WO2011145446A1

WO2011145446A1 - Polyurethane resin forming composition

Info

Publication number: WO2011145446A1
Application number: PCT/JP2011/060299
Authority: WO
Inventors: 裕章西村
Original assignee: 日本ポリウレタン工業株式会社
Priority date: 2010-05-20
Filing date: 2011-04-27
Publication date: 2011-11-24
Also published as: JP5482892B2; JPWO2011145446A1

Abstract

Disclosed is a polyurethane resin forming composition comprising a polyol (A), an isocyanate terminated prepolymer (B), a catalyst (C), and a reaction inhibitor (D), wherein: the polyol (A) is obtained by means of the transesterification of a polycarbonate polyol (a1), a polycaprolactone polyol (a2), and an aliphatic glycol (a3); the isocyanate terminated prepolymer (B) is obtained from the reaction between a poly(tetramethylene glycol) (b1) and an aliphatic organic diisocyanate (b2); the catalyst (C) is a dibutyl bis(2,4-pentanedionato) tin; the reaction inhibitor (D) is a 2,4-pentanedione; and the mass ratio of the catalyst in relation to the reaction inhibitor is 50 to 667 ((D)/(C)). The polyurethane resin forming composition has an excellent pot life and curing properties, and exhibits an excellent appearance, long-term stability, yellowing resistance, and wear resistance as a coating film.

Description

Polyurethane resin-forming composition

The present invention relates to a solventless polyurethane resin-forming composition formed on a substrate to be coated, for example.

The polyurethane resin field covers a wide range of fields such as electronic / electrical materials, automobile / railway vehicle materials, civil engineering / building materials, clothing materials, food materials, and medical materials.

Among the application fields of such polyurethane resins, for example, there are paints. Polyurethane resin paints are often used in the fields of architecture, civil engineering, vehicles, and clothing, and have excellent coating appearance, good coating film performance, and excellent durability.

Polyurethane resin paints are often used in combination with organic solvents from the viewpoints of workability, workability, and coating leveling. However, in recent years, the use of organic solvents has been scattered to the outside during the processing process and has become a cause of photochemical oxidants as volatile organic compounds (VOCs). VOC emissions have been restricted and regulatory measures have been taken. It has been.

Also, in order to maintain the performance of the polyurethane resin paint, for example, a two-component solution of a polyol and an organic polyisocyanate is achieved. However, it is difficult to achieve both the usable life (pot life) of coating or painting and the curability opposite to the usable time, and it is desired to balance this.

In addition, due to the absence of solvents in polyurethane resin paints, the leveling properties are reduced and air bubbles are mixed into the paint film, resulting in problems with the wear resistance and design of the paint film. Yes.

In addition, when used outdoors, the design may be deteriorated due to external enemy factors such as ultraviolet rays, moisture, heat, etc., and the improvement is desired.

In such a background, in order to solve these problems, for example, Patent Document 1 discusses the use of a solvent-free resin by using a water-based resin.

For example, in Patent Documents 2 and 3, as a method of achieving both pot life and curability, a polyurethane polyol obtained by reacting a polyol having a side chain with an organic diisocyanate, an organic solvent, an organic tin compound, and acetylacetone A configured urethane resin composition has been proposed.

Moreover, as a technique for achieving both pot life and curability, for example, in Patent Document 4, a urethane coating composition for repairing automobiles contains tin or zirconium and a metal compound other than these and an excess chelating agent. It has been proposed to use reaction control agents.

Furthermore, as a technique for achieving both pot life and curability, for example, Patent Document 5 proposes a catalyst system in which a weight ratio of metal acetylacetonate to acetylacetone is 2: 1 in a polyurethane foam production method. .

As a method for achieving both pot life and curability of a solvent-free polyurethane resin film material, for example, Patent Document 6 proposes a system that uses an organometallic catalyst for curing reaction in a fine powder form at room temperature and a curing reaction inhibitor. Has been.

For example, Patent Document 7 proposes a system using dibutyltin dilaurate in combination with acetylacetone as a cast molded film composition and a film using the composition.

