JP2025082571A - Two-liquid type urethane resin composition for synthetic leather and synthetic leather - Google Patents

Abstract

To provide a two-liquid type urethane resin composition for synthetic leather, which is quickly hardened when a liquid main agent and a liquid hardener are mixed at room temperature and enables an urethane resin coat applied on a surface of a synthetic leather to be formed so as to have a state of excellent peeling-resisting strength and flexibility, and also to create a synthetic leather having excellent peeling-resisting strength and flexibility using the same.SOLUTION: A two-liquid type urethane resin composition consists of a main agent containing a polyol compound and a chain extender, and a hardener containing an isocyanate compound. The polyol compound is a liquid polyol compound including 1 to 15 mass% of autocatalytic amine-based polyol containing two or more tertiary amine groups and three or more hydroxyl groups in 100 mass% of the polyol compound in the two-liquid type urethane resin composition for synthetic leather.SELECTED DRAWING: None

Description

This invention relates to a two-component urethane resin composition for synthetic leather and synthetic leather made using the same.

Generally, synthetic leather, which is used for automobile seats, sports shoes, etc., is produced by overlaying and integrating a resin layer onto a knitted or woven base fabric.
Artificial leather, which has a similar structure to synthetic leather, uses a nonwoven fabric soaked in resin liquid as a base fabric, but the structure in which a resin layer is laminated and integrated onto the surface of the base fabric is common to synthetic leather, so in this invention, artificial leather is also referred to as synthetic leather.

Two-component urethane resins used in the resin layer of such synthetic leathers include those that are environmentally friendly because they use bio-polyols and bio-chain extenders. One known example is a urethane resin-based prepolymer for synthetic leather that can be applied to the base fabric immediately after instantaneous heating and mixing of a prepolymer and a polyol in a mixer without using organic solvents (Patent Document 1).

In addition, a catalyst is used to promote the reaction between the polyol, which is the main component of the two-component urethane resin, and the isocyanate, which is the hardener component. Known catalysts include tertiary amine compounds, amines having an isocyanate-reactive group, and autocatalytic polyols based on amine initiators containing tertiary amine groups (Patent Document 2, paragraph 0068).

The above-mentioned autocatalytic amine-based polyol is a polyol that is a main component and has a catalytic function added thereto. For example, it is a polyol compound that has a functionality of 2 to 8, a hydroxyl value of 15 to 200, and at least one tertiary amine group, which imparts an autocatalytic function, and is known to be used in the production of flexible polyurethane foams (Patent Document 3).

Patent No. 7295539 Special Publication No. 2003-533565 Special Publication No. 2007-535606

However, in the case of two-component urethane resin for synthetic leather as described in the above-mentioned Patent Document 1, the polyol (OH) component and the isocyanate (NCO) component are heated separately or in a mixed state to lower the viscosity and react when preparing the prepolymer, which requires a lot of heat energy. In addition, after the urethane resin is applied, a lot of heat energy and time is consumed for drying and curing, and the amount of filler that can be added is also limited, making it difficult to reduce costs.

To manufacture synthetic leather using the above-mentioned urethane resin-based prepolymer, a catalyst must be used just before the polyurethane resin is applied to the base fabric, and the prepolymer and polyol must be mixed in an instantaneous mixer to cause the OH and NCO components to react quickly. However, depending on the type and amount of catalyst used, the synthetic leather may become prone to bleed (discoloration) and its physical properties may deteriorate.

Furthermore, the autocatalytic amine polyols shown in Patent Documents 2 and 3 contain an unspecified amount, 2 to 100% by weight, of a polyol having a hydroxyl value of 15 to 200 in 100% by weight of a foamable polyol composition, and cannot be said to be applicable to synthetic leather in terms of foaming, peel strength, unity, etc.
In other words, the use of such an autocatalytic amine polyol to formulate a two-component urethane resin for synthetic leather has not been anticipated in the past, and even if it were accidentally used, it is not easy to adjust the heating temperature without impairing the quality in order to adjust the pot life for application to a base fabric or release paper, making it difficult to consistently obtain synthetic leather of environmentally friendly quality that has the required flexibility and peel strength resistance.

