Composition

Abstract

This invention provides a kit and a method for preparing a urethane adhesive that can be easily prepared and exhibits high adhesive strength and flexible adhesive properties. [Solution] The urethane adhesive preparation kit according to the present invention is a kit comprising a first composition and a second composition, wherein the first composition contains a compound (A1) having two or more hydroxyl groups and two or more urea structures, and a compound (A2) having two or more hydroxyl groups, and the second composition contains a compound (B1) having two or more isocyanate groups.

Description

[Technical Field]

[0001] The present invention relates to a urethane adhesive preparation kit and a method for preparing a urethane adhesive. [Background technology]

[0002] For products involving movement or motion, such as automobiles, ships, and aircraft, reducing weight minimizes energy loss and ultimately leads to a reduction in carbon dioxide emissions. Therefore, multi-material technology, which involves bonding and joining different materials for the purpose of weight reduction, is attracting attention.

[0003] In multi-material applications, materials with different coefficients of thermal expansion, such as resin and metal, are bonded and joined together. When using materials with such differing coefficients, temperature changes can concentrate stress on the bonding surface, raising concerns about rupture of the adhesive layer or a decrease in durability. To address this challenge, an adhesive that balances both bonding strength and flexibility is essential.

[0004] Conventional adhesives incorporate chemical crosslinking using three or more reactive groups to improve adhesive strength, but this chemical crosslinking tends to impair flexibility. On the other hand, the technologies described in Patent Documents 1 and 2 attempt to achieve both adhesive strength and flexibility by introducing physical crosslinking using the high hydrogen bonding properties of urea groups. However, when using polyamines, as in the technology of Patent Document 1, the high reactivity of isocyanate-amines causes a rapid increase in viscosity during mixing, and the technology of Patent Document 2 requires complicated synthesis, among other problems. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-055921 [Patent Document 2] Japanese Patent Publication No. 2023-170895 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Some aspects of the present invention provide a kit and a method for preparing a urethane adhesive that can be easily prepared and exhibits high adhesive strength and flexible adhesive properties. [Means for solving the problem]

[0007] One embodiment of the urethane adhesive preparation kit according to the present invention is: A kit comprising a first composition and a second composition for preparing a urethane adhesive, The first composition contains a compound (A1) having two or more hydroxyl groups and two or more urea structures, and a compound (A2) having two or more hydroxyl groups. The second composition contains a compound (B1) having two or more isocyanate groups.

[0008] In one embodiment of the urethane adhesive preparation kit, When the content of compound (A1) is MA1 [parts by mass] and the content of compound (A2) is MA2 [parts by mass], MA1 / MA2 = 0.01 to 0.23 may be used.

[0009] In one embodiment of the urethane adhesive preparation kit, The compound (A1) may further have an ester structure.

[0010] In one embodiment of the urethane adhesive preparation kit, The compound (A1) may be a compound represented by the following general formula (1). HO-R 1 -NHCONH-R 2 -NHCONH-R 1 -OH ····(1) (In equation (1), there are multiple R 1 and R 2 (Each of these independently represents a divalent organic group.)

[0011] One aspect of the method for preparing the urethane adhesive according to the present invention is using the kit for preparing the urethane adhesive according to any of the above aspects, and mixing 100 to 250 parts by mass of the first composition with respect to 100 parts by mass of the second composition.

Effect of the Invention

[0012] According to the kit for preparing the urethane adhesive and the method for preparing the urethane adhesive according to the present invention, a urethane adhesive having high adhesive strength and flexible adhesive properties can be easily prepared.

Mode for Carrying Out the Invention

[0013] Hereinafter, preferred embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments, and also includes various modified examples implemented within the scope not changing the gist of the present invention.

[0014] In this specification, the numerical range described using "X to Y" means including the numerical value X as the lower limit value and including the numerical value Y as the upper limit value.

[0015] 1. Kit for Preparing Urethane Adhesive The kit for preparing the urethane adhesive according to an embodiment of the present invention (hereinafter, also simply referred to as "kit") is composed of a first composition and a second composition. The first composition contains a compound (A1) having two or more hydroxyl groups and two or more urea structures (hereinafter, also referred to as "compound (A1)") and a compound (A2) having two or more hydroxyl groups (hereinafter, also referred to as "compound (A2)"). The second composition is characterized by containing a compound (B1) having two or more isocyanate groups (hereinafter, also referred to as "compound (B1)"). Hereinafter, each kit configuration will be described in detail.

[0016] 1.1. First Composition The first composition comprising the kit according to this embodiment contains a compound (A1) having two or more hydroxyl groups and two or more urea structures, and a compound (A2) having two or more hydroxyl groups.

[0017] 1.1.1.Compound (A1) The first composition contains a compound (A1) having two or more hydroxyl groups and two or more urea structures. Compounds (A1) and (A2) in the first composition react with compound (B1) in the second composition when the first composition is mixed with the second composition to produce polyurethane, which can form an adhesive layer with excellent flexibility.

[0018] Compound (A1) has two or more urea structures within its molecule, which allows for the introduction of urea structures into the resulting polyurethane. The urea structures introduced into the polyurethane can then form hydrogen bonds, thereby improving the adhesive strength.

[0019] Compound (A1) may further possess an ester structure. By having an ester structure within the molecule, compound (A1) can introduce this ester structure into the resulting polyurethane. The ester structure introduced into the polyurethane can then form hydrogen bonds, improving adhesion.

