WO2014196303A1

WO2014196303A1 - Adhesive composition

Info

Publication number: WO2014196303A1
Application number: PCT/JP2014/062260
Authority: WO
Inventors: 公範荒木; 美由貴森; 福井　宏
Original assignee: 横浜ゴム株式会社
Priority date: 2013-06-03
Filing date: 2014-05-07
Publication date: 2014-12-11
Also published as: JPWO2014196303A1

Abstract

The purpose of the present invention is to provide an adhesive composition having excellent storage stability and adhesion to a coated steel sheet. This adhesive composition includes: a mixture obtained by a method provided with a mixing step for mixing a liquid component (A) containing a polyol compound and a powder component (B) containing a filler to obtain a paste mixture, a dehydration step for removing at least a portion of moisture from the paste mixture after the mixing step, and a generation step for obtaining a mixture including a urethane prepolymer by mixing a polyisocyanate compound (C) and the dehydrated paste mixture and reacting component (C) and the polyol compound in the paste mixture; a bismuth-based compound and a tin-based compound as hardening catalysts; a C_nH_2n+1-COOH (n = 1-17) organic acid; and a polyisocyanate compound (D) having three or more isocyanate groups in one molecule thereof; the amount of the tin-based compound being 0.003-0.03 parts by mass per 100 parts by mass of the mixture.

Description

Adhesive composition

The present invention relates to an adhesive composition.

Conventionally, a one-component moisture-curable polyurethane composition containing a urethane prepolymer is known, and is used, for example, as an adhesive composition.
Examples of a method for producing such a one-component moisture-curable polyurethane composition include the method described in Patent Document 1. According to the method, “from the viewpoint of shortening the synthesis time, even if a metal catalyst is used for the production of the urethane prepolymer, it is possible to maintain a good viscosity, and further, excellent thixotropy and good appearance. Type polyurethane composition can be obtained ”(Patent Document 1, [0011]).

JP 2007-224150 A

Polyurethane composition can be used as an adhesive for automobiles and buildings. For example, a polyurethane composition can be used when attaching an automotive window glass directly to a body. In this case, a primer is often used for the glass and / or body from the viewpoint of adhesiveness, but in recent years, there is an increasing demand for primer-less from the viewpoint of environment, workability, cost, and the like.

Therefore, the present inventors added an adhesion-imparting agent and a curing catalyst to the composition obtained by the method described in Patent Document 1, and examined the performance as an adhesive. In some cases, it was difficult to make primer-less.
Moreover, even if the adhesiveness is relatively good, the viscosity may increase during storage.

The present invention has been made in view of the above points, and can be bonded to a coated steel sheet without using a primer (hereinafter, this is referred to as “excellent in adhesion”). An object of the present invention is to provide an adhesive composition having excellent storage stability.

As a result of intensive studies to achieve the above object, the present inventors have formulated a specific polyisocyanate compound, a curing catalyst, and a specific organic acid into a mixture (base material) containing a urethane prepolymer. The present invention was completed by finding that the adhesive composition to be used has excellent adhesion to a coated steel sheet and can suppress an increase in viscosity during storage.

That is, the present invention provides the following adhesive composition.
1. A liquid component (A) containing a polyol compound having two or more hydroxy groups in one molecule and a powder component (B) containing a filler are mixed, and the liquid component (A) and the powder component are mixed. A mixing step for obtaining a paste-like mixture with (B), a dehydration step for removing at least a part of residual moisture in the paste-like mixture after the mixing step, and two or more isocyanate groups in one molecule. A urethane prepolymer by mixing the polyisocyanate compound (C) having the paste-like mixture after the dehydration step and reacting the polyisocyanate compound (C) with the polyol compound in the paste-like mixture. A production step of obtaining a mixture comprising: a mixture obtained by a method comprising:
A bismuth compound and a tin compound as a curing catalyst;
C _n H _{2n + 1} —COOH (n = 1 to 17) as an organic acid,
A polyisocyanate compound (D) having three or more isocyanate groups in one molecule,
An adhesive composition wherein the amount of the tin compound is 0.003 to 0.03 parts by mass per 100 parts by mass of the mixture.
2. Per 100 parts by weight of the mixture,
The amount of the bismuth compound is 0.0005 to 0.005 parts by mass,
2. The adhesive composition according to 1 above, wherein the amount of the organic acid is 0.0005 to 0.01 part by mass.
3. 3. The adhesive composition according to 1 or 2 above, wherein the amount of the polyisocyanate compound (D) is 0.1 to 4.0 parts by mass per 100 parts by mass of the mixture.
4). 4. The adhesive according to any one of 1 to 3 above, wherein the polyisocyanate compound (D) is an aliphatic polyisocyanate and / or a modified product of an aliphatic polyisocyanate having two or more isocyanate groups in one molecule. Composition.
5. 5. The adhesive composition according to any one of 1 to 4 above, wherein the polyisocyanate compound (D) is a modified product of hexamethylene diisocyanate.
6). 6. The adhesive composition according to any one of 1 to 5 above, wherein the bismuth compound, the tin compound and the organic acid are a master batch in which these are mixed in advance.
7). 7. The adhesive composition according to any one of 1 to 6, wherein the mixture further contains the unreacted polyol compound and / or the unreacted polyisocyanate compound (C).
8). 8. The adhesive composition according to any one of 1 to 7, wherein a mass ratio of the bismuth compound and the tin compound (bismuth compound / tin compound) is 1/1 to 1/100.
9. 9. The adhesive composition according to any one of 1 to 8 above, wherein a metal catalyst is further used in the production step.

