JP5907377B2 - Moisture curable polyurethane hot melt resin composition - Google Patents

Description

  The present invention relates to a moisture-curable polyurethane hot melt resin composition having excellent durability such as heat resistance, heat and humidity resistance, and weather resistance.

Adhesives using moisture-curable polyurethane hot melt resin compositions are widely used for bonding building members from the viewpoint of productivity, yield, surface appearance, and the like.
Conventionally, Lauan plywood has been used as a base material for building materials, but in recent years, MDF (Medium Density Fiber Board) and particle board are widely used from the viewpoint of design and durability. It's being used.

  As an adhesive using a moisture curable polyurethane hot melt resin composition used for a substrate such as MDF or particle board, a composition containing a crystalline polyester polyol (A) and an amorphous polyester polyol (B) and a polycrystal It is reacted with isocyanate (F), and is cooled at a cooling rate of 500 ° C./min from the melting temperature to 50 ° C. by differential thermal analysis, and then held at 50 ° C., the half crystallization time is 150 seconds. A moisture-curable polyurethane hot melt adhesive having a heat of crystallization of 30 to 90 J / g is disclosed (for example, see Patent Document 1).

  However, although the moisture-curable polyurethane hot melt adhesive has an initial adhesive strength of a practically usable level, the cohesive strength is insufficient, and heat resistance, moisture and heat resistance, and a laminate using the adhesive Durability such as weather resistance was insufficient.

WO2008 / 26513

  The problem to be solved by the present invention is to provide a moisture-curable polyurethane hot melt resin composition having excellent heat resistance, heat-and-moisture resistance and weather resistance.

  The inventors of the present invention have intensively studied the polyol to be used while advancing research to solve the above problems. As a result, the inventors have found that the above problem can be solved by using a specific polyol, and have found the present invention.

  That is, the present invention is a moisture curable polyurethane hot melt resin composition containing a urethane prepolymer having an isocyanate group obtained by reacting a polyol (A) and a polyisocyanate (B), wherein the polyol (A ) Contains aliphatic polyester polyol (A-1), aromatic polyester polyol (A-2), polycaprolactone polyol (A-3), acrylic polyol (A-4), and polycarbonate polyol (A-5). The present invention provides a moisture curable polyurethane hot melt resin composition.

  The moisture curable polyurethane hot melt resin composition of the present invention is excellent in heat resistance, moist heat resistance and weather resistance. In addition, the moisture-curable polyurethane hot melt resin composition of the present invention has low viscosity and is excellent in coating suitability.

  The aliphatic polyester polyol (A-1) is obtained by reacting an aliphatic diol and an aliphatic dibasic acid, and is essential for imparting the initial strength, initial creep property, and durability of the adhesive. It is an ingredient.

  Examples of the aliphatic diol include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, neopentyl glycol, diethylene glycol, and the like. . These aliphatic diols may be used alone or in combination of two or more. Among these, 1,6-hexanediol is preferable from the viewpoint of durability and the like.

  Examples of the aliphatic dibasic acid include adipic acid, succinic acid, sebacic acid, dodecane methylene carboxylic acid, dodecanedioic acid, fumaric acid, icosapentaenoic acid, maleic acid and the like. These aliphatic dibasic acids may be used alone or in combination of two or more. Among these, adipic acid, sebacic acid, and dodecanedioic acid are preferable from the viewpoint of durability and the like.

  As the aliphatic polyester polyol (A-1), those obtained by a known and commonly used method can be used.

  The number average molecular weight of the aliphatic polyester polyol (A-1) is preferably in the range of 1,000 to 5,000, particularly preferably in the range of 2,000 to 4,000, from the viewpoint of durability and the like. In addition, the number average molecular weight of the said aliphatic polyester polyol shows the value obtained by measuring as follows by a gel permeation chromatography (GPC) method.

Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4 mass%)
Standard sample: A calibration curve was prepared using the following monodisperse polystyrene.

(Monodispersed polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation

  The aromatic polyester polyol (A-2) is obtained by reacting the aliphatic diol and / or aromatic diol with the aliphatic dibasic acid and / or aromatic dibasic acid, and is bonded. It is an essential component for imparting initial strength and durability of the agent, strength at the time of melting, and the like.

