JP2016137541A - Film cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film cutter excellent in film sectility, capable of suppressing a rewinding phenomenon, which is a film cutter containing a polylactic acid-based resin as a constituent material.SOLUTION: There is provided a film cutter having as a main component, one or more layers containing a resin component comprising a polylactic acid-based resin (A) and a resin (B). In the film cutter, a storage elastic modulus (E') at 80°C of the resin (B) is 700 MPa or higher and 5,000 MPa or lower, and the ratio of the resin (B) occupied in the resin component is 0.5 mass% or higher and 50 mass% or lower.SELECTED DRAWING: Figure 1

Description

The present invention is a plastic film cutter mainly composed of a polylactic acid-based resin, which is excellent in slidability with a wrap film and the like, and has a film cutting property (cutting property) equivalent to that of a metal blade. It relates to a film cutter.
The present invention also relates to a storage box with a film cutter provided with the film cutter.

  Thin film such as wrap film, aluminum foil, and cooking sheet is stored in a paper storage box (carton) as a wound body wound around a paper tube, and the required length is pulled out from the storage box when necessary. It is cut with a saw blade film cutter and used.

  The film cutter is required to be excellent in slipperiness with a wrap film or the like in addition to the film cutting property. The reason for this is a so-called unwinding phenomenon in which a thin film film, for example, a wrapping film containing a wrapping film, has a wrapping film whose leading end is in close contact with the surface of the film cutter and enters the container when the lid is opened. This is to prevent it. When this rewinding phenomenon occurs, the leading end of the wrap film sticks to the peripheral surface of the wound body of the wrapping film in the storage box, so that it becomes difficult to take out the leading end of the wrap film at the next use.

  Conventionally, many metal cutters are used for this type of film cutter, and it has been proposed to prevent rewinding by adjusting the surface roughness of the metal cutter (Patent Document 1). . However, the metal cutter is excellent in cutability, but it remains unburned if it is incinerated at the time of disposal, so it has to be taken out from the storage box each time and discarded.

From such a point of view, paper cutters and plastic cutters, particularly biodegradable plastic cutters have been proposed instead of metal cutters.
As a biodegradable plastic cutter, for example, a film cutter mainly composed of a polylactic acid resin, which is a plant-derived resin such as corn, has been proposed (Patent Document 2, Patent Document 3, and Patent Document 4). Since the starting material is derived from a plant, it is possible to save exhaustible resources.
Film cutters based on polylactic acid resin have film cutting properties and cutting durability that are almost the same as metal cutters, but rewinding phenomenon is likely to occur. In some cases, this may cause inconvenience in use.

  As in Patent Document 1, in metal cutters, studies have been made to suppress the rewinding phenomenon by optimizing the surface roughness by roughening treatment, but in plastic film cutters, Since roughening treatment like a metal cutter is difficult, it is necessary to adopt a measure different from that of a metal cutter.

JP-A-3-069444 JP-A-11-99498 Japanese Patent Application Laid-Open No. 2005-212064 JP 2011-42027 A

  As described above, the film cutter mainly composed of a polylactic acid resin has a problem of a rewinding phenomenon.

  The present invention is a film cutter comprising a polylactic acid-based resin as a constituent material, and has a film cutter capable of suppressing the rewinding phenomenon, and a storage box with a film cutter provided with the film cutter. The issue is to provide.

  As a result of intensive studies in view of the above circumstances, the present inventors have blended a polylactic acid resin (A) with a resin (B) having a specific storage elastic modulus (E ′) at a predetermined ratio, The present inventors have found that the above problems can be easily solved, and have completed the present invention.

  That is, according to the first invention of the present invention, there is provided a film cutter having at least one layer composed mainly of a resin component comprising a polylactic acid resin (A) and a resin (B), wherein the resin (B) The film cutter is characterized in that the storage elastic modulus (E ′) at 80 ° C. is 700 MPa or more and 5000 MPa or less, and the ratio of the resin (B) in the resin component is 0.5 mass% or more and 50 mass% or less. Is provided.

  Furthermore, according to the second invention of the present invention, in the first invention, there is provided a film cutter characterized by being stretched in at least one direction.

  Furthermore, according to the third invention of the present invention, in the first or second invention, the resin (B) is a polystyrene resin, an acrylic resin, an amorphous polyester resin, an amorphous polyamide resin, and A film cutter is provided that is one or more selected from polycarbonate resins.

  According to a fourth aspect of the present invention, there is provided the film cutter according to the third aspect, wherein the resin (B) is a polystyrene resin.

  Furthermore, according to the fifth invention of the present invention, in any one of the first to fourth inventions, the static friction coefficient with respect to the polyvinyl chloride resin wrap film measured according to JIS K7125 is 0.4 or more and 0.7 or less. A film cutter is provided.

  According to 6th invention of this invention, a storage box with a film cutter provided with the film cutter of any one of 1st-5th invention is provided.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in film cutability, the film cutter which can suppress a rewinding phenomenon, and a storage box with a film cutter provided with this film cutter are provided.

In an Example, it is a front view of the film cutter produced by evaluation of the rewinding phenomenon.

  Hereinafter, although an example of embodiment of this invention is demonstrated, this invention is not limited to embodiment described below, unless the summary is exceeded.

