Urethane-based adhesive composition

Abstract

An object of the present application is to provide a urethane-based adhesive composition which exhibits excellent rubber properties. The urethane-based adhesive composition of the present application is a urethane-based adhesive composition containing a urethane prepolymer (A) having an isocyanate group at a terminal, and a compound (B) represented by the following formula (1). In formula (1), R represents a hydrogen atom or an alkyl group, and n represents an integer of 6 or more.

Description

Technical Field

[0001] This invention relates to urethane adhesive compositions. Background Technology

[0002] Previously, urethane adhesive compositions have been proposed as sealants and adhesives for automotive, construction, and structural applications (e.g., Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2020 / 158289 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Recently, with increasing demands for performance and safety in various fields, there is a growing need to improve the cured rubber properties (hereinafter referred to as "rubber properties") of urethane adhesive compositions. In particular, there is a need to improve the cured strength (breaking strength) and elongation (elongation at break). Furthermore, it is necessary to maintain excellent rubber properties even after exposure to high temperatures.

[0008] In this context, the inventors of this application, referring to Patent Document 1, formulated a carbamate adhesive composition and studied its rubber properties, and confirmed that further improvements are needed considering the increasing requirements in the future.

[0009] Therefore, in view of the above-mentioned circumstances, the present invention aims to provide a urethane adhesive composition exhibiting excellent rubber properties.

[0010] Methods for solving problems

[0011] The inventors of this application conducted in-depth research on the above-mentioned problems and found that by mixing specific cashew phenol epoxide adducts, the above-mentioned problems can be solved, thereby completing the present invention.

[0012] That is, the inventors of this application have discovered that the above-mentioned problems can be solved by the following configuration.

[0013] (1) A urethane adhesive composition comprising a urethane prepolymer (A) having isocyanate groups at the ends, and a compound (B) represented by formula (1) described below.

[0014] (2) According to the carbamate adhesive composition described in (1) above, the content of the above compound (B) is 0.01 to 10% by mass relative to the total mass of the carbamate adhesive composition.

[0015] (3) According to the urethane adhesive composition described in (1) or (2) above, the urethane prepolymer (A) is obtained by mixing and reacting a polyether polyol with a number average molecular weight of 500 to 20,000 with an aromatic polyisocyanate in such a ratio that the isocyanate group of the aromatic polyisocyanate is 1.5 to 2.5 moles relative to the hydroxyl group of the polyether polyol.

[0016] (4) The carbamate adhesive composition according to any one of (1) to (3) above further contains carbon black or calcium carbonate.

[0017] (5) The urethane adhesive composition according to any one of (1) to (4) above further contains an isocyanate modifier.

[0018] Invention Effects

[0019] As shown below, according to the present invention, urethane adhesive compositions exhibiting excellent rubber properties can be provided. Detailed Implementation

[0020] The urethane adhesive composition of the present invention will be described below.

[0021] It should be noted that, in this specification, the numerical range represented by “~” refers to the range of values ​​recorded before and after “~” as the lower and upper limits.

[0022] Furthermore, the components contained in the carbamate adhesive composition of the present invention can be used individually or in combination of two or more. Here, when two or more components are used in combination, the term "content" for that component, unless otherwise specified, refers to the total content.

[0023] In addition, the excellent adhesion and the excellent physical properties of the cured rubber (strength, elongation, hardness) are also referred to as "the excellent effects of the present invention".

[0024] In addition, exposure to high-temperature environments (e.g., standing at 90°C for 2 weeks) is also referred to as "heat-resistant".

[0025] The urethane adhesive composition of the present invention (hereinafter also referred to as "the composition of the present invention") is as follows:

[0026] A urethane adhesive composition containing a urethane prepolymer (A) having an isocyanate group at the end and a compound (B) represented by formula (1) described later.

[0027] Because the composition of the present invention has such a structure, it is believed that the aforementioned problems of the present invention can be solved. Although the reason is not clear, the reason for the high elongation can be considered as follows: the OH group of compound (B) reacts with the isocyanate group of the urethane prepolymer, thereby slightly reducing the crosslinking density.

[0028] The compositions of the present invention can be any combination of a one-component urethane adhesive composition without a curing agent, or a two-component urethane adhesive composition comprising a base containing urethane prepolymer (A) and a curing agent. However, for reasons of superiority such as the effects of the present invention, a two-component urethane adhesive composition is preferred. When the composition of the present invention is a two-component urethane adhesive composition, compound (B) may be included in either the base or the curing agent. However, for reasons of superiority such as the effects of the present invention, compound (B) is preferably included in the base.

