One-component moisture-curing adhesive

Abstract

To provide a one-component moisture-curing adhesive that has good adhesive strength to many different types of substrates, regardless of the substrate. [Solution] A one-component moisture-curing adhesive containing a urethane prepolymer A, wherein the urethane prepolymer A is a urethane prepolymer obtained by reacting a hydroxyl group-containing compound (A1) with an aromatic isocyanate (A2), the hydroxyl group-containing compound (A1) is a polyol having at least one of an ester bond and a CC double bond, and the number average molecular weight of the urethane prepolymer A is in the range of 1,000 to 4,000.

Description

Technical Field

[0001] The present invention relates to a one-component moisture-curing adhesive.

Background Art

[0002] Conventionally, floor materials such as synthetic resin floor materials may be adhered to the floor surface. For adhering floor materials, a one-component moisture-curing adhesive may be used. Specifically, a one-component polyurethane adhesive may be used for adhering floor materials (see, for example, Patent Document 1). The one-component polyurethane adhesive reacts with moisture in the air, cures, and adheres.

[0003] Here, depending on the type of adherent, a desired adhesive strength may not be obtained. For example, adhesive strength may be obtained with a certain adherent, but little adhesive strength may be obtained with a different adherent. Thus, the conventional one-component polyurethane adhesive has not been able to obtain sufficient adhesive strength depending on the type of floor material as the adherent. That is, there is a problem that it may not be possible to cope with a wide range of adherents.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention solves the above problems, and an object thereof is to provide a one-component moisture-curing adhesive having good adhesive strength for many different types of adherents regardless of the adherent.

Means for Solving the Problems

[0006] Depending on the type of substrate, some one-component moisture-curing polyurethane adhesives have low adhesive strength. For example, some one-component moisture-curing adhesives do not have sufficient adhesive strength to rubber or olefin-based substrates. Therefore, the inventors of this invention, through trial and error, have found a one-component moisture-curing adhesive that has good adhesive strength to various types of substrates, regardless of the substrate.

[0007] The one-component moisture-curing adhesive of the present invention contains a urethane prepolymer A. The urethane prepolymer A is a urethane prepolymer obtained by reacting a hydroxyl group-containing compound (A1) with an aromatic isocyanate (A2). The hydroxyl group-containing compound (A1) is a polyol having at least one of an ester bond and a CC double bond. The number-average molecular weight of the urethane prepolymer A is in the range of 1,000 to 4,000. [Effects of the Invention]

[0008] According to the present invention, a one-component moisture-curing adhesive having good adhesive strength regardless of the adherend can be provided. [Modes for carrying out the invention]

[0009] The one-component moisture-curing adhesive according to an embodiment of the present invention contains a urethane prepolymer A obtained by reacting a hydroxyl group-containing compound (A1) with an aromatic isocyanate (A2). The number-average molecular weight of the urethane prepolymer A in the present invention is in the range of 1,000 to 4,000. When the number-average molecular weight is within the above range, the urethane prepolymer A exhibits good reactivity in the one-component moisture-curing adhesive, and the prepolymer is sufficiently crosslinked. It is preferable that the molecular chain is not too long (the number-average molecular weight is not too large) and an appropriate crosslinking density is obtained, so it is preferable that it is within the above range. The molecular weight is preferably in the range of 1,200 to 3,500, and more preferably in the range of 1,400 to 2,000.

[0010] The hydroxyl group-containing compound (A1) is a polyol having at least one of an ester bond and a CC double bond. Studies have shown that polyols having at least one of an ester bond and a CC double bond tend to have improved wettability and readily provide high adhesive strength to various materials. Preferably, the hydroxyl group-containing compound (A1) is at least one polyol selected from polyolefin polyols, polydiene polyols, castor oil polyols, and polyester polyols.

[0011] As the hydroxyl group-containing compound (A1), the polyolefin-based polyol has a CC double bond. Examples of the polyolefin-based polyol are polybutadiene polyol (polydiene-based polyol) and polyisoprene polyol. As the hydroxyl group-containing compound (A1), the castor oil-based polyol has an ester bond. Examples of castor oil-based polyols are ricinoleic acid triglyceride, castor oil, refined castor oil, partially dehydrated castor oil, partially acylated castor oil, polymerized castor oil, diglycerides of castor oil fatty acids, and reaction products of castor oil or castor oil fatty acids with other polyols.

[0012] As the hydroxyl group-containing compound (A1), the polyester polyol may be obtained, for example, by the reaction of a polybasic acid or acid anhydride with a polyhydric alcohol, or by a ring-opening polymerization reaction. The polybasic acid is, for example, a polyhydric carboxylic acid. The polyol obtained by the ring-opening polymerization reaction is, for example, polycaprolactone diol or poly-3-methylvalerolactone diol.

