Moisture-curable polyurethane hot melt adhesive composition

Abstract

Provided is a moisture-curable polyurethane hot melt adhesive composition comprising at least one polyurethane prepolymer obtained by reacting a component comprising (A) a polyol mixture, the component comprising (a) at least one polyol that is liquid at room temperature, (b) at least one crystalline polyester polyol having a melting point of less than 70°C, and (c) 0 to less than 15.4 wt %, based on the total amount of the composition, of at least one crystalline polyester polyol having a melting point of 70°C or higher, with (B) at least one polyisocyanate having at least two isocyanate groups per molecule.

Description

[Technical Field]

[0001] Technical Field The present invention relates to a moisture-curable polyurethane hot melt adhesive composition, in particular a moisture-curable polyurethane hot melt adhesive composition that exhibits excellent fluidity and adhesive strength upon curing, as well as to a method for preparing and using the same. [Background technology]

[0002] Background of the Invention In the electronics field, the use of silicone formulations or two-part polyurethane adhesives to fill gaps between substrates is commonly known in the art as a "fluid sealant." However, these fluid sealants lack high initial adhesive strength, resulting in significant delays in production.

[0003] Moisture-curable polyurethane hot melt adhesive compositions are solid at room temperature and melt into a viscous liquid when heated to a moderate temperature. They are then applied to and bonded to a substrate. The molten adhesive composition then cools and solidifies, forming an initial bond to the substrate. It can then react with moisture to form a crosslinked structure, achieving high final strength. Moisture-curable polyurethane hot melt adhesive compositions are environmentally friendly, cure quickly, and have high adhesive strength, making them suitable for bonding a variety of substrate materials in electronic devices, including polycarbonate (PC), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), metals, and inorganic glass. However, moisture-curable polyurethane hot melt adhesive compositions used to fill gaps in electronic devices require excellent adhesive flowability without sacrificing other properties, such as adhesion, cure time, and impact resistance.

[0004] Most of the prior art has focused on improving dispensing equipment technology to address this issue, with very little dedicated to developing adhesive compositions. For example, CN 101418203 A discloses that chain extenders and fillers can significantly improve the viscosity of adhesives. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Chinese Patent Application Publication No. 101418203 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, there remains a need to develop moisture-curable polyurethane hot melt adhesive compositions that exhibit excellent flowability on substrates to achieve gap-filling objectives without adversely affecting other important properties such as adhesive strength. [Means for solving the problem]

[0007] Summary of the Invention As a result of intensive research, the inventors have found that the above problems can be solved by: (a) at least one polyol that is liquid at room temperature; (b) at least one crystalline polyester polyol having a melting point below 70°C; and (c) 0 to less than 15.4 wt. % of at least one crystalline polyester polyol having a melting point of 70° C. or higher, based on the total weight of the composition (A) a component containing a polyol mixture, (B) at least one polyisocyanate having at least two isocyanate groups per molecule; The present inventors have found that this problem can be solved by providing a moisture-curable polyurethane hot melt adhesive composition comprising at least one polyurethane prepolymer obtained by reacting a

[0008] In another embodiment of the present invention, a method for preparing the moisture-curable polyurethane hot melt adhesive composition of the present invention is provided.

[0009] In another embodiment of the present invention, there is provided a laminate comprising a first substrate, a second substrate, and an adhesive layer sandwiched therebetween, wherein the first substrate and the second substrate are independently selected from glass, resin, metal, and polyolefin, and the adhesive layer is formed by curing the adhesive composition of the present invention.

[0010] In another embodiment of the present invention, an electronic device is provided comprising an article of the present invention.

[0011] In another embodiment of the present invention, there is provided the use of the adhesive compositions and laminates of the present invention in touch screens, mobile phones, liquid crystal displays, polymer panels, films, conductive layers, protective layers or ink layers.

[0012] The present invention features a moisture-curable polyurethane hot melt adhesive composition that has excellent flowability on various substrates and good adhesive strength upon curing. DETAILED DESCRIPTION OF THE INVENTION

[0013] Detailed Description of the Invention It should be understood by those skilled in the art that the present invention is merely a description of exemplary embodiments and is not intended to limit the broader embodiments of the present invention. Each embodiment so described can be combined with other embodiments unless expressly stated to the contrary. In particular, any feature indicated as being preferred or advantageous can be combined with any other feature indicated as being preferred or advantageous.

[0014] Unless otherwise specified, terms used in the context of the present invention should be construed according to the definitions below.

[0015] Unless otherwise specified, as used herein, the terms "a," "an," and "the" include both singular and plural referents.

[0016] As used herein, the terms "comprise" and "including" are synonymous with "include," "includes," or "contains," and are inclusive or open-ended and do not exclude additional, unrecited elements, components, or process steps.

[0017] Unless otherwise specified, the recitation of numerical endpoints includes all numbers and fractions subsumed within the respective ranges, as well as the recited endpoints.

