JP7529622B2 - Urethane adhesive composition - Google Patents

Description

The present invention relates to a urethane adhesive composition.

Conventionally, adhesive compositions containing urethane prepolymers, carbon black, etc. have been known as adhesives that can be used for automobiles (e.g., Patent Documents 1 and 2).

International Publication No. 2016/159237 JP 2012-111898 A

Adhesive compositions for automobiles are usually required to have excellent thermal stability during production, workability and stability during use, and physical properties of the resulting cured product (initial and post-aging physical properties), and in recent years, these required levels have been increasing.
Under these circumstances, the present inventors referred to Patent Document 1 and prepared and evaluated a urethane-based adhesive composition containing a urethane prepolymer, carbon black, etc., and found that there was room for improvement in order for the urethane-based adhesive composition to satisfy all of the above-mentioned required levels.
Furthermore, when a crystallization agent is added to a one-component moisture-curing type urethane adhesive composition as disclosed in Patent Document 2, there is a risk that the crystallization agent will impair the above-mentioned properties of the urethane adhesive composition (Comparative Example 3 of Patent Document 2).

The present invention aims to provide a urethane adhesive composition that has excellent thermal stability during production, workability and stability during use, physical properties of the resulting cured product (initial and post-aging physical properties; the same applies below), and adhesive properties.

As a result of intensive research into solving the above-mentioned problems, the present inventors have found that the desired effects can be obtained by containing a urethane prepolymer, carbon blacks A and B each having a dibutyl phthalate oil absorption within a specific range, a white filler C, a plasticizer D, a modified aliphatic diisocyanate E, a thermoplastic polyester F having a plurality of aliphatic hydrocarbon groups to which isocyanate groups are bonded, and a catalyst, whereby each of the above A to E is in a specific content, and the contents of A and B satisfy a specific relationship, thereby arriving at the present invention.
The present invention is based on the above findings and has the following specific configuration to solve the above problems.

[1]
A urethane prepolymer;
Carbon black A having a dibutyl phthalate oil absorption of 30 to 40 ml/100 g;
Carbon black B having a dibutyl phthalate oil absorption of 98 to 108 ml/100 g;
White filler C;
A plasticizer D; and
A modified aliphatic diisocyanate E;
a thermoplastic polyester F having a plurality of aliphatic hydrocarbon groups to which isocyanate groups are bonded;
A catalyst;
A one-component moisture-curing urethane adhesive composition that satisfies all of the following (1) to (6), with the proviso that the modified product E does not have an ester bond.
[2]
The urethane adhesive composition according to [1], wherein the melting point of the thermoplastic polyester polyol constituting the thermoplastic polyester F is 55 to 65°C.
[3]
The urethane adhesive composition according to [1] or [2], wherein in the thermoplastic polyester F, the aliphatic hydrocarbon group to which the isocyanate group is bonded is derived from an aliphatic diisocyanate.
[4]
The urethane adhesive composition according to any one of [1] to [3], wherein the content f of the thermoplastic polyester F is 3 to 8 parts by mass per 100 parts by mass of the urethane prepolymer.
[5]
The urethane adhesive composition according to any one of [1] to [4], wherein the modified product E contains a vuret product of hexamethylene diisocyanate and/or an isocyanurate product of hexamethylene diisocyanate.
[6]
The urethane adhesive composition according to any one of [1] to [5], wherein the white filler C contains calcium carbonate.
[7]
The urethane adhesive composition according to any one of [1] to [6], wherein the plasticizer D comprises a phthalate ester and/or an adipic acid ester.

The urethane adhesive composition of the present invention has excellent thermal stability during production, workability and stability during use, and the physical properties and adhesiveness of the resulting cured product.

The present invention will be described in detail below.
In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In this specification, unless otherwise specified, each component may be used alone or in combination of two or more of the substances corresponding to that component. When a component contains two or more substances, the content of the component means the total content of the two or more substances, unless otherwise specified.
In this specification, the effect of the present invention may be said to be superior when it means that at least one of thermal stability during production, workability during use, stability during use, physical properties of the obtained cured product, and adhesiveness is superior.

[Urethane-based adhesive composition]
The urethane-based adhesive composition of the present invention (adhesive composition of the present invention) contains a urethane prepolymer, carbon black A having a dibutyl phthalate oil absorption of 30 to 40 ml/100 g, carbon black B having a dibutyl phthalate oil absorption of 98 to 108 ml/100 g, a white filler C, a plasticizer D, a modified aliphatic diisocyanate E, a thermoplastic polyester F having a plurality of aliphatic hydrocarbon groups to which isocyanate groups are bonded, and a catalyst;
A urethane-based adhesive composition that satisfies all of the following (1) to (6), with the exception that the modified product E does not have an ester bond.
(1) 25≦a≦35
(2) 55≦b≦75
(3) 197≦a+3b≦251
(4) 30≦c≦35
(5) 35≦d≦45
(6) 2.5≦e≦3.7
In the above (1) to (6), a represents the content of carbon black A, b represents the content of carbon black B, c represents the content of white filler C, d represents the content of plasticizer D, and e represents the content of modified substance E. Note that the above a is the amount (unit: parts by mass) relative to 100 parts by mass of the urethane prepolymer. The same applies to b, c, d, and e.
Each component contained in the adhesive composition of the present invention will be described in detail below.

[Urethane prepolymer]
The urethane prepolymer contained in the adhesive composition of the present invention is a urethane prepolymer having an isocyanate group.
However, in the present invention, the urethane prepolymer does not include the thermoplastic polyester F described below. Also, in the present invention, the urethane prepolymer does not include the modified product E described below.
In one preferred embodiment, the urethane prepolymer has an isocyanate group at its terminal.

An example of a urethane prepolymer is one obtained by reacting a polyisocyanate with a compound having two or more active hydrogen-containing groups in one molecule (active hydrogen compound) such that the isocyanate groups of the polyisocyanate are in excess relative to the active hydrogen-containing groups of the active hydrogen compound.
Isocyanate Group Content The isocyanate group content of the urethane prepolymer is preferably 0.5 to 5 mass % of the total amount of the urethane prepolymer.

Polyisocyanate The polyisocyanate used in producing the urethane prepolymer is not particularly limited as long as it has two or more isocyanate groups in the molecule.
Examples of polyisocyanates that can be used in producing the urethane prepolymer include aromatic polyisocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI; e.g., 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), and triphenylmethane triisocyanate;
Aliphatic polyisocyanates (including alicyclic polyisocyanates) such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornane diisocyanate (NBDI), transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis(isocyanatomethyl)cyclohexane (H ₆ XDI), and dicyclohexylmethane diisocyanate (H ₁₂ MDI) are included.

Of these, the polyisocyanate preferably contains an aromatic polyisocyanate, and more preferably contains MDI, because of its excellent curing properties.

Active hydrogen compound The compound having two or more active hydrogen-containing groups in one molecule (active hydrogen compound) that can be used in producing the urethane prepolymer is not particularly limited. Examples of the active hydrogen-containing group include a hydroxyl (OH) group, an amino group, and an imino group.
Suitable examples of active hydrogen compounds include polyol compounds having two or more hydroxyl (OH) groups in one molecule, and among these, polyol compounds are preferred.

