Adhesive composition for bonding dissimilar materials and laminate thereof

Abstract

The present invention relates to polyurethane adhesive compositions and laminates comprising one of the adhesive compositions and methods of making such laminates. The adhesive may be a two-component adhesive. The prepolymer may include an NCO prepolymer and one or more silane adhesion promoters. The curing agent component includes a second polyol. The second polyol may have a number average molecular weight of at least about 2,000 Daltons, and optionally up to at least about 80,000 Daltons, and all number average molecular weights between both. The curing agent may also include a monoether. According to application requirements, the adhesive can be a low-modulus adhesive or a high-modulus adhesive.

Description

Technical Field

[0001] The present invention relates to adhesive compositions useful for bonding dissimilar materials; laminates formed by bonding such dissimilar materials; and methods of making such laminates. Background Art

[0002] In 2012, the U.S. Environmental Protection Agency (EPA) issued a decree requiring the average fuel efficiency of American vehicles to reach 54.5 miles per gallon by 2025. To meet this stringent standard, the automotive industry has turned to materials that can reduce vehicle weight. Commonly used lightweight materials include aluminum, composite materials such as SMC, and thermoplastics like polyolefins. SMC is also known as sheet molding compound. Generally, SMC is a high-strength composite material that mainly includes thermosetting resins, fillers, and fiber reinforcements. Thermosetting resins are usually based on unsaturated polyesters, vinyl esters, phenolic resins, or modified vinyl polyurethanes.

[0003] Polyurethane adhesives are becoming increasingly important in the automotive industry. These adhesives are commonly used to bond a variety of substrates, including coated metals, thermoplastics, and composites. They are often used in combinations, such as bonding coated metals to SMCs, SMCs to thermoplastics, and thermoplastics to coated metals.

[0004] When bonding polyurethane to SMC, many adhesives require the use of a primer or surface pretreatment, such as polishing with a scouring pad or emery cloth, to achieve optimal adhesion, especially if the adhesive cures at room temperature. Polyolefins can be challenging to bond due to their low surface energy. Typically, the surface must be treated with methods such as flame or plasma before applying the primer.

[0005] Generally speaking, industrial adhesives used to bond dissimilar materials must possess both an appropriate modulus and high elongation in addition to excellent adhesion. To meet these requirements, large amounts of plasticizers and toughening agents are added to polymerizable adhesive compositions. Furthermore, primers are used on certain materials to achieve good adhesion.

[0006] Bonding dissimilar materials presents significant challenges for industrial adhesives. Different substrate materials have different coefficients of thermal expansion. When heated, the materials expand at different rates. For example, a long aluminum extrusion bonded to glass will expand and contract, and the glass can shatter from thermal shock.

[0007] Therefore, there is a need for a polymerizable adhesive composition that provides adequate modulus, high elongation, and excellent adhesion to a variety of substrates, including coated metals, sheet molding composites (SMC), carbon fibers, and thermoplastics, without the addition of plasticizers and tougheners. Furthermore, when bonding these materials using the polymerizable adhesive composition, excellent adhesion can be achieved without the use of a primer.

[0008] It has now been found that these objects can be achieved by the compositions described below. Summary of the Invention

[0009] These and other embodiments will become apparent from the following disclosure.

[0010] The present invention relates to a two-component ("2K") adhesive composition. The composition comprises an NCO prepolymer comprising the reaction product of an isocyanate compound and a polyol, preferably having an NCO content of up to about 30%, more preferably from about 1% to 20%, even more preferably from less than about 20% to at least about 10%, or from about 1% to 10%. The composition comprises a second component comprising a second polyol having a number average molecular weight of preferably at least about 2,000 Daltons, more preferably at least about 4,000 Daltons, even more preferably at least about 8,000 Daltons, and most preferably at least about 10,000 Daltons. A third component comprises a silane adhesion promoter selected from the group consisting of isocyanurate-based silane adhesion promoters, isocyanato-based silane adhesion promoters, and combinations thereof, the silane adhesion promoter being present at a concentration of about 0.1 to 10% by weight. Optional components may include one or more catalysts, preferably a tin catalyst.

[0011] The tensile strength of the adhesive may include preferably at least about 1 MPa, further preferably at least about 5 MPa, more preferably at least about 7 MPa, even more preferably at least about 10 MPa, and an NCO to OH index of at least about 80 to 130, preferably at least about 100, more preferably at least about 110, and further preferably no more than about 125.

[0012] For specific embodiments, for low modulus embodiments, the Young's modulus of the adhesive may be at least about 1 MPa to no more than about 10 MPa, preferably no more than about 5 MPa. In the case of high modulus adhesives, the Young's modulus of the adhesive may be at least about 10 MPa, preferably at least about 25 MPa, more preferably at least about 50 MPa, and further preferably at least about 100 MPa.

[0013] With respect to lap shear bonds, particular embodiments may have a lap shear bond of at least about 2 MPa, more preferably at least about 3 MPa, even more preferably at least about 5 MPa, and even more preferably up to 10 MPa.

[0014] The present disclosure also includes a laminate and a method of making the laminate. The laminate may include a first substrate and a second substrate, and the adhesive described above sandwiched between the first and second substrates. The coefficient of thermal expansion of the first substrate differs from the coefficient of thermal expansion of the second substrate by at least about 5%, preferably at least about 10%, and more preferably at least about 15%, measured over a temperature range of about -30°C to about 82°C.

[0015] The method for preparing a laminate comprises applying the adhesive composition described above to at least one of a first substrate and a second substrate and bonding the first substrate to the second substrate. The above-mentioned factors regarding the coefficient of thermal expansion of the first substrate and the second substrate also apply to the method for making a laminate.

[0016] Further embodiments disclosed herein include alternative two-component ("2K") adhesive compositions. The alternative adhesive composition includes an NCO prepolymer comprising the reaction product of an isocyanate compound and a first polyol. The alternative two-component composition also includes a curing agent second component. The curing agent second component includes a second polyol and a monoether, wherein the second polyol preferably has a number average molecular weight of at least 15,000 Daltons.

[0017] Preferably, the alternative two-component adhesive comprises a polyurethane and has a tensile strength of preferably at least about 1 MPa, further preferably up to at least about 5 MPa, more preferably at least about 7 MPa, even more preferably at least about 10 MPa, and an NCO index of preferably at least about 80 and not more than about 150, preferably at least about 85 to about 130, more preferably not more than about 125.

[0018] With respect to specific embodiments of alternative adhesive compositions, for low modulus embodiments, the adhesive may have a Young's modulus of at least about 1 MPa to no more than about 10 MPa, preferably no more than about 5 MPa. In the case of high modulus adhesives, the adhesive may have a Young's modulus of at least about 10 MPa, preferably at least about 25 MPa, more preferably at least about 50 MPa, further preferably at least about 75 MPa, and even more preferably at least about 100 MPa.

[0019] Alternative two-component adhesives can also be used to make laminated articles. The laminated articles may include a first substrate and a second substrate, and the alternative two-component adhesive described above sandwiched between the first and second substrates. Furthermore, the coefficient of thermal expansion of the first substrate differs from the coefficient of thermal expansion of the second substrate by at least about 5%, preferably at least about 10%, and more preferably at least about 15%, measured over a temperature range of about -30°C to about 82°C.

[0020] A method for making a laminate comprising an alternative two-part adhesive comprises applying the alternative two-part adhesive to either a first substrate or a second substrate and bonding the first substrate to the second substrate. The previously discussed requirement that the coefficient of thermal expansion of the first substrate differ from the coefficient of thermal expansion of the second substrate by at least about 5% also applies to this method.

[0021] The present invention addresses the above needs. In particular, the compositions according to the present invention surprisingly achieve excellent adhesion while having high elongation and an appropriate Young's modulus. Embodiments may have a lower or higher Young's modulus, depending on the needs of a particular application. DETAILED DESCRIPTION

[0022] Before explaining in detail at least one embodiment of the present inventive concept through exemplary drawings, experiments, results and experimental procedures, it should be understood that the application of the present inventive concept is not limited to the construction and arrangement details of the components listed in the following description or exemplified in the drawings, experiments and / or results. The present inventive concept can have other embodiments or be practiced or implemented in various ways. Therefore, the language used herein is intended to give the broadest possible scope and meaning; the embodiments are merely exemplary - not exhaustive. Furthermore, it should be understood that the phraseology and terminology used herein are for descriptive purposes only and should not be considered as limiting.

[0023] Unless otherwise defined herein, the scientific and technical terms used in connection with this disclosure shall have the meanings commonly understood by those of ordinary skill in the art. In addition, unless the context otherwise requires, singular terms shall include plural forms and plural terms shall include singular forms. Generally, the terms used in connection with the chemical techniques described herein and the chemical techniques described herein are those well known and commonly used in the art. Reaction and purification techniques are carried out according to the manufacturer's specifications or as commonly used in the art or as described herein.

[0024] All patents, published patent applications, and non-patent publications mentioned in this specification are indicative of the levels of skill of those skilled in the art to which this disclosure pertains. All patents, published patent applications, and non-patent publications cited in any part of this application are hereby expressly incorporated by reference in their entirety to the same extent as if each individual patent or publication were specifically and individually indicated to be incorporated by reference.

