Moisture-curing hot melt adhesive

Abstract

Provided is a moisture-curable hot-melt adhesive capable of combining satisfactory initial bonding strength with a sufficiently long working time. The moisture-curable hot-melt adhesive includes an alkoxysilyl-group-containing urethane prepolymer (A) which is represented by general formula (a). general formula (a) In (a): Y represents a residue in which –O–C(=O) –NH–A–NCO has been removed from an isocyanate group terminal urethane prepolymer (a1), which is a reactant between a polyisocyanate (i) and a polyol (ii); A represents a residue after two isocyanate groups have been removed from a divalent diisocyanate; W represents a residue in which an active hydrogen group has been removed from a compound (a2), which includes an alkoxysilyl group and an active hydrogen group; X represents O, S or NR1; and R1 is a linear or branched monovalent hydrocarbon group having a hydrogen atom or 1-20 carbon atoms.

Description

[Technical Field]

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

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

[0003] The solidification time of the starting components of the PU hot melt adhesive without mutual reaction can be adjusted within a range of seconds to minutes by changing the blending ratio of crystalline or amorphous components at room temperature. In this regard, it is known that the crystalline structure of the PU hot melt adhesive reduces the melt viscosity of the adhesive, improving its applicability, and also provides good low-temperature elasticity due to its short solidification time after application and its low glass transition temperature (see, for example, Patent Documents 2 and 3).

[0004] The curing process, which involves crosslinking between the components of reactive PU hot melt adhesives, proceeds over several days through the reaction of isocyanate groups with moisture, forming a thermoset polyurea. After this, the PU hot melt adhesive no longer melts or dissolves in solvents. This allows the cured adhesive to exhibit good heat resistance and good resistance to chemicals, such as plasticizers, solvents, oils, and fuels.

[0005] However, due to the preparation method of these adhesives, high concentrations of free monomeric polyisocyanates, such as 4,4'-diisocyanatodiphenylmethane (4,4'-MDI), 2,4-diisocyanatotoluene, or 2,6-diisocyanatotoluene (TDI), remain in the adhesives described above. Since these monomeric polyisocyanates exhibit vapor pressures at the adhesive application temperature (approximately 100°C to approximately 180°C) that cause the monomeric components to be released in a gaseous state into the surrounding environment, it is necessary to install equipment such as a specified exhaust system.

[0006] Furthermore, the above-mentioned adhesive reacts with moisture to form polyurea. When polyurea is formed, carbon dioxide is released from the adhesive. This causes foaming in the adhesive bonding area. This results in expansion of the surfaces of the bonded components and a decrease in adhesive strength.

[0007] Furthermore, reactive hot melt adhesives require a balance between heat stability (no increase in viscosity and no hardening) and room temperature hardening. However, reactive PU hot melt adhesives have the drawback of insufficient heat stability. Reactive PU hot melt adhesives must be heated and melted before application, and during this process, the terminal isocyanate groups react with the urethane or urea bonds in the molecular chain to form allophanate or biuret bonds, forming a three-dimensional crosslinked structure that can increase the viscosity of the composition or cause gelation.

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

[0009] However, the adhesive composition described in Patent Document 4 is a pressure-sensitive adhesive (pressure-sensitive adhesive), and since tack remains even after curing, stickiness may be a problem depending on the application. In addition, the composition described in Patent Document 5 may not have sufficient build-up strength, and with the moisture-curable hot melt adhesive composition described in Patent Document 6, it is difficult to ensure both a sufficient bonding time and sufficient build-up strength. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 4-227714 [Patent Document 2] Japanese Patent Application Publication No. 2-088686 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-205764 [Patent Document 4] Patent No. 6027146 [Patent Document 5] Patent No. 5738849 [Patent Document 6] Patent No. 5254804 Summary of the Invention [Problem to be solved by the invention]

[0011] In other words, there is a need for a hot melt adhesive that has a higher rise strength and a sufficiently long bondable time than the conventional techniques such as those in the above-mentioned patent documents. Therefore, an object of the present invention is to provide a moisture-curable hot melt adhesive that can achieve both good rise strength and a sufficiently long bondable time. [Means for solving the problem]

[0012] In order to achieve the above object, the present invention provides a moisture-curable hot melt adhesive containing an alkoxysilyl group-containing urethane prepolymer (A) represented by the following general formula (a):

[0013] [ka]

[0014] 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) that is a reaction product 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 a methyl methacrylate polymer (a2-1) that is solid at room temperature and has an alkoxysilyl group and a hydroxyl group, and X represents O, S, or NR 1 where R 1 represents a hydrogen atom or a linear or branched monovalent hydrocarbon radical having 1 to 20 C atoms, which may optionally contain cyclic moieties, or represents a radical of the general formula (b).

[0015] [ka]

[0016] R 2 and R 3 are, independently of each other, a hydrogen atom or -R 5 , -COOR 5 and —CN, and further R 4 is a hydrogen atom or -CH2-COOR 5 , -COOR 5 , -CONHR 5 , -CON(R 5 )2, -CN, -NO2, -PO(OR 5 )2, -SO2R 5 , and -SO2OR 5 R represents a group selected from the group consisting of 5represents a hydrocarbon group having 1 to 20 C atoms, which may optionally contain one or more heteroatoms, and n is a number equal to or greater than 1. [Effects of the Invention]

[0017] According to the moisture-curable hot melt adhesive of the present invention, it is possible to provide a moisture-curable hot melt adhesive that can achieve both good rising strength and a sufficiently long bonding time. DETAILED DESCRIPTION OF THE INVENTION

[0018] <Definitions and meanings of values and terms> The definitions and meanings of the values and terms used in this specification are as follows:

[0019] "Room temperature" or "normal temperature" refers to a temperature of 23°C.

[0020] The term "solid at room temperature" means that the substance (e.g., a given composition) is crystalline, partially crystalline, and / or glassy amorphous and has a softening point (as measured by ring and ball) or melting point greater than 23°C. The melting point is the maximum of the curve measured during a heating operation, e.g., by dynamic differential calorimetry (differential scanning calorimetry [DSC]), at which the material transitions from a solid to a liquid state. Thus, the term "liquid at room temperature" means that the substance has a softening point or melting point of 23°C or less.

[0021] The "bonding time" is the time from when the adhesive is applied to an adherend until it can be bonded to another adherend. The "bonding time" can be measured in accordance with the Japanese Adhesive Industry Standard JAI7-1991.

[0022] The "setting time" is the time it takes for the hot melt adhesive that has been applied to the adherend to cool and solidify and exhibit initial adhesive strength.

[0023] <Overview of moisture-curing hot melt adhesives> Hot melt adhesives are required to have a sufficiently high bond strength after application to an adherend (in other words, a practically short time until they solidify and exhibit sufficient adhesive strength), and also to have a sufficiently long bondable time, i.e., a sufficient time until the hot melt adhesive can no longer properly bond another adherend to the adherend to which the hot melt adhesive has been applied. The bond strength is the strength exhibited by the hot melt adhesive upon solidification, and solidification refers to the process by which the hot melt adhesive is melted by heating and then cooled to a solid state. After solidification, reactive hot melt adhesives undergo crosslinking reactions due to moisture curing, triggered by silyl groups and other components in the adhesive, which then progresses to hardening.

[0024] The inventors have investigated various compounds and compositions that make up hot melt adhesives and found that by incorporating a crystalline structure and a partial amorphous molecular region, and by selecting specific ingredients, it is possible to achieve both sufficient build-up strength and a sufficiently long bondable time. Furthermore, they have found that incorporating reactive groups into the prepolymers that make up the adhesive allows the crosslinking reaction to proceed primarily after the adhesive has solidified, thereby sufficiently improving the adhesive's final strength. In other words, they have found that incorporating a crystalline compound into the materials that make up the hot melt adhesive allows the bondable time to be adjusted, that incorporating a partial region corresponding to an amorphous molecule, such as an ether bond in a polyether, ensures flexibility, and that incorporating a prepolymer with a reactive group at its end allows the crosslinking reaction, which primarily begins after application of the adhesive, to proceed over time, thereby sufficiently improving the final strength.

[0025] 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):

[0026] [ka]

[0027] 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) that is a reaction product of a diisocyanate (i) and a polyol (ii) (hereinafter referred to as "residue Y"), 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 a methyl methacrylate polymer (a2-1) that has an alkoxysilyl group and a hydroxyl group and is solid at room temperature, and X represents O, S, or NR 1 where R 1 represents a hydrogen atom or a linear or branched monovalent hydrocarbon radical having 1 to 20 C atoms, which may optionally contain cyclic moieties, or represents a radical of the general formula (b).

[0028] [ka]

[0029] R 2 and R 3 are, independently of each other, a hydrogen atom or -R 5 , -COOR 5 and —CN, and further R 4 is a hydrogen atom or -CH2-COOR 5 , -COOR 5 , -CONHR 5 , -CON(R 5 )2, -CN, -NO2, -PO(OR 5 )2, -SO2R 5 , and -SO2OR 5 R represents a group selected from the group consisting of 5represents a hydrocarbon group having 1 to 20 C atoms, which may optionally contain one or more heteroatoms, and n is a number equal to or greater than 1.

[0030] The moisture-curable hot melt adhesive of the present invention comprises an alkoxysilyl group-containing urethane prepolymer (A) (hereinafter referred to as component (A)) of general formula (a). Component (A) is generally obtained by reacting an isocyanate group-terminated urethane prepolymer (a1) (hereinafter referred to as component (a1)) represented by formula (I) with a compound (a2) (hereinafter referred to as component (a2)) containing an alkoxysilyl group and an active hydrogen group represented by formula (II).

[0031] [ka]

[0032] In formula (I), A, Y, and n are the same as above.

[0033] [ka]

[0034] In formula (II), X and W are the same as above.

[0035] The method for preparing component (a1) is not particularly limited. For example, component (a1) may be prepared as 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 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 portion of component (ii-1). Furthermore, component (ii-2) may be crystalline aliphatic polyester polyol (ii-2-1) (hereinafter referred to as component (ii-2-1)).

[0036] 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 its terminal. Component (a2) may further contain, in addition to component (a2-1) or in place of a portion of component (a2-1), an alkoxysilane (a2-2) (hereinafter referred to as component (a2-2)) having an active hydrogen group.

[0037] (Other methods for preparing component (A)) 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") can be obtained by reacting a compound (a2) containing an alkoxysilyl group and an active hydrogen group with a diisocyanate (formula: OCN-A-NCO).

[0038] [ka]

[0039] Y" is a residue obtained by removing a hydroxyl group from polyol (ii) (hereinafter referred to as Y" residue), and has the same structure as the residue obtained by removing -OC(=O)-NH-A-NCO from isocyanate-terminated urethane prepolymer (a1), which is the reaction product of diisocyanate (i) and polyol (ii) described above (Y residue).

[0040] [ka]

[0041] where A, X, and W are the same as above.

[0042] In addition to the above components, the moisture-curable hot melt adhesive of the present invention may further contain a silane-based adhesion promoter (B) (hereinafter referred to as component (B)), a modified resin (C) (hereinafter referred to as component (C)), a catalyst (crosslinking catalyst) (D) (hereinafter referred to as component (D)), which is at least one selected from the group consisting of amine compounds, divalent tin compounds, and fluorinated polymers, and / or a silylated polymer (E) (hereinafter referred to as component (E)).

[0043] Furthermore, the hot melt adhesive according to the present invention may be configured as a photocurable adhesive.

[0044] <Moisture-curing hot melt adhesive details> The moisture-curable hot melt adhesive according to the present invention comprises an alkoxysilyl group-containing urethane prepolymer (A) represented by general formula (a), and there are no particular limitations on the method for preparing component (A).

[0045] For example, a moisture-curable hot melt adhesive can be prepared by reacting component (i) with component (ii) to prepare component (a1), and then reacting the resulting component (a1) with component (a2) to prepare component (A). Alternatively, 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). Component (A) may be prepared by reacting component (a2) with component (i) or component (ii), and then further reacting component (ii) or component (i). Alternatively, component (i), component (ii), and component (a2) may be simultaneously reacted.

[0046] The hot melt adhesive according to the present invention is solid at room temperature and is applied to an adherend in a heated and melted state. Each component will be described in detail below. In the following description, the moisture-curing hot melt adhesive according to the present invention may be referred to as a "reactive hot melt adhesive" or a "one-component moisture-curing reactive hot melt adhesive."

[0047] <(A) Alkoxysilyl Group-Containing Urethane Prepolymer> The alkoxysilyl group-containing urethane prepolymer (A) according to the present invention is a polymer having alkoxysilyl groups represented by general formula (a) and containing urethane bonds. The alkoxysilyl group-containing urethane prepolymer (A) is a polymer essentially comprising a polyether skeleton (a skeleton formed by removing hydroxyl groups from a polyether polyol), and is a polymer in which a polymer containing a polyether skeleton is linked via a urethane bond to a skeleton of an alkoxysilyl group-containing acrylic polymer (a skeleton formed by removing hydroxyl groups from a methyl methacrylate polymer having alkoxysilyl groups and hydroxyl groups). The urethane bond is formed by a linking group represented by the following general formula (V), which is generated by the reaction of the terminal hydroxyl groups of the polyether polyol and the alkoxysilyl group-containing acrylic polymer with a linking agent (a diisocyanate compound). Linking these two polymers together produces a polymer with both toughness and flexibility.