[0029] [Carbamate Prepolymer (A)]

[0030] The urethane prepolymer (A) is a urethane prepolymer with isocyanate groups at the ends.

[0031] A preferred embodiment is a urethane prepolymer (A) containing two or more isocyanate groups at the end of a single molecule.

[0032] As the urethane prepolymer (A), conventionally known urethane prepolymers can be used.

[0033] For reasons of superior effects of the present invention, the urethane prepolymer (A) is preferably a urethane prepolymer obtained by reacting a polyisocyanate with a compound having two or more active hydrogen groups in one molecule (hereinafter also referred to as "active hydrogen compound") in such a way that the isocyanate groups become excessive relative to the active hydrogen groups.

[0034] In this invention, "containing active hydrogen group" refers to a group that contains active hydrogen. Examples of active hydrogen groups include hydroxyl, amino, and imino groups.

[0035] [Polyisocyanates]

[0036] The polyisocyanate used in the manufacture of urethane prepolymer (A) is not particularly limited as long as it has more than two isocyanate groups in one molecule.

[0037] Examples of polyisocyanates include, for example, toluene diisocyanate (TDI, e.g., 2,4-toluene diisocyanate, 2,6-toluene diisocyanate), diphenylmethane diisocyanate (MDI, e.g., 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, diphenylene diisocyanate (XDI), tetramethylphenylene diisocyanate (TMXDI), and dimethylbiphenyl diisocyanate. Aromatic polyisocyanates such as TODI, 1,5-naphthalene diisocyanate (NDI), and triphenylmethane triisocyanate; hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornene diisocyanate (NBDI), transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis(isocyanatomethyl)cyclohexane (H6XDI), and dicyclohexylmethane diisocyanate (H 12 Aliphatic and / or alicyclic polyisocyanates such as MDI; their carbodiimide-modified polyisocyanates, isocyanurate-modified polyisocyanates, and urethane-modified polyisocyanates.

[0038] For reasons of superior performance and other advantages of the present invention, the polyisocyanate is preferably an aromatic polyisocyanate, and more preferably MDI.

[0039] Polyisocyanates can be used individually or in combination of two or more.

[0040] [Active hydrogen compounds]

[0041] There are no particular limitations on the compounds (active hydrogen compounds) having two or more active hydrogen groups per molecule used in the manufacture of urethane prepolymer (A). Examples of active hydrogen groups include, for example, hydroxyl (OH group), amino, and imino groups.

[0042] Suitable examples of the aforementioned active hydrogen compounds include, for instance, polyols having two or more hydroxyl groups (OH groups) in one molecule, and polyamine compounds having two or more amino and / or imino groups in one molecule. Among these, polyols are preferred.

[0043] The aforementioned polyols are any compounds having two or more OH groups, and there is no particular limitation. Specific examples of polyols include polyether polyols; polyester polyols; (meth)acrylic acid polyols; polybutadiene polyols, hydrogenated polybutadiene polyols; low molecular weight polyols; and mixtures thereof. Among these, polyether polyols are preferred for reasons of superior effects of the present invention.

[0044] Polyether polyols are any compounds that have a polyether group as the main chain and two or more hydroxyl groups; there are no particular restrictions. A polyether group is a group with two or more ether bonds. For example, a polyether polyol may have a total of two or more structural units -R. a -OR b - group. Here, in the above structural unit, R a and R b Each can be represented independently by a hydrocarbon group. There are no particular restrictions on the hydrocarbon group. Examples include straight-chain alkylene groups with 1 to 10 carbon atoms.

[0045] Examples of polyether polyols include, for example, polyoxyethylene glycol (polyethylene glycol), polyoxypropylene glycol (polypropylene glycol: PPG), polyoxypropylene triol, polyols derived from ethylene oxide / propylene oxide copolymers, polytetramethylene ether glycol (PTMEG), polytetraethylene glycol, and sorbitol-based polyols.

[0046] From the viewpoint of excellent compatibility with polyisocyanates, polyether polyols are preferably polypropylene glycol or polyoxypropylene triol.

[0047] For reasons of superior performance of the present invention, the number average molecular weight (Mw) of the polyether polyol is preferably 500 to 20,000.

