Pet container and manufacturing method of the same

Abstract

To provide a container having a good visibility even when directly printed.SOLUTION: A PET container includes a transparent container body molded from polyethylene terephthalate (PET) capable of holding a content, an opaque region provided on a part of an outer surface or an inner surface of the container body, and a printed layer including a colorant provided on at least a part of the opaque region. A manufacturing method of the PET container includes a molding step of molding the transparent container body capable of holding the content using polyethylene terephthalate (PET), an opacifying step of at least partially opacifying the outer surface or the inner surface of the container body, and a printing step of forming a print layer on an opacified part of the container body by an inkjet method.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a PET container and a method for producing the same. [Background technology]

[0002] Containers with a printed layer on the surface of the container body are known (Patent Document 1). However, printing on transparent containers is poorly visible, making it difficult to recognize printed characters, codes, etc. Printing characters, etc. on a label on the outside of the container improves visibility, but the label needs to be peeled off when recycling, etc., and there are cases where the labels need to be separated. [Patent Document 1] JP 2018-52607 A Summary of the Invention

[0003] In a first aspect of the present invention, a PET container is provided, which comprises a transparent container body molded from polyethylene terephthalate (PET) and capable of holding contents, an opaque region provided on a portion of the outer or inner surface of the container body, and a printed layer containing a colorant provided on at least a portion of the opaque region.

[0004] In addition, in a second aspect, a method for manufacturing a PET container is provided, comprising: a molding step of using polyethylene terephthalate (PET) to mold a transparent container body capable of holding contents; an opacifying step of at least partially opacifying the outer or inner surface of the container body; and a printing step of forming a printed layer on the opacified portion of the container body by an inkjet method.

[0005] The above summary of the invention does not list all of the necessary features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0006] [Figure 1] 1 shows an example of the appearance of a container 100 in this embodiment. [Diagram 2]1 shows an example of a layer structure of the container 100 in this embodiment. [Diagram 3] 2 shows another example of the layer structure of the container 100 in this embodiment. [Figure 4] 2 shows another example of the layer structure of the container 100 in this embodiment. [Diagram 5] 2 shows another example of the appearance of the container 100 in this embodiment. [Figure 6] 2 shows another example of the appearance of the container 100 in this embodiment. [Figure 7] 2 shows another example of the appearance of the container 100 in this embodiment. [Figure 8] An example of a flow of a method for manufacturing the container 100 of this embodiment will be shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0008] 1 shows an example of a container 100 in this embodiment. The container 100 has a transparent appearance and is at least partially printed. The container 100 has a container body 10, an opaque region 20, a printing layer 30, and a transparent region 35.

[0009] The container body 10 is a structure capable of holding contents. The container body 10 is formed from a recyclable transparent material such as resin or glass. For example, the container body 10 is formed from polyethylene terephthalate (PET), in which case the container 100 becomes a PET container, and is called a PET bottle or the like. The contents held in the container body 10 may be beverages, foods, medicines, industrial products, or the like. The container body 10 will be described in detail later.

[0010] The opaque region 20 is an opaque region provided on a part of the outer surface or inner surface of the container body 10, for example, a part of the outer surface or inner surface of the container body 10 that is whitened. The opaque region 20 may be provided on a part of the container 100 other than the mouth part (i.e., the part to which a lid such as a cap is attached). For example, the opaque region 20 may be provided on a part or the entire body part, bottom part, and / or shoulder part of the container 100.

[0011] The opaque region 20 may be provided so as to surround the entire region where the printed layer 30 is provided as shown in the figure. The opaque region 20 may not be provided in any region other than the region where the printed layer 30 is provided, or may only be provided in a part of the region, so as not to impair the visibility of the contents of the container 100 or the aesthetic appearance of the container 100. For example, the opaque region 20 may be provided in 1 to 95%, preferably 3 to 60%, and more preferably 5 to 30% of the outer surface area of ​​the container 100 excluding the palate portion.

[0012] The printed layer 30 is a layer containing a colorant and provided in at least a part of the opaque region 20. The printed layer 30 provides the container 100 with letters and pictures.

[0013] The transparent region 35 is a transparent region of the container body 10. The transparent region 35 may be a region other than the opaque region 20 of the container body 10. In the transparent region 35, the contents may be at least partially observable from the outside, but it does not need to be completely transparent and may be semi-transparent. In addition, the transparent region 35 may be a region that is colored with a colorant or the like to the extent that transparency is maintained.

[0014] As shown in FIG. 1, the printing layer 30 of the container 100 is formed on the opaque region 20. Therefore, the printed content of the printing layer 30 is easier to see than when the printing layer 30 is provided only in the transparent region 35. For example, if the content is a dark-colored beverage and the printing layer 30 includes black characters or codes, the absence of the opaque region 20 weakens the contrast between the printing layer 30 and the content, significantly worsening visibility. Even if the content is a transparent beverage such as water, a similar visibility problem can occur depending on the background conditions. On the other hand, the presence of the opaque region 20 ensures the contrast between the printing layer 30 and the content, improving visibility.

[0015] Fig. 2 shows an example of the layer structure of the container 100 in this embodiment. In Fig. 2, the upper side is the outer surface of the container 100 (i.e., the surface in contact with the outside air), and the lower side is the inner surface (i.e., the surface in contact with the contents).