JP 2008-303250 A JP-A-6-1000085 JP 2000-167085 A JP 2002-173639 A JP 2008-285681 A JP 2010-215679 A International Publication No. 08/026751 Pamphlet

Since the polyurethane resin-forming composition formed on the substrate is a solvent-free two-component system, sufficient pot life and curability in a shorter time are obtained from the viewpoint of workability and workability. Desired. In addition, since it is frequently used in the fields of architecture, civil engineering, vehicles and clothing, the polyurethane resin-forming composition is required to have design properties such as yellowing resistance and high appearance on the formed coating film.

However, in the conventional polyurethane resin-forming composition, it is difficult to achieve both pot life and curability, and when trying to achieve both, the formed coating film is yellowed, or has characteristics such as wear and durability. Tend to decrease.

The present invention has been made based on the above circumstances. The present invention provides a solvent-free polyurethane that is formed on a substrate that has both pot life and curability and is excellent in design properties such as wear resistance, stability over time, yellowing resistance of coating film, and appearance. An object is to provide a resin-forming composition.

The present invention is a polyurethane resin-forming composition comprising a polyol (A), an isocyanate group-terminated prepolymer (B), a catalyst (C), and a reaction inhibitor (D), wherein the polyol (A) , Polycarbonate polyol (a1), polycaprolactone polyol (a2) and aliphatic glycol (a3) are obtained by transesterification reaction, and the isocyanate group-terminated prepolymer (B) contains polytetramethylene glycol (b1) and fat. Obtained by a reaction with an aromatic organic diisocyanate (b2), the catalyst (C) is dibutylbis (2,4-pentanedionato) tin, and the reaction inhibitor (D) is 2,4-pentanedione. A polyurethane resin-forming property, wherein the mass ratio (D) / (C) of the reaction inhibitor to the catalyst is 50 to 667 To provide a Narubutsu.

In the polyurethane resin-forming composition, it is preferable that the polyol (A) and the isocyanate group-terminated prepolymer (B) are liquid at room temperature.

According to the present invention, a solvent-free type that is formed on a substrate that has both pot life and curability and is excellent in design properties such as abrasion resistance, temporal stability, yellowing resistance, and appearance of a coating film. The polyurethane resin-forming composition can be provided.

A preferred embodiment of the present invention will be described below.

The polyurethane resin-forming composition of the present invention contains a polyol (A), an isocyanate group-terminated prepolymer (B), a catalyst (C), and a reaction inhibitor (D). The polyurethane resin-forming composition according to this embodiment comprises a polyol (A) obtained by transesterification of a polycarbonate polyol (a1), a polycaprolactone polyol (a2) and an aliphatic glycol (a3), and a polytetramethylene glycol ( It is obtained by blending an isocyanate group-terminated prepolymer (B) obtained by reaction of b1) and an aliphatic organic diisocyanate (b2), a catalyst (C), and a reaction inhibitor (D).

<(A) polyol>
The polyol (A) is obtained by a transesterification reaction between the polycarbonate polyol (a1), the polycaprolactone polyol (a2) and the aliphatic glycol (a3).

The ratio [(a1) + (a3)] / (a2)] of the polycarbonate polyol (a1) and the aliphatic glycol (a3) to the polycaprolactone polyol (a2) is preferably 65/35 or more. Further, there is no particular upper limit for the mass ratio [(a1) + (a3)] / (a3), and (a1) may be nearly 100% by mass. Since it is preferable to handle the polyol (A) as a liquid at room temperature, the total amount of (a1) and (a3) is preferably 75% by mass (mass ratio 75/25) or less.

<Method for producing polyol (A)>
First, a polycarbonate polyol (a1), a polycaprolactone polyol (a2) and an aliphatic glycol (a3) are blended and dissolved at 60 ° C. until uniform while bubbling nitrogen gas. Thereafter, the ester exchange reaction is performed at 190 ° C. until the target hydroxyl value is reached.

<(A1) Polycarbonate polyol>
The polycarbonate polyol (a1), which is one of the raw materials of the polyol, is not particularly limited in type, for example, a dehydrochlorination reaction of a short chain polyol and phosgene, or a short chain polyol, a dialkyl carbonate, an alkylene carbonate, It is suitably obtained by a transesterification condensation reaction with a low molecular carbonate such as diaryl carbonate.

