JP2003183423A - Biaxially oriented film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester-based biaxially oriented film having pinhole resistance, impact resistance, transparency and heat resistance. <P>SOLUTION: The biaxially oriented film comprises a polyester resin having a dicarboxylic acid constitutional unit and a diol constitutional unit, wherein at least (a) 1-10 mol% of the dicarboxylic acid constitutional unit is a dicarboxylic acid unit having a cyclic acetal backbone, or (b) 1-10 mol% of the diol constitutional unit is a diol unit having the cyclic acetal backbone. The polyester resin has physical properties in which (1) the intrinsic viscosity as measured at 25°C in a mixed solvent containing phenol and 1,1,2,2- tetrachloroethane in a mass ratio of 6:4 is 0.3-1.5 dl/g, and (2) the minimum value of semi-crystallization time based on a depolarization strength method when melted at 280°C and subjected to constant temperature crystallization at 150-230°C is 300 seconds or less. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pinhole resistance, impact resistance, transparency and heat resistance using a polyester resin having a diol unit having a cyclic acetal skeleton and / or a dicarboxylic acid unit having a cyclic acetal skeleton. The present invention relates to a biaxially stretched film having good properties.

[0002]

2. Description of the Related Art Polyethylene terephthalate (hereinafter PE
A biaxially stretched film obtained from a polyester resin typified by (T may be abbreviated as T) has transparency, mechanical properties,
It is widely used for magnetic tapes, food packaging, etc. because of its good dimensional stability, heat resistance, and chemical resistance.

In recent years, in food packaging applications, particularly high demands have been placed on the packaging film in that the contents look beautiful and the contents do not lose their taste during storage. However, the PET biaxially stretched film is excellent in transparency and gas barrier property, but it is poor in flexibility and pinhole resistance, so that pinholes are formed during transportation, which deteriorates gas barrier property, There was a problem that they sometimes went out.

To improve the pinhole resistance, it has been proposed to copolymerize polyester with a soft segment. Specifically, JP-A-7-330926
The publication discloses a biaxially stretched film obtained from a polyester resin having a low molecular weight of polytetramethylene glycol, terephthalic acid and ethylene glycol. Although this biaxially stretched film has improved pinhole resistance, it has a problem of reduced heat resistance. Also,
JP-A-8-41184 proposes a biaxially stretched film obtained from a polyester resin composed of polyoxytetramethylene glycol having a low molecular weight, naphthalenedicarboxylic acid and ethylene glycol. This biaxially stretched film has good pinhole resistance and heat resistance,
There was a problem of impairing transparency. Various studies have been conducted to impart pinhole resistance to a biaxially stretched film obtained from PET or polyethylene naphthalate (hereinafter sometimes abbreviated as PEN), but pinhole resistance, impact resistance, transparency, No biaxially stretched film having heat resistance has been proposed yet.

[0005]

In view of the above problems, the present invention is intended to provide a biaxially stretched film having pinhole resistance, impact resistance, transparency and heat resistance.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, obtained from a polyester resin modified with a dicarboxylic acid having a cyclic acetal skeleton and / or a diol having a cyclic acetal skeleton. It was found that the biaxially stretched film obtained has good pinhole resistance, impact resistance, transparency, and heat resistance, and has reached the present invention.

