JP2006193556A - Styrenic resin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a styrenic resin film having excellent high-speed mechanical processing suitability, adhesiveness and appearance characteristics with a slight environmental load. <P>SOLUTION: The styrenic resin film is characterized as follows. The styrenic resin film is composed of 0.01-2 pts.mass of fluorine particles having 1-10 μm volume-average particle diameter and 0.01-1 pt.mass of a 14-24C higher fatty acid salt and/or a 14-24C hydroxy-modified fatty acid salt as a dispersing agent thereof. The styrenic resin film has 0 to ±10 kV residual static electricity of at least one surface thereof. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a styrenic resin film that is excellent in low chargeability, transparency, and adhesiveness, and that is used for various packaging materials including envelope window materials, laminate materials for food packaging containers, and the like.

Styrenic resin films are excellent in transparency, rigidity, moldability, and the like, and thus are used in various packaging materials, food container laminates, and the like, including envelope window materials.
In the above applications, for the purpose of improving processability, corona discharge treatment, antistatic agent, and the like are generally coated (for example, JP-A Nos. 10-119978 and 2001-219939). ). However, in a styrene resin film using these known techniques, for example, in an envelope processing machine, the coating agent is deposited on a fixed roll and retransfers to the film, thereby causing a streaky appearance defect. There was a problem. Moreover, in the film product wound up in roll shape, since blocking between films generate | occur | produced and this tendency becomes strong toward a winding core, it could not be used to the film end.

On the other hand, as an uncoated styrene resin film (polystyrene non-coated film), for example, in JP-A-2-72051, styrene resin is used for the purpose of reducing film dust generated by friction in an envelope window processing step. A technique has been proposed in which fluorine-based particles made of polytetrafluoroethylene (PTFE) are added. However, the fluorine-based particles have a property that secondary aggregation easily occurs in melt extrusion, and the surface of the obtained film is It was difficult to obtain a good film in appearance such as roughening. For this reason, it was inadequate for various packaging material applications and food container laminate applications that require excellent appearance characteristics such as high transparency, gloss and smoothness. Further, in the envelope window processing, there is a problem that the bonding position of the film is shifted due to static electricity charged on the film.
As an invention using particles other than fluorine-based particles, a technique of adding inorganic particles made of regular aluminosilicate (Japanese Patent Laid-Open No. 2003-138038) is disclosed, but friction scratches with a suction cylinder in envelope window processing In addition, there is a problem that friction scratches with the envelope occur in the paper feeding process (single-function machine).

Japanese Patent Laid-Open No. 10-119978 JP 2001-219939 A JP-A-2-72051 JP 2003-138038 A

  The present invention provides a film satisfying the required characteristics required for applications such as envelope window materials, various packaging materials, and laminates for food containers in a styrene resin film, that is, an antistatic agent is coated on the film. Even if not, it is to supply a styrenic resin film that generates less charge in the secondary processing step, is excellent in high-speed processing suitability, and has excellent adhesion and appearance characteristics.

  As a result of intensive studies to achieve the above object, the present inventors have added specific particles to the styrenic resin, and set the residual static electricity level of the product to a specific range, so that in the subsequent secondary processing step. It has been found that there is an effect of suppressing the generated charging and charging due to peeling to an extremely low level. Also, by adding a specific dispersant at the same time as the particles, it has been found that the secondary agglomeration of the fluorine-based particles is prevented, and the excellent appearance characteristics of the styrene-based resin are maintained. Further, a specific thermoplastic elastomer is added. As a result of finding the effect of improving the adhesion by the addition, the present invention has been completed.

