JP2007046023A - Unoriented polybutylene terephthalate resin film and laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an unoriented polybutylene terephthalate resin film having excellent slip properties without the loss of transparency. <P>SOLUTION: The unoriented polybutylene terphthalate resin film is obtained by making into a film a resin composition containing (a) 95-99.9 wt.% of a polyester resin composed mainly of a butylene terephthalate unit, (b) 0.05-2.5 wt.% of a mold release agent compatible with the polyester resin (a), and (c) 0.05-2.5 wt.% of an antiblocking agent having an average particle size of 1-15 μm. The unoriented laminated film is obtained by laminating such polybutylene terephthalate resin film layer (A) as an outermost layer with a heat sealable resin layer (C) or successively with a gas barrier resin layer (B) and the heat sealable resin layer (C). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an unstretched polybutylene terephthalate resin film. The present invention also relates to a laminated film obtained by further laminating a heat-sealable resin layer or a gas barrier resin layer and a heat-sealable resin layer on the layer made of such a film. Thus, the film according to the present invention is excellent in transparency and slipperiness and is useful as a packaging material for foods and the like.

  Polybutylene terephthalate resin (hereinafter sometimes abbreviated as “PBT”) can be processed, mechanical properties, heat resistance, chemical resistance, and fragrance even without being biaxially stretched like polyethylene terephthalate. Therefore, it is widely used in various applications as a single layer or as a laminated film with other resin layers. For example, an unstretched laminated film obtained by laminating a gas barrier resin layer and a heat sealable resin layer on a PBT film is known as a food packaging material.

  However, since the unstretched PBT film itself has a large coefficient of friction and is inferior in slipperiness, when it is turned into a film and rolled up, it is easy to cause problems such as wrinkles and ears up. Was significantly reduced. Also, when processed into a food packaging bag or the like, excellent anti-blocking properties during lamination storage are required.

As means for solving these problems and satisfying the required physical properties, Patent Document 1 arranges a polyester resin layer containing an antiblocking agent composed of organic fine particles in the outermost layer, and provides slipperiness due to unevenness on the outermost film surface. We have proposed a food packaging bag consisting of improved product Sofu Irumu.

However, in the method of improving the slipperiness with the fine particle antiblocking agent, it is necessary to add a large amount of fine particles in order to obtain a sufficient slipperiness, so that the film haze increases remarkably or the film becomes cloudy and the transparency is lost. There was a case.
Japanese Patent Laid-Open No. 11-77937

  This invention is made | formed in view of this situation, Comprising: It aims at providing the unstretched polybutylene terephthalate resin film which has the outstanding slipperiness, without losing transparency.

  The present inventor has intensively studied to achieve the above object, and by forming a film in which a specific release agent is blended with a fine particle antiblocking agent in PBT, the present inventors have not yet achieved excellent transparency and a low friction coefficient. The present invention has been achieved by successfully obtaining a stretched film. That is, the gist of the present invention is as follows: (a) 95 to 99.9% by weight of a polyester resin having a butylene terephthalate unit as a main component, and (b) a mold release agent having a compatibility with the polyester resin (a) 0.05 to 2 Unstretched polybutylene terephthalate resin film formed by forming a resin composition containing 5% by weight and (c) 0.05 to 2.5% by weight of an antiblocking agent having an average particle diameter of 1 to 15 μm, and such The layer (A) made of polybutylene terephthalate resin film is the outermost layer, and the heat-sealable resin layer (C) is further laminated, or the gas barrier resin layer (B) and the heat-sealable resin layer (C) are sequentially laminated. It exists in the unstretched laminated film formed.

  According to the present invention, it is possible to obtain an unstretched PBT film having excellent transparency with an L value of less than 15 as measured by color tone and excellent slipperiness with a dynamic friction coefficient of less than 0.40. It is possible to prevent the occurrence of wrinkles, ear-earing and the like when rolled up. In addition, the unstretched PBT film of the present invention is a single layer or a laminated film in which a gas barrier resin layer or a heat resin layer is further laminated, and has excellent slipperiness without losing transparency. It is used in a wide range of applications as a decorative other film.

