Moisture-curable hot melt adhesive composition

Abstract

Provided is a new moisture-curable hot-melt adhesive composition having an even better effect. An embodiment of the present invention is a moisture-curable hot-melt adhesive composition including a urethane prepolymer, characterized in that the urethane prepolymer is one obtained by reacting a polyol compound with a polyisocyanate compound and has a urethane bond content of 0.90 mol / kg or higher.

Description

[Technical Field]

[0001] The present invention relates to a moisture-curable hot melt adhesive composition. [Background technology]

[0002] Moisture-curing hot melt adhesives, which cure in response to moisture, can be applied to an adherend, pressed against another adherend, and then cooled and solidified, allowing the adhesive to bond. This makes them highly workable. For this reason, moisture-curing hot melt adhesives are used in a variety of fields, including construction, electrical engineering, and automotive. Moisture-curing hot melt adhesives generally contain crystalline ester polyols to achieve high initial peel strength (peel strength immediately after bonding). Ester polyols undergo hydrolysis in humid and hot environments, which can lead to unstable adhesion after bonding.

[0003] Patent Document 1 discloses a moisture-curable polyurethane hot-melt resin composition that contains a polycarbonate polyol made from a glycol compound having a branched structure, and that has excellent initial adhesive strength, final adhesive strength, and hydrolysis resistance.

[0004] Patent Document 2 discloses an adhesive composition having improved green strength and hydrolysis resistance, which contains an effective amount of one or more non-polymer diols selected from aromatic diols, aliphatic diols, and mixtures thereof, and optionally a functional and / or non-functional polymer (acrylic) or a mixture thereof. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-097651 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-110788 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the moisture-curable polyurethane hot-melt resin composition of Patent Document 1 has a high viscosity, which may limit the type of coating machine that can be used for coating. Also, the adhesive composition of Patent Document 2 contains an acrylic polymer, which requires coating at a higher temperature, which may cause the adhesive composition to gel.

[0007] Therefore, an object of the present invention is to provide a new moisture-curable hot melt adhesive composition that has superior effects. [Means for solving the problem]

[0008] The present inventors have conducted extensive research and found that a moisture-curable hot melt adhesive composition containing a specific urethane prepolymer can solve the above problems, and have completed the present invention.

[0009] The embodiment (1) of the present invention is A moisture-curable hot melt adhesive composition comprising a urethane prepolymer, The urethane prepolymer is obtained by reacting a polyol compound with a polyisocyanate compound, The moisture-curable hot melt adhesive composition is characterized in that the urethane bond amount of the urethane prepolymer is 0.90 mol / kg or more. The second aspect of the present invention is The moisture-curable hot melt adhesive composition of the above form (1) is characterized by further containing a carbodiimide compound. The third aspect of the present invention is In the moisture-curable hot melt adhesive composition of the above aspect (2), the molecular weight or number average molecular weight of the carbodiimide compound is 500 or more. The fourth aspect of the present invention is In the moisture-curable hot melt adhesive composition of any one of the above forms (1) to (3), the polyol compound includes a polyether polyol compound and a polyester polyol compound. The fifth aspect of the present invention is The moisture-curable hot melt adhesive composition of any one of the above forms (1) to (4) is characterized in that the ester bond amount of the urethane prepolymer is 6.00 mol / kg or less. Form (6) of the present invention is The moisture-curable hot melt adhesive composition of any one of the above forms (1) to (5) is for use in automobile interior materials. Form (7) of the present invention is The first substrate and the second substrate are laminated together via an adhesive layer, The adhesive layer is a cured product of the moisture-curable hot melt adhesive composition of any one of Forms (1) to (6), The first substrate and the second substrate are each independently selected from the group consisting of a foam, natural leather, synthetic leather, a film, a woven fabric, and a nonwoven fabric, making up a laminate. [Effects of the Invention]

[0010] According to the present invention, a new moisture-curable hot melt adhesive composition having superior effects can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0011] When the compounds described herein have isomers, all possible isomers can be used in the present invention unless otherwise specified.

[0012] In the present application, the number average molecular weight is measured by gel permeation chromatography. In the present application, when an upper limit value and a lower limit value are separately described, it is considered that a numerical range combining any upper limit value and any lower limit value is substantially disclosed. In this application, unless otherwise specified, various measurements are performed at room temperature (25°C).

[0013] 1. Moisture-curable hot melt adhesive composition The moisture-curable hot melt adhesive composition of the present disclosure includes a urethane prepolymer. The urethane prepolymer according to the present disclosure is obtained by reacting a polyol compound with a polyisocyanate compound. The urethane prepolymer preferably has a urethane bond content of 0.90 mol / kg or more, although the present disclosure is not limited thereto.

