JP2018047938A - Food container and method for manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable printing having glossiness and extreme high euphemism property on a molded container such as a tray, a bowl or the like for storing food.SOLUTION: A food container has a base material film layer/an ink layer/a tin vapor-deposited layer/a base material sheet layer, and the base material film layer comprises an A-PET film, a biaxial drawing PP film or a biaxial drawing PS film. The tin vapor-deposited layer is deposited in a discontinuous island structure, a size of an island of the island structure 200Å to 10,000Å, a space between the islands is 100Å to 5,000Å, and a light transmittance of the island structure is 1% to 15%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to food containers such as trays and baskets for storing food, and more specifically, by printing on a substrate film having a smooth surface and by providing tin vapor deposition in close contact with the back side of the printed layer, The present invention relates to a food container that can be printed and a manufacturing method thereof.

  In recent years, foods such as supermarkets and convenience stores have been sold in food containers such as plastic trays and baskets. Among these food containers, trays for vegetables, fish, fruits, etc. that do not contain oil and are not heated are mostly plain foam PS trays that are not printed. However, cooked foods, especially bento lunchboxes, New Year dishes, and delivery bowls. In order to improve the appearance, the tray used for the above is printed.

  In order to provide printing on such a tray, it is common to first print on a plastic film and paste this printing film on a sheet as a base material. However, if the base sheet is transparent, it is transparent. The color looked light, and when the base sheet was colored, it was affected by the color. In order to show the color tone of printing well, when printing on a plastic film, it can be carried out by giving a solid white printing on the last printing plate, or by kneading a white pigment in a sheet. However, such a method could not give metallic luster.

  As a method for imparting a metallic luster, there is a method in which an Al vapor-deposited film is bonded to a printing film, and a method using this Al vapor-deposited film has been mainly used for food packaging of bags. Al vapor deposition is capable of obtaining an excellent metallic luster by total reflection of all rays as used in mirrors and the like, but it is continuously vapor deposited on the entire surface of the film even if the amount of vapor deposition is reduced. Therefore, electrical insulation cannot be imparted to food packaging bags using an Al vapor-deposited film, and as a result, it cannot be used for a microwave oven, and a metal detector used for foreign object detection can also be used. I could not do it.

  In addition, when the Al vapor-deposited film is bonded to a base material sheet and used for a molded food container, when the base sheet to which the Al vapor-deposited film is bonded is formed into a container, the Al vapor-deposited layer is stretched. There was a drawback that the Al vapor deposition layer was rough and became frosted and lost its metallic luster.

  On the other hand, there has been proposed a “deposition film for packaging” characterized by having microwave permeability, electrical insulation, and metallic luster (see Patent Document 1). In the present invention, Sn is vapor-deposited on a plastic film, and if the light transmittance is 1% to 15%, the deposited Sn has an island-like structure. It is to have.

JP 63-157853 A

  However, even when the vapor deposition film for packaging proposed in Patent Document 1 is used, when used in a molded container, a glossy printed appearance cannot always be obtained.

  An object of the present invention is to solve the above problems and to provide a food container that is glossy and has an extremely high nickname when printed on a molded container, and a method for producing the same.

  As a result of earnest research to solve the above-mentioned problems, the present inventors have found that when the surface of the film to be printed is extremely smooth, a glossy appearance can be obtained without any defects such as matting, The present invention has been completed by finding that when a tin-deposited film is laminated on the back side of a printed ink layer, printing is reflected and a more glossy appearance can be obtained.

  The food container according to claim 1 has a base film layer / ink layer / tin deposited layer / base sheet layer, and the base film layer is an A-PET film, a biaxially stretched PP film, or a biaxially stretched film. The film is a PS film, and the tin deposition layer is deposited on a discontinuous island structure, and the island size of the island structure is 200 mm to 10,000 mm, and the distance between the islands is 100 mm to 5,000 mm. The light transmittance is 1% to 15%.

  The food container according to claim 2 is characterized in that the tin vapor deposition layer is vapor deposited on an ink layer.

  The food container according to claim 3 is characterized in that the tin vapor-deposited layer is vapor-deposited on a vapor deposition film, and the tin vapor-deposited layer and the ink layer are bonded by dry lamination.

  The food container according to claim 4 is characterized in that the vapor deposition film is a CPP film or an unstretched PS film.

  The food container according to claim 5 is configured such that the base sheet layer is a PP sheet, a talc-containing PP sheet, a foamed PP sheet, a talc-containing PET sheet, a foamed PS sheet, or a heat-resistant foamed PS sheet. Yes.

  The method for producing a food container according to claim 6 prints an ink layer by gravure printing on a base film, coats an anchor coat layer for vapor deposition on the ink layer, and applies a tin vapor deposition layer to the anchor coat layer, A printing / tin deposition laminated film consisting of a substrate film layer / ink layer / anchor coat layer / tin deposition layer is prepared, and the tin deposition layer and the substrate sheet of the printing / tin deposition laminate film are laminated by dry lamination. After producing a molding laminate comprising a substrate film layer / ink layer / anchor coat layer / tin vapor deposition layer / dry laminate adhesive layer / substrate sheet layer, and heating the molding laminate to a predetermined temperature, The container is formed by vacuum or vacuum / pressure forming machine.

  The method for producing a food container according to claim 7 includes printing an ink layer by gravure printing on a base film, coating an evaporation anchor coat layer on the evaporation film, and then forming a tin vapor deposition layer on the anchor coat layer. The ink layer and the tin vapor deposition layer are laminated by dry lamination, and printing / tin vapor deposition lamination is made up of base film layer / ink layer / dry laminate adhesive layer / tin vapor deposition layer / anchor coat layer / vapor deposition film layer A film is prepared, and the film layer for vapor deposition of the printing / tin vapor deposition laminated film is superposed on the substrate sheet immediately after extrusion to form the substrate sheet, and heat-laminated by heat at the time of extrusion to form a substrate A laminate material for molding consisting of a film layer / ink layer / dry laminate adhesive layer / tin deposited layer / anchor coat layer / deposited film layer / substrate sheet layer was prepared, After the molding laminate was heated to a predetermined temperature, and is configured as characterized in that molded into the container by the vacuum or vacuum-pressure forming machine.

