JP5164608B2 - Polyester film for simultaneous transfer of molding - Google Patents

Description

  The present invention relates to a polyester film for simultaneous molding transfer having excellent moldability. Specifically, the present invention relates to a polyester film for simultaneous molding and transfer that is suitable for deep drawing with a high drawing ratio because it has excellent moldability, heat resistance and transfer suitability.

  In recent years, a so-called simultaneous molding transfer method in which transfer printing is performed simultaneously with molding has become widespread as a printing method for molded products. As a film used in this method, a biaxially stretched polyester film is used from the viewpoint of properties such as strength and heat resistance.

  Recently, there is a tendency that the drawing ratio at the time of molding becomes higher and higher quality simultaneous molding transfer is required. In particular, as molded products are required to be large and have a high drawing ratio, such as refrigerator exteriors, automobile interiors, and exterior decoration applications, so advanced characteristics related to deep drawability and dimensional stability compared to conventional films Therefore, improvement of the film has been strongly desired.

  Furthermore, since it is necessary to improve the moldability of the film so as to cope with a high drawing ratio by heating immediately before the saddle shape (also referred to as preheating), the durability of the film at a high temperature is also required. Durability means that the film does not melt at the processing temperature, and that problems such as deformation and tearing of the film due to expansion of air between the mold and the film during heating do not occur.

Also, when the resin is injected after the film mold (also referred to as pre-molding), if the elastic modulus of the film is too low, the resin is rubbed between the injection resin and the film, or the film pressed against the injection resin is rubbed with the mold. This causes a problem that wrinkles enter the film and precise transfer cannot be performed. From such a viewpoint, a film having excellent transferability is desired.
JP-A 64-40400 Japanese Patent Laid-Open No. 7-196821

  The present invention has been made in view of the above-mentioned actual situation, and the problem to be solved is a biaxial structure that can simultaneously satisfy high moldability, heat resistance and transferability when used as a base material for simultaneous molding transfer. The object is to provide a stretched polyester film.

  As a result of intensive studies by the present inventors, the present inventors have found a polyester film that can solve the above problems, and have completed the present invention.

That is, the gist of the present invention includes isophthalic acid and 1,4-cyclohexanedimethanol in a total range of 10 to 30 mol% as a copolymer component other than the main constituent components, and a melting point (TmB) of 180 to 230 ° C. It is a film having a structure in which a polyester A layer containing a copolymer component other than the main constituent component and having a melting point (TmA) in the range of 200 to 255 ° C. is laminated on at least one side of the polyester B layer in the range of Each melting point difference (TmA-TmB) is 5 ° C. or more, the storage elastic modulus E ′ of the film is in the range of 400 to 1800 MPa at 80 ° C., 10 to 60 MPa at 160 ° C., and has a coating layer on at least one side. It exists in the polyester film for simultaneous transcription | transfer of the characteristics characterized by this.

Hereinafter, the present invention will be described in detail.
First, the polyester resin used in the film of the present invention will be described.
The polyester constituting the film of the present invention preferably contains terephthalic acid as a dicarboxylic acid component. Besides these, oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, One or more known dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid, diphenyl ether dicarboxylic acid, and cyclohexane dicarboxylic acid may be included as a copolymerization component. In addition, ethylene glycol is essential as a diol component. Besides these, propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, One or more known diols such as polyalkylene glycol and neopentyl glycol may be contained as a copolymerization component.

  In the present invention, the constituent components of the polyester can include various acid components and alcohol components in addition to the dicarboxylic acid component and the diol component described above. For example, monofunctional compounds such as oxycarboxylic acid such as p-oxybenzoic acid, benzoic acid, benzoylbenzoic acid, and methoxypolyalkylene glycol are used as modifying components as polyfunctional compounds such as trimesic acid, trimellitic acid, glycerin, and pentaerythritol. The functional compound can be used as a copolymerization component as long as the product polyester can hold a substantially linear polymer.

