JP2022034862A - Resin pipe for electric fusion and manufacturing method thereof - Google Patents

Abstract

To provide a resin pipe for electric fusion capable of detecting connection failure resulting from forgetting to scrape work.SOLUTION: A resin pipe 1 for electric fusion has a resin pipe body 10, and a poorly fused layer 11 existing on the outer surface of the resin pipe body 10. A part of the outer surface of the resin pipe body 10 in a pipe axial direction is a planned fusion region 12 used for fusion with the inner surface of an electric fusion joint. The poorly fused layer 11 is composed of a resin composition having an MFR of less than 2.3 g/10 minutes, has a thickness of 550 μm or less, and is continuously present in at least the planned fusion region 12 in the pipe axial direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electrofusion resin tube and a method for manufacturing the same.

The electric fusion joint used for connecting the resin pipes is made of thermoplastic resin and has receiving ports at both ends. A heating element is embedded in the inner circumference of each receiving port, and when the heating element is energized with the end of the resin tube inserted in the receiving port, the inner peripheral surface of the receiving port and the outer periphery of the end of the resin tube are energized. The surface is melted and both sides are fused, so that the electric fusion joint and the resin pipe are joined.

A skin layer containing impurities, oxidative deterioration substances, bleed-out of additives, etc. may be attached to the outer surface of the resin tube. The skin layer is not removed by cleaning with acetone, which hinders good fusion. Therefore, it is necessary to scrape the outer surface of the end of the resin tube before electric fusion.

As a method of preventing forgetting to perform the scraping work, a method of preliminarily marking the outer surface of the end portion of the resin tube and a method of laminating an identification layer having a color different from that of the resin tube are known (for example, Patent Document 1). ). When the outer surface is scraped, the marking and identification layer are removed, so it is possible to visually confirm that the scraping work is completed.
However, the only visual method is the possibility of forgetting the scraping work and neglecting to confirm the completion of the scraping, resulting in the electric fusion of the resin pipe with the skin layer and the electric fusion joint. A little remains.

Normally, after the electric fusion is completed, water pressure is applied to the water passage space of the resin pipe and the electric fusion joint, and the presence or absence of leakage at the joint between the two is inspected (hydraulic inspection). If the end of the resin tube is not scraped, a defective joint can be found due to water leakage during the water pressure inspection. However, depending on the outer surface condition of the resin pipe, the bonding defect may become fine, and there is a possibility that the water leakage cannot be detected at the time of the water pressure inspection and the judgment of acceptance is received. In this case, water leakage from the joint portion starts after the start of service, and the water leakage condition may worsen with the passage of time.

Therefore, Patent Document 2 proposes a method of adhering a fusion-inhibiting layer made of a material that does not fuse with an electric fusion joint at the time of electric fusion to the outer surface of the end portion of the resin tube.
In this method, the resin pipe and the electric fusion joint can be electrically fused by scraping to remove the fusion-inhibiting layer. However, if the scraping work is forgotten and electrical fusion is performed, the resin pipe and the electrical fusion joint will not be fused in the region where the fusion inhibition layer exists, so water leakage will always occur during the hydraulic pressure inspection and a bonding failure will be detected. be able to.

Japanese Unexamined Patent Publication No. 6-2794 Japanese Unexamined Patent Publication No. 2019-158147

However, in the method described in Patent Document 2, in order to attach the fusion-inhibiting layer to the outer surface of the resin tube, it is necessary to provide an adhesive layer between them, so that the thickness of the layer to be removed by scraping becomes large. There is an inconvenience.
The present invention provides a novel electrofused resin tube capable of detecting a joining defect caused by forgetting to scrape work, and a method for manufacturing the same.

The present invention has the following aspects.
[1] It has a resin pipe main body and a poorly fused layer existing on the outer surface of the resin pipe main body, and a part of the outer surface of the resin pipe main body in the pipe axial direction is the inner surface of the electric fusion joint. It is a planned fusion region used for fusion, and the poorly fused layer is made of a resin composition having an MFR of less than 2.3 g / 10 minutes, has a thickness of 550 μm or less, and is at least scheduled to be fused. An electrofusion resin tube that is continuously present in the region in the direction of the tube axis.
[2] The electrically fused resin tube according to [1], wherein the solubility parameter of the resin contained in the poorly fused layer is 15.3 (J / cm ³ ) ^1/2 or more.
[3] The electrically fused resin tube according to [1] or [2], wherein the resin contained in the poorly fused layer is polypropylene.
[4] The electrically fused resin tube according to any one of [1] to [3], wherein the resin contained in the resin composition constituting the outer surface of the resin tube main body is polyethylene.
[5] The electrically fused resin tube according to any one of [1] to [4], wherein the resin tube main body and the poorly fused layer are molded by a coextrusion method.
[6] A method for manufacturing an electrically fused resin tube according to any one of the above [1] to [4], wherein the resin tube main body and the poorly fused layer are molded by a coextrusion method. How to manufacture a resin tube.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an electrically fused resin tube capable of detecting a joining defect caused by forgetting to scrape work, and a method for manufacturing the same.