  The method for producing a food container according to claim 8 prints an ink layer by gravure printing on a base film, coats an anchor coat layer for vapor deposition on the vapor deposition film, and then forms a tin vapor deposition layer on the anchor coat layer. The ink layer and the tin vapor deposition layer are laminated by dry lamination, and printing / tin vapor deposition lamination is made up of base film layer / ink layer / dry laminate adhesive layer / tin vapor deposition layer / anchor coat layer / vapor deposition film layer A film is prepared, and on the other hand, a foam base material sheet is prepared separately, and the film layer for vapor deposition of the printing / tin vapor deposition laminated film is superimposed on the preheated foam base material sheet, and the printing / tin vapor deposition laminated film side And then heated and bonded with a hot roll to form a base film layer / ink layer / dry laminate adhesive layer / tin deposition layer / anchor coat layer / deposition film layer / To prepare a molding laminate material composed of a Awamotozai sheet layer is composed after heating the molded laminate for a predetermined temperature, as characterized by forming the container by vacuum or vacuum-pressure forming machine.

  In the food container according to claim 1, the base film is provided with an ink layer, and the base film is the surface side of the food container (the surface side of the food container normally seen by food eaters). In the case of a tray or the like, it is on the inner surface side, and in the case of a bowl or cup, it is on the outer surface side.) Therefore, the light beam reflected by the ink layer passes through the base film and goes out of the food container from the surface. By the way, the substrate film is an A-PET film, a biaxially stretched PP film or a biaxially stretched PS film, and these films have extremely high smoothness. Therefore, the light reflected by the ink layer of the pattern, characters, color, etc., and the reflected light of the metallic luster of the tin vapor deposition layer in the blank area where there is no printing is not disturbed on the surface of the substrate film. A glossy and high-quality cosmetics can be obtained.

  A tin vapor deposition layer is laminated on the ink layer, so that printing of pictures, letters, etc. can be seen, and tin-deposited metallic luster can be seen in the part without printing, so the container as a whole has a high-class aesthetics It is excellent.

  The tin vapor deposition layer is deposited on a discontinuous island structure, and the island size of the island structure is 200 mm to 10,000 mm, and the distance between the islands is 100 mm to 5,000 mm. Since it has electric insulation, it can be heated in a microwave oven, and a metal detector can also be used.

  The base sheet layer can secure rigidity and maintain the container shape.

  In the food container according to claim 2, when the ink layer and the tin vapor deposition layer are formed by being laminated, the base film layer / ink layer / tin vapor deposition layer is obtained by directly depositing the tin vapor deposition layer on the ink layer. It has a laminated structure. Therefore, a tin vapor deposition layer can be closely provided on the back side of the ink layer.

  In the food container according to claim 3, when the ink layer and the tin vapor deposition layer are laminated and formed, the tin vapor deposition layer is formed on the vapor deposition film, and the tin vapor deposition layer and the ink layer are bonded by dry lamination. By doing so, it becomes a laminated structure which becomes a base film layer / ink layer / tin deposited layer / deposited film layer. Therefore, a tin vapor deposition layer can be closely provided on the back side of the ink layer.

  In the food container according to the fourth aspect, since the vapor deposition film layer is formed of a CPP film or an unstretched PS film, the same kind of substrate is used when a laminated material for molding is produced by laminating with a base sheet. When the material sheet is extruded, it can be heat-bonded by heat at the time of extrusion, and when the substrate sheet is a foamed substrate sheet, it can be heat-bonded with a heat roll.

  In the food container according to claim 5, since the base sheet layer is formed of PP sheet, talc-containing PP sheet, talc-containing PET sheet or heat-resistant foamed PS sheet, it can be used for heating by a microwave oven, It can also be used for food containers that require rigidity. In the case of a foamed PP sheet or a heat-resistant foamed PS sheet, a food container can be directly held by hand even if the food is hot.

  In the method for producing a food container according to claim 6, an ink layer is printed on the base film by gravure printing, an anchor coat layer for vapor deposition is coated on the ink layer, and a tin vapor deposition layer is applied to the anchor coat layer. Therefore, a tin vapor deposition layer can be easily and closely laminated on the back side of the ink layer. Moreover, since the tin vapor-deposited layer of the printing / tin vapor-deposited laminated film and the base sheet are laminated by dry lamination, a molding laminate can be easily produced.

  In the manufacturing method of the food container which concerns on Claim 7, after printing an ink layer by gravure printing on a base film, and coating the anchor coat layer for vapor deposition on the vapor deposition film, a tin vapor deposition layer is formed on the anchor coat layer. Since the ink layer and the tin vapor deposition layer are laminated by dry lamination, the tin vapor deposition layer can be easily and closely laminated on the back side of the ink layer. In addition, the film layer for vapor deposition of the printing / tin vapor deposition laminated film is superposed on the base sheet immediately after being extruded to form the base sheet, and is thermally bonded by heat at the time of extrusion. It can be easily manufactured.

  In the manufacturing method of the food container which concerns on Claim 8, after printing an ink layer by gravure printing on a base film, and coating the anchor coat layer for vapor deposition on the vapor deposition film, it is a tin vapor deposition layer on this anchor coat layer. Since the ink layer and the tin vapor deposition layer are laminated by dry lamination, the tin vapor deposition layer can be easily and closely laminated on the back side of the ink layer. In addition, the film layer for vapor deposition of the printing / tin vapor deposition laminated film is superposed on the preheated foam base material sheet, and it is heat bonded from the printing / tin vapor deposition laminated film side with a hot roll, so that the molding laminated material is It can be easily manufactured.