[Explanation of terms]
“Sheet” generally refers to a product that is thin by definition in JIS and has a thickness that is small and flat for the length and width. In general, “film” is thicker than the length and width. A thin flat product with 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), unless otherwise noted, “preferably greater than X” and “preferably greater than Y” together with the meaning of “X to Y”. It is meant to include “small”.
Further, in the present invention, when expressed as “X or more” (X is an arbitrary number), the meaning of “preferably greater than X” is included unless otherwise specified, and “Y or less” (Y is an arbitrary number) ), The meaning of “preferably smaller than Y” is included unless otherwise specified.

In addition, the average particle diameter of the acrylic resin and inorganic fine particles in the present invention mainly indicates the value of D ₅₀ measured by a laser diffraction method.

[Film cutter]
The film cutter of the present invention is a layer mainly composed of a resin component comprising a polylactic acid resin (A) and a resin (B) (hereinafter, this layer may be referred to as “(A) / (B) layer”). The storage elastic modulus (E ′) at 80 ° C. of the resin (B) is 700 MPa or more and 5000 MPa or less, and the ratio of the resin (B) to the resin component is 0.00. It is 5 mass% or more and 50 mass% or less, It is characterized by the above-mentioned.
Here, the “main component” is preferably 60% by mass or more, more preferably 70% by mass or more, and further preferably 95 to 100% by mass as a component in the (A) / (B) layer. Say things.

The film cutter of this invention may consist of a single layer film which consists only of (A) / (B) layers, (A) / (B) layers of two or more layers, or (A) / ( It may be a laminated film of the B) layer and a layer other than the (A) / (B) layer. However, since the (A) / (B) layer is a layer for suppressing the rewinding phenomenon by the slipperiness of the surface, in the case of a laminated film, the (A) / (B) layer is the surface of the film cutter. Provided as a layer.
Below, the film which consists of (A) / (B) layer which comprises the film cutter of this invention, or the laminated | multilayer film containing a (A) / (B) layer may be called "the film of this invention."

1. Polylactic acid resin (A)
Examples of the polylactic acid resin (A) 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 lactic acid) whose structural units are L lactic acid and D lactic acid. Or a mixed resin thereof. Moreover, the copolymer of these, (alpha) -hydroxycarboxylic acid, diol, and / or 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 polylactic acid resin (A), the optimal amount of heat of crystal melting for the (A) / (B) layer It is preferable to adjust to (ΔHm). That is, by optimizing the ratio (molar ratio) between L-lactic acid (L-form) and D-lactic acid (D-form), the heat of crystal melting (ΔHm) of the polylactic acid resin (A) is 30 J / g or more. It is preferable to adjust so that it becomes.

If the heat of crystal melting (ΔHm) of the polylactic acid-based resin (A) is 30 J / g or more, the strength as a film cutter can be sufficiently maintained, and the cut property can be sufficiently improved.
From this viewpoint, the heat of crystal fusion (ΔHm) of the polylactic acid resin (A) is more preferably adjusted to 35 J / g or more, and more preferably 40 J / g or more.
The upper limit of the heat of crystal melting (ΔHm) of the polylactic acid resin (A) is not particularly required. The higher the heat of crystal melting (ΔHm), the higher the strength, and the performance as a film cutter, that is, a plastic blade. Can be fully exhibited.

For example, in a molar ratio, L-form / D-form = 100/0 to 97/3, or L-form / D-form = 0/100 to 3/97 polylactic acid resin (A-1) and L-form / D lactic acid = 97/3 to 85/15, or 3/97 to 15/85 polylactic acid resin (A-2) is mixed at a mass ratio of 100/0 to 50/50 to obtain polylactic acid. It is preferable to adjust so that the heat of crystal fusion (ΔHm) of the system resin (A) is 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.
The heat of crystal fusion (ΔHm) of the polylactic acid resin (A) is measured by the method described in the Examples section below. In the examples described later, the heat of crystal fusion (ΔHm) is simply described as “ΔHm”.

As described above, the polylactic acid resin (A) may be a copolymer with a diol such as an α-hydroxycarboxylic acid or an aliphatic diol and / or a dicarboxylic acid such as an aliphatic dicarboxylic acid.
At this time, as the α-hydroxycarboxylic acid copolymerized with the polylactic acid resin, optical isomers of lactic acid (D-lactic acid for L-lactic acid, L-lactic acid for D-lactic acid), glycol 2 such as 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 thereof include functional aliphatic hydroxycarboxylic acids and lactones such as caprolactone, butyrolactone, and valerolactone.
Examples of the aliphatic diol copolymerized with the polylactic acid resin include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, and the aliphatic dicarboxylic acid includes succinic acid, adipic acid, Examples include suberic acid, sebacic acid, dodecanedioic acid and the like.

As a polymerization method for the polylactic acid-based resin, a condensation polymerization method, a ring-opening polymerization method, and other known polymerization methods can be employed. For example, in the polycondensation method, L-lactic acid or D-lactic acid, or a mixture thereof can be directly dehydrated and polycondensed to obtain a polylactic 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. These can be mixed and polymerized as necessary to obtain a polylactic acid resin having any desired composition and crystallinity.

As necessary, such as further improving the heat resistance, terephthalate is used as a small amount copolymerization component in a range not impairing the essential properties of the polylactic acid resin, that is, in a range containing 90% by mass or more of the polylactic acid resin component. A non-aliphatic dicarboxylic acid such as an acid or a non-aliphatic diol such as an ethylene oxide adduct 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 polylactic acid resin (A) is preferably 50,000 or more and 400,000 or less, and more preferably 100,000 or more and 250,000 or less. If the weight average molecular weight of the polylactic acid resin (A) is not less than the lower limit of this range, preferable practical physical properties can be obtained, and if it is not more than the upper limit, the melt viscosity will not be too high. Moldability can be obtained.