Examples of the short-chain polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5- Pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, dimethylolheptane, Polyols having a molecular weight of less than 500 such as diethylene glycol, dipropylene glycol, neopentyl glycol, diethylene glycol, dipropylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, glycerin, trimethylolpropane Can be mentioned. A polyol can be used individually or in mixture of 2 or more types.

Examples of the dialkyl carbonate include dimethyl carbonate and diethyl carbonate. Examples of the alkylene carbonate include ethylene carbonate and propylene carbonate. These can be used individually or in mixture of 2 or more types.

From the viewpoint of further increasing the mechanical strength of the resulting polyurethane resin film, a polycarbonate polyol using a linear aliphatic glycol (a3) that contributes to the mechanical strength through the development of crystallinity is preferable, and 1,6-hexanediol is particularly preferable. It is preferable that it is a thing obtained by reaction with dialkyl carbonate. Similarly, from the viewpoint of mechanical strength and workability, the number average molecular weight of the polycarbonate polyol is preferably 500 to 5000, and more preferably 1000 to 3000.

<(A2) Polycaprolactone polyol>
Examples of the polycaprolactone polyol (a2) include those obtained by ring-opening addition of either or both of ε-caprolactone and alkyl-substituted ε-caprolactone using the short-chain polyol used in the above polycarbonate as an initiator. Can be used. Further, from the viewpoint of mechanical strength and workability, the number average molecular weight of the polycaprolactone polyol is preferably 500 to 5,000, more preferably 500 to 2,000.

<(A3) Aliphatic glycol>
Examples of the aliphatic glycol (a3) include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, , 5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, di- Mention may be made of methylol heptane, diethylene glycol, dipropylene glycol and neopentyl glycol. The aliphatic glycol (a3) preferably has a molecular weight of 200 or less, and particularly preferably 1,6-hexanediol, from the viewpoint of further increasing the mechanical strength of the resulting polyurethane resin film.

<(B) Isocyanate group-terminated prepolymer>
The isocyanate group-terminated prepolymer (B) is obtained by a reaction between polytetramethylene glycol (b1) and an aliphatic organic diisocyanate (b2).

The isocyanate group-terminated prepolymer (B) preferably has an isocyanate group content of 4 to 12% by mass and an unreacted organic diisocyanate content of 1% by mass or less. When the isocyanate group content is less than 4%, the amount mixed with the polyol increases, and the mechanical strength of the polyurethane resin film may be lowered. In addition, when the isocyanate group content exceeds 12%, the storage stability may be reduced due to the reaction with moisture, or lumps and aggregates may be generated due to poor mixing with the polyol. Furthermore, if the content of unreacted organic diisocyanate exceeds 1% by mass, odor problems and storage stability may be deteriorated.

<Method for producing isocyanate group-terminated prepolymer>
First, polytetramethylene glycol (b1) and aliphatic organic diisocyanate (b2) are blended, and a urethanization reaction is performed at 80 ° C. to the desired isocyanate group content while bubbling nitrogen gas. Thereafter, thin film distillation is performed at 140 ° C. and 0.3 Torr until the content of unreacted organic diisocyanate is 1% by mass or less.

<(B1) Polytetramethylene glycol>
The molecular weight of polytetramethylene glycol (b1) is not particularly limited, but the number average molecular weight is preferably 250 to 1000, and preferably 500 to 800 from the viewpoint of the appearance and handling properties of the resulting polyurethane resin film. Is more preferable.

<(B2) Aliphatic organic diisocyanate>
As the aliphatic organic diisocyanate (b2), linear or branched aliphatic diisocyanates and alicyclic diisocyanates are preferable from the viewpoint of compatibility between pot life and curability and yellowing resistance.

Examples of linear or branched aliphatic diisocyanates include hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methyl-pentane-1,5-diisocyanate, 3-methyl-pentane-1,5-diisocyanate, lysine diisocyanate and And trioxyethylene diisocyanate. Examples of the alicyclic diisocyanate include isophorone diisocyanate, cyclohexyl diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated tetramethylxylene diisocyanate. These aliphatic organic diisocyanates can be used alone or in combination of two or more. In addition, adduct-modified products, burette-modified products, uretdione-modified products, uretoimine-modified products, isocyanurate-modified products, and carbodiimide-modified products of the above aliphatic organic diisocyanates can also be used. In the present embodiment, linear aliphatic diisocyanate is preferable from the viewpoint of ease of blending with polyol at the time of polyurethane film production, appearance of the resulting polyurethane resin film, and mechanical strength, and hexamethylene diisocyanate is most preferable. preferable.

