JP3083860B2 - Transparent film with moisture resistance and heat resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent film having moisture resistance and heat resistance, and more particularly to a transparent film that can be suitably used as an optical film in the field of optoelectronics.

[0002]

2. Description of the Related Art In recent years, in the field of optoelectronics, there has been a demand for a highly transparent optical film having excellent moisture proof and heat resistance. About vinylidene chloride on this film surface,
Attempts have been made to improve the moisture-proof properties by forming a moisture-proof layer made of polypropylene or the like.

[0003]

However, when the moisture-proof layer is formed of vinylidene chloride, there is a drawback that coloring or generation of hydrochloric acid gas occurs at 100 ° C. or higher. Has a drawback that when it exceeds 150 ° C., the transparency is reduced. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a transparent film having excellent moisture resistance and heat resistance which can be suitably used as an optical film and the like, and having high transparency.

[0004]

A transparent film according to the present invention for achieving the above object has a structure in which an amorphous polyolefin layer is formed on at least one surface of a specific amorphous aromatic polymer film. Become.

[0005] The amorphous aromatic polymer film of the present invention may be terephthalic acid, isophthalic acid or terephthalic acid.
And a mixture of phosphoric acid and isophthalic acid with the general formula
Amorphous fragrance obtained by reaction with the dihydric phenols represented
It is an aromatic polyester film.

[0006]

Embedded image

Wherein p and q are integers of 0 to 4, R ¹ , R
² is an alkyl group having 1 to 4 carbon atoms which may be the same or different, and when p or q is 2 to 4, each R ¹ and R ² may be the same or different. May be. X is a direct bond, an alkylene group, an alkylidene group (the hydrogen atoms in these alkylene groups and alkylidene groups may be substituted with a hydrocarbon group, a halogen group, a halogenated hydrocarbon group), -O-, -S-,-
SO -, - it is or -CO- - SO _2. ]

Specific examples of the dihydric phenol represented by the general formula shown in Chemical Formula 2 include 2,2-bis (4'-hydroxyphenyl) propane and bis (4-hydroxyphenyl)
Methane, 2,2-bis (4′-hydroxyphenyl) butane, 3,3-bis (4′-hydroxyphenyl) pentane, 4,4-bis (4′-hydroxyphenyl) heptane, 4,4 ′-( α-methylbenzylidene) bisphenol, 4,4-bis (4′-hydroxyphenyl)-
2,5-dimethylheptane, bis (4-hydroxyphenyl) diphenylmethane, 2,2-bis (4′-hydroxyphenyl) octane, bis (4′-hydroxyphenyl) -4-fluorophenylmethane, bis (3,5 −
Dimethyl-4hydroxyphenyl) methane, 2,2-bis (3 ′, 5′-dimethyl-4′-hydroxyphenyl) propane, bis (3,5-dimethyl-4-hydroxyphenyl) phenylethane, bis (3- Methyl-4-
Hydroxyphenyl) diphenylmethane, bis (3,5
-Dimethyl-4-hydroxyphenyl) sulfone is exemplified. These may be used alone or in combination of two or more as necessary.

The above-mentioned amorphous aromatic polymer film is obtained by, for example, an extrusion molding method or a casting method from a solution in which the amorphous aromatic polymer is dissolved in a solvent. Among them, the casting method is preferable in terms of uniformity of the film thickness and leveling property of the surface. The film thickness is usually several μm to 800 μm, preferably 10 to 300 μm
It is. When high temperature treatment is sometimes performed in the processing process, the above-mentioned amorphous aromatic polyester film having particularly excellent heat resistance is suitable as the amorphous aromatic polymer film.

The amorphous polyolefin layer in the present invention functions as a moisture-proof layer. When the moisture-proof layer is formed of a crystalline polyolefin such as polypropylene, crystallization is gradually caused by a heating-cooling cycle in a processing process, resulting in a film having low transparency, especially having a large haze. In order to prevent this, it is necessary to limit the heating upper limit temperature to about 150 ° C., and there is a problem in processing. However, in the present invention,
A moisture-proof layer is formed from an amorphous polyolefin having excellent heat resistance. Therefore, crystallization does not occur even if the heating-cooling cycle is repeated, and the transparency does not decrease. Amorphous polyolefins generally have a temperature lower by about 10 to 20 ° C. than their glass transition point (Tg) as the limit of heat resistance (working temperature), but use an aromatic polyester film having excellent heat resistance as a base film. In this case, even if the amorphous polyolefin is heated to a temperature 50 ° C. or more higher than the Tg of the amorphous polyolefin, the film can be composited without causing deformation of the amorphous polyolefin layer. When a liquid crystal display device is manufactured by combining the transparent film according to the present invention with a transparent conductive film, the Tg is 120 ° due to the processing process.
It is preferable to use a C or higher amorphous polyolefin. The thickness of the amorphous polyolefin layer is preferably in the range of 1 μm to about 2/5 of the thickness of the base film, and is preferably 5 μm.
m is more preferably in the range of about 3/10 of the thickness of the base film. When the thickness is less than 1 μm, the moisture resistance becomes insufficient, and when the thickness is more than 2/5 of the thickness of the base film, the heat resistance of the obtained composite film decreases. Examples of the amorphous polyolefin include those obtained by increasing the Tg by cyclizing the olefin to be amorphous.
Examples of commercially available products include ZEONEX (trade name) manufactured by Zeon Corporation and APO resin manufactured by Mitsui Petrochemical Company.