[0014] The moisture-curable hot melt adhesive composition may further contain a carbodiimide compound. The moisture-curable hot melt adhesive composition may also contain other additives, if necessary.

[0015] The moisture-curable hot melt adhesive composition of the present disclosure is described in detail below.

[0016] 1-1. Raw materials for moisture-curing hot melt adhesive compositions 1-1-1. Urethane prepolymer The urethane prepolymer according to the present disclosure can be obtained by reacting a polyol compound with a polyisocyanate compound. Hydroxyl groups contained in the polyol compound react with isocyanate groups contained in the polyisocyanate compound to form urethane bonds, thereby obtaining the urethane prepolymer. Furthermore, the urethane prepolymer can contain a catalyst as a raw material when reacting the polyol compound with the polyisocyanate compound.

[0017] Polyol compounds The polyol compound used as a raw material for the urethane prepolymer according to the present disclosure is not particularly limited as long as the effects of the present disclosure are not impaired, and examples thereof include polyether polyol compounds, polyester polyol compounds, polycarbonate polyol compounds, polyester ether polyol compounds, polyhydric phenol compounds, etc. These can be used alone or in combination.

[0018] Examples of polyether polyol compounds include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc., which are obtained by polymerizing cyclic ethers such as ethylene oxide, propylene oxide, tetrahydrofuran, etc., and copolyethers thereof. Polyether polyol compounds can also be obtained by polymerizing the above-mentioned cyclic ethers using polyhydric alcohols such as glycerin and trimethylolethane. Examples of polyester polyol compounds include polyols obtained by a dehydration condensation reaction between a polycarboxylic acid compound (e.g., a dicarboxylic acid) and a polyol compound (e.g., a diol). Examples of polycarboxylic acid compounds include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and alicyclic dicarboxylic acids such as hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid; or acid esters or acid anhydrides thereof. Examples of polyol compounds include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, and mixtures thereof. Examples of other polyester polyols include polylactone diols obtained by ring-opening polymerization of lactone monomers such as ε-caprolactone and methylvalerolactone. Examples of polycarbonate polyol compounds include those obtained by reacting at least one polyhydric alcohol such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, or diethylene glycol with diethylene carbonate, dimethyl carbonate, diethyl carbonate, or the like. Examples of polyester ether polyol compounds include polyols obtained by a dehydration condensation reaction between a polycarboxylic acid compound (e.g., a dicarboxylic acid) and a polyether polyol. Examples of polycarboxylic acid compounds include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; alicyclic dicarboxylic acids such as hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid; and acid esters or acid anhydrides thereof. Examples of polyether polyols include glycols such as diethylene glycol or propylene oxide adducts, or mixtures thereof. Examples of polyhydric phenol compounds include monocyclic polyhydric phenols such as pyrogallol and hydroquinone; bisphenols such as bisphenol A, bisphenol F, and bisphenol sulfone; and the like.

[0019] These polyol compounds can be used alone or in combination. In particular, polyether polyol compounds can improve the hydrolysis resistance of the cured product of the moisture-curable hot melt adhesive composition. Furthermore, polyester polyol compounds have the effect of improving the heat resistance of the cured product of the moisture-curable hot melt adhesive composition. Since these effects are simultaneously achieved, it is preferable that the polyol compound contains a polyether polyol compound and a polyester polyol compound.

[0020] The mixing ratio (mass ratio) of the polyether polyol compound and the polyester polyol compound is not particularly limited as long as it does not impair the effects of the present disclosure, and can be, for example, 20 / 80 to 80 / 20 (total mass of all polyether polyol compounds / total mass of all polyester polyol compounds), preferably 30 / 70 to 70 / 30, more preferably 40 / 60 to 60 / 40, and even more preferably 45 / 55 to 65 / 35. When the mixing ratio of the polyether polyol compound and the polyester polyol compound is within this range, the moisture-curable hot melt adhesive composition can have better aging resistance under humid heat. In the present disclosure, polyester ether polyol compounds are considered to be polyether polyol compounds.

[0021] The molecular weight or number average molecular weight of the polyol compound is not particularly limited as long as it does not impair the effects of the present disclosure, and can be freely selected in consideration of the physical properties of the urethane prepolymer. The molecular weight or number average molecular weight of the polyol compound can be, for example, 300 to 8,000.

[0022] The hydroxyl value of the polyol compound is not particularly limited as long as the effects of the present disclosure are not impaired, and can be freely selected in consideration of the physical properties of the urethane prepolymer. The hydroxyl value of the polyol compound can be, for example, 50 to 1,000 mg KOH / g. Here, the hydroxyl value is a value measured in accordance with JIS K0070:1992 "Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value, and unsaponifiable matter of chemical products."

