JP2005097426A - Highly moisture-permeable polyester film and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly moisture-permeable polyester elastomer film which is excellent in water resistance and surface smoothness and of which the edge shaking and width variation of a molten resin film are small even when the film is formed at a high speed. <P>SOLUTION: A molten resin film composed of a polyester elastomer prepared from an acid component mainly comprising an aromatic dicarboxylic acid and a glycol component being polyether glycol and an olefin resin, in a ratio (by wt.%) of the polyester elastomer to the olefin resin of 75/25-99/1, is solidified with a cooling roll to give the highly moisture-permeable polyester film. The surface roughness (Ra) of this polyester film is 0.1 μm or lower, and the functional group concentration in the above olefin resin is 200-2,000 equivalents/ton. The method for producing the polyester film comprises casting the above molten resin film onto a cooling roll with surface roughness (Ra) of 0.2-10 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polyester film having a high moisture permeability despite its low hygroscopicity, and a laminate thereof. More specifically, the present invention relates to a highly moisture-permeable polyester film suitable for use in sanitary materials, clothing materials, agriculture, building materials, etc. that are water-resistant, waterproof, and highly moisture-permeable, and a method for producing the same. is there.

  Conventionally, as a highly moisture-permeable polyester film, a thermoplastic elastomer film having an aromatic polyester unit as a hard segment and a polyether glycol unit obtained by copolymerizing two or more different alkylene oxide units as a soft segment has been disclosed. However, when the thermoplastic elastomer is melted and then extruded into a layer from a T-die to produce a single film of the thermoplastic elastomer, or when a laminate is produced by extrusion lamination onto a substrate such as a nonwoven fabric or a plastic sheet, it is melted. There is a drawback that the resin film tends to be distorted and / or varies in width and can only be manufactured at a low speed (see, for example, Patent Document 1).

In order to solve such drawbacks, a composite sheet is disclosed in which a mixture of a polyester elastomer containing a polypropylene resin and / or a polyethylene resin is extruded and laminated on a nonwoven fabric (see, for example, Patent Document 2). However, when the mixture is melted and extruded from a T-die in a layered manner, the effect of reducing the fluctuation of the melted resin film and / or width fluctuation is small (if the melt-extruding conditions are optimized, the molten resin film exceeds 30 m / min. In addition, there is a significant decrease in moisture permeability due to the blending of polypropylene resin and / or polyethylene resin, and polyester film formation at low speed (for example, 25 m / min) When a film is formed using a known chrome-plated mirror roll, the film surface in contact with the roll is likely to have a dent exceeding 50 μm (the appearance of the resulting film is poor), and the commercial value is reduced. In particular, it has not been satisfactory for the recent demand for a highly moisture-permeable film having a good appearance and a method for producing the film.
JP 2001-172411 A JP-A-9-277462

  Conventionally, it is intended to obtain a polyester elastomer film, which has been difficult to produce stably, at a low cost. Even if the film is formed at a high speed exceeding 30 m / min, the earring and width of the molten resin film It is an object of the present invention to provide a polyester film having a water resistance and a waterproof property while being able to reduce fluctuation and having a high moisture permeability, and a method for producing the same.