[0048] -OC(=O)NH-A-NHC(=O)O- (V)

[0049] Note that A is the same as above.

[0050] From the viewpoint of increasing the rising strength of the hot melt adhesive according to the present invention, it is preferable that component (A) is solid at room temperature.

[0051] <(a1) Isocyanate Group-Terminated Urethane Prepolymer> The isocyanate-terminated urethane prepolymer (a1) according to 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)).

[0052] For example, the isocyanate-terminated urethane prepolymer (a1) according to the present invention can be obtained by reacting a diisocyanate with a polyether polyol in such a state 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 group / hydroxyl group molar ratio) exceeds 1, i.e., the isocyanate groups are in excess relative to the hydroxyl groups. Here, the isocyanate group / hydroxyl group molar ratio is preferably 1.5 or more, more preferably 1.8 or more, even more preferably 1.9 or more, and preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.1 or less. When the isocyanate group / hydroxyl group molar ratio is within the range, good coatability can be obtained.

[0053] In addition, (i) isocyanate group-terminated urethane prepolymer can also be obtained by modifying a polyether polyol or a portion thereof using a diisocyanate (e.g., 1,6-diisocyanatohexane (HDI), 2,4-diisocyanatotoluene (TDI), 2,6-diisocyanatotoluene (TDI), 2,4'-diisocyanatodiphenylmethane (MDI), 4,4'-diisocyanatodiphenylmethane (MDI)) having an isocyanate group in an insufficient molar ratio relative to the hydroxyl groups of the polyether polyol, and after completion of the reaction, reacting an excess of diisocyanate with a polyol having urethane groups.

[0054] The polyether polyol and the diisocyanate may also be reacted in the presence of up to 5% by weight of, for example, a trimer of an aliphatic diisocyanate (such as hexamethylene diisocyanate), or this type of trimer may be added after the prepolymerization reaction is complete.

[0055] [Polyisocyanate] The polyisocyanate according to the present invention is not particularly limited, but examples thereof include diisocyanates.

[0056] (i) Diisocyanate (i) The diisocyanate is not particularly limited, but examples thereof include compounds represented by the following formula (c):

[0057] OCN-A-NCO formula (c)

[0058] In formula (c), A is a residue obtained after removing two isocyanate groups from a divalent diisocyanate, and represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon group having 3 to 20 carbon atoms and containing an alicyclic structure, or a hydrocarbon group having 6 to 20 carbon atoms and containing an aromatic ring.

[0059] Specific examples include aromatic diisocyanates such as phenylene diisocyanate, tolylene 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 isocyanate. Among these, from the viewpoint of use in hot melt adhesives that are used in a melted state, it is preferable to use diphenylmethane diisocyanate, which has a low vapor pressure when heated.

[0060] [(ii) Polyol] Examples of polyols 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.

[0061] The polyol component (ii) contains a polyether polyol (ii-1) as an essential component of the present invention. The component (ii) may further contain a polyester polyol (ii-2) and / or a polycarbonate polyol (ii-3). The component (ii-2) may be a crystalline aliphatic polyester polyol (ii-2-1).

[0062] When component (ii) further comprises polyester polyol (ii-2) and / or polycarbonate polyol (ii-3), the isocyanate-terminated urethane prepolymer (a1) according to the present invention is obtained by reacting a diisocyanate with a polyol such that the 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) exceeds 1, i.e., the isocyanate groups are in excess relative to the hydroxyl groups, so as to form a diisocyanate bond between component (ii) and (ii-2) and / or (ii-3). Here, the isocyanate group / hydroxyl group molar ratio is preferably 1.2 or greater, more preferably 1.3 or greater, and even more preferably 1.4 or greater, from the viewpoint of achieving good coatability. Furthermore, from the viewpoint of achieving good curability, it is preferably 1.9 or less, more preferably 1.7 or less, and even more preferably 1.6 or less.

[0063] ((ii-1) Polyether polyol) Examples of polyether polyols include polypropylene glycol (PPG), polyethylene glycol (PEG), polytetramethylene glycol (PTMG), etc. Although not limited to these polyols, the number average molecular weight is preferably 500 or more, more preferably 1,000 or more, and even more preferably 2,000 or more, and is preferably 30,000 or less, more preferably 20,000 or less, and even more preferably 15,000 or less. In addition, the polyether polyol is preferably a diol.

[0064] The polyether polyol may also be a compound obtained by copolymerizing two or more polyether polyols, such as polyoxyethylene-oxypropylene block copolymer diol. Such diols are preferred because they have primary hydroxyl groups as terminal groups and are highly reactive with isocyanate groups. The polyoxyethylene-oxypropylene block copolymer diol preferably has 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.

[0065] (ii-2) Polyester polyol (ii) The polyester polyol used as the polyol component (hereinafter, sometimes simply referred to as "polyester polyol") refers to a polyester having more than one OH group (preferably, two terminal OH groups).

[0066] The moisture-curable hot melt adhesive of the present invention contains, in its (ii) polyol component, at least one polyester polyol that has a functionality of at least 2 and is solid (preferably an at least partially crystalline solid) at room temperature.

[0067] Furthermore, the moisture-curable hot melt adhesive may contain, in the (ii) polyol component, one or more polyester polyols having a functionality of at least 2 and being at least partially crystalline, one or more aromatic polyester polyols having a functionality of at least 2, alicyclic polyester polyols, one or more polyester polyols having a functionality of at least 2 and being liquid at room temperature, and / or one or more polyether polyols having a functionality of at least 2.

[0068] Here, the meaning of "at least partially crystalline" will be explained. "At least partially crystalline" polyester polyol means that the polyester polyol is not completely crystalline but contains a certain amorphous portion, either partially or additionally. Such polyester polyols have a crystalline melting point (Tm) and a glass transition temperature (hereinafter, sometimes referred to as "Tg"). The melting point indicates the temperature at which the crystalline portion melts. The melting point can be determined as a major endothermic peak (crystalline melting peak) by differential thermal analysis, for example, DSC measurement. According to DSC measurement (heating and cooling rate in the second heating step is 10 K / min), the melting point of at least partially crystalline polyester polyols is about 35°C to about 120°C. The glass transition temperature of at least partially crystalline polyester polyols is generally, for example, significantly lower than room temperature. Suitable partially crystalline polyester polyols (hereinafter, referred to as "crystalline aliphatic polyester polyols") are well known to those skilled in the art. The polyester polyol may also be a polyester polyol linked with a diisocyanate.

[0069] ((ii-2-1) Crystalline Aliphatic Polyester Polyol) (ii-2-1) Examples of crystalline aliphatic polyester polyols include compounds obtained by reacting a compound having two or more hydroxyl groups with a polybasic acid. Also usable are polycaprolactone derivatives based on bifunctional starter molecules, such as 1,6-hexanediol.

[0070] Specifically, examples of compounds having two or more hydroxyl groups (preferably two to three, more preferably two) include linear aliphatic diols having 2 to 16 carbon atoms, such as ethylene glycol, 1,3-propanediol, 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 glycerin. Among these, from the viewpoint of enhancing crystallinity, linear aliphatic diols having 4 to 14 carbon atoms are preferred, and 6 to 12 carbon atoms are more preferred. These compounds can be used alone or in combination of two or more.

[0071] Examples of polybasic acids that can be used include straight-chain 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, from the viewpoint of enhancing crystallinity, the straight-chain aliphatic dicarboxylic acid preferably has 6 to 14 carbon atoms, and more preferably 8 to 12. These polybasic acids can be used alone or in combination of two or more.

[0072] Specifically, the crystalline aliphatic polyester polyol is preferably a long-chain aliphatic polyester polyol represented by the following general formula (VI).

[0073] [ka]

[0074] In general formula (VI), R 6 and R 7 each independently represents a linear 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, and n is 3 to 40.

[0075] Here, R in general formula (VI) 6 Examples of R include linear alkylene groups having an even number of carbon atoms. 6 and R 7 The total number of carbon atoms in R and R can be appropriately selected within the range of 12 or more. 7 is preferably a linear alkylene group having an even number of carbon atoms of 4 or more.

[0076] In addition, R in general formula (VI) 7 is R 6 and independently include a linear alkylene group having an even number of carbon atoms, and R 6 and R 7 The total number of carbon atoms in R and R can be appropriately selected within a range of 12 or more. 7 is preferably a linear alkylene group having an even number of carbon atoms of 10 or more.

[0077] R 6 and R 7 However, by using a long-chain aliphatic polyester polyol, which is a linear alkylene group having the number of carbon atoms within the above range, the crystallinity of the resulting urethane prepolymer can be increased, and a moisture-curing hot melt adhesive with excellent initial adhesive strength and normal adhesive strength can be obtained.

[0078] Furthermore, n in general formula (VI) is 3 to 40, preferably in the range of 9 to 25, and more preferably in the range of 9 to 15. By using a long-chain aliphatic polyester polyol having n within this range, it is possible to obtain a moisture-curable hot melt adhesive that has an appropriate melt viscosity and excellent coating workability.

[0079] Specific examples of the crystalline aliphatic polyester polyol include polyhexamethylene adipate, polyhexamethylene sebacate, polyhexamethylene dodecanate, and polydodecamethylene decanate, with polyhexamethylene sebacate, polyhexamethylene dodecanate, and polydodecamethylene decanate being preferred.

[0080] Here, in order to shorten the time required for sufficient initial strength to be achieved by crystallization of the melt 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. As a result, when adherends are bonded together using the moisture-curable hot melt adhesive of the present invention, the initial strength of the adhesive is sufficient, and it is not necessary to fix one adherend to the other until the adherends no longer slip relative to each other, or only a short period of fixation is sufficient. This is particularly advantageous for vertical bonding, such as bonding windshields or windows of automobiles or public transportation. Furthermore, because the adhesive has high resistance to substrate repulsion (peel-off force) and can be fixed in a short time, it can be used for decorative fixtures obtained by bonding substrates such as plywood, MDF (medium density fiberboard), and particle board to decorative sheets or films, decorative paper, veneer, metal foil, etc., which have decorative colors or patterns on their surfaces.

[0081] The crystalline aliphatic polyester polyol preferably has a number average molecular weight of 1,500 or more, more preferably 2,500 or more, and even more preferably 3,500 or more, and 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 to 200,000. The melting point of the crystalline aliphatic polyester polyol is preferably 35°C or more, more preferably 45°C or more, and even more preferably 55°C or more, and preferably 120°C or less, more preferably 100°C or less, and even more preferably 80°C or less.

[0082] (aromatic polyester polyol) 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.

[0083] Examples of aromatic polycarboxylic acids that can be used include phthalic acid (for example, orthophthalic acid and phthalic anhydride), isophthalic acid, and terephthalic acid. These aromatic polycarboxylic acids can be used alone or in combination of two or more.

[0084] 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, of the total amount of the polybasic acids.

[0085] Other polybasic acids include, for example, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, and 1,12-dodecanedicarboxylic acid. These polybasic acids can be used alone or in combination of two or more. Among these polybasic acids, adipic acid and sebacic acid are preferred.

[0086] Examples of low-molecular-weight aliphatic polyols 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.

[0087] Further, 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-diethylpropanediol, 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.

[0088] Further, examples of low-molecular-weight aliphatic polyols include low-molecular-weight aliphatic polyols having an ether bond, such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol, among which diethylene glycol is preferred. Furthermore, examples of aliphatic polyols that can be used include aromatic polyols obtained by subjecting bisphenol A, bisphenol F, or the like to a ring-opening addition reaction with ethylene oxide, propylene oxide, γ-butyrolactone, ε-caprolactone, or the like, among which aromatic polyols obtained by subjecting bisphenol A, ethylene oxide, or the like to a ring-opening addition reaction are preferred.

[0089] These low-molecular-weight aliphatic polyols can be used alone or in combination of two or more. Among these, neopentyl glycol and diethylene glycol are preferred from the viewpoint of enhancing amorphousness.

[0090] 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.

[0091] Examples of aromatic polyester polyols include aromatic polyester polyols having a number average molecular weight of 2,000 or more and 5,000 or less and a glass transition temperature of 30°C or higher (hereinafter referred to as "aromatic polyester polyols that are solid at room temperature"), and aromatic polyester polyols having a number average molecular weight of 400 or more and 3,500 or less and a glass transition temperature of 20°C or lower (hereinafter referred to as "aromatic polyester polyols that are liquid at room temperature").

[0092] (Aromatic polyester polyol that is solid at room temperature) Aromatic polyester polyols that are solid at room temperature can be produced, for example, by a method in which an aromatic polycarboxylic acid and a low-molecular-weight aliphatic polyol are subjected to a condensation reaction.

[0093] As the aromatic polyester polyol that is solid at room temperature, it is preferable to use an aromatic polyester polyol obtained by appropriately combining ethylene glycol or neopentyl glycol as a low-molecular-weight aliphatic polyol and isophthalic acid or terephthalic acid as an aromatic polycarboxylic acid so that the glass transition temperature is 30°C or higher, and then subjecting them to a condensation reaction by a known method.

