Patent Number: 
Section: description

The present invention will hereinafter be described specifically by the following examples. However, the present invention is not limited by these examples. A four-necked flask was equipped with a stirrer, a thermometer and a condenser and charged with 1-methoxy-2-propanol (270 g; 3.0 mol) and toluene (400 g) as a solvent, and the resultant mixture was cooled to 5xc2x0 C. with stirring. Phosphorus pentoxide (142 g; 1.0 mol) was then gradually added to the resultant solution while keeping the temperature of the solution at 5 to 10xc2x0 C. Thereafter, the temperature of the solution was gradually raised to react 1-methoxy-2-propanol with phosphorus pentoxide under conditions of 60xc2x0 C. and 6 hours. Water (20 g) was added to the resultant reaction mixture, and the resultant mixture was stirred at 80xc2x0 C. for 2 hours. After the condenser installed in the four-necked flask was replaced by a distiller, toluene and water contained in the reaction mixture were removed by the distiller, thereby obtaining a liquid reaction product (390 g). With respect to the reaction product thus obtained, spectroscopic analysis was performed by an infrared absorption spectrum. As a result, it was confirmed that the reaction product contains a phosphate compound represented by the formula (m) and a phosphate compound represented by the formula (n). The infrared absorption curve of this reaction product is illustrated in FIG. 1. With respect to the reaction product thus obtained, the compositions and yield of the phosphate compounds were calculated out in the following manner. [Composition of Phosphate Compounds] An Autotitrator COMTITE-101 manufactured by Hiranuma Sangyo K. K. was used to conduct neutralization titration of the reaction product, and the contents of the phosphate compound represented by the formula (m) and the phosphate compound represented by the formula (n) were respectively calculated out from the titers at the resultant first inflection point and second inflection point. The results are shown in Table 1. [Yield] Concentrated nitric acid and perchloric acid were added to the reaction product and the reaction product was decomposed under heat. After distilled water was added to the decomposition product to dilute it, nitric acid, a 0.25% aqueous solution of ammonium vanadate and a 5% aqueous solution of ammonium molybdate were added to the resultant solution to develop a color, thereby measuring an absorbance at a wavelength of 440 nm by means of a spectrophotometer to find a concentration (% by weight) of phosphorus in the reaction products based on the absorbance of a standard solution of phosphorus. The yield was calculated out from this concentration of phosphorus and a concentration (% by weight) of phosphorus in the phosphorus compound used. The result is shown in Table 1. A four-necked flask was equipped with a stirrer, a thermometer, a condenser to which a water scrubber had been connected, and a dropping funnel, and charged with phosphorus oxychloride (153 g; 1.0 mol), titanium tetrachloride (4.6 g) as a catalyst and toluene (180 g) as a solvent, and the resultant mixture was cooled to 5xc2x0 C. with stirring. After 1-methoxy-2-propanol (180 g; 2.0 mol) was added to the resultant solution, triethylamine (202 g; 2.0 mol) was added to the solution over 2 hours while keeping the temperature of the solution at 5 to 15xc2x0 C. The temperature of the solution was gradually raised to react 1-methoxy-2-propanol with phosphorus oxychloride under conditions of 50xc2x0 C. and 2 hours. Water (200 g) was then added to the resultant reaction mixture and hydrolysis of the reaction product was conducted under conditions of 50xc2x0 C. and 1 hour. The resultant reaction mixture was left at rest, thereby separating the reaction mixture into a toluene layer and a water layer. Thereafter, the toluene solution was recovered. Toluene (100 g) was then added to the residual aqueous solution to conduct an extraction treatment of the reaction product contained in the aqueous solution, and a toluene solution was recovered. This process was conducted repeatedly 3 times, thereby recovering the toluene solution in an amount of 600 g in total. After the condenser installed in the four-necked flask was replaced by a distiller, a treatment for removing toluene and the like from the toluene solution was conducted by this distiller, thereby obtaining a liquid reaction product (165 g). With respect to the reaction product thus obtained, spectroscopic analysis was performed by an infrared absorption spectrum. As a result, it was confirmed that the reaction product contains a phosphate compound represented by the formula (m) and a phosphate compound represented by the formula (n). The infrared absorption curve of this reaction product is illustrated in FIG. 2. With respect to the reaction product thus obtained, the composition and yield of the phosphate compounds were calculated out in the same manner