That is, the present invention employs the following configuration.
1. A molten resin film obtained by melt-mixing an acid component mainly composed of an aromatic dicarboxylic acid and a polyester elastomer having a polyether glycol component as a glycol component and an olefin resin at a ratio of 75/25 to 99/1 (% by weight). The polyester film has a surface roughness (Ra) of 0.1 μm or less, and the functional group concentration in the olefin resin is 200 to 2000 equivalents. A highly moisture-permeable polyester film characterized by being / ton.
2. 2. The highly moisture-permeable polyester film according to the first aspect, wherein the polyether elastomer polyether glycol is a random copolymer polyether glycol.
3. A copolymer comprising, as a main constituent unit, the olefin-based resin comprising at least one or more α-olefin having 2 to 6 carbon atoms and an ethylene bond-forming α, β-unsaturated carboxylic acid or an ester-forming derivative thereof; or The highly moisture-permeable polyester film according to the first or second invention, which is a mixture with another polymer containing the polymer.
4). The olefin-based resin is (A) a polymer having at least one or more kinds of α-olefins having 2 to 6 carbon atoms as a main structural unit, and (B) at least one or more kinds of α-olefins having 2 to 6 carbon atoms; The highly moisture-permeable polyester according to any one of the first to third inventions, comprising a copolymer having a main structural unit of an ethylene bond-forming α, β-unsaturated carboxylic acid or an ester-forming derivative thereof. Film.
5). The high moisture permeability according to any one of the first to fourth inventions, wherein the olefin resin is finely dispersed in a polyester film, and an average diameter of dispersed particles is 0.2 to 8 μm. Polyester film.
6). A melt mixture of an acid component mainly composed of an aromatic dicarboxylic acid, a polyester elastomer whose glycol component is glycol and polyether glycol, and an olefin resin in a ratio of 75/25 to 99/1 (% by weight) in a melt extruder. Then, the mixture is cast from a melt extruder on a cooling roll having a surface roughness (Ra) of 0.2 to 10 μm to be cooled and solidified to form a film. The surface roughness (Ra) of the film Is made into 0.1 micrometer or less, The manufacturing method of the highly moisture-permeable polyester-type film characterized by the above-mentioned.
7). The olefin resin according to the sixth invention comprises at least one or more kinds of α-olefin having 2 to 6 carbon atoms and an ethylene bond-forming α, β-unsaturated carboxylic acid or an ester-forming derivative thereof as main structural units. A method for producing a highly moisture-permeable polyester-based film, characterized in that the copolymer is a copolymer with another polymer or a mixture with another polymer containing the copolymer.
8). The olefin resin according to the sixth invention is (A) a polymer having at least one or more kinds of α-olefin having 2 to 6 carbon atoms as a main structural unit, and (B) at least one or more kinds of carbon atoms having 2 to 2 carbon atoms. 6. A method for producing a highly moisture-permeable polyester film, comprising a copolymer mainly comprising an α-olefin of 6 and an ethylene bond-forming α, β-unsaturated carboxylic acid or an ester-forming derivative thereof.

  The polyester-based film of the present invention is a polyester-based film excellent in surface smoothness of a polyester elastomer, and has both antimony performance such as high moisture permeability, water resistance and waterproofness. Moreover, even if the film is formed at a high speed exceeding 30 m / min, the melted resin film has a small ear fluctuation and width fluctuation and can be stably formed, so that it is an economical polyester elastomer film.

Hereinafter, the present invention will be described in detail.
The polyester elastomer constituting the polyester film of the present invention has an acid component mainly composed of aromatic dicarboxylic acid and a polyether glycol component as a glycol component.
As the aromatic dicarboxylic acid component, one or more selected from terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, diphenylsulfone dicarboxylic acid, 5-sodium sulfoisophthalic acid and the like can be used. Of these, terephthalic acid and / or naphthalenedicarboxylic acid are preferred. The aromatic dicarboxylic acid is preferably 70 mol% or more of the total acid component from the viewpoint of maintaining the thermal stability of the polyester elastomer. Other acid components include oxalic acid, succinic acid, adipic acid, sebacic acid, decanedicarboxylic acid, aliphatic dicarboxylic acid such as maleic acid, fumaric acid and dimer acid, oxycarboxylic acid such as p-oxybenzoic acid, and cyclohexanedicarboxylic acid. An alicyclic dicarboxylic acid such as an acid can be used, but the amount is preferably less than 30 mol%. If the dicarboxylic acid other than the aromatic dicarboxylic acid exceeds 30 mol%, the thermal stability of the polyester elastomer is deteriorated.

  As glycol components, ethylene glycol, propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl An aromatic glycol such as an aliphatic glycol such as glycol, an alicyclic glycol such as cyclohexanedimethanol, an ethylene oxide adduct of bisphenol A, and an ethylene oxide adduct of bisphenol S can be used. Of these, ethylene glycol and / or 1,4-butanediol are preferred.

In addition, as the polyether glycol component, a polyether glycol component having a molecular weight of 2000 to 4000 composed of repeating one or more alkylene units having 2 to 10 carbon atoms is preferable. As the polyether glycol component, an ethylene oxide component, a tetramethylene oxide component, and a polytetramethylene oxide component can be used. When the molecular weight of the polyether glycol is less than 2000, a polyester elastomer having sufficient flexibility and moldability may not be obtained. On the other hand, when the molecular weight exceeds 4000, phase separation tends to occur during polymer synthesis, and a polyester elastomer may not be obtained.
The polyether glycol component can be a block copolymer polyether glycol or a random copolymer polyether glycol, but it is preferable to use a random copolymer polyether glycol in order to obtain a low water-absorbing polyester film.

