METHACRYLIC RESIN COMPOSITION AND USE THEREOF

Abstract

A methacrylic resin composition comprising 100 parts by mass of a methacrylic resin having an amount of a terminal double bond of less than 0.012% by mole and an amount of a bonded sulfur atom of preferably less than 0.25% by mole; 510.sup.6 to 910.sup.3 part by mass of a metal element having an atomic number of not more than 20 (preferably lithium element and aluminum element); and 0.025 to 0.50 part by mass of a hindered phenol antioxidant such as 2,6-bis(1,1-dimethylethyl)-4-methylphenol, wherein the methacrylic resin composition, when being exposed to a nitrogen gas atmosphere at 290 C. for 15 minutes, has a thermogravimetric retention of not less than 98% by mass.

Claims

1. A methacrylic resin composition comprising: 100 parts by mass of a methacrylic resin having an amount of a terminal double bond of less than 0.012% by mole; 510.sup.6 to 910.sup.3 part by mass of a metal element having an atomic number of not more than 20; and 0.025 to 0.50 part by mass of a hindered phenol antioxidant, wherein the methacrylic resin composition, when being exposed to a nitrogen gas atmosphere at 290 C. for 15 minutes, has a thermogravimetric retention of not less than 98% by mass.

2. The methacrylic resin composition according to claim 1, wherein the methacrylic resin has an amount of a bonded sulfur atom of less than 0.25% by mole.

3. The methacrylic resin composition according to claim 1, wherein the methacrylic resin has a triad syndiotacticity (rr) of not less than 50%.

4. The methacrylic resin composition according to claim 1, wherein the methacrylic resin has a weight average molecular weight of 50 thousand to 200 thousand.

5. The methacrylic resin composition according to claim 1, wherein the methacrylic resin comprises not less than 99% by mass of a structural unit derived from methyl methacrylate.

6. A pelletized forming material comprising the methacrylic resin composition according to claim 1.

7. A shaped product comprising the methacrylic resin composition according to claim 1.

8. A film comprising the methacrylic resin composition according to claim 1.

9. The film according to claim 8, having a thickness of 10 to 50 m.

10. The film according to claim 8, being uniaxially stretched or biaxially stretched to 1.5 to 8 times in an area ratio.

Description

EXAMPLES

[0103] The present invention is described more specifically by showing Examples and Comparative Examples. The present invention is not limited to the following Examples. Measurement of physical properties and the like is performed by the following methods.

(Polymerization Conversion)

[0104] To a gas chromatograph GC-14A manufactured by Shimadzu Corporation, a column, Inert CAP 1 (df=0.4 m, 0.25 mm.I.D.60 m) manufactured by GL Sciences Inc. was attached. Measurement was performed under conditions where the injection temperature was 180 C., the detector temperature was 180 C., and the column temperature was raised from 60 C. (maintained for 5 minutes) to 200 C. at a temperature raising rate of 10 C./minute and then maintained at 200 C. for 10 minutes. Based on results of the measurement, the polymerization conversion was determined by calculation.

[Evaluation of Methacrylic Resin]

(Weight Average Molecular Weight (Mw), Molecular Weight Distribution (Mw/Mn))

[0105] A chromatogram was measured by gel permeation chromatography (GPC) under the following conditions, and the results were subjected to calculation to obtain values expressed in terms of a molecular weight of standard polystyrene. The base line was defined as a line connecting a point where the slope is changed from zero to positive on the higher molecular weight side of a peak when viewed from the side of earlier retention time with a point where the slope is changed from negative to zero on the lower molecular weight side of the peak when viewed from the side of earlier retention time.

[0106] GPC device: HLC-8320 manufactured by Tosoh Corporation

[0107] Detector: Differential refractometer detector

[0108] Column: Column obtained by connecting two TSKgel SuperMultipore HZM-M columns and a Super HZ4000 column manufactured by Tosoh Corporation, in series

[0109] Eluting agent: Tetrahydrofuran

[0110] Flow rate of eluting agent: 0.35 ml/minute

[0111] Column temperature: 40 C.

