JP5373569B2 - Film cutter - Google Patents

Abstract

Provided is a film cutter using a lactic acid-based resin as a material, wherein the film cutter has excellent cutting properties, can be easily attached to a paper storage container, and can provide a sufficient adhesion strength. The film cutter is formed of a laminate composed of a layer (I) which contains 70 parts by mass to 100 parts by mass of a lactic acid resin (A-1) having a quantity of heat of crystal fusion (?Hm) not less than 30J/g, and 0 parts by mass to 30 parts by mass of inorganic fine particles (B), and a layer (II) which is formed on at least one surface of the layer (I) and which contains 51 parts by mass to 95 parts by mass of a lactic acid resin (A-2) having a quantity of heat of crystal fusion (?Hm) between 0 J/g and 25 J/g, and 5 parts by mass to 49 parts by mass of an ethylene copolymer (C). The laminate is stretched in at least one direction.

Description

  The present invention relates to a plastic film cutter that is excellent in adhesion to a paper material of a storage box that stores a wrap film or the like, and that has a cutting property equivalent to that of a metal blade.

Thin film such as wrap film, aluminum foil, and cooking sheet is stored in a paper storage box (carton) in a state of being wound around a paper tube, and the necessary length is pulled out from the storage box when necessary. Used by cutting with a sawtooth film cutter.
Many of these conventional film cutters are made of metal, and are attached by crimping to the edge of the front plate, bottom plate, lid plate or the like of the storage box.
However, the metal cutter is excellent in cutability, but it remains unburned if it is incinerated at the time of disposal. Therefore, it has been necessary to remove it from the storage box and discard it.

  From such a point of view, paper cutters and plastic cutters, particularly biodegradable plastic cutters have been proposed instead of metal cutters.

  Paper cutters can be broadly divided into so-called “resin-cured paper blades” that are made of paperboard and coated with thermosetting resin, or impregnated and cured, and raw paper made of cellulose fibers. Using a vulcanization effect, after forming and stacking to a certain layer thickness, using a vulcanized fiber obtained by extracting and removing zinc chloride and drying and molding it, a moisture-proof coating is formed on it and punched into a sawtooth shape There are two types of cutters, so-called “VF blades”.

  As a method for adhering the paper cutter and the storage box, there are usually a method of adhering by applying an adhesive to the storage box and the cutter and an adhesive method using an ultrasonic welding method (Patent Document 1). Although these paper cutters solve the problems of the metal cutters pointed out above, it cannot be denied that the paper cutters are inferior in cutting performance and cutting durability compared to metal cutters. This problem is particularly noticeable in polyethylene and polyvinyl chloride wrap films having a relatively large film elongation.

  On the other hand, as a cutter made of biodegradable plastic, for example, a film cutter mainly composed of a polylactic acid resin, which is a resin derived from a plant such as corn, has been proposed (Patent Documents 2 and 3). Since the starting material is derived from plants, it is possible to save exhaustive resources.

  However, such a film cutter mainly composed of a polylactic acid-based resin has almost the same cutting performance and cutting durability as a metal cutter, but has a problem of fixing strength when attached to the paper material of the storage box. It was. That is, if the material is fixed by a caulking method like a metal cutter, the material is difficult to be plastically deformed, so that the material is not sufficiently fixed. In addition, the fixing strength is insufficient when the fixing is performed by an ultrasonic welding method like a paper cutter. For this reason, there is a problem that a method of applying with an adhesive and a step of bonding with an adhesive are required, resulting in an increase in manufacturing cost.

  Then, as a means for solving such a subject, the film cutter (patent document 4) which consists of lactic acid-type resin which has the D body amount of a specific ratio is proposed. However, according to the present technology, although the weldability with paper is relatively good, it takes a long time to firmly bond with paper, so that it is not easy to mass-produce industrially.

JP 07-52255 A JP-A-11-99498 Japanese Patent Application Laid-Open No. 2005-212064 JP 2006-263892 A

  As described above, the lactic acid-based resin film cutter that has been conventionally disclosed has excellent cutting properties (also referred to as cutting properties) and cutting durability, but can obtain sufficient fixing strength with a paper storage box. It was difficult and it was difficult to industrially attach the film cutter to the storage box.

  Therefore, the present invention provides a new film cutter that uses a lactic acid resin as a material, and can be easily attached to a paper storage box as well as excellent cutting properties, and can obtain a sufficient fixing strength. A film cutter is to be provided.

  The present invention contains a lactic acid resin (A-1) having a crystal melting heat ΔHm of 30 J / g or more in a proportion of 70 parts by mass or more and 100 parts by mass or less, and 0 mass of inorganic fine particles (B). 51 parts by mass of a lactic acid resin (A-2) having a heat of crystal fusion ΔHm of 0 J / g or more and 25 J / g or less on at least one side of the layer (I) containing at least 30 parts by mass and 30 parts by mass or less As mentioned above, it is formed from a laminate having a layer (II) containing 95 parts by mass or less and containing ethylene copolymer (C) in a proportion of 5 parts by mass or more and 49 parts by mass or less. A film cutter is proposed, which is a film cutter, wherein the laminate is stretched in at least one direction.

The present invention optimizes the crystallinity of the lactic acid-based resin for each layer (I) (II), and further blends a predetermined amount of the ethylene-based copolymer into the layer (II) having a role as a fixing layer. It has the same cutability as a metal cutter, has excellent weldability with a paper material, and can easily attach a film cutter to a storage box.
Further, a layer (I) mainly composed of a predetermined lactic acid resin (A-1) and a layer (II) mainly composed of a predetermined lactic acid resin (A-2) and an ethylene copolymer (C). ), The laminate can be manufactured by coextrusion.
According to the film cutter of the present invention, for example, the layer (II) is disposed so as to overlap the paper surface of the storage box, and is adhered to the paper surface of the storage box by ultrasonic welding, thereby forming a storage box with a film cutter. it can.

It is a top view of the film cutter produced by the cutability evaluation test.

  Hereinafter, an example of an embodiment of the present invention will be described, but the scope of the present invention is not limited to the embodiment described below.

<Laminated structure>
The laminate according to this embodiment (hereinafter referred to as “the present laminate”) is a laminate used to form a film cutter, and includes a layer (I) containing a predetermined lactic acid resin (A-1), A layered product comprising a layer (II) containing a predetermined lactic acid resin (A-2) and an ethylene copolymer (C).

