JP5303899B2 - One-part moisture curable adhesive - Google Patents

Description

  The present invention relates to a one-part moisture curable composition suitable as a urethane-based adhesive.

Polyurethane resins are used in a wide range of applications such as adhesives, coating materials, sealing materials, flooring materials, elastic pavement materials, and waterproofing materials due to their excellent adhesion and flexibility.
In such applications, it contains an isocyanate group-terminated prepolymer obtained by reacting a raw material polyol and an isocyanate compound, and cures by reacting with moisture in the air or in the substrate to be bonded. Sexual compositions are known. In addition, it is known to use a polyether polyol or a polyester polyol as a raw material polyol.

When a polyether polyol which is a liquid at room temperature is used as the raw material polyol, a curable composition having good workability can be obtained because the prepolymer has a low viscosity. However, when used for adhesives applied to building materials, automobile parts, food packaging films, and waterproofing materials, the adhesiveness may be insufficient depending on the type of substrate to be adhered. For example, the adhesiveness is insufficient with respect to polyvinyl chloride sheets and aluminum sheets used as flooring or wallpaper.
On the other hand, when an adipic acid-based or phthalic acid-based polyester polyol is used as a raw material polyol, the adhesiveness to a polyvinyl chloride sheet or an aluminum sheet is excellent, but adipic acid-based polyester polyol has high crystallinity, It tends to become solid at room temperature, and there is a problem in workability. Further, in the one-component moisture curable type, moisture hardly penetrates into the inside of the resin, so that the moisture curable property tends to be insufficient. In addition, the phthalic polyester polyol has no crystallinity, but has a very high viscosity. When a prepolymer is used, the viscosity becomes even higher, which requires the use of a large amount of solvent and plasticizer. .

In view of this, a method has been proposed in which a polyether polyol having a low viscosity and a polyester polyol having excellent adhesiveness are used in combination. However, the polyether polyol and the polyester polyol are not compatible with each other, and there is a problem that the mixture thereof is easily separated into two layers.
In addition, since the reactivity between the polyether polyol and the polyester polyol is different from each other, it is necessary to go through complicated steps such as prepolymerization by reacting with the polyisocyanate compound in two stages when they are used in combination. .
A method of using a prepolymer using a polyester polyol and a prepolymer using a polyether polyol has also been proposed, but there is a problem of separation due to poor compatibility.
Patent Documents 1 and 2 propose a method in which a polyester-polyether block copolymer obtained by adding an alkylene oxide to a polyester polyol is used as an adhesive. However, since a polymer comprising a block copolymer chain of a polyester chain and a polyether chain is used, the polymer is easily aggregated and cannot be sufficiently reduced in viscosity.
Special table 2003-511532 gazette JP 2004-143314 A

Thus, although it is desired for the curable composition used for adhesives to be excellent in adhesiveness and low in viscosity, it is difficult to achieve both of them. Moreover, in order to obtain a large adhesive force, the breaking strength in the cured product is preferably large, and in order to obtain a good adhesion durability, it is preferable that the cured product has a good elongation.
The present invention was made to solve the above problems, a low viscosity, excellent in adhesiveness, strength at break and elongation in the cured product to provide a one-component moisture-curing adhesives is good For the purpose.

In order to achieve the above object, the present invention uses an isocyanate group-terminated prepolymer obtained by reacting a polyol (A) having a hydroxyl value of 10 to 300 mgKOH / g and a polyisocyanate compound (B) as a curing component. Polyester ether polyol obtained by copolymerizing a polycarboxylic acid anhydride (b) and an alkylene oxide (c) with an initiator (a), which is a liquid moisture curable adhesive A one-component moisture-curable adhesive comprising (A1) is provided.

According to the present invention, a one-component moisture-curable adhesive (hereinafter also referred to as “one-component moisture-curable composition”) having low viscosity, excellent adhesiveness, and good breaking strength and elongation in a cured product. Is obtained ) .

[Initiator (a)]
As the initiator (a) used when the polyester ether polyol (A1) is produced, it is preferable to use a compound having 2 to 8 active hydrogen atoms per molecule. Examples include polyhydric alcohols, polyamines, alkanolamines, and phenols.
Preferred examples include dihydric alcohols such as ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, and 1,4-butanediol; trivalents such as trimethylolpropane, trimethylolethane, and glycerin. Alcohols; tetrahydric alcohols such as pentaerythritol; hexahydric alcohols such as sorbitol and dipentaerythritol; and polyhydric alcohols such as octahydric alcohols such as sucrose; ethylenediamine, hexamethylenediamine and tolylenediamine Polyamines such as; alkanolamines such as monoethanolamine, propanolamine, and diethanolamine; and phenols such as bisphenol A.

