JP2005014592A - Multilayered sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a weatherproof and practically sufficiently heat resistant multilayered sheet which is capable of obtaining a good printing picture, excellent in its thermoforming nature when continuous printing is conducted and so on. <P>SOLUTION: The multilayered sheet has a surface layer consisting mainly of a substantially non-crystalline polyester resin on one side surface and a back layer mainly consisting of polycarbonate resin on the other surface with a surface layer thickness occupying the whole sheet in a ratio of 10% to 25%, containing an anti-blocking agent in the above surface layer and both surfaces are lustrous. Further, a covering layer consisting mainly of polycarbonate resin may be provided with the back payer. The ratio of the layer thickness between the surface and back layers is desirably within a range 1/9-1/3 in a case that the multilayered sheet consists of two layers, and the thickness ratio of the surface/back/covering layers is desirably 1/8/1 to 1/3/1 in such a case that the layer consists of 3 layers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a multilayer sheet, and more particularly, to a multilayer sheet that is installed on the inner front surface of a vending machine and functions as an advertising board and used for sample products such as canned beverages and cigarettes.

In recent years, instead of actual cans, vending machines have come to display as product samples what are called dummy cans that are made of film and easily lit by light from the inside. Although the dummy can has an advantage that it is easy to check a product sample even at night, when the vending machine is installed outdoors, it may be exposed to direct sunlight to cause ultraviolet deterioration. Therefore, it is required to have weather resistance that does not deteriorate against ultraviolet rays. Further, heat generated from the vending machine main body may be deteriorated by heat generated from a heater for heating a warm canned beverage, for example, so that heat resistance is required. Furthermore, since dummy cans and the like are often printed from the back side, it is required to have printability.
Known materials used for dummy cans and the like include polycarbonate single-layer sheets and polyethylene terephthalate biaxially stretched sheets (for example, Patent Document 1).

Japanese Patent Laid-Open No. 4-85693

However, since the polycarbonate single layer sheet is inferior in weather resistance, it has a drawback of yellowing when used outdoors for a long time. Polycarbonate sheets are often mirror-like on both sides, and slippage between the sheets is poor, so paper feeding for continuous printing is not performed smoothly. Also, in order to prevent the mirror surface from being damaged in the processing process, etc., there is a protective film on both sides, so it is necessary to remove one protective film during printing, and the remaining protective film must be removed during molding And workability is poor.
In addition, screen printing is generally applied to dummy cans, etc., but screen printing generally uses a slow-drying solvent, so a polycarbonate sheet causes pinholes in solid printing, and if printing is performed after thermoforming, printing is performed. Cracks sometimes occurred on the surface.

  Since a biaxially stretched sheet of polyethylene terephthalate (hereinafter referred to as stretched PET) is also a mirror surface, there is a problem that the sheets do not slide smoothly and paper feeding is not performed smoothly during continuous printing. In addition, because it is inferior in thermoformability, it can only be processed to the extent that a printed sheet is rolled into a cylindrical shape and fitted into a guide to form a simple can shape. There was a restriction that it was not possible to respond sufficiently.

  The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a good print image, excellent in automatic paper feeding properties such as when performing continuous printing, and good thermoformability. It is to provide a multilayer sheet having heat resistance and weather resistance sufficient for practical use.

The multilayer sheet of the present invention has a surface layer mainly composed of a non-crystalline polyester resin on one surface, and a back layer mainly composed of a polycarbonate resin on the other surface, The ratio of the thickness of the surface layer to the total sheet thickness is 10% to 25%, the surface layer contains an antiblocking agent, and both surfaces are glossy surfaces.
Here, the surface layer further contains polybutylene terephthalate, and the content thereof is preferably 10 to 30% by mass with respect to 90 to 70% by mass of the substantially non-crystalline polyester resin.
The multilayer sheet is a sheet having a two-layer structure including the surface layer and the back layer, and the layer thickness ratio may be in the range of surface layer / back layer = 1/9 to 1/3. .
Further, a coating layer mainly composed of a polycarbonate-based resin can be provided on the back layer.
This multilayer sheet is a sheet having a three-layer structure composed of the surface layer, the back layer, and the coating layer, and the layer thickness ratio is such that surface layer / back layer / coating layer = 1/8/1 to 1 / It can be in the range of 3/1.
The back layer can further contain a recycled resin.
Moreover, the said back layer can contain antioxidant further.
Moreover, the said coating layer can contain an antiblocking agent further.
The surface layer may further contain an antistatic agent or may be applied to the surface of the surface layer.
The multilayer sheet may have a sheet haze of 10% or less.