In the present laminate, it is only necessary to have the layer (II) on at least one side of the layer (I), for example, it may have the layer (II) on both sides of the layer (I), Even if the layer (II) is provided on one side of the layer (I) and an arbitrary layer is provided on the opposite side of the layer (II), no practical problem is caused.
Further, another layer may be interposed between the layer (I) and the layer (II).

The thickness of the layer (I) is preferably 180 μm or more and 400 μm or less, more preferably 200 μm or more and 380 μm or less, and further preferably 220 μm or more and 350 μm or less.
On the other hand, the thickness of the layer (II) is preferably 3 μm or more and 100 μm or less, more preferably 5 μm or more and 80 μm or less, and further preferably 10 μm or more and 50 μm or less.
By using the laminate having the layer (I) and the layer (II) within such a range, a film cutter having excellent rigidity, mechanical properties, cutability and heat resistance can be provided.

<Layer (I)>
The layer (I) is a layer that serves as a base material in the laminate, and includes a predetermined lactic acid resin (A-1), inorganic fine particles (B) as necessary, and ethylene as necessary. It is a layer containing a copolymer (C).

(Lactic acid resin (A-1))
Examples of the lactic acid resin (A-1) include poly (L lactic acid) whose structural unit is L lactic acid, poly (D lactic acid) whose structural unit is D lactic acid, and poly (DL) whose structural units are L lactic acid and D lactic acid. Lactic acid) or a mixed resin thereof can be used. Moreover, the copolymer of these, (alpha) -hydroxycarboxylic acid, and diol / dicarboxylic acid can also be used.

By optimizing the ratio (molar ratio) of L-lactic acid (L-form) and D-lactic acid (D-form) in the lactic acid resin (A-1), the crystal melting heat quantity ΔHm optimum for the layer (I) is adjusted. It is preferable to do this. That is, by optimizing the ratio (molar ratio) between L-lactic acid (L-form) and D-lactic acid (D-form), the heat of crystal fusion ΔHm of the lactic acid resin (A-1) becomes 30 J / g or more. It is preferable to adjust as follows.
If ΔHm of the lactic acid-based resin (A-1) is 30 J / g or more, the strength of the layer (I) serving as the base material of the film cutter can be sufficiently maintained, and the cut property can be sufficiently enhanced. .
From this point of view, the heat of crystal fusion ΔHm of the lactic acid resin (A-1) is more preferably adjusted to 35 J / g or more, and more preferably 40 J / g or more.
The upper limit of the lactic acid-based resin (A-1) is not particularly required. The higher the ΔHm, the higher the strength, and the performance as a film cutter, that is, a plastic blade can be sufficiently exhibited.

  For example, L-form / D-form = 100/0 to 97/3, or L-form / D-form = 0/100 to 3/97 lactic acid resin (A-1-1) and L-form / D-form = A lactic acid resin (A-1-2) of 97/3 to 85/15 or 3/97 to 15/85 is mixed at a mass ratio of 100/0 to 50/50 to obtain a lactic acid resin ( It is preferable to adjust the heat of crystal fusion ΔHm of A-1) to be 30 J / g or more. In particular, mixing at a ratio of 100/0 to 90/10 is more preferable, and mixing at a ratio of 100/0 to 95/5 is more preferable.

Further, the lactic acid resin (A-1) may be a copolymer with α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid as described above.
In this case, as the “α-hydroxycarboxylic acid” copolymerized with the lactic acid-based resin, optical isomers of lactic acid (D-lactic acid for L-lactic acid, L-lactic acid for D-lactic acid), Glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyn-butyric acid, 2-hydroxy3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, 2-hydroxycaproic acid, etc. Examples of the “aliphatic diol” that is copolymerized with a lactic acid resin include ethylene glycol, 1,4-butanediol, 1 and lactones such as bifunctional aliphatic hydroxy-carboxylic acid, caprolactone, butyrolactone, and valerolactone. , 4-cyclohexanedimethanol and the like, and “aliphatic dicarboxylic acid” includes succinic acid, adipic acid, suberic acid, sebacic acid and dodeic acid. Down two acid and the like.

As a polymerization method for the lactic acid-based resin, a condensation polymerization method, a ring-opening polymerization method, and other known polymerization methods can be employed. For example, in the condensation polymerization method, L-lactic acid or D-lactic acid, or a mixture thereof can be directly dehydrated and condensation polymerized to obtain a lactic acid resin having an arbitrary composition.
Further, in the ring-opening polymerization method, a polylactic acid-based polymer can be obtained using lactide, which is a cyclic dimer of lactic acid, using a selected catalyst while using a polymerization regulator or the like as necessary. At this time, L-lactide which is a dimer of L-lactic acid, D-lactide which is a dimer of D-lactic acid, or DL-lactide composed of L-lactic acid and D-lactic acid is used as the lactide. A lactic acid resin having any desired composition and crystallinity can be obtained by mixing and polymerizing these as necessary.

As necessary, such as further improving the heat resistance, terephthalic acid can be used as a small amount copolymerization component within a range not impairing the essential properties of the lactic acid resin, that is, within a range containing 90% by mass or more of the lactic acid resin component. Non-aliphatic diols such as non-aliphatic dicarboxylic acids and ethylene oxide adducts of bisphenol A may be added.
Furthermore, a small amount of a chain extender such as a diisocyanate compound, an epoxy compound, or an acid anhydride may be added for the purpose of increasing the molecular weight.

  The weight average molecular weight of the lactic acid resin (A-1) is preferably 50,000 or more and 400,000 or less, more preferably 100,000 or more and 250,000 or less. If it is at least the lower limit of this range, preferable practical physical properties can be obtained, and if it is not more than the upper limit value, the melt viscosity will not be too high, and good moldability can be obtained.

(Inorganic fine particles (B))
The layer (I) of the laminate is preferably blended with inorganic fine particles (B) as necessary for the purpose of enhancing the visibility when using a film cutter and ensuring safety.