The object of this invention is to provide a two-component urethane resin composition that solves the above problems and can reduce the component ratio of prepolymer, which requires a large amount of thermal energy for production, to 50% or less in the resin composition, and that allows the curing reaction to proceed quickly by simply mixing the liquid base agent and curing agent at room temperature without the need for a large amount of catalyst, and that provides a two-component urethane resin composition for synthetic leather that provides a urethane resin coating of synthetic leather with excellent peel strength and flexibility, or to provide synthetic leather using the two-component urethane resin composition.

In order to solve the above problems, the present invention provides a two-liquid type urethane resin composition for synthetic leather, which is characterized in that the main component is a mixture of a polyol compound and a chain extender, and the curing agent contains an isocyanate compound, and the polyol compound is a liquid polyol compound that contains 1 to 15 mass % of an autocatalytic amine-based polyol containing two or more tertiary amine groups and three or more hydroxyl groups per 100 mass % of the polyol compound, and the synthetic leather using the same.

The above-mentioned autocatalytic amine-based polyol is preferably an amine-based polyether polyol having a hydroxyl value of 300 to 1000 KOHmg/g, which is obtained by addition polymerization of propylene oxide (PO) or propylene oxide (PO) and ethylene oxide (EO) together with one or more amines selected from ethylenediamine, diethylenetriamine, toluenediamine, and tetraethylenepentamine.

In the two-component urethane resin composition for synthetic leather of the present invention constituted as described above, the liquid polyol compound contained in the base contains a predetermined amount of a specific autocatalytic amine-based polyol in the polyol compound, so that simply by mixing with a curing agent at room temperature, the liquid polyol and the chain extender react quickly.
Therefore, there is less need to react polyol and isocyanate in advance to form a prepolymer, and the component ratio of the prepolymer in the resin composition can be reduced to 50% or less, resulting in a two-component urethane resin composition that contributes to power saving and process reduction.

In addition, the reaction rate of the amine-based polyol containing two or more tertiary amine groups and three or more hydroxyl groups is appropriate, so it has an appropriate pot life when producing synthetic leather, and since no organic solvent is required for viscosity adjustment, the drying and curing time of the two-component urethane resin composition is shortened and the heat energy consumed in the manufacturing process is also significantly reduced.

The two-component urethane resin composition of this invention has a low-viscosity liquid base and hardener, so it is possible to use a large amount of relatively inexpensive filler when manufacturing synthetic leather. In addition, the minimum amount of catalyst required is small, so bleeding and deterioration of the physical properties of the synthetic leather are also suppressed.

When the base agent is a base agent containing a biopolyol or a biochain extender, or both, the two-component urethane resin composition is more resource-saving and environmentally friendly. Furthermore, it is preferable to add a filler such as a biofiller to the base agent in order to make the two-component urethane resin composition more environmentally friendly as described above.

Furthermore, by setting the R value, which is the equivalent ratio (isocyanate group/hydroxyl group) of the two-component urethane resin composition, to 1.0 to 1.4, the physical properties such as the required pot life for application to a base fabric or release paper as synthetic leather are stabilized.
Furthermore, the synthetic leather having a base fabric surface coated with the above-mentioned two-liquid type urethane resin composition has the required quality characteristics such as flexibility and peel strength more stably.

The liquid polyol compound of this invention contains a predetermined amount of a predetermined autocatalytic amine polyol, so there is no need to prepare a large amount of prepolymer in advance, which requires a lot of heat energy for production. For example, even if the prepolymer component ratio is 50 mass% or less, the reactivity is excellent, and the liquid base agent and curing agent can be mixed at room temperature without heating using a small amount of catalyst as necessary, and the curing reaction occurs quickly. When applied to the surface of synthetic leather, it becomes a two-liquid urethane resin composition for synthetic leather that produces a urethane resin coating with excellent peel strength and flexibility, and furthermore, by using this, synthetic leather with excellent peel strength and flexibility can be obtained.

The two-component urethane resin composition for synthetic leather, which is an embodiment of this invention, and the raw materials for synthetic leather using the composition, their blending ratios, and manufacturing conditions are described in detail below. Note that the abbreviations for chemical components are given in parentheses after their general names as necessary.

<Autocatalytic amine-based polyol>
The autocatalytic amine-based polyol used in the present invention has two or more tertiary amine groups (sometimes also referred to as N groups) and three or more hydroxyl groups, preferably has a hydroxyl value of 300 to 1000 KOHmg/g, and is preferably an amine-based polyether polyol.

