Sartomer and Cray Valley under the trade name Norsolene and from Rutgers series of TK aromatic hydrocarbon resins. Other preferred aromatic tackifiers are alpha-methyl styrene types such as Kristalex 3100, Kristalex 5140 or Hercolite 240, all available from Eastman Chemical Co.

[00061] When present, the tackifier component will usually be present in an amount of from about 1 to about 80 % by weight based on the total weight of the hot melt adhesive composition, more preferably from about 15 to about 65 % by weight, and most preferably from about 20 to about 50 % by weight.

[00062] The hot melt adhesive composition can optionally comprise an acrylic or methacrylic polymer or copolymer (acrylic polymer). The acrylic polymer can improve the green strength of the cooled hot melt adhesive composition. The acrylic polymer can be either a reactive polymer or a non-reactive polymer. A reactive polymer comprises groups such as carboxylic acid, amine, thiol and hydroxyl that react with other hot melt components. A preferred reactive group is carboxylic acid. The number of groups should be sufficient such that a significant amount, at least 5%, of the acrylic polymer can be grafted to any polymer. A non-reactive acrylic polymer does not include groups that are reactive with other hot melt components.

[00063] Some useful reactive acrylic polymers are Elvacite 2903, a solid acrylic copolymer comprising acid and hydroxyl groups with an acid number 5.2 and a hydroxyl number of 9.5; Elvacite 2978 with an acid number of 3.5 and hydroxyl number of 2.2; Elvacite 4014 with an acid number of 3.3 and hydroxyl number of 1.3; Elvacite 4155 with an acid number of 3.5 and hydroxyl number of 1.1; and Elvacite 2902 with an acid number of 5 and hydroxyl number of 6; all available from Lucite International

[00064] The amount of solid acrylic polymer in the hot melt adhesive composition will depend on a number of factors, including the glass transition temperature and molecular weight of the acrylic polymer. The acrylic polymer is optionally present and if used will typically be present in an amount of from about 1 to about 45 % by weight, based on the total weight of the hot melt adhesive composition.

[00065] The reactive hot melt adhesive composition can optionally comprise a catalyst. Exemplary catalysts include bismuth compounds such as bismuth carboxylate; organic tin catalysts such as dimethyltin dineodecanoate, dibutyltin oxide and dibutyltin diacetate; titanium alkoxides (TYZOR® types, available from DuPont); tertiary amines such as bis (2- morpholinoethyl) ether, 2,2'-Dimorpholino Diethyl Ether (DMDEE) and triethylene diamine; zirconium complexes (KAT XC6212, K-KAT XC-A209 available from King Industries, Inc.); aluminum chelates (K-KAT 5218, K-KAT 4205 available fromKing Industries, Inc.), KR types (available from Kenrich Petrochemical, Inc.); and other organometallic compounds based on Zn, Co, Ni, and Fe and the like. The level of catalyst in the reactive hot melt adhesive composition will depend on the type of catalyst used but can range from about 0.05 to about 5 % by weight, advantageously from about 0.1 to about 3 % and more advantageously from about 0.1 to about 2 %, based on the total weight of the hot melt adhesive composition.

[00066] The reactive hot melt adhesive composition can optionally comprise a moisture scavenger to extend pot life, such as vinyl trimethoxy silane or methacryloxypropyltrimethoxysilane. The level of moisture scavenger employed can be from 0 to 3% by weight and preferably from 0 to 2%, based on the total weight of the hot melt adhesive composition. [00067] The hot melt adhesive composition can also comprise an adhesion promoter or coupling agent which promotes bonding of the composition to a substrate. Examples are described in: Michel J. Owen,“Coupling agents: chemical bonding at interfaces”, in Adhesion Science and Engineering-2, Surfaces, Chemistry and Applications, M. Chaudhury and A. V. Pocius eds., Elsevier, New York, 2002, p. 403, incorporated by reference herein. Preferred adhesion promoters include organo-silanes which can link the silane-functional polymer to the surface such as amino silanes and epoxy silanes. Some exemplary aminosilane adhesion promoters include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2- aminoethyl-3 -aminopropyl)trimethoxysilane, 3 -aminopropylmethyldiethoxysilane, 4-amino- 3,3-dimethylbutyltrimethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, 1- butanamino-4-(dimethoxymethylsilyl)-2, 2-dimethyl, (N- cyclohexylaminomethyl)triethoxysilane, (N-cyclohexylaminomethyl)-methyldiethoxysilane, (N-phenylaminoethyl)trimethoxysilane, (N-phenylaminomethyl)-methyldimethoxysilane or .gamma.-ureidopropyltrialkoxysilane. Particularly preferred amino silanes include 3- aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane. Some exemplary epoxy silane adhesion promoters include 3-glycidyloxypropyltrimethoxysilane, 3- glycidyloxypropyltriethoxysilane or beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Other silane adhesion promoters include mercaptosilanes. Some exemplary mercaptosilane adhesion promoters include 3-mercaptopropyltrimethoxysilane, 3- mercaptopropylmethyldimethoxysilane or 3-mercaptopropyltriethoxysilane. The level of adhesion promoter employed can be from 0 to 10%, preferably 0.1 to 5% and more preferably 0.2-3% by weight based on the total weight of the hot melt adhesive composition. The adhesion promoter, if more reactive to moisture than with the polymers, can also serve as a moisture scavenger.

