Recycled resin composition, molded container, bottle, and tube

Abstract

To provide a molded container excellent in color, moldability and drop strength by using a recycled resin composition using a PET bottle cap, and to widen the range of applications for recycling using the PET bottle cap. [Solution] The problem is solved by a recycled resin composition containing a recycled resin (X1) obtained using PET bottle caps, a resin (X2) other than the recycled resin (X1), and a white pigment (Y1), wherein the recycled resin composition has a melt mass flow rate (MFR) of 0.1 to 5 g / 10 min at 190°C, the recycled resin (X1) contains polyethylene and polypropylene, and the polyethylene content:polypropylene content is 70:30 to 95:5, and the white pigment (Y1) is titanium oxide that has been subjected to a surface treatment with any one selected from the group consisting of aluminum oxide, silicon dioxide, and siloxane.

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to recycled resin compositions, molded containers, bottles, and tubes, and methods for producing molded containers. [Background technology]

[0002] Due to their properties of transparency, design, light weight, and safety, polyester bottles are used in many fields, including food, healthcare, cosmetics, and medicine, and their usage is expanding.In addition, with the recent promotion of a recycling-oriented society, the polyester used to make polyester bottles is being recycled into bottles, daily necessities, clothing, and other products, achieving a high recycling rate.

[0003] For example, Patent Document 1 describes a biaxially oriented polyester film roll obtained by winding up a biaxially oriented polyester film made of a polyester resin composition containing particles and a polyester resin made from recycled PET bottles.

[0004] On the other hand, polyolefin resin is often used for the caps of polyester bottles because it is highly resistant to the contents and easy to mold. In addition, polyolefin resin is colored in a wide variety of colors using pigments to enhance the design of the caps. For this reason, currently, PET bottle caps are mostly only used for recycling in applications where color is not important, such as pallets and building materials.

[0005] Regarding the recycling of PET bottle caps, for example, Patent Document 2 describes a method for producing recycled building materials, which is characterized by melting and kneading waste plastic, crushed seashells, and polypropylene, and extruding the mixture using an extruder.

[0006] In order to expand the use of recycled materials, it is possible to separate PET bottle caps by color after collection, or to separate and remove the coloring agents during recycling. However, this is difficult to put into practical use due to the complexity and cost involved.

[0007] Furthermore, the recycling of PET bottle caps involves crushing and washing the collected caps to turn them into resin flakes, which are then melted, kneaded, and granulated in an extruder or other equipment. However, impurities such as ink remaining on the top surface of the caps and the thermal history of the thermoplastic resin can cause molding defects such as uneven film thickness and reduced drop strength when the caps are molded into a molded product. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2022 / 049998 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-308869 Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, an embodiment of the present invention is a recycled resin composition made from recovered PET bottle caps, and an object of the present invention is to provide a molded container that has excellent moldability, color, and drop strength using this recycled resin composition. The recycled resin composition of the present invention can broaden the range of applications for recycling PET bottle caps. [Means for solving the problem]

[0010] The present invention includes the following embodiments, but is not limited to the following embodiments. (1) A recycled resin composition containing a recycled resin (X1) obtained from a PET bottle cap, a resin (X2) other than the recycled resin (X1), and a white pigment (Y1), The recycled resin composition has a melt mass flow rate (MFR) of 0.1 to 5 g / 10 min at 190°C, the recycled resin (X1) contains polyethylene and polypropylene, and the polyethylene content (parts by mass):polypropylene content (parts by mass) is 70:30 to 95:5, A recycled resin composition, wherein the white pigment (Y1) is titanium oxide that has been surface-treated with any one selected from the group consisting of aluminum oxide, silicon dioxide, and siloxane. (2) The recycled resin composition according to (2), wherein the recycled resin (X1) has a melt mass flow rate (MFR) at 190° C. of 0.1 to 10 g / 10 min. (3) The recycled resin composition according to (1) or (2), further comprising at least one pigment (Y2) selected from the group consisting of monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, and quinacridone violet. (4) The recycled resin composition according to any one of (1) to (3), wherein the content of the white pigment (Y1) is 0.5 to 25% by mass based on 100% by mass of the recycled resin composition. (5) A molded container produced using the recycled resin composition according to any one of (1) to (4). (6) The molded container according to (5), wherein the lightness (L* value) of at least a part of the surface is 60.0 or more. (7) A bottle, which is the molded container described in (5). (8) A tube, which is the molded container according to (5). (9) A method for producing a molded container, comprising a step of molding the recycled resin composition according to any one of (1) to (4) by a blow molding method or an extrusion molding method. [Effects of the Invention]

[0011] According to one embodiment of the present invention, a molded container having excellent moldability, color, and drop strength is provided as a new application of recycled resin obtained from PET bottle caps. According to another embodiment of the present invention, there is provided a recycled resin composition suitable for molded containers. Furthermore, according to another embodiment of the present invention, there is provided a method for producing molded containers as a new use of recycled resin obtained from PET bottle caps. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present invention will be described. The embodiment of the present invention is not limited to the following. In this specification, a numerical range specified using "to" includes the numerical values before and after "to" as the lower and upper limit values of the range. Unless otherwise noted, each component may be used independently, either alone or in combination of two or more. In addition, "PET bottle cap" is sometimes referred to as "cap," and pigment derived from PET bottle cap refers to the pigment contained in the PET bottle cap. Also, "CI" below stands for Color Index (CI). The melt mass flow rate (MFR) can be determined in accordance with JIS K 7210-1:2014. The numerical values described in this specification refer to values obtained by the method described in the Examples below.

[0013] <Recycled resin composition> In an embodiment of the present invention, the recycled resin composition contains a recycled resin (X1) obtained using PET bottle caps, a resin (X2) other than the recycled resin (X1), and a white pigment (Y1), and has a melt mass flow rate (MFR) at 190°C of 0.1 to 5 g / 10 min. The recycled resin (X1) contains polyethylene and polypropylene, and the polyethylene content (parts by mass):polypropylene content (parts by mass) is 70:30 to 95:5, and the white pigment (Y1) is titanium oxide that has been surface-treated with any one selected from the group consisting of aluminum oxide, silicon dioxide, and siloxane.