[0018] Molecular weights refer to number average molecular weights (Mn) unless otherwise specified. All molecular weight data refer to values ​​obtained by gel permeation chromatography (GPC) in accordance with DIN 55672 unless otherwise specified.

[0019] All references cited herein are incorporated by reference in their entirety.

[0020] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs.

[0021] The present invention provides (a) at least one polyol that is liquid at room temperature; (b) at least one crystalline polyester polyol having a melting point below 70°C; and (c) 0 to less than 15.4 wt. % of at least one crystalline polyester polyol having a melting point of 70° C. or higher, based on the total weight of the composition (A) a component containing a polyol mixture, (B) at least one polyisocyanate having at least two isocyanate groups per molecule; and a moisture-curable polyurethane hot melt adhesive composition comprising at least one polyurethane prepolymer obtained by reacting a

[0022] Polyurethane Prepolymer The moisture-curable polyurethane hot melt adhesive composition comprises at least one polyurethane prepolymer obtained by reacting components including a polyol mixture with at least one polyisocyanate having at least two isocyanate groups per molecule.

[0023] In one embodiment, the amount of isocyanate-functional polyurethane prepolymer in the present invention is 60 to 99.9 wt %, preferably 65 to 95 wt %, based on the total weight of the adhesive composition.

[0024] In some embodiments, the polyurethane prepolymers of the present invention have an NCO content of from 1.3% to 6% by weight.

[0025] In another embodiment, the polyurethane prepolymer has a number average molecular weight of 5,000 to 30,000 g / mol, preferably 8,000 to 15,000 g / mol, and more preferably 8,500 to 10,000 g / mol.

[0026] (A) Polyol mixture According to the present invention, the polyol mixture (A) contains (a) at least one polyol that is liquid at room temperature, (b) at least one crystalline polyester polyol having a melting point of less than 70°C, and (c) 0 to less than 15.4 wt % of at least one crystalline polyester polyol having a melting point of 70°C or higher, based on the total amount of the composition.

[0027] (a) Liquid polyol According to the invention, the polyol mixture used in the invention comprises at least one polyol that is liquid at room temperature, which liquid polyol can provide flow properties to the adhesive composition.

[0028] Therefore, the liquid polyol has a glass transition temperature (Tg) of 0° C. or lower, preferably −100° C. to 0° C., and more preferably −50° C. to 0° C. If the Tg of the liquid polyol is too high, it is difficult to become liquid.

[0029] In some embodiments, the at least one polyol that is liquid at room temperature may be selected from a liquid polyester polyol and / or a liquid polyether polyol.

[0030] Examples of liquid polyester polyols can be obtained by ring-opening polymerization of lactones such as ε-caprolactone and / or can be derived from diols and diacids. Examples of diols useful for preparing preferred polyester polyols include ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and mixtures thereof. Examples of diacids useful for preparing preferred polyester polyols include succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, dimer acid, and mixtures thereof. Included within the scope of useful diacids are various diacid derivatives, such as carboxylate esters (especially methyl and ethyl esters), acid halides (such as acid chlorides), and acid anhydrides, as well as mixtures thereof.

[0031] Specific examples of suitable liquid polyester polyols include poly(hexanediol adipate) polyol, poly(butanediol adipate) polyol, poly-ε-caprolactone polyol, poly(hexanediol decanedioate) polyol, poly(hexanediol adipate terephthalate) polyol, and mixtures thereof.

[0032] Alternatively, liquid polyether polyols can be used in the present invention. Compared to liquid polyester polyols, the use of liquid polyether polyols in the composition increases the adhesive strength of the cured adhesive composition. These liquid polyether polyols can be obtained by copolymerizing at least one compound, such as ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran, with at least one compound having an average of at least two active hydrogen atoms per molecule, such as the polyhydric alcohols listed above, including ethylene glycol, propylene glycol, dipropylene glycol, glycerol, and mixtures thereof. Other suitable polyhydric compounds include sucrose, ethylenediamine, propylenediamine, triethanolamine, 1,2-propanedithiol, and mixtures thereof.

[0033] Preferred liquid polyether polyols may be polypropanediol, polytetramethylene ether glycol, poly(oxypropylene) glycol, polyethylene oxide, polybutylene oxide, and ethylene oxide end-capped with any of the foregoing. The most preferred polyether polyols are polytetramethylene ether glycol, poly(oxypropylene) glycol, and ethylene oxide end-capped poly(oxypropylene) glycol.

[0034] In a preferred embodiment, the liquid polyol has a number average molecular weight of 400 to 8,000 g / mol, preferably 500 to 5,000 g / mol, more preferably 1,000 to 4,000 g / mol.

[0035] The liquids which are polyols at room temperature can be used alone or in combination of at least two different liquid polyols.