  Next, polyester obtained by polycondensation of the above-mentioned polycarboxylic acid and polyhydric alcohol is preferably used as the polyester resin constituting the A layer in the present invention. From the viewpoint of heat resistance and dimensional stability, it is necessary that ethylene terephthalate is the main constituent, and the content of the copolymer component is preferably 20 mol% or less.

  Moreover, the polyester resin which comprises B layer needs to contain 1 or more types of copolymerization components other than the main component. Polyester obtained by polycondensation of the above-mentioned polycarboxylic acid and polyhydric alcohol is preferably used, but from the viewpoint of heat resistance and dimensional stability, it is preferable that ethylene terephthalate is the main constituent, deep drawing. From the viewpoint of moldability, the copolymer component content is preferably in the range of 10 to 30 mol%. As the copolymerization component, it is particularly preferable to use isophthalic acid or 1,4-cyclohexanedimethanol, but it is not limited to this as long as it corresponds to the above-mentioned polyvalent carboxylic acid and polyhydric alcohol. The polyester resin may be a single type of copolymer in a specific range, or a polyester having a large amount of copolymerization and a polyester having a small amount of copolymerization may be mixed. In any case, it is only necessary that the content of the copolymer component and the melting point are satisfied.

  In the present invention, the melting point (TmA) of the A layer is in the range of 200 to 255 ° C., preferably in the range of 220 to 250 ° C., from the viewpoint of heat resistance, molding processability, and transferability, and the melting point of the B layer. (TmB) is in the range of 180 to 230 ° C., preferably 185 to 220 ° C., and the difference between the melting points (TmA−TmB) is 5 ° C. or more, preferably 10 ° C. or more. When the melting point of the A layer is less than 190 ° C., the heat resistance and transferability are inferior, and when the melting point of the B layer exceeds 230 ° C., the moldability and productivity are inferior. Further, when the difference between the melting points (TmA−TmB) is less than 5 ° C., the above-described moldability, productivity, heat resistance and transferability cannot be satisfied at the same time.

  In the present invention, the storage elastic modulus E 'is in the range of 400 to 1800 MPa at 80 ° C, preferably 600 to 1600 MPa, and in the range of 10 to 60 MPa, preferably 15 to 40 MPa at 160 ° C. When the storage elastic modulus is less than 400 MPa at 80 ° C. or less than 10 MPa at 160 ° C., it is inferior in heat resistance and transferability, and when it exceeds 1800 MPa at 80 ° C., or when it exceeds 60 MPa at 160 ° C., moldability, Since productivity is inferior, it is not preferable.

  In the present invention, the plane orientation coefficient ΔP of the film is usually preferably in the range of 0.020 to 0.150, and more preferably in the range of 0.030 to 0.140. When the plane orientation coefficient ΔP exceeds 0.150, the moldability tends to be inferior, and when it is less than 0.020, the heat resistance tends to be inferior.

  In the present invention, the birefringence Δn of the film is usually preferably 0.020 or less, and more preferably 0.015 or less. When Δn exceeds 0.020, the elongation at the time of molding varies, which may cause printing distortion.

  Furthermore, in the present invention, it is preferable that the heat shrinkage ratio after the heat treatment at 150 ° C. for 3 minutes is 4.0% or less both in the vertical and horizontal directions. A film having a vertical or horizontal heat shrinkage ratio exceeding 4.0% is not preferable in terms of operation because the film shrinks greatly in the heating section during the processing step.

  In the present invention, it is also preferable to add particles in order to improve the slipperiness of the film. For example, in order to improve the slipperiness of the film, the polyester composition preferably contains organic and inorganic fine particles. If necessary, an ultraviolet absorber, a colorant, an antioxidant, a surfactant, Additives such as matting agents and antistatic agents may be further blended. The fine particles imparting slipperiness are roughly classified into external particles and internal particles according to the blending method. Examples of the former include kaolin, clay, various calcium carbonates, silicon oxide, calcium terephthalate, aluminum oxide such as α-, γ-, δ-, θ-, titanium oxide, calcium phosphate, lithium fluoride, carbon black, etc. Known inert external particles may be mentioned. Examples of the latter include high-melting-point organic compounds that are insoluble during melt film formation of polyester, monodispersed spherical organic particles, pulverized organic particles, cross-linked polymers, and metal compound catalysts used during polyester synthesis, such as alkali metal compounds, Examples thereof include internal particles formed inside the polymer by the alkaline earth metal compound during the production of the polyester. These fine particles usually have a content of 0.002 to 2.0% by weight with respect to the layer constituting the surface in the film, and an average particle size in the range of 0.001 to 3.5 μm. Is preferred.