Specific examples of amine-based polyols include those obtained by addition polymerization of propylene oxide (PO) and/or ethylene oxide (EO) to one or more amines selected from ethylenediamine, diethyltriamine, toluenediamine, and tetraethylenepentamine, and examples of commercially available products obtained by addition polymerization of PO or PO and EO together, such as Sannix manufactured by Sanyo Chemical Industries, Ltd.; NP-300, NL-300, NL-270, NE-240, and AP-470.

These amine-based polyols are multifunctional polyols containing tertiary amine groups, have excellent reactivity with isocyanates, and are cured in an extremely short time, making them the main component from which high-strength urethane resins can be obtained.
In order to obtain such properties, it is more preferable that the amine-based polyol has two or more tertiary amine groups and 3 to 7 hydroxyl groups.

The amount of autocatalytic amine polyol added is preferably 1 to 15% by mass of the OH component, and more preferably 1 to 5% by mass. This is because if it is less than 1% by mass, the desired effect is not sufficient, and if it exceeds 15% by mass, the resin becomes hard and does not have sufficient flexibility, and the usable time is also shortened.

If the hydroxyl value is less than 300 KOHmg/g, the reactivity will be insufficient and it will be difficult to quickly peel off from the release paper, and if it exceeds 1000 KOHmg/g, the resin will become hard and its flexibility will be poor.

<Liquid polyol>
The liquid polyol used in the present invention is preferably one or more polyols selected from polyester polyols, polyether polyols, polycarbonate polyols, lactone polyols, and castor oil polyols which are liquid at room temperature.
Incidentally, the normal temperature in this invention refers to the normal temperature defined by the Japanese Industrial Standards (JIS Z 8703), which is in the range of 20° C.±15° C. (5 to 35° C.).

<Chain lengthener (also called chain extender)>
The chain extender used in the present invention is preferably one or more selected from ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol (1,3PDO), 3-methyl-1,5-pentanediol (MPD), 2-methyl-1,3-propanediol (MPO), etc., which are liquid at room temperature. However, such chain extenders are used selectively depending on the application and purpose of the synthetic leather.

<Isocyanate>
Specific examples of the isocyanate used in the present invention include 4,4'-diphenylmethane diisocyanate (MDI), carbodiimide-modified MDI (liquid MDI), 2,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated MDI, and the like. Dimers and trimers thereof may also be used, and two or more of these may also be used in combination.

<Additive-1>
Specific examples of additives that may be used as necessary in the present invention include antioxidants, ultraviolet absorbers, weather resistance agents, viscosity reducers, thickeners, thixotropy-imparting agents, flame retardants, silicone foam stabilizers, foaming agents, antistatic agents, hydrolysis inhibitors, plasticizers, retarders, moisture absorbents, and coupling agents.

<Additive-2>
Other additives include calcium carbonate, aluminum hydroxide, talc, and other biofillers such as eggshell powder, shell powder, apple powder, wood powder (cellulose), glass balloons (hollow foams), microsphere powder foams, and diatomaceous earth, which have an average particle size of 100 μm or less and are highly dispersible. Two or more of these can also be used in combination. As such additives (fillers), it is preferable to use biofillers, which are particularly environmentally friendly additives. For example, biofillers derived from eggshell powder and mainly composed of calcium carbonate (CaCO ₃ ), and recycled biofillers can be used. An example of commercially available eggshell powder is eggshell powder (without egg membrane, average particle size 15 μm) manufactured by Green Techno 21 Co., Ltd.

The amount of additive-2 such as calcium carbonate can be 10 to 200 parts by mass per 100 parts by mass of the OH component, with a preferred amount being 30 to 80 parts by mass. This amount can be adjusted within the range that the instantaneous mixer can tolerate, but adding an excessive amount is not preferred as it will harden the synthetic leather and impair its flexibility or flexibility.

<Catalyst>
The catalyst used in the present invention is preferably an amine-based catalyst including an acid-blocked type and a temperature-sensitive thermal dissociation type, and it is preferable to select and use one or more of these. Commercially available products of such catalysts include U-CAT (registered trademark, manufactured by San-Apro Co., Ltd.) SA102, which is a DBU-octylate salt that extends the pot life, and U-CAT (registered trademark, manufactured by San-Apro Co., Ltd.) 1102, which is a DBN-octylate salt.