That is, the present invention is as follows.
1. A styrenic resin film comprising a styrenic resin, fluorine-based particles, and a fatty acid salt or / and a hydroxy-modified fatty acid salt as a dispersant, wherein the residual static electricity on at least one surface is 0 to ± 10 KV.
2. 1. Fluorine-based particles are added in an amount of 0.01 to 2 parts by mass with respect to 100 parts by mass of a styrene resin. The styrene resin film as described.
3. The volume average particle diameter of the fluorine-based particles is 1 to 10 μm. Or 2. The styrene resin film as described.
4). The dispersant is a C14-C24 higher fatty acid salt or / and a C14-C24 hydroxy-modified higher fatty acid salt, wherein 0.01 to 1 part by mass is added to 100 parts by mass of the styrene resin. 1. ~ 3. The styrene resin film according to any one of the above.
5. At least one component selected from styrene-based thermoplastic elastomer having a hydrophilic functional group, polyurethane-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, and polyester-based thermoplastic elastomer is 0 with respect to 100 parts by mass of the styrene-based resin. 1 to 10 parts by mass are added. ~ 4. The styrene resin film according to any one of the above.
6). The styrene-based resin is a resin in which 40% by mass or more of a styrene-based recycled material is mixed, and the melt index of the styrene-based recycled material is 1 to 10 g / 10 min. ~ 5. The styrene resin film according to any one of the above.
7). 1. The film is stretched uniaxially or more in the range of 0.1 to 5.4 MPa in the maximum heat shrinkage stress in the extrusion direction or the vertical direction of the film. ~ 6. The styrene resin film according to any one of the above.

  The styrenic resin film of the present invention can provide a film having low chargeability and excellent appearance characteristics by adding specific particles and a specific fatty acid salt. Moreover, the effect excellent in adhesiveness is acquired by adding a specific thermoplastic elastomer. Furthermore, the use of a specific recycled raw material as the styrene resin is effective in reducing the environmental burden and effectively using resources.

Hereinafter, preferred embodiments of the present invention will be described in detail.
In the present invention, fluorine particles and a fatty acid salt as a dispersant are added to a styrene resin, and the residual static electricity of the film after film formation is neutralized to a specific range. An effect (low chargeability) of suppressing charging generated in the next processing to a very low level is obtained.
That is, the fluorine-based particles used in the present invention are particles made of a fluorine-based polymer, such as vinylidene fluoride, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoroethylene, perfluoroethylene (alkyl vinyl ether). ) And other fluorine-containing vinyl monomers as essential components, and those obtained by polymerization using other vinyl polymer components such as ethylene and propylene as necessary are used alone. It may be a polymer or a copolymer.

The fluorine-based particles preferably used in the present invention is polytetrafluoroethylene (PTFE), and the addition amount of the fluorine-based particles is preferably 0.01 to 2 parts by mass with respect to 100 parts by mass of the styrene resin. A preferred range is 0.05 to 1 part by mass, more preferably 0.1 to 0.5 part by mass. By making the addition amount of the particles 0.01 parts by mass or more, an effect of suppressing charge generated in secondary processing such as envelope window processing is obtained, and by making it 2 parts by mass or less, practical transparency , Impact resistance, etc. can be maintained.
The particles preferably have a volume average particle diameter in the range of 1 to 10 μm, more preferably 2 to 8 μm, and still more preferably 2 to 6 μm. By setting the volume average particle diameter to 1 μm or more, it is possible to obtain the effects of suppressing the charge generated in the processing step and reducing the blocking property. Moreover, by setting it as 10 micrometers or less, roughening of the film surface is prevented and appearance characteristics, such as transparency and smoothness, are maintained. The volume average particle diameter is a value obtained using a laser diffraction particle size distribution analyzer.

In the fluorinated particles mixed with the styrene-based resin raw material, there is a problem in that the particles easily secondary agglomerate at the melt extrusion stage and the film surface becomes rough. For this reason, it has been very difficult to maintain the excellent transparency and smoothness that are characteristic of styrene-based resins.
As a result of examining various dispersion methods for this problem, the present inventors have found an effect of preventing secondary aggregation by using a specific fatty acid salt as a dispersant for fluorine-based particles.
That is, the fatty acid salt is preferably a C14 to C24 higher fatty acid salt or / and a C14 to C24 hydroxy-modified higher fatty acid salt. By selecting C14 or more in the compound, it is possible to make the dispersion of the fluorine-based particles more uniform. Moreover, film formation stability can be maintained by using C24 or less. Of these, stearates and 12-hydroxystearate are preferable. More preferably, an aluminum stearate and 12-hydroxy stearates are mentioned.

The aforementioned fatty acid salts can be used alone or in admixture of two or more. In this case, it is preferable to add 0.01 to 1 part by mass with respect to 100 parts by mass of the styrenic resin. Preferably it is 0.02-0.5 mass part, More preferably, it is 0.03-0.1 mass part. By making the fatty acid salt 0.01 parts by mass or more, it is possible to make the dispersion of the fluorine-based particles more uniform. Moreover, transparency (white turbidity) of a film and film forming stability become favorable by setting it as 1 mass part or less.
Styrenic resin films added with fluorine-based particles have a major feature in that they are less likely to be charged by friction or peeling, but in order to maximize this feature, residual static electricity at the film-forming stage is in a specific range. Found that it was necessary to remove.