Further, a polyether polyol having a hydroxyl value converted molecular weight per hydroxyl group of 150 to 1500 obtained by adding alkylene oxide to these polyhydric alcohols, polyamines, alkanolamines and phenols (hydroxyl value 37 to 374 mgKOH / g) Can also be used as initiator (a).
In addition, polyoxytetramethylene polyol, polyester polyol, polycarbonate polyol, and the like having a hydroxyl value-converted molecular weight per hydroxyl group of 150 to 1500 (hydroxyl value 37 to 374 mgKOH / g) can also be used as the initiator (a). Examples of the polyester polyol include those obtained by condensation reaction of polyhydric alcohols and polycarboxylic acids, and those obtained by ring-opening polymerization of lactone monomers using polyhydric alcohols as initiators.
The initiator (a) is preferably a polyhydric alcohol or a polyether polyol having a hydroxyl value-converted molecular weight of 150 to 1500 (hydroxyl value 37 to 374 mgKOH / g) per hydroxyl group to which an alkylene oxide is added using a polyhydric alcohol as an initiator. . This polyether polyol is particularly preferable when a double metal cyanide complex catalyst is used as the catalyst (x) when the polyester ether polyol (A1) is produced.
In the present invention, the hydroxyl value-converted molecular weight of a polyol refers to a value calculated using the following formula using a hydroxyl value measured by a method based on JIS K1557.
Hydroxyl value conversion molecular weight = (56100 / hydroxyl value) × number of polyol hydroxyl groups.

The number of hydroxyl groups in the polyester ether polyol (A1) is considered to be equal to the number of active hydrogen atoms per molecule of the initiator (a). In the present invention, it is more preferable to use a compound having 2 to 3 active hydrogen atoms per molecule as the initiator (a). The polyester ether polyol (A1) in the present invention has 2 to 3 hydroxyl groups. Is more preferable.
1-60 mass% is preferable with respect to the sum total of the preparation amount of all the raw materials used for the synthesis | combination of the polyester ether polyol (A1), and, as for the usage-amount of an initiator (a), 10-60 mass% is more preferable. When the use ratio of the initiator (a) is equal to or higher than the lower limit value of the above range, the characteristics of the initiator appear, and when it is equal to or lower than the upper limit value of the above range, the amount of the polycarboxylic acid anhydride in the polyester ether polyol is large. The mechanical properties and adhesiveness of a cured product obtained by moisture curing the obtained prepolymer are excellent.

[Polycarboxylic acid anhydride (b)]
Examples of the polycarboxylic acid anhydride (b) in the present invention include phthalic anhydride, maleic anhydride, succinic anhydride, and the like. In particular, an aromatic polycarboxylic acid anhydride is preferable because it has a very high cohesive force and polarity and thus greatly contributes to adhesion to various adherends. Phthalic anhydride is particularly preferred.
5-50 mass% is preferable with respect to the sum total of the preparation amount of all the raw materials used for the synthesis | combination of the polyester ether polyol (A1), and the usage-amount of the said polycarboxylic acid anhydride (b) is 10-40 mass%. Particularly preferred. By making the said usage-amount of polycarboxylic acid anhydride (b) 10 mass% or more, the mechanical strength and adhesiveness of the hardened | cured material obtained by moisture-curing the obtained prepolymer can be improved. Moreover, the viscosity of the obtained polyester ether polyol (A1) can be suppressed low by setting it as 50 mass% or less.

[Alkylene oxide (c)]
The alkylene oxide (c) polymerized with the initiator (a) together with the polycarboxylic acid anhydride (b) is preferably an alkylene oxide having 2 to 4 carbon atoms. Specific examples include propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, and ethylene oxide. Alkylene oxide may use only 1 type, or may use 2 or more types together. In the present invention, the use of ethylene oxide or propylene oxide is preferred, and the use of only propylene oxide is particularly preferred.

  The amount of alkylene oxide (c) used is preferably 50/50 to 95/5, more preferably 50/50 to 80/20 in terms of molar ratio (c / b) to polycarboxylic acid anhydride (b). By setting the molar ratio of the alkylene oxide (c) to be not less than the lower limit of the above range, the polyester ether polyol (A1) can be prevented from remaining unreacted polycarboxylic acid anhydride (b) in the polyester ether polyol (A1). ) Acid value can be lowered. Moreover, the adhesiveness and mechanical strength of the hardened | cured material obtained by moisture-curing the prepolymer obtained by making it below the upper limit of the said range are excellent.

[Catalyst (x)]
The polyester ether polyol (A1) in the present invention can be produced by subjecting the initiator (a) to addition polymerization of the polycarboxylic acid anhydride (b) and the alkylene oxide (c), but in terms of increasing the polymerization reaction rate. The catalyst (x) is preferably used for this polymerization reaction.
As the catalyst (x), a ring-opening addition polymerization catalyst is preferably used. Specific examples include alkali catalysts such as potassium hydroxide and cesium hydroxide; double metal cyanide complex catalysts; and phosphazene catalysts.
It is particularly preferable to use a double metal cyanide complex catalyst since a polyester ether polyol (A1) having a smaller Mw / Mn value can be obtained.
As the double metal cyanide complex, one in which an organic ligand is coordinated to a zinc hexacyanocobaltate complex is preferable. As the organic ligand, ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether and alcohols such as tert-butyl alcohol are preferable.
0.0001-0.1 mass% is preferable with respect to the polyester ether polyol (A1) which is a product, and the usage-amount of a catalyst (x) is more preferable 0.003-0.03 mass%. When the use ratio of the catalyst (x) is equal to or higher than the lower limit value of the above range, the polymerization occurs reliably, and when it is equal to or lower than the upper limit value of the above range, the residual catalyst is less adversely affected.