Either one or both of the polyol and the isocyanate group-terminated prepolymer may be solid at room temperature. From the viewpoint of excellent handling properties when storing or transporting the polyol and the isocyanate group-terminated prepolymer, or when the polyol and the isocyanate group-terminated prepolymer are mixed and subjected to a curing reaction in order to form a film, no heat-melting treatment is required. From the viewpoint, it is preferable that both the polyol and the isocyanate group-terminated prepolymer are liquid at room temperature.

The blending ratio of the polyol and the isocyanate group-terminated prepolymer in forming the film is not particularly limited, but the molar ratio of the isocyanate group in the isocyanate group-terminated prepolymer and the hydroxyl group in the polyol (isocyanate group / (Hydroxyl group) is preferably blended so as to be 0.90 to 1.30. When outside this range, performance such as wear resistance may be deteriorated.

The polyurethane resin-forming composition according to this embodiment can be used by separately managing a polyol and an isocyanate group-terminated prepolymer and blending it together with a curing catalyst during film formation. Thereby, it is excellent in the storage stability when storing for a long time before using a polyol and an isocyanate group terminal prepolymer.

<(C) Catalyst>
Dibutylbis (2,4-pentanedionato) tin used as the catalyst (C) serves as an accelerator in curing the polyurethane resin-forming composition and is indispensable.

The amount of the catalyst to be added is not particularly limited, but from the viewpoint of processing time, it is preferably blended in the range of 300 ppm to 4000 ppm based on the total amount of polyol (A) and isocyanate group-terminated prepolymer. When the addition amount is less than 300 ppm, the resin is uncured and may deteriorate in appearance and wear resistance. Moreover, when the addition amount exceeds 4000 ppm, the pot life may not be satisfied.

<(D) Reaction inhibitor>
The 2,4-pentanedione used as the reaction inhibitor (D) is useful for making the pot life and coating film appearance of the polyurethane resin-forming composition set formed on the substrate of the present invention practical. It is indispensable.

The addition amount of the reaction inhibitor is preferably 1.5 to 20% by mass based on the total amount of the polyol (A) and the isocyanate group-terminated prepolymer. When the addition amount of the reaction inhibitor is less than 1.5% by mass, it may be difficult to satisfy the pot life. When the addition amount exceeds 20% by mass, repelling occurs when the resin film is formed, and the appearance is May be worse.

The mass ratio (D) / (C) of the reaction inhibitor to the catalyst is preferably 50 to 667. When the ratio of the reaction inhibitor to 1 part by mass of the catalyst is less than 50 parts by mass, it becomes difficult to satisfy a practical pot life, and when it exceeds 667 parts by mass, repelling occurs when forming the resin film, Appearance may deteriorate.

In the case of a curing system in which a catalyst such as general dibutyltin dilaurate and a retarder are used in combination, the curing reaction proceeds as the temperature increases, so that a resin film is formed with air bubbles mixed inside. On the other hand, the polyurethane resin-forming composition according to this embodiment exhibits the activity of the catalyst for the first time when the reaction inhibitor 2,4-pentanedione coordinated to the catalyst is vaporized at 140 ° C. For this reason, when the catalyst is lower than the vaporization temperature, the viscosity of the resin decreases, and at this time, bubbles present in the resin film are removed. Thereafter, 2,4-pentanedione is vaporized and the urethanization reaction proceeds rapidly, so that a resin film with high smoothness and excellent design can be formed.

The polyurethane resin-forming composition includes, as necessary, an antioxidant, an ultraviolet absorber, a pigment, a dye, a flame retardant, a hydrolysis inhibitor, a lubricant, a plasticizer, a filler, an antistatic agent, and a dispersant. In addition, additives such as storage stabilizers can be appropriately blended.

Since the polyurethane resin-forming composition according to the present embodiment is not aqueous, it can reduce the generation of aggregates and sedimentation over time, and can reduce energy and time for drying the film, Both pot life and curability can be achieved. Moreover, since the aliphatic isocyanate is used, the formed coating film is excellent in yellowing resistance. Furthermore, since the polyol is obtained from the polycarbonate polyol, the wear resistance and durability of the formed coating film can be sufficiently improved. In addition, by using a specific catalyst, the formation and sedimentation of catalyst aggregates over time can be reduced, and discoloration, swelling and foaming of the coating film can be sufficiently suppressed, so that a coating film having a good appearance can be formed. .

