Moisture-curing hot melt adhesive

Abstract

The present invention provides a moisture-curing hot melt adhesive having both good coagulation strength and sufficiently long bonding time. The moisture-curing hot melt adhesive is a moisture-curing hot melt adhesive comprising an alkoxysilyl-containing urethane prepolymer (A) represented by the following general formula (a). #imgabs0# In general formula (a), Y represents a residue obtained by removing ‑O‑C(=O)‑NH‑A‑NCO from an isocyanate-terminated urethane prepolymer (a1) which is a reactant of a diisocyanate (i) and a polyol (ii), wherein A represents a residue obtained by removing two isocyanate groups from a divalent diisocyanate, W represents a residue obtained by removing an active hydrogen group from a compound (a2) comprising an alkoxysilyl group and an active hydrogen group, and X represents O, S, or NR 1 , where R 1 It is a hydrogen atom or a linear or branched monovalent hydrocarbon group having 1 to 20 carbon atoms.

Description

Technical Field

[0001] The present invention relates to a moisture-curing hot-melt adhesive. Background Art

[0002] Reactive polyurethane hot-melt adhesives containing isocyanate functional groups (hereinafter sometimes referred to as "PU hot-melt adhesives") are conventionally known. These are prepared from prepolymers that irreversibly cure due to the action of atmospheric moisture or moisture contained in the materials being bonded. For example, the prepolymer described in Patent Document 1 is a reaction product of a compound obtained by reacting a polyisocyanate with a polyester polyol and, as desired, a polyether polyol. Reactive PU hot-melt adhesives such as these are generally used as adhesives for bonding a variety of materials, such as plastics, glass, metal, leather, and wood.

[0003] The setting time of a PU hot-melt adhesive, which does not involve the interaction of its starting components, can be adjusted within a range of seconds to minutes by varying the blending ratio of components that are crystalline or amorphous at room temperature. It is known that the crystalline structure of a PU hot-melt adhesive reduces its melt viscosity, improving its coating properties. It also provides excellent low-temperature elasticity due to its short setting time and low glass transition temperature after application (see, for example, Patent Documents 2 and 3).

[0004] Curing, accompanied by a cross-linking reaction between the reactive PU hot-melt adhesive components, proceeds over several days through the reaction of isocyanate groups with water, forming a thermosetting polyurea. The PU hot-melt adhesive then no longer melts or, for example, exhibits solvent-insoluble properties. As a result, the cured adhesive exhibits excellent heat resistance and resistance to chemicals such as plasticizers, solvents, oils, and fuels.

[0005] However, due to their preparation methods, adhesives such as those mentioned above contain high concentrations of free monomeric polyisocyanates, such as 4,4'-diisocyanatodiphenylmethane (4,4'-MDI), 2,4-diisocyanatotoluene, or 2,6-diisocyanatotoluene (TDI). These monomeric polyisocyanates release their monomeric components into the surrounding atmosphere as vapor at the adhesive coating temperature (approximately 100°C to 180°C), necessitating the installation of designated exhaust systems and other equipment.

[0006] Furthermore, the aforementioned adhesive forms polyurea through reaction with water. When polyurea forms, carbon dioxide is released from the adhesive. Consequently, foaming occurs in the adhesive bonded area. This results in surface expansion of the bonded components and a reduction in bond strength.

[0007] Furthermore, reactive hot-melt adhesives require a balance between stability when heated (no increase in viscosity, or even no curing) and curability at room temperature. However, reactive PU hot-melt adhesives suffer from insufficient stability when heated. Specifically, when reactive PU hot-melt adhesives are heated and melted before application, the isocyanate groups at the ends of the molecular chains react with the urethane and urea bonds within the molecular chain to form allophanate and biuret bonds, creating a three-dimensional crosslinked structure. This can increase the viscosity of the composition or cause it to gel.

[0008] In order to solve this problem, for example, silane-functional reactive hot-melt adhesives based on polyester polyols are known, as disclosed in Patent Documents 4 to 6.

[0009] However, the adhesive composition described in Patent Document 4 is a pressure-sensitive adhesive (tackifier) that retains tack even after curing, and thus a sticky feeling may be a problem depending on the application. Furthermore, the composition described in Patent Document 5 may not have sufficient cohesive strength. The moisture-curable hot-melt adhesive composition described in Patent Document 6 has difficulty achieving both sufficient bonding time and sufficient cohesive strength.

[0010] [Prior art literature]

[0011] [Patent Document]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 4-227714

[0013] [Patent Document 2] Japanese Patent Application Laid-Open No. 2-088686

[0014] [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-205764

[0015] [Patent Document 4] Japanese Patent No. 6027146

[0016] [Patent Document 5] Japanese Patent No. 5738849

[0017] [Patent Document 6] Japanese Patent No. 5254804 Summary of the Invention

[0018] [Problems to be Solved by the Invention]

[0019] That is, compared to the prior art techniques such as those described in the aforementioned patent documents, it is necessary to ensure that the hot melt adhesive has higher coagulation strength and a sufficiently long bonding time. Therefore, an object of the present invention is to provide a moisture-curing hot melt adhesive that can achieve both good coagulation strength and a sufficiently long bonding time.

[0020] [Methods used to solve the problem]

[0021] To achieve the above object, the present invention provides a moisture-curable hot-melt adhesive comprising an alkoxysilyl group-containing urethane prepolymer (A) represented by the following general formula (a).

[0022]

[0023] In the general formula (a), A represents a residue obtained by removing two isocyanate groups from a divalent diisocyanate, Y represents a residue obtained by removing -OC(=O)-NH-A-NCO from an isocyanate-terminated urethane prepolymer (a1) which is a reactant of a diisocyanate (i) and a polyol (ii), W represents a residue obtained by removing an active hydrogen group from a compound (a2) containing an alkoxysilyl group and an active hydrogen group, the polyol (ii) is a polyether polyol (ii-1), the compound (a2) containing an alkoxysilyl group and an active hydrogen group is solid at room temperature, and the methyl methacrylate polymer (a2-1) having an alkoxysilyl group and a hydroxyl group is obtained, and X represents O, S, or NR 1 , where R 1 is a hydrogen atom, or represents a linear or branched monovalent hydrocarbon group having 1 to 20 carbon atoms, which may optionally contain a cyclic part, or represents a group of the general formula (b).

[0024]

[0025] R 2 and R 3 Each independently represents a hydrogen atom, or 5 、-COOR 5 , and -CN, and further, R 4 Represents a hydrogen atom, or from -CH2-COOR 5 、-COOR 5 、-CONHR 5 、-CON(R 5 )2、-CN、-NO2、-PO(OR 5 )2, -SO2R 5 , and -SO2OR 5 The group selected from the group consisting of 5 represents a hydrocarbon group having 1 to 20 carbon atoms, which may optionally contain one or more heteroatoms, and n is a number of 1 or greater.

[0026] [Effects of the Invention]

[0027] According to the moisture-curable hot-melt adhesive of the present invention, a moisture-curable hot-melt adhesive having both good coagulation strength and a sufficiently long bonding time can be provided. DETAILED DESCRIPTION

[0028] [Modes for carrying out the invention]

[0029] <Definition / Meaning of Numerical Values and Terms>

[0030] The definitions and meanings of numerical values and terms used in this specification are as follows.

[0031] The so-called "room temperature" or "normal temperature" is 23°C.

[0032] The term "solid at room temperature" means that the substance in question (e.g., a specified composition) is a crystalline, partially crystalline, and / or glassy amorphous substance, and has a softening point (measured by the ring and ball method) or a melting point higher than 23°C. Here, the melting point is the maximum value of a curve measured during heating by dynamic differential calorimetry (differential scanning calorimetry [DSC]), for example, and is the temperature at which the substance transitions from a solid to a liquid state. Therefore, the term "liquid at room temperature" means having a softening point or melting point of 23°C or lower.

[0033] The so-called "bonding time" is the time from applying the adhesive to the adherend to bonding it to another adherend. The "bonding time" can be measured in accordance with the Japanese Adhesive Industry Standard JAI7-1991.

[0034] The so-called "setting time" is the time it takes for a hot melt adhesive to cool and solidify after being bonded to an adhesive material, thereby exhibiting initial adhesion.

[0035] <Overview of Moisture-Curing Hot Melt Adhesives>

[0036] Hot melt adhesives are required to have sufficiently high coagulation strength after application (in other words, the time required to achieve sufficient bonding strength due to coagulation is practically short). Furthermore, the bonding time, which allows the hot melt adhesive to adhere to another substrate without the hot melt adhesive being able to properly bond to the other substrate, must be sufficiently long. Coagulation strength refers to the strength achieved by the hot melt adhesive curing, where coagulation refers to the process of melting the hot melt adhesive by heating and then cooling it to a solid state. Reactive hot melt adhesives, on the other hand, cure after coagulation through a cross-linking reaction caused by moisture curing, such as silyl groups in the adhesive.

[0037] The inventors of this application have studied various compounds and compositions that constitute hot-melt adhesives and have discovered that by including a crystalline structure while also partially containing regions of amorphous molecules, and by selecting specific blending components, sufficient cohesive strength and a sufficiently long bonding time can be achieved. Furthermore, they discovered that by incorporating reactive groups into prepolymers and other materials that constitute the adhesive, a cross-linking reaction can primarily proceed after the adhesive has cured, significantly enhancing the adhesive's ultimate strength. Specifically, they discovered that by incorporating crystalline compounds into the materials that constitute the hot-melt adhesive, bonding time can be adjusted. For example, by partially containing amorphous regions equivalent to ether bonds, such as those in polyethers, flexibility can be ensured. Furthermore, by incorporating prepolymers and other materials with reactive groups at their terminals, the cross-linking reaction that primarily begins after application of the adhesive can proceed over time, significantly enhancing ultimate strength.

[0038] That is, the moisture-curable hot-melt adhesive of the present invention is a moisture-curable hot-melt adhesive containing an alkoxysilyl group-containing urethane prepolymer (A) (hereinafter referred to as component (A)) represented by the following general formula (a).

[0039]

[0040] In the general formula (a), A represents a residue obtained by removing two isocyanate groups from a divalent diisocyanate, Y represents a residue obtained by removing -OC(=O)-NH-A-NCO from an isocyanate-terminated urethane prepolymer (a1) which is a reactant of a diisocyanate (i) and a polyol (ii) (hereinafter referred to as a Y residue), W represents a residue obtained by removing an active hydrogen group from a compound (a2) containing an alkoxysilyl group and an active hydrogen group, the polyol (ii) is a polyether polyol (ii-1), the compound (a2) containing an alkoxysilyl group and an active hydrogen group has an alkoxysilyl group and a hydroxyl group and is a methyl methacrylate-based polymer (a2-1) that is solid at room temperature, and X represents O, S, or NR 1 , where R 1 is a hydrogen atom, or represents a linear or branched monovalent hydrocarbon group having 1 to 20 carbon atoms, which may optionally contain a cyclic part, or represents a group of the general formula (b).

[0041]

[0042] R 2 and R 3 Each independently represents a hydrogen atom, or 5 、-COOR 5 , and -CN, and further, R 4 Represents a hydrogen atom, or from -CH2-COOR 5 、-COOR5 、-CONHR 5 、-CON(R 5 )2、-CN、-NO2、-PO(OR 5 )2, -SO2R 5 , and -SO2OR 5 The group selected from the group consisting of R 5 represents a hydrocarbon group having 1 to 20 carbon atoms, which may optionally contain one or more heteroatoms, and n is a number of 1 or greater.

[0043] The moisture-curable hot-melt adhesive of the present invention comprises an alkoxysilyl-containing urethane prepolymer (A) of general formula (a) (hereinafter referred to as component (A)). Component (A) is generally obtained by reacting an isocyanate-terminated urethane prepolymer (a1) of formula (I) (hereinafter referred to as component (a1)) with a compound (a2) containing an alkoxysilyl group and an active hydrogen group of formula (II) (hereinafter referred to as component (a2)).

[0044]

[0045] In formula (I), A, Y, and n are the same as described above.

[0046] HX-W (II)

[0047] In formula (II), X and W are the same as described above.

[0048] In addition, the preparation method of component (a1) is not particularly limited. For example, component (a1) can also be prepared in the form of a reaction product of diisocyanate (i) (hereinafter referred to as component (i)) and polyol (ii) (hereinafter referred to as component (ii)). Furthermore, component (ii) may also contain polyether polyol (ii-1) (hereinafter referred to as component (ii-1)). Here, component (ii) may further contain polyester polyol (ii-2) (hereinafter referred to as component (ii-2)) and / or polycarbonate polyol (ii-3) (hereinafter referred to as component (ii-3)) in addition to component (ii-1) or in place of a part of component (ii-1). In addition, component (ii-2) may also be a crystalline aliphatic polyester polyol (ii-2-1) (hereinafter referred to as component (ii-2-1)).

[0049] Furthermore, component (a2) is a methyl methacrylate polymer (a2-1) (hereinafter referred to as component (a2-1)) that is solid at room temperature and has an alkoxysilyl group and a hydroxyl group at the terminal. Component (a2) may further contain an alkoxysilane (a2-2) (hereinafter referred to as component (a2-2)) having an active hydrogen group in addition to component (a2-1) or as a substitute for a portion of component (a2-1).

[0050] (Other Preparation Methods of Component (A))

[0051] Component (A) can also be obtained by reacting a hydroxyl-terminated polymer (a1") represented by formula (III) (hereinafter referred to as component (a1")) with a compound (a2") represented by formula (IV) containing an alkoxysilyl group and an isocyanate group (hereinafter referred to as component (a2")). Component (a2") is also obtained by reacting a compound (a2) containing an alkoxysilyl group and an active hydrogen group with a diisocyanate (formula: OCN-A-NCO).

[0052]

[0053] Furthermore, Y" is a residue obtained by removing a hydroxyl group from the polyol (ii) (hereinafter referred to as the Y" residue), which has the same structure as the residue (Y residue) obtained by removing -OC(=O)-NH-A-NCO from the isocyanate-terminated urethane prepolymer (a1), wherein the isocyanate-terminated urethane prepolymer (a1) is the reaction product of the above-mentioned diisocyanate (i) and the polyol (ii).

[0054]

[0055] Here, A, X, and W are the same as above.

[0056] Furthermore, the moisture-curable hot-melt adhesive of the present invention may further contain, in addition to the above-mentioned components: a silane-based tackifier (B) (hereinafter referred to as component (B)), a modified resin (C) (hereinafter referred to as component (C)), at least one catalyst (crosslinking catalyst) (D) selected from the group consisting of an amine compound, a divalent tin compound, and a fluorinated polymer (hereinafter referred to as component (D)), and / or a silylated polymer (E) (hereinafter referred to as component (E)).

[0057] Furthermore, the hot melt adhesive of the present invention can also be configured as a photocurable adhesive.

[0058] <Details of moisture-curing hot-melt adhesive>

[0059] The moisture-curable hot-melt adhesive of the present invention comprises an alkoxysilyl group-containing urethane prepolymer (A) represented by the general formula (a), and the method for preparing the component (A) is not particularly limited.

[0060] As an example, a moisture-curable hot melt adhesive can be prepared by containing component (A), wherein component (A) is prepared by reacting component (i) with component (ii) to prepare component (a1), and then reacting the resulting component (a1) with component (a2). Furthermore, the moisture-curable hot melt adhesive of the present invention can be prepared by adding component (B), component (C), component (D), component (E), and / or other additives to component (A). Furthermore, component (A) can be prepared by reacting component (a2) with component (i) or component (ii), and further reacting with component (ii) or component (i), or by reacting components (i), (ii), and (a2) simultaneously.

