WO2023214494A1

WO2023214494A1 - Moisture-curable urethane hot melt resin composition, multilayer body and synthetic artificial leather

Info

Publication number: WO2023214494A1
Application number: PCT/JP2023/014164
Authority: WO
Inventors: 寛女奥泉; 一弥佐々木
Original assignee: 大日精化工業株式会社
Priority date: 2022-05-02
Filing date: 2023-04-06
Publication date: 2023-11-09
Also published as: TW202348669A; JP2023165179A; JP7209883B1

Abstract

The present invention provides a moisture-curable urethane hot melt resin composition which is capable of forming a cured product layer that has good initial adhesiveness, heat resistance, hydrolysis resistance, alcohol resistance and wear resistance.　This moisture-curable urethane hot melt resin composition contains a urethane prepolymer having an isocyanate group, the urethane prepolymer being a reaction product of a polyol component and a polyisocyanate component. The polyol component contains a high molecular weight polyol component and a low molecular weight polyol component. The high molecular weight polyol component contains: at least one polyol (A) that is selected from the group consisting of SA polyester polyols (A1), 1,4-BD/AA polyester polyols (A2) having a number average molecular weight (Mn) of 8,000 or more, and 1,6-HD/AA polyester polyols (A3) having an Mn of 6,000 or more; and at least one polyol (B) that is selected from the group consisting of polyester polyols (B1) other than the polyol (A) and polyether polyols (B2). The low molecular weight polyol component contains a trifunctional polyol (D) that has three hydroxyl groups in each molecule, while having a molecular weight of 300 or less. The ratio between the polyol (A) and the trifunctional polyol (D) satisfies (trifunctional polyol (D) (mmol))/(polyol (A) (g)) = 0.14 to 55 mmol/g.

Description

Moisture-curable urethane hot melt resin composition, laminate, and synthetic fake leather

The present invention relates to a moisture-curable urethane hot-melt resin composition, a laminate, and a synthetic simulated leather.

A moisture-curable urethane hot-melt resin composition is a composition that is solid at room temperature and can be prepared without a solvent, and is a resin composition that is cured by moisture after being heated and melted and applied. For this reason, moisture-curable urethane hot melt resin compositions are widely used as various adhesives that are environmentally friendly because they do not use solvents. Such moisture-curable urethane hot melt resin compositions contain functional groups such as isocyanate groups (NCO groups) that can react with water (moisture) present in the air or in the substrate to which they are applied to form a crosslinked structure. Contains a urethane prepolymer that has in its molecule.

Moisture-curable urethane hot-melt resin compositions, when used as various adhesives, develop adhesive strength through moisture curing, making it difficult to develop excellent initial strength. Techniques have been proposed to express this. For example, Patent Document 1 describes a "urethane prepolymer (1)" that is derived from an organic polyisocyanate compound (a) and a predetermined polyol (b1) and has an NCO group, and a "urethane prepolymer (1)" that has no active hydrogen and has tackifying properties. A reactive hot melt adhesive containing a "low molecular weight xylene resin (d1)" having the following properties is disclosed.

Japanese Patent Application Publication No. 5-065471

The urethane prepolymer used in moisture-curable urethane resin compositions is also used as an adhesive in the production of synthetic pseudo-leather such as artificial leather and synthetic leather. Synthetic fake leather is used as a material for manufacturing a variety of products such as shoes, clothing, bags, furniture, and vehicle interior materials (eg, instrument panels, doors, consoles, seats). Conventional synthetic fake leather is generally a laminate in which a skin layer, an adhesive layer (cured material layer), and a base material layer are laminated in this order, and the cured material layer is formed of various urethane prepolymers. There is. The cured material layer constituting the synthetic simulated leather used in the various products mentioned above is required to have good flexibility as well as heat resistance that can withstand the heat during manufacturing processing.

The reactive hot melt adhesive disclosed in Patent Document 1 mentioned above has a certain effect on the initial adhesive strength after curing in a predetermined humidity environment. However, such conventional moisture-curing urethane hot-melt resin compositions have a low heat softening point after curing, and have a smaller network structure after curing compared to two-part curable polyurethane resin compositions. Therefore, there is a limit to its application to applications that require heat resistance and processing at high temperatures, such as the above-mentioned synthetic simulated leather. In addition, when conventional moisture-curable urethane hot melt resin compositions are used for clothing, they have insufficient hydrolysis resistance to withstand washing, as well as insufficient abrasion resistance and There is a risk that peeling from the base material may occur due to friction such as. In addition, the current coronavirus pandemic requires resistance to alcohol disinfection.

Therefore, the present invention provides a moisture-curable urethane hot melt resin composition that can form a cured layer with good initial adhesion, heat resistance, flexibility, hydrolysis resistance, alcohol resistance, and abrasion resistance. This is what we are trying to provide.

The present invention contains a urethane prepolymer having an isocyanate group that is a reaction product of a polyol component and a polyisocyanate component, the polyol component includes a high molecular polyol component and a low molecular polyol component, and the high molecular polyol component is a polyester polyol (A1) having a constitutional unit derived from sebacic acid; a polyester polyol (A1) having a number average molecular weight of 8,000 or more and having a constitutional unit derived from 1,4-butanediol and adipic acid; A2); and at least one polyester polyol (A3) having a number average molecular weight of 6,000 or more and having a constitutional unit derived from 1,6-hexanediol and a constitutional unit derived from adipic acid; a polyol (A); and at least one polyol (B) selected from the group consisting of a polyester polyol (B1) other than the polyol (A); and a polyether polyol (B2); The component contains a trifunctional polyol (D) having a molecular weight of 300 or less and having three hydroxyl groups in one molecule, and the ratio of the polyol (A) to the trifunctional polyol (D) is the same as the trifunctional polyol (D) ( Provided is a moisture-curable urethane hot melt resin composition that satisfies the following: mmol)/the polyol (A) (g) = 0.14 to 55 mmol/g.

According to the present invention, a moisture-curable urethane hot-melt resin composition is capable of forming a cured material layer with good initial adhesion, heat resistance, flexibility, hydrolysis resistance, alcohol resistance, and abrasion resistance. can provide things.

It is a typical explanatory view explaining the form of the sample used for evaluation of an example. It is an explanatory view explaining the form of the gear oven used in evaluation of an example.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

<Moisture-curable urethane hot melt resin composition>
The moisture-curable urethane hot melt resin composition (hereinafter sometimes simply referred to as "resin composition") of one embodiment of the present invention is a urethane prepolymer that is a reaction product of a polyol component and a polyisocyanate component. Contains. This urethane prepolymer has isocyanate groups. Because of the isocyanate groups, urethane prepolymers can form crosslinked structures by reacting with water (moisture) present in the air or in the substrate to which the resin composition is applied. The resin composition has moisture curability.