According to the present invention, it is possible to provide an adhesive composition having excellent adhesion to a coated steel sheet (especially high primer-less adhesion) and storage stability.

[Adhesive composition]
The adhesive composition of the present invention comprises:
A liquid component (A) containing a polyol compound having two or more hydroxy groups in one molecule and a powder component (B) containing a filler are mixed, and the liquid component (A) and the powder component are mixed. A mixing step for obtaining a paste-like mixture with (B), a dehydration step for removing at least a part of residual moisture in the paste-like mixture after the mixing step, and two or more isocyanate groups in one molecule. A urethane prepolymer by mixing the polyisocyanate compound (C) having the paste-like mixture after the dehydration step and reacting the polyisocyanate compound (C) with the polyol compound in the paste-like mixture. A production step of obtaining a mixture comprising: a mixture obtained by a method comprising:
A bismuth compound and a tin compound as a curing catalyst;
C _n H _{2n + 1} —COOH (n = 1 to 17) as an organic acid,
A polyisocyanate compound (D) having three or more isocyanate groups in one molecule,
An adhesive composition in which the amount of the tin-based compound is 0.003 to 0.03 parts by mass per 100 parts by mass of the mixture.

The adhesive composition of the present invention uses the above mixture (also referred to as “base material”) (contains), and thus has few production steps and is excellent in cost.
The adhesive composition of the present invention can have excellent adhesiveness by using a bismuth compound and a tin compound in combination as a curing catalyst.
Further, by containing a specific organic acid in a specific amount, it is possible to prevent the storage stability from being lowered by the combined use of the bismuth compound and the tin compound, and to contribute to the improvement of the coating plate adhesion.

[Mixture (base material)]
About the said mixture (base material), after explaining each component used for manufacture first, each process of the manufacture is demonstrated.

<Liquid component (A)>
The liquid component (A) is not particularly limited as long as it is a component containing a polyol compound having two or more hydroxy groups in one molecule, and may contain only the polyol compound. In addition, for example, it may contain a plasticizer or the like.
Here, the melting point of the polyol compound in the liquid component (A) is 80 ° C. or less from the viewpoint of becoming a liquid at the temperature at the time of mixing in the mixing step, which will be described later, and from the viewpoint of the viscosity at the time of urethane prepolymer generation. Preferably, it is 60 degrees C or less.

If the said polyol compound is a compound which has 2 or more of hydroxyl groups (OH group), the molecular weight, frame | skeleton, etc. will not be specifically limited. Hydroxy groups can be attached to organic groups. One preferred embodiment of the polyol compound is bifunctional to trifunctional.
As an organic group, the hydrocarbon group which may have hetero atoms, such as an oxygen atom, a nitrogen atom, and a sulfur atom, is mentioned, for example. Examples of the hydrocarbon group include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a combination thereof. The hydrocarbon group may be linear or branched and may have an unsaturated bond.
Specific examples of the polyol compound include polyhydric alcohols; polyether polyols; polyester polyols; polymer polyols having a carbon-carbon bond in the main chain skeleton such as acrylic polyols, polybutadiene polyols, and hydrogenated polybutadiene polyols. . A polyol compound may be used individually by 1 type, or may use 2 or more types together.

Among these, polyether polyols are preferred because the polyol compound is excellent in the hardness, cost, and viscosity (workability) of the composition containing the liquid component (A).

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol (PPG), polyoxypropylene triol, ethylene oxide / propylene oxide copolymer, polytetramethylene ether glycol (PTMEG), polytetraethylene glycol, and sorbitol-based polyol. It is done.
Among these, polypropylene glycol and / or polyoxypropylene triol is preferable because of the excellent balance between hardness and elongation at break and cost balance of the composition containing the liquid component (A).
A polyol having a weight average molecular weight of about 100 to 10,000 is preferred, and a polyol having a weight average molecular weight of 1,000 to 5,000 is more preferred. When the weight average molecular weight is within this range, the physical properties (for example, hardness, breaking strength, breaking elongation) and viscosity of the urethane prepolymer produced by the reaction with the polyisocyanate compound (C) described later are good.

Specific examples of the plasticizer contained in the liquid component (A) include, for example, diisononyl adipate (DINA); diisononyl phthalate (DINP); dioctyl adipate, isodecyl succinate; diethylene glycol dibenzoate, pentaerythritol ester Butyl oleate, methyl acetylricinoleate; tricresyl phosphate, trioctyl phosphate; propylene glycol adipate polyester, butylene glycol adipate polyester, and the like. These may be used alone or in combination of two or more. Also good.
Of these, it is preferable to use diisononyl adipate (DINA) and diisononyl phthalate (DINP) for reasons of excellent cost and compatibility.

