JP3447555B2 - One-part moisture-curable urethane liquid adhesive composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-liquid solventless moisture-curing urethane liquid adhesive.

[0002]

2. Description of the Related Art A one-pack moisture-curable urethane adhesive is mainly composed of a urethane prepolymer having an isocyanate group at its end (hereinafter referred to as "prepolymer"), and the isocyanate group has a moisture content in the air or an object to be covered. The adhesive layer is formed by reacting with moisture in the adherend and curing and crosslinking to adhere various adherends.

Conventionally, a one-part moisture-curable urethane adhesive has been prepared by reacting a polyol with an excess of polyisocyanate in the presence or absence of an organic solvent to give a urethane prepolymer having an isocyanate group at the end. A polymer was synthesized and, if necessary, a filler, an organic solvent, a thixotropic agent, a curing catalyst, and the like were added to form an adhesive.

Among the one-component moisture-curable urethane adhesives, if the solvent type is used, a large amount of a volatile organic solvent is used as a solvent for dilution, so that the molecular weight of the urethane prepolymer may be extremely increased. Therefore, the initial adhesiveness, which immediately develops when the organic solvent evaporates, can give an excellent initial tack state (hereinafter referred to as “initial tack”) due to the characteristics of the polymer. Further, as the characteristic of this solvent type, since the organic solvent assists the wettability necessary for adhesion, which is a problem of the polymer, by both the wetting effect and the diluting effect, the adhesiveness is also good.

The organic solvent used in this one-component solvent-type moisture-curing urethane adhesive has a boiling point of 100 ° C. or less, as typified by ethyl acetate, methyl ethyl ketone, and methylene chloride, in order to obtain early tack development strength. The so-called low boiling point solvent, or the so-called medium boiling point solvent having a boiling point of 100 ° C. to 150 ° C. such as toluene, xylene, and methyl isobutyl ketone is generally used. Since the high boiling point solvent, the plasticizer, etc. are delayed in drying, they are used only in an auxiliary manner as needed.

[0006] These solvents have a serious problem in that they have an odor due to the volatilization of the solvent at the time of application and have an effect on the health of workers, and since they are flammable dangerous substances, attention to prevent fire is important. In addition, it is subject to laws and regulations such as the Fire Service Law, and the storage quantity is also limited.

As described above, the one-component solvent-type moisture-curable urethane-based adhesive has the speed and strength of initial tack development and good adhesiveness, but in today's society, it has dangerous and harmful properties based on organic solvents. It is well known that this is a serious drawback of this adhesive.

[0008] A means for solving the difficulty is to eliminate the solvent, but it is not realized by simply reducing the organic solvent to zero. That is, an adhesive is required to develop a high degree of initial tack as early as possible, but normally the urethane prepolymer used for the one-component moisture-curable urethane adhesive needs to be liquid, and within that range. When using a prepolymer having a molecular weight as large as possible, firstly the coating operation is difficult, and secondly, the high molecular weight polymer has poor wettability,
The technical difficulty arises that the adhesiveness comparable to the solvent type cannot be obtained at all.

[0009] Actually, the one-component solventless moisture-curing urethane adhesives that have hitherto been commercially available have no choice but to use a low-molecular weight prepolymer, so that they have a poor initial tack and a slow onset. Is pointed out. In addition, in order to further improve the coating workability, it is necessary to dilute it with some organic solvent. In addition, in terms of adhesiveness, the wettability is poorer than that of the solvent type, and therefore both adhesiveness and adhesive strength are inferior to those of difficult-to-adhesive materials such as plastics.

[0010]

DISCLOSURE OF THE INVENTION The present invention improves the coating workability, which is a drawback of the conventional one-component solventless moisture-curing urethane adhesives, and imparts excellent adhesiveness to the rapid curing property. It is to enable early development of good initial tack based on the above.

