JP2006220232A - Antistatic tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antistatic tube hard to charge, less in the amount of outgas, and good in joint connectability. <P>SOLUTION: At least the inner peripheral face is formed of a polyester elastomer composition which contains a polymeric antistatic agent as a polyolefine/polyether copolymer. The weight ratio of the polyester elastomer to the polymeric antistatic agent is 80:20 to 95:5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tube having an antistatic function (referred to as an antistatic tube in this specification).

  In recent years, piping has been used in various fields, but resin tubes have been adopted in consideration of weight reduction and piping workability.

  However, in a piping system with a large flow rate, the resin tube is charged by friction with the fluid, and a spark may be generated depending on the situation, so that a worst situation may occur in which a hole is formed in the resin tube.

  As one means for solving the above problem, for example, an antistatic resin tube connection structure as shown below has been developed.

  This antistatic resin tube connection structure has a structure in which a nipple made of a conductive metal and a resin tube mixed with a conductive material are connected by a connector made of a nonconductive resin, and one end of the nipple is a nipple. In the inside of the conductive material, the other end is provided on the inner surface of the tube so as to be grounded in contact with the electrically connected state (for example, Patent Document 1). According to this hypothetical antistatic resin tube connection structure, since the charge is hardly accumulated in the resin tube, the above-mentioned worst situation does not occur.

  However, when this connection structure is used, there is a trouble that a ground must be attached, and there is a problem that a spark occurs if the use of the ground is forgotten.

Therefore, in order to develop a tube that is hard to be charged even if it is made of resin, we focused on molding the resin tube with a resin to which a polymeric antistatic agent was added, and on that basis, good joint connectivity At the same time, we started developing a resin tube with a small amount of outgas that can be used in a so-called clean room.
JP 2001-141170 A

  Therefore, an object of the present invention is to provide an antistatic tube that is hardly charged, has a small outgas amount, and has good joint connectivity.

(Invention of Claim 1)
In the antistatic tube of the present invention, at least the inner peripheral surface is formed from a polyester elastomer composition containing a polymer type antistatic agent which is a polyolefin / polyether copolymer. The ratio of-): (polymer type antistatic agent) is 80:20 to 95: 5 by weight.

(Invention of Claim 2)
In the antistatic tube of the present invention, at least the inner peripheral surface is formed from a polyester-based elastomer composition containing a polymer-type antistatic agent that is a copolymer of polyethylene oxide and amide. The ratio of the system elastomer): (polymer type antistatic agent) is 80:10 to 95: 2.5 by weight.

(Invention of Claim 3)
The antistatic tube of the present invention is formed of a polyethylene resin composition containing at least an inner peripheral surface of a polymer type antistatic agent which is a polyolefin / polyether copolymer. ): (Polymeric antistatic agent) is 90:10 to 93: 7 in weight ratio.

(Invention of Claim 4)
The antistatic tube according to the present invention relates to the invention according to any one of claims 1 to 3, wherein the surface resistivity of the inner peripheral surface of the tube is 1.0E + 11Ω or less and the amount of outgas per hour. Is 550 μg / m ² or less.

  According to the antistatic tube of the present invention, it is difficult to be charged, the amount of outgas is small, and the joint connectivity is good.

  Embodiments as the best mode for carrying out the antistatic tube of the present invention will be described in detail below.

(About the antistatic tube of this embodiment 1)
In this antistatic tube, at least the innermost layer is formed from a polyester-based elastomer composition containing a polymer-type antistatic agent which is a polyolefin / polyether copolymer, and the above (polyester elastomer): The ratio of (polymer type antistatic agent) is set to X: Y by weight ratio. Note that three types of samples of X: Y = 95: 5 (sample 1) / 90: 10 (sample 2) / 80: 20 (sample 3) are prepared.

  Here, the polyester elastomer used as the tube base material is a thermoplastic polyether ester elastomer, and the polyolefin / polyether copolymer includes polyethylene / polyether, polypropylene / polyether, and the like.

  In Example 1, specifically, Toray DuPont Co., Ltd. “Hytrel 5077 (registered trademark, the same shall apply hereinafter)” is used as the polyester-based elastomer, which is a polyolefin / polyether copolymer. As a molecular type antistatic agent, Sanyo Chemical Industries, Ltd. “Pelestat 300 (registered trademark, the same applies hereinafter)” is used. The polymer type antistatic agent that is a polyolefin / polyether copolymer includes a random copolymer, a block copolymer, and a graft copolymer, and a block copolymer is particularly preferable. The same applies to the third embodiment. In the antistatic tube, “Hytrel 5077” and “Pelestat 300” are mixed by a mixer for about 30 minutes and then discharged from a nozzle through a die while being kneaded by a screw type extruder. To manufacture. At this time, the temperature near the inlet of the extruder is about 215 ° C. The temperature from the middle to the outlet is about 225 to 230 ° C. The temperature near the inlet of the die is 235 ° C. The temperature near the outlet of the die is about 230 ° C. It is set.

