JPH05255606A - Preparation of dye-containing. coating liquid - Google Patents

Abstract

PURPOSE:To obtain the subject coating liquid excellent in physical properties of the film therefrom, useful for e.g. optical recording disks by dispersing a dye into ultrafine particles to obtain a dispersion followed by centrifugation to eliminate particles of relatively large size to effect specified particle size quickly. CONSTITUTION:A dye of e.g. phthalocyanine base is dispersed into ultrafine particles to obtain a dispersion, which is, in turn, centrifugalized e.g. at 10000-150000rpm and 15-25 deg.C to eliminate such dye particles as to have a diameter larger than the thickness of the dye coating film, thus giving the objective coating liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a dye-containing coating liquid used for forming a dye coating film used for optical recording disks, chemical substance sensors and the like.

[0002]

2. Description of the Related Art Recently, various optical recording disks such as a write-once type and a rewritable type have been attracting attention as a large capacity information carrying medium.

Some of such optical recording disks use a recording layer containing a dye as a main component. Further, in terms of structure, a so-called air sandwich structure in which an air layer is provided on a dye layer which has been generally used in the past, or a reflective layer on the dye layer as a reproducible one that complies with the Compact Disc (CD) standard is provided. A structure provided in close contact has been proposed (Nikkei Electronics January 23, 1989 issue, No. 465, P107, Kinki Chemical Society Functional Dye Subcommittee, March 3, 1989, Osaka Science and Technology). Center, PROCEEDINGS SPIE-THE INTERNATIONAL SOCIETY F
OR OPTICAL ENGINEERING VOL.1078 PP80-87, "OPTICAL D
ATA STORAGE TOPICAL MEETING "17-19, JANUARY 1989 LOS
ANGELES etc.).

On the other hand, a specific chemical substance existing in the outside world is selectively adsorbed or selectively reacted therewith, and the type and concentration of the chemical substance is detected from the change in electric signal such as resistivity or dielectric constant. There are known chemical sensors.

Under these circumstances, a sensor utilizing the reflection of a dye film has been proposed as a simple device structure and easy manufacture, and specifically, a mixed film of a chemical substance sensitive compound and a dye is proposed. Examples of the sensor film include a sensor film and a laminated film in which a chemical substance-sensitive compound film (sensor film) and a dye film are laminated. By binding a test chemical substance such as water to the chemical substance-sensitive compound, Examples thereof include those configured to detect the changing reflectance of the dye film (JP-A-2-169449, JP-A-2-19304).
No. 5).

The dye film used in the above-mentioned optical recording disk or sensor is usually formed by coating such as spin coating using a coating liquid containing a dye.

Therefore, in the preparation of the dye-containing coating liquid, the type of the solvent that can be used is limited depending on the substrate material, the solubility of the dye in the solvent is required, and the combination of the dye and the solvent used is limited. Further, since a coating solution having a concentration higher than the solubility cannot be prepared, there is a drawback that a good coating film cannot be obtained with a dye having a low solubility.

[0008] From such an actual situation, the applicant has previously
A proposal has been made to form a dye coating film using an ultrafine particle dispersion liquid of the dye (Japanese Patent Application No. 3-318397 and 3).
-333900).

However, when a dispersion liquid is prepared by such an ultrafine particle dispersion method, pigment particles having a large particle diameter are likely to be present in the dispersion liquid, and in particular, pigment particles having a particle diameter exceeding the film thickness of the dye film are used. If particles are present, there is a problem that a good film cannot be obtained.

If a good film is not obtained, it will not show good characteristics when used as an optical recording disk or sensor.

As a solution to such a problem, it is possible to separate pigment particles having a large particle diameter by a filter at the time of coating.

However, such a method is complicated because it is necessary to replace the filter frequently. Further, the filter is apt to cause clogging, which is disadvantageous in terms of time.

[0013]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a dye coating film having excellent physical properties, which enables the dye particles to be rapidly made into a particle size of a predetermined size in an ultrafine particle dispersion liquid of the dye. It is to provide a method for preparing a dye-containing coating liquid that enables formation.

[0014]

These objects are achieved by the present invention described in (1) to (6) below.

(1) In the method for preparing a dye-containing coating liquid used for forming a dye coating film, the dye is dispersed in ultrafine particles to obtain a dispersion liquid, which is then centrifuged to obtain a particle A method for preparing a dye-containing coating liquid, which comprises removing large dye particles.

(2) The method for preparing a dye-containing coating solution according to (1) above, wherein at least dye particles having a particle size larger than the film thickness of the dye coating film are removed.

(3) The method for preparing a dye-containing coating solution according to (1) or (2) above, wherein the ultrafine particles of the dye are dispersed by colliding a dispersion containing a dye raw material under high pressure with each other. ..

(4) The method for preparing a dye-containing coating solution as described in any one of (1) to (3) above, which is used for spin coating.

(5) The method for preparing a dye-containing coating liquid according to any one of (1) to (4) above, which is used for forming a dye coating film which is a recording layer of an optical disc.

(6) The method according to any one of (1) to (4) above, which is used for forming a dye coating film of a chemical substance sensor constructed so that the light reflectance of the dye coating film changes depending on the chemical substance to be tested. A method for preparing a dye-containing coating liquid.

[0021]

[Specific Structure] The specific structure of the present invention will be described in detail below. In the present invention, the pigment is dispersed in ultrafine particles to obtain an ultrafine particle dispersion of the pigment.

Since such a dispersion liquid is used, unlike a normal coating liquid prepared by dissolving a dye in a solvent, it is not necessary to consider the solubility of the dye in the solvent, and the range of selection of the dye is widened. The dye can be used as it is. Therefore, it is not necessary to use a derivative such as a solubilized structure,
The dye structure is simple and the stability is improved. Further, the dye content in the dispersion liquid can be increased, and the film thickness of the dye film as the recording layer can be increased.

