JPH11263963A - One-pack type moisture-curable urethane liquid type adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one pack type moisture-curable liquid urethane adhesion composition that can attain early development of initial tack with which a conventional composition of the same type has a problem, has excellent coating workability and can impart excellent adhesion properties. SOLUTION: As an adhesive composition that manifests excellent action effect with an excellent balance between the viscosity reduction and the adhesion of the urethane prepolymer, is obtained a one-can and moisture-curing type urethane liquid type adhesion composition that early manifests excellent initial tack and can be cold coated by allowing a combination of a polyether polyol with a polyester polyol to react with polyisocyanate, namely the resultant urethane polymer bearing isocyanate chain terminals where a part of these polyols is replaced with hydroxyl-containing xylene resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component moisture-curable urethane-based adhesive composition which exhibits a low-viscosity liquid property even though it is solvent-free.

[0002]

2. Description of the Related Art A one-component moisture-curable urethane-based adhesive mainly comprises a urethane prepolymer having an isocyanate group at a terminal (hereinafter, referred to as a "prepolymer"), and the isocyanate group is exposed to moisture in the air or a coating. The adhesive layer is formed by reacting with moisture in the adherend to cure and crosslink, thereby bonding various adherends. This adhesive includes a reactive hot-melt adhesive used in a solid state and a room temperature-curable liquid adhesive used in a liquid state.

Conventionally, a moisture-curable urethane adhesive which is a one-part liquid and is curable at room temperature (hereinafter abbreviated as "moisture-curable urethane adhesive") is used in the presence or use of an organic solvent. Without reacting polyols and excess isocyanates, a urethane prepolymer having terminal isocyanate groups is synthesized, and if necessary, a filler, an organic solvent, a thixotropic agent, a curing catalyst, etc. are compounded. The adhesive was used at room temperature using an appropriate applicator.

[0004] Among the one-component moisture-curable urethane-based adhesives, in the case of a solvent type, since a large amount of a volatile organic solvent is used for dilution, the molecular weight of the urethane prepolymer may be extremely large. Therefore, the initial adhesiveness that is developed immediately after the organic solvent evaporates can be an initial tackiness state (hereinafter, referred to as “initial tack”) that is superior to the properties of the high molecular polymer.

Further, as a characteristic of the solvent type, since the organic solvent assists the wettability necessary for adhesion, which is a disadvantage of the high molecular polymer, in both the wetting effect and the dilution effect, the adhesiveness is also good.

[0006] The organic solvent used in the one-component solvent-type moisture-curable urethane-based adhesive has a boiling point of 100, typified by ethyl acetate, methyl ethyl ketone, methylene chloride, etc., in order to quickly develop the initial tack and obtain the strength. So-called low-boiling solvents having a boiling point of 100 ° C or lower or so-called medium-boiling solvents having a boiling point of 100 ° C to 150 ° C, such as toluene, xylene, and methyl isobutyl ketone, are generally used. A high-boiling point solvent, a plasticizer, and the like are used only in an auxiliary manner as needed, since drying is delayed.

[0007] These solvents have a serious problem of odor and the effect on the health of workers due to volatilization of the solvent at the time of coating operation, and it is important to pay attention to fire prevention because it is a flammable dangerous substance. In addition, they are subject to laws and regulations such as the Fire Service Act and are subject to restrictions on their storage quantity.

[0008] As described above, the one-component solvent type moisture-curable urethane-based adhesive has the speed and strength of initial tack and good adhesiveness, but in today's society, it is dangerous and harmful based on organic solvents. It is well known that this is the biggest difficulty with this adhesive. The solution to the difficulty is to eliminate the solvent, but simply eliminating the organic solvent to zero does not realize an excellent adhesive. In other words, the adhesive is required to develop a high initial tack as early as possible,
The urethane prepolymer needs to be in a liquid state, and when using a prepolymer having a molecular weight as large as possible within the range, firstly, the coating operation is difficult, and secondly, the high molecular weight polymer has poor wettability. Therefore, there is a technical difficulty that no adhesive property comparable to the solvent type is obtained.