  Examples of the aromatic diol include bisphenol A, bisphenol F, and ethylene oxide adducts thereof.

  Examples of the aromatic dibasic acid include phthalic acid, terephthalic acid, phthalic anhydride, orthophthalic acid,

  In the present invention, the aliphatic dibasic acid may be used in combination with the aromatic dibasic acid.

  The said aromatic polyester polyol (A-2) can use what is obtained by a well-known and usual method.

  The number average molecular weight of the aromatic polyester polyol (A-2) is preferably in the range of 500 to 5,000, particularly preferably in the range of 1,000 to 4,000, from the viewpoint of durability and the like. In addition, the number average molecular weight (A-2) of the said aromatic polyester polyol is the same as the measuring method of the number average molecular weight of the said aliphatic polyester polyol (A-1).

  The amount of the aromatic polyester polyol (A-2) used is preferably in the range of 10 to 60 parts by mass with respect to 100 parts by mass of the aliphatic polyester polyol (A-1), from the viewpoint of durability and the like. A range of 25 to 40 parts by mass is particularly preferable.

  The polycaprolactone polyol (A-3) is an essential component for imparting initial strength, initial creep properties, durability, and moderate moisture curability. For example, ε-caprolactone is present in the presence of an initiator and a catalyst. Those obtained by ring-opening polymerization of can be used.

  Examples of the initiator include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, bisphenol A ethylene oxide or propylene oxide adduct And trivalent alcohols such as trimethylolpropane, trimethylolethane, and glycerin can be used.

  The catalyst is, for example, an organic titanium compound such as tetrabutyl titanate, tetrapropyl titanate, or tetraethyl titanate, or a tin compound such as tin octylate, dibutyltin oxide, dibutyltin laurate, stannous chloride, or stannous bromide. A compound or the like can be used.

  Specifically, the polycaprolactone polyol (A-3) is produced by mixing the initiator and ε-caprolactone under a nitrogen gas atmosphere, and then adding the catalyst to the total amount of ε-caprolactone. On the other hand, about 0.1-100 ppm is mixed and it can manufacture by making it react at about 150-200 degreeC for about 4 to 10 hours.

  In the product obtained by the above production method, a polycaprolactone polyol having a relatively low molecular weight may be mixed. In such a case, if necessary, those from which they are removed may be used.

  The number average molecular weight of the polycaprolactone polyol (A-3) is preferably in the range of 20,000 to 200,000, more preferably in the range of 30,000 to 10,000, from the viewpoint of improving the initial creep property. A range of 30,000 to 50,000 is particularly preferred. In addition, the number average molecular weight of the said polycaprolactone polyol (A-3) is the same as the measuring method of the number average molecular weight of the said aliphatic polyester polyol (A-1).

  The amount of the polycaprolactone polyol (A-3) used is preferably in the range of 1 to 20 parts by mass with respect to 100 parts by mass of the aliphatic polyester polyol (A-1) from the viewpoint of durability and the like. The range of 10 to 10 parts by mass is particularly preferable.

  The acrylic polyol (A-4) is obtained by polymerizing a (meth) acrylic compound, and is an essential component for imparting initial strength and durability, and adhesion to substrates such as MDF and particle board. is there. In the present invention, “(meth) acrylic compound” refers to one or both of a methacrylic compound and an acrylic compound.

  Examples of the (meth) acrylic compound include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, Neopentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cetyl (meth) acrylate, lauryl (meth) acrylate, isobonyl (meth) ) Acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 2- ( Full Looctyl) ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, cyclohexyl (meth) acrylate, sidiclopentanyl (meth) acrylate, dicyclopentenyloxy Ethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, methoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, benzyl (meth) acrylate 2-ethyl-2-methyl- [1,3] -dioxolan-4-yl-methyl (meth) acrylate, dimethylaminoethyl (meth) acrylate Over bets can be used isobornyl (meth) acrylate. These (meth) acrylic compounds may be used alone or in combination of two or more. Among these, it is preferable to use methyl (meth) acrylate, n-butyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate from the viewpoint of adhesiveness to substrates such as MDF and particle board.

