TWI907581B - Moisture-curing polyurethane resin compositions, adhesives, and laminates - Google Patents

Abstract

The problem this invention aims to solve is to provide a moisture-curing polyurethane resin composition with excellent adhesion and washability to fabrics (especially water-repellent fabrics). The solution of this invention is to provide a moisture-curing polyurethane hot-melt resin composition, which is a moisture-curing polyurethane hot-melt resin composition containing an isocyanate-based urethane prepolymer (i), wherein the isocyanate-based urethane prepolymer (i) is a reaction product of a polyol (A) and a polyisocyanate (B); characterized in that the aforementioned polyol (A) contains a compound (a1) represented by the following general formula (1). The amount of the aforementioned compound (a1) used in the polyol (A) is preferably in the range of 0.5% to 30% by mass. The aforementioned polyol (A) preferably further contains polyester polyol and/or polyether polyol.

Description

Moisture-curing polyurethane resin compositions, adhesives, and laminates

This invention relates to a moisture-curing polyurethane resin composition, an adhesive, and a laminate.

Breathable and waterproof functional clothing is a structure in which a breathable membrane is bonded to a fabric using an adhesive. From the perspective of achieving good adhesion between the breathable membrane and the fabric, urethane-based adhesives are generally used as such. Furthermore, among the aforementioned urethane-based adhesives, considering recent global restrictions on solvent discharge or residual solvents, the use of solvent-free moisture-curing polyurethane resin compositions is gradually increasing (see, for example, Patent 1).

On the other hand, the fabrics used, designed for lightweighting and high performance, have improved denier and water repellency. However, this has led to a decrease in adhesion between the pre-treated water-repellent fabric and the adhesive. Furthermore, current moisture-curing polyurethane resin compositions have not demonstrated high adhesion, especially for ultra-water-repellent fabrics. [Previous Art Documents] [Patent Documents]

Patent Document 1: Japanese Patent Application Publication No. 2017-202608

[The problem the invention aims to solve]

The problem this invention aims to solve is to provide a moisture-curing polyurethane resin composition with excellent adhesion to fabrics (especially water-repellent fabrics) and washability. [Means for solving the problem]

The present invention is a moisture-curing polyurethane hot melt resin composition, which is a moisture-curing polyurethane hot melt resin composition containing an isocyanate group-containing urethane prepolymer (i), wherein the isocyanate group-containing urethane prepolymer (i) is a reaction product of a polyol (A) and a polyisocyanate (B); characterized in that the aforementioned polyol (A) contains a compound (a1) represented by the following general formula (1). (In formula (1), _R1 and _R2 each represent alkyl groups with 1 to 6 carbon atoms, m and n represent integers with a total of 10 to 40, and a represents integers with a total of 5 to 30.)

Furthermore, the present invention provides an adhesive characterized by containing the aforementioned moisture-curing polyurethane resin composition. Moreover, the present invention provides a laminate characterized by having at least a fabric (i) and a cured product comprising the aforementioned moisture-curing polyurethane resin composition. [Effects of the Invention]

The moisture-curing polyurethane hot-melt resin composition of this invention is solvent-free and environmentally friendly. Furthermore, the moisture-curing polyurethane hot-melt resin composition of this invention exhibits excellent adhesion to a wide variety of fabrics, including water-repellent fabrics, and also possesses excellent wash resistance.

[The form in which the invention is implemented]

The moisture-curing polyurethane hot melt resin composition used in this invention is a reaction product of a polyol (A) containing a specific compound and a polyisocyanate (B), and contains a polyurethane prepolymer (i) having an isocyanate group.

The aforementioned polyol (A) must contain the compound (a1) of the aforementioned general formula (1) to obtain excellent adhesion and washability to fabrics (especially water-repellent fabrics).

Regarding the aforementioned polyol (A), it is believed that by introducing compounds such as the aforementioned compound (a1) which have hydroxyl groups at both ends and have polysiloxane chains and long-chain alkyl groups, the permeability (affinity) to water-repellent fabrics can be improved, and excellent adhesion and washability can be exhibited.

As for the aforementioned compound (a1), from the viewpoint of obtaining superior adhesion and washability, _R1 is preferably an alkyl group having 1 to 2 carbon atoms, more preferably an ethyl group. Also, _R2 is preferably an alkyl group having 3 to 6 carbon atoms, more preferably an propyl group. Furthermore, m is preferably an integer from 5 to 20, more preferably an integer from 5 to 15; n is preferably an integer from 0 to 40, more preferably an integer from 0 to 20. Also, a is preferably an integer from 5 to 30, more preferably an integer from 10 to 20.

