CN116333662A - Moisture-curing polyurethane hot-melt resin composition, adhesive and synthetic leather - Google Patents

Abstract

The problem to be solved by the present invention is to provide a moisture-curable polyurethane hot-melt resin composition excellent in adhesiveness to a thermoplastic resin layer and low-temperature flexibility. The invention provides a moisture-curing polyurethane hot-melt resin composition, which is characterized in that it contains a hot-melt urethane prepolymer (A) and a phosphoric acid ester (B) having an isocyanate group, and the hot-melt carbamic acid The ester prepolymer (A) is a polyol (a) containing 50% by mass or more of polyether polyol (a1) as a raw material, with respect to 100 parts by mass of the hot-melt urethane prepolymer (A), The content of the phosphoric acid ester (B) exceeds 0.2 parts by mass.

Description

Moisture-curing polyurethane hot-melt resin composition, adhesive and synthetic leather

technical field

The invention relates to a moisture-curing polyurethane hot-melt resin composition, adhesive and synthetic leather.

Background technique

In synthetic leather, polyurethane (PU), polyvinyl chloride (PVC), olefin-based thermoplastic elastomer (TPO), etc. are used as surface materials, and adhesives for base fabrics such as fabrics and non-woven fabrics are generally used. A bonded material (for example, refer to Patent Document 1.). Among them, for adhesives, solvent-based adhesives have been widely used so far and are generally used. However, as an environmental measure, regions, countries, and companies require the reduction of VOC. Replacement of the adhesive.

As a solvent-free adhesive, research on a polyurethane-based moisture-curing hot-melt adhesive (RHM) has been actively conducted. In the conventional solvent-based and water-based systems, a low-viscosity compound solution is applied to the skin layer, dried to remove the solvent, and aged if necessary to obtain a firm coating. It is characterized in that, since the viscosity is low, the wettability to the skin material is also good, and it is easy to obtain adhesiveness.

On the other hand, RHM uses a substance that dissolves by heat, but its viscosity is higher than that of solvent-based or water-based, and it is difficult to obtain wettability to the skin layer. Among them, for adherends such as PVC skin materials, the wettability with RHM is generally low, and even if conventional RHM is used, it is difficult to exhibit sufficient performance in terms of adhesiveness.

prior art literature

patent documents

Patent Document 1: JP 2008-514403 Gazette 2021-73135

Contents of the invention

The problem to be solved by the invention

The problem to be solved by the present invention is to provide a moisture-curable polyurethane hot-melt resin composition excellent in adhesiveness to a thermoplastic resin layer and low-temperature flexibility.

means to solve the problem

The present invention provides a moisture-curing polyurethane hot-melt resin composition, which is characterized in that it is a moisture-curing polyurethane thermal A molten resin composition, wherein the hot-melt urethane prepolymer (A) is made of polyol (a) containing 50% by mass or more of polyether polyol (a1) as a raw material, relative to the hot-melt urethane For 100 parts by mass of the ester prepolymer (A), the content of the phosphoric acid ester (B) exceeds 0.2 parts by mass.

Moreover, this invention provides the adhesive agent characterized by containing the said moisture-curable polyurethane hot-melt resin composition. In addition, the present invention provides a synthetic leather characterized by having at least a thermoplastic resin layer and an adhesive layer.

Invention effect

The moisture-curable polyurethane hot-melt resin composition of the present invention is excellent in adhesiveness to a thermoplastic resin layer and low-temperature flexibility. Therefore, the moisture-curable polyurethane hot-melt resin composition of this invention can be used especially suitably for manufacture of the synthetic leather which uses a thermoplastic resin as a surface material.

Detailed ways

The moisture-curable polyurethane hot-melt resin composition of the present invention contains a hot-melt urethane prepolymer (A) having an isocyanate group made from a specific polyol (a) as a raw material and a specific amount of phosphoric acid ester (B).

From the viewpoint of obtaining excellent low-temperature flexibility, the hot-melt urethane prepolymer (A) having isocyanate groups must be polyol (a) containing 50% by mass or more of polyether polyol (a1). For the raw material. By designing in this way, the glass transition temperature of the adhesive can be lowered, so excellent low-temperature flexibility can be obtained. The amount of the polyether polyol (a1) used is preferably 50 to 90% by mass, more preferably 55 to 70% by mass, in the polyol (a) from the viewpoint that more excellent low-temperature flexibility can be obtained. .