[0094] The aromatic polyester polyol that is solid at room temperature is a compound that has a glass transition temperature of 30° C. or higher, and more preferably has a glass transition temperature in the range of 30° C. to 70° C. By using an aromatic polyester polyol that is solid at room temperature and has a glass transition temperature within this range, it is possible to obtain a moisture-curable hot melt adhesive that can further improve adhesion to aromatic resins such as polyethylene terephthalate, impart toughness to improve the initial strength and final strength, and exhibit excellent adhesive strength.

[0095] (aromatic polyester polyol that is liquid at room temperature) Examples of aromatic polyester polyols that are liquid at room temperature include aromatic polyester polyols obtained by reacting a low-molecular-weight aliphatic polyol having an ether bond, a branched-chain aliphatic diol, or the like with an aromatic polycarboxylic acid.

[0096] The aromatic polyester polyol that is liquid at room temperature has a glass transition temperature of 20° C. or lower. Furthermore, the aromatic polyester polyol that is liquid at room temperature preferably has a glass transition temperature within the range of −30° C. or higher and 20° C. or lower. If the glass transition temperature is within this range, a moisture-curable hot melt adhesive that can exhibit even better normal adhesive strength can be obtained.

[0097] (alicyclic polyester polyol) The alicyclic polyester polyol can be produced by a known reaction method using, for example, an alicyclic polyol and an aliphatic polycarboxylic acid (or an acid derivative thereof), or using an aliphatic polyol and an alicyclic polycarboxylic acid (or an acid derivative thereof). Note that the production method is not particularly limited.

[0098] Examples of alicyclic polyols that can be used include cyclopentanediol, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, and adducts of these polyols with alkylene oxides such as ethylene oxide (EO) and propylene oxide (PO). These can be used alone or in combination of two or more.

[0099] Examples of aliphatic polyols 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.

[0100] Examples of alicyclic polycarboxylic acids include cyclohexanedicarboxylic acid and cyclopentanedicarboxylic acid, and among these, cyclohexane diadipate (CHDA) is preferred.

[0101] 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 can be used alone or in combination of two or more.

[0102] The alicyclic polycarboxylic acid and the aliphatic polycarboxylic acid may be used in the form of a corresponding acid derivative such as a lower alkyl ester derivative such as a methyl ester, an acid anhydride, or an acid halide.

[0103] The number average molecular weight (Mn) of the alicyclic polyester polyol is preferably at least 500, more preferably at least 700, and preferably at most 5,000, more preferably at most 3,000, and even more preferably at most 2,000. When the Mn of the alicyclic polyester polyol is within this range, the moisture-curable polyurethane hot melt adhesive has an appropriate melt viscosity, is excellent in coating workability (viscosity suitability) and adhesive strength, and can prevent peeling of the surface member at complexly shaped portions of the substrate after bonding the substrate and the surface member (sheet, film, metal foil, paper, etc.).

[0104] (Aliphatic polyester polyol that is liquid at room temperature) Examples of the aliphatic polyester polyol that is liquid at room temperature include aliphatic polyester polyols that have a number average molecular weight of 4,000 or more and 7,000 or less and that have a branched aliphatic group and are liquid at room temperature.

[0105] The aliphatic polyester polyol that is liquid at room temperature must have a number-average molecular weight in the range of 4,000 to 7,000 in order to maintain both good wettability and high initial adhesive strength in the resulting adhesive in a low-temperature atmosphere. If the number-average molecular weight of the aliphatic polyester polyol that is liquid at room temperature is less than 4,000, the resulting adhesive may have reduced wettability to substrates in a low-temperature atmosphere and a significant decrease in normal adhesive strength. On the other hand, if the number-average molecular weight exceeds 7,000, the crosslink density of the cured product of the resulting adhesive may be increased, resulting in a decrease in hot water resistant adhesive strength.

[0106] Furthermore, it is essential that the aliphatic polyester polyol, which is liquid at room temperature, contains a branched aliphatic group in order to improve the normal adhesive strength to poorly adhesive substrates.

[0107] Examples of branched chain aliphatic groups include branched chain aliphatic diol groups such as 2,2-dimethyl-1,3-propylene, 2-methyl-1,3-propylene, 1,2-diethyl-1,3-propylene, 3,2-diethyl-1,3-propylene, 3-methyl-1,5-pentane, 2-ethyl-2-butyl-propylene, 2-methyl-1,8-octane, and 2,4-diethyl-1,5-pentane. Among these, 2,2-dimethyl-1,3-propylene and 3-methyl-1,5-pentane are preferred, with 2,2-dimethyl-1,3-propylene being more preferred.

[0108] Aliphatic polyester polyols that are liquid at room temperature can be produced by a method of condensing a branched-chain aliphatic diol with a polycarboxylic acid, or a method of ring-opening polymerization of caprolactone, γ-butyrolactone, or the like using a branched-chain aliphatic diol as an initiator. Among these, it is more preferable to use an aliphatic polyester polyol obtained by reacting neopentyl glycol or 3-methyl-1,5-pentanediol (of which 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, from the viewpoint of obtaining a moisture-curable polyurethane hot-melt adhesive that has good wettability in a low-temperature environment.

[0109] When producing an aliphatic polyester polyol that is liquid at room temperature, a low molecular weight aliphatic polyol or aliphatic polycarboxylic acid other than the compounds mentioned above can be used in combination, if necessary.

[0110] As other low molecular weight aliphatic polyols, other aliphatic polyols can be used, etc. Among these, it is preferable to use a linear aliphatic diol having 2 to 12 carbon atoms.

[0111] Examples of aliphatic polycarboxylic acids that can be used in combination include adipic acid, sebacic acid, azelaic acid, decamethylenedicarboxylic acid, etc. Among these, it is preferable to use a linear aliphatic dicarboxylic acid having 4 to 10 carbon atoms.

[0112] ((ii-3) Polycarbonate polyol) In the present invention, the (ii) polyol component may contain a polycarbonate polyol. The use of a polycarbonate polyol can improve the hydrolysis resistance and moisture-resistant adhesion of the moisture-curable hot melt adhesive according to the present invention.

[0113] As the polycarbonate polyol, for example, a compound obtained by reacting a carbonate ester and / or phosgene with a diol can be used.

[0114] Examples of carbonate esters that can be used include dimethyl carbonate, diphenyl carbonate, etc. These compounds can be used alone or in combination of two or more.

[0115] Examples of diols that can be used 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; 1,4-cyclohexanedimethanol, and bisphenol A. These compounds can be used alone or in combination of two or more.

[0116] ((ii-3-1) Crystalline Aliphatic Polycarbonate Polyol) Here, a polycarbonate polyol having only one kind of linear aliphatic diol is solid at room temperature and has crystallinity. In the present invention, it is preferable to use a polycarbonate polyol having only 1,6-hexanediol.

[0117] (Polycarbonate polyol that is liquid at room temperature) Examples of polycarbonate polyols obtained by copolymerizing at least two types of diols include copolymerized polycarbonate diols in which the glycol component is composed of 3-methyl-1,5-pentanediol and 1,6-hexanediol, 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 that are liquid at room temperature can improve the flexibility of the cured coating of the moisture-curable hot melt adhesive according to the present invention.

[0118] The number average molecular weight of the polycarbonate polyol is preferably 500 or more, more preferably 1,000 or more, and is preferably 5,000 or less, more preferably 4,000 or less, in order to further improve the adhesiveness of the moisture-curable hot melt adhesive of the present invention.

[0119] The glass transition temperature (Tg) of the polycarbonate polyol is preferably in the range of -30 to 20°C, from the viewpoint of further improving drop impact resistance and adhesiveness.

[0120] (glass transition temperature: Tg) The above-mentioned polyester polyols and polycarbonate polyols are either liquid (glass transition temperature Tg<20°C) or solid at room temperature, and the polyester polyols and polycarbonate polyols that are solid at room temperature are amorphous (Tg>20°C) or at least partially crystalline.

[0121] <(a2) Compound containing an alkoxysilyl group and an active hydrogen group> The compound (a2) containing an alkoxysilyl group and an active hydrogen group is a compound that reacts with the isocyanate group-terminated urethane prepolymer (a1), and is a compound having an alkoxysilyl group and an active hydrogen group, and preferably has an active hydrogen group and an alkoxysilyl group at its terminal, and more preferably has at least one active hydrogen group at its terminal.

[0122] The compound (a2) containing an alkoxysilyl group and an active hydrogen group may have active hydrogen groups at both the terminal and randomly distributed portions excluding the terminal. 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 0.5 or more, and even more preferably 0.8 or more hydroxyl groups, from the viewpoint of improving the final strength and heat resistance due to the crosslinking reaction of the alkoxysilyl groups. The compound (a2) preferably has an average of 1.7 or less hydroxyl groups, more preferably 1.4 or less, and even more preferably 1.2 or less hydroxyl groups, from the viewpoint of reducing the molecular weight of the alkoxysilyl group-containing urethane prepolymer (A) and lowering the viscosity of the polymer. Compounds having a single hydroxyl group at the terminal are particularly preferred. The boiling point of the compound having an active hydrogen group is preferably 100°C or higher, more preferably 150°C or higher, and even more preferably 200°C or higher.

[0123] ((a2-1) Methyl methacrylate polymer that is solid at room temperature and has an alkoxysilyl group and a hydroxyl group at its terminal) The moisture-curable hot melt adhesive of the present invention contains, as component (a2), (a2-1) a methyl methacrylate polymer that is solid at room temperature and has an alkoxysilyl group and a hydroxyl group at its terminal, as an essential component. Component (a2-1) preferably has an alkoxysilyl group, and may 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)acrylic acid ester polymer described below.

[0124] It is preferable to introduce one hydroxyl group into the alkoxysilyl group-containing methyl methacrylate polymer. When the alkoxysilyl group-containing methyl methacrylate polymer has only one hydroxyl group, gelation can be suppressed. Here, various known methods can be used to introduce hydroxyl groups into the alkoxysilyl group-containing methyl methacrylate polymer. Examples of methods for introducing hydroxyl groups include the following methods. Note that the hydroxyl group may be introduced at a position other than the terminal, or a monomer having a hydroxyl group may be added separately.

[0125] (1) Copolymerizing an unsaturated compound having a hydroxyl group. (2) Polymerization is carried out using an initiator or chain transfer agent having a hydroxyl group. (3) Reaction using a thiol compound having a hydroxyl group, or polymerization using a thiol compound having a hydroxyl group and a metallocene compound. For method (3), the method described in Japanese Patent No. 5222467 can be used.

[0126] As a method for introducing a hydroxyl group, from the viewpoint of being able to introduce one hydroxyl group, a method of 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.

[0127] The number (average) of hydroxyl groups in component (a2-1) per polymer molecule of component (a2-1) is preferably 0.5 or less, more preferably 0.3 or less, and even more preferably 0.1 or less. The number average molecular weight of component (a2-1) is preferably 1,000 or more, more preferably 2,000 or more, and even more preferably 3,000 or more, and is preferably 50,000 or less, more preferably 30,000 or less, and even more preferably 15,000 or less.

[0128] (Copolymerization of unsaturated compounds having hydroxyl groups) The unsaturated compound having a hydroxyl group is preferably a (meth)acrylic acid alkyl ester having a hydroxyl group. Examples of such compounds include monohydroxyacrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl acrylate; and polyhydroxyacrylates such as glycerin mono(meth)acrylate. Among these, monohydroxyacrylates are preferred. 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 per hydroxyl group per molecule of the polymer of component (a2-1) is 0.5 to 3, and more preferably 1.1 to 2.

[0129] ((a2-2) Alkoxysilane having an active hydrogen group) The moisture-curable hot melt adhesive according to the present invention may contain a residue obtained by removing an active hydrogen group from an alkoxysilane having an amino group, a hydroxyl group, or a mercapto group. Examples of the active hydrogen group include an amino group, a hydroxyl group, or a mercapto group. Examples of the alkoxysilane (a2-2) having an active hydrogen group include compounds represented by the following general formula (VII):

[0130] [ka]

[0131] In general formula (VII), R 8 represents a linear or branched monovalent hydrocarbon radical having 1 to 12 carbon atoms, optionally containing one or more C-C multiple bonds and / or optionally containing alicyclic and / or aromatic moieties. In particular, R 8 represents a methyl, ethyl, or isopropyl group. 9represents an acyl residue or a linear or branched monovalent hydrocarbon group having 1 to 12 carbon atoms, optionally containing one or more C-C multiple bonds and / or optionally containing alicyclic and / or aromatic moieties. 9 is preferably an acyl or alkyl group having 1 to 5 C atoms, in particular a methyl, ethyl or isopropyl group. 10 R represents a linear or branched divalent hydrocarbon group having 1 to 12 carbon atoms, optionally containing cyclic and / or aromatic moieties, and optionally containing one or more heteroatoms. 10 is preferably an alkylene residue having 1 to 3 C atoms, particularly 3 C atoms. In general formula (VII), a represents 0, 1 or 2, particularly 0 or 1. The group X is the same as above.