[0009] Actually, the conventional one-package, solvent-free, moisture-curable urethane-based adhesives have to use a low-molecular-weight prepolymer, so that they have poor initial tack and are slow to develop. Is pointed out. In addition, in order to provide coating workability, it is necessary to dilute with some organic solvent in reality. However, there is still a problem that the structure viscosity is poor and the coating workability such as coating with a trowel is inferior. In addition, since the adhesiveness is poorer than that of the solvent type, at present, both the adhesiveness and the adhesive strength are inferior to metals, rubbers, plastics and other difficult-to-adhere materials.

[0010] In the above invention, the inventors of the present invention, as a separate invention, reduce the viscosity, which is a drawback of the conventional one-component solvent-free, moisture-curable adhesive composition, to lower the viscosity, increase the dilutability, and improve the coating workability. As an improvement, a technique of blending N-methyl-2-pyrrolidone (hereinafter abbreviated as “NMP”) with an isocyanate-terminated urethane prepolymer has been developed, but it is more excellent in early onset of initial tack. There is also a need for a one-component, non-solvent, moisture-curable adhesive composition.

[0011]

SUMMARY OF THE INVENTION The present invention meets the above-mentioned demands and provides an early stage of initial tack which is a drawback of a conventional solvent-free, liquid, room temperature-curable, one-part, moisture-curable adhesive. Accordingly, it is an object of the present invention to provide a one-component moisture-curable urethane-based adhesive composition having good application workability and further excellent adhesion.

[0012]

The present inventors have developed a liquid, room temperature-curable, one-part moisture-curable adhesive composition using a solvent-free urethane prepolymer, particularly a low-pressure urethane prepolymer. After examining those which exhibit an excellent action and effect to improve the balance between viscosity and adhesion, it is found that the urethane prepolymer having an isocyanate terminal by the urethane reaction of a specific polyether polyol and a specific polyester polyol in combination with a polyisocyanate. Was found. Further, when the improvement of the initial tack was further sought in this excellent liquid type one-part moisture-curable adhesive composition, a part of these polyols was converted to a hydroxyl group-containing xylene resin, whereby an excellent initial tack was obtained. The present inventors have found that early expression can be obtained and completed the present invention. The liquid of the present invention has a viscosity that allows easy application with a suitable applicator such as a comb-shaped iron at room temperature without heating.

Further, as described above, N-methyl-2-
By using pyrrolidone in a one-part moisture-curable adhesive composition, it has been found that it provides excellent dilutability and imparts excellent adhesiveness, and further improves the object of the present invention. Completed the invention.

That is, means for solving the above-mentioned problems of the present invention are as follows. In the invention of claim 1,
In an isocyanate-terminated urethane prepolymer obtained by a urethane reaction of a polyether polyol and a polyester polyol with a polyisocyanate, the initial tack of a part of the polyether polyol and the polyester polyol as a hydroxyl group-containing xylene resin is excellent, and at room temperature, It is a one-component moisture-curable urethane-based liquid type adhesive composition that can be applied.

According to a second aspect of the present invention, in the first aspect, the hydroxyl group-containing xylene resin is an addition condensation oligomer of meta-xylene and formaldehyde and / or a modified product thereof. It is a liquid moisture-curable urethane liquid type adhesive composition.

According to a third aspect of the present invention, there is provided a low-viscosity composition obtained by further mixing N-methyl-2-pyrrolidone with the one-part moisture-curable urethane liquid adhesive composition of the first or second aspect. A one-part, moisture-curable urethane-based liquid-type adhesive composition that can be applied at room temperature and has high adhesiveness.

In the present invention, the hydroxyl group-containing xylene resin exhibiting excellent action hardening for improving the initial tack includes a xylene formaldehyde resin synthesized from xylene and formaldehyde, a mesitylene formaldehyde resin synthesized from mesitylene and formaldehyde, and Modified xylene formaldehyde resin modified with a third component such as phenol. Among them, an oligomer of meta-xylene (m-xylene among the structural isomers of xylene) and formaldehyde, and an oligomer obtained by reacting the third component with the oligomer are suitable for the purpose of the present invention.
The third component mentioned here includes polyol, alkylphenol, phenol, epoxy resin and the like.

In the present invention, the proportion of the hydroxyl group-containing xylene resin which replaces the polyether polyol and the polyester polyol is 1% by mass to 80% by mass.
When the amount is less than 1% by mass, the effect of the xylene resin on imparting the initial tack is not sufficiently obtained. When the amount is more than 80% by mass, the effect of the initial tack is sufficiently exhibited, but the viscosity of the prepolymer becomes high. And lacks practicality as an adhesive. The range in which the effect of imparting the initial tack of the xylene resin can be sufficiently exhibited is particularly preferably from 5% by mass to 60% by mass.