  According to the present invention, a good printed image can be obtained, excellent in automatic paper feeding properties such as when performing continuous printing, good thermoformability, and practically sufficient heat resistance and weather resistance. A multilayer sheet can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

The multilayer sheet of the present invention has a surface layer containing a substantially non-crystalline polyester resin as a main component on one surface (for example, the front surface side), and a polycarbonate resin on the other surface (for example, the back surface side). It has a backing layer as a main component. However, the both sides of the multilayer sheet must have a glossy finish.
Moreover, in this invention, you may have further the coating layer which has a polycarbonate-type resin as a main component on a back layer. In this case, the outermost surface of the coating layer needs to have a glossy finish.

  The multilayer sheet of the present invention needs to have a surface layer thickness of 10% to 25% with respect to the thickness of the entire sheet. If the ratio of the thickness of the surface layer to the total thickness is less than 10%, sufficient ultraviolet discoloration resistance may not be obtained, and if it exceeds 25%, sufficient heat resistance may not be obtained.

  Hereinafter, the layer structure of the multilayer sheet of the present invention will be specifically described with reference to the drawings. In addition, the same reference number is attached | subjected about the same component, and these description is abbreviate | omitted.

FIG. 1A is a diagram showing a layer configuration of a multilayer sheet according to the first embodiment of the present invention. Here, a multilayer sheet having a two-layer structure is shown, which has a surface layer 1 on the front surface side and a back layer 2 on the back surface side.
The surface layer 1 is a layer formed from a surface layer resin composition containing a substantially non-crystalline polyester resin as a main component.

  In the present invention, the polyester resin refers to a dehydration condensation product of a dicarboxylic acid and a diol. The substantially non-crystalline polyester resin used for the surface layer of the present invention has a particularly low crystallinity among so-called polyester resins, and is in contact with a slow-drying solvent used for screen printing for a long time. It means a material that does not cause white turbidity or poor fusion due to crystallization even when heat processing as performed in vacuum forming or the like is performed.

  Representative examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, adipic acid, naphthalenedicarboxylic acid and the like. Among these, terephthalic acid is preferably used, and a part of terephthalic acid may be substituted with another dicarboxylic acid. Examples of other dicarboxylic acid components include oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, neopentylic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyl ether dicarboxylic acid, p-oxybenzoic acid and the like. In addition, the other dicarboxylic acid component used may be one kind or a mixture of two or more kinds, and the amount of the other dicarboxylic acid to be substituted can be appropriately selected.

  Typical examples of the diol component include ethylene glycol, diethylene glycol, triethylene glycol, and cyclohexanedimethanol. Among these, ethylene glycol is preferably used, and a part of ethylene glycol may be substituted with other diol components. Other diol components include propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol, neopentyl glycol, polyalkylene glycol, 1,4-cyclohexanedimethanol, glycerin, pentaerythritol, trimethylolpropane, methoxy Examples include polyalkylene glycol. In addition, the other diol component used may be one kind or a mixture of two or more kinds, and the amount of the other diol to be substituted can be appropriately selected.

As the substantially non-crystalline polyester resin used in the present invention, specifically, polyethylene terephthalate obtained by condensation polymerization of terephthalic acid and ethylene glycol is preferable from the viewpoint of cost. Copolyesters containing a dicarboxylic acid component and / or a diol component other than ethylene glycol can also be used.
As the copolyester, 60 mol% or more of the dicarboxylic acid component is terephthalic acid, the dicarboxylic acid component in which the remaining dicarboxylic acid component is replaced with another dicarboxylic acid component, and 60 mol% or more of the diol component is ethylene glycol. And a copolyester obtained by condensation polymerization of a diol component in which the remaining diol component is substituted with another diol component.
The non-crystalline polyester resin in the present invention may be a mixture of polyethylene terephthalate and the above copolyester. However, when using a copolyester, care must be taken because the glass transition temperature and tensile elastic modulus of the sheet vary greatly depending on the selection and content of the copolymer component.

  Particularly preferably used as the copolyester is a substantially amorphous aromatic polyester system in which about 30 mol% to about 35 mol% of ethylene glycol in polyethylene terephthalate is substituted with 1,4-cyclohexanedimethanol. For example, a trade name “PETG” manufactured by Eastman Chemical Co., Ltd. can be obtained commercially.