As the polyether polyol (a1), for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxyethylene polyoxytetramethylene glycol, , polyoxypropylene polyoxytetramethylene glycol, etc. These polyols may be used alone or in combination of two or more. Among these, polypropylene glycol and/or polytetramethylene glycol are preferable from the viewpoint of obtaining more excellent low-temperature flexibility, and polytetramethylene glycol is more preferable from the viewpoint of obtaining further superior moisture and heat resistance. .

As the polyol (a), other polyols may be used in combination in addition to the polyether polyol (a). As the other polyol, for example, commercially available polyols such as polyester polyol, polycarbonate polyol, polybutadiene polyol, silicon diol, and acrylic diol can be used. These polyols may be used alone or in combination of two or more.

The number average molecular weight of the polyol (a) is preferably from 500 to 10,000, more preferably from 1,000 to 5,000, from the viewpoint of obtaining more excellent adhesiveness, low-temperature flexibility, and mechanical strength. In addition, the number average molecular weight of the said polyol (a) shows the value measured by the gel permeation chromatography (GPC) method.

As the isocyanate group-containing hot-melt urethane prepolymer (A), for example, a reaction product with the polyol (a) and polyisocyanate (b) can be used.

As the polyisocyanate (b), for example, polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate isocyanate, phenylene diisocyanate, toluene diisocyanate can be used. , naphthalene diisocyanate and other aromatic polyisocyanates; hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate , tetramethylxylylene diisocyanate and other aliphatic or alicyclic polyisocyanates, etc. Among these, aromatic polyisocyanate is preferable, and diphenylmethane diisocyanate is more preferable from the viewpoint of obtaining more excellent reactivity and adhesiveness.

The hot-melt urethane prepolymer (A) has a polymer terminal and a molecule that can react with moisture present in the air, the substrate coated with the urethane prepolymer, and the adherend to form a Isocyanate group of cross-linked structure.

As the production method of the hot-melt urethane prepolymer (A), for example, the polyol (a) can be added dropwise to the reaction vessel containing the polyisocyanate (b) and then heated, It is manufactured by reacting the isocyanate group which the said polyisocyanate (b) has with respect to the hydroxyl group which the said polyol (a) has in excess.

From the viewpoint of obtaining more excellent hot-melt properties, adhesiveness, and low-temperature flexibility, when the polyol (a) and the polyisocyanate (b) are reacted, the polyol (a) has The molar ratio [NCO/OH] of the hydroxyl groups contained in the polyisocyanate (b) to the isocyanate groups contained in the polyisocyanate (b) is preferably 1.3 to 2.5, more preferably 1.5 to 2.0.

As the isocyanate group content (hereinafter, abbreviated as "NCO%") of the hot-melt urethane prepolymer (A), it is possible to obtain more excellent hot-melt properties, adhesiveness and low-temperature flexibility. From the aspect, it is preferably 2.0 to 5.0% by mass, and more preferably 2.5 to 3.5% by mass. In addition, NCO% of the said hot-melt urethane prepolymer (A) shows the value measured by the potentiometric titration method in accordance with JISK 1603-1:2007.

The phosphate ester (B) is an essential component for obtaining excellent adhesiveness to the thermoplastic resin layer. By adding the said phosphate ester (B), the compatibility of the interface of a thermoplastic resin and RHM improves, and excellent adhesiveness can be obtained.

As the phosphoric acid ester (B), for example, a compound represented by the following formula (1) can be used, and one type or two or more types can be used in combination.

[chemical formula 1]

(HO) _n P(O)(OR) _3-n (1)

(In formula (1), n represents 1 or 2, and R represents an alkyl group.)

As the phosphoric acid ester (B), among the compounds represented by the formula (1), R is preferably a compound having 1 to 10 carbon atoms from the viewpoint of obtaining more excellent adhesiveness to the thermoplastic resin layer, More preferably, R is a compound having 1 to 8 carbon atoms.