In the case where the liquid component (A) contains the plasticizer, the content thereof is not particularly limited, but is 20 to 20 parts per 100 parts by mass in total of the polyol compound and the polyisocyanate compound (C). 80 parts by mass is preferable, and 30 to 70 parts by mass is more preferable.

<Powder component (B)>
The said powder component (B) will not be specifically limited if it is a component containing a filler, You may contain only this filler.

Examples of the filler include organic or inorganic fillers having various shapes. Specifically, for example, fumed silica, calcined silica, precipitated silica, ground silica, silica such as fused silica; diatomaceous earth; iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide; calcium carbonate, heavy Calcium carbonate, precipitated calcium carbonate (light calcium carbonate), colloidal calcium carbonate, magnesium carbonate, zinc carbonate; wax stone clay, kaolin clay, calcined clay; carbon black; treated with these fatty acids, treated with resin acid, urethane compound Product, fatty acid ester processed product, etc., and these may be used alone or in combination of two or more.
Among these, carbon black and heavy calcium carbonate are preferable because of easy adjustment of the viscosity and thixotropy of the composition. Specifically, when carbon black is used, physical properties (for example, hardness) , Elongation, etc.), and when heavy calcium carbonate is used, it is excellent in deep part curability.
In addition, since the carbon black is pellet carbon black, not only the workability is improved, but, as will be described later, in the mixing step with the liquid component (A), not only the carbon black but also the liquid component. It is preferable because the dehydration of (A) is further promoted.

The blending amount of the powder component (B) is not particularly limited, but is preferably 50 to 150 parts by weight, and 70 to 130 parts by weight with respect to 100 parts by weight as a total of the polyol compound and the polyisocyanate compound (C). Part is more preferred.

In addition to the filler, the powder component (B) includes, for example, an antioxidant, an antioxidant, a pigment (dye), a thixotropic agent, an ultraviolet absorber, a flame retardant, and a surfactant (including a leveling agent). , A dispersing agent, a dehydrating agent, an additive such as an adhesion-imparting agent other than (D), a tackifier, and an antistatic agent. Examples of various additives include conventionally known ones.

<Polyisocyanate compound (C)>
The polyisocyanate compound (C) is not particularly limited as long as it is a polyisocyanate compound having two or more isocyanate groups in one molecule. Isocyanate groups can be bonded to organic groups. The organic group is as defined above.
Examples of the polyisocyanate compound (C) include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates; and modified products thereof. Examples of the modified body include a carbodiimide modified body, an isocyanurate modified body, a biuret modified body, and an adduct modified body (the same applies hereinafter).
Specific examples of the polyisocyanate compound include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI), and tetramethylxylylene diisocyanate (TMXDI). , Aromatic polyisocyanates such as tolidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), triphenylmethane triisocyanate; aliphatics such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate Polyisocyanate; transcyclohexane-1,4-diisocyanate, isophorone diiso Aneto (IPDI), bis (isocyanatomethyl) cyclohexane (H ₆ XDI), alicyclic polyisocyanates such as dicyclohexylmethane diisocyanate (H ₁₂ MDI); these modified products (e.g., carbodiimide-modified, isocyanurate-modified adduct modified, Biuret modification), and these may be used alone or in combination of two or more.
Of these, the polyisocyanate compound (C) is preferably an aromatic polyisocyanate or a modified product thereof for reasons of physical properties after curing, and is tolylene diisocyanate (TDI) or diphenylmethane diisocyanate (MDI). Is more preferable.
In the aromatic polyisocyanate, the isocyanate group may be bonded to an aromatic hydrocarbon.

The blending amount of the polyisocyanate compound (C) is not particularly limited. For example, the equivalent ratio of the isocyanate group (NCO) of the polyisocyanate compound (C) to the hydroxy group (OH) of the polyol compound (NCO / OH) However, for example, an amount of 1.1 to 2.5 is preferable and can be 1.5 to 2.5.

<Mixing process>
The mixing step is a step of mixing the liquid component (A) and the powder component (B) to obtain a paste-like mixture of the liquid component (A) and the powder component (B).
Here, the method of mixing the liquid component (A) and the powder component (B) is not particularly limited as long as it is a conventionally known mixing method. Specifically, a roll, a kneader, a pressure kneader, Preferable examples include a Banbury mixer, a horizontal mixer (for example, a Laedige mixer), a vertical mixer (for example, a planetary mixer), a universal agitator, and the like.
Further, the temperature and time during mixing vary depending on the types of the liquid component (A) and the powder component (B), and are not particularly limited, but are preferably about 20 to 130 ° C. and 30 minutes to 2 hours. . In addition, since it is preferable that the liquid component (A) becomes a liquid at the temperature at the time of mixing in the mixing step, for example, when the temperature at the time of mixing is 100 ° C., a polyol compound having a melting point lower than that temperature is contained. Preferably, the liquid component (A) is used.