The polyol which is a preferable starting material of the urethane prepolymer of the present invention can be classified into a polyether polyol and a polyester polyol. That is, examples of the polyether polyol having an ether bond in the molecule include polyoxyalkylene diols (specifically, polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, and copolymers thereof), polyoxyalkylenes Polyoxyalkylene polyols such as triols (specifically, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. and glycerin, trimethylolpropane, etc.) and other bisphenols;
Examples thereof include diols, polyether polyols, and polyoxytetramethyl glycol obtained by ring-opening polymerization of tetrahydrofuran to which ethylene oxide or propylene oxide is added using sugars, amines, or the like as a starting material.

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

As the polyester polyol, a conventionally known polyester polyol can be widely used as long as it is a compound having an ester bond as a repeating unit in the molecule and having a terminal hydroxyl group. Specifically, a condensation-based polyester polyol obtained by dehydration condensation of a polyhydric 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 the following; a polycarbonate diol obtained by phosgenation of a polyol or a transesterification reaction with diphenylene carbonate; a polyester polyol obtained by a polyaddition reaction between a polycarboxylic anhydride and diepoxide;
Examples thereof include urethane-modified polyester polyols in which a urethane group or the like is introduced into the molecule.

Among them, ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-
It is preferable to use a condensation polyester polyol obtained by a condensation reaction between a polyhydric alcohol such as hexanediol and neopentyl glycol and a polycarboxylic acid such as adipic acid, sebacic acid, isophthalic acid, and trimellitic acid.

In addition to the above compounds, conventionally known compounds which can be used as a so-called polyol having a hydroxyl group in the molecule can be used. Specifically, hydroxyl-terminated polybutadiene (1,2-adduct, 1,4-adduct), a so-called rosin-modified polyol having a rosin skeleton in the molecule, a polyol having an amine structure in the molecule, carbinol-modified silicone oil So-called silicon-based diols in which carbinol is introduced into both ends of a polysiloxane, so-called acrylic polyols having an acrylate (including methacrylate) skeleton, and a fluorinated resin (for example, difluoride) So-called fluororesin-based polyols having a hydroxyl group at the terminal of ethylene-acrylic copolymer resin) can be exemplified.

As the polyisocyanate used in the present invention, an aliphatic, aromatic or alicyclic polyisocyanate compound having a plurality of, preferably an average of 2 to 3 isocyanate groups in a molecule 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, referred to as
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 (4,4'- A crude product of MDI, hereinafter referred to as “polymeric MDI” or “crude MDI”), hexamethylene diisocyanate (hereinafter, referred to as “methylene MDI”)
"HMDI". ), Xylene diisocyanate (hereinafter referred to as “XDI”), meta-xylene diisocyanate, 1,5-naphthalenediisocyanate, hydrogenated TDI, hydrogenated MDI, hydrogenated XDI, isophorone diisocyanate, and other isocyanate compounds; Sumidur N (Sumitomo Bayer) Burette polyisocyanate compounds such as Urethane Co .; polyisocyanate compounds having an isocyanate ring such as Desmodur IL, HL (manufactured by Bayer AG) and Coronate EH (manufactured by Nippon Polyurethane Industry Co., Ltd.); Sumidur L (Sumitomo) And adduct polyisocyanate compounds such as Coronate HL (manufactured by Nippon Polyurethane Industry Co., Ltd.).

Among them, 4,4′-MDI and their crude products, a mixture of 4,4′-MDI and 2,4′-MDI and their crude products are used to obtain the initial tack strength, It is preferable in terms of adhesiveness, adhesive strength, and good coating workability.

The isocyanate-terminated urethane prepolymer is usually synthesized by reacting the above polyols with an excess of polyisocyanate. There is no particular limitation on the synthesis method, and it may be produced by a conventionally known method.