[0023] Polyisocyanate compounds The polyisocyanate compound that is the raw material for the urethane prepolymer according to the present disclosure is not particularly limited as long as the effects of the present disclosure are not impaired. The polyisocyanate compound may be a difunctional polyisocyanate compound or a tri- or higher functional polyisocyanate compound. The polyisocyanate compound may be any of aromatic, aliphatic and alicyclic compounds. For example, bifunctional polyisocyanate compounds include: Aromatic polyisocyanate compounds include 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), and 2,2'-diphenylmethane diisocyanate. (2,2'-MDI), hydrogenated MDI, xylylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, polymethylene polyphenyl polyisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, tetramethylxylene diisocyanate (TMXDI), etc.; Alicyclic polyisocyanate compounds include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, and methylcyclohexane diisocyanate; Alkylene-based polyisocyanate compounds include butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, and lysine diisocyanate; Examples include: Examples of tri- or higher functional polyisocyanate compounds include isocyanate compounds such as 1-methylbenzene-2,4,6-triisocyanate, 1,3,5-trimethylbenzene-2,4,6-triisocyanate, biphenyl-2,4,4'-triisocyanate, diphenylmethane-2,4,4'-triisocyanate, methyldiphenylmethane-4,6,4'-triisocyanate, 4,4'-dimethyldiphenylmethane-2,2',5,5'tetraisocyanate, triphenylmethane-4,4',4"-triisocyanate, polymeric MDI, lysine ester triisocyanate, 1,3,6-hexamethylene triisocyanate, 1,6,11-undecane triisocyanate, bicycloheptane triisocyanate, and 1,8-diisocyanatomethyloctane. These polyisocyanate compounds may also include modified products, derivatives, and the like. These polyisocyanate compounds can be used alone or in combination. Of these, the polyisocyanate compound is preferably MDI, TDI, or a modified product or derivative of MDI or TDI, and more preferably monomeric MDI or crude MDI.

[0024] ·catalyst As the catalyst, a known catalyst that promotes the urethane reaction can be used. More specifically, examples of the catalyst include metal catalysts such as tin-based catalysts and lead-based catalysts; amine-based catalysts; acidic catalysts; and basic catalysts. These catalysts can be used alone or in combination.

[0025] 1-1-2. Characteristics of urethane prepolymer Urethane bond amount The urethane bond content of a urethane prepolymer according to the present disclosure refers to the amount of urethane bonds contained in the urethane prepolymer. The urethane bond content of the urethane prepolymer can be adjusted by the hydroxyl value of the polyol compound and the number of isocyanate groups contained in the polyisocyanate compound, which are blended as raw materials for the urethane prepolymer. That is, the urethane bond content of the urethane prepolymer can be adjusted by the isocyanate index of the raw materials for the urethane prepolymer, which will be described later.

[0026] The urethane bond content of the urethane prepolymer is preferably 0.90 mol / kg or more, more preferably 1.00 mol / kg or more, 1.10 mol / kg or more, 1.20 mol / kg or more, or 1.30 mol / kg or more. The upper limit of the urethane bond content contained in the urethane prepolymer is not particularly limited, but is, for example, 5.00 mol / kg or less, 4.00 mol / kg or less, 3.00 mol / kg or less, 2.50 mol / kg or less, 2.00 mol / kg or less, or 1.50 mol / kg or less. When the urethane bond content contained in the urethane prepolymer is within this range, the moisture-curable hot melt adhesive composition can have better moist heat aging properties.

[0027] The urethane bond amount is calculated by the following method. This method covers all polyol compounds and all polyisocyanate compounds that are raw materials for the urethane prepolymer. The blending amounts (mass) of each polyol compound and each polyisocyanate compound are determined so that the NCO% of the urethane prepolymer is the desired value when the mass of the urethane prepolymer is 1 kg. The blending amount (mass) of each polyol compound is divided by the molecular weight of each polyol compound, and then multiplied by the number of functional groups of each polyol compound to calculate the number of moles of hydroxyl groups contained in all polyol compounds. This number of moles of hydroxyl groups is taken as the urethane bond amount of the urethane prepolymer, assuming that all of these hydroxyl groups have reacted with the isocyanate groups of the polyisocyanate compounds to form urethane bonds.

[0028] Ester bond content The ester bond amount of the urethane prepolymer according to the present disclosure refers to the amount of ester bonds contained in the urethane prepolymer. The bond amount of the urethane prepolymer can be adjusted by the amount of the polyester polyol compound added.