[0025] In light of the present disclosure, all compositions and / or methods disclosed and claimed herein can be made and implemented without undue experimentation. Although the compositions and methods of the present invention have been described in terms of preferred embodiments, it will be apparent to those skilled in the art that variations in the compositions and / or methods and the steps or sequence of steps of the methods described herein can be made without departing from the concept, spirit, and scope of the present invention. All such similar substitutions and modifications apparent to those skilled in the art are considered to be within the spirit, scope, and concept of the inventive concept as defined by the appended claims.

[0026] As used in this disclosure, unless otherwise indicated, the following terms shall be understood to have the following meanings:

[0027] When used in conjunction with the term "comprising" in the claims and / or the specification, the words "a" or "an" can mean "one", but are also consistent with the meaning of "one or more", "at least one", and "one or more than one". The term "or" used in the claims means "and / or" unless it is explicitly stated to refer to only alternatives or the alternatives are mutually exclusive, although this disclosure supports definitions referring only to alternatives and "and / or". In this application, the term "about" is used to indicate that a value includes the error variation inherent in the equipment, method used to determine the value, and / or the variation between the subjects of study. The use of the term "at least one" should be understood to include one and any number greater than one, including but not limited to 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 100, etc. The term "at least one" can extend to 100 or 1000 or more, depending on the term it is connected to; furthermore, the number of 100 / 1000 should not be considered limiting, as higher limits may also produce satisfactory results. In addition, the use of the term "at least one of X, Y, and Z" should be understood to include only X, only Y, only Z, and any combination of X, Y, and Z.

[0028] As used in this specification and claims, the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”), and “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0029] As used herein, the term "or combinations thereof" refers to all permutations and combinations of the items preceding the term. For example, "A, B, C, or combinations thereof" means including at least one of the following: A, B, C, AB, AC, BC, or ABC, and also including BA, CA, CB, CBA, BCA, ACB, BAC, or CAB if the order is important in the particular context. Continuing with the example, specifically included are combinations containing one or more items or terms repeated, such as BB, AAA, MB, BBC, AAABCCCC, CBBAAA, CABABB, etc. Those skilled in the art will understand that there is no limit to the number of items or terms in any combination, unless the context clearly indicates otherwise.

[0030] The term "monomer" refers to a small molecule that chemically bonds with one or more monomers of the same or different type during polymerization to form a polymer.

[0031] The term "polymer" refers to a macromolecule comprising one or more monomer residues (repeating units) linked by covalent chemical bonds. According to this definition, polymers include compounds having from a small number of monomer units (which are generally referred to as oligomers) to a large number.

[0032] Unless otherwise stated, all standards mentioned in this application are those in effect on the filing date of this application. The following lists some examples of methods that can be used to determine characteristics. However, unless otherwise stated in the claims, these methods are equally applicable, and the claims are not limited to the following methods.

[0033] (1) Methods that can be used to determine number average molecular weight include, but are not limited to, gel permeation chromatography (GPC), vapor phase osmometry, membrane osmometry, and vapor pressure reduction.

[0034] (2) NCO%: One technique for determining NCO% is ASTM D5155.

[0035] Not necessarily limited to the above techniques. Unless otherwise stated, NCO % refers to the weight percent of free NCO in the prepolymer.

[0036] (3) NCO index is the equivalent ratio of isocyanate to hydroxyl-containing polyol.

[0037] (4) Viscosity: Viscosity was measured using a TA Instruments Discovery HR-1 rheometer with a cone and plate. For the viscosity measurements in Examples 1 and 2, the cone and plate had a diameter of 40 mm. Unless otherwise stated, the temperature was 23°C and the shear rate was 0.79 1 / s.

[0038] (5) Tensile strength of adhesive: The tensile strength can be determined according to ASTM D-638. The embodiments disclosed herein are not limited to the determination of tensile strength according to the above ASTM standard.

[0039] (6) CTE: One test method that can be used to determine the coefficient of thermal expansion ("CTE") is ASTM test method E 831. The embodiments disclosed herein are not limited to determining CTE by the above ASTM standard.

[0040] (7) The flame retardancy reported in this paper can be measured according to UL-94.

[0041] (8) Hydroxyl Value: The OH value can be determined according to ASTM D4274, a standard test method for testing polyurethane raw materials: Determination of the Hydroxyl Value of Polyols. The method for determining the OH value is not limited to the above ASTM standard. Various titration methods can also be used.

[0042] (9) Young's Modulus: Although any suitable method or apparatus may be used to determine the Young's modulus discussed herein, one exemplary apparatus that may be used to measure the modulus is the LMEC-1 Young's Modulus Meter.

[0043] "About X" means that the value of X fluctuates by 10%. In addition, in the context of the present invention, numerical ranges are understood to include the endpoint values. For example, the range of "between 0% and 25%" specifically includes the values ​​0% and 25%.

[0044] A first embodiment disclosed herein comprises a two-component ("2K") adhesive composition. Preferably, the adhesive is a polyurethane adhesive. The adhesive may comprise an NCO prepolymer. The NCO prepolymer may comprise the reaction product of an isocyanate compound and a polyol, preferably a polyisocyanate compound. Isocyanates comprising two or more isocyanate groups may be used in the present invention as stoichiometric isocyanates, excess isocyanates, and free isocyanates. These isocyanates may be monomeric or polymeric, including aromatic, aliphatic, and alicyclic polyisocyanates.

[0045] The polyisocyanate may be a diisocyanate, including aliphatic, alicyclic, aromatic, and aliphatic-aromatic diisocyanates. Specific examples of aliphatic and alicyclic diisocyanates include, but are not limited to, ethylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, trimethylene diisocyanate, cyclopentene-1,3-diisocyanate, cyclohexene-1,4-diisocyanate, cyclohexene-1,2-diisocyanate, dichlorohexamethylene diisocyanate, furfurylidene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 1-isocyanato-2-methylcycloisocyanate, Pentane, 1-isocyanate-3-isocyanate-methyl-3,5,5-trimethylcyclohexane (isophorone diisocyanate or IPDI), bis(4-isocyanatecyclohexyl)-methane, 2,4′-dicyclohexylmethane diisocyanate, 1,3- or 1,4-bis(isocyanatemethyl)-cyclohexane, bis(4-isocyanate-3-methylcyclohexyl)-methane, α′,α′,α′,α′-tetramethyl-1,3- and / or -1,4-dimethylbenzene diisocyanate, 1-isocyanate-1-methyl-4(3)-isocyanatemethylcyclohexane, 2,4- or 2,6-hexahydrotoluene diisocyanate, etc.

[0046] Examples of specific aromatic and aliphatic-aromatic diisocyanates may include, but are not limited to, 2,4- or 2,6-toluene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,2-diphenylpropane-4,4′-diisocyanate, xylene diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, diphenyl-4,4′-diisocyanate, azobenzene-4,4′-diisocyanate, diphenylsulfone-4,4′-diisocyanate, and the like. 4′-diisocyanate, 2,4-toluene diisocyanate, 1-chlorobenzene-2,4-diisocyanate, 4,4′,4″-triisocyanatotriphenylmethane, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4′-dimethyldiphenylmethane-2,2′,5,5-tetraisocyanate, and modified aromatic diisocyanates containing carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret groups.

[0047] The modified aromatic diisocyanate may be a ureaimine modified isocyanate, which may be derived from 2,4- or 2,6-toluene diisocyanate; or from 4,4′- or 2,4′-diphenylmethane diisocyanate, such as ureaimine modified 4,4′-diphenylmethane diisocyanate. Suitable ureaimine modified isocyanates include those from Huntsman Corporation. 1680 and Isonate from Dow Chemicals Company TM 143L modified MDI.

[0048] In a non-limiting embodiment, the isocyanate can be hexamethylene diisocyanate, toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), methylene bisphenyl diisocyanate (MDI), hydrogenated MDI (HMDI), or poly MDI (having a functionality greater than 2).

[0049] Stoichiometric polyols can be any polyol suitable for making polyurethanes. They can be based on polyols of polyalkylene oxide, polyester or combinations thereof, which can contain bulky side chains and / or long hydrophobic chains. Polyols based on polyalkylene oxide are commonly referred to as polyether polyols. Polyols can also include polyamide polyols, polycaprolactone polyols such as poly-ε-caprolactone polyols, polycarbonate polyols, hydroxyl-terminated polybutadienes such as fully hydrogenated hydroxyl-terminated polybutadienes and / or partially hydrogenated hydroxyl-terminated polybutadienes, polyisobutylene glycols and mixtures thereof.

[0050] The polyether polyol may include linear and / or branched polyethers having hydroxyl groups. Examples of polyether polyols include substituted and / or unsubstituted polyoxyalkylene polyols, such as polyethylene glycol, polypropylene glycol, polybutylene glycol, and the like. In addition, homopolymers and copolymers of polyoxyalkylene polyols may also be used. In particular, copolymers of polyoxyalkylene polyols may include adducts having at least one compound selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, 2-ethylhexanediol-1,3-glycerol, 1,2,6-hexanetriol, trimethylolpropane, trimethylolethane, trihydroxyphenylpropane, triethanolamine, triisopropanolamine, ethylenediamine, and ethanolamine; and at least one compound selected from the group consisting of ethylene oxide, propylene oxide, and butylene oxide.