[0016] A transparent material, such as glass or resin, can be used as the material of the container body 10. When the opaque region 20 is formed by whitening, the material is preferably a crystallizable resin. As the material, for example, one or a combination of two or more selected from polyester resin, polyolefin resin, polystyrene resin, polyamide resin, acrylic resin, polyvinyl chloride resin, polyacrylonitrile resin, polyvinyl alcohol resin, and biodegradable resin may be used.

[0017] As the polyester resin, thermoplastic polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate are preferably used. As the polyolefin resin, low density / high density polyethylene, polypropylene, poly1-butene, poly4-methyl-1-pentene, and random / block copolymers of any linear or cyclic olefin may be used. As the polystyrene resin, polystyrene, acrylonitrile-styrene copolymer, ABS, or α-methylstyrene-styrene copolymer may be used. As the polyamide resin, nylon 6, nylon 6-6, nylon 6 / 6-6 copolymer, metaxylylenediadipamide, nylon 6-10, nylon 11, nylon 12, and nylon 13 may be used. As the acrylic resin, acrylic acid esters and methacrylic acid esters may be used. As the polyvinyl chloride resin, polyvinyl chloride, polyvinylidene chloride, and the like may be used.

[0018] The container body 10 may contain various additives, such as a plasticizer, a UV absorber, a flame retardant, an antistatic agent, an antioxidant, a weather resistance agent, a deodorizer, a matting agent, a release agent, an ion exchange agent, a colorant, and other additives.

[0019] At least a part of the container body 10 (e.g., a region including the opaque region 20) or the entire outer surface may be subjected to a surface treatment. For example, the container body 10 may be subjected to a plasma treatment, a corona treatment, an ozone treatment, a primer coating treatment, or the like. This can improve the adhesion between the container body 10 and the printing layer 30. The inner surface of the container body 10 may also be subjected to a surface treatment or another layer may be formed thereon. For example, an oxygen barrier film (e.g., a SiOx film) may be formed on the inner surface of the container body 10. The thickness of the container body 10 is arbitrary, but is preferably in the range of, for example, 0.1 to 1.0 mm.

[0020] In the embodiment of FIG. 2, the opaque region 20 is formed on a part of the outer surface of the container body 10. For example, a part of the outer surface of the container body 10 is treated to be opaque, and the opaque region 20 is formed. The opaque region 20 is not a separate opaque layer laminated on the container body 10, but is a part of the container body 10. Therefore, a separate peeling process or the like is not required when recycling the container 100. Unlike FIG. 2, the opaque region 20 may be formed on a part of the inner surface of the container body 10, may be formed over the entire thickness direction from the inner surface to the outer surface of the container body 10, or the opaque region 20 may be formed on both the outer surface and the inner surface.

[0021] The opaque region 20 blocks at least a portion of visible light passing between the inside and outside of the container 100. For example, the total light transmittance of the opaque region 20 may be 85% or less. Preferably, the total light transmittance of the opaque region 20 may be 45% or less, and more preferably 25% or less. The total light transmittance may be calculated as an average of the transmittance for light with a wavelength of 400 to 700 nm. For example, the total light transmittance may be calculated by the method of JIS K7376-1 or a method conforming thereto.

[0022] The opaque region 20 may be realized by various methods. For example, the opaque region 20 may be a region in which the resin (e.g., PET) of the container body is whitened. As an example, the opaque region 20 may be a region in which the resin is at least partially crystallized by heating or the like.

[0023] In this case, the resin turns white when crystallized, and this is utilized to form the opaque region 20. The opaque region 20 formed by crystallization diffuses at least a portion of the visible light passing between the inside and outside of the container 100.

[0024] The thickness of the opaque region 20 formed by crystallization may be any value, but is preferably in the range of 0.05 to 1 mm, for example. If it is less than 0.05 mm, the opacity may be insufficient, resulting in insufficient visibility, and if it exceeds 1 mm, the degree of crystallization may be so high that the resin becomes brittle and prone to cracking. The haze value of the crystallized opaque region 20 may be 0.5 to 100. If it is less than 0.5, the visibility of the pattern of the printed layer 30 decreases.

[0025] The thermally induced crystallinity of the crystallized opaque region 20 may be 15 to 80%, preferably 45 to 80%, and more preferably 55 to 80%. The thermally induced crystallinity may be calculated using the gradient between the density of the uncrystallized resin and the crystal density of the resin based on the measured resin density. The resin density may be measured at room temperature (e.g., 25°C) by a method conforming to ASTM1505. The crystal density of the resin may be a known value, or may be calculated from unit cell parameters.

[0026] For example, the density (dam) of uncrystallized PET is 1.335 g / cm 3 and the density (dcr) of crystallized PET is 1.455 g / cm 3 It is known that the heat-induced crystallinity value is a major factor in determining the heat resistance of heat-resistant PET. Crystallization does not occur throughout the PET, but rather the presence of regular crystals in various places along the molecular chain, and the ratio of these is called the heat-induced crystallinity. The density of PET resin is dam=1.335g / cm for uncrystallized PET. 3 , dcr=1.455g / cm for crystalline PET 3 The degree of crystallinity X is calculated by measuring the density d of the molded product and using the following formula. 1 / d=X / dcr+(1-X) / dam X=dcr(dam-d) / d(dam-dcr) As an example, the measured resin density (d) of PET is 1.394 g / cm 3 In this case, X is calculated to be 51.32%. The thermally induced crystallinity may be determined by the method described in JP-A-2005-531445.

[0027] In addition, if the container body 10 has an inherent color, such as when the container body 10 contains a colorant, the inherent color will not necessarily become white, but will change to a cloudy state. For example, if the container body 10 contains a red colorant, it is expected that the color will change to a light pink color due to crystallization, and such cases are also referred to as "whitening" here.