In the present invention, it is preferable that the surface layer further contains polybutylene terephthalate (hereinafter sometimes abbreviated as “PBT”). However, in this case, it is necessary that amorphous polyester resin: PBT = 90 to 70% by mass: 10 to 30% by mass. In addition, the sum total of an amorphous polyester-type resin and PBT is 100 mass%. By blending PBT in the above-mentioned range in the surface layer, even if the sheets are stacked and stored after silk printing, the ink and the sheet are not blocked, and the anti-blocking property can be greatly improved. When the content of PBT is less than 10% by mass, there is no blocking improvement effect, while when it is 30% by mass or more, the surface layer is whitened by vacuum forming. As will be described later, since the multilayer sheet of the present invention is printed on the back side of the sheet and the printed image is viewed from the front side, if the surface layer is whitened, the visibility of the print applied on the back side is visible. Decreases.
The PBT used in the present invention is preferably a homopolymer, but may contain some copolymer and may have a modification rate of about 20 mol% or less. The modification rate means the sum of the mol% of dicarboxylic acid other than terephthalic acid when the total dicarboxylic acid is 100 and the mol% of diol component other than butanediol when the entire diol is 100.

  The surface layer resin composition for forming the surface layer needs to contain an antiblocking agent. Examples of the antiblocking agent used in the present invention include inorganic fillers such as spherical silica alumina, and crosslinked organic beads such as crosslinked styrene and crosslinked acrylic. Furthermore, it is preferable to blend a fatty acid ester wax obtained by esterifying montanic acid, stearic acid or the like. Here, the blending ratio of the inorganic filler and the fatty acid ester wax is preferably 5: 1 to 1: 2, for example, about 1: 1. It is preferable that the compounding quantity of an antiblocking agent exists in the range of 0.2-1.0 mass part with respect to 100 mass parts of non-crystalline polyester, for example. Thus, by mix | blending an anti-blocking agent, the slipperiness between sheets becomes good and sheet-fed printing becomes possible without a protective film. Further, the stacking resistance of the molded product is also improved.

  The surface layer may be kneaded with an antistatic agent or may be coated with an antistatic agent on the surface. Examples of the antistatic agent include glycerin ester and alkylbenzene sulfonate. The antistatic agent may be applied to the outermost surface of the other surface instead of being applied to the surface layer, or may be kneaded into the outermost layer of the other surface. Thus, by applying the antistatic agent to the outermost layer on the surface layer or the other surface, it is possible to prevent dust and the like from adhering to the multilayer sheet or the dummy can as a product. Therefore, printing omission due to adhesion of dust or the like can be prevented, and even when the product is used for a long period of time, dust or the like does not adhere and a good appearance can be maintained.

  A substantially non-crystalline polyester resin has better weather resistance than polycarbonate. Products with excellent weather resistance can be obtained by placing the surface layer containing this resin as the main component on the side exposed to sunlight. Can be realized.

  The back layer 2 is a layer formed using a back layer resin composition containing a polycarbonate-based resin as a main component. In the present invention, the polycarbonate resin means a resin composition whose main component is polycarbonate. Polycarbonate resins include those produced from bisphenol A synthesized from bisphenol and acetone by interfacial polymerization, transesterification, pyridine, etc., bisphenol A and dicarboxylic acid derivatives such as tele (iso) phthalic acid dichloride, etc. Polyester carbonate obtained by copolymerization with bisphenol A, derivatives of bisphenol A, such as those obtained by polymerization of tetramethylbisphenol A and the like.

  A recycled resin may be added to the resin composition for the back layer forming the back layer. Here, the recycled resin refers to a resin obtained by collecting trimming ears of the multilayer sheet of the present invention or a product (for example, a dummy can) formed from the sheet. Therefore, when a regenerated resin is added, a small amount of a substantially non-crystalline polyester resin is included. In addition, when adding regenerated resin, it is preferable that the addition amount is 30 mass parts or less with respect to 100 mass parts of polycarbonate-type resin.

When the recycled resin is blended with the back layer resin composition forming the back layer, it is preferable that an antioxidant is further blended. As an antioxidant used in the present invention,
Phenolic antioxidants such as pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], phosphorus such as tris (2,4-di-tert-butylphenyl) phosphite And system antioxidants. It is preferable that the compounding quantity of antioxidant exists in the range of 0.1-0.5 mass part with respect to 100 mass parts of resin compositions for back layers, for example. By blending the antioxidant, foaming and yellowing due to the ester-carbonate exchange reaction are prevented, and the recycled resin can be blended without lowering the color tone and physical properties.

  In the embodiment shown in FIG. 1 (a), the surface of the surface layer 1 and the back layer 2 has a gloss finish. In addition, printing is performed on this surface. As a printing method, silk screen printing is generally used, but is not limited to this printing method, and can be appropriately used depending on the application.