(About the performance test of the antistatic tube of this embodiment 1)
Using three types of antistatic tubes with an outer diameter of 8 mm and an inner diameter of 6 mm manufactured by the above method, (1) Chargeability test (measurement of surface resistivity in the tube), (2) Clean performance test (outgas (3) Joint jointability (test to see cracks when connected to joints) was performed.

"Test method"
(1) Chargeability test As shown in FIG. 4, a cylindrical brass electrode is inserted from both ends of the tube by a depth of 10 mm so as to be in close contact with the inner surface of the tube. The measured value at this time is converted into the surface resistivity by the following formula.

Surface resistivity (Ω) = measured resistance (Ω) x (tube inner diameter x 3.14) / (tube sample length-electrode insertion depth)
The measuring instrument is Advantest Corporation “Digital Super Resistance Meter R8340”, which has an applied voltage of 500 V and an applied time of 1 minute.

  In this test, if the surface resistivity is 1.0E + 11Ω or higher, the test cannot be used (x), and if it is lower, the test can be used (◯).

(2) Clean performance test a. Caps made of SUS316 washed so that the outgas generation amount is 1 ng or less are attached to both ends of the cut sample tube, and samples 1, 2, and 3 are formed so that the exposed portion of the tube is 100 mm.
b. The sample 1 is accommodated in a sufficiently washed cylindrical SUS container having a diameter of 175 mm and a depth of 50 mm.
c. As shown in FIG. 5, high-purity nitrogen gas (99.9995%) from a nitrogen gas cylinder is flow meter → activated carbon filter → cylindrical SUS container (with sample 1 inside) → collection tube (adsorbent-filled glass tube) ) Route the pipe to flow in an airtight state in the route of). Then, the volatile components generated from the sample 1 are purged with the high-purity nitrogen gas and collected by an adsorbent (Akzo RESEARCH LABORATORY, TenaxGR) filled in the collection tube.
d. The collected components were qualitatively quantified by a gas chromatograph mass spectrometer thermal desorption method. In quantification, the peak area was determined as a toluene equivalent value.

These tests are also performed on samples 2 and 3. The gas collection conditions are a temperature of 25 ° C. and a nitrogen gas purge amount of 300 ml / min for 1 hour.
In addition, this test is judged when the amount of outgas collected by the adsorbent exceeds 550 μg / m ² (the amount of outgas collected by the adsorbent when no antistatic agent is added to the polyolefin resin). Cannot be used (×). The same applies to Examples 2 and 3.

(3) Joint jointability After repeating the cooling cycle of -50 ° C to 80 ° C five times for samples 1, 2, and 3, a joint with a diameter of 5.9 mm at the insertion end and a maximum diameter of 6.8 mm was sampled. Inserted into 1, 2 and 3, and when a crack occurs, it is unusable (X), and when it does not occur, it is usable (O).

  This antistatic tube is formed from a polyester-based elastomer composition containing a polypropylene-based resin and a polymer-type antistatic agent which is a copolymer of polyethylene oxide and amide, and the above-mentioned (polyester-based elastomer). ) :( Polymer type antistatic agent) :( Polypropylene resin) is set at a weight ratio of X1: Y1: Y2. Note that three samples of X1: Y1: Y2 = 95: 2.5: 2.5 (sample 4) / 90: 5: 5 (sample 5) / 80: 10: 10 (sample 6) were prepared. ing.

  Here, the polyester elastomer used as a tube base material is the same as that of Example 1.

  Examples of the polymer antistatic agent that is a copolymer of polyethylene oxide and amide include polyether ester amide and polyether amide imide.

  In Example 2, specifically, Toray DuPont Co., Ltd. “Hytrel 5077” is used as the polyester elastomer (polypropylene resin and polyethylene oxide / amide copolymer). As a polymer type antistatic agent, Maruhishi Oil Chemical Co., Ltd. “Denon MB50P (registered trademark, the same applies hereinafter)” is used.

  The production method of the antistatic tube and the performance test of the antistatic tube are the same as in Example 1.

  In Example 2, the antistatic tube is formed including the polypropylene resin. However, since the polypropylene resin serves only as a binder, the same effect can be obtained without including the polypropylene resin. It is thought to play a function. That is, the ratio of (polyester elastomer) :( polymer type antistatic agent) may basically be X1: Y1 = 95: 2.5 / 90: 5/80: 10.

  The polypropylene resin contains about 20% of low molecular weight material, but when the low molecular weight material was removed, the elution was very small, and it was confirmed that the outgas performance was greatly improved. .

  This antistatic tube is formed from a polyethylene resin composition containing a polymer antistatic agent which is a polyolefin / polyether copolymer, and the above (polyethylene resin): (polymer antistatic) The ratio of the agent is set to X2: Y3 by weight. Three types of samples, X2: Y3 = 95: 5 (sample 7) / 90: 10 (sample 8) / 80: 20 (sample 9), are prepared.

  Here, examples of the polyethylene resin used as the tube base material include low density polyethylene, ultra-low density polyethylene, and linear low density polyethylene. The polyolefin / polyether copolymer is the same as in Example 1. is there.

