JP7150293B2 - container - Google Patents

Description

The present invention relates to containers.

2. Description of the Related Art Conventionally, tube containers have been used as containers for liquid-type or cream-type medicines, quasi-drugs, cosmetics, and the like.
Such a tube container is manufactured by extrusion molding because it can be easily formed into a desired shape.

A propylene tube container is known as such an extruded tube container, but the container is hard and not suitable for practical use.

On the other hand, as a tube container, an ethylene tube container is also known (Patent Document 1).

Japanese Patent No. 5941459

Resin molded products are required to have stress cracking resistance (hereinafter also referred to as "strike resistance") because cracks occur in the initial stage and the cracks grow and lead to breakage.
However, conventional containers such as the tube container described in Patent Document 1 do not have sufficient flexibility and resistance to stroke for practical use.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a container that is excellent in flexibility and resistance to stroke.

As a result of intensive research conducted by the present inventors to solve the above problems, the present inventors have found that the above problems can be solved by a container containing a specific compound, and have completed the present invention.
A configuration example of the present invention is as follows.

[1] A low-density polyethylene (A) having a melt flow rate of 70 to 150 g/10 minutes measured under conditions of 190° C. and a load of 21.18 N according to JIS K 6922-1;
A low-density polyethylene (B) having a melt flow rate in the range of 0.5 to 5 g/10 minutes measured under conditions of 190° C. and a load of 21.18 N according to JIS K 7210;
A container containing an ethylene-based elastomer (C).

[2] The container according to [1], wherein the polyethylene (A) has a flexural modulus of 50 to 200 MPa as measured according to JIS K 6922-2.
[3] The container according to [1] or [2], wherein the polyethylene (B) has a tensile modulus of elasticity measured according to JIS K 7162 of 150 to 450 MPa.

[4] The container according to any one of [1] to [3], wherein the polyethylene (A) or polyethylene (B) is biomass-derived low-density polyethylene.

[5] Any one of [1] to [4], wherein the elastomer (C) has a melt flow rate of 5 to 70 g/10 minutes measured under conditions of 230° C. and 21.18 N load according to ASTM D1238. container described in .
[6] The container according to any one of [1] to [5], wherein the elastomer (C) has a density of 850 to 880 kg/m ³ as measured according to ASTM D1505.

[7] The content of the polyethylene (A) is 50 to 80% by weight with respect to the total of 100% by weight of the polyethylene (A), the polyethylene (B) and the elastomer (C) [1] to [6] The container according to any one of
[8] The content of the polyethylene (B) is 10 to 40% by weight with respect to the total 100% by weight of the polyethylene (A), the polyethylene (B) and the elastomer (C) [1] to [7] The container according to any one of
[9] [1] to [8], wherein the content of the elastomer (C) is 5 to 30% by weight with respect to a total of 100% by weight of the polyethylene (A), polyethylene (B) and elastomer (C); The container according to any one of

[10] The container according to any one of [1] to [9], wherein the container is an injection molded container.
[11] The container according to any one of [1] to [10], wherein the container is an injection-molded tube container.

[12] A tube container, wherein the container comprises a head portion consisting of a mouth portion and a shoulder portion, and a body portion connected to the shoulder portion,
The container according to any one of [1] to [11], which is an injection-molded tube container in which the head and body are integrally molded.

[13] The container according to [12], wherein the body has a thickness of 1.0 mm or less.

According to the present invention, it is possible to easily obtain a container excellent in flexibility and resistance to stroke.
In particular, according to the present invention, the thickness of the body is 1.0 mm or less and the length of the body is 10 cm or more, yet the flexibility and stroke resistance are excellent, and the injection moldability is excellent. It is possible to easily obtain an injection-molded tube container that is excellent in

FIG. 1 is a schematic diagram showing an example of a side view of a container (tube container) according to the present invention.

≪Container≫
The container according to the present invention (hereinafter also referred to as "this container") has a melt flow rate of 70 to 150 g/10 minutes measured under the conditions of 190 ° C. and 21.18 N load according to JIS K 6922-1. , Low-density polyethylene (A) (hereinafter also referred to as "component (A)". The same applies to other resins.) and melt flow rate measured under the conditions of 190 ° C. and 21.18 N load according to JIS K 7210 is in the range of 0.5 to 5 g/10 min, low density polyethylene (B), and an ethylene-based elastomer (C).
Thus, it is only by using two types of low-density polyethylene, high MFR and low MFR, and the ethylene-based elastomer (C) that a container exhibiting the above effects can be obtained.