That is, according to the present invention, a solvent-free polyurethane resin-forming composition that has both pot life and curability and is excellent in design properties such as wear resistance, stability over time, yellowing resistance of coating film and appearance. Is obtained.

The polyurethane resin-forming composition according to this embodiment can be used for forming a polyurethane resin film on a substrate, and for example, can form a paint film on a substrate to be coated as a paint.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Example 1>
(1) Preparation of polyol 44 g of 1,6-hexanediol, 1,6-hexanediol and diethyl carbonate were added to a 2-liter four-necked flask equipped with a stirrer, thermometer, cooling pipe and oxygen gas introduction pipe. Is charged with 656 g of a polycarbonate diol having a number average molecular weight of 2000 obtained by deethanol reaction of 1, and 300 g of a bifunctional polycaprolactone diol having a number average molecular weight of 1000 obtained by ring-opening addition reaction of ε-caprolactone with 1,4-butanediol. These were stirred and nitrogen gas was bubbled and subjected to transesterification at 190 ° C. for 24 hours to obtain a normal temperature liquid polyol (1). When the hydroxyl group content of the polyol (1) was measured by a method according to JIS K1557, it was 112 mgKOH /, and the number average molecular weight was 1000.

(2) Preparation of isocyanate group-terminated prepolymer Hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., NCO content: 49) was added to a 2-liter four-necked flask equipped with a stirrer, thermometer, cooling tube and oxygen gas introduction tube. (9 mass%, hereinafter referred to as “HDI”) was charged with 700 g of polytetramethylene glycol having a number average molecular weight of 650, and nitrogen gas was bubbled while stirring, followed by urethanization reaction at 80 ° C. for 4 hours. Thereafter, thin film distillation was performed under conditions of 140 ° C. and 0.3 Torr, and unreacted HDI was removed to obtain an isocyanate group-terminated prepolymer. The obtained isocyanate group-terminated prepolymer had an NCO content of 8% by mass. Moreover, when it measured by GPC (gel permeation chromatography), unreacted HDI was 0.1 mass%. The GPC measurement conditions are as follows.

-Measuring instrument: "HLC-8120" (manufactured by Tosoh Corporation)
Column: “TSKguardcolumn HXL-L” (manufactured by Tosoh Corporation), particle size 6 μm, size 6 mm ID × 30 cm × 4, carrier: tetrahydrofuran (THF)
・ Detector: parallax refraction ・ Sample: 0.1 mass% THF solution ・ Calibration curve: polystyrene

(3) Preparation of polyurethane resin-forming composition (polyol / isocyanate group-terminated prepolymer mixed solution) 100 g of polyol (1), dibutylbis (2,4-pentanedionato) tin (hereinafter referred to as “catalyst (1)”) 0.06 g and 2,4-pentanedione (hereinafter referred to as “reaction inhibitor (1)”) 3.1 g were added, and the mixture was stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes. Thereafter, 105 g of the isocyanate group-terminated prepolymer was blended, and further stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes to prepare a polyol / isocyanate group-terminated prepolymer mixed solution.

<Example 2>
100 g of the polyol (1) obtained in Example 1, 0.11 g of the catalyst (1) and 43.2 g of the reaction inhibitor (1) were added, and the mixture was stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes. Thereafter, 116 g of the isocyanate group-terminated prepolymer obtained in Example 1 was blended, and further stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes to prepare a polyol / isocyanate group-terminated prepolymer mixed solution.

<Example 3>
100 g of the polyol (1) obtained in Example 1, 0.07 g of the catalyst (1) and 46.7 g of the reaction inhibitor (1) were added, and the mixture was stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes. Thereafter, 137 g of the isocyanate group-terminated prepolymer obtained in Example 1 was blended, and further stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes to prepare a polyol / isocyanate group-terminated prepolymer mixed solution.