[0036] Commercially available products may also be used in the present invention. Suitable commercially available liquid polyether polyols include Voranol™ 2104, 2110, 2120, and 2140 available from Dow Chemical Company. Suitable commercially available liquid polyester polyols are sold under the trade name DYNACOLL 7200 series by Evonik Industries AG (Germany), including DYNACOLL 7210, 7230, 7231, 7250, and 7255.

[0037] Particularly preferably, component (a) can be incorporated in an amount of greater than 0 to 60% by weight, preferably 10 to 60% by weight, more preferably 15 to 50% by weight, based on the total weight of the composition.

[0038] (b) a crystalline polyester polyol having a melting point of less than 70°C According to the invention, the polyol mixture used in the invention comprises at least one crystalline polyester polyol (b) having a melting point below 70°C.

[0039] As used herein, the "melting point" is determined by a melting curve obtained by differential scanning calorimetry (DSC) method.

[0040] In a preferred embodiment, component (b) comprises at least one crystalline polyester polyol having a melting point of less than 60° C., more preferably from 40° C. to 55° C. In a particularly preferred embodiment, component (b) comprises at least two crystalline polyester polyols having different melting points within the above range.

[0041] In a preferred embodiment, component (b) has a number average molecular weight of 1,000 to 20,000 g / mol, preferably 2,000 to 15,000 g / mol, more preferably 2,000 to 8,000 g / mol.

[0042] Examples of such crystalline polyester polyols having a melting point below 70°C can be obtained by ring-opening polymerization of lactones such as ε-caprolactone and / or can be derived from diols and diacids. Examples of diols useful for preparing preferred polyester polyols include ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and mixtures thereof. Examples of diacids useful for preparing preferred polyester polyols include succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and 1,12-dodecanedioic acid, dimer acid, and mixtures thereof. Included within the scope of useful diacids are various diacid derivatives, such as carboxylate esters (especially methyl and ethyl esters), acid halides (such as acid chlorides), and acid anhydrides, as well as mixtures thereof.

[0043] In a preferred embodiment, component (b) comprises at least one crystalline polycaprolactone polyol having a melting point below 70°C. The polycaprolactone polyol is a polyester polyol produced by ring-opening polymerization of ε-caprolactone with a polyol initiator or a polyamine initiator. Examples of usable polyol initiators include diols such as ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,6-hexanediol, neopentyl glycol, bisphenol A, and resorcinol; triols such as glycerin, 1,2,6-hexanetriol, and 1,1,1-tris(hydroxymethyl)propane; tetraols such as pentaerythritol, erythritol, and methyl glucoside; hexaols such as sorbitol and dipentaerythritol; and octanols such as sucrose. Usable polyamine initiators include, for example, diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, and hydrazine, and at least trifunctional polyamines such as diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. These initiators may be used alone or in combination of two or more. Of these initiators, diols and diamines are preferably used.

[0044] Specific examples of suitable crystalline polyester polyols having a melting point below 70°C include poly(hexanediol adipate) polyol, poly(butanediol adipate) polyol, poly-epsilon-caprolactone polyol, poly(dodecanedioic acid hexanediol) polyol, poly(hexanediol adipate terephthalate) polyol, polycaprolactone polyol, and mixtures thereof.

[0045] Suitable commercially available crystalline polyester polyols having a melting point below 70°C include those sold by Evonik Industries AG (Germany) under the DYNACOLL 7300 series tradenames, such as DYNACOLL 7360, 7361, 7362, 7363, 7365, 7381, and those sold by Ingevity under the CAPA™ series tradenames, such as CAPA™ 2201, 2205, 2209, 2302, 2303. Suitable commercially available crystalline polycaprolactone polyols having a melting point below 70°C for use as component (b) are Daicel's 205, 208, 210, and 210CP.

[0046] Particularly preferably, component (b) can be incorporated in an amount of 0% to 80% by weight, preferably 10% to 80% by weight, more preferably 15% to 60% by weight, based on the total weight of the composition.

[0047] (c) a crystalline polyester polyol having a melting point of 70°C or higher According to the present invention, the polyol mixture used in the present invention contains 0 to less than 15.4 wt % of at least one crystalline polyester polyol having a melting point of 70° C. or higher, based on the total amount of the composition.

[0048] In a preferred embodiment, the polyol mixture does not contain a crystalline polyester polyol (c) having a melting point of 70° C. or higher. In another embodiment, the crystalline polyester polyol must be present in an amount of 0 to less than 15.4 wt %, preferably 0 to less than 12 wt %, more preferably 0 to less than 11 wt %, and even more preferably 0 to less than 5 wt %, based on the total amount of the composition; otherwise, the flowability of the adhesive composition will be dramatically reduced.

[0049] In a preferred embodiment, a crystalline polyester polyol having a melting point of 70° C. or higher and 120° C. or lower is used as component (c) of the present invention.

[0050] Specific examples of suitable crystalline polyester polyols having a melting point of 70° C. or higher include poly(hexanediol dodecanedioate) polyol, poly(butanediol dodecanedioate) polyol, and mixtures thereof.

