POLYISOCYANATE COMPOSITION, COATING MATERIAL COMPOSITION AND COATING FILM

Abstract

A polyisocyanate composition includes a polyisocyanate having an isocyanurate group, derived from one or more types of diisocyanates selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, UV absorption peaks of a trimeric equivalent of the diisocyanate and a tetrameric equivalent of the diisocyanate being present in a spectrum of the polyisocyanate composition measured by gel permeation chromatography, the ratio ((B)/(A)) of the height (B) of the UV absorption peak of the tetrameric equivalent of the diisocyanate to the height (A) of the UV absorption peak of the trimeric equivalent of the diisocyanate being 0.01 to 3, and the content of a volatile component produced from storage for three months at 60 C. being 0.3% by mass or less with respect to the total mass of the polyisocyanate composition prior to storage, the volatile component having been removed from the polyisocyanate composition in advance.

Claims

1. A polyisocyanate composition, comprising a polyisocyanate having an isocyanurate group derived from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, the polyisocyanate composition having UV absorption peaks of a trimeric equivalent of the diisocyanate and a tetrameric equivalent of the diisocyanate in a spectrum of the polyisocyanate composition measured by gel permeation chromatography, wherein a ratio (B)/(A) of a height (B) of the UV absorption peak of the tetrameric equivalent of the diisocyanate to a height (A) of the UV absorption peak of the trimeric equivalent of the diisocyanate is 0.01 to 3, and a content of a volatile component produced by storage for three months at 60 C., relative to a total mass of the polyisocyanate composition prior to the storage, from which the volatile component is removed in advance, is 0.3% by mass or less.

2. The polyisocyanate composition according to claim 1, further comprising a polyisocyanate having an allophanate group.

3. The polyisocyanate composition according to claim 1, further comprising a polyisocyanate having a uretdione group.

4. The polyisocyanate composition according to claim 1, further comprising a polyisocyanate having an iminooxadiazinedione group.

5. A coating material composition comprising a polyisocyanate composition of claim 1.

6. A coating film formed by a coating material composition of claim 5.

7. The polyisocyanate composition according to claim 2, further comprising a polyisocyanate having a uretdione group.

8. The polyisocyanate composition according to claim 2, further comprising a polyisocyanate having an iminooxadiazinedione group.

9. The polyisocyanate composition according to claim 3, further comprising a polyisocyanate having an iminooxadiazinedione group.

10. The polyisocyanate composition according to claim 7, further comprising a polyisocyanate having an iminooxadiazinedione group.

11. A coating material composition comprising a polyisocyanate composition of claim 2.

12. A coating material composition comprising a polyisocyanate composition of claim 3.

13. A coating material composition comprising a polyisocyanate composition of claim 4.

14. A coating material composition comprising a polyisocyanate composition of claim 7.

15. A coating material composition comprising a polyisocyanate composition of claim 8.

16. A coating material composition comprising a polyisocyanate composition of claim 9.

17. A coating material composition comprising a polyisocyanate composition of claim 10.

18. A coating film formed by a coating material composition of claim 14.

19. A coating material composition comprising a polyisocyanate composition of claim 15.

20. A coating film formed by a coating material composition of claim 17.

Description

EXAMPLES

[0253] Hereinafter, the present invention will be described in further detail on the basis of Examples. However, the present invention is not limited to these Examples. The measurement method and evaluation method of physical properties of polyisocyanate compositions obtained in Examples and Comparative Examples will be described below.

[Physical Property 1] Isocyanate Group Concentration (NCO %)

[0254] The concentration of isocyanate group of polyisocyanate (NCO %) was defined as the amount (% by mass) of isocyanate group contained in the polyisocyanate, and measured by the following method.