[Polyester ether polyol (A1)]
The polyester ether polyol (A1) is preferably obtained by copolymerizing the polycarboxylic acid anhydride (b) and the alkylene oxide (c) with the initiator (a) in the presence of the catalyst (x).
The polyester ether polyol (A1) can be prepared by the following method. First, the initiator (a), the polycarboxylic acid anhydride (b), and the catalyst (x) are put in a reaction vessel in advance, and the reaction is carried out while slowly adding the alkylene oxide (c) thereto. At that time, the polycarboxylic acid anhydride (b) has a faster ring-opening reaction than the alkylene oxide (c), and the polycarboxylic acid anhydride (b) does not undergo a continuous addition reaction. ) And alkylene oxide (c) can be obtained as a copolymer having a copolymer chain in which 1 mole is alternately added.
By adding alkylene oxide (c) excessively and adding only alkylene oxide (c) in a block to the terminal, the acid value of the resulting polyester ether polyol (A1) can be reduced. The acid value of the polyester ether polyol (A1) is preferably 2.0 mgKOH / g or less, more preferably 1.0 mgKOH / g or less, and may be zero. It is preferable that the acid value of the polyester ether polyol (A1) is not more than the above upper limit value because the reactivity with isocyanate is good and the prepolymer obtained is excellent in hydrolysis resistance of a cured product obtained by moisture curing. .
In the polyester ether polyol (A1), the portion where the polycarboxylic acid anhydride (b) and the alkylene oxide (c) are alternately added by 1 mol is constant in the ratio of both, so the molecular weight of the initiator (a) And the total amount of the alkylene oxide (c) at the terminal are designed.

In addition, even if a polymer obtained by reacting a phthalic polyester polyol and a polyisocyanate compound and a polymer obtained by reacting a polyether polyol and a polyisocyanate compound are mixed, a uniform mixture cannot be obtained.
Moreover, even if a polyester polyol and a polyether polyol are mixed first, and a polyisocyanate compound is reacted with the mixture to form a prepolymer, it is easily separated over time, and the compatibility is insufficient.

The hydroxyl value of the polyester ether polyol (A1) is preferably 11 to 112 mgKOH / g, particularly preferably 22 to 80 mgKOH / g. That is, the hydroxyl value converted molecular weight per hydroxyl group is preferably 500 to 5,000, particularly preferably 700 to 2,500. When the molecular weight in terms of hydroxyl value per hydroxyl group is 500 or more, the resulting curable composition has excellent adhesion to the adherend substrate. Moreover, the viscosity reduction of the curable composition obtained as the hydroxyl value conversion molecular weight per hydroxyl group is 5000 or less can be achieved.
Adjustment of the molecular weight in terms of hydroxyl value of the polyester ether polyol (A1) is easy by appropriately adjusting the number of moles of polycarboxylic acid anhydride (b) and alkylene oxide (c) to be polymerized with respect to the initiator (a). Can be done.

Further, the polyester ether polyol (A1) has a value (M ′) obtained by dividing the remaining molecular weight obtained by removing the molecular weight of the initiator (a) from the molecular weight in terms of hydroxyl value by the number of functional groups of the initiator (a), from 100 to 100. 3000 is preferable, and 200 to 1500 is particularly preferable.
Here, the above-mentioned “value (M ′) obtained by dividing the remaining molecular weight obtained by removing the molecular weight of the initiator from the hydroxyl value converted molecular weight by the number of functional groups of the initiator” is the polycarboxylic acid anhydride (b) and the alkylene oxide ( It means the average molecular weight per one copolymer chain formed by the copolymerization of c).
When the value (M ′) is 3000 or less, the viscosity of the obtained polyester ether polyol (A1) does not become too high, and when the value (M ′) is 100 or more, good adhesiveness is expressed. Can do. The adjustment of the value (M ′) is performed by appropriately adjusting the number of moles of the polycarboxylic acid anhydride (b) and the alkylene oxide (c) to be polymerized with respect to the initiator (a) as in the case of the molecular weight conversion molecular weight adjustment. It can be easily done by adjusting.
The viscosity of the prepolymer at 60 ° C. is not particularly limited, but is preferably 20,000 mPa · s or less, more preferably in the range of 1,000 to 15,000 mPa · s, from the viewpoint of applicability of the one-part moisture curable composition. preferable.
The value of the viscosity in this specification is a value (unit: mPa · s) obtained by measurement under the condition of 60 ° C. with an E-type viscometer (manufactured by Toki Sangyo Co., Ltd .: RE-80U model).

