JP2014088181A - Packaging bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging bag which is used for hydrostatic pressure molding a laminated ceramic block, made of inexpensive materials without using a special device nor requiring so many days for performing processing, with improved productivity.SOLUTION: The packaging bag which is used for hydrostatic pressure molding a laminated ceramic block, formed by laminating a biaxial orientation polypropylene film which serves as a base material layer and a linear low-density polyethylene film which serves as a sealant layer via a polyethylene resin of a sandwich lamination process.

Description

  The present invention relates to a packaging bag.

  For the production of a multilayer ceramic capacitor, a piezoelectric speaker for a piezoelectric speaker, etc., a multilayer ceramic block formed into a block shape by stacking and crimping ceramic raw sheets is used.

  Conventionally, as a method of forming a multilayer ceramic block in which ceramic raw sheets are stacked and pressure-bonded and formed into a block shape, the stacked ceramic raw sheets are put in a packaging bag and vacuum packed, and this vacuum packed ceramic A molding method has been developed in which a stack of raw sheets is pressed from all directions by an isostatic press.

  In addition, after storing the stacked ceramic raw sheets in the receiving recess formed in the mold, the whole is put in a packaging bag and vacuum packed, and the stacked ceramic raw sheets packed in vacuum and the mold A method for forming a multilayer ceramic block has been devised, in which a pressure is applied in all directions by hydrostatic pressure pressing (Patent Document 1).

  As a packaging material such as a packaging bag used in the method of forming a multilayer ceramic block by this hydrostatic pressure press, it becomes a sealant on a nylon layer or a base material layer laminated by combining an ethylene / vinyl alcohol copolymer layer with a nylon layer. A multilayer film in which a polyolefin layer is laminated is sometimes used (Patent Documents 2, 3, and 4).

  These multilayer films have a problem in cost and the like as a packaging bag used between processes in the manufacturing process of the multilayer ceramic block. That is, since nylon or ethylene / vinyl alcohol copolymer is used, the material cost becomes high, and when the base material layer is made into a multilayer, a special multilayer extrusion processing apparatus is necessary for performing multilayer extrusion, However, there are problems that the number of processes is increased and the processing days are required to perform by bonding.

JP-A-1-208103 JP 2003-71999 A JP 2003-237794 A JP 2003-340994 A

  The present invention has been made in view of the above-described circumstances, and is a packaging bag used for an isostatic press for forming a multilayer ceramic block, which is low in material cost, without using a special device, and without taking a processing day. An object is to provide an inexpensive packaging bag with improved productivity.

The invention according to claim 1 of the present invention is a packaging bag used in an isostatic press for forming a multilayer ceramic block,
A packaging bag using a packaging material in which a biaxially stretched polypropylene film as a base material layer and a linear low density polyethylene film as a sealant layer are laminated via a polyethylene resin of a sandwich lamination method .

  The invention according to claim 2 of the present invention is the packaging bag according to claim 1, wherein the biaxially stretched polypropylene film has a thickness of 50 μm.

  The invention according to claim 3 of the present invention is the packaging bag according to claim 1 or 2, wherein the thickness of the linear low-density polyethylene film is 30 μm.

  The packaging bag of the present invention is a packaging bag used for the hydrostatic press for forming a multilayer ceramic block, the material cost is low, no special equipment is used, productivity is improved without taking processing days, It is also inexpensive.

It is explanatory drawing which showed the packaging material used for an example of the packaging bag of this invention typically by the cross section. It is explanatory drawing which showed typically an example of the packaging bag of this invention with the plane. (A), (B), (C) It is explanatory drawing which showed the state which prepares the ceramic raw sheet packaged in an example of the packaging bag of this invention by the perspective view. It is explanatory drawing which showed typically the state which packaged the ceramic raw sheet in an example of the packaging bag of this invention. It is explanatory drawing which showed typically the state which shape | molds a multilayer ceramic block in a cross section using an example of the packaging bag of this invention.

Hereinafter, embodiments for carrying out the present invention will be described.
FIG. 1 is an explanatory view schematically showing a packaging material used in an example of the packaging bag of the present invention in cross section, and FIG. 2 is an explanatory view schematically showing an example of the packaging bag of the present invention in plan view.

  The packaging material 100 used for an example of the packaging bag 200 of this example includes a biaxially stretched polypropylene film that becomes the base material layer 1 and a linear low-density polyethylene film that becomes the sealant layer 2 as shown in the cross-sectional view of FIG. A packaging material laminated through a polyethylene resin layer 3 of a sandwich lamination method.

  The biaxially stretched polypropylene film used as the base material layer 1 is commercially available for packaging applications. A biaxially stretched polypropylene film is preferable because it is transparent and the state of what is stored when it is made into a packaging bag can be confirmed.