The polyol component used in the urethane prepolymer includes a high molecular polyol component and a low molecular polyol component. The polymer polyol component includes a polyol (A) and a polyol (B) described below. Polyol (A) is a polyester polyol (A1) having a structural unit derived from sebacic acid; a number average molecular weight having a structural unit derived from 1,4-butanediol and adipic acid and having a number average molecular weight of 8,000 or more. polyester polyol (A2); and polyester polyol (A3) having a number average molecular weight of 6,000 or more and having a structural unit derived from 1,6-hexanediol and a structural unit derived from adipic acid. At least one type. The polyol (B) is at least one selected from the group consisting of a polyester polyol (B1) other than the polyol (A); and a polyether polyol (B2). Moreover, the low-molecular polyol component includes a trifunctional polyol (D) having a molecular weight of 300 or less and having three hydroxyl groups in one molecule. In this resin composition, the ratio of polyol (A) and trifunctional polyol (D) satisfies trifunctional polyol (D) (mmol)/polyol (A) (g) = 0.14 to 55 mmol/g. .

With the above structure, the moisture-curable urethane hot melt resin composition of this embodiment forms a cured layer with good initial adhesion, heat resistance, flexibility, hydrolysis resistance, alcohol resistance, and abrasion resistance. It is possible to do so. Further, in one embodiment, this resin composition has good stability over time in a molten state. Furthermore, in one embodiment, this resin composition can contribute to providing synthetic pseudo-leather with good cold flexibility, hydrolysis resistance, flexibility, abrasion resistance, and heat resistance.

From the viewpoint of easily obtaining the above-mentioned effects, the preferred structure of the resin composition of this embodiment will be described in detail below. In addition, in the description of the following compounds (each polyol component, polyisocyanate component, etc.), unless otherwise specified, each of the compounds in the description can be used singly or in combination of two or more.

[Urethane prepolymer]
The urethane prepolymer is a reaction product of a polyol component and a polyisocyanate component, and has isocyanate groups. The urethane prepolymer is preferably obtained by polyaddition reaction of a polyol component and a polyisocyanate component, more preferably obtained by polyaddition of a polyol component and an excess polyisocyanate component, and has an isocyanate group at the terminal. It is a urethane prepolymer.

The equivalent ratio (mole ratio; NCO group/OH group) of the isocyanate group (NCO group) of the polyisocyanate component to the hydroxyl group (OH group) of the polyol component constituting the urethane prepolymer is 1.1 to 2.2. It is preferably from 1.4 to 2.0, even more preferably from 1.5 to 1.9. By setting the NCO group/OH group within the above range, processability at high temperatures is improved when used for clothing, and it becomes possible to produce synthetic simulated leather with a better texture.

The urethane prepolymer is preferably the main component of the resin composition from the viewpoint of causing the resin composition to exhibit moisture curability. The content of the urethane prepolymer may be 100% by mass, preferably 50% by mass or more, more preferably 70% by mass or more, and 90% by mass, based on the mass of the solid content of the resin composition. It is more preferable that it is above.

[Polyol component]
The polyol component used in the urethane prepolymer includes a high molecular polyol component and a low molecular polyol component. The high molecular weight polyol component is a polyol group having a higher molecular weight than the low molecular weight polyol component, and preferably a polymer is used. The low molecular weight polyol component is a polyol group having a lower molecular weight than the high molecular weight polyol component.

(High molecular polyol component)
The polymer polyol component used in the urethane prepolymer includes a polyol (A) described below and a polyol (B) other than the polyol (A). In the polyol component, the high molecular polyol component is preferably the main component of the polyol component, and is preferably used in a larger amount than the low molecular polyol component. The proportion of the polymeric polyol component in the polyol component is preferably 60 to 99.8% by mass, more preferably 80 to 99.5% by mass, and 90 to 99% by mass, based on the total amount of polyol components. More preferably, it is expressed in mass %.

(Polyol (A))
The polyol (A) is at least one selected from the group consisting of the following polyester polyols (A1) to (A3).
(A1): Polyester polyol having a structural unit derived from sebacic acid (A1)
(A2): Polyester polyol having a number average molecular weight of 8,000 or more and having a structural unit derived from 1,4-butanediol and a structural unit derived from adipic acid (A2)
(A3): Polyester polyol having a number average molecular weight of 6,000 or more and having a structural unit derived from 1,6-hexanediol and a structural unit derived from adipic acid (A3)

The above polyester polyols (A1) to (A3) are crystalline polyols and can be in a solid state at 60°C. By using the polyol (A), the resin composition can form a cured layer with good initial adhesion and flexibility, and also has even better cold resistance, flexibility, and heat resistance. It becomes easier to obtain synthetic fake leather. From these viewpoints, it is preferable to use at least polyester polyol (A1) among polyols (A).

The polyester polyol (A1) has a structural unit derived from sebacic acid (SA). Hereinafter, a polyester polyol having a structural unit derived from sebacic acid may be referred to as "SA-based polyester polyol." The SA-based polyester polyol (A1) is a reaction product of sebacic acid and diols, and is a bifunctional (2 hydroxyl group) polyol (diol). Preferably, it is an SA polyester polyol (A1) obtained by polycondensing sebacic acid and diols.

Examples of diols used in the SA polyester polyol (A1) include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, hexylene glycol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 1,9 -nonanediol, neopentyl glycol, etc. Among these, 1,6-hexanediol is preferred. That is, the polyester polyol (A1) is a polyester polyol having a structural unit derived from sebacic acid and a structural unit derived from 1,6-hexanediol (hereinafter referred to as "1,6-HD/SA polyester polyol"). ) is preferable.

The number average molecular weight (Mn) of the SA polyester polyol (A1) is preferably 2,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, and Preferably, it is 20,000 or less. The "number average molecular weight (Mn)" in this specification is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene. Specifically, it is measured by GPC analysis under the following conditions (the same applies to the following examples) using dimethylformamide (DMF) as a mobile phase.
・Measuring device: High-speed GPC device (product name "HLC-8220GPC", manufactured by Tosoh Corporation)
・Column: TSK gel Super HM-N x 2,
TSK guardcolumn Super HH x 1 ・Detector: RI (differential refractometer)
・Column temperature: 40℃
・Flow rate: 0.5mL/min ・Injection volume: 50μL

The polyester polyol (A2) has a structural unit derived from 1,4-butanediol and a structural unit derived from adipic acid. Hereinafter, a polyester polyol having a structural unit derived from 1,4-butanediol and a structural unit derived from adipic acid may be referred to as a "1,4-BD/AA polyester polyol." The 1,4-BD/AA polyester polyol (A2) is a reaction product of 1,4-butanediol and adipic acid, and is a bifunctional (2 hydroxyl group) polyol (diol). Preferably, it is a polyester polyol (A2) obtained by polycondensing 1,4-butanediol and adipic acid.

The number average molecular weight (Mn) of the 1,4-BD/AA polyester polyol (A2) is 8,000 or more. By using the 1,4-BD/AA polyester polyol (A2) with Mn of 8,000 or more, the resin composition can form a cured layer with good initial adhesion, and is also cold resistant. It becomes easier to obtain synthetic fake leather with even better flexibility and flexibility. The Mn of the 1,4-BD/AA polyester polyol (A2) is preferably 20,000 or less.