From the viewpoint of obtaining better adhesion and washability, the amount of the aforementioned compound (a1) used in the polyol (A) is preferably 0.5 to 30% by mass, and more preferably 1.0 to 15% by mass.

As the aforementioned polyol (A), other polyols besides the aforementioned compound (a1) may also be used. Examples of such other polyols include polyester polyols, polyether polyols, polycarbonate polyols, and polyacrylic acid polyols. These polyols may be used alone or in combination of two or more. Among these, polyester polyols and/or polyether polyols are preferred from the viewpoint of obtaining superior mechanical strength, etc.

As the aforementioned polyester polyol, for example, the reaction product of a polyacid and a compound having two or more hydroxyl groups can be used.

As the aforementioned polyacids, examples include: oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanoic acid, glutaric acid, pimelic acid, octanoic acid, dimer acid, sebacic acid, undecanedicarboxylic acid, hexahydroterephthalic acid, and phthalic acid compounds (phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid). These polyacids can be used alone or in combination of two or more. Among these, adipic acid and/or phthalic acid compounds are preferred from the viewpoint of obtaining superior adhesion and mechanical strength.

As the reaction product of the aforementioned compounds having two or more components, examples such as: ethylene glycol, diethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, pentanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, hexanediol, neopentanediol, hexamethylene glycol, glycerol, trimethylolpropane, bisphenol A or bisphenol F, and their epoxide adducts, 2-methyl-1,3-propanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,2,4- Trimethyl-1,3-pentanediol, 1,2-butanediol, 1,3-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, neopentanediol, 2-isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, 2-methyl-1,8-octanediol, neopentanediol, trihydroxymethylpropane, etc. These compounds can be used alone or in combination of two or more.

From the viewpoint of obtaining superior adhesion and mechanical strength, the number average molecular weight of the aforementioned polyester polyol is preferably 500 to 10,000, and more preferably 700 to 5,000. Furthermore, the aforementioned number average molecular weight of the polyester polyol is a value determined by gel osmosis chromatography (GPC).

From the viewpoint of obtaining better mechanical strength, the amount of the aforementioned polyester polyol used is preferably 10 to 100% by mass in polyol (A), and more preferably 30 to 100% by mass.

As the aforementioned polyether polyol, examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These can be used alone or in combination of two or more. Among these, polypropylene glycol is preferred from the viewpoint of obtaining superior adhesion and mechanical strength.

From the viewpoint of obtaining superior adhesion and mechanical strength, the number average molecular weight of the aforementioned polyether polyol is preferably 500 to 10,000, and more preferably 700 to 5,000. Furthermore, the aforementioned number average molecular weight of the polyether polyol is a value determined by gel osmosis chromatography (GPC).

From the viewpoint of obtaining superior mechanical strength, the amount of polyol (A) used when using the aforementioned polyether polyol is preferably 0 to 90% by mass, and more preferably 0 to 70% by mass.

As for the aforementioned polyisocyanate (B), aromatic polyisocyanates such as polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate isocyanate, phenyl dimethyl diisocyanate, phenyl diisocyanate, toluene diisocyanate, and naphthalene diisocyanate can be used; aliphatic or alicyclic polyisocyanates such as hexamethylene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylphenyl dimethyl diisocyanate can also be used. These polyisocyanates can be used alone or in combination of two or more. Of these, from the viewpoint of obtaining superior reactivity and adhesion to fabrics, aromatic polyisocyanates are preferred, and diphenylmethane diisocyanates are even more preferred.

As for the amount of polyisocyanate (B) used, the total mass of the raw materials constituting the carbamate prepolymer (i) is preferably 5 to 40% by mass, more preferably 10 to 30% by mass.

The aforementioned hot-melt urethane prepolymer (i) is obtained by reacting the aforementioned polyol (A) with the aforementioned polyisocyanate (B), and has isocyanate groups that can react with moisture present in the air or in a substrate coated with a moisture-curing hot-melt urethane resin composition to form a crosslinked structure.

As a method for manufacturing the aforementioned hot-melt urethane prepolymer (i), it can be manufactured, for example, by adding the aforementioned polyisocyanate (B) to a reaction vessel containing the aforementioned polyol (A), and allowing it to react under the condition that the isocyanate groups of the aforementioned polyisocyanate (B) are in excess relative to the hydroxyl groups of the aforementioned polyol (A).