[0028] Instead of whitening, the opaque region 20 may be a region in which the resin of the container body is partially foamed. In this case, the container body 10 contains a large number of fine air bubble cells in the opaque region 20, and the opaque region 20 is formed by diffusing light that passes through the air bubble cells. The haze value of the opaque region 20 caused by partial foaming may be 0.5 to 100. If it is less than 0.5, the visibility of the pattern of the printing layer 30 decreases.

[0029] The printed layer 30 is formed adjacent to the upper side of the opaque region 20. When the opaque region 20 is formed on the inner surface of the container body 10, the printed layer 30 is formed in a region of the outer surface of the container body 10 corresponding to the opaque region 20 (a region facing the opaque region 20 across the container body 10). The printed layer 30 may be additionally formed not only in the opaque region 20 but also in the transparent region 35.

[0030] The printed layer 30 expresses characters, identification codes, symbols, pictures, patterns, etc. (hereinafter, collectively referred to as "pictures, etc.") formed by various printing processes. Examples of characters include the product name and product description (e.g., the taste of the contents, raw materials, manufacturer, and expiration date, etc.) related to the container 100, and a description of the container body 10 (the material of the container body 10, whether it can be recycled, and the recycling method, etc.). Examples of identification codes include barcodes and two-dimensional codes, which may, instead of characters, show the product name, product description, and description of the container body 10, as well as links to websites, etc. that display this information.

[0031] The printed layer 30 is a cured product of an ink composition formed by printing. The printed layer 30 may contain a binder resin, a colorant, and other additives.

[0032] The binder resin may include an alkali-soluble resin. For example, the binder resin may be an alkali-soluble thermoplastic resin or an alkali-soluble photocurable resin. By being alkali-soluble, the printed layer 30 can be easily peeled off and dissolved later by an alkaline solution, and the container 100 can be easily recycled. The binder resin may further include a resin other than the alkali-soluble resin.

[0033] The colorant may include a pigment or dye that can be used for printing. The colorant is not particularly limited, but it is desirable to include a color that provides high contrast against a white background, such as black, blue, or brown. The content of the colorant may be 1 to 20% by weight, preferably 3 to 15% by weight, based on the entire printed layer 30. Since the printed layer 30 is provided on the opaque region 20, the visibility is superior compared to a case where the opaque region 20 is not present. Therefore, the content of the colorant can be reduced compared to a case where the opaque region 20 is not present.

[0034] Fig. 3 shows another example of the layer structure of the container 100 in this embodiment. In the embodiment in Fig. 3, the opaque region 20 is a region in which the outer surface of the container body 10 is roughened. Unlike Fig. 3, the opaque region 20 may be a region in which the inner surface of the container body 10 is roughened, or may be a region in which both the inner surface and the outer surface are roughened.

[0035] The arithmetic mean roughness (Ra) of the roughened surface of the opaque region 20 may be 0.05 or more and 20 μm or less. The average length (RSm) of the roughened opaque region 20 may be 50 or more and 1000 μm or less. The haze value of the roughened opaque region 20 may be 0.5 to 100. If it is less than 0.5, the visibility of the pattern of the printed layer 30 decreases.

[0036] Moreover, Ra / RSm is preferably 0.001 or more, and more preferably 0.002 or more. When the value of Ra / RSm satisfies the above range, the haze can be further improved, and the visibility of the printed layer 30 can be improved.

[0037] 4 shows another example of the layer structure of the container 100 in this embodiment. As shown in the figure, the container body 10 may include multiple layers. For example, the container body 10 may have an intermediate layer 14, and PET layers 12 and 16 made of polyethylene terephthalate that sandwich the intermediate layer 14.

[0038] The PET layer 12 and the PET layer 16 may have the same configuration as the container body 10 described in Fig. 2. Instead of the PET layer 12 and the PET layer 16, a layer of a resin other than PET, which is listed as a material for the container body 10, may be provided.

[0039] The intermediate layer 14 imparts various functions and added value to the container 100. For example, the intermediate layer 14 may be a layer having oxygen barrier properties. In this case, the intermediate layer 14 may be a polyamide resin such as nylon (e.g., nylon 6, nylon 6-6, nylon 6 / 6-6 copolymer, metaxylylenediadipamide, nylon 6-10, nylon 11, nylon 12, and nylon 13), or an ethylene-vinyl alcohol copolymer (e.g., ethylene-vinyl acetate copolymer), preferably nylon. By using these materials, the preservation quality of the contents can be improved.

[0040] Also, for example, the intermediate layer 14 may be a layer using recycled materials. For example, the intermediate layer 14 may be a recycled resin such as recycled PET. As an example, the intermediate layer 14 may be mechanically recycled PET or chemically recycled PET. By using recycled materials, the environmental load generated in the manufacture of the container 100 can be reduced.

[0041] When the container 100 is made of multiple layers, the haze value of the opaque region 20 may be 1 to 100. If it is less than 1, the visibility of the pattern or the like of the printed layer 30 decreases.

[0042] The container 100 may further include other layers, such as an adhesive layer or other functional layer between the PET layer 12, the intermediate layer 14, and the PET layer 16.

[0043] 4, the opaque regions 20 are provided in the PET layer 12, but instead of or in addition to this, the opaque regions 20 may be provided in another layer. For example, the opaque regions 20 may be provided in the intermediate layer 14 and / or the PET layer 16.