In addition, the present container may be colored in a desired color using a coloring agent or the like depending on the application or from the viewpoint of designability. It becomes easy to color a desired color or the like (hereinafter also referred to as “color toning”) at the time of the coloring or the like.

Although the container is not particularly limited, it is preferably an injection-molded container formed by injection molding from the viewpoint that a container having a desired shape can be easily formed, and the effects of the present invention are more effective. It is more preferable to use an injection-molded tube container from the viewpoint that it can be exhibited in a long time.
As shown in FIG. 1, the injection-molded tube container is generally a tube container having a head portion composed of a shoulder portion 3 and a mouth portion 1, and a body portion 2 connected to the shoulder portion 3. As shown in FIG.

The thickness of the trunk portion may be appropriately selected depending on the desired application, but is preferably 1.0 mm or less, more preferably 1.0 mm or less, more preferably from the point of view of the significance of using the components (A) to (C). is 0.5 to 1.0 mm, more preferably 0.5 to 0.9 mm, particularly preferably 0.5 to 0.8 mm.
By using the components (A) to (C), particularly the component (A), an injection-molded tube container having such a thickness can be easily formed, and the body portion has such a thickness. Even so, it is possible to obtain an injection-molded tube container that is excellent in flexibility and resistance to stroke.

In addition, the length of the trunk portion may be appropriately selected depending on the desired application, but it is preferably 10 cm or more, more preferably 10 cm or more, more preferably from the point of view of the significance of using the components (A) to (C). 11 to 20 cm, particularly preferably 14 to 16 cm.
By using the components (A) to (C), particularly the component (A), an injection-molded tube container having such a length can be easily formed, and the body portion has such a length. Even so, it is possible to obtain an injection-molded tube container that is excellent in flexibility and resistance to stroke.

The use of this container is not particularly limited, but it can be used for the use, storage, transportation, etc. of liquid or cream-like pharmaceuticals, quasi-drugs, cosmetics, foods, materials for construction, civil engineering, agriculture, etc. More preferably, it is used for the use, storage, transportation, etc. of liquid foundations, creams, facial cleansing foams, and the like.

<Low density polyethylene (A)>
This container is characterized by containing low-density polyethylene (A) having a melt flow rate (190° C., 21.18 N) of 70 to 150 g/10 minutes measured according to JIS K 6922-1.
By using such a high-MFR low-density polyethylene (A), moldability, particularly injection moldability, is excellent, and although the thickness and length of the body are within the above range, flexibility and stroke resistance are excellent. Injection-molded tube containers are readily available.
The polyethylene (A) contained in the present container may be of one type alone, or may be of two or more types.

Said MFR of polyethylene (A) is preferably 100 to 150 g/10 min.
When the MFR is within the above range, a composition having excellent injection moldability can be obtained, which is preferable. Specifically, since the resin fillability is improved when creating an injection-molded container, a container of a desired shape can be formed more easily, and the options for molding conditions are increased. The load on the mold can be reduced.

The density of polyethylene (A) measured according to JIS K 6922-1 is preferably 0.91 to 0.94 g/cm ³ , more preferably 0.91 to 0.94 g/cm 3 from the viewpoint of obtaining a container with excellent flexibility. 91 to 0.93 g/cm ³ .

The flexural modulus of polyethylene (A) measured according to JIS K 6922-2 is preferably 50 to 200 MPa, more preferably 50 to 200 MPa, from the viewpoint that a container having excellent mechanical strength and excellent stroke resistance can be obtained. 150 MPa.

Polyethylene (A) is not particularly limited in terms of its molecular weight, melting point, etc., as long as it satisfies the above MFR conditions. The melting point (JIS K 6922-2) is preferably from 90 to 115°C, more preferably from 95 to 110°C, in order to obtain sufficient durability.

Polyethylene (A) may be synthesized by a conventionally known method, preferably by high-pressure radical polymerization, or a commercially available product may be used.