Hereinafter, the present invention will be described in detail.
The PBT layer (hereinafter referred to as PBT film) of the unstretched PBT film or laminated film of the present invention has (a) a polyester resin mainly composed of a butylene terephthalate unit, and (b) a compatibility with the polyester resin (a). And (c) an antiblocking agent having an average particle diameter of 1 to 15 μm.

(A) Polyester resin based on a butylene terephthalate unit The polyester resin (a) used in the present invention is usually 1,4-butanediol or a polyhydric alcohol component based on this and terephthalic acid or It is obtained by a polycondensation reaction with an ester-forming derivative such as methyl ester (hereinafter collectively referred to as “terephthalic acid etc.”) or a polyvalent carboxylic acid component containing terephthalic acid as a main component.

  Examples of polyvalent carboxylic acid components other than terephthalic acid include aromatic polyvalent carboxylic acids such as 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, isophthalic acid, phthalic acid, trimesic acid, and trimellitic acid. Acid; aliphatic dicarboxylic acid such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid; alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid; And ester-forming derivatives such as methyl carboxylic acid methyl esters. One or more of these various polyvalent carboxylic acid components are used as a polycondensation component together with terephthalic acid as a main component.

  Examples of polyhydric alcohol components other than 1,4-butanediol include aliphatic polyhydrides such as ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, pentanediol, hexanediol, glycerin, trimethylolpropane, and pentaerythritol. Monohydric alcohols; alicyclic polyhydric alcohols such as 1,4-cyclohexanedimethanol; aromatic polyhydric alcohols such as bisphenol A and bisphenol Z; polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene oxide glycol, etc. Examples include polyalkylene glycol. One or more of these various polyhydric alcohol components are used as a polycondensation component together with 1,4-butanediol as a main component.

  In the present invention, the main component is a butylene terephthalate unit. Among polyvalent carboxylic acid components used as a polycondensation component, terephthalic acid or an ester-forming derivative thereof is 50 mol% or more, preferably 60 mol% or more. More preferably, it is 70 mol% or more, and among the polyhydric alcohol components used as the polycondensation component, 1,4-butanediol is 50 mol% or more, preferably 60 mol% or more, more preferably It means 70 mol% or more.

  The production method of the polyester resin (a) used in the present invention is not particularly limited, and a polyvalent carboxylic acid mainly composed of terephthalic acid and a polyhydric alcohol mainly composed of 1,4-butanediol; Either a method of directly polycondensation of a polyvalent carboxylic acid ester or a method of transesterification polycondensation of a polyvalent carboxylic acid ester and a polyhydric alcohol may be used. Also, the polymerization format is not particularly limited, and any known format such as a melt polymerization format or a combination of melt polymerization and solid phase polymerization can be adopted. In the polycondensation reaction, a titanium compound, a magnesium compound, a calcium compound, and other catalysts and cocatalysts are used as necessary. Depending on the amount of the metal derived from these catalysts in the polyester resin (a), it may be produced. For example, when a titanium compound is used as a catalyst, the amount of titanium atoms in the polyester resin (a) should be 120 ppm by weight or less because the film may cause generation of foreign matters or deterioration of color tone. Is preferred.

  The polyester resin (a) used in the present invention preferably has an intrinsic viscosity of 0.7 dl / g or more and 2 dl / g or less. The intrinsic viscosity is more preferably 0.8 dl / g or more, further preferably 1 dl / g or more, preferably 1.8 dl / g or less, more preferably 1.6 dl / g or less. If the intrinsic viscosity is too low, the mechanical strength of the molded product may be insufficient. On the other hand, if it is too high, the melt viscosity of the resin composition of the present invention will be high, the extruder screw load will be high, and the extrusion amount will be high. descend. In the present invention, the intrinsic viscosity of the polyester resin (a) is a value determined from the solution viscosity measured at 30 ° C. in a phenol / 1,1,2,2-tetrachloroethane (weight ratio 1/1) solvent. is there.

The polyester resin (a) used in the present invention may be a mixture of a plurality of types having different constituent components, intrinsic viscosities, terminal carboxyl group concentrations, melting points and the like as long as these conditions are satisfied.
The usage-amount of a polyester resin (a) is the quantity used as 95-99.9 weight% of the resin composition which comprises the unstretched PBT film of this invention.

