JPH0132114B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Field of Application> The present invention relates to a method for manufacturing sterilizing packaging materials, and more particularly to a method for manufacturing sterilizing packaging materials that require both gas permeability and peelability, such as medical packaging materials. <Conventional technology> Traditionally, ethylene oxide gas (hereinafter referred to as EOG)
There is a known method of sterilizing medical instruments such as syringe needles in a packaged state using a gas such as As shown in the plan view in Figure 1 and the cross-sectional view in Figure 2, the packaging of objects to be sterilized, such as medical instruments, is made of gas-permeable materials such as paper (including mixed paper) and nonwoven fabric. 1, heat sealing resin composition 2
The object to be sterilized 3 is placed on it and covered with a gas-impermeable synthetic resin sheet 4 that has been molded in advance, and the peripheral edge 5 is integrated by heat sealing. It is common that the The sterilizing gas enters the inside of the material 1 having gas permeability through the non-heat-sealed portion as shown by the arrow in FIG. 2, and the object 3 to be sterilized is sterilized. When using the object 3 to be sterilized, the gas-impermeable synthetic resin sheet 4 is peeled off and the object 3 to be sterilized is taken out. As is clear from the above description, the packaging material for gas sterilization needs to have gas permeability and appropriate peelability. On the other hand, stable strength that does not easily peel off except during use is also required. By the way, in order to apply the heat-sealing resin composition 2 to the gas-permeable material 1, it is common to apply it all over the entire surface by printing means using a gravure printing plate. In this case, on the gravure printing plate,
A gravure white line screen is often used to form cells that hold the heat-sealing resin composition 2. Conventionally, such a white line screen for gravure has been used, for example, as shown in Fig. 3.
inch, the width of the transparent part a and the width of the opaque part b
The ratio (linear ratio) of 1:3 to 1:2 or 30
/inch with a linear ratio of about 1:3. By using this white line screen, stable heat sealing strength can be obtained. In addition, by using a gravure screen with a linear ratio of 1:2 to 2:3 at 10 to 20/inch, the width of the gravure printing plate is widened, thereby ensuring the required gas permeability. is also being carried out. <Problems to be Solved by the Invention> However, when a gravure plate is created using a white line screen as described above, the following problems have occurred. Generally, when a gravure plate is created using a white line screen for gravure whose transparent part has a width a of 250 μm or less, as shown in Fig. 5,
The heat-sealing resin composition 2 provided on the material 1 becomes continuous, and if it is 300 μm or more, it is no longer continuous, and if it is between 250 μm and 300 μm, it becomes continuous or discontinuous. It is said to be unstable. For example, when using a white line screen with a line ratio of 1:3 at 40/inch as described above, the width of the transparent part is approximately
The width is narrowed to 160 μm, and furthermore, due to side etching during corrosion, the dowel portion of the gravure printing plate becomes extremely narrow. FIG. 4 is an explanatory cross-sectional view of the gravure printing plate 6 when a normal screen such as the white line screen for gravure shown in FIG. 3 is used, and corresponds to the line AA of the screen shown in FIG. 3. When the cell portions 7 of such a gravure printing plate 6 are filled with a heat-sealing resin composition and applied on the gas-permeable material 1, the width of the groove 8 is very narrow. As shown in the figure, the heat-sealing resin composition 2 is applied in a continuous manner, and the actual applied area becomes 100%. Therefore, in this case, the heat sealing strength is strong, but on the other hand, since there is no uncoated part on the entire surface, the required gas permeability is insufficient, and it is not suitable as a packaging material for gas sterilization. On the other hand, when using a screen with a transparent part width of 300 μm or more, such as a screen with a linear ratio of 1:2 to 1:3 and a screen ratio of 10 to 20/inch, heat sealing resin composition 2 is Since it is coated in a shape and a non-coated portion is formed, gas permeability can be obtained. However, in this case, if the line ratio is 1:2, the proportion of the opaque area to the whole is about 44%, and if the line ratio is 1:3, the proportion of the opaque area is about 56%.
%, and both have the disadvantage that the heat-sealing strength becomes weaker because the coating area of the heat-sealing resin composition becomes smaller. The width of the transparent part of the gravure white line screen is between 250 μm and 250 μm.
When making a gravure plate using a 300μm material, the heat sealing resin composition 2 may vary depending on various factors such as the viscosity and temperature of the coating material, the pressure applied to the plate cylinder during printing, and the surface condition of the material 1. The state of the coating changes greatly, making stable production virtually impossible. Therefore, the present invention has developed a sterilization packaging material that can stably produce products that have a good balance of both properties required for sterilization packaging materials, such as sufficient gas permeability and sufficient heat sealing strength. The purpose is to provide a manufacturing method for. <Means for Solving the Problems> In other words, the present invention provides a method in which the width of the transparent portion is 250 μm.
Below is a gravure screen with a pattern in which a part of the opaque part of the gravure white line screen, in which the area of the opaque part occupies 44% or more of the whole, is converted into a transparent part under the conditions (a) to (d) below. A gravure plate is prepared by using the gravure plate, and the resin composition for heat sealing is applied to the entire surface of one side of the material having gas permeability, and a large number of independent minute non-coated parts are present, and one side of the coated area is coated with the resin composition for heat sealing. 65% of the area of