[0255] 5 to 10 g of polyisocyanate was accurately weighed and then dissolved in 20 mL of toluene. 20 mL of a toluene solution of 2N n-dibutylamine was added to the resultant solution, and then the mixture was left still at room temperature for 15 minutes to allow the reaction to proceed. After the reaction ended, the total amount of the resultant reaction mixture was subjected to back-titration with 1N hydrochloric acid using an APB-410 type automatic titrator manufactured by KYOTO ELECTRONICS MANUFACTURING CO., LTD., to measure the volume (sample titration volume) of 1N hydrochloric acid required to neutralize unreacted n-dibutylamine in the reaction mixture was determined. On the other hand, the same procedure as described above was conducted except that polyisocyanate was not used, and the volume (blank titration volume) of 1N hydrochloric acid required to neutralize unreacted n-dibutylamine was also measured. The isocyanate group concentration (% by mass) was calculated by the following formula (i) using the measured sample titration volume and blank titration volume.

Isocyanate group concentration (% by mass)=[{blank titration volume (mL)sample titration volume (mL)}42/{sample mass (g)1000}]100(i)

[Physical Property 2] Viscosity

[0256] The viscosity was measured at 25 C. using an E-type viscometer manufactured by Tokimec, Inc.). The measurement was conducted using a standard rotor (1 34R24). The rotation speed was set as described below.

[0257] 100 r.p.m. (in the case where the viscosity was less than 128 mPa.Math.s.)

[0258] 50 r.p.m. (in the case where the viscosity was 128 mPa.Math.s or more and less than 256 mPa.Math.s.)

[0259] 20 r.p.m. (in the case where the viscosity was 256 mPa.Math.s or more and less than 640 mPa.Math.s.)

[0260] 10 r.p.m. (in the case where the viscosity was 640 mPa.Math.s or more and less than 1280 mPa.Math.s.)

[0261] 5 r.p.m. (in the case where the viscosity was 1280 mPa.Math.s or more and less than 2560 mPa.Math.s.)

[0262] The viscosity was measured after confirming that the amount of 1,6-hexamethylene diisocyanate (HDI) was less than 0.5% by mass from measurement results of the HDI amount described in [physical property 3] shown below

[Physical Property 3] Measurement of the Amount of 1,6-Hexamethylene Diisocyanate (HDI)

[0263] The peak area having a retention time corresponding to the molecular weight of HDI was determined under below-mentioned measurement conditions of gel permeation chromatography (GPC). The percentage of the peak area, relative to the total peak area in the chromatogram, was determined as the HDI amount (% by mass).

(Measurement Conditions)

[0264] Carrier: THF [0265] Flow rate: 0.6 mL/min [0266] Column: Column series TSKgel Super H1000, TSKgel Super H2000, and TSKgel Super H3000 (all of which were manufactured by TOSOH CORPORATION) were connected with each other. [0267] Detector: Refractometer [0268] GPC apparatus: HLC-8120 GPC (manufactured by TOSOH CORPORATION)

[Physical Property 4] Ratio ((B)/(A)) of the Height (B) of the UV Absorption Peak of the Tetrameric Equivalent of the Diisocyanate to the Height (A) of the UV Absorption Peak of the Trimeric Equivalent of the Diisocyanate

[0269] Each polyisocyanate composition was subjected to GPC under measurement conditions mentioned below. Then, the height (B) of the UV absorption peak at the retention time corresponding to the molecular weight of diisocyanate tetramer was determined based on the height (A) of the UV absorption peak at a retention time corresponding to the molecular weight of diisocyanate trimer (isocyanurate trimer) (around 11.7 minutes), the height (A) being read as 100. The ratio ((B)/(A)) of the resultant height (B) relative to the height (A) was calculated. The retention time corresponding to the molecular weight of the diisocyanate tetramer was measured at a peak between the UV absorption peak of the diisocyanate trimer (at around 11.7 minutes) and the UV absorption peak of the diisocyanate pentamer (at around 11.0 minutes).