(B) Release agent having compatibility with polyester resin (a) The release agent (b) used in the present invention has good compatibility with the polyester resin (a). If the compatibility with PBT is poor, the film formed may become cloudy and the transparency may be impaired. Also, the casting roll stains during film formation, especially cooling water in the water-cooled inflation method. There is a risk of causing contamination.

  In general, the term "release agent" is a term that refers to a substance used to prevent the sticking of a mold to a molded product and facilitate the mold release operation in a molding method that uses a mold during molding such as injection molding. Examples thereof include hydrocarbon-based waxes such as paraffin wax and polyethylene wax, and wax-based release agents such as those partially modified.

  The paraffin wax is a petroleum wax mainly composed of n-paraffin, and among them, those having a melt viscosity of 0.1 poise or less at a temperature of 100 ° C. and a melting point of 50 to 70 ° C. are preferable. Polyethylene wax refers to a low molecular weight polyethylene having a waxy appearance and having a molecular weight intermediate between paraffin and molding polyethylene. Specific examples include low molecular weight polyethylene, low molecular weight polyethylene copolymers, or modified polyethylene wax of a type in which polar groups are introduced by oxidizing or acid-modifying them. The number average molecular weight is about 500 to 15000, but considering the compatibility with the polyester resin (a), a molecular weight of 2000 or less is preferable.

  Preferred release agents (b) having an important role in the modification of PBT in the present invention include higher fatty acids, higher fatty acid metal salts, higher fatty acid amides, higher fatty acid esters, glycerin esters such as triglycerides, diglycerides, monoglycerides, etc. Fatty acid-based mold release agents.

  Examples of higher fatty acids include octanoic acid, lauric acid, palmitic acid, stearic acid, 12-hydroxystearic acid, ricinoleic acid, oleic acid, behenic acid, etc., which have unsaturated bonds or hydroxy groups in the carbon chain Examples thereof include monovalent carboxylic acids having 8 or more carbon atoms, preferably 10 or more carbon atoms. Therefore, this point is also common to higher fatty acids constituting various fatty acid-based release agents.

  Examples of higher fatty acid metal salts include stearic acid, 12-hydroxystearic acid, oleic acid, octanoic acid, lauric acid, behenic acid, ricinoleic acid, and other metal salts such as calcium salts, magnesium salts, and sodium salts. Although these are mentioned, since these metal salts may affect the thermal stability and transparency of PBT, attention is required.

  Examples of higher fatty acid amides include N-unsubstituted amides such as stearic acid amide, oleic acid amide, octanoic acid amide, lauric acid amide, ricinoleic acid amide, behenic acid amide, erucic acid amide; N-oleyl palmitoamide, Examples include N-substituted amides such as N-stearyl erucamide, ethylene bis stearic acid amide, ethylene bis oleic acid amide, and methylene bis stearic acid amide.

  Examples of higher fatty acid esters include esters of these higher fatty acids with monohydric alcohols such as octyl alcohol, myristyl alcohol, stearyl alcohol, and behenyl alcohol; and esters with polyhydric alcohols such as glycols, glycerin, and pentaerythritol. It is done.

  The release agent (b) is at least one selected from a glycerin ester represented by the following formula (1) and a carboxylic acid derivative represented by the following formula (2): Particularly preferred in terms.

(In the above formula, R ¹ , R ² and R ³ each represent a hydrogen atom or an aliphatic acyl group having 8 or more carbon atoms, provided that R ¹ , R ² and R ³ are not all hydrogen atoms. R ⁴ —CO represents an aliphatic acyl group having 8 or more carbon atoms, and R ⁵ represents an alcohol residue or an amine residue.

  Specific examples of the glycerol ester represented by the above formula (1) include, for example, glycerol monostearate, glycerol distearate, glycerol tristearate, glycerol monolaurate, glycerol monooleate, glycerol dilaurate, erucic acid monoglyceride, Octanoic acid triglyceride, fatty acid (C8, C10, C12) triglyceride, fatty acid (C8, C10) triglyceride and the like can be mentioned.