This is a method for producing a sterilization packaging material, characterized in that the coating material is applied in a range of ~85%. (b) The amount of conversion must be 10 to 32% of the entire opaque area. (b) The distance to at least one adjacent opaque portion is 300 to 500 μm. (c) There must be at least an unconverted opaque part among the opaque parts of all rows and columns. (d) The converted portion is uniformly distributed throughout. <Function> When a gravure plate for applying a heat-sealing resin composition is prepared using the white line screen having the above-described specific configuration, the gravure plate has a dot width.
A portion of 250 μm or less and a portion of 300 μm to 500 μm are formed in a mixed manner. When the heat-sealing resin composition is applied using this gravure plate, the heat-sealing resin composition is continuously applied to the portions where the dot width is 250 μm or less. Further, in the 300 μm to 500 μm portion, since the coating is applied in a dotted manner, a non-coated portion is formed. These continuous coating portions and dotted coating portions are formed to be almost uniformly dispersed when viewed from the whole, and their coating area is 65% to 85% of the whole. <Example> Next, the present invention will be described with reference to the drawings. The packaging material obtained by the present invention has a structure as shown in FIG. In the figure, 1 is a material having gas permeability, and 2 is a heat-sealing resin composition. The white line screen used in the present invention is based on a white line screen in which the width of the transparent part is 250 μm or less and the area of the opaque part is 44% or more of the total area, and this screen is converted under specific conditions. . FIG. 7 is a partially enlarged explanatory view of the gravure screen used to obtain the sterilization packaging material of the present invention, and shows a part of the opaque part F of the pattern of the gravure white line screen as shown in FIG. The converted pattern is shown in the transparent part. The part indicated by the dotted line in the figure is the conversion part H. The amount of cutting of the opaque portion is such that the distance between the opaque portion I adjacent to the cut conversion portion H and the remaining opaque portion J is 300 μm or more and 500 μm or less.
By setting it to 300 μm or more, the heat sealing resin composition is not continuous in this part,
Therefore, gas permeability can be ensured. Also
By setting the thickness to 500 μm or less, the remaining opaque portion J can ensure sufficient depth during corrosion. The width a of the transparent part in the part that is not converted is
The thickness is 250 μm or less, and therefore, when the heat-sealing resin composition is applied by printing, it is continuously applied to this area, so that it has sufficient heat-sealing strength. In this case, in order to satisfy both sufficient gas permeability and heat sealing strength, the amount of conversion of the opaque area to the transparent area should be 10% of the total opaque area.
~32%. If it is less than 10%, sufficient gas permeability cannot be ensured, and if it is more than 32%, the heat sealing strength will be insufficient. At this time, the area of the heat-sealing resin composition applied is 65% to 85%. FIG. 8 shows a gravure printing plate 9 obtained using a gravure screen having the pattern shown in FIG.
FIG. 7 is an explanatory cross-sectional view corresponding to the section taken along line B-B in FIG. 7. Dote 10 is a portion that has not undergone conversion and is therefore narrow, but dote 11 is wide to correspond to a portion that has undergone conversion. A material 1 having gas permeability is obtained by filling the cell portions 12 of such a gravure printing plate with a heat-sealing resin composition.
When printing is performed on the top, the heat-sealing resin composition 2 is in a continuous state in the narrow doves 10 and is not printed in the wide dots 11, as shown in FIG. Figure 10 is a collection of several patterns shown in Figure 7, but in order to use it as an actual gravure screen, the basic pattern shown in Figure 7 must be created and the example shown in Figure 10 made using a printing press. In this way, a large number of basic patterns are collected. As is clear from FIG. 10, there must be untransformed opaque parts in all rows and columns of the pattern. In the case of the row indicated by the arrow in FIG. 10, there is an untransformed opaque portion 13. The presence of such an unconverted opaque portion 13 can prevent the area of the converted portion 14 from becoming too large and weakening the intensity locally. Therefore, even if the width of the heat-sealed portion is narrow, sufficient strength can be ensured. In addition, when converting a part of an opaque area to a transparent area, it is necessary to prevent the conversion from being unevenly localized on a single gravure screen, and it is necessary to ensure that the conversion is uniform throughout. It is natural that there is such a difference due to the nature of the gravure screen. The gravure screen for obtaining the sterilization packaging material of the present invention may be a collection of basic patterns as shown in FIGS. 11, 12, and 13. Various other basic patterns are possible, such as those other than the 3x3 basic pattern, or cutting two adjacent opaque areas across the transparent area to reduce the width of the transparent area.
Various methods can be considered, such as a case where the thickness is 300 μm to 500 μm. Next, more specific examples of the present invention will be shown. The basic pattern of a gravure screen having the basic pattern shown in FIG. 3 with a line count of 40/inch and a line ratio of 1:3 was converted into a basic pattern as shown in FIG. In this case, the width c of the transparent part is
The width of transparent portion a was approximately 160 μm. A large number of these converted basic patterns were assembled using a printing press to create a gravure screen with a line count of 40/inch and a line ratio of 1:3. A gravure plate with a plate depth of 150 μm was created using this gravure screen, and a heat seal lacquer made of a mixture of ethylene-vinyl acetate copolymer and ester resin (total solid content 25%) was made using this gravure plate. Gas permeable material (S Veran (manufactured by Tokushu Paper Co., Ltd.))
It was applied on top using a gravure printing method. The packaging material thus obtained sufficiently fulfilled the necessary functions as a packaging material for gas sterilization in terms of heat sealing strength and gas permeability. The following table shows the functions of the packaging material obtained according to the present invention in comparison with the functions of the packaging material obtained in the same manner using other screens.