[Polyol (A)]
The polyol (A) is a high molecular weight polyol containing the polyester ether polyol (A1) having a hydroxyl value of 10 to 300 mgKOH / g, that is, a hydroxyl value converted molecular weight per hydroxyl group of 187 to 5610.
The hydroxyl value of the polyol (A) is preferably 11 to 112 mgKOH / g, and most preferably 22 to 80 mgKOH / g. That is, the hydroxyl value converted molecular weight per hydroxyl group is preferably 500 to 5000, and particularly preferably 700 to 2500.
The content of the polyester ether polyol (A1) in the total amount of the polyol (A) is preferably 30% by mass or more, and more preferably 50% by mass or more. It is most preferable that substantially 100% by mass is the polyether ether polyol (A1).

As the polyol (A2) other than the polyester ether polyol (A1) contained in the polyol (A), a compound having 2 to 8 active hydrogen atoms per molecule is used as an initiator, and an alkylene oxide is used. Polyoxypropylene polyol, polyoxyethylene polyol, polyoxyethylene propylene polyol obtained by ring-opening addition polymerization; polyester polyol obtained by condensation reaction of polyhydric alcohols and polycarboxylic acid; polyhydric alcohols Examples of the initiator include polyester polyols obtained by ring-opening polymerization of lactone monomers; polyoxytetramethylene polyols; polycarbonate polyols and the like. The other polyol (A2) is preferably a polyol having 2 to 8 hydroxyl groups, and more preferably 2 to 3 polyols. The hydroxyl value of the other polyol (A2) is preferably 10 to 300 mgKOH / g, more preferably 11 to 112 mgKOH / g, and particularly preferably 22 to 80 mgKOH / g. That is, the hydroxyl value converted molecular weight per hydroxyl group is preferably 187 to 5610, more preferably 500 to 5000, and particularly preferably 700 to 2500.
The content of the other polyol (A2) in the total amount of the polyol (A) is preferably 70% by mass or less, more preferably 50% by mass or less, and may be zero.

[Polyisocyanate compound (B)]
The polyisocyanate compound (B) (sometimes simply referred to as polyisocyanate (B)) that can be used in the present invention is not particularly limited, and examples thereof include diphenylmethane diisocyanate, polyphenylene polymethylene polyisocyanate, and 2,4-tolylene diisocyanate. And aromatic polyisocyanate compounds such as 2,6-tolylene diisocyanate; aralkyl polyisocyanate compounds such as xylylene diisocyanate and metatetramethylxylene diisocyanate; fats such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate Polyisocyanate compounds; alicyclic polyisocyanates such as isophorone diisocyanate and 4,4′-methylenebis (cyclohexyl isocyanate) Nate compounds; and urethane-modified products, burette-modified products, allophanate-modified products, carbodiimide-modified products, and isocyanurate-modified products obtained from the polyisocyanate compounds.
Since polyisocyanate compound (B) has excellent reactivity with polyol (A) and the viscosity of the resulting one-part moisture curable composition tends to be low, aromatic diisocyanates and their modified products are used. preferable. Of these, diphenylmethane diisocyanate, polyphenylene polymethylene polyisocyanate, 2,4-tolylene diisocyanate, and 2,6-tolylene diisocyanate, and modified products thereof are preferable.
A polyisocyanate compound (B) may be used individually by 1 type, and may use 2 or more types together.

[Prepolymer]
The isocyanate group-terminated prepolymer in the present invention is obtained by reacting the polyol (A) with the polyisocyanate compound (B).
In the isocyanate group-terminated prepolymer, the polyol (A) and the polyisocyanate compound (B) are reacted so that the molar ratio of the isocyanate group to the hydroxyl group (isocyanate group / hydroxyl group) is 1.3 to 10.0. It is obtained by. The molar ratio is more preferably 1.8 to 7.0. When the molar ratio is less than 1.3 or more, the viscosity of the produced prepolymer does not become too high, which is preferable in terms of workability and moisture curability. Moreover, by making it 10.0 or less, there is little remaining of the unreacted polyisocyanate compound (B), and the mechanical properties of the cured product of the finally obtained curable composition are improved.
The isocyanate group content in the isocyanate group-terminated prepolymer is preferably 0.5 to 20% by mass, more preferably 1 to 15% by mass, and particularly preferably 1 to 12% by mass. When the isocyanate group content is 0.5% by mass or more, the viscosity is not excessively high, which is preferable in terms of workability and moisture curability. When it is 20% by mass or less, there is little remaining unreacted polyisocyanate compound, and the mechanical properties of the cured product of the finally obtained curable composition are improved.

[One-part moisture curable composition]
The one-component moisture-curable composition of the present invention comprises an isocyanate group-terminated prepolymer obtained by reacting a polyol (A) and a polyisocyanate compound (B) as a curing component that is cured by reaction with moisture, The components are moisture-cured and are cured without the use of chain extenders or curing agents such as low molecular weight polyols and polyamines.
The one-component moisture curable composition of the present invention is produced under conditions where moisture does not enter, stored in a sealed container, removed from the container at the time of use, applied to a substrate, and exposed to the atmosphere. It can be cured by reacting moisture (humidity) with an isocyanate group in the curing component.
The production method of the one-component moisture curable composition of the present invention is not particularly limited, but preferably a stirrer such as a mixing mixer under reduced pressure or in a nitrogen atmosphere by adding the above essential components and various additives as necessary. It is preferable to sufficiently knead and uniformly disperse the composition to make a composition.