[0013] The polycarboxylic acid is, for example, an aromatic carboxylic acid such as phthalic acid, isophthalic acid, or terephthalic acid, or an aliphatic carboxylic acid such as succinic acid, adipic acid, sebacic acid, maleic acid, fumaric acid, or itaconic acid. The acid anhydride is, for example, phthalic anhydride, trimellitic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride. The polycarboxylic acid and the acid anhydride can be used individually or in combination of two or more.

[0014] The polyhydric alcohols mentioned above are, for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylenediol, neopentyl glycol, tetraethylene glycol, tripropylene glycol, tetramethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,3-butylenediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, and hydrogenated bisphenol A. Alternatively, the polyhydric alcohols may be trihydric alcohols such as ricerin, trimethylolethane, and trimethylolpropane, or tetrahydric or higher alcohols such as pentaerythritol and dipentaerythritol. These polyhydric alcohols can be used individually or in combination of two or more.

[0015] For example, the hydroxyl group-containing compound (A1) is selected from the group consisting of polyolefin polyols, polydiene polyols, castor oil polyols, and polyester polyols, one or more of these.

[0016] The aromatic isocyanate (A2) is preferably a diisocyanate selected from at least one isocyanate selected from m-xylylene diisocyanate (m-XDI), p-xylylene diisocyanate (p-XDI), 2,4-tollylene diisocyanate, 2,6-tollylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 2,2'-diphenylmethane diisocyanate, as well as oligomers and mixtures of the aforementioned isocyanates. The oligomers include crude MDI. Among these, it is preferable to include 4,4'-diphenylmethane diisocyanate (MDI) because it can improve the wettability and adhesive strength of the adhesive. 4,4'-diphenylmethane diisocyanate is sold by Tosoh Corporation, for example, as Myrionate MT, MT-F, MTNBP, NM, etc.

[0017] In the present invention, the NCO% of urethane prepolymer A is preferably 3.5% or more and 15% or less. The higher the NCO%, the more it acts as a crosslinking agent.

[0018] The one-component moisture-curing adhesive according to the embodiment of the present invention preferably further contains a urethane prepolymer B having a peak in weight-average molecular weight within the range of 20,000 to 70,000. The peak refers to the weight-average molecular weight corresponding to the peak in the chromatogram in the GPC measurement. If multiple peaks are present in the measurement result, the highest peak is within the range. It is preferable that the peak is within the range, as this allows for sufficient tackiness of the one-component moisture-curing adhesive. The peak range is more preferably within the range of 25,000 to 60,000, and even more preferably within the range of 30,000 to 50,000.

[0019] When the one-component moisture-curing adhesive of the present invention contains the urethane prepolymer B, the mixing ratio of urethane prepolymer A to urethane prepolymer B is preferably in the range of 1:7 to 12:1 in terms of non-volatile content by weight. Compared to cases outside the above mixing ratio, it has been found that a mixing ratio within the above range provides a good balance between the relatively low molecular weight urethane prepolymer A, which acts as a crosslinking agent, and the relatively high molecular weight urethane prepolymer B. This results in a good balance of cohesive force and wettability, a synergistic effect from the blending of prepolymers, and is preferable in terms of adhesive strength. The above mixing ratio is more preferably in the range of 1:5 to 10:1, and even more preferably in the range of 1:4 to 9:1.

[0020] The urethane prepolymer B is preferably a urethane prepolymer obtained by reacting a polyol containing polypropylene glycol with an isocyanate prepolymer. The polypropylene glycol contained in the polyol preferably has a number average molecular weight in the range of 1,000 or more and 5,000 or less. When the number average molecular weight of the polypropylene glycol is within the above range, it is easy for the one-component moisture-curing adhesive to have appropriate adhesive strength, and it is easy to obtain good adhesive strength, which is preferable.

[0021] Furthermore, the number average molecular weight of the polyol constituting the urethane prepolymer B is more preferably in the range of 1,000 or more and 4,000 or less, and even more preferably in the range of 1,000 or more and 3,000 or less.

[0022] Note that the polyol may contain a polyol other than polypropylene glycol. For example, it may contain any one or a plurality of the polyols that can be used as the hydroxyl group-containing compound (A1). Further, the polyol may contain a polyether polyol other than polypropylene glycol. Furthermore, the polyol may contain the polyhydric alcohol exemplified in the description of the hydroxyl group-containing compound (A1).

[0023] The polyether polyol is preferably a diol, triol or tetrol. The polyether polyol may be a mixture of a plurality of diols, triols, and tetrols. Examples of the polyether polyol include polyoxyethylene, polyoxybutylene, polytetramethylene ether diol and triol.

