JP2020164635A - Polyurethane-based adhesive formation composition and adhesive - Google Patents

Abstract

To provide a polyurethane-based adhesive formation composition and adhesive that exhibit excellent adhesive strength in a short time at room temperature and has excellent high-temperature adhesiveness.SOLUTION: A polyurethane-based adhesive formation composition, containing a hydroxyl group-terminated curing agent (A) and isocyanate group-terminated polyisocyanate (B), and in which the hydroxyl group-terminated curing agent (A) contains a tertiary amino group-containing diol (a1) represented by the formula (I), and a polyol (a2) having an average functional group number of 3 or more, the content of the tertiary amino group-containing diol (a1) in the polyurethane-based adhesive formation composition is 0.04 mmol/g or more and 1.2 mmol/g or less, and the content of the polyol (a2) is 0.2 mol or more and 9.0 mol or less for 1 mol of the tertiary amino group-containing diol (a1): In the formula, R1 each independently represents a linear alkylene group having 1 to 4 carbon atoms, and R2 represents an alkyl group having 1 to 4 carbon atoms.SELECTED DRAWING: None

Description

The present invention relates to polyurethane-based adhesive forming compositions and adhesives.

In recent years, in the fields of automobiles and aircraft, weight reduction has been promoted in order to improve fuel efficiency, and there is an active movement to replace metal with lighter aluminum. Therefore, there is a demand for a high-performance adhesive that can firmly bond aluminum to each other.

Here, urethane-based adhesives are widely used for adhesive fixing of fibers-reinforced plastics (Fiber Reinforced Plastics; hereinafter referred to as FRP) and metals. For example, Patent Document 1 describes a prepolymer obtained by reacting a polyisocyanate with a high molecular weight polyol, a first liquid containing a specific filler as a constituent component and containing a predetermined amount of the filler; and two types of polyols having different molecular weights. A urethane adhesive composition comprising a catalyst and a second liquid containing; and containing each polyol in a predetermined ratio is disclosed. According to Patent Document 1, this urethane adhesive composition adheres steel plates to each other and FRP to each other at room temperature, and exhibits high adhesiveness.

International Publication No. 2009/047962

However, the urethane adhesive composition according to Patent Document 1 is inferior in productivity because it takes 24 hours or more to cure.
Further, for example, in the case of an automobile assembled by an assembly line, it is necessary to have room temperature curability that can exhibit high adhesive force after bonding materials at room temperature, and it is used in a painting process performed at a high temperature of 150 ° C. to 200 ° C. High temperature adhesiveness that can withstand is required.
Therefore, one embodiment of the present invention is directed to providing a polyurethane-based adhesive forming composition and an adhesive that exhibit excellent adhesive strength in a short time at room temperature and have excellent high-temperature adhesiveness. There is.

One embodiment of the present invention is shown in (i) to (iv) below.
(I) Hydroxyl-terminated curing agent (A) and
A polyurethane-based adhesive forming composition containing an isocyanate group-terminated polyisocyanate (B).
The hydroxyl group terminal curing agent (A) is
A tertiary amino group-containing diol (a1) represented by the formula (I) and
Containing a polyol (a2) having an average functional group number of 3 or more,
The content of the tertiary amino group-containing diol (a1) is 0.04 mmol / g or more and 1.2 mmol / g or less in the polyurethane-based adhesive forming composition.
Polyurethane-based adhesive forming composition in which the content of the polyol (a2) is 0.2 mol or more and 9.0 mol or less with respect to 1 mol of the tertiary amino group-containing diol (a1):

During the ceremony
R ¹ independently represents a linear alkylene group having 1 to 4 carbon atoms.
R ² represents an alkyl group having 1 to 4 carbon atoms.

(Ii) 2 both R ¹ are identical, polyurethane adhesive-forming composition according to (i).

(Iii) The polyurethane-based adhesive forming composition according to (i) or (ii), wherein the content of triethylenediamine in the polyurethane-based adhesive forming composition is 0% by mass or more and 0.04% by mass or less.

(Iv) An adhesive containing the polyurethane-based adhesive forming composition according to any one of (i) to (iii) and the inorganic filler (C).

According to one embodiment of the present invention, it is possible to provide a polyurethane-based adhesive forming composition and an adhesive which exhibit excellent adhesive strength in a short time at room temperature and have excellent high-temperature adhesiveness.

It is a graph which shows the temperature change of the storage elastic modulus E'of Example 3 and Reference Examples 1-3.