(Measurement Conditions)

[0270] Carrier: THF [0271] Column: Column series TSKgel Super H1000, TSKgel Super H2000, and TSKgel Super H3000 (all of which were manufactured by TOSOH CORPORATION) were connected with each other. [0272] Detector: UV (used when the height ratio was calculated; measurement wavelength: 254 nm) [0273] Refractometer (used when the diisocyanate trimer and pentamer were identified.) [0274] GPC apparatus: HLC-8120 GPC (manufactured by TOSOH CORPORATION)

[Physical Property 5] Identification of Isocyanurate Group

[0275] CDCl.sub.3 solutions of each polyisocyanate composition obtained in Examples and Comparative Examples were prepared. Then, the resultant solutions were subjected to .sup.13C-NMR measurement under the following measurement conditions to identify an isocyanurate group.

(Measurement Conditions)

[0276] Measurement apparatus: Burker Biospin Avance 600 [0277] Observed nuclei: .sup.13C (150 MHz) [0278] Solvent: CDCl.sub.3 [0279] Cumulated number: 10,000 [0280] Chemical shift standard: CDCl.sub.3 (77 ppm) [0281] Characteristic peak (chemical shift value) of each composition Isocyanurate group: strong peak at around 148.5 ppm

[Physical Property 6] Volatile Component Generated by Storage at 60 C. for 3 Months

[0282] 50 g of each polyisocyanate composition obtained in Examples and Comparative Examples was weighed into eggplant flasks, and then subjected to decompression treatment at 23 C. and 0.1 Torr for 1 hour.

[0283] After the decompression treatment was ended, the reduced pressure in the eggplant flasks was brought into the normal pressure with dry nitrogen, followed by putting stoppers on the eggplant flasks filled with dry nitrogen to determine the mass (C) thereof at the time. The resultant samples filled with nitrogen were stored in an oven at 60 C. for 3 months. After the storage, the resultant samples were immersed in an oil bath at 100 C., and then subjected to heating decompression treatment at 0.1 Torr for 1 hour. After the heating decompression treatment was ended, the reduced pressure in the eggplant flasks was brought into the normal pressure with dry nitrogen, and then the resultant samples were cooled at 23 C., followed by putting stoppers on the eggplant flasks filled with dry nitrogen to determine the mass (D) thereof at the time.

[0284] The ratio of volatile components was determined by the following formula.

Mass reduction rate (% by mass)=[(C)(D)]/(C)100

[Evaluation 1] Color Stability (Confirmation of Yellowing Degree when Stored Under High-Temperature Conditions)

[0285] Each polyisocyanate composition was put in 50 mL well-dried glass bottles and then the glass bottles were filled with nitrogen. Then, the glass bottles were stored in an oven at 60 C. for 3 months. The Hazen color numbers (APHA) of the polyisocyanate compositions before and after storage were measured using Lovibond automatic chromatometer PFXi-195. Then, the color stability (the yellowing degree when stored under high-temperature conditions) was evaluated in accordance with the following evaluation criteria.

(Evaluation Criteria)

[0286] : APHA was less than 20.

[0287] : APHA was 20 or more and less than 50.

[0288] x: APHA was 50 or more.

[Evaluation 2] Viscosity Stability (Confirmation of the Viscosity Increase Ratio when Stored Under High-Temperature Conditions)

[0289] Each polyisocyanate composition was put in 50 mL well-dried glass bottles and then the glass bottles were filled with nitrogen. Then, the glass bottles were stored in an oven at 60 C. for 3 months. The viscosity of the polyisocyanate compositions before and after storage was measured by the method described in the above-mentioned [Physical property 2]. Then, the viscosity increase ratio (%) was calculated by the following formula (ii).

Viscosity increase ratio (%)=(viscosity after storage)/(viscosity before storage)100(ii)

[0290] Then, the viscosity stability (the viscosity increase ratio when stored under high-temperature conditions) was evaluated in accordance with the following evaluation criteria.

(Evaluation Criteria)

[0291] : The viscosity increase ratio was less than 5%.

[0292] : The viscosity increase ratio was 5% or more and less than 10%.

[0293] x: The viscosity increase ratio was 10% or more.