[Additive]
As an additive added as needed to the one-component moisture-curable composition of the present invention, for example, the following may be mentioned.
(Curing catalyst)
As a curing catalyst, a known catalyst that promotes urethanization reaction or urea reaction can be used. For example, tertiary amine compounds such as triethylamine, dibutyltin dilaurate, dioctyltin maleate, organic acid tin such as 2-ethylhexanoic acid tin, organic Lead acid etc. are mentioned.

(Plasticizer)
Examples of the plasticizer include dioctyl phthalate, dibutyl phthalate, diisononyl phthalate, dioctyl adipate, diisononyl adipate, isodecyl succinate, butyl oleate, tricresyl phosphate, propylene glycol adipate, and coconut oil fatty acid ester. .

(solvent)
A solvent may be contained in the one-component moisture-curable composition of the present invention. In particular, it is preferable to use a solvent for adhesives for food packaging films.
Solvents that can be used include aliphatic hydrocarbons such as isoparaffin and mineral spirits; acetates such as ethyl acetate and butyl acetate; ketones such as methyl ethyl ketone and methyl isobutyl ketone; aromatic hydrocarbons such as toluene and xylene; Amides such as dimethylformamide may be mentioned.
Since the one-component moisture-curable composition of the present invention can be reduced in viscosity by using the specific polyester ether polyol (A1), even if a solvent is used, a good viscosity can be obtained with a small amount of use. A weak solvent can also be used.

(Filler)
A filler can be mix | blended with the one-component moisture-curable composition of this invention as needed. In particular, in adhesive applications such as building material adhesives, coating materials, sealing materials, elastic pavement materials, waterproofing materials, etc., by blending fillers, it becomes difficult to sag even on the standing surface, the coating amount is uniform and stable, This is preferable because the adhesiveness is stabilized. Specific examples of the filler include calcium carbonate, titanium oxide, magnesium carbonate, magnesium oxide, magnesium hydroxide, iron oxide, zinc oxide, barium oxide, zinc carbonate, carbon black, silicas, and diatomaceous earth. 0-60 mass% is preferable in a curable composition (100 mass%), and, as for the usage-amount of a filler, 0-50 mass% is preferable. By setting it to 60% by mass or less, the adhesive application workability is good.

(Other auxiliaries)
Furthermore, a thixotropic agent, an antioxidant, an ultraviolet absorber, a pigment, an antifoaming agent, a flame retardant, and an adhesion imparting agent can be used as necessary.
Examples of the thixotropic agent include fine calcium carbonate, Aerosil (product of Nippon Aerosil Co., Ltd.), aliphatic amide, hydrogenated castor oil and the like.
Examples of the antioxidant include butylhydroxytoluene (BHT), butylhydroxyanisole (BHA), diphenylamine, phenylenediamine, and triphenyl phosphite.
Examples of ultraviolet absorbers include hindered phenols, benzotriazoles, and hindered amines.
The pigment includes an inorganic pigment and an organic pigment. Examples of the inorganic pigment include titanium dioxide, zinc oxide, ultramarine blue, bengara, lithopone, lead oxide, cadmium sulfide, cobalt oxide, and aluminum oxide. Examples of organic pigments include azo pigments and copper phthalocyanine pigments.
Examples of the antifoaming agent include polysiloxane compounds.
As the flame retardant, chloroalkyl phosphate, dimethyl methyl phosphate, ammonium polyphosphate, neopentyl bromide polyether, brominated polyether, bromine / phosphorus compound can be used.
As the adhesion-imparting agent, terpene resin, phenol resin, rosin resin, and xylene resin can be used.

Since the one-component moisture curable composition of the present invention has a low viscosity as shown in Examples described later, the workability is good. Moreover, the peel strength after adhesion is high and the adhesion is excellent, and the breaking strength and elongation in the cured product are good. In addition, it can be used for bonding to a wide range of materials.
As an adherend substrate, it can be used for a wide range of materials such as wood, metal materials such as aluminum, iron and copper; resin materials such as polyamide, polyethylene terephthalate, nylon and polypropylene; concrete, asphalt and stone. Of these substrates to be bonded, resins such as wood; aluminum; polyamide, and polyethylene terephthalate are preferable, and are particularly excellent in adhesion to aluminum.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples.
<Raw materials>
The polyols used as raw materials in the following examples are as follows. The molecular weight is a hydroxyl value converted molecular weight.
PPG-1000 (abbreviation): Polyoxypropylene diol having a hydroxyl value of 112 mgKOH / g and a molecular weight of 1000, produced using propylene glycol as an initiator and using a KOH catalyst.
PPG-2000 (abbreviation): Polyoxypropylene diol having a hydroxyl value of 56 mgKOH / g and a molecular weight of 2000, produced using propylene glycol as an initiator and using a KOH catalyst.
PBA (abbreviation): Poly (butylene diol) adipate diol having a hydroxyl value of 56 mg KOH / g and a molecular weight of 2000, manufactured by Nippon Polyurethane Industry Co., Ltd., trade name N-4010.
IP / MPD (abbreviation): Poly (3-methylpentanediol) isophthalate diol having a hydroxyl value of 56 mgKOH / g and a molecular weight of 2000, manufactured by Kuraray Co., Ltd., trade name P-2030.

