JPS62204202A - Polarizing film - Google Patents

Abstract

PURPOSE:To obtain the titled film having heat-resisting property, moisture- resisting property and mechanical strength and capable of displaying a highly orientation property by dying and orientating a dischroic coloring matter and by composing of a polyester film having a liquid crystal property due to a specific coloring matter. CONSTITUTION:The titled film is composed of the polyester film having the liquid crystal property which has >=0.7 orientation factor (Fdye) due to the coloring matter by dyeing and orientating the dichroic coloring matter. The polyester resin is preferably the liquid crystal polyester resin composed of the copolymerized polyester comprising polyethlene terephthalete component (A) and parahydroxy benzoic acid component or para acetoxy benxoic acid component (B) and having the component or para acetoxy benzoic acid component (B) and having the composition ratio of (A) and (B) of (40:60)-(5: 95), by mole ratio. The transparent film is produced by melting the polyester resin under shearing and drafting to form a film. Thus, the titled film having the mechanical property, the heat-resisting, the moisture-resisting and the weather-proofing properties and having a less tendency for generating deterioration of polarizing property under high temp. an humidity is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention resides in a polarizing film. Specifically, it relates to a polarizing film in which a dichroic dye is dyed and oriented on an iA polyester film, which has excellent parallel light transmittance, and which can be easily produced by melt-produced MK.

[Conventional technology and its problems]

Conventional polarizing films include polyvinyl alcohol (
It is well known that PV'A) type films are dyed with iodine or dichroic dyes.

However, although these polarizing films have excellent polarizing performance, they have drawbacks in heat resistance, moisture resistance, etc., and in order to improve these problems, they are laminated with a cellulose acetate film or the like. However, even this does not provide sufficient moisture resistance depending on the application.

``'' PVA As a polarizing film based on hydrophobic polymers other than A-based, halogenated vinyl polymers such as polyvinyl chloride (PVO) and polyvinylidene chloride (PVDO) are treated with dehydrohalogenation to form polyenes. Polarizing films with structured structures are also being considered, but they are still the mainstream polarizing film because they have problems with heat resistance, stability against light and oxygen, and it is not possible to freely select the hue. It has not yet reached the point where it accounts for the majority of the total.

Furthermore, for example, JP-A-Sho s7-gtitt09, JP-A-Sho 3T
142/, etc., discloses polyamide-based and polyester-based polarizing films. Polyamide-dye-based and polyester-dye-based polarizing films are heat resistant,
Although its moisture resistance and mechanical strength are superior to P'7A-iodine polarizing film and PTA-dichroic dye polarizing film, it is still at the stage of practical application because its polarizing performance is inferior to that of P'7A-iodine polarizing film. I haven't reached that point yet.

[Means for solving problems]

The inventors of the present invention have conducted intensive studies to resolve the above-mentioned conventional problems, and have found that by using a combination of a specific resin and a specific dye, a high level of alignment performance can be achieved with the simple method of melt film formation. The present invention was completed based on the discovery that a film with high polarization performance can be obtained.

That is, the gist of the present invention is that the dichroic dye is dyed and oriented, and that the dye has an orientation coefficient 'fF dye value of 0.
The present invention relates to a polarizing film made of a liquid crystalline polyester film having a molecular weight of 7 or more.

The polyester resin for obtaining the polarizing film of the present invention includes a polyethylene terephthalate component (A) and a para-hydroxybenzoic acid component or a para-acetoxybenzoic acid component (B).
) and the composition ratio of (A) to (B) is tio to 60 to j to ? It is preferable that the liquid crystalline polyester resin is between j. A transparent film can be obtained from this polyester resin by melt-forming it under shearing and drafting.

The high orientation of polymer compounds (liquid crystalline polymers) that exhibit liquid crystallinity in a solution or molten state is known as a technique for processing them into highly elastic fibers and films by solution, melt spinning, or film forming. However, due to the non-uniformity of the liquid crystal polymer and the rotation of the liquid crystal phase, the fibers and films obtained are opaque, making it impossible to apply them to optical applications such as polarizing films. .

As described above, it is extremely revolutionary that the present invention imparts transparency to a liquid crystalline polyester film, and utilizes the film's high orientation to dye and orient dichroic dyes to create a polarizing film. It's a matter of fact.