The present inventors have further studied the urethane adhesive composition according to Patent Document 1. Then, it was found that the urethane adhesive composition according to Patent Document 1 was not assumed to be exposed to a high temperature and was not at a practically satisfactory level.
On the other hand, although the detailed mechanism is unknown, the present inventors have a polyurethane-based adhesive forming composition containing a predetermined amount of a tertiary amino group-containing diol (a1) represented by the formula (I) described later. As a result, it was found that excellent room temperature adhesiveness is exhibited in a short time, and the decrease in adhesiveness is suppressed under high temperature conditions.

Hereinafter, exemplary embodiments for carrying out the present invention will be described in detail.
[Polyurethane-based adhesive forming composition]
The polyurethane-based adhesive forming composition according to an embodiment of the present invention is
Hydroxyl-terminated curing agent (A) and
Containing isocyanate group-terminated polyisocyanate (B)
The hydroxyl group terminal curing agent (A) is
A tertiary amino group-containing diol (a1) represented by the formula (I) and
Containing a polyol (a2) having an average functional group number of 3 or more,
The content of the tertiary amino group-containing diol (a1) is 0.04 mmol / g or more and 1.2 mmol / g or less in the polyurethane-based adhesive forming composition.
Polyurethane-based adhesive forming composition in which the content of the polyol (a2) is 0.2 mol or more and 9.0 mol or less with respect to 1 mol of the tertiary amino group-containing diol (a1):

During the ceremony
R ¹ independently represents a linear alkylene group having 1 to 4 carbon atoms.
R ² represents an alkyl group having 1 to 4 carbon atoms.

[Hydroxyl terminated hardener (A)]
The hydroxyl-terminated curing agent (A) is
A tertiary amino group-containing diol (a1) represented by the formula (I) and
Includes polyol (a2) with an average cardinal number of 3 or more:

During the ceremony
R ¹ independently represents a linear alkylene group having 1 to 4 carbon atoms.
R ² represents an alkyl group having 1 to 4 carbon atoms.

[[Diol (a1)]]
Specific examples of R ¹ include a methylene group, an ethylene group, a trimethylene group, and a tetramethylene group. R ¹ may be the same or different. When R ¹ is the same, the tertiary amino group-containing diol (a1) can be easily produced and the cost is low, which is preferable.
R ² may be a linear alkyl group or a branched alkyl group, and specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and the like. Examples thereof include sec-butyl group and t-butyl group.

Specific examples of the tertiary amino group-containing diol (a1) include N-methyldiethanolamine, N-ethyldiethanolamine, N-butyldiethanolamine, N-methyldipropanolamine, N-methyldibutanolamine and the like. These may be used alone or in combination of two or more. In particular, N-methyldiethanolamine is preferable from the viewpoint of resin physical properties.

The content of the diol (a1) having a tertiary amino group is 0.04 mmol / g or more and 1.2 mmol / g or less, preferably 0.1 mmol / g or more in the polyurethane-based adhesive forming composition. It is 1 mmol / g or less, more preferably 0.15 mmol / g or more and 1.0 mmol / g or less. When the content of the diol (a1) having a tertiary amino group is less than 0.04 mmol / g, it takes a long time to cure at room temperature, and when it exceeds 1.2 mmol / g, the curing rate is high and the adherend is formed. The transfer rate of

[[Polyprethane (a2)]]
Examples of the polyol (a2) having an average number of functional groups of 3 or more include glycerin, trimethylolpropane, pentaerythritol, N, N-bishydroxypropyl-N-hydroxyethylamine, triethanolamine, triisopropanolamine, and a monomer of an ethylenediaminepropylene oxide modified product. Polymer, monomeric polyol of trimethylolpropane propylene oxide modified product, pentaerythritol propylene oxide modified product; and ε-caprolactone, β-butyrolactone, γ-butyrolactone, using polyols such as glycerin, trimethylolpropane, pentaerythritol, etc. as initiators. Examples thereof include polycaprolactone polyols obtained by ring-opening addition of cyclic esters such as γ-valerolactone and δ-valerolactone. These may be used alone or in combination of two or more.

The content of the polyol (a2) having an average functional group number of 3 or more is 0.2 mol or more and 9.0 mol or less, preferably 0.3 mol or more, with respect to 1 mol of the diol (a1) having a tertiary amino group. It is 0 mol or less, more preferably 0.7 mol or more and 3.0 mol or less. When the content exceeds 9.0 mol, the diol (a1) having a tertiary amino group is less than the polyol (a2) having an average functional group number of 3 or more, and it does not sufficiently cure at room temperature. When the content is less than 0.2 mol, the amount of the diol (a1) having a tertiary amino group is large with respect to the polyol (a2) having an average functional group number of 3 or more, the pot life is very short, and the wettability is ensured. It cannot be done and the adhesive strength becomes low.