[00068] The hot melt adhesive composition can optionally comprise conventional additives known to a person skilled in the art. Conventional additives which are compatible with a composition according to this invention may simply be determined by combining a potential additive with the composition and determining if they remain homogenous. Nonlimiting examples of suitable additives include, without limitation, antioxidants, fillers, plasticizers, defoamers, rheology modifiers, air release agents and flame retardants. The total level of additives will vary depending on amount of each particular additive needed to provide the hot melt adhesive composition with desired properties. The level of additives can be from 0 to 50 % by weight based on the total weight of the hot melt adhesive composition.

[00069] An exemplary hot melt adhesive composition is shown below. Percentages are based on weight of the hot melt adhesive composition.

[00070] The hot melt adhesive composition is preferably free of water and/or solvent in either the solid and/or molten form. The hot melt adhesive composition can be prepared by mixing the phase change material, tackifier, and other non-hot melt adhesive components with heat until homogeneously blended. The mixture is placed under vacuum to remove moisture followed by heated mixing of the hot melt adhesive into the composition.

[00071] The hot melt adhesive compositions can be used to bond articles together by applying the hot melt adhesive composition in molten form to a first article, bringing a second article in contact with the molten composition applied to the first article. After application of the second article the hot melt adhesive composition is subjected to conditions that will allow it to solidify, bonding the first and second articles. Solidification occurs when the liquid melt is subjected to a temperature below the melting point, typically room temperature. Bonding based on solidification and before cure is referred to as green strength. After solidification the adhesive is exposed to conditions such as surface or atmospheric moisture to cure the solidified composition to an irreversible solid form. [00072] The hot melt adhesive compositions are useful for bonding articles composed of a wide variety of substrates (materials), including but not limited to wood, metal, polymeric plastics, glass and textiles. Non-limiting uses include use in the manufacture of footwear, use in the manufacture of doors including entry doors, garage doors and the like, use in the manufacture of panels, use in bonding components on the exterior of vehicles, and the like. The hot melt adhesives according to the present disclosure also find use in any other location where a hot melt adhesive can be used, more particularly in tapes, labeling, bedding materials, pads, clothing, textiles, electronics, solar panel systems, transport of temperature sensitive materials and other applications.

[00073] Application temperatures of the hot melt adhesive compositions are determined by the thermal stability of the composition and the heat sensitivity of the substrates. Preferred application temperatures are above 120°C and below 170°C, more preferably below 150°C, and most preferably below 140°C.

[00074] The hot melt adhesive compositions may be then applied in molten form to substrates using a variety of application techniques known in the art. Examples include by a hot melt glue gun, hot melt slot-die coating, hot melt wheel coating, hot melt roller coating, melt blown coating, spiral spray and the like. In preferred embodiments the hot melt adhesive composition is applied to a substrate using hot melt roller coater or extruded onto a substrate.

[00075] The following testing procedures were utilized to evaluate the hot melt adhesive compositions.

[00076] Viscosity was measured with a Brookfield viscometer, spindle #27 at 160°C or 121°C, in accordance with ASTM 3236-88.

