JPH05279078A - Near infrared ray absorption material - Google Patents

Abstract

PURPOSE:To enable to easily recognize a material by allowing the material to contain a specified amount of phosphate compd. containing copper. CONSTITUTION:CuO and P2O5 are blended so as to provide a blended material in which molar ratio of CuO/P2O5 becomes 0.05-4 when copper is in terms of CuO and phosphoric acid is expressed in terms of P2O5. Then, after the blended material is dried at about 150 deg.C in an alumina crucible, etc., and calcined at about 800 deg.C, the material is powdered in a ball mill to provide a phosphoric acid compd. powder having <=100mum average particle diameter. Next, the powder is mixed with a dispersing medium, such as resin material, so that the powder content becomes >=10wt.% to produce a near infrared ray absorption material.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a near infrared ray absorbing material.

[0002]

2. Description of the Related Art Conventionally, since an object or an image has been recognized with the naked eye, a material that is easily recognized is a material that absorbs or scatters light in the visible light region. However, recently, a technique for automatically recognizing an object or an image has rapidly advanced. And as a light source for recognizing and reading this image,
It is said that semiconductor lasers will become the mainstream. As this semiconductor laser, one having a wavelength range of 700 to 1600 nm has been put into practical use, but this wavelength is in the near infrared region and cannot be visually recognized. Even an object or image that absorbs or scatters visible light well does not always absorb and scatter near infrared light well. The conventional material has a problem that it is difficult to recognize an object or an image in this near infrared region.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object thereof is to provide a near-infrared absorbing material which can be easily recognized by near-infrared rays. .

[0004]

The present invention provides a near infrared ray absorbing material containing 10% by weight or more of a phosphoric acid compound containing copper.

When the content of the copper-containing phosphoric acid compound in the near-infrared absorbing material of the present invention is less than 10% by weight, the near-infrared absorbing ability is insufficient. The larger the content of the phosphoric acid compound containing copper, the larger the near-infrared absorption capacity, which is preferable. On the other hand, the upper limit of the content is not particularly limited, but since the amount of the medium that binds this compound becomes relatively small and the strength of the material decreases, the upper limit of the content is limited depending on the application. It

In the phosphoric acid compound containing copper, copper is generally present as a copper compound. Copper compounds are generally
Although various colors such as black and brown are exhibited and each compound has a characteristic light absorption property, it has been found that particularly near-infrared rays are well absorbed in the phosphoric acid compound. As an index showing the copper concentration in the phosphoric acid compound, it is suitable to convert copper into CuO and phosphoric acid into P2 O5 and show it as a CuO / P2 O5 molar ratio, which is less than 0.05. In this case, the near-infrared absorbing ability is not sufficient, which is not preferable. Also, the higher the concentration of copper, the higher the near infrared absorption capacity, which is preferable,
If the molar ratio of CuO / P2 O5 exceeds 4, the phosphate compound becomes unstable, which is not preferable.

The phosphoric acid compound containing copper is not particularly limited, but as a material having a high near-infrared absorbing ability,
Examples of copper phosphates include copper metaphosphate, copper pyrophosphate, copper orthophosphate, copper apatite, and the like. In addition, various complex phosphates of copper and elements other than copper are also used, and by complex chlorination with elements other than copper, the near infrared absorptivity of this material, color tone,
It is also possible to control the refractive index and chemical properties. It is also known that these phosphates contain water of crystallization, and a compound containing water of crystallization is generally somewhat unfavorable in terms of chemical durability, but can be used depending on the application. Further, the phosphoric acid compound is not limited to a crystalline compound and can be used without problems even in an amorphous state such as glass.

As this glass, a phosphate glass containing 2.0 to 15% by weight of copper in terms of CuO is preferable.
When the copper concentration in the glass is less than 2.0% by weight in terms of CuO, the near-infrared absorbing ability is insufficient, which is not preferable. The higher the copper concentration is, the higher the near-infrared absorbing capacity is, which is preferable, but when the concentration in the glass exceeds 15% by weight in terms of CuO, the glass becomes unstable, which is not preferable.

The composition of this glass is not particularly limited, but as a composition having a high near-infrared absorbing ability, phosphoric acid containing 10 to 80% by weight of P2O5 and fluorine of 0 to 30% by weight in terms of P2O5. Salt glass or fluorophosphate glass is preferred. When the phosphoric acid concentration is less than 10% by weight in terms of P2O5, it is difficult to sufficiently dissolve the near-infrared absorbing component copper into the glass, and when it exceeds 80% by weight, the glass becomes hygroscopic and absorbs near-infrared rays. All of them are not preferable because the performance may deteriorate with time. Further, by containing fluorine, the near infrared absorbing ability can be improved. In this case, if the fluorine content in the glass exceeds 30% by weight, the glass becomes unstable, which is not preferable.