Inorganic fine particles (B) include talc, kaolin, calcium carbonate, bentonite, mica, sericite, glass flakes, magnesium hydroxide, aluminum hydroxide, antimony trioxide, barium sulfate, titanium oxide, lead titanate, potassium titanate , Zircon oxide, zinc sulfide, antimony oxide, zinc oxide, zinc borate, hydrous calcium borate, alumina, magnesia, wollastonite, zonotlite, sepiolite, whisker, glass fiber, glass flake, metal powder, beads, silica balloon, A shirasu balloon can be mentioned. Any of these can be used alone or in combination of two or more.
Among these, in particular, by using a material having a refractive index of 1.6 or more, concealability can be efficiently imparted with a lower addition amount, and excellent visibility can be obtained.
Specific examples of inorganic fine particles having a refractive index of 1.6 or more, particularly 2.0 or more include barium sulfate, magnesium oxide, zinc oxide, zinc sulfide, zircon oxide, potassium titanate, lead titanate, and titanium oxide. Can be mentioned.
It is particularly preferable to blend titanium oxide having the highest refractive index.

The average particle size of the inorganic fine particles is preferably 0.1 μm to 5 μm, more preferably 1 μm to 3 μm. If the average particle size is 5 μm or less, the inorganic fine particles are unlikely to be the starting point of destruction, so that the strength and elongation of the film cutter can be maintained. On the other hand, if the average particle size is 0.1 μm or more, the inorganic fine particles aggregate. Therefore, it is preferable that poor dispersion hardly occur.
In addition, the average particle diameter in this invention shows the value of D50 measured by a laser diffraction method.

(Ethylene copolymer (C))
The layer (I) of this laminate can be blended with an ethylene copolymer (C) as necessary for the purpose of further preventing delamination from the layer (II).
At this time, the ethylene copolymer (C) is the same as the ethylene copolymer (C) of the layer (II) described later.
Therefore, for example, trimming loss that occurs when both ends of the laminate are cut and trimmed can be blended with the raw material of the layer (I), so that waste of material can be eliminated and material cost can be reduced.

(Content ratio in layer (I))
The content ratio of the lactic acid resin (A-1) in the layer (I) is 70 parts by mass or more and 100 parts by mass with respect to 100 parts by mass of the total content of the lactic acid resin (A-1) and the inorganic fine particles (B). The amount is preferably 80 parts by mass or more and 100 parts by mass or less, more preferably 90 parts by mass or more and 100 parts by mass or less.
If the content ratio of (A-1) is 70 parts by mass or more, the rigidity and heat resistance of the lactic acid resin can be maintained, and the performance as a film cutter can be sufficiently exhibited.

Further, since the inorganic fine particles (B) are optional components, they may be 0 parts by mass, that is, they may not be contained, and the content ratio of the inorganic fine particles (B) is the lactic acid resin (A-1) and the inorganic fine particles (B). The total content of 100 parts by mass is preferably 0 parts by mass or more and 30 parts by mass or less, particularly preferably 0.1 parts by mass or more and 20 parts by mass or less, and more preferably 0.5 parts by mass. As mentioned above, it is more preferable that it is 15 mass parts or less, and it is still more preferable that it is 1 mass part or more and 10 mass parts or less among them.
When the inorganic fine particles (B) are contained, if the content is 0.1 parts by mass or more, the concealability of the film cutter is sufficient, and the visibility at the time of use is sufficient, and the handling safety can be improved. On the other hand, if it is 30 parts by mass or less, it is possible to suppress the occurrence of voids at the interface between the resin and the inorganic fine particles in the stretching process at the time of manufacturing the film cutter, the rigidity of the film cutter is reduced, and the cutting properties of various films Can be prevented from being damaged.

  In addition, since the ethylene copolymer (C) is an optional component in the layer (I), it may not be contained in 0 parts by mass, that is, when the ethylene copolymer (C) is contained, 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the total content of the lactic acid resin (A-1), the inorganic fine particles (B) and the ethylene copolymer (C) in the layer (I). In particular, it is preferably 1 to 10 parts by mass, more preferably 3 to 10 parts by mass, and more preferably 5 to 10 parts by mass. It is particularly preferable that the amount is not more than part by mass.

  The layer (I) is blended with additives such as an ultraviolet absorber, a light stabilizer, an antioxidant, a plasticizer, a nucleating agent, a lubricant, a pigment, and a dye as long as the effects of the present invention are not impaired. Can do.

<Layer (II)>
The layer (II) is a layer that serves as a fixing layer, for example, an ultrasonic welding layer, in the present laminate, and a layer containing a predetermined lactic acid resin (A-2) and an ethylene copolymer (C). It is.

(Lactic acid resin (A-2))
Examples of the lactic acid resin (A-2) include poly (L lactic acid) whose structural unit is L lactic acid, poly (D lactic acid) whose structural unit is D lactic acid, and poly (DL) whose structural units are L lactic acid and D lactic acid. Lactic acid) or a mixed resin thereof can be used. Furthermore, a copolymer of these with α-hydroxycarboxylic acid or diol / dicarboxylic acid may be used.

By optimizing the ratio (molar ratio) of L-lactic acid (L-form) and D-lactic acid (D-form) in the lactic acid resin (A-2), it is adjusted to the optimum amount of crystal melting heat ΔHm for the layer (II). It is preferable to do this. That is, by optimizing the ratio (molar ratio) between L-lactic acid (L-form) and D-lactic acid (D-form), the heat of crystal fusion ΔHm of the lactic acid resin (A-2) is 0 J / g or more, 25 J It is preferable to adjust so that it becomes below / g.
If the heat of crystal fusion ΔHm of the lactic acid resin (A-2) is 0 J / g or more, the heat resistance of the layer (II) can be maintained, and the plastic blades can be melted during production, transportation, storage or use. While the adhesion (blocking) can be suppressed, the crystallinity of the layer (II) is not too high if the heat of crystal fusion ΔHm of the lactic acid resin (A-2) is 25 J / g or less. Can be increased sufficiently.
From this point of view, the heat of crystal fusion ΔHm of the lactic acid resin (A-2) is particularly preferably 5 J / g or more, more preferably 7 J / g or more, and particularly preferably 10 J / g or more, and in particular, 23 J / g. / G or less, more preferably 20 J / g or less.