[0014] PET bottle caps have a unique color for each product from the viewpoints of design, identification, etc., and are formed from a resin composition containing a colorant corresponding to that color. When a recycled resin composition is obtained by collecting various used PET bottle caps, the recycled resin composition contains many types of colorants and recycled resin. Such recycled resin compositions have limited recycling applications due to the color imparted by the colorant.

[0015] In contrast, embodiments of the present invention, by using a specific composition, can provide a recycled resin composition that has excellent moldability, color, and drop strength even when using collected PET bottle caps without sorting or separation, thereby finding a new recycling application for PET bottle caps. According to embodiments of the present invention, it is possible to reduce PET bottle cap waste, thereby reducing environmental impact and contributing to the realization of a resource-circulating society. Furthermore, from the perspective of manufacturing molded containers, this has the effect of reducing raw material costs, allowing containers to be manufactured inexpensively, and also resulting in excellent design.

[0016] The melt mass flow rate (MFR) of the recycled resin composition is 0.1 to 5 g / 10 min, preferably 0.2 to 4.5 g / 10 min, and more preferably 0.3 to 4.0 g / 10 min. A melt mass flow rate (MFR) within this range is preferable because it allows a molded container to be obtained that is superior in formability and drop strength.

[0017] The melt mass flow rate of the recycled resin composition can be controlled by the type of PET bottle cap used, the types and amounts of resin (X2), pigment (Y1) and other pigments, and the kneading conditions of the recycled resin composition.

[0018] The type of resin used for the caps varies depending on the collection conditions, such as the season and region, in which used PET bottles are collected. For example, caps for PET bottles for cold drinks are often made of polyethylene, while caps for PET bottles for hot drinks are often made of polypropylene. Also, PET bottle caps are sometimes sorted by color using a color sorting device. By combining these caps and using them for recycling, the content ratio of polyethylene and polypropylene in the recycled resin and the melt mass flow rate (MFR) can be selected to fall within the above ranges.

[0019] The mass ratio of the polyethylene / polypropylene contents (PE / PP) in the recycled resin composition is preferably 0.5-300, more preferably 1-100, and even more preferably 3-30. Within this range, the moldability and drop strength can be improved.

[0020] <Resin (X)> The recycled resin composition of the present embodiment contains a recycled resin (X1) obtained using PET bottle caps, and a resin (X2). The recycled resin (X1) is a resin containing polyethylene and polypropylene, with the polyethylene content (parts by mass):polypropylene content (parts by mass) being 70:30 to 95:5. Resin (X2) is a resin other than the recycled resin (X1). By including the resin (X2) in addition to the recycled resin (X1), it is possible to provide a recycled resin composition that has excellent drop strength while maintaining a high recycling rate and good moldability.

[0021] [Recycled resin (x1)] The recycled resin (X1) is a resin obtained using PET bottle caps. Polyolefin resins are generally used as materials for PET bottle caps, and polyethylene (PE) and / or polypropylene (PP) are mainly used. Examples of polyethylene include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), etc., with high-density polyethylene being preferred. The recycled resin (X1) contains polyethylene and polypropylene, and preferably high-density polyethylene and polypropylene. This tends to result in a molded container with superior drop strength.

[0022] The content ratio of polyethylene and polypropylene in the recycled resin (X1) is polyethylene content (parts by mass):polypropylene content (parts by mass)=70:30 to 95:5. The ratio is more preferably 75:25 to 92.5:7.5, and even more preferably 80:20 to 90:10. By ensuring that the content is within this range, it is possible to provide a molded container that is more excellent in moldability and drop strength while increasing the recycling rate of the recycled resin composition. The mass ratio of the polyethylene and polypropylene content of the recycled resin (X1) can be determined by heat pressing the cap or recycled material at 200°C for 30 seconds to form a thin film, and measuring it by the transmission method using an infrared spectrophotometer (FT / IR-4100 manufactured by JASCO Corporation). 719cm from PE -1 and the PP-derived 841 cm -1 A calibration curve can be created by comparing the peak heights, and the polyethylene to polypropylene content ratio (PP:PE) can be calculated.

[0023] The recycled resin (X1) preferably has a melt mass flow rate (MFR) at 190° C. of 0.1 to 10 g / 10 min, more preferably 0.2 to 9 g / 10 min, and even more preferably 0.3 to 8 g / 10 min. The MFR of the recycled resin (X1) is a value determined by measuring resin flakes obtained by crushing and washing recovered PET bottle caps, or a resin composition obtained by melting and kneading these flakes and forming them into pellets, at 190°C under a load of 2.16 kg in accordance with JIS K 7210-1:2014. Specifically, it can be determined by the method described in the Examples. When the melt mass flow rate (MFR) of the recycled resin (X1) is within this range, it is possible to provide a molded container having better moldability and drop strength while increasing the recycling rate of the recycled resin composition.

[0024] The content of the recycled resin (X1) may be, for example, 5 to 95% by mass, 10 to 95% by mass, or 50 to 70% by mass based on the recycled resin composition (100% by mass). When it is 95% by mass or less, better moldability can be maintained in blow molding or extrusion molding. When it is 50% by mass or more, the proportion of the recycled resin can be increased, which is preferable.

[0025] [Resin (X2)] Resin (X2) is a resin other than the recycled resin (X1). Resin (X2) may be a resin used for molding a container, and is preferably a thermoplastic resin. It may also be a recycled resin other than the recycled resin (X1), or a virgin resin derived from petroleum resources. Virgin resins are preferred in terms of moldability.

[0026] Resin (X2) may be a resin compatible with recycled resin (X1), and examples of compatible resins include polyester, polystyrene, polyolefin, and aromatic nylon. Examples of polyolefins include polyethylenes such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE), polypropylene, ethylene-vinyl acetate copolymers, ethylene-α-olefin random copolymers, and ionomer resins. Resin (X2) preferably contains polyolefin, more preferably polyethylene, polypropylene, or both, and even more preferably polyethylene. If the polyethylene is high-density polyethylene, it is possible to provide a molded container with excellent drop strength, and this is preferable.

