JP2859038B2 - Polycarbonate resin film or sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film or sheet suitable for optical use such as a protective film or sheet for a polarizing plate support plate, an optical recording medium such as an optical desk, or a reflector substrate.

[0002]

2. Description of the Related Art A polarizing plate used in an LCD (Liquid Crystal Display) cannot be put to practical use, such as durability, with a polarizing film alone. Therefore, a transparent synthetic resin film or sheet is adhered on one or both sides for protection. It has a structure.
As a protective film or sheet called a polarizing plate support plate, a transparent film or sheet of a cellulose triacetate resin (hereinafter abbreviated as TAC) has conventionally been used.

However, since the TAC film or sheet has high moisture permeability, protection against deterioration of the polarizing film due to permeated moisture is not satisfactory, and there is a problem that the polarizing plate decolorizes under high temperature and high humidity conditions. With the expansion of the use environment of LCDs, such as the incorporation of LCDs into vehicles, there has been a demand for a polarizing plate support plate with low moisture permeability.

As a polarizing plate support plate, a stretched film or sheet of acrylic resin having excellent transparency, and ethylene-
A film obtained by casting a saponified vinyl acetate copolymer has been proposed, but a stretched film or sheet of an acrylic resin has a drawback in that the heat resistance itself is poor,
Films of saponified ethylene-vinyl acetate copolymer are inferior in transparency, and have disadvantages such as limited production method to casting method and environmental problems such as solvent recovery. No. 55-155307, Tokuhei 3-23881).

Attempts have been made to use a transparent film or sheet to prevent the recording surface of an optical recording medium such as an optical disc from being damaged. However, TAC is not applicable because it absorbs wrinkles due to moisture absorption. At present, there is no suitable thing.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, that is, there is little change in moisture permeability and dimensional change in moisture absorption, and transparency, weather (light) resistance, birefringence, etc. By providing a film or sheet suitable for optical applications such as a polarizing plate support plate, a protective film or sheet of an optical recording medium such as an optical disk, or a reflector substrate, which has excellent optical properties and heat resistance, and has little coloring. is there.

[0007]

The present inventors have made intensive studies on solving the above-mentioned problems, and as a result, surprisingly, it has been found that a certain alicyclic polycarbonate resin film or sheet has a moisture permeability and a change in moisture absorption dimensional change. The present invention was found to be excellent in optical characteristics such as transparency, weather resistance (light), and birefringence, and in heat resistance, and was less colored.

[0008] An object of the present invention is composed of repeating units represented by the following general formula [1] to [3], one
The repeating unit represented by the general formula [1] (hereinafter referred to as “general formula
The repeating unit represented by [m] is abbreviated as the unit [m].
Is sometimes substantially equal to the total mole fraction (y + z) of the mole fraction (y) of the unit [2] and the mole fraction (z) of the unit [3]. The mole fraction (y) of [2] is in the range of 20 mol% to 50 mol%, and is made of an alicyclic polycarbonate resin having a number average molecular weight of 20,000 to 200,000, and an alkali metal;
This is achieved by a polycarbonate resin film or sheet characterized by being substantially free of alkaline earth metals, titanium, zinc, lead, manganese, antimony, germanium or compounds of these metals.

[0009]

Embedded image However, in the general formula [1], n is 0, 1 or 2, and in the general formula [3], A is a divalent saturated aliphatic hydrocarbon group having 20 or less carbon atoms, a saturated alicyclic hydrocarbon. Or an aromatic hydrocarbon group.

The content (x) of the structural unit of the general formula [1] is substantially 50 mol%. The content (y) of the structural unit of the general formula [2] is from 20 to 50 mol%, preferably from 3 to
0 to 50 mol%. If the content is less than 20 mol%, the moisture permeability and the dimensional change in moisture absorption tend to increase, which is not preferable. The content (z) of the structural unit of the general formula [3] is basically 50-y mol%.

The structural unit represented by the general formula [1] is specifically as follows, and when the structural unit is a repeating unit in which n is 1 or 2, the heat resistance of the film or sheet is preferably high.

When n = 0

[0013]

Embedded image When n = 1

[0014]

Embedded image When n = 2

[0015]

Embedded image Further, specific examples of the structural unit of the general formula [3] include the following.