[0044] FIG. 5 shows another example of the appearance of the container 100 in this embodiment. Unlike FIG. 1, the opaque region 20 may not be provided so as to surround the entire area of ​​the printed layer 30, but may be provided so as to border the outline of the pattern or the like of the printed layer 30. For example, the printed layer 30 includes printed characters, and the opaque region 20 is provided at least in the border portion of the characters included in the pattern or the like. When the pattern or the like includes a code such as a two-dimensional code or a barcode, the opaque region 20 may be provided so as to surround the periphery of the code (i.e., in the interior and periphery of the code). As an example, the opaque region 20 may be provided only in the border portion of the outline of the pattern or the like.

[0045] For example, the opaque area 20 may be provided so as to occupy an area of ​​105 to 400%, preferably 110 to 200%, of the area of ​​the independent characters, codes, symbols, etc. of the print layer 30. As an example, 2 If the letter "W" is printed with an area of ​​200%, or 2 cm 2 Opaque region 20 may be formed inside and around the letter "W" to border the letter "W." However, because the letter "W" is formed on opaque region 20, what can be observed from above the letter is 200%-100%=100% opaque region 20.

[0046] Fig. 6 shows another example of the appearance of the container 100 in this embodiment. The opaque region 20 may have a portion where the opacity changes stepwise. For example, as shown in Fig. 6, the portion of the printed layer 30 closest to the pattern or the like may have the highest opacity (e.g., be most strongly whitened), and the opacity may decrease with increasing distance from the pattern or the like.

[0047] 7 shows another example of the appearance of the container 100 in this embodiment. The container 100 has a recess 40 formed on the outer surface or inner surface of the container body 10, separate from the printed layer 30. The recess 40 may be formed to represent characters, symbols, identification codes, pictures, patterns, etc. The recess 40 may be formed by a mold or the like during or after blow molding of the container 100.

[0048] For example, the container 100 may have recesses representing characters or symbols, the recesses representing information about the material of the container body 10, and the printed layer 30 representing information specific to the product sold using the container 100. As an example, the recesses 40 may be formed on the outer surface of the container body 10 with characters "PET" representing polyethylene terephthalate, and the product name of the contents of the container 100 (e.g., the product name of a specific soft drink) and / or information about the product (e.g., ingredients of the soft drink, etc.) or a two-dimensional code of the URL of a website providing the information may be formed on the opaque region 20 as the printed layer 30. This allows containers 100 with information that does not depend on the contents of the container 100 to be mass-produced using a mold or the like, and different information depending on the contents can be added later on demand by digital printing or the like.

[0049] Next, a description will be given of a manufacturing method of the container 100. The manufacturing method of the container 100 may include at least a molding step, an opacifying step, and a printing step.

[0050] In the molding step, the transparent material is molded to form the transparent container body 10 capable of holding the contents. The molding step may include a preform molding step and a blow molding step.

[0051] In the opacifying step, the outer or inner surface of the container body 10 is at least partially opacified to form the opaque region 20. The opacifying step may be performed after the molding step as a separate step. Alternatively / in addition to this, the opacifying step may be performed during the molding step.

[0052] In the printing step, a printing layer 30 is formed on at least the opaque region 20 of the container body 10 .

[0053] Fig. 8 shows an example of a flow of a method for manufacturing the container 100 of this embodiment. The container 100 of this embodiment can be manufactured by performing the processes of S100 to S500 in Fig. 8. For convenience of explanation, the processes of S100 to S500 will be explained in order, but at least some of these processes may be performed in parallel, or each step may be interchanged without departing from the spirit of the present invention. Also, some steps may be omitted.

[0054] First, in S100, a preform is molded. For example, a transparent material such as a resin that is to be the material of the container body 10 may be melted at high temperature and pressure, injected and filled into a mold, and then cooled and solidified to form a preform having the shape of the mold. The temperature during melting and injection may be in the range of, for example, 200°C to 300°C. The pressure during injection may be appropriately set depending on the shape of the container, and may be in the range of, for example, 10 to 40 MPa. After injection, the preform may be rapidly cooled. This prevents the entire preform from crystallizing and becoming opaque.

[0055] In S100, a single-layer preform may be formed by injecting a single-layer resin, or a multi-layer preform may be formed by co-injecting multiple resins into a mold. Instead of / in addition to co-injection, a multi-layer preform may be formed by co-compression molding, sequential injection, or the like.

[0056] When a multi-layer preform is formed, a container 100 as shown in Fig. 4 is obtained. When forming a multi-layer preform, co-injection may be performed so that a resin having a specific function (for example, a resin having oxygen barrier properties such as nylon or a recycled resin) is positioned between resins serving as base materials (for example, PET).

[0057] The palate of the injection molded preform may be heat-treated to crystallize it. The crystallization of the palate of the preform can impart heat resistance. The heat treatment temperature may be any temperature at which the material crystallizes, and may be, for example, in the range of 140°C to 200°C.

[0058] Next, in S200, the preform is blow molded. For example, biaxial stretch blow molding may be performed. As an example, the preform may be inserted into a mold after heating, stretched in the longitudinal direction of the preform with a stretch rod (i.e., vertical stretching) to elongate the preform in the longitudinal direction, and then stretched by blowing compressed air into the preform so that the radius of the preform is enlarged (i.e., horizontal stretching), thereby forming the container body 10.