  In addition, it is resistant to friction and piercing and has pinhole resistance. Therefore, as a packaging bag used for the hydrostatic pressure press for forming the multilayer ceramic block of this application, it is suitable for an application of vacuum packaging and pressing in hot water. The thickness is preferably 30 to 60 μm. In particular, a 50 μm biaxially stretched polypropylene film is preferred.

  The linear low-density polyethylene film used as the sealant layer 2 is synthesized using a single-site catalyst such as a metallocene catalyst because it has a narrow molecular weight distribution, low temperature heat sealability, and no low molecular weight components. The boil suitability is preferable.

  Moreover, since it has favorable transparency, since the state etc. of what was accommodated when it was set as the packaging bag can be confirmed, it is used preferably. As the thickness, since it is used for vacuum packaging in particular and does not require a strong sealing strength, a thickness of 25 μm to 50 μm is preferably used. Particularly preferred is 30 μm.

  For the polyethylene resin layer 3 of the sandwich lamination method, a low density polyethylene resin synthesized by a high pressure method can be preferably used. The melted low density polyethylene resin was extruded on the surface of the biaxially stretched polypropylene film to be the base material layer 1 by the sandwich lamination method, and at the same time, the linear low density polyethylene film to be the sealant layer 2 was extruded. It is laminated on the surface of the low density polyethylene resin by pressing.

At this time, it is preferable to apply an anchor coating agent to the laminate surface of the biaxially stretched polypropylene film to be the base material layer 1 (not shown in the figure). The anchor coating agent used is preferably a two-component curable urethane anchor coating agent. In this case, aging is necessary, but the application amount of the anchor coat liquid is about 1 g / m ² , so the aging days may be one day.

  Thereby, the packaging material 100 used for an example of the packaging bag 200 of this example is made. The packaging material 100 is laminated with the surfaces of the sealant layer 2 facing each other, and a sealing bag 4 is provided by sealing three sides, and a packaging bag 200 having an opening 5 at one end as shown in FIG. Made in a bag.

  Next, a method for forming a multilayer ceramic block will be described using the packaging bag 200 of this example.

  3 (A), (B), and (C) are perspective views illustrating a state of preparing a ceramic raw sheet to be packaged in an example of the packaging bag of the present invention, and FIG. 4 is an illustration of the packaging bag of the present invention. FIG. 5 is an explanatory view schematically showing a state in which a ceramic raw sheet is packaged as an example, and FIG. 5 is an explanatory view schematically showing a state in which a multilayer ceramic block is formed in a cross section using an example of the packaging bag of the present invention. It is.

  First, the laminated body 6 of the ceramic raw sheets on which the ceramic raw sheets of FIG. 3 (A) are stacked is housed in the recess of the mold 7 of FIG. 3 (B). Thus, the metal mold | die 7 which accommodated the laminated body 6 of the ceramic raw sheet | seat of FIG.3 (C) is prepared.

  Next, as shown in FIG. 4, the metal mold 7 containing the ceramic raw sheet laminate 6 is put in a packaging bag 200 and vacuum packed using a vacuum packaging machine. That is, the inside of the packaging bag 200 is evacuated, the opening 5 is sealed with an impulse seal, and the sealing seal portion 8 is provided and sealed. Thereby, the package 300 is created.

  As shown in FIG. 5, the package 300 is placed in a hydrostatic press 400, the hydrostatic press 400 is sealed, the inside of the hydrostatic press 400 is pressurized, and the package 300 is added from all directions. Press. Thereby, a laminated ceramic block is formed.

  The method of pressurizing the inside of the hydrostatic press 400 is not particularly limited, but the lid 9 of the hydrostatic press 400 is pressed inward by using a hydraulic pump, or the hydrostatic press 400 is inserted into the hydrostatic press 400. Pressure can be applied by feeding a liquid or the like. The liquid in the hydrostatic press 400 is temperature-controlled, and the temperature is preferably 70 ° C to 80 ° C.

  Specific examples of the present invention will be described below.

<Example 1>
The biaxially stretched polypropylene film (thickness 50 μm) of the base material layer 1 is set in an extrusion laminator, and a two-component curable urethane anchor coating agent is applied to the bonding surface and dried. Then, a low-density polyethylene resin having a polyethylene resin layer 3 melted is extruded from a T-type die of an extrusion laminator, and a polyethylene resin layer 3 having a thickness of 15 μm is provided. The sealant unwound from the sand shaft on the surface of the polyethylene resin layer 3 A linear low-density polyethylene film (thickness 30 μm) to be layer 2 was laminated and pressed by a nip roll to be laminated.

  This laminated body is aged in an aging room at 40 ° C. for 1 day, slit for bag making, and bag making is carried out with a bag making machine to produce a packaging bag of Example 1 with a three-side seal as shown in FIG. did.

  Below, the comparative example of this invention is demonstrated.