[0112] Calibration line: Drawn by connecting 10 data points of standard polystyrene

(Triad Syndiotacticity (rr))

[0113] A .sup.1H-NMR spectrum of a methacrylic resin was measured using a nuclear magnetic resonance spectrometer (manufactured by Bruker, ULTRA SHIELD 400 PLUS), with deuterated chloroform used as a solvent, under conditions at room temperature and integration times of 64. The resulting spectrum was used to determine the square measure (X) of a region from 0.6 to 0.95 ppm and the square measure (Y) of a region from 0.6 to 1.35 ppm with the spectrum of TMS being taken as 0 ppm, followed by calculation of the triad syndiotacticity (rr) by a formula: (X/Y)100.

(Glass Transition Temperature Tg)

[0114] Using a differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-50 (product number)) and according to JIS K7121, a DSC curve was obtained under conditions of increasing the temperature of a methacrylic resin once to 230 C., cooling to room temperature, and then increasing the temperature again from room temperature to 230 C. at 10 C./minute. The midpoint glass transition temperature found from the DSC curve measured at the second increasing temperature was designated as the glass transition temperature Tg.

(Terminal Double Bond Amount)

[0115] A methacrylic resin was dissolved in deuterated chloroform to obtain a solution having a concentration of 15 to 20% by mass. Tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate)europium was added to the solution at a concentration of 10% by mass relative to the mass of the methacrylic resin. The resulting solution was subjected to integration measurement using NMR (JNM-GX270 manufactured by JEOL Ltd.) over 12 hours. From the resultant .sup.1H-NMR spectrum, the total X.sub.c of the integrated intensity of a signal derived from the terminal double bond part (resonance frequency: 5.5 ppm and 6.2 ppm) and the integrated intensity Y.sub.p of a signal derived from a methoxy group in a methyl methacrylate main chain (resonance frequency: 3.6 ppm) were measured, and the terminal double bond amount D.sub.p [% by mole] of the methacrylic resin was calculated by the following formula.

D.sub.p=[(3X.sub.p)/(2Y.sub.p)]100

(Amount of Bonded Sulfur Atom)

[0116] A methacrylic resin was dissolved in chloroform to obtain a solution, and this solution was added to n-hexane to obtain a precipitate. The obtained precipitate was dried under vacuum at 80 C. for not less than 12 hours. An appropriate amount of the dried product was precisely weighed, and set to a sulfur combustion apparatus and decomposed in a reaction furnace at 400 C., the generated gas was allowed to pass through a 900 C. furnace, and then absorbed by 0.3% hydrogen peroxide solution. The resultant liquid was appropriately diluted with pure water, and sulfuric acid ion was quantified by ion chromatography (ICS-1500 manufactured by DIONEX, column: AS12A). Mass W.sub.p (% by mass) of sulfur atom per mass of the dried product was calculated. Then, the amount S.sub.p of the bonded sulfur atom (% by mole) was calculated by the following formula.

S.sub.p=(W.sub.p/32)100

[Evaluation of Methacrylic Resin Composition]

(Metal Element Content)

[0117] To 0.15 g of the methacrylic resin composition, 10 ml of nitric acid was added. The resultant was irradiated using microwave irradiation apparatus ETHOS-1600 at 220 C. for 25 minutes. After allowing to cool, ion exchanged water was added to the resultant liquid to obtain 20 ml of solution. Quantitative analysis of the metal element for the resultant solution was performed using an ICP luminescent spectroscopic analyzer (Vista Pro manufactured by SII). The content of metal element (part by mass) relative to methacrylic resin 100 parts by mass was calculated.

(Thermogravimetric Retention)

[0118] Using a thermogravimetric analyzer (manufactured by Shimadzu Corporation, TGA-50 (product number)), mass change of a methacrylic resin composition was recorded under conditions of increasing the temperature from 50 C. to 290 C. at 20 C./min under a nitrogen atmosphere at a nitrogen flow rate of 50 ml/min, and then maintaining the temperature at 290 C. for 20 minutes under nitrogen atmosphere. On the basis of the mass (X.sub.1c) at 50 C. (thermogravimetric retention: 100% by mass), based on the mass (X.sub.2c) when maintaining at 290 C. for 15 minutes, the thermal decomposition resistance was evaluated according to the following formula.