With the random copolymer polyether glycol, a polyester elastomer having a low water absorption rate can be obtained even if an ethylene oxide component is used. The ethylene oxide component contained in the random copolymer polyether glycol is preferably 80 to 40 mol%. When an ethylene oxide component exceeds 80 mol%, a water absorption rate becomes high and when the use of a highly moisture-permeable film requires hydrophobicity, it may become unusable. On the contrary, when it is less than 40 mol%, the moisture permeability becomes low, which is not preferable as a highly moisture permeable film.
It is preferable that substantially both ends of the random copolymer polyether glycol are hydroxyl groups derived from ethylene oxide. In the case where the terminal is a hydroxyl group derived from tetramethylene oxide and / or polytetramethylene oxide, tetrahydrofuran is generated by a ring-opening reaction, which is not preferable because a by-product and / or an odor is generated.

  In the random copolymer polyester elastomer, soft segment components other than the random copolymer polyether glycol may be copolymerized as necessary. As such a soft segment component, a polyether glycol such as polyethylene oxide glycol, polypropylene oxide glycol, polytetramethylene oxide glycol or the like having a molecular weight of 400 to 6000, or an aliphatic dicarboxylic acid having 2 to 12 carbon atoms and an aliphatic having 2 to 12 carbon atoms. Polyesters composed of glycols such as polyethylene adipate, polytetramethylene adipate, polyethylene sebacate, polyneopentyl sebacate, polytetramethylene dodecanate, polytetramethylene azate, polyhexamethylene azate, poly-ε-caprolactone, etc. It is done.

  When the total amount of the soft segment components of the polyester elastomer constituting the polyester film of the present invention is 70 to 95% by weight of the total polymer, the obtained polyester film retains excellent moisture permeability and has a water absorption rate. Since it becomes low, it is preferable. When the total amount of the soft segment components is less than 70% by weight, the moisture permeability of the obtained polyester film may be lowered. On the other hand, when it exceeds 95% by weight, the moldability may be reduced due to the decrease in crystallinity of the polyester elastomer, and the high-speed film forming property may be lost.

  In the polyester elastomer constituting the polyester film of the present invention, a trifunctional or higher polycarboxylic acid such as trimellitic anhydride, benzophenonetetracarboxylic acid, pyromellitic anhydride and / or a trifunctional or higher polyol such as trimethylpropane and glycerin is used. Can be contained in a small amount. The total amount of the tri- or higher functional polycarboxylic acid and / or polyol is preferably 5 mol% or less of the total carboxylic acid component and / or the total polyol component, from the viewpoint of maintaining the thermal stability of the polyester elastomer.

  As a substitute measure of the average molecular weight of the polyester elastomer constituting the polyester film of the present invention, the reduced viscosity is preferably 1.0 to 4.0. When the reduced viscosity is less than 1.0, the mechanical properties of the obtained polyester film may be inferior. On the other hand, when it exceeds 4.0, the fluidity when the mixture of the polyester elastomer and the olefin resin is melted is deteriorated, and the film forming property may be lowered.

  The polyester elastomer constituting the polyester film of the present invention can be produced by a known method. For example, it can be produced by either a transesterification method or a direct polymerization method. Further, it may be produced by a solid phase polymerization method in order to increase the molecular weight. Further, the chain may be extended with an isocyanate compound, an epoxy compound or the like after polymerization of the polyester.

  In the production of the polyester elastomer constituting the polyester film of the present invention, antimony oxide, germanium oxide, a titanium compound, or the like can be used as a polymerization catalyst. In particular, tetraalkyl titanates such as tetrabutyl titanate and tetramethyl titanate or oxalic acid metal salts such as titanium potassium oxalate are preferable. As other catalysts, tin compounds such as dibutyltin oxide and dibutyltin laurate, and lead compounds such as lead acetate can also be used.

  The polyester elastomer constituting the polyester film of the present invention includes an antioxidant, a heat stabilizer, an ultraviolet absorber, a plasticizer, a pigment, an antistatic agent, a lubricant, a crystal nucleating agent, inorganic or organic particles as necessary. You may mix | blend the lubricant which consists of. As a method for blending these additives, they can be blended using a kneader such as a heating roll, a Banbury mixer, or an extruder. Moreover, you may add and mix in the oligomer before the transesterification reaction or polycondensation reaction at the time of manufacturing a polyester elastomer.

  The olefin resin constituting the polyester film of the present invention is preferably polyethylene and / or ethylene copolymer. For example, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ultra high molecular weight polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer, Ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer Polymers, ionomers, ethylene-maleic anhydride graft copolymers, ethylene-vinyl alcohol copolymers, and the like can be used. Moreover, the 1 type (s) or 2 or more types selected from the above can be used as an olefin resin.