The polyol compound that can be used in producing the urethane prepolymer is not particularly limited as long as it is a compound having two or more hydroxyl groups. Examples include polyether polyols; polymer polyols having carbon-carbon bonds in the main chain such as acrylic polyols, polybutadiene diols, and hydrogenated polybutadiene polyols; low molecular weight polyhydric alcohols; and mixed polyols of these. Among these, polyether polyols are one of the preferred embodiments.

Examples of polyether polyols include polyoxyethylene diol (polyethylene glycol), polyoxypropylene diol (polypropylene glycol: PPG), polyoxypropylene triol, ethylene oxide/propylene oxide copolymer, polytetramethylene ether glycol (PTMEG), polytetraethylene glycol, and sorbitol-based polyols.

The polyether polyol is preferably polypropylene glycol or polyoxypropylene triol from the viewpoint of excellent compatibility with the polyisocyanate.
The weight average molecular weight of the polyether polyol is preferably 500 to 20,000 from the viewpoint that the viscosity of the urethane prepolymer obtained by the reaction with the isocyanate can have an appropriate fluidity at room temperature (23° C.) In the present invention, the weight average molecular weight is a polystyrene-equivalent value obtained by the GPC method (solvent: tetrahydrofuran (THF)).

From the viewpoint of excellent adhesiveness and curing properties, the urethane prepolymer preferably contains a urethane prepolymer obtained by reacting a polyether polyol with an aromatic polyisocyanate, and more preferably contains a urethane prepolymer obtained by reacting at least one selected from the group consisting of polyoxypropylene diol and polyoxypropylene triol with diphenylmethane diisocyanate.

The method for producing the urethane prepolymer is not particularly limited. For example, a polyisocyanate is used so that 1.5 to 2.5 moles of isocyanate groups react with 1 mole of active hydrogen-containing groups (e.g., hydroxyl groups) of the active hydrogen compound, and the urethane prepolymer can be produced by mixing and reacting them.
In producing the urethane prepolymer, a plasticizer D described below may be used.

[Carbon Black A]
In the present invention, carbon black A is carbon black having a dibutyl phthalate oil absorption (DBP oil absorption) of 30 to 40 ml/100 g.
By containing carbon black A, the adhesive composition of the present invention has excellent thermal stability during production, and the physical properties (for example, shear strength retention) and adhesiveness of the resulting cured product are excellent.

-Method for measuring dibutyl phthalate oil absorption of carbon black In the present invention, the dibutyl phthalate oil absorption of carbon black was measured in accordance with JIS K 6217-4:2008 "Carbon black for rubber-Fundamental properties-Part 4: Determination of oil absorption."

Suitable Examples of Carbon Black A Examples of carbon black A include FT and MT grade carbon blacks, which have a DBP oil absorption of 30 to 40 ml/100 g.

[Carbon Black B]
In the present invention, carbon black B is carbon black having a dibutyl phthalate oil absorption (DBP oil absorption) of 98 to 108 ml/100 g.
By containing carbon black B, the adhesive composition of the present invention has excellent stability during use (e.g., viscosity, triangular bead retention), excellent stability during use (e.g., low heat generation in a constant flow pump), and excellent physical properties of the obtained cured product (e.g., tensile modulus, elongation at break, shear strength retention).

The method for measuring the dibutyl phthalate oil absorption of carbon black B is the same as above.

Suitable Examples of Carbon Black B Examples of carbon black B include ISAF, HAF, and HAF-LS grade carbon blacks, which have a DBP oil absorption of 98 to 108 ml/100 g.

[White filler C]
The adhesive composition of the present invention contains a white filler C.
By containing the white filler C, the adhesive composition of the present invention has excellent workability during use (eg, deep curing ability) and excellent physical properties of the resulting cured product (eg, elongation at break).

Suitable examples of white filler C In the present invention, there are no particular limitations on the white filler C. Examples include calcium carbonate, talc, clay, and silica.
From the viewpoint of obtaining superior effects of the present invention, the white filler C preferably contains calcium carbonate, and more preferably contains ground calcium carbonate.

Heavy Calcium Carbonate Here, heavy calcium carbonate is obtained by mechanically crushing or processing natural chalk, limestone, marble, etc.

Surface Treatment The white filler C may be one that has been surface-treated using a surface treatment agent such as a fatty acid ester. The white filler C may also be an untreated one that has not been surface-treated.
From the viewpoint of obtaining a superior effect of the present invention, it is preferable that the white filler C contains calcium carbonate that has not been surface-treated.

From the viewpoint of obtaining a superior effect of the present invention, the 50% cumulative particle diameter of the white filler C is preferably 1 to 10 μm. In the present invention, the 50% cumulative particle diameter of the white filler C was measured in accordance with JIS M 8511.

[Plasticizer D]
The plasticizer D contained in the adhesive composition of the present invention is not particularly limited as long as it is a compound that can plasticize or soften the urethane prepolymer and is compatible with and unreactive with the urethane prepolymer.
By including plasticizer D, the adhesive composition of the present invention has excellent thermal stability during production, workability and stability during use, and physical properties of the resulting cured product.

Examples of plasticizers D include phthalate esters, adipic acid esters, diethylene glycol dibenzoate, pentaerythritol esters, and butyl oleate.

Suitable Examples of Plasticizer D From the viewpoint of achieving superior effects of the present invention, plasticizer D preferably contains a phthalate ester and/or an adipic acid ester, more preferably contains a phthalate diester and/or an adipic acid diester, and even more preferably contains a phthalate diester and an adipic acid diester.

Phthalic acid diesters include, for example, phthalic acid dialkyl esters such as diisononyl phthalate (DINP).
Examples of the adipic acid diester include dialkyl adipic acid esters such as dioctyl adipate and diisononyl adipate (DINA).

When plasticizer D contains a phthalate ester and/or an adipic acid ester, the content of the phthalate ester and/or the adipic acid ester (the total content of the phthalate ester and the adipic acid ester when the phthalate ester and the adipic acid ester are used in combination) is preferably 80 to 100% by mass, and more preferably 90 to 100% by mass, of the total amount of plasticizer D, from the viewpoint of achieving a better effect of the present invention.

Plasticizer D may be used in producing the above-mentioned urethane prepolymer, in which case the urethane prepolymer may be in a mixture with plasticizer D.
Furthermore, plasticizer D may be used by adding it later to the urethane prepolymer produced as described above (the urethane prepolymer may be a mixture with a part of plasticizer D).
A portion of the plasticizer D may be added to the catalyst described below, and the catalyst may be used as a mixture of the catalyst and the plasticizer.

[Modified product E]
The modified product E contained in the adhesive composition of the present invention is a modified product constituted by an aliphatic diisocyanate.
However, in the present invention, modified product E does not have an ester bond (-C-COO-C-). Further, the above-mentioned urethane prepolymer does not include modified product E.
By containing Modified Product E, the adhesive composition of the present invention has excellent thermal stability during production, workability and stability during use, and the physical properties and adhesiveness of the resulting cured product.