[00077] The storage modulus was measured as follows. A TA Dynamic Mechanical Analyzer (ARES-M LS) was used to obtain the elastic moduli (G¹), using a temperature sweep test from Orchestrators software version 7.2.0.4. Steel parallel plates, 25 m in diameter (316 Stainless Steel, Part # 708-00966-1 from TA instruments) and separated by a gap of about 1 mm were used for this test. The sample was loaded and then heated to 160°C and the time sweep at required temperature started once equilibrium 160°C reached. The program test data points every 10 second intervals. The convection oven (type ARES-LN2) was flushed continuously with cool nitrogen gas. The cooling rate is at 5°C/min until reaches 0°C. The convection oven was flushed continuously with nitrogen. The frequency was maintained at 10 rad/s. The initial strain at the start of the test was 50% (at the outer edge of the plates). An autostrain option in the software was used to maintain an accurately measurable torque throughout the test. The option was configured such that the maximum applied strain allowed by the software was 80%. The autostrain program adjusted the strain at each temperature increment if warranted using the following procedure. If the torque was below 19.62xl0 ³ Nm the strain was decrease by 5% of the current value. If the torque was above H7.72xl0 ³ Nm it was decreased by 25% of the current value. At torques between 19.62xl0 ³ and 117.72xl0 ³ Nm no change in strain was made at that temperature increment. The shear storage or elastic modulus (G¹) and the shear loss modulus (G") are calculated by the software from the torque and strain data.

[00078] The peel strength is measured on a tensile machine, at 22+/-l°C and relative humidity 50+/-5%, and at 180° peeling angle of mylar coated with adhesive to a standard steel panel in accordance with ASTM D3330; the shear time is measured by mylar coated with adhesive against a stainless steel panel at 22+/-l°C and relative humidity 50+/-5% in accordance with ASTM Standard Method D 3654 . The coating of adhesive on mylar is 2 mils ( 50 um) thick.

[00079] Peak melting temperature were measured with a DSC, in accordance with ASTM D3418-12, Cp 0-40° C was measured using a modulated mode with ramping rate of 2 °C/ min.

[00080] The wood adhesion tests were performed as follows. An adhesive single lap shear strength test was performed as described in Lap Shear ASTM D5868 Test except that the test substrates described below were used. Two specimens of substrate (pine or maple) each cut to 1” x 4” were bonded together with adhesive and had an overlap of one square inch and a coat weight of 4.1mil on pine and 9.8mil on maple. The bonds were let cure for 5 days before the lap shear test was performed with a cross head control rate of 0.5in/min A wood failure means the wood substrate failed or broke before the adhesive in the test. An adhesive failure means that during the test the sample broke at the adhesive to substrate interface leaving no adhesive on the wood substrate. A cohesive failure means the test sample broke within the adhesive layer, leaving adhesive on the wood substrate. [00081] The specific heat capacity, Cp, of samples was measured using Differential Scanning Calorimetry as known to one of skill in the art.

[00082] The stability over time, expressed as %/hr, was measured as the percentage increase in viscosity of a hot melt adhesive solution at 121.1° C (250° F) over time.

[00083] The disclosure is further illustrated by the following non-limiting examples.

Example 1

[00084] In a first example three hot melt adhesive compositions were prepared: a comparative composition with no phase change material; a composition with non- microencapsulated paraffin wax, Parafol^® 18-97 as the phase change material; and a composition with microencapsulated wax, Nextek™ 24D as the phase change material. The Parafol^® 18-97 had a Differential Scanning Calorimetry (DSC) onset at 26.9° C, a latent heat from 0-40° C of > 220 Joules/gram and no particle size. The Nextek™ 24D had a DSC onset at 24° C, a latent heat from 0-40° C of 150-160 Joules/gram and a particle size of from 14-24 microns. The compositions used DM Lite 300, an olefin based thermoplastic hot melt adhesive from Henkel Corporation which has no particle size and negligible latent heat from 0-40° C, as the resin. Properties are shown below in TABLE 1. The compositions were prepared using the following procedure: the adhesive (DM Lite 300) was melted in a metal can at l50°C then the PCM (Parafol^® 18-97 or Nextek™ 24D) was slowly added into the can, meanwhile a mechanical agitator running at 10-30 rpm was employed to promote the mixing. Mixing lasted about 1.5 hours or until the composition became homogeneous.