  In the polyester film of the present invention, the mixing ratio of the polyester elastomer and the olefin resin is 75/25 to 99/1 (% by weight) to suppress the earring and / or width variation of the molten resin film, and to increase the transparency. Necessary from the viewpoint of maintaining wetness. When the olefin-based resin is less than 1% by mass, the effect of suppressing the fluctuation of the molten resin film and / or the fluctuation of the width when the mixture is melted and extruded from the T die in layers is not preferable. Conversely, when the olefin resin exceeds 25% by weight, the moisture permeability of the obtained polyester film is lowered, which is not preferable.

  The olefin resin constituting the polyester film of the present invention contains a functional group, and the functional group concentration is in the range of 200 to 2000 equivalent / ton (molar equivalent of the functional group present in 1 ton of mass of the entire olefin polymer). It is necessary to be. When the functional group concentration is in the above range, the affinity of the olefin resin to the polyester elastomer is increased moderately, and the molecular chains of the olefin resin and polyester chemically interact with each other, so that the melt of the molten resin film is shaken. And / or width variation can be suppressed and the high moisture permeability of the obtained polyester-type film can be hold | maintained. When the functional group concentration in the olefin-based resin is less than 200 equivalents / ton, when the mixture is melted and extruded from the T die in a layered form, the effect of suppressing the earring and / or width fluctuation of the molten resin film tends to be small. On the contrary, when the functional group concentration exceeds 2000 equivalents / ton, not only the ear shaking and / or width fluctuation suppressing effect of the molten resin film is saturated, but also the thermal stability of the mixture of the polyester elastomer and the olefin resin is lowered. Sometimes.

  Examples of the olefin resin containing a functional group mentioned here include a copolymer of an olefin and a functional group-containing vinyl monomer. Preferable functional groups include functional groups that are polar and have an effect of increasing affinity with the polyester resin. Examples thereof include a carboxyl group, a glycidyl group, and an acid anhydride group. Specific examples include ethylene-α, β-unsaturated carboxylic acid copolymers such as ethylene- (meth) acrylate copolymers and ethylene- (meth) acrylic acid ester copolymers produced by various production methods and catalysts. It is done. However, some or all of the carboxylic acid groups of the α, β-unsaturated carboxylic acid were neutralized with metal ions such as Na, K, Li, Zn, Mg, and Ca as a copolymer of vinyl monomers having functional groups. In the case of using an ionomer, it is preferable that the total amount of metal ions does not exceed 200 ppm with respect to the total amount of the olefin-based polymer because foreign matters having metal particles as a core are easily generated in the melt-extrusion process.

  In the polyester film of the present invention, the olefin resin mixed in the polyester is finely dispersed in the form of particles, and the average diameter of the dispersed particles is preferably 0.2 to 8 μm, more preferably 0.2 to It is 4 μm, more preferably 0.4 to 2 μm. When the average diameter of the dispersed particles is in the above range, the interaction between the olefin resin and the polyester elastomer suppresses the fluctuation of the melted resin film and / or width variation, and maintains the high moisture permeability of the obtained polyester film. it can. When the dispersed particle diameter of the olefin-based resin is less than 0.2 μm, there is a tendency that the effect of suppressing the fluctuation of the melted resin film and / or the fluctuation of the width when the mixture is melted and extruded from the T die in layers. On the other hand, when the thickness exceeds 8 μm, there may be no effect of suppressing the fluctuation of the melted resin film and / or the fluctuation of the width, and the moisture permeability of the obtained polyester film may be lowered.

  As a selection example of the olefin resin for finely dispersing the olefin resin in the above range, there is a combined use of an olefin resin not containing a functional group and an olefin resin containing a functional group. Specific examples include the combined use of polyethylene and ethylene- (meth) acrylic acid copolymer, and the combined use of ethylene-α-olefin copolymer and ethylene-α-olefin- (meth) acrylic acid copolymer.

  In addition, in order to obtain the intended effect of the present invention, as an example of a more preferable olefin resin, an olefin resin containing a monomer component capable of forming a crosslinked structure and / or a branched structure in an amount of less than 5% by weight is used. Resin. Examples of the monomer include unsaturated monomers having two or more addition polymerizable reactive groups. Examples of the crosslinkable monomer include butylene diacrylate, butylene dimethacrylate, trimethylolpropane trimethacrylate, divinylbenzene, trivinylbenzene, vinyl acrylate, vinyl methacrylate and the like. Of these, butylene diacrylate and butylene dimethacrylate are preferred. Examples of the graft-bonding monomer include allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, monoallyl maleate, monoallyl fumarate, monoallyl itaconate, and the like. Of these, allyl methacrylate and diallyl methacrylate are preferred.

