JPS62269901A - Polarizing film using perylene dye - Google Patents

Abstract

PURPOSE:To obtain a high degree of polarization and substantial dimensional accuracy by orienting a specific perylene dye and incorporating the same into a hydrophobic resin. CONSTITUTION:The perylene dye expressed by formula (I) [in formula (I), R<1> and R<2> are a hydrogen atom, halogen atom, methyl group or methoxy group, R<3> and R<3>' denote the same formulas (a)-(d) (in the formulas (a)-(d), R<4> is a hydrogen atom, alkyl group, cycloalkyl group or aryl group, R<5> is a hydrogen atom, alkyl group, alkoxy group, cycloalkyl group, aryl group or halogen group, Y denotes an oxygen atom or sulfur atom, m is 1 or 2 integer, and a ring may be formed together with a carbon atom to be bonded by the same if m is 2), n and n' respectively denote 1 or 2 integer] is oriented and incorporated into the hydrophobic resin. The polarizing film which has the high polarization degree and has the dimensional stability and the stable polarization degree is thus obtd.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Industrial Field of Application] This invention relates to a polarizing film using a specific perylene dye.

[Background of the Invention] The polarizing film most commonly used today uses polyvinyl alcohol-based resin as the film base material, which is coated with an iodine compound and/or a dye such as an acid dye or a direct dye having a selected structure. It has polarization properties using a colored substance. Although this type of polarizing film exhibits excellent polarizing ability, its durability is insufficient, and it is usually made to last by covering both sides of the film with a film-like material (protective film) that is moisture resistant and transparent on at least one side. gender is preserved. That is, measures have been taken to obtain practical durability by protecting the defects of the internal polarizing film (layer), which is extremely poor in durability due to its woody nature, with the protective layer on both sides.

In recent years, with the expansion of the use of liquid crystal display elements in automobiles, computers, industrial equipment, etc., it is necessary to improve the durability of the polarizing film used as an element, especially in terms of moisture resistance, weather resistance, and heat resistance. It is strongly requested. For this reason, a polarizing film using a hydrophobic resin as a base material has been proposed as an improvement means, and as a known technique,
No. 84409 and No. 58-1i80 by the present inventors
Examples include No. 08 and No. 60-125804. However, although such polarizing films have sufficient durability, the reality is that they are not necessarily satisfactory in terms of polarizing properties.

[Problems to be solved by the invention] Immediately after manufacturing, this type of polarizing film is
In some cases, it has polarizing performance comparable to that of other polarizing films, but when used for a long time, especially when used in a heated state, the degree of polarization decreases significantly, which poses a practical problem. The main reason for this is that the dyes used as polarizers are dichroic dyes developed primarily for liquid crystals, and are generally structurally selected to dissolve in liquid crystal materials in as high a concentration as possible. . However, it is thought that this is because such dye molecules easily move in a hydrophobic resin film base material such as polyethylene terephthalate due to 8N force, especially when heated, and disturb their own arrangement. In addition, in the manufacturing process of this type of polarizing film, a heat treatment step following the stretching step is usually used to prevent shrinkage of the film and obtain dimensional stability. When using dyes that have extremely high solubility in hydrophobic base resins, such as dichroic dyes for liquid crystals, the degree of polarization may be quite high immediately after the stretching process, but during the heat treatment process After this process, the degree of polarization significantly decreases, which is an inconvenience.

Therefore, in this type of polarizing film, if you want to obtain a polarizing film with a high degree of polarization, after the stretching process,
Since it is not possible to perform heat treatment to a sufficient degree for heat fixing, it is not possible to obtain a material with sufficient dimensional stability and a stable degree of polarization. If so, a sufficient heat treatment would have to be carried out after the stretching treatment, making it impossible to obtain a material with a high degree of polarization.

[Object of the Invention] An object of the present invention is to provide a polarizing film in which a hydrophobic resin is used as a film base material, a perylene dye is blended therein as a red component, and the polarizing film is wound together.

[Means for solving the problem] As a result of various studies to solve the problem, we found that the most important requirements for the dye used to solve the above problem in polarizing films using hydrophobic resin as the film base material are as follows: The inventors have discovered that the most important characteristic is to have high dichroism, and that they must also have certain pigment suitability, and have arrived at the present invention.

That is, the present invention that achieves the above object includes, in a hydrophobic resin,
General formula (I) [In formula (I), R1 and R2 may be the same or different and are each a hydrogen atom, a halogen atom, a methyl group or a methoxy group, and R3 and R3' may be the same or different, Formulas (a) to (d)-C0NH-R', respectively
(a) -C~R' (b) (In formulas (a) to (d), R4 is a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group, and R@
is a hydrogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, an aryl group, or a halogen atom, Y is an oxygen atom or a sulfur atom, m is an integer of 1 or 2, and when m is 2, they are may form a ring together with the bonded carbon atoms, and n and n' each represent an integer of 1 or 2. ] The perylene dye is oriented and contained. It is a polarizing film.