[0011]

DISCLOSURE OF THE INVENTION The present inventors are looking for a diluent having excellent dilutability as an alternative to the conventional low-boiling to medium-boiling organic solvent for a moisture-curable adhesive using a urethane prepolymer. It was As a result, N-methyl-2-pyrrolidone was found, but it was found from a literature survey that this diluent was used together with dimethylformamide as a solvent during urethane polymerization. However, it has been discovered that this diluent not only provides a simple dilution effect, but also provides various unexpected properties.

That is, the diluent is
Not only leading to low viscosity, but also providing excellent adhesiveness to difficult-to-adhere materials such as metals, rubbers, plastics, and even the effect of accelerating the curing speed. The discovery was the origin of the present invention.

The low viscosity as referred to in the present invention is a range of viscosities which become liquid at room temperature. Specifically, for example, the viscosity at a rotation speed of 20 r / min of a B type rotational viscometer (23 ° C.).
Indicates 100 Pa · s or less.

Further, when a specific urethane curing catalyst, bis (morpholinoethyl) ether, bis (2,6-dimethylmorpholinoethyl) ether, or bis (3,5-dimethylmorpholinoethyl) ether is used in combination, the above-mentioned characteristics are obtained. It was discovered that the effect of accelerating the curing rate is remarkable due to the interaction while maintaining the above. Therefore, the curing speed is faster than when this specific urethane curing catalyst is used alone.

After that, further research was carried out with the aim of reducing the viscosity of the prepolymer and improving the balance of the adhesive function and the initial tack, and as a result, a specific polyether was used to lower the viscosity of the prepolymer and balance the adhesive function. For the technical means of using a polyol and a specific polyester polyol in combination, the rapid curing and the early development of the initial tack that develops as a result, a technical means of using a specific amine compound as a curing catalyst was discovered, and the purpose of the present invention was further improved. The present invention has been completed by reaching such improvement.

The technical means of the present invention will be specifically described below.
The present invention is an isocyanate-terminated urethane prepolymer.
On the other hand, a low content of N-methyl-2-pyrrolidone
Can be applied at room temperature, characterized by high viscosity and high adhesiveness
One-component moisture-curing urethane liquid adhesive composition
It can be done.

That is, the invention of claim 1 has a molecular weight of 2000.
1 of the above isocyanate-terminated urethane prepolymers
0.1 to 30 parts by mass of N-methyl-based on 100 parts by mass.
Made with 2-pyrrolidone to have low viscosity and high adhesiveness
1 liquid moisture curing type urethane liquid type
It is an adhesive composition .

In the invention of claim 2 , the isocyanate-terminated urethane prepolymer is a polyoxypropylene polyol, and a polyester polyol obtained by the reaction of a polyhydric alcohol and a polycarboxylic acid and an isocyanate obtained by polyisocyanate. The one-part moisture-curable urethane liquid type adhesive composition which can be applied at room temperature according to the means of claim 1 , characterized in that it has a low viscosity which is a urethane prepolymer at the end and has improved balance of adhesive performance.

In the invention of claim 3, claim 1 or claim 1
For the one-part moisture-curable urethane-based liquid adhesive composition in the second means , bis (morpholinoethyl) ether, bis (2,6-dimethylmorpholinoethyl) ether, bis (3,5-dimethylmorpholinoethyl) A one-component moisture-curable urethane-based liquid-type adhesive composition that can be applied at room temperature, characterized by improving the rapid curing property by blending one or more amine compounds selected from ethers.

The starting polyol for the urethane prepolymer of the present invention can be classified into polyether polyol and polyester polyol.

As the polyether polyol, polyoxyalkylene diol (specifically, polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, etc. and copolymers thereof), polyoxyalkylene triol (specifically, Polyoxyalkylene polyols such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. and glycerin, trimethylolpropane, etc.), and other bisphenols, sugars, amines, etc. as starting materials to produce ethylene oxide or propylene oxide. Examples thereof include added diol, polyether polyol, and polyoxytetramethyl glycol obtained by ring-opening polymerization of tetrahydrofuran.

