Adhesive set, adhesive composition and cured product thereof, and structure and method for manufacturing the same

Abstract

To provide an adhesive set capable of preparing an adhesive composition excellent in low-temperature rapid curability.SOLUTION: The adhesive set comprising a main agent and a curing agent is provided. The main agent contains a urethane prepolymer, and the curing agent contains a polyol. At least one of the main agent and the curing agent further contains a thiol compound. At least one of the main agent and the curing agent further contains a curing catalyst. The curing catalyst contains a tertiary amine.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an adhesive set, an adhesive composition and a cured product thereof, a structure, and a method for producing the same. [Background technology]

[0002] Steel sheets are commonly used for interior and exterior parts of automobiles, such as bodies, front doors, rear doors, tailgates, front bumpers, rear bumpers, and rocker moldings. However, in order to meet the recent demand for improved fuel efficiency, weight reduction is required. For this reason, plastic materials such as polypropylene are increasingly being used instead of steel sheets for interior and exterior parts of automobiles. However, because plastic materials such as polypropylene have lower strength than steel sheets, it is common to add talc, glass fillers, etc. to improve their strength.

[0003] Urethane adhesive compositions have been proposed as adhesives for joining plastic automobile parts, such as polypropylene. Known urethane adhesive compositions include one-component curing adhesives, known as moisture-curing adhesives, which cure when exposed to atmospheric moisture, and two-component curing adhesives, which are made by mixing an adhesive set consisting of a base compound and a curing agent. Two-component curing urethane adhesive compositions cure through a crosslinking reaction between the isocyanate group (NCO group) component contained in the base compound and the hydroxyl group (OH group) contained in the curing agent. Among these, two-component curing adhesives tend to be preferred from the standpoint of workability in the bonding process, as they can ensure sufficient usable time (pot life, the time until the paint begins to harden due to a chemical reaction in a multi-component paint) and can cure quickly.

[0004] For example, Patent Document 1 discloses a two-component curing urethane adhesive composition in which a base agent containing a urethane prepolymer and an isocyanate silane compound and a curing agent containing polybutadiene diol are mixed during operation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-077094 Summary of the Invention [Problem to be solved by the invention]

[0006] However, conventional two-component curing urethane adhesive compositions do not have sufficient curing properties at low temperatures (eg, 60° C.) in a short time (eg, 2 minutes), and there is still room for improvement.

[0007] A primary object of the present disclosure is to provide an adhesive set that makes it possible to prepare an adhesive composition that exhibits excellent low-temperature, rapid curing properties. [Means for solving the problem]

[0008] The present inventors conducted extensive research to solve the above-mentioned problems and discovered that in an adhesive set comprising a base agent containing a urethane prepolymer and a curing agent containing a polyol, the low-temperature, rapid curing properties can be improved by using a curing catalyst containing a tertiary amine and a thiol compound as at least one of the base agent and curing agent components, and have thus completed the invention of the present disclosure.

[0009] This disclosure includes the following [1] to [9]. [1] An adhesive set including a base agent and a curing agent, The base material contains a urethane prepolymer, the curing agent contains a polyol, At least one of the base agent and the curing agent further contains a thiol compound, At least one of the base agent and the curing agent further contains a curing catalyst, the curing catalyst comprises a tertiary amine; Adhesive set. [2] The thiol compound is a polyfunctional thiol compound. [1] The adhesive set described in [1]. [3] A composition containing a urethane prepolymer, a polyol, a thiol compound, and a curing catalyst, the curing catalyst comprises a tertiary amine; Adhesive composition. [4] The thiol compound is a polyfunctional thiol compound. [3] The adhesive composition according to [3]. [5] A cured product of the adhesive composition according to [3] or [4]. [6] a first substrate; a second substrate; an adhesive layer that bonds the first substrate and the second substrate to each other; Equipped with The adhesive layer contains a cured product of an adhesive composition containing the base agent and the curing agent in the adhesive set according to [1] or [2]. structure. [7] a first substrate; a second substrate; an adhesive layer that bonds the first substrate and the second substrate to each other; Equipped with The adhesive layer contains a cured product of the adhesive composition according to [6]. structure. [8] A method for producing the structure according to [6], a step of bonding the first substrate and the second substrate together via an adhesive composition containing the base agent and the curing agent, Method for manufacturing the structure. [9] A method for producing the structure according to [7], a step of bonding the first substrate and the second substrate together via the adhesive composition, Method for manufacturing the structure. [Effects of the Invention]

[0010] According to the present disclosure, an adhesive set is provided that can prepare an adhesive composition that exhibits excellent low-temperature, rapid curing properties. The present disclosure also provides a structure using such an adhesive set and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0011] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, in numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with a value shown in the examples. Furthermore, individually described upper and lower limits can be arbitrarily combined. In the expression "A to B," the numerical values ​​A and B at both ends are included as the lower and upper limits, respectively, in the numerical range. In this specification, for example, the expression "10 or more" means "10" and "a number greater than 10," and this also applies when the numerical values ​​are different. Furthermore, for example, the expression "10 or less" means "10" and "a number less than 10," and this also applies when the numerical values ​​are different.