[Production Example 1: Production of polyester ether diol (A1-1)]
1000 g of PPG-1000, which is a polyether polyol, was charged as an initiator (a) into a pressure-resistant reactor equipped with a stirrer and a nitrogen introduction tube. Next, 400 g (2.70 mol) of phthalic anhydride as the polycarboxylic acid anhydride (b) was put into the reaction vessel and stirred. Next, 0.2 g of zinc hexacyanocobaltate-tert-butyl alcohol complex catalyst was added as catalyst (x), and at 130 ° C. in a nitrogen atmosphere, 600 g (10.3 mol) of propylene oxide as alkylene oxide (c). Was allowed to react for 7 hours. Thereafter, after confirming that the decrease in the internal pressure of the reaction vessel stopped, the product was taken out from the reaction vessel, and polyester ether diol (A1--) in which phthalic anhydride and propylene oxide were polymerized at the end of the polyether polyol PPG-1000. 1) (hydroxyl value 56.3 mgKOH / g) was obtained. From the measurement result of ¹ H-NMR of this polyester ether diol, it was confirmed that this diol (A1-1) has polymer chains of phthalic anhydride and propylene oxide.
The polyester ether diol (A1-1) obtained in this example has a hydroxyl group-converted molecular weight per hydroxyl group of 996, “the remaining molecular weight obtained by removing the molecular weight of the initiator from the hydroxyl group-converted molecular weight is divided by the number of functional groups of the initiator. The value (M ′) ”was 496, and the acid value was 0.11.

[Production Example 2: Production of polyester ether diol (A1-2)]
In Production Example 1, the amount of phthalic anhydride used was changed to 600 g (4.05 mol), and the amount of propylene oxide used was changed to 400 g (6.90 mol). Otherwise, in the same manner as in Production Example 1, polyester ether diol (A1-2) (hydroxyl value 57.6 mgKOH / g) in which phthalic anhydride and propylene oxide were polymerized at the end of PPG-1000 was obtained. From the measurement result of ¹ H-NMR of this polyester ether diol, it was confirmed that this diol has a polymer chain of phthalic anhydride and propylene oxide.
The polyester ether diol (A1-2) obtained in this example had a hydroxyl equivalent molecular weight per hydroxyl group of 974, “the remaining molecular weight obtained by removing the molecular weight of the initiator from the hydroxyl equivalent molecular weight was divided by the number of functional groups of the initiator. The value (M ′) ”was 474, and the acid value was 0.14.

[Example 1: Production of one-component moisture-curable composition]
In a reaction vessel equipped with a stirrer and a nitrogen introduction tube, 757 g of the polyester ether diol (A1-1) obtained in Production Example 1 and 4,4′-diphenylmethane diisocyanate (Nippon Polyurethane Industry) as the polyisocyanate compound (B) 243 g of a trade name, Millionate MT, an isocyanate group content of 33.6% by mass, the same applies hereinafter), and reacted at 80 ° C. for 4 hours in a nitrogen atmosphere. The isocyanate group / hydroxyl group (molar ratio) was 2.56.
A part of the contents after the reaction was taken out and the content of isocyanate group (hereinafter sometimes abbreviated as NCO) was measured, and the reaction was stopped after confirming that the content was less than the theoretically calculated content. As a result, an isocyanate group-terminated prepolymer having an NCO content of 4.95% by mass and a viscosity at 60 ° C. of 3,300 (mPa · s) was obtained. This was used as a one-part moisture curable composition.

[Example 2: Production of one-part moisture curable composition]
An isocyanate group-terminated prepolymer was obtained in the same manner as in Example 1, except that the polyester ether diol (A1-1) was changed to the polyester ether diol (A1-2) obtained in Production Example 2 in Example 1. . Isocyanate group / hydroxyl group (molar ratio) was 2.50.
The obtained isocyanate group-terminated prepolymer had an NCO content of 4.87% by mass and a viscosity at 60 ° C. of 11,000 (mPa · s). This was used as a one-part moisture curable composition.

[Example 3: Production of one-part moisture-curable composition (containing additives)]
An additive was added to the isocyanate group-terminated prepolymer obtained in Example 1 to produce a one-part moisture curable composition.
That is, to 430 g of the isocyanate group-terminated prepolymer obtained in Example 1, 50 g of diisononyl phthalate as a plasticizer, 70 g of toluene as a solvent, heavy calcium carbonate as a filler (manufactured by Shiraishi Kogyo Co., Ltd .: NS-400 and the same). ) And 50 g of fine-grained synthetic calcium carbonate (manufactured by Shiraishi Kogyo Co., Ltd .: white gloss flower CCR) are used as a one-part moisture curable composition.