Of these, polyoxyalkylene diols and polyoxyalkylene triols are preferably used because of low viscosity and easy liquefaction.

As the polyester polyol, conventionally known ones can be widely used as long as they are compounds having an ester bond as a repeating unit and having a hydroxyl group at the terminal. Specifically, a condensation polyester polyol obtained by dehydration condensation of a polyvalent carboxylic acid (mainly adipic acid or phthalic acid) and a polyhydric alcohol (specifically glycol, triol, etc.); ring-opening polymerization of ε-caprolactone A lactone-based polyester polyol obtained by: a polycarbonate diol obtained by phosgenation of a polyol or a transesterification reaction with diphenylene carbonate; a polyester polyol obtained by a polyaddition reaction of a polycarboxylic acid anhydride and diepoxide; The urethane-modified polyester polyol as introduced can be mentioned.

Of these, polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol and adipic acid and sebacic acid are used because of their excellent adhesion. It is preferable to use a condensed polyester polyol obtained by a condensation reaction with a polycarboxylic acid such as isophthalic acid or trimellitic acid.

Examples of polyols other than the above are dihydric alcohols such as ethylene glycol, propylene glycol and 1,4-butanediol, polyhydric alcohols such as glycerin, trimethylolpropane and neopentyl glycol, and hydroxyl group-terminated polybutadiene (1,2). -Adducts, 1,
4-adduct), a so-called rosin-modified polyol having a rosin skeleton in the molecule, an amine polyol having an amine structure in the molecule, a so-called silicone in which carbinol is introduced into both terminals of a polysiloxane called carbinol-modified silicone oil. -Based diols, so-called acrylic polyols having an acrylic acid ester (including methacrylic acid ester) as a skeleton, so-called fluorine having a hydroxyl group at the end of a fluororesin (for example, a copolymer resin of ethylene difluoride and acrylic) Resin type polyol etc. can be mentioned.

As the polyisocyanate used in the present invention, an aliphatic, aromatic or alicyclic polyisocyanate compound having a plurality of isocyanate groups in the molecule, preferably 2 to 3 on average, is used.

Specifically, for example, 2,4-toluene diisocyanate (hereinafter referred to as "2,4-TDI"),
2,6-Toluene diisocyanate (hereinafter referred to as "2,6-
TDI ”. ), 2,4-TDI and 2,6-TDI
An isomer mixture of 4,4'-diphenylmethane diisocyanate (hereinafter referred to as "4,4'-MDI"),
2,4'-diphenylmethane diisocyanate (hereinafter,
It is called "2,4'-MDI". ), An isomer mixture of 4,4′-MDI and 2,4′-MDI (trade name: Luplanate MI, manufactured by BSF Japan Ltd.), carbodiimide-modified MDI, polymethylene polyphenyl polyisocyanate (hereinafter, referred to as “polymeric MDI”). , "And hexamethylene diisocyanate (hereinafter referred to as" H
MDI ”. ), Xylene diisocyanate (hereinafter referred to as “XDI”), meta-xylene diisocyanate, 1,5-naphthalene diisocyanate, hydrogenated M
Isocyanate compounds such as DI, hydrogenated TDI, hydrogenated XDI, and isophorone diisocyanate; Sumidule N
Burette polyisocyanate compounds such as (Sumitomo Bayer Urethane Co.); Desmodur IL, HL (manufactured by Bayer AG), Coronate EH (manufactured by Nippon Polyurethane Industry Co., Ltd.), etc. L (Sumitomo Bayer Urethane Co., Ltd.), Coronate HL (Nippon Polyurethane Industry Co., Ltd.)
And other adduct polyisocyanate compounds.

