JPH03122159A - Film composition - Google Patents

Abstract

PURPOSE:To provide a colorless, transparent and optically isotropic film composition containing a specific aromatic polyester resin and an antioxidant. CONSTITUTION:A film composition comprises an aromatic polyester resin having structural units of formula I (X is 1-10C divalent hydrocarbon, O, S, SO2 or CO; R and R' are 1-20C alkyl, allyl, aralkyl, alkoxy, halogen, etc.; p+q=0-8; m and n are 0 or 1) as a main component and structural units of formula II (R1 to R4 are 1-4C alkyl, alkoxy, phenyl or halogen) as a part or all of the units of formula I and an antioxidant (preferably a phenolic compound) having a melting point of >=100 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a film composition, and more particularly to a film composition whose main component is an aromatic polyester resin and which is optically isotropic. .

[Conventional technology]

Conventionally, aromatic polyester resin films with optical isotropy have been widely used in liquid crystal displays and electroluminescent displays, which are widely used in watches, televisions, IC cards, word processing computers, instrument panels, and various display panels. In recent years, it has been particularly used as a surface protection film for parts and polarizing plates, a transparent conductive film, and a surface protection film for original floppy disks, optical cards, etc.

However, due to their optical properties, these aromatic polyester resins are often manufactured mainly by solvent casting, and in order to dry the small amount of solvent remaining in the film, they are heated at 200 to 300°. Exposure to a temperature atmosphere of C for a long time.

Further, when imparting conductivity to the film, the film is exposed to high temperatures of 150° C., for example, in the case of sputtering processing, and at least 150° C. when used as an FPC.

In the case of the above-mentioned film processing, particularly in the case of processing for optical applications, the film often yellows and becomes unusable for practical use.

Various countermeasures have been proposed, but none of them have yielded effective results and have not yet been put to practical use.

Countermeasures that have been proposed so far include, for example, JP-A-50-83
No. 446, JP-A-51-102042, % JP-A-52-
No. 98049, JP-A No. 58-210959, JP-A-Sho 5
No. 9-33355 and JP-A-60-173043, etc., use triazole derivatives, phosphite compounds, diphenylamine derivatives, phosphite compounds and fatty acid amides and/or epoxy compounds, and phosphite compounds and organic compounds as anti-yellowing agents. Additives are added to the film in combination with metal carboxylates, etc., but the use of these additives is important for optical applications, especially applications that require optical isotropy, to improve transparency and prevent yellowing. The effect is not sufficient, and even in the secondary processing of the film, these additives may blow out on the film surface, and as a result,
For example, problems have arisen in which transparency and even electrical properties are severely impaired.

In this way, the measures to prevent yellowing that have been proposed so far lack effectiveness and have not yet been widely adopted in practice.
The industry has requested the development of a highly practical yellowing prevention measure.

[Problem to be solved by the invention]

The object of the present invention is to solve the aforementioned problems of the prior art and to provide a completely new film composition, hitherto unknown.

[Means for solving problems]

The present invention was made to solve the above-mentioned problems, and provides a film composition characterized by containing at least an aromatic polyester resin and an antioxidant.

In the present invention, "optical isotropy" means that when light passes through the film of the present invention, there is no substantial change in the optical properties I, and the optical properties are as follows:
For example, n! It is determined by its refractive properties.

Here, "refraction" is a phenomenon in which light incident on a substance is split into two light waves with vibration directions perpendicular to each other.

When light of wavelength λ is incident on a sheet with thickness d and birefringence n2-n, if the wavelength of the faster light in the sheet is λ0 and the wavelength of the slower light is λ2, then the slower light exits the sheet. The amount by which light lags behind the earlier light is called retardage 1.
It is expressed by the following formula, and this degree is taken as the birefringence value.

R-λ(d/λ2-d/λ,) = d(λ/λ2-λ/λ□) = d(n2-n) This birefringence value can be calculated using, for example, a polarizing microscope (
It can be measured by the Senarmont compensator method using OP'rIPI (OT-POL type), and in the present invention, the birefringence value is 50 nm or less, preferably 2.
It is 0 nm or less, more preferably 10 nm or less.