  The arithmetic average roughness Ra of the film of the present invention is preferably 40 nm or less, more preferably 35 nm or less. When Ra exceeds 40 nm, surface irregularities may be transferred to the printed layer, and the surface gloss of the molded product may be lost.

  Next, although the manufacturing method of the film of this invention is demonstrated concretely, as long as the structural requirements of this invention are satisfied, it is not limited only to the following illustrations.

  A polyester composition obtained by blending appropriate amounts of organic and inorganic fine particles as a slipping agent into a chip is dried using a commonly used dryer or vacuum dryer such as a hopper dryer, paddle dryer or oven. In the former stage, the chips are crystallized so that mutual fusion does not occur (also referred to as preliminary crystallization), and in the latter stage, the moisture content is sufficiently reduced (also referred to as main drying). After drying in this way, it is extruded into sheets at 200-320 ° C. At the time of extrusion, two or three or more polyester melt extruders can be used to form a laminated film of two layers or three or more layers by a so-called coextrusion method. As the layer structure, an A / B structure using an A raw material and a B raw material, or an A / B / A structure, and further using a C raw material to form an A / B / C structure or other film. Can do. For example, the surface shape of the A layer can be designed using specific particles as the A raw material, and a film having an A / B or A / B / A structure can be formed using a raw material not containing particles as the B raw material. In this case, since the raw material of B layer can be selected freely, a cost advantage etc. are large. Further, even if the recycled material of the film is blended with the B layer, the surface roughness can be designed by the surface A layer, so that the cost advantage is further increased. Next, the molten polymer is extruded from a die, and rapidly cooled and solidified on a rotary cooling drum so that the temperature is equal to or lower than the glass transition temperature to obtain a substantially amorphous unstretched sheet. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum. In the present invention, an electrostatic application adhesion method and / or a liquid application adhesion method is preferably employed.

  In the present invention, the unstretched sheet thus obtained is stretched biaxially to form a film. Specifically describing the stretching conditions, the unstretched sheet is stretched 2 to 6 times at 70 to 145 ° C. in the longitudinal direction to form a longitudinal uniaxially stretched film, and then 2 to 6 at 90 to 160 ° C. in the lateral direction. The film is preferably stretched twice and subjected to heat treatment at 150 to 240 ° C. for 1 to 600 seconds. Further, at this time, it is preferable to relax 0.1 to 20% in the longitudinal direction and / or the transverse direction in the maximum temperature zone of the heat treatment and / or the cooling zone at the heat treatment outlet. Further, it is possible to add re-longitudinal stretching and re-lateral stretching as necessary.

  The thickness of the film of this invention is 10-200 micrometers normally, Preferably it is 30-100 micrometers.

  The film of the present invention is usually provided with a release layer for transferring the printed layer, and this release layer exhibits adhesiveness when the printed layer is applied, and exhibits release properties when transferred. To do. When providing such a release layer, the polyester film is generally inactive and therefore has poor adhesiveness. Therefore, it is necessary to provide a coating layer for the purpose of improving the adhesion to the release layer.

  As a method for forming such a coating layer, a so-called in-line coating method in which coating is performed before the tenter entrance (before the transverse stretching step) and drying is performed in the tenter is preferable. Moreover, you may perform various coatings by offline coating after manufacture of a film as needed. Such a coat may be either single-sided or double-sided. The coating material may be either water-based or solvent-based for offline coating, but is preferably water-based or water-dispersed for in-line coating.