[0051] In one embodiment, the polyether polyol may include a polymer of propylene oxide and / or a copolymer of ethylene oxide and propylene oxide. In one non-limiting embodiment, the polyether polyol is an ethylene oxide-terminated polypropylene oxide.

[0052] The number average molecular weight of the polyether polyols can generally vary from about 2,000 Daltons to about 20,000 Daltons, or from about 3,500 Daltons to about 12,000 Daltons, or from about 2,000 Daltons to about 12,000 Daltons. For example, 4220N polyol (available from Covestro) is based on propylene oxide, end-capped with ethylene oxide, and has a number average molecular weight of 4,000 Daltons.

[0053] The polyether polyols used in the present disclosure may include one or more 2-functionality polyether polyols, one or more 3-functionality polyether polyols, one or more 4-functionality polyether polyols, or combinations thereof. The number average molecular weight of the 2-functionality polyether polyol may vary between about 2,000 and about 20,000 Daltons, or within the range of about 2,000-12,000 Daltons. For example, P2010 is a polyether polyol having a number average molecular weight of 2,000 Daltons available from BASF. Another example of a suitable polyol is PPG 2000 available from PPG. The molecular weight of the trifunctional polyether polyols can vary from about 84 to about 20,000 Daltons, or from about 100 to 12,000 Daltons, including those available from BASF. TP-440 polyol. The molecular weight of the 4-functionality polyether polyol can vary between about 100 and about 20,000 Daltons, or within the range of about 400 to 12,000 Daltons. For example, 355 is a polyether polyol with a number average molecular weight of 600 Daltons, available from BASF. In certain embodiments, the molecular weight of the polyether polyol will be at least 4,000 Daltons. In alternative embodiments, the molecular weight of the polyether polyol will not exceed about 4,000 Daltons, preferably less than about 3,000 Daltons.

[0054] Polyester-based polyols, also known as polyester polyols, can include amorphous and liquid polyester polyols, fatty acid polyester polyols such as castor oil, and vegetable oils of varying molecular weights and functionalities.

[0055] Polyester polyol can be formed as the reaction product of one or more carboxylic acids and one or more polyvalent alcohols such as diol and / or triol.The carboxylic acid that can be used to form polyester polyol can include but not limited to adipic acid, glutaric acid, succinic acid, malonic acid, oxalic acid and composition thereof.The diol that can be used to form polyester polyol can include but not limited to ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, pentanediol and hexylene glycol and composition thereof.The triol that is considered to can be used to form polyester polyol can include trimethylolpropane.

[0056] Examples of fatty acid polyester polyols include castor oil, hydroxylation products of unsaturated or polyunsaturated natural oils, hydrogenation products of unsaturated or polyunsaturated polyhydroxy natural oils, polyhydroxy esters of alkylhydroxy fatty acids, polymerized natural oils, soybean polyols, alkylhydroxylated amides of fatty acids, and cashew nut shell liquid.

[0057] In a non-limiting embodiment, a polyester polyol can be obtained from the reaction of a triol with azelaic acid. The triol can be glycerol. An example of such a polyester polyol is 14001, which is derived from natural oils, is available from Emery Oleochemicals Company.

[0058] The number average molecular weight of the polyester polyols generally ranges from about 1,000 to about 20,000 Daltons, or from about 1,300 to 10,000 Daltons. TM 525 polyol (available from Eastman Chemical Company) is a 1,400 molecular weight polyester polyol that can be used.

[0059] Preferably, the NCO% in the prepolymer is up to about 30%, more preferably from about 1% to 20%, even more preferably less than about 20%, and further preferably at least about 10% to about 20%. In specific embodiments, a preferred NCO% range is from about 12% to 22%; another preferred embodiment is from about 10% to less than 19%; and in another embodiment, the preferred range is from about 14% to 19%.

[0060] The second component of the adhesive composition may include a second polyol. Preferably, the second polyol has a number average molecular weight of at least about 2,000 Daltons, more preferably at least about 4,000 Daltons, even more preferably at least about 8,000 Daltons, and most preferably greater than about 10,000 Daltons.

[0061] In one particular embodiment, the number average molecular weight of the second polyol of the second component does not exceed about 18,000 Daltons. In particular embodiments, the number average molecular weight of the second polyol may be up to about 15,000 Daltons, about 13,000 Daltons, or about 12,000 Daltons.

[0062] In another embodiment, the second polyol of the second component has a number average molecular weight of at least about 15,000 Daltons, preferably at least about 20,000 Daltons, even more preferably at least about 50,000 Daltons, and most preferably greater than about 80,000 Daltons.

[0063] Examples of suitable polyol second components may include polymer-modified polyols, preferably modified polyether polyols. In a preferred embodiment, the concentration of the polymer-modified polyol is up to about 70 wt % of the second component.

[0064] In a specific embodiment, the second polyol includes at least one polymer or prepolymer, the at least one polymer or prepolymer containing one or more polyether polyols, in which one or more organic polymer particles are dispersed or one or more organic polymer particles are grafted onto the skeleton. The one or more organic polymer particles can be based on monovinylidene aromatic monomers and copolymers of monovinylidene aromatic monomers with conjugated dienes, acrylates, methacrylates, unsaturated nitrites (nitrites) or mixtures thereof. The copolymer can be a block copolymer or a random copolymer. In a non-limiting embodiment of the present disclosure, the one or more organic polymer particles include copolymers of unsaturated nitrile, conjugated dienes and monovinylidene aromatic monomers, copolymers of unsaturated nitrile (nitrile) and monovinylidene aromatic monomers or polyureas. In another non-limiting embodiment of the present disclosure, the particles include polystyrene-acrylonitrile copolymers, which are most preferred. Preferably, the organic polymer particles are included in the prepolymer by including a polyol containing them, preferably a triol, in which organic polymer particles are dispersed, such as one or more of a thermoplastic polymer, a rubber-modified thermoplastic polymer or a polyurea dispersed in one or more triols. Preferably, the polyol in which organic polymer particles are dispersed or grafted is disclosed in U.S. Patent No. 6,709,539 to Zhou (column 4, line 13 to column 6, line 18), which is incorporated herein by reference. Preferably, the polyol used to disperse the organic particles is one or more polyether triols described herein. Preferably, a prepolymer containing one or more organic-based polymer particles is present in the composition of the present invention in an amount sufficient to increase the elasticity and modulus of the composition. In this embodiment, it is also preferred that the number average molecular weight of the second polyol is at least about 15,000 Daltons, more preferably at least about 20,000 Daltons, even more preferably at least about 50,000 Daltons, and most preferably greater than about 80,000 Daltons.

[0065] The second component may also include one or more additional polyols. The additional polyols may be the same or different from those described above for the NCO prepolymer. The additional polyols may be polyether polyols. In one non-limiting embodiment, the polyether polyol is a polymer of propylene oxide or a copolymer of ethylene oxide and propylene oxide. In another non-limiting embodiment, the free polyol may be a polyester polyol based on cardanol or a poly-ε-caprolactone polyol.

[0066] The adhesive composition may further include a silane adhesion promoter selected from the group consisting of an isocyanurate-based silane adhesion promoter, an isocyanate-based silane adhesion promoter, and combinations thereof. The concentration of the silane adhesion promoter may be from about 0.1 to 10 wt %. A non-limiting example of an isocyanurate-based silane includes, but is not limited to, 1,3,5-tris[3-(trimethoxysilyl)propyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione. Other examples include (isocyanate methyl) methyl dimethoxysilane, 3-isocyanate propyl trimethoxysilane, 3-isocyanate propyl triethoxysilane, 3-isocyanate propyl methyl dimethoxysilane, 3-isocyanate propyl methyl diethoxysilane, tris [3- (trimethoxysilyl) propyl] isocyanurate, tris [3- (triethoxysilyl) propyl] isocyanurate, isocyanate methyl trimethoxysilane, isocyanate methyl triethoxysilane. The above isocyanurate-based compounds can be used in any combination thereof.

[0067] Optional ingredients of the adhesive may include one or more catalysts, preferably tin catalysts. In another optional aspect, the adhesive composition may contain less than about 1 wt% solvent and / or water, preferably not more than the nominal amount of either solvent and water.

[0068] The adhesive composition may further include a fourth component selected from the group consisting of at least one of epoxy-functional silane adhesion promoters, polyether diamines, monoethers, and combinations thereof. The concentration of the fourth component may be no more than about 20 wt%, preferably at least about 0.5 wt%.

[0069] Non-limiting examples of suitable epoxy-functional silane adhesion promoters include 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-(2,3-glycidoxypropyl)methyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and combinations thereof.

[0070] Non-limiting examples of polyetheramines include diamines or triamines based on polyoxyalkylenepolyamines, such as Jeffamines or Baxxodur polyetheramines.

[0071] Non-limiting examples of monoethers include poly(ethylene glycol-ran-propylene glycol) monobutyl ether, poly(propylene glycol) monobutyl ether, poly(ethylene-co-1,2-butene) monool, polyester ether monool, C12 to C18 alcohols, and combinations thereof.