[Evaluation 3] Drying Property of Coating Material Composition

[0294] 1. Preparation of Coating Material Composition

[0295] An acrylic polyol (manufactured by Nuplex Resin, SETALUX 1753 (trade name), the resin content was 70% by mass, the hydroxyl value was 138.6 mgKOH/g) and each of polyisocyanate compositions were formulated such that the molar ratio of isocyanate group/hydroxyl group became 1.0. Then, ethyl acetate was added to the mixture such that the solid content became 50% by mass to obtain each coating material compositions.

[0296] 2. Preparation of Coating Film

[0297] Then, each of the resultant coating material compositions was coated on glass plates such that the dried film thickness became 40 m. Then, the resultant samples were cured at 23 C. and 50% RH to form coating film.

[0298] 3. Evaluation of Drying Property

[0299] After a predetermined time had elapsed since curing started, a cotton ball (having a cylindrical shape having a diameter of 2.5 cm and a high of 2.0 cm) was placed on the coating film and then a 100 g weight was placed thereon for 60 seconds. Then, the weight and the cotton ball were removed therefrom, and the imprint of the cotton ball on the coating film was observed. Then, the drying property was evaluated in accordance with the following evaluation criteria.

(Evaluation Criteria)

[0300] : The time required for the imprint to disappear completely was 8 hours or less.

[0301] : The time required for the imprint to disappear completely was more than 8 hours but 10 hours or less.

[0302] x: The time required for the imprint to disappear completely was more than 10 hours.

[Evaluation 4] Solvent Reducibility (Turbidity) of Coating Material Composition

[0303] 1. Preparation of Coating Material Composition

[0304] Each coating material compositions was obtained by the same method as that described in 1 in the [Evaluation 3].

[0305] 2. Evaluation of Solvent Reducibility (Turbidity)

[0306] Then, the turbidity of each resultant coating material composition was measured at 25 C. and at a measurement wavelength of 860 nm using a turbidity meter/chromatometer (manufactured by HACH, 2100 AN (trade name)). The solvent reducibility (turbidity) was evaluated based on the measurement results in accordance with the following evaluation criteria.

(Evaluation Criteria)

[0307] : 0.0 or more and less than 0.5

[0308] : 0.5 or more and less than 1.0

[0309] x: 1.0 or more

[Evaluation 5] Transparency of Coating Film

[0310] 1. Preparation of Coating Film

[0311] Coating material compositions having the following formulation were prepared. The resultant coating material compositions were coated on glass plates such that the dry film thickness thereof became 100 nm to 120 m. Then, the resultant plates were left at room temperature for 20 minutes, followed by baking the resultant plates at 120 C. for 30 minutes to form urethane coating films.

(Formulation of Coating Material Composition)

[0312] Each of polyisocyanate compositions obtained in Examples and Comparative Examples [0313] Polyol (Setalux 1767) [0314] Formulation ratio (NCO/OH=1.05) [0315] Diluent solvent: Butyl acetate [0316] Solid content in coating material: 50% by mass

[0317] 2. Evaluation of Transparency

[0318] A printed material was placed under the glass plate on which the resultant urethane coating film was laminated and then visually observed from above. The transparency was evaluated based on the readable degree of printed characters in accordance with the following evaluation criteria.

(Evaluation Criteria)

[0319] : Characters were clearly readable.

[0320] : Characters were slightly dulled.

[0321] x: Characters were unambiguously dulled.

[Evaluation 6] Resistance to Thermal-Yellowing Denaturation of Coating Film

[0322] 1. Preparation of Coating Film (Test Plate)

[0323] Coating material compositions formulated in the same manner as that of [evaluation 5] were prepared. Then, the resultant coating material compositions were coated on white tile plates such that the dried coating film thickness became 35 m. Then, the resultant white tile plates on which the coating material compositions were coated were placed horizontally, and then left still for 15 minutes. Then, the resultant plates were heated at 100 C. for 30 minutes to prepare test plates.