  Specific examples of the carboxylic acid derivative represented by the above formula (2) include, for example, stearyl stearate, octyl palmitate, octyl stearate, lauryl laurate, behenyl behenate, cetyl myristate, 12-hydroxystearin Examples include esters such as methyl acid and ethyl 12-hydroxystearate; amides such as stearic acid amide, oleic acid amide, octanoic acid amide, lauric acid amide, ricinoleic acid amide, behenic acid amide, and erucic acid amide.

  The amount of the release agent (b) used is 0.05 to 2.5% by weight, preferably 0.08 to 2% by weight, more preferably 0.15 to 5% by weight of the resin composition constituting the PBT film of the present invention. The amount is 1.5% by weight. When the amount of the release agent (b) used is less than 0.05% by weight, the PBT film of the present invention does not provide sufficient slipperiness, whereas when it exceeds 2.5% by weight, the transparency may be impaired, There is a risk of blocking due to bleed-out.

(C) Antiblocking agent having an average particle diameter of 1 to 15 μm The antiblocking agent (c) used in the present invention is fine particles having an average particle diameter of 1 to 15 μm, preferably 5 to 15 μm.
In the present invention, it is preferable to use two or more kinds of fine particles having different average particle diameters as the antiblocking agent (c) because the friction coefficient of the unstretched PBT film can be further reduced. In this case, it is preferable that R (L) / R (S) ≧ 1.5, where R (L) is the average particle size of the larger particles and R (S) is the smaller average particle size, More preferably, R (L) / R (S) ≧ 2, more preferably R (L) / R (S) ≧ 2.5. When three or more kinds of fine particles are used, R (L) should be read as the maximum average particle diameter, and R (S) should be read as all other average particle diameters, and the relationship of the above equations must be established. Is preferred.

  The antiblocking agent (c) may be inorganic particles or organic particles. Specific examples of inorganic particles include talc, calcium carbonate, calcium oxide, zeolite, amorphous aluminosilicate, kaolin, clay, synthetic silica, titanium oxide, alumina, barium sulfate, aluminum sulfate, magnesium hydroxide and the like. The particles include talc, zeolite, amorphous aluminosilicate or synthetic silica, and particularly preferably talc or zeolite. Examples of organic particles include polymer particles of polystyrene, polyethylene, polyamide, polyester, polyacrylic ester, polymethacrylic ester, epoxy resin, polyvinyl acetate resin, polyvinyl chloride resin, or a copolymer thereof. Among the particles, cross-linked polymer particles are more preferable, and polyacrylic acid ester or polymethacrylic acid ester cross-linked polymer particles are particularly preferable. These are used individually or in mixture of 2 or more types.

  The amount of the anti-blocking agent (c) used is 0.05 to 2.5% by weight of the resin composition constituting the PBT film of the present invention, preferably 0.08 to 2% by weight, more preferably 0.1 to 0.1%. The amount is 1.5% by weight. When the amount of the anti-blocking agent used is less than 0.05% by weight, the laminated film of the present invention does not provide sufficient slipperiness, whereas when it is more than 2.5% by weight, the transparency may be impaired, or the surface There is a risk of powder blowing due to particle detachment.

Unstretched polybutylene terephthalate resin film The method of blending predetermined amounts of the above-mentioned polyester resin (a), release agent (b) and antiblocking agent (c) into a resin composition is not particularly limited. Any known method can be employed. For example, a method of adding the polyester resin (a) at the production stage, a method of dry blending the pelletized polyester resin (a), a release agent (b) and / or an anti-blocking agent for a part of the polyester resin (a) The method etc. which manufacture the masterbatch which mixed (c) with high concentration, and mix this with the remainder of a polyester resin (a) are mentioned.

  The method for producing the unstretched PBT film of the present invention is not particularly limited, and for example, a known film production technique such as a T-die method or an inflation method is applied to form a film from the resin composition. be able to. Although the thickness of a PBT film is not specifically limited, Usually, it is 1-100 micrometers, Preferably it is 2-50 micrometers, More preferably, it is 3-25 micrometers.

  The unstretched PBT film of the present invention thus obtained has excellent transparency and slipperiness. Moreover, in order to raise heat resistance, setting property, and intensity | strength, you may extend | stretch by the tenter method, the tubular method, etc.