[0072] The adhesive composition may further include a flame-retardant package. The flame-retardant package may be present in the adhesive composition in an amount up to about 25 wt %. In a particular embodiment, the flame-retardant package may be included in the curing agent of the 2K polyurethane adhesive composition.

[0073] In general, the flame retardant package can include any combination of the following: non-halogenated phosphate esters, non-halogenated phosphate polyesters, halogen-containing phosphate esters, halogen-containing phosphate polyesters, and halogen-free phosphate polyesters. More specific examples of flame retardants include: (1) halogenated flame retardants, also known as organohalogen flame retardants, which contain chlorine or bromine bonded to carbon, and (2) organophosphorus flame retardants, which contain phosphorus bonded to carbon.

[0074] Examples of compounds that can be used in halogen-free systems include aluminum oxide trihydrate, magnesium hydroxide, antimony trioxide red phosphorus, ammonium polyphosphate, zinc borate, and any combination thereof. Examples of halogen-containing flame retardants include tris(2-chloropropyl) phosphate (TCPP), (2-hydroxyethoxy)ethyl 2-hydroxypropyl 3,4,5,6-tetrabromophthalate (Saytex RB-79), and combinations thereof.

[0075] A specific example of a brominated flame retardant package can include Saytex RB-79 in combination with a chlorinated phosphate flame retardant. Another specific example of a flame retardant can be antimony trioxide (such as FireGard ATO) combined with a halogen source such as decabromodiphenylethane (available as "Broshield 21-B"). Another example of a flame retardant package can include an organophosphorus material, either added to the adhesive or chemically attached to the polymer.

[0076] If desired, the above components may be used in any combination thereof, such as, but not limited to, a combination of compounds constituting a halogenated system and compounds included in a halogen-free system.

[0077] The adhesive compositions disclosed herein may include less than about 10 wt % plasticizer, preferably less than about 5 wt %, more preferably less than about 4 wt %, even more preferably less than about 2 wt %, and most preferably less than about 1 wt %. Specific embodiments may have less than about 0.5 wt %, less than about 0.1 wt %, or less than the limit of detection of plasticizer.

[0078] The adhesive composition may include a tertiary amine, including a blocked tertiary amine. Preferably, the tertiary amine includes at least one of 1,4-diazabicyclo[2.2.2]octane solution, DBU (diazabicycloundecene), 1,4-diazabicyclooctane, and combinations thereof.

[0079] Another component of the adhesive composition may include a chain extender comprising a polyol or aromatic diamine having a functionality of at least 2 hydroxyl units. Suitable chain extenders include diols and triols. In one embodiment, the chain extender can be a low molecular weight compound and can be hydroxyl terminated or amine terminated. In a non-limiting embodiment, the chain extender compound can be a hydroxyl terminated low molecular weight polyol having a molecular weight range of about 25 to about 1,000 Daltons, or about 32 to about 600 Daltons. The low molecular weight chain extender compound can be selected from the group consisting of ethylene glycol, diethylene glycol, 1,5-pentanediol, 1,3-pentanediol, 1,3-butanediol, 1,4-butanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,6-hexanediol, dipropylene glycol, neopentyl glycol, 3-methylpentanediol, 1,4-cyclohexanedimethanol, and combinations thereof.

[0080] Examples of suitable aromatic diamine compounds include diethyltoluenediamine, tetrapropoxylated ethylenediamine, methylenebis(o-ethylaniline), and combinations thereof.

[0081] The adhesive composition may also include various fillers, rheology modifiers, colorants, and additives as desired. Several examples of typical fillers for polyurethane adhesives include talc, precipitated calcium carbonate, and combinations thereof.

[0082] With respect to the 2K adhesives disclosed herein, the second polyol component may include a curing agent portion ("Part B"), the NCO prepolymer may include a Part A prepolymer portion, and the volume ratio of Part A to Part B prepolymer may include about 1:10 to about 10:1. Preferred volume ratios may include about 1:1, at least about 1:1.5, at least about 1:4, and at least about 1:2.

[0083] Preferably, the tensile strength of the adhesive comprises at least about 1 MPa, further preferably to at least about 5 MPa, more preferably at least about 7 MPa, even more preferably at least about 10 MPa, and the NCO to OH index is at least about 80 to 130, preferably at least about 100, more preferably at least about 110, and further preferably no more than about 125.

[0084] Preferably, the Young's modulus of the adhesive composition is at least about 1 MPa to more than 100 MPa. With respect to specific embodiments of the adhesive composition, for low modulus embodiments, the Young's modulus of the adhesive may be at least about 1 MPa to no more than about 10 MPa, preferably no more than about 5 MPa. In the case of high modulus adhesives, the Young's modulus may be at least about 10 MPa, preferably at least about 25 MPa, more preferably at least about 50 MPa, even more preferably at least about 75 MPa, and further preferably at least about 100 MPa.

[0085] The disclosed adhesives can be part of a laminate. Preferably, the laminate includes a first substrate and a second substrate. Preferably, any of the adhesives disclosed herein is sandwiched between the first substrate and the second substrate. The first substrate has a coefficient of thermal expansion (CTE) that differs from the coefficient of thermal expansion (CTE) of the second substrate by at least about 5%, preferably by at least about 10%, and more preferably by at least about 15%, measured in the temperature range of about -30°C to about 82°C.

[0086] Preferably, the laminate is formed without the use of a sufficient amount of primer to aid bonding of the adhesive to one or both substrates, and more preferably without the use of any primer.

[0087] The laminates disclosed herein are not limited to any particular substrate, except that the two substrates have different CTEs as described above. Non-limiting examples of substrates include metals, coated metals, thermoplastics, and composite materials. Preferably, the composite material may include carbon fiber or sheet molded composite. Preferably, the metal may include at least one of aluminum, steel, stainless steel, galvanized steel, carbon steel, and alloys thereof. Examples of thermoplastics may include at least one of polyamides, polyolefins, and combinations thereof. Preferably, the coating used to coat the metal includes nickel. Preferred polyolefins include polycarbonate, polyethylene terephthalate, polybutylene terephthalate, and combinations thereof.

[0088] The present disclosure also includes a method for making the aforementioned laminate. The method comprises applying any of the adhesives disclosed herein to either a first substrate or a second substrate. The method further comprises bonding the first substrate to the second substrate. The aforementioned disclosure regarding CTE also applies to the method for making the laminate.

[0089] Optionally, the method may not include applying a primer to either the first substrate or the second substrate, preferably, both the first substrate and the second substrate. Furthermore, the method may not include the step of mechanically pretreating either the first substrate or the second substrate prior to applying the adhesive, preferably, neither the first substrate nor the second substrate is mechanically pretreated.

[0090] The method of preparing the laminate may further include the step of curing the adhesive at a temperature below about 140° C., preferably below about 120° C., also preferably below about 105° C., more preferably below about 100° C., even more preferably below about 90° C., and further preferably below about 80° C. In particular embodiments, preferred curing temperatures may include below about 75° C., below about 65° C., below about 50° C., or not exceeding room temperature.

[0091] The adhesive compositions disclosed herein include alternative embodiments. An alternative embodiment may also be a 2K polyurethane adhesive composition. The alternative adhesive may include an NCO prepolymer comprising a reaction product of an isocyanate compound and a first polyol. The alternative adhesive composition may include a curing agent second component. The curing agent second component may include a second polyol and a monoether.

[0092] The above disclosure on the NCO prepolymer is also applicable to the NCO prepolymer in the adhesive composition. In addition, the above disclosure on the second polyol is also applicable to the second polyol that replaces the curing agent in the adhesive composition.

[0093] In one embodiment, the second polyol replacing the curing agent in the adhesive embodiment comprises a polyoxyalkylene polyol having a hydroxyl number of at least about 15 mg KOH / g, preferably at least about 17 mg KOH / g, more preferably no more than about 30 mg KOH / g, and even more preferably no more than about 25 mg KOH / g.

[0094] The second polyol replacing the curing agent in the adhesive composition may have a number average molecular weight of at least about 15,000 Daltons, preferably at least about 20,000 Daltons, more preferably at least about 50,000 Daltons, and most preferably greater than about 80,000 Daltons.

[0095] In one embodiment, the second polyol comprises at least one polymer or prepolymer, the at least one polymer or prepolymer containing one or more polyether polyols in which one or more organic polymer particles are dispersed or grafted onto the skeleton with one or more organic polymer particles dispersed therein. The one or more organic-based polymer particles can be based on monovinylidene aromatic monomers and copolymers of monovinylidene aromatic monomers with conjugated dienes, acrylates, methacrylates, unsaturated nitriles or mixtures thereof. The copolymers can be block copolymers or random copolymers. In a non-limiting embodiment of the present disclosure, the one or more organic-based polymer particles include copolymers of unsaturated nitriles, conjugated dienes and monovinylidene aromatic monomers, copolymers of unsaturated nitriles and monovinylidene aromatic monomers or polyureas. In another non-limiting embodiment of the present disclosure, the particles include polystyrene-acrylonitrile copolymers, which is most preferred. Preferably, these particles are included in the prepolymer by including a polyol containing these organic-based polymer particles, preferably a triol, the polyol having particles of an organic-based polymer dispersed therein, for example, one or more of thermoplastic polymers, rubber-modified thermoplastic polymers or polyurea particles dispersed in one or more triols. Preferred polyols in which organic polymer particles are dispersed or grafted are disclosed in Zhou, U.S. Patent No. 6,709,539, at column 4, line 13 to column 6, line 18, incorporated herein by reference. Preferably, the polyol used to disperse the organic particles is one or more polyether triols described herein.

