JP2005154636A - Moisture-proofing polyester sheet and vessel for ptp packaging container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moisture-proofing polyester sheet having excellent moldability and steam barrier properties, and suitable for packaging a foodstuff and a medicine; and to provide a vessel for PTP (press-through package) packaging container. <P>SOLUTION: The moisture-proofing polyester film comprises in forming 5-20 μm thickness coating layer composed of a halogen-free water-repellent resin such as a styrene-butadiene resin onto either face of a non-oriented amorphous substrate sheet composed mainly of a polyester. The PTP packaging container obtained by molding the same, is also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a moisture-proof polyester sheet and a PTP packaging sheet. More specifically, the present invention relates to a moisture-proof polyester sheet and a PTP packaging container suitable for packaging materials and industrial materials, which have excellent molding processability and excellent water vapor barrier properties.

  Polyester sheets, especially non-oriented amorphous sheets of polyethylene terephthalate (hereinafter also referred to as PET), are excellent in moldability, mechanical strength, and transparency, and are widely used as industrial and food packaging sheets. Yes. However, when used as a food packaging sheet, the polyester sheet alone lacks a barrier property, so-called gas barrier property such as oxygen and water vapor, which is one of the extremely important performances for food packaging materials.

  Therefore, for applications requiring water vapor barrier properties, sheets of olefin resins such as polypropylene, polyvinyl chloride, and the like have been used instead of polyester resin materials. However, in the case of an olefin-based resin, there are problems in processability difficulty and transparency. In the case of a polyvinyl chloride resin, the moldability is good and the mechanical properties are not particularly problematic, but there are environmental problems such as generation of dioxins during combustion.

Recently, a polyester resin that is well balanced in terms of environmental problems and mechanical properties has attracted attention, and the amount of polyester sheet used has increased.
In order to improve the gas barrier property, vapor deposition of a metal or a metal oxide or lamination of a gas barrier organic substance is performed. In the case of vapor deposition of metals and metal oxides, there is a disadvantage that they are not durable against a process in which deformation or stress occurs during the molding process, and it is economically expensive. As for the method of applying and laminating polyvinylidene chloride as an organic resin having a gas barrier property, an alternative is demanded from the viewpoint of environmental load as in the case of polyvinyl chloride. Moreover, although the method of laminating | stacking a metaxylylene group containing polyamide on a polyester sheet is disclosed, water vapor | steam barrier property is inadequate. (See JP-A-8-300586) Although a method using polyethylene naphthalate or polyethylene isophthalate instead of PET is also disclosed, it has a drawback that the molded product is brittle. (See JP-A-8-300586 and JP-A-61-43561)
JP-A-8-300586 Japanese Patent Laid-Open No. 10-250015 Japanese Patent Laid-Open No. 61-43561

  The present invention solves the above problems, and provides a moisture-proof polyester sheet suitable as a packaging material having excellent molding processability and excellent water vapor barrier properties, and a PTP packaging container obtained therefrom. is there.

  The moisture-proof polyester sheet according to the present invention is characterized in that a coating layer having a thickness of 5 to 20 μm made of a water-repellent resin containing no halogen is formed on at least one surface of a non-oriented base sheet mainly made of polyester. It is. A preferred embodiment is a moisture-proof polyester sheet in which the polyester is a polyester comprising an aromatic dicarboxylic acid component and a glycol component, particularly a polyester having ethylene terephthalate as a main repeating unit. Moreover, this invention is a container for PTP packaging obtained by shape | molding the said moisture-proof polyester sheet.

In the moisture-proof polyester sheet of the present invention, a moisture-proof layer made of a water-repellent resin is formed on at least one side of a substrate sheet made of polyester. The moisture-proof layer made of the water-repellent resin has excellent adhesion to the substrate sheet, and has a stretchability that can sufficiently withstand a molding process such as vacuum molding, and the moisture-proof layer is peeled off from the substrate sheet. Or, since the moisture-proof layer is prevented from cracking, excellent gas barrier properties can be exhibited. In this case, the moisture-proof layer is made of a water-repellent resin, thereby inhibiting the adsorption of water vapor and reducing the water vapor permeability of the polyester sheet on which the moisture-proof layer is formed.
That is, the moisture-proof polyester sheet of the present invention having such a moisture-proof layer has the characteristics of being excellent in molding processability and excellent in water vapor barrier properties after molding. Therefore, it is a polyester sheet suitable for packaging applications requiring water vapor barrier properties.