Among these, 4,4'-MDI and crude products thereof, a mixture of 4,4'-MDI and 2,4'-MDI and the use of these crude products have a high initial tack strength, It is preferable in terms of adhesiveness, adhesive strength, and good coating work.

The isocyanate-terminated urethane prepolymer is usually selected from polyether polyols, polyester polyols, and other polyols.
It is synthesized by allowing excess polyisocyanate to act on a mixed polyol obtained by one kind or a combination of two or more kinds.

The term "excess polyisocyanate" as used herein means that the chemical equivalents of the isocyanate groups are more than the chemical equivalents of the hydroxyl groups of all the polyol components, and the relationship of the chemical equivalents may be expressed by the NCO / OH ratio. it can. That is, theoretically, if the NCO / OH ratio exceeds 1, it can be an isocyanate terminal, but since the present invention is characterized in that it is liquid, the NCO / OH ratio is usually preferably 1.5 or more. The upper limit of the NCO / OH ratio is not particularly limited, but an NCO / OH ratio of 10.0 or less is preferable in view of adverse effects such as curing delay and increase of foaming during moisture curing. Especially to lead to liquid and low viscosity prepolymer,
It is particularly preferable to adjust the NCO / OH ratio to about 1.5 to 8.0 while considering the type of polyol, the number of functional groups, the molecular weight and the like.

Although the polymerization temperature and the polymerization time are not particularly limited, it is usually preferable that the polyol and the polyisocyanate are mixed under a nitrogen gas stream and then reacted at 50 to 100 ° C. for 3 to 8 hours.

The N-methyl-2-pyrrolidone used in the present invention may be a commercially available product as it is, but in order to obtain long-term storage stability, water was removed with a commercially available dehydrating agent such as molecular sieve or silica gel. Is preferred.

The amount of N-methyl-2-pyrrolidone used in the present invention is 0.
1 to 30 parts by mass is preferable. If the amount is less than 0.1 parts by mass, the viscosity of the adhesive will be low, and the adhesiveness to the poorly adhesive material will be imparted, and the effect of accelerating the curing rate will be poor, and if it exceeds 30 parts by mass, conversely. The effect of the initial tack is weakened, and it becomes difficult to secure the adhesive strength for the next work, and the effect originally possessed by N-methyl-2-pyrrolidone is not expressed. The most preferable range of the compounding amount of N-methyl-2-pyrrolidone that most significantly exhibits the above effects is 0.5 to 30 parts by mass.

When blended in the adhesive of the present invention, it may be blended at any time during the urethane prepolymer synthesizing step and the adhesive manufacturing step, but N-methyl-2-pyrrolidone is easy to absorb water. Therefore, it is preferable during the manufacturing process of the adhesive that is less affected by moisture. Most preferably, it is compounded in the final manufacturing process of the adhesive.

Among the polyoxypropylene polyols in the present invention, polyoxypropylene diol is synthesized by addition-polymerizing propylene oxide with propylene glycol, neopentyl glycol or the like as an initiator.
Polyoxypropylene triol is synthesized by addition-polymerizing propylene oxide with glycerin or trimethylolpropane as an initiator. Those having a molecular weight of 400 to 20,000 are usually used.

The polyester polyols obtained by the reaction of the polyhydric alcohol and the polycarboxylic acid in the present invention include, for example, polyester polyols obtained by the condensation reaction of propylene glycol and adipic acid (trade name). : ADEKA NEWACE F7-67, molecule
Amount 2000 , bifunctional, manufactured by Asahi Denka Kogyo Co., Ltd. or polyester polyol obtained by condensation reaction of diethylene glycol and adipic acid (trade name: ADEKA New Ace F)
15-22, molecular weight 2000, bifunctional, manufactured by Asahi Denka Kogyo Co., Ltd.).

The bis (morpholinoethyl) ether, bis (2,6-dimethylmorpholinoethyl) ether and bis (3,5-dimethylmorpholinoethyl) ether of the present invention are represented by the following general formula.