  The coating layer of the film of the present invention preferably comprises a combination of a crosslinking agent and various binder resins, and the binder resin is at least one selected from polyester, polyurethane and acrylic polymer from the viewpoint of adhesiveness. It is preferable to use two or more polymers in combination. Each of the above polymers may contain a derivative thereof. The derivative here refers to a polymer obtained by reacting a reactive compound with a copolymer or a functional group with another polymer. Polyvinylidene chloride, chlorinated polyolefin, etc. also form a tough film and show good adhesion to the topcoat, but these compounds contain chlorine, so they generate harmful dioxin compounds containing chlorine during combustion. This is possible and is not preferred in this respect. Further, when the scrap of the coated film is reused, there is a problem of coloring and generation of corrosive gas, which is not preferable in this respect.

  As the crosslinking agent resin, melamine-based, epoxy-based, and oxazoline-based resins are generally used, but melamine-based resins are particularly preferable from the viewpoints of coatability and durable adhesiveness. The melamine-based resin is not particularly limited, but a melamine, a methylolated melamine derivative obtained by condensing melamine and formaldehyde, a compound partially or completely etherified by reacting a methylolated melamine with a lower alcohol, and These mixtures can be used.

  The melamine-based resin may be either a monomer or a condensate composed of a multimer of dimers or a mixture thereof.

  As the lower alcohol used for the etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like can be preferably used. The functional group has an imino group, a methylol group, or an alkoxymethyl group such as a methoxymethyl group or a butoxymethyl group in one molecule, and an imino group type methylated melamine resin, a methylol group type melamine resin, or a methylol group type. A methylated melamine resin, a fully alkyl type methylated melamine resin, or the like can be used. Of these, methylolated melamine resins are most preferred. Further, an acidic catalyst such as p-toluenesulfonic acid can be used to accelerate the thermal curing of the melamine-based crosslinking agent.

  The compounding quantity of the melamine resin in a coating agent is 1 to 50 weight% normally, Preferably it is the range of 5 to 30 weight%. When the blending amount of the crosslinker resin is less than 1% by weight, the durable adhesiveness is not sufficiently exhibited, and the effect of improving the solvent resistance tends to be insufficient. There is a risk that the good adhesion will not be demonstrated.

  In the present invention, it is preferable to contain inorganic particles or organic particles in the coating layer in order to further improve the slipperiness, adhesion and the like. The amount of the particles in the coating agent is usually 0.5 to 10% by weight, preferably 1 to 6% by weight. When the blending amount is less than 0.5% by weight, the blocking resistance may be insufficient. When the blending amount exceeds 10% by weight, the sharpness of the printed layer transferred to the molded product tends to decrease.

  Examples of the inorganic particles include silicon dioxide, alumina, zirconium oxide, kaolin, talc, calcium carbonate, titanium oxide, barium oxide, carbon black, molybdenum sulfide, and antimony oxide. Among these, silicon dioxide is easy to use because it is inexpensive and has various particle sizes.

  Examples of the organic particles include polystyrene or polyacrylate polymethacrylate in which a crosslinked structure is achieved by a compound containing two or more carbon-carbon double bonds in one molecule (for example, divinylbenzene).

  The inorganic particles and organic particles may be surface-treated. Examples of the surface treatment agent include a surfactant, a polymer as a dispersant, a silane coupling agent, a titanium coupling agent, and the like.

  The coating layer may contain an antistatic agent, an antifoaming agent, a coating property improving agent, a thickener, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, a pigment, and the like.

  As long as water is the main medium, the coating agent may contain a small amount of an organic solvent for the purpose of improving dispersion in water or improving the film-forming performance. The organic solvent can be used as long as it dissolves in water. Examples of the organic solvent include aliphatic or alicyclic alcohols such as n-butyl alcohol, n-propyl alcohol, isopropyl alcohol, ethyl alcohol and methyl alcohol, glycols such as propylene glycol, ethylene glycol and diethylene glycol, n-butyl cellosolve, Glycol derivatives such as ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether, ethers such as dioxane and tetrahydrofuran, esters such as methyl acetate and amine acetate, ketones such as methyl ethyl ketone and acetone, amides such as N-methylpyrrolidone Can be mentioned. These organic solvents may be used in combination of two or more as required.