as in Example 1. The results are shown in Table 1. (1) Preparation of Phosphonate Compound A four-necked flask was equipped with a stirrer, a thermometer, a condenser to which a water scrubber had been connected, and a dropping funnel, and charged with phosphorus trichloride (275 g; 2.0 mol) and hexane (200 g) as a solvent, and the resultant mixture was heated to 50xc2x0 C. 1-Methoxy-2-propanol (540 g; 6.0 mol) was then added to the resultant solution over 2 hours while keeping the temperature of the solution at 50 to 70xc2x0 C. Hydrogen chloride generated upon the addition of 1-methoxy-2-propanol in the above-described process was introduced into the water scrubber to recover it. After completion of the addition of 1-methoxy-2-propanol, the interior of the four-necked flask was sucked at 60xc2x0 C. for 1 hour under a reduced pressure of 500 mmHg, thereby conducting a treatment for removing remaining hydrogen chloride. After the condenser installed in the four-necked flask was replaced by a distiller, a treatment for removing hexane and 1-methoxy-2-chloropropane, which was a reaction by-product, in the reaction mixture was conducted by this distiller. The residue was further distilled under reduced pressure, and a distillate at 119.0 to 125.0xc2x0 C. under 3 mmHg was recovered, thereby obtaining a liquid product (398 g). This liquid product was analyzed by gas chromatography. As a result, the purity (calculated out by an area ratio in a chart) of the bis(2-methoxy-1-methylethyl) hydrogen-phosphonate was 96.3%. (2) Preparation of Phosphate Compound A four-necked flask was equipped with a stirrer, a thermometer, a condenser to which a 5% aqueous sodium hydroxide scrubber had been connected, and a dip tube for introducing chlorine gas, and charged with the above-obtained liquid product (226 g; about 1.0 mol as bis(2-methoxy-1-methylethyl) hydrogenphosphonate), and the contents were cooled to 10xc2x0 C. Chlorine gas was blown into bis(2-methoxy-1-methylethyl) hydrogenphosphonate while the temperature thereof was kept at 10 to 20xc2x0 C., and the introduction of chlorine gas was continued until the solution was slightly colored yellow. Thereafter, the interior of the four-necked flask was sucked at 25xc2x0 C. under a reduced pressure of 15 mmHg, thereby conducting a treatment for removing excess chlorine gas and hydrogen chloride, which was a reaction by-product, to obtain a liquid product (263 g). This liquid product was analyzed by gas chromatography. As a result, the purity (calculated out by an area ratio in a chart) of the bis(2-methoxy-1-methylethyl) phosphorochloridate was 92.4%. A concentration of chlorine in the liquid product was measured in accordance with xe2x80x9cDetermination Method of Chloride Ion by Silver Nitrate Standard Solutionxe2x80x9d described in xe2x80x9cExperimental Methods of Analytical Chemistryxe2x80x9d (published by Kagakudojin K. K.). As a result, the concentration of chlorine was 14.3%. Water (90 g; 5.0 mol) was added to the resultant liquid product, and the temperature of this solution was gradually raised to conduct hydrolysis of bis(2-methoxy-1-methylethyl) phosphorochloridate under conditions of 40xc2x0 C. and 2 hours. After the condenser installed in the four-necked flask was replaced by a distiller, a treatment for removing water from the reaction mixture was conducted by this distiller, thereby obtaining a reaction product (234 g). With respect to the reaction product thus obtained, spectroscopic analysis was performed by an infrared absorption spectrum. As a result, it was confirmed that the reaction product contains a phosphate compound represented by the formula (m) and a phosphate compound represented by the formula (n). The infrared absorption curve of this reaction product is illustrated in FIG. 3. With respect to the reaction product thus obtained, the composition and yield of the phosphate compounds were calculated out in the same manner as in Example 1. The results are shown in Table 1. (1) Preparation of Phosphonate Compound A four-necked flask was equipped with a stirrer, a thermometer, a condenser to which a water scrubber had been connected, and a dropping funnel, and charged with phosphorus trichloride (137.5 g; 1.0 mol) and hexane (300 g) as a solvent, and the resultant mixture was heated to 50xc2x0 C. Dipropylene glycol monomethyl ether (444 g; 3.0 mol) was then added to the resultant solution over 2 hours while keeping the temperature of the solution at 50 to 70xc2x0 C. Hydrogen chloride generated upon the addition of dipropylene glycol monomethyl ether in the above-described process was introduced into the water scrubber to recover it. After completion of the addition of dipropylene glycol monomethyl ether, the interior of the four-necked flask was sucked at 60xc2x0 C. for 3 hours under a reduced pressure of 500 mmHg, thereby conducting a treatment for removing remaining hydrogen chloride. After the condenser installed in the four-necked flask was replaced by