  A typical example of the polylactic acid resin (A) preferably used in the present invention is “Nature Works” manufactured by Nature Works, etc., as commercially available products.

2. Resin (B)
The resin (B) used in the present invention has a storage elastic modulus (E ′) at 80 ° C. of 700 MPa or more and 5000 MPa or less, and is a resin that disperses without being compatible with the polylactic acid resin (A). By dispersing the resin (B) in the polylactic acid resin (A), it is possible to enhance the slipperiness of the film surface of the present invention and to obtain the effect of suppressing the reverse phenomenon according to the present invention.

The storage elastic modulus (E ′) at 80 ° C. of the resin (B) is 700 MPa or more and 5000 MPa or less, preferably 1000 MPa or more and 4000 MPa or less, particularly preferably 1500 MPa or more and 3000 MPa or less in order to obtain the effect of suppressing the rewinding phenomenon. .
If the storage elastic modulus (E ′) of the resin (B) is 700 MPa or more, the slipperiness can be enhanced in a state where the resin (B) is dispersed in the polylactic acid resin (A) when stretched. On the other hand, if it is 5000 MPa or less, the film can be stretched without breaking without inhibiting the stretchability of the film.

  The storage elastic modulus (E ′) of the resin (B) is measured by the method described in the Examples section below. In the examples described later, the storage elastic modulus (E ′) at 80 ° C. is simply referred to as “E ′”.

As what can be employ | adopted as resin (B), a polystyrene-type resin, an acrylic resin, an amorphous polyester-type resin, an amorphous polyamide-type resin, a polycarbonate-type resin etc. are mentioned, for example.
In particular, by using a polystyrene-based resin as the resin (B), it is possible to provide a film cutter that can provide a more excellent effect of improving slipperiness and that does not cause problems in appearance and handling.

<Polystyrene resin>
Examples of the polystyrene resin used as the resin (B) of the present invention include GPPS (general purpose polystyrene), HIPS (impact polystyrene), SBS (styrene-butadiene-styrene copolymer), SIS (styrene-isoprene-styrene). Copolymer), SEBS (styrene-ethylene-butylene-styrene copolymer), SEPS (styrene-ethylene-propylene-styrene copolymer), styrene-carboxylic acid copolymer, or organic such as these copolymers Examples of the fine particles include those having a high degree of crosslinking. GPPS is preferably used from the viewpoint of rigidity.

  Representative examples of the above-mentioned polystyrene resins include GPPS “G9305” manufactured by PS Japan, SBS “Asaflex” series manufactured by Asahi Kasei Chemicals, and SEBS “Tough Tech” series manufactured by Asahi Kasei Chemicals. And Kuraray's “Septon” series are commercially available.

<Acrylic resin>
The acrylic resin used as the resin (B) of the present invention is preferably a bead-form crosslinkable acrylic resin (crosslinked acrylic beads). The bead-form crosslinkable acrylic resin is a suspension polymerized by blending a small amount of a crosslinkable monomer (for example, allyl methacrylate, triallyl cyanurate) with a non-crosslinkable monomer mainly composed of an acrylic monomer.

As the non-crosslinking monomer, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, propyl methacrylate, butyl methacrylate and the like can be used alone or in combination of two or more, but those mainly composed of methyl methacrylate are particularly preferred. preferable. Moreover, a crosslinking | crosslinked monomer can be mix | blended in the range of 1-5 mass parts with respect to 100 mass parts of non-crosslinking monomers, for example.
As the bead-like crosslinkable acrylic resin, crosslinked polymethyl methacrylate (PMMA) particles are particularly preferable.

  The average particle size of the bead-shaped crosslinkable acrylic resin used in the present invention is preferably 1 μm or more and 20 μm or less, and particularly preferably 1 μm or more and 3 μm or less. When the average particle diameter is 1 μm or more, the protrusion can be made on the surface of the (A) / (B) layer and the slipperiness can be improved. Moreover, it is easy to disperse | distribute uniformly in the kneading | mixing process as an average particle diameter is 1 micrometer or more. On the other hand, when the average particle size exceeds 20 μm, the mechanical strength of the (A) / (B) layer is reduced, and there is a risk of falling off. If the average particle size is 3 μm or less, the appearance of the film of the present invention can be kept good even after the resin protrudes to the surface of the (A) / (B) layer in the stretching step.

  Typical examples of the acrylic resin include those that are commercially available such as “Chemisnow” series manufactured by Soken Chemical Co., Ltd. and “Gantzpearl” series manufactured by Aika Industry.

<Amorphous polyester resin>
The amorphous polyester resin used as the resin (B) of the present invention is increased from −50 ° C. to 300 ° C. at a heating rate of 10 ° C./min by a differential thermal scanning calorimeter (DSC) according to JIS K7121. Warm, hold at 300 ° C. for 1 minute, cool down to −50 ° C. at a cooling rate of 10 ° C./minute, hold at −50 ° C. for 1 minute, and then heat up to 300 ° C. at a heating rate of 10 ° C./minute In this case, the polyester resin does not show a clear melting peak at the second temperature rise, and is preferably obtained using two or more kinds of diol components as a copolymer raw material. In addition, at least one of the diol components of the polyester resin raw material is preferably a relatively bulky diol having a cyclic structure in the molecule. The cyclic structure is preferably a cyclic structure containing no double bond, and may contain an oxygen atom derived from an ether bond in the molecule.