Moreover, in order to obtain the said effect, content of the said phosphoric acid ester (B) must exceed 0.2 mass part with respect to 100 mass parts of said hot-melt urethane prepolymers (A). The content of the phosphoric acid ester (B) is preferably 100 parts by mass of the hot-melt urethane prepolymer (A) from the viewpoint of obtaining more excellent adhesiveness to the thermoplastic resin layer. 0.2 to 1.0 parts by mass, more preferably 0.25 to 0.60 parts by mass.

The moisture-curable polyurethane hot-melt resin composition of the present invention contains the above-mentioned hot-melt urethane prepolymer (A) and the above-mentioned phosphoric acid ester (B) as essential components, but may contain other additives as necessary.

As the other additives, for example, urethanization catalysts, neutralizing agents, crosslinking agents, silane coupling agents, thickeners, fillers, thixotropy imparting agents, tackifiers, waxes, heat stabilizers can be used , light stabilizer, fluorescent whitening agent, foaming agent, pigment, dye, conductivity imparting agent, antistatic agent, moisture permeability enhancer, water repellent, oleophobic agent, hollow foam, flame retardant, water absorbing agent , Hygroscopic agent, deodorant, foam stabilizer, anti-adhesion agent, anti-hydrolysis agent, etc. These additives may be used alone or in combination of two or more. It should be noted that the moisture-curable polyurethane hot-melt resin composition of the present invention has excellent adhesiveness and low-temperature flexibility even when a foaming agent is added to form a foam.

As described above, the moisture-curable polyurethane hot-melt resin composition of the present invention is excellent in adhesiveness to a thermoplastic resin layer and low-temperature flexibility. Therefore, the moisture-curable polyurethane hot-melt resin composition of this invention can be used especially suitably for manufacture of the synthetic leather which uses a thermoplastic resin as a surface material.

Next, the synthetic leather of this invention is demonstrated.

The synthetic leather has at least a thermoplastic resin layer and an adhesive layer containing the moisture-curable polyurethane hot-melt resin composition. leather.

As the substrate, for example, materials based on polyester fiber, polyethylene fiber, nylon fiber, acrylic fiber, polyurethane fiber, acetate fiber, rayon fiber, polylactic acid fiber, cotton, hemp, silk, wool, glass, etc. can be used. Non-woven fabrics, woven fabrics, knitted fabrics, etc. of fibers, carbon fibers, and their blended fibers.

As the thermoplastic resin layer, for example, known polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride, polystyrene, TPO (Thermoplastic Olefinic Elastomer: thermoplastic polyolefin elastomer), thermoplastic ester elastomer, etc. , thermoplastic polyurethane and other resin layers. In the present invention, even in the case of using polyvinyl chloride, TPO, thermoplastic ester elastomer, thermoplastic polyurethane as the thermoplastic resin, it has excellent adhesiveness and low-temperature flexibility, especially for difficult-to-adhesive Polyvinyl chloride, whether foamed or unfoamed, has excellent adhesion and low-temperature flexibility.

The adhesive layer is formed from the moisture-curable polyurethane hot-melt resin composition of the present invention. Examples of the formation method include melting the moisture-curable polyurethane hot-melt resin composition at 100 to 140°C, Coating methods such as roll coater, spray coater, T-die coater, knife coater, comma coater; precision methods such as dispenser, inkjet printing, screen printing, offset printing, etc.; nozzle coating A method of coating on the thermoplastic resin layer or the base material, and then laminating.

In addition, after laminating the two layers with the adhesive, the adhesive may be dried and cured by a known method as necessary.

As the synthetic leather, a surface treatment layer may be further provided on the thermoplastic resin layer. As the surface treatment layer, for example, a surface treatment layer formed of known solvent-based urethane resin, water-based urethane resin, solvent-based acrylic resin, water-based acrylic resin, or the like can be used.

【Example】

Hereinafter, the present invention will be described in more detail using examples.