The dispersion liquid of the dye as described above is obtained by colliding the dispersion liquids containing the dye raw material (the average particle diameter of the dye is about 500 to 2000 A) pressurized under high pressure with each other. Specifically, the pigment raw material-containing dispersion is passed through a nanomizer. The nanomizer divides the flow path of the pigment raw material-containing dispersion liquid fed under pressure into two, collides the pigment raw material-containing dispersion liquids with each other, and pulverizes the pigment raw material.
It is to be dispersed in a dispersion medium, and a commercially available device [eg,
"Nanomizer System" manufactured by Nanomizer Co., Ltd.] can be used. The pressure applied to the pigment raw material-containing dispersion liquid at this time is about 200 to 1400 kg / cm ² . Moreover, in order to enhance the crushing effect, it is preferable to cool the entire apparatus by using liquid nitrogen or the like.

FIG. 1 is an exploded perspective view for explaining an example of the structure of the nanomizer.

As shown in FIG. 1, the nanomizer 10 is
Two discs 11 (front disc) and 12
It has a (rear disc), and the front disc side retainer 13 is provided in front of the front disc 11, and the rear disc 1
Rear disc-side restraints 14 are installed behind 2 respectively.

The front disk 11 has two through holes 1
A connection groove (orifice) 112 that connects 11 and the two holes 111 is provided. On the other hand, the rear disc 12
The two through holes 121 and a connecting groove (orifice) 122 that connects the two through holes 121 are provided in the. The front disk 11 and the rear disk 12 are set with the connecting groove 112 and the connecting groove 122 being 90 degrees in phase with each other so as to form a cross shape.

In the configuration of FIG. 1, the front disc 1
The pigment raw material-containing dispersion liquid pressurized by a high-pressure pump or the like is pressure-fed from the first side, and the two holes 1
It is divided into two parts by 11 and is accelerated, and the flat surface of the rear disk 12 and the connecting groove 1 of the front disk 11
The pigment raw material-containing dispersion liquid, which is directed from the two holes 111 toward the central portion at the same time to the orifice constituted by 12, is further accelerated to reach the maximum flow velocity, and the pigment raw material-containing dispersion liquids collide with each other, and at the same time, the pigment raw material is crushed and dispersed. The medium is dispersed in the medium, and this is instantly completed, and the connecting groove 122 and the front disc 11 of the rear disc 12 formed in 90 degrees in phase.
The prepared ultrafine particle dispersion liquid is discharged from the rear disk 12 side from the orifice formed of the flat surface via the two holes 122 of the rear disk 12.

The maximum flow velocity in the orifice is, for example, 300
It is about m / sec, and the transit time in the nanomizer is, for example, about 1/300000 sec.

In the present invention, the ultrafine particle dispersion liquid of the dye prepared as described above is subjected to centrifugation.

With this, the pigment particles having a large particle diameter can be precipitated and separated by utilizing the difference in the buoyant density, and only the pigment particles having a predetermined particle diameter or less can be present in the dispersion liquid. it can.

Centrifugation may be carried out using a commercially available centrifuge. The conditions are rotation speeds of 5000 to 20.
0000, preferably 10,000 to 150,000, and a temperature of 10 to 30 ° C., preferably 15 to 25 ° C. The dispersion medium used in the dispersion liquid may be selected according to the dye, and will be described later.

The treatment by the centrifuge may be a batch treatment or a continuous treatment.

The amount of liquid per batch in the batch treatment is usually 5 to 200 ml. Further, the supply amount in the continuous treatment is 5 to 200 ml / min.

In the dispersion liquid after centrifugation, pigment particles having a particle diameter of a predetermined value or less are present, and the particle diameter at this time may be selected according to the purpose and application.

In general, it is preferable that the maximum particle diameter of the pigment particles existing in the above-mentioned dispersion is small, and the maximum particle diameter (r) is equal to or less than the film thickness (d) of the pigment coating film, and further 1 / 2
It is preferably d or less.

The maximum particle size (r) is usually 500-
It is 2500 A and the average particle size is about 5 to 500 A.

Therefore, in the present invention, the pigment particles having a particle size exceeding the above maximum particle size (r) may be centrifuged.
At a minimum, the pigment particles exceeding the film thickness (d) may be removed. Such removal can be easily performed by selecting the conditions of centrifugation within the above range. Also,
Since only centrifugation is performed, the operation is simple and quick.

The above particle size is based on the ultrafine particle size analyzer BI-
90 (manufactured by Brookhaven Instruments Co., Ltd.) was measured in a liquid, and is considered to be maintained in the dye coating film.

The ultrafine particle size analyzer obtains the particle size from the time change of fluctuation of the scattering of laser light, and the particle size is automatically measured from the refractive index and viscosity of the solvent.

By setting the maximum particle size of the dye as described above, a uniform film can be obtained. On the other hand, if the maximum particle size becomes too large, diffuse reflection occurs, the reflectance fluctuates greatly, and a uniform film cannot be obtained.

In the present invention, the thus-prepared ultrafine particle dispersion liquid of the dye is used as a dye-containing coating liquid and applied onto a predetermined substrate or the like. The coating method is not particularly limited, but spin coating is preferable.

In the present invention, the ultrafine particle dispersion liquid of the dye may be continuously centrifuged, and then the dye-containing coating liquid may be directly used for spin coating.

FIG. 2 shows a structural example of an apparatus for preparing such a coating solution and performing spin coating.