The polyester polyol (A3) has a structural unit derived from 1,6-hexanediol and a structural unit derived from adipic acid. Hereinafter, a polyester polyol having a structural unit derived from 1,6-hexanediol and a structural unit derived from adipic acid may be referred to as a "1,6-HD/AA polyester polyol." The 1,6-HD/AA polyester polyol (A3) is a reaction product of 1,6-hexanediol and adipic acid, and is a bifunctional (two hydroxyl group) polyol (diol). Preferably, it is a polyester polyol (A3) obtained by polycondensing 1,6-hexanediol and adipic acid.

The number average molecular weight (Mn) of the 1,6-HD/AA polyester polyol (A3) is 6,000 or more. By using the 1,6-HD/AA polyester polyol (A3) with Mn of 6,000 or more, the resin composition can form a cured layer with good initial adhesion, and is also cold resistant. It becomes easier to obtain synthetic fake leather with even better flexibility and flexibility. The Mn of the 1,6-HD/AA polyester polyol (A3) is preferably 20,000 or less.

From the viewpoint that the above-mentioned effects of polyol (A) can be easily expressed in a well-balanced manner with the effects of other polyols described later, the proportion of polyol (A) in the polymer polyol component is set to 0 based on the total amount of the polymer polyol component. It is preferably .5 to 30% by weight, more preferably 1 to 20% by weight, and even more preferably 2 to 15% by weight.

(Polyol (B))
The polyol (B) is at least one selected from the group consisting of a polyester polyol (B1) other than the polyol (A) described above; and a polyether polyol (B2).

Polyester polyol (B1) and polyether polyol (B2) other than polyol (A) are polyols with lower crystallinity than polyol (A), and can be in a liquid state at 60°C. By using at least one of polyester polyol (B1) and polyether polyol (B2), the resin composition can form a cured layer with good flexibility, and also has good cold resistance and flexibility. It becomes easier to obtain synthetic fake leather with good flexibility etc.

The polyester polyol (B1) includes the above-mentioned SA polyester polyol (A1), a 1,4-BD/AA polyester polyol (A2) having an Mn of 8,000 or more, and a 1,6- polyester polyol having an Mn of 6,000 or more. It is a polyester polyol other than the HD/AA polyester polyol (A3). The polyester polyol (B1) is a reaction product of dicarboxylic acids and diols, and is a bifunctional (two hydroxyl group) polyol (diol). Preferably, it is a polyester polyol (B1) obtained by polycondensing dicarboxylic acids and diols.

Examples of the dicarboxylic acids used in the polyester polyol (B1) include aliphatic dicarboxylic acids such as succinic acid, adipic acid, glutaric acid, and azelaic acid; and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid. ; can be mentioned. As the diols used for the polyester polyol (B1), the same diols as those described in the description of the SA polyester polyol (A1) can be mentioned.

Specific examples of polyester polyol (B1) include polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyneopentyl adipate diol, polyethylene/butylene adipate diol, polyneopentyl/hexyl adipate diol, poly-3- Examples include methylpentane adipate diol and polybutylene isophthalate diol.

Among the polyester polyols (B1), 1,4 polyols have a structural unit derived from 1,4-butanediol and a structural unit derived from adipic acid, and have a number average molecular weight (Mn) of 1,000 to 5,000. -BD/AA polyester polyol (B1) is preferred. Among these, polybutylene adipate diol having an Mn of 1,200 to 4,000 is more preferred, and polybutylene adipate diol having an Mn of 1,500 to 3,000 is even more preferred.

The polyether polyol (B2) is a bifunctional (two hydroxyl group) polyol (diol). The polyether polyol (B2) can be obtained, for example, by polymerizing or copolymerizing either an alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) or a heterocyclic ether (tetrahydrofuran, 2-methyltetrahydrofuran, etc.). It will be done. Further, the polyether polyol (B2) can also be obtained by a dehydration condensation reaction of a diol such as 1,3-propanediol.

Examples of the polyether polyol (B2) include polyethylene glycol, polypropylene glycol, polyethylene glycol-polytetramethylene glycol (block or random), polytrimethylene ether glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol. can be mentioned. Among these, polyethylene glycol, polytrimethylene ether glycol, and polytetramethylene ether glycol are preferred from the viewpoint of flexibility.

In one embodiment of the moisture-curable urethane hot melt resin composition, from the viewpoint of making the composition more environmentally friendly, the polyol (B) (the above-mentioned polyester polyol (B1) and/or polyether polyol (B2)) is It is preferable to include a polyol (B _b ) using plant-derived raw materials. Polyols (B _b ) using plant-derived raw materials may also be referred to as biomass polyols (B _b ). Examples of polyols (B _b ) using plant-derived raw materials include polyester polyols in which one or more plant-derived diols (preferably diols having 2 to 4 carbon atoms) are used as raw materials. (B _b 1), polyether polyol (B _b 2), and polyether polyol (B _b 2) in which plant-derived tetrahydrofuran or the like is used. Examples of plant-derived diols having 2 to 4 carbon atoms include plant-derived ethylene glycol, 1,2-propanediol, 1,3-propanediol, and 1,4-butanediol.

From the viewpoint that the above-mentioned effects of polyol (B) are easily expressed in a well-balanced manner with the effects of other polyols, the proportion of polyol (B) in the polymer polyol component is 10 to 98% based on the total amount of the polymer polyol component. It is preferably 50 to 95 mass %, and even more preferably 60 to 90 mass %.

(Polycarbonate polyol (C))
It is preferable that the polymer polyol component further contains a polycarbonate polyol (C) in addition to the above-mentioned polyol (A) and polyol (B). By using polycarbonate polyol (C), it becomes easier to obtain a cured material layer and synthetic fake leather with even better hydrolysis resistance and abrasion resistance.

The polycarbonate polyol (C) is obtained, for example, by condensing diols such as 1,4-butanediol and 1,6-hexanediol with a dialkyl carbonate while performing a dealcoholization reaction. The polycarbonate polyol (C) is a bifunctional (two hydroxyl group) polyol (diol), and both crystalline and amorphous polyols can be used.

Examples of the polycarbonate polyol (C) include polytetramethylene carbonate diol, polypentamethylene carbonate diol, polyneopentyl carbonate diol, polyhexamethylene carbonate diol, poly(1,4-cyclohexane dimethylene carbonate) diol, and these. Examples include random/block copolymers. Among these, polyhexamethylene carbonate diol (polycarbonate diol based on 1,6-hexanediol), poly(tetramethylene/decamethylene) carbonate diol (polycarbonate diol based on 1,4-butanediol and 1,10-decanediol) ), and poly(pentamethylene/hexamethylene) carbonate diols (carbonate diols based on 1,5-pentanediol and 1,6-hexanediol) are preferred.

In one embodiment of the moisture-curable urethane hot melt resin composition, from the viewpoint of making the composition more environmentally friendly, the polycarbonate polyol (C) preferably includes a polycarbonate polyol (C _b ) using a plant-derived raw material. . Polycarbonate polyol (C _b ) using plant-derived raw materials may also be referred to as biomass polycarbonate polyol (C _b ). Examples of polycarbonate polyols (C _b ) using plant-derived raw materials include polycarbonate polyols in which one or more plant-derived diols (preferably diols having 2 to 10 carbon atoms) are used as raw materials. (C _b ) and the like. Examples of plant-derived diols include plant-derived ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, and 1,10-decanediol.