  In the multilayer sheet having a two-layer structure shown in FIG. 1A, the thickness ratio between the surface layer 1 and the back layer 2 is within the range of the thickness of the surface layer / the thickness of the back layer = 1/9 to 1/3. It is preferable that it is in the range of 1/5 to 1/3. If the thickness of the surface layer / the thickness of the back layer is less than 1/9, sufficient UV discoloration resistance may not be obtained, and if it is greater than 1/3, sufficient heat resistance may not be obtained. .

  FIG. 1B shows the layer structure of the multilayer sheet according to the second embodiment of the present invention. Here, a multilayer sheet having a three-layer structure is shown. In the embodiment shown in FIG. 1B, the back layer 2 has the surface layer 1 on one side and the coating layer 3 on the other side. Since the multilayer sheet of the present invention needs to have a glossy finish on the outermost surface, in this embodiment, the glossy finish is given to the outer surfaces of the surface layer and the coating layer.

  In the embodiment shown in FIG. 1B, the coating layer 3 is a layer formed from a resin composition containing a polycarbonate-based resin as a main component. Examples of the polycarbonate resin used here include the same resins as those listed as polycarbonate resins used for the back layer. An antiblocking agent can be added to the coating layer 3. As an antiblocking agent used here, the thing similar to what was enumerated as an antiblocking agent used for a surface layer can be mentioned. The three-layer configuration can efficiently impart slipperiness to both sides. That is, in order to give slipperiness to both sides, in the two-layer configuration shown in FIG. 1A, an antiblocking agent must be added to the thick back layer 2 in addition to the thin surface layer 1. However, in the case of the three-layer structure shown in FIG. 1B, it may be added to the surface layer 1 and the coating layer 3 having a thin layer thickness, without being added to the back layer 2 having a large layer thickness. Therefore, the latter three-layer configuration can impart slipperiness to both surfaces with a smaller amount of anti-blocking agent used than the former two-layer configuration.

  In the multilayer sheet in the embodiment shown in FIG. 1B, the thickness ratio of each layer is such that the thickness of the surface layer / the thickness of the back layer / the thickness of the coating layer = 1/8/1 to 1/3/1. It is preferable to be within the range. However, the thickness of the surface layer and the coating layer need not be the same. If the thickness ratio of each layer is less than this range, sufficient ultraviolet discoloration resistance may not be obtained, and if it exceeds, the sufficient heat resistance may not be obtained.

In the present invention, for example, in the first embodiment and the second embodiment, various layers such as an ultraviolet absorber, an antistatic agent, a dye, and an impact modifier are added to each layer constituting the multilayer sheet as necessary. Can be contained.
In addition, since the multilayer sheet of the present invention is printed on the back side of the sheet and the printed image or the like is viewed from the front side, the haze of the entire sheet is 10 so that the printed image can be clearly recognized with the naked eye. % Or less is preferable. In consideration of paper feedability during continuous printing, the friction coefficient between sheets is preferably 0.5 or less.

  The multilayer sheet of the present invention preferably has an overall thickness of 0.2 mm to 0.7 mm, and more preferably 0.4 mm to 0.6 mm. If the thickness of the multilayer sheet is less than 0.2 mm, the molded product is too weak and difficult to fit into the display stand of the vending machine. If it is thicker than 0.7 mm, the molded product has excessive quality. There is a problem that the cost of the material is increased, the molding time is prolonged, and the production efficiency is lowered.

The multilayer sheet of the present invention can set a mold temperature of a vacuum forming machine high in vacuum forming for forming a product such as a dummy can. That is, for example, a layer structure such as a layer mainly composed of a non-crystalline polyester resin / a layer mainly composed of a polycarbonate resin / a layer mainly composed of a non-crystalline polyester. In the case of the sheet having the above, sticking occurs when the mold temperature reaches about 80 ° C., but the multilayer sheet of the present invention does not stick to the mold up to about 140 ° C. Therefore, the molded product can be peeled off from the mold even after the molding without waiting for the multilayer sheet to reach a completely low temperature, that is, at a relatively high temperature before the multilayer sheet is completely lowered. Can be shortened.
In addition, in the multilayer sheet having a layer mainly composed of a substantially non-crystalline polyester resin on both sides as in the above exemplified layer configuration, the temperature of the mold cannot be set high, so at the time of molding The sheet is rapidly cooled. Therefore, the layer mainly composed of a polycarbonate resin arranged in the center is hardened before being completely molded, and the layer mainly composed of a substantially non-crystalline polyester resin on both sides having low heat resistance. Is deformed according to the shape, so it looks nicely shaped, but the shape may return when heat is applied. However, in the multilayer sheet of the present invention, since the temperature of the mold can be set high, such a problem does not occur.