[0012] Unless otherwise specified, the materials exemplified below may be used alone or in combination of two or more. When a composition contains multiple substances corresponding to each component, the amount used or content of each component means the total amount of the multiple substances present in the composition, unless otherwise specified.

[0013] [Adhesive set] An adhesive set according to one embodiment comprises (A) a base agent and (B) a curing agent. The (A) base agent contains (a) a urethane prepolymer and may contain (b) a polyisocyanate oligomer having a molecular weight of 1,000 or less. The (B) curing agent contains (c) a polyol. At least one of the (A) base agent and the (B) curing agent further contains (d) a thiol compound. At least one of the (A) base agent and the (B) curing agent further contains (e) a curing catalyst. The (e) curing catalyst contains (e-1) a tertiary amine. At least one of the (A) base agent and the (B) curing agent may further contain (f) carbon black, (g) a filler, (h) a plasticizer, etc. Each component is described below.

[0014] (a) Urethane prepolymer Component (a) is a reaction product of (a-1) a compound having two or more active hydrogen groups and (a-2) a polyisocyanate compound having two or more isocyanate groups. Component (a) is preferably a urethane prepolymer having an isocyanate group (as a terminal group). By reacting such component (a) so that the number of isocyanate groups is in excess, a urethane prepolymer having an isocyanate group as a terminal group can be obtained. Note that by using two or more types of component (a-1) and / or component (a-2), multiple components (a) may be present as the reaction product. Examples of active hydrogen groups include hydroxyl groups (OH groups), carboxyl groups (COOH groups), amino groups (NH groups), and mercapto groups (SH groups). The active hydrogen groups may be hydroxyl groups (OH groups). The component (a) may be the reaction product of the components (a-1) and (a-2) isolated and used, or may be the product obtained by reaction in the reaction system and used as is without isolation.

[0015] The component (a-1) may be a polyol, which is a compound having two or more hydroxyl groups (OH groups), such as a polyether polyol. The polyether polyol is not particularly limited, but examples thereof include polyethylene glycol (PEG), polypropylene glycol (PPG), ethylene oxide / propylene oxide copolymer, polytetramethylene ether glycol (PTMEG), and sorbitol-based polyols. One type of polyether polyol may be used alone, or two or more types may be used in combination. Among these, the polyether polyol may be, for example, polypropylene glycol (PPG).

[0016] The number average molecular weight of component (a-1) may be 20,000 or less, or may be 18,000 or less, 15,000 or less, or 12,000 or less. When the number average molecular weight of component (a-1) is 20,000 or less, the number of crosslinking points increases, and mechanical properties upon curing tend to improve. The number average molecular weight of component (a-1) is not particularly limited, but may be, for example, 1,000 or more.

[0017] In this specification, the term "number average molecular weight" is calculated using gel permeation chromatography (GPC) and a calibration curve of standard polystyrene. The GPC measurement conditions are, for example, as follows. Measurement equipment: ACQUITY UPLC APC system (Waters) Columns: APC XT-900, APC XT-200, APC XT-125, APC XT-45 (Waters) Carrier: tetrahydrofuran (THF) Detector: Differential refractive index detector Sample: 0.5% by mass THF solution Calibration curve: Polystyrene

[0018] Examples of the (a-2) component include aromatic polyisocyanates in which an isocyanate group is bonded to an aromatic hydrocarbon, alicyclic polyisocyanates in which an isocyanate group is bonded to an alicyclic hydrocarbon, and aliphatic polyisocyanates in which an isocyanate group is bonded to an aliphatic hydrocarbon. The (a-2) component may be used alone or in combination of two or more. Among these, the (a-2) component may be an aromatic polyisocyanate, such as diphenylmethane diisocyanate. Examples of diphenylmethane diisocyanate include 4,4'-diphenylmethane diisocyanate (4,4'-MDI) and 2,4'-diphenylmethane diisocyanate (2,4'-MDI).

[0019] When component (a-1) and component (a-2) are reacted to obtain component (a), a catalyst for forming a urethane prepolymer (a-3) may be used as needed. Component (a-3) may be, for example, a known catalyst that promotes a urethanization reaction or a urea-forming reaction. Examples of component (a-3) include tin-based catalysts and amine-based catalysts. Examples of tin-based catalysts include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin didecate, dioctyltin didecate, and tin 2-ethylhexanoate. Examples of amine catalysts include triethanolamine, trimethylamine, triethylamine, tripropylamine, tributylamine, trihexylamine, trioctylamine, triphenylamine, tribenzylamine, trinaphthylamine, triethylenediamine, bis(dimethylaminoethyl)ether, di(N,N-dimethylaminoethyl)amine, and 1-isobutyl-2-methylimidazole. The component (a-3) can be appropriately selected according to the desired curing rate.