  As a coating method of the coating agent, for example, a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, or a coating apparatus other than these as shown in Yuji Harasaki, Tsuji Shoten, published in 1979, “Coating Method” Can be used.

  The coating layer may be formed only on one side or on both sides. When formed only on one side, other characteristics can be imparted by forming a coating layer different from the above-mentioned coating layer on the opposite surface as necessary. In addition, in order to improve the applicability | paintability and adhesiveness to the film of a coating agent, you may give a chemical process and an electrical discharge process to a film before application | coating. Further, in order to further improve the surface characteristics, a discharge treatment may be performed after the coating layer is formed.

  The thickness of the coating layer is usually in the range of 0.02 to 0.5 μm, preferably 0.03 to 0.3 μm, as the final dry thickness. When the thickness of the coating layer is less than 0.02 μm, the effect of the present invention may not be sufficiently exhibited. When the thickness of the coating layer exceeds 0.5 μm, the films tend to stick to each other, and particularly when the coated film is re-stretched to increase the strength of the film, it adheres to the roll in the process. There is a tendency to become easy. The above problem of sticking appears particularly when the same coating layer is formed on both sides of the film.

  According to the present invention, it is possible to provide a biaxially stretched film for molding transfer that is suitable as a base resin for a transfer foil, which can be printed finely while having sufficient molding processability. Target value is high.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist of the present invention. In addition, the measurement and evaluation method of various physical properties of a film are shown below.

(1) Melting peak temperature (Tm)
Using a differential scanning calorimeter “DSC-2920 type” manufactured by TA Instruments, a sample of 5 mg was heated from 0 ° C. to 300 ° C. at 20 ° C./min. The temperature of the endothermic peak that accompanies the melting obtained when the temperature was raised at a rate of T was defined as Tm. Among melting peak temperatures obtained by the above-mentioned method, the B layer melting point is the melting peak temperature obtained from the film obtained by removing the surface layer (A layer) of the formed film, and the A layer melting point is different from the B layer melting point. The melting peak temperature was taken.

(2) Storage elastic modulus E '
A dynamic viscoelasticity measuring device (DVA-200 type) manufactured by IT Measurement Control was used. A film having a width of 5 mm was set in a measuring device so that the gap between chucks was 20 mm, and the transition of viscoelasticity was measured at a frequency of 10 Hz while the temperature was raised from 0 ° C. to 300 ° C. at a rate of 10 ° C./min.

(3) Degree of plane orientation (ΔP), birefringence (Δn)
An Atago Abbe refractometer was used. Methylene iodide is mounted, the sample film is closely attached to the prism so that the measurement surface is down, and the refractive index nγ in the main orientation direction, using the monochromatic light sodium D line (589 nm) as the light source, and in-plane perpendicular direction to it The refractive index nβ and the refractive index nα in the thickness direction were measured. From the obtained values, the plane orientation coefficient ΔP and the birefringence Δn of the A layer were determined by the following formula. The measurement sample was collected from the center of the product master roll.
Δn = nγ−nβ
ΔP = (nγ + nβ) / 2−nα

(4) Arithmetic mean roughness (Ra)
The arithmetic average roughness Ra (μm) is used as the surface roughness. It calculated | required as follows using the Kosaka Laboratory Co., Ltd. surface roughness measuring machine (SE-3F). That is, a portion having a reference length L (2.5 mm) is extracted from the film cross-section curve in the direction of the center line, the center line of the extracted portion is the x axis, and the direction of the vertical magnification is the y axis. When represented by (x), the value given by the following equation is represented by [μm]. The arithmetic average roughness was represented by an average value of the arithmetic average roughness of the extracted portion obtained from 10 cross-sectional curves obtained from the sample film surface and obtained from these cross-sectional curves. The tip radius of the stylus was 2 μm, the load was 30 mg, and the cutoff value was 0.08 mm.