Electron micrograph of tin deposited layer Schematic diagram of substrate sheet manufacturing equipment Schematic diagram of a laminating device for molding laminates Top view of female aluminum mold for tray Schematic diagram of a laminating device for molding laminates

  The food container of the present invention has a base film layer and an ink layer, that is, the ink layer is formed by printing on the base film. This base film is an A-PET film, a biaxially stretched PP film, or a biaxially stretched PS film. Since these films are extremely smooth, the pattern of the ink layer is a glossy pattern, etc. Visible to.

  That is, the visual recognition of the ink layer printed on the base film is such that the light beam reflected by the ink layer is transmitted through the base film and comes out from the surface of the base film (the surface of the food container). . Therefore, when the surface of the substrate film is not smooth, the light beam reflected by the ink layer is disturbed by the unevenness of the surface of the substrate film and becomes frosted. Therefore, in the present invention, the substrate film capable of exhibiting a glossy appearance has been intensively studied, and the A-PET film, the biaxially stretched PP film and the biaxially stretched PS film have been found to be extremely good. It is a thing.

  When the base film is formed into a food container, the base film is disposed on the innermost surface side in a tray or the like, and is disposed on the outermost surface side in a bag or cup. In the case of a tray or the like, since it comes into direct contact with food, biaxially stretched OPP film or unstretched A-PET film is used in the case of food that contains oil and is heated in a microwave oven. Biaxially stretched OPS is used for foods that are not heated.

  In the food container of the present invention, a tin vapor deposition layer is laminated on the ink layer, and by laminating the tin vapor deposition layer, the original color of the ink can be reproduced as it is, and the appearance of printing is improved. Can do.

  In other words, visible light consists of seven colors of red, orange, yellow, green, blue, indigo, and purple, and the printed red is reflected only by the red pigment and the other colors. The rays of light are absorbed and appear red. Similarly, the purple color is reflected only by the purple pigment, and the other color rays are absorbed and appear purple. It turns white when all light rays are diffusely reflected, and turns black when all light rays are absorbed. Although the mirror is totally reflected, the light beam is normally reflected as it is without being disturbed, so it becomes a mirror surface instead of white.

  To improve the appearance of printing, it is necessary to reproduce the original color of the ink as it is, but in the case of food containers, printing of patterns, etc. is usually applied to a transparent film, and the transparent film is used as a sheet. In many cases, printing is performed by pasting. However, when printing is performed on a transparent film, the original color cannot be reproduced with a pigment concentration suitable for printing, and it often appears transparent. In order to make up for this, white solid printing is performed on the last printing plate, but this also has a limit. In the present invention, instead of the white solid printing, a tin vapor deposition layer is applied to improve the appearance and to obtain a metallic luster in the non-printed portion.

  In other words, since the tin vapor deposition layer, which is a mirror surface, is arranged on the back side of the ink layer, the transmitted light that has passed through the transparent ink layer is also transmitted light having the same color as the color of the ink layer (reflected light). Since it is normally reflected by the mirror surface of the layer, the reflected light of the ink layer and the reflected light of the tin vapor deposition layer go out to the outside of the container, so the color of the pattern increases and the original color is obtained. In addition, the portion without the ink layer is totally reflected by the mirror surface of the tin vapor deposition layer and becomes a silvery metallic luster, which can give a high-class feeling.

  Tin deposition is said to be nucleation → nuclear fusion → initial island structure → island structure → continuous deposition layer based on the relationship between tin cohesive energy and film adsorption energy, and continuous when the light transmittance is less than 1%. It becomes a vapor deposition layer, and it becomes an island structure at 1% or more. FIG. 1 shows an electron micrograph (50,000 times magnification) of an island structure having a light transmittance of 11.5%. On the other hand, when the light transmittance is 15% or more, the island-like interval is separated, the metallic luster on the appearance is lost, and the high-class feeling is lost.

  The distance between the islands of such island-like structures is 100 mm to 5,000 mm, and these ranges are smaller than the inside and outside of the microwave wavelength of 10 cm, and microwaves can be transmitted, so that microwave heating can be performed. Therefore, it is possible to use the metal detector without causing electromagnetic induction which is the principle of the metal detector.

  In addition, island-like structure cannot be taken in other metal vapor deposition represented by Al vapor deposition other than tin vapor deposition, and since it becomes a continuous vapor deposition layer from the beginning, it does not transmit microwaves and has no electrical insulation. Microwave heating and metal detectors cannot be used.

  To deposit a tin vapor deposition layer on an ink layer, a tin vapor deposition film is separately formed by forming a tin vapor deposition layer on the vapor deposition film, even if vapor deposition is performed directly on the ink layer (via an anchor coat layer). The vapor deposition layer and the ink layer may be laminated by dry laminating tote. The direct laminating method does not require a vapor deposition film and can reduce the cost accordingly, and has the advantage of being suitable for vapor deposition on a large lot of printing film from opening and closing of the vacuum vapor deposition kettle, the indirect lamination. The method has an advantage that if a vapor deposition film is subjected to tin vapor deposition, a printing / tin vapor deposition layer laminated film can be easily produced by laminating even a small lot printing film by dry lamination.

  As the film for vapor deposition, a CPP film or an unstretched PS film can be used. These films can be formed into laminates for molding by heat bonding during the extrusion of the same type of resin base sheet. Also, when the base sheet is a foam base sheet, preheating of the sheet and printing / tin A laminate for molding can be easily produced by a hot roll from the vapor deposition layer film side.

  As the adhesive used in the dry laminate, a two-component curable adhesive comprising a polyester-based main component and an isocyanate curing agent, and a two-component curable adhesive comprising a polyether-based main component and an isocyanate curing agent. Both can be used.

  Base film layer / ink layer / anchor coat layer / tin vapor deposition layer or / base film layer / ink layer / dry laminate adhesive layer / tin vapor deposition layer / anchor coat layer / deposition film A printing / tin vapor deposition laminated film and a base material sheet are laminated to form a molding laminate.