[0020] The content of the (a-3) component can be adjusted appropriately depending on the types of the (a-1) component and the (a-2) component, etc. The content of the (a-3) component may be, for example, 0.001 to 5 mass%, 0.005 to 1 mass%, or 0.01 to 0.1 mass% based on the total amount of the (a-1) component and the (a-2) component.

[0021] The content of component (a) (the sum of components (a-1), (a-2), and (a-3)) may be 20 to 70 mass%, 25 to 65 mass%, or 30 to 60 mass%, based on the total amount of the main agent (A). When the content of component (a) is 20 mass% or more, based on the total amount of the main agent (A), a decrease in elongation during curing tends to be prevented, and when the content of component (a) is 70 mass% or less, based on the total amount of the main agent (A), a decrease in adhesive properties after curing (after curing) tends to be prevented. In one embodiment, the content of component (a) (the sum of components (a-1), (a-2), and (a-3)) may be 35 to 70 mass%, 40 to 65 mass%, or 45 to 60 mass%, based on the total amount of the main agent (A). In one embodiment, the content of the component (a) (the total of the components (a-1), (a-2), and (a-3)) may be 20 to 55 mass%, 25 to 50 mass%, or 30 to 45 mass%, based on the total amount of the main component (A).

[0022] (b) Polyisocyanate oligomers with a molecular weight of 1,000 or less When the (A) base agent mainly contains component (b), it tends to be possible to prepare an adhesive composition that exhibits excellent non-primer adhesion. The reason for this effect is not entirely clear, but it is thought that, for example, the adhesive composition can more easily conform to the irregularities of the substrate surface when a portion of the isocyanate group (NCO group) component contained in the base agent involved in crosslinking is a low-molecular-weight component. On the other hand, it is also thought that, for example, using a low-molecular-weight component as part of the NCO group component of the base agent brings the polarity of the adhesive composition closer to that of the substrate surface, improving the wettability of the adhesive composition and allowing the NCO group component, which may form a covalent bond with the substrate surface, to more easily approach the substrate surface.

[0023] The (b) component may be, for example, a polymer of a polyisocyanate having two or more isocyanate groups with a molecular weight of 1000 or less, or a polymer of a diisocyanate having two isocyanate groups with a molecular weight of 1000 or less. Examples of such polymers include a polymer of an aliphatic diisocyanate such as hexamethylene diisocyanate (HDI) and a polymer of an aromatic diisocyanate such as diphenylmethane diisocyanate (MDI). The aliphatic diisocyanate polymer may be, for example, a trimer of an aliphatic diisocyanate (isocyanurate, biuret, or adduct of trimethylolpropane (TMP)). Each of the (b) components may be used alone or in combination of two or more. The aliphatic diisocyanate polymer may be a trimer of HDI. The aromatic diisocyanate polymer may be a polymer of MDI. Component (b) may contain at least one of a polymer of an aliphatic diisocyanate having a molecular weight of 1,000 or less and a polymer of an aromatic diisocyanate having a molecular weight of 1,000 or less. However, since this provides even better non-primer adhesion, it is preferable that component (b) contain both a polymer of an aliphatic diisocyanate having a molecular weight of 1,000 or less and a polymer of an aromatic diisocyanate having a molecular weight of 1,000 or less.

[0024] Commercially available products of aliphatic diisocyanate polymers (HDI trimers) having a molecular weight of 1000 or less include, for example, Sumidur N3300 (trade name, manufactured by Sumika Bayer Urethane Co., Ltd.), Duranate 24A-100 (trade name, manufactured by Asahi Kasei Corporation), and Duranate E402-100 (trade name, manufactured by Asahi Kasei Corporation). Examples of aromatic diisocyanate polymers (MDI polymers) having a molecular weight of 1000 or less include Millionate MR-100 (trade name, manufactured by Tosoh Corporation) and Desmodur VKS20 (trade name, manufactured by Sumika Covestro Urethane Co., Ltd.).

[0025] The molecular weight of component (b) may be an average molecular weight (number average molecular weight). The molecular weight or average molecular weight of component (b) may be 1,000 or less, 900 or less, 800 or less, 700 or less, or 600 or less, or may be 100 or more, 200 or more, 300 or more, or 400 or more.

[0026] The content of component (b) may be 1 to 25 mass%, 3 to 20 mass%, or 5 to 15 mass%, based on the total amount of the main component (A). When the content of component (b) is 1 mass% or more, based on the total amount of the main component (A), non-primer adhesion improves and a decrease in adhesion durability between the substrate surface and the adhesive composition tends to be prevented. When the content of component (b) is 25 mass% or less, based on the total amount of the main component (A), sufficient flexibility tends to be imparted upon curing. In one embodiment, the content of component (b) may be 5 to 25 mass%, 7 to 20 mass%, or 10 to 15 mass%, based on the total amount of the main component (A). In one embodiment, the content of component (b) may be 1 to 15 mass%, 3 to 12 mass%, or 5 to 10 mass%, based on the total amount of the main component (A).