[Example 1]

Add polytetramethylene glycol (number average molecular weight: 2000, hereinafter abbreviated as "PEt-1") 50 parts by mass, Aromatic polyester polyol (made by reacting 1,6-hexanediol and phthalic acid, number average molecular weight: 2000, hereinafter abbreviated as "PEs-1".) 30 parts by mass, aliphatic polyester polyol 20 parts by mass of alcohol (formed by reacting 1,6-hexanediol and sebacic acid, number average molecular weight: 3500, hereinafter abbreviated as "PEs-2") were mixed, and heated at 100°C under reduced pressure , thereby dehydrating until the water content in the flask becomes 0.05% by mass or less. Next, the inside of the flask was cooled to 90° C., 23 parts by mass of 4,4′-diphenylmethane diisocyanate (hereinafter abbreviated as “MDI”) melted at 70° C. The reaction was carried out for about 3 hours until the isocyanate group content reached a constant value to obtain a hot-melt urethane prepolymer. Phosphate (a mixture of monobutyl phosphate and dibutyl phosphate, average molecular weight: 182, hereinafter abbreviated as "phosphate (1)") was blended with respect to 100 parts by mass of the hot-melt urethane prepolymer. 0.37 parts by mass to obtain a moisture-curable polyurethane hot-melt resin composition (1).

[Example 2]

Add the PEt-1 of 55 mass parts, the PEs-1 of 30 mass parts, aliphatic polyester polyol (make ethylene glycol, 1 , obtained by reacting 6-hexanediol, neopentyl glycol and adipic acid, number average molecular weight: 5500, hereinafter abbreviated as "PEs-3".) 15 parts by mass, mixed, and depressurized at 100°C Heating dehydrates until the water content in the flask becomes 0.05% by mass or less. Next, cool the inside of the flask to 90°C, add 20 parts by mass of MDI melted at 70°C, and react for about 3 hours at 110°C under a nitrogen atmosphere until the isocyanate group content becomes constant to obtain a hot-melt urethane pre- Polymer. With respect to 100 parts by mass of this hot-melt urethane prepolymer, 0.48 parts by mass of phosphoric acid ester (1) was blended to obtain a moisture-curable polyurethane hot-melt resin composition (2).

[Example 3]

Add polypropylene glycol (number-average molecular weight: 2000, hereinafter abbreviated as "PEt-2".) 55 parts by mass and 20 parts by mass of PEs in a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser - 1. 25 parts by mass of PEs-2 were mixed, and heated under reduced pressure at 100°C to dehydrate until the water content in the flask became 0.05% by mass or less. Next, cool the inside of the flask to 90°C, add 21 parts by mass of MDI melted at 70°C, and react for about 3 hours at 110°C under a nitrogen atmosphere until the isocyanate group content becomes constant to obtain a hot-melt urethane pre- Polymer. With respect to 100 parts by mass of the hot-melt urethane prepolymer, 0.30 parts by mass of the phosphoric acid ester (1) was blended to obtain a moisture-curable polyurethane hot-melt resin composition (3).

[Example 4]

Add the PEt-1 of 60 mass parts, the PEs-1 of 25 mass parts, the PEs-2 of 15 mass parts in the four-necked flask that possesses thermometer, stirrer, inert gas inlet and reflux condenser, mix, at 100 °C, dehydration was performed by heating under reduced pressure until the water content in the flask became 0.05% by mass or less. Next, cool the inside of the flask to 90°C, add 22 parts by mass of MDI melted at 70°C, and react for about 3 hours at 110°C under a nitrogen atmosphere until the isocyanate group content becomes constant to obtain a hot-melt urethane pre- Polymer. 0.37 parts by mass of phosphoric acid ester (1) was blended with respect to 100 parts by mass of the hot-melt urethane prepolymer to obtain a moisture-curable polyurethane hot-melt resin composition (4).

[Example 5]

Add the PEt-2 of 65 mass parts, the PEs-1 of 25 mass parts, the PEs-2 of 15 mass parts in the four-necked flask that possesses thermometer, stirrer, inert gas inlet and reflux condenser, mix, at 100 °C, dehydration was performed by heating under reduced pressure until the water content in the flask became 0.05% by mass or less. Next, cool the inside of the flask to 90°C, add 24 parts by mass of MDI melted at 70°C, and react for about 3 hours at 110°C under a nitrogen atmosphere until the isocyanate group content becomes constant to obtain a hot-melt urethane pre- Polymer. With respect to 100 parts by mass of the hot-melt urethane prepolymer, 0.52 parts by mass of the phosphoric acid ester (1) was blended to obtain a moisture-curable polyurethane hot-melt resin composition (5).