In order to obtain the desired effect of the polyester film of the present invention, a resin satisfying the following formula (I) is given as an example of selection of a suitable olefin resin.
0.15 ≦ (Mi−Mf) /m≦1.0 (I)
(In the formula, Mi is the melt flow rate of the polyester elastomer measured at a temperature of the crystalline polyester elastomer + 30 ° C. (MFR, g / 10 minutes). Mf is the polyester elastomer measured at the temperature of the polyester elastomer melting point + 30 ° C.) (MFR of molten mixture of olefin resin (g / 10 min.) M is the content (% by weight) of olefin resin in the mixture.)
The melt flow rate (MFR) here is measured by a method specified in JIS K7210 using a melt index measuring device (MELT INDEXER, manufactured by Toyo Seiki Co., Ltd.) under conditions of an orifice diameter of 2.09 mm and a load of 2.16 kgf. It is a value showing the melting characteristics, and by setting the type and amount of the olefin resin so that this value falls within the specific range shown in the above formula, the excellent effect of the polyester film of the present invention is realized. .

  In the polyester film of the present invention, a polymer obtained by dry blending or melt-mixing a polyester elastomer and an olefin resin is melted in a known single-screw or twin-screw extruder, and then melted in layers using a T die. A resin film is obtained.

  In the present invention, after the polyester is melted in a known single or twin screw extruder, the molten resin film extruded in a layer form from a T die is solidified by a cooling roll having a surface roughness (Ra) of 0.2 to 10 μm. is required. In addition, the surface shape of the cooling roll can be a spiral groove, a diamond cut groove, a satin finish, etc. Of these, the surface has a satin finish A roll is particularly preferred.

When the surface roughness is less than 0.2 μm, when the molten resin film is cooled and solidified, numerous recesses exceeding 50 μm are generated on the film surface in contact with the cooling roll, and the commercial value of the obtained polyester film is lowered. In this case, the commercial value is unfavorable.
When the molten resin film is cooled and solidified, numerous concave portions exceeding 50 μm are generated on the film surface in contact with the cooling roll. Conversely, when the roll surface roughness exceeds 10 μm, the satin pattern is transferred to the film. Not only the laminating property of the film and the fibrous base material is deteriorated, but also the commercial value is lowered because the appearance of the obtained laminate is deteriorated.
At this time, the roll surface roughness (Ra) is preferably 0.2 to 3.5 μm, and more preferably 0.2 to 2.5 μm.

  In the present invention, the surface roughness (Ra) of the polyester film is required to be 0.1 μm or less in order to ensure laminating properties with the fibrous base material, but the surface roughness (Ra) is 0.02. It is more preferable that the thickness is ˜0.1 μm from the viewpoint of securing the laminate property with other materials and reducing the blocking of the film after storage.

  In the present invention, when the molten resin film is brought into contact with the cooling roll, it is preferable to employ a method of forcibly blowing air or a method of closely adhering with static electricity. Moreover, both the forced air spraying method and the electrostatic contact method are more preferable to carry out the method in which both end portions and the central portion of the layered resin are made independent. Furthermore, when the molten resin contacts the cooling roll, it is more preferable to use a measure (for example, a device such as a vacuum chamber or a vacuum box) for reducing the accompanying flow by reducing the pressure on the opposite side.

  In the present invention, after cooling and solidifying, both ends are cut and removed as necessary to obtain a polyester film. In addition, it is possible to reuse the polymer obtained by cutting and removing both ends before winding after cooling and solidification, and then squeezing or heat-melting the polymer. The reuse rate is not particularly limited, but is preferably 5 to 60% by weight. Moreover, you may give a corona discharge process to a polyester-type film before winding after cooling solidification.

The moisture permeability of the polyester film of the present invention is determined according to the calcium chloride method of JIS Z0208, and is preferably 4000 g / m ² · day, more preferably 5000 to 10000 g / m ² · day. Degree. Higher moisture permeability of the film is preferred, but if it is too high, the water resistance and waterproofness of the film will be inferior, so the upper limit is about 10,000 g / m ² · day.

  The thickness of the polyester film of the present invention is a characteristic that directly affects moisture permeability, but is preferably 0.5 to 500 μm, more preferably 5 to 100 μm, and most preferably 10 to 50 μm. If the thickness of the polyester film is less than 0.5 μm, pinholes are likely to occur, which is not preferable. On the other hand, when it exceeds 500 μm, it is not preferable because sufficient moisture permeability may not be obtained.

Hereinafter, the present invention will be described in more detail based on examples.
[Evaluation methods]
(1) Reduced viscosity of polyester elastomer 0.05 g of polyester elastomer was dissolved in a mixed solvent (phenol / tetrachloroethane = 60/40 (volume%)), and measured at 30 ° C. using an Ostwald viscometer.