<Example 4>
100 g of the polyol (1) obtained in Example 1, 0.86 g of the catalyst (1) and 43.2 g of the reaction inhibitor (1) were added, and the mixture was stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes. Thereafter, 116 g of the isocyanate group-terminated prepolymer obtained in Example 1 was blended, and further stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes to prepare a polyol / isocyanate group-terminated prepolymer mixed solution.

<Comparative Example 1>
100 g of the polyol (1) obtained in Example 1 and 0.11 g of the catalyst (1) were added, and the mixture was stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes. Thereafter, 116 g of the isocyanate group-terminated prepolymer obtained in Example 1 was blended, and further stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes to prepare a polyol / isocyanate group-terminated prepolymer mixed solution.

<Comparative Example 2>
100 g of the polyol (1) obtained in Example 1, 0.06 g of the catalyst (1) and 1.2 g of the reaction inhibitor (1) were added, and the mixture was stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes. Thereafter, 105 g of the isocyanate group-terminated prepolymer obtained in Example 1 was blended, and further stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes to prepare a polyol / isocyanate group-terminated prepolymer mixed solution.

<Comparative Example 3>
100 g of the polyol (1) obtained in Example 1, 0.06 g of the catalyst (1) and 48 g of the reaction inhibitor (1) were added, and the mixture was stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes. Thereafter, 105 g of the isocyanate group-terminated prepolymer obtained in Example 1 was blended, and further stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes to prepare a polyol / isocyanate group-terminated prepolymer mixed solution.

<Comparative Example 4>
100 g of the polyol (1) obtained in Example 1, 0.06 g of dioctyltin dilaurate (hereinafter referred to as “catalyst (2)”), and 3.1 g of the reaction inhibitor (1) were added. Stirring was performed at a stirring speed of 300 rpm for 3 minutes. Thereafter, 105 g of the isocyanate group-terminated prepolymer obtained in Example 1 was blended, and further stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes to prepare a polyol / isocyanate group-terminated prepolymer mixed solution.

<Comparative Example 5>
100 g of polyol (2) having a number average molecular weight of 1000 obtained by reacting 1,6-hexanediol and isophthalic acid, bis (2,4-pentanedionato) nickel (hereinafter referred to as “catalyst (3)”) 0.06 g and 3.1 g of the reaction inhibitor (1) were added, and the mixture was stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes. Thereafter, 105 g of the isocyanate group-terminated prepolymer obtained in Example 1 was blended, and further stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes to prepare a polyol / isocyanate group-terminated prepolymer mixed solution.

<Comparative Example 6>
100 g of polyol (1) obtained in Example 1 and di-n-octyltin maleate polymer [trade name: KS-1010A-1, manufactured by Kyodo Pharmaceutical Co., Ltd., hereinafter referred to as catalyst (4)] .22 g, a mixture of mono (2-ethylhexyl acid phosphate) and bis (2-ethylhexyl acid phosphate) (trade name: JP-508, manufactured by Johoku Chemical Co., Ltd., hereinafter referred to as “reaction inhibitor (2)”) 0.07g was added and it stirred for 3 minutes with the stirring speed of 300 rpm with the three one motor. Thereafter, 116 g of the isocyanate group-terminated prepolymer obtained in Example 1 was blended, and further stirred with a three-one motor at a stirring speed of 300 rpm for 3 minutes to prepare a polyol / isocyanate group-terminated prepolymer mixed solution.

Table 1 below summarizes the blending ratio (unit: “g”) of the polyurethane resin-forming compositions (polyol / isocyanate group-terminated prepolymer mixed solution) prepared in Examples 1 to 4 and Comparative Examples 1 to 6. Show.

[Evaluation of polyurethane resin-forming composition]
The polyol / isocyanate group-terminated prepolymer mixed solutions obtained in Examples 1 to 4 and Comparative Examples 1 to 6 were used, and the following items were evaluated.

(1) Pot life About 13 g of the polyol / isocyanate-terminated prepolymer mixed solution was collected in an aluminum sample pan, and the viscosity was 10000 mPa · s at 45 ° C. and 5 rpm using a Brookfield viscometer (manufactured by Brookfield). The time to become was measured. Pot life was evaluated based on the following evaluation criteria.