[0061] The hot melt adhesive of the present invention is solid at room temperature and is applied to the adherend in a heated, molten state. The components encompassed are described in detail below. Furthermore, in the following description, the moisture-curing hot melt adhesive of the present invention may sometimes be referred to as a "reactive hot melt adhesive" or a "one-component moisture-curing reactive hot melt adhesive."

[0062] <(A) Alkoxysilyl-containing urethane prepolymer>

[0063] The alkoxysilyl-containing urethane prepolymer (A) of the present invention is a polymer having an alkoxysilyl group represented by the general formula (a) and containing a urethane bond. The alkoxysilyl-containing urethane prepolymer (A) is a polymer having a polyether skeleton (a skeleton formed by removing hydroxyl groups from a polyether polyol) as an essential component, and is a polymer formed by linking a polymer containing a polyether skeleton with a skeleton of an acrylic polymer containing an alkoxysilyl group (a skeleton formed by removing hydroxyl groups from a methyl methacrylate polymer having alkoxysilyl groups and hydroxyl groups) via a urethane bond. This urethane bond is formed by a linking group of the following general formula (V) produced by the reaction of the terminal hydroxyl groups of the polyether polyol and the acrylic polymer containing an alkoxysilyl group with a linking agent (diisocyanate compound). By linking the two polymers, a polymer having toughness and flexibility is formed.

[0064] -OC(=O)NH-A-NHC(=O)O- (V)

[0065] Furthermore, A is the same as above.

[0066] From the viewpoint of increasing the coagulation strength of the hot-melt adhesive of the present invention, the component (A) is preferably solid at room temperature.

[0067] <(a1) Isocyanate-terminated urethane prepolymer>

[0068] The isocyanate-terminated urethane prepolymer (a1) of the present invention can be prepared by a conventionally known method, for example, by reacting a predetermined diisocyanate component (component (i)) with a predetermined polyol component (component (ii)).

[0069] For example, the isocyanate-terminated urethane prepolymer (a1) of the present invention is obtained by reacting a diisocyanate with a polyether polyol so that the molar ratio of the isocyanate groups of the diisocyanate to the hydroxyl groups of the polyether polyol (hereinafter referred to as the isocyanate / hydroxyl molar ratio) exceeds 1, that is, the isocyanate groups are in excess relative to the hydroxyl groups. Here, the isocyanate / hydroxyl molar ratio is preferably 1.5 or more, more preferably 1.8 or more, and even more preferably 1.9 or more, and is preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.1 or less. When the isocyanate / hydroxyl molar ratio is within this range, good coating properties are obtained.

[0070] Furthermore, the isocyanate-terminated urethane prepolymer (a1) can also be obtained by using a diisocyanate having an isocyanate group (e.g., 1,6-diisocyanatohexane (HDI), 2,4-diisocyanatotoluene (TDI), 2,6-diisocyanatotoluene (TDI), 2,4'-diisocyanatodiphenylmethane (MDI), 4,4'-diisocyanatodiphenylmethane (MDI)) having an insufficient molar ratio relative to the hydroxyl groups of the polyether polyol, modifying the polyether polyol or a portion of these, and then reacting the excess diisocyanate with a polyol having a urethane group after the reaction is completed.

[0071] The polyether polyol and diisocyanate may be reacted in the presence of up to 5 wt% of a trimer of an aliphatic diisocyanate (e.g., hexamethylene diisocyanate), or the trimer may be added after the prepolymerization reaction.

[0072] [Polyisocyanate]

[0073] The polyisocyanate of the present invention is not particularly limited, but examples thereof include diisocyanates.

[0074] ((i) Diisocyanate)

[0075] The (i) diisocyanate is not particularly limited, but examples thereof include compounds represented by the following formula (c).

[0076] OCN-A-NCO formula (c)

[0077] In formula (c), A is a divalent residue obtained by removing two isocyanate groups from a diisocyanate, and represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon group having 3 to 20 carbon atoms including an alicyclic structure, or a hydrocarbon group having 6 to 20 carbon atoms including an aromatic ring.

[0078] Specific examples include aromatic diisocyanates such as phenylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate; and aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate. Among these, diphenylmethane diisocyanate, which has a low vapor pressure when heated, is preferably used in a hot-melt adhesive for use in a melt-applied process.

[0079] [(ii) Polyols]

[0080] Examples of the polyol that can be used in the present invention include polyester polyols, polyether polyols, acrylic polyols, polycarbonate polyols, polyolefin polyols, castor oil polyols, and mixtures or copolymers thereof.

[0081] The polyol component (ii) contains (ii-1) a polyether polyol as an essential component of the present invention. Component (ii) may further contain a polyester polyol (ii-2) and / or a polycarbonate polyol (ii-3). Component (ii-2) may also be a crystalline aliphatic polyester polyol (ii-2-1).

[0082] In addition, when component (ii) further contains polyester polyol (ii-2) and / or polycarbonate polyol (ii-3), the isocyanate-terminated urethane prepolymer (a1) of the present invention is obtained by making the castor oil diisocyanate and the polyol a molar ratio of the isocyanate groups of the diisocyanate to the hydroxyl groups of the polyol (hereinafter referred to as the isocyanate group / hydroxyl group molar ratio) exceeding 1. That is, the isocyanate groups react in excess relative to the hydroxyl groups, and the component (ii) and (ii-2) and / or (ii-3) are linked by the diisocyanate. In this case, from the perspective of obtaining good coating properties, the isocyanate group / hydroxyl group molar ratio is preferably 1.2 or more, more preferably 1.3 or more, and even more preferably 1.4 or more. Furthermore, from the perspective of obtaining good curing properties, it is preferably 1.9 or less, more preferably 1.7 or less, and even more preferably 1.6 or less.

[0083] ((ii-1) Polyether polyol)

[0084] Examples of polyether polyols include polypropylene glycol (PPG), polyethylene glycol (PEG), and polytetramethylene glycol (PTMG). These polyols are not limited, but the number average molecular weight is preferably 500 or greater, more preferably 1,000 or greater, and even more preferably 2,000 or greater, and preferably 30,000 or less, more preferably 20,000 or less, and even more preferably 15,000 or less. Furthermore, the polyether polyol is preferably a diol.

[0085] Furthermore, compounds obtained by copolymerizing two or more polyether polyols can be used as polyether polyols, and examples thereof include polyoxyethylene-polyoxypropylene block copolymer diols. These diols are preferred because they have primary hydroxyl terminal groups and good reactivity with isocyanate groups. Polyoxyethylene-polyoxypropylene block copolymer diols preferably have an ethylene oxide content of 5% by weight or more, preferably 90% by weight or less, more preferably 40% by weight or less, and even more preferably 20% by weight or less.

[0086] ((ii-2) Polyester polyol)

[0087] The polyester polyol (hereinafter sometimes simply referred to as "polyester polyol") used as the (ii) polyol component means a polyester having more than one OH group (preferably two terminal OH groups).

[0088] The moisture-curable hot-melt adhesive of the present invention contains, as the polyol component (ii), at least one polyester polyol having at least two functional groups and being solid (preferably at least partially crystalline) at room temperature.

[0089] Furthermore, the moisture-curing hot-melt adhesive may also contain, among the (ii) polyol component: one or more polyester polyols having at least two functionalities and being at least partially crystalline; one or more aromatic polyester polyols or alicyclic polyester polyols having at least two functionalities; one or more polyester polyols having at least two functionalities and being liquid at room temperature; and / or one or more polyether polyols having at least two functionalities.

[0090] Here, the meaning of "at least partially crystalline" is explained. A "at least partially crystalline" polyester polyol means that the polyester polyol is not completely crystalline but rather partially or additionally contains a certain amorphous portion. As described above, polyester polyols have a crystalline melting point (Tm) and a glass transition temperature (hereinafter sometimes referred to as "Tg"). The melting point represents the temperature at which the crystalline portion melts. The melting point can be determined, for example, by differential thermal analysis using DSC (DSC) as the primary endothermic peak (crystalline melting peak). According to DSC measurements (with a heating and cooling rate of 10 K / min in the second heating step), the melting point of at least partially crystalline polyester polyols is approximately 35°C to 120°C. The glass transition temperature of at least partially crystalline polyester polyols is generally, for example, well below room temperature. Suitable partially crystalline polyester polyols (hereinafter referred to as "crystalline aliphatic polyester polyols") are well known to those skilled in the art. Furthermore, the polyester polyol may also be a polyester polyol linked with a diisocyanate.

[0091] ((ii-2-1) Crystalline aliphatic polyester polyol)

[0092] As the crystalline aliphatic polyester polyol (ii-2-1), for example, a compound obtained by reacting a compound having two or more hydroxyl groups with a polybasic acid can be used. Alternatively, a bifunctional starter molecule such as a polycaprolactone derivative based on 1,6-hexanediol can be used.

[0093] Specifically, examples of compounds having two or more hydroxyl groups (preferably 2 to 3, more preferably 2) include linear aliphatic diols having 2 to 16 carbon atoms, such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol; and aliphatic triols such as trimethylolethane, trimethylolpropane, pentaerythritol, and glycerol. Among these, linear aliphatic diols preferably have 4 to 14 carbon atoms, more preferably 6 to 12 carbon atoms, from the perspective of improving crystallinity. These compounds may be used alone or in combination of two or more.

[0094] Examples of polybasic acids that can be used include linear aliphatic dicarboxylic acids having 2 to 16 carbon atoms, such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, and 1,12-dodecanedicarboxylic acid. Among these, linear aliphatic dicarboxylic acids preferably have 6 to 14 carbon atoms, and more preferably 8 to 12 carbon atoms, from the perspective of improving crystallinity. These polybasic acids may be used alone or in combination of two or more.

[0095] Furthermore, as the crystalline aliphatic polyester polyol, specifically, a long-chain aliphatic polyester polyol represented by the following general formula (VI) is preferred.

[0096]

[0097] In the general formula (VI), R 6 and R 7 are each independently a straight-chain alkylene group having an even number of carbon atoms, and R 6 and R 7 The total number of carbon atoms is 12 or more. In addition, n represents 3 to 40.

[0098] Here, as R in the general formula (VI), 6 , can be cited as a straight chain alkylene group having an even number of carbon atoms, and can be in R 6 With R 7 The total number of carbon atoms is appropriately selected from a range of 12 or more. 7 , preferably an even-numbered linear alkylene group having 4 or more carbon atoms.

[0099] Furthermore, R in the general formula (VI) 7 , can be listed with R 6 Independent and carbon number is an even number of straight chain alkylene, and can be in R 6 With R 7 The total number of carbon atoms is appropriately selected from a range of 12 or more. 7 , preferably a straight-chain alkylene group having an even number of 10 or more carbon atoms.

[0100] By using R 6 and R 7 The long-chain aliphatic polyester polyols each having a linear alkylene group with a carbon number within the above range can improve the crystallinity of the resulting urethane prepolymer and can provide a moisture-curable hot-melt adhesive having excellent initial adhesion strength and normal adhesion strength.

[0101] Furthermore, n in the general formula (VI) is 3 to 40, preferably 9 to 25, and more preferably 9 to 15. By using a long-chain aliphatic polyester polyol having n within this range, a moisture-curable hot-melt adhesive having an appropriate melt viscosity and excellent coating workability can be obtained.

[0102] Specifically, examples of the crystalline aliphatic polyester polyol include polyhexamethylene adipate, polyhexamethylene sebacate, polyhexamethylene dodecanoate, and polydodecane dioleate, and polyhexamethylene sebacate, polyhexamethylene dodecanoate, and polydodecane dioleate are preferred.

[0103] Here, from the perspective of shortening the time required to achieve sufficient initial strength by crystallizing the molten component after using a composition containing a crystalline aliphatic polyester polyol, the crystallization temperature of the crystalline aliphatic polyester polyol is preferably 30°C or less lower than the melting point of the crystalline aliphatic polyester polyol. This allows the moisture-curing hot-melt adhesive of the present invention to bond adherends together, providing sufficient initial strength. This eliminates the need to secure one adherend to the other until any misalignment between the adherends is eliminated, or allows only a short period of securement to suffice. This is particularly convenient for vertical bonding, such as bonding windshields and windows in automobiles or transportation equipment. Furthermore, because it has high resistance to rebound (forces that attempt to peel) of the substrate and can be fixed in a short time, it can be used to form decorative fixing components by laminating substrates such as plywood, MDF (medium density fiberboard), and particle board to decorative sheets or films, decorative papers, thin plates, metal foils, etc. with decorative colors or patterns applied to the surface.

[0104] The crystalline aliphatic polyester polyol preferably has a number average molecular weight of 1,500 or greater, more preferably 2,500 or greater, and even more preferably 3,500 or greater. It is preferably 10,000 or less, more preferably 7,000 or less, and even more preferably 6,000 or less. When polycaprolactone polyol is used as the crystalline aliphatic polyester polyol, the number average molecular weight is preferably in the range of 20,000 or more and 200,000 or less. The melting point of the crystalline aliphatic polyester polyol is preferably 35°C or greater, more preferably 45°C or greater, even more preferably 55°C or greater, and preferably 120°C or less, more preferably 100°C or less, and even more preferably 80°C or less.

[0105] (Aromatic polyester polyol)

[0106] As the aromatic polyester polyol, for example, a reaction product of an aromatic polycarboxylic acid and a low-molecular-weight aliphatic polyol can be used.

[0107] As the aromatic polycarboxylic acid, phthalic acid (for example, phthalic acid, phthalic anhydride), isophthalic acid, and terephthalic acid can be used. These aromatic polycarboxylic acids can be used alone or in combination of two or more.

[0108] The aromatic polycarboxylic acid may be used in combination with other polybasic acids as needed. In this case, the content of the aromatic polycarboxylic acid is preferably 60% by mass or more, more preferably 80% by mass or more, based on the total amount of the polybasic acids.

[0109] Examples of other polybasic acids include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, and 1,12-dodecanedicarboxylic acid. These polybasic acids may be used alone or in combination of two or more. Among these polybasic acids, adipic acid and sebacic acid are preferred.

[0110] Examples of the low-molecular-weight aliphatic polyol include linear aliphatic diols having 2 to 16 carbon atoms. Among the linear aliphatic diols, ethylene glycol, 1,4-butanediol, and 1,6-hexanediol are preferred, and ethylene glycol and 1,6-hexanediol are more preferred.

[0111] Examples of low-molecular-weight aliphatic polyols include branched-chain aliphatic diols such as neopentyl glycol, 1,3-butanediol, 2,2-diethyl-1,3-propanediol, 2,2-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-methyl-1,8-octanediol, and 2,4-diethyl-1,5-pentanediol. Among the branched-chain aliphatic diols, neopentyl glycol and 3-methyl-1,5-pentanediol are preferred, and neopentyl glycol is more preferred.

[0112] Examples of low-molecular-weight aliphatic polyols include those having ether bonds, such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. Among these, diethylene glycol is preferred. Furthermore, aromatic polyols obtained by ring-opening addition reaction of ethylene oxide, propylene oxide, γ-butyrolactone, ε-caprolactone, and the like with bisphenol A, bisphenol F, and the like can also be used as aliphatic polyols. Among these, aromatic polyols obtained by ring-opening addition reaction of ethylene oxide with bisphenol A are preferred.