When A is a saturated aliphatic hydrocarbon

[0017]

Embedded image When A is a saturated alicyclic hydrocarbon

[0018]

Embedded image When A is an aromatic hydrocarbon

[0019]

Embedded image For applications requiring low birefringence, such as a polarizing plate support plate, a film or sheet with low birefringence can be obtained even if some orientation occurs during molding. Aliphatic or saturated alicyclic hydrocarbon structures are preferably selected. In particular, when A is a saturated alicyclic hydrocarbon, the heat resistance is high, and the dimensional change in moisture absorption is small, which is preferable. When a film or sheet is formed by a method that does not cause orientation, or in applications where birefringence is not particularly a problem, an aromatic hydrocarbon structure having a large orientation birefringence can be selected. For example, there is an advantage in that heat resistance is increased.

Each of the structural units represented by the general formulas [1] and [3] may be only one type, or two or more types may be mixed. Further, other structural units may be included as long as the effects of the present invention are not impaired. The substitution amount is usually 10 mol% or less.

The molecular weight of the alicyclic polycarbonate resin is required to be the number-average molecular weight 20,000 to 200,000 (in terms of polystyrene), preferably 30000
It is ～150000. When the molecular weight is less than 20,000, the mechanical strength of the film or sheet of the present invention becomes insufficient, and when it exceeds 200,000, film formation becomes difficult.

It is essential that the film or sheet of the present invention contains substantially no alkali metal, alkaline earth metal, titanium, zinc, lead, manganese, antimony, germanium or a compound of these metals. In general, the polycarbonate resin, which is the base resin of the film or sheet of the present invention, is prepared by a solvent method using an acid chloride (phosgene for the structural unit represented by the general formula [2]) corresponding to the structural unit and a diol as raw materials. It is manufactured by a melting method using an acid, ester, diol or alkoxide corresponding to the structural unit as a raw material. In the former, an alkali metal hydroxide is used for dehydrochlorination, and in the latter, polymerization is carried out at a practical rate. 20,000 to 20,000
In order to obtain a resin having a polymerization degree of 0, tetraalkyl orthotitanate, zinc acetate, antimony oxide, germanium oxide, various alkoxides such as potassium-t-butoxide and sodium methoxide, alkali metals such as lithium and sodium, hydrogenation It has been necessary to add a metal such as a hydride of an alkali metal such as lithium or sodium hydride or a metal halide or a compound of these metals as a catalyst.

The film or sheet produced from the resin thus obtained was excellent in properties such as transparency, moisture permeability, dimensional stability of moisture absorption, heat resistance, etc., but was lightly colored yellow. There is a problem as an optical film or sheet. The present inventors have found that the pale yellow color is not derived from the essence of the resin, and a film or sheet produced by a conventional method includes alkali metals, alkaline earth metals or metals such as titanium mixed from a catalyst or the like. These compounds are contained, and it is found out that this is the cause of coloring. By using a film or a sheet substantially free of these metals or metal compounds, coloring is prevented and the optical It has been found that the following film or sheet can be achieved.

Here, the phrase "contains substantially no metal or metal compound" means that the metal or metal compound is not more than the amount that can function practically as a polymerization catalyst.
ppm or less, preferably 1 ppm or less. The film or sheet of the present invention substantially free of these metals or metal compounds includes, for example, a dihydroxy compound corresponding to the general formula [1], a diphenyl carbonate corresponding to the general formula [2] and a general formula [3]. From the corresponding ester, tetraphenylboronic acid tetra-
The resin can be manufactured by a novel polymerization method using a borate ester such as n-butylammonium as a catalyst, and then formed into a film or sheet shape so that these metal compounds are not mixed.

As a method for forming the film or sheet, known methods can be employed, but an extrusion method is a preferred method. As the melting temperature in the extrusion molding, a temperature in the range of usually 180 to 350 ° C is used, and particularly preferably 200 to 300 ° C is used. In the film or sheet of the present invention, it is preferable that the molecular orientation is small, since the birefringence is small and the dimensional stability upon heating is excellent.

A resin modifier such as a plasticizer, a dye / pigment, an ultraviolet absorber, an antioxidant, and a lubricant is added to the film or sheet of the present invention as long as the effects of the present invention are not impaired.
Alternatively, other resins can be blended.