[0132] Compounds represented by 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, etc.); secondary aminosilanes (e.g., N-butyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, etc.); Michael-type adducts of primary aminosilanes (e.g., N-(3-trimethoxysilylpropyl)aminosuccinic acid dimethyl and diethyl ester); and analogs of the above aminosilanes having ethoxy or isopropoxy groups instead of the silicon-bonded methoxy group. Particularly suitable aminosilanes include secondary aminosilanes, particularly those represented by the general formula (VIII): 5 is not H. Michael-type adducts are preferred, and N-(3-trimethoxysilylpropyl)aminosuccinic acid diethyl ester is particularly preferred.

[0133] [ka]

[0134] In general formula (VIII), R 8 , R 9 , R 10 , R 5 , and a are the same as above.

[0135] (Block polymer structure) The alkoxysilyl group-containing urethane prepolymer (A) according to the present invention has a "(hard segment)-(soft segment)-(hard segment)" type block polymer structure composed of a "hard segment" of a methyl methacrylate copolymer that is solid at room temperature and a "soft segment" of polyether, which imparts toughness to moisture-curing hot melt adhesives and improves their build-up strength. Furthermore, by incorporating a crystalline polyester into the polyether "soft segment," it is possible to impart sufficient bonding time and improve build-up strength.

[0136] Furthermore, the crosslinking reaction of the alkoxysilyl groups in the hard segments can further improve the adhesiveness and heat resistance.

[0137] Furthermore, because the block polymer structure has a polyether backbone (PE backbone), a crystalline polyester backbone (PEs backbone), and a methyl methacrylate copolymer backbone (PAc backbone), it acts as a compatibilizer for polyether, crystalline polyester, and methyl methacrylate copolymer, and can make crystalline polyester and methyl methacrylate copolymer, which are incompatible on their own, compatible.

[0138] (weight ratio of each skeleton) 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 100 parts by weight, is preferably 15 parts by weight or more and 55 parts by weight or less, the PEs skeleton is preferably 15 parts by weight or more and 50 parts by weight or less, and the PAc skeleton is preferably 10 parts by weight or more and 45 parts by weight or less.

[0139] (Compounds with one active hydrogen group and no alkoxysilyl groups) By using a compound having one active hydrogen group reactive with isocyanate groups but no alkoxysilyl groups (hereinafter referred to as a compound having only one active hydrogen group), the number of silyl groups in the alkoxysilyl group-containing urethane prepolymer (A) can be adjusted (i.e., reduced). This allows the crosslink density after curing of the alkoxysilyl group-containing urethane prepolymer (A) to be adjusted, thereby adjusting the flexibility and / or elongation of the cured coating. Examples of active hydrogen groups reactive with isocyanate groups include hydroxyl groups, amino groups, and mercapto groups. Hydroxyl groups and amino groups are preferred, and secondary amino groups are more preferred from the perspective of stable production of moisture-curable hot melt adhesives. A compound having only one active hydrogen group may also be used as component (a3).

[0140] 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 a functional group other than a hydroxyl group such as propylene glycol monoacetate and diethylene glycol monoacetate, and alcohols having a polyoxyalkylene chain such as polyoxypropylene monool. Examples of compounds having one amino group as an active hydrogen group include primary amines such as octylamine, dodecylamine, cetylamine, stearylamine, and behenylamine; and secondary amines such as dibutylamine, butyloctylamine, dioctylamine, distearylamine, and butylstearylamine.

[0141] <Number of crosslinkable silicon groups> From the viewpoint of curability, the number of crosslinkable silicon groups in one molecule of (A) alkoxysilyl group-containing urethane prepolymer is preferably 1.0 or more, more preferably 1.2 or more, even more preferably 1.4 or more, and particularly preferably 1.6 or more, on average, and from the viewpoint of physical properties, it is preferably 4.0 or less, more preferably 3.0 or less, even more preferably 2.0 or less, and particularly preferably 1.8 or less, on average.

[0142] <(B) Silane-based adhesion promoter> The moisture-curable hot melt adhesive of the present invention can further contain (B) a silane-based adhesion promoter, which exhibits an adhesion promoter effect upon moisture curing, improving the final strength other than the initial adhesive strength, water-resistant adhesion, and heat-resistant adhesion.

[0143] Here, the alkoxysilyl group of the (B) silane adhesion promoter is preferably a methoxy group, an ethoxy group, or the like, from the viewpoint of hydrolysis rate. The number of alkoxy groups in the silyl group is preferably two or more, more preferably three. Furthermore, the functional group of the (B) silane adhesion promoter is preferably an amino group, an epoxy group, or the like, from the viewpoint of adhesiveness, with an amino group being more preferred. As the (B) silane adhesion promoter, 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.

[0144] 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-based silanes include N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine. Examples of epoxy silanes include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane. Examples of acrylic silanes include 3-methacryloxypropyltrimethoxysilane. Examples of vinyl silane coupling agents include vinyltrimethoxysilane, methylvinyldimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, and allyltri(β-methoxysilane). Examples of mercaptosilanes include 3-mercaptopropyltrimethoxysilane. Examples of urea silane coupling agents include 3-ureidopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane. Examples of isocyanurate silanes include tris-(trimethoxysilylpropyl)isocyanurate. Examples of the isocyanate silane include 3-isocyanate propyl triethoxy silane.

[0145] Further examples of the (B) silane-based adhesion promoter include aminosilane reactants such as the reaction product of the above-mentioned aminosilane with an epoxy silane, the reaction product of an aminosilane with an isocyanate silane, the reaction product of an aminosilane with a silane having a (meth)acryloyloxy group, the reaction product of an aminosilane with an epoxy resin (such as bisphenol A diglycidyl ether or phenyl glycidyl ether), the reaction product of an aminosilane with a polyisocyanate, and the reaction product of an aminosilane with a polyacrylate; condensates obtained by partially condensing the above-mentioned silanes (preferably aminosilane condensates obtained by partially condensing the above-mentioned aminosilane, isocyanate silane, aminosilane reactant, and a mixture of the reactants); and modified derivatives of these, such as amino-modified silyl polymers, silylated amino polymers, unsaturated aminosilane complexes, phenylamino long-chain alkylsilanes, aminosilylated silicones, silylated polyesters, and photoaminosilane generators.

[0146] As for the molecular weight of (B) the silane adhesion promoter, compounds with a molecular weight of 320 or more are preferred because they are less likely to volatilize when the hot melt adhesive melts, with 400 or more being more preferred, and 450 or more being even more preferred. Silane adhesion promoters having two or more silyl groups, such as bis-silylaminosilane, isocyanurate silane, aminosilane reactants, and aminosilane condensates, are more preferred because of their adhesiveness and less likely to volatilize when the hot melt adhesive melts, with aminosilane reactants and aminosilane condensates being even more preferred, and aminosilane reactants being the most preferred. Note that the aminosilane reactant may be reacted by separately adding the reactive materials during the mixing step.

[0147] (B) The silane adhesion promoter may be used alone or in combination of two or more. The amount of (B) silane adhesion promoter used is preferably 0.01 part by mass or more, more preferably 0.1 part by mass or more, and particularly preferably 1 part by mass or more, per 100 parts by mass of component (A), and is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less. If it is less than 0.01 part by mass, the adhesion-imparting effect and the effect as a curing catalyst are insufficient, while if it exceeds 20 parts by mass, the catalytic action corresponding to the added amount is not significant and is not economically preferable.

[0148] (Photoaminosilane generator) When the hot melt adhesive according to the present invention is configured as a photocurable adhesive, a compound (hereinafter also referred to as a photoaminosilane generator) can be used that does not generate a compound having an amino group before light irradiation but generates an amino group-containing silane upon light irradiation. Examples of photoaminosilane generators include compounds described in WO 2015-088021 in which the photofunctional group is an o-nitrobenzyl group, a p-nitrobenzyl group, an oxime residue, a benzyl group, a benzoyl group, or a substituted version of these groups. Examples of photoaminosilane generators in which the photofunctional group is an o-nitrobenzyl group 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. An example of a photoaminosilane generator in which the photofunctional group is a p-nitrobenzyl group is 4-nitrobenzyl-N-[3-(trimethoxysilyl)propyl]carbamate. An example of a photoaminosilane generator in which the photofunctional group is a benzyl group is 1-(3,5-dimethoxyphenyl)-1-methylethyl-N-[3-(trimethoxysilyl)propyl]carbamate. An example of a photoaminosilane generator in which the photofunctional group is an oxime residue is benzophenone O-{[3-(trimethoxysilyl)propyl]}oxime.

[0149] <(C) Modified Resin> (C) Modifier Resin is mixed to control the bonding time of the compounded system and to reduce the melt viscosity, and has the function of modifying and adjusting physical properties. (C) Modifier Resin can improve the bonding time and initial adhesive strength.

[0150] Component (C) according to the present invention exhibits different functions depending on the type of segments constituting the resin to which component (C) is added. That is, when component (C) is added to a resin mainly composed of hard segments, it functions as a modifying resin to adjust physical properties, and when added to a resin mainly composed of soft segments, it functions as a tackifying resin. Since the skeleton of component (A) according to the present invention is mainly composed of hard segments, the resins exemplified below act as modifying resins.

[0151] (C) Examples of modified resins include terpene resins, aromatic modified terpene resins and hydrogenated terpene resins obtained by hydrogenating these, terpene-phenol resins obtained by copolymerizing terpenes and 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, DCPD resins, etc. These can be used alone or in combination of two or more.

[0152] Examples of styrene block copolymers and hydrogenated products thereof include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylenebutylene-styrene block copolymer (SEBS), styrene-ethylenepropylene-styrene block copolymer (SEPS), and styrene-isobutylene-styrene block copolymer (SIBS).

[0153] As the (C) modifying resin, terpene phenol resins and aromatic petroleum resins are preferred from the viewpoints of good compatibility with organic polymers having crosslinkable silicon groups and good heat stability of the adhesive. As the aromatic petroleum resin, aromatic styrene resins and aliphatic-aromatic copolymer styrene resins are preferred, and terpene phenol resins and aliphatic-aromatic copolymer styrene resins are more preferred. Furthermore, from the viewpoints of VOC and fogging, it is preferred to use aliphatic-aromatic copolymer styrene resins.

[0154] The amount of (C) modified resin added per 100 parts by mass of component (A) is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and particularly preferably 30 parts by mass or more, and is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and particularly preferably 120 parts by mass or less.

[0155] <(D) Crosslinking catalyst> (D) Crosslinking catalysts include crosslinking catalysts (silanol catalysts) for alkoxysilyl group-containing urethane prepolymers, such as titanate esters, tetravalent organotin compounds, divalent organotin compounds such as tin octoate, zirconium compounds, aluminum compounds, bismuth compounds, primary and 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 their carboxylates, and fluorinated polymers. These (D) crosslinking catalysts can be used alone or in combination of two or more.

[0156] Examples of the fluorinated polymer include organic polymers having Si-F bonds, such as the organic polymers having fluorosilyl groups (hereinafter also referred to as "fluorinated polymers") described in WO2015-088021. Preferred fluorinated polymers are polymers having fluorosilyl groups, such as difluoromethylsilyl groups, difluoromethoxysilyl groups, difluoroethoxysilyl groups, and trifluorosilyl groups, at the ends of the main chain or side chains.

[0157] The main chain skeleton of the fluorinated polymer can be a polymer described in the liquid polymer compound section described later, and among these polymers, polyoxyalkylene polymers and / or (meth)acrylic acid ester polymers are preferred because they are easy to handle and have a significant effect of extending the lamination time. The number average molecular weight of the fluorinated polymer, as calculated as polystyrene by GPC, is preferably 3,000 or more and 100,000 or less, more preferably 50,000 or less, and particularly preferably 30,000 or less.

[0158] When a fluorinated polymer is used, the amount thereof is preferably 0.01 part by mass or more, more preferably 0.05 part by mass or more, and even more preferably 0.1 part by mass or more, relative to 100 parts by mass of the (A) alkoxysilyl group-containing urethane prepolymer, 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.

[0159] Furthermore, as the (D) crosslinking catalyst, from the viewpoint of high catalytic effect and sufficient heat resistance, titanate esters, tetravalent organotin compounds, divalent organotin compounds, tertiary amine compounds, amidine compounds or their carboxylates, and fluorinated polymers are preferred. In particular, as the (D) crosslinking catalyst, from the viewpoint of resistance to scission of silyl crosslinks due to wet heat and resistance to deterioration of physical properties, at least one catalyst selected from the group consisting of tertiary amine compounds, divalent tin compounds, fluorinated polymers, and titanate esters is preferred, at least one catalyst selected from the group consisting of tertiary amine compounds, divalent tin compounds, and fluorinated polymers is more preferred, and fluorinated polymers are particularly preferred.

[0160] Furthermore, from the viewpoint of preventing transesterification reactions of low molecular weight alcohols (e.g., methanol or ethanol) resulting from decomposition of polyester units and / or alkoxy terminal groups present in prepolymers such as component (A) (hot melt adhesives are melted in a heating oven before application and maintained in a liquid state for a relatively long period of time (generally at least one working day), sufficient stability at high temperatures is required for industrial use), divalent organotin compounds, tertiary amine compounds, and fluorinated polymers are preferred. Furthermore, when a fluorinated polymer is used, the crosslinking reaction is further promoted when it is used in combination with a ketimine structure-containing alkoxysilane.