That is, the present invention provides a polyester resin having a dicarboxylic acid constitutional unit and a diol constitutional unit, wherein at least (a) one of the dicarboxylic acid constitutional units is used.
10 mol% is a dicarboxylic acid unit having a cyclic acetal skeleton, or (b) 1 of the diol constitutional units
The present invention relates to a biaxially stretched film using a polyester resin having the following physical properties (1) and (2) in which 10 mol% is a diol unit having a cyclic acetal skeleton. (1) In a mixed solvent of phenol and 1,1,2,2-tetrachloroethane in a mass ratio of 6: 4, the intrinsic viscosity measured at 25 ° C. is 0.3 to 1.5 dl / g. (2) The minimum value of the half crystallization time based on the depolarization intensity method when melted at 280 ° C. and crystallized at a constant temperature of 150 to 230 ° C. is 300 seconds or less.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The polyester resin used in the biaxially stretched film of the present invention is a dicarboxylic acid structural unit containing 1 to 10 mol% of (A) a dicarboxylic acid unit having a cyclic acetal skeleton (a structural unit derived from a dicarboxylic acid having a cyclic acetal skeleton). A diol structural unit having no cyclic acetal skeleton, (B) a dicarboxylic acid structural unit having no cyclic acetal skeleton and a diol unit having a cyclic acetal skeleton (a structural unit derived from a diol having a cyclic acetal skeleton), A diol structural unit containing 10 mol% or a dicarboxylic acid structural unit containing 1 to 10 mol% of a dicarboxylic acid unit (C) having a cyclic acetal skeleton and a diol structural unit containing 1 to 10 mol% of a diol unit having a cyclic acetal skeleton. It is a polyester resin composed of and.

The diol having a cyclic acetal skeleton constituting the resin used in the biaxially stretched film of the present invention is represented by the general formula (1):

[Chemical 5] Or general formula (2):

[Chemical 6] Compounds represented by are preferred. In the general formulas (1) and (2), R ¹ and R ² each independently have 1 carbon atom.
An organic group selected from the group consisting of an aliphatic group having 10 to 10, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms, preferably a methylene group, an ethylene group, a propylene group. , Butylene group or structural isomers thereof, for example, isopropylene group and isobutylene group. R ³ is an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms,
And an organic group selected from the group consisting of aromatic groups having 6 to 10 carbon atoms, preferably a methyl group, an ethyl group, a propyl group, a butyl group, or a structural isomer thereof, such as an isopropyl group or an isobutyl group. Represent Examples of the compounds represented by the general formulas (1) and (2) include 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, Particularly preferred is 5-methylol-5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -1,3-dioxane and the like.

The dicarboxylic acid having a cyclic acetal skeleton has the general formula (3):

[Chemical 7] Or general formula (4):

[Chemical 8] Compounds represented by are preferred. General formulas (3) and (4)
In the above, R ³ is the same as above, R ⁴ and R ⁵ are each independently an aliphatic group having 1 to 10 carbon atoms, and 3 carbon atoms.
10 to an alicyclic group, and an organic group selected from the group consisting of aromatic groups having 6 to 10 carbon atoms, preferably a methylene group, an ethylene group, a propylene group, a butylene group or structural isomers thereof, for example Represents an isopropylene group and an isobutylene group. R ⁶ and R ⁷ each independently represent a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group, preferably a hydrogen atom or a methyl group. Examples of the compounds represented by the general formulas (3) and (4) include 3,9-bis (1,1-dimethyl-2-carboxyethyl) -2,4,8,10-.
Tetraoxaspiro [5.5] undecane, 5-carboxy-5-ethyl-2- (1,1-dimethyl-2-carboxyethyl) -1,3-dioxane and the like are particularly preferable.

The polyester resin used in the present invention is
By introducing a dicarboxylic acid unit having a cyclic acetal skeleton and / or a diol unit having a cyclic acetal skeleton, pinhole resistance during flexing, impact resistance, transparency and heat resistance can be imparted to the biaxially stretched film.

The content ratio of the diol unit having a cyclic acetal skeleton or the dicarboxylic acid unit having a cyclic acetal skeleton constituting the resin used in the present invention is 1 to 10 of the diol structural unit and the dicarboxylic acid structural unit, respectively.
It is mol%, preferably 3 to 10 mol%. If it is less than 1 mol%, pinhole resistance, impact resistance, and transparency at the time of bending may not be sufficiently obtained, which is not preferable.
If it exceeds mol%, the crystallinity of the resin may not be secured, which is not preferable. The biaxially stretched film obtained by biaxially stretching the polyester resin for a biaxially stretched film produced in the above proportion exhibits good pinhole resistance, impact resistance and transparency when bent.

