JP5414603B2 - Multi-layer sheet for packing filter tow bale - Google Patents

Description

  The present invention relates to a multilayer sheet for packing a filter tow bale and a method for packing a filter tow bale using the multilayer sheet.

A filamentous body, a tow, a filament, etc. have a low bulk density. For example, a filter tow made of cellulose acetate filament has a small bulk density of about 100 kg / m ^3, and in consideration of transportation efficiency and lateral handling when processing into a cigarette filter, it is necessary to apply a press or the like during packing. Compressed by high pressure by the pressure means, the bulk density is increased to 300 to 600 kg / m ³ and packed. Such a package is called a bale (toe bale).

Thus the press compaction pressure of highly compressed bale can be up to reach a 5000kPa (500t / m ^2), even though when the compression pressure is low, it is not less than 1000kPa (100t / m ^2). For this reason, a rebound internal pressure of 20 kPa to 400 kPa remains in the packed filter tow due to stress repelling compression. In order to obtain a package that can withstand such a repulsive internal pressure, the filter tow has been conventionally bundled with bands made of metal such as iron or plastic (referred to as “binding bands”).

  In the conventional technique, in an ordinary packing body, the packing material for the abdomen and the packing material for the ceiling or the bottom are integrated by a binding band. As a result, the tow veil can be prevented from rupturing, but with the expansion of the tow veil, only the portion other than the portion of the binding band that cannot expand is swollen.

  As a result, the binding band bites into the surface layer of the tow veil and the tow veil is constricted. In the constricted portion, the tow bale is partially compressed with a high pressure. Therefore, when the filter tow is taken out from the tow bail as a continuous filament, the filter tow may break at that portion. Further, it is necessary to cut the binding band at the time of unpacking. However, since the binding band cut at this time flies off, there is a risk of injury to the operator. For this reason, the packaging form which omits a binding band has been examined.

  For example, DE 76-U35849 (Patent Document 1) discloses a laminate sheet of polypropylene and paper in which a compressed filter tow (press bale) is vapor-deposited with aluminum on the inside in order to improve the problem of filter tow binding due to these bands. And a packaging body in which the outside is wrapped with cardboard bonded with a solvent-type adhesive (specifically, a solvent-type adhesive of chloroprene rubber).

  Japanese Patent Application Laid-Open No. 7-215338 (Patent Document 2) discloses a technique for joining the upper part and the central part of the collection container using a hook-and-loop fastener tape and no adhesive. This technology includes several upright side parts that surround and demarcate the outer periphery of the collection container, and these side parts can withstand repulsive internal pressure without a binding band. Yes.

  On the other hand, since it is such a form, since a side part is calculated | required to have the rigidity and intensity | strength which can bear the repulsion internal pressure of a collection container, a packaging form becomes large and the cost is also high. For this reason, these packing bodies can be used only within a range in which the packing material can be collected and reused.

  Japanese National Patent Publication No. 9-508880 (Patent Document 3) discloses sealed packaging with three plastic sheets of a top portion, a bottom portion, and a trunk portion or a packaging material section made of a sheet. In this packaging method, the packaging material sections are overlapped with each other and placed on the bale and bonded together by adhesion and / or welding.

  As the packaging material section, a multilayer sheet made of a polyethylene sheet is disclosed as a plastic sheet or a sheet.

  As a particularly advantageous embodiment, it is described that a stripe or point-like bond is formed which has a very high shear strength but can be easily peeled off and dissociated by hand or machine on the other side.

  When such a stripe or dot-like joining is performed, the veil cannot be completely sealed, and it is affected by the outside air, and the problem of moisture prevention particularly in a high humidity environment cannot be solved.

  Furthermore, in order to perform striped or spot-like joining, there is no choice but to heat seal. In heat sealing, since the seal bar is always kept at a high temperature at which heat sealing is possible, there is a risk of burns if an operator accidentally contacts the exposed heat sealing bar.

  Originally, an impulse seal that returns to almost normal temperature immediately after heat sealing or a high-frequency seal that does not reach high temperatures is preferable for the safety of the packaging operator. Such a safe sealing method could not be adopted.