The high-pressure radical polymerization is not particularly limited, and includes a method of performing polymerization under high pressure using a radical generator such as peroxide or oxygen. The polymerization conditions are not particularly limited, but include, for example, a temperature of 200 to 300° C. and a pressure of 1,000 to 2,000 atm.
It should be noted that a copolymer may be prepared by using a small amount of vinyl acetate, ethylene acrylate, or the like together with ethylene at the time of synthesis. Also, the MFR can be adjusted by using a molecular weight modifier such as hydrogen or hydrocarbons such as methane and ethane.

Polyethylene (A) may be biomass-derived low-density polyethylene from the viewpoint of suppressing an increase in the amount of CO ₂ in the atmosphere and leading to saving of petroleum resources.

The biomass is not particularly limited, but sugar cane (including bagasse), corn, starch, castor oil, crushed tatami mats (used waste tatami mats), wood chips, wood flour, sawdust, paper scraps, plant sorghum, squeezed sugar beets. Plant matter such as dregs and rice straw, coniferous tree materials, hardwood materials, non-tree materials, wastes of these materials, and the like can be mentioned.

The biomass-derived low-density polyethylene in the present invention is not particularly limited as long as it is a low-density polyethylene obtained using biomass-derived ethylene as a raw material. Specifically, alcohol obtained by fermenting a plant is used as a raw material. plant-derived low-density polyethylene using ethylene synthesized as .
More specifically, by a conventionally known method, the sugar solution and starch obtained from the biomass are fermented with microorganisms such as yeast to produce bioethanol, which is then heated in the presence of a catalyst to cause an intramolecular dehydration reaction. Using ethylene obtained by Etc. and optionally α-olefins (e.g. 1-butene, 1-hexene) etc. as monomers, in the presence of a conventional catalyst ( (co) low-density polyethylene obtained by polymerization. As the copolymer, in addition to biomass-derived α-olefins, those using fossil fuel-derived comonomers generally used in the synthesis of low-density polyethylene may be used.

The content of polyethylene (A) with respect to the total of 100% by weight of the polyethylene (A), polyethylene (B) and elastomer (C) is such that a container having excellent flexibility, color toning property and resistance to stroke can be obtained. Therefore, the content is preferably 50 to 80% by weight, more preferably 60 to 75% by weight, particularly preferably 65 to 70% by weight, in view of better injection moldability.

<Low density polyethylene (B)>
This container is characterized by containing low-density polyethylene (B) having an MFR (190° C., 21.18 N) measured according to JIS K 7210 of 0.5 to 5 g/10 minutes.
By using such a low-MFR low-density polyethylene (B), it is possible to obtain a container having excellent flexibility and resistance to stroke.
The polyethylene (B) contained in the container may be of one type alone or two or more types.

The MFR of the polyethylene (B) is preferably 0.5 to 3 g/10 minutes from the viewpoint of obtaining a container having more excellent resistance to stroke.

The density of polyethylene (B) measured according to JIS K 7112 is preferably 0.91 to 0.94 g/cm ³ , more preferably 0.91, in order to obtain a container with particularly excellent flexibility. ˜0.93 g/cm ³ .

The tensile modulus of elasticity measured according to JIS K 7162 of the low-density polyethylene (B) is preferably 150 to 450 MPa, more preferably 150, from the viewpoint of obtaining a container having excellent mechanical strength and excellent stroke resistance. ~300 MPa, particularly preferably 150-250 MPa.

As polyethylene (B), a commercially available product may be used, or it may be obtained by synthesizing by a conventionally known method. As the conventionally known method, high-pressure low-density polyethylene using a so-called Ziegler-Natta catalyst or the like may be used, or metallocene low-density polyethylene using a metallocene catalyst or the like may be used.

The polyethylene (B) may be a low-density polyethylene obtained by polymerizing a mixed monomer containing ethylene as a main component and an α-olefin as a secondary component in the presence of a metallocene catalyst or the like. As the α-olefin, one or two or more α-olefins having 3 to 40 carbon atoms, preferably 4 to 35 carbon atoms, more preferably 4 to 30 carbon atoms are used. and an α-olefin having 10 to 26 carbon atoms can be used in combination. When the low-density polyethylene is a copolymer, the α-olefin content is preferably 3 to 15 mol% relative to the copolymer.