The method for producing the phosphoric acid compound is not particularly limited, and a general method for producing a phosphoric acid compound is appropriately used. A method of mixing a substance containing copper with a phosphoric acid compound and heating the mixture to carry out a solid phase reaction, A method in which a substance containing copper is dissolved in a solution containing phosphoric acid and then dried by heating, a method of melting a substance containing copper and phosphoric acid at 600 to 2000 ° C. to form a phosphoric acid compound, and the like can be used. .. In this case, copper exists in the phosphoric acid compound in two kinds of ionic states of monovalent and divalent, but since divalent copper ions contribute to near infrared absorption,
It is also effective to add an oxidizing agent having an oxidizing action during the production of the phosphoric acid compound or to synthesize the phosphoric acid compound in an oxidizing atmosphere to enhance the near-infrared absorption ability of the phosphoric acid compound.

There are no particular restrictions on the particle size of this phosphoric acid compound when made into a powder, but there may be an appropriate particle size depending on the application. If you want to recognize fine shapes and patterns,
The phosphoric acid compound powder preferably has a small particle size. Generally, the average particle size is preferably 100 μm or less. There is no limitation on the method for powdering the phosphoric acid compound, but a general method is used as a method for producing a powdered phosphoric acid compound such as pulverization by a ball mill.

The medium for dispersing the phosphoric acid compound powder is not particularly limited, and the phosphoric acid compound powder is appropriately dispersed,
A material that is relatively transparent to near-infrared rays so that the near-infrared absorbing ability of the phosphoric acid compound is exhibited is preferable. Depending on the application,
A material in which the refractive index of the phosphoric acid compound matches that of visible light is preferable because it becomes a material transparent to visible light.
When used at room temperature, a resin material can be generally used as this medium.

There is no limitation on the method of dispersing the phosphoric acid compound powder. When dispersing the powder of the phosphoric acid compound, in the case of dispersing in the resin material, the method of evaporating the solvent after dispersing in the resin solution, or the method of dispersing the resin in the low molecular weight resin and then dispersing the resin A method of polymerizing, a method of mixing resin powder with a phosphoric acid compound powder and then heating and sintering, and the like can be appropriately used.

The form of the near-infrared absorbing material in which the phosphoric acid compound powder is dispersed is not particularly limited and can be appropriately selected depending on the application. The material can be used as a molded body of the material itself, but the object can also be achieved by applying the material on the surface of an article to be recognized. In this case, since the near-infrared absorbing material of the present invention is substantially colorless and transparent to visible light, it is possible to effectively absorb only near-infrared light without impairing the appearance of the base material with the naked eye. Further, by applying or printing this material on a base material in a pattern, it becomes possible to perform printing which can be effectively read by near infrared light.

[0015]

【Example】

Example 1 A solution prepared by diluting 100 parts by weight of 85% phosphoric acid with water three times was heated, and then 69 parts by weight of copper oxide (CuO) was added. This amount corresponds to a molar ratio of CuO / P2 O5 of 2 when copper is converted to CuO and phosphoric acid is converted to P2 O5. After sufficiently stirring, the mixture was transferred to an alumina crucible, dried at 150 ° C., and calcined at 800 ° C. The fired product was crushed with a ball mill to obtain a powder. The average particle size of the powder was 2.8 μm. To 40 parts by weight of this powder, an α-terpineol solution in which 20% by weight of ethyl cellulose was dissolved was added at a ratio of 60 parts by weight, kneaded, and homogenously dispersed by a three-roll mill, adjusted to a desired viscosity, and formed into a paste form. An ink composition of

This ink was screen-printed on a half surface of a 4-inch square alumina plate and dried. The printed film thickness after drying was about 15 μm. The printed part was slightly light green. Semiconductor laser with this plate (wavelength: 810
The reflectance of the printed portion was about 18% of the reflectance of the alumina substrate.

Example 2 A solution prepared by diluting 100 parts by weight of 85% phosphoric acid by 3 times with water was heated, and then copper oxide (Cu
O) 34.5 parts by weight and zinc oxide (ZnO) 35.3
Parts by weight were added. This amount is CuO for copper and P2 for phosphoric acid.
The CuO / P2 O5 molar ratio corresponds to 1 in terms of O5. A powder was obtained in the same manner as in Example 1 below. The average particle size of the powder was 2.4 μm. This powder was treated in the same manner as in Example 1 to obtain a paste-like ink composition.

