JP3378777B2 - Engraving method of polyethylene bag - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for engraving a polyethylene bag by engraving a lower portion of a seal near the bottom of the bag. 2. Description of the Related Art Polyethylene bags made of LDPE, LLDPE, and HDPE, especially clean polyethylene bags manufactured in a clean room, are formed and bagged in an environment of a class of 1,000 to 100,000. With the goal of eliminating foreign matter such as kogation and dirt, all items are inspected visually and shipped. Such polyethylene bags are
It is used for packaging and coating of articles that require strict quality standards, such as bulk pharmaceuticals, tablets, polycrystalline silicon IC parts, and special resins. [0003] The above polyethylene bags are shipped without any mark, but when it is necessary to assign lot numbers to the bag products, a certain number of the bag products are packed together and labeled. Of course, the lot number is displayed on the label, but nothing is displayed on the bag-making product for each bag, and the lot cannot be tracked after the product is used. Recent Product Liability Act (P
L method), ISO9000, GMP method, etc., the management of products becomes strict, and display management is required for clean polyethylene bags for follow-up investigation when there is a problem. [0004] In general, as a display method of a PE bag, printing of flexo, gravure, etc., ink jet, transfer printing, sticker, etc. can be considered, but printing, printing, etc. on a clean LDPE bag are considered. Foreign matter may be attached to the film, and the product may be soiled due to processing errors or the like. Therefore, an object of the present invention is to provide an engraved polyethylene bag that is not based on printing, transfer, and the like, and also provides a method of engraving under a seal simultaneously with sealing by utilizing sealing heat at the time of bag making. The purpose is to do so. [0005] In order to achieve the above object, the present invention provides a polyethylene bag by engraving a seal lower portion of a bag with a heat seal bar. A silicone rubber coated sheet is interposed between the seal bar and the polyethylene bag as a heat-resistant sheet, and an opaque mark is formed under the seal by pressing the heat seal bar . A tube formed in a clean room is formed under a clean condition by heat sealing the bottom of the bag. At this time, printing is performed on the lower part of the seal at the same time as the sealing process by the heat seal bar with the engraving tool, and the engraving is performed. When an engraving tool having the same temperature as the seal bar is pressed through a heat-resistant sheet, opaque engraving can be performed under the bag seal by the whitening phenomenon of PE. FIG. 1 is a perspective view showing an example of the polyethylene bag of the present invention. A tube of LDPE (low density polyethylene) formed in a clean room is heat-sealed at the bottom of the bag under clean conditions to form a bag. The bottom of the bag 10 is formed by a heat seal 12
At the appropriate position under the seal 14 of the bag formed from to the cut end 13, characters and graphics are pressed by the heat stamping tool 28 (FIG. 3) attached to the heat seal bar 21 at the same time as the heat sealing of the bag bottom. , Symbols and the like are marked. Due to the above cutting in the bag making process, an opening 11
Is formed. The engraving process varies depending on the thickness of the LDPE bag, the processing speed, and the like.
This is achieved by pressing the stamp held at 80 ° C. for 0.2 to 3.0 seconds. FIG. 2 is a side view schematically showing an apparatus for performing a method of printing under the seal simultaneously with the heat sealing of the bottom of the bag. LDP in 100000 clean environment
The tube is extruded from the E resin with an inflation molding machine, folded at a folding diameter of 90 mm to 1300 mm, and wound up after an intermediate inspection. The wound tube 18 is pulled out from the unreel and is fed to the sealing device 20 at a constant speed in a flat state. Tube 1 passing over the upper surface of anvil 22
A heat-resistant sheet 23 made of a silicon rubber coating sheet is stacked on 8, and a hot plate 26 of a heat seal bar 21 is pressed to perform sealing. At the same time, an engraving portion 14 is formed under the seal 14 by pressing an engraving tool 28. The heat-resistant sheet 23 is for preventing polyethylene from being fused to the stamping tool to facilitate release, and for providing an opaque stamp on the lower seal 14. A portion of the engraved tube 18 away from the seal portion is cut by a cutter 24 to cut the PE bag 10 (FIG. 1).