From the viewpoint that the above-mentioned effects of polycarbonate polyol (C) are easily expressed in a well-balanced manner with the effects of polyols (A) and (B), the proportion of polycarbonate polyol (C) in the polymer polyol component is determined by the total amount of the polymer polyol component. The amount is preferably 0 to 80% by weight, more preferably 4 to 40% by weight, and even more preferably 8 to 30% by weight.

When the polymer polyol component contains polycarbonate polyol (C), the total amount of polyol (B) and polycarbonate polyol (C) is , is preferably larger than the amount of polyol (A). Furthermore, in this case, the ratio of the total (total mass) of polyol (A), polyol (B), and polycarbonate polyol (C) to the total amount (total mass) of the polyol components is preferably 90% by mass or more. . The total amount of the polyol (A), polyol (B), and polycarbonate polyol (C) may be the total amount of the polymer polyol component. Therefore, as described above regarding the proportion of the polymeric polyol component in the polyol component, the total proportion of polyol (A), polyol (B), and polycarbonate polyol (C) to the total amount of polyol components is 99.8% by mass. It is preferably at most 99.5% by mass, more preferably at most 99% by mass.

(Low molecular polyol component)
The low molecular weight polyol component used in the urethane prepolymer is preferably used in a smaller amount than the above-mentioned high molecular weight polyol component in the polyol component. The proportion of the low molecular weight polyol component in the polyol component is preferably 0.2 to 40% by mass, more preferably 0.5 to 20% by mass, and 1 to 10% by mass, based on the total amount of polyol components. More preferably, it is expressed in mass %.

(Trifunctional polyol (D))
The low-molecular-weight polyol component used in the urethane prepolymer includes a trifunctional polyol (D) having three hydroxyl groups in one molecule and having a molecular weight (chemical formula weight) of 300 or less. In addition to the trifunctional polyol (D), the low-molecular polyol component may contain other low-molecular polyols (E) as necessary.

Since the trifunctional polyol (D) has three hydroxyl groups in one molecule, it may be called a triol (D). By using this specific low-molecular-weight trifunctional polyol (D), it is possible to obtain the moisture-curable urethane hot melt resin composition aimed at in the present disclosure.

Examples of the trifunctional polyol (D) having a molecular weight of 300 or less include glycerin, trimethylolethane, trimethylolpropane, butanetriol, pentanetriol, hexanetriol, heptanetriol, and octanetriol. Among these, glycerin and trimethylolpropane are preferred.

The amount of trifunctional polyol (D) used is within the following range in relation to the aforementioned polyol (A). That is, the ratio of polyol (A) and trifunctional polyol (D) satisfies trifunctional polyol (D) (mmol)/polyol (A) (g) = 0.14 to 55 mmol/g. By setting the trifunctional polyol (D) in an amount of 0.14 mmol or more and 55 mmol or less with respect to the unit mass (1 g) of the polyol (A), the moisture-curable urethane hot melt resin composition aimed at in the present disclosure can be obtained. I can do it. From the viewpoint of easily obtaining the desired resin composition, the trifunctional polyol (D) (mmol)/polyol (A) (g) is preferably 0.3 mmol/g or more, and 0.5 mmol/g or more. More preferably, it is 1 mmol/g or more. Further, the trifunctional polyol (D) (mmol)/polyol (A) (g) is preferably at most 30 mmol/g, more preferably at most 20 mmol/g, and preferably at least 10 mmol/g. More preferred.

From the viewpoint that the above-mentioned effect of the trifunctional polyol (D) is easily expressed, the proportion of the trifunctional polyol (D) in the low molecular polyol component is 50 to 100% by mass based on the total amount of the low molecular polyol component. The amount is preferably from 70 to 100% by weight, even more preferably from 90 to 100% by weight.

Examples of other low-molecular polyols (E) include low-molecular diols and tetrafunctional or higher-functional low-molecular polyols. Examples of the low molecular weight diols include those similar to the diols described in the description of the SA polyester polyol (A1). Examples of low-molecular-weight polyols having four or more functionalities include diglycerin, pentaerythritol, dipentaerythritol, and the like.

[Polyisocyanate component]
The polyisocyanate component used in the urethane prepolymer is not particularly limited, and a compound (polyisocyanate) having two or more isocyanate groups in one molecule can be used. Examples of the polyisocyanate include aromatic diisocyanates, alicyclic diisocyanates, aliphatic diisocyanates, and modified aliphatic diisocyanates. Among these, aromatic diisocyanates, alicyclic diisocyanates, and modified aliphatic diisocyanates are preferred, aromatic diisocyanates and modified aliphatic diisocyanates are more preferred, and aromatic diisocyanates are even more preferred.

Examples of the aromatic diisocyanate include 4,4'-diphenylmethane diisocyanate (MDI), 2,2'-MDI, 2,4'-MDI, 2,4-tolylene diisocyanate (TDI), 2,6-TDI, m-xylylene diisocyanate (XDI), 1,4-phenylene diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2 , 4-diisocyanate diphenyl ether, 1,5-naphthalene diisocyanate, and benzidine diisocyanate. Among these, MDI is preferred.

Examples of alicyclic diisocyanates include 4,4'-methylenebis(cyclohexyl isocyanate), isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)cyclohexane (hydrogenated XDI), dicyclohexylmethane-4,4' -diisocyanate (hydrogenated MDI), and 1-methylcyclohexane-2,4-diisocyanate (hydrogenated TDI).

Examples of the aliphatic diisocyanate include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), and 1,10-decamethylene diisocyanate.

Examples of modified aliphatic diisocyanates include isocyanurates, allophanates, biurets, and adducts with polyols (trimethylolpropane, etc.) of aliphatic diisocyanates. Among these, allophanate forms of aliphatic diisocyanates are preferred, and allophanate forms of HDI are more preferred.

[Production method of urethane prepolymer]
The urethane prepolymer is produced by, for example, combining a polyol component and a polyisocyanate component by a one-shot method or a multi-stage method, preferably at 60 to 150°C, more preferably at 60 to 110°C, so that the product has a theoretical NCO group content (mass %). ) can be produced by reacting until it becomes. When the polyol component and the polyisocyanate component are reacted, a catalyst may be used in combination as necessary. Catalysts include metal salts and organometallic derivatives such as dibutyltin laurate, dioctyltin laurate, stannath octoate, lead octylate, and tetra-n-butyl titanate; organic amines such as triethylamine; diazabicycloundecene catalysts. ; and so on.

It is preferable that the polyol component and the polyisocyanate component are reacted in the absence of a solvent such as an organic solvent, that is, without a solvent. A solvent-free urethane prepolymer can be obtained by reacting a polyol component and a polyisocyanate component in the absence of a solvent such as an organic solvent.