  More specifically, L-form / D-form = 100/0 to 97/3, or L-form / D-form = 0/100 to 3/97 lactic acid resin (A-1-1) and L-form / D body = 97/3 to 85/15, or 3/97 to 15/85 lactic acid resin (A-1-2), and lactic acid resin (A-1-1) and lactic acid resin The mass ratio with the resin (A-1-2) is preferably 0/100 to 40/60, more preferably 0/100 to 20/80, and more preferably 0/100 to More preferably, the ratio is 10/90. If the ratio of lactic acid-type resin (A-1-2) is 60 mass% or more, the crystallinity of layer (II) will not be too high and ultrasonic weldability can fully be improved.

Further, it may be a copolymer with α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid.
In this case, as the “α-hydroxycarboxylic acid” copolymerized with the lactic acid-based resin, optical isomers of lactic acid (D-lactic acid for L-lactic acid, L-lactic acid for D-lactic acid), Glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyn-butyric acid, 2-hydroxy3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, 2-hydroxycaproic acid, etc. Examples of the “aliphatic diol” that is copolymerized with a lactic acid resin include ethylene glycol, 1,4-butanediol, 1 and lactones such as bifunctional aliphatic hydroxy-carboxylic acid, caprolactone, butyrolactone, and valerolactone. , 4-cyclohexanedimethanol and the like, and “aliphatic dicarboxylic acid” includes succinic acid, adipic acid, suberic acid, sebacic acid and dodeic acid. Down two acid and the like.

As a polymerization method for the lactic acid-based resin, a condensation polymerization method, a ring-opening polymerization method, and other known polymerization methods can be employed. For example, in the condensation polymerization method, L-lactic acid or D-lactic acid, or a mixture thereof can be directly dehydrated and condensation polymerized to obtain a lactic acid resin having an arbitrary composition.
Further, in the ring-opening polymerization method, a polylactic acid-based polymer can be obtained using lactide, which is a cyclic dimer of lactic acid, using a selected catalyst while using a polymerization regulator or the like as necessary. At this time, L-lactide which is a dimer of L-lactic acid, D-lactide which is a dimer of D-lactic acid, or DL-lactide composed of L-lactic acid and D-lactic acid is used as the lactide. A lactic acid resin having any desired composition and crystallinity can be obtained by mixing and polymerizing these as necessary.

As necessary, such as further improving the heat resistance, terephthalic acid can be used as a small amount copolymerization component within a range not impairing the essential properties of the lactic acid resin, that is, within a range containing 90% by mass or more of the lactic acid resin component. Non-aliphatic diols such as non-aliphatic dicarboxylic acids and ethylene oxide adducts of bisphenol A may be added.
Furthermore, a small amount of a chain extender such as a diisocyanate compound, an epoxy compound, or an acid anhydride may be added for the purpose of increasing the molecular weight.

  A preferable range of the weight average molecular weight of the lactic acid resin (A-2) is 50,000 or more and 400,000 or less, preferably 100,000 or more and 250,000 or less. When it is below this range, practical properties are hardly expressed, and when it is above this range, the melt viscosity is too high and the molding processability is poor.

(Ethylene copolymer (C))
The ethylene-based copolymer (C) may be any copolymer having ethylene as a copolymerization component. For example, ethylene, vinyl acetate, acrylic acid, (meth) acrylic acid, ethyl (meth) acrylate, methyl ( Examples thereof include a copolymer with at least one selected from the group consisting of (meth) acrylic acid, maleic anhydride, and glycidyl (meth) acrylate.
Among them, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid ethyl copolymer, ethylene / vinyl acetate / maleic anhydride copolymer Polymer, ethylene / ethyl acrylate / maleic anhydride copolymer, ethylene / (meth) acrylic acid glycidyl copolymer, ethylene / vinyl acetate / (meth) acrylic acid glycidyl copolymer, ethylene / methyl (meth) acrylic An acid / (meth) acrylic acid glycidyl copolymer can be exemplified.

The crystal melting temperature Tm of the ethylene copolymer (C) is preferably 40 ° C. or higher and 90 ° C. or lower, more preferably 45 ° C. or higher and 85 ° C. or lower, and 50 ° C. or higher and 80 ° C. or lower. More preferably.
Further, the heat of crystal fusion ΔHm of the ethylene copolymer (C) is preferably 1 J / g or more and 100 J / g or less, more preferably 5 J / g or more and 90 J / g or less, and more preferably 10 J / g. More preferably, it is not less than g and not more than 80 J / g.
If the Tm and ΔHm are above the lower limits of the range, the crystallinity of the ethylene copolymer is not too low, the handling can be maintained well, and the sticking to the heating roll can be eliminated during production. . On the other hand, if Tm and ΔHm are equal to or less than the upper limit of the range, the crystallinity of the ethylene copolymer is not too high, and the ultrasonic weldability can be sufficiently improved.

The total content of comonomers copolymerized with ethylene in the ethylene-based copolymer (C) is preferably 10% by mass or more and 50% by mass or less, and 15% by mass or more and 45% by mass or less. More preferably, it is 20% by mass or more and 40% by mass or less.
At this time, if the total content of the comonomer is 10% by mass or more, the compatibility with the lactic acid resin is good and not causing poor appearance, and the layers (I) and (II) There is no delamination between them. On the other hand, if it is 50 mass% or less, it can suppress that the crystallinity of an ethylene-type copolymer falls, it can handle favorable and can prevent the adhesion | attachment to a heating roll, etc. at the time of production. .

Among the ethylene copolymers (C), by using an ethylene / vinyl acetate copolymer and an ethylene / methyl methacrylate copolymer, the ultrasonic weldability is particularly excellent, and the appearance and handling are also improved. It is also possible to provide a film cutter that does not cause any problems.
The content of vinyl acetate in the ethylene / vinyl acetate copolymer is preferably 15% by mass or more and 45% by mass or less, more preferably 20% by mass or more and 40% by mass or less, and 25% by mass. The content is more preferably 40% by mass or less.
In addition, the content of methyl methacrylate in the ethylene / methyl methacrylate copolymer is preferably 10% by mass or more and 30% by mass or less, more preferably 15% by mass or more and 25% by mass or less, More preferably, it is 15 mass% or more and 20 mass% or less.