Here, the F clie value will be explained. F dye is calculated using the following formula (1).

FcLyθ=(D-/)/CD+ko] 0...
(1) Here, D is the absorption-color ratio of the dichroic dye-containing film and is based on the following formula (2).

D=Log (work@/work m)/Log (work 0/work I)...
...(2) However, the transmittance of an undyed film under the same film forming conditions is calculated. The transmittance values when the polarization plane of the incident light beam and the orientation axis are perpendicular and parallel to each other are II and 1 violet, respectively. F
The dye value represents the degree of orientation of dichroic dye, and F cly
A high e value indicates that the polarizing performance of the polarizing film is high.

The material of the liquid crystalline polyester film used in the present invention is a polyethylene terephthalate component (A) and a para-hydroxybenzoic acid component or a paraacetoxybenzoic acid component (B) in a molar ratio of (A) to (B) and a ratio of θ to 60 to 5 pairs? This is a polyester resin that is copolymerized so that it is between .

The composition ratio of (A) to (B) is molar ratio, and it is 60 to 60 (
A) When the number of components increases, the anisotropic phase becomes non-uniform.
Furthermore, as the anisotropic phase is no longer observed, orientation due to shearing does not proceed even if such a resin is melted into a film, so F
The dye value does not improve and a transparent film cannot be obtained.

Also, the composition ratio of (A) to (B) is molar and j to 9S (
If the amount of component B) increases, the meltability of the resin will be lost and melt film formation will not be possible, which is not preferable. As component (B), it is preferable to use a parahydroxybenzoic acid component.

The polymerization method of the polyester resin is disclosed in JP-A-60-/IAj
Similar to core, K can be produced by contacting and reacting polyethylene terephthalate or polyethylene terephthalate oligomer with parahydroxybenzoic acid, followed by acetylation and polymerization, and further deacetic acid. Furthermore, it can be produced by reacting polyethylene terephthalate or the like with acetoxybenzoic acid and then polymerizing the same, according to Japanese Patent Publication No. 34/1978. In addition, as long as the composition ratio of (A) to (E) is maintained within the above range in the resin composition, hydroquinone, etc. (A)
A third component having copolymerizability with component (B) may be copolymerized.

A method for manufacturing a polarizing film from the above-mentioned liquid crystalline polyester resin involves mixing the resin with a dichroic dye and then melting the film.

The dichroic dye used in the present invention is selected from direct dyes, disperse dyes, acid dyes, etc., which have dichroism in their molecular structure, and has the following structural formula, for example. It is something.

−Two Hz 〇　　〇H OH O0H OdJOOH OMH.

ON& 0 1H.

ON & ON & OH OH As the dichroic dye, one of the above-mentioned ones or a mixture of several kinds may be used.

The method of use is, for example, by mixing it with a polyester resin by methods such as triblending, melt blending, and solvent mixing.

The amount of the dichroic dye to be mixed is preferably selected from the range of o, oi, more than 10% by weight, but less than 10% by weight.

The characteristics of the liquid crystalline polyester resin of the present invention are that it exhibits high alignment performance with only a very simple process of melt film formation, and that polarizing films can be easily manufactured without blending dichroic dyes during film formation. be. This is a major advantage in terms of production costs compared to the case of ordinary polymers, which require some kind of stretching treatment after film formation in order to obtain an oriented film. The method for producing the film is novel and extruded under suitable shear and draft conditions.

When the liquid crystalline polyester resin of the present invention is formed into a film under shearing, the rigidity of the resin segments causes the segments to be oriented in the flow direction, and as a result, transparency is imparted to the film. Therefore, it is desirable that the shear rate during film formation be higher, and the general film forming conditions (shear rate; several tens of 5 ec-'~
Although sufficient orientation and transparency can be obtained even with a shear rate of several hundred 5 ea-', the orientation and transparency are further improved by forming the film at a high shear rate of /0005 ea-' or higher. Further, the film thickness of the produced film is usually set to less than 100 μm in order to impart transparency, and the draft ratio may be determined in accordance with this.

The film forming temperature is such that the liquid crystalline polyester resin of the present invention is liquid crystalline (
Any temperature range is sufficient as long as it exhibits anisotropy during melting.
The temperature range is 0°C to UOO°C.