[0024] And the isocyanate prepolymer that reacts with the polyol is preferably at least one selected from 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 2,2'-diphenylmethane diisocyanate. When these isocyanate prepolymers are used, appropriate cohesive force is easily obtained, so the adhesive strength is easily achieved.

[0025] The one-component moisture-curing adhesive of the present invention may be added with an organic solvent as necessary. The organic solvent is preferably a solvent other than alcohol, and any solvent that can dissolve the urethane prepolymer may be used. The organic solvent is, for example, dimethyl carbonate, isohexane, carboxylic acid ester, acetone, or a mixture thereof. The carboxylic acid ester is, for example, methyl acetate and ethyl acetate.

[0026] The one-component moisture-curing adhesive of the present invention preferably has a viscosity (25°C, 20 rpm) of 5,000 to 300,000, and more preferably within the range of 10,000 mPa·s or more and 30,000 mPa·s or less.

[0027] The one-component moisture-curing adhesive of the present invention may contain a filler, a curing catalyst, a diluent, a stabilizer, a pigment, an antioxidant, a dehydrating agent, and other additives as long as the gist of the present invention is not impaired.

[0028] Examples of the filler include calcium carbonate, carbon black, clay, talc, mica, titanium oxide, zeolite, diatomaceous earth, and silica. Other types of fillers may be used, and there is no particular limitation. Further, the fillers can be used alone or in combination. For example, as calcium carbonate, heavy calcium carbonate and surface-treated calcium carbonate can be used. Silica and surface-treated calcium carbonate can be used as thixotropic agents.

[0029] For example, metal-based catalysts and amine-based catalysts can be used as curing catalysts. Examples of metal-based catalysts include dibutyltine dilaurate, cobalt naphthenate, stannous chloride, and tetra-n-butyltine. Examples of amine-based catalysts include triethylamine, triethylenediamine, morpholino ether-based, imidazole-based, and DBU salt-based catalysts. One or a mixture of any of these curing catalysts can be used. In the one-component moisture-curing adhesive of the present invention, it is preferable that the curing catalyst occupies a range of 0.1% by mass or more and less than 2.0% by mass of the total amount. If the amount of catalyst is too little, curing will be weak. If the amount of catalyst is too much, storage stability will be impaired. This range of catalyst addition is particularly effective as it does not cause problems in terms of both curing and storage stability.

[0030] Other additives that can be used include, for example, silane coupling agents, titanate coupling agents, surface modifiers, UV absorbers, antioxidants, drying agents, and tackifiers. Only one of the above-mentioned additives may be added, or multiple additives may be added.

[0031] A one-component moisture-curing adhesive may be manufactured using known methods. The manufacturing method is not particularly limited, as long as the manufactured one-component moisture-curing adhesive does not impair the purpose of the present invention. For example, the following method can be used: A hydroxyl group-containing compound (A1) is placed in a reaction vessel together with a solvent as needed, and the contents are heated and thoroughly stirred. After uniform dissolution, an aromatic isocyanate (A2) is added to the contents and reacted to obtain urethane prepolymer A. At this time, the temperature maintained during the reaction is, for example, any temperature within the range of 60°C to 100°C. The maintenance temperature can be set according to the raw materials and composition. The reaction time is about 2 to 24 hours. Urethane prepolymer B can also be manufactured in the same manner as urethane prepolymer A. Subsequently, urethane prepolymer A and urethane prepolymer B are mixed. Fillers, curing catalysts, diluents, stabilizers, pigments, antioxidants, dehydrating agents, and other additives are added to the mixture as needed. By stirring until uniform, the one-component moisture-curing adhesive of the present invention is obtained.

[0032] The one-component moisture-curing adhesive of the present invention is suitable for bonding various substrates. For example, it is suitable for bonding polyvinyl chloride, rubber, and olefin substrates. It is particularly suitable for on-site installation (adhesive application) of flooring materials. It can be used for flooring materials in any shape, such as tiles, sheets, or long sheets. The flooring material is, for example, made of resin. The material of the flooring material is, for example, polyvinyl chloride resin, polyolefin resin such as polypropylene and polystyrene, polyurethane resin, synthetic rubber such as styrene-butadiene rubber, polyester resin such as polybutylene terephthalate, or natural rubber. The one-component moisture-curing adhesive of the present invention can also be used for bonding materials other than flooring materials. For example, it can be used for bonding to building substrates. Specifically, it can be suitably applied to bonding building substrates made of mortar, concrete, fiber-reinforced cement board, or plywood to substrates. Of these substrates, it is particularly suitable for bonding to polyvinyl chloride resin. Since it has good adhesive strength regardless of the substrate, it can also be used for bonding materials other than flooring and substrates. [Examples]

[0033] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to these.