[0048] It should be noted that, in this specification, the number-average molecular weight of polyols is a value obtained from the hydroxyl value and the average number of functional groups, specifically calculated as (56,100 / hydroxyl value) × average number of functional groups.

[0049] Here, the hydroxyl value is the hydroxyl value recorded in JIS K 1557-1:2007, which is the number of mg of potassium hydroxide equivalent to 1 g of hydroxyl groups in the sample. Additionally, the average number of functional groups is the average number of hydroxyl groups present in one molecule of polyol.

[0050] Active hydrogen compounds can be used individually or in combination of two or more.

[0051] [Appropriate method]

[0052] For reasons of superior performance of the present invention, the urethane prepolymer (A) is preferably a urethane prepolymer obtained by reacting a polyether polyol with an aromatic polyisocyanate.

[0053] When the urethane prepolymer (A) is a urethane prepolymer obtained by reacting a polyisocyanate with a polyol, for reasons of superiority such as the effect of the present invention, the molar ratio (NCO / OH) of the isocyanate group of the polyisocyanate to the hydroxyl group of the polyol is preferably 1.5 to 2.5.

[0054] For reasons of superior performance and other advantages of the present invention, the urethane prepolymer (A) is preferably:

[0055] A urethane prepolymer is obtained by mixing and reacting a polyether polyol with a number average molecular weight of 500 to 20,000 with an aromatic polyisocyanate in such a ratio that the isocyanate group of the aromatic polyisocyanate is 1.5 to 2.5 moles to the hydroxyl group of the polyether polyol (i.e., NCO / OH = 1.5 to 2.5).

[0056] 〔content〕

[0057] In the composition of the present invention, for reasons of superior effect of the present invention, the content of urethane prepolymer (A) relative to the total mass of the composition is preferably 10 to 95% by mass, more preferably 20 to 60% by mass.

[0058] [Compound (B)]

[0059] Compound (B) is the compound represented by the following formula (1).

[0060]

[0061] In formula (1), R represents a hydrogen atom or an alkyl group, and n represents an integer greater than 6.

[0062] For reasons of superior effects of the present invention, R is preferably a hydrogen atom.

[0063] When R is an alkyl group, for reasons of superior effect of the present invention, R is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group.

[0064] For reasons of superior effects of the present invention, n is preferably an integer from 6 to 20, more preferably an integer from 8 to 18, and even more preferably an integer from 10 to 16.

[0065] [Synthesis Method]

[0066] There are no particular restrictions on the synthesis method of compound (B), for example, the reaction of ethylene oxide with cashew phenol.

[0067] It should be noted that products containing compound (B) include, for example, GX-5170, GX-5167, and GX-5166 manufactured by Cardolite.

[0068] 〔content〕

[0069] In the composition of the present invention, the content of compound (B) is not particularly limited, but for reasons of superior effect of the present invention, it is preferably 0.01 to 10% by mass relative to the total mass of the composition, more preferably 0.1 to 1% by mass.

[0070] Furthermore, for reasons of superior effects of the present invention, the content of compound (B) relative to the content of the above-mentioned urethane prepolymer (A) is preferably 0.01 to 30% by mass, more preferably 0.1 to 10% by mass, and even more preferably 0.2 to 1% by mass.

[0071] Furthermore, for reasons of superior effects of the present invention, the content of compound (B) relative to the content of the isocyanurate modifier described later is preferably 1 to 1000% by mass, more preferably 2 to 100% by mass, even more preferably 3 to 30% by mass, and particularly preferably 10 to 20% by mass.

[0072] [Curing agent]

[0073] As described above, for reasons of superior effects and other considerations, the composition of the present invention is preferably a two-component urethane adhesive composition comprising a main agent containing urethane prepolymer (A) and a curing agent.

[0074] The curing agent described above contains a compound having two or more active hydrogen groups in one molecule (an active hydrogen compound). Specific examples and suitable methods of active hydrogen compounds are the same as those described above.

[0075] 〔content〕

[0076] In the composition of the present invention, for reasons of superior effect of the present invention, the content of active hydrogen-containing groups of the active hydrogen compound in the curing agent is preferably 1 to 100 mol%, more preferably 5 to 50 mol%, relative to the content of isocyanate groups in the above-mentioned urethane prepolymer (A).