Thermogravimetric retention (% by mass)=(X.sub.2c/X.sub.1c)100 (% by mass)

(Total Light Transmittance)

[0119] A methacrylic resin composition was subjected to heat press forming to give a shaped product having a thickness of 3.2 mm. The total light transmittance of the shaped product was measured according to JIS K7361-1 with a haze meter (manufactured by Murakami Color Research Laboratory, HM-150).

(Haze)

[0120] A methacrylic resin composition was subjected to heat press forming to obtain a shaped product having a thickness of 3.2 mm. The haze of the shaped product was measured according to JIS K7136 using a haze meter (manufactured by Murakami Color Research Laboratory, HM-150).

(Glass Transition Temperature Tg)

[0121] With a differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-50 (product number)) and according to JIS K7121, a DSC curve was obtained under conditions of increasing the temperature of a methacrylic resin composition once to 230 C., cooling to room temperature, and then increasing the temperature again from room temperature to 230 C. at 10 C./minute. The midpoint glass transition temperature found from the DSC curve measured at the second increasing temperature was determined for use as the glass transition temperature.

[Evaluation of Film]

(Roll Smudges)

[0122] A methacrylic resin composition was extruded with the use of a film forming apparatus (FS-5 model manufactured by Optical Control System) at a cylinder temperature and a T-die temperature of 290 C., a lip space of 0.5 mm, a discharge rate of 2.7 kg/hr, a roll temperature of 85 C., and a film take-up speed of 2.2 m/minute to obtain a film having a thickness of 100 m. During the film formation, observation of roll smudges was performed. The observation for roll smudges was performed by visual examination of the surface of a metal roll as the film was being sent forward. Evaluation was performed based on the lapse of time from the start of the forming until the occurrence of white haze on the entire surface of the roll.

A: White haze was not generated for not less than 30 minutes
B: White haze was generated in less than 30 minutes.

(Production Example 1) (Production of Methacrylic Resin [A-a])

[0123] A 5-L glass reaction vessel equipped with a stirring blade and a three-way cock was purged with nitrogen. At room temperature, 1600 g of toluene, 80 g of 1,2-dimethoxyethane, 73.3 g (42.3 mmol) of a 0.45-M solution of isobutyl bis(2,6-di-t-butyl-4-methylphenoxy)aluminum in toluene, and 8.44 g (14.1 mmol) of a 1.3-M solution of sec-butyllithium in a solvent comprising 95% of cyclohexane and 5% of n-hexane were charged in the vessel. Thereto while stirring at 15 C. to 20 C., 550 g of purified methyl methacrylate was added dropwise over 30 minutes. After completion of the dropwise addition, stirring was performed at 15 C. for 90 minutes. The color of the solution turned from yellow to colorless. At this point, the polymerization conversion of methyl methacrylate was 100%.

[0124] Next, the following purification was performed so that the amount of Al element was 410.sup.4 to 110.sup.3 part by mass and the amount of Li element was 310.sup.5 to 510.sup.4 part by mass relative to 100 parts by mass of the methacrylic resin.

[0125] Firstly, to the resulting solution, toluene was added for dilution. Then, the diluted solution was poured in a large amount of methanol to obtain a precipitate. The precipitate was removed from the liquid by filtration, and was then washed several times. The resulting precipitate was dried at 80 C. and 140 Pa for 24 hours to obtain a methacrylic resin [A-a] having Mw of 68000, Mw/Mn of 1.06, a syndiotacticity (rr) of 73%, a glass transition temperature of 130 C., and a content of structural unit derived from methyl methacrylate of 100% by mass. In the methacrylic resin [A-a], relative to 100 parts by mass of the methacrylic resin, the amount of Al element was 510.sup.4 part by mass (5 ppm), and the amount of Li element was 0.510.sup.4 part by mass (0.5 ppm).

(Production Example 2) (Production of Methacrylic Resin [A-b])

[0126] In an autoclave equipped with a stirrer and a sampling tube which had been purged with nitrogen, 100 parts by mass of purified methyl methacrylate, 0.0074 part by mass of 2,2-azobis(2-methylpropionitrile) (hydrogen abstraction ability: 1%, 1-hour half-life temperature: 83 C.), and 0.28 part by mass of n-octyl mercaptan were added, followed by stirring to give a raw material liquid. In the raw material liquid, nitrogen was introduced for removing oxygen dissolved in the raw material liquid.