[Example 6]

Add the PEt-1 of 65 mass parts, the PEs-1 of 15 mass parts, the PEs-3 of 20 mass parts in the four-necked flask that possesses thermometer, stirrer, inert gas inlet and reflux condenser, mix, at 100 °C, dehydration was performed by heating under reduced pressure until the water content in the flask became 0.05% by mass or less. Next, cool the inside of the flask to 90°C, add 21 parts by mass of MDI melted at 70°C, and react for about 3 hours at 110°C under a nitrogen atmosphere until the isocyanate group content becomes constant to obtain a hot-melt urethane pre- Polymer. 0.30 parts by mass of phosphoric acid ester (1) was blended with respect to 100 parts by mass of the hot-melt urethane prepolymer to obtain a moisture-curable polyurethane hot-melt resin composition (6).

[Example 7]

Add 30 parts by mass of PEt-1, 30 parts by mass of PEt-2, 20 parts by mass of PEs-1, and 20 parts by mass of PEs in a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser -2. Mix and heat under reduced pressure at 100° C., thereby dehydrating until the water content in the flask becomes 0.05% by mass or less. Next, cool the inside of the flask to 90°C, add 22 parts by mass of MDI melted at 70°C, and react for about 3 hours at 110°C under a nitrogen atmosphere until the isocyanate group content becomes constant to obtain a hot-melt urethane pre- Polymer. With respect to 100 parts by mass of the hot-melt urethane prepolymer, 0.36 parts by mass of the phosphoric acid ester (1) was blended to obtain a moisture-curable polyurethane hot-melt resin composition (7).

[Comparative example 1]

Add the PEt-1 of 55 mass parts, the PEs-1 of 20 mass parts, the PEs-2 of 15 mass parts in the four-necked flask that possesses thermometer, stirrer, inert gas inlet and reflux condenser, mix, at 100 °C, dehydration was performed by heating under reduced pressure until the water content in the flask became 0.05% by mass or less. Next, cool the inside of the flask to 90°C, add 20 parts by mass of MDI melted at 70°C, and react for about 3 hours at 110°C under a nitrogen atmosphere until the isocyanate group content becomes constant to obtain a hot-melt urethane pre- Polymer. With respect to 100 parts by mass of the hot-melt urethane prepolymer, 0.11 parts by mass of the phosphoric acid ester (1) was blended to obtain a moisture-curable polyurethane hot-melt resin composition (R1).

[Comparative example 2]

Add the PEt-1 of 60 mass parts, the PEs-1 of 25 mass parts, the PEs-2 of 15 mass parts in the four-necked flask that possesses thermometer, stirrer, inert gas inlet and reflux condenser, mix, at 100 °C, dehydration was performed by heating under reduced pressure until the water content in the flask became 0.05% by mass or less. Next, cool the inside of the flask to 90°C, add 22 parts by mass of MDI melted at 70°C, and react for about 3 hours at 110°C under a nitrogen atmosphere until the isocyanate group content becomes constant to obtain a hot-melt urethane pre- Polymer. With respect to 100 parts by mass of the hot-melt urethane prepolymer, 0.06 parts by mass of the phosphoric acid ester (1) was blended to obtain a moisture-curable polyurethane hot-melt resin composition (R2).

[Comparative example 3]

Add 35 mass parts of PEt-1, 35 mass parts of PEs-1, 30 mass parts of PEs-3 in a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, mix, and mix at 100 °C, dehydration was performed by heating under reduced pressure until the water content in the flask became 0.05% by mass or less. Next, cool the inside of the flask to 90°C, add 19 parts by mass of MDI melted at 70°C, and react for about 3 hours at 110°C under a nitrogen atmosphere until the isocyanate group content becomes constant to obtain a hot-melt urethane pre- polymer to obtain a moisture-curable polyurethane hot-melt resin composition (R3).