[0029] The amount of ester bonds is measured by the following method. This method covers all polyol compounds and all polyisocyanate compounds that are raw materials for the urethane prepolymer. The blending amounts (mass) of each polyol compound and each polyisocyanate compound are determined so that the NCO% of the urethane prepolymer is the desired value when the mass of the urethane prepolymer is 1 kg. The blending amounts (mass) of all polyester polyol compounds to be blended are divided by the number average molecular weight of each polyester polyol to calculate the blending amount (number of moles) of each polyester polyol. The calculated blending amount (number of moles) of each polyester polyol is divided by the molecular weight per structural unit of the repeating structure in each polyester polyol, and multiplied by the number of ester groups contained per structural unit of the repeating structure in each polyester polyol to calculate the ester bond amount of each polyester polyol. The ester bond amounts of each polyester polyol compound are summed to calculate the ester bond amount of the urethane prepolymer. Here, for example, in the case of a polyester polyol composed of a polycarboxylic acid compound and a polyol compound, a single repeating structure composed of these compounds is defined as one constituent unit of the repeating structure. In this case, when the polycarboxylic acid is a dicarboxylic acid and the polyol compound is a diol, for example, the molecular weight per constituent unit of the repeating structure refers to the mass of the structure obtained by subtracting the mass of [(2 hydrogen atoms + 1 oxygen atom) × 2] from the sum of the molecular weight of the polycarboxylic acid compound and the molecular weight of the polyol compound.

[0030] The amount of ester bonds in the urethane prepolymer is not particularly limited, but the upper limit is preferably 6.00 mol / kg or less, 5.00 mol / kg or less, 4.00 mol / kg or less, or 3.50 mol / kg or less, and the lower limit is preferably 0.50 mol / kg or more, 1.00 mol / kg or more, 1.50 mol / kg or more, or 1.70 mol / kg or more. The urethane prepolymer does not need to contain ester bonds (the amount of ester bonds may be 0.00 mol / kg), but when the amount of ester bonds contained in the urethane prepolymer is within this range, the moisture-curable hot melt adhesive composition can be cured to have better humidity and heat aging properties. When the urethane prepolymer contains ester bonds, the upper limit of [ester bond amount in urethane prepolymer] / [urethane bond amount in urethane prepolymer] is preferably 10.0 or less, 7.5 or less, 5.0 or less, 4.5 or less, 4.0 or less, 3.5 or less, or 3.2 or less, and the lower limit is preferably 0.1 or more, 0.2 or more, 0.5 or more, 1.0 or more, or 1.1 or more.

[0031] ·Number average molecular weight The number-average molecular weight of the urethane prepolymer is not particularly limited as long as it does not impair the effects of the present disclosure, and can be 3,000 to 8,000. By adjusting the number-average molecular weight of the urethane prepolymer, it is possible to adjust the properties of the cured product obtained by curing the moisture-curable hot melt adhesive composition, such as the adhesive strength. The number-average molecular weight of the urethane prepolymer can be measured by gel permeation chromatography (GPC) (using polystyrene as the standard polymer).

[0032] ·viscosity The viscosity of the urethane prepolymer is not particularly limited as long as it does not impair the effects of the present invention. For example, the melt viscosity of the urethane prepolymer at 140°C can be set to 2,000 to 6,000 mPa·s. By adjusting the viscosity of the urethane prepolymer, it is possible to adjust the properties of the moisture-curable hot melt adhesive composition, such as its coatability. The melt viscosity of the urethane prepolymer at 140°C is measured using a rheometer (Anton Paar, MCR302) equipped with parallel plates, by heating the sample to 140°C under conditions of a frequency of 1 Hz and a shear rate of 1 rad / s.

[0033] Isocyanate group content (NCO%) The NCO% of the urethane prepolymer is not particularly limited as long as the effects of the present disclosure are not impaired, but is preferably 0.3% to 3.5%, and more preferably 1.2% to 2.5%. When the NCO% of the urethane prepolymer is within this range, it is possible to promote moisture-induced curing while suppressing foaming during processing, and further to improve the humidity and heat aging properties of the cured product obtained by curing the moisture-curable hot melt adhesive composition. The NCO% (isocyanate group content) of the prepolymer can be measured in accordance with Method A (toluene / dibutylamine, hydrochloric acid method) of JIS K1603-1:2007, "Test Method for Aromatic Isocyanates in Plastics - Polyurethane Raw Materials, Part 1: Determination of Isocyanate Group Content."

[0034] Gel fraction The gel fraction of the urethane prepolymer is not particularly limited as long as the effects of the present disclosure are not impaired, but the lower limit is preferably 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, or 70% by mass or more, and the upper limit is 95% by mass or less, 90% by mass or less, or 85% by mass or less. By setting the gel fraction in such a range, the moisture-curable hot melt adhesive composition can have better moist heat aging properties.