[0051] Suitable commercially available crystalline polyester polyols with melting points above 70° C. are DYNACOLL 7380, 7330, and 7340 from Evonik Industries AG (Germany).

[0052] (B) Polyisocyanate The moisture-curable polyurethane hot melt adhesive composition comprises at least one polyurethane prepolymer obtained by reacting (A) the polyol mixture of the present invention with (B) at least one polyisocyanate having at least two isocyanate groups per molecule.

[0053] In a preferred embodiment, the ratio of component (A) to component (B) is selected so that the molar ratio of NCO to OH is 1.3 to 4.0.

[0054] Useful polyisocyanates include any suitable isocyanate having at least two isocyanate groups per molecule, including, for example, aliphatic, cycloaliphatic, araliphatic, arylalkyl, and aromatic isocyanates, and mixtures thereof.

[0055] Preferred polyisocyanates include 4,4-diphenylmethane diisocyanate (MDI), hydrogenated MDI (H12MDI), partially hydrogenated MDI (H6MDI), xylene diisocyanate (XDI), tetramethylxylene diisocyanate (TMXDI), 4,4-diphenyldimethylmethane diisocyanate, dialkylenediphenylmethane diisocyanate, tetraalkylenediphenylmethane diisocyanate, 4,4-diphenyl Isomers of toluylene diisocyanate (TDI), 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1-methyl-2,4-diisocyanatocyclohexane, 1,6-diisocyanato-2,2,4-trimethylhexane, 1,6-diisocyanato-2,4,4-trimethylhexane, 1-isocyanatomethyl-3-isocyanato-1,5,5-trimethylcyclohexane (IPDI) , tetramethoxybutane-1,4-diisocyanate, naphthalene-1,5-diisocyanate (NDI), butane-1,4-diisocyanate, hexane-1,6-diisocyanate (HDI), dicyclohexylmethane diisocyanate, 2,2,4-trimethylhexane-2,3,3-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, ethylene diisocyanate, methylenetriphenyl The polyisocyanate may be selected from methyl triisocyanate (MIT), phthalic acid bisisocyanatoethyl ester, trimethylhexamethylene diisocyanate, 1,4-diisocyanatobutane, 1,12-diisocyanatododecane, dimeric fatty acid diisocyanate, lysine ester diisocyanate, 4,4-dicyclohexylmethane diisocyanate, 1,3-cyclohexane or 1,4-cyclohexane diisocyanate, and mixtures thereof. The most preferred polyisocyanate is 4,4-diphenylmethane diisocyanate (MDI) and its isomers, chain-extended MDI, and mixtures thereof.

[0056] Useful commercially available polyisocyanates include MONDUR ML® manufactured by Covestro, ISONATE™ 50 OP and ISONATE™ 125M manufactured by Dow Chemical Company, and Desmodur® 44C available from Covestro Polymers (China) Co., Ltd.

[0057] Particularly preferably, component (B) can be incorporated into the adhesive composition in an amount of 5% to 50% by weight, preferably 10% to 35% by weight, and more preferably 10% to 30% by weight, based on the total weight of the composition.

[0058] thermoplastic resin To impart high strength to the adhesive composition, the adhesive composition of the present invention optionally further comprises at least one thermoplastic resin.

[0059] For purposes of this invention, thermoplastic resins are distinguished from thermosetting resins, which solidify through crosslinking or curing upon exposure to heat and / or an appropriate curing agent. Thermoplastic resins as described herein include non-reactive thermoplastic resins, preferably essentially free of unreacted monomeric isocyanates.

[0060] Suitable thermoplastic resins may be selected from polyesters, phenoxy resins, phenolic resins, acrylic polymers, acrylic block copolymers, acrylic polymers with tertiary alkylamide functionality, polysiloxane polymers, polystyrene copolymers, polyvinyl polymers, divinylbenzene copolymers, polyetheramides, polyvinyl acetal, polyvinyl butyral, polyvinyl acetol, polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride, methylene polyvinyl ether, cellulose acetate, styrene acrylonitrile, amorphous polyolefins, thermoplastic urethanes, polyacrylonitrile, ethylene vinyl acetate copolymers, ethylene vinyl acetate terpolymers, functionalized ethylene vinyl acetate, ethylene acrylate copolymers, ethylene acrylate terpolymers, ethylene butadiene copolymers and / or block copolymers, styrene butadiene block copolymers, polycaprolactone, and mixtures thereof.

[0061] In a preferred embodiment, the thermoplastic resin has a number average molecular weight of 8,000 to 100,000 g / mol, preferably 8,000 to 80,000 g / mol, more preferably 20,000 to 50,000 g / mol.

[0062] Particularly preferably, the thermoplastic resin is present in the adhesive composition in an amount of 0% to 40% by weight, preferably 5% to 30% by weight, based on the total weight of the composition.

[0063] Other ingredients Other additives may be added to the adhesive composition, such as those commonly used in the art, such as colorants, antioxidants, etc.