  That is, the residual static electricity includes static electricity of a raw material (pellet) of styrene resin, static electricity generated by friction between pellets or a tube wall when the raw material is supplied, and shearing in melt extrusion. In contrast to these residual static electricity, fluorine-based particles do not have a decay (atmospheric discharge) action like surfactants with an antistatic function, so static electricity generated by various events accumulates in films immediately after production. High levels of static electricity will remain. When such a film was subjected to, for example, envelope window processing, it was found that the bonding position of the film might be shifted due to residual static electricity. Furthermore, when this problem was examined, it was found that misalignment can be prevented by setting the residual static electricity within a specific range.

That is, the range of residual static electricity for preventing displacement in envelope window processing is such that the residual static electricity on at least one surface of the film is within 0 to ± 10 KV, preferably within 0 to ± 5 KV, and more preferably 0 to ±±. Within 2 KV. Static electricity can be removed from the film by a known technique such as ion blow. Moreover, the residual static electricity was measured with a charged voltage measuring device (trade name “SK-030” / manufactured by Keyence Corporation) from the film wound up in a roll shape at a constant speed (see FIG. 2). .
In recent years, the speed of envelope window processing has been increasing year by year. However, in such a situation, the quality requirements for the film tend to be severer in order to accurately bond the film to a predetermined position.

In order to satisfy the above-mentioned strict requirements, the product of the present invention removes residual static electricity from the film to a specific range, and then suppresses electrification due to friction and peeling to a very low level even in high-speed machining by adding fluorine-based particles. Made it possible.
However, when performing envelope window processing at a high speed, the problem of skipping glue or the problem of poor adhesion often becomes a problem, which will be described in detail below.
Generally, an aqueous emulsion made of an ethylene-vinyl acetate copolymer is used as the main ingredient for the glue used in envelope window processing, but this is applied to a sponge-like stamp (gammer) placed on a metal rotating roll. After impregnation, it is applied to the envelope side or the film side, and the envelope and the film are adhered.

The glue skipping problem is a phenomenon in which the paste impregnated in the stamp is scattered by centrifugal force.If the processing speed increases, the centrifugal force also increases as the rotation speed of the gamma increases. In the case of scattering, the products are strongly bonded to each other, which may cause product defects. In order to prevent such problems, it is common to take measures such as reducing the amount of paste impregnated according to the processing speed.
However, since the amount of paste applied decreases by taking the above measures, sufficient adhesiveness may not be obtained depending on the type of paste. As a result of repeated studies on this problem, it has been found that the adhesiveness can be improved by adding a specific thermoplastic elastomer.

That is, examples of the specific thermoplastic elastomer include a styrene thermoplastic elastomer having a hydrophilic functional group, a polyester thermoplastic elastomer, a polyamide thermoplastic elastomer, and a polyurethane thermoplastic elastomer. Among these, a styrene thermoplastic elastomer having a hydrophilic functional group has a high effect on adhesiveness and can be suitably used.
The styrenic thermoplastic elastomer having a hydrophilic functional group is a styrene-ethylene-butylene-styrene copolymer (SEBS) or styrene-ethylene-propylene-styrene (SEPS) copolymer containing 10 to 60% by mass of a styrene monomer. Examples include polymers, styrene-butylene-butadiene (SBBS) copolymers, and the like, which is obtained by graft copolymerizing a carbonyl compound, a hydroxy compound, an epoxy compound, or the like with at least one component or more. To do. SEBS, SEPS, and SBBS are obtained by hydrogenating a styrene-butadiene-styrene copolymer (SBS) and a styrene-isoprene-styrene copolymer.

Among these, as carbonyl compounds, for example, those obtained by graft copolymerization of maleic anhydride to styrene thermoplastic elastomers are excellent in dispersibility with styrene resins, and this has a high effect on adhesiveness. It can be suitably used.
In order to improve the adhesiveness by adding the thermoplastic elastomer to the styrene resin, it is preferable to add 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass with respect to 100 parts by mass of the styrene resin. Part by mass, more preferably 0.5 to 3 parts by mass. By adding 0.1 parts by mass or more, it is a range for expressing practical adhesive strength (for example, adhesive force that does not cause film peeling in the high-speed automatic sealing and sealing process after envelope processing). By making it below, it is possible to maintain the transparency required for the film.