  As the base sheet layer, a PP sheet, a talc-containing PP sheet, a foamed PP sheet, a talc-containing PET sheet, a foamed PS sheet, or a heat-resistant foamed PS sheet can be used. The substrate sheet layer can ensure the rigidity of the food container and also has heat resistance, so that heating with a microwave oven is possible. In the case of a foamed PP sheet or a heat-resistant foamed PS sheet, the food container can be directly held by hand because it does not reach the outer surface of the food container even when the stored food is at a high temperature.

  In the case of a PP sheet, a talc-containing PP sheet, and a talc-containing PET sheet for laminating a printing / tin vapor deposition laminated film and a base sheet, a method of dry lamination or a method of heat bonding by heat during extrusion (described later) In the case of a foamed PP sheet, a foamed PS sheet, and a heat-resistant foamed PS sheet, there is a method of heat bonding with a hot roll (see FIG. 5 described later).

  Using a molding laminate, it is molded into various trays, bottles, cups, etc. by vacuum or vacuum / pressure forming machines to produce food containers.

  The following manufacturing methods can be adopted as the manufacturing method of the food container as described above.

  An ink layer is printed on the base film by gravure printing, an anchor coat layer for vapor deposition is coated on the ink layer, a tin vapor deposition layer is applied to the anchor coat layer, and the base film layer / ink layer / anchor coat layer / A printed / tin-deposited laminated film comprising a tin-deposited layer is prepared, and the tin-deposited layer and the substrate sheet of the printed / tin-deposited laminated film are laminated by dry lamination to form a substrate film layer / ink layer / anchor coat layer / A laminate for molding composed of a tin vapor deposition layer / dry laminate adhesive layer / base sheet layer is prepared, and after heating the molding laminate to a predetermined temperature, it is molded into a container by a vacuum or vacuum / pressure forming machine. .

  By the production method as described above, an ink layer is printed on a base film by gravure printing, an anchor coat layer for vapor deposition is coated on the ink layer, and a tin vapor deposition layer is applied to the anchor coat layer. A tin vapor deposition layer can be easily and closely laminated on the back side. Moreover, since the tin vapor-deposited layer of the printing / tin vapor-deposited laminated film and the base sheet are laminated by dry lamination, a molding laminate can be easily produced. As a result, the above-described food container can be easily manufactured.

  The ink film is printed on the base film by gravure printing, and after the deposition film is coated with the anchor coat layer for deposition, a tin deposition layer is applied to the anchor coat layer, and the ink layer and the tin deposition layer are dried. A printing / tin vapor deposition laminated film comprising a base film layer / ink layer / dry laminate adhesive layer / tin vapor deposition layer / anchor coat layer / vapor deposition film layer is prepared by laminating, and the printing / tin vapor deposition multilayer film is produced. The film layer for vapor deposition is superposed on the substrate sheet immediately after extrusion to form the substrate sheet, and is heat-laminated by heat during extrusion to form a substrate film layer / ink layer / dry laminate adhesive layer / A molding laminate comprising a tin vapor deposition layer / anchor coat layer / vapor deposition film layer / base sheet layer was prepared, and the molding laminate was heated to a predetermined temperature. It is formed into containers by vacuum or vacuum-pressure forming machine.

  According to the manufacturing method as described above, an ink layer is printed on the base film by gravure printing, and after depositing an anchor coat layer for vapor deposition on the vapor deposition film, a tin vapor deposition layer is applied to the anchor coat layer, and the ink Since the layer and the tin vapor deposition layer are laminated by dry lamination, the tin vapor deposition layer can be easily and closely laminated on the back side of the ink layer. In addition, the film layer for vapor deposition of the printing / tin vapor deposition laminated film is superposed on the base sheet immediately after being extruded to form the base sheet, and is thermally bonded by heat at the time of extrusion. It can be easily manufactured. As a result, the above-described food container can be easily manufactured.

  The ink film is printed on the base film by gravure printing, and after the deposition film is coated with the anchor coat layer for deposition, a tin deposition layer is applied to the anchor coat layer, and the ink layer and the tin deposition layer are dried. Laminate by lamination to produce printing / tin vapor deposition laminated film consisting of base film layer / ink layer / dry laminate adhesive layer / tin vapor deposition layer / anchor coat layer / deposition film layer, The film for vapor deposition of the printed / tin vapor-deposited laminated film is superposed on the preheated foamed substrate sheet, and the substrate film is heated and pasted from the printed / tin vapor-deposited laminated film side with a hot roll. Laminate for molding comprising layer / ink layer / dry laminate adhesive layer / tin deposited layer / anchor coat layer / deposited film layer / foamed substrate sheet layer Produced, after heating the molded laminate for a predetermined temperature, formed into containers by vacuum or vacuum-pressure forming machine.

  According to the manufacturing method as described above, an ink layer is printed on the base film by gravure printing, and after depositing an anchor coat layer for vapor deposition on the vapor deposition film, a tin vapor deposition layer is applied to the anchor coat layer, and the ink Since the layer and the tin vapor deposition layer are laminated by dry lamination, the tin vapor deposition layer can be easily and closely laminated on the back side of the ink layer. In addition, the film layer for vapor deposition of the printing / tin vapor deposition laminated film is superposed on the preheated foam base material sheet, and it is heat bonded from the printing / tin vapor deposition laminated film side with a hot roll, so that the molding laminated material is It can be easily manufactured. As a result, the above-described food container can be easily manufactured.

[Preparation of base film (unstretched A-PET film)]
Hitachi Zosen's co-rotating twin-screw extruder “HMT100” (L / D = 38, discharge rate: 650 kg / hr, 2 vent holes), China, Huajun Packaging Materials Co., Ltd. PET resin “CR8816” Viscosity 0.815 dl / g, water content 400 ppm) was dried at 140 ° C. for 4 hours or more and water content was reduced to 50 ppm or less, and the extrusion temperature was 280 ° C. on a biaxially stretched PET film (12 μm) coated with silicon on one side. Extrusion lamination was performed on the silicon surface to prepare a laminate of unstretched A-PET film layer (20 μm) / silicon layer / biaxially stretched film layer (12 μm). Next, it wound up, peeling an unstretched A-PET film layer from this laminated body, and produced the winding roll which consists only of unstretched A-PET film (20 micrometers).