[0034] [Example 1] 1. Preparation of a one-component moisture-curing adhesive (1) Urethane prepolymer A As shown in Table 1, the hydroxyl group-containing compound (A1) is hydroxyl-terminated liquid polybutadiene (Mn: 2,800) (R-45HT, manufactured by Idemitsu Kosan Co., Ltd.), a polydiene polyol having a CC double bond. The aromatic isocyanate (A2) is myrionate MT (4,4'-diphenylmethane diisocyanate) (MDI), manufactured by Tosoh Corporation. The solvent is DMC (dimethyl carbonate). The hydroxyl group-containing compound (A1), aromatic isocyanate (A2), and solvent are added to the reaction vessel so that the R value (moles of isocyanate groups / moles of hydroxyl groups) is 3.0 and the non-volatile content is 75.0%. In this example, 2,800 parts by mass of R-45HT, 825 parts by mass of myrionate MT, and 1,208 parts of solvent are added to the reaction vessel. The contents were heated and thoroughly stirred while being reacted at a temperature of approximately 80°C. As a result, urethane prepolymer A was obtained. The number-average molecular weight of the obtained urethane prepolymer A was 3,350. The NCO% was 3.96%.

[0035] (2) Urethane prepolymer B The polyol is polypropylene glycol (PPG) with a number-average molecular weight of 2,000 and 2 hydroxyl groups. The isocyanate is myrionate MT as described above. The solvent is DMC (dimethyl carbonate). The polyol, isocyanate, and solvent are added to the reaction vessel so that the R value is 1.2 and the non-volatile content is 60.0%. In this example, 2,000 parts by mass of PPG, 300 parts by mass of myrionate MT, and 1,533 parts by mass of solvent are added to the reaction vessel. The contents are heated and thoroughly stirred while being reacted at a temperature of approximately 80°C. As a result, urethane prepolymer B is obtained. The peak weight-average molecular weight of the obtained urethane prepolymer B was 37,000. The NCO% of urethane prepolymer B was 0.74%.

[0036] (3) One-component moisture-curing adhesive An adhesive was prepared using the urethane prepolymer A and urethane prepolymer B obtained above. 90 parts by mass (67.5 parts by mass non-volatile content) of urethane prepolymer A, 30 parts by mass (18.0 parts by mass non-volatile content) of urethane prepolymer B, and furthermore, 1.30 parts by mass of p-toluenesulfonyl isocyanate (PTSI) as a stabilizer, and 3.5 parts by mass of hydrophobic fumed silica (Cab-O-Sil TS-720, manufactured by Cabot Corporation) and 115.0 parts by mass of heavy calcium carbonate (Whiteon P-30, manufactured by Toyo Fine Chemical Co., Ltd.) as fillers were added to a container. After thorough stirring, the one-component moisture-curing adhesive of this example was obtained. In this example, 40 parts by mass of dimethyl carbonate (DMC) was added to the container as a solvent as appropriate. A one-component moisture-curing adhesive with a viscosity of 25,600 mPa·s (25℃, 20 rpm) was obtained.

[0037] 2. Evaluation (1) Evaluation of uniaxial tensile adhesive strength (normal conditions) The adhesive strength was evaluated according to JIS A 5536:2015 "Adhesives for Floor Finishing Materials" 6.3.2d)1) normal tensile strength. Three types of flooring materials were used for testing: multi-layer floor sheet (PVC), single-layer floor sheet (rubber), and multi-layer floor tile (olefin). For the multi-layer floor sheet (PVC), MS Fresh (made of PVC) from TOLI Corporation was used. For the single-layer floor sheet (rubber), Astroface (made of rubber) from Nichiman Rubbertech Co., Ltd. was used. For the multi-layer floor tile (olefin), Stratica (made of olefin) from Amtico Corporation was used. The acceptable value for urethane resin adhesives in this evaluation was 0.8 N / mm². 2 That's all.

[0038] (2) Evaluation of uniaxial tensile adhesive strength (water resistance) The adhesive strength was evaluated according to JIS A 5536:2015 "Adhesives for Floor Finishing Materials" 6.3.2d)3) Immersion tensile strength. Three types of floor materials were used as test materials: multi-layer floor sheet (PVC), single-layer floor sheet (rubber), and multi-layer floor tile (olefin). These test floor materials were the same as for (1) uniaxial tensile strength (normal conditions): MS Fresh (PVC), Astroface (rubber), and Stratica (olefin). The acceptable value for urethane resin adhesives in this evaluation was 0.5 N / mm². 2 That's all.

[0039] (3) Evaluation of 90-degree peel adhesion strength (normal conditions) The adhesive strength was evaluated according to JIS A 5536:2015 "Adhesives for Floor Finishing Materials" 6.3.3e)1) normal peel adhesion strength. Two types of flooring materials were used for testing: multi-layer floor sheet (PVC) and single-layer floor sheet (rubber). For the multi-layer floor sheet (PVC), Toughslip (made of PVC) from Takiron CI Co., Ltd. was used. For the single-layer floor sheet (rubber), two types of Astroface (made of rubber) from Nichiman Rubbertech Co., Ltd. were used. The acceptable value for urethane resin adhesives in this evaluation is 20 N / 25 mm or higher.