[0059] The blow molding may be performed while heating the preform at a temperature equal to or higher than the glass transition point (Tg) and equal to or lower than the crystallization temperature of the material. For example, when the material of the container body 10 is PET, it may be heated to 100 to 130°C. Known methods such as infrared rays, high-frequency induction, and hot air are used as the heating method. After the molding of the container body 10 is completed, the pressurized air may be replaced with cooling air (e.g., air, carbon dioxide, nitrogen gas, or a liquefied form of these, etc.) and sent into the container body 10 to cool the container body 10.

[0060] The recess 40 may be formed during blow molding. For example, the recess 40 described in FIG. 7 may be provided by placing a mold on which a pattern or the like is formed in a convex shape outside the preform and performing blow molding.

[0061] Next, in S300, the opaque region 20 is formed in the container body 10. The opaque region 20 may be formed by at least partially whitening the resin, such as PET, of the container body 10. The whitening may be achieved by at least partially crystallizing the resin, such as PET, of the container body 10.

[0062] For example, the heated portion may be crystallized by heating a part or the whole of the trunk portion, the bottom portion, and / or the shoulder portion of the container body 10. The temperature of the heated portion may be set to a temperature at which the material crystallizes, for example, in the range of 140°C to 200°C.

[0063] Heating may be performed by pressing a heating member such as a heated mold against the portion of the container body 10 that is to become the opaque region 20, irradiating infrared rays, irradiating a laser, or the like. For example, when a rectangular heated heating member is pressed against the barrel of the container body 10 to crystallize it, a certain area of ​​the opaque region 20 is provided as shown in FIG.

[0064] When heating is performed using a laser or the like along the contour of a pattern or the like on the printed layer 30, a bordered opaque region 20 is provided as shown in Fig. 5. By adjusting the amount of heat applied by the laser according to the distance from the contour of the pattern or the like, graduated opaque regions 20 are provided as shown in Fig. 6.

[0065] When the opaque region 20 is formed by crystallization, heating may be performed so that the heat-induced crystallinity of the opaque region 20 is 15 to 80%, preferably 45 to 80%, and more preferably 55 to 80%. The same applies when crystallization is performed in the preform molding stage described below.

[0066] The opaque region 20 is preferably provided on the outer surface of the container body 10, but instead of / in addition to this, it may be formed on the inner surface of the container body 10. For example, the opaque region 20 may be formed on the inner surface by irradiating a laser or infrared light from inside the container body 10 to a portion corresponding to the opaque region 20.

[0067] Instead of whitening by crystallization, the opaque region 20 may be formed by roughening the outer or inner surface of the container body 10. For example, the outer surface of the container body 10 may be roughened by mechanical means (e.g., mechanical polishing, sandblasting, etc.), chemical means (e.g., ozone treatment), or physical means (e.g., laser treatment). When sandblasting is used, the container body 10 may be directly sandblasted, or the surface of a mold may be sandblasted to form a rough surface, and the rough surface of the mold may be transferred to the surface of the preform during blow molding to form the opaque region 20. When sandblasting is used, glass beads, glass powder, alumina particles, etc. may be used as the sandblasting material.

[0068] Next, in S400, a printed layer 30 is formed on the outer surface of the container body 10. The printed layer 30 is provided at least in the opaque region 20 of the container body 10, but may additionally be provided in the transparent region 35. By forming the printed layer 30 on both, the visibility of important information can be improved, and the decorativeness of the container 100 can be enhanced.

[0069] The method for forming the printed layer 30 is not particularly limited, but examples include various printing methods such as inkjet printing, offset printing, gravure printing, and electrophotographic printing, and coating methods such as roll coating. In particular, the inkjet method that allows on-demand printing is preferable. After printing or coating, a step of drying and curing the ink may be performed. Curing may be performed by thermal curing or ultraviolet curing.

[0070] A known ink composition can be used to form the printed layer 30. For example, a material that includes an appropriate solvent, additives, etc., added to the materials described above for the printed layer 30 can be used. In particular, from the viewpoint of reducing environmental impact, it is desirable to use an ink composition that contains an alkali-soluble resin. The content of the colorant in the ink composition is preferably 1 to 20% by weight, more preferably 3 to 15% by weight, based on the solid content weight. As described above, the printed layer 30 has excellent visibility due to the opaque region 20, so the content of the colorant in the ink composition can be reduced compared to a case where the opaque region 20 is not present.

[0071] The printing layer 30 may be a single layer or multiple layers. In addition, another layer may be provided on the printing layer 30 as necessary. For example, a protective layer may be provided on the printing layer 30 to protect the printing layer 30 from physical / chemical damage.

[0072] Next, in S500, the container 100 after the formation of the printed layer is inspected. For example, the outer or inner surface of the container 100 is inspected for dents, holes, scratches, stains, etc. For example, the container 100 is inspected for sufficient opacity of the opaque area 20 formed thereon. In addition, for example, the container 100 is inspected for sufficient clarity of the pattern, etc. formed thereon, and for the absence of printing misalignment, chipping, bleeding, etc. The inspection may be performed using an inspection device or visually by a human.

[0073] In the above example, the formation of the opaque region 20 (S300) is performed after the blow molding (S200), but it may be performed in other ways. For example, the formation of the opaque region 20 may be performed in parallel with the blow molding and / or in parallel with the molding of the preform.

[0074] When the opaque region 20 is formed in parallel with the blow molding, a part of the container body 10 may be heated to the crystallization temperature or higher simultaneously with the blow molding. For example, while blow molding is being performed, a heating member such as a heated metal mold or a metal mold roughened by sandblasting may be pressed against the part of the container body 10 that is to become the opaque region 20, infrared rays may be irradiated, a laser may be irradiated, or the like.