The present invention is described in detail below.
The polyester used as the base sheet of the present invention is preferably a polyester mainly obtained from an aromatic dicarboxylic acid component and a glycol component, and more preferably, the aromatic dicarboxylic acid component unit is 85 mol% or more of the acid component. Particularly preferred are polyesters in which the aromatic dicarboxylic acid unit contains 95 mol% or more of the acidic component.

  Examples of the aromatic dicarboxylic acid component constituting the polyester according to the present invention include terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenol-4, 4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid and other aromatic dicarboxylic acids, and The functional derivative is mentioned.

  Examples of the glycol component constituting the polyester according to the present invention include alicyclic glycols such as ethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, and cyclohexanedimethanol.

  Examples of the acid component used by copolymerization in the polyester include aromatic dicarboxylic acids such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, diphenyl-4,4′-dicarboxylic acid, and diphenoxyethanedicarboxylic acid. Acids, oxyacids such as p-oxybenzoic acid and oxycaproic acid and their functional derivatives, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, glutaric acid and dimer acid and their functional derivatives, hexahydroterephthalate Examples thereof include alicyclic dicarboxylic acids such as acids, hexahydroisophthalic acid and cyclohexanedicarboxylic acid, and functional derivatives thereof.

  Examples of the glycol component used by copolymerization in the polyester include aliphatic glycols such as ethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, diethylene glycol, and neopentyl glycol, and alkylene oxide adducts of bisphenol A. Aromatic glycol, polyethylene glycol, polyalkylene glycol such as polybutylene glycol, and the like.

  Furthermore, monofunctional compounds such as benzoic acid and naphthoic acid may be copolymerized, and polyfunctional compounds such as trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, glycerin, pentaerythritol, and trimethylolpropane. Etc. may be copolymerized.

  The most preferred example of the polyester according to the present invention is a linear polyester in which the main repeating unit is composed of ethylene terephthalate, more preferably a linear polyester containing 85 mol% or more of ethylene terephthalate units, particularly preferably ethylene terephthalate. A linear polyester containing 95 mol% or more of units is preferable because of its excellent transparency and mechanical strength.

  Another preferred example of the polyester according to the present invention is a linear polyester in which the main repeating unit is composed of ethylene-2,6-naphthalate, and more preferably 85 mol% of ethylene-2,6-naphthalate units. Of these, linear polyesters containing 95 mol% or more of ethylene-2,6-naphthalate units are particularly preferred because they are excellent in transparency, mechanical strength, heat resistance, and the like.

Other preferable examples of the polyester according to the present invention include a linear polyester containing 85 mol% or more of propylene terephthalate units, a linear polyester containing 85 mol% or more of 1,4-cyclohexanedimethylene terephthalate units, or a butylene terephthalate unit. Is a linear polyester containing 85 mol% or more.
The above polyesters can be used in a mixture of at least one of them within a range that does not impair the intended characteristics of the present invention.

  Said polyester can be manufactured by a conventionally well-known manufacturing method. That is, in the case of PET, terephthalic acid, ethylene glycol and, if necessary, other copolymerization components are directly reacted to distill off water and esterify, and then a compound of Ge, Sb, Ti, or aluminum as a polycondensation catalyst And at least one compound and stabilizer as phosphoric acid compound, phosphorous acid compound, phosphonic acid compound, phosphinic acid compound, phosphinic oxide compound, phosphonous acid compound, phosphinic acid compound, phosphine A direct esterification method in which polycondensation is performed under reduced pressure using at least one of the compounds, or as a transesterification catalyst, at least of compounds such as magnesium compounds, calcium compounds, cobalt compounds, manganese compounds, and zinc compounds Using one compound, dimethyl terephthalate and ethylene Produced by a transesterification method in which glycol and other copolymerization components are reacted to distill off methyl alcohol and transesterify, followed by polycondensation under reduced pressure using the above polycondensation catalyst or stabilizer. .

  If necessary, solid state polymerization can be performed to increase the intrinsic viscosity. In order to promote crystallization before solid-phase polymerization, the melt polycondensed polyester may be subjected to heat crystallization after moisture absorption, or water vapor may be directly sprayed onto the polyester chip for heat crystallization.