  The unstretched PBT film of the present invention can have transparency with an L value of less than 15 in color tone measurement. When the L value exceeds 15, the film becomes cloudy and the packaged items appear dull. The L value is preferably less than 14, more preferably less than 13.

  In addition, the unstretched PBT film of the present invention can exhibit slipperiness with a dynamic friction coefficient of less than 0.40 at 23 ° C. and 65% RH. The dynamic friction coefficient is preferably less than 0.38, more preferably less than 0.35, and even more preferably less than 0.33.

Laminated film The unstretched PBT film of the present invention can be used as a single layer or a packaging material or other various applications requiring transparency and slipperiness, but the layer (A) comprising the unstretched PBT film of the present invention. The heat-sealable resin layer (C) may be laminated to form a heat-sealable laminated film. Alternatively, the unstretched PBT layer (A) may be an outermost layer, and a laminated film in which a gas barrier resin layer (B) and a heat sealable resin layer (C) are sequentially laminated may be used. The film on which the gas barrier resin layer (B) is laminated is particularly suitable as a food packaging material, and can be used in a film shape or a bag shape or other shapes.

  Examples of the resin used for the heat-sealable resin layer (C) of the laminated film of the present invention include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), polypropylene (PP), and ethylene-acetic acid. Vinyl copolymer (EVA), ethylene-methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ionomer resin, EVA saponified product, linear low density polyethylene (L-LDPE) Etc.

  The thickness of the heat-sealable resin layer is not particularly limited, but is usually 1 to 300 μm, preferably 10 to 150 μm, more preferably 30 to 75 μm.

  Examples of the resin used for the gas barrier resin layer (B) of the laminated film of the present invention include resins having a small oxygen gas permeation amount such as polyamide resin (PA) and ethylene-vinyl acetate copolymer saponified product (EVOH). . Specifically, polyamides 4, 6, 7, 8, 11, 12, 6 · 6, 6 · 10, 6 · 11, 6 · 12, 6T, 6/6 · 6, 6/12, 6 / T, 6I / 6T etc. are mentioned.

  Although the thickness of a gas barrier resin layer is not specifically limited, Usually, it is 1-100 micrometers, Preferably it is 2-50 micrometers, More preferably, it is 3-25 micrometers.

  Furthermore, the unstretched laminated film of the present invention may be provided with an adhesive layer (AC) as necessary in order to improve the adhesion between the layers (A), (B), and (C). For the adhesive layer (AC), an adhesive that improves the adhesion between the respective layers can be used, and a modified polyolefin resin (APO) is usually used.

  APO is a resin obtained by copolymerizing and / or graft-polymerizing an α, β-unsaturated carboxylic acid or a derivative thereof to a polyolefin resin mainly composed of ethylene and / or propylene. Examples of the polyolefin resin to be modified include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-sodium acrylate copolymer. A polymer etc. are mentioned. Examples of the modifying agent α, β-unsaturated carboxylic acid or derivatives thereof include acrylic acid, methacrylic acid, methyl methacrylate, sodium acrylate, vinyl acetate, maleic acid, fumaric acid, and acid anhydrides and esters thereof. .

  Although the thickness of an adhesive bond layer (AC) is not specifically limited, Usually, 1-100 micrometers, Preferably it is 2-50 micrometers, More preferably, it is 3-25 micrometers.

  The production method of the unstretched laminated film of the present invention is not particularly limited, and can be produced by employing a known film formation method such as a T-die method or an inflation method, or a lamination method. In particular, a water-cooled inflation method using a coextrusion annular die is preferable.

  This water-cooled inflation method usually uses a facility in which a water tank having a size ring inside is disposed below the annular die, and a guide plate and a winding roll are sequentially disposed below the water tank. Co-extrusion is performed so that stretching of various types of raw resin does not occur substantially, and after passing through the size ring and cooling, the cylindrical body of the laminated film is wound up by a winding roll through a guide plate. is there. The obtained film is in the form of a tube, and one end or both ends are cut into a film. Or a laminated resin bag can also be formed by heat-sealing a cylindrical body by appropriate length.