When a film with birefringence of 50 nm or more is used, for example, in a liquid crystal cell installed between two polarizing plates, a retardation at each wavelength (product of birefringence x film thickness) will cause a corresponding color appearance. , the liquid crystal image becomes extremely unclear, making it difficult to use practically.

In the present invention, "aromatic polyester resin" refers to
The general formula is (wherein, A monovalent group selected from 1 to 20 alkyl, allyl, aralkyl, alkoxyl, alkoxyl and allyl alkoxyl groups, substituted products thereof, halogens and mixtures thereof, p and q are p+q-o to g
, where m and n are O or 1, where n is 0 when m = 1) Any synthetic resin may be used as long as it is a synthetic resin, but in particular, in formula (1), some or all of The following general formula (wherein, ) is preferable, more preferably the aromatic dicarboxylic acid component in formula 1(, i3) has a molar ratio of (1010 to 7/3), preferably 9/
1 (terephthalic acid/isophthalic acid) and the molar ratio is 2/1 (bisphenol A/3.3?5.
It is a co-M configuration consisting of 5'tetramethylbisphenol F). Furthermore, the molecular weight of the aromatic polyester resin used in the present invention is not particularly limited, but
- Generally from 50,000 to 150,000, preferably from 60,000 to 130,000.

is a polymer or copolymer of two or more types of bisphenols or bisphenols and a small amount of divalent compound,
Furthermore, it can also be obtained by a mixture of these. As a copolymer, for example, aromatic dicarbonate is a single or mixed component of terephthalic acid and isophthalic acid.

Examples of preferred bisphenol components include 2.2. −
Bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-di5ee-7'thyl-4-hydroxyphenyl)propane, 2,2-bis(
3,5-di-tert-butyl4-hydroxyphenyl)propane, bis(3,5-dimethyl-4-hydroxyphenyl)methane, 1, ]-bis(3,5-dimethyl-4-hydroxyphenyl)ethane, 1 .1-bis(3
, 5-dimethyl-4-hydroxyphenyl)cyclohexane, bis(3,5-dimethousand-4-hydroxyphenyl)ketone, bis(3,5-dimethousand-4-hydroxyphenyl)ether, bis(3,5- dimethyl-4-hydroxyphenyl) sulfide, 2,2-bis(3,5
-dimethyl-4-hydroxyphenyl)hexafluoropropane, 2,2-bis(3,5-dimethoxy-4-hydroxyphenyl)propane, bis(3,5-dimethoxy-4-hydroxyphenyl)methane, 2,2 −Bis(
3-methoxy-4-hydroxy-5-methylphenyl)
Propane, bis(3-methoxy-4-hydroxy-5-
methylphenyl)methane, bis(3,5-diphenyl-
4-hydroxyphenyl)methane, 2,2-bis(3,
5-diphenoxy-4-hydroxyphenyl)propane, bis(3-phenoxy-4-hydroxy-5-methyl)methane, 4,4'-dihydroxy-3,3? 5.5
? -tetramethylbiphenyl, 4,4'-dihydroxy-3,3:5.5'-tetraethylbiphenyl, bis(
4-hydroxy-3-methylphenyl) sulfone, bis(4-hydroxy-3,5-dimethylphenyl) sulfone, bis(4-hydroxy-3-ethylphenyl) sulfone, bis(4-hydroxy-3,5-diethyl) phenyl) sulfone, bis(4-hydroxy-3,5-dimethoxyphenyl) sulfone, bis(4-hydroxy-3,
Examples include 5-jethoxyphenyl) sulfone.

These bisphenol components having a substituent at the 3.5-position include 4,4'-dihydroxydiphenyl, bis(4
-hydroxyphenyl)methane, 1.1-bis(4-hydroxyphenyl)ethane, 2.2-bis(4-hydroxyphenyl)pronogne, hydroquinone, resorcinol, and the like. It is also possible to use bisphenolic dyes such as phenolphthalein, fluorescein, naphthophthalein, and thymolphthalein.

In addition, as a mixture, the above-mentioned aromatic polyester resin and, for example, polycarbonate (PC), polyarylate (PAR), polyethersulfone (PPB), polysulfone (P81i'), polyamideimide (FAI), polyesterimide ( P
13I), polyimide (PI), etc., or a mixture of two or more of them, which are compatible with each other, especially the above aromatic polyester resin and polycarbonate +- (PC) and/or
Or a mixture with polyarylate (PAR) is suitable.