[0020] Compound (A1) may further contain a urethane structure. By having a urethane structure within the molecule, a large amount of urethane structure can be introduced into the resulting polyurethane. The urethane structure, urea structure, and ester structure introduced into the polyurethane can be tightly hydrogen-bonded, thereby improving adhesion.

[0021] Compound (A1) is not particularly limited as long as it is a compound having two or more hydroxyl groups and two or more urea structures, but it is preferably a compound represented by the following general formula (1). HO-R 1 -NHCONH-R 2 -NHCONH-R 1 -OH ····(1) (In formula (1), a plurality of R 1 and R 2 each independently represent a divalent organic group.)

[0022] R 2 preferably has a structure having a urethane bond (-NHCOO-), and more preferably has a structure having a plurality of urethane bonds. When R 2 has a structure having a plurality of urethane bonds, R 2 is preferably a structure represented by the following general formula (2). *-[R 4 -(NHCOO-R 5 -COONH)-R 4 n -* ····(2) (In formula (2), a plurality of R 4 and R 5 each independently represent a divalent organic group, n is an integer of 1 or more, and * represents a bond.)

[0023] When compound (A1) has an ester structure, R 5 in the above general formula (2) preferably has an ester structure.

[0024] When compound (A1) is a compound represented by the above general formula (1), compound (A1) can be produced by reacting a compound represented by the following general formula (3) with a compound represented by the following general formula (4). OCN-R 2 -NCO ····(3) [[ID=*47]]HO-R 1 -NH2····(4) (In formulas (3) and (4), R 1 and R 2 are synonymous with R 1 , R 2 in the above formula (1).)

[0025] As the compound represented by the above general formula (3), a compound having a plurality of isocyanate groups, a polyurethane having a plurality of isocyanate groups at the terminal, etc. can be preferably used.It should be noted that there seems to be a small error in the original text where in the formula (4) in line 47, it should be "HO-R" instead of "*47 HO-R". This has been corrected in the translation.

[0026] Examples of compounds having multiple isocyanate groups include aliphatic polyisocyanates such as 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, and lysine methyl ester diisocyanate; alicyclic polyisocyanates such as 1,3-bis(isocyanatomethyl)cyclohexane, hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate (IPDI), and hydrogenated tolylene diisocyanate; and aromatic polyisocyanates such as tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), naphthylene diisocyanate, xylylene diisocyanate (XDI), triphenylmethane triisocyanate, and tris(4-phenylisocyanate) thiophosphate. Furthermore, examples include adduct compounds obtained by reacting MDI, TDI, HDI, XDI, IPDI, etc. with divalent or trivalent polyhydric alcohols, biuret compounds of HDI and IPDI, urethidion compounds of TDI, etc., and isocyanurate compounds of TDI, HDI, IPDI, etc. Two or more of these compounds can also be used in mixture form. Of these, aliphatic polyisocyanates are preferred in terms of pot life.

[0027] Known polyurethanes can be used as polyurethanes having multiple isocyanate groups at their ends. Organic polyol compounds commonly used in the manufacture of polyurethane can be used as raw materials. Examples of organic polyol compounds include polyether polyols, polyester polyols, polyether ester polyols, and polycarbonate polyols. Among these, polyester polyols are particularly preferred. These organic polyol compounds can be used individually or in combination of two or more.

[0028] Examples of polyether polyols include those obtained by polymerization of alkylene oxides, either alone or copolymerized. Specific examples of polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol.

[0029] Polyester polyols include those obtained by condensation polymerization of dibasic acids (e.g., succinic acid, glutaric acid, adipic acid, sebacic acid, fumaric acid, maleic acid, phthalic acid, etc.) or their anhydrides with glycols (e.g., aliphatic glycols such as ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripylene glycol, butanediol, pentanediol, hexanediol, octanediol, nonanediol; alicyclic glycols such as bishydroxymethylcyclohexane; aromatic glycols such as xylylene glycol; alkyldialkanolamines such as C1-C18 alkyldiethanolamines, etc.). Specific examples of polyester polyols include condensation-type polyester polyols such as polyethylene adipate, polybutylene adipate, and polyhexamethylene adipate, or lactone-based polyester diols such as polylactone diol, polycaprolactone diol, and polymethylvalerolactone diol, obtained by ring-opening polymerization of lactones using diols as initiators.

[0030] Examples of polyether ester polyols include those obtained by reacting a mixture of an ether group-containing diol or other glycol with a dicarboxylic acid or its anhydride, or by reacting a polyester glycol with an alkylene oxide. Specific examples of polyether ester polyols include poly(polytetramethylene ether) adipate.

[0031] Specific examples of polycarbonate polyols include those obtained by transesterification of carbonates such as diphenyl carbonate, diethyl carbonate, and ethylene carbonate with polyhydric alcohols such as hexamethylene glycol and 3-methyl-1,5-pentanediol.

[0032] Examples of organic polyisocyanate compounds used as raw materials for preparing polyurethanes having multiple isocyanate groups at their ends include 2,4- or 2,6-tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, methylene diisocyanate, isopropyl diisocyanate, lysine diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate, and isopropylidene dicyclohexyl-4,4'-diisocyanate. These organic polyisocyanate compounds can be used individually or in combination of two or more.