[0096] The concentration of the alternative adhesive composition curative second polyol may comprise no more than 60 wt %, preferably no more than about 50 wt %, more preferably about 10 to 40 wt %, and even more preferably about 15 to 35 wt %, based on the weight of the curative second component.

[0097] The monoether in the curing component of the alternative adhesive composition may include a poly(propylene glycol) monoether, preferably a poly(propylene glycol) monobutyl ether. The concentration of the monoether may be no more than about 25 wt %, preferably about 0.5 to 20 wt %, more preferably about 1 to 15 wt %, and more preferably about 3 to 12 wt %, based on the weight of the curing agent second component. The above examples of monoethers are suitable for use in alternative adhesive embodiments and are incorporated herein as if fully rewritten.

[0098] The second curing agent component may further include a third polyol having a number average molecular weight of at least about 4,000 Daltons. The curing agent of the alternative adhesive composition may further include a diol or triol, preferably a diol primary alcohol. In addition, it is preferred that the alternative adhesive contain less than about 1% by weight of a plasticizer, and preferably contain no plasticizer.

[0099] Preferably, the tensile strength of the alternative binder is at least about 1 MPa, more preferably at least up to about 5 MPa, further preferably at least about 7 MPa, and even more preferably at least about 10 MPa. Preferably, the NCO index of the alternative binder is at least about 80 and no more than about 150, more preferably at least about 85 to about 130, and further preferably no more than about 125.

[0100] The volume ratio of the NCO prepolymer to the curing agent second component may include about 1:10 to about 10:1, and preferred volume ratios may include about 1:1, at least about 1.5:1, at least about 4:1, and at least about 2:1.

[0101] The Young's modulus of the alternative adhesive may be at least about 1 MPa to more than about 100 MPa. With respect to specific embodiments of the alternative adhesive composition, for low modulus embodiments, the Young's modulus of the adhesive may be at least about 1 MPa to no more than about 10 MPa, preferably no more than about 5 MPa. In the case of high modulus adhesives, the Young's modulus of the adhesive may be at least about 10 MPa, preferably at least about 25 MPa, more preferably at least about 50 MPa, even more preferably at least about 75 MPa, and further preferably at least about 100 MPa.

[0102] The above disclosures regarding laminates and methods of making laminates may also be applied to alternative adhesive compositions.

[0103] All the above-mentioned embodiments can be combined with each other. In particular, the various above-mentioned components in the composition, especially the preferred embodiments, can be combined with each other.

[0104] The compositions and applications of the present disclosure can be prepared and used according to the following examples. These examples are provided herein only for the purpose of illustrating the present disclosure and are not limiting. For example, the preparation of the compositions and applications thereof are not limited to these examples.

[0105] Example

[0106] Example 1: Materials and Methods

[0107] Material

[0108] Prepare the following materials:

[0109] 1. Sample 1A Part 1 Isocyanate Silane Adhesion Promoter in Prepolymer

[0110] Table 1-1

[0111] Material Material Description wt% PPG2000 PPG2000 polyol 16.0 Pluracol TP-440 Trifunctional low molecular weight polyol 1.9 Rubinate M Polymeric MDI 37.0 talc filler 10.5 Aerosil R202 Fumed silica 1.4 molecular sieves Reduce moisture 8.7 Rubinate 9310 Carbodiimide modified 4,4'-MDI, 22.0 Silane A-187 Epoxy-functional silanes 1.5 VPS 7163 Isocyanate silane 1.0 total 100.0

[0112] The procedure for making Part A is as follows:

[0113] 1. Add polyol to the reactor and heat to 90°C.

[0114] 2. When the temperature reaches 80°C, add talc under low shear mixing conditions until it is completely wetted.

[0115] 3. Add the fumed silica under low shear mixing until completely wetted.

[0116] 4. Mix under vacuum for 60 minutes and heat until the temperature reaches 93°C.

[0117] 5. Take samples and test the moisture content until the moisture content reaches <400ppm.

[0118] 6. Cool the temperature to 83°C.

[0119] 7. Add Rubinate M and molecular sieves.

[0120] 8. Apply vacuum again and mix for 2 hours.

[0121] 9. Add Rubinate 9310 and apply vacuum again for 1 hour.

[0122] 10. Cool the batch to 70°C.

[0123] 11. Add silane and mix for 10 minutes.

[0124] 12. Degas for 30 minutes.

[0125] 13. Samples were taken to test viscosity and isocyanate percentage (NCO%). NCO% = 16.5%, 30256 cP at 0.79 1 / s.

[0126] Sample 2 intermediate

[0127] Table 1-2

[0128]

[0129] program:

[0130] 1. Add TP-440 and Acclaim 4220N to the reactor and heat to 93°C.

[0131] 2. Apply vacuum for 60 minutes and check the moisture content until the moisture content reaches <300 ppm.

[0132] 3. Add Mondur MLQ and Rubinate 9310 into the reactor and keep it under vacuum for 2 hours.

[0133] 4. Cool the batch.

[0134] Sample 3

[0135] Table 1-3 Partial curing agent for sample 3B

[0136]

[0137] The procedure for forming Part B, totaling 100.0, is as follows:

[0138] 1. Add polyol to the reactor, heat to 93°C and maintain this temperature.

[0139] 2. At 93°C, add talc and fumed silica and mix at low shear until completely wetted.

[0140] 3. Mix under vacuum and high shear for 60 minutes.

[0141] 4. Check the moisture content until it reaches <300ppm.

[0142] 5. Reduce the temperature to 65°C-70°C.

[0143] 6. Add 1,4-butanediol.

[0144] 7. Add piperazine and Jeffamine D-400 and mix at 65-70°C for 30 minutes.

[0145] 8. Add sieve, catalyst and colorant and mix at 65-70°C for 60 minutes.

[0146] 9. Degas at 65-70°C for 30 minutes.

[0147] 10. At a shear rate of 0.79 1 / s, the sample viscosity is 32023 cP.

[0148] The test results for Sample 1 and Sample 3 are summarized in Tables 1-3 and 1-4 below.

[0149] Table 1-4 General properties of sample 1 prepolymer / sample 3 curing agent

[0150]

[0151] Table 1-5 Mechanical properties of sample 1 prepolymer / sample 3 curing agent

[0152]

[0153] Sample 4B partially contains a flame retardant curing agent

[0154] Table 1-6

[0155] Procedure for preparing sample 4:

[0156] 1. Add polyol and intermediate into the reactor, heat to 93°C and maintain the temperature.

[0157] 2. At 93°C, add talc, fumed silica, and ammonium polyphosphate and mix at low shear until completely wetted.

[0158] 3. Apply vacuum for 60 minutes and monitor moisture content until it reaches a level of <300 ppm.

[0159] 4. Reduce the temperature to 65°C-70°C.

[0160] 5. Join BDO.

[0161] 6. Add 1,8-diaminonaphthalene, Jeffamine D-400 and Exolite OP560 and mix at 65-70°C for 30 minutes.

[0162] 7. Add sieve and catalyst and mix at 65-70°C for 60 minutes.

[0163] 8. Degas at 65-70°C for 30 minutes.

[0164] 9. Take samples to test viscosity and adjust as needed.

[0165] 10. Filter the batch.

[0166] Table 1-7

[0167]

[0168] Examples of adhesives made from Sample 1 and Sample 4 were tested for flame retardancy.

[0169] Adhesives made from Samples 1 and 4 passed the UL-94 V0 test at a 0.25 mm bond gap and the UL-94 V1 test at a 0.75 mm bond gap. Control Sample 1 failed any flame retardancy tests. The results are summarized in Tables 1-8.

[0170] Table 1-8. UL-94 test results

[0171] UL-94-Test ID thickness t1(s) t2(s) Adhesive of sample 1 / 4 (V0) 0.25mm 0 0 Adhesive of sample 1 / 4 (V1) 0.75mm 10 48 Control 1 (V0) 0.25mm 40 combustion Control 1 (V1) 0.75mm combustion combustion

[0172] Mark t1 indicates the time when the sample starts to burn, and t2 indicates the time when the sample stops burning. In the case of V0, the sample did not burn. In the case of V1, the sample started to burn at 10 seconds and the combustion was extinguished at 48 seconds.

[0173] In contrast, Control 1 failed the V0 test because it continued to burn for more than 10 seconds after starting to burn. Similarly, Control 1 continued to burn for more than 60 seconds and therefore failed the test.