It is a top view which shows one Embodiment of the electric fusion resin tube which concerns on this invention. It is an enlarged cross-sectional view of a main part along the line AA of FIG.

The MFR (melt mass flow rate) of a thermoplastic resin is a value indicating the fluidity of the resin in a molten state, and the test method is specified in JIS and ISO.
For example, the MFR of polyethylene is specified in JIS K 6922-1: 2018, and is measured under the conditions of a temperature of 190 ° C. and a load of 5.0 kg. Further, the MFR of polypropylene is specified in JIS K 6921-2 (ISO 19069-2: 2016), and is measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kg.

<Resin tube worn by electric fusion>
FIG. 1 is a plan view of the electrically fused resin tube of the present embodiment, and FIG. 2 is an enlarged cross-sectional view of a main part along the line AA of FIG.
The electrically fused resin tube 1 (hereinafter, also simply referred to as a resin tube) of the present embodiment has a resin tube main body 10 and a poorly fused layer 11 existing on the outer surface of the resin tube main body 10. The resin tube main body 10 is cylindrical and has openings 10a and 10b at both ends.

In the electric fusion between the electric fusion-wearing resin pipe 1 and the electric fusion joint (hereinafter, also simply referred to as a joint), as will be described later, a part of the outer peripheral surface (heating region 10c) of the resin pipe main body 10 and the inside of the joint. The peripheral surface is fused.
In the pipe axis direction of the resin pipe main body 10, the region from the opening 10a of the resin pipe main body 10 to the end 10e of the heating region 10c in the vicinity thereof is the planned fusion region 12 used for fusion with the inner surface of the joint. The distance from the opening 10a of the resin tube main body 10 to the start end 10d of the heating region 10c and the distance from the start end 10d to the end 10e of the heating region 10c in the pipe axis direction are determined by the structure of the joint used for electric fusion.

The resin tube main body 10 is made of, for example, a resin composition containing polyolefin as a main component. As used herein, the term "resin composition containing polyolefin as a main component" means a resin composition containing 50% by mass or more of polyolefin. Specifically, a resin composition composed of one or more kinds of polyolefins, or a resin composition containing one or more kinds of polyolefins and, if necessary, an additive can be exemplified. A resin composition containing fibers may be used.
As the polyolefin, polyethylene is preferable, and high-density polyethylene (HDPE) is more preferable.
In the present embodiment, the resin tube main body 10 is made of a uniform resin composition. It may have a structure in which two or more layers having different compositions are laminated in the radial direction.
The radial size of the resin tube main body 10 is, for example, a nominal diameter of 20 to 300 (outer diameter 27 to 355 mm, thickness 3.4 to 32.2 mm).

Polyethylene is preferable as the resin contained in the resin composition (hereinafter, also referred to as "resin composition B") constituting the outer surface of the resin tube main body 10. The MFR of the resin composition B is preferably 0.1 to 2.3 g / 10 minutes, more preferably 0.2 to 2.0 g / 10 minutes. When the MFR of the resin composition B is at least the lower limit of the above range, the moldability is excellent, and when it is at least the upper limit, it is difficult to fuse with the poorly fused layer.
In the present specification, the MFR of the resin composition B containing polyethylene is a value measured under the conditions of a temperature of 190 ° C. and a load of 5.0 kg in accordance with JIS K 6922-1: 2018.

In the present embodiment, the poorly fused layer 11 has a band shape continuous in the tube axial direction of the resin tube main body 10, and exists over the entire length of the resin tube main body 10.
The poorly fused layer 11 is a layer made of a resin composition having an MFR of less than 2.3 g / 10 minutes (hereinafter, also referred to as “resin composition A”). If the MFR is less than 2.3 g / 10 minutes, the poorly fused layer 11 and the inner peripheral surface of the joint are difficult to fuse, and water leakage is likely to occur during a water pressure inspection. The MFR is preferably 2.0 g / 10 minutes or less.