  The number average molecular weight of the acrylic polyol (A-4) is preferably from 500 to 5,000, particularly preferably from 1,000 to 3,000, from the viewpoint of adhesiveness to a substrate such as MDF or particle board. In addition, the number average molecular weight of the said acrylic polyol (A-4) is the same as that of the measuring method of the number average molecular weight of the said aliphatic polyester polyol (A-1).

  As the usage-amount of the said acrylic polyol (A-4), 20-50 mass parts with respect to 100 mass parts of said aliphatic polyester polyol (A-1) from an adhesive viewpoint with respect to base materials, such as MDF and a particle board. The range of 30-40 mass parts is especially preferable.

  In addition, the mass ratio [(A-3) / (A-4)] of the polycaprolactone polyol (A-3) and the acrylic polyol (A-4) further increases durability, low viscosity, and coating suitability. From the viewpoint of improvement, the range of 5/95 to 50/50 is preferable, the range of 5/95 to 30/70 is more preferable, and the range of 10/90 to 20/80 is particularly preferable.

  The polycarbonate polyol (A-5) is an essential component for imparting durability. For example, a polycarbonate polyol (A-5) obtained by reacting a carbonate ester and / or phosgene with a compound having a hydroxyl group described later is used. Can do.

  Examples of the carbonate ester include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, diphenyl carbonate, and the like.

  Examples of the compound having a hydroxyl group include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propanediol, dipropylene glycol, tripropylene glycol, butanediol, pentanediol, 1,6-hexanediol, 2,5- Hexanediol, heptanediol, octanediol, nonanediol, decanediol, undecanediol, dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, hydroquinone, resorcin, bisphenol A Bisphenol F or the like can be used. Among these, from the viewpoint of further improving heat resistance, moist heat resistance, and weather resistance, those having no alicyclic structure are preferably used, and 1,6-hexanediol is particularly preferable.

  The number average molecular weight of the polycarbonate polyol (A-5) is preferably from 500 to 5,000, particularly preferably from 1,000 to 3,000, from the viewpoint of low viscosity. In addition, the number average molecular weight of the said polycarbonate polyol (A-5) is the same as the measuring method of the number average molecular weight of the said aliphatic polyester polyol (A-1).

  As the usage-amount of the said polycarbonate polyol (A-5), the viewpoint of low viscosity, durability, etc. has the range of 5-30 mass parts with respect to 100 mass parts of the said aliphatic polyester polyol (A-1). The range of 5 to 25 parts by mass is more preferable, and the range of 20 to 25 parts by mass is particularly preferable.

  Examples of the polyol (A) include the aliphatic polyester polyol (A-1), the aromatic polyester polyol (A-2), the polycaprolactone polyol (A-3), the acrylic polyol (A-4), and Although containing the said polycarbonate polyol (A-5), you may use another polyol together as needed.

  Examples of the other polyol include polybutadiene polyol, hydrogenated polybutadiene polyol, dimer diol, polyether polyol, and rosin polyol.

  Examples of the polyisocyanate (B) include polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate isocyanate, phenylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, and the like, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane. Aliphatic or alicyclic polyisocyanates such as diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate can be used. Among these, diphenylmethane diisocyanate is preferable from the viewpoint of reactivity and adhesiveness.

  The amount of the polyisocyanate (B) used is preferably in the range of 10 to 50% by mass in the moisture-curable polyurethane hot melt adhesive of the present invention from the viewpoint of viscosity and the like, and is preferably 15 to 30% by mass. The range of is more preferable.

  Next, the urethane prepolymer used in the present invention will be described.

  The urethane prepolymer is obtained by reacting the polyol (A) and the polyisocyanate (B), and reacts with moisture present in the air or in the base material to which the urethane prepolymer is applied. It has an isocyanate group capable of forming a crosslinked structure at the polymer end or in the molecule.

  As a method for producing the urethane prepolymer, for example, a mixture of the polyol (A) is dropped into a reaction vessel containing the polyisocyanate (B) and then heated, and the isocyanate group of the polyisocyanate (B) is changed. , And can be produced by reacting under an excess condition with respect to the hydroxyl group of the polyol (A).