From the viewpoint of obtaining better adhesion to fabric, the equivalent ratio (isocyanate group/hydroxyl group) of the aforementioned polyisocyanate (B) to the aforementioned polyol (A) during the manufacture of the aforementioned hot melt amino carbamate prepolymer (i) is preferably 1.1 to 5, and more preferably 1.5 to 3.0.

The isocyanate group content (hereinafter referred to as "NCO%)" of the hot-melt urethane prepolymer (i) obtained by the above method is preferably in the range of 1.7 to 5, and more preferably 1.8 to 3.0, from the viewpoint of obtaining better adhesion. Furthermore, the NCO% of the aforementioned hot-melt urethane prepolymer (i) is a value determined by potentiometric titration according to JIS K1603-1:2007.

The moisture-curing polyurethane hot melt resin composition used in this invention contains the aforementioned polyurethane prepolymer (i) as an essential component, but other additives may be used as needed.

Other additives mentioned above may include: light stabilizers, hardening catalysts, adhesives, plasticizers, stabilizers, fillers, dyes, pigments, fluorescent whitening agents, silane coupling agents, waxes, thermoplastic resins, etc. These additives may be used alone or in combination of two or more.

The moisture-curing polyurethane hot-melt resin composition of the present invention is solvent-free and is an environmentally friendly material. Furthermore, the moisture-curing polyurethane hot-melt resin composition of the present invention exhibits excellent adhesion to a wide variety of fabrics, including water-repellent fabrics, and also possesses excellent wash resistance.

Next, the multilayer of the present invention will be described.

The laminate of the present invention is a cured body having at least a fabric (i) and the aforementioned moisture-curing polyurethane hot melt resin composition.

As for the aforementioned fabric (i), for example, the following fiber base materials may be used: non-woven fabrics, woven fabrics, woven fabrics, etc., made of polyester fibers, polyethylene fibers, nylon fibers, acrylic fibers, polyurethane fibers, acetate fibers, rayon fibers, polylactic acid fibers, cotton, linen, silk, wool, glass fibers, carbon fibers, and blends thereof; non-woven fabrics impregnated with polyurethane resins or the like; non-woven fabrics further provided with a porous layer; resin base materials, etc.

Furthermore, this invention exhibits excellent adhesion even when the aforementioned fabric (i) is subjected to water-repellent treatment (hereinafter referred to as "water-repellent fabric"). Moreover, in this invention, "water-repellent" in the aforementioned water-repellent fabric means that the surface free energy obtained by the following calculation is 50 mJ/ ^m² or less.

The contact angle of the measuring solution (water and diiodomethane) on the aforementioned fabric (i) was measured using a contact angle meter (DM500, manufactured by Kyowa Interface Science Co., Ltd.). Based on the result, the surface free energy of the fabric (i) was calculated using the following equation (1): (1＋cosA)・γL/2＝(γsd・γLd)1/2＋(γsp・γLp)1/2

A: Contact angle of the measuring liquid on fabric (i) γL: Surface tension of the measuring liquid γLd: Dispersion force component of the surface free energy of the measuring liquid γLp: Polar force component of the surface free energy of the measuring liquid γsd: Dispersion force component of the surface free energy of fabric (i) γsp: Polar force component of the surface free energy of fabric (i)

Methods for applying the aforementioned moisture-curing polyurethane hot melt resin composition include, for example, using a roller coater, a knife coater, a spray coater, a gravure roller coater, a corner-cutting wheel coater, a T-die coater, a smearer, a dispenser, etc.

After applying the aforementioned moisture-curing polyurethane hot melt resin composition, it can be dried and maintained using known methods.

The thickness of the cured material, which is the aforementioned moisture-curing carbamate hot melt resin composition, is, for example, in the range of 5 to 300 μm.

Furthermore, when the moisture-curing polyurethane hot-melt resin composition of the present invention is used as an adhesive for breathable and waterproof functional clothing, it is preferable that the aforementioned moisture-curing polyurethane hot-melt resin composition is applied intermittently using a gravure roller coating machine and a distributor, and then bonded to the fabric (i) and a known breathable film. The thickness of the cured product of the aforementioned moisture-curing polyurethane hot-melt resin composition in this case is, for example, in the range of 5 to 50 μm.