The thickness of the film or sheet of the present invention is
Although not essentially limited, generally 10 μm to 2 μm
0 mm is preferred .

[0028]

The film or sheet of the present invention has less coloring, is excellent in optical properties such as transparency, weather (light) resistance, birefringence and heat resistance, and has a small change in moisture absorption dimension and small moisture permeability. There is.

The water vapor transmission rate is determined by the general-purpose bisphenol A
System polycarbonate resin film or sheet,
Despite high as 35g / m ² /24hr/0.1mm, for example, n in the general formula [1] is 1, those mole fraction of the general formula [2] is 50%, surprisingly, 5 g / m ²
/ 24 hr / 0.1 mm.

The low water vapor transmission rate is a very desirable property as a support plate for a polyvinyl alcohol polarizing plate using iodine as a polarizing element, which is problematic in performance degradation caused by passing moisture. The water vapor transmission rate of the film or sheet of the present invention is about 1 times that of the conventionally used TAC.
/ 100, and by using this as a polarizing plate support plate, a polarizing plate with improved durability became possible.

The film or sheet of the present invention is also excellent in moisture dimensional stability, at n in the general formula [1] is 1, one
The film mole fraction is 50% of the general formula [2], after drying 23 ° C., is allowed to have is dimensional change in 95% humidity environment for 7 days was only 0.01%. Changes in dimensions due to changes in humidity cause many problems in optical film applications, and there is a demand for improved dimensional stability of moisture absorption. For example,
Protective film made TAC as a protective film or sheet of the recording surface of the CD or LD, etc. light desk is proposed, and moisture absorption by the environmental humidity change, into practical use for wrinkles was not optimum et al. The dimensional change in moisture absorption of the film or sheet of the present invention is about 1/50 that of the TAC film,
Further, the film or sheet of the present invention has a low birefringence, and for the first time, a protective film or sheet for an optical recording medium such as a CD or LD has been made possible.

As the protective film or sheet, it is convenient to use the alicyclic polycarbonate resin film or sheet of the present invention in the form of an adhesive laminated thereon, and as the adhesive, a transparent adhesive is used. For example, polyurethane-based, epoxy-based, and acrylic-based ones can be used. Laminate the adhesive on the protected surface,
A method of attaching a protective film or sheet to this is also possible.

The film or sheet of the present invention can withstand a temperature of 105 ° C. or higher without being deformed or deteriorated, and has excellent weather resistance (light). It is suitable as a reflector used on the back side of lighting for improving efficiency.

The film or sheet of the present invention, which is excellent in heat resistance, moisture absorption dimensional stability and transparency, and has little coloring, is also preferable for uses of transparent films or sheets other than optical uses, for example, for nameplates.

In the present invention, those having a thickness of less than 254 μm are distinguished from films and those having a thickness of 254 μm or more are distinguished from sheets.

The method for measuring the characteristic values will be described below. Transparency: total light transmittance, haze (ASTM D100
3) was evaluated. -Colorimetry: Measured according to JIS K7105 (C light source,
10 ° field of view, transmission method). -Metal analysis: Analyzed by atomic absorption method. Birefringence: Observed with a strain tester SVP-10 manufactured by Toshiba Glass Co., Ltd. -Moisture absorption dimensional stability: After drying in an oven at 80 ° C for 48 hours, it was evaluated by dimensional change after leaving it in an environment of 23 ° C and 95% humidity for 7 days. -Water vapor transmission rate: measured according to JIS Z0208. -Number average molecular weight: Determined by GPC measurement in comparison with a standard polystyrene molecular weight (polystyrene conversion).

[0037]

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

Example 1 13.4 kg of trans-2,3-di (hydroxymethyl) -perhydro-1, 4: 5,8-dimethanonaphthalene
And 12.9 Kg of diphenyl carbonate and 0.7 of tetra-n-butylammonium tetraphenylboronate
g was charged and the inside of the reaction vessel was replaced with nitrogen. 100 nitrogen
After the temperature was raised to 180 ° C. while flowing at a rate of 1 liter / hour, stirring was started.
The temperature was raised to 0 ° C. and maintained at the same temperature for 2 hours. During this time, 71% of the theoretical phenol was distilled out. Then, the pressure inside the system was gradually reduced while maintaining the same temperature, and the pressure was reduced to 0.2 over 1 hour.
mmHg. Further, after stirring was continued for 45 minutes under the same conditions, the stirring was stopped, and the pressure was returned to normal pressure by introducing nitrogen into the system. Next, the polymer produced by a gear pump attached to the reaction tank was discharged in a strand form, and cut with a cutter to obtain an alicyclic polycarbonate resin having a repeating structure represented by the following general formula [4]. The number average molecular weight of the obtained resin was 38,000.