[0161] When a crosslinking catalyst other than the fluorinated polymer is used, the amount of the other crosslinking 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, relative to 100 parts by mass of the (A) alkoxysilyl group-containing urethane prepolymer, 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.

[0162] (Photobase Generator) When the hot melt adhesive according to the present invention is configured as a photocurable adhesive, a photolatent amine compound that does not have catalytic activity before irradiation with light but generates an amine compound upon irradiation with light can be used. Examples of photolatent amine compounds that can be used include 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 the photobase generator, as the generated base exhibits high catalytic activity. Benzyl ammonium salt derivatives, benzyl-substituted amine derivatives, α-aminoketone derivatives, and α-ammonium ketone derivatives are preferred due to their efficient base generation and good storage stability as a composition. Benzyl ammonium salt derivatives and benzyl-substituted amine derivatives are particularly preferred, as they do not generate a base when not exposed to light but efficiently generate a base when exposed to light. Specifically, various photobase generators described in International Publication No. WO 2015 / 008709 can be used. These photobase generators may be used alone or in combination of two or more.

[0163] <(E) Silylated Polymer> (E) The silylated polymer is mixed into the reactive hot melt adhesive for the purpose of controlling the bonding time of the reactive hot melt adhesive and reducing the melt viscosity, and has the function of modifying and / or adjusting the physical properties of the reactive hot melt adhesive. The silylated polymer can improve application workability and initial adhesive strength.

[0164] Examples of silylated polymers include silylated polyurethanes and silyl-terminated polymers, and examples of silylated polyurethanes include silylated polyurethane 1 and silylated polyurethane 2, which will be described in detail below. From the viewpoint of providing a tough cured product and good reactivity, silylated polyurethanes are preferred, and of these, silylated polyurethane 2 is more preferred. Furthermore, from the viewpoint of reducing the melt viscosity of the adhesive and improving application workability, silyl-terminated polymers and silylated polyurethane 1 are preferred, and silyl-terminated polymers are more preferred.

[0165] Furthermore, from the viewpoint of improving the adhesive application workability, bonding time, initial strength, and final strength, a silylated polyurethane that is solid at room temperature and has a crystalline aliphatic polyester skeleton and / or a crystalline polycarbonate skeleton is preferred, a silylated polyurethane that has a crystalline aliphatic polyester skeleton is more preferred, and a silylated polyurethane that has a long-chain aliphatic polyester skeleton is even more preferred.

[0166] From the viewpoint of reducing the melt viscosity of the adhesive and improving the flexibility of the cured coating, silylated polymers having a polyoxyalkylene skeleton that are liquid at room temperature are preferred, silylated polymers having a polyoxypropylene skeleton are more preferred, and silyl-terminated polyethers having a polyoxypropylene skeleton are even more preferred. Here, from the viewpoint of enhancing the effect of reducing the melt viscosity of the adhesive, long-chain alkyl polyesters having a number-average molecular weight of 1,000 to 2,000 are particularly preferred. Furthermore, from the viewpoint of further improving the adhesive's adhesion to aromatic resins such as polyethylene terephthalate and imparting toughness to improve final strength, silylated polyurethanes having an aromatic polyester skeleton are preferred, and silylated polyurethanes having an aromatic polyester skeleton that is solid at room temperature are more preferred. Among these, aromatic polyesters having a number-average molecular weight of 1,000 to 2,000 are preferred from the viewpoint of being able to reduce the melt viscosity.

[0167] Specifically, the silylated polymer is an organic polymer having a crosslinkable silicon group. Examples of the crosslinkable silicon group include the group represented by general formula (IX) described in the section "Alkoxysilyl Group-Containing Methyl Methacrylate Polymer" below. When the silylated polymer has a plurality of crosslinkable silicon groups, the crosslinkable silicon groups may be one type or two or more types in combination. The crosslinkable silicon groups may be bonded to the main chain or side chain of the polymer, or to both. From the viewpoint of achieving excellent physical properties of the cured product, such as tensile properties, it is preferable that the crosslinkable silicon groups be present at the molecular chain terminals.

[0168] The number of crosslinkable silicon groups present in one silylated polymer molecule is preferably from 1.0 to 5, and more preferably from 1.1 to 3. If the number of crosslinkable silicon groups in a molecule is less than 1, curability will be insufficient, while if there are too many, the network structure will be too dense and the polymer will not exhibit good mechanical properties.

[0169] Furthermore, when crosslinkable silicon groups are present at the molecular chain terminals, the compounding ratio of the molecular chain terminal group-containing component to the crosslinkable silicon group-containing component is preferably 0.3 moles or more, more preferably 0.5 moles or more, and even more preferably 0.7 moles or more of crosslinkable silicon groups per mole of molecular chain terminal groups. The crosslinkable silicon group-containing component may be added in excess relative to the molecular chain terminal groups. In this case, the excess crosslinkable silicon group-containing component functions as an adhesion promoter. If unreacted hydroxyl groups remain, they are preferably inactivated by reacting them with a monoisocyanate. Examples of monoisocyanates include monoisocyanates having an isocyanate group bonded to a C6-C18 alkyl group or a C6-C18 aryl group. Examples of preferred monoisocyanates include stearyl isocyanate, phenyl isocyanate, and naphthyl isocyanate.

[0170] [Silylated Polyurethane 1] Silylated polyurethane 1 can be prepared by reacting an isocyanate silane with a polymer having hydroxyl groups. Examples of silylated polyurethane 1 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, which are prepared by reacting an isocyanate silane with a polymer having hydroxyl groups, such as polyester polyol, polycarbonate polyol, or polyoxyalkylene polyol. The polymer having hydroxyl groups may be a polymer having hydroxyl groups linked by a diisocyanate.

[0171] [Silylated Polyurethane 2] 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 ratio of active hydrogen groups to isocyanate groups is stoichiometrically 1:1, or the ratio of reactive groups is such that there is a slight excess of isocyanate groups, so that the resulting silylated polyurethane 2 contains no isocyanate groups. Polyurethane polymers containing isocyanate groups are prepared, for example, by reacting multiple polyols with diisocyanates. Specifically, silylated polyether urethane 2 having a polyoxyalkylene skeleton can be prepared using a polyoxyalkylene polyol as the polyol.

[0172] Suitable polyols are in particular polyether polyols, polyester polyols and polycarbonate polyols, as well as mixtures of these polyols, with polyoxyalkylene polyols being preferred.

[0173] [Silyl-terminated polymer] Silyl-terminated polymers can be prepared by, for example, hydrosilylation of a polymer having a terminal double bond. The polymer having a terminal double bond 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.

[0174] [Silyl-terminated polyether] Silyl-terminated polyethers can be obtained, for example, by reacting an unsaturated group-containing polyoxyalkylene polymer with a hydrosilane having a crosslinkable silicon group or a mercapto compound having a crosslinkable silicon group to hydrosilylate or mercaptoate. This synthesis method is a method for obtaining a polyoxyalkylene polymer having a crosslinkable silicon group (silyl-terminated polyether), and an example of this synthesis method is the preparation by hydrosilylation of an allyl-terminated polyoxyalkylene polymer described in JP 2006-077036 A. The unsaturated group-containing polyoxyalkylene polymer 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 and an unsaturated group that is reactive with the functional group.

[0175] [Silyl-terminated polyacrylate] The silyl-terminated polyacrylate comprises at least one acrylate component and at least one silyl component. The silyl-terminated polyacrylate can be obtained, for example, by the reaction of an alkenyl-terminated acrylate by hydrosilylation. The alkenyl-terminated acrylate can be 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. The alkenyl-terminated acrylate can be obtained by a production method using atom transfer radical polymerization (ATRP). The silyl-terminated polyacrylate is preferably a silyl-terminated polyacrylate that is liquid at room temperature and has flexibility and is mainly composed of butyl acrylate.

[0176] [Polyoxyalkylene polymer] The main skeleton of the polyoxyalkylene polyol and the unsaturated group-containing polyoxyalkylene polymer is preferably a polyoxyalkylene polymer having a repeating unit represented by the following general formula (α).

[0177] -R β -O- (α)

[0178] Here, in the general formula (α), R β represents a linear or branched alkylene group having 1 to 14 carbon atoms, preferably 2 to 4 carbon atoms.

[0179] The main chain of the polyoxyalkylene polymer may be composed of only one type of repeating unit or two or more types of repeating units. In particular, in the present invention, an amorphous polyoxypropylene polymer having a relatively low viscosity is preferred.

[0180] Examples of methods for synthesizing polyoxyalkylene polymers include a polymerization method using an alkali catalyst such as KOH, a polymerization method using a composite metal cyanide complex catalyst (e.g., a zinc hexacyanocobaltate glyme complex catalyst), etc. Among these, a polymerization method in which an alkylene oxide is reacted with an initiator in the presence of a composite metal cyanide complex catalyst is preferred because it allows the synthesis of a polymer with a narrow molecular weight distribution.

[0181] Examples of double metal cyanide complex catalysts include Zn3[Co(CN)6]2 (zinc hexacyanocobaltate complex), etc. Catalysts in which alcohols and / or ethers are coordinated as organic ligands to these may also be used.

[0182] The initiator is preferably a compound having at least two active hydrogen groups. Examples of the active hydrogen-containing compound include polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and glycerin, and linear and / or branched polyether compounds having a number average molecular weight of 500 to 20,000.

[0183] Examples of the alkylene oxide include ethylene oxide, propylene oxide, and isobutylene oxide.

[0184] Particularly preferred examples of the polyoxyalkylene polyol include polyoxyethylene polyol and polyoxypropylene polyol, and among these, polyoxyethylene diol, polyoxypropylene diol, polyoxyethylene triol, and polyoxypropylene triol are mentioned.

[0185] Among these, 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 or more and 30,000 g / mol or less, and polyoxyethylene diols, polyoxyethylene triols, polyoxypropylene diols, and polyoxypropylene triols having a molecular weight in the range of 400 g / mol or more and 8,000 g / mol or less are preferred.

[0186] Here, so-called polyoxypropylene polyols terminated with ethylene oxide (i.e., "EO end-capped" compounds) are particularly preferred. EO end-capped polyoxypropylene polyols are special polyoxypropylene polyoxyethylene polyols, prepared, for example, by additionally alkoxylating pure polyoxypropylene polyols, particularly polyoxypropylene diols and triols, with ethylene oxide after the polyoxypropylation reaction is completed, resulting in primary hydroxyl groups. Polypropylene glycol (PPG) has secondary hydroxyl groups and is flexible, but its reactivity is inferior to that of compounds with primary hydroxyl groups. Therefore, in the present invention, it is preferable to use EO end-capped compounds with primary hydroxyl groups to improve reactivity. In this case, it is preferable to use polyoxypropylene polyoxyethylene diols and / or polyoxypropylene polyoxyethylene triols.

[0187] Such polyols preferably have an average molecular weight of 250 to 30,000 g / mol, in particular 1,000 to 30,000 g / mol, and an average OH functionality in the range of 1.6 to 3.

[0188] As the polyol, polyether polyols are preferred, and in particular polyoxyethylene polyols, polyoxypropylene polyols, and polyoxypropylene polyoxyethylene polyols are more preferred, and polyoxyethylene diols, polyoxypropylene diols, polyoxyethylene triols, polyoxypropylene triols, polyoxypropylene polyoxyethylene diols, and polyoxypropylene polyoxyethylene triols are even more preferred.

[0189] <Alkoxysilyl group-containing methyl methacrylate polymer> Component (A) may contain an alkoxysilyl group-containing methyl methacrylate polymer. The alkoxysilyl group-containing methyl methacrylate polymer is a (meth)acrylic ester polymer containing methyl methacrylate as an essential monomer. The alkoxysilyl group-containing methyl methacrylate polymer imparts toughness to the moisture-curable hot melt adhesive, improving the initial strength and final strength. Furthermore, the crosslinking reaction of the alkoxysilyl group can improve the heat resistance of the moisture-curable hot melt adhesive.

[0190] The alkoxysilyl group of the (meth)acrylic ester polymer, which is an alkoxysilyl group-containing methyl methacrylate polymer, has an alkoxysilyl group and a glass transition temperature of -20° C. to 120° C. The alkoxysilyl group has an alkoxy group bonded to a silicon atom and is a group that can be crosslinked by a silanol condensation reaction. Examples of the alkoxysilyl group include groups represented by the following general formula (IX):

[0191] [ka]

[0192] In 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; R 11 When two or more X's are present, they may be the same or different. X represents an alkoxy group, and when two or more X's are present, they may be the same or different. a represents 0, 1, 2, or 3. In the alkoxysilyl group of general formula (IX), it is preferable that a is 2 or 3. When a is 3, the curing rate is higher than when a is 2.

