TW202342684A - Urethane prepolymer composition, moisture-curable adhesive, multilayer body and synthetic artificial leather - Google Patents

Abstract

The present invention provides a urethane prepolymer composition which has excellent storage stability and is capable of forming a cured product layer that exhibits excellent flexibility, heat resistance and solvent resistance. This urethane prepolymer composition contains a urethane prepolymer (C) that is a reaction product of a polyol (A) and a polyisocyanate (B), and a trimethylolpropane adduct (D) of tolylene diisocyanate; the polyol (A) contains 5-90% by mass of a polyester polyol (A-1) that has a constituent unit derived from an aromatic dicarboxylic acid; the content of the trimethylolpropane adduct (D) of tolylene diisocyanate relative to 100 parts by mass of the urethane prepolymer (C) is 0.2-25 parts by mass; and the isocyanate group content ratio based on the sum of the urethane prepolymer (C) and the trimethylolpropane adduct (D) of tolylene diisocyanate is 1.0-6.0% by mass.

Description

Urethane prepolymer compositions, moisture-hardening adhesives, laminates and synthetic leather

The present invention relates to a urethane prepolymer composition, a moisture-hardening adhesive, a laminate and a synthetic leather.

Urethane prepolymers are used in adhesives, coatings and sealing materials. Among them, moisture-hardening urethane prepolymer has the advantage of being used in one liquid because it hardens due to moisture in the air. This kind of urethane prepolymer has functional groups such as isocyanate groups (NCO groups) in the molecule that can react with water (moisture) present in the air or in the coated substrate to form a cross-linked structure. of compounds. The urethane prepolymer is not hardened and is liquid or solid at room temperature, and various types have been developed depending on the application.

For example, a moisture-curable hot-melt composition containing a urethane prepolymer having a polyol structure derived from a polyester polyol and a polyfunctional isocyanate such as polymerized MDI has been proposed (Patent Document 1) . Furthermore, a reactive adhesive containing a urethane prepolymer having a structure derived from a polyol such as polyether polyol and a polyisocyanate such as an HDI trimer has been proposed (Patent Document 2). Furthermore, a moisture-curable adhesive composition containing a urethane prepolymer and polymerized MDI has been proposed (Patent Document 3). [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 6836713 [Patent Document 2] Japanese Patent Publication No. 2003-515636 [Patent Document 3] Japanese Patent Application Publication No. 2005-75877

(The problem that the invention wants to solve)

However, as an adhesive when manufacturing synthetic leather such as artificial leather or synthetic leather, urethane prepolymer can also be used. Synthetic leather is used as a material for the manufacture of shoes, clothing, bags, furniture, and automotive interior materials (for example, dashboards, doors, consoles, seats) and other products. Synthetic leather is usually a laminate in which a skin layer, an adhesive layer (hardened material layer) and a base material layer are laminated in order, and the hardened material layer is formed by various urethane prepolymers. In addition to good flexibility, the hardened material layer of the synthetic leather used in the above-mentioned various products is required to have heat resistance that can withstand the heat during manufacturing processing.

However, the hardened material layer formed by hardening the conventional adhesives proposed in Patent Documents 1 to 3, etc. cannot be said to be well-balanced and excellent in flexibility and heat resistance. In addition, it is known that the viscosity of the above-mentioned adhesives easily changes during storage, so the storage stability cannot be said to be good, and the solvent resistance of the formed hardened material layer also has room for improvement.

The present invention was completed in view of the problems associated with this conventional technology, and its object is to provide a urethane prepolymer composition that has excellent storage stability and can develop flexibility, heat resistance and resistance to heat. A hardened material layer with excellent solvent properties; and a moisture-hardening adhesive using the urethane prepolymer composition. Furthermore, an object of the present invention is to provide a laminated body and synthetic leather using the above-mentioned urethane prepolymer composition. (Technical means to solve problems)