It is preferable to use various polyols so that the amount of the polyol component used in producing the urethane prepolymer falls within the above-mentioned ratio range regarding the polyol component. For example, for the polymer polyol component, polyol (A), polyol (B), and polycarbonate polyol (C) used as necessary are each added in amounts within the above-mentioned ratio range in the polymer polyol component. It is preferable to use Further, the trifunctional polyol (D) used as the low-molecular polyol component is preferably used in an amount within the range of the ratio of the low-molecular polyol component in the polyol component described above. As a preferable example, the amount of trifunctional polyol (D) used is 0.5 to 30 parts by mass based on 100 parts by mass of the total of polyol (A), polyol (B), and polycarbonate polyol (C). The amount is preferably from 0.5 to 20 parts by weight, even more preferably from 0.5 to 10 parts by weight.

The moisture-curable urethane hot-melt resin composition contains a thermoplastic resin, a tackifying resin, a catalyst, a pigment, an antioxidant, an ultraviolet absorber, a surfactant, a flame retardant, a filler, and a blowing agent, as necessary. Appropriate amounts of various additives such as the following may be blended. However, the moisture-curable urethane hot melt resin composition may be comprised essentially only of the above-mentioned urethane prepolymer. Even when the resin composition is substantially composed only of the urethane prepolymer, the composition may contain components that may be unavoidably present due to the production of the urethane prepolymer.

As detailed above, in one aspect, the moisture-curable urethane hot melt resin composition has good stability over time in a molten state, as well as initial adhesion, heat resistance, alcohol resistance, flexibility, and resistance. It is possible to form a cured material layer with good hydrolyzability and abrasion resistance. Therefore, this resin composition is suitable for applications that require heat resistance and high-temperature processing, such as synthetic fake leather, and applications that require washing resistance and abrasion resistance, such as clothing. It is expected that the processability and applications will be expanded.

Further, by using this moisture-curable urethane hot melt resin composition, it is possible to provide a laminate such as synthetic fake leather that has good cold resistance, hydrolysis resistance, flexibility, abrasion resistance, and heat resistance. is also possible. For example, the resin composition described above can be used as a hot melt adhesive for bonding a base material layer such as a base fabric constituting synthetic simulated leather and a skin layer. In addition, this resin composition can form a cured layer with good initial adhesion and abrasion resistance, so it also maintains good adhesion to a base material layer such as base fabric and is durable. It is also possible to form a cured material layer that also has the performance as a skin layer such as wear resistance.

<Laminated body>
A laminate according to an embodiment of the present invention includes a base material and a cured product layer of the above-mentioned moisture-curable urethane hot melt resin composition provided on the base material. When the resin composition is used as a hot melt adhesive, the base material can be used as one adherend, and another base material can be used as the other adherend, and these can be bonded together. As the base material (adherent), in addition to the skin layer and base material layer for synthetic simulated leather described later, optical films, optical plates, flexible printed circuit boards, glass substrates, and substrates with ITO vapor-deposited on these substrates, etc. Examples include film-like or sheet-like base materials, as well as metal and non-metal (plastic, glass, etc.) base materials.

The laminate can be manufactured by coating a substrate with a moisture-curable urethane hot-melt resin composition, preferably melted at 80 to 130°C, and curing it with moisture to form a cured material layer. . When the resin composition is used as a hot melt adhesive, the melted resin composition may be applied to one base material, and then the other base material may be bonded thereon and cured by moisture.

The method of coating the moisture-curable urethane hot melt resin composition on the substrate is not particularly limited, and any coating method conventionally used for hot melt adhesives can be used as appropriate. Coating methods include, for example, a comma coating method, a knife coating method, a roll coating method, a screen coating method, a T-die coating method, a fiber coating method, a gravure transfer coating method in which a roll is engraved, and a die coater method with a gear pump. etc.

The laminate of this embodiment can also be configured as synthetic simulated leather, which will be described later. In addition, as mentioned above, the cured layer of the moisture-curable urethane hot melt resin composition used in the laminate has good initial adhesion and abrasion resistance, so it can be used as a base fabric for synthetic simulated leather. Can form a skin layer directly adhered to the material. Therefore, it is possible to provide a synthetic simulated leather having a two-layer structure including a base material such as a base fabric and a skin layer formed of the above-mentioned cured material layer provided on the base material.

Synthetic simulated leather whose skin layer is a cured layer of a moisture-curable urethane hot melt resin composition can be produced, for example, as follows. First, by the above-mentioned coating method, the moisture-curable urethane hot-melt resin composition that forms the skin layer is melted and coated on release paper, a base material such as base fabric is laminated on top of it, and The resin composition is cured to form a cured product layer (skin layer). Then, by peeling it off from the release paper, it is possible to obtain a synthetic simulated leather having a two-layer structure consisting of a base material and a skin layer consisting of a cured material layer provided on the base material. Note that when bonding base materials such as base fabric together, pressure bonding can be performed using, for example, a laminator equipped with a roll or the like. Furthermore, when the resin composition is cured by moisture, it can be aged under predetermined temperature and humidity conditions.

<Synthetic fake leather>
The synthetic simulated leather of one embodiment of the present invention includes a base layer, a skin layer, and an adhesive layer provided between them and bonding them together. In this synthetic simulated leather, the adhesive layer is formed of a cured product layer of the above-mentioned moisture-curable urethane hot-melt resin composition.

Examples of the base fabric constituting the base layer include woven fabrics such as twill weave and plain weave, raised fabrics obtained by mechanically raising cotton fabrics of the woven fabrics, rayon fabrics, nylon fabrics, polyester fabrics, and Kevlar ( (registered trademark) cloth, nonwoven fabrics (polyester, nylon, various latex), various films, sheets, etc. Further, examples of the skin layer include those formed from a paint for forming the skin layer, such as a solution-type urethane resin composition, water-based polyurethane, and thermoplastic polyurethane (TPU).

For example, synthetic simulated leather can be manufactured as follows. First, a paint for forming a skin layer is applied onto a release paper by a known method such as comma coating, knife coating, roll coating, gravure coating, die coating, or spray coating. After appropriately drying the applied paint to form a skin layer, the above-mentioned molten moisture-curable urethane hot melt resin composition is applied onto the skin layer by the above-mentioned coating method, and a base fabric is applied thereon. The base material layers such as the above are pasted together and pressure bonded using a laminator or the like. Thereafter, if necessary, it is aged under predetermined temperature and humidity conditions to form a cured material layer (adhesive layer). Then, by peeling it off from the release paper, the desired synthetic simulated leather can be obtained.

A surface treatment agent may be applied to the surface of the skin layer (including the skin layer made of the cured material layer described in the description of the laminate above) constituting the synthetic simulated leather. By surface treating the epidermis layer with a surface treatment agent, it becomes possible to obtain synthetic fake leather with a quality that is more suitable for commercialization. The synthetic fake leather of this embodiment is suitable as a material constituting shoes, clothing, bags, furniture, vehicle interior materials (for example, instrument panels, doors, consoles, seats), and the like.