The apparatus shown in FIG. 2 is based on the nanomizer 1 described above.
0, a storage tank 20 for storing the ultrafine particle dispersion liquid of the dye prepared by the Nanomizer 10 via the liquid supply pipe 41, a storage tank 20
It has a centrifuge 30 that introduces the above-mentioned dispersion liquid through a liquid supply pipe 42 and centrifuges it, and a spin coating section 50 that performs spin coating.

The centrifuge 30 is of a continuous processing type. A pipe 43 and a pump 51 with a switch are installed between the centrifuge 30 and the spin coat section 50.

The spin coating section 50 mounts the substrate 2 of an optical recording disk, which is the object of spin coating, and has a predetermined rotation speed (150 to 4000 rp) during spin coating.
a spinner 55 rotating at m) and a coating port 53 for applying and coating the dye-containing coating liquid after centrifugation, which is taken out in a fixed amount by the operation of the pump 41, to the substrate 2 via the valve 54. Have.

An apparatus having such a configuration is advantageous because it can perform a consistent treatment of dispersion of ultrafine particles of dye, centrifugation and spin coating.

In the present invention, the centrifuge 30 in the configuration of FIG. 2 is not limited to the configuration of FIG. 2 such as a batch type, and various modifications can be made within the scope of the present invention.

The dye-containing coating liquid of the present invention is mainly used for an optical recording disk having a recording layer containing a dye or a chemical substance sensor constructed so that the light reflectance of a dye coating film is changed depending on a chemical substance to be detected. It is used for forming a dye coating film.

Therefore, the dye of the present invention can absorb light.
It means a reflective material, specifically a pigment or dye, and there is no particular limitation on such a pigment or dye.

Among these, the absorption maximum is 600-9.
It is preferable to use a light absorbing dye having a wavelength of 00 nm, preferably 600 to 800 nm, more preferably 650 to 750 nm, and particularly preferably a phthalocyanine type, naphthalocyanine type, cyanine type, pyrylium type, squarylium type, croconium type, azurenium type, Other than cyanine-based compounds, polymethine-based compounds, azo-based compounds, triphenylmethane-based compounds, quinone or anthraquinone-based compounds, metal complex-based compounds such as dithiol metal complexes and indoaniline metal complexes, etc. may be mentioned.

It is preferable to use one or more selected from these.

The dispersion medium in which these dyes are dispersed preferably has a boiling point of 80 ° C. to 260 ° C., and is generally suitable for the spin coating method, and is used for forming and drying the dye coating film. Those having an appropriate evaporation rate under dry conditions are preferable.

Specifically, ketone systems such as cyclohexanone, methyl ethyl ketone and methyl butyl ketone, ester systems such as ethyl acetate and butyl acetate, halogenated hydrocarbon systems such as dichloroethane, methylcyclohexane,
There are hydrocarbons such as decalin.

In addition, aliphatic alcohols such as propanol and butanol, keto alcohols such as diacetone alcohol, alcohols such as fluorinated alcohols and acetylene alcohols, alcohol ethers such as cellosolve and ethyl cellosolve, penta. Fluoropropanol, a chlorofluorocarbon solvent, etc. can also be used. Among them, diacetone alcohol, ethyl cellosolve, cyclohexanone, methylcyclohexane and the like are preferably used.

The content of the dye in the dye-containing coating liquid of the present invention can be 2 to 10 wt% of the whole coating liquid. It is preferably 3 to 8 wt% for an optical recording disk and 2 to 6 wt% for a chemical substance sensor. With such a content, the film thickness of the dye coating film becomes sufficient, and sufficient reflectance can be obtained, resulting in excellent film physical properties.

When two or more dyes are used in combination, the total content should be within the above range.

When it is necessary to add a solid component other than the dye to the dye-containing coating liquid, this component may be added during dispersion of the ultrafine particles, and centrifugation may be performed in the same manner as the dye particles. ..

Examples of such a material include a surfactant. This is added in order to prevent re-aggregation of the dye that has been made into ultrafine particles, and is particularly preferably added in the case of an optical recording disk.

As such a surfactant, a nonionic surfactant is preferable, and it is particularly preferable to use an ethylene glycol derivative [eg, polyoxyethylene (20) sorbitan monostearate] for the stability of the dispersion liquid. It is preferable for the purpose. Further, a fluorine-based nonionic surfactant can also be used. Furthermore, soluble dyes can be used instead of surfactants, as described below.

The content of such a surfactant in the dispersion is about 0.005 to 0.6 wt% with respect to the entire dispersion.

Further, in the present invention, a binder may be used in place of the surfactant, and the content of the binder in the whole dispersion is about 0.005 to 0.6 wt%.

Further, a surfactant and a binder may be used in combination.

As such a binder, a compound having a highly polar portion such as polymethylmethacrylate (PMMA) or vinyl acetate, an acrylic ester having a vinyl group at the terminal, a methacrylic ester, acrylamide, N-alkyl is used. Acrylamide, styrenesulfonic acid, acrylic acid, methacrylic acid, N, N-dialkylaminoethyl acrylate, N, N-dimethylaminopropyl acrylamide, acryloylmorpholine,
Examples of the polymerizable compound include hydroxyethyl methacrylate, N-vinylpyrrolidone, N, N-methylenebisacrylamide, triethylene glycol bismethacrylate and the like.

It is desirable that such a binder be dissolved in the ultrafine particle dispersion liquid, but it may be contained as ultrafine particles of 1 / 5λ or less.

Further, such a binder may be in a state of being bound with a dye.

Next, an optical recording disk having a dye coating film (hereinafter also referred to as "dye film") formed using the dye-containing coating liquid of the present invention as a recording layer will be described.

