JPS5941229A - Method for forming electroconductive two-tone tubular film - Google Patents

Abstract

PURPOSE:To form readily an electroconductive tubular film having transparent part, by selecting the viscosities of two raw resins, making the resin passages of an extruder appropriate, and using an air-cooling ring capable of adjusting partial cooling. CONSTITUTION:A thermoplastic resin (e.g. vinyl chloride resins) containing 30wt% or more carbon and a transparent thermoplastic resin free of carbon are selected such that the viscosity ratio of the former to the latter is 30:1 or less, and the thus selected resins are fed into an extruder. The cross-sectional areas of the passages of the extruder for said resins are constructed such that said area for the carbon-containing resin with a higher viscosity is large and said area for the transparent resin with a lower viscosity is small. The air-cooling ring can adjust partial cooling, and when an adjusting bolt 10 is fastened to lower a screening plate 9, the air amount of the side of the carbon-containing resin where the cooling rate is higher can be lowered to weaken the cooling, so that the intended electroconductive two-tone tubular film stock for producing an electroconductive bag can be readily produced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for forming an original conductive bag, ie, a tubular film, which is conductive and has a portion corresponding to a transparent window through which the contents can be confirmed.

Conventional two-color extruders or their systems are limited to forming substantially the same raw material and coloring only one side, or forming separate colored tubular films using the same raw material.

The present invention has a viscosity such as that of a resin containing 30% (weight) or more of carbon and a resin that does not contain carbon or a resin of the same type.
This is 1T extrusion molding, which allows two materials with large differences in thermal properties and strength to be made at the same time to approximately the same thickness, and the widths of both materials can be freely changed to the desired width. As mentioned above, if more than 30% (by weight) of carbon is added to impart conductivity, various properties will change from those of a resin that does not contain carbon, but it is desirable that the viscosity properties be as similar as possible. , whose viscosity ratio is (carbon-containing resin): (
It is necessary to select a resin that does not contain carbon, that is, a transparent resin with a limit of 30: 1 or less (carbon-free resin).

Next, with conventional molds for two-color extruders, molding is possible when the cross-sectional area of the resin flow path in the mold is equal and the viscosity is about the same, but when there is a difference in viscosity, the desired thickness and It is difficult to freely change or control the width of the conductive part and the transparent part.

Therefore, the mandrel shape (1) of the mold in Figure 1 is different from the conventional shape as shown in Figure 2, where the resin enters from (4) and (5).
In the present invention, as shown in Fig. 3, the partition wall plate (7) with the resin entering from the die body (7) is distributed from the center, but the position is shifted from the center to make the distribution uneven, as shown in Fig. 1. 3), the gap between them and the cross-sectional area of the flow path is made uneven, and the side with the larger cross-sectional area (4) is a flow path for carbon-containing resin with a higher viscosity, and the side with the narrower cross-sectional area (5) is the flow path of the carbon-containing resin. The channel is made of a transparent resin that does not contain carbon and has a low viscosity. The ratio is preferably 1.5:1 (3:2). The carbon-free resin flowing from the narrow side of the flow path is placed on the partition plate (
After passing through 7), it becomes one with the carbon-containing resin, and because of its low viscosity, it spreads widely and is discharged wider than the position partitioned by the partition plate (7). With conventional mandrels, the conductive part of the tubular film discharged is narrower and the transparent part is wider due to the difference in viscosity. Therefore, I was able to solve the problem by using the method described above.

Even if it is possible to change and control the thickness and width of the carbon-containing resin and the carbon-free resin until it comes out of the mold, the tubular film that comes out cannot be removed unless it is cooled, so a cooling device is required. However, in conventional air cooling rings, uniform air cooling acts on the tubular film.

However, when molding a conductive two-color tubular film, the conductive resin part containing carbon has different thermal characteristics from the resin part not containing carbon, and the conductive part cools extremely quickly, so Due to the pressure of the injected gas, the resin side that cools slowly and does not contain carbon, which is easy to stretch, expands more, resulting in one side of the bubble becoming bulged.

This difference in thermal properties between the two materials, as well as the difference in the property that the carbon content makes them more difficult to stretch than those without carbon, can be explained by comparing the degree of cooling of a portion of the tubular film as shown in Figures 4 and 5. By using an adjustable air cooling ring, stable molding with uniform bubbles that do not bulge is possible.