<Composition and manufacturing conditions>
(a) Polyol component Liquid polycarbonate has good hydrolysis resistance, and liquid polyether polyol has good low-temperature flexibility, and these can be selected and combined according to the application. In addition, since the manufacturing process involves only mixing, including the liquid chain extender, a combination with good compatibility is preferred.

(b) Isocyanate Component The isocyanate compound is preferably liquid 4,4'-diphenylmethane diisocyanate (MDI) or a prepolymer with an NCO% of 7 to 30%. When the NCO% of a prepolymer with an NCO group content of 7 to 30% is less than 7%, the viscosity increases and the reactivity decreases. When the NCO% is 30% or more, the prepolymer becomes hard and the flexibility decreases. The prepolymer component ratio in the resin component is preferably 0 to 50%. When liquid MDI is used instead of the prepolymer, the viscosity decreases and the curing property improves, but the prepolymer becomes slightly hard and the flexibility decreases slightly.

(c) R value [(isocyanate group/hydroxyl group) equivalent ratio]
The R value is preferably in the range of 1.0 to 1.4, because if it is less than 1.0, the reactivity is slow and the physical properties are insufficient, and if it exceeds 1.4, the resin becomes hard and the flexibility is poor.

(d) Liquid temperature: The liquid is used at room temperature (e.g., 25° C.), but it can be heated up to 50° C. as necessary. However, as the temperature increases, the viscosity decreases, but the pot life becomes shorter, and the amount of catalyst required must be reduced.

(e) Curing time The curing time used in this invention is the total time including pre-drying and post-drying. Pre-drying is performed under conditions that give the material a moderate tackiness and a semi-cured state that does not penetrate the base fabric. Usually, a curing time of 2 minutes at 120°C is used as a guideline, and the amount of catalyst is adjusted so that the curing time is 2 to 3 minutes at 120 to 130°C.
The post-drying is carried out so that the pattern does not collapse and sufficient physical properties can be obtained even when the release paper is peeled off after laminating the base fabric.

The polyol (OH) components (Production Examples 1-4) and isocyanate (NCO) components (Production Examples 5-6) used as the base resin were produced in the blending ratios shown in Tables 1 to 3 below, and comparative prepolymers (OH-R1, OH-R2) were also produced.
The raw materials used in the above production are listed below, with the abbreviations shown in Table 1-3 in brackets [ ]. Note that OHV shown below is the hydroxyl value, its unit is KOHmg/g, and f is the number of functional groups.

(1) Bio-liquid polyether polyol (SK Chemicals Co., Ltd.; ECOTRION H-2000, bifunctional (2f), hydroxyl value (OHV) = 56) [H-2000]
(2) Liquid polyether polyol (Sanyo Chemical Industries, Ltd.; Sannix PP-1000, 2f, OHV=112) [PPG-1000]
(3) Bio-liquid chain extender (DuPont; 1,3PDO, 2f, OHV=112) [1,3PDO]
(4) 4,4'-diphenylmethane diisocyanate [MDI]
(5) Autocatalytic amine polyol (ethylenediamine PO addition polyol, Sanyo Chemical Industries, Ltd.; Sannix NP-300, 4f, OHV=750) [NP-300]
(6) Autocatalytic amine polyol (diethylenetriamine PO adduct polyol, Sanyo Chemical Industries, Ltd.; Sannix NP-400, 5f, OHV=700) [NP-400]
(7) Liquid polycarbonate dipolyol (Kuraray Co., Ltd.; C-2090, 2f, OHV=56) [C-2090]
(8) Liquid polyester dipolyol (Kuraray Co., Ltd.; P-2010, 2f, OHV=56) [P-2010]
(9) Liquid castor oil-based polyol (Toyokuni Oil Mills; HS CM-025P, 3f, OHV=200) [HS CM-025P]
(10) Carbodiimide-modified liquid MDI (Mitsui Chemicals; Cosmonate LL) [liquid MDI]

(Production Example 1; OH-1a)
The above (1) bio liquid polyether polyol [H-2000], (2) liquid polyether polyol [PPG-1000], (3) bio liquid chain extender [1,3PDO], and (5) amine polyol [NP-300] were mixed uniformly at room temperature for 15 minutes in the blending ratio shown in Table 1 to produce an OH component mixture "OH-1a" with an OHV of 115.72.