The resin composition A is, for example, a resin composition containing one or more kinds of resins and, if necessary, additives. A coloring component such as a pigment may be contained as an additive.
The solubility parameter of the resin contained in the resin composition A is preferably 15.3 (J / cm ³ ) ^1/2 or more, more preferably 17.0 (J / cm ³ ) ^1/2 or more, and 19.0 (19.0). J / cm ³ ) ^1/2 or more is more preferable. When the solubility parameter is at least the above lower limit value, the adhesive force between the poorly fused layer 11 and the resin tube main body 10 tends to be weakened, and peeling tends to occur at the interface between the two.
It is preferable that the resin contained in the resin composition A is different from the resin contained in the resin composition B constituting the outer surface of the resin tube main body 10. The absolute value of the difference between the two dissolution parameters is preferably 1.0 (J / cm ³ ) ^1/2 or more, more preferably 1.5 (J / cm ³ ) ^1/2 or more, and 2.0 (J / cm 3) or more. cm ³ ) ^1/2 or more is more preferable, 3.0 (J / cm ³ ) ^1/2 or more is particularly preferable, and 4.0 (J / cm ³ ) ^1/2 or more is most preferable. When the absolute value of the difference between the dissolution parameters is not more than the above lower limit value, the adhesive force between the poorly fused layer 11 and the resin tube main body 10 tends to be weakened, and peeling tends to occur at the interface between the two.
For example, the solubility parameter of HDPE used for manufacturing the resin tube main body 10 is 14.8 to 18.1 (J / cm ³ ) ^1/2 from the polymer database.

The resin contained in the resin composition A is preferably polypropylene. The polypropylene may be a homopolymer (homopolypropylene) or a copolymer (random polypropylene, block polypropylene). One type of polypropylene may be used, or two or more types of polypropylene may be used in combination. It is more preferable that the resin composition A contains homopolypropylene.
The solubility parameter of homopolypropylene is 15.3 to 19.0 (J / cm ³ ) ^1/2 (literature value, polymer database).

The MFR of the resin composition A containing polypropylene is preferably 0.3 g / 10 minutes or more, preferably less than 2.3 g / 10 minutes, and more preferably 0.45 to 2.0 g / 10 minutes. If the MFR is at least the lower limit of the above range, the moldability is excellent, and if it is at least the upper limit, water leakage is likely to occur during the water pressure inspection.
In the present specification, the MFR of the resin composition A containing polypropylene is a value measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kg in accordance with JIS K 6921-2 (ISO 19069-2: 2016).

The thickness of the poorly fused layer 11 is 550 μm or less, preferably 300 μm or less. If the thickness of the poorly fused layer 11 is not more than the above upper limit value, water leakage is likely to occur during the water pressure inspection. It can also be easily removed by scraping.
The lower limit of the thickness of the poorly fused layer 11 is not particularly limited and is more than zero. From the viewpoint of ease of molding, 5 μm or more is preferable, and 10 μm or more is more preferable.
The thickness of the poorly fused layer 11 is obtained by measuring the thickness of the poorly fused layer 11 in the radial direction of the resin tube 1 in a cross section perpendicular to the tube axis direction of the resin tube 1. If the thickness of the poorly fused layer 11 is not uniform in the circumferential direction of the resin tube 1, the maximum value is set to the thickness of the poorly fused layer 11.

<Manufacturing method>
The resin tube 1 of the present embodiment can be manufactured by molding the resin tube main body 10 and the poorly fused layer 11 by a coextrusion method.
In the coextrusion method, the resin composition constituting the resin tube main body 10 and the resin composition A constituting the poorly fused layer 11 are simultaneously extruded using two extruders and laminated by passing through one die. At the same time, it is molded into a desired shape.
If the molding is performed by the coextrusion method, it is not necessary to provide an adhesive layer between the resin tube main body 10 and the poorly fused layer 11, so that the thickness of the layer to be removed by scraping can be reduced. This makes the scraping work more stable and easier.
Further, if molding is performed by the coextrusion method, it is easy to reduce the cost of equipment and raw materials at the time of molding. Further, since the molding temperature is not high as compared with the method described in Patent Document 2, stable production is easy.