That is, according to the present invention, the urethane prepolymer composition shown below is provided. [1] A urethane prepolymer composition containing: a urethane prepolymer (C) that is a reaction product of a polyol (A) and a polyisocyanate (B), and toluene diisocyanate trimethylolpropane adduct (D); and the polyol (A) contains 5 to 90 mass % of polyester polyol (A-1) having a structural unit derived from an aromatic dicarboxylic acid. ; Relative to 100 parts by mass of the aforementioned urethane prepolymer (C), the content of the trimethylolpropane adduct (D) of the aforementioned toluene diisocyanate is 0.2 to 25 parts by mass; with the aforementioned urethane acid The isocyanate group content rate based on the total of the ethyl ester prepolymer (C) and the trimethylolpropane adduct of the toluene diisocyanate (D) is 1.0 to 6.0 mass%; the polyol (A) further contains At least one other polyol (A-2) selected from the group consisting of polyester polyol (excluding the aforementioned polyester polyol (A-1)), polyether polyol, and polycarbonate polyol; In the aforementioned polyol (A), the proportion of the aforementioned other polyol (A-2) is 10 to 95% by mass. [2] The urethane prepolymer composition according to the above [1], except that the urethane prepolymer (C) is a resin having a carboxyl group or a sulfamic acid (salt) group. . [3] The urethane prepolymer composition according to the above [1] or [2], wherein the proportion of the above polyester polyol (A-1) in the above polyol (A) is 5 ~70 mass%; in the aforementioned polyol (A), the proportion of the aforementioned other polyol (A-2) is 30 to 95 mass%. [4] The urethane prepolymer composition according to any one of [1] to [3] above, wherein the molar ratio of the polyol (A) to the polyisocyanate (B) is ( NCO group/OH group) is 1.3~2.0. [5] The urethane prepolymer composition according to any one of [1] to [4] above, wherein the urethane prepolymer (C) melts at 100°C The viscosity is 110 dPa·s or less.

Furthermore, according to the present invention, the following moisture-curable adhesive, laminate and synthetic leather are provided. [6] A moisture-curing adhesive containing the urethane prepolymer composition according to any one of the above [1] to [5]. [7] A laminated body comprising: a base material; and a hardened material layer provided on the base material and formed of a hardened material of the moisture-curable adhesive described in [6]. [8] A synthetic leather comprising: a skin layer; a hardened material layer provided on the skin layer and formed of a hardened material of the moisture-hardening adhesive described in [6]; and a base material layer , which is provided on the aforementioned hardened material layer. (Compare the effectiveness of previous technologies)

According to the present invention, it is possible to provide a urethane prepolymer composition which has excellent storage stability and can form a hardened material layer excellent in flexibility, heat resistance and solvent resistance; and uses the urethane prepolymer composition. Moisture-hardening adhesive composed of prepolymers. Furthermore, according to the present invention, it is possible to provide a laminated body and synthetic leather using the above-mentioned urethane prepolymer composition.

〈Urethane prepolymer composition〉 Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. One embodiment of the urethane prepolymer composition of the present invention contains a urethane prepolymer (C) that is a reactant of a polyol (A) and a polyisocyanate (B), and toluene di Trimethylolpropane adduct (D) of isocyanate. The polyol (A) contains 5 to 90% by mass of the polyester polyol (A-1) having a structural unit derived from an aromatic dicarboxylic acid. Moreover, the content of the trimethylolpropane adduct (D) of toluene diisocyanate is 0.2 to 25 parts by mass relative to 100 parts by mass of the urethane prepolymer (C). Moreover, the isocyanate group content rate based on the total of the urethane prepolymer (C) and the trimethylolpropane adduct (D) of toluene diisocyanate is 1.0 to 6.0 mass %. Hereinafter, the details of the urethane prepolymer composition of this embodiment will be described.

(Urethane prepolymer (C)) The urethane prepolymer (C) (hereinafter also abbreviated as "prepolymer (C)") is a reaction product of polyol (A) and polyisocyanate (B). The molar ratio (NCO group/OH group) of the polyol (A) and the polyisocyanate (B) constituting the prepolymer (C) is preferably 1.1 to 2.2, more preferably 1.3 to 2.0, and particularly preferably 1.4 to 1.9 . By making the molar ratio (NCO group/OH group) of the isocyanate group (NCO group) of the polyisocyanate (B) to the hydroxyl group (OH group) of the polyol (A) within the above range, processability can be improved, and Produce synthetic leather that feels better. If the NCO group/OH group (molar ratio) exceeds 2.2, the flexibility of the formed hardened layer may easily decrease. In addition, the urethane prepolymer (C) is excluded from the resin having a carboxyl group or a sulfamic acid (salt) group. That is, the urethane prepolymer (C) does not contain a resin having a carboxyl group or a resin having a sulfamic acid (salt) group.

The melt viscosity of the prepolymer (C) at 100°C is preferably 120 dPa·s or less, more preferably 110 dPa·s or less, and particularly preferably 105 dPa·s or less. If the melt viscosity of the prepolymer (C) exceeds 120 dPa·s, the prepolymer (C) becomes viscous and the workability is likely to decrease, and processing may become difficult. The melt viscosity of the prepolymer (C) can be controlled, for example, by the ratio of the polyester polyol (A-1) in the polyol (A). In addition, the melt viscosity of the prepolymer (C) at 100°C can be measured using a cone and plate viscometer.