  The melt polycondensation reaction may be performed in a batch reactor or may be performed in a continuous reactor. In any of these methods, the melt polycondensation reaction may be performed in one stage or may be performed in multiple stages. The solid phase polymerization reaction can be carried out by a batch type apparatus or a continuous type apparatus, similarly to the melt polycondensation reaction. Melt polycondensation and solid phase polymerization may be carried out continuously or separately.

  The intrinsic viscosity of the polyester used in the present invention is 0.63 to 2.00 dl / g, preferably 0.65 to 1.50 dl / g, more preferably 0.70 to 1.00 dl / g. When the intrinsic viscosity is less than 0.63 dl / g, it is very difficult to maintain the intrinsic viscosity of the moisture-proof polyester sheet base sheet at 0.60 dl / g, and the tensile impact of the base sheet obtained as described below The strength characteristics are extremely lowered, which causes a problem. Further, to obtain a polyester exceeding 2.00 dl / g is only by a solid phase polymerization reaction for a long time, which leads to an increase in cost and causes a problem in economy.

  The polyester base sheet according to the present invention is preferably a mixture of at least one polyester selected from the above polyesters and an amorphous polyester. By making such a mixture, the adhesion between the polyester base sheet and the moisture-proof layer, or the adhesion between the undercoat layer is improved, and peeling and the like are less likely to occur. Can be suppressed.

The amorphous polyester is preferably a polyester in which an aromatic dicarboxylic acid unit contains 85 mol% or more of the acid component, and particularly preferably a linear polyester in which the aromatic dicarboxylic acid unit contains 95 mol% or more of the acid component.
As the dicarboxylic acid component and the glycol component used in the amorphous polyester resin, those described above are similarly used. As the aromatic dicarboxylic acid, terephthalic acid and naphthalenedicarboxylic acid are preferable.
As the glycol, those in which an aliphatic or alicyclic glycol having 2 to 10 carbon atoms is copolymerized are preferable, and further, diethylene glycol, neopentyl glycol, cyclohexanedimethanol with respect to 50 to 95 mol% of ethylene glycol. It is preferable that at least one of the above is copolymerized in an amount of 5 to 50 mol%. Among these, a combination of ethylene glycol and neopentyl glycol, ethylene glycol and cyclohexanedimethanol is preferable.
The amorphous polyester resin according to the present invention includes a dicarboxylic acid other than terephthalic acid and naphthalenedicarboxylic acid, and a polyhydric alcohol component other than ethylene glycol, diethylene glycol, neopentyl glycol, and cyclohexanedimethanol. It may be polymerized.

The addition amount of the amorphous polyester needs to be in a range that does not impair the characteristics of the moisture-proof polyester sheet aimed at by the present invention.
The intrinsic viscosity of the amorphous polyester is preferably 0.4 dl / g or more, more preferably 0.5 dl / g or more, 2.0 dl / g or less, and further 1.5 dl / g or less. preferable.

  The content of the cyclic oligomer in the polyester base sheet according to the present invention is preferably 0.70% by mass or less. When the content of the cyclic oligomer in the polyester base sheet exceeds 0.70% by mass, the adhesion between the polyester base sheet and a moisture-proof coating layer described later deteriorates, so that moisture resistance is prevented during molding. The layers can come off and cause problems. This is because the cyclic oligomer precipitates on the surface of the polyester base sheet due to the action of the solvent in the coating solution or heat at the time of drying when applying the moisture-proof layer, etc. The cyclic oligomer contained in the polyester base sheet is transferred to the coating liquid, which causes clogging of the gravure roll, resulting in coating unevenness and incomplete coating of the moisture-proof layer. Become. In addition, due to these causes, pinholes are generated in the moisture-proof layer and the moisture-proof layer is not sufficiently uniform, and cracks are generated in the moisture-proof layer after molding.

  In order to maintain the content of the cyclic oligomer of the polyester base sheet according to the present invention at 0.70% by mass or less, it is preferable to obtain a base sheet using at least about 0.68% by mass or less of polyester. . In addition, as a method for reducing the polyester cyclic oligomer to 0.68% by mass or less, the above-described solid-phase polymerization method, heat treatment method and the like can be employed. In addition, since oligomers increase during the production of the polyester base sheet, it is preferable not to raise the extrusion temperature and the like higher than necessary during the production of the sheet, and it is necessary to pay attention to shortening the melting time. . The amount of oligomer in the polyester base sheet is 0.05% by mass or more from the viewpoint of realistic production.