[0027] (c) Polyol Component (c) is not particularly limited as long as it is a polyol compound having two or more hydroxyl groups (OH groups), and may be, for example, a polyether polyol exemplified as component (a-1) above. Component (c) may have a number average molecular weight similar to that of component (a-1). Component (c) may be used alone or in combination with two or more. Component (c) may contain a compound having two hydroxyl groups (OH groups) and a compound having three or more hydroxyl groups (OH groups) because the crosslinking reaction is more likely to proceed.

[0028] The content of the (c) component may be 20 to 80 mass%, 25 to 75 mass%, or 30 to 70 mass%, based on the total amount of the (B) curing agent. When the content of the (c) component is 20 mass% or more, based on the total amount of the (B) curing agent, a decrease in flexibility of the adhesive composition during curing tends to be prevented, while when the content of the (c) component is 90 mass% or less, based on the total amount of the (B) curing agent, a decrease in strength during curing tends to be prevented. In one embodiment, the content of the (c) component may be 50 to 80 mass%, 55 to 75 mass%, or 50 to 70 mass%, based on the total amount of the (B) curing agent. In one embodiment, the content of the (c) component may be 20 to 60 mass%, 25 to 55 mass%, or 30 to 50 mass%, based on the total amount of the (B) curing agent.

[0029] (d) Thiol compounds At least one of the (A) base agent and the (B) curing agent further contains the (d) component. By combining the (d) component with the (e-1) component described below, the curing reaction of the adhesive composition tends to be accelerated.

[0030] Component (d) is not particularly limited as long as it is a compound having one or more thiol groups (SH groups). Component (d) may further have at least one group selected from the group consisting of a hydroxyl group (OH group) and a carboxyl group (COOH group) as a substituent. Component (d) may be a monofunctional thiol compound having one thiol group (SH group) or a polyfunctional thiol compound having two or more thiol groups (SH groups). Component (d) may also be a polyfunctional thiol compound. In this specification, monofunctional thiol compounds having two or more hydroxyl groups (OH groups) and polyfunctional thiol compounds having two or more hydroxyl groups (OH groups) are included in component (d) (thiol compound) but are not included in component (c) (polyol).

[0031] Examples of monofunctional thiol compounds include butanethiol, hexanethiol, octanethiol, 1-dodecanethiol, 4-methoxy-2-methyl-2-butanethiol, thiophenol, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 3-mercapto-1,2,4-triazole, 2-ethylhexyl-3-mercaptopropionate, n-octyl-3-mercaptopropionate, methoxybutyl-3-mercaptopropionate, and stearyl-3-mercaptopropionate.

[0032] Examples of monofunctional thiol compounds having a hydroxyl group include 1-mercapto-1,1-methanediol, 1-mercapto-1,1-ethanediol, 3-mercapto-1,2-propanediol (thioglycerin), 2-mercapto-1,2-propanediol, 2-mercapto-2-methyl-1,3-propanediol, 2-mercapto-2-ethyl-1,3-propanediol, 1-mercapto-2,2-propanediol, 2-mercaptoethyl-2-methyl-1,3-propanediol, 2-mercaptoethyl-2-ethyl-1,3-propanediol, and 4-hydroxythiophenol.

[0033] Examples of the monofunctional thiol compound having a carboxy group include 3-mercaptopropionic acid, 2-mercaptopropionic acid, and thioglycolic acid.

[0034] Examples of polyfunctional thiol compounds include trimethylolpropane tris(3-mercaptopropionate) (TMMP), pentaerythritol tetrakis(3-mercaptopropionate) (PEMP), dipentaerythritol hexakis(3-mercaptopropionate) (DPMP), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (TEMPIC), tris(3-mercaptopropyl)isocyanurate (TMPIC), ethylene glycol bis(thioglycolate) (EGTG), tetraethylene glycol bis(3-mercaptopropionate) (EGMP-4), trimethylolpropane tris(thioglycolate) (TMTG), pentaerythritol tetrakis(thioglycolate) (PE Examples of suitable thiol compounds include polyfunctional thiol compounds having an ester bond (-C(O)-O-) in the molecule, such as 1,4-bis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptobutyrate) (TPMB), and trimethylolethane tris(3-mercaptobutyrate) (TEMB); and polyfunctional thiol compounds not having an ester bond (-C(O)-O-) in the molecule (ester-free polyfunctional thiol compounds), such as 1,4-butanedithiol, 1,6-hexanedithiol, and 1,10-decanedithiol. Further, Thiokol LP (Toray Fine Chemicals Co., Ltd.) and the like can also be exemplified as a polyfunctional thiol compound.

[0035] Examples of polyfunctional thiol compounds having a hydroxyl group include polythiol QE-340M (Toray Fine Chemicals Co., Ltd.).