The term “excess polyisocyanate” as used herein means that the isocyanate group equivalent is excessive compared to the hydroxyl group equivalent of the polyol, and the equivalent relation is NCO / O.
It can be represented by the H ratio. That is, theoretically NCO
If the / OH ratio exceeds 1, the terminal may be an isocyanate terminal, but since the present invention is characterized by being liquid, the NCO / OH ratio is usually preferably 1.5 or more. NCO / O
Although the upper limit of the H ratio is not particularly limited, NCO /
The OH ratio is preferably 10.0 or less. The reason for this is that NCO /
If the OH ratio exceeds 10.0, the isocyanate group becomes excessive, which causes adverse effects such as delay in curing and increase in foaming during moisture curing. Furthermore, in order to lead to a liquid and low-viscosity prepolymer, the type of polyol, the number of functional groups,
In consideration of the molecular weight, etc., the NCO / OH ratio is set to 2.0 to
It is particularly preferred to adjust to 10.0.

Although the urethane reaction temperature and the reaction time are not particularly limited, it is usually preferable to mix the polyol and the polyisocyanate under a nitrogen stream and then to react at 60 to 100 ° C. for 3 to 8 hours. In the reaction, an appropriate amount of an organometallic urethane catalyst such as dibutyltin dilaurate may be added at any stage.

In the present invention, N-methyl-2 used in combination
-Commercially available pyrrolidone may be used as it is, but in order to obtain long-term storage stability, it is preferable to remove water with a commercially available dehydrating agent such as molecular sieve or silica gel. The compounding amount of N-methyl-2-pyrrolidone is preferably 0.1 to 30 parts by mass based on 100 parts by mass of the prepolymer. When the amount is less than 0.1 part by mass, the effect of the present invention is hardly obtained, and when the amount is more than 30 parts by mass, the time until the initial tack is developed is long, and the curing is delayed. The most preferable range in which the effects of the present invention are most remarkably exhibited is 0.5 to 30 parts by mass.

When N-methyl-2-pyrrolidone is added to the one-component moisture-curable urethane liquid adhesive composition of the present invention, the N-methyl-2-pyrrolidone may be added at any time during the urethane prepolymer synthesis process. You may. However, since N-methyl-2-pyrrolidone easily absorbs water, it is more preferable to be in the process of producing an adhesive that is less affected by moisture. Most preferably, it is blended in the final production step of the adhesive.

The production process of the one-pack moisture-curable urethane-based liquid adhesive composition of the present invention is as follows. It is manufactured by mixing and processing various modifiers such as an agent, a plasticizer, a diluent, a tackifier resin, an adhesion promoter, a curing catalyst, a moisture binder, a stabilizer, a colorant, and an organic solvent.

Since this adhesive is destabilized by the influence of moisture during the manufacturing process and during storage, it is necessary to remove as much moisture as possible from the raw material having moisture in the compounding raw material, so that the long-term quality stability of the adhesive can be improved. It is preferable for obtaining.

As the above-mentioned inorganic filler, an inorganic compound which can be industrially used as a filler, such as calcium carbonate, clay, talc, magnesium oxide, diatomaceous earth, and glass balloon, can be appropriately used.

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

Examples of the plasticizer include dioctyl phthalate, dibutyl phthalate, dilauryl phthalate,
Butylbenzyl phthalate, dioctyl adipate, diisodecyl adipate, trioctyl phosphate,
Mineral spirit and the like can be mentioned, and each can be used alone or in combination.

Examples of the diluent include petroleum hydrocarbon diluents and esters such as 3-methyl-3-methoxybutyl acetate and dimethyl glutarate. As the tackifying resin, a conventionally known resin can be used.
Specifically, for example, in the case of natural resin-based tackifying resins, rosin-based resins such as rosin, modified rosin, and rosin ester; and terpene-based resins such as terpene resin, aromatic modified terpene resin, hydrogenated terpene resin, and terpene phenol resin are used. is there. In the case of a synthetic resin-based tackifying resin, an aliphatic resin (C ₅
Petroleum resin, aromatic (C ₉ ) petroleum resin, copolymer (C ₅ / C ₉ ) petroleum resin, hydrogenated petroleum resin, DCP
Petroleum resins such as D-based petroleum resins; Coumarone-indene resins;
Pure monomeric petroleum resins such as styrene resins and substituted styrene resins; phenolic resins such as alkylphenol resins and rosin-modified phenolic resins; xylene resins;

Among them, a tackifying resin which is liquid at normal temperature and a tackifying resin which can be dissolved in a urethane prepolymer when solid can be used, and a solid resin having a softening point of preferably 130
It is below ° C.

Examples of the adhesion-imparting agent include silane coupling agents (γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, a reaction product of both compounds, and the like).