Isocyanate Group From the viewpoint of achieving superior effects of the present invention, Modified Product E preferably has an isocyanate group derived from an aliphatic diisocyanate, more preferably has a plurality of the isocyanate groups per molecule, and further preferably has 3 to 6 isocyanate groups per molecule.

When two or more molecules of aliphatic diisocyanate constitute one molecule of the modified substance E, the aliphatic diisocyanates may be the same or different compounds. In one preferred embodiment, the three aliphatic diisocyanates are the same.
From the viewpoint of achieving superior effects of the present invention, it is preferable that the modified product E contains a trimer of an aliphatic diisocyanate.

Specific examples of modified substance E include a reaction product of a tri- or higher functional polyol with an aliphatic diisocyanate, an allophanate of an aliphatic diisocyanate, a trimer of an aliphatic diisocyanate derived from an allophanate of an aliphatic diisocyanate, an isocyanurate of an aliphatic diisocyanate (a trimer of an aliphatic diisocyanate), and a vuret of an aliphatic diisocyanate (a trimer of an aliphatic diisocyanate).
From the viewpoint of achieving better effects of the present invention, the modified product E preferably contains at least one selected from the group consisting of a reaction product of a tri- or higher functional polyol with an aliphatic diisocyanate, a trimer of an aliphatic diisocyanate derived from an allophanate of an aliphatic diisocyanate, an isocyanurate (nurate) of an aliphatic diisocyanate, and a vuret of an aliphatic diisocyanate,
It is more preferable that the isocyanurate (nurate) of an aliphatic diisocyanate and/or a vuret of an aliphatic diisocyanate is contained.
It is further preferable that the isocyanurate of HDI and/or the vuret of HDI are contained,
It is particularly preferred to include a vulcanized form of HDI.

The aliphatic diisocyanate that can constitute the modified product E is not particularly limited as long as it is an aliphatic hydrocarbon compound having two isocyanate groups in one molecule.
Examples of the aliphatic diisocyanate include aliphatic diisocyanates (including alicyclic diisocyanates) such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornane diisocyanate (NBDI), transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis(isocyanatomethyl)cyclohexane (H ₆ XDI), and dicyclohexylmethane diisocyanate (H ₁₂ MDI).
Among these, the aliphatic diisocyanate capable of constituting the modified product E is preferably a linear aliphatic diisocyanate, more preferably HDI, from the viewpoint of obtaining superior effects of the present invention.

From the viewpoint of achieving a more excellent effect of the present invention, it is preferable that the modified substance E contains a trifunctional compound (EE) (having three isocyanate groups) modified from hexamethylene diisocyanate (HDI).

Examples of the trifunctional compound (EE) modified with hexamethylene diisocyanate include reaction products of trifunctional polyols such as trimethylolpropane (TMP) and glycerin with hexamethylene diisocyanate;
Isocyanurate form (nurate form) of hexamethylene diisocyanate;
An example is the Vurette form of hexamethylene diisocyanate.

...Reaction Product of Trifunctional Polyol and Hexamethylene Diisocyanate Examples of the reaction product of a trifunctional polyol and hexamethylene diisocyanate include a reaction product of TMP and HDI (e.g., a compound represented by the following formula (5)) and a reaction product of glycerin and HDI (e.g., a compound represented by the following formula (6)).

--Trimers of HDI derived from allophanate of hexamethylene diisocyanate The trimers of HDI derived from allophanate of hexamethylene diisocyanate are not particularly limited.

...Vuillet Derivative of Hexamethylene Diisocyanate An example of the Vuillet derivative of hexamethylene diisocyanate is a compound represented by the following formula (7).

...Isocyanurate of Hexamethylene Diisocyanate Examples of the isocyanurate of hexamethylene diisocyanate (nurate) include a compound represented by the following formula (8).

[Thermoplastic polyester F]
The thermoplastic polyester F contained in the adhesive composition of the present invention is a thermoplastic polymer having a plurality of aliphatic hydrocarbon groups to which isocyanate groups are bonded, and whose main chain skeleton is a thermoplastic polyester.
In the present invention, the thermoplastic polyester F is not included in the above-mentioned urethane prepolymer and the above-mentioned modified product E.
The adhesive composition of the present invention contains thermoplastic polyester F. After the adhesive composition of the present invention is applied to an adherend, the thermoplastic polyester F solidifies, thereby increasing the cohesive strength of the adhesive composition of the present invention, so that the initial strength of the adhesive layer is quickly developed and the adherend can be temporarily attached.
Furthermore, even if the adhesive composition of the present invention contains thermoplastic polyester F, the effects of the present invention are not impaired by the thermoplastic polyester F.

Aliphatic Hydrocarbon Group to Which Isocyanate Groups Are Bonded In the present invention, the thermoplastic polyester F has a plurality of aliphatic hydrocarbon groups to which isocyanate groups are bonded.
The aliphatic hydrocarbon group to which the isocyanate group is bonded can be represented as (NCO)n-R-, where R represents an (n+1) valent aliphatic hydrocarbon group, and n is 1 or more.
The (n+1)-valent aliphatic hydrocarbon group may be linear, branched, cyclic, or a combination thereof. From the viewpoint of achieving a superior effect of the present invention and of quickly developing the initial strength of the adhesive layer, the (n+1)-valent aliphatic hydrocarbon group is preferably linear, and more preferably a linear aliphatic hydrocarbon group having 4 to 8 carbon atoms.
In (NCO)n-R-, n is preferably 1 from the same viewpoint as described above for the (n+1) valent aliphatic hydrocarbon group.
From the same viewpoint as described above for the (n+1)-valent aliphatic hydrocarbon group, the thermoplastic polyester F preferably has two aliphatic hydrocarbon groups to which isocyanate groups are bonded per molecule.

In the thermoplastic polyester F, the aliphatic hydrocarbon group to which the isocyanate group is bonded is preferably derived from an aliphatic diisocyanate, from the viewpoints of achieving a better effect of the present invention and of quickly developing the initial strength of the adhesive layer.
The aliphatic diisocyanate that can be used to form the thermoplastic polyester F is not particularly limited as long as it is a compound in which two isocyanate groups are bonded to an aliphatic hydrocarbon group. For example, the aliphatic polyisocyanate that can be used in producing the above-mentioned urethane prepolymer can be used. Among them, it is preferable to include hexamethylene diisocyanate from the viewpoint of more excellent effects of the present invention and early development of strength of the adhesive layer.

Thermoplastic Polyester as Main Chain Skeleton Thermoplastic polyester F has a thermoplastic polyester as the main chain skeleton.
Examples of the main chain skeleton include condensation polymers of low molecular weight polyols such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerin, and 1,1,1-trimethylolpropane, and low molecular weight polycarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, terephthalic acid, isophthalic acid, and dimer acid.
From the viewpoint of achieving a superior effect of the present invention and rapid development of the initial strength of the adhesive layer, the above-mentioned main chain skeleton preferably has a polyester formed from hexanediol and sebacic acid.