The diol other than the diol having a cyclic acetal skeleton constituting the resin used in the present invention is not particularly limited, but ethylene glycol, trimethylene glycol, 1,4-butanediol, 1,5
-Aliphatic diols such as pentanediol, 1,6-hexanediol, diethylene glycol, propylene glycol and neopentyl glycol; polyether compounds such as polyethylene glycol, polypropylene glycol and polybutylene glycol; 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,2-decahydronaphthalene dimethanol, 1,
3-decahydronaphthalene dimethanol, 1,4-decahydronaphthalene dimethanol, 1,5-decahydronaphthalene dimethanol, 1,6-decahydronaphthalene dimethanol, 2,7-decahydronaphthalene dimethanol, tetralindi Alicyclic diols such as methanol, norbornene dimethanol, tricyclodecane dimethanol, pentacyclododecan dimethanol; 4,4'-
(1-methylethylidene) bisphenol, methylene bisphenol (bisphenol F), 4,4′-cyclohexylidene bisphenol (bisphenol Z),
Bisphenols such as 4,4′-sulfonylbisphenol (bisphenol S); alkylene oxide adducts of the bisphenols; hydroquinone, resorcin,
Examples thereof include aromatic dihydroxy compounds such as 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenyl ether, and 4,4′-dihydroxydiphenylbenzophenone; and alkylene oxide adducts of the aromatic dihydroxy compounds. Ethylene glycol is particularly preferred from the viewpoints of mechanical performance, economy, etc. of the biaxially stretched film of the present invention. The above effect becomes more remarkable by setting the ratio of the ethylene glycol unit in the diol constitutional unit to preferably 80 to 99 mol%, more preferably 90 to 99 mol%.

The dicarboxylic acid other than the dicarboxylic acid having a cyclic acetal skeleton constituting the resin used in the present invention is not particularly limited, but succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid are used. , Sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, cyclohexanedicarboxylic acid, norbornanedicarboxylic acid, tricyclodecanedicarboxylic acid, pentacyclododecanedicarboxylic acid and other aliphatic dicarboxylic acids and their ester-forming derivatives; terephthalic acid, isophthalic acid , Phthalic acid, 2-methylterephthalic acid, 1,
4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-
Examples thereof include aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and tetralindicarboxylic acid, and ester-forming derivatives thereof. From the viewpoint of mechanical performance of the biaxially stretched film of the present invention, aromatic dicarboxylic acid and its ester-forming derivative are preferable, and from the viewpoint of economy, terephthalic acid and its ester-forming derivative are particularly preferable. From the viewpoint of heat resistance, 2,6-naphthalenedicarboxylic acid and its ester-forming derivative are preferable.
The proportion of aromatic dicarboxylic acid units in the dicarboxylic acid constitutional unit is preferably 80 mol% or more, more preferably 90 mol% or more. By setting the above ratio,
The biaxially stretched film of the present invention has more excellent heat resistance and mechanical performance.

The polyester resin used in the present invention is
The minimum value of the half crystallization time based on the depolarization intensity method when melted at 280 ° C. and crystallized at a constant temperature of 150 to 230 ° C. is 30.
It is 0 seconds or less. When the semi-crystallization time exceeds 300 seconds, the crystallinity becomes small, and when heat-fixing the biaxially stretched film, spherulites become large, which may impair the transparency or make heat-setting impossible. Not preferable.

The intrinsic viscosity of the polyester resin used in the present invention (measured at 25 ° C. in a mixed solvent of phenol and 1,1,2,2-tetrachloroethane in a mass ratio of 6: 4) is preferably 0.3 to. The range is 1.5 dl / g, more preferably 0.5 to 1.3 dl / g, and further preferably 0.6 to 1.1 dl / g. Within the above range, strength and good moldability can be imparted to the biaxially stretched film.

The polyester resin used in the present invention may contain monoalcohols such as butyl alcohol, hexyl alcohol and octyl alcohol, and trivalent or higher polyhydric alcohols such as trimethylolpropane, glycerin and pentaerythritol as long as the object of the present invention is not impaired. Monocarboxylic acids such as polyhydric alcohols, benzoic acid, propionic acid and butyric acid can also be used as raw material monomers.