[0027] The melt mass flow rate (MFR) of the resin (X2) is, for example, preferably 0.01 to 50 g / 10 min, more preferably 0.1 to 10 g / 10 min. When the melt mass flow rate (MFR) is in this range, a molded container with better moldability and drop strength can be provided.

[0028] The content of resin (X2) may be, for example, 2 to 900 parts by mass, 5 to 250 parts by mass, or 10 to 100 parts by mass, relative to 100 parts by mass of recycled resin (X1). When the content is 2 parts by mass or more, good moldability can be maintained in blow molding or extrusion molding. When the content is 100 parts by mass or less, the proportion of recycled resin can be increased, which is preferable.

[0029] <Pigment (Y)> The recycled resin composition of the present embodiment contains a white pigment (Y1) and may also contain other pigments.

[0030] [White pigment (Y1)] The white pigment (Y1) is titanium oxide that has been surface-treated with any one selected from the group consisting of aluminum oxide, silicon dioxide, and siloxane. By including such a white pigment (Y1), not only can the resin composition have excellent hue and opacity and be expanded to other uses such as molded containers, making them recyclable, but also can suppress outgassing from the resin composition, thereby providing molded containers with better moldability and drop strength.

[0031] The white pigment (Y1) may be a pigment derived from a PET bottle cap contained in the recycled resin composition. The white pigment (Y1) derived from a PET bottle cap may be referred to as "pigment (Y1a)," and a pigment other than the pigment (Y1a) derived from a PET bottle cap may be referred to as "pigment (Y1b)."

[0032] Surface treatments of titanium oxide are broadly classified into treatments using inorganic compounds and treatments using organic compounds. Examples of inorganic compounds include aluminum oxide, silicon dioxide, zirconium oxide, etc. Examples of organic compounds include siloxane, silane coupling agent, polyhydric alcohol, titanium coupling agent, alkanolamine or derivative thereof, and higher fatty acid or metal salt thereof, etc.

[0033] The recycled resin composition of the present invention is characterized by containing a white pigment (Y1) that is titanium oxide that has been surface-treated with any one selected from the group consisting of aluminum oxide, silicon dioxide, and siloxane. The surface treatments with aluminum oxide, silicon dioxide, and siloxane may be a combination of multiple treatments, and it is preferable that the surface be at least surface-treated with aluminum oxide. By containing such a white pigment (Y1), a molded container that is excellent in moldability, hue, and drop strength can be provided.

[0034] Aluminum oxide is an oxide of aluminum, and a water-soluble aluminum salt is preferred. Specific examples include aluminum chloride, aluminum sulfate, and sodium aluminum nitrate aluminate. Titanium oxide can also be coated with alumina (Al2O3) by adding sulfuric acid or chlorine. Examples of silicon dioxide include sodium silicate and silicon tetrachloride. Examples of the siloxane include dimethylpolysiloxane, methylhydrogenpolysiloxane, and alkyl-modified polysiloxane.

[0035] The white pigment (Y1) may be further surface-treated with a compound other than any one selected from the group consisting of aluminum oxide, silicon dioxide, and siloxane. The other compounds include inorganic compounds such as zirconium oxide, and organic compounds such as silane coupling agents.

[0036] The content of the white pigment (Y1) is, for example, preferably 0.25 to 30% by mass, more preferably 0.5 to 25% by mass, and even more preferably 1 to 10% by mass, based on the recycled resin composition (100% by mass). When the content is 0.25% by mass or more, the hue and shielding properties become better, and the contents of the container tend to be sufficiently concealed. When the content is 30% by mass or less, the drop impact strength of the molded container can be maintained better. The white pigment (Y1) in this case is the total amount of the white pigment (pigment (Y1a)) derived from the PET bottle cap and the pigment (Y1b) other than the pigment (Y1a) derived from the PET bottle cap.

[0037] [Other pigments] The recycled resin composition of the present invention may contain other pigments. The other pigments may be pigments other than the white pigment (Y1) and may be pigments derived from PET bottle caps, or may further contain pigments other than the pigments derived from PET bottle caps.

[0038] Other pigments include organic pigments such as azo pigments, quinacridone pigments, perylene pigments, isoindolinone pigments, diketopyrrolopyrrole pigments, and phthalocyanine pigments, as well as inorganic pigments.

[0039] Examples of azo pigments include monoazo yellow, monoazo red, monoazo orange, disazo yellow, and disazo orange. Examples of quinacridone pigments include quinacridone red, quinacridone violet, and quinacridone magenta. Examples of perylene pigments include perylene red and perylene orange. Examples of isoindolinone pigments include isoindolinone orange and isoindolinone yellow. Examples of diketopyrrolopyrrole pigments include diketopyrrolopyrrole red and diketopyrrolopyrrole orange. Examples of phthalocyanine pigments include phthalocyanine blue and phthalocyanine green.

[0040] Examples of inorganic pigments include calcium carbonate, barium sulfate, zinc sulfide, iron oxide, ultramarine, cobalt blue, nickel titanium yellow, bismuth yellow, carbon black, and pearl pigments.