[Example 4: Production of one-component moisture-curable composition (containing additives)]
The same additive as in Example 3 was added to and kneaded with 430 g of the isocyanate group-terminated prepolymer obtained in Example 2 and used as a one-component moisture-curable composition.

[Example 5: Production of one-component moisture-curable composition (containing additives)]
In Example 1, the usage amount of the polyester ether diol (A1-1) was changed to 624 g, and the usage amount of 4,4′-diphenylmethane diisocyanate was changed to 376 g. Otherwise, the isocyanate group-terminated prepolymer was obtained in the same manner as in Example 1. Isocyanate group / hydroxyl group (molar ratio) was 4.83. The obtained isocyanate group-terminated prepolymer had an NCO content of 9.92% by mass and a viscosity at 60 ° C. of 1,800 (mPa · s).
What was kneaded by adding the same additive as Example 3 to 430 g of the obtained prepolymer was used as a one-component moisture-curable composition.

[Example 6: Production of one-component moisture-curable composition (containing additives)]
In Example 2, the usage amount of the polyester ether diol (A1-2) was changed to 622 g, and the usage amount of 4,4′-diphenylmethane diisocyanate was changed to 378 g. Otherwise, the isocyanate group-terminated prepolymer was obtained in the same manner as in Example 2. The isocyanate group / hydroxyl group (molar ratio) was 4.74. The obtained isocyanate group-terminated prepolymer had an NCO content of 9.90% by mass and a viscosity at 60 ° C. of 6,000 (mPa · s).
What knead | mixed by adding the same additive as Example 3 to 430 g of obtained prepolymers was used as a one-component moisture-curable composition.

[Comparative Example 1]
A one-part moisture-curable composition was prepared using a polyether polyol having no ester group instead of the polyester ether polyol (A1).
That is, in Example 1, instead of the polyester ether diol (A1-1) obtained in Production Example 1, an isocyanate group terminal was obtained in the same manner as in Example 1 except that polyoxypropylene diol (PPG-2000) was used. A prepolymer was obtained. The isocyanate group / hydroxyl group (molar ratio) was 2.57. The obtained isocyanate group-terminated prepolymer had an NCO content of 4.96% by mass and a viscosity at 60 ° C. of 850 (mPa · s). This was used as a one-part moisture curable composition.

[Comparative Example 2]
Instead of the polyester ether polyol (A1), a one-part moisture curable composition was prepared using an adipic acid-based polyester polyol.
That is, in Example 1, an isocyanate group was used in the same manner as in Example 1 except that poly (butylene diol) adipate diol (PBA) was used instead of the polyester ether diol (A1-1) obtained in Production Example 1. A terminal prepolymer was obtained. The isocyanate group / hydroxyl group (molar ratio) was 2.57. The obtained isocyanate group-terminated prepolymer had an NCO content of 4.90% by mass and a viscosity at 60 ° C. of 10,000 (mPa · s). This was used as a one-part moisture curable composition.

[Comparative Example 3]
Instead of the polyester ether polyol (A1), a one-part moisture curable composition was prepared using a phthalic polyester polyol.
That is, in Example 1, Example 1 except that poly (3-methylpentanediol) isophthalate diol (IP / MPD) was used instead of the polyester ether diol (A1-1) obtained in Production Example 1. In the same manner as above, an isocyanate group-terminated prepolymer was obtained. The isocyanate group / hydroxyl group (molar ratio) was 2.57. The obtained isocyanate group-terminated prepolymer had an NCO content of 4.98% by mass and a viscosity at 60 ° C. of 25,000 (mPa · s). This was used as a one-part moisture curable composition.

[Comparative Example 4]
Instead of the polyester ether polyol (A1), a one-component moisture curable composition was prepared using a mixture of a phthalic polyester polyol and a polyether polyol.
That is, 379 g of IP / MPD and 378 g of PPG-2000 were charged and mixed in a reaction vessel equipped with a stirrer and a nitrogen introduction tube, and 243 g of 4,4′-diphenylmethane diisocyanate was further charged. The reaction was carried out at 80 ° C. for 4 hours. The isocyanate group / hydroxyl group (molar ratio) was 2.57. A part of the content after the reaction was taken out and the NCO content was measured. After confirming that the content was less than the theoretically calculated content, the reaction was stopped and extracted, and the NCO content was 4.99% by mass, An isocyanate group-terminated prepolymer having a viscosity of 5,500 (mPa · s) at 60 ° C. was obtained. This was used as a one-part moisture curable composition.

<Evaluation>
[Physical properties of cured product (film)]
The one-component moisture-curable composition obtained in the above Examples and Comparative Examples was applied on a biaxially stretched polypropylene film (OPP film) with an applicator so as to have a film thickness of 500 μm, and conditions of 20 ° C. and relative humidity 60%. And cured for one week. The obtained film was cut into a predetermined shape with a dumbbell cutter and peeled off from the OPP film to prepare a test piece, and the following physical properties were measured.
Tensile modulus at 100% elongation (100% M, unit MPa), Tensile modulus at 300% elongation (300% M, unit: MPa), tensile strength at break (Ts, unit: MPa), and elongation at break (E , Unit:%) was measured. Physical property measurement conditions were based on JIS-K7311, using a tensile tester as a measuring instrument, using dumbbell No. 3 as a test piece, and a tensile speed of 200 mm / min.
The measurement results are shown in Table 1.