Further, various molding auxiliaries and additives such as fillers, colorants, reinforcing agents, surface smoothing agents, leveling agents, curing reaction accelerators, light stabilizers, ultraviolet absorbers, plasticizers, Antioxidants, extenders, matting agents, drying regulators, antistatic agents, antisettling agents, surfactants, flow improvers, drying oils, waxes, thermoplastic oligomers and the like may also be included.

The method for producing the polyester resin used in the present invention is not particularly limited, and conventionally known methods can be applied. For example, a melt polymerization method such as a transesterification method and a direct esterification method, or a solution polymerization method can be mentioned. The transesterification catalyst, the esterification catalyst, the etherification inhibitor, the polymerization catalyst used for the polymerization, the various stabilizers such as the heat stabilizer and the light stabilizer, and the polymerization regulator may be those conventionally known. As a transesterification catalyst, compounds such as manganese, cobalt, zinc, titanium, calcium,
Examples of esterification catalysts include compounds such as manganese, cobalt, zinc, titanium and calcium, and examples of etherification inhibitors include amine compounds. Examples of the polycondensation catalyst include compounds such as germanium, antimony, tin and titanium. It is also effective to add various phosphorus compounds such as phosphoric acid, phosphorous acid and phenylphosphonic acid as heat stabilizers. Other light stabilizers, antistatic agents, lubricants,
You may add antioxidant, a mold release agent, etc. Further, in the direct esterification method, water may be added to improve the slurry property.

The method for obtaining the biaxially stretched film from the polyester resin used in the present invention is not particularly limited, but the film is formed by a known method such as extrusion molding or calender molding, and the film is formed in one direction. 1 to 7 times, preferably 2 to 6 times, particularly preferably 2.5 to 5 times, and 1.1 to 7 times, preferably 2 to 5 times in the direction perpendicular to the direction.
It is stretched 6 times, particularly preferably 2.5 to 5 times. As the stretching means for the film, roll stretching, long gap stretching, tenter stretching, or the like can be applied, and the shape at the time of stretching can also be flat, tubular, or the like. Furthermore, sequential biaxial stretching, simultaneous biaxial stretching, uniaxial stretching, or a combination of these is performed. Heat setting in these stretching is performed by passing a heating zone of 30 to 240 ° C. for 1 to 30 seconds.

The thickness of the biaxially stretched film of the present invention is preferably 5 to 300 μm, more preferably 7 to 100 μm,
More preferably, it is 10 to 50 μm.

The number of pinholes after bending the biaxially stretched film of the present invention 500 times is 2.0 / m ² or less, preferably 1.0 / m ² or less. If the number of pinholes after bending 500 times exceeds 2.0 / m ² , pinholes are likely to be formed, and the gas barrier properties may be impaired or the mechanical performance may be impaired, which is not preferable.

The impact strength of the biaxially stretched film of the present invention in an impact punching test is 5000 kg · cm / cm or more, preferably 6000 kg · cm / cm or more, more preferably 7000 kg · cm / cm or more. If the impact strength in the impact punching test is less than 5000 kg · cm / cm, the impact strength becomes insufficient and the biaxially stretched film may be broken, which is not preferable.

The biaxially stretched film of the present invention (thickness 15 μm
The haze of m) is 3% or less, preferably 2% or less, more preferably 1% or less. If the haze exceeds 3%, the transparency may be impaired, which is not preferable.

The biaxially stretched film of the present invention is used in boiling water for 3 days.
The shrinkage rate after hot water treatment for 0 minutes is 3% or less, preferably 2% or less, more preferably 1% or less. If the shrinkage ratio exceeds 3%, heat resistance may be insufficient, which is not preferable.

The biaxially stretched film of the present invention has good pinhole resistance, impact resistance, transparency and heat resistance, and is suitable for various packaging films such as foods, films for magnetic recording media, films for capacitors and the like. Can be used.