[0041] Specific examples of azo pigments include CI Pigment Yellow 93, 95, 150, 151, 168, 169, 180, and 181, and CI Pigment Red 144, 208, and 214. Specific examples of quinacridone pigments include CI Pigment Red 122, 207, CI Pigment Bio Red 19, etc. Specific examples of perylene pigments include CI Pigment Red 149 and 178. Specific examples of isoindolinone pigments include CI Pigment Yellow 109, 110, 139, CI Pigment Orange 61, etc. Specific examples of diketopyrrolopyrrolopyrrole pigments include CI Pigment Red 254, 264, and CI Pigment Orange 71. Examples include:

[0042] A specific example of Pigment Yellow 93 is Cromophtal Yellow 3GNP (manufactured by BASF), a specific example of Pigment Yellow 95 is Cromophtal Yellow GRP (manufactured by BASF), a specific example of Pigment Yellow 150 is Binamon Yellow 115002 (manufactured by Heubach), a specific example of Pigment Yellow 151 is PV Fast Yellow H4G (manufactured by Clariant), and a specific example of Pigment Yellow 168 is Lionol Yellow K5G (manufactured by Toyokawa). A specific example of Pigment Yellow 169 is Lionol Yellow K2R (manufactured by Toyocolor Co., Ltd.), a specific example of Pigment Yellow 180 is PV Fast Yellow HG (manufactured by Clariant), a specific example of Pigment Yellow 181 is PV Fast Yellow H3R (manufactured by Clariant), a specific example of Pigment Red 144 is Cromophtal Red BRN (manufactured by BASF), a specific example of Pigment Red 208 is Grafthol Red HF2B (manufactured by B A specific example of Pigment Red 214 is Chromophthal Red BN (manufactured by BASF), a specific example of Pigment Red 122 is Fastgen Super Magenta RE03 (manufactured by DIC), Binamon Red 312201 (manufactured by Heubach), a specific example of Pigment Red 207 is Fastgen Super Scarlet GK (manufactured by DIC), a specific example of Pigment Bio Red 19 is Chromophthal Red 2020 (manufactured by BASF), Pigment Red A specific example of Pigment Red 149 is Paliogen Red K3580 (manufactured by BASF), a specific example of Pigment Red 178 is Paliogen Red K3911HD (manufactured by BASF), a specific example of Pigment Red 254 is Chromophtal Red 2028 (manufactured by BASF), a specific example of Pigment Red 264 is Irgazin DPP Rubin TR (manufactured by BASF), and a specific example of Pigment Orange 71 is Chromophtal DPP Orange TRP (manufactured by BASF).

[0043] The other pigments may include at least one pigment (Y2) selected from the group consisting of monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, and quinacridone violet, which are generally commonly used in PET bottle caps. The pigment (Y2) may be a pigment derived from a plastic bottle cap, or may further contain a pigment other than the pigment derived from a plastic bottle cap. The pigment (Y2) derived from a plastic bottle cap may be referred to as "pigment (Y2a)," and the pigment (Y2) other than the pigment (Y2a) derived from a plastic bottle cap may be referred to as "pigment (Y2b)."

[0044] For example, the blue cap mainly uses phthalocyanine blue, the green cap mainly uses phthalocyanine green, the yellow cap mainly uses monoazo yellow, disazo yellow, or monoazo orange, and the red cap mainly uses quinacridone red, diketopyrrolopyrrolopyrrole red, or quinacridone violet. The pigment (Y2a) usually contains two or more pigments, for example, five or more, or ten or more pigments. The pigment (Y2a) and the pigment (Y2b) may contain the same pigment or may not contain the same pigment. Examples of the pigment (Y2a) include organic pigments and inorganic pigments. By using the recycled resin composition of the present invention, even recovered PET bottles containing the pigment (Y2) can be recycled and used to make molded containers, thereby expanding the range of recycled applications.

[0045] The content of the pigment (Y2) is, for example, preferably 0 to 15% by mass, more preferably 0 to 10% by mass, and even more preferably 0 to 5% by mass, based on the recycled resin composition (100% by mass). When the content is 15% by mass or less, the color can be maintained in a good state. Alternatively, the content may be 0.01% by mass or more.

[0046] When the other pigment is an organic pigment, its content may be, for example, 0 to 15 mass%, 0 to 10 mass%, 0 to 5 mass%, 0 to 4 mass%, or 0 to 3 mass%, based on the recycled resin composition (100 mass%). When it is 15 mass% or less, the appearance of the molded container tends to be better.

[0047] When the other pigment is an inorganic pigment, the content thereof is, for example, 0 to 25 mass%, 0 to 20 mass%, 0 to 10 mass%, 0 to 8 mass%, or 0 to 6 mass% relative to the recycled resin composition (100 mass%). Within this range, the drop impact strength of the bottle can be maintained better.

[0048] <Optional ingredients> The recycled resin composition may contain optional components such as additives as needed, such as metal soaps of alkali metals, alkaline earth metals, zinc, etc., antioxidants, ultraviolet absorbers, light stabilizers, metal deactivators, surfactants such as nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants, antistatic agents, and flame retardants such as halogen-based, phosphorus-based, and metal oxide-based flame retardants.

[0049] Examples of metallic soaps include calcium stearate, magnesium stearate, barium stearate, zinc stearate, aluminum stearate, lithium stearate, calcium laurate, zinc laurate, and magnesium laurate.

[0050] Examples of antioxidants include phenols and phosphites. Examples of phenols include diethyl [[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Examples of phosphites include tris(2,4-di-tert-butylphenyl)phosphite and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-diphosphite.

[0051] Examples of UV inhibitors include benzotriazoles and triazines. Examples of benzotriazoles include 2,2-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6[(2H-benzotriazol-2-yl)phenol]], 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, and 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol. Examples of triazines include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol.

[0052] Examples of light stabilizers include hindered amines, such as bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], and polycondensates of dibutylamine, 1,3,5-triazine, N,N-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine, and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine.

[0053] Examples of metal deactivators include 2,3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide.

[0054] The content of the optional components is, for example, 0.01 to 5% by mass, preferably 0.05 to 3% by mass, and more preferably 0.1 to 1% by mass, based on the recycled resin composition (100% by mass). When the content is 0.01% by mass or more, the effect of the added material can be fully exerted. When the content is 5% by mass or less, molding can be performed while suppressing migration such as bleed-out.

[0055] <Method of manufacturing recycled resin composition> The recycled resin composition can be obtained, for example, by a production method including crushing PET bottle caps to obtain a crushed product (crushing step), and melt-kneading the crushed product to obtain a kneaded product (kneading step). The production method may further include optional steps such as washing the PET bottle caps, drying the washed PET bottle caps, washing the crushed product, drying the washed crushed product, separating the crushed product, adding optional components, and molding the kneaded product into a shape such as pellets.