[0038]

[Chemical 1]

In the formula, R ² is a C ₁ -C ₃ alkyl group, n
Represents an integer of 0 to 4, and this compound represented by this formula is a urethane curing catalyst.

The bis (morpholinoethyl) ethers are excellent in storage stability and are called a so-called foam type amine-based catalyst which promotes the reaction between isocyanate group and water suitable for the production of urethane foam. It is a general urethane polymerization catalyst that is used in many applications such as caulking materials such as urethane sealants because it is excellent not only in production but also in storage stability.

The mixing ratio of this urethane curing catalyst is 0.05 to 10 with respect to 100 parts by mass of the urethane prepolymer.
Parts by mass. If the amount is less than 0.05 parts by mass, the curing acceleration effect due to the interaction with N-methyl-2-pyrrolidone is poor, and if the amount is more than 10 parts by mass, the storage stability such as an increase in the viscosity of the adhesive over time becomes extremely poor.

This curing catalyst may be used in combination with another amine-based urethane catalyst or an organometallic urethane catalyst such as dibutyltin dilaurate, depending on the purpose.

The manufacturing process of the adhesive of the present invention will be described below. In the manufacturing process, under a dry nitrogen gas flow in a closed container in which moisture is blocked, with respect to the prepolymer, an inorganic filler, a thixotropic agent, a plasticizer, a diluent, a tackifying resin, an adhesiveness imparting agent, a curing catalyst, It is manufactured by blending various modifiers such as a moisture binder, a stabilizer, a colorant, and an organic solvent, and mixing and processing.

Since this adhesive becomes unstable due to the influence of moisture during the manufacturing process and storage, it is necessary to remove moisture as much as possible from raw materials having moisture in the blended raw materials in order to stabilize the quality of the adhesive over a long period of time. It is preferable in terms of obtaining.

Examples of the inorganic filler used in the present invention include inorganic fillers that can be industrially used as fillers such as calcium carbonate, clay, talc, magnesium oxide, diatomaceous earth, and glass balloon, and each of them may be used alone or as a mixture. Can be used.

Examples of the thixotropic agent include ultrafine silica powder and hydrogenated castor oil.

Examples of the plasticizer include dioctyl phthalate, dibutyl phthalate, dilauryl phthalate,
Butylbenzyl phthalate, dioctyl adipate, diisodecyl adipate, trioctyl phosphate,
Mineral spirits and the like can be mentioned, and each can be used alone or as a mixture.

As the diluent, a petroleum hydrocarbon diluent,
Examples thereof include esters such as 3-methyl-3-methoxybutyl acetate and dimethyl glutarate.

As the tackifying resin, conventionally known resins can be used. Specifically, for example, in natural resin-based tackifying resins, rosin-based resins such as rosin, modified rosin, and rosin ester; terpene-based resins such as terpene resins, aromatic-modified terpene resins, hydrogenated terpene resins, and terpene-phenolic resins are used. is there. In the synthetic resin-based tackifying resins, aliphatic (C ₅ series) petroleum resin, aromatic (C ₉
Type) Petroleum resin, copolymer type (C ₅ / C ₉ type) petroleum resin, hydrogenated petroleum resin, petroleum resin such as DCPD type petroleum resin; coumarone / indene resin; pure monomer type such as styrene resin and substituted styrene resin Examples include petroleum resins; phenolic resins such as alkylphenol resins and rosin-modified phenol resins; xylene resins.

Of these, tackifying resins that are liquid at room temperature and tackifying resins that are soluble in the urethane prepolymer can be used as solids, and solid resins having a softening point of 130 are preferred.
It is below ℃.

Examples of the adhesiveness-imparting agent include silane coupling agents (γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, reaction products of both compounds, etc.) and the like.

Examples of the water binder include tosyl isocyanate and zeolite.