[Comparative example 4]

Add the PEt-1 of 30 mass parts, the PEs-1 of 45 mass parts, the PEs-3 of 25 mass parts in the four-necked flask that possesses thermometer, stirrer, inert gas inlet and reflux condenser, mix, at 100 °C, dehydration was performed by heating under reduced pressure until the water content in the flask became 0.05% by mass or less. Next, cool the inside of the flask to 90°C, add 20 parts by mass of MDI melted at 70°C, and react for about 3 hours at 110°C under a nitrogen atmosphere until the isocyanate group content becomes constant to obtain a hot-melt urethane pre- Polymer. With respect to 100 parts by mass of the hot-melt urethane prepolymer, 0.36 parts by mass of the phosphoric acid ester (1) was blended to obtain a moisture-curable polyurethane hot-melt resin composition (R4).

[Measurement method of number average molecular weight and weight average molecular weight]

The number average molecular weight of the polyhydric alcohol used in the Example and the comparative example shows the value measured by the gel permeation column chromatography (GPC) method under the following conditions.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)

Column: The following columns manufactured by Tosoh Corporation were connected in series and used.

"TSKgel G5000" (7.8mmI.D.×30cm)×1

"TSKgel G4000" (7.8mmI.D.×30cm)×1

"TSKgel G3000" (7.8mmI.D.×30cm)×1

"TSKgel G2000" (7.8mmI.D.×30cm)×1

Detector: RI (differential refractometer)

Column temperature: 40°C

Eluent: Tetrahydrofuran (THF)

Flow rate: 1.0mL/min

Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)

Standard sample: A standard curve was prepared using the following standard polystyrene.

(standard 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

[How to make synthetic leather]

In a constant temperature and constant humidity room adjusted to a temperature of 23°C and a humidity of 50±5%, the polyvinyl chloride sheet was intermittently coated with 40±5 g/m ² of the products obtained in Examples and Comparative Examples using a gravure coater. Moisture-curable polyurethane hot-melt resin composition, the resultant is laminated with a polyester base, and the resultant is aged at a temperature of 23°C and a humidity of 50±5% for 24 hours to obtain a synthetic leather.

[Evaluation method of adhesiveness]

For each of the obtained synthetic leathers, using Tensilon (Tensilon universal testing machine "RTC-1210A" manufactured by Orientec Co., Ltd.), the peeling strength was measured under the condition of crosshead measurement: 200mm/min, and the adhesive strength was measured. 6N/cm The above evaluation was "◯", and less than 6 N/cm was evaluated as "×".

[Evaluation method of low temperature bendability]

Each of the obtained synthetic leathers was subjected to a bending test (-10°C, 100 times/minute) using a flexometer, and the number of times until cracks occurred on the surface of the synthetic leather was measured, and 20,000 times or more were evaluated as "○", and less than 20,000 times were evaluated. 20,000 evaluations are "×".

【Table 1】

【Table 2】

【table 3】

The numbers in Tables 1 to 3 represent parts by mass. In addition, the compounding quantity of a phosphate ester (B) shows the mass parts with respect to 100 mass parts of hot-melt urethane prepolymers (A).

It can be seen that Examples 1 to 7, which are the moisture-curable polyurethane hot-melt resin compositions of the present invention, are excellent in adhesiveness to polyvinyl chloride and low-temperature flexibility.

On the other hand, in Comparative Examples 1 and 2, the content of the phosphoric acid ester (B) was lower than the range prescribed in the present invention, and the adhesiveness was poor.

In Comparative Example 3, the amount of polyether polyol (a1) used was less than the range specified in the present invention, and the phosphoric acid ester (B) was not used, and the adhesiveness and low-temperature flexibility were poor.

In Comparative Example 4, the usage-amount of polyether polyol (a1) was less than the range prescribed|regulated by this invention, and low-temperature flexibility was unsatisfactory.

Claims (3)

1. A moisture-curable polyurethane hot-melt resin composition comprising a hot-melt urethane prepolymer (A) having isocyanate groups and a phosphoric acid ester (B),

the hot-melt urethane prepolymer (A) is produced from a polyol (a) containing 50 mass% or more of a polyether polyol (a 1),

the content of the phosphoric acid ester (B) exceeds 0.2 parts by mass with respect to 100 parts by mass of the hot-melt urethane prepolymer (a).

2. An adhesive comprising the moisture-curable polyurethane hot-melt resin composition according to claim 1.

3. A synthetic leather comprising at least a thermoplastic resin layer and an adhesive layer containing the moisture-curable polyurethane hot-melt resin composition according to claim 1.