Examples of the curing catalyst include bis (morpholinoethyl) ethers such as bis (morpholinoethyl) ether, bis (2,6-dimethylmorpholinoethyl) ether, bis (3,5-dimethylmorpholinoethyl) ether and the like. An amine-based urethane catalyst, an organometallic-based urethane catalyst such as dibutyltin dilaurate, or the like can be appropriately used depending on the purpose.

Examples of the water binder include tosyl isocyanate and zeolite.

As stabilizers, tinuvin 326, 2,4
An ultraviolet absorber such as dihydroxybenzophenone, Zn
And metal chelates such as Ni-dibutyldithiocarbamate, and azo compounds such as p-hydroxyazobenzene and p-aminoazobenzene. These are used for the purpose of light stabilization.

Examples of the coloring agent include inorganic coloring agents such as titanium oxide, iron oxide, chromium oxide, cadmium sulfate, alumino magnesium, lamp black, and azo and diazo dyes.
Organic dyes such as phthalocyanine and dioxazine are exemplified. Although the organic solvent is not required in the present invention, it does not prevent its use.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION The synthesis of a urethane prepolymer will be described according to the claims. The polyether polyol and the polyester polyol may be used alone, but a combination of the two will give a prepolymer having low viscosity and excellent adhesiveness.

According to the first aspect of the present invention, a polyoxypropylene polyol as a polyether polyol, a hydroxyl-terminated polyol obtained by subjecting adipic acid and ethylene glycol to an esterification reaction as a polyester polyol, and a xylene resin having a hydroxyl group are introduced into a reactor. Charge, add an excess of polyisocyanate such as 4,4'-MDI or a crude product thereof, react under ordinary urethane synthesis conditions (eg, 80 ° C for 4 hours), and cool to obtain an adhesive.

According to the second aspect of the present invention, the hydroxyl group-containing xylene resin of the first aspect of the present invention comprises:
An addition condensation oligomer of meta-xylene and formaldehyde and / or a modified product thereof.

In the invention according to the third aspect, similarly to the above, a polyoxypropylene polyol as a polyether polyol, a hydroxyl-terminated polyol obtained by esterifying adipic acid and ethylene glycol as a polyester polyol, a xylene resin containing a hydroxyl group Is charged into a reactor, and an excess of polyisocyanate such as 4,4′-MDI or a crude product thereof is added, and reacted under ordinary urethane synthesis conditions (for example, at 80 ° C. for 4 hours). After cooling, N-methyl-2-pyrrolidone is blended to obtain an adhesive.

The adhesive thus obtained is housed in a hermetically sealable container such as a cartridge or a pail under a stream of nitrogen. After storage, the adhesive is taken out by a method such as squeezing out or removing a spatula, and applied to the adherend. The application method is appropriately selected according to the procedure of the bonding operation. Further, if necessary, various modifiers can be blended to form a composition.

[0049]

EXAMPLES Hereinafter, examples will be described based on the embodiments of the present invention in order to more specifically illustrate the present invention. In addition, although the adhesive composition which mix | blended various modifiers after a urethane prepolymer synthesis | combination is described in an Example, this invention is not limited to these Examples. (Example 1) Bifunctional polypropylene glycol having a molecular weight of 2,000 (trade name: Takelac P-21: manufactured by Takeda Pharmaceutical Co., Ltd.) 50 which was previously dehydrated in a 5 L planetary mixer.
0 parts by mass, 100 parts by mass of a trifunctional polypropylene glycol having a molecular weight of 3000 (Takelac P-31, manufactured by Takeda Pharmaceutical Co., Ltd.), and a bifunctional polyester-based polyol having a molecular weight of 2000 (Adeka New Ace F7-6)
7, 200 parts by mass of Asahi Denka Kogyo Co., Ltd.), 200 parts by mass of a hydroxyl group-containing xylene resin (trade name: Nicanol H, manufactured by Mitsubishi Gas Chemical Company), and 4,4-MD
A mixture of I and 2,4'-MDI (trade name: Lepranate M
I: BSF Japan Co., Ltd.) (591 parts by mass) was added, and a urethane-forming reaction was performed at 90 ° C. for 4 hours. The urethane reaction conditions at this time are as follows: NCO content 10%, NCO
The / OH ratio was 5.1. After cooling to room temperature, the calcium carbonate previously dehydrated (trade name: Calfine 100:
1000 parts by mass (manufactured by Maruo Calcium Co., Ltd.) and 400 parts by mass of DOP are added, and 10 parts by mass of bis (2,6-dimethylmorpholinoethyl) ether (trade name: U-CAT2041: manufactured by San Apro) are added to obtain a solventless type. A one-component moisture-curable urethane liquid adhesive composition was obtained.