The perylene dye represented by the general formula (I) is used to color a hydrophobic resin to obtain the polarizing film of the present invention, and the polarizing film of the present invention has particularly good durability and polarizing performance. .

Furthermore, among the dyes represented by general formula (I), n and n''=
The dye No. 2 is particularly suitable as a dye for polarizing films.

The present invention will be explained in detail below.

Specific examples of the substituent represented by R4 in the general formula (I) include H;-C1li, -C211s, -(
C) IJ*CH3゜-CIl(CIl)*, -(C
Ht)scdays, -CII*C)I(CH,)*,
<)I(CH:+)C2J, -C(Clh)z, -
(CHa)ncHz, -(CHt)scHz.

−((:1la)sC)I+, −(CHa)tcHs
, an alkyl group such as -(CHt)acHx, 4*H1
40CHy, -CzH40C2Hs, -CtH40(
CH2)sC)I2゜-CtH40((:L)YCH,
Alkoxyalkyl group such as: below margin F・(XΣCON+18CH,.

(XyCONH&(CHt)acH3,u N=NC2
Examples include aryl groups such as.

etc. can be mentioned.

etc. can be mentioned.

The dye of general formula (I) is a perylenetetracarboxylic anhydride represented by formula (II) and general formula (m) I [in formula (m), R1, R'', R and n are A method of boiling aromatic amines represented by [the same as defined above] in an inert solvent such as nitrobenzene, or perylenetetracarboxylic anhydride represented by general formula (I), etc. After boiling moles of aromatic amines represented by the general formula (m) in an inert solvent such as nitrobenzene, the general formula (m)'R' [ill, R2, in the formula (m)'R3'' and n' have the same meanings as defined above. ] It can be easily synthesized by adding aromatic amines represented by and boiling.

These perylene dyes of the present invention have dichroism suitable for polarizing films and at the same time have physical properties of being substantially insoluble in water, organic solvents and liquid crystals.

Here, "substantially insoluble" means that at room temperature, that is, about 25° C., the dichroic dye is less than or equal to 0%, preferably 0% or less, in water, organic solvent, and liquid crystal, respectively.
．． It must have a solubility of 0.01% by weight or less. In addition, organic solvents here include acetone, methyl alcohol,
Ethyl alcohol, chloroform, benzene, toluene, xylene, nitrobenzene, chlorobenzene, 0-dichlorobenzene, N,N-dimethylformamide, N-
It is an easily available inert organic solvent with a boiling point of 250°C or less, such as methyl-2-pyrrolidone or ethyl acetate.

Furthermore, liquid crystals include liquid crystals having a nematic phase or smectic phase that are fluid at room temperature, such as Schiff base liquid crystals, biphenyl liquid crystals, phenylcyclohexane liquid crystals, ester liquid crystals, pyrimidine liquid crystals, and mixtures thereof. .

As mentioned above, an important characteristic of the dichroic dye used in the present invention is that it is substantially insoluble in organic solvents and liquid crystals. This indicates that it has a certain pigment suitability.

Such dyes are suitable for use in polarizing films based on hydrophobic resins, and it is important to select dichroic dyes for such polarizing films because they are soluble in liquid crystals and have excellent dichroism. This means that it is impossible to determine whether That is, the means for determining whether the dichroic dye of the present invention has excellent dichroism suitable for use in a polarizing film has not necessarily been clear.

The inventors of the present invention, Nagisa et al., determined the polarizing film of the present invention by measuring the dichroism of the dye in polyethylene terephthalate, which is a representative example of a hydrophobic resin, as an effective means for evaluating the dichroism of the dye. This method was used to determine the suitability of dyes for use in The method involves uniformly mixing an appropriate amount of dye into a pellet of polyethylene terephthalate having an intrinsic viscosity of 0.6 to 0.75, forming a film by melting it, and then applying it at least vertically at a temperature near or above the glass transition temperature. This is a method of measuring the dichroic ratio of a dye at the maximum absorption wavelength within the visible light region using a film obtained by stretching the free width three times or more as a sample.

The perylene dye used in the present invention has a dichroic ratio of 7 or more as measured by the above method, and is a polarizing film made of an aromatic polyester resin such as polyethylene terephthalate and other hydrophobic resins as a film base. Suitable as a coloring agent.

Conventionally, according to the method S and criteria as described above.

It is now possible to easily select dyes for which it has been difficult to determine whether or not they have sufficiently high dichroism for use in polarizing films.