[00085] Upon observation it appeared that the non-encapsulated paraffin wax Parafol^® 18-97 tended to merge into the adhesive matrix of the hot melt adhesive while the microencapsulated wax, Nextek™ 24D, remained as discrete particles in the adhesive matrix. In addition, the data shows that inclusion of Parafol^® 18-97 made hot melt adhesive softer, weaker and less viscous compared to the control DM Lite 300. By way of contrast the microencapsulated Nextek™ 24D greatly enhanced the firmness, strength and viscosity of the hot melt adhesive compared to the control DM lite 300. The microencapsulated wax acted like a filler would to enhance these properties. These experiments show the advantage of adding a microencapsulated wax versus adding a non-encapsulated wax to the composition.

Example 2

[00086] Another series of compositions were prepared comprising the microencapsulated phase change material Nextek™ 24D was combined at a series of weight percentages with DM COOL 110 as the resin. Various properties of the compositions were measured. DM COOL 110 is a rubber- based adhesive from Henkel Corporation that has a negligible latent heat from 0-40° C and no particle size. Figure 1 shows the specific heat capacity (Cp) traces for the series of composition: DM COOL 110 adhesive alone, solid line with no symbols; 90% DM COOL 110 adhesive + 10% Nextek™ 24 D, dotted line with filled circles; 70% DM COOL 110 adhesive + 30% Nextek™ 24 D, dashed lines with dots and filled triangles; and 50% DM COOL 110 adhesive + 50% Nextek™ 24 D, line with long dash two short dashes and filled squares. The addition of the microencapsulated wax according to the present disclosure caused the specific heat capacity Cp of the adhesive composition to increase dramatically and the compositions also display a dual peak distribution. Data for these compositions is shown below in TABLE 2.

[00087] The data in TABLE 2 shows that as one increases the amount of microencapsulated wax phase change material in the hot melt adhesive composition one improves and increases the storage modulus at both 25 and 40° C, the viscosity and the heat of enthalpy. There is a reduction in the adhesive strength with increasing amounts of the microencapsulated wax, especially if one goes to 50%, however even at 30% microencapsulated wax the hot melt adhesive retains significant adhesive strength.

[00088] Figures 2, 3 and 4 show Scanning Electron Micrograph (SEM) photographs of films made from compositions 3, 4 and 5 containing 10%, 30% and 50% respectively of Nextek™ 24D on a substrate at 150X magnification. Example 3

[00089] Another series of compositions comprising DM Lite 300 as the resin and a series of levels of Nextek™ 24D were prepared according to the above procedures. Properties for these compositions are shown below in TABLE 3.

[00090] The data show that addition of the microencapsulated phase change material increases the composition storage modulus at 25 and 40° C, the viscosity and the enthalpy of the hot melt adhesive.

Example 4

[00091] Another series of hot melt adhesive compositions comprising EVA based adhesive (EVA-1) as the resin and a series of levels of microencapsulated phase change material Nextek™ 24D were prepared. EVA-1 is a 1 : 1 melt blend of Ateva 3342 AC (VA content, 33% from Celanese Corporation) and Escorez 5690 (Softening pint 90°C, from Exxon Mobile). Properties for these compositions are shown below in TABLE 4.

[00092] The data show that addition of the microencapsulated phase change material increases the storage modulus at 25 and 40° C, the viscosity and the enthalpy of the hot melt adhesive.

Example 5

[00093] Another series of hot melt adhesive compositions comprising a polyurethane (PU) prepolymer as the resin and a series of levels of Nextek™ 24D were prepared. Properties for these compositions are shown below in TABLE 6.

[00094] The PU hot melt adhesive was prepared using the components at the levels shown in Tables 5 and 6 below. The polyurethane (PU) hot melt adhesive was prepared as follows. The non-isocyanate components were combined and melted at 132° C (270° F). Then Nextek™ 24D used was added slowly with stirring. Next the mixture was dried under vacuum for 2 hours. Then the MDI was added and reacted for 1.5 hours. Finally, the DMDEE catalyst was added followed by stirring for 20 minutes.

1 a mil is 0.001 inches.