[0040] (4) Evaluation of 90-degree peel bond strength (water resistance) The adhesive strength was evaluated according to JIS A 5536:2015 "Adhesives for Floor Finishing Materials" 6.3.3e)2) Submerged peel adhesion strength. Two types of flooring materials were used as test materials: multi-layer floor sheet (PVC) and single-layer floor sheet (rubber). These test flooring materials were the same as for (3) 90-degree peel adhesion strength (normal conditions), consisting of Toughslip (PVC) and Astroface (rubber). The acceptable value for urethane resin adhesives in this evaluation is 10 N / 25 mm or higher.

[0041] The evaluation results are shown in Table 1. In this embodiment, the one-component moisture-curing adhesive met the acceptable values ​​in all cases except when a single-layer floor sheet (rubber) was used as the test flooring material, in terms of (3) 90-degree peel adhesion strength (normal conditions).

[0042] (5) Overall Judgment For each of the test floor materials described in (1) to (4) above, a rating of "G" was given if 0 or 1 item failed to meet the conformity value, and "NG" was given if 2 or more items failed to meet the conformity value. The results are shown in Table 1. The result for this example is "G".

[0043] [Example 2] As shown in Table 1, the hydroxyl group-containing compound (A1) is a polydiene polyol, specifically hydroxyl-terminated liquid polybutadiene (Mn: 1,200) (R-15HT, manufactured by Idemitsu Kosan Co., Ltd.). The aromatic isocyanate (A2) and solvent are the same as in Example 1. The hydroxyl group-containing compound (A1), aromatic isocyanate (A2), and solvent are added to the reaction vessel so that the R value is 3.0 and the non-volatile content is 75.0%. In this example, 1,200 parts by mass of R-15HT, 825 parts by mass of myrionate MT, and 675 parts of solvent are added to the reaction vessel. These are reacted in the same manner as in Example 1. As a result, the urethane prepolymer A of this example was obtained. The number-average molecular weight of the obtained urethane prepolymer A was 1750. The NCO% of urethane prepolymer A was 6.80%. A one-component moisture-curing adhesive of this example was obtained in the same manner as in Example 1, except that 90 parts by mass (67.5 parts by mass of non-volatile content) of the obtained urethane prepolymer A were used and 30 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0044] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesives. All of the one-component moisture-curing adhesives in this example met the requirements. The overall rating was "G".

[0045] [Example 3] As shown in Table 1, the hydroxyl group-containing compound (A1) is a trifunctional polyester polyol (polyol with ester bonds) (Mn: 1,000) (Kuraray Polyol F1010, manufactured by Kuraray Co., Ltd.). The aromatic isocyanate (A2) and solvent are the same as in Example 1. The hydroxyl group-containing compound (A1), aromatic isocyanate (A2), and solvent are added to the reaction vessel so that the R value is 3.0 and the non-volatile content is 75.0%. In this example, 1,000 parts by mass of F1010, 1,125 parts by mass of myrionate MT, and 708.3 parts of solvent are added to the reaction vessel. These are reacted in the same manner as in Example 1. As a result, the urethane prepolymer A of this example was obtained. The number-average molecular weight of the obtained urethane prepolymer A was 1750. The NCO% of urethane prepolymer A was 8.90%. The one-component moisture-curing adhesive of this example was obtained in the same manner as in Example 1, except that 90 parts by mass (67.5 parts by mass of non-volatile content) of the obtained urethane prepolymer A were used and 20 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0046] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesive. In this example, the one-component moisture-curing adhesive met the acceptable values ​​in all cases except when a single-layer floor sheet (rubber) was used as the test flooring material, in terms of (3) 90-degree peel adhesion strength (normal conditions). The overall rating was "G".

[0047] [Example 4] As shown in Table 1, the hydroxyl group-containing compound (A1) is refined castor oil (Mn: approximately 950) (LAV, manufactured by Ito Oil Co., Ltd.). The aromatic isocyanate (A2) and solvent are the same as in Example 1. The hydroxyl group-containing compound (A1), aromatic isocyanate (A2), and solvent are added to the reaction vessel so that the R value is 3.0 and the non-volatile content is 75.0%. In this example, 950 parts by mass of LAV, 1,012.5 parts by mass of myrionate MT, and 654.2 parts of solvent are added to the reaction vessel. These are reacted in the same manner as in Example 1. As a result, the urethane prepolymer A of this example was obtained. The number-average molecular weight of the obtained urethane prepolymer A was 1,625. The NCO% of urethane prepolymer A was 8.67%. The one-component moisture-curing adhesive of this example was obtained in the same manner as in Example 1, except that 105 parts by mass (78.75 parts by mass of non-volatile content) of the obtained urethane prepolymer A and 15 parts by mass (9.0 parts by mass of non-volatile content) of the same urethane prepolymer B as in Example 1 were used, and 45 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0048] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesive. In this example, the one-component moisture-curing adhesive met the acceptable values ​​in all cases except when a single-layer floor sheet (rubber) was used as the test flooring material, in terms of (3) 90-degree peel adhesion strength (normal conditions). The overall rating was "G".