[0193] R 11 Specific examples of the alkyl group include alkyl groups such as methyl and ethyl groups, substituted alkyl groups such as methoxymethyl groups, and cycloalkyl groups such as cyclohexyl groups. Of these, methyl groups are preferred, and from the viewpoint of increasing the curing rate, substituted alkyl groups in which the α-carbon is substituted with a polar group are preferred.

[0194] The alkoxy group represented by X is not particularly limited, and may be any conventionally known alkoxy group. Among alkoxy groups, groups with fewer carbon atoms have higher reactivity, and the reactivity decreases as the number of carbon atoms increases, in the order of methoxy group > ethoxy group > propoxy group. Although it can be selected depending on the purpose and application, methoxy group or ethoxy group is usually used. In the case of an alkoxysilyl group represented by general formula (IX), a is preferably 2 or more in consideration of curability.

[0195] Specifically, as the alkoxysilyl group, a trimethoxysilyl group or a triethoxysilyl group is preferred from the viewpoint of high reactivity, and a trimethoxysilyl group is more preferred, and a methyldimethoxysilyl group or a methyldiethoxysilyl group is preferred from the viewpoint of obtaining a flexible cured product.

[0196] The alkoxysilyl group may be used alone or in combination of two or more types. The alkoxysilyl group may be present in the main chain, the side chain, or both.

[0197] The number (average) of alkoxysilyl groups in the alkoxysilyl group-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 curability will be insufficient, and if it is too many, the network structure will be too dense and will not exhibit good mechanical properties.

[0198] In preparing the alkoxysilyl group-containing methyl methacrylate polymer, various known methods can be used to introduce alkoxysilyl groups into the (meth)acrylic acid ester polymer. For example, the following method can be mentioned as an example of a method for introducing alkoxysilyl groups.

[0199] (1) Copolymerizing an unsaturated compound having an alkoxysilyl group. (2) Polymerization is carried out using an initiator or chain transfer agent having an alkoxysilyl group. (3) A (meth)acrylic acid ester polymer having a functional group such as a hydroxyl group is reacted with a compound having an alkoxysilyl group and another functional group capable of reacting with the functional group, such as an epoxysilane.

[0200] Among these methods for introducing alkoxysilyl groups, (1) copolymerization of an unsaturated compound having an alkoxysilyl group is preferred from the viewpoint of ease of introduction of the alkoxysilyl group. A combination of methods (1) and (2) is also preferred. For example, a trimethoxysilyl group-containing (meth)acrylic polymer can be obtained as an alkoxysilyl group-containing methyl methacrylate polymer by using methyl methacrylate, 2-ethylhexyl methacrylate, 3-methacryloxypropyltrimethoxysilane, titanocene dichlide as a metal catalyst, 3-mercaptopropyltrimethoxysilane (which acts as an initiator and also as a chain transfer agent due to the action of titanocene dichlide), and a benzoquinone solution as a polymerization terminator in accordance with Synthesis Example 4 of WO2015-088021.

[0201] (Unsaturated compounds having an alkoxysilyl group) The unsaturated compound having an alkoxysilyl group used in copolymerization is preferably a (meth)acrylic acid alkyl ester or vinyl silane having an alkoxysilyl group. Examples of such compounds include 3-(meth)acryloxypropyl alkoxysilanes such as 3-(meth)acryloxypropyl trimethoxysilane, 3-(meth)acryloxypropyl methyl dimethoxysilane, and 3-(meth)acryloxypropyl triethoxysilane, and vinyl alkoxysilanes such as vinyl triethoxysilane. Among these, a (meth)acrylic acid alkyl ester having a substituted alkyl group in which the alkyl group having an alkoxysilyl group has 3 or less carbon atoms is preferred. The blending ratio of the unsaturated compound having an alkoxysilyl group is preferably such that the number of alkoxysilyl groups in the unsaturated bond having an alkoxysilyl group is, on average, 1.1 to 5, preferably 1.1 to 3, per alkoxysilyl group per molecule of the alkoxysilyl group-containing methyl methacrylate polymer.

[0202] (Monomers other than those having an alkoxysilyl group used in alkoxysilyl group-containing methyl methacrylate polymers) Examples of monomers other than the monomer having an alkoxysilyl group used in the alkoxysilyl group-containing methyl methacrylate polymer include methyl methacrylate random copolymers having a repeating unit represented by general formula (X), which contain methyl methacrylate as an essential monomer component.

[0203] -CH2C(R 12 )(COOR 13 )- (X)

[0204] In general formula (X), R 12 is a hydrogen atom or a methyl group, R 13 represents a hydrocarbon group which may have a substituent. The (meth)acrylic acid ester represents an acrylic acid ester and / or an alkyl methacrylic acid ester.

[0205] As a monomer that becomes another repeating unit other than methyl methacrylate (MMA), a (meth)acrylic acid alkyl ester is preferable. Examples of the (meth)acrylic acid alkyl ester compound include known compounds. For example, methyl acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc. can be mentioned.

[0206] From the viewpoint of good compatibility with the polyether skeleton of the isocyanate group-terminated urethane prepolymer having a polyether skeleton (i.e., part of the skeleton of component (A)), (meth)acrylic acid alkyl esters having an ester bond with 8 or more carbon atoms, such as 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate, are preferred. From the viewpoint of making the methyl methacrylate polymer flexible, it is preferred to use (meth)acrylic acid alkyl esters 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). Note that the glass transition temperature in this paragraph is the glass transition temperature of the homopolymer.

[0207] The hydrocarbon group, such as the alkyl group, of the (meth)acrylic acid ester may have a substituent, such as a hydroxyl group, an alkoxy group, a halogen atom, or an epoxy group. Examples of such compounds include (meth)acrylic acid esters having a hydroxyl group, such as hydroxyethyl (meth)acrylate, (meth)acrylic acid esters having an alkoxy group, such as methoxyethyl (meth)acrylate, (meth)acrylic acid esters having an epoxy group, such as glycidyl (meth)acrylate, and (meth)acrylic acid esters having an amino group, such as diethylaminoethyl (meth)acrylate. It is also possible to use unsaturated compounds (macromonomers or macromers) having a polymer chain, such as acrylic acid esters having a polystyrene chain.

[0208] Furthermore, the alkoxysilyl group-containing (meth)acrylic acid ester polymer of the alkoxysilyl group-containing methyl methacrylate polymer may contain, in addition to the repeating units derived from the (meth)acrylic acid ester compound, repeating units derived from a compound copolymerizable therewith. Examples of compounds copolymerizable with the (meth)acrylic acid ester compound include acrylic acids such as (meth)acrylic acid; amide compounds such as (meth)acrylamide; vinyl ether compounds such as alkyl vinyl ether; and others such as acrylonitrile, styrene, α-methylstyrene, vinyl chloride, and vinyl acetate.

[0209] (Monomer usage ratio) The amount of monomer used in the alkoxysilyl group-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 most preferably 95% by mass or more, based on the total amount of the alkoxysilyl group-containing methyl methacrylate polymer. It is particularly preferred to use acrylic acid alkyl esters such as methyl methacrylate and butyl acrylate, which do not have an alkyl group with a carbon number of 2 to 30, in the amounts described above. A macromonomer may also be used as the monomer in the alkoxysilyl group-containing methyl methacrylate polymer. However, when a macromonomer is used, the amount of the macromonomer in the alkoxysilyl group-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.

[0210] (glass transition temperature) The alkoxysilyl group-containing (meth)acrylic acid ester polymer of the alkoxysilyl group-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, even more preferably 20°C or higher, and preferably 120°C or lower, more preferably 100°C or lower, and even more preferably 80°C or lower. If the glass transition temperature is lower than -20°C, the adhesive strength immediately after bonding tends to be poor. If the glass transition temperature exceeds 120°C, the melt viscosity increases, making it difficult to apply the hot melt adhesive to the adherend. The glass transition temperature can be easily estimated from the type and amount of the monomer components using the Fox equation below.

[0211] 1 / Tg=W1 / Tg1+W2 / Tg2++W n / Tg n (Fox style)

[0212] In the above Fox formula, Tg is the glass transition temperature (K) of the acrylic resin, and W1, W2, ..., W n are the weight fractions of each monomer, and Tg1, Tg2, . . ., Tg nis 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 literature, such as Mitsubishi Rayon Co., Ltd.'s Acrylic Ester Catalog (1997 edition) or Kyozo Kitaoka, "New Polymer Library 7: Introduction to Synthetic Resins for Paints," Polymer Publishing Association, pp. 168-169.

[0213] The molecular weight of the alkoxysilyl group-containing (meth)acrylic acid ester polymer of the alkoxysilyl group-containing methyl methacrylate polymer is preferably 3,000 or more, more preferably 4,000 or more, even more preferably 5,000 or more, and is preferably 200,000 or less, more preferably 100,000 or less, and even more preferably 50,000 or less, in terms of number average molecular weight (polystyrene equivalent molecular weight measured by GPC method). If the number average molecular weight is less than 3,000, the initial adhesive strength after application is low, and if it exceeds 200,000, the viscosity during application becomes too high, reducing workability. In addition, the alkoxysilyl group-containing methyl methacrylate polymer is preferably a solid at room temperature.

[0214] (Method for Polymerizing Alkoxysilyl Group-Containing Methyl Methacrylate Polymer) Radical polymerization can be used as a polymerization method for the alkoxysilyl group-containing methyl methacrylate polymer. For example, conventional solution polymerization or bulk polymerization using a thermal polymerization initiator such as benzoyl peroxide or azobisisobutyronitrile can be used. Polymerization using a photopolymerization initiator and light or radiation irradiation can also be used. In radical copolymerization, a chain transfer agent such as lauryl mercaptan or 3-mercaptopropyltrimethoxysilane can be used to adjust the molecular weight. Radical polymerization using a thermal polymerization initiator can also be used, and this method can easily produce the alkoxysilyl group-containing methyl methacrylate polymer of the present invention. Other polymerization methods, such as living radical polymerization as described in JP 2000-086998 A, can also be used.

[0215] <Other additives> The reactive hot melt adhesive of the present invention can contain other additives as needed. Examples of such additives include liquid polymer compounds, fillers, diluents, stabilizers, flame retardants, curing regulators, radical inhibitors, metal deactivators, antiozonants, phosphorus-based peroxide decomposers, lubricants, pigments, foaming agents, and antifungal agents. These additives can be used alone or in combination of two or more.

[0216] (liquid polymer compound) The liquid polymer compound has the effect of reducing the viscosity of the hot melt adhesive when it is melted. Furthermore, the liquid polymer compound has the effect of extending the bonding time (the time during which bonding can be performed after hot melt application). The viscosity of the liquid polymer compound at room temperature (as measured with a Brookfield viscometer) is preferably 100 Pa·s or less, more preferably 75 Pa·s or less, and particularly preferably 50 Pa·s or less.

[0217] Examples of the main chain skeleton of the liquid polymer compound include polyoxyalkylene polymers such as polyoxypropylene, polyoxytetramethylene, 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 condensation of dibasic acids such as adipic acid with glycols or ring-opening polymerization of lactones; (meth)acrylic acid ester polymers obtained by radical polymerization of monomers such as ethyl (meth)acrylate and butyl (meth)acrylate; vinyl polymers obtained by radical polymerization of monomers such as (meth)acrylic acid ester 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 skeletons may be contained in a block or random configuration. Among these polymers, polyoxyalkylene polymers and / or (meth)acrylic acid ester polymers are preferred because they are easy to handle and have a significant effect of extending the time during which lamination is possible.

[0218] 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 and 100 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 30 parts by mass or less, per 100 parts by mass of component (A).

[0219] (filler) Examples of fillers include inorganic fillers such as calcium carbonate, magnesium carbonate, titanium oxide, carbon black, fused silica, precipitated silica, diatomaceous earth, white clay, kaolin, clay, talc, wood flour, walnut shell powder, rice husk powder, silicic anhydride, quartz powder, aluminum powder, zinc powder, asbestos, glass fiber, carbon fiber, glass beads, alumina, glass balloons, shirasu balloons, silica balloons, calcium oxide, magnesium oxide, and silicon oxide, as well as organic fillers such as wood fillers such as pulp and cotton chips, powdered rubber, reclaimed rubber, fine powder of thermoplastic or thermosetting resin, and hollow bodies such as polyethylene. Only one type of filler may be added, or multiple types may be added in combination.

[0220] (diluent) By adding a diluent to the reactive hot melt adhesive of the present invention, physical properties such as viscosity can be adjusted. Because the adhesive is used at high temperatures (application, melting), it is preferable to use a solvent (diluent) with a boiling point of 150°C or higher, taking safety (fire, health) into consideration. 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.

[0221] Examples of diluents 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 and its derivatives; vinyl polymers obtained by polymerizing vinyl monomers using various methods; oils such as paraffinic process oil and naphthenic oil; synthetic waxes such as Fischer-Tropsch wax, polyethylene wax, polypropylene wax, and atactic polypropylene; and petroleum waxes such as paraffin wax and microcrystalline wax. These diluents can be used alone or in combination.

[0222] It is preferable to avoid adding solvents having a boiling point of 120°C or less, 150°C or less, or 200°C or less to the reactive hot melt adhesive according to the present invention.