[0033] Polyurethanes having multiple isocyanate groups at their ends can be produced by methods described, for example, in Japanese Patent Publication No. 10-130615. Specifically, the above organic Polyurethanes having multiple isocyanate groups at their ends can be produced by reacting a polyol compound with an organic polyisocyanate compound at a temperature of 10 to 150°C, using a solvent that is inert to the isocyanate groups as needed, and a urethane catalyst if necessary.

[0034] When producing polyurethane having multiple isocyanate groups at its ends, it is preferable that the ratio of the organic polyol compound to the organic polyisocyanate compound is such that the NCO / OH ratio, which is the ratio of the equivalent amount of isocyanate groups in the organic polyisocyanate compound to the equivalent amount of hydroxyl groups in the organic polyol compound, is in the range of 2 to 20.

[0035] As the compound represented by the above general formula (4), alkanolamines are preferred. As alkanolamines, alkanol monoamines such as monoethanolamine, mono-n-butylethanolamine, 2-(4-aminophenyl)ethyl alcohol, trishydroxymethylaminomethane, 2-amino-2-methyl-1-propanol, 1-amino-2-propanol, 3-amino-1,2-propanediol, 2-amino-1-butanol, 1-amino-2-butanol, 5-amino-1-pentanol, and 2-(2-aminoethoxy)ethanol can be used; and alkanol diamines such as N-(β-aminoethyl)ethanolamine, 3,5-diaminobenzyl alcohol, and 1,3-diamino-2-propanol can be used. Among these, alkanol monoamines are preferred, and 2-(2-aminoethoxy)ethanol is particularly preferred from the viewpoint of the crystallinity and solubility of the resulting ureadiol.

[0036] The content of compound (A1) in the first composition is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and particularly preferably 2.0% by mass or more. The content of compound (A1) in the first composition is preferably 50.0% by mass or less, more preferably 30.0% by mass or less, and particularly preferably 20.0% by mass or less. By setting the content of compound (A1) within the above range, the strength of the adhesive layer can be further improved.

[0037] 1.1.2.Compound (A2) The second composition contains compound (A2) having two or more hydroxyl groups. Compounds (A1) and (A2) in the first composition react with compound (B1) in the second composition when the first and second compositions are mixed to produce polyurethane, forming an adhesive layer with excellent flexibility. Note that compounds (A1) and (A2) are different components, and compound (A2) does not have a urea structure.

[0038] The number of hydroxyl groups in compound (A2) is preferably 2 to 20, more preferably 2 to 10, and particularly preferably 2 to 4. By keeping the number of hydroxyl groups in compound (A2) within the above range, the strength of the formed adhesive layer can be further improved.

[0039] Examples of compound (A2) include polyhydric alcohols and polyol compounds. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, and alkanediols such as 2-butyl-2-ethyl-1,3-propanediol; alkanediols such as 1,2,4-butanetriol and trimethylolpropane; and alkanetetraols such as pentaerythritol. Examples of polyol compounds include polyether polyols, polyester polyols, polybutadiene polyols, and polycarbonate polyols.

[0040] Examples of polyether polyols include polyalkylene glycol, polyalkylene glycol-containing polyol, and bisphenol-containing polyol. Examples of polyglycols include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Examples of bisphenol-containing polyols include propylene glycol adducts of bisphenol A and ethylene glycol adducts of bisphenol A.

[0041] Examples of polyester polyols include condensed polyester polyols and polylactone polyols.

[0042] Examples of condensed polyester polyols include polyester polyols formed from polycarboxylic acids, their esters or anhydrides, and polyhydric alcohol compounds. Examples of polycarboxylic acids include aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, and cyclohexane-1,4-dicarboxylic acid; and aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, trimellitic acid, and pyromellitic acid. Examples of polyhydric alcohol compounds include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, ethylene oxide or propylene oxide adducts of bisphenol A, and glycerin.

[0043] Examples of polylactone polyols include polycaprolactone diol, polycaprolactone triol, and polyvalerolactone diol.

[0044] Examples of polybutadiene polyols include poly(1,4-butadiene) glycol or its hydrogenated derivatives, poly(1,2-butadiene) glycol or its hydrogenated derivatives, and poly(1,2- / 1,4-butadiene) glycol or its hydrogenated derivatives.

[0045] Examples of polycarbonate polyols include polytetramethylene carbonate diol, polypentamethylene carbonate diol, polyhexamethylene carbonate diol, and polyhexamethylene carbonate triol.

[0046] Among these compounds (A2), polyether polyols, polyester polyols, or polycarbonate polyols are preferred, with polyester polyols or polycarbonate polyols being more preferred. When compound (A2) is an oligomer or polymer, the number average molecular weight of compound (A2) is preferably 300 or more, more preferably 350 or more, and particularly preferably 400 or more. Furthermore, the number average molecular weight of compound (A2) is preferably 6000 or less, more preferably 5000 or less, and particularly preferably 4500 or less.

[0047] The ratio of the number of hydroxyl groups in compound (A1) and compound (A2) to the number of isocyanate groups in compound (B1) is preferably 0.9 or higher, more preferably 1.0 or higher, and particularly preferably 1.2 or higher. By keeping the ratio within the above range, polyurethane is more effectively produced from compound (A1) and compound (A2) and compound (B1), thereby further improving the flexibility of the adhesive layer. Here, the number of isocyanate groups in compound (B1) refers to the weighted average value of the number of isocyanate groups in compound (B1) in the second composition. Also, the number of hydroxyl groups in compound (A1) and compound (A2) refers to the weighted average value of the number of hydroxyl groups in compound (A1) and compound (A2) in the first composition.