[0027]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

Examples 1 to 7 and Comparative Examples 1 to 3 (1) Synthesis of Resin Packing column type rectification column, partial condenser, total condenser, cold trap,
A 150-liter (L) polyester production apparatus equipped with a stirring blade, a heating device, and a nitrogen introduction tube was charged with the monomers in the amounts shown in Tables 1 to 3, and manganese acetate tetrahydrate was added to the dicarboxylic acid component in an amount of 0. 03 mol% was added and the temperature was raised under normal pressure and nitrogen atmosphere. The temperature was raised to 200 ° C., and transesterification reaction was performed. The reaction conversion rate of the dicarboxylic acid component is 90 mol%
After the above, 0.02 mol% of antimony trioxide and 0.06 mol% of trimethyl phosphate are added to the dicarboxylic acid component, the temperature is raised and the pressure is gradually reduced, and finally 270
The polycondensation reaction was carried out at ˜300 ° C. and 0.1 kPa or less.
The viscosity of the reaction product gradually increased, and the reaction was terminated at the time when the melt viscosity became appropriate, and a polyester resin was obtained.

(2) Preparation of biaxially stretched film The obtained polyester resin is extruded to form a cylinder temperature of 250 to 280 ° C. and a die temperature of 250 to 280.
℃, roll temperature 75 ~ 80 ℃, thickness of about 0.2m
An unstretched sheet of m was prepared. Next, the unstretched sheet is heated at a temperature of 10 to 20 ° C. higher than the glass transition temperature to obtain 3.6 × 3.
Simultaneously biaxially stretching 6 times, and then 1 at 210-230 ℃
Heat setting treatment was performed for 0 to 30 seconds to obtain a biaxially stretched film having a thickness of 15 μm.

(3) Evaluation of resin-Measurement was carried out at a constant temperature of 25 ° C. using an intrinsic viscosity mixed solvent (mass ratio: phenol / 1,1,2,2-tetrachloroethane = 6/4). -Semi-crystallization time After crushing resin pellets into a sheet, sandwiching them with cover glass and melting at 280 ° C for 3 minutes, put them in a crystallization bath at a predetermined temperature and measure the change with time in depolarization intensity, and measure the temperature. The half-crystallization time at was determined. The temperature of the crystallization bath is 150
The half-crystallization time was measured by changing the temperature up to 230 ° C. at 10 ° C. intervals, and the minimum value was taken as the half-crystallization time of the resin.

(4) Evaluation of biaxially stretched film and pinhole resistance The biaxially stretched film was bent 500 times with Gelbo flex manufactured by Rigaku Kogyo Co., Ltd., and the axial direction of the gelboflex was taken as the measurement direction. The number of pinholes was measured with a pinhole tester (weak current measuring method). 5 times,
The measurement voltage was 1.0 kV. -Impact strength in impact drilling test Measured according to JIS P813 and ASTM D781. A puncture tester manufactured by Toyo Seiki Co., Ltd. was used as a measuring instrument. The number of measurements is 5, and the measurement condition is temperature 2.
It was carried out at 3 ° C. and 50% relative humidity.・ In accordance with haze JIS-K-7105 and ASTM D1003,
The measuring device is a cloudiness value measuring device manufactured by Nippon Denshoku Industries Co., Ltd. (model:
COH-300A) was used. The heat-resistant biaxially stretched film was marked with a size of 5.0 cm × 5.0 cm, put in boiling water for 30 minutes for hot water treatment, and then the interval was measured. The shrinkage rate was calculated by the following formula. Shrinkage rate (%) = (1-interval after hot water treatment / interval before hot water treatment) × 100 These results are shown in Tables 1 to 3.

The abbreviations used in the table have the following meanings. DMT: dimethyl terephthalate NDCM: 2,6-naphthalenedicarboxylate dimethyl SPD: 3,9-bis (1,1-dimethyl-2-carboxyethyl) -2,4,8,10-tetraoxaspiro [5.5 ] Undecane was added to DOD: 5-carboxy-5-ethyl-2- (1,1-
Dimethyl-2-carboxoxyethyl) -1,3-dioxane EG: ethylene glycol SPG: 3,9-bis (1,1-dimethyl-2-hydroxyethyl) 2,4,8,10-tetraoxaspiro [5 .5] Undecane DOG: 5-methylol-5-ethyl-2- (1,1-
Dimethyl-2-hydroxyethyl) -1,3-dioxane