[0113] These low molecular weight aliphatic polyols may be used alone or in combination of two or more. Among these, neopentyl glycol and diethylene glycol are preferably used from the viewpoint of improving amorphous properties.

[0114] Here, the number average molecular weight of the aromatic polyester polyol is preferably 900 or more, more preferably 1,000 or more, and is preferably 5,000 or less, more preferably 3,000 or less.

[0115] Furthermore, examples of the aromatic polyester polyol include: an aromatic polyester polyol having a number average molecular weight of 2,000 to 5,000 and a glass transition temperature of 30°C or higher (hereinafter referred to as "aromatic polyester polyol that is solid at room temperature"); and an aromatic polyester polyol having a number average molecular weight of 400 to 3,500 and a glass transition temperature of 20°C or lower (hereinafter referred to as "aromatic polyester polyol that is liquid at room temperature").

[0116] (Aromatic polyester polyol solid at room temperature)

[0117] Aromatic polyester polyols that are solid at room temperature can be produced, for example, by a method of condensing an aromatic polycarboxylic acid with a low-molecular-weight aliphatic polyol.

[0118] The room-temperature solid aromatic polyester polyol is preferably one obtained by appropriately combining ethylene glycol and neopentyl glycol as low-molecular-weight aliphatic polyols with isophthalic acid and terephthalic acid as aromatic polycarboxylic acids so that the glass transition temperature is 30° C. or higher, and then condensing them by a known method.

[0119] Aromatic polyester polyols that are solid at room temperature are compounds having a glass transition temperature of 30°C or higher, more preferably within the range of 30°C to 70°C. Using aromatic polyester polyols that are solid at room temperature and have a glass transition temperature within this range provides a moisture-curable hot-melt adhesive exhibiting excellent bond strength. This can further enhance adhesion to aromatic resins such as polyethylene terephthalate, while also imparting toughness and improving both set strength and ultimate strength.

[0120] (Aromatic polyester polyol that is liquid at room temperature)

[0121] As the aromatic polyester polyol that is liquid at room temperature, for example, one obtained by reacting a low-molecular-weight aliphatic polyol or a branched aliphatic diol having an ether bond with an aromatic polycarboxylic acid can be used.

[0122] Aromatic polyester polyols that are liquid at room temperature have a glass transition temperature of 20°C or lower. Furthermore, aromatic polyester polyols that are liquid at room temperature preferably have a glass transition temperature within the range of -30°C to 20°C. Within this range, a moisture-curable hot-melt adhesive exhibiting superior normal-state adhesive strength can be obtained.

[0123] (Alicyclic polyester polyol)

[0124] Alicyclic polyester polyols can be produced, for example, by reacting an alicyclic polyol with an aliphatic polycarboxylic acid (or its acid derivative), or by reacting an aliphatic polyol with an alicyclic polycarboxylic acid (or its acid derivative) by a known reaction method.

[0125] Examples of alicyclic polyols include cyclopentanediol, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, and adducts obtained by adding alkylene oxides such as ethylene oxide (EO) and propylene oxide (PO) to these polyols. These may be used alone or in combination of two or more.

[0126] Examples of the aliphatic polyol include linear aliphatic diols having 2 to 16 carbon atoms, polyalkylene oxide oligomers, branched aliphatic diols, and aliphatic triols. Among these, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and neopentyl glycol are preferred, and neopentyl glycol is more preferred.

[0127] Examples of the alicyclic polycarboxylic acid include cyclohexanedicarboxylic acid and cyclopentanedicarboxylic acid. Among these, cyclohexanedicarboxylic acid (CHDA) is preferred.

[0128] Examples of aliphatic polycarboxylic acids include linear aliphatic dicarboxylic acids having 2 to 16 carbon atoms. Among these, adipic acid, sebacic acid, decanedioic acid, and dodecanedioic acid are preferred, with sebacic acid and dodecanedioic acid being more preferred. These may be used alone or in combination of two or more.

[0129] Furthermore, as the alicyclic polycarboxylic acid and the aliphatic polycarboxylic acid, corresponding acid derivatives such as lower alkyl ester derivatives such as methyl ester, acid anhydrides, and acid halides can also be used.

[0130] The number average molecular weight (Mn) of the alicyclic polyester polyol is preferably 500 or greater, more preferably 700 or greater, and preferably 5,000 or less, more preferably 3,000 or less, and even more preferably 2,000 or less. When the Mn of the alicyclic polyester polyol is within this range, the moisture-curable polyurethane hot-melt adhesive has an appropriate melt viscosity, exhibits excellent coating workability (viscosity suitability) and adhesive strength, and prevents peeling of the surface member (such as a sheet, film, metal foil, or paper) in complex shaped areas of the substrate after lamination.

[0131] (Aliphatic polyester polyol that is liquid at room temperature)

[0132] Examples of the aliphatic polyester polyol that is liquid at room temperature include an aliphatic polyester polyol that has a number average molecular weight of 4,000 to 7,000 and has a branched aliphatic group and is liquid at room temperature.

[0133] To ensure that the resulting adhesive maintains both good wettability and high initial bond strength at low temperatures, aliphatic polyester polyols that are liquid at room temperature must have a number average molecular weight within the range of 4,000 to 7,000. When the number average molecular weight of aliphatic polyester polyols that are liquid at room temperature is less than 4,000, the resulting adhesive may exhibit reduced wettability to the substrate at low temperatures and a significantly reduced normal bond strength. On the other hand, when the number average molecular weight exceeds 7,000, the crosslink density of the resulting cured adhesive increases, resulting in a decrease in hot water-resistant bond strength.

[0134] Furthermore, from the viewpoint of improving the normal-state adhesive strength to substrates with poor adhesion, aliphatic polyester polyols that are liquid at room temperature must have branched aliphatic groups.

[0135] Examples of the branched aliphatic group include branched aliphatic diol groups such as 2,2-dimethyl-1,3-propylene, 2-methyl-1,3-propylene, 1,2-diethyl-1,3-propylene, 2,3-diethyl-1,3-propylene, 3-methyl-1,5-pentylene, 2-ethyl-2-butyl-propylene, 2-methyl-1,8-octylene, and 2,4-diethyl-1,5-pentylene. Among these, 2,2-dimethyl-1,3-propylene and 3-methyl-1,5-pentylene are preferred, and 2,2-dimethyl-1,3-propylene is more preferred.

[0136] Aliphatic polyester polyols that are liquid at room temperature can be produced by methods such as condensation reaction of branched aliphatic diols and polycarboxylic acids, or ring-opening polymerization of caprolactone, γ-butyrolactone, etc. using a branched aliphatic diol as an initiator. Of these, aliphatic polyester polyols obtained by reacting neopentyl glycol or 3-methyl-1,5-pentanediol (of these two, neopentyl glycol is more preferred) with a linear aliphatic diol having 2 to 12 carbon atoms and a linear aliphatic dicarboxylic acid having 4 to 10 carbon atoms are more preferred because they can produce moisture-curable polyurethane hot-melt adhesives with excellent wettability in low-temperature environments.

[0137] When producing an aliphatic polyester polyol that is liquid at room temperature, low-molecular-weight aliphatic polyols and aliphatic polycarboxylic acids other than the compounds exemplified above may be used in combination, if necessary.

[0138] As other low-molecular-weight aliphatic polyols, other aliphatic polyols can be used. Among these, linear aliphatic diols having 2 to 12 carbon atoms are preferably used.

[0139] As the aliphatic polycarboxylic acid, for example, adipic acid, sebacic acid, azelaic acid, decamethylene dicarboxylic acid, etc. can be used in combination. Among these, it is preferable to use a linear aliphatic dicarboxylic acid having 4 to 10 carbon atoms.

[0140] ((ii-3) Polycarbonate polyol)

[0141] In the present invention, the polyol component (ii) may contain a polycarbonate polyol. By using a polycarbonate polyol, the hydrolysis resistance and moisture-resistant adhesiveness of the moisture-curable hot-melt adhesive of the present invention can be improved.

[0142] As the polycarbonate polyol, for example, a compound obtained by reacting a carbonate and / or phosgene with a diol can be used.

[0143] As the carbonate ester, for example, dimethyl carbonate, diphenyl carbonate, etc. These compounds may be used alone or in combination of two or more.

[0144] Examples of diols include linear aliphatic diols such as 1,5-pentanediol, 1,6-hexanediol, and 1,9-nonanediol; branched aliphatic diols such as neopentyl glycol, 3-methyl-1,5-pentanediol, and 2-methyl-1,8-octanediol; and 1,4-cyclohexanedimethanol and bisphenol A. These compounds may be used alone or in combination of two or more.

[0145] ((ii-3-1) Crystalline aliphatic polycarbonate polyol)

[0146] Here, a polycarbonate polyol having only one type of linear aliphatic diol is solid at room temperature and has crystallinity. In the present invention, it is preferred to use a polycarbonate polyol having only 1,6-hexanediol.

[0147] (Polycarbonate polyol that is liquid at room temperature)

[0148] Examples of polycarbonate polyols obtained by copolymerizing at least two diols include copolymerized polycarbonate diols composed of 3-methyl-1,5-pentanediol and 1,6-hexanediol as diol components, copolymerized polycarbonate diols composed of 1,5-pentanediol and 1,6-hexanediol, and copolymerized polycarbonate diols composed of 2-methyl-1,8-octanediol and 1,9-nonanediol. The use of these polycarbonate polyols, which are liquid at room temperature, can improve the flexibility of the cured film of the moisture-curable hot-melt adhesive of the present invention.

[0149] From the viewpoint of further improving the adhesiveness of the moisture-curable hot-melt adhesive of the present invention, the number average molecular weight of the polycarbonate polyol is preferably 500 or more, more preferably 1,000 or more, and preferably 5,000 or less, more preferably 4,000 or less.

[0150] From the viewpoint of further improving drop impact resistance and adhesiveness, the glass transition temperature (Tg) of the polycarbonate polyol is preferably in the range of -30 to 20°C.

[0151] (Glass transition temperature: Tg)

[0152] The polyester polyols and polycarbonate polyols are liquid (glass transition temperature Tg < 20°C) or solid at room temperature. However, the polyester polyols and polycarbonate polyols that are solid at room temperature are amorphous (Tg > 20°C) or at least partially crystalline.

[0153] <(a2) Compound containing an alkoxysilyl group and an active hydrogen group>

[0154] The compound (a2) containing an alkoxysilyl group and an active hydrogen group is a compound that reacts with the isocyanate-terminated urethane prepolymer (a1). It is a compound having an alkoxysilyl group and an active hydrogen group, preferably having an active hydrogen group and an alkoxysilyl group at the terminal, and preferably having at least one active hydrogen group at the terminal.

[0155] In addition, the compound (a2) containing an alkoxysilyl group and an active hydrogen group may also have an active hydrogen group randomly in a portion other than the terminal and at the terminal. From the viewpoint of improving the final strength and heat resistance due to the cross-linking reaction of the alkoxysilyl group, the compound (a2) containing an alkoxysilyl group and an active hydrogen group preferably has an average of 0.3 or more hydroxyl groups, more preferably an average of 0.5 or more, and further preferably an average of 0.8 or more. From the viewpoint of lowering the molecular weight of the urethane prepolymer (A) containing an alkoxysilyl group and lowering the viscosity of the polymer, it is preferred that the average number of hydroxyl groups be 1.7 or less, more preferably an average of 1.4 or less, and further preferably an average of 1.2 or less. It is particularly preferred to have a single hydroxyl group at the terminal. In addition, the boiling point of the compound having an active hydrogen group is preferably 100°C or more, more preferably 150°C or more, and further preferably 200°C or more.

[0156] ((a2-1) Methyl methacrylate polymer that is solid at room temperature and has an alkoxysilyl group and a hydroxyl group at the terminal)

[0157] The moisture-curable hot-melt adhesive of the present invention contains, as component (a2), a methyl methacrylate polymer (a2-1) that is solid at room temperature and has an alkoxysilyl group and a hydroxyl group at its terminal end. Component (a2-1) preferably has an alkoxysilyl group, but may also be, for example, an alkoxysilyl-containing methyl methacrylate polymer having a hydroxyl group. The alkoxysilyl-containing methyl methacrylate polymer having a hydroxyl group can be synthesized, for example, by introducing a hydroxyl group into an alkoxysilyl-containing (meth)acrylate polymer described below.

[0158] It is preferred to introduce one hydroxyl group into the alkoxysilyl-containing methyl methacrylate polymer. Having only one hydroxyl group in the alkoxysilyl-containing methyl methacrylate polymer can suppress gelation. Various well-known methods can be used to introduce hydroxyl groups into the alkoxysilyl-containing methyl methacrylate polymer. Examples of methods for introducing hydroxyl groups include the following. Furthermore, hydroxyl groups can be introduced at locations other than the terminals, and a separate monomer having a hydroxyl group can be added.

[0159] (1) Copolymerizing an unsaturated compound having a hydroxyl group.

[0160] (2) Polymerization is carried out using an initiator or chain transfer agent having a hydroxyl group.

[0161] (3) Reaction using a thiol compound having a hydroxyl group, or polymerization using a thiol compound having a hydroxyl group and a metallocene compound.

[0162] Furthermore, the method of (3) can utilize the method described in Japanese Patent No. 5222467.

[0163] From the viewpoint of being able to introduce one hydroxyl group, a method of introducing a hydroxyl group by polymerization using a thiol compound having a hydroxyl group and a metallocene compound is preferred. Examples of the thiol compound having a hydroxyl group include 2-mercaptoethanol.

[0164] The number (average value) of hydroxyl groups in component (a2-1) is preferably 0.5 or less, more preferably 0.3 or less, and even more preferably 0.1 or less per molecule of the polymer of component (a2-1). Furthermore, the number average molecular weight of component (a2-1) is preferably 1,000 or more, more preferably 2,000 or more, even more preferably 3,000 or more, and preferably 50,000 or less, more preferably 30,000 or less, and even more preferably 15,000 or less.

[0165] (Copolymerization of unsaturated compounds having hydroxyl groups)

[0166] Furthermore, as the unsaturated compound having a hydroxyl group, an alkyl (meth)acrylate having a hydroxyl group is preferred. Examples of such compounds include monohydroxy acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl acrylate; and polyhydroxy acrylates such as glycerol mono(meth)acrylate. Among these, monohydroxy acrylic acid is preferred. Furthermore, the blending ratio of the unsaturated compound having a hydroxyl group is preferably such that the average number of hydroxyl groups of the unsaturated compound having a hydroxyl group is 0.5 to 3 per hydroxyl group per polymer molecule of component (a2-1), and more preferably such that the average number of hydroxyl groups of the unsaturated compound having a hydroxyl group is 1.1 to 2.

[0167] ((a2-2) Alkoxysilane having an active hydrogen group)

[0168] The moisture-curable hot melt adhesive of the present invention may further contain a residue obtained by removing an active hydrogen group from an alkoxysilane having an amino group, a hydroxy group, or a mercapto group. Examples of the active hydrogen group include an amino group, a hydroxy group, and a mercapto group. Examples of the alkoxysilane (a2-2) having an active hydrogen group include compounds represented by the following general formula (VII).