In this case, the fluctuation of the reflectance of the unrecorded portion (non-pit forming portion) in the dye film is small, and the fluctuation width is 5/100 or less, preferably 2/100 or less of the reflectance, and the smaller the smaller. preferable. Therefore, noise is reduced. In addition, the C / N ratio of the recording part with pits is 40 dB.
That is all. The same applies to the case where the reflective layer is laminated in close contact with the dye film.

As described above, since the fluctuation of the reflectance of the unrecorded portion is small, the noise level is reduced and the signal after recording can be increased. On the other hand, if the fluctuation of the reflectance of the unrecorded portion becomes large, noise increases.

The reflectance in the above is for the dye film before recording, and for the laminated film of the dye film / reflection layer when the reflective layer is laminated. For example, in the case of a CD standard optical recording disk having a reflective layer, a Yamaha PDS recording / reproducing device is used to obtain a linear velocity of 1.3.
790nm when tracking the groove at m / s
The fluctuation range of the reflection level with respect to the ground level is 5/100 or less. At this time, a tracking signal is sufficiently obtained, and the S / N ratio becomes high.

The reflectance at the wavelength of 790 nm at this time is about 20 to 75%. By application, it is about 20 to 40% for a single layer film and about 60 to 75% for a CD.

In the case of forming such a dye film, the dye-containing coating liquid of the present invention further contains, in addition to the dye in which ultrafine particles are dispersed, 0.1 to 2 wt% of another soluble dye for filling the space between particles. You may mix about%. In this case, the soluble dye is preferably added in advance at the time of dispersing the ultrafine particles, but in some cases, it may be added after preparing the coating solution. Further, a part of the pigment dispersed in the ultrafine particles may be dissolved in the liquid. At this time, the amount of the dye in the dissolved state may be 0.1 wt% or more of the whole, and is usually about 0.1 to 4 wt%. When a soluble dye is separately used, the closer the refractive indices (n) are to each other, the more the optical homogeneity is obtained, and the soluble dye or the dye in the dissolved state is in an amorphous state, and in the dye film in an amount in the above range, Since the dye exists between the ultrafine particles, the bond between the particles becomes strong, and the film property and the adhesion of the film to the substrate are improved. Also, the dispersibility is increased. The refractive index of the ultrafine particles Dye (n ₁₎ and the refractive index of an amorphous state of the soluble dye (n ₂₎ and the reproduction wavelength (λ) | n ₁ -
It is preferable that n ₂ | ≦ 0.5, preferably 0.2. It should be noted that n is obtained in a film state, and can be obtained by a known method (see Kyoritsu Zensho "Optical" Kozo Ishiguro P168-178 etc.) and has the same meaning as in the optical recording disc of the CD standard described later. ..

Further, in the present invention, the light absorbing dye and the quencher may be mixed and used. Further, an ionic combination of a dye cation and a quencher anion may be used as the light absorbing dye.

As the quencher, acetylacetonate type, bisdithiol type such as bisdithio-α-diketone type and bisphenyldithiol type, thiocatechol type, salicylaldehyde oxime type and thiobisphenolate type metal complex are preferable. .. Further, amine compounds having a nitrogen radical cation and amine quenchers such as hindered amines are also suitable.

The dye constituting the conjugate is preferably a cyanine dye having an indolenine ring, and the quencher is preferably a metal complex dye such as bisphenyldithiol metal complex.

Details of preferable dyes, quenchers and conjugates are disclosed in JP-A-59-24692 and 59-55.
No. 794, No. 59-55795, No. 59-81194.
No. 59-83695, No. 60-18387, No. 60-19586, No. 60-19587, No. 60-
35054, 60-36190, 60-361.
No. 91, No. 60-44554, No. 60-44555.
No. 60, No. 60-44389, No. 60-44390, No. 60-47069, No. 60-20991, No. 60-.
No. 71294, No. 60-54892, No. 60-712.
No. 95, No. 60-71296, No. 60-73891.
No. 60, No. 60-73892, No. 60-73893, No. 60-83892, No. 60-85449, No. 60-
92893, 60-159087, 60-16
No. 2691, No. 60-203488, No. 60-201.
No. 988, No. 60-234886, No. 60-2348.
No. 92, No. 61-16894, No. 61-11292
No. 61-11294, No. 61-16891, No. 61-8384, No. 61-14988, No. 61-1.
63243, 61-210539, Japanese Patent Application No. 60-
No. 54013, JP-A Nos. 62-30088 and 62-3.
No. 2132, No. 62-31792, CMC Publishing "Chemistry of Functional Dyes" P74-76 and the like.

The quencher may be added separately from the light absorbing dye or in the form of a conjugate, but it is 1 mol or less, particularly 0.05 mol or less per 1 mol of the total light absorbing dye. ~
It is preferable to add about 0.5 mol. This allows
Light resistance is improved.

As described above, when used as a mixture with a quencher or when a conjugate with a quencher is used, the dye may be contained in the above proportion.

The film thickness of the recording layer formed using the dye-containing coating solution of the present invention may be determined according to the purpose and application, but the dry film thickness is 500 to 3000 A, preferably a single layer film. For 600-800A, for CD-1800A
It is possible to build a layer of 3000A.

FIG. 3 shows an example of the structure of an optical recording disk having such a recording layer on a substrate. FIG. 3 is a partial sectional view.

The optical recording disk 1 shown in FIG. 3 is a contact type optical recording disk which has a reflective layer in close contact with the recording layer and which is capable of reproduction in accordance with the CD standard.

As shown in the figure, the optical recording disc 1 has a recording layer 3 containing a dye as a main component on the surface of the substrate 2 and is in close contact with the recording layer 3 to form a reflective layer 4 and a protective film. Have 5.