  This method has an advantage that a film can be efficiently formed by employing a co-extrusion method and a water cooling method. In addition, since the PBT layer (A) of the laminated film of the present invention contains a release agent (b) and an antiblocking agent (c) that are compatible with PBT, the PBT layer (A) is transparent even if a water cooling method is adopted. A film layer having good slipperiness is formed.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited to the following examples as long as the gist thereof is not exceeded.

The abbreviations and details of the raw materials used in the following examples are as follows.
<Raw material>
Polyester resin (a)
(1) H-PBT: Homopolybutylene terephthalate resin obtained by polymerizing terephthalic acid and 1,4-butanediol, intrinsic viscosity (IV) = 1.26 dl / g, melting point 224 ° C.
(2) S-PBT: copolymer resin of terephthalic acid, 1,4-butanediol, polytetramethylene glycol (PTMG), “Novaduran 5505S” manufactured by Mitsubishi Engineering Plastics, IV = 1.15 dl / g, Melting point 219 [deg.] C.

Gas barrier resin (3) PA6: Polyamide 6 resin, manufactured by Mitsubishi Engineering Plastics Co., Ltd., polyamide 6 extrusion grade “Novamid 1030J”.
Heat-sealable resin (4) L-LDPE: Linear low density polyethylene resin, “LF240” manufactured by Nippon Polyethylene Co., Ltd.
Modified polyolefin resin (5) APO: Modified polyolefin resin, “Modic F534A” manufactured by Mitsubishi Chemical Corporation.

Release agent (b)
(6) MG: Glycerol monostearate.
(7) TG: Glycerol tristearate.
(8) St-St: Stearyl stearate.
(9) EA: erucic acid amide.
Anti-blocking agent (c)
(10) PMMA: Polymethylmethacrylate cross-linked resin particles, average particle size 13 μm, “Epaster MA1013” manufactured by Nippon Shokubai Co., Ltd.
(11) Zeolite: Zeolite particles, average particle size 5 μm, “Silton JC50” manufactured by Mizusawa Chemical Co., Ltd.
(12) Talc: Talc particles, average particle size of 2.8 μm, “Micron White 5000” manufactured by Hayashi Kasei Co., Ltd.

Moreover, the raw material resin (PBT) shown in the following examples and the physical-property measuring method of the obtained film are as follows.
<Physical property measurement method>
(1) Thermal characteristics of PBT:
DSC curve measured using a differential scanning calorimeter “DSC220U type” manufactured by Seiko Instruments Inc. at a rate of ± 20 ° C./min at a rate of ± 20 ° C./min using about 10 mg of PBT as a sample. From this, the melting temperature was determined in accordance with JIS-K7121, and was defined as the melting point.
(2) Intrinsic viscosity of PBT:
After drying PBT at 120 ° C. for about 6 hours with hot air, using an Ubbelohde viscometer, in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 50/50 (weight ratio) at 30 ° C. In addition, the falling seconds of only the polymer solution having a concentration of 1.0 g / dL and the solvent were measured, and the intrinsic viscosity (IV) was obtained from the following formula.
IV = ((1 + 4K _H η _sp ) ^0.5 −1) / (2K _H C)
(Where η _sp = η / η ₀ −1, η is the falling seconds of the polymer solution, η ₀ is the falling seconds of the mixed solvent, and C is the concentration of the polymer solution (g / dL)) Yes, K _H is a constant of Huggins, and K _H is 0.33.)

(3) Thickness:
After cutting out the film cross section using an ultramicrotome (LEICA, ULTRACUT UCT), the layer thickness was determined by observing with a SEM (scanning electron microscope).
(4) Coefficient of dynamic friction:
Using a Toyo Seiki Co., Ltd. friction measuring machine (TR type), the dynamic friction coefficient of the film surface was measured at 23 ° C. and 65% RH in accordance with ASTM-D1894, and used as an index of slipperiness.
(5) Haze:
The haze of the film was measured using a fully automatic haze meter TC-H3DPK manufactured by Tokyo Denshoku Technical Center.
(6) L value:
Using a spectrophotometer spectrocolor meter SE2000 manufactured by Nippon Denshoku Co., Ltd., the color tone (L, A, b) of the film was measured, and the L value was displayed. In the measurement, a standard black substrate was used as a film presser.
(7) White turbidity:
The film turbidity was visually observed and evaluated according to the following criteria. In addition, there exists a tendency for L value to become large, so that the film cloudiness by visual observation is strong.
◎: There is no white turbidity and there is transparency ×: There is white turbidity
(8) Overall evaluation:
A: Excellent in transparency and slipperiness of the film and suitable for practical use.
X: At least one of transparency and slipperiness of the film is insufficient and not suitable for practical use.