In the production of the composite film according to the present invention, the amorphous aromatic polymer film and the amorphous polyolefin may be dry-laminated, or the amorphous aromatic polymer film may be coated on the amorphous aromatic polymer film. After casting the polyolefin solution, it may be dried. Further, an appropriate adhesive may be used to increase the adhesion strength between the two.
If necessary, a transparent hard coat layer for protecting the surface may be formed on one or both sides of the transparent film according to the present invention, or a gas barrier layer may be formed. The transparent film according to the present invention can be suitably used in the field of optoelectronics. That is, for example, at present, glass is mainly used as a transparent electrode of a liquid crystal display element, but by replacing it with the transparent film according to the present invention, it is light and hard to break, and has excellent heat resistance and moisture resistance. Display element can be obtained.

[0012]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and the present invention may be practiced by appropriately changing the gist of the invention. Is possible.

Example 1 (A) Synthesis of amorphous aromatic polyester 1.14 g of 2,2-bis (4'-hydroxyphenyl) propane and bis (3,5-dimethyl-4-hydroxyphenyl) methane 1.28 g and 1.5 g of para-t-butylphenol were added to and dissolved in 20 ml of a 1.25 N aqueous NaOH solution. A solution prepared by dissolving 1.91 g of terephthalic acid chloride and 0.04 g of trioctylmethylammonium chloride (phase transfer catalyst) in 20 ml of orthodichlorobenzene was added to this aqueous solution, and the mixture was reacted at room temperature for 3 hours while stirring. . After decanting the aqueous layer of the reaction mixture, the same amount of water was added to the organic layer and neutralized with a small amount of hydrochloric acid. Further, the organic layer was washed with water five times, and then poured into a large amount of methanol to precipitate a solid aromatic polyester. At this time, the yield of the polyester was almost 100%. The polyester had a Tg of 250 ° C. and a reduced viscosity ηs which was an index of molecular weight.
p / c is 0.60 (32 ° C., 0.32 in chloroform)
g / deciliter). (B) Preparation of Amorphous Aromatic Polyester Film The polyester obtained in the above (A) was dissolved in methylene chloride so as to have a concentration of 15% by weight, and the obtained solution was cast on a SUS plate. Place on plate, 50 °
20 minutes at C, 20 minutes at 100 ° C, 20 minutes at 150 ° C
Heat fix at 250 ° C for 10 minutes,
An m-thick film was obtained. (C) Preparation of Composite Film Zeonex manufactured by Zeon Corporation as an amorphous polyolefin was dissolved in toluene to obtain a 20% solution. This solution was cast on the amorphous aromatic polyester film obtained in the above (B) to form a moisture-proof layer having a thickness of 20 μm. Table 1 shows the optical properties (total light transmittance and haze) and moisture permeability of each of the films obtained in (B) and (C) above. Also, 1
The optical properties and moisture permeability after heating at 80 ° C. for 1 hour are also shown. ASTM D100 for total light transmittance and haze
3 and the moisture permeability were measured in accordance with JIS Z 0208, respectively.

[0014]

[Table 1]

From Table 1, it can be seen that there is almost no change in the optical characteristics and the moisture permeability after heating. Further, no change in appearance such as wrinkles and shrinkage was observed in the film after heating.