[0324] 2. Evaluation of Resistance to Thermal-Yellowing Denaturation

[0325] Then, the b-value (b1) of the resultant test plate was measured using a white standard plate with a measurement hole 50 mm using a SM color meter (SM-P45 type) manufactured by Suga Test Instruments Co., Ltd. Then, the test plate was stored in a dryer at 100 C., and the b-value (b2) thereof was measured every 1 week up to 8 weeks. The time required for the value obtained by (b2)(b1) to exceed 5 was measured. The resistance to thermal-yellowing denaturation was evaluated based on the obtained results in accordance with the following evaluation criteria.

(Evaluation Criteria)

[0326] : 8 weeks or more

[0327] : 4 weeks or more and less than 8 weeks

[0328] x: less than 4 weeks

[Evaluation 7] Odor Generated when Coating Film was Baked and Stored at a High-Temperature.

[0329] 1. Preparation of Coating Film (Test Plate)

[0330] Each coating material compositions was prepared in the same manner as that described in 1. of [Evaluation 3]. Then, the resultant coating material compositions were coated respectively on PET films (of which the thickness was 100 m) such that the dried film thickness became 40 m. Then, the PET films on which the coating material compositions were coated were placed horizontally and left still for 15 minutes. Then, the resultant films were heated in an oven at 100 C. for 30 minutes to obtain test plates.

[0331] 2. Odor Generated when Coating Film was Baked

[0332] The odor generated immediately after the test plates were heated at 100 C. for 30 minutes and then brought out from the oven was confirmed.

(Evaluation criteria) : The odor was slightly sensed.

[0333] x: The odor was strongly and unpleasantly sensed.

[0334] 3. Odor Generated when Coating Film was Stored at a High-Temperature.

[0335] The resultant test plates were cut into a size of 5 cm10 cm, rounded, and then put into screw glass bottles, followed by putting the lids thereon. Then, the resultant bottles were heated in an oven at 150 C. for 2 hours and removed therefrom. The lids of the removed screw bottles were opened, and the odor thereof was confirmed.

(Evaluation Criteria)

[0336] : The odor was slightly sensed.

[0337] x: The odor was strongly and unpleasantly sensed.

[Example 1] Preparation of Polyisocyanate Composition (PI-A1)

[0338] 100 parts by mass of 1,6-hexamethylene diisocyanate (hereinafter, may be abbreviated as HDI) was poured into a 1 L four-necked glass flask equipped with a thermometer, a stirrer and a nitrogen seal tube, and then the air in the flask was replaced with nitrogen, followed by heating the flask at 60 C. Then, 0.5 parts by mass of 2-ethylhexanol (hereinafter, may be abbreviated as 2-EHOH) was added to the resultant, and then stirred for 10 minutes. Then, an isobutanol (hereinafter, may be abbreviated as i-BuOH) solution containing 5% by mass of benzyltrimethylammonium caprate (hereinafter, may be abbreviated as BTMACA) was added to the resultant over 60 minutes such that the content of BTMACA became 0.005 parts by mass. The temperature during the reaction was controlled within a range of 602 C. When the desired NCO % was obtained, 0.005 parts by mass of dibutylphosphoric acid (hereinafter, may be abbreviated as DBP) was added to the resultant as a reaction-terminating agent, and then heated to 100 C. When the temperature reached 100 C., the resultant was stirred for 1 hour. The resultant reaction liquid was colorless and transparent. The reaction liquid was subjected to filtration using a membrane filter having a pore size of 1 m to obtain a reaction liquid. Then, the resultant reaction liquid was subjected to thin film distillation, and the resultant liquid was heated at 150 C. for 1 hour while stirring and irradiating the resultant liquid with UV intermittently under vacuum conditions (0.8 Torr). As the UV irradiation, 4 sets were conducted by repeating the following steps: irradiating the resultant liquid with UV (at 365 nm) for 5 minutes and then leaving the resultant liquid unirradiated for 10 minutes, as 1 set, after the temperature of the resultant liquid reached 150 C. Four sets of the UV irradiation were conducted. Then, the thin-film distillation was conducted again to obtain the polyisocyanate composition (PI-A1). The physical properties of the resultant polyisocyanate composition (PI-A1) were measured and evaluated by the above-mentioned methods. The results are shown in Table 1 indicated below.