(Content ratio in layer (II))
The content ratio of the lactic acid resin (A-2) in the layer (II) is 51 parts by mass or more with respect to 100 parts by mass of the total content of the lactic acid resin (A-2) and the ethylene copolymer (C). 95 parts by mass or less, particularly 55 parts by mass or more and 90 parts by mass or less, more preferably 60 parts by mass or more and 80 parts by mass or less.
On the other hand, the content ratio of the ethylene copolymer (C) is 5 parts by mass or more and 49 parts by mass with respect to 100 parts by mass of the total content of the lactic acid resin (A-2) and the ethylene copolymer (C). The amount is preferably 10 parts by mass or more and 45 parts by mass or less, more preferably 20 parts by mass or more and 40 parts by mass or less.
When the ratio of the ethylene copolymer is below this range, sufficient ultrasonic welding strength is not obtained. When the ratio is above this range, the ethylene copolymer is a matrix resin (sea-island structure in the layer (II)). Therefore, cohesive failure occurs when stress is applied to the paper and the film cutter after ultrasonic welding, and sufficient ultrasonic weldability with the paper cannot be obtained.

  The layer (II) should contain additives such as an ultraviolet absorber, a light stabilizer, an antioxidant, a plasticizer, a nucleating agent, a lubricant, a pigment, and a dye as long as the effects of the present invention are not impaired. Can do.

<This laminate>
It is important that the laminate is stretched in at least one direction. By stretching in at least one direction, a film cutter excellent in rigidity, mechanical properties, film cutability, and heat resistance can be formed.
The stretch ratio of the laminate is preferably 2 times or more and 16 times or less, more preferably 3 times or more and 12 times or less, and more preferably 4 times or more and 9 times or less in terms of area magnification. preferable. By stretching in such a range, it is possible to provide a film cutter having excellent rigidity, mechanical properties, film cutability, and heat resistance. In addition, more excellent heat resistance and mechanical properties can be imparted by performing heat treatment (heat setting) in the range of 100 ° C. or higher and 150 ° C. or lower after stretching.

Density of the laminate, 1.19 g / cm ³ or more, preferably at 1.51 g / cm ³ or less, in particular 1.20 g / cm ³ or more, 1.48 g / cm ³ or less, among others 1.21g / Cm ³ or more and 1.41 g / cm ³ or less is preferable.
If the density of this laminated body is in the said range, the rigidity of a film cutter can be maintained and cut property can also be maintained. The rigidity of the cutter is lowered, and the cutting performance is also lowered.

<Method for producing this laminate>
The manufacturing method of this laminated body is demonstrated below As a manufacturing method of this laminated body, it can manufacture by a well-known method. That is, for example, in the layer (I), the lactic acid resin (A), the inorganic fine particles (B) and other resins and additives are mixed and kneaded so as to have the above-mentioned mixing ratio, and uniaxial or biaxial extrusion is performed. It can produce by extruding with a machine. On the other hand, the layer (II) is prepared by mixing and kneading the lactic acid resin (A), the ethylene copolymer (C) and other resins and additives so as to have the above-mentioned mixing ratio. It can produce by extruding with a screw extruder.

  The layer (I) and the layer (II) can be laminated by coextrusion, extrusion lamination, heat lamination, dry lamination, or the like.

  In the case of coextrusion, the layer (I) and the layer (II) can be combined with a resin through a feed block or a multi-manifold die using a plurality of extruders to produce a laminate. In order to further impart heat resistance and mechanical strength to this layered body, it is preferable to stretch the laminate obtained in the above step uniaxially or biaxially using a roll method, a tenter method, a tubular method, or the like. .

  In the case of extrusion lamination, the lactic acid resin (A), inorganic fine particles (B) and other resins and additives are extruded from a T die, I die, etc. using a single screw or twin screw extruder, and then rolled. A monolayer to be the layer (I) is obtained using a method, a tenter method, a tubular method or the like. Subsequently, when the lactic acid-based resin (A), the ethylene-based copolymer (C) and other resins and additives are extruded from a T die, an I die or the like using a single-screw or twin-screw extruder, casting and At the same time, a laminate can be obtained by laminating the layer (I).

  In the case of thermal laminate and dry laminate, a mixture of lactic acid resin (A), inorganic fine particles (B) and other resins and additives is extruded from a T die, I die, etc. using a single screw or twin screw extruder. A monolayer to be layer (I) is obtained. In addition, using the same method, a layer (II) composed of the lactic acid resin (A), the ethylene copolymer (C) and other resins and additives is prepared. Subsequently, the layer (I) and the layer (II) are laminated by heating or by disposing an adhesive layer between the layers to obtain a laminate having the layer (II) on at least one side of the layer (I). it can.

  In addition, after extending | stretching this laminated body, in order to suppress the thermal contraction of a laminated body, it is preferable to heat-set in the state which hold | gripped the sheet | seat after extending | stretching. Usually, in the roll method, heat setting is performed by contacting a heated roll after stretching, and in the tenter method, heat setting is performed in a state where a sheet is held by a clip. The heat setting temperature depends on the mixing ratio and type of the resin used, but it is preferable to perform heat setting in the range of 100 ° C. or higher and 150 ° C. or lower. Further, for the purpose of further improving the ultrasonic welding performance, the surface of the layer (II) can be subjected to a surface treatment such as a discharge treatment such as a corona treatment or a flame treatment.

Moreover, it is preferable to adjust extending | stretching conditions so that the density of this laminated body may be 1.19 g / cm < ³ > or more and 1.51 g / cm < ³ > or less as mentioned above. Specifically, the stretching temperature range is preferably 65 ° C. or higher and 95 ° C. or lower, more preferably 67 ° C. or higher and 90 ° C. or lower, and further preferably 70 ° C. or higher and 87 ° C. or lower. If it is beyond the lower limit of the range which requires extending | stretching temperature, generation | occurrence | production of the void at the time of extending | stretching can be suppressed, the fall of a density can be prevented and the fall of the rigidity of a film cutter and a cut property can be prevented as a result. On the other hand, if the stretching temperature is not more than the upper limit of the range, the lactic acid resin does not crystallize during stretching, so that sufficient stretching can be performed and the film is not broken.
Further, the area stretching ratio is preferably 3 times or more and 16 times or less, more preferably 4 times or more and 12 times or less, and further preferably 5 times or more and 10 times or less. If it is more than the lower limit of the range which requires an area stretch ratio, the thickness distribution at the time of stretching will not be uneven, and a reduction in cutability can be prevented. On the other hand, if it is below the upper limit of the range where the area stretching ratio is applied, voids in the film can be suppressed during stretching, and a decrease in density can be prevented, and as a result, a decrease in rigidity and cutability of the film cutter can be prevented. it can.