Next, a method for forming the multilayer sheet of the present invention will be described below.
The multilayer sheet of the present invention is formed by, for example, a coextrusion method in which materials constituting each layer are supplied to an extruder and coextruded and laminated, a method in which each layer is formed in advance into a sheet shape, and this is laminated. However, in consideration of productivity, cost, etc., it is preferable to form by coextrusion. Specifically, first, materials such as a resin composition forming each layer can be blended and formed into pellets as necessary. These materials are put into each hopper of each extruder, melted within a temperature range of 230 ° C. to 280 ° C., coextruded, passed between mirror cast rolls, etc., and rapidly cooled and solidified to form a sheet Get.
Moreover, when forming by the method of laminating, the single-layer sheet for laminating is blended with the material for forming this single-layer sheet, pelletized as necessary, and then using a T-die extruder, A single layer sheet can be obtained by melt-extrusion within a temperature range of 230 ° C. to 280 ° C., passing between mirror-cast cast rolls, and rapidly solidifying.

  The multilayer sheet of the present invention is used after being printed and used as a dummy cigarette in a vending machine by bending, or three-dimensionally formed by thermoforming, and is suitable as a dummy can for a canned beverage in a vending machine. Used.

In the present invention, a sheet is thin by definition in JIS, and generally refers to a flat product whose thickness is small instead of length and width. By the way, a film is a thin flat product whose thickness is extremely small compared to the length and width and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll (JIS K 6900). ). Therefore, it can be said that a film having a particularly thin thickness among the sheets is a film, but the boundary between the sheet and the film is not clear and is difficult to clearly distinguish. Therefore, in the present application, the film is referred to as a “sheet”. Including “sheet” when referred to as “film”.

  EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples, and various applications are possible without departing from the technical scope of the present invention.

The evaluation methods used in the examples are shown below.
"Evaluation methods"
(1) Evaluation of automatic paper feedability The obtained sheet was subjected to an automatic screen printing machine, and the automatic paper feedability was evaluated based on the following criteria. However, for a single sheet mainly composed of a polycarbonate-based resin, a commercially available general grade was obtained, and the sheet feedability was evaluated for the sheet from which the protective film was peeled off.
The case where a sheet is smoothly fed is indicated by a symbol “○”, and a trouble such as feeding of a plurality of sheets due to poor slipping has occurred and the sheet has to be fed manually. The symbol “x” indicates.

(2) Evaluation of thermoformability A pattern was printed on the back layer or coating layer of the sheet using screen ink (trade name “VS screen ink”) manufactured by Teikoku Mfg. Co., Ltd. After printing, after drying at 60 ° C. for 20 minutes, using a vacuum forming machine, the shape of a dummy can shaped like a cylinder cut into half vertically, that is, only the front half of a real canned beverage can A shaped body of the shape was formed. At this time, the printed layer surface was set to the inside (recessed portion) of the dummy can. The sheet was preheated so that the surface temperature was 170 ° C.
The thermoformability and pattern transparency were evaluated based on the following criteria.

Evaluation criteria:
As for “thermoformability”, the sign “X” indicates that the sheet has a large drawdown during preheating and is difficult to form, and the sign “◯” indicates that the sheet can be formed without any problem.
About "picture transparency", the printed picture was visually observed from the surface layer side and evaluated based on the following criteria. The symbol “○” indicates that the gloss of the pattern is good and the solid printing surface has no ink repellency, and the symbol indicates that the gloss of the pattern is inferior or solid printing has been repelled. Indicated by “x”.

(3) Evaluation of heat resistance What was shaped into a dummy can shape was placed in an oven at 100 ° C. and left for 6 hours. The appearance of the dummy can after observing was observed, and the symbol “◯” indicates that no deformation was observed, and the symbol “×” indicates that the deformation was observed.

(4) Evaluation of weather resistance A sample piece having a size of 4.0 cm × 6.5 cm is cut out from the one formed into a dummy can shape, and ultraviolet rays are irradiated from the surface layer side in an atmosphere of 63 ° C. using a sunshine weather meter. Irradiated for 250 hours. The color tone of the pattern before and after irradiation with ultraviolet rays was visually evaluated. The symbol “X” indicates that the color tone is clearly different before and after the ultraviolet irradiation, and the symbol “◯” indicates that the color tone is hardly recognized. In consideration of the fact that it is printed on the back of the sheet and the thickness of the sheet, it is considered that the color tone change of the pattern is not due to the discoloration of the ink but due to the discoloration of the sheet. .