  In Example 3, specifically, Nippon Unicar Co., Ltd. “GS650” is used as the polyolefin resin, and Sanyo is used as a polymer type antistatic agent which is a polyolefin / polyether copolymer. Kasei Kogyo Co., Ltd. “Pelestat 300” is used.

  The antistatic tube is manufactured by mixing “GS650” and “Pelestat 300” with a mixer for about 30 minutes and then discharging from a nozzle through a die while kneading with a screw type extruder. To do. The temperature near the inlet of the extruder at this time is about 185 ° C. The temperature near the middle to the outlet is about 195 to 200 ° C. The temperature near the inlet of the die is 200 ° C. The temperature near the outlet of the die is about 200 ° C. It is set. The production method of the antistatic tube and the performance test of the antistatic tube are the same as in Example 1.

[About the test results of Sample 1 to Sample 9]
(1) Chargeability test When the surface resistivity of Samples 1 to 3 in Example 1 was observed, the surface resistivity of each sample was 1.0E + 11Ω or less, and Samples 1 to 3 were determined to be (◯) (see FIG. 1). ).
From the surface resistivity of Samples 4 to 6 in Example 2, Samples 4 to 6 were determined to be (◯) (see FIG. 2).
From the surface resistivity of Samples 7 to 9 of Example 3, Sample 7 was judged as (x), and Samples 8 and 9 were judged as (O) (see FIG. 3).

(2) Clean performance test Since the amount of outgas collected by the adsorbent in all of Samples 1 to 9 is 550 μg / m ² or less, all of Samples 1 to 9 were judged to be (◯) for the clean performance test. .

(3) Joint bondability Since cracks occurred in only sample 9 among samples 1-9, other samples 1-8 were judged as (◯).

(4) Comprehensive judgment From the above (1) to (3), Samples 7 and 9 were judged as (x), and Samples 1, 2, 3, 4, 5, 6 and Sample 8 were judged as (◯). This is shown in FIG.

  As is clear from the graph of FIG. 3 showing the results of the chargeability test in Example 3, the ratio of (polyethylene resin) :( polymer type antistatic agent) is 90:10 to 93 in weight ratio. : 7 indicates that the determination is (◯).

  Further, in Example 1, the ratio of (polyethylene resin) :( polymer type antistatic agent) is set to 80:20 to 95: 5 in weight ratio so that the above effect can be sufficiently exhibited. From the graph, it can be predicted that the determination will be (◯) even if it is about 80:20 to 96: 4.

  Furthermore, in Example 2, the ratio of (polyester elastomer) :( polymer type antistatic agent) is set to 80:10 to 95: 2.5 in weight ratio so that the above effect can be sufficiently exhibited. From the graph of FIG. 2, even if it is about 80:10 to 96: 2, the determination can be expected to be (◯).

(About other forms)
In Example 1 described above, a polyester-based elastomer is used as the tube base material. However, even when this is replaced with a polyurethane-based elastomer or a polyamide-based elastomer, an equivalent function is exhibited.

  That is, the structure of the antistatic tube is described as follows: “At least the inner peripheral surface is formed of a polyurethane-based elastomer composition containing a polymer-type antistatic agent that is a polyolefin / polyether copolymer, ): (Polymer type antistatic agent) may be 80:20 to 95: 5 by weight.

  Further, the antistatic tube has the following structure: “At least the inner peripheral surface is formed of a polyamide-based elastomer composition containing a polymer-type antistatic agent that is a polyolefin / polyether copolymer, ): (Polymer type antistatic agent) may be 80:20 to 95: 5 by weight.

3 is a graph showing the results of a chargeability test on Samples 1 to 3 in Example 1. 6 is a graph showing the results of a chargeability test on Samples 4 to 6 in Example 1. The graph which shows the result of the electrification test of the samples 7-9 of Example 1. FIG. Explanatory drawing of the apparatus used for the charging test. Flow chart used for clean performance test. The table | surface which shows the comprehensive determination of the samples 1-9 of Examples 1-3.

Claims (4)

At least the inner peripheral surface is formed of a polyester elastomer composition containing a polymer antistatic agent which is a polyolefin / polyether copolymer, and the above (polyester elastomer): (polymer antistatic agent) ) In a weight ratio of 80:20 to 95: 5. At least the inner peripheral surface is formed from a polyester elastomer composition containing a polymer antistatic agent which is a copolymer of polyethylene oxide and amide, and the above (polyester elastomer): (polymer charging) An antistatic tube characterized in that the ratio of (inhibitor) is 80:10 to 95: 2.5 by weight. At least the inner peripheral surface is formed from a polyethylene resin composition containing a polymer antistatic agent which is a polyolefin / polyether copolymer, and the above (polyethylene resin): (polymer antistatic agent) Is an antistatic tube characterized in that the weight ratio is 90:10 to 93: 7 by weight. 4. The charging according to claim 1, wherein the tube has a surface resistivity of 1.0E + 11Ω or less and an outgas amount per hour of 550 μg / m ² or less. Prevention tube.

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