[Preparation of printed / tin-deposited laminated film (multicolor printing, tin deposition layer)]
The produced unstretched A-PET film (20 μm) is subjected to corona discharge treatment to a wetness index of 42 dyne / cm or more, and then used with a five-color printer “FM-5S” manufactured by Fuji Machine Co., Ltd. Using an oil-based gravure ink “Ramiol Mark IIIR Grade” (urethane-based vehicle, 3% addition of lamiol curing agent), multi-color printing such as a pattern of meat sauce gratin, product description, precautions, etc. was performed to form an ink layer. This ink layer surface is coated with an anchor coat “VM Anchor P331, 2 liquid (LBNYB additive A 15%)” manufactured by Toyo Ink Mfg. Co., Ltd., and a metal tin vapor deposition layer using metal tin as a vapor deposition source by a vacuum vapor deposition machine. Was vapor-deposited under the condition that the light transmittance was 10%, and a printed / tin-deposited laminated film comprising unstretched A-PET film layer / ink layer / anchor coat layer / tin vapor deposition layer was produced.

[Preparation of substrate sheet]
China, Huajun Packaging Materials Co., Ltd. PET resin “CR8816” (inherent viscosity 0.815 dl / g, water content 400 ppm) 87 parts by weight, Matsumura Chemical Co., Ltd. Talc MB (prototype: PETG 40 wt% + talc 60 wt%) 8 parts by weight, 1 part by weight of chain extender MB manufactured by Meikai Chemical Co., Ltd. (prototype: 70% by weight of PETG + 30% by weight of ADR4368S manufactured by BASF Japan), and white pigment MB “L” manufactured by Dainippon Ink Co., Ltd. -9583 "(50% by weight of PET + 50% by weight of white pigment) was weighed using a gravimetric quantitative feeder and mixed uniformly with a mixer.

  The mixed PET resin material (for the main layer) thus mixed is put into a main extruder (“TEX1052” manufactured by Nippon Steel Works Co., Ltd .: L / D = 31.5, biaxial, 2 vent holes) and an extrusion temperature of 280 Extruded while suctioning and degassing under high vacuum of -101 KPa from a vent hole at ℃, PET resin “CR8816” (Inherent viscosity 0.815 dl / g, moisture content 400 ppm) made in Huajun Packaging Materials Co., Ltd. (for inner layer) ) To a sub-extruder (“TEX65α” manufactured by Nippon Steel Works Co., Ltd .: L / D = 31.5, 2 shafts, 2 vent holes), extrusion temperature of 280 ° C., high vacuum of −101 KPa from both vent holes Extrusion was performed while sucking and degassing below, and a base sheet composed of a main layer (400 μm) / inner layer (30 μm) was formed by coextrusion from a T die.

  The base sheet as described above can be produced by a sheet manufacturing apparatus as shown in FIG. 2, in which 11 is a weight type quantitative feeder, 12 is a main extruder, 13 is a vent hole, and 14 is a vent hole. A sub-extruder, 15 is a vent hole, 16 is a T die, and a is a base sheet composed of a main layer and an inner layer. In such a manufacturing apparatus, PET resin, talc MB, chain extender MB, and white pigment MB are charged into the gravimetric feeder 11 and mixed uniformly. Next, the mixed PET resin material is put into the main extruder 12 and extruded while being sucked and degassed from the vent hole 13, and the PET resin is put into the sub-extruder 14 and sucked and degassed from the vent hole 15. While extruding, lamination is performed by coextrusion from the T die 16 to form the base sheet a.

[Production of laminated material for molding (printing / bonding of tin-deposited laminated film and substrate sheet)]
The roll of the printing / tin vapor deposition laminated film is set in a dry laminator “LX-3” manufactured by Nakajima Seiki Engineering Co., Ltd., and a urethane adhesive (main agent: TM) manufactured by Toyo Morton Co., Ltd. is formed on the surface of the tin vapor deposition layer. -569, curing agent: CAT-RT37, solvent: ethyl acetate) was applied with a gravure roll having a screen line number of 95 lines at a processing speed of 28 m / min, and heat-solidifying temperatures of 40 ° C., 65 ° C., and 55 ° C. After drying, the base sheet (main layer (400 μm) / inner layer (30 μm)) and the main layer surface are bonded together at a linear pressure of nip pressure of 18 kg-cm, and unstretched A-PET film layer (20 μm) / A molding laminate comprising an ink layer / tin deposition layer / dry laminate adhesive layer / main layer (400 μm) / inner layer (30 μm) was produced.

[Molding of food containers (gratin containers)]
Using a vacuum and pressure forming machine “FVS-5000P” manufactured by Wakisaka Engineering Co., Ltd., the molding die was made in a similar shape so that the gap between the female die and the male die was 1.0 mm. A 0.7 mm vacuum / compressed air port was formed in both the mold and the male mold, and suction and compressed air blowing were made possible by switching between vacuum and compressed air. The mold shape was a female mold with an upper diameter of 11 cmφ, a lower diameter of 9 cmφ, a depth of 25 cm, and a rounded bottom corner.

  The molding laminate was heated and softened with a heater to a surface temperature of 130 ° C., and then the female mold was set to 170 ° C. and the male mold was set to 70 ° C. In this state, the vacuum / pressure port of the female mold is evacuated, the vacuum / pressure port of the male mold is pressurized, and 0.5 MPa of compressed air is blown into the female mold for 5.0 seconds. It was made to adhere and formed into a container. Next, after the vacuum / pressure port of the female mold is pressurized and 0.5 MPa of compressed air is blown in, the vacuum / pressure port of the male mold is evacuated and the container is brought into close contact with the male mold for 5.0 seconds and cooled. The container was removed. The molded container was well-released from the mold, was completely free from wrinkles and deformation, and completely reproduced the mold shape.