(5) Evaluation of blocking resistance of sheet after printing After printing a pattern on the back layer of the sheet using screen ink “VS screen ink” manufactured by Teikoku Mfg. Co., Ltd., the sheet is dried at 60 ° C. for 20 minutes. . After 2,000 sheets were stacked and allowed to stand for one week, several sheets were taken out from the lowermost side, and the blocking state of the printed sheets was evaluated based on the following evaluation criteria. The evaluation standard is that the ink is partially transferred to the non-printing surface of another sheet that is in contact with the printing surface. The symbol “Δ” indicates that no transition is observed, and the symbol “◯” indicates that the material is easily removed without sound.

(6) Evaluation of sheet whitening The molded product in the shape of a dummy can prepared in the same manner as in the evaluation of (2) thermoformability was observed with the naked eye from the surface layer side. The symbol “X” indicates that the surface layer is slightly white, and symbol “◯” indicates that the pattern printed on the back is clearly visible through the sheet.

(Example 1)
As the resin composition for the surface layer, the average particle diameter is 100 parts by mass of a substantially non-crystalline polyester resin (trade name “PETG6763” manufactured by Eastman Chemical Co., Ltd., and “PETG” in the table). 0.5 parts by mass of 7 μm spherical silica alumina, 0.3 parts by mass of the product name “Rico Wax E” manufactured by Clariant Japan Ltd. as a fatty acid ester wax, and a polycarbonate resin (Mitsubishi) “Novalex 7027IR” manufactured by Engineering Plastics Co., Ltd., represented as “PC” in the table) was used. These resins were respectively put into the hoppers of two extruders, melted at a temperature of 260 ° C., then coextruded using a multi-manifold die, and then passed between a pair of mirror-finished rolls to be cooled and solidified. . The obtained sheet was a two-type two-layer sheet having a total thickness of 0.5 mm and a thickness ratio of surface layer / back layer = 1/4, and both surfaces were gloss-finished.
The obtained multilayer sheet was evaluated for automatic paper feedability, thermoformability, pattern transparency, heat resistance and weather resistance. The results are shown in Table 1.

(Examples 2 to 4)
In Example 1, as shown in Table 1, the thickness ratio of the surface layer and the back layer was the same as that of Example 1 except that the surface layer / back layer was changed to 1/9, 1/5, and 1/3, respectively. Thus, multilayer sheets having total sheet thicknesses of 0.2 mm, 0.4 mm, and 0.7 mm were obtained.
The obtained multilayer sheet was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)
As shown in Table 1, a substantially non-crystalline polyester resin (trade name “PETG6763” manufactured by Eastman Chemical Co., Ltd.) similar to Example 1 was used as the surface layer resin, and the resin composition for the back layer was used. , 84.4 parts by mass of polycarbonate resin (“Novalex 7027IR” manufactured by Mitsubishi Engineering Plastics), 0.3 part by mass of “Irganox 1010” manufactured by Ciba Geigy as a phenolic antioxidant, and phosphorus-based oxidation As an inhibitor, 0.3 part by mass of “Irgaphos 168” manufactured by Ciba Geigy Corporation and 15 parts by mass of recycled resin were used. These resins were put into the hoppers of two extruders in the same manner as in Example 1, and a multilayer sheet was produced in the same manner as in Example 1.
The obtained multilayer sheet was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)
A multilayer sheet was produced in the same manner as in Example 1 except that “Colcoat WAS-15X” manufactured by Colcoat Co. was applied as a nonionic antistatic agent on the surface of the surface layer.
The obtained multilayer sheet was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
A commercially available general grade was used as a single layer sheet mainly composed of a polycarbonate resin. About this single-layer sheet, the protective film of one side was peeled off and the same evaluation as Example 1 was performed. The results are shown in Table 1.