[0039]

Embedded image This was extruded at an extrusion temperature of 250 ° C. to produce a 100 μm film.

This film was subjected to metal analysis by atomic absorption spectroscopy. Alkali metal, alkaline earth metal, titanium, zinc,
The contents of all elements of lead, manganese, antimony and germanium were 1 ppm or less.

Total light transmittance 93%, haze 0.3%
The colorimetric values of L * are 96.39 and a * is-
It was a colorless film excellent in transparency, with little coloration, 0.01 and b * of 0.19. The water vapor permeability was as low as 5g / m ² /24hr/0.1mm. After drying, it was left in an environment of 23 ° C. and 95% humidity for 7 days, but the dimensional change was only 0.01%.

When a film was placed between a pair of orthogonal polarizing plates using a strain tester and rotated, the brightness and hue of the orthogonal polarizing plates did not change, and no birefringence was observed. Further, although the sample was heated to 120 ° C., no deformation was observed.

This film was adhered to both surfaces of a polyvinyl alcohol polarizing film using iodine having a thickness of 30 μm as a polarizing element with a urethane adhesive to prepare a polarizing plate. The polarizing plate was excellent in polarizing performance with two parallel transmittances of 40% and a degree of polarization of 99.9% or more. A durability test was performed under the conditions of 80 ° C. and 90%.
The change was slight at 5% and the degree of polarization was 98.8%.

On the other hand, an 80 μm triacetate film (FT-80, manufactured by Fuji Photo Film Co., Ltd.) used as a support plate for a polarizing plate has a water vapor transmission rate of 380 g / m 2.
Was ^{2 /24hr/0.1mm.} Using this as a support plate, a polarizing plate was produced, and a durability test was performed at 80 ° C. and 90%. The initial polarization performance was such that the parallel transmittance of the two sheets was 41% and the degree of polarization was 99.9% or more.
The parallel transmittance of the two sheets was 51%, and the degree of polarization was 75.3%, making it unsuitable for use as a polarizing plate.

An adhesive was partially applied to the film of the present invention so that only the inner and outer peripheral portions of the laser disk were bonded, and the film was bonded to the laser disk. The humidity was changed from 10% to 95% at 25 ° C., but no wrinkling occurred. When the laser disk was reproduced with the protective film attached, no abnormality was found.

On the other hand, an 80 μm triacetate film (FT-80, manufactured by Fuji Photo Film Co., Ltd.) was similarly adhered to a laser disk, and when the humidity was changed from 10% to 95% at 25 ° C., wrinkles were found. Occurs
Playback has been disabled.

Comparative Example 1 In Example 1, instead of 0.7 g of tetra-n-butylammonium tetraphenylboronate as a catalyst,
A resin was produced in the same manner except that 0.4 g of lithium hydride was used, and a film was formed to produce a 100 μm film.

This film was subjected to metal analysis by an atomic absorption method, and lithium element was detected at 30 ppm.

Total light transmittance 92%, haze 0.4%
And the transparency was good, but the colorimetric value of L * was 96.
12, a * was -0.04 and b * was 1.32, indicating a yellowish film.

EXAMPLE 2 In Example 1, trans-2,3-di (hydroxymethyl) -perhydro-1, 4: 5,8-dimethanonaphthalene was replaced by 13.4 kg of trans-2,3-di ( (Hydroxymethyl) -perhydro-1, 4: 5, 10:
6,9 One bird methanolate anthracene number average molecular weight by the same method except for using 17.4Kg is 62000
To produce an alicyclic polycarbonate resin comprising a repeating structure represented by the general formula [5], to form a film of 80μ by extrusion molding.

[0051]

Embedded image Metal analysis of this film by atomic absorption spectrometry revealed that the content of each of the alkali metals, alkaline earth metals, titanium, zinc, lead, manganese, antimony, and germanium was 1 ppm or less.