The substrate 2 has a disk shape, and in order to enable recording and reproduction from the back side of the substrate 2,
Recording light and reproducing light (semiconductor laser light having a wavelength of about 600 to 900 nm, particularly about 770 to 900 nm, especially 7
Substantially transparent to 80 nm (preferably a transmittance of 88)
% Or more) resin or glass.

The size is about 64-200 mm in diameter and about 1.2 mm in thickness.

Grooves 23 for tracking are formed on the surface of the substrate 2 on which the recording layer 3 is formed, as shown in FIG.
The groove 23 is preferably a spiral continuous groove having a depth of 0.1 to 0.25 μm, a width of 0.35 to 0.50 μm, and a groove pitch of 1.5 to.
It is preferably 1.7 μm. With such a configuration of the groove, a good tracking signal can be obtained without lowering the reflection level of the groove portion.

Particularly, the groove width is 0.35 to 0.50 μm.
It is important to regulate the groove width to 0.35μ.
If it is less than m, it is difficult to obtain a sufficiently large tracking signal, and jitter is likely to increase due to a slight tracking offset during recording. Also 0.5
If it exceeds 0 μm, waveform distortion of the reproduced signal is likely to occur,
This will increase the black stroke.

As the material of the substrate 2, it is preferable to use resin, and various thermoplastic resins such as polycarbonate resin, acrylic resin, amorphous polyolefin and TPX are preferable. Then, the resin can be manufactured by a known method such as injection molding. The groove 23 is preferably formed when the substrate 2 is molded. After the substrate 2 is manufactured, the groove 23 is formed by the 2P method or the like.
You may form the resin layer which has.

As shown in FIG. 3, the recording layer 3 provided on the substrate 2 is formed by using the above-mentioned ultrafine particle dispersion liquid, and preferably by a method according to the spin coating method as described above. It is a thing.

The thickness of the recording layer 3 thus formed is preferably 500 to 3000 A as a dry film thickness. Outside this range, the reflectance decreases and it becomes difficult to perform reproduction in accordance with the CD standard.

At this time, the film thickness of the recording layer 3 in the recording track in the groove 23 is set to 2000 A or more, particularly 2000 to 3
At 000A, the degree of modulation becomes extremely large.

The recording layer 3 thus formed is C
When recording a D signal, the extinction coefficient (imaginary part of complex refractive index) k at the wavelengths of the recording light and the reproducing light is 0.02 to
It is preferably 0.05. When k is less than 0.02, the absorptivity of the recording layer is lowered, and it is difficult to perform recording with normal recording power. Further, when k exceeds 0.05, the reflectance falls below 70%, making it difficult to perform reproduction according to the CD standard.

The refractive index (real part of complex refractive index) n of the recording layer 3 is 2.0 to 2.6. When n <2.0, the reflectance decreases and the reproduction signal becomes small, so that reproduction according to the CD standard tends to be difficult.

The dye used in the recording layer may be selected from the above light-absorbing dyes, dye-quencher mixtures and dye-quencher conjugates having n and k in the above range. In some cases, the molecule can be newly designed and synthesized.

Further, in the recording layer 3, the values of n and k can be adjusted to values in the above range by compatibilizing two or more kinds of dyes. This can also improve the wavelength dependence.

As shown in FIG. 3, on the recording layer 3,
The reflective layer 4 is provided by directly adhering. As the reflective layer 4, it is preferable to use a high reflectance metal or alloy such as Au or Cu. The reflective layer 4 preferably has a thickness of 500 A or more, and may be formed by vapor deposition, sputtering or the like. Although the upper limit of the thickness is not particularly limited, it is preferably about 1200 A or less in consideration of cost, production work time and the like. Accordingly, the reflectance of the reflective layer 4 alone is 9
0% or more, the reflectance of the unrecorded part of the medium through the substrate is
60% or more, particularly 70% or more can be obtained.

As shown in FIG. 3, on the reflective layer 4,
The protective film 5 is provided. The protective film 5 is made of various resin materials such as an ultraviolet curable resin, and is usually 0.5 to 100 μm.
The layer may be formed to a thickness of about m. The protective film 5 may be layered or sheet-shaped. The protective film 5 may be formed by a usual method such as spin coating, gravure coating, spray coating, or dipping.

The optical recording disk to which the present invention is applied is not limited to the contact type optical recording disk as shown in the drawing, but may be any one as long as it has a recording layer containing a dye.

Examples of such a material include a pit forming type optical recording disk having an air sandwich structure.

Further, a chemical substance sensor using a dye film formed by using the dye-containing coating liquid of the present invention will be described.

The dye film at this time is a sensor film in which the dye itself is a chemical substance sensitive compound that interacts with the test chemical substance, but a film containing another chemical substance sensitive compound different from the dye is laminated. The sensor film may be a member of the laminated film thus formed, or may be a mixed film in which another chemical substance-sensitive compound is mixed.

The reflectance, particularly the specular reflectance, of such a dye film is 10% when measured at an angle of 20 ° or less, particularly 5 °, particularly at any wavelength in the visible to infrared region. As described above, it is preferable to have a so-called bronze gloss of 20% or more. The upper limit of reflectance is generally about 60%.

The dye film of the present invention may have an absorption rate of 70% or less, preferably 50% or less,
It is desirable that the maximum wavelength of reflection (λR _max ) in the dye film be different from the maximum wavelength of absorption (λA _max ), and it is particularly desirable that λR _max −λA _max ≧ 50 nm.

By using such a dye film, substantially sufficient sensitivity can be obtained. This is because if the reflectance is less than 10%, it will be difficult to detect it as a reflectance change. Further, the sensitivity is increased by measuring the reflectance due to the specular reflection of 20 ° or less, and the device can be made compact.