[0056] The method for crushing the packaging material in the crushing step is not particularly limited, and examples thereof include methods using a jaw crusher, impact crusher, cutter mill, stamp mill, ring mill, roller mill, jet mill, and hammer mill.

[0057] In the kneading step, any component such as an additive may be added as necessary. The melt-kneading method is not particularly limited, and examples thereof include a method in which the components are mixed using a Henschel mixer, a tumbler, a disper, or the like, and then melt-kneaded using a batch mixer such as a kneader, a roll mill, a super mixer, a Henschel mixer, a Schuggie mixer, a vertical granulator, a high-speed mixer, a Farmatrix, a ball mill, a steel mill, a sand mill, a vibration mill, an attritor, or a Banbury mixer, a twin-screw extruder, a single-screw extruder, or a rotor-type twin-screw kneader. When the kneaded product is granulated into a shape such as pellets, a twin-screw extruder or a single-screw extruder can be preferably used.

[0058] In this way, the PET bottle caps are crushed and washed, and the resulting recycled material containing the recycled resin (X1) and the pigment (Ya) can be used as recycled resin pellets or the like. Such recycled material and resin (X2) can be melt-kneaded using a twin-screw extruder, a single-screw extruder, or the like by, for example, the following production method (i), production method (ii), or a combination thereof, to produce a recycled resin composition containing recycled resin (X1), resin (X2), and white pigment (Y1).

[0059] From the viewpoint of moldability and recycle rate, the blending amount of resin (X2) per 100 parts by mass of recycled material is preferably 2 to 900 parts by mass, more preferably 5 to 250 parts by mass, and even more preferably 10 to 100 parts by mass.

[0060] [Manufacturing method (i)] The method includes a step of melting and kneading a recycled material obtained from PET bottle caps, a resin (X2), and a white pigment (Y1b), The recycled material includes recycled resin (X1) and pigment (Ya), A method for producing a recycled resin composition, wherein the white pigment (Y1b) is titanium oxide that has been surface-treated with any one selected from the group consisting of aluminum oxide, silicon dioxide, and siloxane.

[0061] In this case, from the viewpoint of hue and drop strength, the blending amount of the white pigment (Y1b) is preferably 0.5 to 50 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the recycled material.

[0062] [Manufacturing method (ii)] The method includes a step of melting and kneading a recycled material obtained by using PET bottle caps with a resin (X2), The recycled material includes recycled resin (X1) and pigment (Ya), The pigment (Ya) contains a white pigment (Y1a), A method for producing a recycled resin composition, wherein the white pigment (Y1a) is titanium oxide that has been subjected to a surface treatment with any one selected from the group consisting of aluminum oxide, silicon dioxide, and siloxane.

[0063] The content of the white pigment (Y1a) may be 0 to 10% by mass based on the recycled resin composition.

[0064] ≪Molded container≫ The molded container has a recycled resin layer molded from the recycled resin composition of the present invention, and may have, for example, a single-layer structure or a multi-layer structure of the recycled resin layer as shown below. Recycled resin layer Resin layer L1 / recycled resin layer Resin layer L1 / adhesive layer / recycled resin layer Resin layer L1 / Resin layer L2 / Recycled resin layer Resin layer L1 / adhesive layer / resin layer L2 / adhesive layer / recycled resin layer

[0065] An adhesive layer is a layer that bonds two or more layers together, for example, when the two layers to be bonded have different melting points. Known adhesive layers include those formed using adhesives containing acid-modified polyolefins, ethylene-acrylic acid copolymer resins, ethylene-vinyl acetate copolymer resins, etc. Commercially available adhesives include Nucrel (manufactured by DuPont-Mitsui Polychemicals), Admer (manufactured by Mitsui Chemicals), and Mersen (manufactured by Tosoh Corporation).

[0066] The resin layer L1 and the resin layer L2 are layers having various functions, such as an innermost layer to prevent direct contact between the contents and the inner recycled resin layer containing recycled materials, a barrier layer, an outermost layer provided outside the outer layer to increase the smoothness of the container surface and further improve the design, etc. For example, the resin layer L1 and the resin layer L2 may each independently be a layer having the same composition as the inner layer or the outer layer.

[0067] <Shape, usage, etc.> The shape of the molded container may be any shape, such as a bottle, tube, cylinder, prism, or sphere. A bottle or tube shape is preferred. According to an embodiment of the present invention, a bottle or tube that is a single-layer or multi-layer molded container is obtained. The capacity of the molded container is not particularly limited and may be any capacity, such as 350 mL, 500 mL, 1000 mL, 1500 mL, or 2000 mL. The thickness of the entire molded container may be uniform or non-uniform. For example, when the molded container is a bottle, the thicknesses of the neck, shoulder, body, bottom, etc. of the bottle may be different from one another.

[0068] The shaped container is suitable for various uses such as detergents, cosmetics, medicines, food, medical products, etc. The shaped container is preferably a detergent bottle or a detergent tube.

[0069] <Brightness and yellowness> The lightness (L* value) of at least a portion of the surface of the molded container may be 60.0 or more. The lightness (L* value) is the L* value in the L*a*b* color system defined by the International Commission on Illumination (CIE) and can be measured using a colorimeter. The lightness (L* value) is preferably 70.0 or more, or 75.0 or more. It can be adjusted by the thickness of the recycled resin layer, etc. When the molded container is a bottle or tube, it is preferable that the lightness of at least the body portion satisfies the above range, and it is more preferable that the lightness of the entire bottle or tube satisfies the above range. The lightness may be 99.9 or less.

[0070] The formed container may have a yellowness index (YI value) of -15.0 to 15.0 on at least a portion of its surface. The yellowness index (YI value) is determined in accordance with JIS K 7373:2006 based on the XYZ color system defined by the International Commission on Illumination (CIE), and can be measured using a colorimeter. The yellowness index (YI value) is preferably -10.0 to 10.0, or -5.0 to 5.0. The yellowness index (YI value) can be adjusted by the thickness of the recycled resin layer, etc. When the formed container is a bottle or a tube, it is preferable that the yellowness index of at least the body portion satisfies the above range, and it is more preferable that the yellowness index of the entire bottle or tube satisfies the above range.