[0127] From the autoclave, the raw material liquid was fed to the tank reactor to be placed up to capacity of the tank reactor. With the temperature maintained at 140 C., a polymerization reaction was initiated in a batch mode. When the conversion reached 55% by mass, the raw material liquid was continuously fed from the autoclave to the tank reactor, while the reaction product solution was discharged from the tank reactor at a flow rate corresponding to the flow rate of the raw material liquid being fed. In this way, the polymerization reaction was switched to a continuous-flow mode for mean residence time of 150 minutes and at a temperature of 140 C. The polymerization conversion in a steady state of the continuous-flow mode was 52% by mass.

[0128] The liquid discharged from the tank reactor was fed to a multitubular heat exchanger at an internal temperature of 230 C. at a flow rate such that the mean residence time was 2 minutes, and warmed. The warmed liquid was introduced in a flash evaporator for removal of volatile matter mainly comprising unreacted monomer to obtain a molten resin. The molten resin was fed in a devolatizing twin screw extruder equipped with vent at an internal temperature of 260 C., and was extruded in a form of a strand. The resulting strand was cut with a pelletizer to obtain a methacrylic resin [A-b] having Mw of 82000, Mw/Mn of 1.92, a syndiotacticity (rr) of 51%, a glass transition temperature of 120 C., and a content of structural unit derived from methyl methacrylate of 100% by mass. In the methacrylic resin [A-b], the amount of Al element was 0 part by mass, and the amount of Li element was 0 part by mass relative to 100 parts by mass of the methacrylic resin.

(Production Example 3) (Production of Methacrylic Resin [A-c])

[0129] A methacrylic resin [A-c] was produced by mixing and kneading 20 parts by mass of the methacrylic resin [A-a] and 80 parts by mass of the methacrylic resin [A-b], and extruding the resultant product at 260 C. with the use of a twin screw extruder (manufactured by Technovel Corporation, trade name: KZW20TW-45MG-NH-600). In the methacrylic resin [A-c], the amount of Al element was 110.sup.4 part by mass (1 ppm), and the amount of Li element was 0.110.sup.4 part by mass (0.1 ppm) relative to 100 parts by mass of the methacrylic resin.

(Production Example 4) (Production of Methacrylic Resin [A-d])

[0130] In an autoclave equipped with a stirrer and a sampling tube which had been purged with nitrogen, 97.4 parts by mass of purified methyl methacrylate, 2.6 parts by mass of methyl acrylate, 0.0074 part by mass of 2,2-azobis(2-methylpropionitrile) (hydrogen abstraction ability: 1%, 1-hour half-life temperature: 83 C.), and 0.28 part by mass of n-octyl mercaptan were added, followed by stirring to give a raw material liquid. In the raw material liquid, nitrogen was introduced for removing oxygen dissolved in the raw material liquid.

[0131] From the autoclave, the raw material liquid was fed to the tank reactor to be placed up to capacity of the tank reactor. With the temperature maintained at 180 C., a polymerization reaction was initiated in a batch mode. When the polymerization conversion reached 55% by mass, the raw material liquid was fed from the autoclave to the tank reactor, while the liquid was discharged from the tank reactor at a flow rate corresponding to the flow rate of the raw material liquid being fed. Thus, a continuous-flow mode polymerization reaction was performed for mean residence time of 150 minutes at a temperature of 180 C. The polymerization conversion in a steady state of the continuous-flow mode was 55% by mass.

[0132] The liquid discharged from the tank reactor was fed in a multitubular heat exchanger at an internal temperature of 230 C. at a flow rate such that the mean residence time was 2 minutes, and warmed. The warmed liquid was charged in a flash evaporation apparatus for removal of volatile matter mainly comprising unreacted monomer to obtain a molten resin. The molten resin was fed into a devolatizing twin screw extruder equipped with vent at an internal temperature of 260 C., and was extruded in the form of a strand. The resulting strand was cut with a pelletizer to obtain a methacrylic resin [A-d] having Mw of 87000, Mw/Mn of 1.78, a syndiotacticity (rr) of 48%, a glass transition temperature of 117 C., and a content of structural unit derived from methyl methacrylate of 98.5% by mass. In the methacrylic resin [A-d], the amount of Al element was 0 part by mass, and the amount of Li element was 0 part by mass relative to 100 parts by mass of the methacrylic resin.