[0036] Examples of polyfunctional thiol compounds having a carboxy group include reaction products between a compound having one acid anhydride group in the molecule, such as succinic anhydride or trimellitic anhydride, and a polyfunctional thiol compound having a hydroxyl group; and reaction products between a compound having two or more acid anhydride groups in the molecule, such as pyromellitic anhydride, and a monofunctional thiol compound having a hydroxyl group or a polyfunctional thiol compound having a hydroxyl group.

[0037] The content of component (d) may be 0.05 to 10 mass%, 0.1 to 7 mass%, or 0.3 to 5 mass%, based on the total amount of the (A) base agent and the (B) curing agent. When the content of component (d) is 0.05 mass% or more, based on the total amount of the (A) base agent and the (B) curing agent, the curing reaction of the adhesive composition tends to be more sufficiently promoted. When the content of component (d) is 10 mass% or less, based on the total amount of the (A) base agent and the (B) curing agent, the usable life of the adhesive composition tends to be more sufficiently ensured.

[0038] The (d) component may be contained in the (B) curing agent. When the (B) curing agent contains the (d) component, the content of the (d) component may be 0.1 to 15 mass%, 0.5 to 10 mass%, or 0.5 to 5 mass%, based on the total amount of the (B) curing agent. When the content of the (d) component is 0.1 mass% or more, based on the total amount of the (B) curing agent, the curing reaction of the adhesive composition tends to be more sufficiently promoted. When the content of the (d) component is 15 mass% or less, based on the total amount of the (B) curing agent, the usable life of the adhesive composition tends to be more sufficiently ensured.

[0039] (e) Curing catalyst At least one of the (A) base agent and the (B) curing agent further contains the (e) component. The (e) component contains the (e-1) tertiary amine. By combining the (e-1) component with the above-mentioned (d) component, the curing reaction of the adhesive composition tends to be accelerated. In this specification, the term "tertiary amine" refers to a compound (NR) in which three hydrogen atoms of ammonia (NH) are substituted with hydrocarbon groups. 1 R 2 R 3 :R1 , R 2 , R 3 each independently represents a hydrocarbon group such as an alkyl group or an aryl group. However, compounds in which a nitrogen atom constituting an amine, together with a carbon atom constituting a hydrocarbon group, forms a nitrogen-containing aromatic heterocycle (e.g., an imidazole ring) are not included in the "tertiary amine" category. For example, alkyl-substituted imidazoles that form an imidazole ring as a nitrogen-containing aromatic heterocycle are not included in the "tertiary amine" category. Examples of component (e-1) include triethanolamine, trimethylamine, triethylamine, tripropylamine, tributylamine, trihexylamine, trioctylamine, triphenylamine, tribenzylamine, trinaphthylamine, triethylenediamine, bis(dimethylaminoethyl)ether, and di(N,N-dimethylaminoethyl)amine. Component (e-1) may be, for example, a trialkylamine or triethylamine.

[0040] The content of the (e-1) component may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, based on the total amount of the (e) component, and may be 100% by mass or less, 90% by mass or less, 80% by mass or less, 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, or 10% by mass or less.

[0041] Component (e) may contain (e-2) a curing catalyst other than a tertiary amine. Examples of component (e-2) include tin-based catalysts and amine-based catalysts other than component (e-1). Examples of tin-based catalysts include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin didecate, dioctyltin didecate, and tin 2-ethylhexanoate. Examples of amine-based catalysts other than component (e-1) include alkyl-substituted imidazoles such as 1-isobutyl-2-methylimidazole.

[0042] The content of the (e-2) component, based on the total amount of the (e) component, may be 0 mass% or more, 10 mass% or more, 20 mass% or more, 30 mass% or more, 40 mass% or more, 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, or 90 mass% or more, and may be 99 mass% or less, 97 mass% or less, or 95 mass% or less.

[0043] The content of the component (e) may be 0.1 to 10 mass %, 0.5 to 5 mass %, or 1 to 3 mass % based on the total amount of the base agent (A) and the curing agent (B).

[0044] The component (e) may be contained in the curing agent (B). The content of the component (e) may be 0.01 to 5 mass %, 0.05 to 3 mass %, or 0.1 to 2 mass % based on the total amount of the curing agent (B).

[0045] (f) Carbon black Component (f) may have an average particle size (D50: particle size at 50% of the volume particle size distribution curve) of 20 to 40 nm or 25 to 35 nm. By having the average particle size of component (f) within the above range, the viscosity of the adhesive composition and the dispersibility of component (f) can be adjusted to more appropriate ranges, which tends to further improve the workability and strength of the adhesive composition. The average particle size (D50) of carbon black can be measured by laser diffraction light scattering using, for example, a Beckman Coulter Model LS-230.

[0046] Commercially available products of component (f) include, for example, Monarch 460 (manufactured by Cabot Corporation), Asahi Carbon 70 (manufactured by Asahi Carbon Co., Ltd.), Seast 3 (manufactured by Tokai Carbon Co., Ltd.), Mitsubishi Carbon 32 (manufactured by Mitsubishi Chemical Corporation), and Nitelon 200 (manufactured by Shin-Nichika Carbon Co., Ltd.).