In the thermoplastic polyester F, the main chain skeleton is preferably derived from a thermoplastic polyester polyol, and more preferably from a thermoplastic polyester diol, from the viewpoints of achieving a better effect of the present invention and of quickly developing the initial strength of the adhesive layer.

Melting Point of Thermoplastic Polyester Polyol From the viewpoint of achieving a better effect of the present invention and quickly developing the initial strength of the adhesive layer, the melting point of the thermoplastic polyester polyol that can constitute the thermoplastic polyester F is preferably 55 to 65° C., more preferably 56 to 60° C. The melting point can be measured by DSC at a temperature rise rate of 10° C./min.
In the present invention, the melting point of the above thermoplastic polyester polyol can be treated as the melting point of the thermoplastic polyester F.

Weight-average molecular weight of thermoplastic polyester polyol From the viewpoints of obtaining a better effect of the present invention and quickly developing initial strength without being too high in melting temperature, the weight-average molecular weight (Mw) of the thermoplastic polyester polyol that can constitute thermoplastic polyester F is preferably 1700 to 2300. The Mw of the thermoplastic polyester polyol that can constitute thermoplastic polyester F can be expressed as a polystyrene equivalent value by gel permeation chromatography using tetrahydrofuran as a solvent.

Bonds In the thermoplastic polyester F, there are no particular limitations as to whether the aliphatic hydrocarbon group to which the isocyanate group is bonded is bonded to the terminal of the main chain or to a side chain.
The aliphatic hydrocarbon group to which the isocyanate group is bonded can be bonded to the end of the main chain skeleton directly or via a linking group, and is preferably bonded to the end. The linking group is not particularly limited. For example, a urethane bond or a urea bond can be mentioned.

- Preferred Example From the viewpoint of achieving a better effect of the present invention and quickly developing the initial strength of the adhesive layer, it is preferred that the thermoplastic polyester F contains a polymer in which an aliphatic hydrocarbon group having one isocyanate group is bonded to each of both ends of a linear thermoplastic polyester.

Preparation Method There is no particular limitation on the preparation method of the thermoplastic polyester F. For example, the thermoplastic polyester F can be obtained by reacting a thermoplastic polyester polyol with an aliphatic diisocyanate at 75 to 85° C. in an amount such that the molar ratio of the isocyanate groups of the aliphatic diisocyanate to the hydroxyl groups of the thermoplastic polyester polyol is 1.9 to 2.1.

Content of thermoplastic polyester F f
The content f of thermoplastic polyester F is preferably 3 to 8 parts by mass (3≦f≦8) per 100 parts by mass of the urethane prepolymer, from the viewpoint of achieving better effects of the present invention and quickly developing the initial strength of the adhesive layer.

〔catalyst〕
The catalyst contained in the adhesive composition of the present invention is not particularly limited as long as it is a compound capable of promoting the reaction of an isocyanate group, and examples thereof include metal catalysts and amine catalysts.
The content of the catalyst (when two or more types of catalysts are used in combination, the total content of these) is preferably 0.01 to 5.0 parts by mass per 100 parts by mass of the urethane prepolymer, in terms of achieving better effects of the present invention and excellent moisture curing properties.

Metal Catalyst The metal catalyst that can be contained in the adhesive composition of the present invention is not particularly limited as long as it is a metal compound that can promote the reaction of an isocyanate group. For example, an organometallic catalyst can be mentioned.
Examples of the metal contained in the metal catalyst include tin, bismuth, and titanium.

The organic group of the organometallic catalyst is not particularly limited. Examples of the organometallic catalyst include metal carboxylates, alkoxides, and complexes. The organometallic catalyst may have at least one selected from the group consisting of, for example, a carboxylic acid, an alkoxy group, and a ligand. The carboxylic acid, alkoxy group, and ligand are not particularly limited.

--Organotin Catalyst The metal catalyst preferably comprises an organotin catalyst.

Examples of organic tin catalysts include tetravalent tin carboxylates such as dioctyltin dilaurate, dibutyltin dilaurate, dibutyltin maleate, stannous octoate, dibutyltin diacetylacetonate, and dioctyltin maleate; organic compounds of divalent tin; and the reaction product of 1,3-diacetoxy-1,1,3,3-tetrabutyl-distannoxane and ethyl silicate.

--Organotitanium Catalyst Examples of the organotitanium catalyst include tetrapropyl titanate, tetrabutyl titanate, tetraoctyl titanate, and titanium diisopropoxybis(ethylacetoacetate).

Metal Catalyst Content The content of the metal catalyst is preferably 0.0003 to 0.04 parts by mass, more preferably 0.0004 to 0.03 parts by mass, and even more preferably 0.005 to 0.02 parts by mass, per 100 parts by mass of the urethane prepolymer, in that the effects of the present invention are more excellent.

Amine Catalyst The amine catalyst that can be contained in the adhesive composition of the present invention is a compound that has a nitrogen atom and promotes the reaction of an isocyanate group.

--Amine Catalyst Having a Tertiary Amino Group The amine catalyst preferably has a tertiary amino group (one nitrogen atom is single-bonded to three carbon atoms, or one nitrogen atom is single-bonded to one carbon atom and double-bonded to another carbon atom).
Examples of the amine catalyst having a tertiary amino group (tertiary amine) include tertiary amines (excluding compounds having an ether bond) such as trimethylamine, triethylamine, tripropylamine, tributylamine, triamylamine, trihexylamine, trioctylamine, trilaurylamine, dimethylethylamine, dimethylpropylamine, dimethylbutylamine, dimethylamylamine, dimethylhexylamine, dimethylcyclohexylamine, dimethyloctylamine, dimethyllaurylamine, triallylamine, tetramethylethylenediamine, triethylenediamine, N,N-dimethylbenzylamine, pyridine, methylpyridine (picoline), dimethylaminomethylphenol, trisdimethylaminomethylphenol, 1,8-diazabicyclo[5.4.0]undecene, 1,1,4-diazabicyclo[2.2.2]octane, triethanolamine, N,N'-dimethylpiperazine, and tetramethylbutanediamine; and tertiary amines having an ether bond.

Examples of tertiary amines having an ether bond include tertiary amines having a chain ether structure such as bis(dimethylaminoethyl)ether (tertiary amines having a chain ether structure do not have a ring structure); monomorpholine compounds such as N-methylmorpholine and dimethylaminoethylmorpholine; and compounds in which a plurality of morpholine rings are bonded via ether bonds.
Examples of compounds in which a plurality of morpholine rings are bonded via ether bonds include bis(morpholinoalkyl)ethers. In the bis(morpholinoalkyl)ethers, the alkylene group between the nitrogen atom of each morpholine ring and the oxygen atom (excluding the oxygen atom of the morpholine ring) constituting the ether bond is not particularly limited. For example, an ethylene group can be mentioned.

Bis(morpholinoalkyl)ether structure The above bis(morpholinoalkyl)ethers preferably contain a bis(morpholinoalkyl)ether structure, in that the effects of the present invention are more excellent and the moisture curing properties are excellent.
In the bis(morpholinoalkyl)ether structure, the hydrogen atom of the morpholine ring may be substituted with a substituent. The substituent is not particularly limited. For example, an alkyl group may be used. For example, the alkyl group may be a methyl group or an ethyl group.