Example 2 100 parts by mass of N-methyl-2-pyrrolidone were added to the adhesive composition obtained above, and a solvent-free one-part moisture-curable urethane-based liquid-type adhesive was used. A composition was obtained. However, the amount of DOP was reduced by the amount of N-methyl-2-pyrrolidone to 300 parts by mass.

(Example 3) As a polyester polyol, 200 parts by mass of a bifunctional polyester-based polyol having a molecular weight of 1,000 (trade name: Adeka New Ace F7-68: manufactured by Asahi Denka Kogyo KK) was charged.
4,4′-MDI so that the CO / OH ratio is 4.4
And a mixture of 2,4'-MDI (trade name: Luplanate M)
I: manufactured by BSF Japan Co., Ltd.), except that 627 parts by mass was added, to obtain a solvent-free, one-component moisture-curable urethane liquid adhesive composition in the same manner as in Example 1.

Example 4 To the adhesive composition obtained in Example 3 was added 100 parts by mass of N-methyl-2-pyrrolidone, and a one-liquid, moisture-curable, urethane-based liquid type, which was also solvent-free, was used. An adhesive composition was obtained. However, the amount of DOP was reduced by the amount of N-methyl-2-pyrrolidone to 300 parts by mass.

Comparative Example 1 In the production process of Example 1, no hydroxyl group-containing xylene resin was used for the polyol. At this time, the urethane reaction conditions are such that the NCO content is 1
At 0%, the NCO / OH ratio was 4.8.

[0054]

[Table 1]

Comparative Example 2 In the production process of Example 2, no hydroxyl group-containing xylene resin was used for the polyol. At this time, the urethane reaction conditions are such that the NCO content is 1
At 0%, the NCO / OH ratio was 4.8.

(Comparative Example 3) In the production process of Example 2, the hydroxyl-containing xylene resin was not used for the polyol.
Instead of N-methyl-2-pyrrolidone, a petroleum hydrocarbon solvent (trade name: Shellsol 71, manufactured by Shell Japan) was used. The urethane reaction conditions at this time were NCO
The content was 10% and the NCO / OH ratio was 4.8.

Comparative Example 4 In the production process of Example 4, no hydroxyl group-containing xylene resin was used for the polyol.
As the polyester polyol, a bifunctional polyester-based polyol having a molecular weight of 1,000 (trade name: ADEKA NEW ACE F7-68: manufactured by Asahi Denka Kogyo KK) was used. At this time, the urethane reaction conditions are such that the NCO content is 10%,
The / OH ratio was 4.1.

Examples 1, 2, 3, 4 and Comparative Examples 1, 2,
Table 1 shows the formulations of Nos. 3 and 4.

With respect to the one-part moisture-curable urethane-based adhesive composition thus obtained, the coating workability (viscosity and viscosity), initial tack (onset time and width), and adhesiveness were determined by the following methods. evaluated.

The coating workability (viscosity and viscosity) was evaluated based on the viscosity and viscosity (thixotropic index, hereinafter referred to as “TI value”) of the composition. That is, the viscosity (23 ° C.) at a rotational speed of 20 r / min and 2 r / min of a B-type rotational viscometer was measured, and further measured at 2 r / min / min.
20r / min = TI value was calculated. The TI value is an index of whether coating workability is good or bad, and a larger value generally indicates better coating workability such as ironing, but it depends on the magnitude of viscosity. is not. Further, practical application workability was evaluated by lightness of ironing when actually applying with a trowel. The evaluation was made in three stages of ○, Δ, and ×.は means good, 可 means good, and × means bad. △ means that ironing is heavy, but can be used practically, and × means that ironing is too heavy for practical application.