In the present invention, by including such a mixing step, a part of water in the liquid component (A) and the powder component (B) can be removed.
This is because when the liquid component (A) and the powder component (B) are mixed, the powder component (B) is easily crushed because there is no solvent such as toluene. Can be removed.

In the present invention, when pellet carbon black is used as the powder component (B), the mixing step mixes the liquid component (A) and pellet carbon black while pulverizing the pellet carbon black. Is preferred.
This is because the above-described pressure and heat generation are increased by the pulverization of the pellet carbon black, and the dehydration of the liquid component (A) and the pellet carbon black is further promoted.
Here, as a method of mixing while pulverizing, among the mixing methods exemplified above, a horizontal mixer that can be mixed with pressure applied to the pellet carbon black at the time of mixing (for example, a Laedige mixer) or the like The method of mixing using is suitably exemplified.

<Dehydration process>
The dehydration step is a step of removing at least part of the residual moisture in the paste-like mixture.
Here, as a method for removing the residual moisture, specifically, for example, a method of drying for about 30 minutes under a vacuum (1.2 kPa or less, preferably 0.6 to 1.2 kPa) at 30 to 60 ° C. Etc.

<Generation process>
The said production | generation process mixes the said polyisocyanate compound (C) and the said paste-form mixture after the said dehydration process, and makes the said polyisocyanate compound (C) and the said polyol compound in the said paste-form mixture react. And a step of obtaining a mixture (base material) containing a urethane prepolymer.
In a production | generation process, a polyisocyanate compound (C) and a polyol compound react, it becomes a urethane prepolymer, and the mixture containing a urethane prepolymer is obtained.
In addition to the urethane prepolymer, the mixture contains at least the powder (B) derived from the paste-like mixture.
Further, from the viewpoint that the mixture is excellent in storage stability and adhesiveness and excellent in heat aging resistance, the mixture further contains the unreacted polyol compound and / or the unreacted polyisocyanate compound (C). preferable.

Here, the method of mixing the polyisocyanate compound (C) and the paste-like mixture is preferably exemplified by the same method as the mixing method in the mixing step.
Moreover, since the temperature and atmosphere at the time of mixing differ depending on the types of the polyol compound and the polyisocyanate compound (C) in the paste-like mixture, they are not particularly limited. From the viewpoint of producing a urethane prepolymer, the polyisocyanate compound ( It is preferable to mix at a temperature equal to or higher than the melting point of C), and it is preferable to mix under an inert gas atmosphere such as nitrogen or argon or under reduced pressure.

In the present invention, by providing such a production step, the powder component (B) in the paste-like mixture is crushed by the thickening accompanying the prepolymerization of the urethane prepolymer, and the dispersibility is improved. Good thixotropy of the object.

In the present invention, in the production step, the paste mixture and the polyisocyanate compound (C) are preferably added and mixed in this order for the reason described below. That is, by adding in this order, for example, the polyisocyanate compound (C) is added as it is in the horizontal mixer used in the mixing step to obtain the paste-like mixture, and the generation step is performed. Therefore, workability is improved.
On the other hand, in the present invention, in the production step, the polyisocyanate compound (C) and the paste-like mixture are preferably added and mixed in this order for the following reason. That is, by adding in this order, the polyol compound is added to the polyisocyanate compound (C), so that a stable urethane prepolymer reaction occurs, and a urethane prepolymer having a uniform molecular weight is generated. Can do.

In this invention, it is preferable to use the metal catalyst which accelerates | stimulates the production | generation reaction of the said urethane prepolymer after mixing the said polyisocyanate compound (C) and the said paste-form mixture in the said production | generation process. By using a metal catalyst, the reaction between the polyol compound and the polyisocyanate compound (C) can be promoted to shorten the production time.
Thereby, the viscosity of the urethane prepolymer produced | generated can be maintained favorable. This is presumably because the viscosity can be maintained satisfactorily because the rapid formation reaction of the urethane prepolymer does not occur when the metal catalyst is added in the presence of the powder component (B).
Examples of such a metal catalyst include an organometallic catalyst. Examples of the organometallic catalyst include a tin catalyst and a bismuth catalyst. The tin-based catalyst is not particularly limited as long as it is a compound containing tin. The bismuth catalyst is not particularly limited as long as it is a compound containing bismuth.
Specific examples of the metal catalyst include tin-based catalysts such as dibutyltin dilaurate, dioctyltin laurate (DOTL), and dioctyltin dilaurate; bismuth-based catalysts (for example, inorganic bismuth (Neostan U- 600, U-660) and the like.
Of these, bismuth-based catalysts are preferable, and inorganic bismuth is more preferable.
In addition, the kind of metal catalyst which can be used in a production | generation process may be the same as that of the curing catalyst mentioned later, or may differ.

When the metal catalyst is used, the blending amount is preferably 0.001 to 0.03 parts by mass, and 0.002 to 0 with respect to 100 parts by mass in total of the polyol compound and the polyisocyanate compound (C). 0.02 parts by mass is more preferable.
When a tin-based catalyst is used as the metal catalyst in the production step, the amount of the metal catalyst is not included in the amount of the tin-based compound as the curing catalyst. Moreover, when using a bismuth-type catalyst as a metal catalyst in a production | generation process, the quantity of the said metal catalyst is not contained in the quantity of the bismuth-type compound as a curing catalyst.