Examples of bis(morpholinoalkyl)ethers include compounds represented by the following formula (1).
In the above formula (1), R ¹ and R ² each independently represent an alkyl group; m and n each independently represent 0, 1 or 2.
Specific examples of bis(morpholinoalkyl)ethers include bis(2-morpholinoethyl)ether (structure shown below), bis(methylmorpholinoethyl)ether, and bis(dimethylmorpholinoethyl)ether.

From the viewpoint of achieving a more excellent effect of the present invention and excellent moisture curing property, the catalyst preferably contains a carboxylate of tetravalent tin, a tertiary amine having a chain ether structure (having no ring structure), a monomorpholine compound, and a compound in which a plurality of morpholine rings are bonded via ether bonds,
More preferably, the compound contains dioctyltin dilaurate, bis(dimethylaminoethyl)ether, dimethylaminoethylmorpholine, and bis(2-morpholinoethyl)ether.

Amine Catalyst Content The amine catalyst content (when there are two or more types of amine catalysts, the content of each amine catalyst) is preferably 0.01 to 1.0 part by mass, more preferably 0.02 to 0.4 part by mass, and even more preferably 0.08 to 0.2 part by mass, relative to 100 parts by mass of the urethane prepolymer, in that the effects of the present invention are more excellent and moisture curing property is excellent.
When two or more types of amine catalysts are used, the total content of the two or more amine catalysts is preferably 0.04 to 5.0 parts by mass per 100 parts by mass of the urethane prepolymer, in that the effects of the present invention are more excellent and moisture curing properties are excellent.

[(1)]
The adhesive composition of the present invention satisfies the following (1).
(1) 25≦a≦35
In the above (1), a represents the content of the carbon black A relative to 100 parts by mass of the urethane prepolymer.
In this specification, a may be expressed as the content a. The same applies to b to e. In the present invention, the units of a to e are parts by mass.
From the viewpoint of obtaining superior effects of the present invention, the content a is preferably 28 to 33 parts by mass per 100 parts by mass of the urethane prepolymer.

[(2)]
The adhesive composition of the present invention satisfies the following (2).
(2) 55≦b≦75
In the above (2), b represents the content of the carbon black B relative to 100 parts by mass of the urethane prepolymer.
From the viewpoint of obtaining superior effects of the present invention, the content b is preferably 59 to 70 parts by mass, and more preferably 60 to 65 parts by mass, per 100 parts by mass of the urethane prepolymer.

(3)
The adhesive composition of the present invention satisfies the following (3).
(3) 197≦a+3b≦251
In the above (3), a represents the content a, and b represents the content b.
From the viewpoint of obtaining superior effects of the present invention, a+3b is preferably from 205 to 240, and more preferably from 210 to 229.

(4)
The adhesive composition of the present invention satisfies the following (4).
(4) 30≦c≦35
In the above (4), c represents the content of the white filler C relative to 100 parts by mass of the urethane prepolymer.

(5)
The adhesive composition of the present invention satisfies the following (5).
(5) 35≦d≦45
In the above (5), d represents the content of the plasticizer D relative to 100 parts by mass of the urethane prepolymer.

(6)
The adhesive composition of the present invention satisfies the following (6).
(6) 2.5≦e≦3.7
In the above (6), e represents the content of the modified product E relative to 100 parts by mass of the urethane prepolymer.

(Additive)
The adhesive composition of the present invention may further contain additives as necessary within the scope of the present invention. Examples of additives include fillers other than carbon black A, B and white filler C, urethane prepolymers, isocyanate compounds other than modified product E and thermoplastic polyester F, antioxidants, antioxidants, thixotropy-imparting agents, ultraviolet absorbers, flame retardants, surfactants, dispersants, dehydrating agents, and heat stabilizers such as diethyl malonate.

(Production method)
The adhesive composition of the present invention is not particularly limited by its production method. For example, the adhesive composition of the present invention can be produced by stirring and mixing the urethane prepolymer, carbon black A, carbon black B, white filler C, plasticizer D, modified product E, thermoplastic polyester F, catalyst, and additives that can be used as needed at room temperature or under heated conditions (e.g., 40 to 60°C) using a roll, kneader, extruder, universal mixer, continuous mixer, or the like.

[First solution]
The adhesive composition of the present invention is a one-liquid (single-part type) composition.

・How to use (heating)
When applying the adhesive composition of the present invention to an adherend, it is preferable to heat the adhesive composition of the present invention. By heating the adhesive composition of the present invention, the viscosity of the adhesive composition of the present invention becomes within an appropriate range for work, making it easier to apply.
When applying the adhesive composition of the present invention to an adherend, it is preferable to heat the adhesive composition of the present invention, for example, at a temperature equal to or higher than the melting point of the thermoplastic polyester F (or the melting point of the thermoplastic polyester polyol constituting the thermoplastic polyester F). Moreover, from the viewpoint of obtaining superior effects of the present invention (particularly, stability of the adhesive composition during use), the heating temperature is preferably 70° C. or lower.

When applying the adhesive composition of the present invention to an adherend, the method for heating the adhesive composition of the present invention is not particularly limited. For example, a conventionally known method can be used.
In addition, when applying the adhesive composition of the present invention to an adherend, the pump used to deliver the adhesive composition of the present invention is not particularly limited. For example, an internal gear type pump in which an external gear and an internal gear rotate by meshing with each other (specifically, for example, a pump generally called a trochoid pump) can be mentioned. For example, a commercially available pump is the Trochoid (registered trademark) pump (manufactured by Nippon Oil Pump Co., Ltd.).

Adherend The adhesive composition of the present invention can be applied to any adherend without particular limitation, and examples thereof include metals (including painted plates), plastics, rubber, and glass.
The coated plate is not particularly limited. For example, a conventionally known coating may be used. The coating used for the coated plate is not particularly limited.
The method for applying the adhesive composition of the present invention to an adherend is not particularly limited, and may be, for example, a conventionally known method.
The adhesive composition of the present invention can be applied to an adherend without using a primer, for example, a painted plate.

When the adhesive composition of the present invention is used in a direct glazing method for bonding an automobile window glass to a body (painted plate), the adhesive composition of the present invention can be applied directly to the body without using a primer on the body. A primer may be used on the glass side. There are no particular restrictions on the primer used on the adherend.

Method of Use The adhesive composition of the present invention can be used, for example, by applying the heated adhesive composition of the present invention to an adherend under room temperature (23°C) conditions and laminating another adherend. After laminating another adherend, the heated adhesive composition of the present invention cools, solidifying the adhesive composition of the present invention and exerting the initial strength of the adhesive layer, allowing the adherend to be temporarily fixed. Thereafter, the adhesive composition of the present invention is further moisture-cured, thereby further improving the adhesive strength and allowing the adherends to be bonded with excellent adhesive strength.

[Moisture curing type]
The adhesive composition of the present invention is of the moisture curing type and can be cured by moisture (eg, atmospheric moisture).
The adhesive composition of the present invention can be cured, for example, under conditions of −20 to +50° C. In addition, since the adhesive composition of the present invention can be moisture cured, it is not necessary to heat the adhesive composition of the present invention after application to an adherend.