  When producing the urethane prepolymer, the equivalent ratio of the isocyanate group of the polyisocyanate (B) to the hydroxyl group of the polyol (A) ([isocyanate group / hydroxyl group]) is heat resistance, moist heat resistance, weather resistance. From the viewpoint of property, a range of 1.1 to 5.0 is preferable, a range of 2.0 to 3.5 is more preferable, and a range of 2.45 to 2.50 is particularly preferable.

  The urethane prepolymer can be usually produced without a solvent, but may be produced by reacting the polyol (A) and the polyisocyanate (B) in an organic solvent. When reacting in an organic solvent, an organic solvent such as ethyl acetate, n-butyl acetate, methyl ethyl ketone, and toluene that does not hinder the reaction can be used, but by a method such as heating under reduced pressure during or after the reaction. It is necessary to remove the organic solvent.

  When manufacturing the said urethane prepolymer, a urethanation catalyst can be used as needed. The urethanization catalyst can be appropriately added at any stage of the reaction.

  Examples of the urethanization catalyst include nitrogen-containing compounds such as triethylamine, triethylenediamine and N-methylmorpholine; metal salts such as potassium acetate, zinc stearate and tin octylate; and organometallic compounds such as dibutyltin dilaurate. Can do.

  The isocyanate group content (hereinafter referred to as NCO%) of the urethane prepolymer obtained by the above method is in the range of 2.5 to 8.0% from the viewpoint of further improving heat resistance, moist heat resistance and weather resistance. The range of 3.0 to 5.0 is more preferable, and the range of 3.5 to 4.0 is particularly preferable. In addition, NCO% of the said urethane prepolymer shows the value measured by the potentiometric titration method based on JISK1603-1.

  The number average molecular weight of the urethane prepolymer is preferably in the range of 1,000 to 30,000, more preferably in the range of 1,000 to 10,000, from the viewpoints of heat resistance, heat and humidity resistance, weather resistance, and viscosity. preferable.

  Moreover, as a viscosity of the said urethane prepolymer, it is preferable that the melt viscosity in 120 degreeC is the range of 1,000-50,000 mPa * s, and it is more preferable that it is the range of 3,000-30,000 mPa * s. preferable. The melt viscosity at 120 ° C. is a value measured with a B-type viscometer.

  The urethane prepolymer contained in the moisture curable polyurethane hot melt resin composition of the present invention has both of two characteristics, moisture crosslinking reactivity and hot melt property. The moisture cross-linking reactivity of the urethane prepolymer is derived from the cross-linking reaction initiated by the reaction between the isocyanate group of the urethane prepolymer and moisture, and is a property resulting from the isocyanate group of the urethane prepolymer.

On the other hand, the hot melt property of the urethane prepolymer is a property resulting from the molecular structure of the urethane prepolymer to be selected, and it is solid at room temperature but can be melted and applied by heating. It is a property that can solidify and develop adhesiveness when cooled.

Hot melt is a general term for properties or substances that are solid or viscous at room temperature, but melt and become fluid or liquid when heated. For example, hot melts typified by ethylene vinyl acetate are generally used. Are known. Hot melt is a solvent-free type and is a solid or viscous property at room temperature, but when heated, it melts and can be applied, and it has the property that cohesive force is produced again by cooling. It is useful as a solventless adhesive.

Hot melt properties are closely related to the softening point. In general, the lower the softening point of the urethane prepolymer, the better the workability, and conversely, the higher the softening point, the better the final adhesive strength.

  The softening point of the urethane prepolymer contained in the moisture curable polyurethane hot melt resin composition of the present invention is preferably in the range of 40 to 120 ° C. When the softening point of the urethane prepolymer is 40 ° C. or higher, the final adhesive strength is good, and when it is 120 ° C. or lower, workability is good. The softening point of the urethane prepolymer is more preferably 60 ° C. or higher, and further preferably 100 ° C. or lower. In addition, the softening point as used in the field of this invention means the temperature which begins to heat-flow and lose cohesive force, when the temperature of an ureta prepolymer is raised in steps. In addition, the softening point in this invention is the value calculated | required by the ring and ball method based on JISK5902.

  Next, the moisture curable polyurethane hot melt resin composition of the present invention will be described.