(5) Intrinsic viscosity A measurement sample was dissolved in a solvent of phenol / tetrachloroethane = 50/50 (parts by weight) to prepare a solution having a concentration c = 0.01 g / cm ³ , and a relative viscosity with the solvent at 30 ° C. η _r was measured to determine the intrinsic viscosity [η].

(6) Heat shrinkage rate In a gear oven at a temperature of 150 ± 2 ° C., a film of 10 cm in length and 10 cm in width is shrunk for 3 minutes in an unloaded state. Calculated.
Heat shrinkage = (L0−L) × 100 / L
However, L0 is the original length (cm), and L is the length after contraction.

(7) Heat resistance as a film for molding simultaneous transfer As shown in FIG. 1, a release layer, a printing layer and an adhesive layer (4) are formed on a polyester film (3), and the length is 35 cm, the width is 25 cm, and the maximum depth is Using a 3.0 cm mold (1), after preheating with an IR heater, the mold was preliminarily molded by vacuum or pressure molding. The heat resistance was evaluated according to the following criteria based on the state of melting of the film by preheating.
○: Can withstand the processing temperature and can be used for preforming △: Can be used for preforming, but rarely deforms due to film softening ×: Frequently occurs due to film melting or deformation due to film softening

(8) Formability as a film for simultaneous molding transfer When preforming was carried out by the method of (7) above, the formability was evaluated according to the following criteria by the frequency of breakage of the film by molding.
○: There is no film breakage, crack generation, etc., and the film is molded with a uniform thickness. Δ: The film is not broken, but there is a local area where the film is extremely thin. X: The film breaks frequently.

(9) Transferability as a film for molding simultaneous transfer After carrying out pre-molding by the method of (7) above, resin was injected and molding transfer was performed. The transferability was evaluated according to the following criteria depending on the state of missing or distorted patterns of printing on the obtained molded product.
○: No printing omission or distortion △: No printing omission or distortion ×: Printing omission or distortion

(10) Adhesive evaluation Using the printing ink CCST39 indigo made by Toyo Ink Co., Ltd., coated on the film surface so that the coating thickness after drying becomes 1.5 μm, dried with hot air at 80 ° C. for 1 minute, and evaluated. A film was obtained. The evaluation film was conditioned at a temperature of 23 ° C. and a humidity of 50% RH for 24 hours, and Nichiban cello tape (registered trademark) (18 mm width) was 7 cm long on the ink-coated surface of the film so that no air bubbles would enter. Then, a constant load was applied to the top with a 3 kg manual load roll. The film was fixed, one end of the cellophane tape was connected to a 500 g weight, and the weight was evaluated by a method in which a peel test in the direction of 180 ° C. was started after the distance of 45 cm naturally dropped. The adhesion was evaluated according to the following three-stage criteria.
○: Ink does not peel at all from the film surface. Δ: Ink peels from the film surface, but the peeled area is less than 10%. ×: The ink peels off at an area of 10% or more. It can be used without any problems.

Next, the polyester raw material used for an Example is demonstrated.
<Method for producing polyester (1)>
Using 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol as starting materials, 0.09 parts by weight of magnesium acetate tetrahydrate as a catalyst is placed in the reactor, the reaction start temperature is set to 150 ° C., and the methanol is distilled off gradually. The reaction temperature was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially terminated. After 0.04 part of ethyl acid phosphate was added to this reaction mixture, 0.03 part of antimony trioxide was added and a polycondensation reaction was carried out for 4 hours. That is, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.680 due to a change in stirring power of the reaction vessel, and the polymer was discharged under nitrogen pressure. The intrinsic viscosity of the obtained polyester (1) was 0.680.