[0048] The content of compound (A2) in the first composition is preferably 30% by mass or more, Preferably, the content is 40% by mass or more, and particularly preferably 50% by mass or more. The content of compound (A2) in the first composition is preferably 99.9% by mass or less, more preferably 99.0% by mass or less, even more preferably 90.0% by mass or less, and particularly preferably 80.0% by mass or less. By setting the content of compound (A1) within the above range, the flexibility of the adhesive layer can be further improved.

[0049] When the content of compound (A1) in the first composition is MA1 [parts by mass] and the content of compound (A2) is MA2 [parts by mass], the mass ratio MA1 / MA2 is preferably 0.01 or more, more preferably 0.02 or more, and particularly preferably 0.03 or more. MA1 / MA2 is preferably 0.23 or less, more preferably 0.20 or less, and particularly preferably 0.18 or less. When MA1 / MA2 is within the above range, it is easier to obtain an adhesive layer with an excellent balance of high adhesive strength and flexibility.

[0050] 1.1.3. Other Additives The first composition may contain additives such as a urethane catalyst, inorganic filler, plasticizer, colorant, and dehydrating agent. Each of these additives may be used individually or in combination of two or more.

[0051] 1.1.3.1. Urethane-based catalyst The urethane catalyst can promote the urethane reaction between compound (A1) and compound (A2) and compound (B1) when mixing the first composition and the second composition to prepare a urethane adhesive.

[0052] Examples of urethane catalysts include tertiary amines, quaternary ammonium salts, carboxylates, and organometallic compounds. Examples of tertiary amines include 1,4-diazabicyclo[2.2.2]octane, diazabicycloundecene, bis(N,N-dimethylamino-2-ethyl) ether, N,N,N',N'-tetramethylhexamethylenediamine, and N-methylmorpholine. Examples of quaternary ammonium salts include tetraethylammonium hydroxide. Examples of carboxylates include potassium acetate and potassium octoate.

[0053] Examples of organometallic compounds include organotin compounds such as tin acetate, tin octoate, tin oleate, tin laurate, dibutyltin diacetate, dimethyltin dilaurate, dibutyltin dilaurate, dibutyltin dimercaptide, dibutyltin maleate, dibutyltin dilaurate, dibutyltin dineodecanoate, dioctyltin dimercaptide, dioctyltin dilaurylate, and dibutyltin dichloride; organolead compounds such as lead octanoate and lead naphthenate; organonickel compounds such as nickel naphthenate; organocobaltan compounds such as cobalt naphthenate; organocupend compounds such as copper octate; and organobismuth compounds such as bismuth octoate.

[0054] If the first composition contains a urethane catalyst, the content of the urethane catalyst in the first composition is preferably 0.01% by mass or more, and more preferably 0.1% by mass. The content of the urethane catalyst in the first composition is preferably 10% by mass or less, and more preferably 5% by mass or less. When the content of the urethane catalyst is within the above range, the reaction between compound (A1) and compound (A2) and compound (B1) can be effectively promoted. Note that one type of urethane catalyst or two or more types may be used.

[0055] 1.1.3.2. Inorganic fillers Inorganic fillers can improve the strength of the adhesive layer obtained by mixing the first and second compositions, and can also impart heat resistance. Examples of such inorganic fillers include alumina, silica, titanium dioxide, calcium carbonate, and talc.

[0056] If the first composition contains an inorganic filler, the inorganic filler content in the first composition is preferably 5% by mass or more, and more preferably 10% by mass. The inorganic filler content in the first composition is preferably 50% by mass or less, and more preferably 40% by mass or less. When the inorganic filler content is within the above range, the strength of the adhesive layer can be effectively improved. Note that the inorganic filler may be used alone or in combination of two or more types.

[0057] 1.1.3.3. Plasticizers Examples of plasticizers that can be used include phthalate esters such as dibutyl phthalate, di(2-ethylhexyl) phthalate, and butyl benzyl phthalate; non-aromatic dibasic acid esters such as dioctyl adipate and dioctyl sebacate; benzoic acid esters such as dipropylene glycol dibenzoate and triethylene glycol dibenzoate; and adipate esters such as diisononyl adipate, dioctyl adipate, and diisodecyl adipate.

[0058] 1.1.3.4. Colorants As a coloring agent, known coloring agents such as carbon black can be used.

[0059] 1.1.3.5. Dehydrating agent The inclusion of a dehydrating agent in the first composition suppresses foaming that is likely to occur when mixed with the second composition, and also suppresses the shortening of the pot life due to humidity in the atmosphere during the open time after mixing and coating.

[0060] Examples of dehydrating agents include inorganic dehydrating agents and organic dehydrating agents, but inorganic dehydrating agents are preferred. Examples of inorganic dehydrating agents include zeolites such as zeolite 3A, zeolite 4A, and zeolite 5A; anhydrous inorganic salts such as anhydrous calcium chloride, anhydrous sodium sulfate, anhydrous calcium sulfate, anhydrous magnesium chloride, anhydrous magnesium sulfate, anhydrous potassium carbonate, anhydrous potassium sulfide, anhydrous potassium sulfite, anhydrous sodium sulfite, and anhydrous copper sulfate; and known inorganic dehydrating agents such as silica gel, alumina, silica alumina, and activated clay can be used. Among these, zeolites are more preferred, and zeolite 3A and zeolite 5A are particularly preferred.