[0223] (stabilizer) Examples of stabilizers include antioxidants, light stabilizers, and ultraviolet absorbers. The use of an antioxidant can improve the weather resistance and heat resistance of the cured product. Examples of antioxidants include hindered phenol, monophenol, bisphenol, and polyphenol compounds, with hindered phenol compounds being particularly preferred. The use of a light stabilizer can prevent photooxidative degradation of the cured product. Examples of light stabilizers include benzotriazole, hindered amine, and benzoate compounds, with hindered amine compounds being particularly preferred. The use of an ultraviolet absorber can improve the surface weather resistance of the cured product. Examples of ultraviolet absorbers include benzophenone, benzotriazole, salicylate, substituted tolyl, and metal chelate compounds, with benzotriazole compounds being particularly preferred. It is also preferable to use a phenol or hindered phenol antioxidant in combination with a hindered amine light stabilizer and a benzotriazole ultraviolet absorber.

[0224] (Flame retardant) Examples of the flame retardant include linear phosphazenes and cyclic phosphazenes described in JP-A No. 2002-519463, with phenoxyphosphazene being preferred.

[0225] Examples of flame retardants include organic halogen compounds such as decabromobisphenyl ether and tetrabromobisphenol; inorganic halogen compounds such as ammonium bromide; tertiary phosphines such as triarylphosphine, trialkylphosphine, bis(diarylphosphino)benzene and tris(diarylphosphino)benzene; organic metal phosphates such as aluminum tris(diethylphosphinate); 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, barium metaborate, hydroxoantimonate, zirconium oxide, zirconium hydroxide, molybdenum oxide, ammonium molybdate, zinc borate, ammonium borate, barium metaborate, talc, silicates, silicon oxide, tin oxide, and siloxane compounds.

[0226] <Content of component (A)> In the reactive hot melt adhesive of the present invention, component (A) is preferably contained in the hot melt adhesive at 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, from the viewpoint of the properties of the hot melt adhesive.

[0227] <Preparation method for moisture-curing hot melt adhesive> The reactive hot melt adhesive according to the present invention can be prepared as a one-component adhesive in which all of the components (e.g., component (A), component (B), component (C), component (D), component (E), and / or other additives) are mixed in advance and stored in a sealed container, and the adhesive is cured by moisture in the air after application. Alternatively, the adhesive can be prepared as a two-component adhesive in which, for example, a mixture of component (A), component (C), component (E), and / or other additives is mixed with a mixture of component (B) and component (D) before use.

[0228] There are no particular limitations on the method for preparing the reactive hot melt adhesive of the present invention. For example, conventional methods can be used, such as blending the above-mentioned components in a predetermined blending ratio and kneading them at room temperature or under heat using a mixer, roll, kneader, etc., or dissolving each component in a small amount of a predetermined solvent and mixing them.

[0229] 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, the coating properties and workability will be reduced, or a higher coating temperature will be required to ensure coating properties and workability. In such cases, the range of use will be limited, such as making it difficult to use the adhesive on substrates with low heat resistance.

[0230] <Application> The moisture-curable hot melt adhesive according to the present invention is excellent in drop impact resistance, waterproofing, flexibility, and shape retention after application, and therefore can be suitably used for bonding to various substrates including metals, resins, paper, wood, stone, and concrete. Specifically, it can be suitably used in construction, building materials, automobiles, electrical and electronic component applications (e.g., bonding optical components), and production lines for textiles, leather, clothing, bookbinding, and the like. It can also be suitably used in applications other than production lines, such as on-site construction at construction sites and DIY projects.

[0231] Examples of applications for bonding optical components include applications as sealants for mobile information terminals such as mobile phones and smartphones, information processing terminals such as personal computers and tablet terminals, game consoles, televisions, car navigation systems, cameras, speakers, head-mounted displays, etc. The moisture-curing hot melt adhesive according to the present invention may also be used as a sealant, coating agent, or potting agent.

[0232] <How to apply moisture-curing hot melt adhesive> The moisture-curable silylated polyurethane adhesive of the present invention can be applied using the same application methods as those used for various known reactive hot melt adhesives. For example, the application method may include the steps of 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 (application step), and bonding a second adherend to the first adherend so as to sandwich the adhesive therebetween (bonding step). Note that in the application step, the adhesive of the present invention may be applied not only to the first adherend but also to the bonding area of the second adherend.

[0233] Specifically, when bonding one substrate to another substrate using the moisture-curable hot melt adhesive according to the present invention, for example, the moisture-curable hot melt adhesive is heated and melted in the range of 50°C to 130°C, the molten adhesive is applied to one substrate, and then the other substrate is bonded onto the molten adhesive and moisture-cured. This allows for the production of a laminate in which one substrate and the other substrate are bonded together with the moisture-curable hot melt adhesive.

[0234] Examples of metal substrates include simple metals such as iron, nickel, chromium, aluminum, magnesium, copper, and lead; alloys obtained from the above simple metals such as stainless steel and brass; plated metals such as iron plated with a metal such as zinc, nickel, or chromium; and metals obtained by subjecting the above simple metals, alloys, or plated metals to chemical conversion treatments such as chromate treatment and phosphate treatment.

[0235] Examples of resin substrates include substrates made of 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 (polyether ether ketone), 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. The substrate may also be subjected to pretreatment such as corona treatment, plasma treatment, or primer treatment, as needed.

[0236] (Application method) Examples of methods for applying the moisture-curing hot melt adhesive to a substrate include methods using a roll coater, spray coater, T-tie coater, knife coater, comma coater, etc.; and methods for applying using a dispenser, inkjet printing, screen printing, offset printing, etc.

[0237] The latter application method, such as using a dispenser, allows for precise application of a small amount of moisture-curable hot melt adhesive to the desired location on the substrate, eliminating losses from processes such as punching. This method is particularly suitable for application with dispensers and other methods that handle compositions that cure easily at room temperature, as it offers excellent heat stability in a sealed heating tank (liquid transfer tank). This application method also allows for the moisture-curable hot melt adhesive to be applied continuously or intermittently to the substrate in a variety of shapes, including dots, lines, dashed lines, dot-and-dash lines, polygons such as triangles and squares, circles, ellipses, and curves.

[0238] The thickness of the adhesive layer using the moisture-curable hot melt adhesive can be set appropriately depending on the application it is used in. As an example, the thickness of the adhesive layer is in the range of about 10 μm to 5 mm.

[0239] The conditions for aging the film under 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.

[0240] The above method produces a laminate having multiple substrates and an adhesive layer made of an adhesive obtained by moisture-curing a moisture-curable hot melt adhesive. The adhesive layer can be peeled off from the laminate to recover the substrates by heating the laminate at a temperature in the range of 40°C to 150°C, which is preferred because the adhesive layer can be easily peeled off by hand.

[0241] <Effects of the embodiment> The moisture-curable hot melt adhesive of the present invention contains an alkoxysilyl group-containing urethane prepolymer (A) having a specific structure, and therefore can achieve both good build-up strength and a sufficiently long bonding time. Furthermore, because the reactive hot melt adhesive of the present invention has good build-up strength, it can be suitably used on adherends having curved surfaces, etc.

[0242] Furthermore, the moisture-curable hot melt adhesive of the present invention exhibits an appropriate viscosity at the application temperature, resulting in good application workability. Furthermore, the moisture-curable silylated polyurethane adhesive of the present invention is formulated so as to be substantially free of isocyanate groups, so that no free monomeric polyisocyanate is released upon heating, and substantially no polyurea is formed by reaction with moisture. This prevents swelling of the adhesive surface due to carbon dioxide release, and thus prevents a decrease in adhesive strength.

[0243] When one or both of the adherends are wood-based materials such as wood, plywood, or wood-based fiberboard, or moisture-permeable materials such as paper, the adhesive strength of a urethane-based reactive hot melt adhesive decreases over time. This tendency is particularly pronounced in humid atmospheres. On the other hand, the moisture-curing hot melt adhesive of the present invention does not decrease in adhesive strength over time even when used in humid atmospheres on adherends made of wood-based materials or moisture-permeable materials. Therefore, the reactive hot melt adhesive of the present invention is particularly useful when wood-based materials or moisture-permeable materials are used as adherends. [Example]

[0244] The present invention will be explained in more detail below with reference to examples. It should be noted that these examples are merely illustrative and should not be construed as limiting.

[0245] (Synthesis Example 1: Synthesis of methyl methacrylate polymer (a2-1) containing alkoxysilyl groups having hydroxyl groups) 70 g of methyl methacrylate, 30 g of 2-ethylhexyl methacrylate, 8 g of 3-methacryloxypropyltrimethoxysilane, 0.1 g of titanocene dichloride as a metal catalyst, and 40 g of ethyl acetate as an organic solvent were placed in a reaction vessel and heated to 80°C under a nitrogen atmosphere with stirring. Next, 0.85 g of mercaptoethanol was added, and the reaction was carried out for 16 hours while adjusting the temperature inside the reaction vessel by heating and / or cooling so that the temperature was maintained at 80°C. After the 16-hour reaction, the temperature of the reaction mixture was returned to room temperature, and the polymerization was terminated, yielding a hydroxyl-containing alkoxysilyl group-containing methyl methacrylate polymer (a2-1). The number-average molecular weight of component (a2-1) measured by gel permeation chromatography was 4,755, and the nonvolatile content was 66%.

[0246] (Measurement of number average molecular weight) The number average molecular weight was measured by gel permeation chromatography (GPC) under the following conditions: Specifically, the measurement object was measured by GPC under the following measurement conditions, and the molecular weight of the maximum frequency converted into standard polyethylene glycol was taken as the number average molecular weight.

[0247] The number average molecular weight can be measured, for example, using HLC-8220 (manufactured by Tosoh Corporation) under the following conditions using polystyrene as a standard substance. The same applies to the measurement of the number average molecular weight in the synthesis examples described later.

[0248] Columns used: G7000HXL x 1, GMHXL x 2, G2000HXL x 1 Solvent: THF Flow rate: 1.0ml / min Measurement temperature: 40℃

[0249] Synthesis Example 2: Synthesis of Alkoxysilyl Group-Containing Urethane Prepolymer (Polymer A) 100 g of polypropylene glycol (trade name: EDL-S101, polypropylene glycol ethylene oxide adduct (number average molecular weight 7,060, manufactured by Mitsui Chemicals SKC)) having a number average molecular weight of 7,000 was melt-mixed at 120 ° C for 1 hour and dehydrated under reduced pressure. Then, 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 Co., Ltd.) were added and reacted for 3 hours with stirring at 100 ° C under a nitrogen atmosphere to obtain a urethane prepolymer (a1-1). Then, 140.7 g (solids equivalent) of the hydroxyl-containing alkoxysilyl group-containing methyl methacrylate polymer (a2-1) having a number average molecular weight of 4,755 obtained in Synthesis Example 1 was added, and the mixture was stirred for 2 hours at 100 ° C. The reaction was completed when the -NCO absorption derived from the isocyanate group was confirmed to have disappeared by IR spectroscopy. After the reaction was completed, the solvent was distilled off to obtain Polymer A.

[0250] (IR spectrum measurement) The IR spectrum was measured using the following measuring device. FT-IR measurement device: JASCO Corporation FT-IR460Plus The conditions for measuring IR spectra in the synthesis examples described below are also the same.

[0251] Synthesis Example 3: Synthesis of Alkoxysilyl Group-Containing Urethane Prepolymer (Polymer B) 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 Corporation)) 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 Mills Co., Ltd.)) were melt-mixed at 120°C for 1 hour and dehydrated under reduced pressure. Then, diphenylmethane diisocyanate (MDI) (trade name: Millionate) was added. 10.6 g of methyl methacrylate (MT, manufactured by Tosoh Corporation) and 0.05 g of an amine catalyst (trade name: U-660M, manufactured by San-Apro Co., Ltd.) were added and reacted for 3 hours at 100°C with stirring under a nitrogen atmosphere to obtain a urethane prepolymer (a1-2). 160.8 g (solids content equivalent) of the hydroxyl-containing alkoxysilyl group-containing methyl methacrylate polymer (a2-1) with a number average molecular weight of 4,755 obtained in Synthesis Example 1 was then added, and the mixture was stirred for 2 hours at 100°C. The completion of the reaction was confirmed by IR spectroscopy, whereby the -NCO absorption derived from the isocyanate group had disappeared. After completion of the reaction, the solvent was distilled off to obtain Polymer B.

[0252] Synthesis Example 4: Synthesis of Alkoxysilyl Group-Containing Urethane Prepolymer (Polymer C) 100 g of polypropylene glycol having 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 Corporation)) and 56.0 g of crystalline polyester polyol having 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 Mills)) were melt-mixed at 120°C for 1 hour and dehydrated under reduced pressure. Then, 15.8 g of diphenylmethane diisocyanate (MDI) (trade name: Millionate MT, manufactured by Tosoh Corporation) and an amine catalyst (trade name: U-66 0.05 g of methyl methacrylate polymer (a2-1) containing hydroxyl groups and having a number average molecular weight of 4,755 (product number: KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the mixture, and the mixture was stirred at 100°C for 3 hours under a nitrogen atmosphere to obtain a urethane prepolymer (a1-3). 60.7 g (solids content equivalent) of the hydroxyl-containing alkoxysilyl group-containing methyl methacrylate polymer (a2-1) obtained in Synthesis Example 1 and 7.3 g of N-phenyl-3-aminopropyltrimethoxysilane (a2-2; anilinosilane) (product name: KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) were then added, and the mixture was stirred at 100°C for 2 hours. The completion of the reaction was confirmed by IR spectroscopy, whereby the -NCO absorption derived from the isocyanate group had disappeared. After the completion of the reaction, the solvent was distilled off to obtain Polymer C.