The isocyanate group (NCO group) content of the prepolymer (C) is preferably 0.5 to 8.0% by mass, more preferably 1.0 to 8.0% by mass, from the viewpoint of physical properties after curing, such as flexibility when used as synthetic leather. 6.0 mass%, particularly preferably 1.5 to 4.0 mass%. The "NCO group content rate (mass %)" in the specification of the present invention is a value measured by potentiometric titration in accordance with JIS K1603-1:2007.

[Polyol (A)] Polyol (A) contains polyester polyol (A-1) having a structural unit derived from aromatic dicarboxylic acid. Examples of aromatic dicarboxylic acids include isophthalic acid, terephthalic acid, and the like. Among them, in consideration of melt viscosity, softness, etc., isophthalic acid is preferred. Furthermore, the polyol (A) is preferably a diol having two hydroxyl groups in one molecule.

Polyester polyol (A-1) is usually a reactant of aromatic dicarboxylic acid and glycols. Examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,2-propanediol, n-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 1,9-nonanediol Alcohol and neopentyl glycol, etc.

In the polyol (A), the proportion of the polyester polyol (A-1) is 5 to 90 mass %, preferably 10 to 80 mass %, more preferably 20 to 70 mass %, particularly preferably 25 to 60 mass %. %. By setting the ratio of the polyester polyol (A-1) in the polyol (A) within the above range, a prepolymer (C) with a moderate melt viscosity that has good operability during gravure coating can be produced. ).

The number average molecular weight (Mn) of the polyester polyol (A-1) is preferably 4,000 or less, more preferably 3,000 or less, and particularly preferably 2,800 or less. If the number average molecular weight (Mn) of the polyester polyol (A-1) exceeds 4,000, the viscosity becomes too high, so the practicality may be reduced. The lower limit of the number average molecular weight (Mn) of the polyester polyol (A-1) is not particularly limited, but for example, it is preferably 500 or more. In addition, the "number average molecular weight (Mn)" in the specification of the present invention is a polystyrene-converted value measured by gel chromatography (GPC).

Polyol (A) usually further contains polyol (A-2) other than polyester polyol (A-1). The other polyol (A-2) is at least one selected from the group consisting of polyester polyol (excluding polyester polyol (A-1)), polyether polyol, and polycarbonate polyol.

As the polyester polyol other than polyester polyol (A-1), a reaction product of an aliphatic dicarboxylic acid and glycols can be used. Examples of aliphatic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, and the like. Examples of the glycols include the same glycols as those described above that can constitute the polyester polyol (A-1).

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polyethylene glycol-polytetramethylene glycol (block or random), polytetramethylene glycol, and polyhexamethylene glycol. Alcohol etc. Among them, polytetramethylene glycol is preferred from the viewpoint of flexibility.

Examples of the polycarbonate polyol include polytetramethylene carbonate diol, polypentamethylene carbonate diol, polyneopentyl carbonate diol, polyhexamethylene carbonate diol, poly( 1,4-cyclohexane dimethylene carbonate) diol, and their random/block copolymers, etc.

In the polyol (A), the proportion of other polyols (A-2) is preferably 10 to 95 mass %, more preferably 20 to 90 mass %, particularly preferably 30 to 80 mass %, and most preferably 40 to 75 Mass %. Furthermore, in the polyol (A), the total of the polyester polyol (A-1) and other polyol (A-2) is preferably 100% by mass. By further containing another polyol (A-2) in the polyol (A), a hardened material layer with more excellent flexibility can be formed.

The number average molecular weight (Mn) of the other polyol (A-2) is preferably 4,000 or less, more preferably 3,000 or less, and particularly preferably 2,800 or less. If the number average molecular weight (Mn) of other polyol (A-2) exceeds 3,000, the viscosity becomes too high, so the practicality may be reduced. In addition, the number average molecular weight (Mn) of other polyol (A-2) is preferably 500 or more. That is, it is preferable that the other polyol (A-2) does not contain so-called short-chain diols (low molecular weight diols) such as neopentyl glycol.

[Polyisocyanate (B)] As the polyisocyanate, bifunctional polyisocyanates such as aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate are preferably used. Specific examples of the polyisocyanate include toluene diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, and 4-chloro-1 ,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2,4-diisocyanate diphenyl ether, methylene diisocyanate, 4,4'-diphenylmethane diisocyanate Isocyanate, benzylidene diisocyanate, 1,5-naphthalene diisocyanate, benzidine diisocyanate, o-nitrobenzidine diisocyanate, 4,4-dibenzyl diisocyanate, 1,4-tetramethylene diisocyanate , 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylene diisocyanate, 4 , 4'-methylene bis(cyclohexyl isocyanate), 1,5-tetrahydronaphthalene diisocyanate, isophorone diisocyanate and dicyclohexylmethane 4,4'-diisocyanate, etc. Among them, 4,4'-diphenylmethane diisocyanate (MDI) is preferred.