[0049] [Comparative Example 1] A one-component moisture-curing adhesive for this comparative example was obtained in the same manner as in Example 1, except that 120 parts by mass (72.0 parts by mass of non-volatile content) of urethane prepolymer B, the same as in Example 1, was used instead of urethane prepolymer A, and 36 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0050] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesive. In this comparative example, the one-component moisture-curing adhesive did not meet the acceptable value in (3) 90-degree peel adhesion strength (normal conditions), except when a multi-layer floor sheet (PVC) was used as the test flooring material. The overall judgment was "NG".

[0051] [Example 5] As shown in Table 1, urethane prepolymer A of this example was obtained in the same manner as in Example 4. The R value, non-volatile content, number-average molecular weight, and NCO% were the same as in Example 4. The one-component moisture-curing adhesive of this example was obtained in the same manner as in Example 1, except that 20 parts by mass (15.0 parts by mass non-volatile content) of the obtained urethane prepolymer A and 100 parts by mass (60.0 parts by mass non-volatile content) of the same urethane prepolymer B as in Example 1 were used, and 38 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0052] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesive. In this example, the one-component moisture-curing adhesive met the acceptable values ​​in all cases except when a single-layer floor sheet (rubber) was used as the test flooring material, in terms of (3) 90-degree peel adhesion strength (normal conditions). The overall rating was "G".

[0053] [Example 6] As shown in Table 1, urethane prepolymer A of this example was obtained in the same manner as in Example 4. The R value, non-volatile content, number-average molecular weight, and NCO% were the same as in Example 4. The one-component moisture-curing adhesive of this example was obtained in the same manner as in Example 1, except that 30 parts by mass (non-volatile content 22.5 parts by mass) of the obtained urethane prepolymer A and 90 parts by mass (non-volatile content 54.0 parts by mass) of the same urethane prepolymer B as in Example 1 were used, and 28 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0054] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesives. All of the one-component moisture-curing adhesives in this example met the requirements. The overall rating was "G".

[0055] [Example 7] As shown in Table 1, urethane prepolymer A of this example was obtained in the same manner as in Example 4. The R value, non-volatile content, number-average molecular weight, and NCO% were the same as in Example 4. The one-component moisture-curing adhesive of this example was obtained in the same manner as in Example 1, except that 60 parts by mass (45.0 parts by mass non-volatile content) of the obtained urethane prepolymer A and 60 parts by mass (36.0 parts by mass non-volatile content) of the same urethane prepolymer B as in Example 1 were used, and 15 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0056] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesives. In this example, all of the one-component moisture-curing adhesives met the required standards. The overall rating was "G".

[0057] [Example 8] As shown in Table 1, urethane prepolymer A of this example was obtained in the same manner as in Example 4. The R value, non-volatile content, number-average molecular weight, and NCO% were the same as in Example 4. The one-component moisture-curing adhesive of this example was obtained in the same manner as in Example 1, except that 90 parts by mass (67.5 parts by mass non-volatile content) of the obtained urethane prepolymer A and 30 parts by mass (18.0 parts by mass non-volatile content) of the same urethane prepolymer B as in Example 1 were used, and 12 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0058] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesives. In this example, all of the one-component moisture-curing adhesives met the required standards. The overall rating was "G".

[0059] [Example 9] As shown in Table 1, urethane prepolymer A of this example was obtained in the same manner as in Example 4. The R value, non-volatile content, number-average molecular weight, and NCO% were the same as in Example 4. The one-component moisture-curing adhesive of this example was obtained in the same manner as in Example 1, except that 120 parts by mass (90.0 parts by mass of non-volatile content) of the obtained urethane prepolymer A was used, urethane prepolymer B was not used, and 9 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0060] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesive. In this example, the one-component moisture-curing adhesive met the acceptable values ​​in all cases except when a single-layer floor sheet (rubber) was used as the test flooring material, in terms of (3) 90-degree peel adhesion strength (normal conditions). The overall rating was "G".