[0077] [Mixing ratio]

[0078] When the composition of the present invention is a two-component urethane adhesive composition, for reasons of superior effect of the present invention, the mass ratio of curing agent to main agent (curing agent / main agent) is preferably 0.01 to 1, more preferably 0.05 to 0.2.

[0079] Furthermore, for reasons of superior effects of the present invention, the mass ratio of the active hydrogen compound in the curing agent to the urethane prepolymer (A) is preferably 0.01 to 1, more preferably 0.05 to 0.2.

[0080] [Other ingredients]

[0081] The compositions of the present invention may contain other components besides those described above.

[0082] In the case of a two-component formulation, it is appropriate to choose whether to add other components to either the main agent or the curing agent.

[0083] Other components may include, for example, fillers (e.g., carbon black, calcium carbonate), isocyanate modifiers (e.g., isocyanurate, urea-formate, biuret), catalysts (curing catalysts), plasticizers, anti-aging agents, antioxidants, silane coupling agents, pigments (dyes), tackifiers, terpene compounds such as terpineol, thixotropic agents, UV absorbers, flame retardants, surfactants (including leveling agents), dispersants, dehydrating agents, antistatic agents, and various other additives.

[0084] It should be noted that the above-mentioned filler can be surface-treated using at least one treatment agent selected from the group consisting of fatty acids, resin acids, carbamate compounds and fatty acid esters.

[0085] In addition, when the composition of the present invention is a two-component form, it is appropriate to choose whether to add any of the above-mentioned components to either the main agent or the curing agent.

[0086] For reasons of superior effects, the compositions of the present invention are preferably free of terpene compounds.

[0087] [Modified isocyanates]

[0088] For reasons of superior effects, the compositions of the present invention preferably contain isocyanate modifiers.

[0089] For reasons of superior effects of the present invention, the modified isocyanate preferably contains at least one of the following: isocyanurate ester (ureate ester), ureocarbamate ester, and biuret ester of isocyanate; more preferably, it contains isocyanurate ester (ureate ester).

[0090] Specific examples of isocyanates constituting modified isocyanates are the same as those of the polyisocyanates described above.

[0091] For reasons of superior effects of the present invention, the isocyanate constituting the modified isocyanate is preferably an aliphatic isocyanate, and more preferably HDI.

[0092] <Content>

[0093] In the composition of the present invention, the content of the isocyanate modifier is not particularly limited, but for reasons of superior effect of the present invention, it is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, relative to the total mass of the composition.

[0094] In the composition of the present invention, the content of the isocyanate modifier is not particularly limited, but for reasons of superior effect of the present invention, the content of the urethane prepolymer (A) described above is preferably 1 to 20% by mass, more preferably 2 to 10% by mass.

[0095] [Silane coupling agent]

[0096] For reasons of superior effects, the composition of the present invention preferably contains a silane coupling agent.

[0097] <Content>

[0098] In the composition of the present invention, the content of the silane coupling agent is not particularly limited, but for reasons of superior effect of the present invention, the content of the urethane prepolymer (A) described above is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass.

[0099] [Carbon black]

[0100] For reasons of superior effects, the composition of the present invention preferably contains carbon black.

[0101] There are no particular restrictions on carbon black. Examples include SAF (Super Abrasion Furnace), ISAF (Intermediate Super Abrasion Furnace), HAF (High Abrasion Furnace), FEF (Fast Extruding Furnace), GPF (General Purpose Furnace), SRF (Semi-Reinforcing Furnace), FT (Fine Thermal), and MT (Medium Thermal).

[0102] Specifically, examples of the above-mentioned SAF include Seto 9 (manufactured by Tokai Kodo Co., Ltd.), Seto Tokai N220 (manufactured by Showa Kodo Co., Ltd.) as ISAF, and HAF's Seto 3 (manufactured by Tokai Kono Co., Ltd.), Nitrono No. 200 (manufactured by Shinichi Chemical Co., Ltd.), and FEF's HTC #100 (manufactured by Chubu Kono Co., Ltd.), etc. Examples of other examples include Asahi #55 (manufactured by Asahi Carbon) and Seast 5 (manufactured by Tokai Carbon) as GPFs, Asahi #50 (manufactured by Asahi Carbon) and Mitsubishi #5 (manufactured by Mitsubishi Chemical) as SRFs, Asahi Surmar (manufactured by Asahi Carbon) as FTs, HTC #20 (manufactured by Chubu Carbon) and Asahi #15 (manufactured by Asahi Carbon) as MTs.