[Table] In the table, A is 40/inch, linear ratio 1:
B shows the packaging material obtained with the conventional screen of No. 3, B the screen of the invention, C the packaging material obtained with the conventional screen with a linear ratio of 15/inch of 1:2, and D the functionality required for the packaging material. <Effects of the Invention> As described above, according to the present invention, a gravure plate is created using a gravure screen with a specific configuration, and a heat-sealing resin composition is applied using the gravure plate. The sealing resin composition is formed in a uniform mixture of continuous application parts and dotted application parts, and the application area is
Since it is 65 to 85%, sufficient heat sealing strength can be obtained, preventing careless opening, and the heat sealing strength is such that paper peeling does not occur when opening the package. In addition, sufficient gas permeability is obtained, so a packaging material suitable for EOG sterilization etc. can be obtained. The width of the gravure plate is 250 μm or less or 300 μm to 500 μm, and the coating state of the heat sealing resin composition is not affected by slight changes in manufacturing conditions, so it is stable. Quality products can be manufactured easily. The sterilization packaging material of the present invention is particularly useful when both gas permeability and heat seal strength are required, such as packaging materials for medical devices that undergo EOG sterilization or autoclave sterilization, such as disposable injection needles and syringes. Shows excellent effects.

[Brief explanation of drawings]

1 and 2 are a plan view and a cross-sectional view showing the packaging state of the object to be sterilized, respectively, FIG. 3 is an explanatory view of a normal gravure screen, and FIGS. An explanatory diagram showing a gravure printing plate and the printing state by the printing plate when using the gravure screen shown in the figure, FIG. 6 is a cross-sectional explanatory diagram of the sterilization packaging material of the present invention, and FIG. 7 is a sterilization use of the present invention. An explanatory diagram of an example of a gravure screen for obtaining packaging materials, and FIGS. 8 and 9 are explanatory diagrams showing a gravure printing plate and the printing state by the printing plate when the gravure screen of FIG. 7 is used, respectively. , FIG. 10 is an explanatory diagram of the assembled state of the basic pattern of FIG. 7, and FIGS. 11 to 13 are explanatory diagrams of other examples of gravure screen patterns for obtaining the sterilization packaging material of the present invention. Each is shown below. 1... Material having gas permeability, 2... Resin composition for heat sealing, 3... Item to be sterilized, 4... Gas impermeable synthetic resin sheet, 5... Peripheral end, 6,
9... Gravure printing plate, 7, 12... Cell part,
8, 10, 11... Dote, 13... Unconverted opaque part, 14... Converted part, a... Width of transparent part, b... Width of opaque part, H... Converted part, I
... Adjacent opaque area, J... Remaining opaque area.

Claims (1)

[Scope of Claims] 1. A part of the opaque part of a gravure white paper screen in which the width of the transparent part is 250 μm or less and the area of the opaque part occupies 44% or more of the whole is subject to the following conditions (a) to (d). Create a gravure plate using a gravure screen with a pattern converted into a transparent part,
Using the above-mentioned gravure plate on the entire surface of one side of the gas-transparent material, the resin composition for heat sealing is applied so that many independent minute non-coated parts exist and the coated area is 65% to 85% of the area of one side. A method for producing a packaging material for sterilization, characterized in that the coating material is applied in a range of %. (b) The amount of conversion must be 10 to 32% of the entire opaque area. (b) The distance to at least one adjacent opaque portion is 300 to 500 μm. (c) There must be at least an unconverted opaque part among the opaque parts of all rows and columns. (d) The converted portion is uniformly distributed throughout.