Cooling during film formation may be performed using a normal cooling roll, but in the case of high-shear molding, high-speed molding increases synergy, so it is preferable to use a water-cooling system with a cooling water tank provided directly below the die. This suppresses the orientation relaxation of the film-forming resin due to rapid cooling, which has a positive effect on orientation and transparency.

The polarizing film obtained as described above is completely conventional in that it is made of liquid crystalline polyester resin and has transparency, and the resin film itself is excellent. The polarizing film made of the resin has excellent mechanical properties, heat resistance, water resistance, and weather resistance, and its polarizing performance does not deteriorate under conditions of high temperature and high humidity.

Depending on the purpose of use, the polarizing film may be used in a protected state by lamination or coextrusion with other plastics.

〔Example〕

The present invention will be described below with reference to Examples, but the present invention is not limited to the following Examples unless the gist of the invention is exceeded.

Prior to the examples, methods for measuring the following items will be described.

Parallel light transmittance...integrating sphere type light transmittance measuring device Digital turbidity meter NDH-coOD (manufactured by Nippon Denshoku Kogyo Co., Ltd.) According to J Eng 8117/da.

P dye value...Using a spectrophotometer - S type (newly manufactured by Hitachi), the incident light is transmitted when the plane of polarization of the ↓V- line and the orientation axis are perpendicular or parallel! , 1 was measured in the visible region, and the orientation coefficient (Pays) was calculated based on the following formula.

paye=CD-/)/(IH-co) (However, D is the absorption dichroic ratio, D=L Og (Work V Work U) Luog (Work Finish Work ■) Work. Same stretching processing conditions. Example 1 Polyethylene terephthalate oligomer (ηtnh O
0/OeLll/l/)/00 parts were mixed with 1 part of parahydroxybenzoic acid and 0.13 parts of stannous acetate and stirred at λO°C for 1 hour under a nitrogen stream, and then the temperature was reduced to taOo.
After the CK had decreased, 66 parts of acetic anhydride was added and stirred for 1 hour and 30 minutes.

To prevent acetic acid from accumulating, raise the temperature to S°C and add 0.0% zinc acetate dihydrate. ．． After adding 1.7 parts 0. The pressure was gradually reduced to Jtorr and the mixture was stirred for 6 hours to complete the polymerization.

The composition of the obtained polymer was 10 moles of polyethylene terephthalate component and 10 moles of para-hydroxybenzoic acid component, and it was confirmed that it exhibited anisotropy when melted under a polarizing microscope equipped with a heat stage. .

This liquid crystalline polyester resin is used in a T-die (die width l).
A film was formed using a 30-inch extruder equipped with a lip clearance of 0-m). The film forming conditions at this time were: temperature s°C, shear rate 2900 sec-', draft ratio /j
This was done using a water cooling system using a cooling water tank with the air gapper turned on. The parallel light transmittance of the thus obtained undyed film was measured and shown in Table 7.

Next, a dye represented by the following formula was mixed with the above polyester resin in a Henschel mixer at a ratio of o and jt amount percent, and then T-die film formation was performed in the same manner as above to produce a blue polarizing film. F of the obtained polarizing film
'dye values were measured and shown in Table 1.

However, the Fdye value was the average value of each value at a wavelength of 660 and 4g0.700 nm.

Example Using the same liquid crystalline polyester resin and dye as in Example 1, T-die (die width l 0 III; lip clearance 0.3 positive), shear rate jOo day ec-' draft ratio co 3
Film formation was performed in exactly the same manner as in Example 1 except for the following. Parallel light transmittance of the obtained undyed film and polarizing film? (17e values are shown in Table 1.

Example 3 Polyethylene tele-7 tallate olicomer (ηinh O
, / 0 (1] / 11 ) / 00 parts were stirred with 16j parts of rose hydroxybenzoic acid and 0.09 parts of stannous acetate at 0°C under a nitrogen stream for 1 hour, then warmed and heated for 1 hour 30
The mixture was stirred for a minute. After raising the temperature to 273°C while accumulating acetic acid and adding o, it, parts of zinc acetate dihydrate, 0.3
The pressure was gradually reduced to torr and the mixture was stirred for 6 hours to complete the polymerization.