[0061] [Example 10] As shown in Table 1, the hydroxyl group-containing compound (A1) is refined castor oil (Mn: approximately 950) (LAV, manufactured by Ito Oil Co., Ltd.). The aromatic isocyanate (A2) is Cosmonate T-80 (manufactured by Mitsui Chemicals, Inc., a mixture of approximately 80% 2,4-tolylenediisocyanate and approximately 20% 2,6-tolylenediisocyanate) (TDI). The solvent is the same as in Example 1. The hydroxyl group-containing compound (A1), aromatic isocyanate (A2), and solvent are added to the reaction vessel so that the R value is 3.0 and the non-volatile content is 75.0%. In this example, 950 parts by mass of LAV, 704.7 parts by mass of Cosmonate T-80, and 551.6 parts of solvent are added to the reaction vessel. These are reacted in the same manner as in Example 1. As a result, urethane prepolymer A is obtained. The number average molecular weight of the obtained urethane prepolymer A was 1,420. Furthermore, the NCO% of urethane prepolymer A was 10.29%. The one-component moisture-curing adhesive of this example was obtained in the same manner as in Example 1, except that 90 parts by mass (67.5 parts by mass of non-volatile content) of the obtained urethane prepolymer A were used and 20 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0062] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesive. In this example, the one-component moisture-curing adhesive met the acceptable values ​​in all cases except when a single-layer floor sheet (rubber) was used as the test flooring material for (3) 90-degree peel adhesion strength (normal conditions). The overall rating was "G".

[0063] [Comparative Example 2] As shown in Table 1, the hydroxyl group-containing compound is a polyether polyol with an average of 3 hydroxyl groups (Mn: 1,000, Actcol T1000, manufactured by Mitsui Chemicals, Inc.). The aromatic isocyanate is myrionate MT. The solvent is DMC. The hydroxyl group-containing compound (A1), aromatic isocyanate (A2), and solvent are added to the reaction vessel so that the R value is 3.0 and the non-volatile content is 75.0%. In this example, 1,000 parts by mass of Actcol T1000, 1,125 parts by mass of myrionate MT, and 708.3 parts of solvent are added to the reaction vessel. The contents are heated and thoroughly stirred while being reacted at a temperature of approximately 80°C. As a result, a urethane prepolymer was obtained. The number-average molecular weight of the obtained urethane prepolymer was 1,750. The non-volatile content was 75.0%. Furthermore, the NCO% of the urethane prepolymer was 8.90%. A one-component moisture-curing adhesive for this comparative example was obtained in the same manner as in Example 1, except that 120 parts by mass (90.0 parts by mass of non-volatile content) of the obtained urethane prepolymer was used instead of urethane prepolymer A, urethane prepolymer B was not used, and 15 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0064] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesive. In this comparative example, the one-component moisture-curing adhesive did not meet the acceptable value for (3) 90-degree peel adhesion strength (normal conditions) when multi-layer floor sheet (PVC) and single-layer floor sheet (rubber) were used as test floor materials, and the overall judgment was "NG".

[0065] [Comparative Example 3] A urethane prepolymer was obtained in the same manner as in Comparative Example 2. The R value, number average molecular weight, non-volatile content, and NCO% of the obtained urethane prepolymer were the same as in Comparative Example 2. A one-component moisture-curing adhesive of this comparative example was obtained in the same manner as in Example 1, except that 90 parts by mass (67.5 parts by mass of non-volatile content) of the obtained urethane prepolymer was used and 30 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0066] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesive. In this comparative example, the one-component moisture-curing adhesive failed to meet the required values ​​in (2) uniaxial tensile adhesive strength (water resistance) when multi-layer floor tiles (olefin) were used as the test flooring material, and in (3) 90-degree peel adhesive strength (normal conditions) when single-layer floor sheets (rubber) were used as the test flooring material. The overall judgment was "NG".

[0067] [Comparative Example 4] As shown in Table 1, the hydroxyl group-containing compound (A1) is refined castor oil (Mn: approximately 950) (LAV, manufactured by Ito Oil Co., Ltd.). The isocyanate is hydrogenated MDI (H12MDI, manufactured by Manka Chemical Industry Co., Ltd.). The solvent is the same as in Example 1. The hydroxyl group-containing compound (A1), aromatic isocyanate (A2), and solvent are added to the reaction vessel so that the R value is 3.0 and the non-volatile content is 75.0%. In this comparative example, 950 parts by mass of LAV, 1061 parts by mass of H12MDI, and 670.4 parts of solvent are added to the reaction vessel. The contents are heated and thoroughly stirred while being reacted at a temperature of approximately 80°C. As a result, a urethane prepolymer was obtained. The number-average molecular weight of the obtained urethane prepolymer was 1,657. The (NCO / OH) value of the obtained urethane prepolymer was 8.45%. A one-component moisture-curing adhesive for this comparative example was obtained in the same manner as in Example 1, except that 90 parts by mass (67.5 parts by mass of non-volatile content) of the obtained urethane prepolymer was used instead of urethane prepolymer A, 0.10 parts by mass of dioctyl tin laurate-based catalyst (STX-12L, manufactured by Daikyo Chemical Industries, Ltd.) was added, and 20 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0068] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesive. The one-component moisture-curing adhesive used in this comparative example failed to meet the required values ​​in the following cases: (1) when using multi-layer floor sheets (PVC), single-layer floor sheets (rubber), and multi-layer floor tiles (olefin) as test flooring materials for uniaxial tensile adhesive strength (normal conditions); (2) when using multi-layer floor tiles (olefin) as test flooring materials for uniaxial tensile adhesive strength (water-resistant); (3) when using multi-layer floor sheets (PVC) and single-layer floor sheets (rubber) as test flooring materials for 90-degree peel adhesive strength (normal conditions); and (4) when using single-layer floor sheets (rubber) as test flooring materials for 90-degree peel adhesive strength (water-resistant). The overall judgment was "NG".