[0047] When at least one of the (A) base resin and the (B) curing agent contains the (f) component, the content of the (f) component may be 5 to 40% by mass or 10 to 30% by mass, based on the total amount of the (A) base resin and the (B) curing agent. When the content of the (f) component is 5% by mass or more, based on the total amount of the (A) base resin and the (B) curing agent, strength upon curing tends to be improved. When the content of the (f) component is 40% by mass or less, based on the total amount of the (A) base resin and the (B) curing agent, dispersibility is further improved, and strength upon curing tends to be maintained.

[0048] (g) Filler Examples of component (g) include kaolin, talc, silica, titanium oxide, calcium carbonate, bentonite, mica, sericite, glass flakes, glass fiber, graphite, magnesium hydroxide, aluminum hydroxide, antimony trioxide, barium sulfate, zinc borate, alumina, magnesia, wollastonite, xonotlite, whiskers, etc. Note that component (f) above is not included in component (g).

[0049] When at least one of the (A) base agent and the (B) curing agent contains the (g) component, the content of the (g) component may be 5 to 40 mass % or 10 to 30 mass % based on the total amount of the (A) base agent and the (B) curing agent.

[0050] (h) Plasticizers Examples of component (h) include phthalate ester compounds, alkylsulfonate ester compounds, adipate ester compounds, etc. Specific examples of phthalate ester compounds include dioctyl phthalate (DOP), dibutyl phthalate (DBP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), butyl benzyl phthalate (BBP), etc.

[0051] When at least one of the (A) base agent and the (B) curing agent contains the (h) component, the content of the (h) component may be 5 to 60 mass % or 10 to 50 mass % based on the total amount of the (A) base agent and the (B) curing agent.

[0052] At least one of the (A) base agent and the (B) curing agent may further contain, in addition to the above-mentioned components (f) to (h), an ultraviolet absorber, a dehydrating agent, a pigment, a dye, an antioxidant, an antioxidant, an antistatic agent, a flame retardant, an adhesion promoter, a dispersant, a solvent, etc.

[0053] When the (A) base resin and the (B) curing agent are mixed, the molar equivalent ratio (NCO / (OH+SH)) of the isocyanate groups (NCO) in the (A) base resin to the hydroxyl groups (OH) in the (B) curing agent and the thiol groups (SH) in at least one of the (A) base resin and the (B) curing agent may be, for example, 1.0 to 5.0. When the equivalent ratio (NCO / (OH+SH)) is 1.0 or higher, the proportion of unreacted polyol is reduced when the base resin and the curing agent are mixed, which tends to result in sufficient non-primer adhesion. When the equivalent ratio (NCO / (OH+SH)) is 5.0 or lower, the proportion of isocyanate and prepolymer is within an appropriate range when the base resin and the curing agent are mixed, which reduces the proportion of reaction with moisture in the air and tends to result in sufficient curing. The isocyanate groups in the (A) base agent are mainly derived from the (a) and (b) components, the hydroxyl groups in the (B) curing agent are mainly derived from the (c) component, and the thiol groups in at least one of the (A) base agent and the (B) curing agent are mainly derived from the (d) component.

[0054] The adhesive set of this embodiment can prepare an adhesive composition (two-component curing urethane adhesive composition) by mixing (A) the main component and (B) the curing agent. The temperature and time for mixing (A) the main component and (B) the curing agent may be, for example, 10 to 35°C and 1 to 60 minutes.

[0055] The method for mixing (A) the base resin and (B) the curing agent is not particularly limited, and may be, for example, a method in which they are mixed by hand application using a normal caulking gun, or a method in which they are mixed using a mechanical rotary mixer, static mixer, or the like in combination with a metering pump (e.g., a gear pump, a plunger pump, or the like) and a throttle valve for feeding the raw materials.

[0056] The prepared adhesive composition (two-component curing urethane adhesive composition) can be cured to form a cured product, which can act as an adhesive layer for bonding substrates together. The conditions for curing the adhesive composition (curing conditions) may be, for example, 10°C or higher, 30 to 60% RH (relative humidity), and 2 to 7 days.

[0057] [Structure and manufacturing method thereof] In one embodiment, the structure includes a first substrate, a second substrate, and an adhesive layer that bonds the first substrate and the second substrate together. The adhesive layer contains a cured product of an adhesive composition that includes the base agent and curing agent in the adhesive set. Examples of structures that can be used include vehicle back doors, trunk lids, windshields, and spoilers.

[0058] At least one of the first substrate and the second substrate may be a polypropylene (PP) substrate, or both the first substrate and the second substrate may be a polypropylene (PP) substrate. Examples of substrates other than polypropylene (PP) substrates include plastic substrates such as polyvinyl chloride, acrylonitrile / butadiene / styrene copolymer (ABS), polycarbonate (PC), polyamide (PA), poly(methyl methacrylate) (PMMA), polyester, epoxy resin, polyurethane (PUR), polyoxymethylene (POM), polyethylene (PE), ethylene / propylene copolymer (EPM), and ethylene / propylene / diene polymer (EPDM); fiber-reinforced plastic substrates such as carbon fiber reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP); and resin compound substrates such as sheet molding compound (SMC). When the structure is a vehicle back door, the first substrate may be an inner panel made of a polypropylene substrate, and the second substrate may be an outer panel made of a substrate other than a propylene substrate.