  Examples of such bulky diol components include 3,9-bis (1,1-dimethyl-2-dihydroxyethyl) -2,4,8,10-tetraoxaspiro- (5,5) -undecane , Spiroglycol), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (hereinafter referred to as TMCD), (3S, 3aα, 6aα) -hexahydrofuro [3,2-b ] Furan-3α, 6β-diol (hereinafter referred to as isosorbide), tricyclodecane dimethanol, and the like.

  Examples of diol components other than the above include diethylene glycol, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, neo Pentyl glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene glycol, cyclohexanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, p-xylenediol, bisphenol A, tetrabromo Examples thereof include bisphenol A and tetrabromobisphenol A-bis (2-hydroxyethyl ether). Among these, ethylene glycol is preferable because it is industrially inexpensive and easy to control crystallinity and glass transition temperature.

  The content ratio of the bulky diol component in the amorphous copolymer polyester resin is preferably 20 mol% or more with respect to the total diol component contained in the amorphous copolymer polyester resin. It is more preferably at least mol%, particularly preferably at least 40 mol%. Further, the upper limit of the content ratio of the bulky diol component is not particularly limited, but if the content ratio is excessively high, depending on the type of the diol component, there is a possibility that problems such as loss of fluidity at the time of melting may occur. It is preferable that it is below mol%.

  Examples of the dicarboxylic acid component used in the amorphous copolyester resin include terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2,5-dichloroterephthalic acid, 2-methylterephthalic acid, 4,4-stilbene Dicarboxylic acid, 4,4-biphenyldicarboxylic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, bisbenzoic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4 -Aromatic dicarboxylic acids such as diphenyl ether dicarboxylic acid, 4,4-diphenoxyethane dicarboxylic acid, 5-Na sulfoisophthalic acid, ethylene-bis-p-benzoic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohex Aliphatic dicarboxylic acids such as Njikarubon acid. These dicarboxylic acid components may be used alone or in admixture of two or more. In the present invention, terephthalic acid and isophthalic acid are particularly preferable as the dicarboxylic acid component because it is industrially inexpensive and the synthesized amorphous copolyester resin is chemically stable.

  The intrinsic viscosity (IV) of the amorphous copolyester resin measured by an Ubbelohde viscometer according to JIS K7367 is not particularly limited, but is usually 0.5 dl / g or more and 0.9 dl / g or less. It is preferably 0.6 dl / g or more and 0.8 dl / g or less. If the intrinsic viscosity (IV) is in the above range, it is preferable because the mechanical strength of the (A) / (B) layer and the fluidity at the time of melting can be made compatible.

  The glass transition temperature (Tg) of the amorphous copolyester resin is measured by heating at a heating rate of 10 ° C / min from -50 ° C to 300 ° C by DSC according to JIS K7121, and is 80 ° C or higher. Is required, more preferably 85 ° C. or higher, further preferably 90 ° C. or higher, and particularly preferably 95 ° C. or higher. The upper limit of the glass transition temperature (Tg) is not particularly limited, but is usually 130 ° C. or lower. When the glass transition temperature (Tg) of the amorphous copolymerized polyester resin is less than 80 ° C., the heat resistance under the stretching temperature condition of the film of the present invention is not preferable. A glass transition temperature (Tg) can be made into a preferable range by adjusting the copolymerization component of an amorphous copolymerization polyester-type resin in the said range.

  Representative examples of the above amorphous polyester resins include “ALTERSTER” (using spiroglycol) manufactured by Mitsubishi Gas Chemical Co., Ltd., “TRITAN” (using TMCD) manufactured by EASTMAN Chemical, and SK Chemical. “ECOZEN” (using isosorbide) is commercially available.

<Amorphous polyamide resin>
The amorphous polyamide resin used as the resin (B) of the present invention refers to a polyamide resin having a heat of crystal fusion (ΔHm) of less than 5 J / g.

The dicarboxylic component constituting the amorphous polyamide-based resin is not particularly limited, and may be any of dicarboxylic acids derived from aromatic dicarboxylic acids, aliphatic carboxylic acids, and hydroxycarboxylic acids.
Moreover, the diamine component which comprises the said amorphous polyamide-type resin is not specifically limited, Any of aromatic diamine and aliphatic diamine may be sufficient.
In order to constitute an amorphous polyamide resin having a heat of crystal fusion (ΔHm) of less than 5 J / g, it is preferable that either the dicarboxylic acid component or the diamine component is bulky.

  Specific examples of such amorphous polyamide resins include polyhexamethylene isophthalamide (polyamide 6I), polybis (3-methyl-4-aminohexyl) methane terephthalamide (polyamide PACMT), polybis (3-methyl-4- Aminohexyl) methane isophthalamide (polyamide PACMI), polybis (3-methyl-4-aminohexyl) methane dodecamide (polyamide PACM12), polybis (3-methyl-4-aminohexyl) methane tetradecamide (polyamide PACM14), Or a mixture thereof may be mentioned, but the invention is not limited to these.

The glass transition temperature (Tg) of the amorphous polyamide-based resin is preferably 100 ° C. or higher and 200 ° C. or lower, more preferably 110 ° C. or higher and 190 ° C. or lower, and 120 ° C. or higher and 180 ° C. or lower. Further preferred.
When the glass transition temperature (Tg) is 100 ° C. or higher, the film of the present invention is excellent in heat resistance and dimensional stability. On the other hand, if the glass transition temperature (Tg) is 200 ° C. or less, the moldability and toughness are excellent.
In addition, the glass transition temperature (Tg) of the amorphous polyamide-based resin is a strain of 0.1%, using a viscoelastic spectrometer DVA-200 (manufactured by IT Measurement Control Co., Ltd.) according to JIS K7244-10. This is a temperature that shows the main dispersion peak of loss tangent (tan δ) when dynamic viscoelasticity temperature dispersion measurement is performed at a frequency of 10 Hz and a heating rate of 3 ° C./min.