This ink was screen-printed on a half-inch surface of a 4-inch square alumina plate and dried. The printed film thickness after drying was about 25 μm. The printed portion was almost white, and there was almost no difference in appearance from the alumina of the substrate. Semiconductor laser with this plate (wavelength: 810 nm)
The reflectance of the printed portion was about 22% of the reflectance of the alumina substrate.

[Example 3] 100 parts by weight of ammonium dihydrogen phosphate (NH4 H2 PO4) powder and copper oxide (Cu)
O) Powder 103.7 parts by weight was mixed to obtain a mixed powder. This amount is equivalent to Cu when Cu is converted to CuO and phosphoric acid is converted to P2 O5.
The molar ratio O / P2 O5 corresponds to 3. This mixed powder was transferred to an alumina crucible and fired at 900 ° C. The fired product was crushed with a ball mill to obtain a powder. The average particle size of the powder was 2.3 μm. This powder was treated in the same manner as in Example 1 to obtain a paste-like ink composition.

This ink was screen-printed on a half surface of a 4-inch square alumina plate and dried. The printed film thickness after drying was about 20 μm. The printed part had a light green color. Semiconductor laser with this plate (wavelength: 810n
As a result of measuring the reflectance for m), the reflectance of the printed portion was about 8% of the reflectance of the alumina substrate.

Example 4 Phosphate glass powder having the composition and particle size characteristics shown in Table 1 (CuO for copper and P2 O for phosphoric acid)
(The molar ratio of CuO / P2O5 converted to 5 corresponds to 0.067) is added to 80 parts by weight of an α-terpineol solution in which 10% by weight of ethylcellulose is dissolved, and the mixture is kneaded. Homogeneous dispersion was performed with a three-roll mill to adjust the paste viscosity to a desired value, and a paste-like ceramic color composition was obtained.

[0022]

[Table 1]

This paste was screen-printed on a half surface of a 4-inch square alumina plate and dried. The printed film thickness after drying was about 40 μm. The printed part was slightly blue in color, but there was almost no difference in appearance from the alumina of the substrate. Semiconductor laser (wavelength:
As a result of measuring the reflectance with respect to 810 nm), the reflectance of the printed portion was about 10% of the reflectance of the alumina substrate.

Example 5 To 15 parts by weight of a phosphate glass powder having the composition and average particle size shown in Table 2, 85 parts by weight of acrylic resin powder was heat kneaded, and then 4 cm square, 3 m
It was formed into a m-thick plate. Further, a plate was prepared in the same manner using quartz powder having an average particle size of about 1.5 μm.

[0025]

[Table 2]

The plate using quartz powder was colorless, and the plate using phosphate glass powder was slightly greenish blue, but both plates were slightly cloudy but transparent. As a result of measuring the reflectance of these plates with respect to the semiconductor laser (wavelength: 810 nm), the reflectance of the plate using the phosphoric acid glass powder was about 22% of the reflectance of the plate using the quartz powder.

[Comparative Example] The same phosphoric acid glass powder as in Example 5 (CuO / CuO in terms of CuO / P2O5).
The molar ratio of P2 O5 corresponds to 1) to 93 parts by weight of 93
After heating and kneading parts by weight of acrylic resin powder, 4 cm
It was formed into a plate having a square shape and a thickness of 3 mm. Further, a plate was manufactured in the same manner with quartz powder as in Example 4.

The plate using quartz powder was colorless, and the plate using phosphate glass powder was slightly greenish blue, and both were slightly cloudy but transparent. As a result of measuring the reflectance of these plates with respect to the semiconductor laser (wavelength: 810 nm), the reflectance of the plate using the phosphoric acid glass powder is about 62% of the reflectance of the plate using quartz powder. Absorption was inadequate.

[0029]

The near-infrared absorbing material of the present invention satisfactorily absorbs a semiconductor laser in the near-infrared region, so that a system using this light source can satisfactorily recognize it as an object or an image.