[00095] Figures 5 to 11 show surface and cross-sectional SEM photographs of the adhesives in TABLE 6 in film form. Specifically, Figure 5 is a surface view of comparative composition E, the 100 % PU hot melt adhesive, on the substrate at a 15 OX magnification. Figure 6 is a surface view of composition 12, the 90 % PU hot melt adhesive plus 10% Nextek™ 24D, on the substrate at a 150X magnification. Figure 7 is a cross-sectional view of composition 12, the 90 % PU hot melt adhesive plus 10% Nextek™ 24D, on the substrate at an 85X magnification showing distribution of the PCM particles in the adhesive. Figure 8 is a surface view of composition 13, the 70 % PU hot melt adhesive plus 30% Nextek™ 24D, on the substrate at a 150X magnification. Figure 9 is a cross-sectional view of composition 13, the 70 % PU hot melt adhesive plus 30% Nextek™ 24D, on the substrate at an 85X magnification. Figure 10 is a surface view of composition 14, the 50 % PU hot melt adhesive plus 50% Nextek™ 24D, on the substrate at a 150X magnification. Figure 11 is a cross- sectional view of composition 14, the 50 % PU hot melt adhesive plus 50% Nextek™ 24D, on the substrate at an 85X magnification.

[00096] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

[00097] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well- known technologies are not described in detail.

Claims

We claim:

1. A hot melt adhesive composition comprising:

1 to 99 % by weight of a resin, based on a total weight of the composition; and 1 to 65 % by weight of a phase change material, based on the total weight of the composition, the phase change material having a melting temperature of from 5 to 80° C and a latent heat of fusion of from 40 to 300 Joules/ gram.

2. The hot melt adhesive of claim 1, having a storage modulus (G’25) at 25° C of from about 1X10³ to about 1X10⁸ Pascal, a storage modulus (G’40) at 40° C of from about 1X10² to about 1X10⁷ Pascal and a viscosity at 160° C of less than 100,000 centipoise.

3. The hot melt adhesive composition of claim 1 or 2, having a storage modulus (G’25) at 25° C of from about 1X10⁴ to about 1X10⁷ Pascal, a storage modulus (G’40) at 40° C of from about 1X10³ to about 1X10⁶ Pascal and a viscosity at 160° C of less than 100,000 centipoise.

4. The hot melt adhesive of any of claims 1 to 3, wherein said composition having a viscosity at 160° C of from 500 to 100,000 centipoise.

5. The hot melt adhesive of any of claims 1 to 4, wherein said composition having a viscosity at 160° C of from 1,000 to 40,000 centipoise.

6. The hot melt adhesive composition of any of claims 1 to 5, wherein said phase change material is a microencapsulated organic wax comprising an organic wax at least partially surrounded by a non-reactive shell.

7. The hot melt adhesive composition of any of claims 1 to 6, wherein said wherein said phase change material is a microencapsulated organic wax having an average particle size of from 2 to 30 microns in diameter.

8. The hot melt adhesive composition of any of claims 1 to 7, wherein said phase change material is a microencapsulated organic wax having a melting temperature of from 10 to 50°

C.

9. The hot melt adhesive composition of any of claims 1 to 8, wherein said phase change material has a latent heat of fusion of from 100 to 200 Joules/gram.

10. The hot melt adhesive composition of any of claims 1 to 9, being a reactive hot melt adhesive.

11. The hot melt adhesive composition of any of claims 1 to 10, being a reactive hot melt adhesive wherein said resin comprises an isocyanate functional polyurethane prepolymer.

12. The hot melt adhesive composition of any of claims 1 to 11, being a thermoplastic hot melt adhesive wherein said resin comprises an olefin derived component.

13. The hot melt adhesive composition of any of claims 1 to 12, wherein said resin comprises a homopolymer or a copolymer formed from one or more C₂ to Cio olefin monomers.

14. The hot melt adhesive composition of any of claims 1 to 13, wherein said resin comprises a poly ethylene vinyl acetate copolymer.

15. The hot melt adhesive composition of any of claims 1 to 14, wherein said resin comprises a poly ethylene n-butyl acrylate.

16. The hot melt adhesive composition of any of claims 1 to 15, wherein said resin comprises a rubber derived component.

17. The hot melt adhesive composition of any of claims 1 to 16, wherein said resin comprises one or more rubbers selected from the group consisting of styrene-isoprene-styrene (SIS) rubbers, styrene-butadiene-styrene (SBS) rubbers, styrene-ethylene-butadiene-styrene (SEBS) rubbers, styrene-ethylene-isoprene-styrene (SEIS) rubbers, and mixtures thereof.

18. The hot melt adhesive composition of any of claims 1 to 17, further comprising one or more additives selected from the group consisting of tackifiers, an acrylic polymer, a methacrylic polymer, a catalyst, a moisture scavenger, an adhesion promotor, a filler, a plasticizer, a defoamer, a rheology modifier, an air release agent, a flame retardant, and mixtures thereof.