According to these inventions, in envelope window processing, it is possible to bond a film accurately at a predetermined position even at a high speed processing of 500 sheets / min or more, and there is a problem such as peeling in a subsequent process after film bonding. Stable machining is possible without causing it.
Next, the styrene resin constituted in the present invention will be described.
The styrene resin used in the present invention is a homopolymer composed of a styrene monomer and / or a copolymer containing 50% by mass or more of a styrene monomer, Examples include styrene and alkyl styrene such as α-methyl styrene, p-methyl styrene, and t-butyl styrene. Further, styrene copolymers include styrene- (meth) acrylic acid ester copolymers, styrene-acid anhydride copolymers, styrene-methacrylic acid copolymers, styrene-butadiene-styrene copolymers, styrene. -In addition to butadiene-isoprene-styrene copolymer, styrene-isoprene copolymer, and the like, thermoplastic resins such as impact-resistant polystyrene (HIPS) made of core-shell type and / or salami-structured rubber particles, These may be used alone or as a mixture of two or more.

Furthermore, it is also possible to mix a styrene-based thermoplastic elastomer (SEBS, SEPS) containing 20 to 60% by mass of a styrene monomer into the styrene-based resin, and the mixing ratio is within a range that does not impair transparency. 0 to 20% by mass can be added.
Among these styrenic resins, general-purpose polystyrene (GPPS) and / or styrenic recycled materials are preferable from the viewpoints of rigidity and transparency.
The GPPS is preferably a resin having a weight average molecular weight measured by GPC of 160,000 to 500,000, more preferably 180,000 to 400,000. By setting the molecular weight to 160,000 or more, it is possible to provide film formation stability and a sufficient degree of orientation, and by setting the molecular weight to 500,000 or less, it is possible to provide the fluidity of the resin necessary for melt extrusion.

In addition, the styrene-based recycled raw material is a waste generated when a product such as a styrene-based resin sheet and / or a film is supplied to the market, for example, subjected to secondary processing such as a lid for a lunch box, an envelope window, After separation and collection, the raw material is re-pelletized through at least one thermal history.
In this styrene-based recycled raw material, molecular weight reduction, oligomer formation, and oxidative degradation have progressed due to the thermal history due to re-pelletization, and using such raw materials to obtain a film can improve film formation stability and It was extremely difficult in terms of ensuring quality.
As a result of intensive studies on this problem, it has been confirmed that the stability and quality of film formation can be ensured by using a resin having a specific MI (melt index) value for the styrene-based recycled raw material. I found it.

That is, the MI value preferably used as the styrene-based recycled raw material is 1 to 10 g / 10 min, more preferably 1.5 to 8 g / 10 min. By reducing the MI value to 1 g / 10 min or more, the outflow of thermal decomposition products (carbon, gel) during melt extrusion is reduced to a practical level, and vapor leaked from the die adheres to the wall surface, and then aggregates and drops. The effect of reducing film contamination by doing is acquired. Moreover, it is possible to make film forming stability and thickness distribution small by setting it as 10 g / 10min or less. In addition, the said MI value is a value measured based on ASTMD-1238 (200 degreeC, 49N).
About the mixing ratio of the styrene-type reproduction | regeneration raw material in this invention, 40-90 mass% of the whole film is preferable from a viewpoint of reduction of environmental impact, effective utilization of resources, and film forming stability, More preferably, it is 50-80 mass%. It is.