[0071] <Total light transmittance> The total light transmittance of at least a portion of the molded container may be 10.0% or less. The total light transmittance is preferably 5.0% or less, or 1.0% or less. The total light transmittance can be adjusted by the total light transmittances and thicknesses of the outer and inner layers. When the molded container is a bottle or a tube, it is preferable that the total light transmittance of at least the body portion satisfies the above range, and it is more preferable that the total light transmittance of the entire bottle or tube satisfies the above range.

[0072] <Thickness> When the molded container is a bottle, the thickness of the recycled resin layer may be preferably 500 to 3,000 μm, more preferably 700 to 2,500 μm, and even more preferably 900 to 1,500 μm. If it is 500 μm or more, the strength of the bottle can be maintained. If it is 3,000 μm or less, uniform blow molding can be achieved, which is preferable. In the case of a tube, the thickness may be preferably 100 to 1,000 μm, more preferably 150 to 800 μm, and even more preferably 200 to 600 μm. If the thickness is 100 μm or more, the strength of the tube can be maintained. If the thickness is 1,000 μm or less, a lightweight tube can be maintained, which is preferable.

[0073] The overall thickness of the container is 500 to 3,000 μm for bottles to achieve both blow moldability and strength, and 100 to 1,000 μm for tubes to achieve both lightness and strength.

[0074] The adhesive layer has a thickness of, for example, 10 to 100 μm. The resin layer L1 may have a thickness suited to the function, material, etc. of the resin layer L1, and may have a thickness suited to the function, material, etc. of the resin layer L2 ...

[0075] <Method for manufacturing molded container> A method for producing a molded container according to an embodiment of the present invention includes molding a recycled resin composition containing a recycled resin (X1), a resin (X2), and a white pigment (Y1) obtained from PET bottle caps by a blow molding method or an extrusion molding method. The blow molding method may be, for example, an injection blow molding method, and the extrusion molding method may be, for example, a coextrusion molding method.

[0076] The brightness, yellowness, and total light transmittance can be adjusted by changing the thickness of the recycled resin layer, etc.

[0077] The MFR can be determined in accordance with JIS K 7210:-1:2014. The total light transmittance can be measured in accordance with JIS K 7375:2008. Lightness (L* value) is the L* value in the L*a*b* color system defined by the International Commission on Illumination (CIE), and can be measured using a colorimeter. The yellowness index (YI value) is based on the XYZ color system defined by the International Commission on Illumination (CIE) and is determined in accordance with JIS K 7373:2006, and can be measured using a color difference meter.

[0078] <Brightness and yellowness> The lightness (L* value) of at least a portion of the surface of the molded container may be 60.0 or more. The lightness (L* value) is the L* value in the L*a*b* color system defined by the International Commission on Illumination (CIE) and can be measured using a colorimeter. The lightness (L* value) is preferably 70.0 or more, or 75.0 or more. When the molded container is a bottle or a tube, it is preferable that the lightness of at least the body satisfy the above range in terms of hue, and it is more preferable that the lightness of the entire bottle or tube satisfy the above range. The formed container may have a yellowness index (YI value) of -15.0 to 15.0 on at least a portion of its surface. The yellowness index (YI value) is determined in accordance with JIS K 7373:2006 based on the XYZ color system defined by the International Commission on Illumination (CIE), and can be measured using a colorimeter. The yellowness index (YI value) is preferably -10.0 to 10.0, or -5.0 to 5.0. When the formed container is a bottle or a tube, it is preferable that the yellowness index of at least the body of the container satisfies the above range in terms of hue, and it is more preferable that the yellowness index of the entire bottle or tube satisfies the above range.

[0079] <Total light transmittance> The total light transmittance of at least a portion of the molded container may be 10.0% or less. The total light transmittance is preferably 5.0% or less, or 1.0% or less. When the molded container is a bottle or a tube, from the viewpoint of design, it is preferable that the total light transmittance of at least the body portion satisfies the above range, and it is more preferable that the total light transmittance of the entire bottle or tube satisfies the above range.

[0080] The amounts of the recycled resin (X1), resin (X2), white pigment (Y1), and pigment (Y2) obtained by using PET bottle caps may be the amounts that correspond to the content ratios in the molded container of the above-described embodiment. [Example]

[0081] The embodiments of the present invention will be described with reference to examples. The embodiments of the present invention are not limited to the following examples. In the examples, "parts" means "parts by mass" and "%" means "% by mass".

[0082] The melt mass flow rate (MFR) of the recycled resin composition, the average particle size of the pigment, and the PE / PP of the recycled resin composition were measured as follows. <Melt Mass Flow Rate (MFR) Measurement Method> The melt mass flow rate was determined at 190°C under a load of 2.16 kg in accordance with JIS K 7210-1:2014.

[0083] <Average particle size of pigment> A sample was prepared by dispersing the pigment in isopropyl alcohol. The resulting dispersion was irradiated with laser light using a Nikkiso Microtrac HRA particle size distribution analyzer. The particle size distribution was determined by measuring the distribution pattern of the scattered light intensity as the laser light passed through the dispersion. Furthermore, the median diameter (50% diameter) on a volume basis was calculated from the particle size distribution value, and this was used as the average particle size.

[0084] <Recycled resin composition PE / PP> The recycled resin composition was heat-pressed at 200° C. for 30 seconds to form a thin film, which was then measured by a transmission method using an infrared spectrophotometer (FT / IR-4100 manufactured by JASCO Corporation). 719cm from PE -1 and the PP-derived 841 cm -1 A calibration curve was created by comparing the peak heights, and the polyethylene content / polypropylene content (PE / PP) was calculated.