[0103] <Content>

[0104] In the composition of the present invention, the content of carbon black is not particularly limited, but for reasons of superior effect of the present invention, the content of the urethane prepolymer (A) described above is preferably 30 to 70% by mass, more preferably 40 to 60% by mass.

[0105] Calcium carbonate

[0106] For reasons of superior effects, the composition of the present invention preferably contains calcium carbonate.

[0107] There are no particular limitations on calcium carbonate. Examples include heavy calcium carbonate, precipitated calcium carbonate (light calcium carbonate), and colloidal calcium carbonate.

[0108] <Content>

[0109] In the composition of the present invention, the content of calcium carbonate is not particularly limited. However, for reasons of superior effect of the present invention, the content of the above-mentioned urethane prepolymer (A) is preferably 20 to 150% by mass, more preferably 20 to 120% by mass, and even more preferably 30 to 70% by mass.

[0110] [Plasticizer]

[0111] For reasons of superior effects, the composition of the present invention preferably contains a plasticizer.

[0112] Specific examples of plasticizers include diisononyl phthalate (DINP); dioctyl adipate and isodecanyl succinate; diethylene glycol dibenzoate and pentaerythritol ester; butyl oleate and methyl acetylacetonate; tricresyl phosphate and trioctyl phosphate; propylene glycol adipate and butylene glycol adipate, etc. One of them can be used alone or in combination with two or more.

[0113] <Content>

[0114] In the composition of the present invention, the content of plasticizer is not particularly limited, but for reasons of superior effect of the present invention, the content of the above-mentioned urethane prepolymer (A) is preferably 1 to 50% by mass, more preferably 5 to 40% by mass.

[0115] [Catalyst (Civilized Catalyst)]

[0116] For reasons of superior effects, the composition of the present invention preferably contains a curing catalyst.

[0117] There are no particular limitations on the solidification catalyst. Specific examples include carboxylic acids such as 2-ethylhexanoic acid and oleic acid; phosphoric acids such as polyphosphoric acid, ethyl phosphate, and butyl phosphate; bismuth catalysts such as bismuth octanoate; tin catalysts such as dibutyltin dilaurate and dioctyltin dilaurate; tertiary amine catalysts such as 1,4-diazabicyclo[2.2.2]octane, 2,4,6-tris(dimethylaminomethyl)phenol (e.g., DMP-30), and compounds containing the dimorpholinodiethyl ether structure.

[0118] Considering the superior adhesion, the curing catalyst preferably contains a dimorpholine diethyl ether structure.

[0119] The dimorpholine diethyl ether structure is a structure with dimorpholine diethyl ether as the basic framework.

[0120] In the dimorpholine diethyl ether structure, the hydrogen atoms of the morpholine ring can be replaced by substituents. There are no particular limitations on the substituents. Examples include alkyl groups. Examples of alkyl groups include methyl and ethyl groups.

[0121] The curing catalyst can be used individually or in combination of two or more types.

[0122] <Content>

[0123] In the composition of the present invention, the content of the curing catalyst is not particularly limited, but for reasons of superior effect of the present invention, the content of the urethane prepolymer (A) described above is preferably 0.05 to 2.0% by mass, more preferably 0.1 to 0.5% by mass.

[0124] [Manufacturing Method]

[0125] When the composition of the present invention is a liquid, its manufacturing method is not particularly limited. For example, it can be manufactured by mixing urethane prepolymer (A), compound (B), and other components as needed.

[0126] When the composition of the present invention is a two-liquid form, its manufacturing method is not particularly limited. For example, it can be manufactured by loading the above-mentioned main agent and the above-mentioned curing agent into different containers and mixing them in each container under a nitrogen atmosphere.

[0127] Alternatively, as a two-component application method, simply mix the above-mentioned main agent with the above-mentioned curing agent before use.

[0128] [Substrate]

[0129] Examples of substrates for which the compositions of the present invention can be applied include plastics, glass, rubber, and metals.

[0130] Suitable examples of substrates include substrates containing olefin resins.

[0131] The substrate containing olefin resin can also be composed of olefin resin and...

[0132] For example, a substrate is obtained by mixing a mixture of glass such as carbon fiber and glass filler, or fillers such as talc, calcium carbonate, or alumina.

[0133] Plastics can be, for example, homopolymers, copolymers, and hydrides. The same applies to rubber.