The curing catalyst contained in the adhesive composition of the present invention will be described below. In the present invention, at least a bismuth compound and a tin compound are used as a curing catalyst.
The adhesive composition of the present invention can be cured by including a curing catalyst.
The bismuth compound used in the present invention is not particularly limited as long as it is a compound containing bismuth.
Examples of the bismuth compound include inorganic bismuth and organic bismuth. Although it does not restrict | limit especially as an inorganic bismuth, It is mentioned as one of the preferable aspects that it is an inorganic bismuth which does not contain an acid. Examples of organic bismuth include bismuth carboxylates such as bismuth octoate.
Among these, inorganic bismuth is preferable from the viewpoint of excellent storage stability and adhesiveness and excellent heat aging resistance.

The tin-based compound used in the present invention is not particularly limited as long as it is a compound containing tin.
Examples of the tin compound include carboxyltin carboxylates such as dioctyltin laurate (DOTL), dioctyltin dilaurate, dibutyltin dilaurate, dibutyltin maleate, dioctyltin maleate; and stannous stannate such as stannous octate. Carboxylic acid salts; chelates such as dibutyltin diacetylacetonate.
Among these, from the viewpoint of excellent storage stability and adhesiveness, and excellent heat aging resistance, alkyltin carboxylates are preferable, and DOTL is more preferable.
Bismuth compounds can be used alone or in combination of two or more. The same applies to tin-based compounds.

The organic acid contained in the adhesive composition of the present invention will be described below. In the present invention, at least C _n H _{2n + 1} —COOH (n = 1 to 17) is used as the organic acid.
In the present invention, the organic acid has a function of improving storage stability and coating plate adhesion. By including an organic acid, the adhesive composition of the present invention suppresses an increase in the viscosity of the composition due to the reaction of the composition during storage, and is excellent in storage stability. Moreover, it can suppress and maintain that the mechanical strength (for example, elongation at break) of the hardened | cured material exposed to high temperature falls.
In the above formula, C _n H _{2n + 1} may be linear or branched.
Examples of the organic acid used in the present invention include acetic acid, propanoic acid, butanoic acid, pentanoic acid, octanoic acid, decanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid (stearic acid).
Of these, stearic acid is preferable from the viewpoints of excellent storage stability and adhesiveness, heat aging resistance, and excellent handling.
The organic acids can be used alone or in combination of two or more.

The polyisocyanate compound (D) contained in the adhesive composition of the present invention is not particularly limited as long as it is a polyisocyanate compound having 3 or more isocyanate groups in one molecule. Isocyanate groups can be bonded to organic groups. The organic group is as defined above.
In the present invention, the polyisocyanate compound (D) can function as an adhesion-imparting agent.
As the polyisocyanate compound (D), aromatic polyisocyanate, aliphatic polyisocyanate, alicyclic polyisocyanate (excluding a modified product) having 3 or more isocyanate groups in one molecule; 2 in one molecule Examples include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanate modified products having at least one isocyanate group (for example, carbodiimide modification, isocyanurate modification, biuret modification, adduct modification). One of the preferred embodiments is that the aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate having two or more isocyanate groups in one molecule have two isocyanate groups in one molecule. . An aliphatic polyisocyanate having two or more isocyanate groups in one molecule may be hereinafter referred to as an aliphatic polyisocyanate (f1).
The number of isocyanate groups possessed by the polyisocyanate compound (D) is 3 or more per molecule, preferably 3 to 6, and more preferably 3 to 5.

Specific examples of the polyisocyanate compound (D) include, for example, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI). Aromatic polyisocyanates such as tetramethylxylylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), triphenylmethane triisocyanate; hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate ( TMHDI), aliphatic polyisocyanates such as lysine diisocyanate; transcyclohexane-1,4-diisocyanate Over DOO, isophorone diisocyanate (IPDI), bis (isocyanatomethyl) cyclohexane (H ₆ XDI), alicyclic polyisocyanates modified products such as dicyclohexylmethane diisocyanate (H ₁₂ MDI) (e.g., carbodiimide-modified, isocyanurate-modified adduct Modification, biuret modification), and these may be used alone or in combination of two or more.

The polyisocyanate compound (D) is superior in adhesion to the coated steel sheet and storage stability, and is excellent in heat aging resistance. Trifunctional or higher aliphatic polyisocyanate (excluding modified products) and / or aliphatic polyisocyanate. A modified product of isocyanate (f1) is preferred, and a modified product of hexamethylene diisocyanate is more preferred. In the aliphatic polyisocyanate, the isocyanate group may be bonded to an aliphatic hydrocarbon.
Examples of modified products include adducts (f2) of aliphatic polyisocyanates (f1) [reaction products of aliphatic polyisocyanates (f1) and triols], biurets (f3) of aliphatic polyisocyanates (f1). And at least one modified product selected from the group consisting of isocyanurate (f4) of aliphatic polyisocyanate (f1).