<How to use>
The resin pipe 1 can be connected to each other or to another resin pipe via an electric fusion splicer. The shape of the joint is not limited. For example, a joint having a tubular shape, having receiving ports at both ends, and having an inner diameter of the receiving port corresponding to the outer diameter of the resin tube main body 10 can be used.

The joint is made of, for example, a resin composition containing polyolefin as a main component. Specifically, a resin composition composed of one or more kinds of polyolefins, or a resin composition containing one or more kinds of polyolefins and, if necessary, an additive can be exemplified.
As the polyolefin, polyethylene is preferable, and high-density polyethylene (HDPE) is more preferable.

Polyethylene is preferable as the resin contained in the resin composition (hereinafter, also referred to as "resin composition C") constituting the inner surface of the joint. The MFR of the resin composition C is preferably 0.2 g / 10 minutes or more, and more preferably 0.4 g / 10 minutes or more in that a good fused state can be easily obtained. The upper limit is preferably 1.5 g / 10 minutes or less, more preferably 2.0 g / 10 minutes or less in terms of fusion performance.
In the present specification, the MFR of the resin composition C containing polyethylene is a value measured under the conditions of a temperature of 190 ° C. and a load of 5.0 kg in accordance with JIS K 6922-1: 2018.

It is preferable that the resin contained in the resin composition A constituting the poorly fused layer 11 is different from the resin contained in the resin composition C constituting the inner peripheral surface of the joint. The absolute value of the difference between the two dissolution parameters is preferably 1.0 (J / cm ³ ) ^1/2 or more, more preferably 1.5 (J / cm ³ ) ^1/2 or more, and 2.0 (J). / Cm ³ ) ^1/2 or more is more preferable, 3.0 (J / cm ³ ) ^1/2 or more is particularly preferable, and 4.0 (J / cm ³ ) ^1/2 or more is most preferable. When the absolute value of the difference between the dissolution parameters is not more than the above lower limit value, the bonding force between the poorly fused layer 11 after electric fusion and the inner peripheral surface of the joint is likely to be weakened, and peeling is likely to occur at the interface between the two. ..
For example, the solubility parameter of HDPE used for manufacturing an electrically fused joint is 14.8 to 18.1 (J / cm ³ ) ^1/2 (literature value, polymer database).

The electric fusion step can be performed by the following procedure.
In advance, the end portion of the resin tube main body 10 including the planned fusion region 12 is scraped to scrape off the poorly fused layer 11 and the skin layer (layer containing impurities, oxidation-degrading substances, bleed-out of additives, etc.). The scraping operation can be performed using, for example, a cutting tool such as a pan or a polishing tool such as a sander. After scraping, the end of the resin tube main body 10 is cleaned with acetone to remove shavings and the like adhering to the resin tube body 10 so as to be in a state suitable for electric fusion.

The end portion of the resin tube main body 10 that has been scraped is inserted into the receiving port of the joint to a predetermined position. For example, the end portion of the resin tube main body 10 is inserted until it abuts on the positioning protrusion protruding from the inner peripheral surface of the receiving port.
Next, the heating element embedded in the inner peripheral surface of the receiving port is energized. When energized, the heating element generates heat, and the resin composition in the vicinity of the heating element is heated and melted. That is, a part of the inner peripheral surface of the receiving port and a part of the outer peripheral surface of the resin tube main body 10 in the vicinity thereof (heating region 10c) are melted. Since these melts expand thermally, they are pressurized in the socket. When the melt is solidified by cooling after being energized for a predetermined time, the inner peripheral surface of the joint and the outer peripheral surface of the resin pipe main body 10 are integrally joined. In this way, the electric fusion between the joint and the resin pipe 1 is completed.
After the electrical fusion is completed, a water pressure test is performed. The water pressure test is preferably performed under the conditions of a test water pressure of 1.75 MPa and a holding time of 1 minute.

In the resin tube 1 of the present embodiment, if the scraping operation is forgotten and the scraping completion is neglected and the electric fusion is performed (that is, the poorly fused layer 11 is present on the outer surface of the planned fusion region 12). When electrical fusion is performed), as shown in Examples described later, water leakage occurs during the water pressure inspection, and bonding defects can be detected.
The reason is considered as follows. Since the resin composition A constituting the poorly fused layer 11 has a low MFR, it is difficult to flow during electric fusion, and the fused state tends to be weak. When the MFR of the resin composition A is less than 2.3 g / 10 minutes, it is difficult for the melt of the poorly fused layer 11 to mix with the melt of the inner peripheral surface of the joint and the outer peripheral surface of the resin pipe body 10. It is considered that the joint strength after these are cooled and solidified becomes very weak. Further, when the thickness of the poorly fused layer 11 is 550 μm or less, it is considered that stress concentration is likely to occur on the poorly fused layer 11 at the time of water pressure inspection. As a result, if the water pressure test is performed in a state where the resin pipe 1 and the joint are electrically fused without scraping, the water pressure easily causes peeling of the fusion interface or destruction of the poorly fused layer 11. It is believed that water leakage will definitely occur.