[0134] Specific examples of plastics include olefin resins such as polypropylene, polyethylene, ethylene-propylene copolymer, COP (cyclic olefin polymer), and COC (cyclic olefin copolymer);

[0135] Polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT);

[0136] Polymethyl methacrylate resin (PMMA resin); polycarbonate resin; polystyrene resin; acrylonitrile-styrene copolymer resin; polyvinyl chloride resin; acetate resin; ABS resin (acrylonitrile butadiene styrene resin); polyamide resin.

[0137] The COC mentioned above refers to a cyclic olefin copolymer, such as a copolymer of tetracyclic dodecene with olefins such as ethylene.

[0138] In addition, the aforementioned COP refers to, for example, a cyclic olefin polymer obtained by ring-opening polymerization and hydrogenation of norbornene.

[0139] Plastics can also be made from resins that are difficult to bond.

[0140] The substrate can also undergo surface treatment. Examples of surface treatments include flame treatment, corona treatment, and ITRO treatment. There are no particular limitations on the methods for each of the above surface treatments. Examples of methods known in the past can be cited.

[0141] There are no particular limitations on the method of applying the composition of the present invention to the substrate. Examples of methods known in the past can be cited.

[0142] When using the composition of the present invention, the effects of the present invention can be presented at an excellent level even without applying a primer to the substrate.

[0143] The compositions of the present invention can be cured using moisture or the like. For example, the compositions of the present invention can be cured at 5–90°C and relative humidity (RH) of 5–95%.

[0144] [use]

[0145] The compositions of the present invention are useful as sealants and adhesives, for example, for automotive, construction, and structural applications.

[0146] Example

[0147] The present invention will be described in more detail below through embodiments, but the present invention is not limited thereto.

[0148] [Preparation of Carbamate Adhesive Compositions]

[0149] Mix the components shown in Table 1 below in the proportions (parts by mass) shown in the table to prepare two-component urethane adhesive compositions (main agent and curing agent).

[0150] [evaluate]

[0151] The obtained urethane adhesive composition (main agent and curing agent) was mixed in the proportions listed in the mixing ratio column of Table 1 and allowed to cure for 3 days at 23°C and 50% RH. The strength, elongation, and hardness (initial) of the cured product were then measured as described below. Additionally, the strength, elongation, and hardness (after heat resistance) of the cured product were similarly measured after being allowed to stand at 90°C for 2 weeks. The results are shown in Table 1 below.

[0152] In practical applications, the initial strength is preferably 6.0 MPa or higher, the initial elongation is preferably 300% or higher, the strength after standing at 90°C for 2 weeks is preferably 5.5 MPa or higher, and the elongation after standing at 90°C for 2 weeks is preferably 200% or higher.

[0153] [Strength, elongation]

[0154] Tensile tests were conducted according to JIS K6850:1999 (tensile speed 50 mm / min, 20℃, 50% RH environment), and the strength (breaking strength) [MPa] and elongation (elongation at break) (%) were determined.

[0155] 〔hardness〕

[0156] The hardness was determined using a type A durometer in accordance with the durometer hardness test specified in JIS K6253 at an environment of 20°C and 55% RH.

[0157]

[0158] The details of each component in Table 1 above are as follows.

[0159] <Main Agent>

[0160] • Carbamate prepolymer: A carbamate prepolymer with isocyanate groups at the ends, obtained by means of the following method: 70 parts by weight of polyoxypropylene glycol (trade name Sannyx PP2000, manufactured by Sanyo Chemical Industry Co., Ltd., hydroxyl value 56, number average molecular weight 2,000), polyoxypropylene triol (trade name Sannyx GP3000, manufactured by Sanyo Chemical Industry Co., Ltd., hydroxyl value 56, number average molecular weight 3,000), and MDI (trade name Sumiju 44S, manufactured by Sumikawa Bioelur Uretan Co., Ltd.) are mixed such that the NCO / OH ratio is 2.0, and the mixture is reacted at 80°C for 5 hours.

[0161] ·GX-5170: The compound represented by formula (1) above (in formula (1), R is a hydrogen atom and n is 11) (belongs to the above compound (B)) (Cardolite Co., Ltd.)