<Production of film cutter>
This laminated body can be cut into a saw blade shape using a Thomson blade or the like as shown in FIG. 1 to produce a film cutter.
However, the shape of the film cutter is not limited to the shape as shown in FIG.

<Storage box with film cutter>
The film cutter manufactured as described above is placed so that the layer (II) is stacked on the front plate, bottom plate, or cover plate of a paper storage box (carton), and fixed by ultrasonic welding. By doing, it can attach to a storage box and can be set as a storage box with a film cutter. Such a storage box with a film cutter can be stored in a state where a thin film such as a wrap film, an aluminum foil, or a cooking sheet is wound around a paper tube or the like.

<Explanation of terms>
“Sheet” generally refers to a product that is thin by definition in JIS and generally has a thickness that is small and flat for the length and width. In general, “film” is compared to the length and width. A thin flat product having an extremely small thickness and an arbitrarily limited maximum thickness, usually supplied in the form of a roll (Japanese Industrial Standard JISK6900). For example, in terms of thickness, in the narrow sense, a film having a thickness of 100 μm or more is sometimes referred to as a sheet, and a film having a thickness of less than 100 μm is sometimes referred to as a film. However, since the boundary between the sheet and the film is not clear and it is not necessary to distinguish the two in terms of the present invention, in the present invention, even when the term “film” is used, the term “sheet” is included and the term “sheet” is used. In some cases, “film” is included.

In the present invention, when expressed as “X to Y” (X and Y are arbitrary numbers), “X is preferably greater than X” and “preferably Y”, with the meaning of “X to Y” unless otherwise specified. It is meant to include “less than”.
Further, in the present invention, when expressed as “more than X” (X is an arbitrary number), unless otherwise specified, it means “preferably greater than X” and includes “Y or less” (Y is an arbitrary number) When expressed as (numerical), it means “preferably smaller than Y” unless otherwise specified.

  Examples are shown below, but the present invention is not limited by these. First, measurement / evaluation methods of physical property values in Examples and Comparative Examples are shown below.

(1) Ultrasonic weldability The laminates produced in the examples and comparative examples were punched into a saw blade shape with a press using a Thomson blade, and a film cutter having a shape shown in FIG. 1 (blade height 1 mm, The blade pitch was 1 mm).
Using an ultrasonic welding machine 450B-FC manufactured by Seidensha Electronics Industry Co., Ltd., place coated cardboard with a thickness of 0.52 mm on the set table with the coated surface down and the uncoated surface up (welded surface). Next, the film cutter (thickness: 280 μm) is placed thereon so that the layer (II) is on the lower side (coated cardboard side), and a circular horn with a diameter of 13 mm from above is placed with a crimping amount of 0.2 mm. The temperature was lowered until it became constant, and ultrasonic welding was performed at an interval of 0.1 second within an oscillation frequency of 19 kHz, a pressure of 0.3 MPa, and a welding time ranging from 0.2 seconds to 0.5 seconds.
Crimping amount = (film cutter thickness + paperboard thickness)-(distance from welding horn tip to set stand)

  The weldability was confirmed by peeling the film cutter and coated cardboard by hand in an atmosphere at 23 ° C. The time required for sufficiently welding the coated cardboard on the film cutter side is “◎” when the time is 0.2 seconds or less, “◯” when 0.3 to 0.4 seconds, The thing of 5 seconds or more was evaluated as "x".

(2) Interlaminar adhesion When the film cutter and the paperboard were peeled in the ultrasonic weldability test, the presence or absence of peeling between the layers (I) and (II) was visually confirmed. The case where peeling between layers was not observed was evaluated as “◯”, and the case where peeling was observed was evaluated as “x”.

(3) Cutability The laminates produced in the examples and comparative examples were punched into a saw blade shape with a press using a Thomson blade, and a film cutter having a shape shown in FIG. A pitch of 1 mm) was produced.
Then, this film cutter was coated with an ultrasonic welding machine using a horn with an oscillation frequency of 19 kHz, a pressure of 0.3 MPa, a welding time of 0.3 seconds, a welding surface width of 3 mm, and a length of 310 mm. This was fixed to (thickness: 520 μm) and boxed, and a wrapping film for food packaging (Mitsubishi Resin Co., Ltd .: Diawrap Eco Pita! Handy, made of polyolefin resin) was housed therein.
The wrap film was set at an angle of 45 degrees with respect to the film cutter, and the stress (40 cm width) was measured when pulled at a speed of 1000 mm / min. In addition, the one where the stress at this time is low is good at the time of cutting, and is excellent in performance as a film cutter. The thing with the stress at the time of a cut of 120 gf / 40 cm or less was set as the pass.

(4) Cut durability The cutability test in the previous section was repeated, and the stress after repeating 1000 times was measured. The thing whose stress at this time is 120 gf / 40 cm or less was set as the pass.

(5) Density Square samples of about 100.0 ± 0.3 mm in length and width were cut out at arbitrary three locations in the width direction of the laminates produced in Examples and Comparative Examples, and 0.001 g of this sample was cut with a precision balance. The weight was measured to the unit. Further, the thickness was measured in units of 0.001 mm at arbitrary nine points of the 100 mm square sample which were appropriately dispersed, and the average thickness was obtained. The volume (cm ³ ) was calculated from the average thickness and area, and the average value of the values obtained by assigning the weight of each sample by each volume was calculated as a density up to a unit of 0.01 g / cm ³ .

<Raw material>
Next, the raw materials used in the following examples and comparative examples will be described.

(Lactic acid resin)
(A) -1: NW4032D manufactured by Nature Works
(Polylactic acid, poly D lactic acid ratio = 1.5 mol%, poly L lactic acid ratio = 98.5 mol%, weight average molecular weight 200,000, ΔHm = 42 J / g)
(A) -2: NW4042D manufactured by Nature Works
(Polylactic acid, poly D lactic acid ratio = 4.3 mol%, poly L lactic acid ratio = 95.7 mol%, weight average molecular weight 200,000, ΔHm = 7 J / g)
(A) -3: NW4060D manufactured by Nature Works
(Polylactic acid, poly D lactic acid ratio = 10.7 mol%, poly L lactic acid ratio = 89.3 mol%, weight average molecular weight 200,000, ΔHm = 0 J / g)

(Inorganic fine particles)
(B) -1: SA-1 manufactured by Sakai Chemical Co., Ltd. (anatase type titanium oxide, average particle size = 0.15 μm, refractive index = 2.52)
(B) -2: B-55 (barium sulfate, average particle size = 0.6 μm, refractive index = 1.65) manufactured by Sakai Chemical Co., Ltd.