  As typical examples of the amorphous polyamide-based resin, “SELAR” manufactured by Mitsui DuPont Chemical Co., Ltd. and “Unitika Nylon 6” manufactured by Unitika Co., Ltd. are commercially available.

<Polycarbonate resin>
Examples of the polycarbonate resin used as the resin (B) of the present invention include those produced by reacting a dihydric phenol with a carbonate precursor such as phosgene or a carbonate compound. The polycarbonate resin is produced, for example, by a reaction between a dihydric phenol and a carbonate precursor such as phosgene in a solvent such as methylene chloride. Or it can obtain by transesterification with carbonate precursors, such as a dihydric phenol and a carbonate ester compound, in the presence or absence of a solvent.

  Divalent phenols include 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 2,2-bis. Bis (4-hydroxyphenyl) alkane compounds such as (4-hydroxy-3,5-dimethylphenyl) propane and 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) Examples thereof include sulfide and bis (4-hydroxyphenyl) sulfone, and bis (4-hydroxyphenyl) alkane compounds, particularly bisphenol A, is preferable. These dihydric phenols may be used alone or in combination of two or more.

  Examples of the carbonate precursor include carbonyl halide, carbonyl ester, or haloformate, and examples thereof include phosgene, diphenyl carbonate, dihaloformate of divalent phenol, and a mixture thereof.

  The polycarbonate resin used in the present invention may be a homopolymer using one of the dihydric phenols, or may be a copolymer using two or more. Furthermore, the thermoplastic random branched polycarbonate resin obtained by using a polyfunctional aromatic compound together with the said bihydric phenol may be sufficient. Furthermore, it may be a mixture of two or more of various polycarbonate resins.

  Typical examples of the polycarbonate resin include “Iupilon” manufactured by Mitsubishi Engineering Plastics and “Caliver” manufactured by Sumitomo Dow.

3. Inorganic fine particles (C)
In the (A) / (B) layer, inorganic fine particles (C) can be blended as necessary for the purpose of enhancing the visibility when using the film cutter and ensuring safety.

  As inorganic fine particles (C), talc, kaolin, calcium carbonate, bentonite, mica, sericite, glass flake, 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, zonotolite, sepiolite, whisker, glass fiber, glass flake, metal powder, beads, silica balloon, A shirasu balloon can be mentioned. Any one of these can be used alone, or two or more can be used in combination.

Among these, by using a material having a refractive index of 1.6 or more, particularly 2.0 or more, it is possible to efficiently provide concealability with a lower addition amount and to obtain excellent visibility.
Specific examples of inorganic fine particles having a refractive index of 1.6 or more, particularly 2.0 or more include barium sulfate, magnesia, zinc oxide, zinc sulfide, zircon oxide, potassium titanate, lead titanate, and titanium oxide. However, it is particularly preferable to blend titanium oxide having the highest refractive index.

  The average particle size of the inorganic fine particles (C) is preferably 0.1 μm to 5 μm, more preferably 0.15 μm to 3 μm. If the average particle diameter is 5 μm or less, the inorganic fine particles (C) are unlikely to become the starting point of destruction, and thus 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 (C) are less likely to aggregate, and therefore, it is preferable that poor dispersion hardly occur.

4). Content ratio of each component The content ratio of the polylactic acid resin (A) in the (A) / (B) layer is 100% by mass of the resin component that is the total of the polylactic acid resin (A) and the resin (B). 50 mass% or more and 99.5 mass% or less, preferably 60 mass% or more and 98 mass% or less, particularly preferably 70 mass% or more and 97.5 mass% or less.
On the other hand, the content ratio of the resin (B) is 0.5% by mass or more and 50% by mass or less, preferably 100% by mass of the resin component which is the total of the polylactic acid resin (A) and the resin (B). Is 2% by mass or more and 40% by mass or less, and particularly preferably 2.5% by mass or more and 30% by mass or less.
If the content of the polylactic acid resin (A) is 50% by mass or more, particularly 70% by mass or more, the rigidity and heat resistance of the polylactic acid resin (A) can be maintained, and performance as a film cutter Can be fully demonstrated.
On the other hand, if the content ratio of the resin (B) is 0.5% by mass or more, the rewinding phenomenon can be effectively prevented, and if it is 50% by mass or less, the film breaks in the stretching step. And can be stretched.

The inorganic fine particles (C) are optional components, and the (A) / (B) layer may not contain the inorganic fine particles (C). The content of the inorganic fine particles (C) in the (A) / (B) layer is 0% by mass or more with respect to 100% by mass in total of the polylactic acid resin (A), the resin (B), and the inorganic fine particles (C). It is preferably 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, further preferably 0.5% by mass or more and 15% by mass or less, and particularly preferably 1% by mass or more and 10% by mass or less. It is as follows.
When the (A) / (B) layer contains inorganic fine particles (C), if the content is 0.1% by mass or more, the concealing property of the film cutter is sufficient and the visibility during use is sufficient. Therefore, safety during handling can be improved. On the other hand, if the content of the inorganic fine particles (C) is 30% by mass or less, generation of voids at the interface between the resin component and the inorganic fine particles (C) can be suppressed in the stretching process during film cutter production. Moreover, it can prevent that the rigidity of a film cutter falls or the cutting property of various films is impaired.