  Here, the polyester generally contains cyclic oligomers having various degrees of polymerization. The cyclic oligomer referred to in the present invention means a cyclic oligomer having the highest content among the cyclic oligomers contained in the polyester. For example, in the case of polyester having ethylene terephthalate as the main repeating unit, it is a cyclic trimer.

  Furthermore, the content of diethylene glycol units (abbreviated as DEG) in the polyester according to the present invention is preferably in the range of 1.0 to 5.0 mol%. If the DEG content is less than 1.0 mol%, the adhesion between the resulting polyester base sheet and the moisture-proof coating layer to be described later becomes weak, and the moisture-proof layer peels off during PTP molding, which is a problem. There is. Moreover, in terms of polyester production, it is necessary to produce under conditions with very poor productivity, which is not realistic. Further, when the DEG content exceeds 5.0 mol%, crazing due to a solvent is likely to occur on the surface of the polyester base sheet when the moisture-proof layer is applied, and the moisture-proof layer is likely to crack during stretching. is there. For this reason, the tensile impact strength characteristics of the moisture-proof polyester sheet may be deteriorated, and cracks may occur during PTP molding, which may be a problem.

  Further, a thermoplastic polyester elastomer such as a polyester / polyether elastomer or a polyester / polyester elastomer can be further added to the polyester base sheet according to the present invention as long as the target properties of the present invention are not impaired.

  In addition, the polyester composition constituting the polyester base sheet according to the present invention is a known ultraviolet absorber, antioxidant, oxygen absorber, oxygen scavenger, lubricant added from the outside, and internal precipitation during the reaction. Various additives such as a lubricant, a release agent, a nucleating agent, a stabilizer, an antistatic agent, and a pigment can be appropriately added within a range that does not impair the intended characteristics of the present invention.

The method for producing the polyester base sheet according to the present invention is not particularly limited, but the polyester composition is melted and extruded from a die by a T-die extrusion method using a single-screw extruder or a twin-screw extruder, and then on a cooling drum. To obtain a non-oriented amorphous polyester sheet having a predetermined width and thickness. The polyester base sheet according to the present invention is preferably non-orientated in terms of formability, but it is uniaxial or biaxial as long as it is up to 1.5 times within a range where formability and transparency are not a problem. It may be stretched and oriented. The degree of crystallization of the polyester base sheet according to the present invention may be crystallized as long as moldability and transparency are not problematic. In order to suppress crystallization, it is preferable to increase the cooling rate of the molten resin when cast on a cooling drum. Therefore, when a touch roll or a multistage cooling roll is used, a polyester base sheet having excellent moldability and transparency can be obtained.
Further, the polyester base sheet according to the present invention may be a single-layer sheet made of the polyester composition or a multilayer sheet in which two or more kinds of polyesters are laminated.

The thickness of the polyester base sheet of the present invention varies depending on the purpose of use, but is in the range of 0.05 to 1.5 mm. For example, when used for PTP packaging, 0.1 to 0.4 mm is preferable.
The tensile impact strength of the polyester base sheet according to the present invention is 20 kj / m ² or more, preferably 30 kj / m ² or more, more preferably 35 kj / m ² or more, and most preferably 40 kj / m ² or more. desirable. When the tensile impact strength of the polyester base sheet is less than 20 kj / m ^{2, the} impact resistance after applying the moisture-proof layer is lowered, and cracking may occur during PTP molding.

Due to the influence of the coating solution at the time of applying the moisture-proof layer, the surface of the polyester base sheet may crack, and the impact resistance may be lowered. In anticipation of this decrease, it is preferable to ensure high impact resistance as a polyester base sheet. The intrinsic viscosity of the polyester base sheet according to the present invention is preferably 0.60 dl / g or more, more preferably 0.65 dl / g or more, further preferably 0.70 dl / g or more, and most preferably 0.75 dl / g. g or more. When the intrinsic viscosity of the obtained polyester base sheet is less than 0.60 dl / g, the tensile impact strength may not reach ²⁰ kj / m ² .
Examples of a method for setting the tensile impact strength of the polyester base sheet to 20 kj / m ² include a method for setting the intrinsic viscosity of the polyester base sheet to 0.60 dl / g or more, a method for blending amorphous polyester, and the like. Use as appropriate. When a multilayer base sheet is used, it is desirable that the polyester of any constituent layer has an intrinsic viscosity of 0.60 dl / g or more.