[0162] ·GX-5167: The compound represented by formula (1) above (in formula (1), R is a hydrogen atom and n is 8) (belongs to the above compound (B)) (manufactured by Cardolite)

[0163] ·GX-5166: The compound represented by formula (1) above (in formula (1), R is a hydrogen atom and n is 6) (belongs to the above compound (B)) (manufactured by Cardolite)

[0164] • Isocyanurate: D-170N (HDI ureate, manufactured by Mitsui Chemicals)

[0165] ·LITE 2020: The compound represented by the above formula (1) (where R is a hydrogen atom and n is 0 in formula (1)) (Since n is 0 in formula (1), it does not belong to the above compound (B)) (Cardolite Co., Ltd.)

[0166] • Carbon black: #200MP (HAF grade carbon black) manufactured by Oshinka Carbon Co., Ltd.

[0167] ·Calcium carbonate: Maruo Calcium S (Heavy Calcium Carbonate)

[0168] Plasticizer: DINP (diisononyl phthalate), manufactured by Jeplastic Co., Ltd.

[0169] Catalyst: Sanya Pro UCAT-660M (DMDEE (dimorpholino diethyl ether))

[0170] <Curing agent>

[0171] • Polyol 1: EXCENOL 450ED (polyoxypropylene tetraol (EO (ethylene oxide) terminal), manufactured by Asahi Glass Co., Ltd., hydroxyl value 450 mg KOH / g, number average molecular weight 500)

[0172] • Polyol 2: PREMINOL 7001K (manufactured by Asahi Glass Co., Ltd., polyoxypropylene triol (EO (ethylene oxide) terminal), hydroxyl value 28 mg KOH / g, number average molecular weight 6,500)

[0173] • Calcium carbonate: Maruo Calsimu Co., Ltd. Calfin 200 (calcium carbonate obtained by surface treatment with fatty acids).

[0174] Catalyst: Nitto Kasei Corporation U-810 (Dioctyltin Dilaurate)

[0175] As shown in Table 1, the urethane adhesive compositions of Examples 1-7 containing compound (B) exhibited excellent rubber properties (strength, elongation) both initially and after heat resistance.

[0176] Based on the comparison of Examples 2 to 4 (comparison between examples where only the types of compound (B) differ), the heat-resistant rubber properties (strength, elongation, and hardness) of Examples 2 to 3, where n in Formula (1) is 8 or more, are superior. Among them, the heat-resistant rubber properties (strength, elongation, and hardness) of Example 2, where n in Formula (1) is 10 or more, are even more superior.

[0177] Furthermore, based on the comparison between Examples 2 and Examples 5-7 (comparison between examples where only the content of compound (B) differs), Examples 2 and Examples 5-6, with a compound (B) content of 0.01-20% by mass relative to the content of urethane prepolymer (A), exhibited superior rubber properties (strength, hardness) both initially and after heat resistance. Specifically, Examples 2 and Examples 5, with a compound (B) content of 0.1-2.0% by mass relative to the content of urethane prepolymer (A), showed further superior rubber properties (strength, hardness) both initially and after heat resistance. Specifically, Example 2, with a compound (B) content of 0.5-1.0% by mass relative to the content of urethane prepolymer (A), showed further superior rubber properties (strength, hardness) both initially and after heat resistance.

[0178] On the other hand, the carbamate adhesive compositions of Comparative Examples 1 to 3, which do not contain compound (B), are deficient in any of the rubber properties (strength, elongation) both initially and after heat resistance.

Claims

1. A two-component carbamate adhesive composition comprising: The main agent comprises a urethane prepolymer (A) having isocyanate groups at the ends, and a compound (B) represented by formula (1); and hardener, In formula (1), R represents a hydrogen atom or an alkyl group, and n represents an integer from 6 to 20. The content of compound (B) is 0.1 to 1% by mass relative to the total mass of the urethane adhesive composition.

2. The urethane adhesive composition according to claim 1, wherein the urethane prepolymer (A) is obtained by mixing and reacting a polyether polyol with a number average molecular weight of 500 to 20,000 with an aromatic polyisocyanate in a ratio of 1.5 to 2.5 moles of isocyanate groups in the aromatic polyisocyanate to 1 mole of hydroxyl groups in the polyether polyol.

3. The urethane adhesive composition according to claim 1 or 2, further comprising carbon black or calcium carbonate.

4. The urethane adhesive composition according to claim 1, further comprising an isocyanurate body of isocyanate, a ureocarbamate body of isocyanate, or a biuret body of isocyanate.

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