Next, the film manufacturing method and its characteristics will be described.
The styrenic resin film of the present invention is uniaxial or more stretched, and its production method is uniaxial or sequential biaxially stretched film obtained by roll stretching method and / or tenter method after melt extrusion, uniaxial by inflation method or The biaxially stretched film is produced by a known technique such as a simultaneous biaxially stretched film, but is particularly preferably a biaxially stretched film having a maximum heat shrinkage stress value of 0.1 to 5.4 MPa in at least a uniaxial direction in the extrusion direction or its vertical direction More preferably, it is 0.3-5.0 MPa, More preferably, it is 0.7-4.0 MPa. This value is a characteristic value mainly determined by the draw ratio and the draw temperature, and affects the formation of protrusions by fluorine-based particles on the film surface and the cutability during envelope processing. In other words, by setting the maximum heat shrinkage stress value to 0.1 MPa or more, the projections of fluorine-based particles are appropriately formed on the film surface, and the effect of reducing static electricity due to friction and peeling in the film processing step and the tear strength are By making it smaller, the cutting performance in the envelope processing machine is also improved. Moreover, by setting it as 5.4 Mpa or less, it is possible to suppress the light scattering (transparency fall) which arises when a space | gap expands at the interface of a fluorine-type particle and a styrene resin (base material). The maximum heat shrinkage stress value is the maximum shrinkage stress obtained by dipping in a 120 ° C. (Tg + 15 ° C.) silicone oil bath. Measured according to ASTM D-1504.

Furthermore, although there is no restriction | limiting in particular about the thickness of the styrene resin film of this invention, Generally it becomes like this. Preferably it is 5-100 micrometers, More preferably, it is 10-80 micrometers, More preferably, it is 20-50 micrometers. This range is a range determined by workability for handling by an operator and machine suitability such as an envelope processing machine.
Hereinafter, an Example and a comparative example are explained in full detail. In each test, a determination of “◯” or more is a standard required for practical use.

[Film Production Example 1]
Extruder (screw: Dalmage 5) obtained by dry blending GPPS (trade name “PSJ polystyrene” # 685 / manufactured by PS Japan Co., Ltd.) with fluorine-based particles listed in Tables 1 and 2, a dispersant and a thermoplastic elastomer. Piece, L / D = 29, manufactured by Mitsubishi Heavy Industries, Ltd.), and the molten sheet flowing out from the T-die is longitudinally stretched by a roll stretching machine (roll set temperature = 125 ° C., magnification = 1.8). Then, the film was stretched laterally (oven setting temperature = 134 ° C., magnification 4 times) with a tenter to obtain a film having a thickness of 25 μm.

[Film Production Example 2]
It is melt-kneaded in an extruder equipped with a circular die (bent screw, L / D = 28, manufactured by Nippon Steel Works), and simultaneously biaxially stretched (length 6.5 times, width 5) by the inflation method. And a film having a thickness of 25 μm was formed. At this time, a predetermined amount of the fluorine-based particles and the dispersant was air-pumped from an independent table feeder, supplied to the extruder hopper, and melt-kneaded with the polystyrene-based resin in the extruder.

[Chargeability test]
Evaluation of the chargeability of the film was carried out by producing a chargeability test apparatus as shown in FIG. The device has one metal fixing roll (Φ30 mm, stainless steel roll), one metal roll (Φ25, stainless steel roll) for controlling the film tension, and a rubber motor for controlling the running speed. One roll (Φ60, made of isoprene) and three free rolls (Φ50, SUS roll) are arranged. As a sample, a 100 mm wide × 1200 mm long film was attached to this test apparatus (see FIG. 1), and in advance by an ion blow type electric machine (trade name “KD-410” / manufactured by Kasuga Electric Co., Ltd.) before the test. The static electricity of the film was neutralized to 0 to ± 0.3 KV.
In the test, the metal roll for film tension control was adjusted with a low friction air cylinder (φ25mm cylinder x 2 units) so that the tension = 20N, and the rubber motor roll was driven for 3 minutes at a speed = 20m / min. I let you. At this time, the film surface is repeatedly peeled and rubbed by each roll, and gradually accumulates static electricity. This is measured by a charged voltage measuring device (trade name “SK−”) disposed at one place of the apparatus (see FIG. 1). 030 "/ manufactured by Keyence Co., Ltd.) at a distance of 5 cm from the film and measured at 500 ms (millisecond) intervals.

The same test was repeated three times on the same sample, and each measurement data was subjected to a 10-point moving average process, and then the average voltage after 3 minutes was obtained. The chargeability was evaluated according to the following criteria. The test atmosphere at this time is 23 ° C. × 20% RH.
×: +10.1 KV or more, or −10.1 KV or less Δ: +5.1 to +10 KV, or −5.1 to −10 KV
○: +2.1 to 5.0 KV, or −2.1 to −5 KV
A: 0 to +2 KV or 0 to -2 KV