  Japanese Patent Application Laid-Open No. 2010-6379 (Patent Document 4) relates to a packing method and a packing body for a compressed packing body of filter tow, and discloses a sealed packing with two plastic sheets or sheets on the top and bottom. Has been.

  In this document, a PE / EVA / PE multilayer sheet having a polyethylene (PE) outer layer and an ethylene vinyl acetate copolymer (EVA) as a central layer, polyamide (PA ) Is a multilayer sheet of PE / PA / PE.

DE 76-U35849 JP-A-7-215338 Japanese National Patent Publication No. 9-508880 Japanese Patent Laid-Open No. 22-6379

  As described above, the filter tow covered with the packing material without using the binding band solves the problem of the binding band biting into the filter tow and the problem of ensuring the safety of the worker when cutting the binding band. Has been.

  However, when a cutting tool such as a cutter is used when opening the packing material, the product filter tow may be damaged. For this reason, it is desirable that the operator can easily open it by hand without using a cutting tool (having easy peel properties), but the above-described conventional technology has room for improvement in terms of the easy peel properties. .

  Moreover, when it is the multilayer structure which consists of a different material like patent document 4, even when collect | recovering after use, there is no choice but to reuse as a fuel.

  INDUSTRIAL APPLICABILITY The present invention can be recycled as a production raw material for the same application, has a sealing property and an easy peel property, and has a good packing property and unpacking workability. It is an object to provide a multilayered sheet and a method for packing a filter tow veil using them.

As a means for solving the problems, the present invention provides:
A multilayer sheet for packing a filter tow veil,
The multilayer sheet has a base material layer (A), an intermediate layer (B) and a seal layer (C),
The density range of 20 to 80% by mass of linear low density polyethylene (mLLDPE) having a density of 0.91 to 0.93, in which the base layer (A) and the seal layer (C) are polymerized using a metallocene catalyst. Of low density polyethylene (LDPE) of 80-20% by mass,
The intermediate layer (B) is composed of 20 to 80% by mass of mLLDPE having a density of 0.90 to 0.92 and 80 to 20% by mass of LDPE,
The density of mLLDPE forming the base layer (A) and the sealing layer (C) is higher than the density of mLLDPE forming the intermediate layer (B),
Provided is a multilayer sheet for packaging a filter tow veil having an overall thickness of 90 to 300 μm.

Furthermore, the present invention provides a solution to other problems.
Cutting the multilayer sheet according to claim 1 or 2 into a square or a rectangle;
The step of obtaining a bag-shaped multilayer sheet by joining the multilayer sheet cut into the square or rectangular shape in two in the transverse direction (TD) during sheet molding, and then joining both ends in the longitudinal direction (MD) during sheet molding;
The step of covering from one side of the filter tow veil with the bag-shaped multilayer sheet serving as the upper sheet,
The step of covering from the other side with the bag-shaped multilayer sheet or the multilayer sheet according to claim 1, which becomes a lower sheet,
Heat-sealing in a state where the upper sheet and the lower sheet are joined together,
A method for packing a filter tow veil having

  The multilayer sheet for packing the filter tow veil according to the present invention is less susceptible to damage and pinholes during bending work and storage and transportation of the tow bale, so that the work efficiency of the packing is improved and the airtightness of the packing is maintained. Further, when the filter tow veil is opened by hand after packing, the workability is improved because it can be easily torn. Furthermore, since all the plastics blended in the multilayer sheet are polyethylene, materials other than solid fuel can be recycled.

Explanatory drawing of the manufacturing method of the bag-shaped multilayer sheet of this invention. Explanatory drawing of the packing method of the filter tow veil by the well-known packing apparatus using the bag-shaped multilayer sheet and multilayer sheet of this invention. Explanatory drawing of the attachment state to the packing apparatus of the bag-shaped multilayer sheet and multilayer sheet in FIG. Explanatory drawing of the packing method of the filter toe veil by the well-known packing apparatus using two bag-shaped multilayer sheets of this invention. Explanatory drawing of the attachment state to the packing apparatus of the two bag-shaped multilayer sheets in FIG.