(Production method of urethane prepolymer (C)) The prepolymer (C) can be prepared, for example, by making the polyol (A) and the polyisocyanate (B) use a single process or a multi-stage process, preferably at 20 to 150°C, more preferably at 60 to 110°C. , react until the product reaches the theoretical NCO group content rate (mass %) to produce. When the polyol (A) and the polyisocyanate (B) react, a catalyst may be used together as necessary. Examples of catalysts include metal salts or organic metal derivatives such as dibutyltin laurate, dioctyltin laurate, stannous octoate, lead octoate, and tetra-n-butyl titanate; organic amines such as triethylamine; 1,8 - Diazabicyclo[5.4.0]undec-7-ene catalyst, etc.

The polyol (A) and the polyisocyanate (B) are preferably reacted in the absence of a solvent such as an organic solvent, that is, without a solvent. The solvent-free urethane prepolymer (C) can be obtained by reacting the polyol (A) and the polyisocyanate (B) in the absence of a solvent such as an organic solvent.

(Toluene diisocyanate-trimethylolpropane adduct (D)) The urethane prepolymer composition of this embodiment contains trimethylolpropane adduct (D) of toluene diisocyanate (hereinafter also abbreviated as "TDI adduct (D)"). By containing TDI adduct (D), an adhesive layer (hardened material layer) with improved heat resistance can be formed, and a urethane prepolymer useful as a one-liquid moisture-curable adhesive can be produced. material composition. Furthermore, by containing the TDI adduct (D), a urethane prepolymer composition can be produced that can form a cured material layer that is excellent not only in heat resistance but also in flexibility and solvent resistance. .

In the urethane prepolymer composition, the content of the TDI adduct (D) relative to 100 parts by mass of the urethane prepolymer (C) is 0.2 to 25 parts by mass, preferably 0.3 ~20 parts by mass, more preferably 0.5~18 parts by mass, particularly preferably 1.0~15 parts by mass. By setting the content of the TDI adduct (D) within the above range, a urethane prepolymer composition can be produced, which can form a cured product excellent in flexibility, heat resistance, and solvent resistance. layer. If the content of the TDI adduct (D) is less than 0.2 parts by mass relative to 100 parts by mass of the prepolymer (C), a cured material layer showing sufficient heat resistance and solvent resistance cannot be formed. On the other hand, if the content of the TDI adduct (D) exceeds 25 parts by mass relative to 100 parts by mass of the prepolymer (C), the flexibility of the formed hardened material layer decreases, and the urethane prepolymer The storage stability of the polymer composition is reduced.

The isocyanate group (NCO group) content based on the total of the prepolymer (C) and the TDI adduct (D) (hereinafter also referred to as the "total NCO group content") is preferably 1.0 to 6.0 mass % It is 1.1~5.0 mass%, more preferably, it is 1.2~4.0 mass%. By setting the total NCO group content within the above range, a urethane prepolymer composition can be produced that can form a hardened material layer that is excellent in flexibility, heat resistance, and solvent resistance, and is stable in storage. Excellent performance. If the total NCO group content is less than 1.0% by mass, the heat resistance of the formed hardened material layer will decrease. On the other hand, if the total NCO group content exceeds 6.0% by mass, the softness of the formed hardened material layer will be insufficient.

＜Moisture curing adhesive＞ One embodiment of the moisture-curable adhesive of the present invention contains the aforementioned urethane prepolymer composition. The moisture-curing adhesive agent of this embodiment is particularly suitable as a liquid adhesive agent used for manufacturing various laminates in addition to synthetic leather.

In the moisture-curing adhesive of this embodiment, an appropriate amount of thermoplastic resin, tackifier resin, catalyst, pigment, antioxidant, ultraviolet absorber, surfactant, flame retardant, filler, and various additives such as foaming agents. However, it is preferable that the moisture-curable adhesive agent of this embodiment is substantially composed only of the above-mentioned urethane prepolymer composition. The moisture-hardening adhesive agent of this embodiment is suitable as an adhesive agent for synthetic leather.

The adhesive agent of this embodiment can be applied to the surface of the adherends so that the adherends can be easily adhered to each other. Examples of adherends other than the base material layer for synthetic leather include metal and non-metal (polycarbonate, glass, etc.) base materials.