Note that, as described above, one embodiment of the present invention may have the following configuration.
[1] Contains a urethane prepolymer having isocyanate groups, which is a reaction product of a polyol component and a polyisocyanate component,
The polyol component includes a high molecular polyol component and a low molecular polyol component,
The polymer polyol component is
Polyester polyol having a structural unit derived from sebacic acid (A1); Polyester polyol having a number average molecular weight of 8,000 or more and having a structural unit derived from 1,4-butanediol and adipic acid (A2) ; and a polyester polyol (A3) having a number average molecular weight of 6,000 or more and having a constitutional unit derived from 1,6-hexanediol and a constitutional unit derived from adipic acid (A3); A) and
at least one polyol (B) selected from the group consisting of a polyester polyol (B1) other than the polyol (A); and a polyether polyol (B2);
The low molecular weight polyol component includes a trifunctional polyol (D) having a molecular weight of 300 or less and having three hydroxyl groups in one molecule,
A moisture-curing urethane in which the ratio of the polyol (A) and the trifunctional polyol (D) satisfies the trifunctional polyol (D) (mmol)/the polyol (A) (g) = 0.14 to 55 mmol/g. Hot melt resin composition.
[2] The moisture-curable urethane hot melt resin composition according to [1] above, wherein the polyol (B) includes a polyol (B _b ) using a plant-derived raw material.
[3] The moisture-curable urethane hot melt resin composition according to [1] or [2] above, wherein the polymer polyol component further contains a polycarbonate polyol (C).
[4] The moisture-curable urethane hot melt resin composition according to [3] above, wherein the polycarbonate polyol (C) contains a polycarbonate polyol (C _b ) using a plant-derived raw material.
[5] The total amount of the polyol (B) and the polycarbonate polyol (C) is greater than the amount of the polyol (A),
The moisture according to [3] or [4] above, wherein the total ratio of the polyol (A), the polyol (B), and the polycarbonate polyol (C) to the total amount of the polyol component is 90% by mass or more. Curable urethane hot melt resin composition.
[6] A laminate comprising a base material and a cured layer of the moisture-curable urethane hot melt resin composition according to any one of [1] to [5] above, provided on the base material.
[7] Comprising a base material layer, a skin layer, and an adhesive layer provided between them and bonding them, wherein the adhesive layer is any one of the above [1] to [5]. Synthetic pseudo-leather which is a cured product layer of the moisture-curable urethane hot-melt resin composition described in .

Hereinafter, the present invention will be specifically explained based on Examples, but the present invention is not limited to these Examples.

<Materials used>
The polymer polyol materials used are shown in Table 1 below.

<Production of moisture-curable urethane hot melt resin composition>
(Example 1)
A polyol component and a polyisocyanate component are placed in a glass reaction container equipped with a stirrer, a thermometer, and a gas inlet, mixed, the inside of the reaction container is heated and depressurized to perform dehydration treatment, and nitrogen gas is then sealed. The reaction was carried out with stirring for 120 minutes at an internal temperature of 100°C. The above polyol component includes a polymer polyol component (100 parts by mass in total) consisting of 10 parts by mass of polyester polyol (A1), 45 parts by mass of polyester polyol (B1-1), and 45 parts by mass of polyether polyol (B2-1). , and 0.5 parts by mass of trimethylolpropane, which is a trifunctional polyol (D) component having a molecular weight of 300 or less, were used. The ratio of polyol (A) to trifunctional polyol (D) was trifunctional polyol (D) (mmol)/polyol (A) (g) = 0.37 mmol/g. For the polyisocyanate component, 22.35 parts by mass of 4,4'-diphenylmethane diisocyanate (MDI) was used, and the molar ratio of NCO groups in MDI to OH groups in the polyol component (NCO group/OH group) was 1.7. And so. In this way, the urethane prepolymer of Example 1 was obtained.

(Examples 2 to 17 and Comparative Examples 1 to 10)
Same as Example 1 except that the type and amount of polyol component used and the amount of polyisocyanate component (MDI) used were changed as shown in the upper row of Table 2 (Tables 2-1 to 2-6) below. Then, urethane prepolymers of each example were obtained. Due to changes in the usage amounts of polyol components and polyisocyanate components, the values of "trifunctional polyol (D)/polyol (A) [mmol/g]" and "NCO group/OH group ( The values of "molar ratio)" are also shown. In addition, regarding Comparative Example 10 with trifunctional polyol (D) (mmol)/polyol (A) (g) = 56.0 mmol/g, it gelled during the stirring reaction and the evaluation described below could not be performed. Ta.

<Evaluation>
The urethane prepolymer obtained in each example was used as the moisture-curable urethane hot melt resin composition (hereinafter sometimes simply referred to as "hot melt resin composition") of each example. We conducted an evaluation. In the evaluation criteria for each item, AA, A, and B are acceptable and good levels, and C is an unacceptable level. The evaluation results are shown in the lower part of Table 2.

(Stability over time in molten state)
The hot melt resin compositions of each example were heated to 100° C. to melt them, and changes in viscosity over time and sedimentation were visually confirmed under conditions of 100° C. for 24 hours. The viscosity of the hot melt resin composition was measured using a BM type viscometer (Tokyo Keiki Seisakusho) with rotor No. Measurements were made under conditions of 4, 30 rpm, and 100°C. The stability of the hot melt resin composition over time in the molten state was evaluated based on the above-mentioned change in viscosity over time (viscosity change rate) and the presence or absence of sediment in accordance with the following evaluation criteria. The viscosity change rate was calculated by viscosity change rate (%)={(viscosity after 24 hours at 100°C−initial viscosity at 100°C)/initial viscosity at 100°C}×100.
AA: No sediment, viscosity change rate less than 20%.
A: There is no sediment, and the viscosity change rate is 20% or more and less than 50%.
B: Precipitation was present, and the viscosity change rate was less than 100%.
C: Precipitation was present, and the viscosity change rate was 100% or more.

(Preparation of evaluation film)
The hot melt resin composition of each example was melted at 100° C. and coated on release paper so that the film thickness after coating was 50 to 70 μm. Thereafter, it was aged for 72 hours in an environment of a temperature of 25° C. and a relative humidity of 60% (60% RH), and further stored at room temperature (20° C.) for 1 day to obtain a film for evaluation with release paper.

(thermal softening point)
Thermal softening point was measured using an evaluation film (width 1.5 cm, length 6 cm) obtained by peeling off the release paper from the evaluation film with release paper. Specifically, as shown in FIG. 1, clips 12 are first attached to the top and bottom of the evaluation film 10, and the clips 12 are further fixed with sellotape (registered trademark). A sample 16 was prepared by attaching a weight 14 that applied a load of cm ² . Note that a 2 cm length of the center of the evaluation film 10 in the longitudinal direction is not covered with Sellotape (registered trademark). Next, as shown in FIG. 2, the clip 12 of the sample 16 without the weight 14 attached was attached to the rotary disk 22 of the gear oven 20. Thereafter, while rotating the rotary disk 22 at 5 rpm, the temperature inside the gear oven 20 was raised from room temperature at a rate of 3° C./min. The temperature (° C.) at which the evaluation film 10 was cut or stretched twice was defined as the thermal softening point. Based on the value of the thermal softening point (° C.), the heat resistance according to the thermal softening point was evaluated according to the following evaluation criteria. The higher the heat softening point, the higher the heat resistance as a film.
A: Thermal softening point is 185°C or higher.
B: Thermal softening point is 170°C or higher and lower than 185°C.
C: Thermal softening point is less than 170°C.