<Multilayer sheet for packing filter tow bale>
[Base material layer (A)]
The base material layer (A) is a layer composed of mLLDPE and LDPE.

  mLLDPE is a linear low density polyethylene obtained by copolymerizing a metallocene catalyst of an organometallic complex as a polymerization catalyst and copolymerizing ethylene and an α-olefin such as 1-butene or 1-hexene. LDPE is a radical polymerization or anion. Low density polyethylene produced by polymerization or the like, all having a density in the range of 0.91 to 0.93.

  If the density is less than 0.91, the surface of the multilayer sheet becomes soft, and the multilayer sheet is deformed or damaged when the package is transported by a transporting device such as a conveyor, so that airtightness during packaging cannot be maintained.

  If the density exceeds 0.93, the surface of the multilayer sheet becomes hard, and cracks and pinholes occur in the process of folding the multilayer sheet on the base of the bale compression device and in the process of expanding from the folded state. It becomes impossible to keep airtight.

  The ratio of mLLDPE and LDPE in the base material layer (A) is 20 to 80% by mass, preferably 30 to 70% by mass for LDLDPE, and 80 to 20% by mass, preferably 70 to 30% by mass for LDPE. .

  When the ratio of mLLDPE is higher than 80% by mass, the tear strength increases, and when the filter tow bale is packed, it is difficult for the operator to open the package by hand. Further, it is difficult to form the sheet. For example, when the sheet is inflated with an inflation device, if the discharge speed is increased, a fracture occurs, so that the production speed cannot be increased, resulting in a problem that the sheet processing cost increases.

  If the ratio of mLLDPE is lower than 20% by mass, the strength of the multilayer sheet will be reduced, the multilayer sheet will not be able to withstand bending, cracks and pinholes will be generated, and the package cannot be kept airtight.

  The base material layer (A) can be composed of two layers or three or more layers for the purpose of imparting strength. When the number of base layers is two or more, the content ratio of mLLDPE and LDPE may be the same in all layers as long as it is within the above range, or may be different for each layer.

[Intermediate layer (B)]
The base material layer (A) is a layer composed of mLLDPE and LDPE.

  Both mLLDPE and LDPE have a density in the range of 0.90 to 0.92.

  When the density is less than 0.900, polyethylene cannot maintain proper crystallinity, and when the multilayer sheet is folded, the multilayer sheet itself is plastically deformed and cannot be restored.

  When the density exceeds 0.92, the surface of the multilayer sheet becomes hard, and cracks and pinholes are generated in the process of folding the multilayer sheet on the base of the bale compression device and the process of unfolding from the folded state. I can't keep her airtight later.

  The ratio of mLLDPE and LDPE in the intermediate layer (B) is 20 to 80% by mass, preferably 30 to 70% by mass for mLLDPE, and 80 to 20% by mass, preferably 70 to 30% by mass for LDPE.

  When the ratio of mLLDPE is higher than 80% by mass, it is difficult to form a sheet. For example, if the discharge speed is increased when the sheet is inflated with an inflation device, the production speed cannot be increased due to the occurrence of fracturing. To do.

  If the ratio of mLLDPE is lower than 20% by mass, the flexibility and strength of the multilayer sheet will be reduced, the multilayer sheet will not be able to withstand bending, cracks and pinholes will be generated, and the package cannot be kept airtight.

  If necessary, an adhesive layer may be sandwiched between the base material layer (A) and the intermediate layer (B) for the purpose of adhesion. The material of the adhesive layer is polyethylene from the viewpoint of recycling, preferably mLLDPE, LDPE or a mixture thereof. The thickness of the adhesive layer is preferably 10 μm or less.

[Seal layer (C)]
The seal layer (C) is a layer composed of mLLDPE and LDPE.

  Both mLLDPE and LDPE have a density in the range of 0.91 to 0.93.

  If the density is less than 0.91, the sealing surface of the multilayer sheet becomes soft, and the filter tow sprinkled into the filling container (filling can) is compressed by the base of the bale compression device in which the multilayer sheet is folded. When the sealing surface of the sheet comes into contact with the inner surface of the filling container, the multilayer sheet is deformed or dropped from the base of the bale compression device.

  When the density exceeds 0.93, the sealing surface of the multilayer sheet becomes hard, and the process of folding the multilayer sheet on the base of the bale compression device or the process of feeding out the bag folded on the base of the bale compression device after compressing the filter tow The multilayer sheet cannot withstand bending and cracks and pinholes occur, making it impossible to keep the package airtight.