(Production Example 5) (Production of Methacrylic Resin [A-e])

[0133] A glass reaction vessel equipped with a stirring blade and a three-way cock was purged with nitrogen. At room temperature, in the vessel, 1600 g of toluene, 80 g of 1,2-dimethoxyethane, 73.3 g (42.3 mmol) of a 0.45-M solution of isobutyl bis(2,6-di-t-butyl-4-methyl phenoxy)aluminum in toluene, and 8.44 g (14.1 mmol) of a 1.3-M solution of sec-butyllithium in a solvent comprising 95% of cyclohexane and 5% of n-hexane were charged. Thereto while stirring at 15 C. to 20 C., 550 g of purified methyl methacrylate was added dropwise to the resultant product over 30 minutes. After completion of the dropwise addition, stirring was performed at 15 C. for 90 minutes. The color of the solution turned from yellow to colorless. At this point, the polymerization conversion of methyl methacrylate was 100%.

[0134] The resultant solution was dried at 130 C. and at 140 Pa for 24 hours, and then the resultant product was fed into a devolatizing twin screw extruder equipped with vent at an internal temperature of 260 C. to be extruded in the form of strand. The resulting strand was cut with a pelletizer to obtain a methacrylic resin [A-e] having Mw of 68000, Mw/Mn of 1.06, a syndiotacticity (rr) of 73%, a glass transition temperature of 130 C., and a content of structural unit derived from methyl methacrylate of 100% by mass. In the methacrylic resin [A-e], the amount of Al element was 100010.sup.4 part by mass, and the amount of Li element was 32010.sup.4 part by mass relative to 100 parts by mass of the methacrylic resin.

(Production Example 6) (Production of Methacrylic Resin [A-f])

[0135] A methacrylic resin [A-f] was produced by mixing and kneading 40 parts by mass of the methacrylic resin [A-a] and 60 parts by mass of the methacrylic resin [A-b], and extruding the resultant product at 260 C. with the use of a twin screw extruder (manufactured by Technovel Corporation, trade name: KZW20TW-45MG-NH-600). In the methacrylic resin [A-f], the amount of Al element was 210.sup.4 part by mass (2 ppm), and the amount of Li element was 0.210.sup.4 part by mass (0.2 ppm) relative to 100 parts by mass of the methacrylic resin.

[0136] Physical properties of the methacrylic resins [A-a] to [A-f] are shown in Table 1.

TABLE-US-00001 TABLE 1 Production example 1 2 3 4 5 6 Methacrylic resin A-a A-b A-c A-d A-e A-f terminal double bond 0 0.014 0.011 0.020 0 0.008 amount [% by mole] bonded sulfur atom 0 0.160 0.130 0.015 0 0.100 amount [% by mole] Syndiotacticity (rr) [%] 73 51 56 48 73 60 Tg [ C.] 130 120 122 117 130 124 Mw 68,000 82,000 78,000 87,000 68,000 73,000 Mw/Mn 1.06 1.92 1.52 1.78 1.06 1.50 Content of structural unit 100 100 100 98.5 100 100 from MMA [% by mass] MMA: methyl methacrylate

[0137] Hindered phenol antioxidants [C-a] and [C-b] were prepared.

C-a: 2,6-bis(1,1-dimethylethyl)-4-methylphenol (manufactured by Wako Pure Chemical Industries, Ltd.; BHT)
C-b: pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF; product name: IRGANOX 1010)

Example 1

[0138] A methacrylic resin composition [1] was produced by mixing 100 parts by mass of the methacrylic resin [A-a] and 0.15 part by mass of the hindered phenol antioxidant [C-a], and kneading and extruding the resultant product at 260 C. with the use of a twin screw extruder (manufactured by Technovel Corporation, trade name: KZW20TW-45MG-NH-600).

[0139] The methacrylic resin composition [1] was subjected to heat press forming to obtain a platy shaped product having a size of 50 mm50 mm3.2 mm. This shaped product was subjected to measurements for total light transmittance, haze, and glass transition temperature. Physical properties of the methacrylic resin composition [1] are shown in Table 2.