[0061] Examples of organic dehydrating agents include orthoformate esters such as methyl orthoformate, ethyl orthoformate, and propyl orthoformate; orthoacetate esters such as methyl orthoacetate, ethyl orthoacetate, and propyl orthoacetate; orthopropionate esters such as methyl orthopropionate and ethyl orthopropionate; benzaldehyde dimethyl acetal, acetaldehyde dimethyl acetal, formaldehyde dimethyl acetal, acetone dimethyl acetal, acetone dibenzyl acetal, diethyl ketone dimethyl acetal, and benzo Known organic dehydrating agents such as acetal compounds including phenone dimethyl acetal, benzyl phenyl ketone dimethyl acetal, cyclohexanone dimethyl acetal, acetophenone dimethyl acetal, 2,2-dimethoxy-2-phenylacetophenone, 4,4-dimethoxy-2,5-cyclohexadiene-1-one acetal, and dimethylacetamidodiethyl acetal; carbodiimide compounds including dicyclohexylcarbodiimide and diisopropylcarbodiimide; and silicate compounds including methyl silicate and ethyl silicate can be used.

[0062] 1.2. Second composition The second composition contains a compound (B1) having two or more isocyanate groups.

[0063] 1.2.1.Compound (B1) Compound (B1) in the second composition is obtained by mixing the first composition and the second composition. Compounds (A1) and (A2) in composition 1 react to produce polyurethane, which can form an adhesive layer with excellent flexibility.

[0064] Compound (B1) may be a low molecular weight compound, an oligomer, or a polymer. The number of isocyanate groups in compound (B1) is preferably 2 to 20, more preferably 2 to 10, even more preferably 2 to 6, even more preferably 2 to 4, and particularly preferably 2 or 3.

[0065] Examples of compound (B1) include aromatic polyisocyanates or aliphatic polyisocyanates, and prepolymers having multiple isocyanate groups at their ends, which are reaction products of these polyisocyanates with polyols.

[0066] Examples of aromatic polyisocyanates include aromatic diisocyanates such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), and carbodiimide-modified diphenylmethane diisocyanate (carbodiimide-modified MDI, di(isocyanatophenylmethylphenyl)carbodiimide); aromatic triisocyanates such as triphenylmethane triisocyanate and dimethylene triphenylene triisocyanate; aromatic tetraisocyanates such as benzene-1,2,4,5-tetraisocyanate; and mixtures of aromatic polyisocyanates having 2 to 4 NCOs, such as polymethylene polyphenylene polyisocyanate (crude MDI).

[0067] Examples of aliphatic polyisocyanates include tetramethylene diisocyanate, hexamethylene diisocyanate, undecane diisocyanate, dodecane diisocyanate, tridecane diisocyanate, methylenedi(1,4-cyclohexylene isocyanate), isophorone diisocyanate, cyclohexane-1,4-diisocyanate, tri(1,4-cyclohexylene) diisocyanate, propylene-1,3-di(1,4-cyclohexylene isocyanate), norbornene diisocyanate (NBDI), m-xylene diisocyanate, and other aliphatic diisocyanates. Examples include cyanates; aliphatic triisocyanates such as 1,3,6-hexamethylene triisocyanate, 1,6,11-undecane triisocyanate, cyclohexane-1,3,5-triisocyanate, and tricyclohexylmethane triisocyanate; aliphatic trifunctional isocyanates such as trimers (isocyanurates), burettes, allophanate bonds, and adducts of aliphatic diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate; and aliphatic tetraisocyanates such as cyclohexane-1,2,4,5-tetraisocyanate.

[0068] Examples of polyols used in forming prepolymers having multiple isocyanate groups at their ends, which are reaction products of aromatic polyisocyanates or aliphatic polyisocyanates with polyols, include the polyol compounds exemplified above as compound (A1) and compound (A2).

[0069] Examples of commercially available compounds (B1) include "WANNATE PM-200" (crude MDI) and "WANNATE CDMDI" (carbodiimide-modified MDI) from WANHUA, "DURANET TPA-100" (isocyanurate of hexamethylene diisocyanate) from Asahi Kasei, and "TAKENATE 500" (m-xylene diisocyanate) from Mitsui Chemicals.

[0070] The content of compound (B1) in the second composition is preferably 30% by mass or more, more preferably 40% by mass or more, and particularly preferably 50% by mass or more. The content of compound (B1) in the second composition is preferably 99.9% by mass or less, more preferably 95.0% by mass or less, even more preferably 90.0% by mass or less, and particularly preferably The content is 80.0% by mass or less. By keeping the content of compound (B1) within the above range, the flexibility of the adhesive layer can be improved. Compound (B1) may be used alone or in combination of two or more types.

[0071] 1.2.2. Other Additives The second composition may contain additives such as dehydrating agents, inorganic fillers, and plasticizers. These additives may be used individually or in combination of two or more.

[0072] 1.2.2.1. Dehydrating agent The second composition contains a dehydrating agent, which allows for the removal of moisture that may be introduced from outside the system during storage. This further improves the storage stability of the second composition, and consequently, the storage stability of the urethane adhesive preparation kit.