[0064] Examples of colorants include metal oxide pigments, titanium dioxide, optionally surface-treated pigments which may be selected from zirconium oxide or cerium oxide, zinc oxide, iron oxide (black, yellow or red), chromium oxide, manganese.

[0065] Examples of antioxidants include phenolic antioxidants such as BHT (butylated hydroxytoluene), octadecyl-3,5-bis(1,1-dimethyl)-4-hydroxybenzenepropanoate, and pyrogallol; phosphite antioxidants such as triphenyl phosphite and tris(nonylphenyl) phosphite; and thioester antioxidants such as dilauryl thiodipropionate.

[0066] adhesive composition In a preferred embodiment, the present invention provides a composition comprising, based on the total weight of the composition: greater than 0% to 60%, preferably 10% to 60%, and more preferably 15% to 50% by weight of at least one polyol that is liquid at room temperature; from greater than 0% to 80%, preferably from 10% to 80%, and more preferably from 15% to 60%, by weight of at least one crystalline polyester polyol having a melting point below 70°C; 0% to less than 15.4% by weight, preferably 0 to less than 12% by weight, more preferably 0 to less than 11% by weight, and even more preferably 0 to less than 5% by weight of at least one crystalline polyester polyol having a melting point of 70°C or less; and 5% by weight to 50% by weight, preferably 10% by weight to 35% by weight, more preferably 10% by weight to 30% by weight of at least one polyisocyanate having at least two isocyanate groups in one molecule; The present invention provides a moisture-curable polyurethane hot melt adhesive composition comprising:

[0067] A method for preparing a moisture-curable polyurethane hot melt adhesive composition comprises the following steps: (i) mixing the polyol and thermoplastic resin (if present) at a temperature of 110-160°C, followed by vacuuming; (ii) a step of lowering the reaction temperature, adding a polyisocyanate having at least two isocyanate groups per molecule at a temperature of 70 to 130°C, and then controlling the temperature at 90 to 130°C; (iii) adding optional additives and mixing uniformly; and (iv) Discharging the mixture at a temperature of 90 to 150°C, preferably under nitrogen protection. Includes.

[0068] The equipment used for mixing, stirring, dispersing, etc. is not particularly limited. An automatic mortar equipped with a stirrer or heater, a Henschel mixer, a three-roll mill, a ball mill, a planetary mixer, a bead mill, etc. can be used. These equipment can also be used in appropriate combination. The method for preparing the curable composition is not particularly limited, as long as a composition in which the above components are uniformly mixed can be obtained.

[0069] The moisture-curable polyurethane hot melt adhesive composition of the present invention can be thermosetting, and cures at a temperature preferably of 100°C or less, more preferably 80°C or less.

[0070] The moisture-curable polyurethane hot melt adhesive compositions of the present invention can be readily manufactured using otherwise conventional manufacturing techniques.

[0071] Laminates, electronic devices and uses thereof In another embodiment of the present invention, there is provided a laminate comprising a first substrate, a second substrate, and an adhesive layer sandwiched therebetween, wherein the first substrate and the second substrate are independently selected from glass, resin, metal, and polyolefin, and the adhesive layer is formed by curing the adhesive composition of the present invention.

[0072] The first substrate and / or the second substrate can be a single material and a single layer, or can include multiple layers of the same or different materials. The layers can be continuous or discontinuous.

[0073] The substrate of the articles described herein can have a variety of properties, including rigidity (e.g., a stiff substrate, i.e., the substrate cannot be bent using both hands or breaks when an attempt is made to bend it using both hands), flexibility (e.g., a flexible substrate, i.e., the substrate can be bent using only the strength of both hands), porosity, electrical conductivity, lack of electrical conductivity, and combinations thereof.

[0074] The substrate of the article can be in a variety of forms including, for example, fibers, threads, yarns, woven fabrics, nonwoven fabrics, films (e.g., polymeric films, metallized polymeric films, continuous films, discontinuous films, and combinations thereof), foils (e.g., metal foils), sheets (e.g., metal sheets, polymeric sheets, continuous sheets, discontinuous sheets, and combinations thereof), and combinations thereof.

[0075] Useful substrate materials for use in the present invention include, for example, polymers (e.g., polycarbonate, ABS resin (acrylonitrile-butadiene-styrene resin), liquid crystal polymers, polyolefins (e.g., polypropylene, polyethylene, low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, and oriented polypropylene, copolymers of polyolefins with other comonomers, etc.), polyether terephthalate, ethylene-vinyl acetate, ethylene-methacrylic acid ionomer, ethylene-vinyl alcohol, polyesters such as polyethylene terephthalate, polycarbonate, polyamides such as nylon-6 and nylon-6,6, polyvinyl chloride, and polyvinylidene chloride. , cellulose-based, polystyrene and epoxy, etc.), polymer composites (e.g., composites of polymer and metal, cellulose, glass, polymer, and combinations thereof), metals (aluminum, copper, zinc, lead, gold, silver, platinum, magnesium, and metal alloys such as steel (e.g., stainless steel), tin, brass, alloys of magnesium and aluminum, etc.), carbon fiber composites, other fiber-based composites, graphene, fillers, glass (e.g., alkali aluminosilicate glass, borosilicate glass), quartz, boron nitride, gallium nitride, sapphire, silicon, carbide, ceramic, and combinations thereof, preferably liquid crystal polymers, glass, and combinations thereof.