The present invention will be specifically explained below with reference to examples. However, the present invention is not limited to these examples.

(Preparation of Urethane Prepolymer 1 ^* )
500 g of polyoxypropylene diol (weight average molecular weight 2000, Exenol 2020, manufactured by AGC), 750 g of polyoxypropylene triol (weight average molecular weight 5000, Exenol 5030, manufactured by AGC), and 214 g of 4,4'-diphenylmethane diisocyanate (molecular weight 250) were mixed (NCO/OH (molar ratio) at this time = 1.8), and 160 g of diisononyl adipate (DINA) was further added, and the mixture was stirred at 80 ° C. for 24 hours in a nitrogen stream to react, synthesizing urethane prepolymer 1 containing 1.95 mass % isocyanate groups, and a mixture of the above urethane prepolymer 1 and diisononyl adipate as a plasticizer was obtained.
In the above mixture, the content of diisononyl adipate was 10.9 parts by mass per 100 parts by mass of the pure urethane prepolymer 1.

When urethane prepolymer 1 is used as the urethane prepolymer, the diisononyl adipate used in preparing urethane prepolymer 1 is included in the "Plasticizer D1" column in Table 1, and 10.9 parts by mass of the "Total amount of plasticizer (D)" is diisononyl adipate associated with urethane prepolymer 1, and the remainder is plasticizer D added later, etc.

With regard to the urethane prepolymer 1 used in Example 27, a urethane prepolymer was prepared in the same manner as above (Preparation of urethane prepolymer 1 ^* ) except that 160 g of diisononyl phthalate (DINP) was used instead of 160 g of diisononyl adipate (DINA), to synthesize urethane prepolymer 1 containing 1.95 mass % of isocyanate groups, and a mixture of the above urethane prepolymer 1 and diisononyl phthalate as a plasticizer was obtained.
In the above mixture, the content of diisononyl phthalate was 10.9 parts by mass per 100 parts by mass of the pure urethane prepolymer 1.

<Production of Adhesive Composition>
The components in Table 1 below were used in the amounts (parts by mass) shown in the table and mixed in a continuous mixer (Dalton Continuous Kneader Continuous Mixer) to prepare compositions.
In the following tables, DBP stands for dibutyl phthalate oil absorption, and its unit is ml/100 g (cm ³ /100 g).
In addition, the amount of urethane prepolymer in each table is the net amount of urethane prepolymer.

[evaluation]
The adhesive compositions prepared as described above were subjected to the following evaluations, and the results are shown in Table 1.

[Heat stability during manufacturing: Heat generation during mixing]
As described above, the components in Table 1 were used in the compositions (parts by mass) shown in the same table, and these were mixed in the above-mentioned continuous mixer at a mixing speed of 4 L/min, and the temperature of the mixture was measured.
Evaluation criteria for thermal stability during production When the temperature measured as described above was 100° C. or lower, the adhesive composition was evaluated as having excellent thermal stability during production and was indicated with an “O” mark.
On the other hand, when the temperature measured as described above exceeded 100° C., the adhesive composition was evaluated as having poor thermal stability during production, and this was indicated by “×”.
The results are shown in the "Heat generation during mixing" column.

[Ease of use]
Evaluation criteria for workability during use In the present invention, when the viscosity described below was 55 to 85 and the evaluation results for triangular bead retention, deep curing ability, and foaming upon curing were all rated as "good," the adhesive composition was evaluated as having excellent workability during use.
On the other hand, when the viscosity was outside the range of 55 to 85, or when any of the evaluation results of triangular bead retention, deep curing ability, and foaming upon curing was ×, the adhesive composition was evaluated as having poor workability during use.

(viscosity)
The SOD viscosity (initial viscosity) of each of the adhesive compositions produced as described above was measured at 60° C. using a pressure viscometer (ASTM D 1092) in accordance with JASO M338-89.
The above measurement results are shown in the "Viscosity" column.

Viscosity Evaluation Criteria When the viscosity measured as described above was 55 to 85, the viscosity of the obtained composition was evaluated to be in the appropriate range.
On the other hand, when the viscosity measured as described above was less than 55 or more than 85, the viscosity of the obtained composition was evaluated as not being in the appropriate range.

[Triangular bead retention]
Each adhesive composition prepared as described above was heated to 60° C. and extruded onto a glass plate in the form of a right-angled triangular bead having a base side of 6 mm and a height of 10 mm into a strip (length 15 cm). The glass plate was then set up vertically (at an angle of 90°) so that the face to which the 10 mm-high side of the strip-shaped composition belonged was horizontal and located on the upper surface of the strip-shaped composition, the glass plate was fixed, and while the glass plate was held vertically, it was left for 30 minutes under conditions of 20° C. and 65% relative humidity.
Within 30 minutes after the glass plate was turned vertical, the distance h (mm) that the apex of the right triangle of each adhesive composition sagged downward was measured, and this value was used to evaluate triangular bead retention.

Evaluation Criteria for Triangular Bead Retention When the distance h measured as described above was 2 mm or less, the triangular bead retention was evaluated as excellent, and this was indicated by "O".
On the other hand, when the distance h exceeded 2 mm, the triangular bead retention was evaluated as poor, and this was indicated by "X."

[Deep curing]
A polyethylene frame (frame size: 50 mm x 50 mm x 12.5 mm) was prepared, and each adhesive composition prepared as described above was heated to 60°C and poured into the frame up to the height of the frame while being careful not to let air bubbles get in, and the surface of the adhesive composition at the top that was in contact with the air was smoothed to prepare a test specimen. This test specimen was left under conditions of 23°C and 50% humidity for 60 hours.
After 60 hours had elapsed, the center of the test specimen was cut perpendicular to the upper surface exposed to the atmosphere (the surface facing the air), uncured adhesive composition was removed, and the cross section of the obtained cured product was visually observed.

Criteria for evaluation of deep curability When the entire cross section of the cured product was cured, the deep curability was evaluated as excellent and indicated by "◯".
On the other hand, when there was an uncured portion on the cross section of the cured product, it was evaluated as having poor deep curability and this was indicated by "X".

[Foamability during curing]
Each adhesive composition manufactured as described above and heated to 60°C was applied to one of two glass plates coated with a glass primer (product name: Hamatite G (MS-90)) in a △ bead of △8 mm × 12 mm and a length of 15 mm, and the remaining glass plate was placed on top of it and pressed until the thickness of the adhesive composition was 3 mm, and then it was left at 20°C for 3 hours under 65% RH, immersed in 40°C warm water for 72 hours, removed, and dried for 1 hour. This was used as a test specimen to check whether there was any air retention at the adhesive interface or inside the adhesive. If there was no air (foaming), it was evaluated as having good foaming properties when cured, and this was displayed as "◯". On the other hand, if there was air, it was evaluated as having poor foaming properties when cured, and this was displayed as "X".