[0169]

[0170] In the general formula (VII), R 8 represents a linear or branched monovalent hydrocarbon radical of 1 to 12 carbon atoms, which optionally has one or more C—C multiple bonds and / or optionally also has alicyclic and / or aromatic moieties. In particular, R 8 represents a methyl group, an ethyl group, or an isopropyl group. 9 represents an acyl residue having 1 to 12 carbon atoms or a linear or branched monovalent hydrocarbon group having 1 to 12 carbon atoms, which may optionally have one or more carbon-carbon multiple bonds and / or may also optionally have alicyclic and / or aromatic moieties. 9 Preferred are acyl or alkyl groups having 1 to 5 carbon atoms, in particular methyl, ethyl or isopropyl. 10 R represents a divalent hydrocarbon radical having 1 to 12 carbon atoms, which may be linear or branched, and which may optionally contain cyclic and / or aromatic moieties and may optionally contain one or more heteroatoms. 10 It is preferably an alkylene residue having 1 to 3 C atoms, particularly 3 C atoms. In the general formula (VII), a represents 0, 1, or 2, particularly 0 or 1. The group X is the same as described above.

[0171] Examples of the compound represented by the general formula (VII) (component (a2-2)) include mercaptosilanes such as γ-mercaptopropyltrimethoxysilane, hydroxyl-containing silanes such as 2-ethoxy-4(5)-(2-triethoxysilylethyl)cyclohexane-1-ol, and aminosilanes. Examples of aminosilanes include primary aminosilanes (e.g., 3-aminopropyltrimethoxysilane), secondary aminosilanes (e.g., N-butyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane), Michael-type adducts of primary aminosilanes (e.g., dimethyl and diethyl N-(3-trimethoxysilylpropyl)aminosuccinate), and analogs of the above aminosilanes having an ethoxy group or an isopropyloxy group in place of the methoxy group bonded to silicon. Particularly suitable aminosilanes include secondary aminosilanes, particularly those represented by the following general formula (VIII): 5 Aminosilanes other than H are preferably Michael adducts, and diethyl N-(3-trimethoxysilylpropyl)aminosuccinate is particularly preferred.

[0172]

[0173] In the general formula (VIII), R 8 、R 9 、R 10 、R 5 , and a are the same as above.

[0174] (Block polymer structure)

[0175] Furthermore, the alkoxysilyl-containing urethane prepolymer (A) of the present invention has a "(hard segment)-(soft segment)-(hard segment)" block polymer structure composed of a "hard segment" of a methyl methacrylate copolymer that is solid at room temperature and a "soft segment" of a polyether. This structure imparts toughness to moisture-curable hot-melt adhesives and improves bonding strength. Furthermore, by incorporating a crystalline polyester into the "soft segment" of the polyether, sufficient bonding time and improved bonding strength can be achieved.

[0176] Furthermore, the cross-linking reaction of the alkoxysilyl group in the hard segment can further improve the adhesiveness and heat resistance.

[0177] In addition, the block polymer structure has a polyether skeleton (PE skeleton), a crystalline polyester skeleton (PEs skeleton), and a methyl methacrylate copolymer skeleton (PAc skeleton), thereby becoming a compatibilizer for polyether, crystalline polyester, and methyl methacrylate copolymer, and can make crystalline polyester and methyl methacrylate copolymer, which are incompatible when alone, compatible.

[0178] (Weight ratio of each skeleton)

[0179] In component (ii), the weight ratio of the PE skeleton, the PEs skeleton, and the Pac skeleton, when the total of the PE skeleton, the PEs skeleton, and the Pac skeleton is set to 100 parts by weight, preferably the PE skeleton is more than 15 parts by weight and less than 55 parts by weight, preferably the PEs skeleton is more than 15 parts by weight and less than 50 parts by weight, and preferably the PAc skeleton is more than 10 parts by weight and less than 45 parts by weight.

[0180] (Compound having one active hydrogen group but no alkoxysilyl group)

[0181] By using a compound having one active hydrogen group reactive with an isocyanate group but not having an alkoxysilyl group (hereinafter referred to as a compound having only one active hydrogen group), the number of silyl groups in the alkoxysilyl-containing urethane prepolymer (A) can be adjusted (that is, reduced). This allows the crosslinking density of the alkoxysilyl-containing urethane prepolymer (A) after curing to be adjusted, and as a result, the softness and / or elongation of the cured film can be adjusted. Examples of active hydrogen groups reactive with isocyanate groups include hydroxyl groups, amino groups, and mercapto groups, with hydroxyl groups and amino groups being preferred. From the perspective of stably producing a moisture-curing hot-melt adhesive, secondary amino groups are more preferred. In addition, a compound having only one active hydrogen group can also be used as component (a3).

[0182] Examples of compounds having only one active hydrogen group include linear or branched alkyl alcohols such as 2-ethylhexanol, lauryl alcohol, stearyl alcohol, and behenyl alcohol; alcohols having functional groups other than hydroxyl groups such as propylene glycol monoacetate and diethylene glycol monoacetate; and alcohols having polyoxyalkylene chains such as polyoxypropylene monool. Examples of compounds having one amino group as an active hydrogen group include primary amines such as octylamine, laurylamine, cetylamine, stearylamine, and behenylamine; and secondary amines such as dibutylamine, butyloctylamine, dioctylamine, distearylamine, and butylstearylamine.

[0183] <Number of cross-linkable silicone groups>

[0184] The number of crosslinkable silicon groups in one molecule of the alkoxysilyl-containing urethane prepolymer (A) is preferably 1.0 or more on average, more preferably 1.2 or more on average, even more preferably 1.4 or more on average, and particularly preferably 1.6 or more on average, in terms of curability. From the viewpoint of physical properties, the number is preferably 4.0 or less on average, more preferably 3.0 or less on average, even more preferably 2.0 or less on average, and particularly preferably 1.8 or less on average.

[0185] <(B) Silane-based adhesion promoter>

[0186] The moisture-curable hot-melt adhesive of the present invention may further contain (B) a silane-based tackifier. The silane-based tackifier (B) exhibits a tackifier effect upon moisture curing, improving final strength, water-resistant adhesion, and heat-resistant adhesion in addition to condensation bond strength.

[0187] Here, from the viewpoint of hydrolysis rate, the alkoxysilyl group of the silane-based tackifier (B) is preferably a methoxy group, an ethoxy group, etc. However, the number of the alkoxy groups of the silyl group is preferably 2 or more, more preferably 3. Again, from the viewpoint of adhesion, the functional group of the silane-based tackifier (B) is preferably an amino group, an epoxy group, etc., more preferably an amino group. As the silane-based tackifier (B), aminosilane, ketimine silane, epoxy silane, acrylic silane silane, vinyl silane coupling agent, mercaptosilane, urea silane coupling agent, isocyanurate silane, isocyanate silane, etc. can be used.

[0188] Examples of aminosilanes include monosilylaminosilanes such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(β-aminoethyl)-3-aminopropyltrimethoxysilane, N-(β-aminoethyl)-3-aminopropyltriethoxysilane, and N-(β-aminoethyl)-3-aminopropylmethyldiethoxysilane; and bissilylaminosilanes such as bis(trimethoxysilylpropyl)amine, bis(triethoxysilylpropyl)amine, bis(triethoxysilylpropyl)ethylenediamine, N-[2-(vinylbenzylamino)ethyl]-3-aminopropyltrimethoxysilane, and aminoethyl-aminopropyltrimethoxysilane. Examples of ketimine silanes include N-(1,3-dimethylbutylene)-3-(triethoxysilyl)-1-propylamine. Examples of epoxysilanes include 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane. Examples of acrylic silanes include 3-methacryloyloxypropyltrimethoxysilane. Examples of vinylsilane coupling agents include vinyltrimethoxysilane, methylvinyldimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, and allyltri(β-methoxysilane). Examples of mercaptosilanes include 3-mercaptopropyltrimethoxysilane. Examples of ureasilane coupling agents include 3-ureidopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane. Examples of the isocyanate silane include tris(trimethoxysilylpropyl)isocyanate, and examples of the isocyanate silane include 3-isocyanatepropyltriethoxysilane.

[0189] Furthermore, examples of the silane-based tackifier (B) include aminosilane reactants such as reactants of the above-mentioned aminosilanes with epoxy silanes, reactants of aminosilanes with isocyanate silanes, reactants of aminosilanes with silanes having a (meth)acryloyloxy group, reactants of aminosilanes with epoxy resins (such as bisphenol A diglycidyl ether and phenylglycidyl ether), reactants of aminosilanes with polyisocyanates, and reactants of aminosilanes with polyacrylates; condensates formed by partially condensing the above-mentioned silanes (preferably aminosilane condensates formed by partially condensing the above-mentioned aminosilanes, isocyanate silanes, aminosilane reactants, and mixtures thereof); and modified derivatives thereof, namely, amino-modified silyl polymers, silylated amino polymers, unsaturated aminosilane complexes, phenylamino long-chain alkylsilanes, aminosilylated polysiloxanes, silylated polyesters, and photoaminosilane generators.

[0190] The molecular weight of the silane adhesive (B) is preferably 320 or higher, as it is less likely to volatilize during hot melt melting. A molecular weight of 400 or higher is more preferred, and 450 or higher is even more preferred. Due to their improved adhesion and the fact that the hot melt adhesive is less likely to volatilize during melting, silane adhesives having two or more silyl groups, such as bissilylaminosilane, triisocyanate silane, aminosilane reactants, and aminosilane condensates, are more preferred. Aminosilane reactants and aminosilane condensates are even more preferred, with aminosilane reactants being most preferred. Furthermore, the aminosilane reactant can also be reacted by adding the reactants separately during the mixing step.

[0191] (B) Silane tackifiers can be used alone or in combination of two or more. The amount of (B) silane tackifiers used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, particularly preferably 1 part by mass or more, preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less, relative to 100 parts by mass of component (A). If it is less than 0.01 parts by mass, the effect of imparting adhesion and the effect of serving as a curing catalyst are insufficient. On the other hand, if it exceeds 20 parts by mass, the effect of serving as a catalyst in response to the amount added is not significant and is economically unfavorable.

[0192] (Photoaminosilane generator)

[0193] When the hot-melt adhesive of the present invention is configured as a photocurable adhesive, a compound that does not generate an amino group before light irradiation but generates an amino group-containing silane upon light irradiation (hereinafter also referred to as a photoaminosilane generator) can be used. Examples of photoaminosilane generators include compounds described in WO2015-088021 whose photofunctional groups are o-nitrobenzyl, p-nitrobenzyl, oxime residue, benzyl, benzoyl, or substituted versions thereof. Examples of photoaminosilane generators whose photofunctional groups are o-nitrobenzyl include 2-nitrobenzyl-N-[3-(trimethoxysilyl)propyl]carbamate, 2-nitrobenzyl-N-[3-(triethoxysilyl)propyl]carbamate, and 3,4-dimethoxy-2-nitrobenzyl-N-[3-(trimethoxysilyl)propyl]carbamate. Examples of photoaminosilane generators whose photofunctional groups are p-nitrobenzyl groups include 4-nitrobenzyl-N-[3-(trimethoxysilyl)propyl]carbamate. Examples of photoaminosilane generators whose photofunctional groups are benzyl groups include 1-(3,5-dimethoxyphenyl)-1-methylethyl-N-[3-(trimethoxysilyl)propyl]carbamate. Examples of photoaminosilane generators whose photofunctional groups are oxime residues include benzophenone O-{[3-(trimethoxysilyl)propyl]}oxime.

[0194] <(C) Modified resin>

[0195] (C) Modified resins are added to control the bonding time of the blended system and reduce melt viscosity. They also have the function of modifying and adjusting physical properties. (C) Modified resins can improve bonding time and set adhesive strength.

[0196] Furthermore, component (C) of the present invention exhibits different functions depending on the type of segments that constitute the resin to which component (C) is added. Specifically, when component (C) is added to a resin primarily composed of hard segments, it functions as a modified resin, adjusting its physical properties. When added to a resin primarily composed of soft segments, it functions as a tackifying resin. Because the backbone of component (A) of the present invention is primarily composed of hard segments, the resins exemplified below function as modified resins.

[0197] Examples of the modified resin (C) include terpene resins, aromatic modified terpene resins and hydrogenated terpene resins obtained by hydrogenating the same, terpene-phenol resins obtained by copolymerizing terpenes with phenols, phenol resins, modified phenol resins, xylene-phenol resins, cyclopentadiene-phenol resins, coumarone-indene resins, rosin resins, rosin ester resins, hydrogenated rosin ester resins, xylene resins, low molecular weight polystyrene resins, styrene copolymer resins, styrene block copolymers, hydrogenated styrene block copolymers, petroleum resins (e.g., C5 hydrocarbon resins, C9 hydrocarbon resins, C5C9 hydrocarbon copolymer resins, etc.), hydrogenated petroleum resins, dicyclopentadiene (DCPD) resins, etc. These resins may be used alone or in combination of two or more.

[0198] Examples of styrene block copolymers and hydrogenated products thereof include styrene-butadiene-styrene block copolymers (SBS), styrene-isoprene-styrene block copolymers (SIS), styrene-ethylene butylene-styrene block copolymers (SEBS), styrene-ethylene propylene-styrene block copolymers (SEPS), and styrene-isobutylene-styrene block copolymers (SIBS).

[0199] From the perspectives of good compatibility with organic polymers having crosslinkable silicon groups and good thermal stability of the adhesive, the modified resin (C) is preferably a terpene-phenol resin or an aromatic petroleum resin. Aromatic petroleum resins are preferably aromatic styrene resins or aliphatic-aromatic copolymer styrene resins, with terpene-phenol resins and aliphatic-aromatic copolymer styrene resins being more preferred. Furthermore, from the perspectives of VOC and fogging, aliphatic-aromatic copolymer styrene resins are preferably used.

[0200] The amount of the modified resin (C) added relative to 100 parts by mass of component (A) is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, particularly preferably 30 parts by mass or more, and preferably 200 parts by mass or less, more preferably 150 parts by mass or less, particularly preferably 120 parts by mass or less.

[0201] <(D) Cross-linking catalyst>

[0202] Examples of the crosslinking catalyst (D) include crosslinking catalysts for alkoxysilyl-containing urethane prepolymers (silanol catalysts), such as titanates, tetravalent organotin compounds, divalent organotin compounds such as tin octoate, zirconium compounds, aluminum compounds, bismuth compounds, primary / secondary amine compounds, tertiary amine compounds such as benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, dimorpholinodiethyl ether, N,N-dimethyldodecylamine, and bis(N,N'-dimethylaminoethyl)ether, photolatent amine compounds (photobase generators), amidine compounds such as 1,3-diazabicyclo(5,4,6)undecene-7, or carboxylates thereof, and fluorinated polymers. These crosslinking catalysts (D) may be used alone or in combination of two or more.

[0203] Examples of fluorinated polymers include organic polymers having Si-F bonds, and examples include organic polymers having fluorosilyl groups as described in WO2015-088021 (hereinafter also referred to as "fluorinated polymers"). Fluorinated polymers are preferably polymers having fluorosilyl groups such as difluoromethylsilyl, difluoromethoxysilyl, difluoroethoxysilyl, or trifluorosilyl groups at the ends of the main chain or side chains.

[0204] As the main chain skeleton of the fluorinated polymer, the polymers described below in the liquid polymer compound section can be used. Among these polymers, polyoxyalkylene polymers and / or (meth)acrylate polymers are preferred due to their ease of handling and their significant effect in increasing the bonding time. The number average molecular weight of the fluorinated polymer is preferably 3,000 or more, preferably 100,000 or less, more preferably 50,000 or less, and particularly preferably 30,000 or less, as measured by GPC in terms of polystyrene.