(Production Example 2; OH-1b)
In the blending ratio shown in Table 1, (1) bio liquid polyether polyol [H-2000], (2) liquid polyether polyol [PPG-1000], (3) bio liquid chain extender [1,3PDO], and (6) amine-based polyol [NP-400] were uniformly stirred at room temperature for 15 minutes to produce an OH component mixture "OH-1b" with an OHV of 119.88.

(Production Example 3; OH-2a)
In the blending ratio shown in Table 1, (7) liquid polycarbonate dipolyol [C-2090], (8) liquid polyester dipolyol [P-2010], (9) liquid castor oil-based polyol [HS CM-025P], (3) bio liquid chain extender [1,3 PDO], and (5) amine-based polyol [NP-300] were uniformly stirred at room temperature for 15 minutes to produce an OH component mixture "OH-2a" with an OHV of 139.72.

(Production Example 4; OH-2b)
In the blending ratio shown in Table 1, (7) liquid polycarbonate dipolyol [C-2090], (8) liquid polyester dipolyol [P-2010], (9) liquid castor oil-based polyol [HS CM-025P], (3) bio liquid chain extender [1,3 PDO], and (6) amine-based polyol [NP-400] were uniformly stirred at room temperature for 15 minutes to produce an OH component mixture "OH-2b" with an OHV of 131.00.

(Production Example 5; NCO-1)
In the blending ratio shown in Table 1, (8) liquid polyester dipolyol [P-2010] kept at 60°C was added to (4) 4,4'-diphenylmethane diisocyanate [MDI] kept at 60°C, and the mixture was stirred at 80°C for 2 hours. After that, (10) carbodiimide-modified liquid MDI [liquid MDI] was added and the mixture was stirred at 80°C for 1 hour to produce an isocyanate component "NCO-1" with an NCO% of 22.35%.

(Production Example 6; NCO-2)
In the blending ratio shown in Table 1, (1) bio liquid polyether polyol [H-2000] and (2) liquid polyether polyol [PPG-1000] were mixed uniformly at 60°C and stirred, and (4) 4,4'-diphenylmethane diisocyanate [MDI] kept at 60°C was added, and the mixture was stirred at 80°C for 3 hours to produce an isocyanate component "NCO-2" with an NCO content of 10.08%.

(Prepolymer: OH-R1)
In the ratio shown in Table 1, (1) bio liquid polyether polyol [H-2000] and (2) liquid polyether polyol [PPG-1000] were mixed uniformly at 60°C and stirred, and (4) 4,4'-diphenylmethane diisocyanate [MDI] kept at 60°C was added and stirred for 2 hours at 80°C. After that, (3) bio liquid chain extender [1,3PDO] was added and reacted at 80°C for 1 hour to produce OH type prepolymer "OH-R1" with OHV = 71.60.

(Prepolymer: OH-R2)
In the ratio shown in Table 1, (7) liquid polycarbonate dipolyol [C-2090], (8) liquid polyester dipolyol [P-2010], and (9) liquid castor oil-based polyol [HS CM-025P] were mixed and stirred at 60°C, (4) 4,4'-diphenylmethane diisocyanate [MDI] kept at 60°C was added, and the mixture was stirred at 80°C for 2 hours. After that, (3) bio liquid chain extender [1,3PDO] was added and reacted at 80°C for 1 hour to produce OH-type prepolymer "OH-R2" with OHV = 96.99.

Next, Examples 1-5 and Comparative Example 1 of the two-liquid urethane resin composition for synthetic leather of the present invention were produced using the raw materials (OH components, catalyst, and base material containing filler, and NCO components) and the blending ratios (parts by mass) shown in Table 2 below, and synthetic leather for sports shoes was produced using Examples 1-5. Note that the filler (CaCO ₃ ) used was a biofiller derived from eggshell powder.

The instantaneous mixer used in the examples and comparative examples has a well-known structure, as described in Patent Document 1, and is a device that instantly and uniformly mixes each liquid supplied to a multi-stage impeller rotating at high speed inside a cylinder, and the resulting mixture can be discharged from a mixing head.