  The moisture-curable polyurethane hot melt resin composition of the present invention may be composed of only the urethane prepolymer, but may contain other additives as necessary.

  Content of the said urethane prepolymer in the said moisture hardening type polyurethane hot-melt resin composition is 50-100 mass%, More preferably, it is the range of 70-99 mass%.

  Examples of the other additives include an antioxidant, a tackifier, a plasticizer, a stabilizer, a filler, a dye, a pigment, a fluorescent brightener, a silane coupling agent, a wax, a curing catalyst, and a thermoplastic resin. Can be used. Among these, it is particularly preferable to contain an antioxidant from the viewpoint of further improving durability.

  As the antioxidant, for example, a hindered phenol-based antioxidant, a hindered amine-based antioxidant, an organic sulfur-based antioxidant, a phosphate ester-based antioxidant, or the like can be used. Among these, it is particularly preferable to use a hindered amine antioxidant and a phenolic antioxidant from the viewpoint of further improving the compatibility with the polyol (A), heat resistance, moist heat resistance, weather resistance, and the like.

  Examples of the hindered amine antioxidant include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and bis (1,2,2,6,6-pentamethyl-4-piperidyl). Sebacate, 1,2,3,4-tetrakis (2,2,6,6-tetramethyl-4-piperidyloxycarbonyl) butane, dimethyl-1- (2-hydroxylethyl-4-hydroxy-2,2) succinate , 6,6-tetramethylpiperidine polycondensate, 1- (3,5-di-t-butyl-4-hydroxyphenyl) -1,1-bis (2,2,6,6-tetramethyl-4- Piperidyloxycarbonyl) pentane, N, N-bis (3-aminopropyl) ethylenediamine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, bis (octylone-) , 2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl)- 4-hydroxyphenyl] methyl] butyl malonate and the like can be used.

  Preferred examples of the hindered amine antioxidant include “Sanol LS2626”, “Sanol LS765”, “Sanol LS770”, “Sanol LS744” (manufactured by Sankyo Lifetech Co., Ltd.), “Tinubin 144”, “Tinuvin” "622LD" (above, manufactured by Ciba Japan), "Mark LA57", "Mark LA67", "Mark LA62", "Mark LA68", "Mark LA63" (above, manufactured by Adeka) etc. are commercially available. be able to.

  Examples of the phenolic antioxidant include 2,6-di-t-butylphenol derivatives, 2-methyl-6-t-butylphenol derivatives, octadecyl 3 (3,5-dibutyl-4-bitoxyphenyl) propionate, 4, 4-butylidene-bis (6-t-butyl-m-cresol), pentaerythrityl tetrakis {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate}, 2- {1- ( 2-hydroxy-3,5-di-t-pentylphenyl) -ethyl} -4,6-di-t-pentylphenyl acrylate and the like can be used.

  Preferable examples of the phenol-based antioxidant include, for example, “Sumizer GA-80”, “Sumerator MDP-S”, “Sumerator BBM-S”, “Sumizer WX-R”, “Sumizer WX-RC” (and above). , Manufactured by Sumitomo Chemical Co., Ltd.) can be obtained as commercial products.

  Since the moisture curable polyurethane hot melt resin composition of the present invention is excellent in heat resistance, moist heat resistance and weather resistance, it can be suitably used, for example, as an adhesive or a sealant.

  Hereinafter, the present invention will be described in detail by way of examples.