(2) Functional group concentration of olefin resin The olefin polymer was dissolved in a mixed solvent of chloroform-d / trifluoroacetic acid, and the molecular structure and functional group concentration (mol%) of the olefin resin were determined by H-NMR spectrum analysis. This was converted into mass, and the content (equivalent) of the functional group per ton of olefin resin was calculated.

(3) Average dispersion particle size of olefin resin in polyester film Ultrathin by cutting a polyester film embedded in an epoxy resin and curing it with a cryomicrotome in a cross section parallel to each stretching direction Sections were prepared. This was dyed with ruthenium oxide, held at room temperature for 10 minutes, then carbon-deposited and observed with a transmission electron microscope. The average diameter of the dispersed particles was determined by a weighted average of the long diameters using an image analysis apparatus (Toyobo Co., Ltd., V10).

(4) Cooling roll surface roughness (Ra)
It measured according to JIS B0601 (1982).
(5) Polyester film surface roughness (Ra)
The film cut out to 10 cm × 10 cm was visually observed, and the film surface that was in contact with the cooling roll at the time of casting had no dent exceeding 50 μm and was evaluated by the following method as having an evaluation value. In addition, it was set as the surface roughness (Ra) with the average value of 20 times measurement.
a. Measuring device: ET-30HK manufactured by Kosaka Laboratory
b. Palpation tip radius: 0.5 μm
c. Palpation load: 5mg
d. Measurement length: 1mm
e. Cut-off value: 0.08mm

(6) Stability of molten resin film (surging)
After the mixture of the polyester elastomer and the olefin resin was melted, the width variation of the molten resin film and the stability of the end (ear fluctuation) when extruded in a layer form using a T-die were evaluated. In the case where the width of the resin film was stable and there was no fluctuation of the ears (in the case of ○), it was evaluated as practical.
○: Good ×: Both ends vigorously fluctuate, and the width of the molten resin film fluctuates.

(7) Moisture permeability of polyester film The obtained polyester film was measured under 40 degreeC and 90% RH based on the calcium chloride method of JISZ0208.

[Production method of polyester elastomer]
197 parts by weight of dimethyl terephthalate, a random copolymer of tetramethylene oxide and ethylene oxide (trade name, manufactured by Nippon Oil & Fats Co., Ltd.), equipped with a reactor equipped with an inlet, a thermometer, a pressure gauge, a distillation tube with a rectifying column, and a stirring blade : DC-3000) 1006 parts by weight, phenolic antioxidant (manufactured by Ciba Geigy Japan, trade name: Irganox 1330), 2.4 parts by weight, and 1.2 parts by weight of tetrabutyl titanate were charged and the temperature was raised from room temperature to 200 ° C. The transesterification was performed by warming. Next, the temperature inside the polymerization can was increased while reducing the pressure, and then an initial condensation reaction was performed at 245 ° C. and 1 hPa or less. The polymerization reaction was further carried out at 245 ° C. and 1 hPa or less to obtain a pellet-shaped polyester elastomer (reduced viscosity: 2.53 dl / g).

[Olefin resin mixed with polyester elastomer]
(A) Low density polyethylene [LDPE]: (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikasen G401), functional group amount: 0 equivalent / ton.
(B) Ethylene-acrylic acid copolymer [EAA]: (manufactured by Dow Chemical Company, trade name: Primacol 3440), functional group amount: 1389 equivalents / ton.
(C) Ethylene-ethyl acrylate copolymer [EEA] (manufactured by Mitsui DuPont Polychemical Co., Ltd., trade name: EVAFLEX A712), functional group amount: 1300 equivalent / ton.
(D) Ethylene-methyl acrylate copolymer [EMA]: (Eastman Chemical Company, trade name: EMAC2260), functional group amount: 2790 equivalents / ton.
(E) Ethylene-methacrylic acid copolymer [EMAA] (manufactured by Mitsui DuPont Polychemical Co., Ltd., trade name: Nucrel N1108C), functional group amount: 2246 equivalent / ton.
(F) Styrene-ethylene / butylene-styrene block copolymer [SEBS, S / EB ratio = 30/70] (manufactured by Asahi Kasei Co., Ltd .: Tuftec M1913), functional group amount: 0 equivalent / ton.
(G) Ethylene-1-butene copolymer [EBM]: (manufactured by Nippon Synthetic Rubber Co., Ltd., trade name: EBM2041P), functional group amount: 0 equivalent / ton.
(H) Polypropylene [PP] (manufactured by Sumitomo Chemical Co., Ltd., trade name: Nobrene FS2011DG2), functional group amount: 0 equivalent / ton.