[0075] When forming a multi-layer preform in S100, any one, several, or all of the layers may be foamed. For example, in the case of a three-layer structure as shown in Fig. 4, only the middle layer corresponding to the middle layer 14 of the preform may be foamed. In this case, only the middle layer may contain a foaming agent.

[0076] When the formation of the opaque region 20 is performed in parallel with the molding of the preform, the crystallization (i.e., opacification) may be promoted by slowly cooling only the portion of the mold into which the resin is injected that contacts the region of the preform in which the opaque region will later be formed, rather than rapidly cooling it after injection. Also, the region of the preform in which the opaque region will later be formed may be injected at a higher temperature than other portions.

[0077] Instead of / in addition to the slow cooling method, the resin (e.g., nylon or recycled PET) forming the intermediate layer may be insufficiently kneaded to facilitate the generation of nuclei that serve as the starting points for crystallization in the resin, and promote crystallization (i.e., opacification). For example, the insufficient kneading state may be induced by lowering the temperature during plasticization of the resin forming the intermediate layer, and by reducing the back pressure and rotation speed of the screw. As an example, when the resin of the intermediate layer is nylon or recycled PET, the temperature during plasticization may be set to 120 to 140°C.

[0078] The opaque region 20 may also be formed by partially foaming a resin such as PET of the container body 10. For example, a foaming agent may be impregnated into the material of the container body 10 in advance, and the preform molding described in S100 may be performed, and only the portion of the preform corresponding to the opaque region 20 may be heated under temperature conditions at which the foaming agent foams, to form foam cells in the preform. Thereafter, blow molding may be performed in S200 while maintaining the foam cells, thereby forming the opaque region 20.

[0079] The foaming agent may be, for example, sodium carbonate or an inert gas, as long as it can form fine and uniform foam cells in the container body 10. The foam cells can be formed by a known method, such as the method described in JP-A-2009-262366.

[0080] When a multilayer preform is used, all layers or only an arbitrary part of the layers may be whitened to form the opaque region 20. For example, when the intermediate layer 14 is nylon in the three-layer structure shown in Fig. 4, only the intermediate layer 14 can be whitened by partially heating the multilayer preform at a temperature equal to or higher than the crystallization temperature of nylon and lower than the crystallization temperature of PET (e.g., 120 to 140°C). When the intermediate layer 14 is recycled PET, only the intermediate layer 14 can be whitened by partially heating the multilayer preform at a temperature equal to or higher than the crystallization temperature of recycled PET and lower than the crystallization temperature of PET (e.g., 120 to 140°C).

[0081] In addition, instead of / in addition to partially heating the preform, whitening may be promoted by making the moisture content of the material of the intermediate layer 14 (e.g., nylon or recycled PET) higher than that of the inner and outer PET layers (i.e., PET layer 12 and PET layer 16).

[0082] Further, instead of / in addition to the method described above, an opacifying step S300 in Fig. 8 may be performed in each of the molding steps S100 to S200. That is, in these molding steps, polyethylene terephthalate (PET) and an opaque material may be used to mold a container having a transparent container body 10 capable of holding contents and an opaque region 20 provided on at least a part of the outer surface or inner surface of the container body 10. For example, the opacifying step may be performed together with the molding step using a method such as two-color molding, compression molding, or integral molding of a film.

[0083] When two-color molding (also called double molding) is utilized, primary injection molding may be performed using PET as the material to first form a single-layer preform corresponding to the container body 10, and then secondary injection molding may be performed using an opaque material so that a portion of the outer surface or inner surface of the single-layer preform is covered with the opaque material. This results in a two-layer preform with PET as the base material and a portion that is two-layered.

[0084] The two-layer preform is then blow molded to obtain a container having a transparent container body and an opaque region 20 provided on at least a portion of the outer surface or inner surface of the container body. The area of ​​the preform coated with the opaque material will later become the opaque region 20.

[0085] When compression molding is utilized, an opaque material may be molded together with the container body 10 to form a container having an opaque region 20 provided on at least a portion of the outer surface or inner surface of the container body 10. When integrally molding a film, a film or the like that forms the opaque region 20 may be integrally molded with the preform by, for example, disposing a heat-shrinkable material such as a partially opaque film around the preform and heat-shrinking it.

[0086] In Example 1 and Examples 3 to 26 shown below, S200 and S300 in Fig. 8 were performed in parallel. That is, the opaque region 20 was formed during blow molding. In Example 2, S300 was performed after S200 in Fig. 8. That is, the opaque region 20 was formed after blow molding. [Example 1] A single-layer preform was molded using a commercially available polyethylene terephthalate resin material, and the preform was then subjected to biaxial blow molding to produce a PET bottle-shaped container. A mold heated to 160°C was pressed against a portion of the body of the PET bottle to form an opaque region. The haze value of the opaque region was 20.

[0087] [Example 2] In Example 1, an opaque region was formed by laser irradiation instead of a heated mold. Specifically, a single-layer preform was molded using a commercially available polyethylene terephthalate resin material, and the preform was subjected to biaxial stretching blow molding to produce a container in the shape of a plastic bottle. An opaque region was formed in a part of the body of this plastic bottle container by laser irradiation (wavelength 9.3 μm, output 30 W). The haze value of the opaque region was 90.