[0085] <Recycled material 1> PET bottle caps containing the following pigment as pigment (Y2a) were mixed and pulverized, and the resulting pulverized material was fed into a twin-screw extruder (manufactured by Japan Steel Works) and melt-kneaded at 220°C to obtain recycled material 1. The composition of recycled material 1 and the MFR of the recycled resin (X1) contained therein were as follows: [Recycled resin (x1)] Polyethylene content (parts by weight): Polypropylene content (parts by weight) = 95:5 MFR of recycled resin (X1): 1.5g / 10min [Pigment (Y2a)] Monoazo Yellow, Disazo Yellow, Monoazo Orange, Quinacridone Red, Diketopyrrolopyrrolopyrrole Red, Phthalocyanine Green, Phthalocyanine Blue, Quinacridone Violet

[0086] <Recycled materials 2-19> Depending on the type of PET bottle cap used as the material, recycled materials 2 to 19 derived from PET bottle caps were produced in the same manner as recycled material 1, except that the conditions were changed as shown in Table 1. The term "multicolored caps" refers to the use of caps of various colors, such as blue, green, yellow, red, white, and blue, without any separation.

[0087] <20% recycled materials> A white PET bottle cap containing 1.0% by mass of white pigment (Y1a) was crushed, and the crushed material was fed into a twin-screw extruder (manufactured by The Japan Steel Works, Ltd.) and melt-kneaded at 220°C to obtain a recycled material 20. The composition of the recycled material 20 and the MFR of the recycled resin (X1) contained therein were as follows: [Recycled resin (x1)] Polyethylene content (parts by weight): Polypropylene content (parts by weight) = 85:15 MFR of recycled resin (X1): 1.5g / 10min [Pigment (Y1a)] Titanium oxide that has been surface-treated with any one selected from the group consisting of aluminum oxide, silicon dioxide, and siloxane.

[0088] Table 1 shows the MFR of the recycled resin (X1) contained in the recycled material and the mass ratio (PE:PP ratio) of the polyethylene content (parts by mass) to the polypropylene content (parts by mass).

[0089] [Table 1]

[0090] The raw materials used in the examples are as follows. <Resin (X2)> (X2-1) HDPE1 (Hi-Zex 6203B, manufactured by Prime Polymer Co., Ltd., MFR: 0.36 g / 10 min) (X2-2) HDPE2 (Hi-Zex 8200B, manufactured by Prime Polymer Co., Ltd., MFR: 0.03 g / 10 min) (X2-3) LLDPE (Neozex 2006H, manufactured by Prime Polymer Co., Ltd., MFR: 0.63 g / 10 min) (X2-4) LDPE (Petrothene 170K, manufactured by Tosoh Corporation, MFR: 1.0 g / 10 min) (X2-5) PP (Novatec PP EA9 MFR: 0.5g / 10min, manufactured by Japan Polypropylene Corporation)

[0091] <White pigment (Y1), etc.> (Y1-1) Titanium oxide (Venator Corporation, Chronos 2230, average particle size: 0.37 μm, surface treatment: aluminum oxide, silicon dioxide, siloxane) (Y1-2) Titanium oxide (Ishihara Sangyo Kaisha, Ltd. CR-80, average particle size: 0.25 μm, surface treatment: aluminum oxide, silicon dioxide) (Y1-3) Titanium oxide (Sakai Chemical Industry Co., Ltd. D-962, average particle size: 0.26 μm, surface treatment: aluminum oxide, siloxane) (Y1-4) Titanium oxide (Ishihara Sangyo Kaisha, Ltd., Typec CR-95, average particle size: 0.28 μm, surface treatment: aluminum oxide, polyol) (Y1'-5) Titanium oxide (Teika Corporation JR, average particle size: 0.27 μm, surface treatment: none) (Y1'-6) Titanium oxide Synthesis Example 1 below (average particle size: 0.25 μm, surface treatment: polyol)

[0092] [Synthesis Example 1] Rutile-type titanium oxide particles with an average particle size of 0.25 μm were pulverized in a jet mill, and 0.5% by mass of trimethylolpropane was added and mixed with the titanium oxide particles to coat them, thereby obtaining Y1′-6.

[0093] [Example 1] 50 parts of recycled material 1, 47 parts of resin (X2-1) "HDPE1 (Hi-Zex 6203B manufactured by Prime Polymer Co., Ltd., MFR: 0.36 g / 10 min)", and 3 parts of white pigment (Y1-1) "titanium oxide (Kronos 2220 manufactured by Benatar, average particle size: 0.25 μm, surface treatment: aluminum oxide, silicon dioxide, siloxane)" were charged into a twin-screw extruder (manufactured by The Japan Steel Works), and melt-kneaded at 220°C to obtain pellet-shaped recycled resin composition 1.

[0094] Using the recycled resin composition 1, direct blow molding was performed at a temperature of 220°C using a direct multilayer blow molding machine (manufactured by Nissei ASB Co., Ltd.) to produce a blow-molded bottle consisting of a single recycled resin layer. The blow-molded container was a cylindrical bottle with a capacity of 500 mL and a body diameter of 70 mm, and molding was performed so that the total thickness at the center of the body (near the center between the shoulder and bottom of the container) was 1,000 μm.

[0095] [Examples 2 to 35, Comparative Examples 1 to 8] Recycled resin compositions 2 to 43 were produced in the same manner as recycled resin composition 1, except that the types and amounts (parts by mass) of recycled materials, resin (X2), pigment (Y1), etc. were changed as shown in Tables 2 and 3, respectively. Blow-molded bottles consisting of a single recycled resin layer were produced in the same manner as in Example 1.

[0096] The titanium oxide content (mass%) in the resin compositions of Examples 34 and 35 and Comparative Example 8 was calculated by calcining the resulting recycled resin compositions at 700°C for 20 minutes and then performing elemental analysis of the residue using an energy dispersive X-ray fluorescence analyzer EDX-7000 manufactured by Shimadzu Corporation.

[0097] [Example 42] Direct blow molding was performed at a temperature of 220°C using a direct multilayer blow molding machine (manufactured by Nissei ASB Co., Ltd.) so that the thickness at the center of the body (near the center of the shoulder and bottom of the container) was 475 μm for the resin layer L1 and recycled resin layer, and 50 μm for the adhesive layer, to produce a blow-molded bottle with a multilayer structure of resin layer L1 / adhesive layer / recycled resin layer. HDPE (Hi-Zex 6008B, manufactured by Prime Polymer Co., Ltd.) was used for the resin layer L1, recycled resin composition 3 was used for the recycled resin layer, and modified polyolefin (Admer NF518, manufactured by Mitsui Chemicals, Inc.) was used for the adhesive layer.