a distiller, a treatment for removing hexane in the reaction mixture was conducted by this distiller, thereby obtaining a liquid mixture (504 g) of a phosphonate compound of dipropylene glycol monomethyl ether and a chloride of dipropylene glycol monomethyl ether, which was a reaction by-product. This liquid mixture was analyzed by gel permeation chromatography. As a result, the purity (calculated out by an area ratio in a chart) of the phosphonate compound was 72.2%. (2) Preparation of Phosphate Compound A four-necked flask was equipped with a stirrer, a thermometer, a condenser to which a 5% aqueous sodium hydroxide scrubber had been connected, and a dip tube for introducing chlorine gas, and charged with the above-obtained liquid mixture (504 g), and the contents were cooled to 10xc2x0 C. Chlorine gas was blown into this liquid mixture while the temperature thereof was kept at 10 to 20xc2x0 C., and the introduction of chlorine gas was continued until the solution was slightly colored yellow. Thereafter, the interior of the four-necked flask was sucked at 25xc2x0 C. under a reduced pressure of 15 mmHg, thereby conducting a treatment for removing excess chlorine gas and hydrogen chloride, which was a reaction by-product, to obtain a mixture (546 g) of a phosphorochloridate of dipropylene glycol monomethyl ether and a chloride of dipropylene glycol monomethyl ether. This mixture was analyzed by gel permeation chromatography. As a result, the purity (calculated out by an area ratio in a chart) of the phosphorochloridate was 69.9%. A concentration of chlorine in the mixture was measured in the same manner as in Example 3. As a result, the concentration of chlorine was 9.3%. Water (128 g; 7.0 mol) was added to the resultant mixture, and the temperature of this solution was gradually raised to conduct hydrolysis of the phosphorochloridate of dipropylene glycol monomethyl ether under conditions of 50xc2x0 C. and 2 hours. After the condenser installed in the four-necked flask was replaced by a distiller, steam distillation was conducted by this distiller under a reduced pressure or 20 mmHg while introducing steam from the dip tube, thereby conducting a treatment for removing water and the chloride of dipropylene glycol monomethyl ether from the reaction liquid to obtain a reaction product (348 g). With respect to the reaction product thus obtained, spectroscopic analysis was performed by an infrared absorption spectrum. As a result, it was confirmed that the reaction product contains a phosphate compound represented by the formula (o) and a phosphate compound represented by the formula (p). The infrared absorption curve of this reaction product is illustrated in FIG. 4. With respect to the reaction product thus obtained, the composition and yield of the phosphate compounds were calculated out in the same manner as in Example 1. The results are shown in Table 1. A process was performed in the same manner as in Example 4 except that tripropylene glycol monomethyl ether (3.0 mol) was used in place of dipropylene glycol monomethyl ether, thereby obtaining a reaction product (424 g). With respect to the reaction product thus obtained, spectroscopic analysis was performed by an infrared absorption spectrum. As a result, it was confirmed that the reaction product contains a phosphate compound represented by the formula (q) and a phosphate compound represented by the formula (r). The infrared absorption curve of this reaction product is illustrated in FIG. 5. With respect to the reaction product thus obtained, the composition and yield of the phosphate compounds were calculated out in the same manner as in Example 1. The results are shown in Table 1.  less than Preparation of Resin Composition greater than  The phosphate compound (hereinafter referred to as xe2x80x9cEster Axe2x80x9d) obtained in Example 3, the phosphate compound (hereinafter referred to as xe2x80x9cEster Bxe2x80x9d) obtained in Example 4 and the phosphate compound (hereinafter referred to as xe2x80x9cEster Cxe2x80x9d) obtained in Example 5 were separately used to prepare resin compositions in the following manner. The phosphate compound and methyl methacrylate were mixed in accordance with their corresponding formulations shown in Table 2. Anhydrous copper benzoate was added to the resultant mixtures, and stirring and mixing were conducted at 60xc2x0 C. for 1 hour, thereby preparing monomer compositions. t-Butyl peroxypivalate (0.2 g) was added to the monomer compositions, and the resultant mixtures were successively heated at different temperatures of 45xc2x0 C. for 16 hours, 60xc2x0 C. for 8 hours and 90xc2x0 C. for 3 hours to polymerize the methyl methacrylate, thereby preparing resin compositions (1) to (3) containing respective near infrared ray absorbers (phosphate compound and copper ion) according to the present invention.  