[[Other polyols]]
A polyol having a tertiary amino group (a1) and a polyol (a2) having an average functional group number of 3 or more can be used in combination with a polyol having an average functional group number of 2 or less.
Examples of the polyol having an average functional group number of 2 or less include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol. 1,5-Pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptan, diethyleneglycol, di Alkyl such as propylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, methylglycidyl ether, etc. Examples thereof include polyether polyols obtained by ring-opening polymerization of aryl glycidyl ethers such as glycidyl ethers and phenyl glycidyl ethers, and cyclic ether monomers such as tetrahydrofuran.

In addition, polyols having two or less carbonate bonds, ester bonds, ether bonds, etc., such as polymer polyols, polycarbonate polyols, polyester polyols, and polyether polyols, can be mentioned. Among these, a polycarbonate polyol is preferable from the viewpoint of heat resistance, and a liquid polycarbonate polyol that can be handled in a liquid state at room temperature is particularly preferable.

Examples of the polycarbonate polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. , 1,6-Hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylol heptane, diethylene glycol, dipropylene glycol, neopentyl glycol , Cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, glycerin, trimethylolpropane, dimer acid diol, ethylene oxide or propylene oxide adduct of bisphenol A, bis (β-hydroxyethyl) benzene, xylylene With one or more of polyols such as glycols; dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, alkylene carbonates such as ethylene carbonate and propylene carbonate, diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, diphenanthryl carbonate, Examples thereof include those obtained from one or more kinds of carbonates such as diindanyl carbonate; and dealcoholization reaction and dephenolization reaction. These may contain one kind, or may contain two or more kinds.

Examples of polyester polyols include phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartrate acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimeric acid, suberic acid, glutaconic acid, azelaic acid, and sebacic acid. , 1,4-Cyclohexyldicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α, β-diethylsuccinic acid, maleic acid, dicarboxylic acids such as fumaric acid or these. With one or more of the anhydrides, etc .; ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptan, diethylene glycol, dipropylene glycol , Neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, glycerin, trimethylolpropane, diol dimerate, ethylene oxide or propylene oxide adduct of bisphenol A, bis (β-hydroxyethyl) Examples thereof include those obtained by a condensation polymerization reaction with one or more kinds of benzene, xylylene glycol and the like. Further, it is also possible to use a polyester-amide polyol obtained in place of a low molecular weight polyamine such as hexamethylenediamine, isophoronediamine or monoethanolamine or a low molecular weight amino alcohol. These may contain one kind, or may contain two or more kinds.

Examples of the polyether polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentane. Diol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptan, diethylene glycol, dipropylene glycol, neopentyl Low molecular weight polyols such as glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol; or ethylenediamine, propylenediamine , Toluenediol, metaphenylenediamine, diphenylmethanediamine, xylylene diamine and other low molecular weight polyamines; etc.; starting with a compound having two active hydrogen groups such as ethylene oxide, propylene oxide, butylene oxide and the like. Obtained by ring-opening polymerization of polyether polyols obtained by addition polymerization of alkylene oxides, alkyl glycidyl ethers such as methyl glycidyl ether, aryl glycidyl ethers such as phenyl glycidyl ether, and cyclic ether monomers such as tetrahydrofuran. Polyether polyols can be mentioned. These may contain one kind, or may contain two or more kinds.

The method for producing the hydroxyl group terminal curing agent (A) is not particularly limited, and a known and publicly available method can be applied. For example, after a polyol having an average functional group number of 2 or less is put into a stirring container, a tertiary amino group-containing diol (a1) and a polyol having an average functional group number of 3 or more (a2) are maintained while keeping the temperature inside the container at 40 to 70 ° C. ) Is added and stirred. Subsequently, the hydroxyl group terminal curing agent (A) can be obtained by stirring and mixing for about 0.5 to 2 hours while maintaining the temperature in the stirring container at 40 ° C. to 70 ° C. In addition, a catalyst or other additives can be added as needed during stirring and mixing.