Total light transmittance 93%, haze 0.3%
The colorimetric values are as follows: L * is 96.31, a * is-
0.02 and b * of 0.28, indicating that the film was a colorless film with excellent transparency and little coloration. The water vapor permeability was as low as 5g / m ² /24hr/0.1 mm. After drying, it was left in an environment of 23 ° C. and 95% humidity for 7 days, but the dimensional change was only 0.01%.

No birefringence was observed, and the sample was heated to 150 ° C., but no deformation was observed.

Example 3 In Example 1, trans-2,3-di (hydroxymethyl) -perhydro-1, 4: 5,8-dimethanonaphthalene was replaced with 13.4 kg of trans-2,3-di ( (Hydroxymethyl) -perhydro-1, 4: 5,8-dimethanonaphthalene 6.7 kg and trans-2,3-di (hydroxymethyl) bicyclo [2.2.1] heptane 4.7 kg According to the method, the number average molecular weight of the structural unit represented by the general formula [6] is 48.
000 alicyclic polycarbonate resins were manufactured, and 300 μm sheets were prepared by extrusion molding.

[0055]

Embedded image Metal analysis of this sheet by atomic absorption spectroscopy revealed that alkali metals, alkaline earth metals, titanium, zinc, lead, manganese,
The content of antimony and germanium elements is 1p
pm or less.

Total light transmittance 93%, haze 0.4%
The colorimetric values of L * are 96.36 and a * is-
The colorless sheet was excellent in transparency, with little coloration being recognized as 0.02 and b * being 0.22. After drying, 23
It was left in an environment at a temperature of 95 ° C. and humidity of 95% for 7 days, but the dimensional change was only 0.02%.

No birefringence was observed, and the sample was heated to 105 ° C., but no deformation was observed.

Example 4 trans-2,3-di (hydroxymethyl) -perhydro-1, 4: 5,8-dimethanonaphthalene 13.4K
g, 9.0 kg of diphenyl carbonate, 3.5 kg of diphenyl terephthalate and 0.7 g of tetra-n-butylammonium tetraphenylboronate as a catalyst are represented by the general formula [7] in the same manner as in Example 1. An alicyclic polycarbonate resin having a number average molecular weight of 35,000 consisting of structural units was produced, and was extruded to obtain 8
A 0 μm film was produced.

[0059]

Embedded image Metal analysis of this film by atomic absorption spectrometry revealed that the content of each of the alkali metals, alkaline earth metals, titanium, zinc, lead, manganese, antimony, and germanium was 1 ppm or less.

Total light transmittance 92%, haze 0.3
%, The colorimetric values were 96.25 for L *, -0.02 for a *,
b * was 0.31 and the film had good transparency and little coloring.

[0061]

According to the present invention, a film or sheet of a polycarbonate resin having an alicyclic structural unit is used for optical applications with little moisture permeability, small change in moisture absorption, excellent transparency, weather resistance (light) resistance and heat resistance, and little coloring. Suitable films or sheets have been achieved. This film or sheet is suitable for use as a polarizing plate support plate, a protective film or sheet for an optical recording medium such as an optical disk, a reflector substrate, and the like.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C08G 63/64 C08G 64/02

Claims (1)

(57) [Claims] 1. A repeating unit represented by the following general formula [1] , comprising repeating units represented by the following general formulas [1] to [3] :
The unit molar fraction (x) is a repeating unit represented by the general formula [2].
Unit mole fraction (y) and repetition represented by general formula [3]
Total mole fraction of the mole fraction of units (z) (y + z) is substantially equal, the formula the molar fraction of the repeating unit represented by [2] (y) is 50 mol% or less than 20 mol% The number average molecular weight in the range is made of an alicyclic polycarbonate resin having a molecular weight of 20,000 or more and 200,000 or less, an alkali metal,
A polycarbonate-based resin film or sheet substantially free of alkaline earth metals, titanium, zinc, lead, manganese, antimony, germanium or compounds of these metals. Embedded image However, in the general formula [1], n is 0, 1 or 2, and in the general formula [3], A is a divalent saturated aliphatic hydrocarbon group having 20 or less carbon atoms, a saturated alicyclic hydrocarbon. Or an aromatic hydrocarbon group.