[0035] The gel fraction is calculated by the following method. A predetermined amount (e.g., 0.045 g) of the moisture-curable hot melt adhesive composition is weighed out, immersed in a predetermined amount (e.g., 9 g) of tetrahydrofuran (THF), and left to stand for 20 hours. The insoluble portion of the cured material that did not dissolve and remained in the THF is removed, vacuum dried, and its mass is measured. The gel fraction is calculated by dividing the mass by the mass of the cured material before immersion.

[0036] 1-2. Carbodiimide compounds The moisture-curable hot melt adhesive composition of the present disclosure may contain a carbodiimide compound. The carbodiimide compound according to the present disclosure is not particularly limited as long as it is a compound having a carbodiimide group. Examples of the carbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide, cyanamide, N,N'-diisopropylcarbodiimide, N,N'-dicyclohexylcarbodiimide, N-cyclohexylcarbodiimide, N'-methylpolystyrene, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and metho-p-toluene. Examples include 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide sulfonate, bis(2,6-diisopropylphenyl)carbodiimide, bis(trimethylsilyl)carbodiimide, 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-p-toluenesulfonate, N,N'-di-tert-butylcarbodiimide, and 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide methiodide. Examples of commercially available products include Carbodilite (registered trademark) E-02, E-03A, E-05, E-pellet, HMV-15CA, HMV-5CA-LC, LA-1, SV-02, SW-12G, V-02, V-02B, V-02-L2, V-03, V-04, V-05, V-07, V-09, V-09GB, and V-10 manufactured by Nisshinbo Chemical Inc.; Stavaxol (registered trademark) I, P, and P100 manufactured by Rhein Chemie; LUBIO AS 15, LUBIO AS1-SP, and LUBIO AS 4 manufactured by Schaefer; and Elastostab H01 manufactured by BASF. These carbodiimide compounds can be used alone or in combination. When the moisture-curable hot melt adhesive composition contains a carbodiimide compound, the moisture-curable hot melt adhesive composition can have even better moist heat aging properties as a cured product.

[0037] The molecular weight or number average molecular weight of the carbodiimide compound is not particularly limited as long as it does not impair the effects of the present disclosure, but is preferably 300 to 10,000, more preferably 400 to 8,000, even more preferably 500 to 8,000, and particularly preferably 500 to 5,000. When the molecular weight or number average molecular weight of the carbodiimide compound is within this range, the moisture-curable hot melt adhesive composition can have even better moisture-heat aging properties as a cured product. Furthermore, the carbodiimide compound volatilized from the moisture-curable hot melt adhesive composition or its cured product may adhere to surrounding objects in the usage environment, causing the surfaces to become cloudy. For example, when used to bond interior trim of an automobile, the carbodiimide compound may cloud the automobile windows. By setting the molecular weight or number-average molecular weight of the carbodiimide compound to 500 or more, the occurrence of such clouding can be easily prevented.

[0038] 1-3.Other additives The moisture-curable hot melt adhesive composition of the present disclosure may contain other additives as needed. The other additives are not particularly limited and include known components contained in moisture-curable hot melt adhesive compositions. Examples of the other additives include fillers, plasticizers, pigments, dyes, antioxidants, antioxidants, defoamers, crystal nucleating agents, antistatic agents, flame retardants, adhesion promoters, antibacterial agents, light stabilizers, stabilizers, dispersants, solvents, hydrophilicity promoters, waxes, etc. These additives may be used alone or in combination.

[0039] 2. Method for producing moisture-curable hot melt adhesive composition 2-1. Urethane prepolymer manufacturing method The method for producing the urethane prepolymer is not particularly limited, and known methods can be used. Specifically, for example, a predetermined amount of polyisocyanate compound is placed in a container and stirred under a nitrogen gas atmosphere. A predetermined amount of polyol compound is then added dropwise. Here, a catalyst can be added as needed to promote the reaction. The reaction is completed by stirring for a predetermined period of time. At this stage, a portion of the reaction product may be sampled and the isocyanate group content measured to confirm that it is within the desired range.

[0040] The amounts of the polyol compound and the polyisocyanate compound to be mixed are not particularly limited, but for example, they can be mixed so that the isocyanate index of the urethane prepolymer is 0.5 to 2.0, preferably 1.0 to 2.0, and more preferably 1.2 to 1.6. Here, the isocyanate index refers to the ratio of the number of moles of all active hydrogens in the resin composition, which is the blend of all raw materials for the urethane prepolymer, to the number of moles of isocyanate groups in the polyisocyanate compound (number of moles of isocyanate groups / number of moles of active hydrogen).

[0041] The amount of catalyst added is not particularly limited, but can be, for example, 0.01 to 5.0 parts by mass when the total amount of polyol compounds is 100 parts by mass.