In the production of the polarizing film of the present invention, the dye used can be used in its crude form, but it is preferably purified using recrystallization or other purification means, and it is also pulverized to a size of several microns or less. It is preferable to use it as

The polarizing film of the present invention contains at least one of the above dyes, and several types can be selected and mixed for use in order to obtain a desired hue, and especially to obtain a neutral gray polarizing film. Furthermore, it may contain dichroic dyes other than those of the present invention, in some cases, additives such as non-dichroic dyes or ultraviolet absorbers, and other substances.

The hydrophobic resin used in the polarizing film of the present invention is not particularly limited in molecular structure as long as it is an organic polymer compound having a linear structure that does not contain a hydrophilic group, but preferably has thermoplasticity.

Specifically, halogenated vinyl polymer systems, acrylic systems,
Examples include polyolefin-based, polyamide-based, polyimide-based, polyester-based, polycarbonate-based and polyethersulfone-based resins. Among them, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene bis-α, β-(2-chlorophenoxy)ethane-4,4'-dicarboxylate, etc., which have particularly excellent heat resistance, moisture resistance, and transparency, are used. A resin composition containing at least 80% by weight of an aromatic polyester resin component is preferred.

The amount of the dye to be used relative to the base resin, which is a hydrophobic resin as described above, is determined by taking into account the coloring ability of the dye and the desired thickness of the polarizing film, but preferably one polarizing film to be obtained. Visible light transmittance per unit is 30-60
For example, if the thickness of the polarizing film is 30 to 200 mm, the amount of the dye to the base resin is in the range of 0.01 to 10% by weight.

In order to produce the polarizing film of the present invention, the base resin and at least one selected from the dyes of the present invention described above are melted and colored together with other dyes mixed if necessary, and then formed into a film or sheet. 1st then 50-150
After stretching 3 to 10 times in the longitudinal or transverse direction at a temperature of °C,
It can be produced by heat treatment at 100 to 230°C for 1 second to 30 minutes.

Note that the stretching in only one direction is sufficient.

If necessary, the mechanical strength of the film can be improved by stretching the film approximately 1.1 to 2 times in the direction perpendicular to the main stretching direction.

The polarizing film manufactured in this way can be processed into various forms of films and sheets depending on the purpose and put to practical use. That is, a) the film produced by the above method as it is, b) a protective film with excellent optical transparency and mechanical strength on one or both sides, such as a protective film made of colored or uncolored glass or synthetic resin. Polarizing sheet or film with a membrane (layer); C) Polarizing sheet or film with an adhesive coated on one or both sides for ease of application to commonly used liquid crystal displays, window glasses, glasses, etc. Examples include d) a polarizing film in which a transparent conductive film such as an indium-tin oxide is added to the surface of the polarizing film by a well-known method such as vapor deposition, sputtering, or coating. These can also be used as cell forming materials for liquid crystal display elements.

[Examples] Hereinafter, representative examples of the dye of the present invention and a polarizing film using the dye will be specifically described with reference to Examples.

Note that the degree of polarization in Examples is a value measured by the following method. In other words, the light transmittance (To) at the maximum absorption wavelength in the visible region measured by stacking two polarizing films so that their stretching directions are parallel and placing them in the optical path of a spectrophotometer, and The degree of polarization (V) was calculated using the following formula from the light transmittance (t) at the same wavelength, which was measured by overlapping them so that they were perpendicular to each other.

Examples 1 to 14 Examples of the use of perylene dyes used in the polarizing film of the present invention are the dichroic ratio at the maximum absorption wavelength in polyethylene terephthalate and the degree of polarization at the maximum absorption wavelength of the polarizing film (single transmittance 40%) and hue in Table 1 below.
Shown below.

(Note) This polarizing film base resin is unmarked: Polyethylene terephthalate 1): Blend of 80% by weight polyethylene terephthalate and 820% by weight polybutylene terephthalate 2) ・Blend of 80% by weight polyethylene terephthalate and 20% by weight polyethylene naphthalate Blend 3): This is the degree of polarization of the polarizing film which is nylon 6.

Claims (1)

[Claims] In the hydrophobic resin, there are general formula (I) ▲mathematical formula, chemical formula, table, etc.▼ [In formula (I), R^1 and R^2 may be the same or different, and each A hydrogen atom, a halogen atom, a methyl group or a methoxy group, R^3 and R^3' may be the same or different, and each has a formula (a) to (d) -CO
NH・R^4(a) -CO_2・R^4(b) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(c) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(d) (Formula (a) ~ ( In d), R^4 is a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group;
^5 is a hydrogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, an aryl group, or a halogen atom, Y is an oxygen atom or a sulfur atom, m is an integer of 1 or 2, and when m is 2, Together with the carbon atoms to which they are attached, they may form a ring. ), and n and n' each represent an integer of 1 or 2. ] A polarizing film characterized by containing a perylene dye represented by the following in an oriented manner.