[0073] Examples of dehydrating agents include inorganic dehydrating agents and organic dehydrating agents, but inorganic dehydrating agents are preferred. Specific examples of inorganic and organic dehydrating agents are those exemplified in section "1.1.3.5. Dehydrating Agents," respectively.

[0074] The content of the dehydrating agent in the second composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more. The content of the dehydrating agent in the second composition is preferably 20% by mass or less, and more preferably 10% by mass or less. When the content of the dehydrating agent is within the above range, the storage stability of the second composition can be further improved.

[0075] The ratio MD / MB1, which is the ratio of the mass of the dehydrating agent (MD) to the mass of compound (B1) (MB1) in the second composition, is preferably 0.10 or higher, more preferably 0.15 or higher, even more preferably 0.22 or higher, and particularly preferably 0.25 or higher. When MD / MB1 is within the above range, the storage stability of the second composition can be further improved.

[0076] 1.2.2.2. Inorganic fillers As inorganic fillers, the same compounds and their proportions as those described in section "1.1.3.2. Inorganic Fillers" can be used.

[0077] 1.2.2.3. Plasticizers As a plasticizer, compounds similar to those described in section "1.1.3.3. Plasticizers" can be used.

[0078] 2. Method for preparing urethane adhesive A method for preparing a urethane adhesive according to one embodiment of the present invention is: A step of preparing a urethane adhesive kit comprising: a first composition containing a compound (A1) having two or more hydroxyl groups and two or more urea structures and a compound (A2) having two or more hydroxyl groups, and a second composition containing a compound (B1) having two or more isocyanate groups; Using the urethane adhesive preparation kit, the process involves mixing 100 to 250 parts by mass of the first composition with 100 parts by mass of the second composition, Includes.

[0079] In the step of mixing the first composition and the second composition, it is preferable to mix 100 to 250 parts by mass of the first composition with 100 parts by mass of the second composition, and more preferably 110 to 220 parts by mass of the first composition.

[0080] Furthermore, when preparing a urethane adhesive by mixing the first composition and the second composition, it is preferable to mix the first and second compositions so that the value of (number of isocyanate groups in the compound contained in the second composition) / (number of hydroxyl groups in the compound contained in the first composition) is 1 to 1.8, and more preferably 1 to 1.5. When the value of (number of isocyanate groups in the compound contained in the second composition) / (number of hydroxyl groups in the compound contained in the first composition) is within the above range, the water resistance performance can be further enhanced. Also, when the value of (number of isocyanate groups in the compound contained in the second composition) / (number of hydroxyl groups in the compound contained in the first composition) is within the above range, changes in physical properties after initial curing can be further suppressed.

[0081] When using a urethane adhesive, the first composition and the second composition are first mixed to prepare the urethane adhesive during the bonding operation. After applying the obtained urethane adhesive to one of the adherends, the other adherend is placed on top of the applied urethane adhesive so that it is in close contact with the adhesive, thereby forming an adhesive layer between the two adherends and achieving bonding. Alternatively, the urethane adhesive may be applied to both adherends, and then the applied urethane adhesives may be brought into close contact with each other. Thus, according to the method for preparing the urethane adhesive in this embodiment, the urethane adhesive can be easily prepared and adherends can be effectively bonded together.

[0082] The thickness of the adhesive layer formed between the two adherends is preferably 0.01 mm or more, and more preferably 0.05 mm or more. The thickness of the adhesive layer formed between the two adherends is preferably 5 mm or less, and more preferably 3 mm or less.

[0083] The adhesive layer formed by applying the urethane adhesive contains polyurethane produced from a compound (A1) having two or more hydroxyl groups and two or more urea structures, a compound (A2) having two or more hydroxyl groups, and a compound (B1) having two or more isocyanate groups. Therefore, it has many hydrogen bonds derived from the urea structure, resulting in high adhesive strength and flexible adhesive properties.

[0084] 2. Examples The present invention will be described below with reference to examples, but the present invention is not limited in any way by these examples. In these examples, "parts" and "%" are based on mass unless otherwise specified.

[0085] 2.1. Example 1 2.1.1. Preparation of the first composition In a three-necked separable flask, 130.04 parts by mass of Kuraray Polyol P-4010 (manufactured by Kuraray Co., Ltd., product name "Kuraray Polyol P-4010", Mn=4000, hydroxyl value=28, acid value<0.5, linear liquid type polyester polyol) and 14.45 parts by mass of Kuraray Polyol F-1010 (manufactured by Kuraray Co., Ltd., product name "Kuraray Polyol F-1010", Mn=1,000, hydroxyl value=168, acid value<0.5, branched liquid trifunctional type polyester polyol) were added as compound (A2) having two or more hydroxyl groups. Furthermore, 2.28 parts by mass of 2-(2-aminoethoxy)ethanol (manufactured by Tokyo Chemical Industry Co., Ltd., product name "2-(2-aminoethoxy)ethanol") were added, and the mixture was stirred for 30 minutes under reduced pressure at 25°C.

[0086] Subsequently, 2.10 parts by mass of 1,3-bis(isocyanatomethyl)cyclohexane (manufactured by Mitsui Chemicals, product name "Takenate 600") were added, and the mixture was stirred at 25°C under a nitrogen atmosphere for 30 minutes to synthesize compound (A1) having two or more hydroxyl groups and two or more urea structures in situ. A mixture of compound (A1) and compound (A2) was then prepared.