  In addition, the (A) / (B) layer according to the present invention includes 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. Etc., additives other than polylactic acid-type resin (A) and resin (B) can be mix | blended.

5. Other Layers The film of the present invention may be composed of a single (A) / (B) layer or a laminated film of two (A) / (B) layers. Moreover, the laminated film of layers other than (A) / (B) layer and (A) / (B) layer may be sufficient. For example, the (A) / (B) layer is used as the front and back layers, and a layer other than the (A) / (B) layer (hereinafter sometimes referred to as “other layer”) is provided as an intermediate layer therebetween. The obtained three-layer laminated film may be used. Moreover, the double-layer laminated film of (A) / (B) layer and another layer may be sufficient. In the case of this two-layer laminated film, in the storage box with a film cutter, the (A) / (B) layer is provided so as to be a contact surface with a wrap film or the like.
By using a laminated film in which other layers are laminated on the (A) / (B) layer, rigidity, mechanical properties, cutability, heat resistance, and the like can be improved.

  Although there is no restriction | limiting in particular as another layer, The thing which has as a main component the polylactic acid-type resin (A) or the polylactic acid-type resin (A) and the above-mentioned inorganic fine particle (C) is preferable, and the above-mentioned (A ) / (B) For the same reason as the content of the inorganic fine particles (C) in the layer, 0% of the inorganic fine particles (C) are added to 100% by mass of the total of the polylactic acid resin (A) and the inorganic fine particles (C). It is preferable to contain not less than 30% by mass and not more than 30% by mass, in particular not less than 0.1% by mass and not more than 20% by mass, and more preferably not less than 0.5% by mass and not more than 15% by mass, especially 1% by mass to 10% by mass.

  For these other layers, additives such as ultraviolet absorbers, light stabilizers, antioxidants, plasticizers, nucleating agents, lubricants, pigments, dyes, and polylactic acid-based resins (insofar as the effects of the present invention are not impaired) Resins other than A) can be blended.

6). Production method of the film of the present invention The film of the present invention can be produced by a known method. For example, the film of the present invention consisting of only one (A) / (B) layer comprises a polylactic acid resin (A), a resin (B), inorganic fine particles (C) used as necessary, and other resins. And an additive can be mixed and kneaded so as to have the above-mentioned mixing ratio, and extruded by a single screw or twin screw extruder.
Moreover, in the case of the film of the present invention consisting of a laminate film of two layers or three or more layers, the other layers are polylactic acid resin (A), inorganic fine particles (C) used as necessary, and other resins. And an additive can be mixed and kneaded so as to have the above-mentioned mixing ratio, and extruded by a single screw or twin screw extruder.

  The (A) / (B) layer and other layers can be laminated by coextrusion, extrusion lamination, heat lamination, dry lamination, or the like.

  In the case of coextrusion, a laminated film can be produced by joining the (A) / (B) layer and other layers through a feed block or a multi-manifold die using a plurality of extruders.

  The film of the present invention is preferably stretched in at least one direction. By stretching in at least one direction, a film cutter excellent in rigidity, mechanical properties, film cutting property, and heat resistance can be formed.

  The stretching conditions are preferably adjusted so that the density of the film of the present invention falls within the preferred range described below. 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 rigidity of a film cutter and the fall of film cutting 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 polylactic acid resin (A) is not crystallized at the time of stretching, so that sufficient stretching can be performed and the film is not broken.

  Further, the draw ratio is preferably 2 to 16 times, more preferably 3 to 12 times, and still more preferably 4 to 9 times in terms of area magnification. If the area stretch ratio is equal to or more than the lower limit of the range, there is no unevenness in the thickness distribution during stretching, and it is possible to prevent the film from being cut. 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 of the film cutter and a film cutting property can be prevented. Can do.

  After the above stretching treatment, it is preferable to perform heat treatment (heat setting) while holding the stretched film in order to suppress thermal shrinkage. Usually, in the roll method, heat treatment is performed by bringing the film into contact with a heated roll after stretching, and in the tenter method, the heat treatment is performed with the film held by a clip. The heat treatment temperature is preferably in the range of 100 ° C. or higher and 150 ° C. or lower, although it depends on the mixing ratio and type of resin used. By performing such heat treatment, more excellent heat resistance and mechanical properties can be imparted.

7). Physical properties of the film of the present invention The thickness of the (A) / (B) layer varies depending on the layer structure of the film of the present invention, but the thickness per layer of the (A) / (B) layer is 180 μm or more and 400 μm or less. Preferably, it is 200 μm or more and 380 or less, and more preferably 220 μm or more and 350 μm or less. When the thickness of the (A) / (B) layer is not less than the lower limit of the above range, the (A) / (B) layer has sufficient rigidity when cutting a wrap film or the like as a film cutter. On the other hand, film cutting property etc. can be maintained by being below the upper limit of the said range.

  When the film of the present invention is a laminated film with the other layers described above, the thickness of the other layers is preferably 3 μm or more and 100 μm or less, more preferably 5 μm or more and 80 or less, and more preferably 10 μm or more. More preferably, it is 50 μm or less. When the thickness of the other layer is equal to or greater than the lower limit of the above range, the above-described effects due to the provision of the other layer can be effectively obtained. On the other hand, by being below the upper limit of the above range, the rigidity and mechanical properties as a film cutter can be maintained.