The shielding plate (9) shown in FIG. 5 is divided into 8 to 12 parts that can be moved up and down while sliding in front of the nozzle of the air cooling ring, and can be adjusted up and down individually using adjustment bolts α0). For example, in a resin part containing carbon, cooling can be weakened by tightening the adjustment port (QO) and lowering the shield plate to reduce the air volume. Since the present invention is a method for manufacturing a two-color tubular film original fabric for a conductive bag, the degree of conductivity required for the conductive bag varies depending on its contents. For example, in the case of a bag for semiconductor and electronic components, a two-color tubular film must be formed with a wide conductive part and a narrow transparent part. When molded using only a conventional two-color extrusion molding machine, the carbon-containing resin, ie, the conductive portion, is inevitably ejected in an extremely narrow width, so that it cannot be used as the raw material for the bag that serves the purpose. After taking measures such as optimizing the resin selection criteria, optimizing the resin flow path in the mold, and installing an air cooling ring that can adjust partial cooling, the conductive portion can be adjusted depending on the molding conditions of the extruder (scree rotation, temperature). It is possible to produce a two-color tubular film material having a wider width than the transparent part. The feature is that the width of the conductive portion and the transparent portion can be arbitrarily changed depending on the molding conditions.

There are various types of conductive bags, such as opaque bags that contain carbon, transparent bags that are usually vacuum-deposited with metal foil on thermoplastic resin, or multilayer film bags that are coated with metal. The cost and transparency that allows the contents to be confirmed are not satisfactory, so in the present invention, we use a two-color extruder that is excellent in mass production, and use a resin that has a high concentration of carbon added with excellent conductivity and a transparent resin that allows the contents to be confirmed. This method is characterized by the fact that a two-color tubular film is produced, and by using it as a raw material, conductive bags can be easily produced according to the purpose of use.

Examples of the present invention will be described below.

Example 1 From the annular mold (die) at the tip of a 50φ two-color twin-barrel extruder, one extruder was made of soft polyvinyl chloride (plasticizer Dop 40 pHR) containing 150% case, and the other extruder was made of transparent soft polyvinyl chloride containing no carbon. Polyvinyl chloride (plasticizer Dop)
29pHR) was simultaneously formed into a two-color tubular film. Carbon-containing polyvinyl chloride side molding conditions C3~C3165~
185℃, motor rotation 1800rpm, load current 11A
1 Transparent vinyl chloride side molding conditions 01~03160℃~18
0°C, motor rotation 1500 rpm, load current 12 A1 conductive part dl 175 ms, transparent part 16FIIIJ surface resistance transparent side 1~2 X i 011Ω, conductive side 6~
5. Xl (16Ω Example 2 50φ two-color twin-barrel type extruder, one side of the annular mold (die) at the tip of polyethylene MI-0,01 containing 50% carbon
The other extruder simultaneously molded a carbon-free transparent polyethylene copolymer M I = l: 1.5 into two tube-shaped foams, and the carbon-containing polyethylene side molded under conditions C, ~C3165~175°C motor. rotation 1000
pm, load current 14A1 transparent side polyethylene copolymer molding conditions 01~C3160~170℃, motor rotation 1
1000rp, load current 12A1 conductive part width 1007
1111. 90mJ in transparent part Surface resistance transparent side 8X1
09Ω5, conductive side s x i o6Ω

[Brief explanation of the drawing]

FIG. 1 shows an annular mold according to an embodiment of the present invention. FIG. 2 shows a conventional mandrel shape in the annular mold. FIG. 3 shows a new mandrel shape implemented in the present invention. FIG. 4 shows an example of an embodiment of the present invention. A plan view of the air cooling ring that is 4-L! + Procedural amendment 1, Indication of the case 1982 Patent Application No. 153065 2, Name of the invention Method for forming conductive two-color tubular film & Person making the amendment Relationship with the case Patent applicant

Claims (1)

[Scope of Claims] (a) A thermoplastic resin such as vinyl chloride resin or polyethylene containing high concentration carbon of 30% (weight) or more and a thermoplastic resin of the same or similar type that does not contain carbon in a two-color tubular shape. For extrusion molding into a film, the viscosity of both materials should be limited to within 1:60, preferably approximately the same viscosity. If the viscosity of both materials is 1:30 or more, or if the molding conditions do not allow the materials to be discharged at the desired ratio, adjust the cross-sectional area of each material in the mold to a ratio within 1:1 to 3=2. to be. - To cool the bubbles that expand with the pressure of the gas injected into the two-color tubular film that is discharged from the mold, the air volume is reduced to weaken the cooling for carbon-containing resins, and the cooling is increased by increasing the air volume for resins that do not contain carbon. An air cooling ring characterized by being able to increase the airflow, that is, by adjusting the air volume depending on the part of the air cooling ring. (2) By satisfying each of the above claims, by making a difference in the extrusion conditions of the corresponding post-material (for example, IJ, one rotation, temperature conditions, etc.), the conductive portion, that is, carbon, in the tubular film can be contained.゛The proportion of the resin part can be freely varied.