[Isocyanate group-terminated polyisocyanate (B)]
The isocyanate group-terminated polyisocyanate (B) is an isocyanate group-terminated urethane obtained by modifying an unmodified isocyanate (b1) such as an aliphatic isocyanate, an alicyclic isocyanate, an aromatic isocyanate, or an aromatic aliphatic isocyanate with a polyol. As long as it is a prepolymer, there are no restrictions. Further, if necessary, additives such as a reaction control agent and an antioxidant may be added. Of these, an isocyanate group-terminated polyisocyanate (B) obtained by reacting an aromatic isocyanate with a polyol (b2) having an average functional group number of 2 is preferable from the viewpoint of reactivity and viscosity. Since the isocyanate group-terminated polyisocyanate (B) used in the adhesive is liquid at room temperature, the unmodified isocyanate (b1) used for modification is particularly preferably liquid at room temperature.

The method for producing the isocyanate group-terminated polyisocyanate (B) is not particularly limited, and a known and publicly available method can be applied. For example, after putting a 4,4'-diphenylmethane diisocyanate / 2,4'-diphenylmethane diisocyanate mixture into a stirring container, a bifunctional or trifunctional polyol containing no amino group while maintaining the temperature inside the container at 40 to 70 ° C. And stir. Subsequently, the isocyanate group-terminated polyisocyanate (B) can be obtained by advancing the urethanization reaction for about 2 to 5 hours while keeping the temperature inside the stirring vessel at 70 to 90 ° C.

<Alphatic isocyanate>
Examples of the aliphatic isocyanate include hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, lysine diisocyanate, trioxyethylene diisocyanate, ethylene diisocyanate, and trimethylene. Diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, 2,2'-dimethylpentane diisocyanate, 2,2,4-trimethylhexane diisocyanate, decamethylene diisocyanate, butene diisocyanate, 1,3-butadiene-1,4-diisocyanate, 2, 4,4-trimethylhexamethylene diisocyanate, 1,6,11-undecantryisocyanate, 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanatemethyloctane, 2,5,7-trimethyl- 1,8-Diisocyanate-5-Isocyanate methyl octane, bis (isocyanate ethyl) carbonate, bis (isocyanate ethyl) ether, 1,4-butylene glycol dipropyl ether-α, α'-diisocyanate, lysine diisocyanate methyl ester, 2- Examples thereof include isocyanate ethyl-2,6-diisocyanate hexanoate and 2-isocyanatepropyl-2,6-diisocyanate hexanoate.

<Alicyclic isocyanate>
Examples of the alicyclic isocyanate include isophorone diisocyanate, cyclohexyldiisocyanate, bis (isocyanatemethyl) cyclohexane, dicyclohexylmethane diisocyanate, methylcyclohexanediisocyanate, dicyclohexyldimethylmethanediisocyanate, 2,2'-dimethyldicyclohexylmethanediisocyanate, and bis (4-isocyanate-). n-butylidene) pentaerythritol, hydride diisocyanate hydrogenated dimerate, 2-isocyanatemethyl-3- (3-isocyanatepropyl) -5-isocyanatemethyl-bicyclo [2.2.1] -heptane, 2-isocyanate Methyl-3- (3-isocyanatepropyl) -6-isocyanatemethyl-bicyclo [2.2.1] -heptane, 2-isocyanatemethyl-2- (3-isocyanatepropyl) -5-isocyanatemethyl-bicyclo [2. 2.1] -Heptane, 2-Isocyanatemethyl-2- (3-Isocyanatepropyl) -6-Isocyanatemethyl-bicyclo [2.2.1] -Heptane, 2-Isocyanatemethyl-3- (3-Isocyanatepropyl) -5- (2-Isocyanate ethyl) -bicyclo- [2.2.1] -heptane, 2-isocyanate methyl-3- (3-isocyanate propyl) -6- (2-isocyanate ethyl) -bicyclo- [2. 2.1] -Heptane, 2-isocyanatemethyl-2- (3-isocyanatepropyl) -5- (2-isocyanateethyl) -bicyclo- [2.2.1] -heptane, 2-isocyanatemethyl-2- ( 3-Isocyanatepropyl) -6- (2-Isocyanateethyl) -bicyclo- [2.2.1] -heptane, 2,5-bis (isocyanatemethyl) -bicyclo [2.2.1] -heptane, hydrogenated Examples thereof include hydrogenated diphenylmethane diisocyanate, norbornan diisocyanate, hydrogenated hydrogenated tolylene diisocyanate, hydrogenated hydrogenated xylene diisocyanate, and hydrogenated hydrogenated tetramethylxylene diisocyanate.