(Alcohol resistance)
The evaluation film obtained by peeling off the release paper from the evaluation film with release paper was cut into 50 mm x 50 mm, and immersed in 25° C. ethanol previously placed in a petri dish for 10 minutes. After 10 minutes, the evaluation film was taken out from the ethanol, the condition of the evaluation film was visually confirmed, and the alcohol resistance was evaluated according to the following evaluation criteria. The following linear swelling rate was calculated by linear swelling rate (%) = (Length of one side of the evaluation film after immersion (mm)/Length of one side of the evaluation film before immersion (50 mm)) x 100. .
AA: The linear swelling rate on one side of the evaluation film is less than 120%.
A: The linear swelling rate on one side of the evaluation film is 120% or more and less than 150%.
B: The linear swelling rate on one side of the evaluation film is 150% or more.
C: The evaluation film is dissolved.

(Initial adhesion)
The hot melt resin composition of each example was heated to 100°C to melt it, and was uniformly coated onto a PET film (width 3 cm) at a coating amount of 100 μm/wet to form a coating layer of the hot melt resin composition. was formed. Immediately after coating, the base fabric (fabric) was crimped using a laminator with a roll temperature of 30° C. and a lamination clearance of 70% of the total thickness of the base fabric, coating layer, and PET film. Ten minutes after bonding, adhesive strength was measured using a digital force gauge (manufactured by Nidec-Shimpo Corporation), and initial adhesiveness was evaluated according to the following evaluation criteria. In addition, if the adhesive strength after 10 minutes of lamination is less than 0.2 kg/3 cm, there is a risk of re-peeling or twisting between the base fabric and the resin layer made of the hot-melt resin composition in the subsequent processing process, resulting in defects. Based on the knowledge that the adhesive strength is 0.2 kg/3 cm or more after 10 minutes of bonding, it is considered to be a pass.
A: Adhesive strength is 0.4 kg/3 cm or more.
B: Adhesive strength is 0.2 kg/3 cm or more and less than 0.4 kg/3 cm.
C: Adhesive strength is less than 0.2 kg/3 cm.

<Preparation of synthetic simulated leather for evaluation>
(1) Preparation of the epidermal layer The epidermal layer of the synthetic fake leather was prepared as follows. First, 100 parts by mass of a solution-type urethane resin (trade name "Rezamin NE-8875-30M", manufactured by Dainichiseika Kagyo Co., Ltd.), a coloring agent (trade name "Seika Seven BS-780 (S) Black", Dainichiseika Kagyo Co., Ltd.) A urethane resin composition for the skin layer was prepared by mixing 10 parts by mass (manufactured by Co., Ltd.) with 25 parts by mass of methyl ethyl ketone (MEK) and 25 parts by mass of dimethyl formamide (DMF) as a diluting solvent. Next, the prepared urethane resin composition was uniformly coated onto the release paper using a bar coater at a coating amount of 250 μm/wet. Thereafter, it was dried at 120° C. for 5 minutes to obtain a skin layer formed on release paper with a thickness of 30 to 50 μm.

(2) Preparation of standard synthetic simulated leather for flexibility evaluation Using the skin layer and adhesive obtained in “(1) Preparation of skin layer” above, standard synthetic simulated leather for flexibility evaluation was prepared as follows. Made leather. First, 100 parts by mass of a solution-type urethane resin (trade name "Rezamin UD-8373BL", manufactured by Dainichiseika Chemical Industries, Ltd.), 12 parts by mass of an isocyanate-based crosslinking agent (trade name "Rezamin NE", manufactured by Dainichiseika Chemical Industries, Ltd.), An adhesive was prepared by mixing 30 parts by mass of methyl ethyl ketone (MEK) and 30 parts by mass of dimethylformamide (DMF) as a diluting solvent. Next, the prepared adhesive was applied to the skin layer on the release paper obtained in "(1) Preparation of skin layer" above to a dry film thickness of about 100 μm, and the adhesive coating was was formed. After removing the solvent in the adhesive coating layer by heating, immediately remove the base fabric (fabric) at a roll temperature of 40°C and the lamination clearance between the base fabric, coating layer (adhesive layer), skin layer, and release paper. Pressure bonding was carried out using a laminator set to 70% of the total thickness. Thereafter, after aging at 50° C. for 48 hours to harden the coating layer and form an adhesive layer, the release paper in contact with the skin layer was peeled off to obtain a standard synthetic fake leather.

(3) Preparation of synthetic simulated leather of each example Using the skin layer obtained in "(1) Preparation of skin layer" above and the hot melt resin composition of each example, the synthetic simulated leather of each example was prepared as follows. was created. First, a hot-melt resin composition is heated to 100°C to melt it, and the molten hot-melt resin composition is applied to the skin layer on the release paper obtained in "(1) Preparation of skin layer" above to a dry thickness of about 100 μm. The hot melt resin composition was coated to form a coated layer of the hot melt resin composition. Immediately after coating, the base fabric (textile) is rolled at a roll temperature of 30°C and a lamination clearance of 70% of the total thickness of the base fabric, coating layer (hot melt resin composition layer), skin layer, and release paper. It was crimped using a laminator. Thereafter, after aging at 25° C. and 60% RH for 48 hours to form a cured layer of the hot melt resin composition, the release paper in contact with the skin layer was peeled off. In this way, a synthetic pseudo-leather was obtained in which the base fabric (fabric) as the base material layer and the skin layer were adhered via the cured product layer of the hot melt resin composition as the adhesive layer.

(cold resistance flexibility)
A test sheet with a width of 50 mm and a length of 150 mm (evaluation range of 100 mm) was prepared for each example of synthetic simulated leather. Using the prepared test sheet, it was tested using a Dematcher Flexing Tester (model number "No. 119-L DEMATTIA FLEXING TESTER", manufactured by Yasuda Seiki Seisakusho Co., Ltd.) in an environment of -10°C, with an expansion/contraction bending range of 72% to 108%, and a low temperature of -10°C. A bending test was conducted below. Then, the cold resistance flexibility was evaluated according to the following evaluation criteria.
AA: No cracking after 60,000 cycles.
A: No cracking after 30,000 cycles, but cracks after 60,000 cycles.
B: No cracking after 10,000 cycles, cracking by 30,000 cycles.
C: Cracking after 10,000 cycles.

(Hydrolysis resistance)
For each example of synthetic simulated leather, the adhesive strength before the hydrolysis resistance test and the adhesive strength after the hydrolysis resistance test were measured, and the hydrolysis resistance was evaluated by comparing them. Specifically, a hot melt tape was pressed onto the upper surface of the skin layer of the synthetic fake leather using an iron at 140°C for 1 minute, and after cooling at room temperature (20°C) for 1 hour, the base fabric of the synthetic fake leather and The skin layer adhering to the hot melt tape was peeled off in a 180° direction at a peeling speed of 200 mm/min, and its strength was tested using a tensile tester (model name "Autograph AGS-100A", manufactured by Shimadzu Corporation). The adhesive strength was measured.
On the other hand, the synthetic simulated leather of each example was placed in a constant temperature bath at 70° C. and 95% RH for a predetermined period of time, and then the adhesive strength after the hydrolysis resistance test was measured in the same manner as above. The adhesive strength before the test and the adhesive strength after the test were compared, and the hydrolysis resistance was evaluated according to the following evaluation criteria. Note that the retention rate of adhesive strength means the ratio of the adhesive strength after being stored in the tank for a predetermined period to the adhesive strength before being placed in the tank.
AA: The adhesive strength retention rate after 8 weeks of storage is 70% or more.
A: The retention rate of adhesive strength after storage for 5 weeks is 70% or more.
B: The retention rate of adhesive strength after storage for 5 weeks is 50% or more and less than 70%.
C: The retention rate of adhesive strength after storage for 5 weeks is less than 50%.