＜Laminated body＞ One embodiment of the laminated body of the present invention includes: a film-like or sheet-like base material; and a hardened material layer provided on the base material and formed of a hardened material of the moisture-curable adhesive. That is, the laminate system of this embodiment includes a hardened material layer (adhesive layer) formed by moisture curing a coating film formed by applying the moisture curing adhesive or the like. As the base material, in addition to the skin layer or base material layer for synthetic leather, optical films, optical plates, flexible printed substrates, glass substrates, and substrates in which ITO is vapor-deposited on these substrates are also included.

The moisture-curable adhesive is applied to the substrate using known methods such as comma coating, knife coating, and roller coating to form a coating film. Next, the formed coating film is moisture-hardened to form a hardened material layer, thereby obtaining a laminated body.

＜Synthetic leather＞ One embodiment of the synthetic leather of the present invention includes: a skin layer; a hardened material layer provided on the skin layer and formed of a hardened material of the moisture-curable adhesive; and a base fabric provided on the hardened material layer. and other base material layers. Examples of the base fabric constituting the base material layer include fabrics including twill fabrics, plain weave fabrics, etc.; raised fabrics obtained by mechanically raising the cotton texture of the fabrics, rayon fabrics, nylon fabrics, polyester fabrics, gram fabrics, etc. Vera cloth, non-woven fabrics (polyester, nylon, various latex), various films, sheets, etc. Examples of the skin layer include those formed from skin layer forming coating materials such as solvent-based polyurethane, water-based polyurethane, and TPU.

Synthetic leather can be produced in the following manner, for example. First, the paint for forming the skin layer is coated on the release paper by known methods such as comma coating, knife coating, roller coating, gravure coating, die coating, spray coating, etc. . After the applied paint is suitably dried to form a skin layer, the moisture-curable adhesive is applied to the formed skin layer by known methods such as comma coating, knife coating, and roller coating. After the applied moisture-curing adhesive and the base material layer are pressure-bonded at 75 to 155°C, aging is performed under predetermined conditions as necessary. Secondly, by peeling off the release paper, the desired synthetic leather can be obtained. The synthetic leather of this embodiment is suitable as a material constituting shoes, clothing, bags, furniture, automobile interior materials (for example, dashboards, doors, consoles, seats), and the like. [Example]

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In addition, "parts" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified.

＜Manufacture of Prepolymer＞ (Manufacture example 1) In a glass reaction vessel equipped with a mixer, a thermometer and a gas inlet, 10 parts of isophthalic polyester polyol (Mn: 2,000) and polytetramethylene glycol 2000 (PTMG2000) (Mn: 2,000, Mitsubishi Chemical Corporation) 90 parts by mass, and 16.3 parts of 4,4'-diphenylmethane diisocyanate (MDI). As the isophthalic acid-based polyester polyol, a polyester polyol composed of isophthalic acid and 1,4-butanediol (1,4-BD) is used. Furthermore, the molar ratio (NCO group/OH group) of the NCO group of MDI to the OH group of the polyol (isophthalic polyester polyol and PTMG2000) was set to 1.3. After dehydration by heating and depressurizing, nitrogen gas was sealed. The mixture was stirred at an internal temperature of 100° C. for 120 minutes to react, and a prepolymer (C-1) was obtained. The viscosity of the obtained prepolymer (C-1) at 100°C was 95 dPa·s, and the NCO group content was 1.08%. (Manufacture Examples 2 to 14)

Prepolymers (C-2) to (C-14) were obtained in the same manner as in Production Example 1, except that the formulas shown in Tables 1-1 and 1-2 were used. The characteristics of the obtained prepolymer are shown in Tables 1-1 and 1-2. In addition, the meanings of the abbreviations in Tables 1-1 and 1-2 are as follows. In addition, the "polycarbonate polyol" in Tables 1-1 and 1-2 is a polycarbonate diol based on 1,6-hexanediol (trade name "ETERNACOLL UH-200", manufactured by Ube Kosan Co., Ltd.) . 1,4-BD: 1,4-butanediol IPA: isophthalic acid PTMG2000: polytetramethylene glycol 2000 AA: adipic acid 1,6-HD: 1,6-hexanediol TPA: terephthalic acid NPG: neopentyl glycol

[Table 1-1] (Unit of middle section: portion) Manufacturing example 1 2 3 4 5 6 7 Prepolymer (C-1) (C-2) (C-3) (C-4) (C-5) (C-6) (C-7) Isophthalic polyester polyol (1,4-BD/IPA, Mn: 2,000) 10 50 70 80 50 50 Isophthalic polyester polyol (1,4-BD/IPA, Mn: 1,000) 50 Polyether polyol (PTMG2000, Mn: 2,000) 90 50 30 20 50 Adipic acid polyester polyol (1,4-BD/AA, Mn: 2,000) 50 Polycarbonate polyol (Mn: 2,000) 50 Adipic acid polyester polyol (1,6-HD/AA, Mn: 2,000) Terephthalic acid-based polyester polyol (1,4-BD/TPA, Mn: 2,000) NPG (molecular weight: 104) MDI 16.3 18.3 22.5 25.0 22.5 22.5 28.1 NCO group/OH group (mol ratio) 1.3 1.5 1.8 2.0 1.8 1.8 1.5 Viscosity (dPa・s/100℃) 95 90 100 100 100 100 80 NCO group content rate (%) 1.08 1.77 2.74 3.36 2.74 2.74 2.46