  In particular, the film of the present invention is a film having a total thickness of 183 μm or more and 500 μm or less, particularly 205 μm or more and 460 μm or less, particularly 230 μm or more and 400 μm or less by forming a laminated film of the (A) / (B) layer and other layers. It is preferable that By using a film having a thickness within such a range, a film cutter having excellent rigidity, mechanical properties, film cutting properties, and heat resistance can be provided.

The density of the film of the present invention is preferably equal to or less than 1.19 g / cm ³ or more 1.51 g / cm ^3, in particular 1.20 g / cm ³ or more 1.48 g / cm ³ or less, especially 1.24 g / cm ^It is preferably ³ or more and 1.41 g / cm ³ or less. If the density of the film of this invention exists in the said range, it can be set as the film cutter excellent in rigidity and film cutability.

8). Production of Film Cutter The film of the present invention can be produced by cutting the film of the present invention into a saw blade shape as shown in FIG.
However, the shape of the film cutter of the present invention is not limited to the shape shown in FIG.

9. Physical properties of film cutter The film cutter of the present invention has a coefficient of static friction with respect to a polyvinyl chloride resin wrap film, measured according to JIS K7125 with respect to the (A) / (B) layer, in particular 0.4 to 0.7, in particular. It is preferably 0.5 or more and 0.6 or less.
If the value of the static friction coefficient is less than 0.4, the slipping property between the films becomes excessive, and it becomes difficult to wind up the film of the present invention in the production process and the processing process. On the other hand, when it exceeds 0.7, the slipperiness with the wrap film is poor and rewinding phenomenon is likely to occur.

The film cutter of the present invention preferably has a surface roughness of 25 nm or more and 1000 nm or less with respect to the (A) / (B) layer as measured by the method described in the Examples section below.
When the surface roughness is within the above range, the static friction coefficient can be easily adjusted to the above range, and the rewinding phenomenon suppressing effect can be excellent without impairing productivity and workability. A more preferable surface roughness is 50 nm or more and 500 nm or less.

[Storage box with film cutter]
The film cutter of the present invention is applied to a thin film film in which the (A) / (B) layer side is stored in a storage box on the front surface, bottom plate, or cover plate of a paper storage box (carton). By arrange | positioning so that it may become the side to contact | connect and it adheres by ultrasonic welding, 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.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples.

[Measurement and evaluation method]
Methods for measuring and evaluating physical properties and the like in Examples and Comparative Examples are as follows.

(1) Measurement of coefficient of static friction In order to evaluate the slipperiness of the films obtained in each of the examples and comparative examples, a wrap film (made by Mitsubishi Plastics Co., Ltd .: trade name “Diawrap”, polychlorinated) was evaluated according to JIS K7125. The static friction coefficient was measured with a vinyl resin (thickness: 13 μm, width: 30 cm). The static friction coefficient was measured twice with respect to the width direction of the film obtained in each of the examples and comparative examples, and the average value was evaluated.

(2) Measurement of surface roughness (arithmetic average roughness) For the films obtained in each of the examples and comparative examples, the arithmetic average roughness of the surface was measured according to the following equipment and conditions, and the surface smoothness of the film was measured. evaluated.
Apparatus: Direct phase interference microscope VertScan 2.0 (manufactured by Ryoka System Co., Ltd.)
Condition: Observation mode Wave mode
Field of view 939.87 × 713.17 μm

(3) Evaluation of rewinding phenomenon The film obtained in each Example and Comparative Example was punched into a saw blade shape with a press using a Thomson blade, and a film cutter having a shape shown in FIG. The blade pitch was 1 mm).
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. Adhered to (thickness 520 μm), this is made into a box, and a wrap film for food packaging (Mitsubishi Resin Co., Ltd .: trade name “Diawrap”, made of polyvinyl chloride resin, thickness: 13 μm, width) : 30 cm).
The wrap film was set at an angle of 45 ° with respect to the film cutter, and it was evaluated whether or not the wrap film rewinds when cut 300 times. Of 300 times, the number of times of rewinding was 5 or less was marked with “◯”, and the number of times of rewinding 6 times or more was marked with “X”.

(4) Measurement of heat of crystal melting (ΔHm) The heat of crystal melting (ΔHm) of the resin is 10 ° C./min using DSC-7 manufactured by Perkin Elmer Co., Ltd. for a sample cut to about 10 mg based on JIS K7121. The temperature was increased from 30 ° C. to 200 ° C. at a rate, and the crystal melting heat amount (ΔHm) was read from the obtained thermogram.

(5) Measurement of storage elastic modulus (E ′) After compressing each resin for 1 minute at a load of 20 MPa with a hot press heated within a set temperature range of 180 ° C. to 230 ° C., it is cooled and molded into a sheet shape, The obtained film was accurately cut into a size of 4 mm wide × 80 mm long to prepare a sample. Using a viscoelastic spectrometer DVA-200 (manufactured by IT Measurement Co., Ltd.) under the conditions of a vibration frequency of 10 Hz, a strain of 0.1%, a heating rate of 3 ° C./min, and a chuck distance of 1 cm, the measurement temperature is from −100 ° C. to 200 ° C. Dynamic viscoelasticity was measured in the range of ° C.

[material]
The film raw materials used in Examples and Comparative Examples are as follows.