On top of the aforementioned moisture-permeable film, a moisture-curing polyurethane hot-melt resin composition can be further bonded to the mesh fabric via intermittent coating. [Example]

The invention is illustrated in more detail below using examples.

[Example 1] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser, 495 parts by weight of polyester polyol 1 (which reacts with adipic acid and 2-methyl-1,3-propanediol, with an average molecular weight of 2,000) and 495 parts by weight of polyester polyol 2 (which reacts with phthalic anhydride, diethylene glycol, and neopentyl glycol, with an average molecular weight of 1,000) were added. 10 parts by weight of a compound (hereinafter referred to as "a1-1") of which ₁ represents ethyl, m represents 20, n represents 0, and a represents 15 are subjected to depressurization drying at 110°C and dehydrated until the water content is less than 0.05% by weight. Then, after cooling to 60°C, 331 parts by weight of diphenylmethane diisocyanate (hereinafter referred to as "MDI") are added, and the temperature is raised to 110°C and reacted for 2 hours until the isocyanate group content becomes constant, thereby obtaining a urethane prepolymer (1) and preparing a moisture-curing polyurethane hot melt resin composition (1).

[Example 2] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser, 150 parts by weight of polyester polyol 3 (the reactant of 1,6-hexanediol and phthalic anhydride, with a quantity average molecular weight of 2,000), 700 parts by weight of polyester polyol 4 (the reactant of phthalic anhydride, adipic acid, terephthalic acid, and ethylene glycol, with a quantity average molecular weight of 3,500), and 30 parts by weight of a compound in formula (1) where _R1 represents ethylenyl, m represents 15, n represents 5, and a represents 15 (hereinafter referred to as "a1-2") were added. The mixture was dried under reduced pressure at 110°C and dehydrated until the water content was below 0.05% by weight. Then, after cooling to 60°C, MDI was added. 200 parts by weight are heated to 110°C and reacted for 2 hours until the isocyanate group content becomes constant, thereby obtaining a urethane prepolymer (2) and producing a moisture-curing polyurethane hot melt resin composition (2).

[Example 3] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser, 295 parts by mass of polypropylene glycol 1 (number average molecular weight: 400), 295 parts by mass of polypropylene glycol 2 (number average molecular weight: 1,000), and 30 parts by mass of a compound in formula (1) where _R1 represents ethyl, m represents 10, n represents 10, and a represents 15 (hereinafter referred to as "a1-3") were added. The mixture was dried under reduced pressure at 110°C and dehydrated until the water content was below 0.05% by mass. Then, after cooling to 60°C, MDI was added. 459 parts by weight, heated to 110°C, reacted for 2 hours until the isocyanate group content became constant, thereby obtaining a urethane prepolymer (3), and thus producing a moisture-curing polyurethane hot melt resin composition (3).

[Comparative Example 1] In a four-necked flask equipped with a thermometer, stirrer, inert gas inlet, and reflux condenser, 495 parts by weight of polyester polyol 1 (reacting adipic acid and 2-methyl-1,3-propanediol, with a quantity average molecular weight of 2,000) and 495 parts by weight of polyester polyol 2 (reacting phthalic anhydride, diethylene glycol, and neopentyl glycol, with a quantity average molecular weight of 1,000) were added, and the reaction was carried out at 110°C. The material is depressurized and dried, and dehydrated until the moisture content is below 0.05% by mass. Then, after cooling to 60°C, 331 parts by mass of diphenylmethane diisocyanate (hereinafter referred to as "MDI") are added, and the temperature is raised to 110°C. The reaction is carried out for 2 hours until the isocyanate group content becomes constant, thereby obtaining a urethane prepolymer (R1), which is used to prepare a moisture-curing polyurethane hot-melt resin composition (R1).

[Method for Determination of Number Average Molecular Weight] The number average molecular weight of the polyols used in the Examples and Comparative Examples is expressed as a value determined by gel osmosis chromatography (GPC) under the following conditions.

Measurement Equipment: High-speed GPC device (Tosoh Corporation "HLC-8220GPC") Series: The following series of columns manufactured by Tosoh Corporation are used in series. 1 tube of "TSKgel G5000" (7.8mm I.D. × 30cm) 1 tube of "TSKgel G4000" (7.8mm I.D. × 30cm) 1 tube of "TSKgel G3000" (7.8mm I.D. × 30cm) 1 tube of "TSKgel G2000" (7.8mm I.D. × 30cm) Detector: RI (Differential Refractometer) Column Temperature: 40℃ Extraction Solution: Tetrahydrofuran (THF) Flow Rate: 1.0 mL/min Injection Volume: 100 μL (0.4% by mass tetrahydrofuran solution) Standard Sample: Use the following standard polystyrene to create the calibration curve.