[Adhesion test]
In accordance with JIS K-6833, the adhesion test of the one-component moisture curable composition was performed by the following method.
(Test sample preparation)
A one-part moisture curable composition is applied with a spatula to a position of 25 mm × 25 mm at one end of a wood plywood (hereinafter abbreviated as veneer) 25 mm wide × 100 mm long × 4 mm thick to a thickness of 0.2 mm. did. On the coated portion, one end portion 25 mm × 25 mm of an aluminum plate (hereinafter abbreviated as Al) having a width of 25 mm × 100 mm length × 2 mm thickness is applied to the other end portion of the veneer and the other end portion of Al. The parts were placed so as to face each other and lightly pressed by hand, and further fixed with a clamping jig. This was cured for one week under conditions of 23 ° C. and 50% relative humidity to obtain a test sample.
(Peel test)
About the obtained test sample, using a tensile testing machine (product name: Tensilon VTM-III-200, manufactured by Toyo Baudwin Co., Ltd.), at a tensile speed of 50 mm / min, the shear peel strength (unit: N / m ^2). ) Was measured. The results are shown in Table 1.
Moreover, the peeling state after peeling was observed and evaluated visually. The results are shown in Table 1. In Table 1, “AF” indicates interfacial peeling. “AL (numerical value)” represents the peeled state as a percentage of area. For example, “AL80 peels off 80% of the total area of the bonded portion at the interface between Al and the curable composition, and 20 % Indicates peeling at the interface between the veneer and the curable composition, and the value of the area ratio in Table 1 is an average value when the same peeling test is performed on three test samples.

From the results of Examples 1 and 2 and Comparative Examples 1 to 4, the one-component moisture-curable composition of Examples 1 and 2 comprising the prepolymer according to the present invention is low in viscosity and easy to use, and the composition is cured. The film thus obtained has excellent elongation and good breaking strength. In addition, it has high shear peel strength and excellent adhesiveness.
On the other hand, Comparative Example 1 composed of a prepolymer prepared using a polyether polyol has a low viscosity and good film elongation, but is inferior in film breaking strength and adhesiveness.
Comparative Examples 2 and 3 made of a prepolymer prepared using a polyester polyol have good adhesiveness but are inferior in elongation and breaking strength of the cured product (film). If the elongation of the film is not good, peeling tends to occur when used for bonding adherends having different heat shrinkage rates.
The composition of Comparative Example 4 consisting of a prepolymer prepared using a mixture of polyether polyol and polyester polyol separated the liquid when allowed to stand, and was formed on a biaxially stretched polypropylene film (OPP film) to a film thickness of 500 μm with an applicator. Even if it was applied, a uniform film could not be obtained. For this reason, in the comparative example 4, evaluation of the film physical property and adhesiveness was not performed.

  When additives such as calcium carbonate are blended as in Examples 3 to 6, properties such as dripping prevention can be imparted, and the cost of the product can be reduced. In Examples 3 to 6, it was confirmed that even when an additive was added, the shear strength was high and the adhesiveness was good, and there was no practical problem as an adhesive. In addition, when calcium carbonate was added, it became a non-Newtonian fluid and the viscosity could not be measured, so the viscosity was not measured.

The one-part moisture curable composition of the present invention is suitable for bonding applications, and specifically, requires good adhesion to a substrate such as an adhesive, a coating material, a sealing material, an elastic pavement material, or a waterproof material. It is preferable that it can be used for applications.
Since it has excellent adhesion to wood, metal (particularly aluminum) and resin, it is suitable as an adhesive for building materials; an adhesive for automobile parts; and an adhesive for laminates such as food packaging films.

Claims (4)

A one-component moisture curable adhesive comprising an isocyanate group-terminated prepolymer obtained by reacting a polyol (A) having a hydroxyl value of 10 to 300 mgKOH / g and a polyisocyanate compound (B) as a curing component,
The polyol (A) includes a polyester ether polyol (A1) obtained by copolymerizing a polycarboxylic acid anhydride (b) and an alkylene oxide (c) with respect to an initiator (a). One-part moisture curable adhesive . The reaction for copolymerizing the polycarboxylic acid anhydride (b) and the alkylene oxide (c) with the initiator (a) is performed in the presence of a double metal cyanide complex catalyst (x). One-component moisture-curable adhesive described in 1. The one-component moisture-curable adhesive according to claim 1 or 2, wherein the content of the polycarboxylic acid anhydride (b) in the polyester ether polyol (A1) is 10 to 50% by mass. The one-component moisture curable adhesive according to any one of claims 1 to 3, wherein the polycarboxylic acid anhydride (b) is phthalic anhydride.