[Table 1-2] (Unit of middle section: portion) Manufacturing example 8 9 10 11 12 13 14 Prepolymer (C-8) (C-9) (C-10) (C-11) (C-12) (C-13) (C-14) Isophthalic polyester polyol (1,4-BD/IPA, Mn: 2,000) 100 90 50 50 Isophthalic polyester polyol (1,4-BD/IPA, Mn: 1,000) 80 Polyether polyol (PTMG2000, Mn: 2,000) 50 20 25 Adipic acid polyester polyol (1,4-BD/AA, Mn: 2,000) 50 25 25 Polycarbonate polyol (Mn: 2,000) Adipic acid polyester polyol (1,6-HD/AA, Mn: 2,000) 50 25 Terephthalic acid-based polyester polyol (1,4-BD/TPA, Mn: 2,000) 50 NPG (molecular weight: 104) 10 MDI 18.3 22.5 45 25.0 53.2 22.5 22.5 NCO group/OH group (mol ratio) 1.5 1.8 2.0 2.0 1.5 1.8 1.8 Viscosity (dPa・s/100℃) 85 110 80 150 40 80 100 NCO group content rate (%) 1.77 2.74 5.21 3.36 3.89 2.74 2.74

＜Manufacture of prepolymer composition＞ (Example 1) 0.67 parts of TDI adduct (trade name "Takenate D-103H", manufactured by Mitsui Chemicals Co., Ltd.) was added to 100 parts of the prepolymer (C-1) obtained in Production Example 1 (calculated as non-volatile content). , NCO group content: 13.0%, solid content: 75%). The amount of the TDI adduct (non-volatile matter) was 0.3 parts relative to 100 parts of the non-volatile matter of the prepolymer (C-1). The mixture was heated to reduce pressure and stirred while desolvating to obtain a prepolymer composition. The total NCO group content of the obtained prepolymer composition was 1.13%.

(Examples 2 to 15, Comparative Examples 1 to 12) A prepolymer composition was obtained in the same manner as in Production Example 1 except that the formulas shown in Tables 2-1 to 2-3 were used. The total NCO group content of the obtained prepolymer composition is shown in Tables 2-1 to 2-3. In addition, the details of each component in Tables 2-1 to 2-3 are shown below. Polymer MDI: Trade name "Lupranate M20S", manufactured by BASF INOAC POLYURETHANES HDI isocyanurate: Trade name "Duranate TPA-100", manufactured by Asahi Kasei Co., Ltd. HDI adduct: Trade name "Donade AE700-100", manufactured by Asahi Kasei Co., Ltd. HDI biuret: Trade name "Donade 24A-100", manufactured by Asahi Kasei Co., Ltd.

＜Manufacture of synthetic leather＞ After applying solution type urethane resin (trade name "RESAMIN NE-8875-30M", manufactured by Dainichi Seika Industrial Co., Ltd.) on the release paper, it was dried at 120°C for 5 minutes to form a film thickness of 40 µm. Epidermal layer. On the other hand, each of the prepared prepolymer compositions (moisture curable adhesive) was coated on other release papers and then aged for 48 hours at 25°C and 60% RH to form a film thickness of 100 µm. The next layer. The adhesive layer peeled off from the release paper was sandwiched between the skin layer and the base fabric (polyester mesh material for testing). Use a sealing machine and laminate at 170°C and 0.15 MPa for 30 seconds with a heat source placed on the side of the release paper that is in contact with the skin layer. Thereafter, the release paper in contact with the epidermal layer is peeled off to obtain the synthetic leather.

＜Evaluation＞ (softness) Mix 100 parts of polyurethane resin adhesive (trade name "RESAMIN UD-8351NT", manufactured by Dainichi Seika Industrial Co., Ltd.) and isocyanate-based cross-linking agent (trade name "C-50 cross-linking agent", manufactured by Dainisei Chemical Industry Company) 10 parts, prepare adhesive. Coat the prepared adhesive on the skin layer of the release paper formed in the aforementioned "Manufacture of Synthetic Leather" to form an adhesive layer with a film thickness of 100 µm. The formed adhesive layer was preliminarily dried at 80°C for 2 minutes, and then pressure-bonded with the base material (fabric) at a lamination roller temperature of 40°C. Thereafter, it was aged at 50°C for 48 hours to obtain a standard synthetic leather for softness evaluation.