[0253] Synthesis Example 5: Synthesis of Alkoxysilyl Group-Containing Urethane Prepolymer (Polymer D) 100 g of polypropylene glycol having 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 Corporation)) and 56.0 g of crystalline polyester polyol having 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 Mills)) were melt-mixed at 120°C for 1 hour and dehydrated under reduced pressure. Then, 15.8 g of diphenylmethane diisocyanate (MDI) (trade name: Millionate MT, manufactured by Tosoh Corporation) and an amine catalyst (trade name: U-660M) were added. 0.05 g of methyl methacrylate polymer (manufactured by San-Apro Co., Ltd.) was added and reacted for 3 hours at 100°C with stirring under a nitrogen atmosphere to obtain urethane prepolymer (a1-3). 60.7 g (solids content equivalent) of hydroxyl-containing alkoxysilyl group-containing methyl methacrylate polymer (a2-1) 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 then added and stirred for 2 hours at 100°C. The completion of the reaction was confirmed by IR spectroscopy, whereby the -NCO absorption derived from the isocyanate group disappeared. After completion of the reaction, the solvent was distilled off to obtain polymer D.

[0254] Synthesis Example 6: Synthesis of Alkoxysilyl Group-Containing Urethane Prepolymer (Polymer E) 100 g of polypropylene glycol (trade name: EDL-S101, manufactured by Mitsui Chemicals SKC) with a number average molecular weight of 7,000 and polypropylene glycol ethylene oxide adduct (number average molecular weight 7,060, manufactured by Mitsui Chemicals SKC) was melt-mixed at 120°C for 1 hour and dehydrated under reduced pressure. Then, 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 Co., Ltd.) were added and reacted for 3 hours with stirring under a nitrogen atmosphere at 100°C to obtain urethane prepolymer (a1-1). 7.6 g of N-phenyl-3-aminopropyltrimethoxysilane (a2-2; anilinosilane) (trade name: KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) was then added, and the mixture was stirred for another 2 hours at 100°C to obtain polymer E. The completion of the reaction was confirmed by IR spectroscopy, where the -NCO absorption derived from the isocyanate group had disappeared.

[0255] Synthesis Example 7: Synthesis of Alkoxysilyl Group-Containing Urethane Prepolymer (Polymer F) 100.0 g of a crystalline polyester polyol with 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, product name: HS2H-200S, manufactured by Toyokuni Oil Mills)) was placed in a reaction vessel, melt-mixed at 120°C for 1 hour, and dehydrated under reduced pressure. Then, 25.7 g of diphenylmethane diisocyanate (MDI) (product name: Millionate MT, manufactured by Tosoh Corporation) and 0.05 g of an amine catalyst (product name: U-660M, manufactured by San-Apro Co., Ltd.) were added, and the mixture was allowed to react for 3 hours at 100°C with stirring under a nitrogen atmosphere to obtain urethane prepolymer (a1-4). Thereafter, 25.5 g of N-phenyl-3-aminopropyltrimethoxysilane (a2-2; anilinosilane) (trade name: KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was stirred for a further 2 hours at 100°C. This yielded Polymer F. The completion of the reaction was confirmed by IR spectroscopy, whereby the -NCO absorption derived from the isocyanate group had disappeared.

[0256] (Synthesis Example 8: Silane Compound) First, silane compound 2 was synthesized as a silane adhesion promoter by reacting two types of silane compounds with each other. Specifically, 1 mole of 3-glycidoxypropyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) and 1 mole of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed. Then, 1 mole of 3-glycidoxypropyltrimethoxysilane and 1 mole of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane were mixed and heated at 80°C for 3 days to allow the reaction to proceed. This resulted in silane compound 2 as a silane adhesion promoter. The molecular weight of silane compound 2 was 458.7 g / mol.

[0257] (Synthesis Example 9: Synthesis of Fluorinated Polymer) Using polypropylene glycol with a molecular weight of approximately 2,000 as an initiator, propylene oxide was reacted in the presence of a zinc hexacyanocobaltate-glyme complex catalyst to obtain polypropylene glycol. A polyoxyalkylene polymer having an allyl group at the end of the resulting polypropylene glycol was obtained according to the method of Synthesis Example 2 of WO2015-088021. To this polymer, methyldimethoxysilane, a silicon hydride compound, and an isopropanol solution of a platinum vinylsiloxane complex were added and reacted to obtain a polyoxyalkylene polymer (J) having methyldimethoxysilyl groups at the end. The molecular weight of the resulting polyoxyalkylene polymer having methyldimethoxysilyl groups at the end was measured by GPC, and the peak top molecular weight was 15,000 and the molecular weight distribution was 1.3. 1 H-NMR measurement (measured using Shimadzu NMR400 in CDCl3 solvent) revealed that there were 1.7 terminal methyldimethoxysilyl groups 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 terminal fluorosilyl groups (hereinafter referred to as "fluorinated polymer") was obtained according to the method of Synthesis Example 4 of WO2015-088021. The obtained fluorinated polymer 1The H-NMR spectrum showed that the peak (m, 0.63 ppm) corresponding to the silylmethylene (-CH2-Si) of the raw polymer disappeared, and a broad peak appeared on the low magnetic field side (0.7 ppm or higher).

[0258] (Synthesis Example 10: Synthesis of alkoxysilyl group-containing methyl methacrylate polymer) A flask equipped with a stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser was charged with 70 parts by weight of methyl methacrylate, 30 parts by weight of 2-ethylhexyl methacrylate, 12 parts by weight of γ-methacryloxypropyltrimethoxysilane, 0.1 parts by weight of titanocene dichloride as a metal catalyst, and 40 parts by weight of ethyl acetate as an organic solvent. The contents of the flask were heated to 80°C while nitrogen gas was introduced into the flask. Next, 8.5 parts by weight of 3-mercaptopropyltrimethoxysilane, which had been thoroughly purged with nitrogen gas, was added all at once to the stirred flask, and the contents were heated and cooled for 16 hours so that the temperature of the stirred flask contents remained at 80°C. After 16 hours of reaction, the temperature of the reactant was returned to room temperature, and polymerization was terminated, yielding an alkoxysilyl group-containing methyl methacrylate polymer having two silyl groups per molecule. The residual monomer content of the resulting ethyl acetate solution was measured using gas chromatography to determine the polymerization rate. As a result, a reaction product with a polymerization rate of 97% was obtained. The solid content of the resulting ethyl acetate solution was measured at 105°C and found to be 70.5%. The molecular weights of the resulting polymer measured by gel permeation chromatography (GPC) were weight average molecular weight (Mw) = 3800, number average molecular weight (Mn) = 1500, and polydispersity index = 2.4, and the viscosity at 25°C was 2.2 (Pa s).

[0259] The main ingredients in Synthesis Examples 2 to 7 are shown in Table 1.

[0260] [Table 1]

[0261] (Examples and Comparative Examples) For each of Examples 1 to 7 and Comparative Examples 1 to 4, component (A) or an alkoxysilyl group-containing methyl methacrylate polymer (Synthesis Example 10), component (B), component (C), component (D), component (E), and / or moisture absorbent were mixed in the proportions shown in Table 2, and the mixture was stirred and mixed in an environment of 120°C. Finally, the mixture was degassed under reduced pressure, and the one-component moisture-curable reactive hot melt adhesive for each of Examples 1 to 7 and Comparative Examples 1 to 4 was filled into a metal container. The resulting adhesives for Examples 1 to 7 and Comparative Examples 1 to 4 were evaluated as follows. The results are shown in Table 2. In Table 2, the unit of the amount of each compounded substance is "g," and the amount of polymer added in Synthesis Example 10 is expressed as a solids content value.

[0262] [Table 2]

[0263] Among the materials shown in Table 2, the details of the materials not shown in the synthesis examples are as follows. FTR6100 (styrene monomer / aliphatic monomer copolymer, product name: FTR6100, manufactured by Mitsui Chemicals) U-830 (tin catalyst; dioctyltin diversatate, trade name: Neostan U-830, manufactured by Nitto Kasei Co., Ltd.) SPUR1050MM (a silylated polyurethane having two trimethoxysilane terminal groups and a polyoxypropylene backbone, corresponding to silylated polyether urethane 1 (number average molecular weight [Mn] 16,400, polydispersity index [Mw / Mn] = approximately 1.7, amount of silyl functional groups = 0.122 milliequivalents / gram of polymer, viscosity: 35,000 mPa.s / 23°C [ASTM standard D1236], trade name: SPUR+1050MM, manufactured by Momentive) KBM3103C (decyltrimethoxysilane, product name: KBM3103C, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0264] (Evaluation method: viscosity at 120°C) The viscosity of the molten 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 Kogyo Co., Ltd., cone diameter: 14.5 mm, cone angle: 2.0°, rotation speed: 20 rpm).

[0265] (Evaluation method: shear bond strength) The one-component moisture-curing reactive hot melt adhesive according to Example 1 was heated to melt at 120°C and applied to a first aluminum plate (25mm x 75mm x 2mm, adhesive surface degreased with acetone) to a thickness of 100µm. Immediately after application, a second aluminum plate (25mm x 75mm x 2mm, adhesive surface degreased with acetone) was bonded to the first aluminum plate so that the area of the overlapping region was 25mm x 25mm from one end, sandwiching the adhesive, to prepare a test specimen. After curing the test specimen for a predetermined time in an environment of 23°C and 50% RH (curing time: 10 minutes after bonding and one week after bonding), the shear adhesive strength (N / mm) was measured at a tensile speed of 50mm / min in accordance with JIS K6850. 2 Here, the shear bond strength after 10 minutes of curing time from bonding is referred to as "initial strength" (in Table 2, shear bond strength after 10 minutes of curing (N / mm 2 ) (Al × Al)) and the shear bond strength after one week was recorded as the "ultimate strength (in Table 2, shear bond strength after one week curing (N / mm 2 ) (Al×Al)". The one-component moisture-curable reactive hot melt adhesives according to the other examples and comparative examples were also evaluated in the same manner.

[0266] (Evaluation method: bonding time) The one-component moisture-curing reactive hot melt adhesive according to Example 1 was heated and melted at 120°C and applied to a K-liner cardboard (250mm x 250mm x 7mm) to a thickness of 50µm. Test pieces (K-liner cardboard (25mm x 50mm x 7mm)) were bonded together with virtually no gaps at predetermined intervals (every 3 seconds until 1 minute, and every 15 seconds after 1 minute). After that, each test piece was bonded together in a 23°C, 50% RH environment and left to stand for 10 minutes. The test pieces were then peeled off by hand, and the time until no damage occurred in the bonded area was recorded as the bonding time (seconds). The one-component moisture-curing reactive hot melt adhesives according to other Examples and Comparative Examples were also evaluated in the same manner.

[0267] As can be seen from Table 2, it was confirmed that all of the adhesives according to the examples showed a good bonding time of 2 minutes or more, and also showed good rising strength.

[0268] On the other hand, as can be seen from Table 2, the adhesives according to the comparative examples all had an extremely short bonding time and did not have good rising strength.

[0269] Although the embodiments and examples of the present invention have been described above, the above-described embodiments and examples do not limit the scope of the invention as claimed. It should be noted that not all of the combinations of features described in the embodiments and examples are necessarily essential to the means for solving the problems of the invention, and that various modifications are possible without departing from the technical concept of the present invention.

Claims

1. A hot melt adhesive comprising an alkoxysilyl group-containing urethane prepolymer (A), The hot melt adhesive (A) is a compound obtained by reacting an alkoxysilyl group-containing methyl methacrylate polymer (a2-1) having a hydroxyl group, 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.

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

3. The hot melt adhesive according to claim 1, wherein (A) is a compound obtained by reacting the diisocyanate (i), the polyether polyol (ii), and the alkoxysilyl group-containing methyl methacrylate polymer (a2-1) having a hydroxyl group, and a polyester polyol and / or a polycarbonate polyol (ii-3).

4. 4. The hot melt adhesive according to claim 3, wherein the polyester polyol is a crystalline aliphatic polyester polyol.

5. 4. The hot melt adhesive according to claim 3, wherein the polycarbonate polyol is a crystalline aliphatic polycarbonate polyol.

6. The hot melt adhesive according to any one of claims 1 to 5, further comprising a silane-based adhesion promoter (B).

7. The hot melt adhesive according to claim 1, further comprising a modified resin (C).

8. 2. The hot melt adhesive according to claim 1, further comprising a crosslinking catalyst (D) containing an alkoxysilyl group.

9. 10. An article of manufacture comprising the hot melt adhesive of claim 1.

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