On the other hand, the chemical substance to be tested in the present invention is not particularly limited, and examples thereof include water, NOx, SOx, NH ₃ , amines, alcohols and various other gases. The chemical substance to be tested is preferably gaseous, but may be liquid in some cases.

In the present invention, such a chemical substance to be tested is brought into contact with a chemically sensitive compound to cause an interaction such as a bond between them, and this interaction causes the physical properties of the dye film. Change. Then, this change in the physical properties of the film changes the light reflectance of the dye film, particularly the specular reflectance, and the chemical substance to be detected is detected and quantified by detecting the change in the light reflectance.

A soluble dye may be used as in the case of the optical recording disk.

Further, similarly, a part of the dye dispersed in the ultrafine particles may be dissolved, and the amount of the dye in the dissolved state at this time may be 0.1 wt% or more of the whole, usually 0.1 to 0.1% by weight.
It is about 3 wt%.

Further, a mixture or a combination of a light absorbing dye and a quencher may be used.

The film thickness of the dye film at this time may be selected according to the required sensitivity, but it is set to about 400 to 2000 A, and usually about 400 to 1000 A, and the film thickness that maximizes the reflectance is used. Is preferred.

In the present invention, when the dye is a chemical substance-sensitive compound, a dye that interacts with a chemical substance to be tested may be selected from the dyes mentioned above and used.

In the dye film formed by using the soluble dye in addition to the ultrafine dye particles, one or both of the dye in the ultrafine dye particles and the soluble dye can be the chemical substance sensitive compound.

For example, the dye used in a humidity sensor using water as a test chemical substance has a hydrophilic group. The hydrophilic group may be any of a carboxylic acid group, a sulfonic acid group, a sulfuric acid group, a phosphoric acid group, a phosphonic acid group or salts thereof, a hydroxyl group, and the like, but particularly, a carboxylic acid group, a sulfonic acid group and the like. Is preferred. These hydrophilic groups may be present in the dye molecule in an amount of about 1 to 16, especially about 1 to 4.

The dye having such a hydrophilic group reversibly binds to water and reversibly releases water. The dye having such a hydrophilic group binds to moisture in the atmosphere in accordance with the amount of moisture, which changes the film properties of the dye film, particularly the thickness, and thereby changes the light reflectance.

Among these dyes, it is also preferable to use a phthalocyanine dye or a naphthalocyanine dye having a hydrophilic ionic group, because they are stable and have high reflectance, and two or more molecules of these dyes are contained in the dye film. The hydrophilic ionic groups may be bound to a cation having a valence of 2 or more, preferably a valence of 3 or more.

Of the central atoms of phthalocyanine dyes and naphthalocyanine dyes, V, Cu, and
Sn, Ni, Si and the like. Further, Si in which two other ligands are coordinated above and below the VO, phthalocyanine ring or naphthalocyanine ring is also preferable.

Further, as a preferable hydrophilic ionic group bonded to a divalent or higher cation, --SO ₃ (Fe
³⁺ ) _1/3 , -COO (Fe ³⁺ ) _1/3 , -SO ₂ (F
e ³⁺⁾ _1/3, and the like, the hydrophilic ionic group, it may be present at least one more in the dye molecule is preferably 2-8.

Such a dye is incorporated into the dye film in an amount of 2
There is a valence of 2 or more between the hydrophilic ionic groups of the molecule or more, preferably 3
Since it binds to a cation having a valency or more and preferably has a crosslinked structure through this cation, the water resistance of the sensor film is improved.

In the case of using a dye film that interacts with other test chemical substances, similarly, a dye having a group that interacts with the test chemical substance may be used.

Details of such a sensor are described in Japanese Patent Application No. 2-287568 by the present applicant.

When a film containing a chemically sensitive compound is laminated on the dye film and this laminated film is used as the sensor film, the dye contained in the dye film interacts with the chemical substance to be tested as described above. However, it may not necessarily interact with the test chemical substance.

Details of such a sensor are described in JP-A No. 2-193035, and the film thickness of the sensor film in this case is 500 to 1000000A, preferably 1000 to 50000A.

When a mixed film of a dye and a chemically sensitive compound is used as a sensor film, the above chemically sensitive compound may be appropriately mixed and used. In this case, the same dye as that used when the laminated film is used as the sensor film can be used.

Such a mixed film can be obtained by adding a chemically sensitive compound to the ultrafine particle dispersion liquid when the dye film is formed using the ultrafine particle dispersion liquid. At this time, the mixing ratio of the dye and the chemically sensitive compound is preferably 50/1 to 1/1 by weight ratio (dye / chemically sensitive compound).

Details of such a sensor are described in JP-A-2-169449, and the film thickness in this case may be the same as that of the dye film.

The material of the substrate in such a sensor is not particularly limited, but it is preferably substantially transparent. This is because it is possible to detect from the back surface side of the substrate.
Specifically, glass, hard vinyl chloride, polyethylene terephthalate (PET), polyolefin, polymethylmethacrylate (PMMA), acrylic resin, epoxy resin, polycarbonate resin, polysulfone resin,
Examples include various resins such as polyether sulfone, methylpentene polymer, and bisphenol A-terephthalic acid copolymer. The shape of such a substrate is not particularly limited, but is usually a plate or a film.

Further, the sensor film may be air-sandwiched with a water-permeable or air-permeable protective plate, or the protective plate may be provided on the film surface.

Further, a filter capable of selectively passing the test chemical substance may be provided on the membrane surface.

Further, after forming the dye film or the like on the substrate, it may be punched or cut into a desired size.
When this method is used, mass productivity is improved.