<Aromatic isocyanate>
Examples of the aromatic isocyanate include 2,4-tolylene diisocyanis, 2,6-tolylene diisocyanis, 2,4-tolylene diisocyanate / 2,6-tolylene diisocyanate mixture, 2,4'-diphenylmethane diisocyanate, 2, 4'-diphenylmethane diisocyanate / 4,4'-diphenylmethane diisocyanate mixture, m-xylylene diisocyanate, p-xylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2 '-Diphenylpropan-4,4'-diisocyanis, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanis, 4,4'-diphenylpropanediisocyanis, m-phenylenediocyanate, p-phenylenediocyanis, naphthylene-1, Examples thereof include 4-diisocyanis, naphthylene-1,5-diisocyanate, and 3,3'-dimethoxydiphenyl-4,4'-diisocyanate.

<Aromatic aliphatic isocyanate>
Examples of the aromatic aliphatic isocyanate include 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, 1,3- or 1,4-bis (1-isocyanato-1-methylethyl) benzene or a mixture thereof, ω. , Ω'-diisocyanato-1,4-diethylbenzene and the like.

The isocyanate group-terminated polyisocyanate (B) is preferably obtained from a polyol (b2) having an average functional group number of 2 from the viewpoint of ease of handling after prepolymerization.

Examples of the polyol (b2) include polyols having two or more ether bonds, ester bonds, carbonate bonds, etc., such as polyether polyols, polycarbonate polyols, and polyester polyols.

Examples of the polyether polyol, the polycarbonate polyol, and the polyester polyol include the same ones as the polyether polyol, the polycarbonate polyol, and the polyester polyol mentioned as other polyols of the hydroxyl-terminated curing agent (A).

Among these, a polyether polyol (polytetramethylene glycol) obtained by ring-opening polymerization of a cyclic ether monomer such as tetrahydrofuran is preferable from the viewpoint of exhibiting excellent physical properties.

[catalyst]
A catalyst can also be used for the purpose of accelerating the reaction between the hydroxyl group-terminated curing agent (A) and the isocyanate group-terminated polyisocyanate (B). When the content of the catalyst is 0.05% by mass or less in the polyurethane-based adhesive forming composition, the decrease in elastic modulus of the resin at a high temperature (150 to 200 ° C.) can be further suppressed, and more excellent high-temperature adhesion can be achieved. It is particularly preferable because it exhibits properties.
Examples of the catalyst include isocyanurate-forming catalysts, urethanization catalysts and the like, and specific examples are as shown below.

<Isocyanurate catalyst>
Examples of the isocyanurate-forming catalyst include triethylamine, N-ethylpiperidine, N, N'-dimethylpiperazine, N-ethylmorpholine, tertiary amines such as Mannich base of phenol compound, potassium acetate and the like. In addition, these isocyanurate-forming catalysts can be used alone or in combination of two or more.

<Urethane catalyst>
As the urethanization catalyst, a known catalyst can be appropriately selected and used, and examples thereof include an amine catalyst, an imidazole catalyst, and a metal catalyst catalyst.

<< Amine-based catalyst >>
Examples of amine-based catalysts include triethylenediamine, 2-methyltriethylenediamine, N, N, N', N'-tetramethylethylenediamine, N, N, N', N'-tetramethylpropylenediamine, N, N, N. ', N', N'-pentamethyldiethylenetriamine, N, N, N', N', N'-pentamethyl- (3-aminopropyl) ethylenediamine, N, N, N', N', N'-pentamethyl Examples thereof include dipropylene triamine, N, N, N', N'-tetramethylhexamethylenediamine, bis (2-dimethylaminoethyl) ether and the like.

Here, as described above, the urethane adhesive composition according to Patent Document 1 has not obtained sufficient high-temperature adhesiveness. As a result of further studies by the present inventors on this matter, the triethylenediamine (curing catalyst) contained in the urethane adhesive composition according to Patent Document 1 has some influence on other components under high temperature conditions. Therefore, the present inventors presume that sufficient high-temperature adhesiveness is not obtained.
On the other hand, in the case of the urethane adhesive composition according to the present embodiment, the adhesiveness at room temperature brought about by triethylenediamine is ensured by containing a predetermined amount of the tertiary amino group-containing diol (a1) represented by the formula (1). However, the present inventors presume that the influence of triethylenediamine on other components at high temperatures is highly suppressed.
Therefore, the content of triethylenediamine is preferably 0% by mass or more and 0.04% by mass or less, and 0% by mass or more and 0.02 by mass or more, in the urethane adhesive composition in order to exhibit more excellent adhesiveness at high temperature. It is more preferably 0% by mass or less, and particularly preferably 0% by mass.

<< Imidazole catalyst >>
Examples of the imidazole-based catalyst include 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropyl imidazole and the like.