[0059] In one embodiment, a method for manufacturing a structure includes bonding a first substrate to a second substrate via an adhesive composition containing a base agent and a curing agent. The temperature and time for mixing the base agent (A) and the curing agent (B) in the adhesive set, and the conditions for curing the adhesive composition are the same as those described above. [Example]

[0060] The present disclosure will be described in more detail below with reference to examples, although the present disclosure is not limited to these examples.

[0061] [Preparation of intermediate product of main ingredient] A kneading vessel equipped with a stirrer, a nitrogen inlet tube, a vacuum pump, and a heating / cooling device was charged with 53.6 parts by mass of Preminol 3012 (a polyether polyol (a polymer of propylene glycol using glycerin as an initiator), manufactured by AGC Inc., number average molecular weight: 12,000, number of hydroxyl groups: 3) and 29.0 parts by mass of DINP (diisononyl phthalate), and the mixture was stirred at room temperature (25°C) for 60 minutes. Next, the kneading vessel was heated until the contents reached 100°C, and the pressure inside the kneading vessel was reduced to 2.7 kPa (20 mmHg) using a vacuum pump, and the contents were stirred for 1 hour. The contents were then cooled to 40°C, and 5.4 parts by mass of Millionate MT (4,4'-diphenylmethane diisocyanate, manufactured by Tosoh Corporation, NCO content: 33.6%) and 0.008 parts by mass of Dabco T-9 (tin-based catalyst, stannous octoate (2-ethylhexanoate tin), manufactured by Air Products & Chemicals Co.) were added to the kneading vessel. Nitrogen was then introduced, and the kneading vessel was heated to 70°C and stirred for 1 hour. The contents were then cooled to 40°C, and 5.0 parts by mass of Sumidur N3300 (an isocyanurate of hexamethylene diisocyanate (HDI), manufactured by Sumika Bayer Urethane Co., Ltd., molecular weight: 504.6) was added and stirred for 30 minutes. The viscous material obtained through the above process was used as the main component intermediate. The viscous material is presumed to contain a urethane prepolymer, which is a reaction product of Preminol 3012 and Millionate MT.

[0062] [Preparation of main agent] To the above-mentioned main component intermediate, 7.0 parts by mass of Millionate MR-100 (aromatic polyfunctional isocyanate (polymethylene polyphenyl polyisocyanate (polymeric MDI)), manufactured by Tosoh Corporation, NCO content: 31.0%, average molecular weight: 450) was added, and the mixture was stirred for 10 minutes to obtain main component (A-1).

[0063] [Preparation of hardener] A kneading vessel equipped with a stirrer, nitrogen inlet tube, vacuum pump, and heating / cooling device was charged with (c) polyol, (d) thiol compound, and (h) plasticizer of the types shown in Table 1 in the amounts shown in Table 1 (unit: parts by mass), and stirred at room temperature (25°C) for 30 minutes. The kneading vessel was then heated to 100°C, and the pressure inside the kneading vessel was reduced to 2.7 kPa (20 mmHg) using a vacuum pump, and the contents were stirred for 1 hour. The contents were then cooled to 40°C, and (e) curing catalyst of the types shown in Table 1 was added in the amounts shown in Table 1 (unit: parts by mass), and the mixture was stirred for 30 minutes. In this way, curing agents (B-1) to (B-9) were obtained as viscous substances.

[0064] [Table 1]

[0065] The symbols in Table 1 represent the following: (c) Polyol (c-1) Preminol 5005 (polypropylene glycol, manufactured by AGC Corporation, number average molecular weight: 5000, number of hydroxyl groups: 2) (c-2) Exenol 2020 (polypropylene glycol, manufactured by AGC Corporation, number average molecular weight: 2000, number of hydroxyl groups: 2) (c-3) EDP-1100 (ethylenediamine propylene oxide modified product, manufactured by ADEKA Corporation, number of hydroxyl groups: 4) (d) Thiol compounds (d-1) QE-340M (trithiol with polyether chain, Toray Fine Chemicals Co., Ltd., number of thiol groups: 3, number of hydroxyl groups: 3) (d-2) TMMP-LV (trimethylolpropane tris(3-mercaptopropionate), manufactured by SC Organic Chemical Co., Ltd., number of thiol groups: 3) (d-3) PEMP-LV (pentaerythritol tetrakis(3-mercaptopropionate), manufactured by SC Organic Chemical Co., Ltd., number of thiol groups: 4) (e) Curing catalyst (e-1) Tertiary amine (e-1-1) Triethylamine (e-2) Curing catalysts other than tertiary amines (e-2-1) Kao Raiser No. 120 (1-isobutyl-2-methylimidazole, manufactured by Kao Corporation) (h) Plasticizers (h-1) DINP (diisononyl phthalate)

[0066] [Preparing adhesive sets] Example 1 The combination of the main agent (A-1) and the curing agent (B-1) was used as the adhesive set of Example 1.