Further, a glass fiber may be used for the substrate and a dye film or the like may be formed on the end face thereof. Further, a plurality of these may be bundled and used. Alternatively, the end faces may be bunched and polished, and a dye film or the like may be provided on the end faces.

The chemical substance sensor of the present invention can measure the chemical substance to be tested in the range of ppb to 100% by bringing it into contact with the test fluid containing the chemical substance to be tested. ..

A preferred embodiment of the chemical substance sensor of the present invention is, for example, one having the structure shown in FIG.

As shown in FIG. 4, in the sensor 100, the sensor film 16 is formed on the transparent substrate 15, while the light emitting element 21 and the light receiving element 31 are provided on the back surface side of the transparent substrate 15. They are installed and these are casing 4
It is stored integrally in 0.

At this time, the sensor film 16 may be any of the dye film, laminated film and mixed film as described above.

The sensor film 16 is in contact with the test atmosphere.

Therefore, the light emitted from the light emitting element 21 enters from the back surface of the substrate 15, the specular reflectance of the light at this time is detected by the light receiving element 31 also provided on the back surface of the substrate 15, and the change in the reflectance causes The chemical substances will be detected and quantified.

In this case, it is preferable that the light emitting element 21 and the light receiving element 22 are installed close to each other, and the sensitivity is increased by measuring the reflection due to the specular reflection of 20 ° or less, particularly 5 ° or less, and the element Can be made compact.

The wavelength of the light emitted from the light emitting element 21 in the present invention is any wavelength in the visible to infrared range. The light emitting element 21 is not particularly limited, but is preferably a light emitting diode (LED), a laser diode (LD), or the like.

In the present invention, the irradiation of the light emitted from the light emitting element 21 to the sensor film is preferably intermittent. By performing the irradiation intermittently, the temperature rise of the sensor film can be suppressed. Therefore, the bond between the test chemical substance and the chemical substance-sensitive compound in the sensor film is less likely to be affected by heat, and the measurement accuracy in continuous measurement is remarkably improved.

The irradiation time for intermittent irradiation is not particularly limited, but it is preferable to set the irradiation time as short as possible within a measurable range, for example, 0.01 to 100 ms.
It is about ec.

The irradiation interval is not particularly limited, but in order to avoid the temperature rise of the sensor film, it is preferable to set the irradiation interval as long as possible within a range satisfying the required measurement interval. For example, when used as a normal humidity sensor,
The irradiation interval is about 0.1 to 10 msec.

In the present invention, there are no particular restrictions on the means for performing intermittent irradiation. For example, the emitted light may be directly controlled by intermittently energizing the light emitting element. In addition, intermittent irradiation can be performed by indirect control such that continuous emission light is applied to the sensor film via a chopper plate or the like. Further, in any of these methods, control is not limited to a pattern in which irradiation and resting thereof are alternately repeated, and control may be performed so as to change irradiation light intensity.

In the present invention, when intermittent irradiation is performed as described above, the detection circuit connected to the light receiving element includes an AC component detection circuit section, an amplification circuit section, an output level shift circuit section and a smoothing circuit section. Are sequentially provided, and the details thereof are described in Japanese Patent Application No. 2-218389 filed by the present applicant.

[0143]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 A dye-containing coating solution was prepared using the apparatus shown in FIG. First, preparation of an ultrafine particle dispersion liquid of a dye will be described.

Using cyclohexanone as a dispersion medium, phthalocyanine green (dye raw material: average particle size 10 μm) 10 wt.
The dispersion liquid containing 10% was made into ultrafine particles by Nanomizer [see FIG. 1: Nanomizer System manufactured by Nanomizer Co., Ltd.].
The liquid part was cooled with liquid nitrogen to prevent the temperature from rising and facilitate the pulverization of the dye. The pressure was set to 700 kg / cm ² and repeated 10 times.

At this time, the dye has a maximum particle diameter of 5000A and an average particle diameter of 2000A. The maximum particle size and the average particle size are values measured using an ultrafine particle size analyzer BI-90 (manufactured by Brookhaven Instruments), and the same applies hereinafter.

The solubility of the above dye in cyclohexanone is almost zero.

Next, the above dispersion was subjected to a centrifuge [Tomy Seiko KK: MRX-150]. The centrifugation conditions at this time were 10,000 rpm for 10 minutes, and the temperature was 20 ° C.
I did it in.

By such centrifugation, pigment particles having a particle size of more than 500 A were removed.

The maximum particle diameter of the pigment particles in the pigment-containing coating liquid thus prepared is 500A and the average particle diameter is 300A. It is considered that such a particle size is maintained even in the dye coating film.

A glass substrate (size 5) was prepared using the above coating solution.
cm × 5 cm: thickness 1.2 mm) was applied by spin coating and then dried at 70 ° C. for 1 hour. The dry film thickness at this time was 1000A. The spin coating is 100
The rotation speed was 0 rpm.

This dye coating film is designated as dye coating film No. 1.

Dye coating film No. 1 was obtained in the same manner as dye coating film No. 1 except that centrifugation was not performed.

The film physical properties of the above dye coating films No. 1 and No. 2 were evaluated.

The film physical properties were evaluated under the reflection condition when light of 700 nm was irradiated from the glass substrate.

The pigment coating No. 1 prepared by the method of the present invention had a reflectance of 23%, while the pigment coating No. 2 not subjected to centrifugal separation had a reflectance of 10%.

From these results, it is possible to obtain a film having excellent film properties in the present invention.