The polyethylene (B) may be biomass-derived low-density polyethylene from the viewpoint of suppressing an increase in the amount of CO ₂ in the atmosphere and leading to saving of petroleum resources.
The biomass-derived low-density polyethylene (B) may be synthesized by the method described above or the like, or may be a commercially available product.

The content of polyethylene (B) with respect to the total of 100% by weight of the polyethylene (A), polyethylene (B) and elastomer (C) is such that a container having excellent toning properties, flexibility and resistance to stroke can be obtained. Therefore, it is preferably 10 to 40% by weight, more preferably 15 to 40% by weight, still more preferably 15 to 30% by weight, and particularly preferably 20 to 40% by weight from the viewpoint of better injection moldability. 25% by weight.

<Ethylene elastomer (C)>
The present container is characterized by containing an ethylene-based elastomer (C).
By using such an elastomer (C), it is possible to easily obtain a container having excellent flexibility, color toning properties, and low-temperature sealing properties.
The elastomer (C) contained in the container may be of one type alone, or may be of two or more types.

The elastomer (C) is preferably an ethylene/α-olefin copolymer, more preferably an ethylene/α-olefin random copolymer. Examples of ethylene/α-olefin copolymers include copolymers of ethylene and one or more α-olefins having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms.
The α-olefin content in the copolymer is generally 3-39 mol %, preferably 5-30 mol %, more preferably 5-25 mol %, relative to the copolymer.

Specific examples of the α-olefins having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methylpentene-1, 1-octene, 1-decene and 1-dodecene. Among these, propylene, 1-butene, 1-hexene and 1-octene are preferred.

If necessary, other comonomers, dienes such as 1,6-hexadiene and 1,8-octadiene, and cyclic olefins such as cyclopentene may be used in small amounts.

Ethylene and α-olefins used in synthesizing the elastomer (C) suppress the increase in the amount of CO ₂ in the atmosphere and lead to the saving of petroleum resources. It is preferable to use biomass-derived ethylene or α-olefin from the viewpoint that a molded container can be easily obtained.

As the elastomer (C), it is preferable to use a resin that is compatible with polyethylenes (A) and (B) from the viewpoint that a container having excellent toning properties and resistance to stroke can be easily obtained.

The MFR (230° C., 21.18 N) of the elastomer (C) measured according to ASTM D 1238 is preferably 5 to 70 g/10 minutes, preferably more than 5 to 70 g/10 minutes, because a composition having excellent injection moldability can be obtained. It is more preferably 50 to 70 g/10 min from the viewpoint of obtaining a composition having excellent resistance, and more preferably 5 from the viewpoint of easily obtaining an injection-molded container having excellent resistance to stroke. ~10 g/10 min.

The density of the elastomer (C) measured according to ASTM D 1505 is preferably 850 to 880 kg/m ³ , more preferably 860 to 870 kg/m ³ in order to obtain a container having particularly excellent flexibility.

The elastomer (C) may be obtained by synthesizing by a conventionally known method using a vanadium-based catalyst, a titanium-based catalyst, a metallocene-based catalyst, or the like, or a commercially available product may be used.

The content of the elastomer (C) with respect to the total of 100% by weight of the polyethylene (A), polyethylene (B) and elastomer (C) is such that a container having excellent flexibility, resistance to stroke and color toning can be obtained. Therefore, the content is preferably 5 to 30% by weight, more preferably 5 to 20% by weight, and particularly preferably 10 to 15% by weight, from the viewpoint of better injection moldability.

<Other ingredients>
If necessary, the container may contain components other than the components (A) to (C) as long as they do not impair the effects of the present invention.

Other components include, for example, thermoplastic resins, antioxidants, heat stabilizers, light stabilizers, stabilizers such as weather stabilizers, ultraviolet scattering agents, anti-slip agents, anti-fogging agents, colorants, and dispersants. , fillers, antistatic agents, lubricants, softeners, plasticizers and processing aids.
The present container may contain each of these other components singly or in combination of two or more.

According to the present invention, a container having a certain degree of transparency can be obtained. Such a container is preferable from the viewpoint that the contents can be visually recognized.
Depending on the application and from the point of design, a colored container may be required. In this case, a conventionally known coloring agent may be used. The container, which does not contain a coloring agent, can allow the contents to be visually recognized, or can be easily colored to a desired color with a coloring agent.