[Examples 2 and 3 and Comparative Example 1] Preparation of Polyisocyanate Compositions (PI-A2), (PI-A3) and (PI-B1)

[0339] The reaction, termination treatment, filtration treatment and thin film distillation of reaction liquids were conducted in the same manner as that of Example 1. Then, the heating treatment was conducted under conditions shown in Table 1 indicated below. Then, the thin film distillation was conducted again to obtain polyisocyanate compositions (PI-A2), (PI-A3) and (PI-B1). The physical properties of the resultant polyisocyanate compositions (PI-A2), (PI-A3), and (PI-B1) were measured and evaluated by the above-mentioned methods. The results are shown in Table 1 indicated below.

[Example 4] Preparation of Polyisocyanate Composition (PI-A4)

[0340] 100 parts by mass of HDI was poured into a 1 L four-necked glass flask equipped with a thermometer, a stirrer and a nitrogen seal tube, and then the air in the flask was replaced with nitrogen, followed by heating the flask at 60 C. Then, 0.443 parts by mass of 2-EHOH was added to the resultant, and then stirred for 10 minutes. Then, an i-BuOH solution containing 5% by mass of BTMACA was added to the resultant over 60 minutes such that the content of BTMACA became 0.008 parts by mass. The temperature during the reaction was controlled within a range of 602 C. When the desired NCO % was obtained, 0.008 parts by mass of DBP was added to the resultant as a reaction-terminating agent, and then heated to 100 C. When the temperature reached 100 C., the resultant was stirred for 1 hour. The resultant reaction liquid was colorless and transparent. The reaction liquid was subjected to filtration using a membrane filter having a pore size of 1 m to obtain a reaction liquid. Then, the resultant reaction liquid was subjected to thin film distillation, and the resultant liquid was heated at 120 C. for 15 minutes while stirring and irradiating the resultant liquid with UV intermittently under vacuum conditions (0.8 Torr). As the UV irradiation, 1 set was conducted by irradiating the resultant liquid with UV (at 365 nm) for 5 minutes and then leaving the resultant liquid unirradiated for 10 minutes, after the temperature of the resultant liquid reached 150 C. Then, the thin-film distillation was conducted again to obtain the polyisocyanate composition (PI-A4). The physical properties of the resultant polyisocyanate composition (PI-A4) were measured and evaluated by the above-mentioned methods. The results are shown in Table 1 indicated below.

[Comparative Example 2] Preparation of Polyisocyanate Composition (PI-B2)

[0341] 100 parts by mass of HDI was poured into a 1 L four-necked glass flask equipped with a thermometer, a stirrer and a nitrogen seal tube, and then the air in the flask was replaced with nitrogen, followed by heating the flask at 60 C. Then, an i-BuOH solution containing 47% by mass of BTMACA was added over 60 minutes such that the content of BTMACA became 0.03 parts by mass. The temperature during the reaction was controlled within a range of 602 C. When the desired NCO % was obtained, 0.03 parts by mass of DBP was added to the resultant as a reaction-terminating agent, and then heated to 100 C. When the temperature reached 100 C., the resultant was stirred for 1 hour. The resultant reaction liquid was colorless and transparent. The reaction liquid was subjected to filtration using a membrane filter having a pore size of 1 m to obtain a reaction liquid. Then, the resultant reaction liquid was subjected to thin film distillation, and the resultant liquid was heated at 100 C. for 15 minutes while stirring and irradiating the resultant liquid with UV intermittently under vacuum conditions (0.8 Torr). As the UV irradiation, 1 set was conducted by irradiating the resultant liquid with UV (at 365 nm) for 5 minutes and then leaving the resultant liquid unirradiated for 10 minutes, after the temperature of the resultant liquid reached 100 C. Then, the thin-film distillation was conducted again to obtain the polyisocyanate composition (PI-B2). The physical properties of the resultant polyisocyanate composition (PI-B2) were measured and evaluated by the above-mentioned methods. The results are shown in Table 1 indicated below.