T of the aromatic polyester resin thus obtained
Although g is not particularly limited, it is preferably 300 to 300.
The temperature is 150°C, more preferably 300 to 180°C.

Furthermore, the method for polymerizing the aromatic polyester resin is not particularly limited, and conventionally known polymerization methods can be employed.

For example, a melt polymerization method in which aromatic dicarboxylic acid and bisphenol are reacted in a high-temperature molten state, a solution polymerization method in which aromatic dicarboxylic acid dichloride and bisphenol are reacted in an organic solvent in the presence of an amine as a deoxidizing agent, and an aromatic dicarboxylic acid There is an interfacial polymerization method in which acid dichloride and bisphenol are dissolved in two types of solvents that are incompatible with each other, and then the two liquids are mixed and stirred in the presence of an alkali to cause a polycondensation reaction at the interface. However, among these, coloring, foreign matter, high degree of polymerization, and Tg
From this point of view, the interfacial polymerization method is preferable.

Furthermore, the term "antioxidant" used in the present invention refers to a substance that prevents or suppresses the yellowing that occurs when aromatic polyester resin is exposed to high temperatures, does not reduce transparency, and has a melting point of 100°C. or more, preferably 150°C or more,
More preferably, it is a substance that has a temperature of 200° C. or higher, and specifically, phenol-based and phosphite-based compounds, among which phenol-based compounds are preferred. In particular, the effects of using the above phenol compound and the above phosphite compound together can be expected to be even more effective.

Examples of the phenolic compound include 2,5-di-tert-butylhydroquinone, 4,4'-isopropylidene bisphenol, 4,4'-butyldenbis(3-methyl-6-tcrtbutylphenol, 1
, 1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-methylenebis(2,6-di-tert)
butylphenol), 2,6-bis(2'-hydroxy-3'tcrt3butyl-5'-methylbenzyl)
4-Methyl-phenol, 1,1,3-tris(2-methyl-4-hydroxy-5-tertbutylphenyl)butane, 1,3,5-tris-methyl-2,4,6-
Tris(3,5-di-tertbutyl-4-hydroxybenzyl)benzene, tris(3,5-di-tert
Butyl-4-hydroxyphenyl)ine cyanurate, 4゜4'-thiobis(3-methyl-6-tertbutylphenol), 2,4.6-1-di-tertbutylphenol, 4-hydroxymethyl-2,6- G-t
ertbutylphenol, cyclohexylphenol,
2.2'-methylenebis(4-methyl-6-tcrtbutylphenol), 2.2'-methylenebis(4-ethyl-6-tartbutylphenol), tetrakis[methylene-3(3,5-di-tcrtbutylphenol) Oxyphenyl)propionate comethane, tris(/
-(3,5-di-tartbutyl-4-hydroxyphenyl)globionyloxyethyl]isocyanate and 4,4'-thiobis(2-methyl-5-tertbutylphenol), among others, 1,3.5- 1-Lismethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene-tris(
3,5-di-tert-butyl-4-hydroxyphenyl)in cyanurate, 4,4'-butylidene-bis(
3-methyl-6-tartbutylphenol), 2,5
-di-tert-butylnohydroquinone, 4,4'-methylenebis(2,6-di-tert-butylphenol)
and 4,4'-isopropylidene bisphenol are preferred.

As a mataphosphite compound, tris(2,4-
(di-tertbutylphenyl) phosphite and a compound represented by the following structural formula.

The amount of antioxidant used in the present invention is 100 yen of resin.
0.01 to 10 parts by weight based on part Kt, more preferably 0
．． It is 1 to 3 parts by weight.

These antioxidants may be blended with the aromatic polyester resin by any conventional method, such as mixing resin granules or powder with a V-type blender, Henschel mixer super mixer, kneader, etc. Alternatively, a method in which the resin is dissolved in an organic solvent and sprayed onto resin granules or powder may also be used. Generally, when producing an aromatic polyester by interfacial polycondensation, the resin is obtained as a solution of an organic solvent, so it is convenient to add it to the reaction system or to the solution after post-treatment such as neutralization and washing with water.