[Appearance of food container]
The appearance was not fading or discoloration of the printing ink, and the appearance of the printing was very rich in cosmetics due to the reflected light from the tin vapor deposition layer arranged on the back side of the ink layer. Further, the appearance was extremely glossy, and there was no trouble such as matting.

[Crystallinity of main layer and talc content]
A part of the bottom of the molded container is cut off and the part corresponding to the inner layer (30 μm) is removed by scraping with an industrial razor blade. The part corresponding to the main layer (400 μm) is then removed with the same industrial razor. Then, 10.0 mg of the sample was scraped off and used as a sample, each calorific value was obtained with a differential scanning calorimeter (Seiko Electronics “DSC220”), and the crystallinity was calculated based on the following formula. The measurement conditions were a measurement sample (10.0 mg) and nitrogen of 50 ml / min. Flow rate is 10 ° C / min. The temperature was raised to 20 to 300 ° C. and measured.

The crystallinity was 26.5%.
The content of talc was calculated based on the following formula.

  Based on the following formula, the solid content that is solid and exhibits heat resistance even at temperatures inside and outside 200 ° C. at which the amorphous part of the PET resin softens and melts was calculated.

  As a result, the solid content is 31.3%, and if the solid content of PET crystallinity + talc content is 25% or more, it can withstand the cooking of frozen gratin at 250 ° C. for 15 minutes (patent) No. 5767259.), It was confirmed that the molded container of this example had sufficient heat resistance.

[Heat resistance of food containers]
280 g of cooked meat sauce gratin which was cooked on the market was transferred to the food container and heated in a steam oven range “ER-MD7” manufactured by Toshiba Lifestyle Co., Ltd. at 130 ° C. for 45 minutes. When the contents were taken out and washed and the appearance was observed, the container was not deformed by heating, and the printing appearance rich in cosmetics by tin deposition immediately after molding was maintained without being discolored or discolored by the printing ink.

[Applicability to metal detectors]
The food container was allowed to pass through a conveyor type metal detector “NA2-T300” manufactured by Nikka Denki Co., Ltd., but no metal was detected. Next, when the Fe sphere for confirmation of normal operation of the detector: 1.2 mmφ and the SUS sphere: 2.0 mmφ were put in an empty food container and passed through, respectively, both the Fe sphere and the SUS sphere detected “metal present” and were normal. It was confirmed that it was working. This confirmed that a metal detector could be used. This is because electromagnetic induction does not occur because the tin vapor deposition layer has an island-like structure and is electrically insulating.

[Adequacy of microwave heating]
The food container was left in an empty state for 600 W for 5 minutes in a steam oven range “ER-MD7” manufactured by Toshiba Lifestyle Co., Ltd., and the state was observed. There wasn't. Next, 280 ml of water at 25 ° C. was put into a food container, and a microwave oven was applied for 600 W−2 minutes. The state was observed, but no change such as sparking occurred. The water temperature was increased to 65 ° C. This is because the tin deposition layer has an island-like structure and is electrically insulative, so that no spark or the like occurs, and the contents pass through the island-like interval between 100 mm and 5000 mm narrower than the inside and outside of the microwave wavelength of 10 cm. This is because the water of the product was heated.

[Preparation of printing film]
A biaxially stretched PP film “LOP” (18 μm) by a tubular method manufactured by Kojin Film & Chemicals Co., Ltd. is subjected to corona discharge treatment to a wetness index of 42 dyne / cm or more, and then 5-color printing manufactured by Fuji Machine Co., Ltd. By using the machine “FM-5S” type, Sakata Inx Co., Ltd. oil-based gravure ink “Lamiol Mark IIIR grade (urethane-based vehicle, 3% of Lamiol curing agent added)” is used, and the entire surface is golden and at intervals of 0.5 cm Printing with black checkered stripes was performed to produce a printing film composed of a biaxially stretched PP film layer / printing layer.

[Production of tin-deposited film]
On the other hand, CPP film “KL12” (25 μm) manufactured by Sun Tox Co., Ltd. was coated with an anchor coat “VM Anchor P331, 2 liquid” (LBNYB additive A15%) manufactured by Toyo Ink Manufacturing Co., Ltd., A metal tin vapor deposition layer was vapor-deposited under the condition that the light transmittance was 10% using metal tin as a vapor deposition source by a vacuum vapor deposition machine to produce a tin vapor deposition film consisting of a CPP film / anchor coat layer / tin vapor deposition layer.

[Preparation of printed and tin-deposited laminated film (lamination of printed film and tin-deposited film)]
The roll of the tin vapor deposition film was set in a dry laminating machine LX-3 manufactured by Nakajima Seiki Engineering Co., Ltd., and a urethane adhesive (main agent: TM-569, curing agent: Toyo Morton Co., Ltd.) was formed on the surface of the tin vapor deposition layer. CAT-RT37, solvent: ethyl acetate) was applied at a processing speed of 50 m / min with a gravure roll having a screen line number of 95 and dried in three zones with hot air temperatures of 40 ° C., 65 ° C. and 55 ° C., and then the printing film. Are bonded together with a linear pressure of nip pressure of 18 kg-cm together with the printed layer surface, and a biaxially stretched PP film layer (18 μm) / ink layer / dry laminate adhesive layer / tin vapor deposition layer / anchor coat layer / CPP film layer ( A printed and tin-deposited laminated film consisting of 25 μm) was produced.

[Production of molding laminates]
Sun Allomer Co., Ltd. PP resin “VB370A” (MFR: 1.5, block PP) was applied to Hitachi Zosen Co., Ltd., co-rotating twin screw extruder “HMT100” (L / D = 38, discharge amount: 650 kg / hr) and extruded from the T die, and the CPP film layer of the printing / tin vapor deposition laminated film is extruded so as to be in contact with the PP resin and thermally bonded to the PP resin film, and the biaxially stretched PP film layer (18 μm) ) / Ink layer / dry laminate adhesive layer / tin vapor deposition layer / CPP film layer (25 μm) / PP resin sheet (400 μm).