(Example 2) (A) Synthesis of amorphous aromatic polyester 2,2-bis (4'-hydroxyphenyl) propane 2
0.11 g, bis (3,5-dimethyl-4-hydroxyphenyl) methane 15.06 g, para-t-butylphenol 0.95 g, sodium hydrosulfite 0.26 g, 5N-NaOH aqueous solution 78.2 ml, water 176 .8 ml under nitrogen atmosphere for 30
The mixture was mixed in a 0 ml eggplant type flask and cooled to 5 ° C. to prepare an aqueous alkaline solution of dihydric phenol. Separately, 21.32 g of terephthalic acid chloride and 9.14 g of isophthalic acid chloride were dissolved in 255 ml of methylene chloride in a 300 ml eggplant type flask under a nitrogen atmosphere, and cooled to 5 ° C. In a 1-liter separable flask, 137 ml of water and 0.16 g of benzyltributylammonium chloride (phase transfer catalyst) were charged under a nitrogen atmosphere.
And cooled. While the cooling liquid was vigorously stirred, the above two liquids were simultaneously added continuously by a pump over 10 minutes separately. Two hours after completion of the addition, a solution of 0.42 g of benzoyl chloride dissolved in 5 ml of methylene chloride was added, and stirring was stopped 20 minutes later. After decanting the aqueous layer, the same amount of water was added and neutralized with a small amount of hydrochloric acid while stirring. After decanting and desalting by water washing are repeated, 300 ml of methylene chloride is added for dilution. The methylene chloride was distilled off until the polymer concentration reached 15% by weight. The reduced viscosity ηsp /
c is 0.90 (0.32 g / 32 ° C in chloroform)
Deciliters). (B) Preparation of Amorphous Aromatic Polyester Film The methylene chloride solution of the polyester obtained in (A) was
Cast it on a US plate, place it on a hot plate,
Heat set at 50 ° C. for 20 minutes, 100 ° C. for 20 minutes, 150 ° C. for 20 minutes, and 250 ° C. for 10 minutes.
A 0 μm thick film was obtained. (C) Preparation of Composite Film Zeonex manufactured by Zeon Corporation as an amorphous polyolefin was dissolved in toluene to obtain a 20% solution. This solution was cast on the amorphous aromatic polyester film obtained in the above (B) to form a moisture-proof layer having a thickness of 20 μm. Table 1 shows the optical properties (total light transmittance and haze) and moisture permeability of each of the films obtained in (B) and (C) above. Table 1 also shows the optical characteristics after heating at 180 ° C. for one hour. Table 1 shows that there is no change in the optical characteristics after heating. Further, no change in appearance such as wrinkles and shrinkage was observed in the film after heating.

Example 3 (A) Synthesis of amorphous aromatic polyester 30.45 g of 4,4 '-(α-methylbenzylidene) bisphenol, 1.58 of para-t-butylphenol
g, sodium hydrosulfite 0.53 g, 5N
153 ml of an aqueous NaOH solution and 361 ml of water were mixed in a 1.5-liter separable flask under a nitrogen atmosphere, and cooled to 5 ° C. to prepare an alkaline aqueous solution of a dihydric phenol. On the other hand, 30.45 g of terephthalic acid chloride and 30.45 g of isophthalic acid chloride.
45 g was dissolved in 500 ml of methylene chloride in a 1 liter flask under a nitrogen atmosphere and cooled to 5 ° C. Further, 200 ml of water and 0.31 g of benzyltributylammonium chloride (phase transfer catalyst) were charged in a 1-liter separable flask under a nitrogen atmosphere, and cooled to 5 ° C. While the cooling liquid was vigorously stirred, the above two liquids were simultaneously added to each of the pumps continuously over 10 minutes. Two hours after completion of the addition, a solution of 0.42 g of benzoyl chloride dissolved in 5 ml of methylene chloride was added, and stirring was stopped 20 minutes later. After decanting the aqueous layer, the same amount of water was added and neutralized with a small amount of hydrochloric acid while stirring. After decanting and desalting by water washing are repeated, 300 ml of methylene chloride is added for dilution. The methylene chloride was distilled off until the polymer concentration reached 15% by weight. The reduced viscosity ηsp / c of this polyester was 0.80 (32 ° C., 0.32 g / deciliter in chloroform). Also, TMA
Tg determined by (Thermo Mechanical Analysis) method was 240 ° C. (B) Preparation of Amorphous Aromatic Polyester Film The methylene chloride solution of the polyester obtained in (A) was
Cast on a US plate, place on a hot plate and place at room temperature
The film was heat-set at 150 ° C. for 15 minutes and then at 250 ° C. for 10 minutes to obtain a film having a thickness of about 70 μm. (C) Preparation of Composite Film Zeonex manufactured by Zeon Corporation as an amorphous polyolefin was dissolved in toluene to obtain a 20% solution. This solution was cast on the amorphous aromatic polyester film obtained in B above to form a moisture-proof layer having a thickness of 20 μm. Table 1 shows the optical properties (total light transmittance and haze) and moisture permeability of each of the films obtained in (B) and (C) above. Table 1 shows that
The optical properties after heating at 80 ° C. for 1 hour are also shown. Table 1 shows that there is no change in the optical characteristics after heating.
Further, no change in appearance such as wrinkles and shrinkage was observed in the film after heating.