(Comparative Example 2)
It comprises 90.2 mol% terephthalic acid as the dicarboxylic acid component, 9.8 mol% isophthalic acid, 98 mol% ethylene glycol and 2 mol% diethylene glycol as the diol component, and contains spherical silica having an average particle size of 0.8 μm. ] = 0.70, Tg = 66 ° C. Copolyester was pre-crystallized with a paddle dryer, followed by main drying, extrusion from an extruder at 260 ° C., and rapid cooling and solidification to obtain an unstretched film. The resulting unstretched film was stretched 1.2 times in the machine direction using a 80 ° C. stretch roll, and continuously relaxed 0.90 times between the 80 ° C. stretch roll and the cooling roll without cooling. . Next, this film was guided to a tenter, stretched 3.2 times in the transverse direction at 78 ° C., heat-treated at 80 ° C., and then cooled to obtain a stretched PET film having an average thickness of 225 μm.
The stretched PET sheet was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
A multilayer sheet in the same manner as in Example 1 except that the thickness of the surface layer / the thickness of the back layer is changed to 1/10 (the thickness of the surface layer is 9% with respect to the total sheet thickness). Was made.
The obtained multilayer sheet was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
A multilayer sheet in the same manner as in Example 1, except that the thickness of the surface layer / the thickness of the back layer in Example 1 was changed to 1/2 (the thickness of the surface layer relative to the total sheet thickness was 33%). Was made.
The obtained multilayer sheet was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 7)
As a resin composition for the surface layer, 100 parts by mass of a substantially non-crystalline polyester resin (trade name “PETG6763” manufactured by Eastman Chemical Co., Ltd.) and 0.5 μm of spherical silica alumina having an average particle diameter of 7 μm are used. 0.3 parts by mass of the product name “Rico Wax E” manufactured by Clariant Japan Co., Ltd. as the fatty acid ester wax, and polycarbonate resin (“NOVAREX 7027IR manufactured by Mitsubishi Engineering Plastics Co., Ltd.) as the back layer resin composition. )) And a polycarbonate resin (“Novalex 7027IR” manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was used as the resin composition for the coating layer. These resins were respectively put into the hoppers of two extruders, melted at a temperature of 260 ° C., then coextruded using a multi-manifold die, and then passed between a pair of mirror-finished rolls to be cooled and solidified. . The obtained sheet was a two-layer / three-layer sheet having a total thickness of 0.5 μm and a thickness ratio of surface layer / back layer / coating layer = 1/4/1, and both surfaces were glossy finished. .
About the obtained multilayer sheet, it carried out similarly to Example 1, and evaluated automatic paper-feeding property, thermoformability, pattern transparency, heat resistance, and weather resistance. The results are shown in Table 2.

(Examples 8 to 10)
In Example 7, as shown in Table 2, the thickness ratio of the surface layer, the back layer, and the coating layer was as follows: surface layer / back layer / coating layer = 1/8/1, 1/5/1, 1/3 / A multilayer sheet was obtained in the same manner as in Example 7 except that it was changed to 1.
The obtained multilayer sheet was evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Example 11)
As shown in Table 2, a substantially non-crystalline polyester resin (trade name “PETG6763” manufactured by Eastman Chemical Co., Ltd.) similar to Example 7 was used as the surface layer resin, and the resin composition for the back layer was used. 84.4 parts by mass of polycarbonate resin (“Novalex 7027IR” manufactured by Mitsubishi Engineering Plastics), 0.3 part by mass of “Irganox 1010” manufactured by Ciba Geigy as a phenolic antioxidant, and phosphorous antioxidant 0.3 parts by mass of “Irgaphos 168” manufactured by Ciba Geigy Co., Ltd. and 15 parts by mass of recycled resin, and polycarbonate resin (“Novalex 7027IR” manufactured by Mitsubishi Engineering Plastics) as a coating layer resin Using. These resins were respectively put into hoppers of three extruders, melted at a temperature of 260 ° C., and then coextruded using a multi-manifold die, and then passed between a pair of mirror surface rolls to be cooled and solidified. The obtained sheet was a three-layer three-layer sheet having a total thickness of 0.5 μm and a thickness ratio of surface layer / back layer / coating layer = 1/4/1, and both surfaces were gloss-finished. .
The obtained multilayer sheet was evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Example 12)
As a resin composition for the coating layer, polycarbonate resin (“NOVALEX 7027IR” manufactured by Mitsubishi Engineering Plastics Co., Ltd.) is used in 100 parts by mass, spherical silica alumina having an average particle size of 7 μm, 0.5 parts by mass, and fatty acid ester type. The same procedure as in Example 7 was performed except that 0.3 parts by mass of “Lico Wax E” manufactured by Clariant Japan Co., Ltd. was used as the wax. These resins and the like were respectively put into hoppers of three extruders, melted at a temperature of 260 ° C., and then co-extruded using a multi-manifold die, and then passed between a pair of mirror surface rolls to be cooled and solidified. . The obtained sheet was a three-layer three-layer sheet having a total thickness of 0.5 μm and a thickness ratio of surface layer / back layer / coating layer = 1/4/1, and both surfaces were gloss-finished. . The obtained multilayer sheet was evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Example 13)
In Example 12, a multilayer sheet was produced in the same manner as in Example 12 except that “Colcoat WAS-15X” manufactured by Colcoat was applied as a nonionic antistatic agent on the surface of the surface layer. The obtained sheet was a three-layer three-layer sheet having a total thickness of 0.5 μm and a thickness ratio of surface layer / back layer / coating layer = 1/4/1, and both surfaces were gloss-finished. . The obtained multilayer sheet was evaluated in the same manner as in Example 1. The results are shown in Table 2.