[0069] [Comparative Example 5] As shown in Table 1, the hydroxyl group-containing compound (A1) is refined castor oil (Mn: approximately 950) (LAV, manufactured by Ito Oil Co., Ltd.). The isocyanate is isophorone diisocyanate (IPDI, manufactured by Covest Corporation), which is an alicyclic isocyanate. The solvent is the same as in Example 1. The hydroxyl group-containing compound (A1), aromatic isocyanate (A2), and solvent are added to the reaction vessel so that the R value is 3.0 and the non-volatile content is 75.0%. In this comparative example, 950 parts by mass of LAV, 899 parts by mass of IPDI, and 616.4 parts of solvent are added to the reaction vessel. The contents are heated and thoroughly stirred while being reacted at a temperature of approximately 80°C. As a result, a urethane prepolymer was obtained. The number-average molecular weight of the obtained urethane prepolymer was 1,549. A one-component moisture-curing adhesive for this comparative example was obtained in the same manner as in Example 1, except that 90 parts by mass (67.5 parts by mass of non-volatile content) of the obtained urethane prepolymer was used instead of urethane prepolymer A, 0.10 parts by mass of dioctyl tin laurate-based catalyst (STX-12L, manufactured by Daikyo Chemical Industries, Ltd.) was added, and 20 parts by mass of dimethyl carbonate (DMC) was used as the solvent.

[0070] Table 1 shows the evaluation results of the obtained one-component moisture-curing adhesive. The one-component moisture-curing adhesive used in this comparative example failed to meet the required values ​​in the following cases: (1) uniaxial tensile adhesive strength (normal conditions) when multi-layer floor sheet (PVC), single-layer floor sheet (rubber), and multi-layer floor tile (olefin) were used as test floor materials; (3) 90-degree peel adhesive strength (normal conditions) when multi-layer floor sheet (PVC) and single-layer floor sheet (rubber) were used as test floor materials; and (4) 90-degree peel adhesive strength (water resistance) when single-layer floor sheet (rubber) was used as test floor material. The overall judgment was "NG".

[0071] [Table 1]

[0072] As described above, the present invention provides a one-component moisture-curing adhesive that has good adhesive strength regardless of the adherend.

Claims

1. A one-component moisture-curing adhesive containing urethane prepolymer A, The urethane prepolymer A is a urethane prepolymer obtained by reacting a hydroxyl group-containing compound (A1) with an aromatic isocyanate (A2). The hydroxyl group-containing compound (A1) is a polyol having at least one of an ester bond and a C-C double bond. A one-component moisture-curing adhesive wherein the number average molecular weight of the urethane prepolymer A is in the range of 1,000 to 4,000.

2. Furthermore, the one-component moisture-curing adhesive according to claim 1, comprising a urethane prepolymer B having a peak weight-average molecular weight in the range of 20,000 to 70,000.

3. The one-component moisture-curing adhesive according to claim 1 or 2, wherein the hydroxyl group-containing compound (A1) is at least one polyol selected from polyolefin-based polyols, polydiene-based polyols, castor oil-based polyols, and polyester-based polyols.

4. The one-component moisture-curing adhesive according to claim 1 or 2, wherein the aromatic isocyanate (A2) is at least one isocyanate selected from m-xylylene diisocyanate, p-xylylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 2,2'-diphenylmethane diisocyanate, as well as a diisocyanate selected from oligomers and mixtures of the aforementioned isocyanates.

5. The urethane prepolymer B is a urethane prepolymer obtained by reacting a polyol containing polypropylene glycol with an isocyanate prepolymer. The polyol contains polypropylene glycol having a number average molecular weight in the range of 1,000 to 5,000. The one-component moisture-curing adhesive according to claim 2, wherein the isocyanate prepolymer is at least one selected from 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 2,2'-diphenylmethane diisocyanate.

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