[Example 1]
Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (manufactured by Ciba Geigy Japan, trade name: Irganox 1010) in a mixture of polyester elastomer / EAA = 94/6 (% by weight) ) 0.3 part by weight, dilauryl thiopropionate (product name: Sinox DL) manufactured by Shiraishi Calcium Co., Ltd. 0.3 part by weight, 2- (2′-hydroxy-3 ′, 5′-di-third (Butyl-phenyl) -5-chlorobenzotriazole (trade name: Seethorpe 705, manufactured by Shiraishi Calcium Co., Ltd.) 0.5 parts by weight of the mixture was pre-kneaded at 220 ° C. using a twin-screw vent type extruder to form a pellet A mixture was obtained. Next, the pellet-like mixture heated and dried under vacuum was melted at 220 ° C. using a single screw extruder, and then surfaced under the conditions of an air gap of 2 cm from a T die (lip gap: 0.8 mm, heated to 220 ° C.). Casted in layers to a satin-like cooling roll (circumferential speed 80 m / min, that is, high-speed film-forming speed) with a roughness (Ra) of 1 μm, the distance between the T die and the cooling roll is 2 cm, and the center and both ends are separated Was then electrostatically contacted (applied DC power supply at the center: 4.5 kV, both ends: 6 kV) and solidified by cooling to obtain a polyester film having a thickness of 30 μm.
Note that no surging was observed in the melt-extruded molten resin film from the T-die. Moreover, the moisture permeability of the obtained polyester film was 5400 g / m ² · day, the dispersed particle diameter of the olefin resin was 0.5 μm, and the surface roughness of the film was 1 μm. These results are shown in Table 1.

[Example 2]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a mixture of polyester elastomer / LDPE / EAA = 94/3/3 (% by weight) was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.

[Example 3]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a mixture of polyester elastomer / LDPE / EAA = 88/6/6 (% by weight) was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.

[Example 4]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a mixture of polyester elastomer / LDPE / EAA = 88/9/3 (% by weight) was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.

[Example 5]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a satin-like cooling roll having a surface roughness (Ra) of 0.5 μm was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.
[Example 6]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 2 except that a satin-like cooling roll having a surface roughness (Ra) of 0.5 μm was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.

[Example 7]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a satin-like cooling roll having a surface roughness (Ra) of 3.3 μm was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.
[Example 8]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 2 except that a satin-like cooling roll having a surface roughness (Ra) of 3.3 μm was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.

[Example 9]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 2 except that a mixture of polyester elastomer / EEA = 94/6 (% by weight) was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.

[Example 10]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 2 except that a mixture of polyester elastomer / LDPE / EEA = 94/3/3 (% by weight) was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.

[Example 11]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a mixture of polyester elastomer / LDPE / EMA = 94/3/3 (% by weight) was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.
[Example 12]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a mixture of polyester elastomer / EBM / EAA = 94/3/3 (% by weight) was used.
Table 1 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.

[Comparative Example 1]
Except for using a polyester elastomer alone, an attempt was made to obtain a polyester film in the same manner as in Example 1. However, both ends of the molten resin film were shaken violently, the fluctuation of the width of the molten resin film was large, and stable film formation was not possible. It was. Therefore, a polyester film having a film forming speed of 25 m / min and a thickness of 30 μm was obtained. At a running speed of 25 m / min, both ends of the molten resin film were slightly swayed.
Table 2 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.

[Comparative Example 2]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a mirror-like cooling roll having a surface roughness (Ra) of 0.05 μm or less was used.
Table 2 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.
The obtained polyester film was poor in appearance (having an infinite number of dents of 50 μm or more) and was not preferable as a highly moisture-permeable polyester film.
[Comparative Example 3]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a satin-like cooling roll having a surface roughness (Ra) of 4 μm was used.
Table 2 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.
The resulting polyester film has a poor appearance (the pattern of pear texture spreads in patches)
It was not preferable as a highly moisture-permeable polyester film.

[Comparative Example 4]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a mixture of polyester elastomer / LDPE / EAA = 70/15/15 (wt%) was used.
Table 2 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.
This method was excellent in melt extrudability from a T die at a high speed, but was unpreferable as a highly moisture permeable polyester film because of its low moisture permeability.

[Comparative Example 5]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 2 except that a mirror-like cooling roll having a surface roughness (Ra) of 0.05 μm or less was used.
Table 2 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.
The obtained polyester film was poor in appearance (having an infinite number of dents of 50 μm or more) and was not preferable as a highly moisture-permeable polyester film.
[Comparative Example 6]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 2 except that a satin-like cooling roll having a surface roughness (Ra) of 4 μm was used.
Table 2 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.
The resulting polyester film has a poor appearance (the pattern of pear texture spreads in patches)
It was not preferable as a highly moisture-permeable polyester film.