(Standard Polystyrene) Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene A-500" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene A-1000" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene A-2500" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene A-5000" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene F-1" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene F-2" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene F-4" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene F-10" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene F-20" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene F-40" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene F-80" Tosoh Co., Ltd. manufactures "TSKgel Standard Polystyrene" "F-128" "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Co., Ltd.

[Method for manufacturing the laminate] First, a mixture of solvent-based polyurethane resin "CRISVON S-525 (manufactured by DIC Corporation)," methyl ethyl ketone, and dimethylformamide is uniformly coated onto release paper using a knife coating machine at a coating amount of 100 g/ ^m² (wet coating). The coating is then dried at 70°C for 1 minute, followed by drying at 120°C for 2 minutes to produce a 15 μm thick moisture-permeable polyurethane film. Next, the moisture-curing polyurethane resin compositions (1) to (3) and (R1) that were heated and melted at 120°C were intermittently coated on the above-mentioned moisture-permeable polyurethane film ¹ with a grid-shaped gravure roller heated to 120°C. After coating, they were bonded to a 40 denier water-treated nylon taffeta filament substrate and placed in an environment of 23°C and 65% relative humidity for 3 days to produce a laminate.

[Evaluation Method for Adhesion to Fabrics] On the water-permeable polyurethane film side of the resulting laminate, a 1-inch wide hot-melt adhesive tape was bonded at 130°C for 5 seconds. Following JIS K6854-2, the normal adhesion strength was measured using an "Autograph AG-1" (test head speed: 200 mm/min) manufactured by Shimadzu Corporation at a temperature of 23°C and a relative humidity of 50%. A strength of 6.0 N/inch or higher was considered to indicate excellent adhesion to water-repellent fabrics.

[Evaluation Method for Washability] The obtained laminate was washed 50 times with water according to JIS L 1089-1970, and its appearance after washing was evaluated. Furthermore, the appearance was evaluated visually according to the following criteria: "○": No peeling at all. "×": Peeling occurs on more than half of the surface area.

[Table 1] Table 1 Implementation Example 1 Implementation Example 2 Implementation Example 3 Comparative example 1 Moisture-curing polyurethane hot melt resin composition (1) (2) (3) (R1) Compound (a1) (a1-1) (a1-2) (a1-3) without Amount (mass %) of compound (a1) used in polyol (A) 0.75 2.77 2.78 0 Adhesion (N/inch) 10.0 8.0 7.5 4.0 Washability ○ ○ ○ ×

It can be seen that the moisture-curing polyurethane hot melt resin composition of the present invention has excellent adhesion to water-repellent fabrics and excellent washability.

On the other hand, Comparative Example 1 was a sample without the use of compound (a1), but it was unsatisfactory in terms of adhesion and washability of the water-repellent fabric.

without.

without.

without.

Claims (6)

A moisture-curing polyurethane hot melt resin composition comprising a moisture-curing polyurethane hot melt resin composition containing an isocyanate group-containing urethane prepolymer (i), wherein the isocyanate group-containing urethane prepolymer (i) is a reaction product of a polyol (A) and a polyisocyanate (B); characterized in that: the polyol (A) contains a compound (a1) of the following general formula (1) and one or more polyols selected from polyester polyols, polyether polyols, polycarbonate polyols, and polyacrylic acid polyols, wherein the amount of the compound (a1) in the polyol (A) is in the range of 0.5% to 15% by mass; (In formula (1), _R1 and _R2 each represent alkyl groups with 1 to 6 carbon atoms, m and n represent integers with a total of 10 to 40, and a represents integers with a total of 5 to 30). As in claim 1, a moisture-curing polyurethane hot-melt resin composition, wherein the polyol (A) comprises a polyether polyol. For example, in claim 2, the moisture-curing polyurethane hot-melt resin composition, wherein the polyether polyol is polypropylene glycol. An adhesive characterized by comprising a moisture-curing polyurethane hot-melt resin composition as described in any of claims 1 to 3. A laminate characterized as a cured body comprising at least a fabric (i) and a moisture-curing polyurethane hot-melt resin composition as claimed in any of claims 1 to 3. For example, in the laminate of claim 5, the fabric (i) is a water-repellent fabric.