[0174] Example 2

[0175] Sample 5A Partial Prepolymer

[0176] Table 2-1

[0177] Material Material Description wt% PPG 2000 PPG 2000 polyol 16.0 Pluracol TP-440 Trifunctional low molecular weight polyol 1.9 Rubinate 9720 Carbodiimide modified 4,4'-MDI, 62.0 RCS Talc filler 8.5 5A molecular sieve Moisture scavengers 7.0 Aerosil R202 Fumed silica 2.1 Silane A-187 Epoxy-functional silanes 1.5 VPS 7163 Isocyanurate silane 1.0 total 100.0

[0178] program

[0179] 1. Add polyol to the reactor and heat to 90°C.

[0180] 2. When the temperature reaches 80°C, add talc and mix with low shear until all wetted.

[0181] 3. Add polyol to the reactor and heat to 90°C.

[0182] 4. Add polyol to the reactor and heat to 90°C.

[0183] 5. When the temperature reaches 80°C, add talc and mix with low shear until all wetted.

[0184] 6. Mix at high shear under vacuum for 60 minutes and heat until the temperature reaches 93°C.

[0185] 7. Take samples to test the moisture content until the moisture content reaches <400PPM.

[0186] 8. Cool to 83°C.

[0187] 9. Add about 2 / 3 of Rubinate 9720 and molecular sieves.

[0188] 10. Slowly add the silica at a low shear rate and continue mixing until wetted.

[0189] 11. Apply vacuum again and mix at 83°C for 2 hours.

[0190] 12. Add the remaining Rubinate 9720.

[0191] 13. Apply vacuum again for 60 minutes.

[0192] 14. Cool the reactor to 70°C.

[0193] 15. Add Silane-187 and VPS 7163.

[0194] 16. Degas for 30 minutes.

[0195] 17. Take samples to test viscosity and NCO%.

[0196] a. Target NCO% is 17%.

[0197] 18. Filter the batch.

[0198] result:

[0199]

[0200] Sample 6 intermediate

[0201] Table 2-2

[0202]

[0203] program:

[0204] 1. Add Pluracol TP-440 and Acclaim 4220N and heat to 83°C.

[0205] 2. Apply vacuum for 60 minutes and monitor moisture content until it reaches <300 ppm.

[0206] 3. Add Mondur MLQ and Rubinate 9310 and maintain the temperature at 83°C under vacuum for 2 hours.

[0207] 4. Cool the batch.

[0208] Sample 7 contains glass beads and PEP 550 curing agent

[0209] Table 2-3

[0210]

[0211] program:

[0212] 1. Add polyol and intermediate of Sample 6. Apply vacuum and heat to 94°C.

[0213] 2. At 94°C, add talc, fumed silica and ammonium polyphosphate at a low shear rate.

[0214] 3. Mix at high shear rate under vacuum for 60 minutes and monitor moisture content until the measured

[0215] <300ppm.

[0216] 4. Reduce the temperature to 65-70°C.

[0217] 5. Join BDO.

[0218] 6. Add 1,8-diaminonaphthalene, PEP 550, Jeffamine D-400, and liquid phosphate ester and mix at 65-70°C for 30 minutes.

[0219] 7. Add sieve and catalyst and mix at 65-70°C for 60 minutes.

[0220] 8. Degas at 65-70°C for 30 minutes.

[0221] 9. Take samples and measure viscosity.

[0222] a. At a shear rate of 0.79 1 / s, the viscosity is 27230 cP.

[0223] 10. Filter the batch.

[0224] Sample 8 does not contain Jeffamine D-400 curing agent

[0225] Table 2-4 Partial curing agent for sample 8B

[0226]

[0227] program:

[0228] 1. Add polyol and intermediate of Sample 6.

[0229] 2. Apply vacuum and heat to 94°C.

[0230] 3. At 94°C, add talc, fumed silica and ammonium polyphosphate at a low shear rate.

[0231] 4. Mix at high shear rate under vacuum for 60 minutes and monitor moisture content until the measured

[0232] <300ppm moisture content.

[0233] 5. Reduce the temperature to 65-70°C.

[0234] 6. Join BDO.

[0235] 7. Add 1,8-diaminonaphthalene, PEP 550, and liquid phosphate ester and mix at 65-70°C for 30 minutes.

[0236] 8. Add sieve and catalyst and mix at 65-70°C for 60 minutes.

[0237] 9. Degas at 65-70°C for 30 minutes.

[0238] 10. Sampling and viscosity measurement

[0239] a. At a shear rate of 0.79 1 / s, the viscosity is 15000 cP.

[0240] 11. Filter the batch.

[0241] Compare the results of Sample 5 / Sample 7 (NCO index of 124, volume ratio of 1:1) and Sample 5 / Sample 8 (NCO index of 121, volume ratio of 1:1).

[0242] Example 3

[0243] Tables 3-11 and 3-12 show the formulations for Samples 11 to 14. The general procedures for preparing the prepolymer and curing agent are shown in Tables 3-13 and 3-14.

[0244] Samples 11-14 are shown in Table 3-15. The prepolymers and curing agents prepared in Tables 3-11 and 3-12 were loaded into side-by-side cartridges and pumped through a static mixer to achieve thorough mixing, as shown in Table 3-15. The mixed polymerizable adhesive composition was then applied directly from the static mixer to one side of the test substrate.

[0245] Lap shear testing was performed to measure the lap shear strength and failure mode of the adhesive bond. The lap shear test specimens were prepared by overlapping the last 2.5 cm of a pair of 10 x 2.5 cm specimens to obtain a 17.8 cm long specimen with adhesive and 0.76 mm glass spacer beads between the overlapping portions. The test specimens were placed between a double-sided fixture and maintained at the curing temperature until solidified. The test specimens were then removed from the fixture and tested at a temperature of about 20 to 25°C for about 24 to 72 hours. Lap shear testing was performed in accordance with ASTM D5868 with a crosshead speed of 2 inches per minute. The entire contents of ASTM D5868 are incorporated herein by reference. Unless otherwise stated, all adhesives were prepared in an isocyanate index range of about 95 to about 105.

[0246] Samples 11-14 were ambient cured and heat cured and evaluated. Controls 12 and 13 were commercially available 2K polyurethane adhesives. The controls did not include the epoxy functional silane, the isocyanurate silane, the polyol having a number average molecular weight of at least 15,000 Daltons, and the monoether. Control 12 showed good performance when heat cured, but did not achieve the required 90% cohesive failure mode when cured at ambient temperature, tested at 82°C and after 1 week of water immersion. In contrast, Sample 11 (containing the monoether) exhibited excellent lap shear strength and failure mode under both cure conditions.

[0247] Sample 12 is a low modulus adhesive containing Arlamol PB14 and Hyperlite E-855 in its curing agent (monoether and a second polyol with a number average molecular weight of at least 15,000 daltons). The NCO index of sample 12 is 103, and the MDI content in the organic phase is 13%. As used herein, the organic phase refers to all organic materials in the adhesive composition, excluding inorganic materials. Control 13 was used as a reference in this test, and its NCO index was 112, and the MDI content in the organic phase was 25%. Both ambient and heat cures were evaluated. Control 13 showed very good performance in the heat cure process, but had poor strength and poor failure modes when ambient cured. Sample 12 showed excellent lap shear strength and failure modes under both cure conditions.

[0248] Adhesives prepared from Samples 12-14 were used to bond glass-filled polypropylene (GFPP) to thermoplastic olefin (TPO), a low-surface-energy substrate, and PP to bare aluminum. Prior to bonding, the GFPP and TPO surfaces were IPA wiped and flame-treated, and the Al-6061 surface was polished. Lap shear testing of the cured adhesives was conducted at room temperature (RT) and after one week of water immersion. Samples 12-14 (curing agents containing Arlamol PB14 and Hyperlite E-855) exhibited low NCO indices (103 for Sample 12, 100 for Sample 13, and 104 for Sample 14) and low MDI percentages in the organic phase (13% for Sample 12, 17% for Sample 13, and 12% for Sample 14). The results in Tables 3-18 demonstrate that both adhesives produced high lap strength and excellent bonds on the tested substrates.