<< Metallic catalyst >>
Examples of the metal catalyst include organic tin catalysts such as stanas diacetate, stanas dioctate, stanas diolaate, stanas dilaurate, dibutyl tin oxide, dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl tin dichloride, and dioctyl tin dilaurate. Etc. can be mentioned.

[Other additives]
If necessary, the polyurethane-based adhesive forming composition may further contain a reaction inhibitor, an antioxidant, an antifoaming agent, and the like as additives.

[adhesive]
The adhesive according to one embodiment of the present invention contains the above-mentioned polyurethane-based adhesive forming composition and the inorganic filler (C).

[Inorganic filler (C)]
Examples of the inorganic filler (C) include, but are not limited to, talc, zeolite, silica, microballoon, clay, glass balloon, carbon black and the like. These can be used alone or in combination of two or more. Of these, a combination of zeolite and talc is preferable. Zeolites have the effect of suppressing foaming, and talc has the effect of preventing dripping.

The content of the inorganic filler (C) is preferably 5 parts by mass or more and 60 parts by mass or less, and more preferably 20 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the polyurethane adhesive forming composition. is there.

As a method of kneading the inorganic filler (C) and the polyurethane-based adhesive forming composition, it can be easily mixed with a three-roll roll, a planetary mixer, a revolution rotating stirrer or the like. At this time, it is preferable to carry out in a nitrogen atmosphere for the purpose of preventing water mixing due to the outside air.

The polyurethane-based resin-forming composition and adhesive according to one embodiment of the present invention can be applied to the adhesion of various adherends. Examples of the adherend include metals such as aluminum, titanium, iron, and magnesium, plastics, and fiber reinforced resins. Among them, it is excellent in adhesiveness to aluminum, and can adhere between aluminum and aluminum, between aluminum and resin, and between aluminum and FRP. In addition, it is suitable as a structural adhesive among adhesives, and in particular, it has characteristics as a structural adhesive for automobiles, has excellent curability at room temperature in a short time, and is heat resistant to withstand high temperature coating processes. Has sex. For example, it has an adhesive strength of 2 MPa or more within 30 minutes at 10 ° C. to 30 ° C., and can maintain a rubber-like flat region even at a high temperature (150 ° C. to 200 ° C.). In the present disclosure, room temperature is, for example, 10 ° C to 30 ° C, high temperature is, for example, 150 ° C to 200 ° C, and short time is, for example, 30 minutes or less.

The present invention will be described in more detail with reference to Examples, Comparative Examples and Reference Examples, but the present invention is not limited thereto.

In a 5 L stirring container filled with nitrogen, a bifunctional polyol, a polyol (a2) having an average number of functional groups of 3 or more, and a tertiary amino group-containing diol (a1) were prepared in the formulations shown in Tables 1 to 4. Was mixed and stirred for about 1 to 3 hours while maintaining the temperature in the stirring vessel at 40 to 70 ° C. to obtain various hydroxyl-terminated curing agents (A).

Tables 1 to 4 show a mixture of 4,4'-diphenylmethane diisocyanate / 2,4'-diphenylmethane diisocyanate (b1) and a polyol (b2) having an average functional group number of 2 in a 5 L stirring container filled with nitrogen. It was added according to the mixing ratio and stirred. Then, while maintaining the temperature in the stirring vessel at 70 to 90 ° C., the urethanization reaction was carried out for about 2 to 5 hours to obtain various isocyanate-terminated polyisocyanates (B) as prepolymers.

The abbreviations of the raw materials shown in Tables 1 to 4 are as follows.
[material]
(1) Hydroxyl-terminated curing agent (A)
-"MDA"; Amino Alcohol MDA (manufactured by Nippon Emulsifier),
N-Methyldiethanolamine Hydroxyl value = 942KOHmg / g, f = 2
-"MBD"; Amino Alcohol MDA (manufactured by Nippon Emulsifier),
N-Butyldiethanolamine Hydroxyl value = 696KOHmg / g, f = 2
・ "MA-170"; Leocon MA-170 (manufactured by Lion Specialty Chemicals),
N, N-bishydroxypropyl-N-hydroxyethylamine,
Hydroxy group value = 950 KOHmg · g, f = 3
-"EDP-300"; ADEKA Polyether EDP-300 (manufactured by ADEKA),
N, N, N', N'-Tetrakis (2-Hydroxypropyl) Ethylenediamine,
Hydroxy group value = 760 KOHmg / g, f = 4
・ "TMP"; trimethylolpropane (manufactured by Mitsubishi Gas Chemical Company)
Trimethylolpropane, hydroxyl value = 1255KOHmg / g, f = 3
-"HD-402"; Sanniks HD-402 (manufactured by Sanyo Chemical Industries, Ltd.)
Pentaerythritol PO adduct, hydroxyl value = 560 KOHmg / g, f = 4
-"PCD-500"; KurarayPolyol C-590 (manufactured by Kuraray),
Polycarbonate polyol, hydroxyl value = 224KOHmg / g, f = 2
-"P-1000"; Adeka Polyether P-1000 (manufactured by ADEKA),
Polypropylene glycol, hydroxyl value = 112KOHmg / g, f = 2
・ "1,4-BG"; 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation)
1,4-butanediol, hydroxyl value = 1245 KOHmg / g, f = 2