In order to obtain an optically isotropic film from the film composition obtained in this way, there are no particular restrictions and any film manufacturing method can be adopted, but the following method is used: Explain an example.

(1) Production process for the original film The method for producing the original film is not particularly limited, and films obtained by any method such as a hot melting method or a solution casting method may be used, and the solution casting method is particularly preferred. It is. Examples of the hot melting method include an extrusion method, a gear rendering method, and a press method, and examples of the solution casting method include a solvent casting method and a sol casting method. Among them, the solvent casting method is preferable.

The solvent used in the solution casting method is not particularly limited, but generally, for example, methylene chloride, 1
．． 1.2.2-tetrachloroethane, tetrahydrofuran, dioxane, dimethylformaldehyde, dimethylacetoformaldehyde, toluene, etc. are used, among which methylene chloride and 1.1.2.2-tetrachloroethane are preferred.

(2) Film heat treatment process This process is a process set to impart optical isotropy to the original film obtained in the above process, and includes (1) film preheating process and (2) cooling process. There is.

(2-1> Preheating step The above film is heated to [glass transition temperature (hereinafter referred to as rTgJ) + tO)"C1, preferably (Tg + 20) °C, more preferably (Tg + 35)"C or higher for 1 minute, preferably 2 minutes, more preferably is a step of preheating for 3 minutes or more.

(2-2) Cooling process (slow cooling process) The film preheated in the preheating process (1 to 0.01
)'C/sec, preferably (0,8-0.05)'C/sec, more preferably (0,5-0,1)'C/sec, to (Tg-15) °C. , preferably (Tg-6
5) up to 'C, more preferably (Tg-Zoo)'C
This step is particularly called the "slow cooling step".

Further, in the slow cooling step, it is also possible to partially shorten the cooling time if necessary.

That is, as detailed below, in the slow cooling step, the film is slowly cooled and then rapidly cooled.

(2-2') Cooling process [(slow cooling → rapid cooling) process] The film preheated in the preheating process is heated to (1g + 20) °C, preferably (Tg + 10) °C, more preferably CTg ± 0) °C. , (1~0.
01)”(:7 seconds, preferably (0.8~0.05
)”C7 seconds, more preferably (0.5 to 0.1)”C
Slow cooling at a cooling rate of 7 seconds, then to (Tg-15)'C, preferably to (Tg-fi5)C, more preferably to (Tg-100)'C: (50-1)C/ seconds, preferably (10-1)°C/second, more preferably (
5-1) A step of rapidly cooling at a cooling rate of °C/second (hereinafter this step is referred to as "slow cooling/quenching step").

In this way, a film with excellent birefringence can be obtained by undergoing the above-mentioned elaborate cooling process.

The thickness of the film thus obtained is not particularly limited, but is generally 1 to 500μ, preferably 10 to 200μ, and more preferably 25 to 100μ.

As described above, the aromatic polyester resin film obtained by the present invention is a colorless and transparent film with significantly improved yellowing appearance compared to conventional films, and is optically isotropic. It is an extremely useful film with excellent properties and will make an extremely large contribution to the industry.

The present invention will be described in more detail in Examples below, but the present invention is not limited to the Examples.

Example 1 A methylene chloride solution of a mixed acid chloride in which the molar ratio of terephthalic acid dichloride and ifphthalic acid dichloride is 9:1 and a bisphenol of 3.3? 5. My 7. was obtained by an alkaline aqueous solution interfacial polymerization method in which the molar ratio of s'-tetramethylbisphenol F was 2=1. Oman Tg21
A polyarylate resin at 5°C was obtained.

A dope of methylene chloride solution (15 wt.) of this resin was prepared. An antioxidant (A-1) shown in Table 1 was placed in the resin solution in an amount of 0.3 parts by weight per 100 parts by weight of the resin and stirred.

This was dried using film casting equipment at 40°C for 0.5 minutes and 60°C for 1 minute, and then both sides were dried using tenter equipment (15 minutes).
0°C 1 minute, 230°C 5 minutes) and heat fixation (250°C 3 minutes)
was carried out, and a bone-dry polyarylate film (about 75μ thick) was prepared.
4) was obtained.

Next, this film was preheated to 255°C for 5 minutes using a heat treatment device (clip tenter), and then heated from 255°C to 200°C.
It was continuously cooled down to ℃ for 3 minutes.