[0249] Table 3-11. Part A prepolymer formulation, including polyurethane prepolymers

[0250] Sample 11A Sample 12A Sample 13A Sample 14A PPG400 0 30 25 25.0 Acclaim 8200 0 25.0 23 31.0 PPG2000 13.9 0 0 0 Pluracol TP 440 2.0 0 0 0 filler 7.0 13.5 14.75 15.1 Aerosil 2.9 1.2 0.8 0.9 molecular sieves 7.3 9 9.4 9.0 Rubinate 9310 66.4 19 24.5 19.0 Silane* 0 2.5 2.5 0

[0251] (*)Silanes included: 1.5 parts epoxysilane A-187 and 1.0 parts isocyanuratesilane VPS 7163

[0252] Table 3-12. Part B curing agent formula

[0253] Sample 11B Sample 12B Sample 13B Sample 14B Acclaim 4220N 20.3 12 36.7 24.5 Hyperlite E-855 0 45.0 17 35 Arlamol PB 14 6 8.2 6 10.5 Pliogrip 8800 34.0 0 0 0 filler 18.5 25.5 27.6 25 Aerosil 3.8 0.6 0.9 1.2 1,4-Butanediol 14.4 2.7 4.5 2.6 Piperazine 1.3 0.4 0.6 0.4 Tin catalyst <0.1 0.1 0.2 <0.1 Polycat SA1 0 0 0.2 0.2 DABCO 33LV 0 0 0 <0.1 DBU 0 0.1 0 0 Jeffamine D-400 0 5 6 0 Black pigment 0.9 0.5 0.5 0.5 molecular sieves 0.9 0 0 0

[0254] Table 3-13. General procedure for preparing prepolymers

[0255] step 1 Add polyol 2 Heat to 180°F-200°F 3 Add RCS talc and Aerosil R202 and mix under low shear until all are wetted. 4 Apply vacuum and high shear until the moisture content reaches <400ppm 5 At 180°F add Rubinate 9310 and sieve 6 Add silane and degas for 30 minutes 7 Discharging

[0256] Table 3-14. General procedure for preparing curing agent

[0257]

[0258] Table 3-15. Prepolymer and curing agent combinations

[0259]

[0260] Table 3-18. Lap shear testing on dissimilar substrates

[0261]

[0262] CH: cohesive failure

[0263] Table 3-19. Adhesion performance

[0264] NCO Index MDI wt% Modulus (MPa) Control 13 112 25 6 Sample 12 103 13 3.5 Sample 13 100 17 4 Sample 14 104 17 3

[0265] Although the present invention has been described in detail by certain preferred embodiments, it should be understood that the present disclosure is not limited to these specific embodiments. On the contrary, in view of this disclosure, those skilled in the art will make many modifications and variations without departing from the scope and spirit of the present invention.

[0266] aspect

[0267] In addition to the embodiments described in the Summary, Detailed Description, and Claims, the present disclosure may further include aspects such as those listed below.

[0268] The first aspect is a two-component adhesive composition comprising:

[0269] a. NCO prepolymers comprising the reaction product of an isocyanate compound and a polyol, preferably having an NCO % in the prepolymer of up to about 30%, more preferably from about 1% to 20%, even more preferably from less than 20% to at least 10%, or from about 1% to 10%,

[0270] b. A second component comprising a second polyol, preferably having a number average molecular weight of at least about 2,000 Daltons, more preferably at least about 4,000 Daltons, even more preferably at least about 8,000 Daltons, and most preferably greater than 10,000 Daltons.

[0271] c. A silane adhesion promoter selected from the group consisting of isocyanurate-based silane adhesion promoters, isocyanate-based silane adhesion promoters, and combinations thereof, the concentration of the silane adhesion promoter being from about 0.1 to 10 wt % (non-limiting examples of isocyanurate-based silanes: 1,3,5-triazol-2-yl)propane

[0272] [3-(Trimethoxysilyl)propyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione); and

[0273] d. optional components, which may include one or more catalysts, preferably tin catalysts; and

[0274] The properties of the adhesive may include one or more of the following:

[0275] (i) Preferably, the tensile strength of the adhesive comprises at least about 1 MPa, more preferably at least about 5 MPa, even more preferably at least about 7 MPa, even more preferably at least about 10

[0276] MPa;

[0277] (ii) a Young's modulus of at least about 1 MPa;

[0278] (iii) an NCO to OH index of at least about 80 to 130, preferably at least about 100, more preferably at least about 110, and even more preferably no more than about 125;

[0279] (iv) and combinations thereof.

[0280] In a second aspect, the adhesive of aspect 1 further comprises a fourth component selected from the group consisting of at least one of an epoxy-functional silane adhesion promoter, a polyether diamine, a monoether, and a combination thereof, wherein the concentration of the fourth component is no more than about 20 wt %, preferably at least about 0.5 wt %, and preferably the fourth component comprises at least one of an epoxy-functional silane adhesion promoter, a monoether, and a combination thereof.

[0281] In a third aspect, the adhesive of any of aspects 1 or 2, wherein the second polyol of the second component comprises a polymer-modified polyol, preferably a modified polyether polyol, and the concentration of the polymer-modified polyol is up to about 70 wt % of the concentration of the second component.

[0282] In a fourth aspect, the adhesive of any of the preceding aspects, comprising a flame retardant package, wherein the flame retardant package comprises up to about 25 wt % of the adhesive composition.

[0283] In a fifth aspect, the adhesive composition of any of the preceding aspects, wherein the composition comprises less than about 10 wt %, preferably less than about 5 wt %, more preferably less than about 4 wt %, even more preferably less than about 2 wt %, and most preferably less than about 1 wt % of plasticizer.

[0284] In a sixth aspect, the adhesive composition of any of the above aspects comprises a tertiary amine, preferably the tertiary amine comprises at least one of the following: 1,4-diazabicyclo[2.2.2]octane solution, DBU (diazabicycloundecene), 1,4-diazabicyclooctane and combinations thereof.

[0285] In a seventh aspect, the adhesive composition of any of the preceding aspects comprises a chain extender comprising a polyol having a functionality of at least 2, preferably such that the NCO% of the adhesive accounts for no more than about 30%, more preferably no more than about 25%, even further preferably no more than about 20 wt%, and most preferably at least about 10 wt%.

[0286] In an eighth aspect, a laminate comprises a first substrate and a second substrate, and the adhesive of any of the preceding aspects is sandwiched between the first substrate and the second substrate, wherein the coefficient of thermal expansion of the first substrate differs from the coefficient of thermal expansion of the second substrate by at least about 5%, preferably at least about 10%, and more preferably at least about 15%, measured in the temperature range of about -30°C to about 82°C.

[0287] In a ninth aspect, the laminate of aspect 8 is free of a primer in an amount sufficient to aid in bonding the adhesive to either the first substrate or the second substrate.

[0288] In a tenth aspect, the laminate of any of aspects 8 or 9, wherein the first substrate comprises one of the following: metal, coated metal, thermoplastic, composite material, preferably the composite material comprises carbon fiber, sheet molded composite material, preferably the metal may comprise at least one of aluminum, steel, stainless steel, galvanized steel, carbon steel and alloys thereof, preferably the thermoplastic comprises at least one of polyamide, polyolefin and combinations thereof, preferably the coating of the coated metal comprises nickel, preferably the polyolefin comprises polycarbonate, polyethylene terephthalate, polybutylene terephthalate and combinations thereof.

[0289] An eleventh aspect is a method of making a laminated product, comprising:

[0290] a. applying the adhesive of any one of aspects 1-8 above to either the first substrate or the second substrate;

[0291] b. bonding the first substrate to the second substrate;

[0292] The thermal expansion coefficient of the first substrate differs from the thermal expansion coefficient of the second substrate by at least about 5%, measured in a temperature range of about -30°C to about 82°C.

[0293] A twelfth aspect includes the method of aspect 11, wherein the method does not comprise the step of applying a primer to either the first substrate or the second substrate, preferably both the first substrate and the second substrate.

[0294] In a thirteenth aspect, an aspect of either aspect 11 or 12, excluding the step of mechanically pre-treating either the first substrate or the second substrate, preferably both the first substrate and the second substrate, prior to applying the adhesive.

[0295] A fourteenth aspect applies to any of aspects 11 to 13, further comprising curing the adhesive at a temperature of less than about 140°C, preferably less than about 120°C, also preferably less than about 105°C, more preferably less than about 100°C, even more preferably less than about 90°C, and further preferably less than about 80°C.

[0296] The fifteenth aspect is applicable to the two-component adhesive of any one of aspects 1 to 8, wherein the second polyol component includes a curing agent part (part B) and a part A including an NCO prepolymer, and the volume ratio of part A to part B includes about 1:10 to about 10:1, and the preferred volume ratio may include about 1:1, at least about 1.5:1, at least about 4:1 and at least about 1:2.

[0297] Other aspects disclosed herein include a two-component ("2K") adhesive composition of a sixteenth aspect, the composition comprising:

[0298] a. an NCO prepolymer comprising a reaction product of an isocyanate compound and a first polyol;

[0299] b. The second component of the curing agent includes:

[0300] (i) a second polyol and

[0301] (ii) Monoether

[0302] The properties of the adhesive may include one or more of the following:

[0303] (i) The adhesive preferably has a tensile strength of at least about 1 MPa, more preferably at least about 5

[0304] MPa, even more preferably at least about 7 MPa, even more preferably at least about 10 MPa;

[0305] (ii) preferably has a Young's modulus of at least about 1 MPa;

[0306] (iii) preferably an NCO to OH index of at least about 80 to 130, more preferably at least about 100, even more preferably at least about 110, and further preferably no more than about 125;

[0307] as well as

[0308] (iv) combinations thereof.

[0309] A seventeenth aspect is applicable to the adhesive of aspect 16, wherein the second polyol comprises a polyoxyalkylene polyol having a hydroxyl number of at least about 15 mg KOH / g, preferably at least about 17 mg KOH / g, more preferably no more than about 30 mg KOH / g, and even more preferably no more than about 25 mg KOH / g; and / or a monoether comprising a poly(propylene glycol) monoether, preferably poly(propylene glycol) monobutyl ether.

[0310] In the eighteenth aspect, the adhesive of any one of aspects 16 or 17, based on the curing agent second component, the concentration of the monoether is no more than about 25 wt%, preferably about 0.5 to 20 wt%, even more preferably about 1 to 15 wt%, more preferably about 3 to 12 wt%.