[Example 1]
In a 2 liter four-necked flask, as the aliphatic polyester polyol (A-1), “Polylite MX-2523” (reaction of 1,6-hexanediol and sebacic acid, number average molecular weight: 3,500, DIC) 23 parts by mass, “CMA-64” (reacted 1,6-hexanediol and adipic acid, number average molecular weight; 2,000, manufactured by DIC) 10 parts by mass, aromatic polyester polyol , “Polylite MX-2905” (reacted with ethylene glycol, neopentyl glycol, terephthalic acid and icosapentaenoic acid, number average molecular weight; 2,600, manufactured by DIC Corporation), 3 parts by mass, “Polylite MX-2911” (diethylene glycol) 1. Reaction of phthalic anhydride with number average molecular weight; 1,000, manufactured by DIC) Parts by mass, "Polylite MX-2360T" (reacted with 6 mol adduct of bisphenol A ethylene oxide, isophthalic acid and sebacic acid, number average molecular weight; 2,000, manufactured by DIC), 5.5 parts by mass, poly As caprolactone polyol (A-3), "CAPA-6400" (number average molecular weight; 38,000, manufactured by Solvay) 3 parts by mass acrylic polyol (A-4), "M-HA-2" (methyl methacrylate 66) .65% by mass, 33% by mass of n-butyl methacrylate and 0.35% by mass of 2-hydroxyethyl methacrylate (DIC), 12 parts by mass, polycarbonate polyol (A-5), “Duranate T- 4671 "(dimethyl carbonate, 1,6-hexanediol and 1,4-butane All reacted, number average molecular weight: 1,000, manufactured by Asahi Kasei Chemicals Co., Ltd., 3.0 parts by mass, as other polyols, PPG-2000 (polypropylene glycol, number average molecular weight; 2,000) 10 parts by mass, Mixing 6 parts by mass of PPG-1000 (polypropylene glycol, number average molecular weight; 1,000) and heating under reduced pressure at 100 ° C., the water content with respect to the total amount in the 2-liter 4-necked flask becomes 0.05% by mass. Until dehydrated.
After cooling the inside of the 2 liter four-necked flask to 70 ° C., as an antioxidant, 2 parts by weight of “Tinuvin 144” (hindered amine antioxidant, manufactured by Ciba Japan Co., Ltd.), “Smilizer GA-80” ( 0.5 parts by mass of a phenolic antioxidant (manufactured by Sumitomo Chemical Co., Ltd.) was mixed and mixed with stirring. Then, 19.5 parts by mass of 4,4′-diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Millionate MT) melted at 70 ° C. is added and reacted at 110 ° C. for about 3 hours until the isocyanate group content becomes constant. As a result, a urethane prepolymer (NCO%; 3.88%) was obtained, and a moisture-curable polyurethane hot melt resin composition was obtained.

[Examples 2-5, Comparative Examples 1-2]
A moisture-curable polyurethane hot melt resin composition was obtained in the same manner as in Example 1 except that the types and / or amounts of the polyol, polyisocyanate and additives used were changed as shown in Table 1.

[Production of polyurethane hot melt adhesive film]
After the moisture-curable polyurethane hot melt adhesive obtained in Examples and Comparative Examples was heated and melted to 110 ° C. and applied to a release paper at a thickness of 100 μm using a knife coater heated to 110 ° C., A polyurethane hot melt adhesive film after moisture curing was prepared by leaving it for 3 days in an environment of a temperature of 23 ° C. and a relative humidity of 65% RH.

[Evaluation method of heat resistance]
A test piece was prepared by cutting the polyurethane hot melt adhesive film into a width of 5 mm and a length of 70 mm. The maximum stress (MPa) was measured for the test piece using Tensilon (manufactured by Shimadzu Corporation, head speed: 300 mm / min) in accordance with JIS K7311. This was defined as the normal maximum point stress.
Next, the test piece was allowed to stand at 120 ° C. for 30 days, and the maximum point stress was measured in the same manner as described above to obtain the maximum point stress after the heat resistance test.
The heat resistance was evaluated by the maximum point stress retention (%) before and after the heat test.
In addition, since the curability of the moisture curable polyurethane hot melt resin composition was poor and an adhesive could not be obtained, the heat resistance could not be evaluated, so “−” was assigned.

[Illegal evaluation of wet heat resistance]
The test piece obtained in [Method for evaluating heat resistance] was allowed to stand for 20 days under conditions of 80 ° C. and 95% RH, and then the maximum point stress was measured in the same manner as described above. did.
The wet heat resistance was evaluated by the maximum point stress retention (%) before and after the wet heat resistance test.
The moisture curable polyurethane hot melt resin composition having a poor curability and having no adhesive could not be evaluated for moisture and heat resistance, and was evaluated as “-”.