After manufacturing a certain number of sheets, it is sent to the product inspection process. In the drawing, reference numeral 17 denotes a rubber belt conveyor, and 19 denotes a delivery roller. In the illustrated example, the LDPE tube formed by an inflation extruder is cooled, flattened and wound and drawn from a reel to form a bag and engraved. It is possible to process continuously from making to bag making and engraving. FIG. 3 is an enlarged sectional view of the sealing device 20. The mounting member 30 is fixed to the upper part of the anvil 22, and the T-slot 27 is provided on the side surface of the mounting member 30, and the seal bar 21 is mounted to be able to move up and down. A hot plate 26 extending in the width direction of the bag is arranged inside the seal bar 21, and a marking tool 28 is provided at a position away from the hot plate 26 by a predetermined distance. The hot plate 26 and the marking tool 28 are supported by a pressing means 29 so as to be able to move up and down. The heating plate and the means for heating the marking tool 28 are not shown. The engraving tool 28 may fix characters, figures, numbers, symbols, etc., but the engraving tool 28 may be provided with a numbering type engraving changing means 25 to have a structure in which characters, numbers, etc. can be exchanged. With a replaceable structure, the marking can be changed for each bag or for each lot. In the bag making process, the heat seal bar 21 is used.
If the temperature of the stamping tool 28 is substantially the same as that of the
Although the engraved portion 15 of FIG. 4 is also fused, the heat-resistant sheet 23 interposed between the tube 18 and the heat seal bar 21 and the engraving tool 28 may be a fluorine resin coated sheet or the like. By using this, an opaque mark can be formed under the bag seal by the whitening phenomenon of the PE film. No foreign matter or contamination is attached even by these engraving processes. Products can be identified by engraving for each bag or for each lot,
Follow-up of products can be secured. Example 1 An LDPE tube having a thickness of 0.2 mm and a folding width of 440 mm formed by an inflation extruder in a clean room of class 100,000 is flattened, and sealing is performed by a sealing device. Was. The heat-resistant sheet is a silicone rubber coated sheet (SG-S 0.1 manufactured by Arisawa Seisakusho)
When both the seal bar and the marking tool were subjected to pressure bag making at a temperature of 280 ° C. for 1.2 seconds, a clean polyethylene bag having an opaque stamp under the seal was completed. <Example 2> An LDPE tube having a thickness of 0.12 mm and a folding width of 850 mm was prepared using an inflation extruder as in Example 1, and a heat-resistant sheet was used at the time of sealing with a sealing device. When the stamping tool was subjected to pressure bag making at 220 ° C. for 0.7 seconds, a clean polyethylene bag having an opaque stamp under the seal was completed. <Embodiment 3> As in Embodiment 2, the thickness is set to 0.1 mm.
An HDPE tube with a width of 03 mm and a fold width of 200 mm was prepared. The same heat-resistant sheet was used during the sealing process, and both the seal bar and the stamping tool were subjected to pressure bag making at 260 ° C for 0.3 seconds. A clean polyethylene bag with an opaque stamp was completed. <Embodiment 4> A thickness of 0.1 as in Embodiment 1.
An LDPE tube having a length of 2 mm and a folding width of 850 mm was prepared, and a fluororesin-coated sheet (Chukko Kasei Kogyo FGF-500-3) was used during sealing with a sealing device.
When pressure bag making was performed for 2 seconds, a clean polyethylene bag with a transparent mark under the seal was completed. As described above, the polyethylene bag of the present invention is stamped under the seal of the bag at the same time as the heat sealing.
There is no risk of lowering the sealing strength. The engraving under the seal for each bag or for each lot makes it possible to identify the product, and it is possible to track the product. Further, in addition that have a advantage that not the cost for which can be imprinted in-line during the bag making polyethylene bags, PE by pressing through a heat resistant sheet at the time of sealing work
An opaque mark can be made under the bag seal by the whitening phenomenon of the stencil.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an example of the polyethylene bag of the present invention. FIG. 2 is a side view schematically showing an apparatus for performing a method of engraving under a bag seal simultaneously with heat sealing of a bottom of the bag. FIG. 3 is an enlarged sectional view of the sealing device. [Description of Signs] 10 Polyethylene bag 11 Opening 12 Sealing part 13 Cut end 14 Seal under bag 15 Marking part 17 Belt conveyor 18 Tube 19 Delivery roller 20 Sealing device 21 Seal bar 22 Anvil 23 Heat resistant sheet 24 Cutter 25 Marking change Means 26 Hot plate 27 Groove 28 Marking tool 29 Pressurizing means 30 Mounting member

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B65B 61/02 B65D 33/00

Claims (1)

(57) [Claims] [Claim 1] When a tube formed in a clean room is heat-sealed at the bottom of the bag under clean conditions to form the bag, the bottom of the bag is formed by a heat seal bar with an engraving tool. In the method of printing on the lower part of the bag seal simultaneously with the heat sealing process of
A method for engraving a polyethylene bag, wherein an opaque engraving is made under the seal by interposing a silicone rubber coated sheet as a heat-resistant sheet between the heat seal bar with the engraving tool and the polyethylene bag.