[0088] [Example 3] Instead of the heated mold in Example 1, a mold roughened by sandblasting was used to roughen part of the outside of the container, forming an opaque region. Glass beads with a grain size of F400 according to JIS R6001 were used as the sandblasting agent, and the blasting pressure was 3 kgf / cm. 2 Sandblasting was done.

[0089] [Example 4] The same procedure as in Example 3 was carried out, except that glass beads having a particle size of F320 were used as the sandblasting agent.

[0090] [Example 5] The same procedure as in Example 3 was carried out, except that glass beads having a particle size of F100 were used as the sandblasting agent.

[0091] [Example 6] The same procedure as in Example 3 was carried out, except that glass beads having a particle size of F80 were used as the sandblasting agent.

[0092] [Example 7] The same procedure as in Example 3 was carried out, except that alumina particles having a particle size of F100 were used as the sandblasting agent.

[0093] [Example 8] The same procedure as in Example 3 was carried out, except that glass beads having a particle size of F70 were used as the sandblasting agent.

[0094] [Example 9] The same procedure as in Example 3 was carried out, except that glass powder with a particle size of F54 was used as the sandblasting agent.

[0095] [Example 10] The same procedure as in Example 3 was carried out, except that emery having a grain size of F60 was used as the sandblasting agent.

[0096] [Example 11] The same procedure as in Example 3 was carried out, except that alumina particles having a particle size of F46 were used as the sandblasting agent.

[0097] [Example 12] The same procedure as in Example 3 was carried out, except that emery having a particle size of F24 was used as the sandblasting agent.

[0098] [Example 13] The same procedure as in Example 3 was carried out, except that emery having a grain size of F36 was used as the sandblasting agent.

[0099] [Example 14] The same procedure as in Example 3 was carried out, except that emery having a grain size of F16 was used as the sandblasting agent.

[0100] [Example 15] A single-layer preform was molded using a commercially available polyethylene terephthalate resin material. The outside of the single-layer preform was further coated with low-density polyethylene and subjected to secondary injection molding to obtain a two-layer preform. The two-layer preform was subjected to biaxial stretching blow molding to produce a container in the shape of a plastic bottle. An opaque area was formed on a part of the outside of the container using a mold that had been sandblasted under the same conditions as in Example 3. [Example 16] The same procedure as in Example 15 was carried out, except that glass beads having a particle size of F80 were used as the sandblasting agent.

[0101] [Example 17] The same procedure as in Example 15 was carried out, except that glass beads having a particle size of F100 were used as the sandblasting agent.

[0102] [Example 18] The same procedure as in Example 15 was carried out, except that glass beads having a particle size of F320 were used as the sandblasting agent.

[0103] [Example 19] The same procedure as in Example 15 was carried out, except that glass beads having a particle size of F70 were used as the sandblasting agent.

[0104] [Example 20] The same procedure as in Example 15 was carried out, except that alumina particles having a particle size of F100 were used as the sandblasting agent. [Example 21] The same procedure was followed as in Example 15, except that emery having a particle size of F60 was used as the sandblasting agent.

[0105] [Example 22] The same procedure as in Example 15 was carried out, except that glass powder having a particle size of F54 was used as the sandblasting agent.

[0106] [Example 23] The same procedure as in Example 15 was carried out, except that alumina particles having a particle size of F46 were used as the sandblasting agent.

[0107] [Example 24] The same procedure was followed as in Example 15, except that emery having a particle size of F16 was used as the sandblasting agent.

[0108] [Example 25] The same procedure was followed as in Example 15, except that emery having a particle size of F24 was used as the sandblasting agent.

[0109] [Example 26] The same procedure was followed as in Example 15, except that emery having a particle size of F36 was used as the sandblasting agent.

[0110] The arithmetic mean height (Ra), mean length (RSm), and haze of the opaque region were measured for the containers produced in Examples 3 to 26. The measurement results are shown in the following Table 1. The units of Ra and RSm are μm. [Table 1] [Table 1]

[0111] As shown in Table 1, in the single layer preform, Examples 5 to 8 in which Ra / RSm is greater than 0.001 and less than 0.002 have higher haze than Examples 3 to 4 in which Ra / RSm is less than 0.001. Examples 9 to 14 in which Ra / RSm is greater than 0.002 have even higher haze than Examples 5 to 8. Also, in the single layer preform, it was shown that when Ra exceeds 0.8 μm, the haze is generally good.

[0112] In the two-layer preform, Examples 18 to 20 in which Ra / RSm is greater than 0.01 and less than 0.02 have higher haze than Examples 15 to 17 in which Ra / RSm is less than 0.01. Examples 21 to 26 in which Ra / RSm is greater than 0.02 have even higher haze than Examples 18 to 20. Also, in the two-layer preform, it was shown that when Ra exceeds 1.8 μm, the haze is generally good.