[0067] Example 2 The combination of the main agent (A-1) and the curing agent (B-2) was used as the adhesive set of Example 2.

[0068] Example 3 The combination of the main agent (A-1) and the curing agent (B-3) was used as the adhesive set of Example 3.

[0069] Example 4 The combination of the main agent (A-1) and the curing agent (B-4) was used as the adhesive set of Example 4.

[0070] Example 5 The combination of the main agent (A-1) and the curing agent (B-5) was used as the adhesive set of Example 5.

[0071] (Comparative Example 1) The combination of the main agent (A-1) and the curing agent (B-6) was used as the adhesive set of Comparative Example 1.

[0072] (Comparative Example 2) The combination of the main agent (A-1) and the curing agent (B-7) was used as the adhesive set of Comparative Example 2.

[0073] (Comparative Example 3) The combination of the main agent (A-1) and the curing agent (B-8) was used as the adhesive set of Comparative Example 3.

[0074] Comparative Example 4 The combination of the main agent (A-1) and the curing agent (B-9) was used as the adhesive set of Comparative Example 4.

[0075] [Evaluation test] <Evaluation of storage stability> The base resins and curing agents in the Examples and Comparative Examples were each stored for one month in a thermostatic chamber at 40° C. After storage, the base resins and curing agents were observed, and no precipitates were observed, indicating good storage stability.

[0076] <Pot life evaluation> The base agent and curing agent in each of the examples and comparative examples were mixed at room temperature (25°C) in a ratio of 1:2 (by mass) of base agent to curing agent, and stirred for 1 minute using a stirring rod. The resulting mixture (adhesive composition) was then observed over time, and the time until the mixture suddenly thickened and could no longer be stirred using a stirring rod was measured and evaluated as the pot life. A pot life of 3 minutes or more was rated "A," and a pot life of less than 3 minutes was rated "B." The results are shown in Tables 2 and 3.

[0077] <Evaluation of low-temperature fast curing properties> The base agent and curing agent in the examples and comparative examples were mixed at room temperature (25°C) in a ratio of 1:2 (by mass), stirred with a stirring rod for 1 minute, and allowed to stand for 3 minutes. The mixture (adhesive composition) obtained after stirring was then heated to 60°C over 1 minute and then maintained at 60°C for 2 minutes to obtain a cured adhesive composition as a measurement sample. The measurement sample was then measured using a rotational rheometer (Anton Paar, product name: MCR301, measurement jig: glass plate and 12 mm diameter aluminum plate) under conditions of a frequency of 1 Hz, a measurement temperature of 25°C, and a jig distance of 50 μm. The results are shown in Tables 2 and 3.

[0078] [Table 2]

[0079] [Table 3]

[0080] As shown in Tables 2 and 3, in the examples in which a tertiary amine was used as the curing agent component and a thiol compound was used as at least one of the main component and curing agent components, the cured product of the adhesive composition cured under specified conditions had a sufficient storage modulus in a short time, compared to the comparative examples in which this was not used. These results confirmed that the adhesive set of the present disclosure can prepare an adhesive composition that is excellent in low-temperature fast curing properties.

Claims

1. An adhesive set including a base agent and a curing agent, The base material contains a urethane prepolymer, the curing agent contains a polyol, At least one of the base agent and the curing agent further contains a thiol compound, At least one of the base agent and the curing agent further contains a curing catalyst, the curing catalyst comprises a tertiary amine; Adhesive set.

2. The thiol compound is a polyfunctional thiol compound. The adhesive set according to claim 1 .

3. The composition contains a urethane prepolymer, a polyol, a thiol compound, and a curing catalyst, the curing catalyst comprises a tertiary amine; Adhesive composition.

4. The thiol compound is a polyfunctional thiol compound. The adhesive composition according to claim 3.

5. A cured product of the adhesive composition according to claim 3 or 4.

6. a first substrate; a second substrate; and an adhesive layer that bonds the first substrate and the second substrate to each other; Equipped with The adhesive layer contains a cured product of an adhesive composition comprising the main agent and the curing agent in the adhesive set according to claim 1 or 2. structure.

7. a first substrate; a second substrate; and an adhesive layer that bonds the first substrate and the second substrate to each other; Equipped with The adhesive layer contains a cured product of the adhesive composition according to claim 6. structure.

8. A method for manufacturing the structure according to claim 6, comprising the steps of: a step of bonding the first substrate and the second substrate together via an adhesive composition containing the base agent and the curing agent, Method for manufacturing the structure.

9. A method for manufacturing the structure according to claim 7, comprising: a step of bonding the first substrate and the second substrate together via the adhesive composition, Method for manufacturing the structure.

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