[Residual static electricity]
Static electricity remaining on the surface of the film was drawn out from the film wound up in a roll shape at a constant speed, and measured with a charged voltage measuring device (trade name “SK-030” / manufactured by Keyence Corporation) (see FIG. 2). ). The measurement conditions at this time are a film drawing speed of 5 m / min, a measurement length of 30 m, a measurement distance between the film and the charged voltage measuring device of 5 cm, and a measurement interval of 500 ms. Moreover, the charged voltage of the film was evaluated according to the following criteria, with the maximum value of the measured value as the representative value of the sample. The measurement is performed in an environment that is not affected by surrounding static electricity and does not discharge static electricity charged on the film.
×: +20.1 KV or more, or −20.1 KV or less Δ: +10.1 KV to +20.0 KV, or −10.1 to −20.0 KV
○: +5.1 to +10 KV, or −5.1 to −10 KV
A: 0 to +5 KV, or 0 to -5 KV

[Heat shrinkage stress]
The heat shrinkage stress was determined from the peak value of the shrinkage stress measured by immersion in a 120 ° C. silicone oil bath. (Conforms to ASTM D-1504)
[Dispersibility]
Using an actual microscope, it was magnified and observed at 20 times, and evaluated according to the following criteria.
X: Two or more aggregated particles are present in 50% or more of the total particles.
Δ: Two or more aggregated particles are present at 30% or more and less than 50% of the total particle.
A: Two or more aggregated particles are present at 10% or more and less than 30% of the total particle.
A: Two or more aggregated particles are less than 10% of the whole particles.
[Melt index]
Measurement was performed in accordance with ASTM D-1238 (200 ° C., 49 N / G condition).

[Static electricity during envelope processing]
Static electricity was evaluated when window processing was performed at a film processing speed of 600 sheets / min (film speed of 40.8 m / min) in a high-speed envelope processing machine (trade name “Helios” 627GSV / WINKLER + DUNNEBIER). For static electricity, as shown in FIG. 3, a voltage measuring device (trade name “KSD-0103” / manufactured by Kasuga Electric Co., Ltd.) is installed at a position before the film passes through multiple rolls and is processed into windows. (Distance with film 100 mm) and measured. Judgment criteria are as follows.
×: +20.1 KV or more, or −20.1 KV or less Δ: +10.1 KV to +20.0 KV, or −10.1 to −20.0 KV
○: +5.1 to +10 KV, or −5.1 to −10 KV
A: 0 to +5 KV, or 0 to -5 KV

[Position shift during envelope processing]
After carrying out the above-mentioned high-speed envelope processing, the positional deviation was evaluated by removing 50 envelopes and shifting the number of sheets by 1 mm or more from the predetermined position with respect to the film flow direction. The predetermined position for bonding refers to a bonding position when positioning at low speed, and was evaluated according to the following criteria.
×: 5 or more △: 3 or more, less than 5 ○: 1 or more, less than 3 (However, do not exceed 2 mm.
◎: 0 sheets

[Adhesiveness]
After carrying out the high-speed envelope processing machine, the evaluation of adhesiveness was made by peeling off the film 10 minutes after the completion of bag making, and judging according to the following criteria. The window paste used at this time was “trade name: JW-7346-U9” (manufactured by Nippon Fuller), and craft paper (white, waste paper = 70%) was used as the envelope material.
X: The material destruction of an envelope does not occur at all.
(Triangle | delta): The material destruction of an envelope generate | occur | produces 1 to 50% of an adhesion surface.
○: Material destruction of the envelope occurs 51 to 90% of the adhesive surface.
(Double-circle): The material destruction of an envelope generate | occur | produces 91-100% of an adhesion surface.

[Examples 1 to 3]
Examples 1 to 3 are films to which fluorine-based particles having a volume average particle diameter of 2 to 10 μm were added under the conditions of [Film Production Example 1] (Table 1). In the film containing fluorine-based particles, the charge voltage was maintained at a very low level in the [Chargeability test] by performing the static elimination treatment once, and showed low chargeability. The difference in chargeability due to the difference in average particle diameter was slight.

[Comparative Examples 1-3]
Comparative Examples 1 to 3 in Table 1 are films obtained under the same conditions as described above. Comparative Example 1 is a case where particles are not added, Comparative Example 2 is a case where spherical aluminosilicate is added, and Comparative Example 3 is a spherical silicone. This is a case where resin particles are added (Table 1). In these cases, all were inferior to the fluorine particle-added films (Examples 1 to 3) in [Chargeability test].