Table 2 lists the manufacturing conditions (composition of ingredients, temperature conditions, etc.) and the evaluation of the physical properties of the synthetic leather. The physical properties of the synthetic leather, "peel strength (kg/cm) and bending durability at room temperature," were measured using a flexometer in accordance with the test method of JIS K6545.

[Example 1]
The polyol compound (OH-1a, liquid temperature 25°C) of Production Example 1 and a tertiary amine catalyst (SA1102, temperature-sensitive catalyst, manufactured by San-Apro Co., Ltd.) were mixed and stirred as the main component as the OH component, and NCO-2 (25°C) of Production Example 6 was added as the curing agent (NCO component) and mixed and stirred with an instantaneous mixer, and 400 g/ ^m2 was applied to release paper with a skin for sports shoes with a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and dried at 120°C for 10 minutes. The release paper was then peeled off to produce synthetic leather for sports shoes.

[Example 2]
The base material was a mixture of the polyol compound (OH-1a, liquid temperature 25°C) from Production Example 1 as the OH component, calcium carbonate ( _CaCO3 ) as the filler, and a tertiary amine catalyst (SA1102, temperature-sensitive catalyst, manufactured by San-Apro Co., Ltd.), and NCO-2 (25°C) from Production Example 6 was added as the curing agent (NCO component) and mixed and stirred with an instantaneous mixer. The mixture was then applied to release paper with a skin for sports shoes at 400 g/ ^m2 with a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and post-dried for 9 minutes at 120°C. The release paper was then peeled off to produce synthetic leather for sports shoes.

[Example 3]
The polyol compound (OH-1b, liquid temperature 25°C) of Production Example 2 and a tertiary amine catalyst (SA1102, temperature-sensitive catalyst, manufactured by San-Apro Co., Ltd.) were mixed and stirred as the main component as the OH component, and NCO-2 (25°C) of Production Example 6 was added as the curing agent (NCO component) and mixed and stirred with an instantaneous mixer, and 400 g/ ^m2 was applied to release paper with a skin for sports shoes with a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and post-dried for 7 minutes at 120°C. The release paper was then peeled off to produce synthetic leather for sports shoes.

[Example 4]
The polyol compound (OH-1b, liquid temperature 25°C) from Production Example 2 as the OH component, calcium carbonate ( _CaCO3 ) as a filler, and a tertiary amine catalyst (SA1102, temperature-sensitive catalyst, manufactured by San-Apro Co., Ltd.) were mixed and stirred to form the main component, and NCO-2 (25°C) from Production Example 6 was added as the curing agent (NCO component) and mixed and stirred with an instantaneous mixer, and 400 g/ ^m2 was applied to release paper with a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and post-dried for 6 minutes at 120°C. The release paper was then peeled off to produce synthetic leather for sports shoes.

[Example 5]
The OH component was prepared by mixing and stirring the polyol compound (OH-1a, liquid temperature 25°C) from Production Example 1, calcium carbonate (CaCO ₃ ) as a filler, and a tertiary amine catalyst (SA1102, temperature-sensitive catalyst, manufactured by San-Apro Co., Ltd.) as the base material, and carbodiimide-modified liquid MDI (Cosmonate LL, NCO 29.0%, manufactured by Mitsui Chemicals Co., Ltd.) as a curing agent (NCO component) was added and mixed and stirred with an instantaneous mixer, and 400 g/m ² was applied to release paper with a skin for sports shoes using a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and dried at 120°C for 5 minutes. The release paper was then peeled off to produce synthetic leather for sports shoes.

[Comparative Example 1]
As the OH component, the above-mentioned (prepolymer: OH-R1, liquid temperature 50°C), tertiary amine catalyst (Air Products; 33LV) and tertiary amine catalyst (San-Apro; SA1102, temperature-sensitive catalyst) were mixed and stirred to form the main component, and NCO-2 (25°C) from Production Example 6 was added as the curing agent (NCO component), and the mixture was mixed and stirred with an instantaneous mixer, and 400 g/ ^m2 was applied to release paper with a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and post-dried for 98 minutes at 120°C. The release paper was then peeled off to produce synthetic leather for sports shoes.