[Comparative Example 7]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a mixture of polyester elastomer / EMA = 94/6 (% by weight) was used.
Table 2 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.
In the obtained film, a gelled product was occasionally found, which was not preferable as a highly moisture-permeable polyester film.
[Comparative Example 8]
A polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that a mixture of polyester elastomer / SEBS = 94/6 (% by weight) was used.
Table 2 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.
The melt extrudability from the T die at high speed was inferior (both ends of the molten resin film were slightly distorted).

[Comparative Example 9]
An attempt was made in the same manner as in Example 1 except that a mixture of polyester elastomer / PP = 94/6 (% by weight) was used. However, both ends of the molten resin film were shaken vigorously, and the width of the molten resin film was varied. Large and stable film formation was not possible. Therefore, a polyester film having a film forming speed of 25 m / min and a thickness of 30 μm was obtained. At a film forming speed of 25 m / min, both ends of the molten resin film were stable.
Table 2 shows the film-formability of the molten resin film and the evaluation results of the obtained polyester film.

  Conventionally, a polyester elastomer film which has been difficult to stably produce can be produced with excellent surface smoothness, and can be stably produced at high speed, and a highly moisture-permeable polyester elastomer film excellent in economy can be provided. The polyester elastomer film of the present invention has water resistance, waterproofness, and high moisture permeability, so it can be suitably used for hygiene materials, clothing materials, agriculture, building materials, etc. It is.

Claims (8)

  A molten resin film obtained by melt-mixing an acid component mainly composed of an aromatic dicarboxylic acid and a polyester elastomer having a polyether glycol component as a glycol component and an olefin resin at a ratio of 75/25 to 99/1 (% by weight). The polyester film has a surface roughness (Ra) of 0.1 μm or less, and the functional group concentration in the olefin resin is 200 to 2000 equivalents. A highly moisture-permeable polyester film characterized by being / ton.   2. The highly moisture-permeable polyester film according to claim 1, wherein the polyether elastomer polyether glycol is a random copolymer polyether glycol.   A copolymer comprising, as a main constituent unit, the olefin-based resin comprising at least one or more α-olefin having 2 to 6 carbon atoms and an ethylene bond-forming α, β-unsaturated carboxylic acid or an ester-forming derivative thereof; or The highly moisture-permeable polyester film according to claim 1 or 2, which is a mixture with another polymer containing the polymer.   The olefin-based resin is (A) a polymer having at least one or more kinds of α-olefins having 2 to 6 carbon atoms as a main structural unit, and (B) at least one or more kinds of α-olefins having 2 to 6 carbon atoms; The highly moisture-permeable polyester system according to any one of claims 1 to 3, comprising a copolymer mainly comprising an ethylene bond-forming α, β-unsaturated carboxylic acid or an ester-forming derivative thereof. the film.   The highly permeable polyester according to any one of claims 1 to 4, wherein the olefin resin is finely dispersed in a polyester film, and an average diameter of dispersed particles is 0.2 to 8 µm. Film.   A melt mixture of an acid component mainly composed of an aromatic dicarboxylic acid, a polyester elastomer whose glycol component is glycol and polyether glycol, and an olefin resin in a ratio of 75/25 to 99/1 (% by weight) in a melt extruder. Then, the mixture is cast from a melt extruder on a cooling roll having a surface roughness (Ra) of 0.2 to 10 μm to be cooled and solidified to form a film. The surface roughness (Ra) of the film Is made into 0.1 micrometer or less, The manufacturing method of the highly moisture-permeable polyester-type film characterized by the above-mentioned.   The olefin resin according to claim 6 is a co-polymer comprising at least one or more α-olefin having 2 to 6 carbon atoms and an ethylene bond-forming α, β-unsaturated carboxylic acid or an ester-forming derivative thereof as main structural units. A method for producing a highly moisture-permeable polyester film, which is a polymer or a mixture with another polymer containing the polymer.   The olefin resin according to claim 6 is (A) a polymer having at least one or more kinds of α-olefin having 2 to 6 carbon atoms as a main structural unit, and (B) at least one or more kinds of carbon atoms having 2 to 6 carbon atoms. A method for producing a highly moisture-permeable polyester film, comprising a copolymer mainly comprising an α-olefin and an ethylene bond-forming α, β-unsaturated carboxylic acid or an ester-forming derivative thereof.