less than Evaluation of Resin Composition greater than  The resin compositions (1) to (3) thus obtained were press-molded at 200xc2x0 C., thereby obtaining blue and transparent plates having a thickness of 4 mm. With respect to the plates thus obtained, the light transmittances at wavelengths of 550 nm, 800 nm and 900 nm were measured. The plates thus obtained were subjected to a 500-hour weathering test by means of a sunshine weathermeter (black panel temperature: 63xc2x0 C., precipitated), and the light transmittances of the plates after the test were measured to investigate the plates as to whether the light transmittances were changed or not. The results are shown in Table 2. As apparent from the results shown in Table 2, it was confirmed that the resin compositions (1) to (3) containing the respective near infrared ray absorbers according to the present invention have excellent visible ray-transmitting property and performance that near infrared rays are absorbed with high efficiency, and are little in the deterioration of their near infrared ray-absorbing ability by ultraviolet rays. The compound (0.14 g) represented by the above formula (a) and the compound (0.80 g) represented by the above formula (b) as specific phosphate compounds were added into methyl methacrylate (20 g) to mix them. Anhydrous copper benzoate (1.17 g) was added to the mixture solution, and the resultant mixture was stirred at 60xc2x0 C. for 1 hour, thereby reacting the phosphate compounds with anhydrous copper benzoate to prepare a monomer composition containing the specific phosphate copper compounds. t-Butyl peroxypivalate (0.2 g) was added to the monomer composition thus obtained, and the resultant mixture was successively heated at different temperatures of 45xc2x0 C. for 16 hours, 60xc2x0 C. for 8 hours and 90xc2x0 C. for 3 hours to polymerize the methyl methacrylate, thereby preparing an acrylic resin composition. The acrylic resin composition obtained in the above-described manner was evaluated. The acrylic resin composition was press-molded at 200xc2x0 C., thereby obtaining a blue and transparent plate having a thickness of 4 mm. With respect to the plate thus obtained, the light transmittances at wavelengths of 550 nm, 800 nm and 900 nm were measured. The plate thus obtained was subjected to a 500-hour weathering test by means of a sunshine weathermeter (black panel temperature: 63xc2x0 C., precipitated), and the light transmittances of the plate after the test were measured to investigate the plate as to whether the light transmittances were changed or not. The results are shown in Table 3. The spectral transmittance curve of the plate is illustrated in FIG. 6. The compounds represented by the above formula (a) to the formula (r) were provided as specific phosphate compounds (these compounds will hereinafter be referred to as xe2x80x9cEster (a)xe2x80x9d to xe2x80x9cEster (r)xe2x80x9d, respectively) to perform a process in the same manner as in Example 6 except that the specific phosphate compounds and copper salts were used in accordance with their corresponding formulations shown in following Table 3, thereby preparing acrylic resin compositions to evaluate them. The results are shown in Table 3. A four-necked flask was equipped with a stirrer, a thermometer and a condenser and charged with Ester (n) (242 g; 1.0 mol) as the specific phosphate compound, toluene (250 g) as a solvent and copper acetate monohydrate (100 g; 0.5 mol). The temperature of the mixture was gradually raised, and the mixture was stirred at 40xc2x0 C. for 1 hour and further at 80xc2x0 C. for 3 hours, thereby reacting the specific phosphate compound with copper acetate monohydrate to obtain a blue and transparent solution. The solution was subjected to a distillation treatment to remove acetic acid formed by the reaction of the specific phosphate compound with copper acetate monohydrate and toluene, thereby obtaining a phosphate copper compound (270 g) according to the present invention. The yield was 99.0%. The thus-obtained phosphate copper compound had a structure represented by the following formula (8). The phosphate copper compound was analyzed. As a result, the content of phosphorus was 11.40% by weight (theoretical value: 11.35% by weight), and the content of copper was 11.70% by weight (theoretical value: 11.64% by weight). This compound had no clear melting point, and its decomposition temperature was 247xc2x0 C. Incidentally, the infrared absorption curve of the phosphate copper compound thus obtained is illustrated in FIG. 7.  