  The ratio of mLLDPE to LDPE in the seal layer (C) is 20 to 80% by mass, preferably 30 to 70% by mass for mLLDPE, and 80 to 20% by mass, preferably 70 to 30% by mass for LDPE.

  When the ratio of mLLDPE is higher than 80% by mass, the tearing strength is increased and it is difficult for the operator to open the package by hand. Further, it is difficult to form the sheet. For example, when the sheet is inflated with an inflation apparatus, if the discharge speed is increased, a fracture occurs, so that the production speed cannot be increased, and there is a problem that the sheet forming cost increases.

  If the ratio of mLLDPE is lower than 20% by mass, the strength of the multilayer sheet will be reduced, the multilayer sheet will not be able to withstand bending, cracks and pinholes will occur, and the package cannot be kept airtight.

  If necessary, an adhesive layer may be sandwiched between the intermediate layer (B) and the seal layer (C) for the purpose of adhesion. The material of the adhesive layer is polyethylene from the viewpoint of recycling, and is mLLDPE, LDPE or a mixture thereof. The thickness of the adhesive layer is preferably 10 μm or less.

  The density of mLLDPE forming the base layer (A) and the sealing layer (C) is higher than the density of mLLDPE forming the intermediate layer (B).

  The total thickness of the multilayer sheet is preferably 90 to 300 μm, more preferably 100 to 180 μm, and still more preferably 120 to 165 μm.

  In the multilayer sheet, each of the base material layer (A), the intermediate layer (B), and the sealing layer (C) has a thickness of 30 to 100 μm, preferably 30 to 60 μm, and more preferably 40 to 55 μm. Although it is preferable that all layer thickness is also comparable, it can also differ in the range of the said total thickness.

  The multilayer sheet of the present invention has an Elmendorf tear strength in the machine direction (MD) of 100 N / mm or less during sheet molding within the above thickness range, and can be easily torn to the MD side by an operator's hand. it can.

  In the multilayer sheet of the present invention, since the base layer (A), the intermediate layer (B), and the seal layer (C) are all made of polyethylene, the same multilayer sheet for packing the filter tow bale after use. Can be recycled for use.

  The multilayer sheet of the present invention is produced by co-extrusion of a base material layer, an intermediate layer and a seal layer, and a film to be an intermediate layer and a film to be a seal layer are welded or fused together to a film to be a base material layer. It can be manufactured by applying a method for forming a film, a film serving as a base layer, a film serving as an intermediate layer, and a film serving as a seal layer through an adhesive.

<Bag-shaped multilayer sheet>
The manufacturing method of the bag-shaped multilayer sheet 10 using the multilayer sheet 1 will be described step by step with reference to FIGS.

  (A) The process has shown the top view of the multilayer sheet 1 cut | disconnected by square thru | or a rectangle. In the figure, MD is an extrusion direction during sheet extrusion, and TD is a direction orthogonal thereto. The opposite sides are indicated as side 2 and side 3.

  In the step (b), the multilayer sheet 1 is folded in the TD direction. That is, the side 2 is folded in half.

  In the step (c), the inner surfaces of the sides 2 (2a, 2b) when folded in two in the step (b) are heat-sealed and joined (seal portions 5a, 5b). At this time, an opening 6 is formed.

  In step (d), in the state of step (c), the opening 6 is expanded in the width direction, and the central portion 7 is depressed, and the seal portions 5a and 5b are further deformed into a substantially triangular shape as shown in the figure. Let

  Further, as shown in step (e), the substantially triangular protrusions 8a and 8b are folded into a bag shape.

  Thus, the bag-shaped multilayer sheet 10 is obtained. The bag-shaped multilayer sheet 10 has no gap other than the opening 6, and the inside becomes a space for accommodating the filter tow veil.

  A known heater bar, impulse heater, high frequency welding, ultrasonic sealer, or the like can be used for heat sealing.

<Packing method for filter tow veil>
2 and 3, an embodiment of a known packing device (for example, refer to WO02 / 32,238 A2) filter toe bale packing method will be described. The packing method of FIG. 2 is an embodiment using a planar multilayer sheet 1 (see step (a) in FIG. 1) and a bag-like multilayer sheet 10 (see step (e) in FIG. 1).