[0311] The nineteenth aspect is applicable to any one of the aforementioned aspects 16 to 18, wherein the concentration of the second polyol is no more than 60 wt%, preferably no more than about 50 wt%, more preferably about 10 to 40 wt%, and even more preferably about 15 to 35 wt%, based on the weight of the second component of the curing agent.

[0312] In a twentieth aspect, the two-part adhesive of any one of the foregoing aspects 16 to 19, wherein the curing agent second component further comprises a third polyol having a number average molecular weight of at least about 4000 Daltons.

[0313] The twenty-first aspect is applicable to the two-component adhesive composition of any one of the aforementioned aspects 16 to 20. In the twenty-first aspect, the second curing agent component further comprises a diol or a triol, preferably a primary diol.

[0314] Regarding the twenty-second aspect, the two-component adhesive composition of any one of the aforementioned aspects 16 to 21 includes less than 1 wt% of a plasticizer, and preferably contains no plasticizer.

[0315] In the twenty-third aspect, the two-component adhesive of any one of aspects 16 to 22, the volume ratio of the NCO prepolymer to the curing agent second component includes about 1:10 to about 10:1, and preferred volume ratios may include about 1:1, at least about 1.5:1, at least about 4:1 and at least about 1:2.

[0316] A twenty-fourth aspect includes a laminate comprising a first substrate and a second substrate and the adhesive of any of aspects 16 to 23 sandwiched between the first substrate and the second substrate, wherein the coefficient of thermal expansion of the first substrate differs from the coefficient of thermal expansion of the second substrate by at least about 5%, preferably at least about 10%, and more preferably at least about 15%, measured in the temperature range of about -30°C to about 82°C.

[0317] A twenty-fifth aspect applies to the laminate of aspect 24, wherein the laminate does not contain a sufficient amount of primer to aid in bonding of the adhesive to either the first substrate and the second substrate.

[0318] Aspect twenty-six relates to any one of aspects 24 and 25, wherein the first substrate comprises one of the following: metal, coated metal, thermoplastic, composite material, preferably the composite material comprises carbon fiber, sheet molded composite material, preferably the metal may comprise at least one of aluminum, steel, stainless steel, galvanized steel, carbon steel and alloys thereof, preferably the thermoplastic comprises at least one of polyamide, polyolefin and combinations thereof, preferably the coating of the coated metal comprises nickel, preferably the polyolefin may comprise polycarbonate, polyethylene terephthalate, polybutylene terephthalate and combinations thereof.

[0319] A twenty-seventh aspect includes a method for preparing a laminate. The method comprises the following steps:

[0320] a. The adhesive of any one of aspects 16 to 23 is applied to either the first substrate or the second substrate;

[0321] b. bonding the first substrate to the second substrate,

[0322] The thermal expansion coefficient of the first substrate differs from the thermal expansion coefficient of the second substrate by at least about 5%.

[0323] In a twenty-eighth aspect, the method of aspect 27 does not include the step of applying a primer to either the first substrate or the second substrate, preferably both the first substrate and the second substrate.

[0324] In a twenty-ninth aspect, the method of any of aspects 27 or 28 does not include the step of mechanically pre-treating either the first substrate or the second substrate, preferably both the first substrate and the second substrate, prior to applying the adhesive.

[0325] The thirtieth aspect is applicable to any one of aspects 27 to 29, wherein the method further comprises the step of curing the adhesive at a temperature of less than about 140°C, preferably less than 120°C, also preferably less than about 105°C, more preferably less than about 100°C, even more preferably less than about 90°C, and further preferably less than about 80°C.

[0326] Aspect thirty-first applies to any of aspects 16 to 23, wherein the number average molecular weight of the second polyol comprises at least about 10,000 Daltons, preferably at least about 20,000 Daltons, more preferably at least about 35,000 Daltons, even more preferably at least about 50,000 Daltons, and most preferably at least about 80,000 Daltons.

Claims

1. A two-component adhesive composition comprising: a. NCO prepolymers, NCO prepolymers comprising the reaction product of an isocyanate compound and a polyol, preferably the NCO% in the prepolymer is up to about 30%, more preferably about 1% to 20%, Even more preferably less than 20% to at least 10%, or about 1% to 10%, b. a second component comprising a second polyol, preferably having a number average molecular weight of at least about 2,000 Daltons, more preferably at least about 4,000 Daltons, even more preferably at least about 8,000 Daltons, and most preferably greater than 10,000 Daltons, c. a silane adhesion promoter selected from the group consisting of an isocyanurate-based silane adhesion promoter, an isocyanate-based silane adhesion promoter, and combinations thereof, the concentration of the silane adhesion promoter comprising about 0.1 to 10 wt %, and d. Optional components, the optional components may include one or more catalysts, preferably a tin catalyst; as well as The properties of the adhesive may include one or more of the following: (i) preferably the tensile strength of the adhesive comprises at least about 1 MPa, more preferably at least about 5 MPa, even more preferably at least about 7 MPa, even more preferably at least about 10 MPa; (ii) preferably has a Young's modulus of at least about 1 MPa to about 100 MPa, (iii) preferably an NCO to OH index of at least about 80 to 130, preferably at least about 100, more preferably at least about 110, and even more preferably no more than about 125; and (v) combinations thereof.

2. The adhesive of claim 1 , further comprising a fourth component selected from the group consisting of at least one of an epoxy-functional silane adhesion promoter, a polyether diamine, a monoether, and combinations thereof, wherein the concentration of the fourth component is no more than about 20 wt %, preferably at least about 0.5 wt %.

3. The adhesive according to claim 2, wherein the fourth component comprises a monoether, preferably the monoether comprises polypropylene glycol monobutyl ether.

4. The adhesive of any one of claims 1, 2 or 3, wherein the second polyol of the second component comprises a polymer-modified polyol, preferably a modified polyether polyol, and the concentration of the polymer-modified polyol is up to about 70 wt% of the second component.

5. The adhesive of any one of the preceding claims, further comprising a flame retardant package, wherein the flame retardant package comprises up to about 25 wt% of the adhesive composition.

6. The adhesive composition of any of the preceding claims, wherein the composition comprises less than about 10 wt %, preferably less than about 5 wt %, more preferably less than about 4 wt %, even more preferably less than about 2 wt %, and most preferably less than about 1 wt % of plasticizer.

7. The adhesive composition according to any one of the preceding claims, further comprising a tertiary amine, preferably the tertiary amine comprises at least one of the following: 1,4-diazabicyclo[2.2.2]octane solution, diazabicycloundecene, 1,4-diazabicyclooctane, and combinations thereof.

8. The adhesive composition of any of the preceding claims, further comprising a chain extender comprising a polyol having a functionality of at least 2, and preferably comprising no more than about 30% NCO% of the adhesive, more preferably no more than about 25%, even more preferably no more than about 20% by weight, and most preferably at least about 10%.

9. A laminate comprising a first substrate and a second substrate and the adhesive of any of the preceding claims sandwiched between the first substrate and the second substrate, wherein the coefficient of thermal expansion of the first substrate differs from the coefficient of thermal expansion of the second substrate by at least about 5%, preferably at least about 10%, and more preferably at least about 15%, measured in the temperature range of about -30°C to about 82°C.

10. The laminate of claim 9, wherein the laminate does not contain a sufficient amount of primer to aid in bonding the adhesive to either the first substrate or the second substrate.

11. The laminate according to any one of claims 9 or 10, wherein the first substrate comprises one of the following: metal, coated metal, thermoplastic, composite material, preferably the composite material comprises carbon fiber, sheet molding composite material, preferably the metal may comprise at least one of aluminum, steel, stainless steel, galvanized steel, carbon steel and alloys thereof, preferably the thermoplastic comprises at least one of polyamide, polyolefin and combinations thereof, preferably the coating of the coated metal comprises nickel, preferably the polyolefin comprises polycarbonate, polyethylene terephthalate, polybutylene terephthalate and combinations thereof.

12. A method for preparing a laminated product, comprising a. The adhesive of any one of claims 1-8 is applied to either a first substrate or a second substrate; b. bonding the first substrate to the second substrate, The thermal expansion coefficient of the first substrate differs from the thermal expansion coefficient of the second substrate by at least about 5%, measured in a temperature range of about -30°C to about 82°C.

13. The method of claim 12, excluding the step of applying a primer to either the first substrate or the second substrate, preferably to both the first substrate and the second substrate.

14. The method according to any one of claims 12 or 13, excluding the step of mechanically pre-treating either the first substrate or the second substrate, preferably both the first substrate and the second substrate, before applying the adhesive.

15. The method according to any one of claims 12 to 14, further comprising curing the adhesive at a temperature below about 140°C, preferably below about 120°C, also preferably below about 105°C, more preferably below about 100°C, even more preferably below about 90°C, and further preferably below about 80°C.

16. The two-component adhesive according to any one of claims 1 to 8, wherein the second polyol of the second component comprises a curing agent, and the volume ratio of the NCO prepolymer to the curing agent comprises about 1:10 to about 10:1, and preferred volume ratios may include about 1:1, at least about 1.5:1, at least about 4:1, and at least about 2:1.

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