[0076] The curable composition can be applied to a substrate using any suitable application method, including, for example, automated fine line coating, jet coating, slot die coating, roll coating, gravure coating, transfer coating, pattern coating, screen coating, spray coating, filament coating, extrusion, air knife, trailing blade, brush coating, dipping, doctor blade, offset gravure coating, rotogravure coating, and combinations thereof. The curable composition can be applied as a continuous or discontinuous coating, in single or multiple layers, and combinations thereof.

[0077] Optionally, the surface of the substrate to which the curable adhesive composition is applied is treated to enhance adhesion using any suitable method for enhancing adhesion to the substrate surface, including, for example, corona treatment, chemical treatment (e.g., chemical etching), flaming, abrasion, and combinations thereof.

[0078] In an additional embodiment of the present invention, an electronic device is provided that includes an article of the present invention.

[0079] Exemplary electronic devices include computers and computer equipment, such as telecommunications and data communications devices, such as 5G stations; printers, fax machines, scanners, keyboards, and the like; medical sensors; automotive sensors, and the like; wearable electronic devices (e.g., watches, eyeglasses), handheld electronic devices (e.g., phones (such as cell phones and smartphones), cameras, tablets, e-readers, monitors (e.g., monitors used in hospitals, medical professionals, athletes, individuals, etc.), watches, calculators, mice, touchpads, and joysticks), computers (e.g., desktop and laptop computers), computer monitors, televisions, media players, home appliances (e.g., refrigerators, washers, dryers, ovens, and microwaves), light bulbs (incandescent, light emitting diode, fluorescent, etc.), and articles containing visible, transparent or transparent components, glass housing structures, protective transparent covers for displays or other optical components.

[0080] Yet another embodiment of the present invention relates to the use of the adhesive composition in touch screens, mobile phones, liquid crystal displays, polymer panels, films, conductive layers, protective layers or ink layers. [Example]

[0081] Example The following examples are intended to assist those skilled in the art in better understanding and practicing the present invention. The scope of the present invention is not limited by the examples, but is defined in the appended claims. Unless otherwise specified, all parts and percentages are by weight.

[0082] Raw materials: Voranol™ 2120 is a polyether polyol that is liquid at room temperature and is available from Dow Chemical Company. XCP-244 is a polyester polyol that is liquid at room temperature and is available from Xuchuan Chemical Company. Priplast 3172 is a solid polyester polyol with a melting point of 40°C and is available from Croda. Dynacoll 7360 is a solid polyester polyol with a melting point of 55°C and is available from Evonik Industries AG. Dynacoll 7380 is a solid polyester polyol with a melting point of 70° C. and is available from Evonik Industries AG. Capa™ 2302 is a solid polycaprolactone polyol with a melting point of 50° C., available from Ingevity. DESMODUR 44 C FUSED is an MDI and is available from Covestro.

[0083] Test Method Horizontal flow test Sample preparation: A 101.6 mm x 25.4 mm x 1 mm polycarbonate substrate containing 20% ​​glass fiber by weight was cleaned with isopropanol and left at ambient conditions for several minutes to ensure the surface was completely dry. The sample composition was then heated to 110 °C and held for at least 20 minutes. The molten sample composition was then dispensed onto the substrate using a needle under 3 bar air pressure. The width of the original adhesive composition was controlled to approximately 1 mm, with a gap between the substrate and the needle of approximately 0.4-0.5 mm. Thirty seconds after dispensing, the width of the adhesive bead was measured and recorded as W1. After 30 minutes, when the composition had completely cured, the width of the cured adhesive was recorded as W2.

[0084] The horizontal liquidity ratio was calculated based on the following formula: Horizontal liquidity ratio = (W2-W1) / W1*100%.

[0085] The horizontal flowability of the adhesive composition was considered to be within the acceptable range if the horizontal flowability ratio was 10% or more, preferably greater than 15%, and more preferably greater than 25%.

[0086] Vertical flow test Sample preparation: A transparent polycarbonate (PC) substrate measuring 101.6 mm x 25.4 mm x 1 mm was bonded to a stainless steel (SUS) substrate measuring 101.6 mm x 25.4 mm x 1 mm to form a test specimen with a 2 mm wide gap between the PC and SUS substrates. The test specimen was positioned so that the gap was perpendicular to the horizontal plane. The adhesive composition was then heated to 110°C and held for at least 20 minutes. The molten adhesive composition was then dispensed onto the top of the gap between the PC and SUS substrates, filling the entire gap. Finally, the vertical height of the bond was measured and recorded 1 hour after dispensing.