Example 4 (A) Synthesis of Amorphous Aromatic Polyester 36.21 g of bis (3,5-dimethyl-4-hydroxyphenyl) sulfone, 0.2 g of para-t-butylphenol.
95g, sodium hydrosulfite 0.25g,
58 ml of 5N-NaOH aqueous solution and 200 ml of water were mixed in a 300 ml eggplant type flask under a nitrogen atmosphere, and cooled to 5 ° C. to prepare an alkaline aqueous solution of dihydric phenol. On the other hand, terephthalic acid chloride 12.18 g and isophthalic acid chloride 1
2.18 g was dissolved in 250 ml of methylene chloride in a 300 ml eggplant type flask under a nitrogen atmosphere and cooled to 5 ° C. In a 1 liter separable flask, 100 ml of water and 0.14 of trioctylmethylammonium chloride (phase transfer catalyst) were added.
g was charged in a nitrogen atmosphere and cooled to 5 ° C. in the same manner. While the cooling liquid was vigorously stirred, the above two liquids were simultaneously added to each of the pumps continuously over 10 minutes. Two hours after completion of the addition, 0.21 of benzoyl chloride was added.
g was dissolved in 5 ml of methylene chloride, and stirring was stopped after 20 minutes. After decanting the aqueous layer, the same amount of water was added and neutralized with a small amount of hydrochloric acid while stirring. After decanting and desalting by water washing are repeated, 300 ml of methylene chloride is added for dilution. Remove,
Methylene chloride was further distilled until the polymer concentration reached 15% by weight. The reduced viscosity ηsp / c of this polyester was 0.95 (32 ° C., 0.32 g / deciliter in chloroform). (B) Preparation of Amorphous Aromatic Polyester Film The methylene chloride solution of the polyester obtained in (A) was
Cast on a US plate, place on a hot plate, 50 °
C. for 20 minutes, at 150 ° C. for 20 minutes, and further at 300 ° C. for 10 minutes to obtain a film having a thickness of about 70 μm. (C) Preparation of Composite Film Zeonex manufactured by Zeon Corporation as an amorphous polyolefin was dissolved in toluene to obtain a 20% solution. This solution was cast on the amorphous aromatic polyester film obtained in the above (B) to form a moisture-proof layer having a thickness of 20 μm. Table 1 shows the optical properties (total light transmittance and haze) and moisture permeability of each of the films obtained in (B) and (C) above. Table 1 also shows the optical characteristics after heating at 180 ° C. for one hour. Table 1 shows that there is no change in the optical characteristics after heating. Further, no change in appearance such as wrinkles and shrinkage was observed in the film after heating.

(Comparative Example) 7 prepared in (B) of Example 2
15 μm on 0 μm thick amorphous aromatic polyester film
A composite film was prepared by laminating an m-thick polypropylene film, and a test was performed in the same manner as in Examples 1 to 4. Table 1 shows the results. The haze after heating at 180 ° C. for one hour was large, indicating that there was a problem in heat resistance.

[0020]

The transparent film according to the present invention is excellent in moisture resistance and heat resistance and has high transparency, so that the present invention has excellent unique effects such as being suitable for use as an optical film.

Continuation of the front page (56) References JP-A-52-7780 (JP, A) JP-A-59-167252 (JP, A) JP-A-4-185331 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (2)

(57) [Claims] 1. A transparent film having moisture resistance and heat resistance, wherein an amorphous polyolefin layer is formed on at least one surface of an amorphous aromatic polymer film,
The amorphous aromatic polymer film is obtained by reacting terephthalic acid, isophthalic acid, or a mixture of terephthalic acid and isophthalic acid with a dihydric phenol represented by the general formula shown in Chemical Formula 1. A transparent film having moisture resistance and heat resistance, which is a crystalline aromatic polyester film. Embedded image [In the formula, p and q are integers of 0 to 4, R ¹ and R ² are an alkyl group having 1 to 4 carbon atoms which may be the same or different, and p or q is 2 to 4. In the case of 4, each R ¹ ,
R ² may be the same or different.
X is a direct bond, an alkylene group, an alkylidene group (the hydrogen atoms in these alkylene groups and alkylidene groups may be substituted with a hydrocarbon group, a halogen group, a halogenated hydrocarbon group), -O-, -S-, -SO-,-
SO ₂ — or —CO—. ] 2. The transparent film having moisture resistance and heat resistance according to claim 1, wherein said amorphous polyolefin layer is a layer comprising an amorphous polyolefin having a glass transition point of 120 ° C. or higher.