  3 can be produced by a laminating apparatus as shown in FIG. 3. In this figure, 21 is a T die, 22 is a nip roll, 23 is a cooling roll, b is a molten PP resin film. , C is a printing / tin vapor deposition laminated film, and d is a molding laminate. In such a laminating apparatus, the PP resin extruded from an extruder (not shown) is extruded from the T die 21 as a molten PP resin film b, and the printing / tin-deposited laminated film has a CPP film layer as a molten PP resin film. It feeds out so that it may contact b, and heat-bonds with the nip roll 22 and the cooling roll 23, and produces the laminated material d for shaping | molding.

[Formation of food container (tray)]
After the molding laminate was softened by heating to a surface temperature of 90 to 120 ° C. with a heater, the long diameter (25 cm) as shown in FIG. 4 was obtained with an FKC type vacuum / pressure forming machine manufactured by Asano Laboratory. ) × minor diameter (17 cm) × depth (3 cm), female aluminum mold divided into large, medium and small by flange width (1 cm), vacuum / pneumatic molding with 0.5 MPa pressure applied, lunch box A tray was prepared. The mold was a cooling mold. In addition, it arrange | positioned so that the printing layer of the molding laminated material might become an inner surface side. The tray was easy to release from the mold, and wrinkles and deformation were completely reproduced.

[Appearance of food container]
There was no fading or discoloration of the printing ink, and the gold color, which was said to be difficult to develop in normal printing, was also brilliant. This is considered that the reflected light from the tin vapor deposition layer arrange | positioned at the back side of an ink layer also became the wonderful expression. Further, the appearance was extremely glossy, and there was no trouble such as matting.

[Applicability to metal detectors]
In the same manner as in Example 1, a conveyor type metal detector “NA2-T300” manufactured by Nikka Densaku Co., Ltd. was used, and the tray was emptied, but no metal was detected. Further, the normal operation of the detector was confirmed in the same manner as in Example 1, but the Fe sphere: 1.2 mmφ and the SUS sphere: 2.0 mmφ were also “normal” with normal operation.

[Microwave suitability and heat resistance]
As in Example 1, an empty tray was placed in a steam oven range “ER-MD7” manufactured by Toshiba Lifestyle Co., Ltd. and a microwave oven was applied for 600 W for 5 minutes, but no change such as sparking occurred.

  Moreover, when the tonkatsu was put into the division part classified into "large" and the microwave oven was applied for 600W-3 minutes, the temperature of the tonkatsu was 120 degreeC. The tonkatsu was taken out and washed with a detergent, and the portion where the tonkatsu was present was observed. However, there was no wrinkle or the like, and there was no change like the other portions. This is because the inner surface of the tray is an OPP film and has no change because it has oil resistance and heat resistance.

[Preparation of printing film]
Asahi Kasei Co., Ltd. biaxially stretched PS film “GMCO” (30 μm) is subjected to corona discharge treatment to a wetting index of 42 dyne / cm or higher, and then Fuji Machine Co., Ltd. 5-color printing machine “FM-5S” type is used. Using Sakata Inx Co., Ltd. oil-based gravure ink “Lamiol Mark IIIR Grade (urethane-based vehicle, 3% addition of Lamiol curing agent)”, Susuki ears, distant mountains, and the full moon climbing from the mountains A landscape image imitating "Moon" (no printing in the full moon) was printed, and a printing film composed of a biaxially stretched PS film layer / ink layer was produced.

[Production of tin-deposited film]
An unstretched PS film “SPH” (20 μm) manufactured by Oishi Sangyo Co., Ltd. is coated with an anchor coat “VM Anchor P331, 2 liquid (LBNYB additive A 15%)” manufactured by Toyo Ink Manufacturing Co., Ltd. A metal-tin vapor deposition layer was vapor-deposited with a vapor deposition machine under the condition that the light transmittance was 10% by using metal tin as a vapor deposition source, and a tin vapor-deposited film consisting of unstretched PS film / anchor coat layer / tin vapor deposition layer was produced.

[Preparation of printed and tin-deposited laminated film (lamination of printed film and tin-deposited film)]
A roll of tin vapor deposition film is set in a dry laminating machine “LX-3” manufactured by Nakajima Seiki Engineering Co., Ltd., and a urethane adhesive (main agent: TM-569, cured) manufactured by Toyo Morton Co., Ltd. on the surface of the tin vapor deposition layer. Agent: CAT-RT37, solvent: ethyl acetate) was applied with a gravure roll having a screen line number of 95 lines at a processing speed of 50 m / min, and after drying in three zones of hot air temperatures of 40 ° C., 65 ° C., and 55 ° C., Bonded together with the printing layer surface of the printing film at a linear pressure of nip pressure 18 kg-cm, biaxially stretched PS film layer (30 μm) / ink layer / dry laminate adhesive layer / tin vapor deposition layer / PS film layer (20 μm) A printed and tin-deposited laminated film was prepared.

[Production of molding laminates]
A heat-resistant foamed PS sheet (thickness: 2.0 mm) foamed seven times with butane gas is preheated with a heater, and a PS film layer of a printed / tin-deposited laminated film is laminated on the preheated heat-resistant foamed PS sheet with a heating roll. Laminated by heat bonding and consists of biaxially stretched PS film layer (30 μm) / ink layer / dry laminate adhesive layer / tin deposited layer / PS film layer (20 μm) / heat-resistant foamed PS sheet (thickness: 2.0 mm) A molding laminate was produced.