<Comparative Example 1>
Using a dry laminator, apply a two-component curable urethane adhesive to the surface of the biaxially stretched nylon film (thickness 15 μm) that will be the base material layer, dry it, and then apply the sealant layer to the adhesive application surface. A linear low-density polyethylene film (thickness: 60 μm) to be 2 was superposed, pressed with a nip roll, and laminated.

  This laminated body is aged for 3 days in an aging room at 40 ° C., slit for bag making, and bag making by a bag making machine to produce a packaging bag of Comparative Example 1 with a three-side seal as shown in FIG. did.

<Comparative example 2>
In the same manner as in Comparative Example 1, except that a biaxially stretched polypropylene film (thickness 50 μm) was used as the base material layer, and a linear low-density polyethylene film (thickness 80 μm) was used as the sealant layer 2. The packaging bag of Example 2 was made.

<Comparative Example 3>
A biaxially stretched polypropylene film (thickness 20 μm) and a biaxially stretched polypropylene film (thickness 20 μm) are bonded together using a two-component curable urethane adhesive in a dry laminator to form a two-layer base material layer. The two-layered base material paste was aged in an aging room at 40 ° C. for 3 days.

  This pasted book is used as a base material layer of two layers, a linear low density polyethylene film (thickness 25 μm) is used as a sealant layer, and an extruded laminator is used to extrude a melted low density polyethylene resin to obtain a low density of 15 μm in thickness. A packaging bag of Comparative Example 3 was prepared in the same manner as in Example 1 except that the two base material layers and the sealant layer were bonded together via the polyethylene resin layer.

<Comparative Example 4>
As a two-layer base material layer, a biaxially stretched polypropylene film (thickness 20 μm) and a biaxially stretched nylon film (thickness 15 μm) are bonded with a dry laminator using a two-component curable urethane adhesive. A packaging bag of Comparative Example 4 was prepared in the same manner as Comparative Example 3 except that the surface of the biaxially stretched nylon film was changed to a surface to be bonded to the low density polyethylene resin layer.

<Comparative Example 5>
A packaging bag of Comparative Example 5 was prepared in the same manner as Comparative Example 4 except that a biaxially stretched nylon film having a thickness of 25 μm was used instead of the biaxially stretched nylon film (thickness 15 μm).

<Comparison study>
About the following item, the packaging bag of the Example and the comparative example was compared and examined.

<Hot water aptitude>
The resistance to hot water at 80 ° C. was compared. The results are summarized in Table 1.

<Vacuum pack suitability>
The suitability when vacuum packed was comparatively evaluated. The results are summarized in Table 1.

<Friction resistance>
The resistance when the outer surfaces of the laminated bodies were rubbed against each other was compared. The results are summarized in Table 1.

<Puncture resistance>
The puncture resistance from the outer surface of the laminate was compared. The results are summarized in Table 1.

<Number of days to paste>
The number of days from the pasting to the end of aging was compared in creating the laminate. The aging days were estimated as 1 day for sandwich lamination and 3 days for dry lamination. The results are summarized in Table 1.

<Cost comparison>
We compared and compared material costs and processing costs. The results are summarized in Table 1.

以下に、実施例と比較例との比較結果について説明する。

Below, the comparison result of an Example and a comparative example is demonstrated.

<Comparison result>
Regarding hot water suitability, vacuum suitability, friction resistance, and puncture resistance, Comparative Example 2 is slightly inferior in puncture resistance, but the others are all good, and the packaging bags used for the method of forming a multilayer ceramic block by hydrostatic press As for, except for Comparative Example 2, there is no problem in use.

  In the production of the laminated body, the number of days for bonding is 2 days in Example 1 and Comparative Examples 1 and 2, and the number of processing days does not take and productivity is good. Moreover, in the cost comparison, Example 1 has the lowest cost and is inexpensive.

  Therefore, the packaging bag of Example 1 is good as a packaging bag used for the hydrostatic pressure press which shape | molds a multilayer ceramic block, and the number of manufacturing days is short, productivity is good, and it is cheap.

DESCRIPTION OF SYMBOLS 100 ... Packaging material 200 ... Packaging bag 300 ... Packaging 400 ... Hydrostatic press 1 ... Base material layer 2 ... Sealant layer 3 ... Polyethylene resin layer 4 ... Seal part 5 ... Opening part 6 ... Laminated body 7 of ceramic raw sheet ... Die 8 ... Sealing seal part 9 ... Lid

Claims (3)

A packaging bag used in an isostatic press for forming a multilayer ceramic block,
A packaging bag comprising a packaging material in which a biaxially stretched polypropylene film as a base material layer and a linear low density polyethylene film as a sealant layer are laminated via a polyethylene resin of a sandwich lamination method.   The packaging bag according to claim 1, wherein the biaxially stretched polypropylene film has a thickness of 50 μm. The packaging bag according to claim 1 or 2, wherein the linear low-density polyethylene film has a thickness of 30 µm.

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