<Container manufacturing method>
After mixing the components (A) to (C) and optionally the other components to form the composition, or while the composition is being formed, the container is processed by a conventionally known method, particularly It is preferably manufactured by injection molding.

The method for forming the composition is not particularly limited, but each of the components is melted using a conventionally known device, specifically, a single screw extruder, a twin screw extruder, a kneader, a mixer, a two-roll mill, or the like. A kneading method is preferred.

The MFR measured based on JIS K 7210 (190° C., 21.18 N load) of the composition makes the composition excellent in moldability, particularly injection moldability, and makes a container excellent in mechanical strength such as impact resistance. From the viewpoint of obtaining, it is preferably 15 to 80 g/10 minutes, more preferably 30 to 60 g/10 minutes, and particularly preferably 30 to 40 g/10 minutes.

This container is preferably an injection-molded tube container in which the head portion and the body portion are integrally formed in order to exhibit the effects of the present invention more effectively. In the present invention, since the components (A) to (C) are used as the raw materials, the injection moldability is particularly excellent, and the tube container can be produced by integral molding.
By integrally molding, the step of combining the head and the body can be omitted, and complicated and complicated steps are not required, and the cost can be reduced. It is preferable because deterioration of quality such as deterioration of welding strength between the body and the body is unlikely to occur.

Specifically, such an integrally molded injection-molded tube container can be manufactured by the following method.
Specifically, an integrally molded injection-molded tube container can be obtained by injecting the composition using an injection mold capable of integrally forming a mouth portion, a shoulder portion, and a body portion.

During the injection, the composition is preferably injected into the cavity through at least two gates. By using two or more sprues, the composition can be injected with a uniform pressure, so that a tube container having a desired shape can be easily obtained.

The integrally molded body of the head and body thus obtained can be made into a tube container by welding the end of the body on the side opposite to the head side.
As the welding method, conventionally known welding methods such as hot air welding, ultrasonic welding, and heat sealing can be employed without limitation.

In addition, if necessary, the container may be embossed for the purpose of improving the design, etc., which enables small-lot production, does not require a printing plate, and can accommodate a variety of designs. Digital printing may be done from points.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these.

In the following tests, commercial products having the following physical properties were used.
LDPE1: Density (JIS K 6922-1); 915 kg/m ³ , MFR (JIS K 6922-1, 190°C, 21.18 N); 145 g/10 min, Flexural modulus (JIS K 6922-2); 90 MPa
LDPE2: Density (JIS K 7112); 919 kg/m ³ , MFR (JIS K 7210, 190°C, 21.18 N); 0.7 g/10 min, Tensile modulus (JIS K 7162); 215 MPa
LLDPE: density (JIS K 6922-1); 928 kg/m ³ , MFR (JIS K 6922-1, 190°C, 21.18 N); 60 g/10 min, flexural modulus (JIS K 6922-2); 300 MPa
Ethylene elastomer 1: MFR (ASTM D1238, 230°C, 21.18N); 65 g/10 min, density (ASTM D1505); 870 kg/m ³
Ethylene-based elastomer 2: MFR (ASTM D1238, 230°C, 21.18N); 6.7 g/10 min, density (ASTM D1505); 864 kg/m ³

[Examples 1 to 12 and Comparative Examples 1 to 5]
The raw material shown in Table 1 is put into an injection molding machine in the amount shown in Table 1, and injection molding is performed at 200 ° C. using an injection molding mold that can integrally form the mouth, shoulder and body. An injection-molded tube container in which the head portion and the trunk portion were integrally formed was obtained by welding the end opposite to the head portion at 350°C.
The tube container thus obtained had a trunk portion with a thickness of 0.7 mm and a length of 14.5 cm.

<MFR>
Using the raw materials (compositions) shown in Table 1, MFR was measured under conditions of 190° C. and a load of 21.18 N based on JIS K 7210. Table 1 shows the results.

<Filling pressure>
When forming the injection-molded tube container, the resin filling pressure (in-cylinder resin pressure) required to fill the mold in about 0.6 seconds was measured using a pressure sensor in the injection molding machine. Table 1 shows the results.