[0205] When a fluorinated polymer is used, the amount thereof is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, and is preferably 80 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, relative to 100 parts by mass of the alkoxysilyl group-containing urethane prepolymer (A).

[0206] Furthermore, from the viewpoint of high catalytic effect and sufficient heat resistance, the crosslinking catalyst (D) is preferably a titanate ester, a tetravalent organotin compound, a divalent organotin compound, a tertiary amine compound, an amidine compound, or a carboxylate salt thereof, or a fluorinated polymer. In particular, from the viewpoint of being less susceptible to cleavage of silyl crosslinks by heat and moisture and less susceptible to deterioration of physical properties, the crosslinking catalyst (D) is preferably at least one catalyst selected from the group consisting of a tertiary amine compound, a divalent tin compound, a fluorinated polymer, and a titanate ester. More preferably, it is at least one catalyst selected from the group consisting of a tertiary amine compound, a divalent tin compound, and a fluorinated polymer. Fluorinated polymers are particularly preferred.

[0207] However, from the perspective of being less likely to cause transesterification reactions with low-molecular-weight alcohols (e.g., methanol or ethanol) due to the decomposition of polyester units and / or alkoxy terminal groups present in prepolymers such as component (A) (furthermore, hot-melt adhesives are melted in a heating oven prior to coating and remain in a liquid state for a relatively long period of time (generally, at least one working day), and therefore require sufficient stability at high temperatures for industrial use), divalent organotin compounds, tertiary amine compounds, and fluorinated polymers are preferred. Furthermore, when using a fluorinated polymer, its combined use with an alkoxysilane containing a ketimine structure further promotes the crosslinking reaction.

[0208] When a cross-linking catalyst other than the fluorinated polymer is used, the amount of the other cross-linking catalyst added is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.2 parts by mass or more, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, relative to 100 parts by mass of the alkoxysilyl group-containing urethane prepolymer (A).

[0209] (Photobase generator)

[0210] When the hot-melt adhesive of the present invention is configured as a photocurable adhesive, a photolatent amine compound that has no catalytic activity before light irradiation but generates an amine compound upon light irradiation can be used. The photolatent amine compound can be any of photolatent primary amines that generate an amine compound having a primary amino group upon the action of active energy rays, photolatent secondary amines that generate an amine compound having a secondary amino group upon the action of active energy rays, and photolatent tertiary amines that generate an amine compound having a tertiary amino group upon the action of active energy rays. Among these, photolatent tertiary amines are more preferred as photobase generators because the generated base exhibits high catalytic activity. Benzyl ammonium salt derivatives, benzyl-substituted amine derivatives, α-amino ketone derivatives, and α-ammonium ketone derivatives are preferred because they have good base generation efficiency and good storage stability as a composition. Benzyl ammonium salt derivatives and benzyl-substituted amine derivatives are particularly preferred because they do not generate a base without light irradiation but efficiently generate a base upon light irradiation. Specifically, the various photobase generators described in International Publication No. WO2015 / 008709 can be used. These photobase generators may be used alone or in combination of two or more.

[0211] <(E) Silylated polymer>

[0212] (E) Silylated polymers are added to reactive hot-melt adhesives to control their lamination time and reduce their melt viscosity. They also modify and / or adjust the properties of the reactive hot-melt adhesive. Silylated polymers can improve coating workability and coagulation strength.

[0213] Examples of silylated polymers include silylated polyurethanes and silyl-terminated polymers. Examples of silylated polyurethanes include silylated polyurethane 1 and silylated polyurethane 2, described in detail below. From the perspective of achieving a strong and resilient cured product and good reactivity, silylated polyurethanes are preferred, with silylated polyurethane 2 being more preferred. Furthermore, from the perspective of reducing the melt viscosity of the adhesive and improving coating workability, silyl-terminated polymers and silylated polyurethane 1 are preferred, with silyl-terminated polymers being more preferred.

[0214] Furthermore, from the viewpoint of improving the coating workability, lamination time, coagulation strength, and final strength of the adhesive, a silylated polyurethane having a crystalline aliphatic polyester skeleton and / or a crystalline polycarbonate skeleton that is solid at room temperature is preferred, a silylated polyurethane having a crystalline aliphatic polyester skeleton is more preferred, and a silylated polyurethane having a long-chain aliphatic polyester skeleton is even more preferred.

[0215] However, from the perspective of reducing the melt viscosity of the adhesive and improving the flexibility of the cured film, silylated polymers with a polyoxyalkylene backbone that are liquid at room temperature are preferred, silylated polymers with a polyoxypropylene backbone are more preferred, and silyl-terminated polyethers with a polyoxypropylene backbone are even more preferred. From the perspective of enhancing the effect of reducing the melt viscosity of the adhesive, long-chain alkyl polyesters with a number average molecular weight of 1,000 to 2,000 are particularly preferred. Furthermore, from the perspective of further improving the adhesive's adhesion to aromatic resins such as polyethylene terephthalate and imparting toughness to increase ultimate strength, silylated polyurethanes with an aromatic polyester backbone are preferred, and silylated polyurethanes with an aromatic polyester backbone that are solid at room temperature are more preferred. From the perspective of reducing the melt viscosity, aromatic polyesters with a number average molecular weight of 1,000 to 2,000 are particularly preferred.

[0216] Specifically, the silylated polymer is an organic polymer having a crosslinkable silicon group. As the crosslinkable silicon group, the group represented by the general formula (IX) described in the item "methyl methacrylate polymer containing an alkoxysilyl group" described later can be cited. In addition, when the silylated polymer has multiple crosslinkable silicon groups, the crosslinkable silicon group may be one type, or two or more types may be used in combination. The crosslinkable silicon group may also be bonded to the main chain or side chain of the polymer, or to both. From the viewpoint of excellent physical properties of the cured product, such as the tensile properties of the cured product, it is preferred that the crosslinkable silicon group be present at the end of the molecular chain.

[0217] The number of crosslinkable silicon groups present in one silylated polymer molecule is preferably from 1.0 to 5, more preferably from 1.1 to 3. If the number of crosslinkable silicon groups in the molecule is less than 1, the curability becomes insufficient. On the other hand, if the number is too large, the network structure becomes too dense, and thus good mechanical properties cannot be exhibited.

[0218] Furthermore, when a cross-linkable silicon group is present at the end of the molecular chain, the blending ratio of the component containing the molecular chain end group to the component containing the cross-linkable silicon group is preferably 0.3 moles or more of the cross-linkable silicon group relative to 1 mole of the molecular chain end group, more preferably 0.5 moles or more, and even more preferably 0.7 moles or more. Furthermore, the component containing the cross-linkable silicon group may be added excessively relative to the molecular chain end group. In this case, the excess cross-linkable silicon group-containing component functions as a tackifier. Furthermore, when unreacted hydroxyl groups remain, it is preferred to react a monoisocyanate with the unreacted hydroxyl groups to deactivate them. As monoisocyanates, monoisocyanates having an isocyanate group bonded to a C6-C18 alkyl group or a C6-C18 aryl group can be cited, preferably, for example, stearyl isocyanate, phenyl isocyanate, and naphthyl isocyanate.

[0219] [Silylated polyurethane 1]

[0220] Silylated polyurethane 1 can be prepared by reacting isocyanate silane with a polymer having a hydroxyl group. Silylated polyurethane 1 is prepared by reacting isocyanate silane with a polyester polyol, polycarbonate polyol, or polyoxyalkylene polyol as a polymer having a hydroxyl group. Examples include silylated polyester urethane 1 having a polyester skeleton, silylated polycarbonate urethane 1 having a polycarbonate skeleton, and silylated polyether urethane 1 having a polyoxyalkylene skeleton. Furthermore, the polymer having a hydroxyl group may be a polymer having a hydroxyl group linked via a diisocyanate.

[0221] [Silylated polyurethane 2]

[0222] Silylated polyurethane 2 can be prepared by reacting an alkoxysilane having an active hydrogen group with a polyurethane polymer containing an isocyanate group. Preferably, the reaction is carried out using a reactive group having a stoichiometric ratio of 1:1 of active hydrogen groups to isocyanate groups, or a slightly excessive ratio of isocyanate groups, so that the resulting silylated polyurethane 2 contains no isocyanate groups at all. Polyurethane polymers containing isocyanate groups can be prepared, for example, by reacting various polyols with diisocyanates. Specifically, silylated polyether urethane 2 having a polyoxyalkylene skeleton using a polyoxyalkylene polyol as the polyol can be used.

[0223] Suitable polyols include, in particular, polyether polyols, polyester polyols, and polycarbonate polyols, and mixtures of these polyols, preferably polyoxyalkylene polyols.

[0224] [Silyl-terminated polymer]

[0225] Silyl-terminated polymers can be prepared by hydrosilylation of a polymer having a double bond at the terminal. The polymer having a double bond at the terminal is a poly(meth)acrylate polymer or a polyether polymer, and examples thereof include silyl-terminated polyethers having a polyoxyalkylene skeleton and silyl-terminated polyacrylates having a polyacrylate skeleton.

[0226] [Silyl-terminated polyether]

[0227] Silyl-terminated polyethers are obtained, for example, by reacting a polyoxyalkylene polymer containing an unsaturated group with a hydrosilane having a crosslinkable silicon group or a mercapto compound having a crosslinkable silicon group, followed by hydrosilylation or mercaptolation. This synthesis method is a method for obtaining a polyoxyalkylene polymer having a crosslinkable silicon group (silyl-terminated polyether), and an example thereof is the preparation of an allyl-terminated polyoxyalkylene polymer described in Japanese Patent Application Laid-Open No. 2006-077036 by hydrosilylation. Polyoxyalkylene polymers containing unsaturated groups can be prepared by reacting an organic polymer having a functional group such as a hydroxyl group with an organic compound having an active group reactive with the functional group and an unsaturated group.

[0228] [Silyl-terminated polyacrylate]

[0229] Silyl-terminated polyacrylates are composed of at least one acrylate component and at least one silyl component. Silyl-terminated polyacrylates are obtained, for example, by reacting alkenyl-terminated acrylates with hydrosilylation. Alternatively, alkenyl-terminated acrylates are obtained by a production method using atom transfer radical polymerization (ATRP) or a production method utilizing the reaction of an alkyl-terminated acrylate with a monomer containing a silyl group. Alkenyl-terminated acrylates are obtained by a production method utilizing atom transfer radical polymerization (ATRP). Silyl-terminated polyacrylates are preferably silyl-terminated polyacrylates containing butyl acrylate as a main component that are liquid at room temperature and have flexibility.

[0230] [Polyoxyalkylene polymers]

[0231] As the main skeleton of the polyoxyalkylene polyol and the unsaturated group-containing polyoxyalkylene polymer, a polyoxyalkylene polymer having a repeating unit represented by the following general formula (α) is preferred.

[0232] -R β -O- (α)

[0233] Here, in the general formula (α), R β It represents a linear or branched alkylene group having 1 to 14 carbon atoms, preferably 2 to 4 carbon atoms.

[0234] The main chain of the polyoxyalkylene polymer may be composed of only one type of repeating unit or may be composed of two or more types of repeating units. In particular, in the present invention, amorphous and relatively low-viscosity polyoxypropylene polymers are preferred.

[0235] Examples of methods for synthesizing polyoxyalkylene polymers include polymerization methods using a base catalyst such as KOH, polymerization methods using a composite metal cyanide complex catalyst (e.g., a zinc hexacyanocobaltate-glyme complex catalyst), etc. Among these, polymerization methods in which an alkylene oxide is reacted with an initiator in the presence of a composite metal cyanide complex catalyst are preferred because they allow the synthesis of a polymer having a narrow molecular weight distribution.

[0236] Examples of the composite metal cyanide complex catalyst include Zn3[Co(CN)6]2 (zinc hexacyanocobaltate complex), etc. Catalysts in which alcohols and / or ethers are coordinated as organic ligands to these catalysts may also be used.

[0237] The initiator is preferably a compound having at least two active hydrogen groups. Examples of active hydrogen-containing compounds include polyols such as ethylene glycol, diethylene glycol, propylene glycol, and glycerol, and linear and / or branched polyether compounds having a number average molecular weight of 500 to 20,000.

[0238] Examples of the alkylene oxide include ethylene oxide, propylene oxide, and isobutylene oxide.

[0239] As the polyoxyalkylene polyol, particularly preferably, polyoxyethylene polyol and polyoxypropylene polyol are mentioned, and among these, polyoxyethylene diol, polyoxypropylene diol, polyoxyethylene triol, and polyoxypropylene triol are mentioned.

[0240] Among these, preferred are polyoxyalkylene diols or polyoxyalkylene triols having an unsaturation degree of less than 0.02 mEq / g and a molecular weight in the range of 1,000 g / mol to 30,000 g / mol; and polyoxyethylene diols, polyoxyethylene triols, polyoxypropylene diols, and polyoxypropylene triols having a molecular weight in the range of 400 g / mol to 8,000 g / mol.

[0241] Here, the so-called polyoxypropylene polyol terminated with ethylene oxide (i.e., an "EO-capped" compound; an "ethylene oxide end-capped" compound) is particularly preferred. EO-capped polyoxypropylene polyol is a special polyoxypropylene polyoxyethylene polyol. For example, it is prepared by additionally alkoxylating pure polyoxypropylene polyol, especially polyoxypropylene diol and triol, with ethylene oxide after the polyoxypropylation reaction is completed. As a result, it has primary hydroxyl groups. Furthermore, although polypropylene glycol (PPG) has secondary hydroxyl groups and is flexible, its reactivity is inferior to that of compounds having primary hydroxyl groups. Therefore, in the present invention, it is preferred to improve reactivity by using an EO-capped compound having primary hydroxyl groups. In this case, it is preferred to use polyoxypropylene polyoxyethylene diol and / or polyoxypropylene polyoxyethylene triol.

[0242] The polyol as described above preferably has an average molecular weight of 250 g / mol to 30,000 g / mol, particularly preferably 1,000 g / mol to 30,000 g / mol, and an average OH functionality within the range of 1.6 to 3.

[0243] The polyol is preferably a polyether polyol, more preferably polyoxyethylene polyol, polyoxypropylene polyol, and polyoxypropylene polyoxyethylene polyol, and still more preferably polyoxyethylene diol, polyoxypropylene diol, polyoxyethylene triol, polyoxypropylene triol, polyoxypropylene polyoxyethylene diol, and polyoxypropylene polyoxyethylene triol.

[0244] <Alkoxysilyl group-containing methyl methacrylate polymers>

[0245] Component (A) may also contain an alkoxysilyl-containing methyl methacrylate polymer. Alkoxysilyl-containing methyl methacrylate polymers are (meth)acrylate polymers containing methyl methacrylate as an essential monomer. Alkoxysilyl-containing methyl methacrylate polymers can impart toughness to moisture-curing hot-melt adhesives and improve both coagulation strength and ultimate strength. Furthermore, the heat resistance of moisture-curing hot-melt adhesives can be enhanced through cross-linking reactions of the alkoxysilyl groups.

[0246] The alkoxysilyl group of the (meth)acrylate polymer having an alkoxysilyl group and having a glass transition temperature of -20°C to 120°C is a group having an alkoxy group bonded to a silicon atom and capable of crosslinking via a silanol condensation reaction, wherein the (meth)acrylate polymer is a methyl methacrylate polymer containing an alkoxysilyl group. Examples of the alkoxysilyl group include groups represented by the following general formula (IX).