The birefringence of this film was 3 nm, and an optically isotropic polyarylate film with a thickness of about 75 μm was obtained.

This film was tested for yellowing and film surface blowout properties. The results are shown in Table 1.

Example 2.3.4 In Examples 2.3 and 4, instead of the antioxidant A-1 used in Example 1, antioxidant A-2 was used as shown in Table 1.
, Person-3, and A-1 and P-1 were used alone or in combination, but the same procedure as in Example 1 was carried out. A polyarylate film was obtained.

Comparative Example 1.2 Comparative Examples 1 and 2 are antioxidant A-1 used in Example 1.
Instead, as shown in Table 1, the procedure was exactly as in Example 1 except that no antioxidant was used or P-2 was used, and optically equivalent samples with birefringence of 3 nm were obtained. A polyarylate film with a thickness of 75 μm was obtained.

The test results for these films are shown in Table 1.

Table 1 Antioxidant A-1: 1,3.5-tris-methyl-2,4,
6-tris(3,5-sheet tcrtbutyl-4-hydroxybenzyl)benzene
Melting point 244℃A-2 Nitris (3,5-di-tcrtbutyl-4-hydroxyphenyl)isocyanurate e point 221℃A-
3: 4,4'-butylidene-bis(3-methy) L/
6-tertbutylphenol) Melting point 2
08°C P-1: l-lith(2,4-di-tertbutylphenyl)phosphite
Melting point: 183℃ P-2: ) Lysosyl phosphite is liquid at room temperature. Here, Tg is the glass transition temperature, and when the following thermodynamic derivative is plotted against temperature, a discontinuity occurs. The relationship between temperature, density, specific volume, specific heat, acoustic coefficient, or refractive index is determined.

In addition, the physical properties were measured and evaluated using the values determined by the following method.

(11 Glass transition temperature (Tg) PerkinElmer DSC (differential scanning calorimeter)!N
Measured using a mold. That is, sample polymer 10II
9 in a D8C device, and heated the sample to a room temperature of 10°C.
The temperature was raised at a rate of 1/min, and the glass transition point was measured.

(2) Birefringent Nippon Kogaku Kogyo ■ polarizing microscope (OPT I PH0T-
It was measured by the Senarmont compensator method using POLffl).

(3) Yellowing ■ Spectrophotometer (double monochromator) manufactured by Takasu Seisakusho
The total light transmittance at 390 nm was measured using a self-spectrophotometer (UV-365).

l is 70 or more and less than 80% Δl is 7
Less than 0 x Blowability The film test piece was left at an ambient temperature of 150° C. for 30 minutes, and the blowability of the antioxidant onto the film surface was evaluated with the naked eye.

No blowing is observed ○ No blowing is observed (force) Δ Blowing is observed 5 with a spectrophotometer
00+sm to 750 nm) was measured, and the average value was calculated.

(4)

Claims (1)

[Scope of Claims] 1. A film composition characterized by containing at least an aromatic polyester resin and an antioxidant. 2. The main components of the aromatic polyester resin are ▲Mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, X is a substituted or unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms, -O -, -S-, -SO_2
- and -CO-, R and R each have 1 to 2 carbon atoms
a monovalent group selected from 0 alkyl, allyl, aralkyl, alkoxyl, allyloxyl and allylalkoxyl groups, substituted products thereof, halogen and mixtures thereof, p and q are p+q
2. The film composition according to claim 1, wherein m and n are 0 or 1, provided that when m=1, n≠0). 3. In the formula (I), some or all are ▲ mathematical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, X, m, n are the same as in formula (I), R_1 to R_
The film composition according to claim 2, wherein 4 represents a monovalent group selected from an alkyl group having 1 to 4 carbon atoms, an alkoxyl group, a phenyl group, and a halogen atom. 4. In the aromatic dicarboxylic acid component in the formula (II), the molar ratio is (10/0 to 7/3) (terephthalic acid/isophthalic acid) and the molar ratio is 2/1 (bisphenol A/3). , 3', 5, 5' tetramethylbisphenol F). 5. The film composition according to claims 1 and 5, wherein the antioxidant has a melting point of 100°C or higher. 6. The film composition according to claim 1, wherein the antioxidant is a phenolic compound.