[0113] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0114] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the methods shown in the claims, specifications, and drawings, is not specifically indicated as "before," "prior to," etc., and may be realized in any order, unless the result of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, it does not mean that it is essential to perform the process in this order. An example of an embodiment of the present invention is shown as an item. [Item 1] A transparent container body made of polyethylene terephthalate (PET) capable of holding contents; An opaque area provided on a part of an outer surface or an inner surface of the container body; a printing layer including a colorant provided on at least a portion of the opaque region; Equipped with PET container. [Item 2] The opaque areas are areas where the PET of the container body has been whitened. PET container as described in item 1. [Item 3] The opaque area is an area in which the PET of the container body is at least partially crystallized. PET containers as described in item 2. [Item 4] The opaque region is a roughened outer or inner surface of the container body. PET containers as described in item 2. [Item 5] The arithmetic mean roughness (Ra) of the roughened area is 0.05 to 20 μm. PET containers as described in item 4. [Item 6] The value of Ra / RSm, which is the arithmetic mean roughness (Ra) and mean length (RSm) of the roughened area, is 0.001 or more. PET container according to item 4 or 5. [Item 7] The opaque area is a region where the PET of the container body has been partially foamed. PET containers as described in item 2. [Item 8] The container body is The middle class, A PET layer made of polyethylene terephthalate sandwiching an intermediate layer; 8. The PET container according to any one of items 1 to 7, comprising: [Item 9] The middle layer comprises nylon or recycled PET. PET containers as described in item 8. [Item 10] The haze of the opaque region is 0.5 to 100. 10. The PET container according to any one of items 1 to 9. [Item 11] The heat-induced crystallinity of PET in the opaque region is 15%-80%; 11. The PET container according to any one of items 1 to 10. [Item 12] The total light transmittance of the opaque area is 85% or less; Total light transmittance is the average transmittance for light with wavelengths of 400 to 700 nm. 12. The PET container according to any one of items 1 to 11. [Item 13] The printing layer includes printed characters, The opaque area is provided at least on the border of the characters. 13. The PET container according to any one of items 1 to 12. [Item 14] Further comprising a recessed portion representing a letter or symbol formed on the outer surface of the container body; 14. The PET container according to any one of items 1 to 13. [Item 15] The letters or symbols in the recesses indicate information about the material of the container body, The printing layer represents information specific to the product sold using the PET container. PET container according to item 14. [Item 16] A molding step of molding a transparent container body capable of holding contents using polyethylene terephthalate (PET); an opacifying step of at least partially opacifying an exterior or interior surface of the container body; A printing step of forming a print layer on the opaque portion of the container body by an inkjet method; A method for manufacturing a PET container comprising the steps of: [Item 17] The opacifying step includes at least partially whitening the PET of the container body; Item 17. A method for producing a PET container according to item 16. [Item 18] The opacifying step includes at least partially crystallizing the PET of the container body; Item 18. A method for producing a PET container according to item 17. [Item 19] The opacifying step includes roughening the exterior or interior surface of the container body; Item 18. A method for producing a PET container according to item 17. [Item 20] The arithmetic mean roughness (Ra) of the roughened surface of the container body is 0.05 to 20 μm. Item 19. A method for producing a PET container according to item 19. [Item 21] The value of Ra / RSm, which is the arithmetic mean roughness (Ra) and mean length (RSm) of the roughened surface, is 0.001 or more. Item 21. The method for producing a PET container according to Item 19 or 20. [Item 22] The opacifying step involves partially foaming the PET of the container body; Item 18. A method for producing a PET container according to item 17. [Item 23] A molding step of molding a container using polyethylene terephthalate (PET) and an opaque material, the container having a transparent container body capable of holding contents and an opaque region provided on at least a part of an outer surface or an inner surface of the container body; A printing step of forming a printing layer on an opaque area of ​​the container by an inkjet method; A method for manufacturing a PET container comprising the steps of: [Item 24] The molding step is performed by injecting the opacifying material into the container body so as to cover the outer or inner surface of the container body by double molding. Item 24. A method for producing a PET container according to item 23. [Explanation of symbols]

[0115] 10 Container body 12 PET layers 14 Middle Class 16 PET layers 20 Opaque area 30 printing layer 35 Transparent area 40 Recess 100 containers

Claims

1. A transparent container body made of polyethylene terephthalate (PET) and capable of holding contents; An opaque area provided on a part of an outer surface or an inner surface of the container body; a printing layer including a colorant provided on at least a portion of the opaque region; Equipped with The opaque region is a whitened region obtained by at least partially crystallizing the PET of the container body, the haze of the opaque region is 0.5 to 100; The heat-induced crystallinity of the PET in the opaque region is between 15% and 80%; PET container.

2. The thickness of the opaque region is 0.05 to 1 mm.

2. The PET container according to claim 1.

3. The container body includes: The middle class, PET layers made of polyethylene terephthalate sandwiching the intermediate layer; 2. The PET container of claim 1 comprising:

4. the intermediate layer comprises nylon or recycled PET; The PET container according to claim 3.

5. The total light transmittance of the opaque region is 85% or less; The total light transmittance is an average of the transmittance for light having a wavelength of 400 to 700 nm.

5. The PET container according to claim 1 .

6. the printing layer includes printed characters; The opaque area is provided at least on the edge of the character.

6. The PET container according to claim 1 .

7. The container further includes a recess having a letter or symbol formed on the outer surface of the container body.

7. The PET container according to claim 1 .

8. The letters or symbols in the recesses represent information regarding the material of the container body, The printed layer represents information specific to a product sold using the PET container.

8. The PET container according to claim 7.

9. A molding step of molding a transparent container body capable of holding contents using polyethylene terephthalate (PET); an opacifying step of forming an opaque region by at least partially opacifying the outer surface or the inner surface of the container body; a printing step of forming a print layer on the opaque portion of the container body by an inkjet method; Equipped with The opacifying step includes whitening the PET of the container body by at least partially crystallizing it; the haze of the opaque region is from 0.5 to 100; The heat-induced crystallinity of the PET in the opaque region is between 15% and 80%; A method for manufacturing a PET container.

10. The thickness of the opaque region is 0.05 to 1 mm. The method for producing a PET container according to claim 9.

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