[0042] 2-2. Method for producing moisture-curable hot melt adhesive composition When additives other than the urethane prepolymer are added, the method for producing the moisture-curable hot melt adhesive composition is not particularly limited, and any known method can be used. Specifically, for example, a predetermined amount of the urethane prepolymer is placed in a container, and the carbodiimide compound and other additives are added thereto and stirred.

[0043] The amount of the carbodiimide compound is not particularly limited as long as it does not impair the effects of the present disclosure. The amount of the carbodiimide compound is preferably 0.1 parts by mass or more, 0.5 parts by mass or more, 1.0 parts by mass or more, 1.5 parts by mass or more, 2.0 parts by mass or more, 2.5 parts by mass or more, or 3.0 parts by mass or more, based on 100 parts by mass of the total amount of the polyol compounds blended into the urethane prepolymer. It is also preferably 10.0 parts by mass or less, 8.0 parts by mass or less, 6.0 parts by mass or less, or 5.0 parts by mass or less. For example, based on 100 parts by mass of the total amount of the polyol compounds blended into the urethane prepolymer, the amount can be 0.1 to 10.0 parts by mass, preferably 1.0 to 10.0 parts by mass, more preferably 1.0 to 8.0 parts by mass, even more preferably 1.0 to 6.0 parts by mass, even more preferably 1.0 to 5.0 parts by mass, and particularly preferably 3.0 to 5.0 parts by mass. When the moisture-curable hot melt adhesive composition contains a carbodiimide compound in this range, the moisture-curable hot melt adhesive composition can have even better moist heat aging properties when cured. The amount (total amount) of other additives (additives other than urethane prepolymer and carbodiimide compound) is not particularly limited as long as it does not impair the effects of the present disclosure, but for example, when the total amount of polyol compounds blended into the urethane prepolymer is 100 parts by mass, it can be 10.0 parts by mass or less, 5.0 parts by mass or less, 3.0 parts by mass or less, 2.0 parts by mass or less, or 1.0 part by mass or less, or it can be 0.1 parts by mass or more, 0.2 parts by mass or more, 0.3 parts by mass or more, 0.4 parts by mass or more, or 0.5 parts by mass or more.

[0044] 3. Uses of moisture-curable hot melt adhesive compositions The moisture-curable hot melt adhesive composition is suitable for use in, for example, architectural interior materials such as decorative sheet covering materials, furniture materials, and interior materials for automobiles, trains, ships, aircraft, etc. (for example, for bonding sewn portions of seat and headrest cover pads, etc.) It is particularly suitable for use in automobile interior materials used in high-temperature and high-humidity environments.

[0045] The moisture-curable hot melt adhesive composition can be applied to an object by heating and melting it. Known methods can be used for application, including, for example, application methods using a brush, spatula, syringe, sealing gun, dispenser, etc. Furthermore, since the moisture-curable hot melt adhesive composition of the present disclosure can have a low melt viscosity, it can also be applied using a non-contact method (e.g., a spray method). From the viewpoints of improving breathability and productivity (e.g., ease of manufacturing even for long objects), it is preferable to apply the adhesive to the object by spray application. The amount of the moisture-curable hot melt adhesive composition applied (or the basis weight of the moisture-curable hot melt adhesive composition) is 1 to 100 g / m 2 It is preferable that the density is 3 to 50 g / m 2 More preferably, it is 5 to 30 g / m 2 It is particularly preferred that:

[0046] The technology according to the present disclosure may be provided as a cured product of the moisture-curable hot melt adhesive composition, or as a laminate including the cured product of the moisture-curable hot melt adhesive composition. For example, the technology according to the present disclosure may be a laminate in which a first substrate and a second substrate are laminated via an adhesive layer, and this adhesive layer is a cured product of the moisture-curable hot melt adhesive composition according to the present disclosure. In this case, the materials and shapes of the first substrate and the second substrate are not particularly limited, but it is preferable that the first substrate and the second substrate are each independently selected from the group consisting of a foam (e.g., urethane foam), natural leather, synthetic leather, a film (resin film), a woven fabric, and a nonwoven fabric. Such a laminate can be produced by applying the above-mentioned method for applying the moisture-curable hot melt adhesive composition. Such a laminate can be used as a building interior material such as the decorative sheet covering material described above, a furniture material, or a component constituting the interior materials of automobiles, trains, ships, aircraft, etc. [Example]

[0047] The effects of the moisture-curable hot melt adhesive composition of the present disclosure will be specifically described below using examples. Table 1 shows the raw materials for the moisture-curable hot melt adhesive compositions produced in each of the Examples and Comparative Examples, as well as the evaluation results of the resulting moisture-curable hot melt adhesive compositions.