Examples of the aliphatic polyisocyanate (f1) include aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), and lysine diisocyanate.

Here, the triol is not particularly limited as long as it is a compound having three hydroxy groups in one molecule. Hydroxy groups can be attached to organic groups. The organic group is as defined above. Examples of the triol include 1,2,5-hexanetriol, 1,2,6-hexanetriol, 1,2,3-propanetriol, 1,2,3-benzenetriol, 1,2,4-benzenetriol. , Trimethylolethane, trimethylolpropane and the like.
As a modified product of the aliphatic polyisocyanate (f1), an adduct of HDI (for example, a reaction product of HDI and trimethylolpropane), a biuret of HDI, and It is preferably at least one selected from the group consisting of isocyanurates of HDI.
One preferred embodiment is that the polyisocyanate compound (C) used in the production of the mixture and the polyisocyanate compound (D) as the adhesion-imparting agent are different compounds.

In the adhesive composition of the present invention, the amount of the bismuth-based compound is 0.0005 to 0.005 parts by mass per 100 parts by mass of the mixture from the viewpoint of excellent adhesion and storage stability and excellent heat aging resistance. The amount is preferably 0.002 to 0.004 parts by mass.
When a bismuth-based catalyst is used as the metal catalyst in the production step, the amount of the bismuth-based compound as the curing catalyst does not include the amount of the bismuth-based catalyst as the metal catalyst.

Further, in this case, the total of the amount of the bismuth compound as the curing catalyst and the amount of the bismuth catalyst as the metal catalyst is 100 masses of the mixture from the viewpoint of being excellent in adhesiveness and storage stability and excellent in heat aging resistance The amount is preferably 0.0015 to 0.035 parts by mass per part.

In the present invention, the amount of the tin compound is 0.003 to 0.03 parts by mass per 100 parts by mass of the mixture. Further, from the viewpoint of excellent adhesion and storage stability and excellent heat aging resistance, the amount is preferably 0.008 to 0.02 parts by mass, and 0.01 to 0.018 parts by mass per 100 parts by mass of the mixture. It is more preferable that
When a tin-based catalyst is used as the metal catalyst in the production step, the amount of the tin-based compound as the curing catalyst does not include the amount of the tin-based catalyst as the metal catalyst.

In this case, the total of the amount of the tin-based compound as the curing catalyst and the amount of the tin-based catalyst as the metal catalyst is 100 masses of the mixture from the viewpoint of being excellent in adhesiveness and storage stability and excellent in heat aging resistance. The amount is preferably 0.004 to 0.06 parts by mass per part.

From the viewpoint that the mass ratio of the bismuth compound and the tin compound (bismuth compound / tin compound) as the curing catalyst is excellent in adhesion and storage stability and excellent in heat aging resistance, 1/1 to 1 / 100 is preferable, and 1/5 to 1/30 is more preferable.

The amount of the organic acid is preferably 0.0005 to 0.01 parts by weight per 100 parts by weight of the mixture, from the viewpoint of excellent adhesion and storage stability and excellent heat aging resistance. More preferably, it is 0.008 parts by mass.

The amount of the polyisocyanate compound (D) is preferably 0.1 to 5 parts by mass per 100 parts by mass of the mixture from the viewpoint of being excellent in adhesiveness and storage stability.
The amount of the polyisocyanate compound (D) is preferably 0.1 to 4.0 parts by mass per 100 parts by mass of the mixture from the viewpoint of excellent adhesion and storage stability and excellent heat aging resistance. More preferably, it is 5 to 2 parts by mass.
When the mixture contained in the adhesive composition of the present invention further contains an unreacted polyisocyanate compound (C), the amount of the polyisocyanate compound (D) includes the amount of the unreacted polyisocyanate compound (C). Absent.

The method for obtaining the adhesive composition of the present invention is not particularly limited. For example, the above mixture (base material), curing catalyst, organic acid, and polyisocyanate compound (D) are mixed, and the adhesive composition of the present invention is mixed. The method of obtaining is mentioned.
As the mixing method, a method similar to the mixing method in the mixing step is preferably exemplified.
The temperature and atmosphere during mixing are not particularly limited, but are preferably mixed at a temperature equal to or higher than the melting point of the polyisocyanate compound (D), and mixed under an inert gas atmosphere such as nitrogen or argon or under reduced pressure. It is preferable.

In addition, when a curing catalyst (bismuth compound, tin compound) and an organic acid are mixed in advance to form a master batch and mixed with other components using the master batch, the light weight and the uniform dispersibility are excellent.