(Ethylene copolymer)
(C) -1: Aklift WD201 manufactured by Sumitomo Chemical Co., Ltd.
(Ethylene / methyl methacrylate copolymer, methyl methacrylate content = 10 mass%, Tm = 101 ° C., ΔHm = 89 J / g)
(C) -2: Aklift WH206 manufactured by Sumitomo Chemical Co., Ltd.
(Ethylene / methyl methacrylate copolymer, methyl methacrylate content = 20% by mass, Tm = 89 ° C., ΔHm = 70 J / g)
(C) -3: Everflex EV360 manufactured by Mitsui DuPont Polychemical Co., Ltd.
(Ethylene / vinyl acetate copolymer, vinyl acetate content = 25 mass%, Tm = 80 ° C., ΔHm = 62 J / g)
(C) -4: Everflex EV170 manufactured by Mitsui DuPont Polychemical Co., Ltd.
(Ethylene / vinyl acetate copolymer, vinyl acetate content = 33 mass%, Tm = 52 ° C., ΔHm = 67 J / g)
(C) -5: Everflex EV40LX manufactured by Mitsui DuPont Polychemical Co., Ltd.
(Ethylene / vinyl acetate copolymer, vinyl acetate content = 41 mass%, Tm = 52 ° C., ΔHm = 50 J / g)

The crystal melting heat quantity ΔHm and the crystal melting temperature Tm of the resin were measured from 30 ° C. at a rate of 10 ° C./min using DSC-7 manufactured by Perkin Elmer Co., Ltd. for a sample cut to about 10 mg based on JIS K7121. It heated up to 200 degreeC, and it measured by reading crystal melting calorie | heat amount (DELTA) Hm and crystal melting temperature Tm from the obtained thermogram.
At this time, as in Example 1, for example, when (a) -1 and (a) -3 are mixed at a mixing mass ratio of 20:50 as the lactic acid resin constituting the layer (II), the mixture The heat of crystal fusion ΔHm of the lactic acid resin as was measured and shown in each table.

Example 1
(A) -1 and (b) -1 were mixed at a mixing mass ratio of 90:10, and the layer (I) was formed at 210 ° C. from a two-layer multi-manifold die in a φ40 mm co-directional twin screw extruder. And (a) -1, (a) -3, and (c) -1 were mixed at a mixing mass ratio of 20:50:30. The layer (II) was extruded from the die at 210 ° C. to obtain a coextruded sheet. At this time, the discharge amount of the molten resin was adjusted so that the thickness ratio of the layer (I) and the layer (II) was 9: 1.
Next, the coextruded sheet was quenched with a casting roll at about 55 ° C. to obtain an unstretched sheet.
Next, the film is stretched 2.5 times in the longitudinal direction at a temperature of 75 ° C., stretched 3.0 times in the width direction with a tenter at a temperature of 75 ° C., and further at a temperature of 140 ° C. in the heat treatment zone of the tenter. Heat treatment was performed to produce a laminate.

The amount of molten resin discharged from the extruder and the line speed were adjusted so that the average thickness of the laminate was approximately 280 μm (250 μm for layer (I) and 30 μm for layer (II)).
Table 1 shows the results of evaluating the ultrasonic weldability, interlayer adhesion, cutability, and cut durability of the obtained laminate.

(Example 2)
Example 1 except that a resin composition in which (a) -1, (a) -3 and (c) -2 were mixed at a mixing mass ratio of 20:50:30 was used as the layer (II). Fabrication of the laminate and various evaluations were performed in the same manner. The results are shown in Table 1.

(Example 3)
Example 1 except that a resin composition in which (a) -1, (a) -3 and (c) -3 were mixed at a mixing mass ratio of 20:50:30 was used as the layer (II). Fabrication of the laminate and various evaluations were performed in the same manner. The results are shown in Table 1.

Example 4
Example 1 except that a resin composition in which (a) -1, (a) -3 and (c) -4 were mixed at a mixing mass ratio of 20:50:30 was used as the layer (II). Fabrication of the laminate and various evaluations were performed in the same manner. The results are shown in Table 1.

(Example 5)
Example 1 except that a resin composition in which (a) -1, (a) -3 and (c) -5 were mixed at a mixing mass ratio of 20:50:30 was used as the layer (II). Fabrication of the laminate and various evaluations were performed in the same manner. The results are shown in Table 1.

(Example 6)
As the layer (I), a resin composition in which (a) -1 and (b) -2 are mixed at a mixing mass ratio of 90:10 is used, and as the layer (II), the same resin composition as in Example 2 is used. A laminate was produced and various evaluations were performed in the same manner as in Example 1 except that the product was used. The results are shown in Table 1.

(Example 7)
Production of a laminate in the same manner as in Example 1 except that (a) -1 was used alone as layer (I), and the same resin composition as in Example 2 was used as layer (II), and Various evaluations were made. The results are shown in Table 2.

(Example 8)
Production of a laminate in the same manner as in Example 1 except that a resin composition in which (a) -2 and (c) -2 were mixed at a mixing mass ratio of 70:30 was used as the layer (II). And various evaluation was performed. The results are shown in Table 2.

Example 9
The same as Example 1 except that a resin composition in which (a) -1, (a) -3 and (c) -2 were mixed at a mixing mass ratio of 40:30:30 was used as the layer (II). The laminate was prepared and various evaluations were performed by this method. The results are shown in Table 2.

(Example 10)
As the layer (I), a resin composition obtained by mixing (a) -1, (a) -3 and (b) -1 at a mixing mass ratio of 70:20:10 was used as the layer (II). A laminate was prepared and various evaluations were performed in the same manner as in Example 1 except that the same resin composition as in Example 2 was used. The results are shown in Table 2.