The phosphate copper compound (1 g) and Ester (n) (1.03 g) were added to methyl methacrylate (20 g), and stirring and mixing were conducted at 60xc2x0 C. for 1 hour, thereby obtaining a blue and transparent monomer composition. t-Butyl peroxypivalate (0.3 g) was added to the monomer composition thus obtained, and the resultant mixture was successively heated at different temperatures of 45xc2x0 C. for 16 hours, 60xc2x0 C. for 8 hours and 90xc2x0 C. for 3 hours to polymerize the methyl methacrylate, thereby preparing an acrylic resin composition containing the phosphate copper compound according to the present invention. The resin composition was evaluated in the same manner as in Example 6. The results are shown in Table 4. A four-necked flask was equipped with a stirrer, a thermometer and a condenser and charged with Ester (p) (358 g; 1.0 mol) as the specific phosphate compound, toluene (360 g) as a solvent and copper acetate monohydrate (100 g; 0.5 mol). The temperature of the mixture was gradually raised, and the mixture was stirred at 40xc2x0 C. for 1 hour and further at 80xc2x0 C. for 3 hours, thereby reacting the specific phosphate compound with copper acetate monohydrate to obtain a blue and transparent solution. The solution was subjected to a distillation treatment to remove acetic acid formed by the reaction of the specific phosphate compound with copper acetate monohydrate and toluene, thereby obtaining a phosphate copper compound (355 g) according to the present invention. The yield was 91.3%. The thus-obtained phosphate copper compound had a structure represented by the following formula (9) and was in the form of a jelly solid. The phosphate copper compound was analyzed. As a result, the content of phosphorus was 8.03% by weight (theoretical value: 7.96% by weight), and the content of copper was 8.20% by weight (theoretical value: 8.17% by weight). Incidentally, the infrared absorption curve of the phosphate copper compound thus obtained is illustrated in FIG. 8.  The phosphate copper compound (1 g) and Ester (p) (1.08 g) were added to methyl methacrylate (20 g), and stirring and mixing were conducted at 60xc2x0 C. for 1 hour, thereby obtaining a blue and transparent methyl methacrylate solution. The thus-obtained methyl methacrylate solution was used to conduct a process in the same manner as in Example 18, thereby preparing an acrylic resin composition containing the phosphate copper compound according to the present invention to evaluate it. The results are shown in Table 4. A four-necked flask was equipped with a stirrer, a thermometer and a condenser and charged with Ester (r) (475 g; 1.0 mol) as the specific phosphate compound, toluene (480 g) as a solvent and copper acetate monohydrate (100 g; 0.5 mol). The temperature of the mixture was gradually raised, and the mixture was stirred at 40xc2x0 C. for 1 hour and further at 80xc2x0 C. for 3 hours, thereby reacting the specific phosphate compound with copper acetate monohydrate to obtain a blue and transparent solution. The solution was subjected to a distillation treatment to remove acetic acid formed by the reaction of the specific phosphate compound with copper acetate monohydrate and toluene, thereby obtaining a phosphate copper compound (455 g) according to the present invention. The yield was 90.0%. The thus-obtained phosphate copper compound had a structure represented by the following formula (10) and was in the form of a viscous liquid. The phosphate copper compound was analyzed. As a result, the content of phosphorus was 6.20% by weight (theoretical value: 6.13% by weight), and the content of copper was 6.33% by weight (theoretical value: 6.29% by weight). Incidentally, the infrared absorption curve of the phosphate copper compound thus obtained is illustrated in FIG. 9.  The phosphate copper compound (1 g) and Ester (r) (1.18 g) were added to methyl methacrylate (20 g), and stirring and mixing were conducted at 60xc2x0 C. for 1 hour, thereby obtaining a blue and transparent methyl methacrylate solution. The thus-obtained methyl methacrylate solution was used to conduct a process in the same manner as in Example 18, thereby preparing an acrylic resin composition containing the phosphate copper compound according to the present invention to evaluate it. The results are shown in Table 4. Ester (c) (0.4 g) and Ester (d) (1.6 g) as the specific phosphate compounds and anhydrous copper benzoate (1.3 g) were added to toluene (20 g), and the resultant mixture was stirred and mixed at 60xc2x0 C. for 1 hour, thereby reacting the specific phosphate compounds with anhydrous copper benzoate to obtain a blue and transparent toluene solution containing the phosphate copper compounds according to the present invention. The whole amount of the toluene solution was added to polymethyl methacrylate beads (xe2x80x9cMHGAxe2x80x9d, product of Sumitomo Chemical Co., Ltd.; 40 g) to stir and mix them. Thereafter, the resultant mixture was dried under reduced pressure at 60xc2x0 C. for 24 hours to conduct a treatment for removing toluene, thereby obtaining a massive product. The massive product was ground and then kneaded for 5 minutes by rolls heated to 180xc2x0 C., thereby obtaining a blue and transparent resin composition. The resin composition was press-molded, thereby producing a plate having a thickness of 2 mm to evaluate it in the same manner as in Example 6. The results are shown in Table 4. As apparent from the results shown in Tables 3 and 4, it was confirmed that the resin