[0087] Next, 25.42 parts by mass of NS100 (manufactured by Nitto Funka Kogyo Co., Ltd., product name "NS100", calcium carbonate) and 25.42 parts by mass of SOAP STONEA (manufactured by Nippon Mistron Co., Ltd., product name "SOAP STONEA", talc) were added as inorganic fillers. After further dehydration under reduced pressure at 120°C for 3 hours, the temperature was lowered to 80°C. 0.29 parts by mass of triethylenediamine (manufactured by Air Products & Chemicals, product name "TEDA") was added as a urethane catalyst, and the mixture was stirred under a nitrogen atmosphere for 30 minutes. Finally, degassing under reduced pressure was performed to obtain the first composition.

[0088] 2.1.2. Preparation of the second composition In a three-neck separable flask, 67.30 parts by mass of Kuraray Polyol P-4010 (manufactured by Kuraray Co., Ltd., product name "Kuraray Polyol P-4010", Mn=4000, hydroxyl value=28, acid value<0.5, linear liquid type polyester polyol) was added, 38.0 parts by mass of NS100 (manufactured by Nitto Funka Kogyo Co., Ltd., product name "NS100", calcium carbonate) was added as an inorganic filler, 14.0 parts by mass of Molecular Sieves 5A (manufactured by Union Showa Co., Ltd., product name "Molecular Sieves 5A") as a dehydrating agent, and 18.0 parts by mass of diisononyl adipate (manufactured by J-Plus Co., Ltd., product name "DINA") was added, and the mixture was uniformly stirred under reduced pressure at 25°C.

[0089] Subsequently, 62.7 parts by mass of Luplanate MP102 (manufactured by BASF INOAC Polyurethane Co., Ltd., product name "Luplanate MP102", aromatic isocyanate) was added, and the reaction was carried out at 80°C under reduced pressure for 2 hours to synthesize a compound (B1) having two or more isocyanate groups in situ, thereby obtaining the second composition.

[0090] 2.1.3. Preparation and Evaluation of Urethane Adhesives The shear adhesive strength, maximum breaking stress, maximum point strain, and elastic modulus of a urethane adhesive prepared using a urethane adhesive preparation kit comprising the first and second compositions as described below were evaluated by the following method.

[0091] [Preparation of urethane adhesive] The first composition and the second composition were weighed into polyethylene bags according to the mixing ratios shown in Table 1 below. After sealing the bags, they were rolled on the palm of the hand for 1 minute to mix and prepare a urethane adhesive.

[0092] [Evaluation of shear bond strength] The surface of a substrate (2.5cm x 10cm cation electrodeposited steel sheet) was cleaned beforehand using a paper wiper containing acetone (Kimwipes from Nippon Paper Crecia Co., Ltd.), and the urethane adhesive prepared above was applied to the substrate. Then, to ensure a uniform adhesive thickness, glass beads with a diameter of 0.25mm were placed between the two substrates, and another substrate was bonded to it so that the bonding area was 1.25cm x 2.5cm. The two substrates were then heated in a constant temperature bath at 120°C for 3 hours to prepare a test specimen for measuring shear bonding strength.

[0093] For the test specimens prepared as described above, the maximum breaking stress of the bonded joint was measured using a tensile testing machine (Shimadzu Corporation's "Autograph AG5000B") in accordance with JIS K6850, and evaluated as shear bond strength. The measurement conditions were: temperature: 23°C, chuck distance: 110 mm, test speed: 5 mm / min.

[0094] Shear bond strength is judged as "good" if it is 10 MPa or higher, as this indicates sufficient bond strength; "fairly good" if it is between 5 MPa and 10 MPa, as this indicates bond strength suitable for practical use; and "poor" if it is less than 5 MPa, as this indicates insufficient bond strength that makes it unsuitable for practical use.

[0095] [Evaluation of flexibility] The urethane adhesive prepared above was applied to a release PET film (manufactured by Panac Co., Ltd., model number "SP-01-75BU"), a 2 mm thick spacer was placed in between, and another release PET film was placed on top. The entire surface was pressed until the film thickness was uniform, forming it into a sheet, and then heated and cured in a constant temperature bath at 120°C for 3 hours. After that, the release PET film was peeled off to obtain the adhesive sheet, which was then cut into a No. 2 dumbbell shape (JIS-K6251) using a dumbbell cutter to prepare a test piece for flexibility measurement.

[0096] Using the flexibility test specimens prepared as described above, tensile tests were conducted using a tensile testing machine (Shimadzu Corporation's "Autograph AG5000B") until the resin fractured. The measurement conditions were: temperature: 23°C, chuck distance: 30 mm, test speed: 100 mm / min. The maximum load obtained until fracture was divided by the cross-sectional area at the center of the dumbbell-shaped specimen to determine the maximum point stress (MPa), the displacement at the fracture point was divided by the initial chuck distance of 30 mm and multiplied by 100 to determine the fracture point strain (%), and the slope of the stress immediately after the start of tensile testing was evaluated as the modulus of elasticity (MPa).

[0097] The maximum point stress of the adhesive layer is judged as "good" if it is 4 MPa or higher, indicating sufficient strength as an adhesive layer, and as "poor" if it is less than 4 MPa, indicating insufficient strength as an adhesive layer.