As is clear from Table 1 and Table 2, the multilayer sheets of the present invention of Examples 1 to 13 are all in automatic paper feeding property, thermoformability, pattern transparency, heat resistance, and weather resistance. Excellent results were obtained. In Examples 12 and 13 in which the anti-blocking agent was added to the coating layer in a three-layer structure, the paper feeding property was superior to the other examples. In Examples 6 and 13 in which an antistatic agent was applied to the surface layer, there was no printing omission due to adhesion of dust or the like, and there was no adhesion of dust or the like even after 6 months from commercialization, and excellent antistatic It was found to be effective. In addition, the multilayer sheets of Examples 1 to 13 had a haze of less than 10%.
On the other hand, Comparative Example 1, which is a single-layer sheet mainly composed of a polycarbonate-based resin, has problems in automatic feeding properties and weather resistance. Further, Comparative Example 2, which is a stretched PET single-layer sheet, has a problem in automatic paper feeding properties and thermoformability.

(Example 14)
In Example 1, trade name “Toughpet N1000” (glass transition temperature 60 ° C.) manufactured by Mitsubishi Rayon Co., Ltd. was further blended as PBT on the surface layer, and as shown in Table 3, PETG / PBT / inorganic filler / wax = 90. A multilayer sheet having a two-layer structure was formed in the same manner as in Example 1 except that the mass was changed to 10 parts by mass / 0.5 parts by mass / 0.3 parts by mass.
About the obtained multilayer sheet, the blocking resistance of the sheet after printing and the whitening of the sheet were evaluated. The results are shown in Table 3.

(Example 15)
In Example 1, PBT was further blended in the surface layer, and as shown in Table 3, changed to PETG / PBT / inorganic filler / wax = 70 parts by mass / 30 parts by mass / 0.5 parts by mass / 0.3 parts by mass. A multilayer sheet having a two-layer structure was formed in the same manner as in Example 1 except that.
About the obtained multilayer sheet, the blocking resistance of the sheet after printing and the whitening of the sheet were evaluated. The results are shown in Table 3.

(Comparative Example 5)
In Example 1, PBT was further blended in the surface layer, and as shown in Table 3, changed to PETG / PBT / inorganic filler / wax = 65 parts by mass / 35 parts by mass / 0.5 parts by mass / 0.3 parts by mass. A multilayer sheet having a two-layer structure was formed in the same manner as in Example 1 except that.
About the obtained multilayer sheet, the blocking property of the sheet and the whitening of the sheet were evaluated. The results are shown in Table 3.

  In addition, the multilayer sheet obtained in Example 1 was also evaluated for sheet blocking properties and sheet whitening. The results are shown in Table 3.

  As is apparent from Table 3, it was found that the sheet containing a predetermined amount of PBT in the surface layer is a sheet that is extremely excellent in blocking resistance of the printed sheet and does not cause whitening.

(A) is a figure which shows the layer structure of the multilayer sheet which concerns on the 1st Embodiment of this invention, (b) is a figure which shows the layer structure of the multilayer sheet which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

1 Surface layer 2 Back layer 3 Substrate layer

Claims (10)

  An entire sheet having a surface layer mainly composed of a non-crystalline polyester resin on one surface and a back layer mainly composed of a polycarbonate resin on the other surface. A multilayer sheet, characterized in that the proportion in the thickness is 10% to 25%, the surface layer contains an antiblocking agent, and both surfaces are glossy surfaces.   The surface layer further contains polybutylene terephthalate, and the content thereof is 10 to 30% by mass with respect to 90 to 70% by mass of the substantially non-crystalline polyester resin. The multilayer sheet as described.   2. A sheet having a two-layer structure comprising the front layer and the back layer, wherein the layer thickness ratio is in the range of 1/9 to 1/3. Or the multilayer sheet of 2.   The multilayer sheet according to claim 1, further comprising a coating layer mainly composed of a polycarbonate-based resin on the back layer.   A sheet having a three-layer structure composed of the surface layer, the back layer, and the coating layer, wherein the layer thickness ratio is in the range of surface layer / back layer / coating layer = 1/8/1 to 1/3/1. The multilayer sheet according to claim 4, wherein the multilayer sheet is inside.   The multilayer sheet according to any one of claims 1 to 5, wherein the back layer further contains a recycled resin.   The multilayer sheet according to claim 6, wherein the back layer further contains an antioxidant.   The multilayer sheet according to any one of claims 1 to 7, wherein the coating layer further contains an antiblocking agent.   The multilayer sheet according to any one of claims 1 to 8, wherein the surface layer further contains an antistatic agent or is applied to a surface of the surface layer.   The multilayer sheet according to any one of claims 1 to 9, wherein the haze of the sheet is 10% or less.

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