As is clear from the polyol components in Table 1 and the test results shown in Table 2, Examples 1 to 5, which used polyols containing 2 to 5 mass% of autocatalytic amine polyol (Production Examples 1 and 2), hardened in 7 to 12 minutes at room temperature despite having a small amount of tertiary amine catalyst and a component ratio of prepolymer of less than 50%, and the resin coating of the synthetic leather obtained had a peel strength of 4.2 kg/cm or more, which is sufficient for sports shoes, and also showed durability of more than 150,000 bending cycles at room temperature. From these facts, Examples 1 to 5 were evaluated as two-component urethane resin compositions for synthetic leather that can be used with environmentally friendly raw materials and production conditions to obtain high-quality synthetic leather that is sufficiently durable and practical for sports shoes.

Next, Examples 6-10 and Comparative Example 2 of the two-component urethane resin composition for synthetic leather of the present invention were produced using the blending ratios (parts by mass) of the raw materials shown in Table 3 below, and further synthetic leather for automobiles or furniture was produced using Examples 6-10.
In Table 3, the production conditions (composition of ingredients, temperature conditions, etc.) and the physical properties of the synthetic leather are also shown.

Among the physical property evaluations of the above synthetic leather, the "peel strength" and "room temperature bending property" were the results obtained by carrying out the test methods shown in Table 2.
In addition, the hydrolysis resistance test was performed using the Jungle Test, in which synthetic leather test pieces were exposed to a high temperature and humidity environment of 70°C and 95% humidity for 4 weeks. Those that showed no deterioration, were of good quality, and had a property retention rate of 80% or more were rated as good.

[Example 6]
As the OH component, the polyol compound of Production Example 3 (OH-2a, liquid temperature 25°C) and a tertiary amine catalyst (manufactured by San-Apro Co., Ltd.; SA1102, temperature-sensitive catalyst) were mixed and stirred to form the main component, and NCO-1 (25°C) of Production Example 5 was added as the curing agent (NCO component), and the mixture was mixed and stirred with an instantaneous mixer, and applied to 250 g/ ^m2 of automotive release paper with skin using a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a knit base fabric for automobiles was placed on top of it and post-dried for 7 minutes at 120°C. The release paper was then peeled off to produce synthetic leather for automobiles or furniture.

[Example 7]
The polyol compound (OH-2a, liquid temperature 25°C) from Production Example 3, calcium carbonate ( _CaCO3 ) as a filler, and a tertiary amine catalyst (SA1102, temperature-sensitive catalyst, manufactured by San-Apro Co., Ltd.) were mixed and stirred to form the base material as the OH component, and NCO-1 (25°C) from Production Example 5 was added as the curing agent (NCO component) and mixed and stirred with an instantaneous mixer. The mixture was then applied to automotive release paper with a surface coating at 250 g/ ^m2 with a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and post-dried for 6 minutes at 120°C. The release paper was then peeled off to produce synthetic leather for automobiles or furniture.

[Example 8]
As the OH component, the polyol compound of Production Example 4 (OH-2b, liquid temperature 25°C) and a tertiary amine catalyst (manufactured by San-Apro Co., Ltd.; SA1102, temperature-sensitive catalyst) were mixed and stirred to form the main component, and NCO-1 (25°C) of Production Example 5 was added as the curing agent (NCO component), and mixed and stirred with an instantaneous mixer. The mixture was then applied to the automotive skin-attached release paper at 400 g/ ^m2 with a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and dried for 5 minutes at 120°C. The release paper was then peeled off to produce synthetic leather for automobiles or furniture.

[Example 9]
The polyol compound (OH-2b, liquid temperature 25°C) from Production Example 4, calcium carbonate ( _CaCO3 ) as a filler, and a tertiary amine catalyst (SA1102, temperature-sensitive catalyst, manufactured by San-Apro Co., Ltd.) were mixed and stirred to form the base material as the OH component, and NCO-1 (25°C) from Production Example 5 was added as the curing agent (NCO component) and mixed and stirred with an instantaneous mixer. The mixture was then applied to automotive release paper with a skin at 250 g/ ^m2 with a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and dried for 5 minutes at 120°C. The release paper was then peeled off to produce synthetic leather for automobiles or furniture.