[0098] The fracture point strain of the adhesive layer is judged as "good" if it is 150% or more, because it can distribute the load on the adhesive layer due to ambient temperature changes and is less likely to fracture. If it is less than 150%, it is judged as "poor" because it is insufficient to distribute the load on the adhesive layer due to ambient temperature changes.

[0099] The elastic modulus of the adhesive layer is judged as "good" if it is between 0.1 MPa and less than 3 MPa, as it shows sufficient flexibility; "fairly good" if it is between 3 MPa and less than 10 MPa, as it can be used in practical applications; and "poor" if it is 10 MPa or more, as it lacks flexibility.

[0100] 2.2. Examples 2-5, Comparative Example 1 In Example 1 described above, the first composition and the second composition were prepared in the same manner as in Example 1, except that the types and amounts of each component were as shown in Table 1 below. Furthermore, the first composition and the second composition were mixed in the same manner as in Example 1 at the mixing ratio shown in Table 1 below to prepare a urethane adhesive, which was evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0101] 2.3. Evaluation Results Table 1 below shows the compositions of the first and second compositions used in Examples 1-5 and Comparative Example 1, the mixing ratio of the urethane adhesive, and the evaluation results for each.

[0102] [Table 1]

[0103] The following products or reagents were used for each component listed in Table 1 above. • 1,3-Bis(isocyanatomethyl)cyclohexane (manufactured by Mitsui Chemicals, product name "Takenate 600") • 2-(2-aminoethoxy)ethanol (manufactured by Tokyo Chemical Industry Co., Ltd., product name "2-(2-aminoethoxy)ethanol") • Kuraray Polyol P-4010 (manufactured by Kuraray Co., Ltd., product name "Kuraray Polyol P-4010", Mn=4000, hydroxyl value=28, acid value<0.5, linear liquid type polyester polyol) • Kuraray Polyol C-1090 (manufactured by Kuraray Co., Ltd., product name "Kuraray Polyol C-1090", Mn=1000, hydroxyl value=112, acid value<0.03, linear liquid type polyester polyol) • Sannix PP-400 (manufactured by Sanyo Chemical Industries, Ltd., product name "Sannix PP-400", Mn=400, hydroxyl value=280, acid value 0.03, linear liquid type polyether polyol) • Kuraray Polyol F-1010 (manufactured by Kuraray Co., Ltd., product name "Kuraray Polyol F-1010", Mn=1,000, hydroxyl value=168, acid value<0.5, branched liquid trifunctional polyester polyol) • NS100 (manufactured by Nitto Funka Kogyo Co., Ltd., product name "NS100", calcium carbonate, inorganic filler) • SOAP STONEA (manufactured by Nippon Mistron Co., Ltd., product name "SOAP STONEA", talc, inorganic filler) • Triethylenediamine (manufactured by Air Products & Chemicals, product name "TEDA", urethane (Tanification catalyst) • Luplanate MP102 (manufactured by BASF INOAC Polyurethane Co., Ltd., product name "Luplanate MP102", aromatic isocyanate) • Diisononyl adipate (manufactured by J-Plus Co., Ltd., product name "DINA", plasticizer) • Molecular Sieves 5A (manufactured by Union Showa Co., Ltd., product name "Molecular Sieves 5A", dehydrating agent)

[0104] According to the evaluation results in Table 1 above, the urethane adhesive preparation kits according to the present invention shown in Examples 1 to 5 were able to form adhesive layers exhibiting high adhesive strength and flexible adhesive properties, demonstrating excellent results.

[0105] In contrast, the urethane adhesive preparation kit shown in Comparative Example 1 was unsatisfactory because it did not contain the components necessary to synthesize compound (A1) in the first composition, and therefore could not form an adhesive layer exhibiting good adhesive properties.

[0106] The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes configurations that are substantially identical to the configurations described in the embodiments (for example, configurations with the same function, method and result, or configurations with the same purpose and effect). The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. Furthermore, the present invention includes configurations that produce the same effects or achieve the same purpose as the configurations described in the embodiments. Furthermore, the present invention includes configurations that add known technology to the configurations described in the embodiments.

Claims

1. A kit comprising a first composition and a second composition for preparing a urethane adhesive, The first composition contains a compound (A1) having two or more hydroxyl groups and two or more urea structures, and a compound (A2) having two or more hydroxyl groups. The second composition contains a compound (B1) having two or more isocyanate groups. A kit for preparing urethane adhesive.

2. The urethane adhesive preparation kit according to claim 1, wherein when the content of compound (A1) is MA1 [parts by mass] and the content of compound (A2) is MA2 [parts by mass], MA1 / MA2 = 0.01 to 0.

23.

3. The urethane adhesive preparation kit according to claim 1, wherein the compound (A1) further has an ester structure.

4. The urethane adhesive preparation kit according to claim 1, wherein the compound (A1) is a compound represented by the following general formula (1). HO-R １ -NHGNH-R ２ -NHGNH-R １ -OH ・・・・(1) (In equation (1), there are multiple R １ and R ２ (Each of these independently represents a divalent organic group.)

5. A method for preparing a urethane adhesive, comprising the step of mixing 100 to 250 parts by mass of the first composition with 100 parts by mass of the second composition using a urethane adhesive preparation kit according to any one of claims 1 to 4.

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