[Comparative Example 3] Preparation of Polyisocyanate Composition (PI-B3)

[0342] 100 parts by mass of HDI was poured into a 1 L four-necked glass flask equipped with a thermometer, a stirrer and a nitrogen seal tube, and then the air in the flask was replaced with nitrogen, followed by heating the flask at 60 C. Then, an i-BuOH solution containing 47% by mass of BTMACA was added over 60 minutes such that the content of BTMACA became 0.04 parts by mass. The temperature during the reaction was controlled within a range of 602 C. When the desired NCO % was obtained, 0.04 parts by mass of DBP was added to the resultant as a reaction-terminating agent, and then heated to 100 C. When the temperature reached 100 C., the resultant was stirred for 1 hour. The resultant reaction liquid was colorless and transparent. The reaction liquid was subjected to filtration using a membrane filter having a pore size of 1 m to obtain a reaction liquid. Then, the resultant reaction liquid was subjected to thin film distillation twice to obtain a polyisocyanate composition (PI-B3). The physical properties of the resultant polyisocyanate composition (PI-B3) were measured and evaluated by the above-mentioned methods. The results are shown in Table 1 indicated below.

[Comparative Example 4] Preparation of Polyisocyanate Composition (PI-B4)

[0343] 100 parts by mass of HDI was poured into a 1 L four-necked glass flask equipped with a thermometer, a stirrer and a nitrogen seal tube, and then the air in the flask was replaced with nitrogen, followed by heating the flask at 60 C. Then, 0.5 parts by mass of 2-EHOH was added to the resultant, and then stirred for 10 minutes. Then, an i-BuOH solution containing 5% by mass of BTMACA was added over 60 minutes such that the content of BTMACA became 0.005 parts by mass. The temperature during the reaction was controlled within a range of 602 C. When the desired NCO % was obtained, 0.005 parts by mass of DBP was added to the resultant as a reaction-terminating agent, and then heated to 100 C. When the temperature reached 100 C., the resultant was stirred for 1 hour. The resultant reaction liquid was colorless and transparent. The reaction liquid was subjected to filtration using a membrane filter having a pore size of 1 m to obtain a reaction liquid. Then, the resultant reaction liquid was subjected to thin film distillation, and the resultant liquid was heated at 150 C. for 1 hour while stirring the resultant liquid under vacuum conditions (0.8 Torr). Then, the thin film distillation was conducted again to obtain a polyisocyanate composition. The resultant polyisocyanate composition was irradiated with UV (at 365 nm) for 30 minutes to obtain a polyisocyanate composition (PI-B4). The physical properties of the resultant polyisocyanate composition (PI-B4) were measured and evaluated by the above-mentioned methods. The results are shown in Table 1 indicated below.