[0247]

[0248] In the general formula (IX), R 11 represents an alkyl group having 1 to 20 carbon atoms, a substituted alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and R 11 When there are two or more X groups, they may be the same or different. X represents an alkoxy group, and when there are two or more X groups, they may be the same or different. a represents 0, 1, 2, or 3. In the alkoxysilyl group of general formula (IX), a is preferably 2 or 3. When a is 3, the curing speed is faster than when a is 2.

[0249] As R 11 Specific examples include alkyl groups such as methyl and ethyl, substituted alkyl groups such as methoxymethyl, and cycloalkyl groups such as cyclohexyl. Among these, methyl is preferred, and substituted alkyl groups in which the α carbon is substituted with a polar group are preferred from the viewpoint of increasing the curing speed.

[0250] The alkoxy group represented by X is not particularly limited, as long as it is a conventionally known alkoxy group. Among alkoxy groups, those with fewer carbon atoms are more reactive, and the reactivity decreases with increasing carbon atoms, in the order of methoxy > ethoxy > propoxy. While the type of alkoxy group can be selected depending on the purpose and application, a methoxy or ethoxy group is generally used. In the case of the alkoxysilyl group represented by general formula (IX), considering curability, a is preferably 2 or greater.

[0251] Specifically, from the viewpoint of high reactivity, the alkoxysilyl group is preferably a trimethoxysilyl group or a triethoxysilyl group, more preferably a trimethoxysilyl group, and from the viewpoint of obtaining a flexible cured product, preferably a methyldimethoxysilyl group or a methyldiethoxysilyl group.

[0252] The alkoxysilyl group may be used alone or in combination of two or more. The alkoxysilyl group may be present in the main chain or the side chain, or in both.

[0253] The number (average value) of alkoxysilyl groups in the alkoxysilyl-containing methyl methacrylate polymer is preferably 0.3 or more per polymer molecule, more preferably 0.5 or more, even more preferably 1 or more, and preferably 5 or less, more preferably 3 or less, and even more preferably 2.5 or less. If the number of alkoxysilyl groups contained in the molecule is less than 0.3, the curing properties become insufficient, while if it is too high, the network structure becomes too dense, and thus good mechanical properties cannot be exhibited.

[0254] In the preparation of the methyl methacrylate polymer containing an alkoxysilyl group, various known methods can be used to introduce the alkoxysilyl group into the (meth)acrylate polymer. For example, the following methods can be mentioned as examples of methods for introducing the alkoxysilyl group.

[0255] (1) Copolymerizing an unsaturated compound having an alkoxysilyl group.

[0256] (2) Polymerization is carried out using an initiator or a chain transfer agent having an alkoxysilyl group.

[0257] (3) A (meth)acrylate polymer having a functional group such as a hydroxyl group is reacted with a compound having another functional group reactive with the functional group, such as epoxysilane, and an alkoxysilyl group.

[0258] From the viewpoint of easy introduction of alkoxysilyl groups, among these methods for introducing alkoxysilyl groups, the method of (1) copolymerizing an unsaturated compound having an alkoxysilyl group is preferred. In addition, a method of combining the method (1) and the method (2) is also preferred. For example, methyl methacrylate, 2-ethylhexyl methacrylate, 3-methacryloyloxypropyltrimethoxysilane, dichlorotitanocene as a metal catalyst, 3-mercaptopropyltrimethoxysilane (which acts as an initiator and a chain transfer agent through the action of dichlorotitanocene), and a quinone solution as a polymerization terminator are used, and the synthesis method according to Synthesis Example 4 of WO2015-088021 is used to obtain a trimethoxysilyl-containing (meth)acrylic polymer as a methyl methacrylate-based polymer containing an alkoxysilyl group.

[0259] (Unsaturated compound having an alkoxysilyl group)

[0260] As the unsaturated compound with an alkoxysilyl group used in the copolymerization, preferably an alkoxysilyl group having an alkoxysilyl group (meth) alkyl acrylate or vinyl silane. As such a compound, for example, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, etc., vinyl alkoxysilane such as vinyltriethoxysilane, etc. can be cited. Among these, preferably, an alkoxysilyl group having an alkyl group having a carbon number of 3 or less substituted alkyl group is used. The blending ratio of the unsaturated compound with an alkoxysilyl group is preferably such that the average number of alkoxysilyl groups having an unsaturated bond of an alkoxysilyl group is 1.1 or more and 5 or less, preferably 1.1 or more and 3 or less, relative to the alkoxysilyl group per polymer molecule of the methyl methacrylate-based polymer containing the alkoxysilyl group.

[0261] (Monomers other than the monomer having an alkoxysilyl group used for the methyl methacrylate-based polymer containing an alkoxysilyl group)

[0262] Examples of monomers other than the monomer having an alkoxysilyl group used in the alkoxysilyl-containing methyl methacrylate polymer include methyl methacrylate-based random copolymers having repeating units represented by the general formula (X) containing methyl methacrylate as an essential monomer component.

[0263] -CH2C(R 12 )(COOR 13 )- (X)

[0264] In the general formula (X), R 12 represents a hydrogen atom or a methyl group, R 13 It represents a hydrocarbon group which may further have a substituent. In addition, the (meth)acrylate refers to an acrylate and / or an alkyl methacrylate.

[0265] As a monomer forming a repeating unit other than methyl methacrylate (MMA), an alkyl (meth)acrylate is preferably used. Examples of the alkyl (meth)acrylate compound include well-known compounds. Examples thereof include methyl acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate.

[0266] From the perspective of good compatibility with the polyether backbone of the isocyanate-terminated urethane prepolymer having a polyether backbone (i.e., part of the backbone of component (A)), preferably used are alkyl (meth)acrylates having an ester bond with 8 or more carbon atoms, such as 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate. From the perspective of softening the methyl methacrylate-based polymer, preferably used are alkyl (meth)acrylates having a glass transition temperature (Tg) of 0°C or less, such as n-butyl acrylate (Tg: -55°C), 2-ethylhexyl acrylate (Tg: -70°C), and lauryl acrylate (Tg: -3°C). The glass transition temperature in this paragraph refers to the glass transition temperature of the homopolymer.

[0267] The hydrocarbon group, such as the alkyl group, of the (meth)acrylate may also have a substituent such as a hydroxyl group, an alkoxy group, a halogen atom, or an epoxy group. Examples of the aforementioned compounds include (meth)acrylates having a hydroxyl group, such as hydroxyethyl (meth)acrylate, (meth)acrylates having an alkoxy group, such as methoxyethyl (meth)acrylate, (meth)acrylates having an epoxy group, such as glycidyl (meth)acrylate, and (meth)acrylates having an amino group, such as diethylaminoethyl (meth)acrylate. Furthermore, unsaturated compounds having a high molecular weight chain (macromonomer or macromer), such as acrylates having a polystyrene chain, may also be used.

[0268] Furthermore, the alkoxysilyl-containing (meth)acrylate polymer of the alkoxysilyl-containing methyl methacrylate polymer may contain, in addition to repeating units derived from (meth)acrylate compounds, repeating units derived from compounds copolymerizable with these compounds. Examples of compounds copolymerizable with (meth)acrylate compounds include acrylic acids such as (meth)acrylic acid; amide compounds such as (meth)acrylamide; vinyl ether compounds such as alkyl vinyl ethers; and other esters such as acrylonitrile, styrene, α-methylstyrene, vinyl chloride, and vinyl acetate.

[0269] (Monomer usage ratio)

[0270] The amount of monomer used in the alkoxysilyl-containing methyl methacrylate polymer is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and optimally 95% by mass or more. In particular, it is preferred to use an unsubstituted alkyl acrylate having an alkyl group with 2 to 30 carbon atoms, such as methyl methacrylate and butyl acrylate, in the above amount. Furthermore, a macromonomer may be used as a monomer in the alkoxysilyl-containing methyl methacrylate polymer. However, when using a macromonomer, the amount of the macromonomer in the alkoxysilyl-containing methyl methacrylate polymer is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less.

[0271] (Glass transition temperature)

[0272] The alkoxysilyl-containing methyl methacrylate polymer has a glass transition temperature (Tg) of -20°C to 120°C. The glass transition temperature is preferably -20°C or higher, more preferably 0°C or higher, further preferably 20°C or higher, preferably 120°C or lower, more preferably 100°C or lower, and further preferably 80°C or lower. If the glass transition temperature is lower than -20°C, the bonding strength immediately after bonding tends to be poor. If the glass transition temperature exceeds 120°C, the melt viscosity becomes high, and it tends to be difficult to apply the hot melt adhesive to the adherend. The glass transition temperature can be easily estimated using the following Fox formula from the type and amount of the monomer components.

[0273] 1 / Tg=W1 / Tg1+W2 / Tg2+...+W n / Tg n (Fox style)

[0274] In the above Fox formula, Tg is the glass transition temperature of the acrylic resin (K), W1, W2, ..., W n is the weight fraction of each monomer, Tg1, Tg2, ..., Tg n is the glass transition temperature of the homopolymer of each monomer. The glass transition temperature of the homopolymer used in the Fox equation can be a value listed in the literature, for example, in the Acrylate Catalog (1997 edition) of Mitsubishi Rayon Co., Ltd. or in "New Polymer Library 7: Introduction to Synthetic Resins for Coatings," by Kyozo Kitaoka, Polymer Publishing Society, pp. 168-169.

[0275] The molecular weight of the alkoxysilyl-containing methyl methacrylate polymer of the alkoxysilyl-containing (meth)acrylate polymer is preferably a number average molecular weight (polystyrene-equivalent molecular weight measured by GPC) of 3,000 or greater, more preferably 4,000 or greater, and even more preferably 5,000 or greater, and preferably 200,000 or less, more preferably 100,000 or less, and even more preferably 50,000 or less. A number average molecular weight of less than 3,000 results in low initial adhesion after coating, while a number average molecular weight exceeding 200,000 results in excessively high viscosity during coating, impairing workability. Furthermore, the alkoxysilyl-containing methyl methacrylate polymer is preferably solid at room temperature.

[0276] (Polymerization method of methyl methacrylate polymer containing alkoxysilyl group)

[0277] As a polymerization method for the alkoxysilyl-containing methyl methacrylate polymer, a free radical polymerization method can be used. For example, conventional solution polymerization methods or bulk polymerization methods using thermal polymerization initiators such as benzoyl peroxide and azobisisobutyronitrile can be used. Alternatively, polymerization methods using a photopolymerization initiator and irradiation with light or radiation can be used. In free radical copolymerization, chain transfer agents such as lauryl mercaptan and 3-mercaptopropyltrimethoxysilane can be used to adjust the molecular weight. Alternatively, a free radical polymerization method using a thermal polymerization initiator can be used, and using this method, the alkoxysilyl-containing methyl methacrylate polymer of the present invention can be easily obtained. Furthermore, other polymerization methods such as the living free radical polymerization method described in Japanese Patent Application Laid-Open No. 2000-086998 can also be used.

[0278] <Other additives>

[0279] The reactive hot-melt adhesive of the present invention may optionally contain other additives. Examples of such additives include liquid polymers, fillers, diluents, stabilizers, flame retardants, curing modifiers, free radical inhibitors, metal inert agents, ozone inhibitors, phosphorus peroxide decomposers, glidants, pigments, foaming agents, and mildew inhibitors. These additives may be used alone or in combination of two or more.

[0280] (Liquid polymer compound)

[0281] Liquid polymer compounds have the effect of reducing the viscosity of hot-melt adhesives when molten. Furthermore, liquid polymer compounds have the effect of increasing the bonding time (the time it takes to bond after hot-melt coating). The viscosity of the liquid polymer compound at room temperature (B-type viscometer) is preferably 100 Pa·s or less, more preferably 75 Pa·s or less, and particularly preferably 50 Pa·s or less.

[0282] Examples of the main chain backbone of the liquid polymer compound include polyoxyalkylene polymers such as polyoxypropylene, polytetrahydrofuran, and polyoxyethylene-polyoxypropylene copolymers; hydrocarbon polymers such as ethylene-propylene polymers, polyisobutylene, polyisoprene, polybutadiene, and hydrogenated polyolefin polymers obtained by hydrogenating these polyolefin polymers; polyester polymers obtained by condensing a dibasic acid such as adipic acid with a diol, or by ring-opening polymerization of lactones; (meth)acrylate polymers obtained by free radical polymerization of monomers such as ethyl (meth)acrylate and butyl (meth)acrylate; vinyl polymers obtained by free radical polymerization of (meth)acrylate monomers, vinyl acetate, acrylonitrile, and styrene; graft polymers obtained by polymerizing vinyl monomers in organic polymers; polysulfide polymers; polyamide polymers; polycarbonate polymers; and diallyl phthalate polymers. Two or more of these backbones may be included in blocks or randomly. Among these polymers, polyoxyalkylene polymers and / or (meth)acrylate polymers are preferred because they are easy to handle and have a significant effect of increasing the lamination time.

[0283] If too much liquid polymer compound is used, the properties of the hot melt adhesive, such as heat resistance, may be impaired. Therefore, the content of the liquid polymer compound is preferably 0 parts by mass or more, preferably 100 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 30 parts by mass or less, based on 100 parts by mass of component (A).

[0284] (filler)

[0285] Examples of fillers include calcium carbonate, magnesium carbonate, titanium oxide, carbon black, fused silica, precipitated silica, diatomaceous earth, clay, kaolin, clay, talc, sawdust, walnut shell powder, rice husk powder, silicic anhydride, quartz powder, aluminum powder, zinc powder, asbestos, glass fiber, carbon fiber, glass beads, aluminum oxide, hollow glass spheres, hollow white sand spheres, hollow silica spheres, inorganic fillers such as calcium oxide, magnesium oxide, and silicon oxide; wood fillers such as pulp and kapok dust; and organic fillers such as powdered rubber, recycled rubber, fine powders of thermoplastic or thermosetting resins, and hollow bodies of polyethylene. The fillers may be added alone or in combination.

[0286] (Thinner)

[0287] By adding a diluent to the reactive hot-melt adhesive of the present invention, physical properties such as viscosity can be adjusted. Since the adhesive is used (applying and melting) at high temperatures, a solvent (diluent) with a boiling point of 150°C or higher is preferably used from the perspective of safety (fire and health). The boiling point of the diluent is preferably 150°C or higher, more preferably 200°C or higher, and even more preferably 300°C or higher.

[0288] Examples of the diluent include phthalates such as dioctyl phthalate and diisodecyl phthalate; aliphatic dibasic acid esters such as dimethyl adipate and dioctyl adipate; polyethers such as polypropylene glycol or its derivatives; vinyl polymers obtained by polymerizing vinyl monomers by various methods, paraffin process oils, naphthenic oils, and other oils; synthetic waxes such as Fischer Tropsch wax, polyethylene wax, polypropylene wax, and heterocyclic polypropylene; and petroleum waxes such as paraffin wax and microcrystalline wax. These diluents may be used alone or in combination of two or more.

[0289] The reactive hot-melt adhesive of the present invention preferably avoids adding a solvent having a boiling point of 120° C. or lower, 150° C. or lower, or 200° C. or lower.