The softness of the synthetic leather is evaluated based on the evaluation criteria shown below by comparing the tactile feel of the manufactured synthetic leather and the standard synthetic leather when touched by hand. The results are shown in Tables 2-1 to 2-3. In addition, "◎", "〇" and "△" are qualified. ◎: Softer than standard synthetic leather. 〇: As soft as standard synthetic leather. △: Slightly harder than standard synthetic leather. ×: Significantly harder than standard synthetic leather.

(heat resistance) Coat the prepolymer composition heated to 100°C on the release paper. After curing for more than 48 hours at 25°C and 60% RH, it was peeled off from the release paper to obtain a translucent film with a thickness of 50 µm, a width of 8 cm, and a length of 15 cm. A heat resistance test was conducted in which the obtained film was maintained at 120° C. for 400 hours. Using a tensile testing device (model "Autograph AGS-100A", manufactured by Shimadzu Corporation), the breaking strength of the film before and after the heat resistance test was measured at 25°C and a tensile speed of 200 mm/min, as shown below. The evaluation criteria evaluate heat resistance. The results are shown in Tables 2-1 to 2-3. In addition, "◎" and "〇" are passed. ◎: The retention rate of breaking strength is over 50%. 〇: The retention rate of breaking strength is more than 25% and less than 50%. ×: The retention rate of breaking strength is less than 25%, or the film is dissolved.

(Usable time (storage stability)) The produced prepolymer composition was put into a container and stored at 100° C. for 8 hours with the container open. The viscosity of the prepolymer composition before and after storage was measured, and the potable life was evaluated based on the evaluation criteria shown below. The results are shown in Tables 2-1 to 2-3. In addition, "◎" and "〇" are passed. ◎: The viscosity change rate is less than 150%. 〇: The viscosity change rate is 150% or more and less than 250%. ×: The viscosity change rate is more than 250%.

(solvent resistance) Coat the prepolymer composition heated to 100°C on the release paper. After curing for more than 48 hours at 25°C and 60% RH, the film was peeled off from the release paper to obtain a translucent film with a thickness of 50 µm, a width of 5 cm, and a length of 5 cm. The obtained film was immersed in acetone for 10 minutes and then taken out. The linear expansion coefficient of the taken-out film was calculated (={(width of the film after immersion)/(width of the film before immersion)}×100 (%)), and the solvent resistance was evaluated based on the standards shown below. The results are shown in Tables 2-1 to 2-3. In addition, "◎" and "〇" are passed. ◎: The linear expansion rate of one side of the film is less than 120%. 〇: The linear expansion rate of one side of the film is more than 120% and less than 150%. △: The linear expansion rate of one side of the film is more than 150%. ×: The film is dissolved.

[table 2-1] Example 1 2 3 4 5 6 7 8 9 Prepolymer Kind (C-1) (C-1) (C-1) (C-2) (C-2) (C-2) (C-3) (C-3) (C-4) Quantity (portions) 100 100 100 100 100 100 100 100 100 TDI adduct (NCO base: 13.0%) Quantity (portions) 0.3 5 10 0.5 10 20 0.5 10 20 Polymer MDI (NCO base: 31.3%) Quantity (portions) HDI isocyanurate (NCOg: 23.1%) Quantity (portions) HDI adduct (NCO base: 11.9%) Quantity (portions) HDI biuret (NCO base: 23.5%) Quantity (portions) Total NCO base content rate (%) 1.13 1.86 2.56 1.85 3.18 4.36 2.82 4.07 5.69 Softness ◎ ◎ 〇 ◎ ◎ 〇 ◎ ◎ 〇 heat resistance 〇 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ Available time 〇 〇 〇 〇 〇 〇 〇 〇 〇 Solvent resistance 〇 〇 ◎ 〇 ◎ ◎ 〇 ◎ ◎

[Table 2-2] Example Comparative example 10 11 12 13 14 15 1 2 3 4 Prepolymer Kind (C-5) (C-6) (C-7) (C-9) (C-13) (C-14) (C-2) (C-4) (C-2) (C-2) Quantity (portion) 100 100 100 100 100 100 100 100 100 100 TDI adduct (NCO base: 13.0%) Quantity (portions) 10 10 10 10 10 10 30 Polymer MDI (NCO base: 31.3%) Quantity (portion) 5 HDI isocyanurate (NCO group: 23.1%) Quantity (portion) HDI adduct (NCO base: 11.9%) Quantity (portion) HDI biuret (NCO base: 23.5%) Quantity (portion) Total NCO base content rate (%) 4.07 4.07 3.81 4.07 4.07 4.07 1.77 3.36 5.36 3.17 Softness ◎ 〇 〇 △ ◎ 〇 ◎ × × × heat resistance ◎ ◎ ◎ 〇 ◎ ◎ × × ◎ 〇 Available time 〇 〇 〇 〇 〇 〇 〇 〇 × × Solvent resistance ◎ ◎ ◎ 〇 ◎ ◎ × × 〇 〇