[0048] <Production of Moisture-Curable Hot Melt Adhesive Composition> MDI was added as a polyisocyanate compound in the amount shown in Table 1 to a 1-liter four-neck flask equipped with a stirring blade. The flask was purged with nitrogen gas and then heated to 80°C. Next, polyol compounds were added to the flask in the amounts shown in Table 1, heated to 80°C, and the molten state was added. The mixture was stirred for at least 2 hours under a nitrogen gas atmosphere while maintaining the liquid temperature at 100°C or below. This allowed the polyol compound and polyisocyanate compound to react, yielding a urethane prepolymer. Furthermore, a carbodiimide compound and other additives were blended according to Table 1, and the mixture was stirred for at least 2 hours to obtain the moisture-curable hot melt adhesive compositions of each example and comparative example.

[0049] The raw materials of the moisture-curable hot melt adhesive composition used are listed below. Polyol compounds Polyester Polyol Polyol 1: Reaction compound of sebacic acid (SA) and 1,6-hexanediol (HD), number average molecular weight 5,000 Polyol 2: Reaction product of adipic acid (AA) and 1,6-hexanediol (HD), number average molecular weight 4,500 Polyol 3: A reaction product of adipic acid (AA) and terephthalic acid with ethylene glycol and 1,4-butylene glycol (BG), number average molecular weight 3,000 Polyol 4: Reaction product of 1,12-dodecanedioic acid (DDA) and 1,6-hexanediol (HD), number average molecular weight 3,700 Polyol 5: A reaction product of adipic acid (AA) and 1,4-butanediol (BD), number average molecular weight 2,000 Polyether polyol Polyol 6: Polypropylene glycol (PPG), number average molecular weight 1,000 Polyol 7: Polypropylene glycol (PPG), number average molecular weight 700 Polyol 8: Copolymer of bisphenol A (BP) and propylene oxide (PO), number average molecular weight 500 ·wax (1) Microcrystalline wax Hi-Mic-2095 manufactured by Nippon Seiro Co., Ltd. Extinguishing agent (1) San Nopco Dappo SN348 Anti-aging agent (1) BASF IRGANOX 1076 (2) BASF IRGAFOS168 ·catalyst (1) DMDEE (amine catalyst, dimorpholinodiethyl ether) Nucleating agent (1) ADEKA NA11 Polyisocyanate compounds (1) Monomeric MDI, molecular weight: 250 Carbodiimide compounds (1) Carbodilite V04PF manufactured by Nisshinbo Chemical Co., Ltd., number average molecular weight: 2,000 (2) Stavaxol I, manufactured by Rhein Chemie, number average molecular weight: 380 (3) Rhein Chemie AG, Stavaxol P, number average molecular weight: 2,000 (4) Schaefer LUBIO AS 15, number average molecular weight: 1,500 (5) Carbodilite HMV-15CA manufactured by Nisshinbo Chemical Co., Ltd., number average molecular weight: 3,400 (6) BASF Elastostab H01 Number average molecular weight: 1,900

[0050] <Evaluation and measurement> NCO% of urethane prepolymer The NCO% of the urethane prepolymer in each example and comparative example was measured in accordance with Method A (toluene / dibutylamine, hydrochloric acid method) of JIS K1603-1:2007 "Plastics - Polyurethane raw material aromatic isocyanate test method, Part 1: Determination of isocyanate group content."

[0051] ·Isocyanate index of urethane prepolymer The isocyanate index of the urethane prepolymer of each example and comparative example is shown.

[0052] ·Compatibility The compatibility of the carbodiimide compound and the urethane prepolymer in the moisture-curable hot melt adhesive compositions of each Example and Comparative Example containing a carbodiimide compound was observed with the naked eye. For the urethane prepolymer of each Example and Comparative Example, the carbodiimide compound of each Example and Comparative Example was added under a nitrogen gas atmosphere, and the mixture was stirred for 1 hour to prepare an evaluation sample. The evaluation criteria were as follows. Furthermore, cases without a carbodiimide compound were marked with "-". ○: No suspension of urethane prepolymer was observed with the naked eye ×: Suspension of urethane prepolymer was observed with the naked eye

[0053] Urethane bond amount of urethane prepolymer The amount of urethane bond in the urethane prepolymer of each example and comparative example was calculated by the method described above.

[0054] Ester bond amount of urethane prepolymer The amount of ester bonds in the urethane prepolymers of the examples and comparative examples was calculated by the method described above.

[0055] Gel fraction of urethane prepolymer The moisture-curable hot melt adhesive composition of each Example and Comparative Example was applied to a release-treated PET film and cured to obtain a cured product of each Example and Comparative Example. 0.045 g of the resulting cured product was weighed out, immersed in 9 g of tetrahydrofuran (THF), and allowed to stand for 20 hours. The insoluble portion of the cured product remaining in the THF was removed, vacuum dried, and its mass was measured. The mass was divided by 0.045 g to calculate the gel fraction of the urethane prepolymer.