[0098] [Example 43] Direct blow molding was performed at a temperature of 220°C using a direct multilayer blow molding machine (manufactured by Nissei ASB Co., Ltd.) so that the thickness at the center of the body (near the center of the shoulder and bottom of the container) of the resin layer L1 and recycled resin layer was 500 μm, producing a blow-molded bottle with a multilayer structure of resin layer L1 / recycled resin layer. HDPE (Hi-Zex 6008B, manufactured by Prime Polymer Co., Ltd.) was used for the resin layer L1, and recycled resin composition 3 was used for the recycled resin layer.

[0099] In the recycled resin compositions 1 to 40, the total content of pigment Ya was 0.1 to 5 mass % based on the recycled resin composition.

[0100] <Evaluation of molded containers> The molded containers obtained in the examples and comparative examples were evaluated according to the following criteria. The evaluation results are shown in Tables 2 to 4. The evaluation was made on a three-level scale of ◯, △, and ×, with ◯ and △ being practical.

[0101] [Moldability] Three 3 cm square cuts were taken from the centre of the body of the molded container, and the thickness was measured with a vernier caliper. The difference between the maximum and minimum values was taken as the film thickness unevenness and judged according to the following criteria. "Evaluation Criteria" ○: Film thickness unevenness is less than 50 μm △: Film thickness unevenness is 50 μm or more and less than 100 μm ×: Film thickness unevenness is 100 μm or more

[0102] [Hue] A 3 cm square was cut out from the center of the body of the molded container, and the color was measured using a color difference meter (SpectroColorMeterSE2000, manufactured by Nippon Denshoku Industries Co., Ltd.) to measure the L* value and YI value. The hue when viewed from the outside was judged according to the following criteria. "Evaluation Criteria" (L* value) ○: 70.0 or more △: 60.0 or more and less than 70.0 ×: Less than 60.0 (YI value) ○: Less than 10.0 △: 10.0 or more and less than 15.0 ×: 15.0 or more

[0103] [Concealment] A 3 cm square was cut out from the center of the body of the molded container, and the total light transmittance was measured using a haze meter (Hazeguard Plus, manufactured by BYK) and evaluated according to the following criteria. "Evaluation Criteria" ○: Less than 1.0% △: 1.0% or more and less than 10.0% ×: 10.0% or more

[0104] [Drop strength] The molding container was filled with water, sealed, and dropped from a height of 1 m onto the concrete floor twice, once so that the bottom part touched the floor and once so that the body part touched the floor, and the results were evaluated according to the following criteria. "Evaluation Criteria" ○: No cracks or breaks were observed, and no leakage of the contents was observed. △: No leakage of contents was observed, but cracks or breaks occurred. ×: Cracks and breaks occurred, and leakage of contents was observed.

[0105] . [Recycled material content] The content (mass %) of recycled material in the recycled resin layer was calculated according to the following formula and evaluated according to the following criteria. Proportion of recycled material (mass%) = (mass of recycled material (g) / mass of recycled resin composition (g)) × 100 "Evaluation Criteria" ○: 50% by mass or more △: 10% by mass or more and less than 50% by mass ×: Less than 10% by mass

[0106] [Table 2-1]

[0107] [Table 2-2]

[0108] [Table 2-3]

[0109] [Table 2-4]

[0110] [Table 3]

[0111] [Table 4]

[0112] From the results in Tables 2 to 4, it was confirmed that the recycled resin composition of the present invention can provide molded containers that are excellent in moldability, color, and drop strength.

[0113] By using the recycled resin composition of the present invention, it is possible to provide a recycled resin composition that has excellent moldability, color, and drop strength even when using collected PET bottle caps without sorting or separating them, thereby expanding new applications for recycling PET bottle caps. Furthermore, when recycling was carried out using only white caps after sorting by color of the caps, the hue was at a practical level with conventional recycled compositions, but the moldability and drop strength were poor. However, it was confirmed that the moldability and drop strength were improved by using the recycled resin composition of the present invention. It was also confirmed that the recycled resin composition of the present invention can be suitably applied to molded containers such as bottles and tubes, whether the recycled resin layer has a single-layer structure or a multi-layer structure.

Claims

1. A recycled resin composition containing a recycled resin (X1) obtained by using a PET bottle cap, a resin (X2) other than the recycled resin (X1), and a white pigment (Y1), The recycled resin composition has a melt mass flow rate (MFR) of 0.1 to 5 g / 10 min at 190°C, the recycled resin (X1) contains polyethylene and polypropylene, and the ratio of the polyethylene content (parts by mass) to the polypropylene content (parts by mass) is 70:30 to 95:5; A recycled resin composition, wherein the white pigment (Y1) is titanium oxide that has been surface-treated with any one selected from the group consisting of aluminum oxide, silicon dioxide, and siloxane.

2. The recycled resin composition according to claim 1, wherein the recycled resin (X1) has a melt mass flow rate (MFR) at 190°C of 0.1 to 10 g / 10 min.

3. The recycled resin composition according to claim 1, further comprising at least one pigment (Y2) selected from the group consisting of monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, and quinacridone violet.

4. The recycled resin composition according to claim 1, wherein the content of the white pigment (Y1) is 0.5 to 25 mass% based on 100 mass% of the recycled resin composition.

5. A molded container produced using the recycled resin composition according to any one of claims 1 to 4.

6. A single-layer molded container produced using the recycled resin composition according to any one of claims 1 to 4.

7. The molded container according to claim 5, wherein the lightness (L* value) of at least a portion of the surface is 60.0 or more.

8. A bottle, which is the molded container according to claim 5.

9. A tube, which is the molded container according to claim 5.

10. A method for producing a molded container, comprising a step of molding the recycled resin composition according to any one of claims 1 to 4 by blow molding or extrusion molding.

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