As the stabilizer, tinuvin 326 or 2,4
-UV absorbers such as dihydroxybenzophenone, Zn
And metal chelates such as Ni-dibutyldithiocarbamate, azo compounds such as p-hydroxyazobenzene and p-aminoazobenzene, and the like, which are used for the purpose of light stabilization.

As the colorant, inorganic colorants such as titanium oxide, iron oxide, chromium oxide, cadmium sulfate, aluminomagnesium and lamp black, and azo and diazo dyes,
Examples include organic dyes such as phthalocyanine and dioxazine. Although an organic solvent is not required in the present invention, it does not prevent its use.

[0055]

BEST MODE FOR CARRYING OUT THE INVENTION A urethane prepolymer is synthesized,
After transferring to another device, processing into an adhesive, or one device,
Whether the urethane prepolymer synthesis and the processing into the adhesive are both used can be appropriately selected, but an embodiment will be described here by the former method.

According to the first aspect of the invention, in order to improve the adhesiveness of the urethane prepolymer having an isocyanate group terminal, N
-Methyl-2-pyrrolidone is compounded.

After the polyol was charged into a reaction vessel and sufficiently dehydrated under reduced pressure, an excess of 4,4'-diphenylmethane diisocyanate or a polyisocyanate such as a crude product thereof was mixed, and then the usual urethane synthesis conditions (for example, 4 hours at 80 ° C.). ) To react. After cooling, N-methyl-2-pyrrolidone is blended to obtain an adhesive. At this time, other modifiers that are not affected by water (specifically, calcium carbonate, dioctyl phthalate, ultrafine silica powder, etc.) may be added.

According to a second aspect of the invention, in the invention of the first aspect, the compounding ratio of N-methyl-2-pyrrolidone to the urethane prepolymer having an isocyanate group at the end in order to further reduce the viscosity and increase the adhesiveness is: It is 0.1 to 30 parts by mass with respect to 100 parts by mass of the prepolymer.

The embodiments of the inventions of claims 3 and 4 are as follows. The polyether polyol and the polyester polyol may be used alone, but when they are used in combination, a prepolymer having a low viscosity and excellent adhesiveness can be obtained, so a mixed polyol will be used for description. Polyoxypropylene polyol as a polyether polyol, and one or more hydroxyl group-terminated polyols obtained by esterification reaction of adipic acid and ethylene glycol as a polyester polyol are selected and charged into a reactor.
After sufficiently dehydrating under reduced pressure, an excess of 4,4'-diphenylmethane diisocyanate or a polyisocyanate such as a crude product thereof is added, and ordinary urethane synthesis conditions (for example, 80 ° C) are used.
For 4 hours). After cooling, N-methyl-2-pyrrolidone is blended to obtain an adhesive. At this time, other modifiers that are not affected by water (specifically, calcium carbonate, dioctyl phthalate, ultrafine silica powder, etc.) may be added.

Further, in order to make the adhesive obtained above more rapid curable, bis (morpholinoethyl) ether,
Bis (2,6-dimethylmorpholinoethyl) ether,
A urethane curing catalyst selected from bis (3,5-dimethylmorpholinoethyl) ether may be added.

The adhesive thus obtained is placed in a hermetically sealed container such as a cartridge or a pail can under a nitrogen stream. After the storage, the adhesive is taken out by a method such as squeezing out or removing a spatula and applied to the adherend. The coating method shall be appropriately selected according to the bonding work procedure. Usually, it is applied using a comb-like iron.

[0062]

EXAMPLES In order to more specifically show the present invention, examples will be described below based on the embodiments of the invention.