[Example 10]
The OH component was prepared by mixing and stirring the polyol compound of Production Example 3 (OH-2a, liquid temperature 25°C), calcium carbonate ( _CaCO3 ) as a filler, and a tertiary amine catalyst (San-Apro; SA1102, temperature-sensitive catalyst) to form the base material, and carbodiimide-modified liquid MDI (Mitsui Chemicals; Cosmonate LL, NCO 29.0%) was added as the curing agent (NCO component) and mixed and stirred with an instant mixer. The mixture was then applied to automotive surface release paper at 250 g/ ^m2 with a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and post-dried for 4 minutes at 120°C. The release paper was then peeled off to produce synthetic leather for automobiles or furniture.

[Comparative Example 2]
As the OH component, the above-mentioned (prepolymer: OH-R2, liquid temperature 50°C), tertiary amine catalyst (Air Products; 33LV) and tertiary amine catalyst (San-Apro; SA1102, temperature-sensitive catalyst) were mixed and stirred to form the main component, and NCO-1 (25°C) of Production Example 5 was added as the curing agent (NCO component), and the mixture was mixed and stirred with an instantaneous mixer, and applied to automotive surface release paper at 250 g/ ^m2 with a roll coater (Comma Coater: registered trademark).

This was pre-dried for 2 minutes at 120 minutes to leave it in a semi-cured state, and then a nonwoven fabric impregnated with a water-based polyurethane resin that had been separately prepared was placed on top of it and post-dried for 58 minutes at 120°C. The release paper was then peeled off to produce synthetic leather for automobiles or furniture.

As is clear from the polyol components in Table 1 and the test results shown in Table 3, Examples 6 to 10, which used polyols containing 2 to 3% by weight of autocatalytic amine polyol (Production Examples 3 and 4), hardened in 6 to 9 minutes at room temperature despite having a small amount of tertiary amine catalyst and a prepolymer component ratio of 35.0% or less, and the resin coating of the resulting synthetic leather had a peel strength of 1.7 kg/cm or more, which is sufficient for synthetic leather for automobiles or furniture, and also showed durability of more than 150,000 bending cycles at room temperature. For these reasons, Examples 6 to 10 were evaluated as two-component urethane resin compositions for synthetic leather that can be used to obtain high-quality synthetic leather for automobiles or furniture with excellent durability using environmentally friendly raw materials and production conditions.

The industrial application of this invention extends beyond sports shoes to general shoes, automobiles, furniture, bags, sacks, miscellaneous goods, clothing, industrial materials, and other synthetic leathers in general. By appropriately selecting and combining the polyols, chain extenders, and isocyanate compounds used in the production, this invention can be used to produce high-quality synthetic leather according to the purpose.

Claims (9)

A two-liquid urethane resin composition for synthetic leather, comprising a liquid base agent containing a polyol compound and a chain extender, and a liquid curing agent containing an isocyanate compound, the polyol compound being a liquid polyol compound containing 1 to 15% by mass of an autocatalytic amine-based polyol containing two or more tertiary amine groups and three or more hydroxyl groups per 100% by mass of the polyol compound. The two-liquid urethane resin composition for synthetic leather according to claim 1, wherein the amine-based polyol is an amine-based polyether polyol having a hydroxyl value of 300 to 1000 KOHmg/g, which is obtained by addition polymerization of propylene oxide (PO) or propylene oxide (PO) and ethylene oxide (EO) together with propylene oxide (PO). The two-component urethane resin composition for synthetic leather according to claim 1 or 2, wherein the base agent is a base agent containing a biopolyol or a biochain extender, or both of these. The two-component urethane resin composition for synthetic leather according to claim 1 or 2, wherein the equivalent ratio (isocyanate group/hydroxyl group) of the two-component urethane resin composition is 1.0 to 1.4. The two-component urethane resin composition for synthetic leather according to claim 3, wherein the equivalent ratio (isocyanate group/hydroxyl group) of the two-component urethane resin composition is 1.0 to 1.4. The two-component urethane resin composition for synthetic leather according to claim 1 or 2, wherein the prepolymer component ratio of the two-component urethane resin composition is less than 50%. The two-component urethane resin composition for synthetic leather according to claim 3, wherein the prepolymer component ratio of the two-component urethane resin composition is less than 50%. Synthetic leather having a base fabric surface coated with the two-liquid urethane resin composition for synthetic leather according to claim 1 or 2. Synthetic leather having a base fabric surface coated with the two-component urethane resin composition for synthetic leather described in claim 3.