(2) Isocyanate group-terminated polyisocyanate (B)
・ "NM"; Millionate NM (manufactured by Tosoh)
4,4'-diphenylmethane diisocyanate /
2,4'-Diphenylmethane diisocyanate mixture,
NCO content = 33.5%, f = 2
-"PTMG-850"; PTMG850 (manufactured by Mitsubishi Chemical Corporation),
Polytetramethylene glycol, hydroxyl value 132KOHmg / g, f = 2

(3) Urethane catalyst "TEDA"; triethylenediamine (TEDA-L33E, manufactured by Tosoh Corporation)

(4) Inorganic filler (C)
・ "Zeolite"; Zeolite A-3 (manufactured by Tosoh)
・ "Talc"; Crown Talc R (manufactured by Matsumura Sangyo Co., Ltd.)

<Preparation of adhesion test piece>
Inorganic filler (C) was added to isocyanate group-terminated polyisocyanate (B) according to the formulations shown in Tables 1 to 4, and mixed using a revolution rotation stirrer (trade name: Kakuhunter, manufactured by Photochemical Co., Ltd.). .. Then, according to the formulations shown in Tables 1 to 4, the hydroxyl-terminated curing agent (A) was mixed with a stainless steel spatula until uniform to prepare an adhesive. The obtained adhesive was uniformly applied to an aluminum plate (length 100 mm × width 25 mm × thickness 1 mm; A5052P) to prepare an adhesion test piece conforming to JIS K 6850: 1999.

<Preparation of test pieces and evaluation criteria>
(1) Room temperature curability [25 ° C x 30 minutes curing (25 ° C environmental measurement)]
An adhesive is applied to the surfaces of two aluminum plates (length 100 mm x width 25 mm x thickness 1 mm; A5052P), and the overlapping areas of the aluminum plates are bonded so that the length is 12.5 mm x width 25 mm, and this is 25. An adhesion test piece was prepared by allowing it to cure under the condition of ° C. for 30 minutes. At this time, using glass beads, the thickness of the adhesive layer was adjusted to 0.25 mm to obtain an adhesive test piece.
With respect to the adhesive test piece produced as described above, the tensile shear strength of the bonded portion was measured with a tensile tester (trade name: Autocom Universal Testing Machine AC-10kN-C, manufactured by TSE Co., Ltd.). .. This measurement was made in accordance with the tensile shear bond strength of the JIS K6850: 1999 adhesive. The measurement conditions were a temperature of 25 ° C., a distance between chucks of 111.5 mm, and a test speed of 10 mm / min.
When the tensile shear strength was 5 MPa or more, it was evaluated as "A (good)", when it was 2 MPa or more and less than 5 MPa, it was evaluated as "B (normal)", and when it was less than 2 MPa, it was evaluated as "C (defective)". The fracture interface after the adhesion test was CF = cohesive fracture and AF = interface fracture.

(2) Heat resistance of adhesive resin In order to confirm the heat resistance of the test piece (adhesive resin) after curing at 25 ° C for 16 hours, the adhesive is made of stainless steel so that it becomes an adhesive resin with a thickness of 2 mm. It was molded with a mold, and the obtained adhesive resin (measurement sample) was dynamically measured for viscoelasticity.
As the measurement sample, a strip-shaped test piece of 20 mm × 5 mm × 2 mm was used, and the initial load was 100 mN.
For dynamic viscoelasticity measurement, the storage elastic modulus at 200 ° C. (10 Hz) and the storage elastic modulus at 100 ° C. (10 Hz) are measured with a viscoelasticity measuring device (trade name: DMS-6100, manufactured by Hitachi High-Tech Science Co., Ltd.). It was measured.
FIG. 1 is a graph showing the temperature change of the storage elastic modulus E'of the measurement samples of Examples 3 and Reference Examples 1 to 3. Example 3 is shown by a solid line, Reference Example 1 is shown by a broken line, Reference Example 2 is shown by a dashed line, and Reference Example 3 is shown by a dotted line.