The moisture-proof layer in the present invention requires that the constituent resin has water repellency. Examples of the resin having water repellency include hydrocarbon resins and silicon resins.
Examples of the hydrocarbon resin include polyolefins, long chain alkyl group-containing resins, rubbers, rubber components, and the like.
As the silicone resin, a polydimethylsiloxane containing a silanol group at the terminal which is a condensation type is used as a base polymer, polymethylhydrogensiloxane is blended as a cross-linking agent, and condensation is performed by heating in the presence of an organotin catalyst. Addition-type polydimethylsiloxane containing vinyl group as a base polymer, blending polymethylhydrogensiloxane as a cross-linking agent, reacting and curing in the presence of platinum catalyst, or using photocationic curing mechanism UV curable type.

As a measure of water repellency, the surface energy calculated from the contact angle of water or the contact angle of water and methylene iodide (method described in J. Appl. Polym. Sci., 1969, Vol. 13, p. 1741) is used. Can be used.
As the moisture-proof layer comprising the water-repellent resin of the present invention, a layer having a contact angle of water of preferably 70 degrees or more, more preferably 80 degrees or more, and most preferably 90 degrees or more is used. It is valid. The upper limit of the contact angle of water is not particularly limited, but is generally 120 degrees or less. With respect to the surface free energy of the moisture-proof layer, preferably 50 dynes / cm or less, more preferably 45 dynes / cm or less, and most preferably 40 dynes / cm or less, good moisture resistance can be exhibited. In addition, when the hydrogen bond component of the surface free energy of the moisture-proof layer is 9 dynes / cm or less, good moisture-proof properties are exhibited.

  As a method for laminating the moisture-proof layer made of the water-repellent resin in the present invention, a coating (coating) method is applied because of its simplicity and ease of adjustment of practical characteristics. As the resin in this case, an organic solvent-soluble resin, or a water-soluble resin or a water-dispersible resin can be used. Examples of the organic solvent-soluble resin include silicon-based resins. Examples of the water-soluble resin and water-dispersible resin include rubber latex and polyolefin emulsion. Of these, SBR latex is preferred as the rubber latex from the viewpoint of the adhesion of the polyester to the substrate sheet and the water repellency.

  In the present invention, the moisture-proof layer made of the water-repellent resin has a thickness of 5 to 20 μm after coating and drying. If it is thinner than 5 μm, the moisture-proof property is lowered, and if it is thicker than 20 μm, brushing or blocking occurs when the laminated sheet is rolled up, and the moisture-proof layer shows through, the moisture-proof layer breaks when the sheet is unwound, and the sheet is cut. The harmful effects of

  In addition to the main components described above, one or more additives may be appropriately mixed with the coating solution as long as the formability, blocking property, and moisture resistance of the moisture-proof sheet are not affected. There are no particular restrictions on the additive used, for example, various commonly used leveling agents, dyes, pigments, pigment dispersants, ultraviolet absorbers, antioxidants, viscosity modifiers, light stabilizers, metal inertness Agent, peroxide decomposing agent, filler, reinforcing agent, plasticizer, lubricant, anticorrosive agent, anticasting agent, emulsifier, mold bleaching agent, fluorescent whitening agent, organic flameproofing agent, inorganic flameproofing agent, Examples thereof include an anti-drip agent, a melt flow modifier, and an antistatic agent.

  As a method of applying a water repellent resin coating solution to a polyester base sheet, a conventionally known dipping method, spray method, gravure coating method, reverse roll coating method, direct roll coating method, curtain flow coating method, air knife coating method, A squeeze coating method, a kiss coating method, a blade coating method, a comma coating method, or the like may be used. In order to obtain good moisture resistance and a uniform coating layer thickness, it is desirable to use a gravure coating method. After coating, the coating solution can be dried at 40 to 100 ° C. to obtain a coating layer of the water repellent resin.

  The moisture-proof polyester sheet of the present invention is subjected to surface activation treatment such as corona treatment on its surface, and various performances are added by printing, various functional coatings, laminating, and the utility value is further improved. It is also possible.