Example 1 300 parts by weight of a bifunctional polypropylene glycol having a molecular weight of 2000 (trade name Takelac P-21: manufactured by Takeda Pharmaceutical Co., Ltd.) and a trifunctional polypropylene glycol having a molecular weight of 3000 (trade name Takelac P) were placed in a 1 L separable flask. -31, manufactured by Takeda Pharmaceutical Co., Ltd.) 10
0 parts by mass, 100 parts by mass of a bifunctional polyester-based polyol having a molecular weight of 2000 (trade name Adekanue F7-67, manufactured by Asahi Denka Kogyo Co., Ltd.) was charged, and the mixture was dehydrated under reduced pressure with stirring at 100 ° C. for 1 hour and then allowed to reach room temperature. When cooled and the liquid temperature drops to 50 ° C, the crude MDI (trade name Sumidule 4
4V-20, manufactured by Sumitomo Bayern Urethane Co., Ltd.) (250 parts by mass) was added and reacted at 80 ° C. for 4 hours to obtain a urethane prepolymer. 750 parts by weight of this prepolymer was transferred to a 5 L planetary mixer and thoroughly dried, heavy calcium carbonate (trade name NS # 2300, manufactured by Nitto Koka Kogyo Co., Ltd.) 5.
00 parts by mass, fine powder silica (trade name RY200, manufactured by Nippon Aerosil Co., Ltd.) 50 parts by mass, and DOP 200 parts by mass were added and mixed sufficiently. 75 parts by mass of N-methyl-2-pyrrolidone was added to obtain a solventless, low-viscosity, one-liquid moisture-curable urethane liquid adhesive composition.

(Example 2) 5 parts by mass of bis (2,6-dimethylmorpholinoethyl) ether (trade name U-CAT2041, manufactured by San-Apro) was blended in the final step of the adhesive of Example 1. The viscosity value was about the same as in Example 1.

(Comparative Example 1) N-methyl-2-pyrrolidone (NMP) was not compounded in the final step of the adhesive of Example 1.

Comparative Example 2 Example 1 was repeated except that a petroleum hydrocarbon solvent (trade name: Shellzol 71, manufactured by Shell Japan) was used instead of NMP.

[0067]

[Table 1]

(Comparative Example 3) Example 2 was followed except that a petroleum hydrocarbon solvent (trade name: Shellzol 71, manufactured by Shell Japan) was used instead of NMP.

The formulations of Examples 1 and 2 and Comparative Examples 1, 2 and 3 are shown in Table 1.

The coating liquid workability (viscosity and viscosity), adhesiveness and quick-curing property of the one-pack moisture-curable urethane adhesive composition thus obtained were evaluated by the following methods.

The coating workability (viscosity and viscosity) is the viscosity and viscosity of the composition (thixotropic index;
It is called "TI value". ). That is, the viscosity (23 ° C.) of the B-type rotational viscometer at rotational speeds of 20 r / min and 2 r / min was measured, and further measured at 2 r / min / 20.
r / min = TI value was calculated. Furthermore, the practical coating workability was evaluated by the lightness of the troweling when actually coating with a comb-like iron. The evaluation was made into three grades of ◯, Δ and ×.
Here, ◯ means good, Δ means good, and × means bad, and x means that it cannot be put to practical use. The TI value serves as an index of good or bad coating workability, and the larger the value, the better the coating workability such as trowel separation.

Adhesiveness is 22 ± 1 ° C., 55 ± 5% RH
A flexible board with a thickness of 8 mm and a thickness of 1.5 mm, a width of 25 mm, and a length of 150, which are adjusted to (standard conditions) indoors.
mm soft PVC sheet and the above adhesive composition were left to stand from the day before, and were applied to the flexible board on the filament so that the application amount was about 250 g / m ² with a comb iron, and after 30 minutes, the above Put the PVC sheets together, and after curing for 3 days,
The 90-degree peel adhesive strength was measured at a pulling speed of 50 mm / min, and the adhesive strength at that time and the rupture state were compared. When the breaking position is the adhesive layer, the adhesiveness to the adherend is good, but at the interface between the adherend and the adhesive, it can be judged that the adhesiveness is bad.

The fast curing property was evaluated by the time until tack free.