[0087] The vertical flow of the adhesive composition was considered acceptable if the vertical height of the bond was 0.2 mm or greater, preferably 0.5 mm or greater.

[0088] Cross Tensile Strength: Sample preparation: i. First, polycarbonate substrates were prepared, measuring 101.6 x 25.4 x 1 mm and containing 20% ​​glass fiber by weight. These substrates were washed with isopropanol and left at ambient conditions for several minutes to ensure the surfaces were completely dry. The first and second substrates were placed horizontally. The overlapping areas formed a sandwiched adhesive layer between them. ii. Then, to control the thickness of the adhesive layer, two spacers with a diameter of 0.127 mm were placed on the edges of the first substrate at a distance of 3 mm from the edge of the overlapping area before spreading the adhesive composition. iii. The adhesive composition was then heated at 110°C for 30 minutes in a Loctite 400D dispenser. A 21# needle was used to dispense the adhesive composition onto the ink-glass surface. During the dispensing process, two bond lines were formed by adhesive beads dispensed through the needle. The two bond lines were applied parallel to each other, each with a distance of 1.5 to 1.8 mm from the edge of the overlapping area of ​​the two substrates. The distance between each adhesive bead was controlled to 8 mm, and the distance from the adhesive bead to the edge of the overlapping area of ​​the two substrates was also 8 mm. After dispensing, two free ends of each substrate were left, and a polycarbonate substrate containing 20% ​​by weight of glass fiber was pressed onto the substrate to form a sandwich structure of the overlapping areas. Then, a laminate was prepared. v. A 2 kg weight was applied to the sandwich structure in the overlapping area for 15 seconds. The weight was then removed and the resulting sample was placed at 23° C. and 50% relative humidity for 24 hours to allow the adhesive composition to cure.

[0089] Sample test: To measure the tensile strength at break of the adhesive layer, the cross tensile strength of the sample was measured using an Instron tensile tester at a test speed of 2 mm / min. The load at break was appropriately recorded. The adhesive composition was considered to have passed the test if the cross tensile strength was 0.5 MPa or more, preferably 1.0 MPa or more.

[0090] Examples 1 to 7 (Ex.1 to Ex.7) and Comparative Examples 1 to 2 (CEx.1 to CEx.2) Adhesives were prepared using the ingredients in the amounts (parts by weight) listed in Table 1 according to the methods described below, and the properties were tested using the methods described above. The evaluation results are shown in Table 1.

[0091] A method for preparing a moisture-curable polyurethane hot melt adhesive composition comprises the following steps: i mixing polyol at a temperature of 110-160°C, followed by vacuum; ii. Lowering the reaction temperature, adding polyisocyanate at a temperature of 80-120°C, and then controlling the temperature at 90-130°C; and iii. Discharging the mixture under nitrogen protection at a temperature of 90-150°C; Includes.

[0092] [Table 1]

[0093] As can be seen from Table 1, the moisture-curable polyurethane hot melt adhesive compositions of Examples Ex. 1 to Ex. 3 exhibited good horizontal and vertical flow properties, and maintained satisfactory tensile strength upon curing. However, when the amount of component (c) exceeds 12 wt %, the composition generally does not have the flowability required for its intended use.

[0094] [Table 2]

[0095] As can be seen from Table 2, two moisture-curable polyurethane hot melt adhesive compositions were prepared containing the same amount of component (c), one without liquid polyol (CEx.2) and the other with liquid polyol (Ex.1). The results showed that the composition adhesive lacked the necessary fluidity when component (a) was not included.

[0096] [Table 3]

[0097] As can be seen from Table 3, the moisture-curable polyurethane hot melt adhesive compositions of the present invention having polycaprolactone polyols exhibited improved lateral flow and exhibited high tensile strength upon cure.

[0098] [Table 4]

[0099] As can be seen from Table 4, the use of liquid polyether polyols in the adhesive compositions of the present invention improves the adhesive strength of the adhesive composition upon cure, compared to liquid polyester polyols.

[0100] While certain preferred embodiments have been described, many modifications and variations are possible in light of the above teachings. It is therefore understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.

Claims

1. (a) at least one polyol that is liquid at room temperature; (b) at least one crystalline polyester polyol having a melting point below 70°C; and (c) 0 to less than 15.4 wt. %, based on the total weight of the composition, of at least one crystalline polyester polyol having a melting point of 70° C. or higher. (A) a component comprising a polyol mixture, (B) at least one polyisocyanate having at least two isocyanate groups per molecule; 1. A moisture-curable polyurethane hot melt adhesive composition comprising at least one polyurethane prepolymer obtained by reacting a

2. 2. The composition of claim 1, wherein component (a) has a number average molecular weight of 400 to 8,000 g / mol, preferably 500 to 5,000 g / mol, more preferably 1,000 to 4,000 g / mol.