  The moisture-proof polyester sheet of the present invention is subjected to drawing, bending, twisting, and the like by methods such as vacuum forming, pressure forming, and plug assist forming, but is not limited thereto. Since the moisture-proof polyester sheet of the present invention has moldability and moisture-proof property, it is particularly useful as a PTP packaging container for foods, chemicals and metal parts. In addition, PTP packaging (Press Through Package) is one of packaging forms such as tablets and capsules, and is a packaging form in which medicine can be taken out by pushing with a finger. It has features such as sealability, transparency, take-out property, releasability, portability, etc. in a single tablet unit, and it is widely used as a packaging form for pharmaceuticals and foods. A sheet is thermoformed according to the shape of various tablets or the like to be packaged, the pocket is filled with the package, and sealed with aluminum foil or the like.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The main characteristic value measuring methods in this specification will be described below.
(1) Intrinsic viscosity of polyester (IV)
It calculated | required from the solution viscosity in 30 degreeC in the 1, 1, 2, 21 tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent.

(2) Thickness of base material sheet and moisture-proof coating layer The thickness of the base material sheet before providing the coating layer of the water-repellent resin was measured using a micrometer (Finereuf Co., Ltd., Millitron 1245D). The thickness of the coating layer is determined by removing the coating layer by rubbing the coating layer surface of the sheet after coating and drying with gauze containing ethyl alcohol, and measuring the thickness of the sheet before and after removing the coating layer with a micrometer The thickness of the coating layer was calculated from the difference measured using Millitron 1245D).

(3) Water contact angle of water-repellent resin Ion exchange on the coating layer surface of the coated and dried sheet using a contact angle meter CA-X type manufactured by Kyowa Interface Science Co., Ltd. at 25 ° C. and 60 RH% atmosphere. About 0.05 ml of water was dropped, and the contact angle after 30 seconds was measured.

(4) Haze value Two non-oriented amorphous polyester sheets coated with the produced moisture barrier layer were cut into 8 cm × 10 cm strips, and a haze meter (TC Density Co., Ltd., TC-H3DP) Measure each 8 points twice. The average value of the total 16 measured values was defined as the haze value (%).
(5) Measurement of water vapor barrier property A measuring instrument (MOCON, USA) manufactured by MOCON (MOCON, USA) was used for the non-oriented amorphous polyester sheet coated with the moisture-proof layer and laminated at 40 ° C. and 100% RH. PARMATRAN-W).

(6) Evaluation of set-off property A water-repellent resin coating solution was applied to the base sheet, then dried, and then continuously wound into a roll on a 6-inch paper tube. The wound roll was allowed to stand in a room at 25 ° C. for 3 days, and then the sheet was unwound, and the surface of the sheet was visually observed and evaluated as x for those with set-off and O for those without set-up.

(7) Molding evaluation The produced moisture-proof layer was coated and laminated on a non-oriented amorphous polyester sheet at 90 ° C. at 90 ° C. with a biaxial stretching device (manufactured by Toyo Seiki Co., Ltd.) 200 ×. Simultaneously biaxially stretched at a ratio of 200% to obtain a stretched sample that assumes deformation in thermoforming. The visually uniform stretch is ○, the non-uniform stretch is x, and the haze after stretch deformation Value and water vapor barrier properties were evaluated.

(7) PTP molding processability The non-oriented amorphous polyester sheet coated with the produced moisture barrier layer is slit, wound into a roll, set in a vacuum molding machine and molded at a molding temperature of 100 ° C. ( No. 3 capsules) were molded and the water vapor barrier property after the molding process was evaluated.

(Example 1)
PET with an intrinsic viscosity of 0.75 dl / g is pre-crystallized, then vacuum dried at 130 ° C. for 10 hours, melt-extruded at 280 ° C. using an extruder having a T die, and rapidly cooled and solidified on a drum having a surface temperature of 40 ° C. Thus, a non-oriented and amorphous polyester sheet having a thickness of 200 μm was obtained. On one side of the obtained sheet, a styrene-butadiene resin latex (Pateracol (R) 527, manufactured by Dainippon Ink & Chemicals, Inc., solid content 46% by mass) is dried by a gravure roll coating method so that the thickness becomes 10 μm. Then, it was led to a drying furnace and dried at 70 ° C. for 3 minutes to obtain a laminated polyester sheet on which a moisture-proof layer having a thickness of 210 μm was formed. Table 1 shows the results of measuring the transparency and water vapor barrier properties of the polyester sheet on which the moisture barrier layer was formed.

(Examples 2 and 3, Comparative Examples 1 to 4)
A non-oriented amorphous material in which a moisture-proof layer is applied and laminated in the same procedure as in Example 1, except that the coating liquid and coating layer thickness of the water repellent resin, and the type of base sheet are changed as shown in Table 1. A polyester sheet was obtained. Table 1 shows the results of measuring the transparency and water vapor barrier properties of the polyester sheet on which the moisture barrier layer was formed. In Comparative Example 2, polypropylene (PP: melting point 160 ° C., melt flow rate 2.5 g / 10 min, manufactured by Sumitomo Chemical Co., Ltd.) was used as a raw material for the base sheet.