[Evaluation method of weather resistance]
The moisture-curable polyurethane hot-melt adhesive obtained in Examples and Comparative Examples was melted by heating to 110 ° C., and applied to an olefin sheet with a thickness of 50 μm using an applicator with a clearance of 50 μm heated to 110 ° C. After that, MDF was placed on the adhesive coating layer and bonded with a hand roller to obtain a laminate.
The obtained laminate was subjected to an accelerated weathering test for 1,000 hours using a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd., 83 ° C., no rain, light source carbon arc).
Thereafter, a load of 500 g was applied to the MDF of the laminated body in the 90 ° direction and left standing at 60 ° C. for 24 hours, and the peel length of the MDF was measured.
In addition, it evaluated that that whose peeling length is 5 mm or less is excellent in a weather resistance.
Moreover, since the sclerosis | hardenability of the moisture hardening type polyurethane hot-melt resin composition was unsatisfactory and the adhesive agent was not obtained, since weatherability evaluation could not be performed, it was set as "-".

“Polylite MX-2555”; aliphatic polyester polyol (reacted with 1,6-hexanediol and dodecanedioic acid), number average molecular weight: 3,800, “Polylite MX-2906” manufactured by DIC Corporation; aromatic polyester Polyol (reacted with ethylene glycol, orthophthalic acid, terephthalic acid and adipic acid), number average molecular weight: 3,600, “Duranate T-4672” manufactured by DIC; polycarbonate polyol (dimethyl carbonate, 1,6-hexanediol) And 1,4-butanediol), number average molecular weight; 2,000, “Nipporan 980R” manufactured by Asahi Kasei Chemicals; polyhexamethylene carbonate diol, number average molecular weight; 2000, manufactured by Nippon Polyurethane

It was found that the moisture curable polyurethane hot melt adhesives of Examples 1 to 5 of the present invention have good heat resistance, moist heat resistance, and weather resistance.
On the other hand, Comparative Example 1 is an embodiment that does not contain an acrylic polyol as a polyol.
It was found that heat resistance and moist heat resistance were poor, and in particular, the weather resistance of the laminate was poor. Moreover, it turned out that melt viscosity is high and coating workability | operativity is also unsatisfactory.
Moreover, although the comparative example 2 is an aspect which does not contain a polycaprolactone polyol as a polyol, it turned out that moisture sclerosis | hardenability (initial adhesiveness) is unsatisfactory.

Claims (5)

A moisture-curable polyurethane hot melt resin composition containing a urethane prepolymer having an isocyanate group obtained by reacting a polyol (A) and a polyisocyanate (B),
The polyol (A) is a number average molecular weight ranging from 1,000 to 5,000 aliphatic polyester di-ol (A-1), the aromatic polyester polyol (A-2), number average molecular weight of 20,000 Acrylic polyol (A-4) which is a polymer of polycaprolactone polyol (A-3), methyl (meth) acrylate, n-butyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate in the range of 200,000 , And polycarbonate polyol (A-5) ,
The usage-amount of the said aromatic polyester polyol (A-2) is the range of 10-60 mass parts with respect to 100 mass parts of the said aliphatic polyester diol (A-1),
The amount of the polycaprolactone polyol (A-3) used is in the range of 1 to 20 parts by mass with respect to 100 parts by mass of the aliphatic polyester diol (A-1).
The amount of the acrylic polyol (A-4) used is in the range of 20 to 50 parts by mass with respect to 100 parts by mass of the aliphatic polyester diol (A-1).
The amount of the polycarbonate polyol (A-5) is, the aliphatic polyester diol (A-1) moisture-curable polyurethane hot-melt, characterized in range der Rukoto of 5-30 parts by weight per 100 parts by weight Resin composition.
The moisture-curable polyurethane hot melt resin composition according to claim 1, wherein the urethane prepolymer has an isocyanate group content of 2.5 to 8.0%. The mass ratio [(A-3) / (A-4)] of the polycaprolactone polyol (A-3) and the acrylic polyol (A-4) is in the range of 5/95 to 50/50. 3. The moisture curable polyurethane hot melt resin composition according to 1 or 2. The moisture-curable polyurethane hot melt resin composition according to any one of claims 1 to 3, wherein the polycarbonate polyol does not have an alicyclic structure. The moisture-curable polyurethane hot melt resin composition according to any one of claims 1 to 4, further comprising a hindered amine-based antioxidant and a phenol-based antioxidant.