3. 10. The composition of claim 1, wherein component (b) comprises at least one crystalline polycaprolactone polyol having a melting point below 70°C.

4. 2. The composition of claim 1, wherein component (c) is present in an amount of 0 to less than 12 wt. %, more preferably 0 to less than 11 wt. %, and even more preferably 0 to less than 5 wt. %, based on the total amount of the composition.

5. Component (B) is 4,4-diphenylmethane diisocyanate (MDI), hydrogenated MDI (H12MDI), partially hydrogenated MDI (H6MDI), xylene diisocyanate (XDI), tetramethyl xylene diisocyanate (TMXDI), 4,4-diphenyldimethylmethane diisocyanate, dialkylenediphenylmethane diisocyanate, tetraalkylenediphenylmethane diisocyanate, 4,4-dibenzyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, isomers of toluylene diisocyanate (TDI), 1-methyl-2,4-diisocyanatocyclohexane, 1,6-diisocyanato-2,2,4-trimethylhexane, 1,6-diisocyanato-2,4,4-trimethylhexane, 1-isocyanatomethyl-3-isocyanato-1,5,5-trimethylcyclohexane (IPDI), tetramethoxybutane-1,4-diisocyanate, naphthalene-1,5-diisocyanate (NDI) ), butane-1,4-diisocyanate, hexane-1,6-diisocyanate (HDI), dicyclohexylmethane diisocyanate, 2,2,4-trimethylhexane-2,3,3-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, ethylene diisocyanate, methylene triphenyl triisocyanate (MIT), phthalic acid bisisocyanatoethyl ester, trimethylhexamethylene diisocyanate, 1,4-diisocyan 2. The composition of claim 1, wherein the polyisocyanate is selected from the group consisting of methyl methyl acrylate, methyl meth ...

6. The composition of claim 1, wherein the at least one polyurethane prepolymer has an NCO content of from 1.3% to 6% by weight.

7. 2. The composition of claim 1, wherein the ratio of component (A) to component (B) is selected to provide an NCO to OH molar ratio of 1.3 to 4.

0.

8. The composition of claim 1 further comprising at least one thermoplastic resin.

9. 9. The composition of claim 8, wherein the thermoplastic resin is selected from polyesters, phenoxy resins, phenolic resins, acrylic polymers, acrylic block copolymers, acrylic polymers with tertiary alkylamide functionality, polysiloxane polymers, polystyrene copolymers, polyvinyl polymers, divinylbenzene copolymers, polyetheramides, polyvinyl acetals, polyvinyl butyrals, polyvinyl acetols, polyvinyl alcohols, polyvinyl acetates, polyvinyl chloride, methylene polyvinyl ethers, cellulose acetate, styrene acrylonitrile, amorphous polyolefins, thermoplastic urethanes, polyacrylonitriles, ethylene vinyl acetate copolymers, ethylene vinyl acetate terpolymers, functionalized ethylene vinyl acetates, ethylene acrylate copolymers, ethylene acrylate terpolymers, ethylene butadiene copolymers and / or block copolymers, styrene butadiene block copolymers, polycaprolactone, and mixtures thereof.

10. 10. The composition of claim 1, wherein component (a) is present in an amount of from greater than 0 to 60 wt.%, preferably from 10 to 60 wt.%, more preferably from 15 to 50 wt.%, based on the total weight of the composition.

11. 2. The composition of claim 1, wherein component (b) is present in an amount of from greater than 0 to 80 wt.%, preferably from 10 to 80 wt.%, more preferably from 15 to 60 wt.%, based on the total weight of the composition.

12. 2. The composition of claim 1, wherein component (B) is present in an amount of 5 wt. % to 50 wt. %, preferably 10 wt. % to 35 wt. %, preferably 10 wt. % to 30 wt. %, based on the total weight of the composition.

13. (i) mixing the polyol and, if present, the thermoplastic resin at a temperature of 110-160°C, followed by vacuum; (ii) a step of lowering the reaction temperature, adding a polyisocyanate having at least two isocyanate groups in one molecule at a temperature of 70 to 130°C, and then controlling the temperature at 90 to 130°C; (iii) optionally adding additives and mixing uniformly; and (iv) discharging the mixture, preferably under nitrogen protection, at a temperature of 90-150°C; A method for preparing the hot melt adhesive composition of any of claims 1 to 12, comprising:

14. A laminate comprising a first substrate, a second substrate, and an adhesive layer sandwiched therebetween, wherein the first substrate and the second substrate are independently selected from glass, resin, metal, and polyolefin, and the adhesive layer is formed by curing the adhesive composition according to any one of claims 1 to 12.

15. An electronic device comprising the laminate of claim 14.

16. Use of the adhesive composition according to any one of claims 1 to 12 in touch screens, mobile phones, liquid crystal displays, polymer panels, films, conductive layers, protective layers or ink layers.