[Stability during use: constant flow pump heat generation]
Each adhesive composition produced as described above was used in a constant flow pump (a trochoidal pump manufactured by Yokohama Giken Co., Ltd.) which was operated for 6 hours (test conditions: piping pressure 20 MPa, rotation speed = 1000 rpm), and then the temperature of the pump surface was measured.

Evaluation criteria for stability during use When the temperature measured as described above was 75° C. or lower, the adhesive composition was evaluated as having excellent stability during use and was indicated with an “O” mark.
On the other hand, when the temperature measured as described above exceeded 75° C., the adhesive composition was evaluated as having poor stability during use, and this was indicated by "X."
The results are shown in the column "Constant flow pump heat generation."

[Physical properties of the obtained cured product (initial properties and properties after aging)]
In the present invention, the physical properties of the cured product obtained from the adhesive composition were evaluated as excellent when the tensile modulus, as described below, was 1.2 MPa or more, the elongation at break was 200% or more, and the shear strength retention after aging was 60% or more.
On the other hand, when the tensile modulus was less than 1.2 MPa, the elongation at break was less than 200%, or the shear strength retention after aging was less than 60%, the physical properties of the cured product obtained from the adhesive composition were evaluated as poor.

<Evaluation of tensile modulus and elongation at break>
(Preparation of samples for evaluating tensile modulus and elongation at break)
Each adhesive composition produced as described above was cured for 336 hours under conditions of 20° C. and 65% RH, and a dumbbell-shaped No. 3 sample with a thickness of 2 mm was cut out from the resulting cured product.

(Tensile test)
Using the samples prepared as described above, a tensile test was performed at a tensile speed of 500 mm/min at 23° C. to measure the tensile modulus (unit: MPa) and elongation at break (elongation at break, unit: %) in accordance with JIS K 6251. The tensile modulus was calculated from two stresses of 10 N and 20 N.

Tensile Modulus When the tensile modulus was 1.2 MPa or more, the hardness of the resulting cured product was high, that is, the rigidity was high, and this was evaluated as being preferable.
On the other hand, when the tensile modulus was less than 1.2 MPa, the hardness of the resulting cured product was evaluated as being low.

Elongation at break When the elongation at break was 200% or more, the elongation of the resulting cured product was evaluated as excellent. In Table 1, "200<" in the "Elongation at break" column indicates that the elongation at break was 200% or more.
On the other hand, when the elongation at break was less than 200%, the elongation of the resulting cured product was evaluated as being low.

<Evaluation of Shear Strength Retention Rate>
(Preparation of samples for evaluating shear strength retention rate)
Each adhesive composition produced as described above was heated to 60°C and applied to glass (25 mm width x 120 mm length x 5 mm thickness; primed; primer MS-90, product name, Yokohama Rubber Co., Ltd.), and a painted plate (O-1810, product name, Nippon Paint Co., Ltd.; no primer; same size as the glass) was laminated on top at 10 mm lengthwise to make the adhesive composition 5 mm thick. The laminate was cured for 1 week under conditions of 20°C and 65% RH to obtain initial test pieces for shear strength.
Next, the initial test piece was placed under a condition of 80° C. for 2 weeks, and then subjected to a vibration test with an amplitude of 10% and 10 Hz for 1 week to obtain an aged test piece.

(Measurement of shear strength)
The shear strength of the initial test piece and the aged test piece was measured under conditions of 23°C in accordance with JIS K6850:1999 (Test method for tensile shear adhesive strength between adhesive and rigid adherend), to obtain the initial shear strength and the shear strength after aging, respectively.

(Evaluation Criteria for Shear Strength Retention Rate)
The above initial shear strength and shear strength after aging were applied to the following formula to calculate the shear strength retention rate (%).
Shear strength retention rate (%) = shear strength after aging / initial shear strength × 100
When the shear strength retention was 60% or more, the strength of the cured product after aging (aging due to heat and vibration) was evaluated to be excellent.
On the other hand, when the shear strength retention was less than 60%, the strength of the cured product after aging was evaluated as poor.

[Adhesiveness: Heat-resistant adhesiveness]
(Preparation of samples for evaluating adhesion)
A sheet of glass (25 mm x 120 mm x 5 mm, primer-treated, primer is MS-90, manufactured by Yokohama Rubber Co., Ltd.) was prepared as an adherend. Each of the adhesive compositions was heated to 60°C and then heated to room temperature ( The adhesive was applied to the glass at 23° C. (△8 mm×12 mm×10 cm length), and a painted board (product name O-1810, manufactured by Nippon Paint Co., Ltd., no primer) was also similarly applied, and the glass and the The adhesive layer was pressed against a coated plate until the thickness of the adhesive layer composition reached 3 mm, and the adhesive layer was cured at 20° C. and 65% RH for 7 days. The coated plate test pieces were then left to stand at 100° C. for 4 weeks to prepare heat-resistant adhesion test pieces.

(Manual peeling test)
The heat-resistant adhesive test pieces obtained as described above were subjected to a manual peel test using a cutter knife.
When the adhesive layer as a whole underwent cohesive failure as a result of the manual peel test, the adhesive property (particularly heat-resistant adhesive property) was evaluated as excellent and this was indicated by "◯".
On the other hand, when interfacial peeling was confirmed as a result of the manual peeling test, the adhesion was evaluated as poor and this was indicated by "X".

Details of each component shown in Table 1 are as follows.
[Urethane prepolymer]
Urethane prepolymer 1: Each urethane prepolymer 1 prepared as above

〔Carbon black〕
Carbon black 1: Product name Asahi Thermal, manufactured by Asahi Carbon Co., Ltd., DBP oil absorption amount 28 ml/100 g, FT class. Carbon black 1 does not fall under either carbon black A or B. The same applies to carbon blacks 2 to 4 described below.
Carbon black A: Product name CSX682, manufactured by Cabot Specialty Chemicals, DBP oil absorption 34 ml/100 g
Carbon black 2: Product name: Seast TA, manufactured by Tokai Carbon Co., Ltd., DBP oil absorption: 42 ml/100 g

Carbon black 3: Product name HTC#S, manufactured by Nippon Steel Carbon Co., Ltd., DBP oil absorption 72 ml/100 g
Carbon black B: Product name ELFTEX 460, manufactured by Cabot Specialty Chemicals, DBP oil absorption 102 ml/100 g
Carbon black 4: Trade name Niteron #300, manufactured by Shinnikka Carbon Co., Ltd., DBP oil absorption 115 ml/100 g, ISAF grade

[White filler C]
White filler C: heavy calcium carbonate. 50% cumulative particle size 8.5 μm (Super S, Maruo Calcium Co., Ltd.) Surface untreated

[Plasticizer D]
Plasticizer D1: Diisononyl adipate (DINA)
Plasticizer D2: Diisononyl phthalate (DINP)

[Modified product E]
Modified product E1: HDI vulette product represented by the above formula (7) (D165N, manufactured by Mitsui Takeda Urethane Co., Ltd.)
Modified product E2: HDI isocyanurate represented by the above formula (8) (D170N, manufactured by Mitsui Takeda Urethane Co., Ltd.)