  The filter tow 30 before compression molding is placed in a packing device including a filling can 20, a combination of the lower base 21 and the hydraulic rod 25, and a combination of the upper base 22 and the hydraulic rod 26.

  At this time, the multilayer sheet 1 is disposed on the lower base 21, and the bag-shaped multilayer sheet 10 is disposed on the upper base 22. These may be reversed.

  The bag-shaped multilayer sheet 10 covers the upper base 22 from the bottom surface 11 and is folded back so that the opening 6 surrounds the hydraulic rod 26, and the side surface 12 is folded to the back side of the lower base 22.

  By pressing from above and below in this state, the filter tow is compressed to form a tow veil.

  Thereafter, with the filling can 20 moved either up or down, the bag-shaped multilayer sheet 10 covers the filter tow veil from above, and the multilayer sheet 1 further exposes the portion where the filter tow veil is exposed from below. cover.

  Next, heat sealing is performed in a state where the portions to be joined of the bag-shaped multilayer sheet 10 and the multilayer sheet 1 are overlapped. A known heater bar, impulse heater, high frequency welding, ultrasonic sealer, or the like can be used for heat sealing.

  When the multilayer sheet 1 and the bag-shaped multilayer sheet 10 are attached to the lower base 21 and the upper base 22 as shown in FIG. 2, they are attached so that their MDs coincide with each other as shown in FIG. For this reason, the package after heat-sealing the multilayer sheet 1 and the bag-shaped multilayer sheet 10 (one in which the multilayer sheet 1 and the bag-shaped multilayer sheet 10 are integrated) has the same MD, so MD) side is easy to tear.

  In particular, since the multilayer sheet 1 and the bag-shaped multilayer sheet 10 have a tearing strength in the machine direction (MD) of 100 N / mm or less, the operator can manually seal the sealing portion between the bag-shaped multilayer sheet 10 and the flat multilayer sheet 1. Can be opened easily by pulling.

  Next, another embodiment of the filter toe bale packing method will be described with reference to FIGS. The packing method of FIG. 4 is an embodiment using two bag-shaped multilayer sheets 10 (see step (e) of FIG. 1).

  The method of FIG. 4 is the same as the method of FIG. 2 except that a bag-like multilayer film is also disposed on the lower base 21.

  When the two bag-like multilayer sheets 10 are attached to the lower base 21 and the upper base 22 as shown in FIG. 4, they are attached so that their MDs coincide with each other. For this reason, the package after heat-sealing the two bag-shaped multilayer sheets 10 (one in which the two bag-shaped multilayer sheets 10 are integrated) has the same MD, so that it is in one direction (MD) side. It is easy to tear.

  In particular, since the tear strength in the machine direction (MD) of the bag-shaped multilayer sheet 10 is 100 N / mm or less, it can be easily opened by the operator pulling the seal portions of the two bag-shaped multilayer sheets 10 by hand.

  Hereinafter, although an Example and a comparative example demonstrate in more detail, this invention does not receive a restriction | limiting at all.

  In addition, the various measured values and evaluation about the film displayed in this specification were performed as follows.

(1) Film-forming stability When the sheet was formed by the inflation molding method, the stability of the parison (preliminary molding) and the sticking to the pinch roll were observed and evaluated according to the following criteria.

◎: Extremely stable ○: Stable △: Slightly unstable (2) Elmendorf tear strength Tested according to the method of JIS K7128-2, and the resistance force when tearing one multilayer sheet is MD, Measurement was performed in two directions of TD. Usually, in order for an operator to tear the joint by hand, the tear strength of the sheet needs to be 100 N / mm or less.

(3) Gelboflex The test was conducted according to the method of ASTM F392, and it was represented by the number of pinholes in a multilayer sheet having a size of 200 × 300 mm ² .

(4) Sealing and holding As shown in FIG. 2, a bag-like multilayer sheet is attached to the upper base of the packing device, and a plate-like multilayer sheet is attached to the lower base. After covering, the four sides of the multilayer sheets were welded and sealed with a heat sealer, and it was visually evaluated whether they were kept sealed after one week.