[Example 1, Comparative Example 1]
After blending a polybutylene terephthalate resin with a release agent and an anti-blocking agent (also referred to as “AB agent”) in the formulation shown in Table-1 or Table-2, a twin screw extruder TEX30HCT manufactured by Nippon Steel Works ( Pellets were obtained by melt-kneading with a screw configuration = alloy, discharge rate = 15 kg / h, screw rotation speed = 200 rpm. After the pellets were dried in a hot air oven at 120 ° C. for 6 hours, a water-cooled inflation molding machine equipped with an annular die (manufactured by Ikekai Tekko Co., Ltd., screw diameter = 40 mm, L / D = 28) The solution was put into a hopper, and a water-cooled inflation film was formed under conditions of a water cooling temperature of 28 ° C. and a winding speed of 15 m / min. The extrusion resin temperature was 250 ° C., and the discharge amount was adjusted to a layer thickness of 50 μm. The obtained film was a single-layer film having a layer thickness of 50 μm, and the evaluation results are shown in Table-1 or Table-2.

[Examples 2-8, Comparative Examples 2-4]
Polybutylene terephthalate resin pellets, APO and L-LDPE obtained in the same manner as in Example 1 by dry blending a polybutylene terephthalate resin with a release agent and an AB agent in the formulation shown in Table 1 or Table 2. Each of the pellets is a water-cooled inflation molding machine equipped with a three-layer, three-layer die so as to have the layer structure shown in Table-1 or Table-2 (Ikegai Iron Works Co., Ltd., screw diameter = 40 mm, L / D = 28) was put into a hopper, and a three-layer / three-layer water-cooled inflation film was formed under conditions of a water cooling temperature of 28 ° C. and a winding speed of 15 m / min. The extrusion resin temperature was 250 ° C., and the discharge amount was adjusted to the layer thickness described in Table-1 or Table-2, and the adhesive layer (A), (C) and both layers were adhesive layers ( A laminated film having a total thickness of 80 μm was also prepared. The evaluation results of the obtained film are shown in Table-1 or Table-2.

[Example 9, Comparative Example 5]
In the formulation shown in Table-1 or Table-2, a polybutylene terephthalate resin was dry blended with a release agent and an AB agent, and polybutylene terephthalate resin pellets obtained in the same manner as in Example 1 and APO, PA6 and L- Five extruders of a water-cooled inflation molding machine (Ikegai Iron Works Co., Ltd., screw diameter = 40 mm, L / D = 28) was put into a hopper, and five kinds of five-layer water-cooled inflation films were formed under conditions of a water-cooling temperature of 28 ° C. and a winding speed of 10 m / min. In addition, extrusion resin temperature is 260 degreeC, discharge amount is adjusted so that it may become the layer thickness of Table-1 or Table-2, (A) layer is made the outermost layer, (B) layer, (C) A laminated film having a total thickness of 100 μm was prepared by sequentially laminating the layers and having an AC layer between the layers. The evaluation results of the obtained film are shown in Table-1 or Table-2.