(Evaluation criteria)
・ 120 minutes or more: Pass (Evaluation: A)
・ 60 minutes or more and less than 120 minutes: Pass (a level where there is no practical problem, evaluation: B)
-Less than 60 minutes: Fail (Evaluation: C)

(2) Curability The polyol / isocyanate group-terminated prepolymer mixed solution was poured onto release paper, applied to a thickness of 50 μm with a bar coater, cured at 140 ° C., and the time for tack-free was measured. The curability was evaluated based on the following evaluation criteria.

(Evaluation criteria)
-Less than 3 minutes: Pass (Evaluation: A)
・ 3 minutes or more to less than 10 minutes: Passed (practical problem level, evaluation: B)
・ 10 minutes or more: Fail (Evaluation: C)

(3) Smoothness (average surface roughness)
The polyol / isocyanate group-terminated prepolymer mixed solution was poured onto release paper, applied to a thickness of 50 μm with a bar coater, and cured at 140 ° C. using a laser microscope LEXT OLS4000 (manufactured by Olympus). The line average roughness (Ra) was measured. The smoothness was evaluated based on the following evaluation criteria.

(Evaluation criteria)
・ Less than 1 μm: Pass (Evaluation: A)
・ 1 μm or more and less than 3 μm: Pass (Level of practical problems, evaluation: B)
・ 3 μm or more: Fail (Evaluation: C)

(4) Preparation of non-woven fabric / polyurethane film sheet A polyol / isocyanate group-terminated prepolymer mixed solution is poured onto release paper, applied to a thickness of 50 μm with a bar coater, cured at 140 ° C. for 10 minutes, and first polyurethane A film layer was obtained. A mixed solution is poured onto the first polyurethane film layer, a second polyurethane film layer is applied to a thickness of 100 μm with a bar coater, and a nylon nonwoven fabric having a thickness of 2 mm is further applied to the second polyurethane film layer. Combined and cured at 140 ° C. for 10 minutes to prepare a nonwoven fabric / polyurethane film sheet. This nonwoven fabric / polyurethane film sheet was used for the following evaluation.

(5) Abrasion resistance:
Using a Taber abrasion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the abrasion amount of the polyurethane film on the non-woven fabric / polyurethane film sheet was measured under the conditions of a load of 1 kg, a disk rotation speed of 500 rpm and a wear wheel H-22. .

(6) Yellowing resistance:
Using a super xenon weather meter SX75 (manufactured by Suga Test Instruments Co., Ltd.), the presence or absence of yellowing of the polyurethane film in the nonwoven fabric / polyurethane film sheet after 168 hours of irradiance of 160 W / m ² was confirmed.

(7) Storage stability test:
A solution in which a polyol, a catalyst, and a reaction inhibitor were mixed was allowed to stand at 50 ° C. for 168 hours, and the presence or absence of precipitates, pot life, and curability were evaluated.
The above results are shown in Table 2 below.

As shown in Table 2 above, the polyurethane resin-forming compositions of Examples 1 to 4 have both pot life and curability, and are excellent in abrasion resistance, aging stability, yellowing resistance and appearance of the coating film. Are better.

In contrast, Comparative Example 1 and Comparative Example 2 are inferior in pot life and curability. Moreover, in the comparative example 3, the repellency of a urethane film is remarkable and it is inferior to smoothness. Comparative Example 4 and Comparative Example 5 are inferior in compatibility between pot life and curability, yellowing resistance and appearance. In Comparative Example 6, the pot life was significantly decreased in the test after storage stability, and the performance was not satisfied.

Claims

A polyurethane resin-forming composition comprising a polyol (A), an isocyanate group-terminated prepolymer (B), a catalyst (C), and a reaction inhibitor (D),
The polyol (A) is obtained by a transesterification reaction of a polycarbonate polyol (a1), a polycaprolactone polyol (a2) and an aliphatic glycol (a3).
The isocyanate group-terminated prepolymer (B) is obtained by reaction of polytetramethylene glycol (b1) and aliphatic organic diisocyanate (b2),
The catalyst (C) is dibutylbis (2,4-pentanedionato) tin, the reaction inhibitor (D) is 2,4-pentanedione, and the mass ratio of the reaction inhibitor to the catalyst ( A polyurethane resin-forming composition, wherein D) / (C) is 50 to 667.
The polyurethane resin-forming composition according to claim 1, wherein the polyol (A) and the isocyanate group-terminated prepolymer (B) are liquid at room temperature.