○: The seal is maintained ×: The seal is broken (5) Transport failure The 600 kg sealed filter tow veil obtained in the above “(4) Seal retention test” After transporting with a clamp fork, the multilayer sheet was visually inspected for damage.

○: No damage to the multilayer sheet ×: Damage to the multilayer sheet (6) Unpacking workability 600 kg sealed filter toe veil bag-like multilayer sheet and multilayer obtained in the above “(4) Seal retention test” It was evaluated according to the following criteria whether the operator could easily open the heat seal part of the sheet by hand.

○: A level that can be easily opened along the heat-sealed part by one worker's hand. △: Can be opened by one operator's hand. Level ×: Level at which the heat seal part is not peeled off by the hand of one worker. Example The metallocene catalyst is used at the ratio shown in Tables 1 to 4 for forming the base layer (A) and the seal layer (C). MLLDPE (density 0.913 g / cm ³ , manufactured by Ube Maruzen Polyethylene Co., Ltd., “Umerit 1520F”) and LDPE (density 0.92 g / cm ³ , manufactured by Ube Maruzen Polyethylene Co., Ltd., “R300” )) Was used.

For the formation of the intermediate layer (B), mLLDPE (density 0.904 g / cm ³ , manufactured by Ube Maruzen Polyethylene Co., Ltd., “Umerit” in the ratio shown in Table 1 to Table 4 at a ratio shown in Table 1 to Table 4. 0520F ”) and 50% by mass of LDPE (density 0.92 g / cm ³ , manufactured by Ube Maruzen Polyethylene Co., Ltd.,“ R300 ”).

  Each mixture was coextruded to form a three-layer structure, and then a multilayer sheet having a thickness of 50 μm and a total thickness of 150 μm was obtained using an inflation molding machine.

Comparative Example Using each component shown in Tables 1 to 4, a multilayer sheet was obtained in the same manner as in the example.

Claims (2)

It is a bag-like multilayer sheet for packing filter tow bales,
The bag-like multi-layer sheet, which was cut multiple layer sheet into a square or rectangular, is folded into two in the horizontal direction at the time of sheet forming (TD), both ends of the longitudinal direction at the time of sheet forming (MD) are joined Is,
The multilayer sheet has a base material layer (A), an intermediate layer (B) and a seal layer (C),
The density range of 20 to 80% by mass of linear low density polyethylene (mLLDPE) having a density of 0.91 to 0.93, in which the base layer (A) and the seal layer (C) are polymerized using a metallocene catalyst. Of low density polyethylene (LDPE) of 80-20% by mass,
The intermediate layer (B) is composed of 20 to 80% by mass of mLLDPE having a density of 0.90 to 0.92 and 80 to 20% by mass of LDPE.
The density of mLLDPE forming the base layer (A) and the sealing layer (C) is higher than the density of mLLDPE forming the intermediate layer (B),
A bag-shaped multilayer sheet for packing a filter tow veil , having an overall thickness of 90 to 300 μm . A step of cutting the multilayer sheet into a square or a rectangle,
The multilayer sheet has a base material layer (A), an intermediate layer (B) and a seal layer (C),
The density range of 20 to 80% by mass of linear low density polyethylene (mLLDPE) having a density of 0.91 to 0.93, in which the base layer (A) and the seal layer (C) are polymerized using a metallocene catalyst. Of low density polyethylene (LDPE) of 80-20% by mass,
The intermediate layer (B) is composed of 20 to 80% by mass of mLLDPE having a density of 0.90 to 0.92 and 80 to 20% by mass of LDPE.
The density of mLLDPE forming the base layer (A) and the sealing layer (C) is higher than the density of mLLDPE forming the intermediate layer (B),
The total thickness is 90-300 μm,
The step of obtaining a bag-shaped multilayer sheet by joining the multilayer sheet cut into the square or rectangular shape in two in the transverse direction (TD) during sheet molding, and then joining both ends in the longitudinal direction (MD) during sheet molding;
The step of covering from one side of the filter tow veil with the bag-shaped multilayer sheet serving as the upper sheet,
The step of covering from the other side with the bag-shaped multilayer sheet or the multilayer sheet according to claim 1, which becomes a lower sheet,
Heat-sealing in a state where the upper sheet and the lower sheet are joined together,
A method for packing a filter tow veil having

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