[Examples 4 to 7]
In Examples 4 to 7, zinc stearate (C18), magnesium stearate (C18), magnesium 1,2-hydroxystearate (C18), and aluminum stearate (C18) were used as the dispersant under the same conditions as described above. These are films obtained by mixing with fluorine-based particles (Table 2). All of these had good dispersibility of the fluorine-based particles, and were excellent in transparency and smoothness.

[Comparative Example 4]
Comparative Example 4 is a film in which only fluorine-based particles are added without adding a dispersant under the same conditions as described above (Table 2). In this case, the secondary aggregation of the fluorine-based particles was significant, and the film surface was roughened.

[Comparative Examples 5 and 6]
In Comparative Examples 5 and 6, zinc laurate (C12) and zinc t-butylbenzoate were used in combination with fluorine particles under the same conditions as described above (Table 2). Even in these cases, the dispersion of the fluorine-based particles was insufficient and the appearance characteristics were impaired.

[Example 8]
Example 8 is a film obtained by adding fluorine particles and magnesium stearate according to [Film Production Example 2] (Table 3). Since the static electricity was removed by ion blow in the pre-product stage, almost no static electricity was generated during the processing of the envelope window, and no displacement occurred.

[Examples 9 and 10]
Examples 9 and 10 were performed under the same conditions as in Example 8 except that impact polystyrene (HIPS) was mixed and polystyrene recycled raw materials were mixed (Table 3). In any case, as in Example 8, good results were obtained.

[Examples 11 and 12]
Examples 11 and 12 in Table 3 were carried out under the same conditions as in Example 8 except that a specific thermoplastic elastomer was added (Table 3). In any case, the adhesiveness after processing the envelope window was extremely good.

[Comparative Example 7]
Comparative Example 7 in Table 3 was performed under the same conditions as in Example 8 except that the charge removal process by ion blow was not performed (Table 3). In this case, since the static elimination treatment was not performed, the position shift occurred due to residual static electricity.
As is clear from the above results, the film added with fluorine-based particles and a specific dispersant maintains good appearance characteristics, and by removing the static electricity to a specific range, it can be used for subsequent friction and peeling. On the other hand, the chargeability is extremely low. Furthermore, by adding a specific thermoplastic elastomer, a higher degree of adhesion can be obtained.

  The styrenic resin film of the present invention has excellent appearance characteristics and low chargeability, so it is excellent in machinability and suitable for various packaging materials, envelope window materials, food packaging laminate materials, and the like. .

The chargeability test apparatus (schematic diagram) used for the evaluation of film chargeability is shown. The residual static electricity measuring method (schematic diagram) of a film is shown. The window processing process (schematic diagram) of the high-speed envelope processing machine used for the evaluation of the envelope processing suitability (residual static electricity and misalignment) is shown.

Claims (7)

  A styrenic resin film comprising a styrenic resin, fluorine-based particles, and a fatty acid salt or / and a hydroxy-modified fatty acid salt as a dispersant, wherein the residual static electricity on at least one surface is 0 to ± 10 KV.   The styrene resin film according to claim 1, wherein 0.01 to 2 parts by mass of fluorine-based particles are added to 100 parts by mass of the styrene resin.   3. The styrene resin film according to claim 1, wherein the volume average particle diameter of the fluorine particles is 1 to 10 [mu] m.   The dispersant is a C14-C24 higher fatty acid salt or / and a C14-C24 hydroxy-modified higher fatty acid salt, wherein 0.01 to 1 part by mass is added to 100 parts by mass of the styrene resin. The styrenic resin film according to any one of claims 1 to 3.   At least one component selected from styrene-based thermoplastic elastomer having a hydrophilic functional group, polyurethane-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, and polyester-based thermoplastic elastomer is 0 with respect to 100 parts by mass of the styrene-based resin. The styrene resin film according to any one of claims 1 to 4, wherein 1 to 10 parts by mass are added.   The styrene-based resin is a resin in which 40% by mass or more of a styrene-based recycled raw material is mixed, and the melt index of the styrene-based recycled raw material is 1 to 10 g / 10 min. The styrene resin film as described.   The styrenic resin film according to any one of claims 1 to 6, wherein the film is stretched uniaxially or more in the range of 0.1 to 5.4 MPa in the maximum heat shrinkage stress in the extrusion direction or in the vertical direction of the film. .

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