[0056] Glass haze level The moisture-curable hot melt adhesive composition of each Example and Comparative Example was melted at 130°C and applied at a rate of 20 g / m using a hand gun. 2 The coating was sprayed onto urethane foam (EL-67F manufactured by Inoac Corporation) so that the coating was uniform. The urethane foam was then bonded to a fabric (PET) skin and cured at room temperature for 12 hours to obtain a laminate. The laminate was then processed to a diameter of 80 mm and a thickness of 250 μm to prepare a test specimen for evaluation. The test specimen was placed at the bottom of a 90 mm diameter x 190 mm high glass container (a container with only the top open). A glass dish was placed on top of the test specimen (inside the glass container), and 1 ml of a 0.012 g / ml ethylenediamine aqueous solution was placed in the glass dish. The glass container was then covered with a 90 mm diameter glass plate to seal the top, and the container was left in a constant temperature bath at 80°C for 72 hours. The glass plate was then removed, and the reflectance of the treated glass plate was measured using a gloss meter. The glass haze was calculated using the reflectance of the glass plate measured before treatment according to the following formula: The reflectance before and after the treatment was measured nine times for each glass plate, and the average value was calculated. (Formula 1) Glass haze index = reflectance of glass plate after treatment / reflectance of glass plate before treatment x 100 The degree of glass haze was evaluated according to the following criteria. 〇: 90.0% or more △: 70.0% or more to less than 90.0% ×: Less than 70.0%

[0057] ·Moist heat aging The moisture-curable hot melt adhesive composition of each Example and Comparative Example was melted at 130°C and applied at a rate of 20 g / m using a hand gun. 2 The coating was applied to urethane foam (EL-67F, manufactured by Inoac Corporation) so that the coating was uniform. The urethane foam was then bonded to a surface made of fabric (PET fabric) to obtain a laminate. Each laminate was subjected to moist heat treatment for 200, 400, or 600 hours at 85°C and 95% relative humidity. After treatment, each laminate was molded into a 25 mm wide x 250 mm long specimen and left to stand at room temperature for 12 hours to prepare a test specimen for evaluation. The specimens were subjected to a 180° peel test at 25°C using a materials testing machine (Shimadzu Corporation, precision universal testing machine autograph) to measure the peel strength under each moist heat treatment condition. The peel strength was evaluated after treatment times of 200 hours, 400 hours, and 600 hours, and was scored according to the following criteria. 3 points: Peel strength is 2.5N / 25mm or more 2 points: Peel strength is 1.3N / 25mm or more but less than 2.5N / 25mm 1 point: Peel strength is less than 1.3N / 25mm The evaluation scores for peel strength when the wet heat treatment time was 200 hours, 400 hours, and 600 hours were added together to form an overall evaluation, which was evaluated according to the following evaluation criteria. 〇: The total score at 200 hours, 400 hours, and 600 hours is 7 to 9 points △: The total score at 200 hours, 400 hours, and 600 hours is 4 to 6 points. ×: The total score at 200 hours, 400 hours, and 600 hours is 3 points or less

[0058] [Table 1]

[0059] Furthermore, laminates were produced using the moisture-curable hot melt adhesive compositions of Examples 1, 11, and 12 in the same manner as above, except that the objects to be adhered were changed from urethane foam and fabric to the substrates (upper and lower layers) shown in Table 2. The results of the evaluation were shown in Table 2. In Table 2, "Fabric" refers to PET fabric, and "EL-45" is a urethane foam manufactured by Inoac Corporation.

[0060] [Table 2]

Claims

1. A moisture-curable hot melt adhesive composition comprising a urethane prepolymer, The urethane prepolymer is obtained by reacting a polyol compound with a polyisocyanate compound, the urethane bond amount of the urethane prepolymer is 0.90 mol / kg or more, further comprising a carbodiimide compound; The moisture-curable hot melt adhesive composition, wherein the molecular weight or number average molecular weight of the carbodiimide compound is 500 or more.

2. The moisture-curable hot melt adhesive composition according to claim 1 , wherein the polyol compound comprises a polyether polyol compound and a polyester polyol compound.

3. 3. The moisture-curable hot melt adhesive composition according to claim 1, wherein the urethane prepolymer has an ester bond amount of 6.00 mol / kg or less.

4. 3. The moisture-curable hot melt adhesive composition according to claim 1, which is used for automobile interior materials.

5. The first substrate and the second substrate are laminated together via an adhesive layer, The adhesive layer is a cured product of the moisture-curable hot melt adhesive composition according to claim 1 or 2, A laminate, wherein the first substrate and the second substrate are each independently selected from the group consisting of a foam, natural leather, synthetic leather, a film, a woven fabric, and a nonwoven fabric.

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