[Table 2-3] Comparative example 5 6 7 8 9 10 11 12 Prepolymer Kind (C-2) (C-8) (C-2) (C-2) (C-2) (C-10) (C-11) (C-12) Quantity (portions) 100 100 100 100 100 100 100 100 TDI adduct (NCO base: 13.0%) Quantity (portions) 10 10 20 10 Polymer MDI (NCO base: 31.3%) Quantity (portions) 10 HDI isocyanurate (NCO group: 23.1%) Quantity (portions) 10 HDI adduct (NCO base: 11.9%) Quantity (portions) 10 HDI biuret (NCO base: 23.5%) Quantity (portion) 10 Total NCO base content rate (%) 4.45 3.18 3.71 2.69 3.74 6.32 5.69 5.11 Softness × × △ 〇 〇 × × × heat resistance 〇 〇 ◎ ◎ ◎ 〇 ◎ ◎ Available time × 〇 ◎ ◎ ◎ ◎ 〇 × Solvent resistance 〇 〇 △ △ △ 〇 ◎ ◎

It is found that by using the TDI adduct, mechanical strength such as solvent resistance necessary for synthetic leather applications is improved compared to the case of using aliphatic polyisocyanate such as HDI. Furthermore, it was found that by using the TDI adduct, the flexibility and pot life that cannot be obtained by using polymerized MDI are improved. Furthermore, it is found that even when a TDI adduct is used, unless a polyol (A) containing a specific amount of polyester polyol (A-1) having a structural unit derived from an aromatic dicarboxylic acid is used, The resulting synthetic leather had poor softness (Comparative Example 6). (industrial availability)

The urethane prepolymer composition of the present invention is useful as an adhesive for manufacturing synthetic leather and various laminates.

Claims (8)

A urethane prepolymer composition containing: Urethane prepolymer (C) which is a reactant of polyol (A) and polyisocyanate (B), and Toluene diisocyanate trimethylolpropane adduct (D); and The aforementioned polyol (A) contains 5 to 90 mass % of a polyester polyol (A-1) having a structural unit derived from an aromatic dicarboxylic acid; The content of the trimethylolpropane adduct (D) of toluene diisocyanate is 0.2 to 25 parts by mass relative to 100 parts by mass of the aforementioned urethane prepolymer (C); The isocyanate group content rate based on the total of the above-mentioned urethane prepolymer (C) and the above-mentioned trimethylolpropane adduct of toluene diisocyanate (D) is 1.0 to 6.0 mass%; The aforementioned polyol (A) further contains at least one selected from the group consisting of polyester polyol (excluding the aforementioned polyester polyol (A-1)), polyether polyol, and polycarbonate polyol. Other polyols (A-2); In the aforementioned polyol (A), the proportion of the aforementioned other polyol (A-2) is 10 to 95% by mass. The urethane prepolymer composition of claim 1, wherein the urethane prepolymer (C) is a resin having a carboxyl group or a sulfamic acid (salt) group. The urethane prepolymer composition of claim 1 or 2, wherein the proportion of the aforementioned polyester polyol (A-1) in the aforementioned polyol (A) is 5 to 70 mass%; In the aforementioned polyol (A), the proportion of the aforementioned other polyol (A-2) is 30 to 95% by mass. The urethane prepolymer composition of claim 1 or 2, wherein the molar ratio (NCO group/OH group) of the aforementioned polyol (A) and the aforementioned polyisocyanate (B) is 1.3 to 2.0. The urethane prepolymer composition of claim 1 or 2, wherein the melt viscosity of the aforementioned urethane prepolymer (C) at 100°C is 110 dPa·s or less. A moisture-hardening adhesive containing the urethane prepolymer composition according to any one of claims 1 to 5. A laminated body, which includes: a base material; and A hardened material layer is provided on the aforementioned base material and is formed of a hardened material of the moisture curing adhesive according to claim 6. A kind of synthetic leather, which has: epidermis layer; A hardened material layer is provided on the aforementioned skin layer and is formed of a hardened material of the moisture-hardening adhesive of claim 6; and A base material layer is provided on the aforementioned hardened material layer.