TABLE-US-00001 TABLE 1 Example 1 2 3 4 PI-Al PI-A2 PI-A3 PI-A4 Reaction temperature ( C.) 60 60 60 70 HDI (Parts by mass) 100.0 100.0 100.0 100.0 BTMACA (parts by mass) 0.005 0.005 0.005 0.008 i-BuOH (parts by mass) 0.095 0.095 0.095 0.152 2-EHOH (Parts by mass) 0.500 0.500 0.500 0.443 Heating Temperature ( C.) 150 120 120 120 treatment Time (minute) 60 60 30 15 Frequency of 4 sets 4 sets 2 sets 1 set UV irradiation Physical NCO% 21.9 22.0 22.0 22.0 property 1 Physical Viscosity (mPa.s) 2680 2610 2600 2650 property 2 Physical Nurate trimer (UV) (A) 100 100 100 100 property 4 Tetrameric equivalent 2 5 24 225 (UV) (B) (B)/(A) 0.02 0.05 0.24 2.25 Physical Volatile component 0.05 0.08 0.09 0.25 property 6 generated by storage at 60 C. for 3 months Evaluation 1 Color stability Evaluation 2 Viscosity stability Evaluation 3 Drying property of coating material composition Evaluation 4 Solvent reducibility of coating material composition Evaluation 5 Transparency of coating film Evaluation 6 Resistance to thermal-yellowing denaturation of coating film Evaluation 7 Odor generated when coating film was stored at a high temperature Odor generated when coating film was baked Comparative Example 1 2 3 4 PI-B1 PI-B2 PI-B3 PI-B4 Reaction temperature ( C.) 60 60 60 60 HDI (Parts by mass) 100.0 100.0 100.0 100.0 BTMACA (parts by mass) 0.005 0.030 0.040 0.005 i-BuOH (parts by mass) 0.095 0.034 0.045 0.095 2-EHOH (Parts by mass) 0.500 0.500 Heating Temperature ( C.) 150 100 150 treatment Time (minute) 90 15 60 Frequency of 6 sets 1 set 0 set UV irradiation Physical NCO% 21.9 21.9 21.9 21.9 property 1 Physical Viscosity (mPa.s) 2690 2720 2690 2700 property 2 Physical Nurate trimer (UV) (A) 100 100 100 100 property 4 Tetrameric equivalent 0.1 400 500 30 (UV) (B) (B)/(A) 0.001 4 5 0.3 Physical Volatile component <0.05 0.41 0.45 0.39 property 6 generated by storage at 60 C. for 3 months Evaluation 1 Color stability X Evaluation 2 Viscosity stability X X Evaluation 3 Drying property of X coating material composition Evaluation 4 Solvent X X reducibility of coating material composition Evaluation 5 Transparency of X X coating film Evaluation 6 Resistance to X thermal-yellowing denaturation of coating film Evaluation 7 Odor generated X X X when coating film was stored at a high temperature Odor generated X X X when coating film was baked

[0344] As shown in Table 1, the color stability and the viscosity stability of the polyisocyanate compositions PI-A1 to PI-A4 (Examples 1 to 4) were excellent. Furthermore, the coating material compositions containing these polyisocyanate compositions were favorable in terms of the drying property and the solvent reducibility. Furthermore, the coating films formed using these coating material compositions were favorable in terms of the transparency and the resistance to thermal-yellowing denaturation.

[0345] Furthermore, the polyisocyanate compositions PI-A2 and PI-A3 (Examples 2 and 3) were superior to the polyisocyanate compositions PI-A1 and PI-A4 (Examples 1 and 4), in terms of the color stability and the viscosity stability. Furthermore, the coating material compositions containing these polyisocyanate compositions were further favorable in terms of the solvent reducibility. Furthermore, the coating films formed using these coating material compositions were further favorable in terms of the transparency and the resistance to thermal-yellowing denaturation.

[0346] In contrast, the polyisocyanate compositions PI-B1 to PI-B3 (Comparative Examples 1 to 3) were inferior in terms of the color stability or the viscosity stability. Furthermore, the coating material compositions were also inferior in terms of the drying property or the solvent reducibility. Furthermore, the coating films were also inferior in terms of the transparency or the resistance to thermal-yellowing denaturation.

[0347] Furthermore, the coating film formed using the coating material composition containing the polyisocyanate composition PI-B4 (Comparative Example 4) generated strong and unpleasant odor when baked or stored under high-temperature conditions.

[0348] It was confirmed from the above-mentioned results that the polyisocyanate composition according to the present embodiment had excellent color stability and viscosity stability when stored under high-temperature conditions. Furthermore, it was confirmed that the resultant coating material composition had favorable drying property and solvent reducibility. Furthermore, it was confirmed that the resultant coating film had favorable transparency and resistance to thermal-yellowing denaturation.

INDUSTRIAL APPLICABILITY

[0349] The polyisocyanate composition according to the present embodiment is useful as a coating material, an adhesive, a sealant, a waterproof material, a foam, an elastomer, a fiber treatment agent, or the like.