[0290] (Stabilizer)

[0291] Examples of stabilizers include antioxidants, light stabilizers, and ultraviolet absorbers. The use of antioxidants can improve the weather resistance and heat resistance of the cured product. Examples of antioxidants include hindered phenols, monophenols, bisphenols, and polyphenols, with hindered phenols being particularly preferred. The use of light stabilizers can prevent photooxidative degradation of the cured product. Examples of light stabilizers include benzotriazoles, hindered amines, and benzoate compounds, with hindered amines being particularly preferred. The use of ultraviolet absorbers can improve the surface weather resistance of the cured product. Examples of ultraviolet absorbers include benzophenones, benzotriazoles, salicylates, substituted tolyls, and metal chelate compounds, with benzotriazoles being particularly preferred. Furthermore, it is preferred to use phenols and hindered phenol antioxidants in combination with hindered amine light stabilizers and benzotriazole ultraviolet absorbers.

[0292] (flame retardant)

[0293] Examples of the flame retardant include linear phosphazenes and cyclic phosphazenes described in JP-A-2002-519463, and phenoxyphosphazenes are preferred.

[0294] Examples of flame retardants include organic halides such as decabromobisphenyl ether and tetrabromobisphenol; inorganic halides such as ammonium bromide; tertiary phosphines such as triarylphosphine, trialkylphosphine, bis(diarylphosphino)benzene, and tri(diarylphosphino)benzene; organic metal phosphates such as tris(diethylphosphonate); inorganic phosphorus-nitrogen compounds such as ammonium polyphosphate and melamine polyphosphate; nitrogen compounds such as melamine and melamine / formaldehyde resin; inorganic hydroxides such as magnesium hydroxide and aluminum hydroxide; and inorganic compounds such as antimony oxide, hydroxoantimonate, zirconium oxide, zirconium hydroxide, molybdenum oxide, ammonium molybdate, zinc borate, ammonium borate, barium metaborate, talc, silicates, silicon oxide, tin oxide, and siloxane compounds.

[0295] <Content of component (A)>

[0296] The reactive hot-melt adhesive of the present invention preferably contains 50% by mass or more of component (A), more preferably 60% by mass or more, and particularly preferably 70% by mass or more in view of the properties of the hot-melt adhesive.

[0297] <Method for preparing moisture-curing hot-melt adhesives>

[0298] The reactive hot-melt adhesive of the present invention can be prepared as a one-component type in which all the ingredients (e.g., component (A), component (B), component (C), component (D), component (E), and / or other additives) are pre-blended and sealed, and then cured by atmospheric moisture after application. Alternatively, a two-component type can be prepared in which a mixture of components (A), (C), (E), and / or other additives is mixed with a mixture of components (B) and (D) before use.

[0299] The preparation method of the reactive hot melt adhesive of the present invention is not particularly limited, and conventional methods may be used, for example, by mixing the above-mentioned components in a specified blending ratio, kneading them at room temperature or under heating using a mixer, roller, kneader, etc., or dissolving the components in a small amount of a specified solvent and mixing them.

[0300] The viscosity of the reactive hot-melt adhesive of the present invention at 120°C is preferably 400 Pa·s or less, more preferably 200 Pa·s or less, even more preferably 100 Pa·s or less, and particularly preferably 50 Pa·s or less. If the viscosity at 120°C exceeds 400 Pa·s, coating and workability may be impaired, or coating may require higher temperatures to ensure coating and workability. This can make application difficult on substrates with low heat resistance, limiting the scope of application.

[0301] <Application>

[0302] The moisture-curing hot-melt adhesive of the present invention exhibits excellent drop impact resistance, water resistance, flexibility, and shape retention after application. Therefore, it is suitable for bonding various substrates, including metals, resins, paper, wood, stone, and concrete. Specifically, it can be used in production lines for applications such as construction, building materials, automotive, electrical / electronic components (e.g., lamination of optical components), and fiber, leather, clothing, and bookbinding. Furthermore, it can be used in off-line applications such as on-site construction at construction sites and DIY projects.

[0303] Examples of applications for bonding optical components include sealants for mobile phones, smartphones, and other mobile information terminals, personal computers, tablet computers, and other information processing terminals, game consoles, televisions, car navigation systems, cameras, speakers, and head-mounted displays. Furthermore, the moisture-curable hot-melt adhesive of the present invention can also be used as a sealant, coating agent, or potting agent.

[0304] <Application Method of Moisture-Curing Hot Melt Adhesive>

[0305] The moisture-curable silylated polyurethane adhesive of the present invention can be applied using methods similar to those used for various known reactive hot-melt adhesives. For example, the application method comprises heating the moisture-curable silylated polyurethane adhesive of the present invention to a predetermined temperature (heating step), applying the heated adhesive to the bonding area of a first adherend (applying step), and laminating a second adherend to the first adherend so as to sandwich the adhesive (laminating step). Furthermore, in the coating step, the adhesive of the present invention can be applied not only to the first adherend but also to the bonding area of the second adherend.

[0306] Specifically, when bonding one substrate to another using the moisture-curable hot melt adhesive of the present invention, the moisture-curable hot melt adhesive is heated to melt at a temperature between 50°C and 130°C, and the melted adhesive is applied to one substrate. The other substrate is then bonded to the melted adhesive and moisture-cured. This results in a laminate in which the substrates are bonded to each other via the moisture-curable hot melt adhesive.

[0307] Furthermore, examples of the metal substrate include: single metal substances such as iron, nickel, chromium, aluminum, magnesium, copper, and lead; alloys such as stainless steel and brass obtained from the aforementioned single metal substances; plated metals such as iron plated with zinc, nickel, chromium, and the like; and chemically treated metals such as chromate treatment and phosphate treatment for the aforementioned single metal substances, alloys, or plated metals.

[0308] Examples of the resin substrate include glass, polyamide resin, polyimide resin, polyamideimide resin, acrylic resin, urethane resin, silicone resin, epoxy resin, fluororesin, polystyrene resin, polyester resin, polysulfone resin, polyethersulfone resin, polyarylate resin, polyvinyl chloride resin, polyvinylidene chloride, norbornene resin, polyolefin resin, alicyclic polyimide resin, cellulose resin, POM (polyacetal), PEEK (polyetheretherketone), PC (polycarbonate), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), POB (polyoxybenzoyl), modified PPE (polyphenylene ether), PEN (polyethylene naphthalate), PEI (polyetherimide), PET (polyethylene terephthalate), LCP (liquid crystal polyester), lactic acid polymer, ABS resin, AS resin, etc. Furthermore, the substrate may be subjected to pre-treatments such as corona treatment, plasma treatment, and primer treatment as needed.

[0309] (Coating method)

[0310] Examples of methods for applying a moisture-curing hot-melt adhesive to a substrate include methods using a roll coater, spray coater, T-die coater, knife coater, notch wheel coater, etc.; and methods of applying the adhesive by a dispenser, inkjet printing, screen printing, lithographic printing, etc.

[0311] The latter application method, such as a dispenser, allows precise application of a small amount of moisture-curing hot-melt adhesive to the desired application location on the substrate, thus preventing losses from punching and other processes, making it preferable. Dispensers, in particular, are suitable for application methods that process compositions that are highly curable at room temperature, due to their excellent thermal stability within a sealed heating tank (liquid delivery tank). Furthermore, this application method allows the moisture-curing hot-melt adhesive to be applied continuously or intermittently to the substrate in a variety of shapes, including dots, lines, dotted lines, dashed-dotted lines, triangles, squares, and other polygonal shapes, as well as circles, ellipses, and curved lines.

[0312] The thickness of the adhesive layer using a moisture-curable hot-melt adhesive can be appropriately set according to the intended use. As an example, the thickness of the adhesive layer is in the range of about 10 μm to 5 mm.

[0313] The aging conditions for moisture curing after lamination are, for example, a temperature of 20° C. to 80° C., a humidity of 50% to 90%, and a period of about 0.5 to 5 days.

[0314] The above method yields a laminate comprising multiple substrates and an adhesive layer composed of an adhesive obtained by moisture-curing a moisture-curing hot-melt adhesive. From the perspective of ease of manual peeling, the laminate is preferably heated to a temperature between 40°C and 150°C to remove the adhesive layer from the laminate and recover the substrates.

[0315] <Effects of the implementation form>

[0316] The moisture-curable hot-melt adhesive of the present invention, comprising an alkoxysilyl-containing urethane prepolymer (A) of a specific structure, exhibits both excellent coagulation strength and a sufficiently long bonding time. Furthermore, the reactive hot-melt adhesive of the present invention is also suitable for adherends having curved surfaces, due to its excellent coagulation strength.

[0317] Furthermore, the moisture-curing hot-melt adhesive of the present invention exhibits an appropriate viscosity at the coating temperature, resulting in excellent coating workability. Furthermore, the moisture-curing silylated polyurethane adhesive of the present invention is formulated to contain substantially no isocyanate groups. Therefore, free monomeric polyisocyanates are not released upon heating, and there is virtually no reaction with moisture to form polyureas. This prevents expansion of the adhesive surface caused by carbon dioxide release and reduces adhesive strength.

[0318] When one or both adherends are made of wood-based materials such as wood, plywood, or wood-based fiberboard, or moisture-permeable materials such as paper, the bond strength decreases over time when using a urethane-based reactive hot-melt adhesive. This tendency is particularly pronounced in high-humidity environments. On the other hand, the moisture-curing hot-melt adhesive of the present invention exhibits no decrease in bond strength over time for adherends made of wood-based or moisture-permeable materials, even when used in high-humidity environments. Therefore, the reactive hot-melt adhesive of the present invention is particularly useful when using wood-based or moisture-permeable materials as adherends.

[0319] [Example]

[0320] The following examples are given to explain the present invention in more detail. However, these examples are for illustration only and should not be interpreted as limiting.

[0321] (Synthesis Example 1: Synthesis of a Hydroxyl-containing Alkoxysilyl-containing Methyl Methacrylate Polymer (a2-1))

[0322] 70 g of methyl methacrylate, 30 g of 2-ethylhexyl methacrylate, 8 g of 3-methacryloyloxypropyltrimethoxysilane, 0.1 g of dichlorotantalum as a metal catalyst, and 40 g of ethyl acetate as an organic solvent were added to a reaction vessel and heated to 80°C under a nitrogen atmosphere while stirring. Subsequently, 0.85 g of mercaptoethanol was added and the temperature was adjusted by heating and / or cooling so that the temperature in the reaction vessel could be maintained at 80°C while reacting for 16 hours. After reacting for 16 hours, the temperature of the reactants was returned to room temperature to terminate the polymerization, thereby obtaining a methyl methacrylate-based polymer (a2-1) containing an alkoxysilyl group and having a hydroxyl group. The number average molecular weight of component (a2-1) measured by gel permeation chromatography was 4,755, and the non-volatile content was 66%.

[0323] (Determination of number average molecular weight)

[0324] The number average molecular weight is measured by gel permeation chromatography (GPC) under the following conditions. Specifically, the object to be measured is measured by GPC under the following measurement conditions, and the molecular weight with the highest frequency converted to standard polyethylene glycol is defined as the number average molecular weight.

[0325] The number average molecular weight can be measured, for example, using HLC-8220 (manufactured by Tosoh Corporation) with polystyrene as a standard substance under the following conditions. The same applies to the measurement of the number average molecular weight in the synthesis examples described below.

[0326] Columns used: G7000HXL × 1, GMHXL × 2, G2000HXL × 1

[0327] Solvent: THF

[0328] Flow rate: 1.0ml / min

[0329] Measurement temperature: 40°C

[0330] (Synthesis Example 2: Synthesis of an Alkoxysilyl-Containing Urethane Prepolymer (Polymer A))

[0331] 100 g of polypropylene glycol (trade name: EDL-S101, a polypropylene glycol ethylene oxide adduct (number average molecular weight 7,060, manufactured by Mitsui Chemicals SKC)) with a number average molecular weight of 7,000 was melt-mixed at 120°C for 1 hour and dehydrated under reduced pressure. 7.3 g of diphenylmethane diisocyanate (MDI) (trade name: Millionate MT, manufactured by Tosoh Corporation) and 0.05 g of an amine catalyst (trade name: U-660M, manufactured by SAN-APRO Corporation) were then added and reacted at 100°C for 3 hours with stirring under a nitrogen atmosphere to obtain a urethane prepolymer (a1-1). Subsequently, 140.7 g (based on solid content) of the hydroxyl-containing, alkoxysilyl-containing methyl methacrylate polymer (a2-1) with a number average molecular weight of 4,755 obtained in Synthesis Example 1 was added and stirred at 100°C for 2 hours. After the reaction was completed, IR spectroscopy confirmed that the absorption of -NCO derived from the isocyanate group disappeared. After the reaction was completed, the solvent was distilled off to obtain a polymer A.

[0332] (IR spectrum measurement)

[0333] The following measuring apparatus was used for the measurement of IR spectrum.

[0334] FT-IR measuring instrument: FT-IR460Plus manufactured by JASCO Corporation

[0335] In addition, the conditions for IR spectrum measurement in the synthesis examples described later are also the same.

[0336] (Synthesis Example 3: Synthesis of Alkoxysilyl-Containing Urethane Prepolymer (Polymer B))

[0337] 100 g of polypropylene glycol with a number average molecular weight of 7,000 (trade name: EDL-S101, polypropylene glycol ethylene oxide adduct (number average molecular weight 7,060, manufactured by Mitsui Chemicals SKC Co., Ltd.)) and 28.3 g of crystalline polyester polyol with a number average molecular weight of 2,000 (crystalline aliphatic polyester polyol composed of sebacic acid and 1,6-hexanediol (number average molecular weight 2,000, melting point (Tg) 65°C, trade name: HS2H-200S, manufactured by Toyokuni Oil Manufacturing Co., Ltd.)) were melt-mixed at 120°C for 1 hour and dehydrated under reduced pressure, and then diphenylmethane diisocyanate (MDI) (trade name: Millionate MT, manufactured by Tosoh Corporation) 10.6 g, and 0.05 g of an amine catalyst (trade name: U-660M, manufactured by SAN-APRO Corporation) were reacted at 100°C for 3 hours while stirring under a nitrogen atmosphere to obtain a urethane prepolymer (a1-2). Subsequently, 160.8 g (solid content conversion) of the methyl methacrylate polymer (a2-1) containing a hydroxyl group and having an alkoxysilyl group and having a number average molecular weight of 4,755 obtained in Synthesis Example 1 was added, and stirred at 100°C for 2 hours. After the reaction was completed, IR spectroscopy was used to confirm that the absorption of -NCO derived from the isocyanate group disappeared. After the reaction was completed, the solvent was distilled off to obtain Polymer B.

[0338] (Synthesis Example 4: Synthesis of Alkoxysilyl-Containing Urethane Prepolymer (Polymer C))

[0339] 100 g of polypropylene glycol with a number average molecular weight of 7,000 (trade name: EDL-S101, polypropylene glycol ethylene oxide adduct (number average molecular weight 7,060, manufactured by Mitsui Chemicals SKC Co., Ltd.)) and 56.0 g of a crystalline polyester polyol with a number average molecular weight of 2,000 (crystalline aliphatic polyester polyol composed of sebacic acid and 1,6-hexanediol (number average molecular weight 2,000, melting point (Tg) 65°C, trade name: HS2H-200S, manufactured by Toyokuni Oil Manufacturing Co., Ltd.)) were melt-mixed at 120°C for 1 hour and dehydrated under reduced pressure, and then diphenylmethane diisocyanate (MDI) (trade name: Millionate MT, manufactured by Tosoh Corporation) 15.8 g, and 0.05 g of an amine catalyst (trade name: U-660M, manufactured by SAN-APRO) were added to the mixture and reacted at 100°C for 3 hours while stirring under a nitrogen atmosphere to obtain a urethane prepolymer (a1-3). Then, 60.7 g (solid content conversion) of the methyl methacrylate polymer (a2-1) containing a hydroxyl group and having an alkoxysilyl group and having a number average molecular weight of 4,755 obtained in Synthesis Example 1 and 7.3 g of N-phenyl-3-aminopropyltrimethoxysilane (a2-2; phenylaminosilane) (trade name: KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and stirred at 100°C for 2 hours. The reaction was completed by confirming the disappearance of the absorption of -NCO derived from the isocyanate group by IR spectroscopy. After the reaction was completed, the solvent was distilled off to obtain Polymer C.