<Polylactic acid resin (A)>
(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)

<Resin (B) with E ′ of 700 MPa to 5000 MPa>
(B) -1: G9305 manufactured by PS Japan (polystyrene, E ′ = 2400 MPa)
(B) -2: G9001 manufactured by PS Japan (styrene / methacrylic acid copolymer, styrene / methacrylic acid = 92/8 (mass ratio), E ′ = 2600 MPa)
(B) -3: KSR-3A manufactured by Soken Chemical Co., Ltd. (crosslinked styrene polydisperse resin, average particle size = 3 μm, E ′ = 2500 MPa)
(B) -4: MR-2G manufactured by Soken Chemical Co., Ltd. (crosslinked PMMA particles, average particle size = 1 μm, E ′ = 2300 MPa)
(B) -5: Iupilon H4000 manufactured by Mitsubishi Engineering Plastics
(Polycarbonate resin, E ′ = 1800 MPa)
<Resin (X) other than resin (B)>
(X) -1: Novatec FY4 manufactured by Nippon Polypro Co., Ltd.
(Polypropylene, E ′ = 600 MPa)

<Inorganic fine particles (C)>
(C) -1: Titanium oxide A-1 manufactured by Sakai Chemical Co., Ltd. (anatase type titanium oxide, average particle diameter = 0.15 μm, refractive index = 2.52)

[Example 1]
(A) -1 and (b) -1 were mixed at a mass ratio of 97.5: 2.5 and extruded at 210 ° C. with a φ25 mm same-direction twin screw extruder to obtain an extruded sheet. Next, this extruded sheet was quenched with a casting roll at about 50 ° C. to obtain an unstretched sheet. The amount of molten resin discharged from the extruder and the line speed were adjusted so that the thickness of the unstretched sheet was approximately 400 μm on average.
The unstretched sheet was stretched successively 2.5 times in the longitudinal direction and 2.5 times in the width direction using a stretcher at a temperature of 80 ° C. (area magnification: 6.25 times), and then a heat treatment oven A film having a thickness of about 70 μm was produced by heat treatment at 140 ° C.
Table 1 shows the results of evaluation of the static friction coefficient, surface roughness, and rewinding phenomenon of the obtained film. For evaluation of the rewinding phenomenon and the like, a thin film was produced for convenience in each example.

[Examples 2-7, Comparative Examples 1-3]
The polylactic acid-based resin (A), resin (B) or resin (X) used in the mass ratio shown in Table 1 as shown in Table 1 (however, in Example 7, temperature conditions for heat treatment after stretching) In Comparative Example 1, only the polylactic acid resin (A) was used, and in Comparative Example 3, the heat treatment after stretching was not performed.) Film preparation and evaluation were performed. The results are shown in Table 1.

[Example 8]
A mixture of (a) -1, (b) -1 and (c) -1 at a mass ratio of 88.5: 2.5: 9 was used as the molding material for layer (I), and (a) -1 And (c) -1 were mixed at a mass ratio of 91: 9, and a co-extruded sheet was obtained using the same-direction twin screw extruder and multi-manifold die as a molding material for layer (II). At this time, the discharge amount of the molten resin was adjusted so that the thickness ratio of the layer (I) to the layer (II) was 9: 1.
Next, the coextruded sheet was quenched with a casting roll, and then stretched 2.5 times in the longitudinal direction and 3.0 times in the width direction using a stretcher (area). The laminate film was prepared by heat treatment at a temperature of 140 ° C. in a heat treatment oven.
The amount of molten resin discharged from the extruder and the line speed were adjusted so that the thickness of the laminated film after stretching and heat treatment was approximately 280 μm on average (250 μm for layer (I) and 30 μm for layer (II)).
Evaluation similar to Example 1 was performed about the obtained laminated | multilayer film. The results are shown in Table 1.

As is clear from Table 1, the film cutter of Comparative Example 1 using only the polylactic acid resin (A) has a large coefficient of static friction, a small surface roughness, and a problem of rewinding phenomenon. Further, even when the resin (B) is used, even in Comparative Example 2 in which the blending amount is small, the static friction coefficient is similarly large, the surface roughness is small, and there is a problem of the rewinding phenomenon. Further, in the comparative example 3 using the resin (X) whose storage elastic modulus (E ′) is outside the range of the present invention instead of the resin (B), the rewinding phenomenon cannot be prevented in the same manner.
On the other hand, if it is the film cutter of Examples 1-8 which mix | blended resin (B) of specific storage elastic modulus (E ') with the predetermined ratio with respect to polylactic acid-type resin (A), a static friction coefficient Can be controlled within a suitable range to increase the surface roughness and prevent the rewinding phenomenon.

1 film cutter 2 blades

Claims (6)

A film cutter having one or more layers mainly composed of a resin component composed of a polylactic acid resin (A) and a resin (B),
The storage elastic modulus (E ′) at 80 ° C. of the resin (B) is 700 MPa or more and 5000 MPa or less,
The ratio of resin (B) to a resin component is 0.5 mass% or more and 50 mass% or less, The film cutter characterized by the above-mentioned.   The film cutter according to claim 1, wherein the film cutter is stretched in at least one direction.   The resin (B) is one or more selected from polystyrene resins, acrylic resins, amorphous polyester resins, amorphous polyamide resins, and polycarbonate resins. The film cutter according to 1 or 2.   The film cutter according to claim 3, wherein the resin (B) is a polystyrene resin.   The film cutter according to any one of claims 1 to 4, wherein the coefficient of static friction with respect to the polyvinyl chloride resin wrap film measured according to JIS K7125 is 0.4 or more and 0.7 or less.   A storage box with a film cutter comprising the film cutter according to any one of claims 1 to 5.

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