  The above-mentioned laminated material for molding can be produced by a laminating apparatus as shown in FIG. 5. In this figure, 31 is a heater, 32 is a heating roll, 33 is a nip roll, e is a heat-resistant foamed PS sheet, f is a printing / tin vapor deposition laminated film, and g is a molding laminate. In such a laminating apparatus, the heat-resistant foamed PS sheet e is fed out and heated by the heater 31. On the other hand, the printing / tin vapor deposition film f is also fed out, and the PS film layer surface is superposed on the heat-resistant foamed PS sheet e in the superheating roll 32 and the nip roll 33, and heat-bonded, and a laminated material for molding g is produced.

Processing speed: 20m / min
Preheating of heat-resistant foamed PS sheet: 90 ° C (surface temperature)
Heating roll temperature: 120 ° C
Heat roll contact distance of laminated film: 50 cm (1.5 second contact)
Nip pressure: 6Kg-cm

[Formation of food container (tray)]
After the molding laminate was softened by heating to a surface temperature of 90 to 120 ° C. with a heater, the diameter (30 cmφ) × depth (2 cm) was measured with an FKC vacuum / pressure forming machine manufactured by Asano Laboratories. ), Using a tray-like aluminum mold with a flange width (1.5 cm), vacuum and pressure molding was performed while applying 0.5 MPa of compressed air to produce a delivery delivery tray for sushi, pizza and the like. The molded product was well released from the mold, and the mold shape was completely reproduced without wrinkles or deformation.

[Appearance of food container]
Appearance was not fading or discoloration of the ink, and the full moon without printing ink in particular gave a stunning cosmetic effect with the silver reflected light from the tin deposited layer. Further, the appearance was extremely glossy, and there was no trouble such as matting.

[Applicability to metal detectors]
In the same manner as in Example 1, a conveyor type metal detector “NA2-T300” manufactured by Nikka Densaku Co., Ltd. was used, and the tray was emptied, but no metal was detected. Further, the normal operation of the detector was confirmed in the same manner as in Example 1, but the Fe sphere: 1.2 mmφ and the SUS sphere: 2.0 mmφ were also “normal” with normal operation.

11: Weight type quantitative feeder 12: Main extruder 13: Vent hole 14: Sub extruder 15: Vent hole 16: T die 21: T die 22: Nip roll 23: Cooling roll 31: Heater 32: Heating roll 33: Nip roll b : Melted PP resin c: Printing / tin vapor deposition laminated film d: Molding laminate a: Base sheet e: Heat-resistant foamed PS sheet f: Printing / tin vapor deposition laminated film g: Molding laminate

Claims (8)

It has a base film layer / ink layer / tin deposition layer / base sheet layer, and the base film layer is an A-PET film, a biaxially stretched PP film or a biaxially stretched PS film, and the tin deposited layer Are deposited on a discontinuous island structure, the island size of the island structure is 200 mm to 10,000 mm, the distance between the islands is 100 mm to 5,000 mm, and the light transmittance is 1% to 15%. A food container characterized by%. The food container according to claim 1, wherein the tin vapor-deposited layer is vapor-deposited on the ink layer. The food container according to claim 1, wherein the tin vapor deposition layer is vapor deposited on a vapor deposition film, and the tin vapor deposition layer and the ink layer are bonded together by dry lamination. 4. The food container according to claim 3, wherein the vapor deposition film is a CPP film or an unstretched PS film. The base material sheet layer is a PP sheet, a talc-containing PP sheet, a foamed PP sheet, a talc-containing PET sheet, a foamed PS sheet, or a heat-resistant foamed PS sheet. Food container. An ink layer is printed on the base film by gravure printing, an anchor coat layer for vapor deposition is coated on the ink layer, a tin vapor deposition layer is applied to the anchor coat layer, and the base film layer / ink layer / anchor coat layer / A printed / tin-deposited laminated film comprising a tin-deposited layer is prepared, and the tin-deposited layer and the substrate sheet of the printed / tin-deposited laminated film are laminated by dry lamination to form a substrate film layer / ink layer / anchor coat layer / A laminate for molding composed of a tin vapor deposition layer / dry laminate adhesive layer / base sheet layer is prepared, and after heating the molding laminate to a predetermined temperature, it is molded into a container by a vacuum or vacuum / pressure forming machine. The method for producing a food container according to claim 1 or 2. The ink film is printed on the base film by gravure printing, and after the deposition film is coated with the anchor coat layer for deposition, a tin deposition layer is applied to the anchor coat layer, and the ink layer and the tin deposition layer are dried. A printing / tin vapor deposition laminated film comprising a base film layer / ink layer / dry laminate adhesive layer / tin vapor deposition layer / anchor coat layer / vapor deposition film layer is prepared by laminating, and the printing / tin vapor deposition multilayer film is produced. The film layer for vapor deposition is superposed on the substrate sheet immediately after extrusion to form the substrate sheet, and is heat-laminated by heat during extrusion to form a substrate film layer / ink layer / dry laminate adhesive layer / A molding laminate comprising a tin vapor deposition layer / anchor coat layer / vapor deposition film layer / base sheet layer was prepared, and the molding laminate was heated to a predetermined temperature. The method of the food container according to claim 1, 3, 4 or 5, wherein the molding to the container by vacuum or vacuum-pressure forming machine. The ink film is printed on the base film by gravure printing, and after the deposition film is coated with the anchor coat layer for deposition, a tin deposition layer is applied to the anchor coat layer, and the ink layer and the tin deposition layer are dried. Laminate by lamination to produce printing / tin vapor deposition laminated film consisting of base film layer / ink layer / dry laminate adhesive layer / tin vapor deposition layer / anchor coat layer / deposition film layer, The film for vapor deposition of the printed / tin vapor-deposited laminated film is superposed on the preheated foamed substrate sheet, and the substrate film is heated and pasted from the printed / tin vapor-deposited laminated film side with a hot roll. Laminate for molding comprising layer / ink layer / dry laminate adhesive layer / tin deposited layer / anchor coat layer / deposited film layer / foamed substrate sheet layer 6. The method for producing a food container according to claim 1, wherein the molding laminate is heated to a predetermined temperature and then molded into a container by a vacuum or vacuum / pressure forming machine. .

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