That is, the adhesive composition was applied under the same conditions as in the adhesiveness evaluation, and the time (tack free time) until no tack was felt by touching with a finger was determined. The shorter the tack-free time, the faster the curing.

Table 2 shows the evaluation results of coating workability, adhesiveness, and rapid curing property.

From the results shown in Table 2, in the examples, both 1 and 2 have low viscosities, and the TI value, which is an index representing the structural viscosity, which is the viscosity ratio of 2r / min and 20r / min, is large. The workability was good. In Comparative Example 1, the viscosity was extremely high, the troweling was very heavy, and the coating operation was not practically endurable. Further, in Comparative Examples 2 and 3, a low viscosity was obtained and a relatively large TI value was obtained, but the adhesiveness was far insufficient, and especially in Comparative Example 2, the tack tally time was long.

[0077]

[Table 2]

The results of the adhesiveness show that all the examples have a value of 20.
While the adhesive strength exceeding 00 N / m was expressed, in Comparative Example 1 having a high viscosity, about half the adhesive strength was obtained, but in Comparative Examples 2 and 3, the adhesive strength was further lowered, The position of the break also became the interface between the soft PVC sheet and the flexible board, resulting in poor adhesion.

In the examples, the time to tack-free in terms of fast curability was as short as 30 to 50 minutes, showing a fast curability comparable to that of the solvent type.

On the other hand, in Comparative Example 1 and Comparative Example 2,
It took 80 to 90 minutes to be tack-free and was inferior in quick-curing property. Further, in Comparative Example 3, although the time until becoming tack-free was shortened due to the effect of the catalyst, good adhesiveness was not obtained as in the other Comparative Examples.

[0081]

As described above, the one-component moisture-curable urethane liquid type adhesive composition of the present invention can be used as a solventless adhesive containing no low- to medium-boiling organic solvent. Compared with the conventional solvent-free one-component moisture-curable urethane adhesive, a low-viscosity adhesive composition is obtained, and since it exhibits a structural viscosity excellent in coating workability such as comb-like iron at room temperature, The coating work can be easily performed. Regarding the bonding work, it has fast curing property, good adhesive strength,
Particularly, it exhibits excellent adhesiveness to difficult-to-adhere materials such as metal, rubber and plastic.

Continuation of front page (51) Int.Cl. ⁷ identification code FI C08G 18/48 C08G 18/48 Z (56) Reference JP-A 63-120721 (JP, A) JP-A 5-117619 (JP, A) ) JP-A-7-145366 (JP, A) JP-A-10-1607 (JP, A) JP-A-10-25463 (JP, A) JP-A-2-99578 (JP, A) Special Table 8- 511054 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C09J 4/00-201/10 C08G 18/00-18/87

Claims (3)

(57) [Claims] 1. An isocyanate powder having a molecular weight of 2000 or more.
With respect to 100 parts by mass of the urethane prepolymer at the end, 0.
A one-component moisture-curable urethane liquid-type adhesive composition comprising 1 to 30 parts by mass of N-methyl-2-pyrrolidone and having low viscosity and high adhesiveness. 2. An isocyanate-terminated urethane prepoly
Are polyoxypropylene polyols and polyhydric alcohols.
The poly obtained by the reaction of rucor with polycarboxylic acid
Obtained by ester polyols and polyisocyanates
Is an isocyanate-terminated urethane prepolymer
Characterized by low viscosity and excellent balance of adhesive function
The one-component moisture-curable urethane-based liquid type adhesive composition according to claim 1 . 3. The one-part moisture-curable urethane liquid type adhesive composition according to claim 1 or 2 , wherein bis (morpholinoethyl) ether, bis (2,6-dimethylmorpholinoethyl) ether, bis A one-pack moisture-curable urethane-based liquid-type adhesive composition comprising a mixture of one or more amine compounds selected from (3,5-dimethylmorpholinoethyl) ether and having a high fast-curing property.