Adhesion was measured under standard conditions (22 ± 1 ° C., 55 ± 1
5% RH, indoors adjusted to 8mm thick and 30m wide
m, a flexible board having a length of 100 mm and a thickness of 1.
A commercially available flexible PVC sheet for flooring material of 5 mm, width of 25 mm and length of 150 mm, and the above adhesive composition were left to stand from the day before, and were plied into a filament so as to have an application amount of about 250 g / m ² with a comb iron. After applying to the board, after 30 minutes elapse, the previous PVC sheet was glued and cured under standard conditions for 3 days, then the peeling strength at 90 ° was measured at a pulling speed of 50 mm / min, and the bonding strength and the breaking condition at that time were compared. did. If the position of the break is the adhesive layer, the adhesiveness to the adherend is good, but if it is at the interface between the adherend and the adhesive, it can be determined that the adhesiveness is poor.

The onset time and the width of the initial tack were adjusted in a room adjusted to standard conditions (22 ± 1 ° C., 55 ± 5% RH) in a flexible board having a thickness of 4 mm and a thickness of 1.5 m.
m, 25 mm in width, 150 mm in length, a commercially available flexible PVC sheet for flooring, and the above adhesive composition were allowed to stand from the previous day, and were plied into a filament so that the coating amount was about 250 g / m ² with a comb-shaped iron. Apply to board, 10 minutes, 20 minutes, 30 minutes
Minutes, 40 minutes, 50 minutes and 60 minutes after the previous PVC sheet was pasted together and immediately peeled off by hand, the initial tack, that is, the adhesiveness of the adhesive film or the appearance of thread-like stickiness, and the resistance Observation was made and evaluated in three grades of ○, Δ, and ×.は indicates good, 可 indicates acceptable, and × indicates unacceptable. △ indicates that there is no practical problem, and ○ indicates that a good initial setting is obtained.

Table 2 shows the evaluation results of the coating workability, the initial tack, and the adhesiveness.

From the results in Table 2, it can be seen that the examples show low viscosity at 20 r / min over all of 1, 2, 3, and 4 and 2 r
The TI value, which is an index representing the structural viscosity, which is a viscosity ratio of 20 r / min to 20 r / min, also showed a large value, and ironing was good. Also, all the examples have a large adhesive strength,
Breakage also occurred in the adhesive layer, indicating good adhesion to the adherend. Furthermore, the initial tack appears from about 20 minutes under standard conditions, and still shows good tack even after 60 minutes,
When the adherends were bonded together in this state, the adherence of the adherends was good.

[0065]

[Table 2]

On the other hand, in Comparative Examples 1, 2 and 4,
Although good coating workability is not obtained, the initial tack starts to appear in 20 minutes, but the width is short, which significantly limits the bonding work, and is not practical in actual coating work. It became. In Comparative Example 3, there was no practicality as an adhesive except for the workability of coating.

[0067]

As described above, the one-component moisture-curable urethane-based liquid adhesive composition of the present invention can be used as a solventless adhesive containing no low- or medium-boiling organic solvent. Particularly, as compared with a conventional solvent-free, one-component moisture-curable urethane-type adhesive, it has excellent initial adhesiveness and expresses a high initial tack. In addition, a low-viscosity adhesive composition is obtained, and a structural viscosity excellent in application workability such as a comb-shaped iron at room temperature is exhibited, so that the application operation can be easily performed.
Regarding the bonding work, in addition to the above-mentioned initial tack, it has a quick-curing property and a good bonding strength, and exhibits particularly excellent bonding properties to hard-to-bond materials such as metals, rubbers and plastics.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08G 18/54 C08G 18/54

Claims (3)

[Claims] 1. An isocyanate-terminated urethane prepolymer obtained by a urethane reaction between a polyether polyol and a polyester polyol and a polyisocyanate, and has an excellent initial tack when a part of the polyether polyol and the polyester polyol is a hydroxyl group-containing xylene resin. A one-part moisture-curable urethane-based liquid-type adhesive composition that can be applied at room temperature. 2. The one-pack moisture-curable urethane-based urethane resin according to claim 1, wherein the hydroxyl group-containing xylene resin is an addition condensation oligomer of meta-xylene and formaldehyde and / or a modified product thereof. Liquid type adhesive composition. 3. The one-part moisture-curable liquid-type adhesive composition according to claim 1 or 2, further comprising N-methyl-2-pyrrolidone, and having a low viscosity, a high structural viscosity and a high viscosity. 3. The one-component moisture-curable urethane liquid adhesive composition according to claim 1 or 2, wherein the composition is adhesive.