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[Procedure amendment]

[Submission date] October 23, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

In the phosphoric acid compound containing copper, copper is generally present as a copper compound. Copper compounds are generally
Although various colors such as black and brown are exhibited and each compound has a characteristic light absorption property, it has been found that particularly near-infrared rays are well absorbed in the phosphoric acid compound. As an index showing the copper concentration in the phosphoric acid compound, it is suitable to convert copper into CuO and phosphoric acid into P ₂ O ₅ and show the molar ratio of CuO / P ₂ O ₅ , and this molar ratio is 0. If it is less than 0.05, the near-infrared absorbing ability is not sufficient, which is not preferable. Also, the higher the concentration of copper, the higher the near infrared absorption capacity, which is preferable,
When the molar ratio of CuO / P ₂ O ₅ exceeds 4, the phosphoric acid compound becomes unstable, which is not preferable.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

The composition of this glass is not particularly limited, but as the composition having a high near-infrared absorbing ability, phosphoric acid is contained in an amount of 10 to 80% by weight and fluorine is included in an amount of 0 to 30% by weight in terms of P ₂ O _5. Phosphate glass or fluorophosphate glass is preferred. When the phosphoric acid concentration is less than 10% by weight in terms of P ₂ O ₅ , it is difficult to sufficiently dissolve the near infrared ray absorbing component copper into the glass, and when it exceeds 80% by weight, the glass becomes hygroscopic. Both are not preferable because the infrared absorption capacity may deteriorate with time. Further, the incorporation of fluorine can improve the near infrared absorbing ability. In this case, if the fluorine content in the glass exceeds 30% by weight, the glass becomes unstable, which is not preferable.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

[0015]

Example 1 After heating a solution prepared by diluting 100 parts by weight of 85% phosphoric acid with water three times, 69 parts by weight of copper oxide (CuO) was added. This amount, copper CuO, the molar ratio of CuO / P ₂ O ₅ in terms of the phosphoric acid P ₂ O ₅ is equivalent to 2. After sufficiently stirring, the mixture was transferred to an alumina crucible, dried at 150 ° C., and calcined at 800 ° C. The fired product was crushed with a ball mill to obtain a powder. The average particle size of the powder was 2.8 μm. To 40 parts by weight of this powder, an α-terpineol solution in which 20% by weight of ethyl cellulose was dissolved was added at a ratio of 60 parts by weight, kneaded, and homogenously dispersed by a three-roll mill, adjusted to a desired viscosity, and formed into a paste form. An ink composition of

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Example 2 A solution prepared by diluting 100 parts by weight of 85% phosphoric acid by 3 times with water was heated, and then copper oxide (Cu
O) 34.5 parts by weight and zinc oxide (ZnO) 35.3
Parts by weight were added. This amount is CuO for copper and P _{2 for} phosphoric acid.
In terms of O ₅ molar ratio of CuO / P ₂ O ₅ is equivalent to 1. A powder was obtained in the same manner as in Example 1 below. The average particle size of the powder was 2.4 μm. This powder was treated in the same manner as in Example 1 to obtain a paste-like ink composition.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

Example 3 100 parts by weight of ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ) powder and copper oxide (Cu)
O) Powder 103.7 parts by weight was mixed to obtain a mixed powder. This amount is equivalent to Cu when copper is converted to CuO and phosphoric acid is converted to P ₂ O _5.
The molar ratio O / P ₂ O ₅ corresponds to 3. This mixed powder was transferred to an alumina crucible and fired at 900 ° C. The fired product was crushed with a ball mill to obtain a powder. The average particle size of the powder was 2.3 μm. This powder was treated in the same manner as in Example 1 to obtain a paste-like ink composition.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Example 4 Phosphate glass powder having the composition and particle size characteristics shown in Table 1 (CuO for copper and P ₂ O for phosphoric acid)
₅ molar ratio in terms of CuO / P ₂ O ₅ is to 80 parts by weight or equivalent) to 0.067, the addition of α- terpineol solution of 10 wt% ethylcellulose in a proportion of 30 parts by kneading Then, uniform dispersion was performed with a three-roll mill to adjust to a desired paste viscosity, and a paste-like ceramic color composition was obtained.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

[0022]

[Table 1]

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025]

[Table 2]

[Procedure Amendment 10]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

[0027] [Comparative Example] Example 5 and CuO same phosphate glass powder (copper, CuO in terms of phosphoric acid P ₂ O ₅ /
The molar ratio of P ₂ O ₅ is equivalent to 1) and the amount of
After heating and kneading parts by weight of acrylic resin powder, 4 cm
It was formed into a plate having a corner of 3 mm. Further, a plate was manufactured in the same manner with quartz powder as in Example 4.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takuo Osuga 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Asahi Glass Co., Ltd.

Claims (3)

[Claims] 1. A near infrared absorbing material containing 10% by weight or more of a phosphoric acid compound containing copper. 2. A phosphoric acid compound is CuO for copper and P for phosphoric acid.
The molar ratio of CuO / P2 O5 is 0.05 when converted to 2 O5.
The near infrared ray absorbing material according to claim 1, wherein 3. The near infrared absorbing material according to claim 2, wherein the phosphoric acid compound contains zinc in an amount of 0.5% by weight or more in terms of ZnO.