From the results of Table-1 and Table-2, the following is found.
a) Comparison of Example 1 and Comparative Example 1 (single layer):
In Comparative Example 1 in which no release agent is used, even if the amount of anti-blocking agent (PMMA) is increased and the dynamic friction coefficient is made comparable, haze, L value, white turbidity, in all respects, compared with Example 1. Inferior, overall evaluation is inferior.
b) Comparison between Example 2 and Example 8 (Lamination A / C):
In Example 8, two types of PMMA and talc are used in combination as an anti-blocking agent. Compared with Example 2 in which only PMMA is used as the anti-blocking agent, the effect of reducing the coefficient of dynamic friction is large due to a small amount of talc.
c) Comparison between Examples 2 to 6 and Comparative Examples 2 and 3 (Lamination A / C):
In Examples 2 to 6, PMMA was used at 1.0% by weight as an anti-blocking agent, and various combinations were used as a release agent to achieve the desired effect. When the mold is not used, in Comparative Example 2, the dynamic friction coefficient is inferior only by using 1.0% by weight of PMMA. In Comparative Example 3, when PMMA is increased and the dynamic friction coefficient is made equal to that of Example 2, all of haze, L value, and white turbidity are inferior.
d) Comparison between Example 7 and Comparative Example 4 (Lamination A / C):
Example 7 uses two types of zeolite and talc as an antiblocking agent, and Comparative Example 4 is an example in which the same antiblocking agent is used and the amount of zeolite is increased and no release agent is used. The dynamic friction coefficient, haze, L value, and white turbidity are all inferior.
e) Comparison between Example 9 and Comparative Example 5 (Lamination A / B / C):
Example 9 is an example using a film in which a release agent and PMMA are used together, and Comparative Example 5 increases the amount of PMMA without using a release agent, and makes the dynamic friction coefficient equal, but haze, L Both value and turbidity are inferior.

The unstretched PBT film of the present invention can be a single layer or a laminated film laminated with a gas barrier resin layer or a heat-resistant resin layer, and is transparent and excellent in antiblocking properties, and can be widely used for packaging, decoration, and other films. Provided. In particular, a laminated resin film having a multilayer structure formed by laminating a gas barrier resin and a heat sealable resin is suitable for food packaging.

Claims (6)

(A) 95 to 99.9% by weight of a polyester resin containing a butylene terephthalate unit as a main component,
(B) A release agent having a compatibility with the polyester resin (a) 0.05 to 2.5% by weight and (c) an antiblocking agent having an average particle diameter of 1 to 15 μm 0.05 to 2.5% by weight
An unstretched polybutylene terephthalate resin film formed by forming a resin composition containing The said mold release agent (b) is at least 1 sort (s) chosen from the glycerin ester shown by the following Formula (1), and the carboxylic acid derivative shown by the following Formula (2), It is characterized by the above-mentioned. Unstretched polybutylene terephthalate resin film.

(In the above formula, R ¹ , R ² and R ³ each represent a hydrogen atom or an aliphatic acyl group having 8 or more carbon atoms, provided that R ¹ , R ² and R ³ are not all hydrogen atoms. R ⁴ —CO represents an aliphatic acyl group having 8 or more carbon atoms, and R ⁵ represents an alcohol residue or an amine residue. The anti-blocking agent (c) is composed of at least two kinds of fine particles having different average particle diameters, and the larger average particle diameter R (L) and the smaller average particle diameter R (S) have the following relationship: The unstretched polybutylene terephthalate resin film according to claim 1, wherein the unstretched polybutylene terephthalate resin film is satisfied.
R (L) / R (S) ≧ 1.5... [I]   The laminated film by which a heat-sealable resin layer (C) is laminated | stacked on the layer (A) which consists of an unstretched polybutylene terephthalate resin film of any one of Claims 1-3. (A) 95-99.9% by weight of a polyester resin containing a butylene terephthalate unit as a main component,
(B) A release agent having compatibility with the polyester resin (a) (excluding the glycerin ester represented by the following formula (1)) 0.05 to 2.5% by weight and (c) average particle diameter 1 ~ 15μm anti-blocking agent 0.05 ~ 2.5wt%
A laminated film in which an unstretched polybutylene terephthalate resin layer (A) made of a resin composition containing the outermost layer is used as an outermost layer, and a gas barrier resin layer (B) and a heat sealable resin layer (C) are sequentially laminated thereon .

(In the above formula, R ¹ , R ² and R ³ each represent a hydrogen atom or an aliphatic acyl group having 8 or more carbon atoms, provided that R ¹ , R ² and R ³ are not all hydrogen atoms. R ⁴ —CO represents an aliphatic acyl group having 8 or more carbon atoms, and R ⁵ represents an alcohol residue or an amine residue. The film according to any one of claims 1 to 5, wherein the film is formed by a water-cooled inflation method.