[Thermoplastic polyester F]
Thermoplastic polyester F1: A polyester in which isocyanatohexyl groups are bonded to both ends of a thermoplastic polyester made from 1,6-hexanediol and sebacic acid.
(Preparation of Thermoplastic Polyester F1)
Thermoplastic polyester diol made from 1,6-hexanediol and sebacic acid (product name Teslac 2461, manufactured by Showa Denko Materials Co., Ltd.; melting point 57-59°C, weight average molecular weight 2000) and 1,6-hexanediisocyanate (HDI) were used in amounts such that the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of the thermoplastic polyester polyol was 2.0, and these were reacted under conditions of 80°C to produce thermoplastic polyester F1.

(Comparative) Thermoplastic polyester polyol: Thermoplastic polyester diol made from 1,6-hexanediol and sebacic acid. Product name: URIC SE-2606, manufactured by Ito Oil Mills. Melting point: 66-68°C, weight average molecular weight: 2500
(Comparison) Aliphatic diisocyanate: 1,6-hexane diisocyanate

Catalyst + Plasticizer D3: A mixture of the following catalysts (9) to (12) and (13) Plasticizer D3 (total 3 parts by mass)
(9) Dioctyltin dilaurate: Neostan 810 (Nitto Kasei) 0.01 parts by weight (10) Bis(2,2-morpholinoethyl)ether: DMDEE (Huntsman) 0.12 parts by weight (11) Bis(dimethylaminoethyl)ether: BL-19 (Evonik) 0.05 parts by weight (12) Dimethylaminoethylmorpholine: X-DM (Evonik) 0.1 parts by weight (13) Plasticizer D3: Diisononyl phthalate (DINP) 2.72 parts by weight

As is clear from the results shown in Table 1, at least Comparative Examples 1 and 2 in which a was smaller than the specified range had poor adhesiveness (heat-resistant adhesiveness).
Comparative Examples 3 to 5, in which a+3b was outside the specified range, had poor workability (viscosity or triangular bead retention) during use.
At least Comparative Examples 6 to 8, in which a was greater than the specified range, had poor thermal stability during production.
Comparative Example 9, in which c was below the prescribed range, had poor workability (deep portion curing) during use.
In Comparative Example 10, in which c was greater than the prescribed range, the physical properties (elongation at break) and stability during use of the resulting cured product were poor.
Comparative Example 11, in which d was smaller than the prescribed range, had poor thermal stability during production and poor workability (viscosity, foaming property upon curing) during use.
Comparative Example 12, in which d was greater than the prescribed range, had poor workability (triangular bead retention) and poor adhesiveness (heat-resistant adhesiveness) during use.
In Comparative Example 13, in which e was below the prescribed range, the physical properties (tensile modulus of elasticity) and adhesiveness (heat-resistant adhesiveness) of the obtained cured product were poor.
Comparative Example 14, in which e was greater than the prescribed range, had poor workability during use (foamability upon curing) and poor physical properties of the resulting cured product (elongation at break).
Comparative Example 15, in which a, b, and a+3b were outside the specified ranges, had poor thermal stability during production, poor workability (viscosity) during use, and poor physical properties of the resulting cured product (elongation at break, shear strength retention).
Comparative Examples 16 and 17, in which b and a+3b were outside the prescribed range, had poor workability during use (ability to retain triangular beads) and the like.
Comparative Example 18, which did not contain carbon black A but instead contained carbon black 1 having a lower DBP oil absorption than carbon black A, had poor thermal stability during production and poor physical properties (elongation at break) of the resulting cured product.
Comparative Example 19, which did not contain carbon black A but contained carbon black 2 having a DBP oil absorption slightly higher than that of carbon black A, had poor adhesion (heat-resistant adhesion).
Comparative Example 20, which did not contain carbon black B but instead contained carbon black 3, which has a slightly lower DBP oil absorption than carbon black B, had poor workability during use (triangular bead retention, foaming property during curing) and poor physical properties of the obtained cured product (elongation at break).
Comparative Example 21, which did not contain carbon black B but instead contained carbon black 4 having a DBP oil absorption greater than that of carbon black B, had poor workability (viscosity) during use.
Comparative Example 22, in which b was outside the specified range and a+3b was greater than the specified range, and Comparative Example 23, in which a+3b was greater than the specified range, had poor workability (viscosity) during use.
Comparative Example 24, in which a+3b was smaller than the predetermined range, had poor workability (triangular bead retention) during use.
Comparative Example 25, which did not contain carbon black B or thermoplastic polyester F, was poor in workability during use (viscosity, triangular bead retention) and in the physical properties (tensile modulus) of the resulting cured product.
Comparative Example 26, which did not contain thermoplastic polyester F but contained thermoplastic polyester polyol and aliphatic diisocyanate instead, had poor workability during use (foamability upon curing) and poor physical properties of the resulting cured product (elongation at break).

In contrast, the urethane adhesive composition of the present invention has excellent thermal stability during production, workability and stability during use, and the physical properties and adhesiveness of the resulting cured product.

Claims (6)

A urethane prepolymer;
Carbon black A having a dibutyl phthalate oil absorption of 30 to 40 ml/100 g;
Carbon black B having a dibutyl phthalate oil absorption of 98 to 108 ml/100 g;
White filler C;
A plasticizer D; and
A modified aliphatic diisocyanate E;
a thermoplastic polyester F having a plurality of aliphatic hydrocarbon groups to which isocyanate groups are bonded;
A catalyst;
the plasticizer D comprises a phthalate ester and/or an adipate ester,
A one-part moisture-curing urethane adhesive composition that satisfies all of the following (1) to (6): hereinafter, modified product E does not have an ester bond.
(1) 25≦a≦35
(2) 55≦b≦75
(3) 197≦a+3b≦251
(4) 30≦c≦35
(5) 35≦d≦45
(6) 2.5≦e≦3.7
In the above (1) and (3), a represents the content of the carbon black A relative to 100 parts by mass of the urethane prepolymer,
In the above (2) and (3), b represents the content of the carbon black B relative to 100 parts by mass of the urethane prepolymer,
In the above (4), c represents the content of the white filler C relative to 100 parts by mass of the urethane prepolymer,
In the above (5), d represents the content of the plasticizer D relative to 100 parts by mass of the urethane prepolymer,
In the formula (6), e represents the content of the modified substance E relative to 100 parts by mass of the urethane prepolymer,
The units of a to e are parts by mass. The urethane adhesive composition according to claim 1, wherein the melting point of the thermoplastic polyester polyol constituting the thermoplastic polyester F is 55 to 65°C. The urethane adhesive composition according to claim 1 or 2, wherein in the thermoplastic polyester F, the aliphatic hydrocarbon group to which the isocyanate group is bonded is derived from an aliphatic diisocyanate. The urethane adhesive composition according to any one of claims 1 to 3, wherein the content f of the thermoplastic polyester F is 3 to 8 parts by mass per 100 parts by mass of the urethane prepolymer. The urethane adhesive composition according to any one of claims 1 to 4, wherein the modified product E includes a vuret product of hexamethylene diisocyanate and/or an isocyanurate product of hexamethylene diisocyanate. The urethane adhesive composition according to any one of claims 1 to 5, wherein the white filler C contains calcium carbonate.