<Toning property>
The upper portion (portion close to the mouth portion), the central portion and the lower portion of the body portion of the injection-molded tube container obtained were each cut out to 1 cm×5 cm, and 5 specimens were prepared for each portion. Using the cut specimen, the haze was measured with a spectrophotometer (V-650 (manufactured by JASCO Corporation) and the average haze value was calculated. Based on the obtained average haze value, the following evaluation criteria were applied. The results are shown in Table 1. The results are shown in Table 1.
(Evaluation criteria)
◎: Average haze value is 0% or more and less than 50% △: Average haze value is 50% or more and less than 70% ×: Average haze value is 70% or more

<Flexibility>
Using the obtained injection-molded tube container, a squeeze test was conducted by 10 subjects unrelated to the present invention.
Specifically, 10 subjects were asked to judge whether or not it was easy to crush the injection-molded tube container when it was crushed so as to push out the contents.
When the tube containers obtained in Examples 1 to 12 and Comparative Examples 1 to 5 were used, all 10 subjects felt that they were easy to crush (also evaluated as "fair").

<Stress cracking resistance>
200 ml of a 1% benzalkonium chloride aqueous solution was placed in the tube obtained in Examples and Comparative Examples, capped, and then placed in a constant temperature bath (40°C, 90% RH) for 2 weeks with the cap up. After that, the tube was taken out from the constant temperature bath, and cracks in the tube were visually checked by hand. Ten tubes were tested and evaluated based on the following evaluation criteria. Table 1 shows the results.
S: No cracks were observed in any of the 10 tubes.
A: Cracks were confirmed in one or two tubes.
B: Cracks were confirmed in 3 to 5 tubes.
C: Cracks were confirmed in 6 to 9 tubes.
D: All 10 tubes were broken.

1: Mouth 2: Body 3: Shoulder

Claims (11)

A low-density polyethylene (A) having a melt flow rate of 70 to 150 g/10 minutes measured under conditions of 190° C. and a load of 21.18 N according to JIS K 6922-1;
A low-density polyethylene (B) having a melt flow rate in the range of 0.5 to 5 g/10 minutes measured under conditions of 190° C. and a load of 21.18 N according to JIS K 7210;
A container formed from a composition containing an ethylene elastomer (C),
The MFR of the composition measured based on JIS K 7210 (190° C., 21.18 N load) is 15 to 80 g/10 minutes,
The container is a tube container comprising a head portion composed of a mouth portion and a shoulder portion, and a body portion connected to the shoulder portion, wherein the thickness of the body portion is 1.0 mm or less .
container. 2. The container according to claim 1, wherein said polyethylene (A) has a flexural modulus of 50 to 200 MPa as measured according to JIS K 6922-2. 3. The container according to claim 1, wherein the polyethylene (B) has a tensile modulus of elasticity measured according to JIS K 7162 of 150 to 450 MPa. The container according to any one of claims 1 to 3, wherein said polyethylene (A) or polyethylene (B) is a biomass-derived low-density polyethylene. 5. The melt flow rate according to ASTM D 1238 of the elastomer (C) measured under conditions of 230° C. and 21.18 N load is 5 to 70 g/10 min, according to any one of claims 1 to 4. container. A container according to any preceding claim, wherein the elastomer (C) has a density measured according to ASTM D 1505 of 850-880 kg/m ³ . 7. Any one of claims 1 to 6, wherein the content of said polyethylene (A) is 50 to 80% by weight with respect to a total of 100% by weight of said polyethylene (A), polyethylene (B) and elastomer (C). container described in . 8. The content of said polyethylene (B) is 10 to 40% by weight with respect to a total of 100% by weight of said polyethylene (A), polyethylene (B) and elastomer (C), any one of claims 1 to 7. container described in . 9. Any one of claims 1 to 8, wherein the content of said elastomer (C) is 5 to 30% by weight with respect to a total of 100% by weight of said polyethylene (A), polyethylene (B) and elastomer (C). container described in . A container according to any preceding claim, wherein the container is an injection molded tube container. The container is a tube container comprising a head portion consisting of a mouth portion and a shoulder portion, and a body portion connected to the shoulder portion,
The container according to any one of claims 1 to 10 , which is an injection-molded tube container in which the head and body are integrally molded.

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