<Method for producing polyester (2)>
The starting material is 100 parts by weight of dimethyl terephthalate, 54 parts by weight of ethylene glycol and 25 parts by weight of 1,4-cyclohexanedimethanol, 0.011 part by weight of tetrabutoxy titanate is used as a catalyst, and the reaction start temperature is 150 ° C. The reaction temperature was gradually increased with the distillation of methanol, and the temperature was raised to 230 ° C. after 3 hours, and the reaction was continued for another hour. Thereafter, the temperature was gradually raised from 230 ° C. and the pressure was gradually reduced from the normal pressure, and finally the temperature was 280 ° C. and the pressure was 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.70 due to a change in stirring power of the reaction vessel, and the polymer was discharged under nitrogen pressure. The intrinsic viscosity of the obtained polyester (2) was 0.700, and the content of 1,4-cyclohexanedimethanol was 33 mol%.

<Method for producing polyester (3)>
In the production method of polyester (1), after adding 0.04 part of ethyl acid phosphate, 0.3 part of silica particles having an average particle diameter of 2.2 μm dispersed in ethylene glycol and 0.03 part of antimony trioxide are added. In addition, polyester (3) was obtained using the same method as the production method of polyester (1) except that the polycondensation reaction was stopped at the time corresponding to the intrinsic viscosity of 0.610. The obtained polyester (3) had an intrinsic viscosity of 0.610.

<Method for producing polyester (4)>
In the production method of polyester (1), polyester (4) was prepared using the same method as the production method of polyester (1) except that the starting dicarboxylic acid was 80 parts by weight of dimethyl terephthalate and 20 parts by weight of dimethyl isophthalate. ) The obtained polyester (4) had an intrinsic viscosity of 0.670.

<Adjustment of coating agent>
P1-P3 aqueous coating agents were prepared by blending the aqueous paint stock solutions shown in Table 1 in the proportions shown in Table 2 below.

Example 1:
A mixed raw material in which the polyesters (3) and (4) are mixed at a ratio of 35% and 65%, respectively, is used as a raw material for the A layer, and polyesters (1), (2) and (4) are respectively 10% and 50%, The mixed raw materials similarly mixed at a ratio of 40% are supplied to the two extruders as the raw materials for the B layer, melted at 280 ° C., and then the A layer is the outermost layer (surface layer) and the B layer is the intermediate As a layer, an amorphous sheet was obtained by co-extrusion on a casting drum in a layer configuration of two types and three layers (ABA) and applying an electrostatic application method to quench and solidify. After the obtained sheet was stretched 3.4 times in the longitudinal direction at 80 ° C., the aqueous coating agent P1 shown in Table 2 was applied to one side of the longitudinally stretched film, and subsequently stretched 3.4 times in the lateral direction at 100 ° C. Then, heat treatment was performed at 182 ° C. while relaxing in the width direction of 5%. The average thickness of the obtained film was 75 μm, and the thickness of the coating layer was 0.1 μm. The properties and evaluation results of the obtained film are shown in Table 3 below.

Examples 2-5, Comparative Examples 1-5:
In Example 1, in the same manner as in Example 1, except that the polyester raw materials used in the A layer and the B layer, the blending ratio thereof, and the type of coating layer formed during film formation were changed as shown in Table 3 below. A film was obtained. The characteristics and evaluation results of the obtained film are shown in Table 4 below.

  The film of the present invention is suitable, for example, as a molding simultaneous transfer film.

It is a conceptual explanatory view of a simultaneous molding transfer device.

Explanation of symbols

1: Mold 2: Injection molding machine 3: Film 4: Layer composed of release layer, printing layer and adhesive layer

Claims (1)

The polyester B layer containing isophthalic acid and 1,4-cyclohexanedimethanol in a total range of 10 to 30 mol% and having a melting point (TmB) in the range of 180 to 230 ° C. as a copolymer component other than the main constituent components. It is a film having a structure in which a polyester A layer containing a copolymer component other than the main constituent component and having a melting point (TmA) in the range of 200 to 255 ° C. is laminated on at least one side, and the difference between the melting points (TmA− TmB) is 5 ° C. or higher, the storage elastic modulus E ′ of the film is in the range of 400 to 1800 MPa at 80 ° C., 10 to 60 MPa at 160 ° C., and has a coating layer on at least one side, Polyester film.

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