[0140] The methacrylic resin composition [1] was dried at 80 C. for 12 hours. And the methacrylic resin composition [1] was extruded through a T-die having a width of 150 mm at a resin temperature of 260 C. using a 20-mm single screw extruder (manufactured by OCS), and the resultant product was taken by rolls having a surface temperature of 85 C. to obtain an unstretched film having a width of 110 mm and a thickness of 160 m. The evaluation results are shown in Table 2.

[0141] The unstretched film having a thickness of 160 m obtained as described above was cut into a small piece of 100 mm100 mm so that two sides of the small piece were parallel to the direction of extrusion. The small piece was set to a pantograph type biaxial stretching tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.), at a temperature of glass transition temperature+10 C., the small piece was stretched twofold in a direction parallel to the direction of extrusion at a stretching speed of 150%/minute, twofold in a direction orthogonal to the direction of extrusion at a stretching speed of 150%/minute, and followed by maintaining it for 10 seconds. Thereafter, the small piece was taken out at room temperature and rapidly cooled down to obtain a biaxially stretched film having a thickness of 40 m.

Examples 2 to 6, Comparative Examples 1 to 6

[0142] Methacrylic resin compositions [2] to [12] were produced and evaluated in the same manner as in Example 1 except that blending is performed as shown in Tables 2 and 3. Evaluation results are shown in Tables 2 and 3.

TABLE-US-00002 TABLE 2 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Methacrylic resin composition [1] [2] [3] [4] [5] [6] Methacrylic resin[parts. by mass] A-a 100 100 97.5 A-c 100 100 A-e 2.5 A-f 100 Metal element[10.sup.4 part. by mass] 5.5 5.5 1.1 1.1 39 2.2 (itemize) Al 5.0 5.0 1.0 1.0 30 2.0 Li 0.5 0.5 0.1 0.1 9 0.2 Hindered phenol antioxidant[part by mass] C-a 0.15 0.05 0.03 0 0.15 0.06 C-b 0 0 0 0.15 0 0 Physical properties of methacrylic resin terminal double bond 0 0 0.011 0.011 0 0.08 amount [% by mole] bonded sulfur atom 0 0 0.130 0.130 0 0.100 amount [% by mole] Mw 68000 68000 78000 78000 68000 73000 Syndiotacticity (rr) [%] 73 73 56 56 73 60 Evaluation results of methacrylic resin composition Thermogravimetric retention [%] 98.9 98.7 98.0 98.0 98.0 98.7 Tg [ C.] 130 130 122 122 130 124 Total Light Transmittance [%] 92 92 92 92 88 92 Haze [%] 0.2 0.2 0.2 0.2 0.3 0.2 Evaluation results of unstretched film Thickness [m] 160 160 160 160 160 160 Roll smudges A A A B A A

TABLE-US-00003 TABLE 3 Comp. Comp. Comp. Comp. Comp. Comp. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Methacrylic resin composition [7] [8] [9] [10] [11] [12] Methacrylic resin[parts. by mass] A-a 100 90.5 A-b 100 100 100 A-d 100 A-e 9.5 Metal element[10.sup.4 part by mass] 5.5 0 0 0 132 0 (itemize) Al 5.0 0 0 0 100 0 Li 0.5 0 0 0 32 0 Hindered phenol antioxidant[part by mass] C-a 0 0.05 0.15 0 0.15 0.15 C-b 0 0 0 0.15 0 0 Physical properties of methacrylic resin terminal double bond 0 0.014 0.014 0.014 0 0.020 amount [% by mole] bonded sulfur atom 0 0.160 0.160 0.160 0 0.015 amount [% by mole] Mw 68000 82000 82000 82000 68000 87000 Syndiotacticity (rr) [%] 73 51 51 51 73 48 Evaluation results of methacrylic resin composition Thermogravimetric retention [%] 64.9 90.7 96.6 96.5 98.0 95.6 Tg [ C.] 130 120 120 120 130 117 Total Light Transmittance [%] 92 92 92 92 82 92 Haze [%] 0.2 0.2 0.2 0.2 0.4 0.2 Evaluation results of unstretched film Thickness [m] 160 160 160 160 160 160 Roll smudges A A A B A A