(Example 11)
The same as Example 1 except that a resin composition in which (a) -1, (a) -3 and (c) -2 were mixed at a mixing mass ratio of 30:50:20 was used as the layer (II). The laminate was prepared and various evaluations were performed by this method. The results are shown in Table 2.

(Example 12)
As layer (II), except that a resin composition in which (a) -1, (a) -3 and (c) -2 were mixed at a mixing mass ratio of 30:25:45 was used, the same as in Example 1. The laminate was prepared and various evaluations were performed by this method. The results are shown in Table 2.

(Example 13)
Production of a laminate in the same manner as in Example 1 except that a resin composition obtained by mixing (a) -3 and (c) -2 at a mixing mass ratio of 60:40 was used as the layer (II). And various evaluation was performed. The results are shown in Table 2.

(Comparative Example 1)
As the layer (II), a laminate was prepared and various evaluations were performed in the same manner as in Example 1 except that (a) -3 was used alone. The results are shown in Table 3.
However, since the ultrasonic welding time required 0.5 seconds or more, evaluation of cut property and cut durability was omitted.

(Comparative Example 2)
In Example 1, an unstretched sheet having a thickness of 280 μm (the layer (I) was 250 μm and the layer (II) was 30 μm) was evaluated in the same manner as in Example 1. The results are shown in Table 3.

(Comparative Example 3)
As the layer (I), a resin composition obtained by mixing (a) -1, (a) -2 and (b) -1 at a mixing mass ratio of 50:40:10 is used, and as the layer (II), A laminate was prepared and various evaluations were performed in the same manner as in Example 1 except that the same resin composition as in Example 2 was used. The results are shown in Table 3.

(Comparative Example 4)
Production of a laminate in the same manner as in Example 1 except that a resin composition in which (a) -1 and (c) -2 were mixed at a mixing mass ratio of 70:30 was used as the layer (II). And various evaluation was performed. The results are shown in Table 3.
However, since the ultrasonic welding time required 0.5 seconds or more, evaluation of cut property and cut durability was omitted.

(Comparative Example 5)
The same as Example 1 except that a resin composition in which (a) -1, (a) -3 and (c) -2 were mixed at a mixing mass ratio of 20:25:55 was used as the layer (II). The laminate was prepared and various evaluations were performed by this method. The results are shown in Table 3.
However, since the ultrasonic welding time required 0.5 seconds or more, evaluation of cut property and cut durability was omitted.

(Comparative Example 6)
As the layer (I), a resin composition obtained by mixing (a) -1 and (b) -1 at a mixing mass ratio of 60:40 is used, and as the layer (II), the same resin composition as in Example 2 is used. A laminate was prepared and various evaluations were performed in the same manner as in Example 1 except that was used. The results are shown in Table 3.
However, since the ultrasonic welding time required 0.5 seconds or more, evaluation of cut property and cut durability was omitted.

(Discussion)
When Examples 1 to 13 and Comparative Example 3 are compared, from the viewpoints of cutability and cut durability, the crystal melting heat amount ΔHm of the lactic acid resin (A-1) used for the layer (I) is 30 J / g. It has been found that the above is preferable.
On the other hand, when Examples 1 to 13 are compared with Comparative Examples 1 and 3, from the viewpoint of ultrasonic weldability, the heat of crystal fusion ΔHm of the lactic acid resin (A-2) used for the layer (II) is 0 J / g. As mentioned above, it turned out that it is preferable that it is 25 J / g or less.
Moreover, when Examples 1-13 are compared with the comparative example 5, in layer (II), when the content rate of an ethylene-type copolymer (C) will be 50 mass parts or more, interlayer adhesiveness will become unpreferable. It was found that the content of the ethylene copolymer (C) is preferably 10 parts by mass or more and 50 parts by mass or less.
Furthermore, when Examples 1-13 were compared with the comparative example 2, it turned out that it is important that the laminated body is extended | stretched by at least 1 direction from a viewpoint of cut property and cut durability.

1. 1. Film cutter blade

Claims (10)

  The lactic acid resin (A-1) having a heat of crystal fusion ΔHm of 30 J / g or more is contained in a proportion of 70 parts by mass or more and 100 parts by mass or less, and the inorganic fine particles (B) are 0 parts by mass or more, 30 51 parts by mass or more and 95 parts by mass of lactic acid-based resin (A-2) having a crystal melting heat ΔHm of 0 J / g or more and 25 J / g or less on at least one side of the layer (I) contained in a proportion of parts by mass or less The film cutter is formed from a laminate having a layer (II) containing 5 parts by mass or more and 49 parts by mass or less of the ethylene-based copolymer (C) in a proportion of less than or equal to parts. The film cutter is characterized in that the laminate is stretched in at least one direction.   2. The crystal melting temperature Tm of the ethylene copolymer (C) is 40 ° C. or more and 90 ° C. or less, and the crystal melting heat ΔHm is 1 J / g or more and 100 J / g or less. The film cutter described in 1.   The film cutter according to claim 1 or 2, wherein the ethylene copolymer (C) has a total content of comonomer copolymerized with ethylene of 10% by mass or more and 50% by mass or less. .   The ethylene-based copolymer (C) is an ethylene / vinyl acetate copolymer having a vinyl acetate content of 15% by mass or more and 45% by mass or less, according to any one of claims 1 to 3. Film cutter.   The ethylene-based copolymer (C) is an ethylene / methyl methacrylate copolymer having a methyl methacrylate content of 10% by mass or more and 30% by mass or less. The film cutter as described.   The film cutter according to any one of claims 1 to 5, wherein the inorganic fine particles (B) are inorganic fine particles having a refractive index of 1.6 or more.   The resin composition constituting the layer (I) further contains an ethylene copolymer (C) in a proportion of 0.5 parts by mass or more and 10 parts by mass or less. Crab film cutter.   The film cutter according to any one of claims 1 to 7, wherein the thickness of the layer (I) is from 180 µm to 400 µm and the thickness of the layer (II) is from 3 µm to 100 µm. The density of a film cutter is 1.19 g / cm < ³ > or more and 1.51 g / cm < ³ > or less, The film cutter in any one of Claims 1-8 characterized by the above-mentioned.   A storage box with a film cutter, comprising the film cutter according to any one of claims 1 to 9, wherein the layer (II) is disposed so that the layer (II) overlaps a paper surface of the storage box and is ultrasonically welded.

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