<Evaluation result>
(1) Room temperature curability: [Evaluated by adhesive strength (measured at 25 ° C) after 25 ° C for 30 minutes]
In the examples, all showed high room temperature curability and were good.
In Comparative Examples 1 to 4, a polyol (a2) having an average number of functional groups of 3 or more was used, but it did not contain a tertiary amino group-containing diol (a1), and its room temperature curability was insufficient for 30 minutes. Then it was poorly cured. In Comparative Examples 5 and 6, although the tertiary amino group-containing diol (a1) is contained, the polyol (a2) having an average functional group number of 3 or more is not contained, and the room temperature curability is insufficient. Although Comparative Example 7 contains a tertiary amino group-containing diol (a1), the content of the polyol (a2) having an average functional group number of 3 or more in the polyurethane-based adhesive forming composition contains a tertiary amino group. It exceeds 9.0 mol with respect to 1 mol of the diol (a1), the wettability is deteriorated, and the adhesive strength is low. In Comparative Example 8 and Comparative Example 10, the content of the tertiary amino group-containing polyol (a1) having an average functional group number of 2 exceeds 1.2 mmol / g and is excessive, and after mixing, it is immediately cured and used as an adhesive. I couldn't. In Comparative Example 9, the tertiary amino group-containing diol (a1) is contained and the catalyst is also contained, but the content of the polyol (a2) having an average functional group number of 3 or more is small, and the resin physical properties after curing are not sufficient. No, the adhesive strength is low. In Comparative Example 11, a sufficient amount of the polyol (a2) having an average functional group number of 3 or more is contained and a catalyst is also contained, but the content of the tertiary amino group-containing diol (a1) is small and the room temperature curability is high. Insufficient.

(2) Heat resistance of resin In both examples, it was confirmed that the rubber-like flat region was maintained up to high temperature and the heat resistance of the resin was high (see FIG. 1).
In Reference Examples 1 to 3, triethylenediamine (TEDA-L33E) was used as a general-purpose catalyst. In Reference Examples 1 to 3, the room temperature curability is good because it contains triethylenediamine, which is highly effective in improving the room temperature curability. However, since Reference Examples 1 to 3 contain an excessive amount of triethylenediamine, the storage elastic modulus significantly decreases from around 200 ° C. (see FIG. 1), and the storage elastic modulus at 200 ° C and 100 ° C. The storage modulus ratio of is less than 1/2, which makes it unsuitable for applications exposed to high temperatures. In particular, looking at the vicinity of 200 ° C. in FIG. 1, Reference Examples 1 and 2 do not contain the tertiary amino group-containing diol (a1), but contain the tertiary amino group-containing diol (a1) and triethylenediamine. It can be seen that the storage elastic modulus is significantly reduced as compared with Reference Example 3 containing the mixture.
On the other hand, in the examples, since the improvement in room temperature curability is ensured by the tertiary amino group-containing diol (a1), the room temperature curability is good and an excessive amount of triethylenediamine is contained. Since it does not contain a tertiary amino group-containing diol (a1), it has extremely good high-temperature adhesiveness.

Claims (4)

Hydroxyl-terminated curing agent (A) and
A polyurethane-based adhesive forming composition containing an isocyanate group-terminated polyisocyanate (B).
The hydroxyl group terminal curing agent (A) is
A tertiary amino group-containing diol (a1) represented by the formula (I) and
Containing a polyol (a2) having an average functional group number of 3 or more,
The content of the tertiary amino group-containing diol (a1) is 0.04 mmol / g or more and 1.2 mmol / g or less in the polyurethane-based adhesive forming composition.
Polyurethane-based adhesive forming composition in which the content of the polyol (a2) is 0.2 mol or more and 9.0 mol or less with respect to 1 mol of the tertiary amino group-containing diol (a1):

During the ceremony
R ¹ independently represents a linear alkylene group having 1 to 4 carbon atoms.
R ² represents an alkyl group having 1 to 4 carbon atoms. Two R ¹ are identical, polyurethane adhesive-forming composition of claim 1. The polyurethane-based adhesive forming composition according to claim 1 or 2, wherein the content of triethylenediamine in the polyurethane-based adhesive forming composition is 0% by mass or more and 0.04% by mass or less. An adhesive containing the polyurethane-based adhesive forming composition according to any one of claims 1 to 3 and an inorganic filler (C).

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