As described above, since the adhesive composition of the present invention is excellent in adhesiveness and storage stability, it is suitable as an adhesive for automobiles, buildings, and the like.
Specifically, for example, it can be used for adhesion between glass and an automobile body (for example, a coated steel plate).
Examples of the coated steel sheet include a coated steel sheet coated with an acid-epoxy paint (acid-epoxy-coated steel sheet; hereinafter, a coated steel sheet coated with a certain paint is exemplified), an epoxy-based coated steel sheet, and acrylic. -Based coated steel sheet.
Since the adhesive composition of the present invention has good adhesion to a coated steel plate, it can be used for a coated steel plate without a primer.
The method for applying the adhesive composition of the present invention to a coated steel sheet is not particularly limited.
The adhesive composition of the present invention can be cured under conditions of 0 to 40 ° C. and 5 to 100 RH%.

Hereinafter, the present invention will be described in detail using examples. However, the present invention is not limited to this.

<Manufacture of mixture (base material)>
(Mixing process)
First, polyol compounds 1 and 2 and a plasticizer are added as a liquid component (A) to a Redige mixer (manufactured by Matsubo), and then carbon black and calcium carbonate are added as a powder component (B). A paste-like mixture was produced by stirring at 2 ° C. for 2 hours. In addition, the compounding quantity (unit: mass part) of each component is as showing in the following Table 1 (hereinafter the same).
(Dehydration process)
Next, the inside of the Leedige mixer containing the paste-like mixture was dried at 30 to 60 ° C. and 1.2 kPa or less for 30 minutes.
(Generation process)
Next, MDI is added to the planetary mixer as the polyisocyanate compound (C), and after adding the paste mixture after drying, the metal catalyst is added, and the mixture is stirred at 60 ° C. for 1 hour. And a polyol compound 1 and 2 in the pasty mixture to produce a urethane prepolymer to obtain a mixture (base material) containing the urethane prepolymer.

The components shown in Table 1 are as follows.
Polyol compound 1: bifunctional polypropylene glycol (EXCENOL 2020, manufactured by Asahi Glass Co., Ltd.)
Polyol compound 2: trifunctional polypropylene glycol (EXCENOL 5030, manufactured by Asahi Glass Co., Ltd.)
・ Plasticizer: Diisononyl phthalate (J-Plus)
Carbon black: A mixture of carbon black 1 (Niteron # 200, manufactured by Nisshin Carbon) and carbon black 2 (Niteron # 300, manufactured by Nisshin Carbon) (mass ratio = 75/25)
・ Calcium carbonate: Heavy calcium carbonate (Super S, manufactured by Maruo Calcium)

MDI: Diphenylmethane diisocyanate (Cosmonate PH, manufactured by Mitsui Chemicals)
・ Metal catalyst: Bismuth catalyst (Neostan U-600, manufactured by Nitto Kasei)

<Manufacture of adhesive composition>
Next, in the planetary mixer that obtained the above mixture (base material), the curing catalyst, acid compound, and adhesion-imparting agent [polyisocyanate compound (D)] shown in Table 2 below are blended in the same table (unit: And then stirred to obtain an adhesive composition.

Next, the following evaluation was performed using the adhesive composition produced as described above. The results are shown in Table 2 below.

<Storage stability> (viscosity after storage stability)
After manufacturing each adhesive composition, the SOD viscosity (Pa · s) after storage at 40 ° C. for 7 days was measured. The SOD viscosity was measured using a pressure viscometer (ASTM D 1092) according to JASO M338-89. From a practical viewpoint, if the SOD viscosity after storage is less than 100 Pa · s, it can be evaluated as having excellent storage stability.

<Coating steel sheet adhesion>
Each adhesive composition was coated with a round bead of φ10 mm on a coated steel sheet coated with an acid epoxy paint, and this was crimped to a thickness of 3 mm, and an atmosphere of 20 ° C. and 60% RH (± 5%). The test piece was left standing for 7 days and further immersed in warm water at 40 ° C. for 7 days and taken out from the water. Using the obtained test piece, a hand peeling test by knife cutting was performed.
As a result of the manual peel test, the case where the cohesive failure rate of the adhesive is 100% is evaluated as “◎”, the cohesive failure rate of the adhesive is 90% or more and less than 100%, and the interface peel rate is 10% or less. A case was evaluated as “◯”, and a case where the cohesive failure rate of the adhesive was less than 90% and an interfacial peeling rate exceeded 10% was evaluated as “x”.

<Heat aging resistance> (Adhesive breaking elongation)
A 2 mm-thick dumbbell-shaped No. 3 test piece was cut out from the cured sheet of each adhesive composition, and this test piece was left at 80 ° C. for 14 days for heat aging. Then, the test piece subjected to heat aging was subjected to a tensile test (tensile speed: 200 mm / min) according to JIS K6251-1993, and the elongation at break (unit:%) was measured. From a practical viewpoint, if the elongation at break after heat aging is 270% or more, it can be evaluated as having excellent heat aging resistance.

The curing catalysts shown in Table 2 are as follows.
Bi type: Inorganic bismuth (Neostan U-600H, manufactured by Nitto Kasei Co., Ltd., does not contain acid)
Sn system: Dioctyltin laurate (Neostan U-810, manufactured by Nitto Kasei Co., Ltd.)
・ Zr series: Zirconium acetylacetone chelate (Orgachix ZC-700, manufactured by Matsumoto Fine Chemical Co., Ltd.)