compositions containing the respective phosphate copper compounds according to the present invention have excellent visible ray-transmitting property and performance that near infrared rays are absorbed with high efficiency, and are little in the deterioration of their near infrared ray-absorbing ability by ultraviolet rays. A four-necked flask was equipped with a stirrer, a thermometer and a condenser and charged with Ester (n) (242 g; 1.0 mol) as the specific phosphate compound and toluene (250 g) as a solvent. The mixture was cooled to 5xc2x0 C., and 25% aqueous sodium hydroxide (160 g, 1.0 mol as sodium hydroxide) was gradually added to the solution while keeping the temperature of the solution at 5 to 20xc2x0 C., thereby neutralizing Ester (n). Thereafter, an aqueous solution with copper (II) sulfate pentahydrate (250 g; 1 mol) dissolved in water (750 g) was added to this solution over 1 hour while keeping the temperature of the solution at 20xc2x0 C. The temperature of the solution was gradually raised to react Ester (n) with copper (II) sulfate under conditions of 80xc2x0 C. and 5 hours. After sodium sulfate and sodium copper (II) sulfate formed in the reaction mixture were removed by filtration, the reaction mixture was left at rest, thereby separating the reaction mixture into a toluene layer and a water layer to recover the toluene solution. Toluene (200 g) was then added to the residual aqueous solution to conduct an extraction treatment of the reaction product contained in the aqueous solution, and a toluene solution was recovered. This process was conducted repeatedly 3 times, thereby recovering the toluene solution in an amount of 1020 g in total. After the condenser installed in the four-necked flask was replaced by a distiller, a treatment for removing toluene and the like from the toluene solution was conducted by this distiller, thereby obtaining a reaction product (180 g). The yield was 66.0%. The thus-obtained phosphate copper compound had the structure represented by the above formula (8). The phosphate copper compound was analyzed. As a result, the content of phosphorus was 11.26% by weight (theoretical value: 11.35% by weight), and the content of copper was 11.04% by weight (theoretical value: 11.64% by weight). This compound had no clear melting point, and its decomposition temperature was 240xc2x0 C. Incidentally, the infrared absorption curve of the phosphate copper compound thus obtained is illustrated in FIG. 10. According to the phosphate compounds of the present invention, a copper ion can be dispersed in a high proportion in a synthetic resin, since they have a hydroxyl group capable of being tonically or coordinately bonded to the copper ion, and are good in compatibility with synthetic resins, for example, acrylic resins. Accordingly, the phosphate compounds according to the present invention are suitable for use as additives for resins for dispersing a copper ion in synthetic resins. According to the process of the present invention for preparing a phosphate compound, the phosphate compound can be prepared with advantages. The phosphate copper compounds according to the present invention have performance that near infrared rays are absorbed with high efficiency, and are little in the deterioration of its near infrared ray-absorbing ability by ultraviolet rays and satisfactory in compatibility with synthetic resins, for example, acrylic resins. According to the process of the present invention for preparing a phosphate copper compound, the phosphate copper compound can be prepared with advantages. According to the near infrared ray absorbers of the present invention, a copper ion, which is a near infrared ray-absorbing component, can be dispersed in a high proportion in a synthetic resin because the above-mentioned phosphate compound is contained therein, and the resin compositions, to which the near infrared ray absorber according to the present invention is added, have excellent visible ray-transmitting property and performance that near infrared rays are absorbed with high efficiency and are little in the deterioration of its near infrared ray-absorbing ability by ultraviolet rays. According to the near infrared ray absorbers of the present invention, resin compositions, which have performance that near infrared rays are absorbed with high efficiency and are little in the deterioration of its near infrared ray-absorbing ability by ultraviolet rays and excellent in visible ray-transmitting property, can be provided by containing such an absorber in a synthetic resin, since the near infrared ray absorbers comprise the phosphate copper compound as an effective ingredient. The near infrared ray-absorbing acrylic resin compositions according to the present invention have excellent visible ray-transmitting property and performance that near infrared rays are absorbed with high efficiency and are little in the deterioration of its near infrared ray-absorbing ability by ultraviolet rays.