The composition of the obtained polymer was as follows: polyethylene terephthalate component: JO mole percent, parahydroxybenzoic acid component: 7 mole percent, and it was confirmed that it exhibited melting singularity under a polarizing microscope equipped with a Siheat stage, and that it was liquid crystalline. did.

This liquid crystalline polyester resin T-die (die width l)
;Lip clearance 0. / 30m1 with
A film was formed using an extruder.

The film forming conditions at this time were a temperature of 27! ;℃, shear rate/00
The test was carried out at 0 sec""' using a draft ratio saw using a cooling water tank and using the water quality method with the air gapper ON. The parallel light transmittance of the thus obtained undyed film was measured and shown in Table 7.

Next, the same dye as in Example 1 was mixed into the above polyester resin, and then T-die film formation was performed in the same manner as above to obtain a polarizing film.

The Fdye value of this film was measured and shown in Table/.

Comparative Example 1 Polyethylene terephthalate oligomer (ηinh O
, I Odll/11)/00 parts with one part of rose hydroxybenzoic acid and 0006 parts of seventh tin acetate at qo℃
Stir for 1 hour under a nitrogen stream, then reduce the temperature to tSO''CI
After C was lowered, 66.3 parts of acetic anhydride was added and stirred for 1 hour and 30 minutes.

The temperature was raised to S°C without allowing acetic acid to accumulate, and 0.1 part of zinc acetate dihydrate was added. Gradually reduce the pressure to J torr and stir for 6 hours to complete polymerization.

The composition of the obtained polymer was that the polyethylene terephthalate component was so mole percent, and the parahydrococonut benzoic acid component was jO mole percent sb, and this resin also exhibited melt anisotropy.

This liquid crystalline polyester resin was formed into a film in the same manner as in Example 1 to obtain an undyed film and a blue polarizing film.

The parallel light transmittance and Fdye value of the film were measured and shown in Table 1.

Table / * Composition ratio; polyethylene terephthalate component: para-hydroxybenzoic acid component shown in molar percent ratio.

As is clear from Table I, the film according to the present invention (Example/Sco, 3) has better transparency than the film of Comparative Example 1), has a higher IF dye value, and has a significantly greater polarizing ability. .

〔Effect of the invention〕

According to the present invention, a film having excellent transparency, polarization performance, etc. can be obtained by a simple method, and is very effective in practice.

Applicant Mitsubishi Chemical Industries, Ltd. Agent Patent Attorney Hase - (1 other person) 12-2 Procedural Amendment (spontaneous) 2 Name of the invention Polarizing film 3 Person making the amendment Applicant (JF&) Mitsubishi Chemical Industries, Ltd. Co., Ltd. 4 Agent〒i
o.

5 Subject of amendment Detailed explanation of the invention in the specification column 6 Contents of amendment (1) Line 7 of the first page of the specification to line 1 of the first page ``Used in the present invention...'' It is preferable that...
Correct the statement in the attached document.

Attachment The dichroic dye used in the present invention is selected from direct dyes, disperse dyes, acid dyes, etc., which have dichroism in their molecular structure, and has the following structural formula. It is something that you have.

OOH OOH 0H Number one - −　Ma　− Ri eyes 1! Above i8 li.

As the dichroic dye, the above-mentioned ones may be used alone or as a mixture of several types.

The method of use is, for example, by mixing it with a polyester resin by methods such as triblending, melt blending, and solvent mixing.

The amount of the dichroic dye to be mixed is preferably selected from the range o, oi % by weight or more and less than 10% by weight.

1l- =17-

Claims (3)

[Claims] (1) A polarizing film made of a liquid crystalline polyester film in which a dichroic dye is dyed and oriented and has an orientation coefficient Fdye value of 0.7 or more. (2) In the liquid crystalline polyester film, the parallel light transmittance of the film is 70% or more when the dichroic dye is not dyed and oriented. polarizing film. (3) The liquid crystalline polyester film is a copolymerized polyester consisting of a polyethylene terephthalate component (A) and a parahydroxybenzoic acid component (B), and (A) and (B)
The polarizing film according to claim 2, characterized in that the polarizing film is made of a liquid crystalline polyester resin having a composition ratio of 40:60 to 5:95 in terms of mole %.