(Flexibility)
Each synthetic imitation leather and the standard synthetic imitation leather obtained in "(2) Preparation of standard synthetic imitation leather for flexibility evaluation" above were compared by touch, and the following results were obtained based on the standard synthetic imitation leather: Flexibility was evaluated according to the evaluation criteria.
AA: Much softer than standard synthetic leather.
A: Softer than standard synthetic fake leather.
B: Soft as standard synthetic leather.
C: Significantly harder than standard synthetic leather.

(wear resistance)
The hot melt resin composition of each example was heated to 100°C to melt it, and the molten hot melt resin composition was applied onto a release paper to a dry film thickness of about 100 μm. A layer was formed. Immediately after coating, the base fabric (woven fabric) is placed in a laminator with a roll temperature of 30°C and a lamination clearance of 70% of the total thickness of the base fabric, coating layer (hot melt resin composition layer), and release paper. It was crimped. Thereafter, after aging at 25° C. and 60% RH for 48 hours to form a cured layer of the hot melt resin composition, the release paper in contact with the cured layer was peeled off. In this way, synthetic fake leather was produced as a two-layered laminate comprising a base fabric (fabric) and a skin layer made of a cured product layer of a hot melt resin composition provided on the base fabric. . This was used as a synthetic simulated leather for the abrasion resistance test described below.

A circular test piece with a diameter of 11.5 cm was prepared for each synthetic simulated leather for abrasion resistance test. Using this test piece and a Taber abrasion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), a wear resistance test was conducted under the conditions of a load of 500 g, a rotation speed of 60±2 rpm, and a wear wheel CS-10. Then, the wear resistance was evaluated according to the following evaluation criteria.
AA: No change in appearance such as scratches after 1500 cycles.
A: There was no change in appearance such as scratches after 1000 times, but there were changes in appearance such as scratches by 1500 times.
B: No change in appearance such as scratches after 500 times, but change in appearance such as scratches by 1000 times.
C: Appearance changes such as scratches after being used less than 500 times.

<Heat resistance (heat resistance creep test)>
As a creep test, a test was conducted in which a constant load was applied to a test piece at high temperature for a long period of time, and the amount of deformation and time until breakage were measured. Specifically, the following steps 1) to 8) were performed.
1) The hot-melt resin composition and coating rod of each example to be tested were placed in an oven at 100° C. and preheated.
2) Apply a hot melt resin composition to the polyurethane (PU) resin layer surface of the wet film forming fabric (A) at 200 μGap (thickness 200 μm) and immediately bond it to the PU resin layer surface of the wet film forming fabric (B). I did it.
The wet film-forming fabric (A) and the wet film-forming fabric (B) were prepared by applying a polyurethane resin solution (trade name "Lezamin CU-4340NS") (resin solid content: 30 A PU resin layer is formed by applying a solution (mass%, manufactured by Dainichiseika Kogyo Co., Ltd.) diluted with DMF to a solid content of 15% by mass, coagulating and removing DMF in a water tank, and then drying. Synthetic pseudo-leather was used, in which a porous layer having a thickness of 800 to 1000 μm after drying was formed on the base material.
3) After curing the above bonded product at 25° C./60% RH for 24 hours, heat resistance was measured according to the following procedure.
4) The oven was set at 170°C. Further, the bonded product was cut to a width of 3 cm and a length of 12 cm or more to prepare a test piece.
5) The ends of the test piece were peeled off at the bonded surface, clamps were attached and fixed to the wet film forming fabric (A) side and the wet film forming fabric (B) side, respectively, and a 3 kg weight was hung on one side.
6) After hanging the test sample in an oven at 170°C, the oven door was quickly closed.
7) After closing the door, leave it for 5 minutes.
8) After 5 minutes had passed, the test piece was immediately taken out and left at 170°C for 5 minutes to observe the peeled length and peeled state, and the heat resistance was evaluated according to the following evaluation criteria.
A: The peeled length is less than 2 cm, and the peeled state is substrate destruction.
B: The peeled length is 2 cm or more and less than 5 cm, and the peeled state is substrate destruction.
C: The peeled length is 5 cm or more, or the peeled state is peeling of the PU resin surface.

10 Evaluation film 12 Clip 14 Weight 16 Sample 20 Gear oven 22 Turntable

Claims

Contains a urethane prepolymer having isocyanate groups, which is a reaction product of a polyol component and a polyisocyanate component,
The polyol component includes a high molecular polyol component and a low molecular polyol component,
The polymer polyol component is
Polyester polyol having a structural unit derived from sebacic acid (A1); Polyester polyol having a number average molecular weight of 8,000 or more and having a structural unit derived from 1,4-butanediol and adipic acid (A2) ; and a polyester polyol (A3) having a number average molecular weight of 6,000 or more and having a constitutional unit derived from 1,6-hexanediol and a constitutional unit derived from adipic acid (A3); A) and
at least one polyol (B) selected from the group consisting of a polyester polyol (B1) other than the polyol (A); and a polyether polyol (B2);
The low molecular weight polyol component includes a trifunctional polyol (D) having a molecular weight of 300 or less and having three hydroxyl groups in one molecule,
A moisture-curing urethane in which the ratio of the polyol (A) and the trifunctional polyol (D) satisfies the trifunctional polyol (D) (mmol)/the polyol (A) (g) = 0.14 to 55 mmol/g. Hot melt resin composition.
The moisture-curable urethane hot melt resin composition according to claim 1, wherein the polyol (B) includes a polyol ( Bb ) using a plant-derived raw material.
The moisture-curable urethane hot melt resin composition according to claim 1, wherein the polymeric polyol component further contains a polycarbonate polyol (C).
The moisture-curable urethane hot melt resin composition according to claim 3, wherein the polycarbonate polyol (C) includes a polycarbonate polyol ( Cb ) using a plant-derived raw material.
The total amount of the polyol (B) and the polycarbonate polyol (C) is greater than the amount of the polyol (A),
The moisture-curable urethane hot melt according to claim 3, wherein the total ratio of the polyol (A), the polyol (B), and the polycarbonate polyol (C) to the total amount of the polyol component is 90% by mass or more. Resin composition.
base material and
A laminate comprising: a cured product layer of the moisture-curable urethane hot melt resin composition according to any one of claims 1 to 5, provided on the base material.
Comprising a base material layer, a skin layer, and an adhesive layer provided between them and bonding them together,
A synthetic simulated leather, wherein the adhesive layer is a cured product layer of the moisture-curable urethane hot melt resin composition according to any one of claims 1 to 5.