[0340] (Synthesis Example 5: Synthesis of Alkoxysilyl-Containing Urethane Prepolymer (Polymer D))

[0341] 100 g of polypropylene glycol with a number average molecular weight of 7,000 (trade name: EDL-S101, polypropylene glycol ethylene oxide adduct (number average molecular weight 7,060, manufactured by Mitsui Chemicals SKC Co., Ltd.)) and 56.0 g of a crystalline polyester polyol with a number average molecular weight of 2,000 (crystalline aliphatic polyester polyol composed of sebacic acid and 1,6-hexanediol (number average molecular weight 2,000, melting point (Tg) 65°C, trade name: HS2H-200S, manufactured by Toyokuni Oil Manufacturing Co., Ltd.)) were melt-mixed at 120°C for 1 hour and dehydrated under reduced pressure, and then diphenylmethane diisocyanate (MDI) (trade name: Millionate MT, manufactured by Tosoh Corporation) 15.8 g, and 0.05 g of an amine catalyst (trade name: U-660M, manufactured by SAN-APRO Corporation) were added and reacted at 100°C for 3 hours while stirring under a nitrogen atmosphere to obtain a urethane prepolymer (a1-3). Then, 60.7 g (solid content conversion) of the methyl methacrylate polymer (a2-1) containing a hydroxyl group and having a number average molecular weight of 4,755 obtained in Synthesis Example 1, 3.1 g of N-phenyl-3-aminopropyltrimethoxysilane (a2-2) (trade name: KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.), and 2.1 g of dibutylamine were added and stirred at 100°C for 2 hours. The reaction was completed by confirming the disappearance of the absorption of -NCO derived from the isocyanate group by IR spectroscopy. After the reaction was completed, the solvent was distilled off to obtain Polymer D.

[0342] (Synthesis Example 6: Synthesis of Alkoxysilyl-Containing Urethane Prepolymer (Polymer E))

[0343] 100 g of polypropylene glycol (trade name: EDL-S101, a polypropylene glycol ethylene oxide adduct (number average molecular weight 7,060, manufactured by Mitsui Chemicals SKC)) with a number average molecular weight of 7,000 was melt-mixed at 120°C for 1 hour and dehydrated under reduced pressure. 7.3 g of diphenylmethane diisocyanate (MDI) (trade name: Millionate MT, manufactured by Tosoh Corporation) and 0.05 g of an amine catalyst (trade name: U-660M, manufactured by San-Apro Corporation) were then added and reacted at 100°C for 3 hours with stirring under a nitrogen atmosphere to obtain a urethane prepolymer (a1-1). Subsequently, 7.6 g of N-phenyl-3-aminopropyltrimethoxysilane (a2-2; phenylaminosilane) (trade name: KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred at 100°C for 2 hours to obtain a polymer E. After the reaction was completed, IR spectroscopy confirmed that the absorption of -NCO derived from the isocyanate group disappeared.

[0344] (Synthesis Example 7: Synthesis of Alkoxysilyl-Containing Urethane Prepolymer (Polymer F))

[0345] 100.0 g of a crystalline polyester polyol having a number average molecular weight of 2,000 (a crystalline aliphatic polyester polyol composed of sebacic acid and 1,6-hexanediol (number average molecular weight 2,000, melting point (Tg) 65°C, trade name: HS2H-200S, manufactured by Toyokuni Oil Manufacturing Co., Ltd.)) was charged into a reaction vessel, melt-mixed at 120°C for 1 hour and dehydrated under reduced pressure. Then, 25.7 g of diphenylmethane diisocyanate (MDI) (trade name: Millionate MT, manufactured by Tosoh Corporation) and 0.05 g of an amine catalyst (trade name: U-660M, manufactured by SAN-APRO Corporation) were added, and the mixture was reacted at 100°C for 3 hours while stirring under a nitrogen atmosphere to obtain a urethane prepolymer (a1-4). Then, 25.5 g of N-phenyl-3-aminopropyltrimethoxysilane (a2-2; phenylaminosilane) (trade name: KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred at 100°C for 2 hours to obtain Polymer F. Completion of the reaction was confirmed by disappearance of absorption derived from -NCO of the isocyanate group by IR spectroscopy.

[0346] (Synthesis Example 8: Silane Compound)

[0347] First, Silane Compound 2 was synthesized as a silane-based adhesion promoter by reacting two silane compounds with each other. Specifically, 1 mol of 3-glycidoxypropyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) and 1 mol of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed. Then, 1 mol of 3-glycidoxypropyltrimethoxysilane and 1 mol of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane were mixed and heated at 80°C for 3 days to react. This yielded Silane Compound 2, a silane-based adhesion promoter. The molecular weight of Silane Compound 2 was 458.7 g / mol.

[0348] (Synthesis Example 9: Synthesis of Fluorinated Polymer)

[0349] Using polypropylene glycol with a molecular weight of about 2,000 as an initiator, propylene oxide is reacted in the presence of a zinc hexacyanocobaltate-ethylene glycol dimethyl ether complex catalyst to obtain polypropylene glycol. According to the method of Synthesis Example 2 of WO2015-088021, a polyoxyalkylene polymer having an allyl group at the end of the obtained polypropylene glycol is obtained. To this polymer, methyldimethoxysilane as a hydrogenated silyl compound and a platinum vinylsiloxane complex isopropanol solution are added and reacted to obtain a polyoxyalkylene polymer (J) having a methyldimethoxysilyl group at the end. The molecular weight of the obtained polyoxyalkylene polymer having a methyldimethoxysilyl group at the end was determined by GPC. The peak molecular weight was 15,000 and the molecular weight distribution was 1.3. By 1 H-NMR measurement (using NMR400 manufactured by Shimadzu Corporation, measured in CDCl3 solvent) showed that the number of methyldimethoxysilyl groups at the terminal was 1.7 per molecule. Next, using 2.4 g of BF3 diethyl ether complex, 1.6 g of dehydrated methanol, 100 g of polymer (J), and 5 g of toluene, a polyoxyalkylene polymer having a fluorosilyl group at the terminal (hereinafter referred to as "fluorinated polymer") was obtained according to the method of Synthesis Example 4 of WO2015-088021. The obtained fluorinated polymer was measured. 1 H-NMR spectroscopy confirmed that the peak (m, 0.63 ppm) corresponding to the silylmethylene group (-CH2-Si) of the polymer as a raw material disappeared, and a broad peak appeared on the low magnetic field side (0.7 ppm to).

[0350] (Synthesis Example 10: Synthesis of Alkoxysilyl-Containing Methyl Methacrylate Polymer)

[0351] A flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser was charged with 70 parts by mass of methyl methacrylate, 30 parts by mass of 2-ethylhexyl methacrylate, 12 parts by mass of γ-methacryloyloxypropyltrimethoxysilane, 0.1 parts by mass of dichlorotitanocene as a metal catalyst, and 40 parts by mass of ethyl acetate as an organic solvent. The contents were heated to 80°C while nitrogen was introduced into the flask. Subsequently, 8.5 parts by mass of 3-mercaptopropyltrimethoxysilane, which had been thoroughly purged with nitrogen, was added to the stirred flask in one go. The mixture was then heated and cooled for 16 hours, maintaining the temperature of the stirred flask at 80°C. After the reaction was allowed to proceed for 16 hours, the temperature of the reactants was returned to room temperature to terminate the polymerization, yielding an alkoxysilyl-containing methyl methacrylate polymer having two silyl groups per molecule. The monomer residual rate in the ethyl acetate solution of the resulting reaction product was measured using gas chromatography to determine the polymerization rate. As a result, a reaction product with a polymerization yield of 97% was obtained. The solids content of the resulting ethyl acetate solution was determined by heating it at 105°C to 70.5%. Furthermore, the molecular weight of the resulting polymer, as measured by gel permeation chromatography (GPC), was 3800 in weight average molecular weight (Mw), 1500 in number average molecular weight (Mn), 2.4 in dispersion index, and 2.2 (Pa·s) in viscosity at 25°C.

[0352] Table 1 shows the main blending substances in Synthesis Examples 2 to 7.

[0353] [Table 1]

[0354]

[0355] (Examples, Comparative Examples)

[0356] For Examples 1 to 7 and Comparative Examples 1 to 4, component (A) or an alkoxysilyl-containing methyl methacrylate polymer (Synthesis Example 10), component (B), component (C), component (D), component (E), and / or a moisture absorbent were mixed in the blending ratios shown in Table 2 and stirred at 120°C. Finally, degassing was performed under reduced pressure, and a one-component moisture-curing reactive hot-melt adhesive was filled into a metal container for the adhesives of Examples 1 to 7 and Comparative Examples 1 to 4, respectively. The following evaluations were performed on the adhesives of Examples 1 to 7 and Comparative Examples 1 to 4, respectively. The results are shown in Table 2. In Table 2, the unit of the blending amount of each blending substance is "g", and the amount of polymer added in Synthesis Example 10 is the solid content conversion value.

[0357] [Table 2]

[0358]

[0359] Among the materials shown in Table 2, the detailed descriptions of the materials not shown in the synthesis examples are as follows.

[0360] FTR6100 (styrene monomer / aliphatic monomer copolymer, trade name: FTR6100, manufactured by Mitsui Chemicals)

[0361] U-830 (tin catalyst; dioctyltin diversatate, trade name: Neostan U-830, manufactured by Nitto Kasei Co., Ltd.)

[0362] SPUR1050MM (a silylated polyurethane having two trimethoxysilane terminal groups corresponding to silylated polyetherurethane 1 and a polyoxypropylene backbone (number average molecular weight [Mn] 16,400, polydispersity [Mw / Mn] = approximately 1.7, silicon functional group content = 0.122 milliequivalents / polymer gram, viscosity: 35,000 mPa·s / 23°C [ASTM standard D1236], trade name: SPUR+1050MM, manufactured by Momentive)

[0363] KBM3103C (decyltrimethoxysilane, trade name: KBM3103C, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0364] (Evaluation method: 120℃ viscosity)

[0365] The viscosity of the molten state of the one-component moisture-curing reactive hot melt adhesive at 120°C was measured (Pa·s) using a cone-plate viscometer CV-1 (manufactured by Toa Industry Co., Ltd., cone diameter: 14.5 mm, cone angle: 2.0°, rotation speed: 20 rpm).

[0366] (Evaluation method: shear adhesion strength)

[0367] The one-component moisture-curing reactive hot melt adhesive of Example 1 was heated and melted at 120°C and applied to a first aluminum plate (25mm×75mm×2mm, the bonding surface was degreased with acetone) to a thickness of 100μm. Immediately after application, a second aluminum plate (25mm×75mm×2mm, the bonding surface was degreased with acetone) was attached to the first aluminum plate in a sandwich adhesive manner so that the area of the overlapping region became 25mm×25mm from one end, thereby producing a test body. After the test body was cured for a specified time (curing time: 10 minutes after bonding and 1 week after bonding) at a tensile speed of 50mm / min in accordance with JIS K6850, the shear bond strength (N / mm 2Here, the shear strength after curing for 10 minutes after bonding is defined as the "initial strength" (in Table 2, the shear strength after curing for 10 minutes (N / mm 2 )(Al×Al))”, the shear strength after one week was defined as the “final strength (Table 2, shear strength after one week of curing (N / mm 2 )(Al×Al))” The same evaluation was performed on the one-component moisture-curing reactive hot-melt adhesives of other examples and comparative examples.

[0368] (Evaluation method: bonding time)

[0369] The one-component, moisture-curing, reactive hot-melt adhesive from Example 1 was melted at 120°C and applied to a kraft liner corrugated cardboard (250 mm × 250 mm × 7 mm) at a thickness of 50 μm. A test piece (kraft liner corrugated cardboard (25 mm × 50 mm × 7 mm)) was then bonded to the cardboard with virtually no gaps at specified intervals (every 3 seconds until 1 minute, and every 15 seconds thereafter). Each test piece was then allowed to stand for 10 minutes in an environment of 23°C and 50% RH. The test piece was then manually peeled off, and the time required for no defects to form at the bonded area was determined as the bonding time (seconds). The one-component, moisture-curing, reactive hot-melt adhesives from the other examples and comparative examples were evaluated in the same manner.

[0370] As can be seen from Table 2, it can be confirmed that the adhesives of the examples all exhibited a good lamination time of 2 minutes or longer and also exhibited good coagulation strength.

[0371] On the other hand, referring to Table 2, it can be seen that the adhesives of the comparative examples all exhibited extremely short bonding times and poor coagulation strength.

[0372] While the embodiments and examples of the present invention have been described above, the embodiments and examples described above are not intended to limit the scope of the invention claimed. Furthermore, it should be noted that the combination of features described in the embodiments and examples is not necessarily necessary to solve the problems of the invention, and various modifications are possible without departing from the technical spirit of the invention.

Claims

1. A moisture-curable hot-melt adhesive comprising an alkoxysilyl-containing urethane prepolymer (A), This (A) is a compound obtained by reacting a diisocyanate (i), a polyether polyol (ii-1), and a compound (a2) containing an alkoxysilyl group and an active hydrogen group, and is a polymer that is solid at room temperature, wherein the (a2) contains a methyl methacrylate-based polymer (a2-1) having an alkoxysilyl group and a hydroxyl group.

2. The moisture-curable hot-melt adhesive according to claim 1, wherein the (A) is a compound obtained by reacting the diisocyanate (i), the polyether polyol (ii-1), the compound (a2) containing an alkoxysilyl group and an active hydrogen group, and an alkoxysilane (a2-2) having an active hydrogen group.

3. The moisture-curable hot-melt adhesive according to claim 1, wherein the (A) is a compound obtained by reacting the diisocyanate (i), the polyether polyol (ii-1), the compound (a2) containing an alkoxysilyl group and an active hydrogen group, and a polyester polyol (ii-2) and / or a polycarbonate polyol (ii-3). 4 . The moisture-curable hot-melt adhesive according to claim 3 , wherein the polyester polyol (ii-2) is a crystalline aliphatic polyester polyol. 5 . The moisture-curable hot-melt adhesive according to claim 3 , wherein the polycarbonate polyol (ii-3) is a crystalline aliphatic polycarbonate polyol. 6 . The moisture-curable hot-melt adhesive according to claim 1 , further comprising a silane-based tackifier (B).

7. The moisture-curable hot-melt adhesive according to claim 1, further comprising at least one of a terpene-phenol resin and an aromatic petroleum resin as a modifying resin (C). 8 . The moisture-curable hot-melt adhesive according to claim 1 , further comprising a cross-linking catalyst (D).

9. A product comprising the moisture-curable hot-melt adhesive according to claim 1.

Images