Example 4
100 parts by mass of PET having an intrinsic viscosity of 1.02 dl / g, terephthalic acid having an intrinsic viscosity of 0.73 dl / g, ethylene glycol (abbreviated as EG) and neopentyl glycol (abbreviated as NPG) obtained by solid phase polymerization ) 5 parts by weight of a copolyester (EG / NPG copolymerization ratio = 7/3, intrinsic viscosity 0.73 dl / g) is extruded at 280 ° C. using an extruder having a T die, and a surface temperature of 40 A non-oriented amorphous polyester sheet having a thickness of 200 μm was obtained by rapid solidification on a drum at 0 ° C. On one side of the obtained sheet, a styrene-butadiene resin latex (Pateracol (R) 527, manufactured by Dainippon Ink & Chemicals, Inc., solid content 46% by mass) is dried by a gravure roll coating method so that the thickness becomes 10 μm. And then led to a drying oven and dried at 70 ° C. for 3 minutes to obtain a polyester sheet having a thickness of 210 μm. The laminated polyester sheet on which the moisture-proof layer was formed had a haze value of 1.3% and a water vapor barrier property of 3 g / m ² / day. The workability of the drawing process was good, the haze value after drawing deformation was 1.2%, and the water vapor barrier property was 5 g / m ² / day.

＊１：ＳＢＲラテックス（大日本インキ化学工業（株）製、パテラコール（Ｒ）５２７）
＊２：ポリオレフィンエマルジョン（東邦化学工業（株）製、ハイテック（Ｒ）３１２１）
＊３：シリコーン樹脂（ＧＥ東芝シリコーン（株）製、ＵＭ−１１０）

* 1: SBR latex (manufactured by Dainippon Ink and Chemicals, Pateracol (R) 527)
* 2: Polyolefin emulsion (manufactured by Toho Chemical Co., Ltd., Hitech (R) 3121)
* 3: Silicone resin (GE Toshiba Silicone Co., Ltd., UM-110)

(Example 5)
The polyester sheet on which the moisture-proof layer obtained in Example 1 was formed was slit to produce a roll-shaped sheet, and a PTP container (No. 3 capsule) was molded at a molding temperature of 100 ° C. with a vacuum molding machine. Molding can be performed without any problem, transparency is good, and there is no blocking or width shrinkage of the heating part before vacuum molding. The thickness of the processed part of the molded product was 56 μm on the side and 135 μm on the top. The moisture permeability of No. 3 capsule size 10 pocket 1 sheet was 13.2 mg / 1 sheet / day.

  As in Examples 1 to 5, the polyester sheet on which the moisture-proof layer of the present invention was formed had higher water vapor barrier properties than the polyester sheet without the moisture-proof layer of Comparative Example 1, and polyester compared to the polypropylene sheet of Comparative Example 2 It retains the excellent thermoformability and transparency that are the features of the sheet. Further, in Comparative Examples 3 and 4, since the thickness of the moisture-proof layer is outside the range of the present invention, there is a problem that the water vapor barrier property is insufficient or the moisture-proof layer is reversed.

  ADVANTAGE OF THE INVENTION According to this invention, the moisture-proof polyester sheet which can maintain high water vapor | steam barrier property after a shaping | molding process can be provided. The moisture-proof polyester sheet of the present invention is useful for foods such as PTP packaging, pharmaceutical packaging sheets, and general industrial sheets such as electrical and electronic parts, building materials, photoengraving, adhesive tapes, and mold release. .

Claims (4)

  A moisture-proof polyester sheet, characterized in that a coating layer having a thickness of 5 to 20 μm made of a water-repellent resin not containing halogen is formed on at least one surface of a non-oriented base sheet mainly made of polyester.   The moisture-proof polyester sheet according to claim 1, wherein the polyester is a polyester mainly composed of an aromatic dicarboxylic acid component and a glycol component.   The moisture-proof polyester sheet according to claim 1, wherein the polyester is a polyester having ethylene terephthalate as a main repeating unit.   A container for PTP packaging, which is obtained by molding the moisture-proof polyester sheet according to claim 1.