Table 1 Example numbers Example 1 Example 2 Example 3 Example 4 Monomer charge (mol) Dicarboxylic acid component DMT 293.7 304.5 280.4-NDCM ---- 235.9 Diol component EG 484.6 511.6 451.4 389.2 SPG 14.7 6.1 25.2 11.8 Evaluation of polyester resin Tg (° C) 87 85 89 89 125 IV (dl / g) 0.68 0.67 0 .70 0.65 Semi-crystallization time (second) 125 57 247 198 Evaluation of biaxially stretched film Haze (% / 15 μm) 0.3 0.8 0.2 0.3 Impact strength (kg · cm / cm) 7000 6000 7500 9000 Pinhole resistance (pieces / m ² ) 0.3 0.7 0.1 0.5 Shrinkage (TD:%) 0.8 1.2 0.5 0.2 Shrinkage (MD:% ) 1.4 1.8 0.8 0.3

Table 2 Example No. Example 5 Example 6 Example 7 Monomer charge (mol) Dicarboxylic acid component DMT 300.0 297.2 303.7 SPD-14.9-DOD--15.2 Diol component EG 495.0 505.2 516.2 DOG 15.0 --- Evaluation of polyester resin Tg (° C) 85 84 84 IV (dl / g) 0.65 0.69 0.68 Half crystallization time (sec) 78 178 277 Evaluation of biaxially stretched film Haze (% / 15 μm) 0.2 0.5 0.8 Impact strength (kg · cm / cm) 8500 5500 5500 Pinhole resistance (pieces / m ² ) 0.1 0. 8 0.9 Shrinkage (TD:%) 0.4 1.2 0.9 Shrinkage (MD:%) 0.6 1.6 1.3

Table 3 Example number Comparative example 1 Comparative example 2 Comparative example 3 Monomer charge (mol) Dicarboxylic acid component DMT 262.6 312.2-NDCM--248.0 Diol component EG 407.0 530.8 421 1 SPG 39.4-Evaluation of polyester resin Tg (° C) 94 84 124 IV (dl / g) 0.70 0.69 0.68 Semi-crystallization time (sec) 18000 65 440 Evaluation of biaxially stretched film Haze (% / 15 μm) (a) 0.7 0.9 Impact strength (kg · cm / cm) (a) 5500 7500 Pinhole resistance (pieces / m ² ) (a) 9.8 12.7 Shrinkage (TD:%) (a) 1.8 0.1 Shrinkage (MD:%) (a) 2.1 0.2 (a): The film could not be obtained because heat fixation was not possible.

[0036]

The biaxially stretched film obtained from the resin used in the present invention has pinhole resistance, impact resistance, transparency,
It has excellent performances such as heat resistance and the industrial significance of the present invention is great.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shojiro Kuwahara             5-6 Higashi-Hachiman 5-2, Hiratsuka City, Kanagawa Prefecture             Ryogas Chemical Co., Ltd. Hiratsuka Research Center F-term (reference) 4F071 AA44X AA45X AA46X AE05                       AF23Y AF53 AF54Y AF61Y                       AH04 BA01 BB04 BB06 BB07                       BB08 BB09 BC01 BC17                 4J029 AA03 AC01 AC02 AD01 AD10                       AE03 BA02 BA03 BA05 BA08                       BA10 BB04A BB05A BB12A                       BB13A BC04A BC05A BD00                       BD07A BD09A BD10 BE05A                       BF09 BF24 BF25 BF30 BH02                       CA02 CA04 CA05 CB06A                       CB06B CB10A CC03A CC05A                       CD03 CD07 CF19 DB13 HA01                       HB01 JB171 JC023 JC581                       JE181 JF141 JF181 JF251                       JF321 JF371 JF471 JF541                       JF571

Claims (10)