Example 2 A similar dye coating film was obtained except that the dye was changed to copper phthalocyanine in the dye coating film No. 1 of Example 1.
Using this as the recording layer 3, the substrate was made of a polycarbonate resin to prepare an optical recording disk as shown in FIG.
The polycarbonate resin substrate 2 has a diameter of 120 mm and a thickness of 1.2 mm, the groove 23 has a depth of 1600 A, a width of 0.45 μm, and a pitch of 1.6 μm, and was produced by injection molding. However, the thickness of the recording layer 3 is 220 in the groove.
It was set to 0A.

Then, an Au thin film having a thickness of 1500 A was formed on the recording layer 3 by sputtering to form a reflective layer 4. Further, a UV curable film type resin containing oligoester acrylate was applied and then UV cured. An optical recording disk No. 1 was prepared with a protective film 5 having a thickness of 5 μm.

When a CD signal was recorded on this optical recording disk No. 1 using a Yamaha PDS and then reproduced with a commercially available CD player, a sufficient reproduced signal was obtained.

The fluctuation range of the reflectance of the unrecorded portion of the recording layer was the same as in Example 1, and was about ± 1% of the reflectance. At this time, the reflectance was 68%.

In the optical recording disk No. 1, the same dye coating film was obtained except that the dye was changed to copper phthalocyanine in the dye coating film No. 2 of Example 1 in place of the above dye coating film. Optical recording disk No. 2 was prepared in the same manner except that this was used.

When this optical recording disk No. 2 was reproduced in the same manner as the optical recording disk No. 1, the reproduced signal contained a lot of spike noise. The fluctuation range of the reflectance of the unrecorded portion is about ± 5%, and the reflectance at this time is 65%.
%Met.

Example 3 A similar dye coating film was obtained except that the dye was changed to tetracarboxylic acid naphthalocyanine copper in the dye coating film No. 1 of Example 1, and this was used, as shown in FIG. We made a new sensor. However, the film thickness of the dye coating film is 7 in dry film thickness.
00A. The size of the glass substrate is 50m
m, width 50 mm, and thickness 1.2 mm.

Next, a coating film of acetylbutyl cellulose was laminated on this dye coating film to form a sensor film and a moisture sensitive film.

The coating film of acetyl butyl cellulose was formed by using a 2 wt% methanol solution of acetyl butyl cellulose and had a dry film thickness of 1000A.

This is referred to as sensor No. 1.

In the above, the glass substrate on which the laminated film was formed was adhered to one end surface of an optical fiber (ESCA CK-120 manufactured by Mitsubishi Rayon) having a length of 50 cm and a diameter of 3 mm with an acrylic adhesive. .. The other end surface of the optical fiber was pressed against a mirror-finished plate and heated to have a diameter of 4 mm, and at the same time smoothed. On the other end face, a light emitting diode (wavelength of emitted light 910
nm) and the phototransistor were bonded by an acrylic adhesive.

Using the above sensor, the light emitting diode was operated at a light emission time of 0.1 msec and a light emission interval of 0.9 msec to measure the relative humidity. The relationship between the relative humidity at this time and the output voltage of the sensor was investigated.

From these results, it was found that the concentration range of measurement was wide and the linearity was good. Also, the variation between products was small.

Further, this humidity sensor is operated at 60 ° C. and 90% R
It was used for 1 month under H condition.

When the output voltage at 55% RH was examined one month later, it was found that the output voltage was only 5% down.

In Sensor No. 1, except that the dye is changed to copper tetracarboxylic acid naphthalocyanine copper in Dye Coating No. 2 of Example 1, a dye coating is obtained in the same manner as above, except that this is used. Then, when the relationship between the relative humidity and the output voltage of the sensor was examined, the variation between the products was larger than that of the sensor No.1. In addition, the voltage after one month was 5% down.

[0174]

According to the present invention, the pigment particles in the ultrafine particle dispersion liquid of the pigment can be quickly made to have a predetermined particle size. As a result, good film physical properties can be obtained, and the characteristics as an optical disk or a sensor become good.

[Brief description of drawings]

FIG. 1 is an exploded perspective view for explaining a configuration of a nanomizer used in the present invention.

FIG. 2 is a schematic configuration diagram showing a configuration example of an apparatus used in the present invention.

FIG. 3 is a partial sectional view showing an optical recording disk to which the present invention is applied.

FIG. 4 is a cross-sectional view showing one structural example of a chemical substance sensor to which the present invention is applied.

[Explanation of symbols]

 1 Optical Recording Disk 2, 15 Substrate 3 Recording Layer 10 Nanomizer 15 Sensor Film 100 Sensor 30 Centrifuge 50 Spin Coat Part

Claims (6)

[Claims] 1. A method for preparing a dye-containing coating liquid used for forming a dye coating film, wherein a dye is dispersed in ultrafine particles to obtain a dispersion, and then this dispersion is centrifuged to obtain a large particle size. A method for preparing a dye-containing coating liquid, which comprises removing dye particles. 2. The method for preparing a dye-containing coating liquid according to claim 1, wherein at least dye particles having a particle size larger than the film thickness of the dye coating film are removed. 3. The method for preparing a dye-containing coating liquid according to claim 1, wherein the dispersion of the fine particles of the dye is performed by causing a dispersion liquid containing a dye material pressurized under a high pressure to collide with each other. 4. The method according to claim 1, which is used for spin coating.
5. A method for preparing a dye-containing coating liquid according to any one of 1. 5. The method for preparing a dye-containing coating liquid according to claim 1, which is used for forming a dye coating film which is a recording layer of an optical disk. 6. The dye-containing coating liquid according to claim 1, which is used for forming a dye coating film of a chemical substance sensor configured such that the light reflectance of the dye coating film is changed depending on a chemical substance to be tested. Preparation method of.