The acid compounds and adhesion-imparting agents shown in Table 2 are as follows.
- phosphate: manufactured by Kanto Chemical Co., Inc., formic acid: manufactured by Kanto Chemical Co., Inc. acetate: manufactured by Kanto Chemical Co., Inc. Stearic Acid: manufactured by Tokyo Kasei Kogyo Co., Ltd., C ₁₈ H ₃₇ -COOH: manufactured by Tokyo Kasei Kogyo Co., Ltd., HDI (2 functional): hexamethylene Diisocyanate, manufactured by Asahi Kasei Corporation ・ HDI modified (trifunctional): Isocyanurate of hexamethylene diisocyanate (trade name Duranate: manufactured by TPA-100)
TDI (bifunctional): tolylene diisocyanate, manufactured by Mitsui Chemicals Co., Ltd. TDI modified product (trifunctional): tolylene diisocyanate (trade name T-80, manufactured by Mitsui Chemicals) and trimethylolpropane (3: 1) reaction object

As is clear from the results shown in Table 2 above, in Examples 1 to 27, the viscosity after storage was less than 100 Pa · s, and the storage stability was excellent. In addition, the results of adhesiveness were both “」 ”or“ ◯ ”and were good. When the amount of the polyisocyanate compound (D) was 4.0 parts by mass or less per 100 parts by mass of the mixture, the elongation at break after heat aging was 270% or more, and the heat aging resistance was excellent.

On the other hand, Comparative Examples 1 to 14 were inferior in any of storage stability and adhesiveness.
Specifically, Comparative Examples 1 and 2 containing a bismuth compound or a tin compound as a curing catalyst and no specific organic acid were inferior in adhesion.
Comparative Examples 3 and 11 containing a bismuth compound and a tin compound as a curing catalyst and not containing a specific organic acid and an adhesion-imparting agent had lower storage stability than Comparative Examples 1 and 2.
Comparative Example 4 containing an adhesion-imparting agent but not containing an organic acid improved storage stability compared to Comparative Example 3, but the adhesion was still low.
Comparative Example 5 containing an organic acid but no adhesion-imparting agent improved storage stability compared to Comparative Example 3, but the adhesion was still low.
Comparative Examples 6-8 containing no specific organic acid and other acid compounds were inferior in adhesion. Comparative Example 7 was inferior in storage stability to Comparative Example 4.
Comparative Examples 9 and 10 which did not contain the polyisocyanate compound (D) and contained a bifunctional polyisocyanate compound instead were inferior in storage stability and adhesiveness.
Comparative Example 12 with a large amount of tin compound was inferior in storage stability.
Comparative Examples 13 to 14 containing no specific curing catalyst and specific organic acid were inferior in adhesion.

Claims

A liquid component (A) containing a polyol compound having two or more hydroxy groups in one molecule and a powder component (B) containing a filler are mixed, and the liquid component (A) and the powder component are mixed. A mixing step for obtaining a paste-like mixture with (B), a dehydration step for removing at least a part of residual moisture in the paste-like mixture after the mixing step, and two or more isocyanate groups in one molecule. A urethane prepolymer by mixing the polyisocyanate compound (C) having the paste-like mixture after the dehydration step and reacting the polyisocyanate compound (C) with the polyol compound in the paste-like mixture. A production step of obtaining a mixture comprising: a mixture obtained by a method comprising:
A bismuth compound and a tin compound as a curing catalyst;
C n H 2n + 1 —COOH (n = 1 to 17) as an organic acid,
A polyisocyanate compound (D) having three or more isocyanate groups in one molecule,
An adhesive composition wherein the amount of the tin compound is 0.003 to 0.03 parts by mass per 100 parts by mass of the mixture.
Per 100 parts by weight of the mixture,
The amount of the bismuth compound is 0.0005 to 0.005 parts by mass,
The adhesive composition according to claim 1, wherein the amount of the organic acid is 0.0005 to 0.01 parts by mass.
The adhesive composition according to claim 1 or 2, wherein the amount of the polyisocyanate compound (D) is 0.1 to 4.0 parts by mass per 100 parts by mass of the mixture.
The adhesion according to any one of claims 1 to 3, wherein the polyisocyanate compound (D) is an aliphatic polyisocyanate and / or a modified product of an aliphatic polyisocyanate having two or more isocyanate groups in one molecule. Agent composition.
The adhesive composition according to any one of claims 1 to 4, wherein the polyisocyanate compound (D) is a modified product of hexamethylene diisocyanate.
The adhesive composition according to any one of claims 1 to 5, wherein the bismuth compound, the tin compound and the organic acid are a master batch obtained by mixing them in advance.
The adhesive composition according to any one of claims 1 to 6, wherein the mixture further contains the unreacted polyol compound and / or the unreacted polyisocyanate compound (C).
The adhesive composition according to any one of claims 1 to 7, wherein a mass ratio of the bismuth compound and the tin compound (bismuth compound / tin compound) is 1/1 to 1/100.
The adhesive composition according to any one of claims 1 to 8, wherein a metal catalyst is further used in the production step.