[Claims] 1. A polyester resin having a dicarboxylic acid constitutional unit and a diol constitutional unit, at least:
(A) 1 to 10 mol% of the dicarboxylic acid constituent unit is a dicarboxylic acid unit having a cyclic acetal skeleton,
Alternatively, (b) a biaxially stretched film comprising a polyester resin having the following physical properties (1) and (2), wherein 1 to 10 mol% of the diol constituent unit is a diol unit having a cyclic acetal skeleton. (1) In a mixed solvent of phenol and 1,1,2,2-tetrachloroethane in a mass ratio of 6: 4, the intrinsic viscosity measured at 25 ° C. is 0.3 to 1.5 dl / g. (2) The minimum value of the half crystallization time based on the depolarization intensity method when melted at 280 ° C. and crystallized at a constant temperature of 150 to 230 ° C. is 300 seconds or less. 2. A diol having a cyclic acetal skeleton is represented by the general formula (1): (In the formula, R ¹ and R ² are each independently a carbon number of 1
Represents an organic group selected from the group consisting of an aliphatic group having 10 to 10, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms. ) Or general formula (2): (In the formula, R ¹ is the same as above, and R ³ has 1 to 1 carbon atoms.
It represents an organic group selected from the group consisting of an aliphatic group having 0, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms. ] The biaxially stretched film of Claim 1 represented by these. 3. A dicarboxylic acid having a cyclic acetal skeleton is represented by the general formula (3): (In the formula, R ⁴ and R ⁵ each independently have a carbon number of 1 to
Represents an organic group selected from the group consisting of an aliphatic group having 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms, and R ⁶ and R ⁷ are each independently Hydrogen atom,
It represents a methyl group, an ethyl group, or an isopropyl group. ) Or general formula (4): (In the formula, R ³ , R ⁴ , R ⁶ and R ⁷ are the same as above.)
The biaxially stretched film according to claim 1, which is represented by: 4. A diol having a cyclic acetal skeleton is 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.
5] Undecane or 5-methylol-5-ethyl-
2- (1,1-dimethyl-2-hydroxyethyl) 1,
The biaxially stretched film according to any one of claims 1 to 3, which is 3-dioxane. 5. The dicarboxylic acid having a cyclic acetal skeleton is 3,9-bis (1,1-dimethyl-2-carboxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, or The biaxially stretched film according to claim 1, which is 5-carboxy-5-ethyl-2- (1,1-dimethyl-2-carboxyethyl) -1,3-dioxane. 6. An aromatic dicarboxylic acid unit accounts for 90 to 100 mol% of the dicarboxylic acid constituent unit.
The biaxially stretched film according to any one of 1. 7. A dicarboxylic acid constitutional unit comprising 90 to 100 mol% of a constitutional unit derived from dimethyl terephthalate and / or its ester-forming derivative.
The biaxially stretched film according to any one of 1. 8. 90 to 100 mol% of the dicarboxylic acid constituent unit is dimethyl 2,6-naphthalenedicarboxylate and / or
The biaxially stretched film according to claim 1, which is a structural unit derived from an ester-forming derivative thereof. 9. The biaxially stretched film according to claim 1, having the following physical properties (1) to (4). (1) The number of pinholes after the bending test is 2.0 / m2 or less. (2) Impact strength in impact drilling test is 5000 kg · c
m / cm or more. (3) The haze of a film having a thickness of 15 μm is 3% or less. (4) Shrinkage rate after hot water treatment for 30 minutes in boiling water is 3
%Less than. 10. A polyester resin having a dicarboxylic acid constitutional unit and a diol constitutional unit, which is at least (a) 1 to 10 mol% of the dicarboxylic acid constitutional unit.
Is a dicarboxylic acid having a cyclic acetal skeleton,
Alternatively, (b) a polyester resin for a biaxially stretched film having the following physical properties (1) and (2), wherein 1 to 10 mol% of the diol constituent unit is a diol unit having a cyclic acetal skeleton. (1) In a mixed solvent of phenol and 1,1,2,2-tetrachloroethane in a mass ratio of 6: 4, the intrinsic viscosity measured at 25 ° C. is 0.3 to 1.5 dl / g. (2) The minimum value of the half crystallization time based on the depolarization intensity method when melted at 280 ° C. and crystallized at a constant temperature of 150 to 230 ° C. is 300 seconds or less.