Further, when the solubility parameter of the resin constituting the poorly fused layer 11 is 15.3 (J / cm ³ ) ^1/2 or more, the difference from the solubility parameter of the resin constituting the resin tube main body 10 tends to be large. .. As a result, at the time of electric fusion, the melt of the poorly fused layer 11 hardly mixes with the melt on the outer peripheral surface of the resin tube main body 10, and peeling easily occurs at these interfaces after cooling and solidification.
Further, when the solubility parameter of the resin constituting the poorly fused layer 11 is 15.3 (J / cm ³ ) ^1/2 or more, the difference from the solubility parameter of the resin constituting the joint tends to be large. As a result, at the time of electric fusion, the melt of the poorly fused layer 11 hardly mixes with the melt of the inner peripheral surface of the joint, and peeling easily occurs at these interfaces after cooling and solidification.

Further, if the color of the poorly fused layer 11 and the color of the outer surface of the resin tube main body 10 are different, it can be visually confirmed that the poorly fused layer 11 has been removed, so that the completion of the scraping work can be easily confirmed. It is preferable in that.

The resin pipe 1 of the present embodiment can also be used for connection by a mechanical joint (packing water stoppage, cap nut tightening, etc.) without removing the poorly fused layer 11. Since the poorly fused layer is thin, the water blocking function by packing etc. is not impaired.

In the present embodiment, the poorly fused layer 11 is provided over the entire length of the resin tube main body 10, but the poorly fused layer 11 may be continuously present in the tube axial direction at least in the planned fusion zone 12.
For example, when the resin pipe 1 is cut to an arbitrary length and used, since an arbitrary position of the resin pipe main body 10 can be the planned fusion region 12, the poorly fused layer 11 is formed over the entire length of the resin pipe main body 10. It is preferable that they exist continuously. On the other hand, when the resin tube 1 is used without being cut, the poorly fused layer 11 may be provided only at the end including the planned fusion zone 12.
It is preferable that the poorly fused layer 11 is continuously present over the entire length of the resin tube main body 10 in that the resin tube main body 10 and the poorly fused layer 11 can be easily molded at the same time by a coextrusion method.

Further, in the present embodiment, the band-shaped refractory layer 11 is present in a part of the resin tube main body 10 in the circumferential direction, but the refractory layer may be present in the entire circumferential direction.
For example, the entire outer surface of the resin tube main body 10 may be covered with the poorly fused layer 11. Alternatively, when the poorly fused layer is provided only at the end of the resin tube main body 10, the poorly fused layer may be present over the entire circumference of the end.
When the poorly fused layer 11 has a band shape, the width of the poorly fused layer 11 in the circumferential direction is preferably, for example, 5 mm or more, and more preferably 10 mm to 170 mm.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
(Examples 1 to 10)
Examples 1 to 6 are Examples, and Examples 7 to 10 are Comparative Examples.

A resin composition A constituting the poorly fused layer 11 and a resin composition B (MFR: 0.4 g / 10 minutes) constituting the resin tube main body 10 were prepared.
The resin contained in the resin composition A is homopolypropylene (solubility parameter: 17.0 (J / cm ³ ) ^1/2 ), and the resin contained in the resin composition B is HDPE (solubility parameter: 16.4 (dissolution parameter: 16.4). J / cm ³ ) ^1/2 ). The resin composition A was colored black, and the resin composition B was colored blue.
As the resin composition A, three types having different MFRs (the following resin compositions A1 to A3) were prepared.
Resin composition A1: MFR is 0.45 g / 10 minutes.
Resin composition A2: MFR is 2.0 g / 10 minutes.
Resin composition A3: MFR is 2.3 g / 10 minutes.

The resin composition A and the resin composition B were molded by a coextrusion method to produce a resin tube 1 having the structure shown in FIGS. 1 and 2.
The resin tube main body 10 made of the resin composition B has a nominal diameter of 50, an outer diameter of 60 mm, a thickness of 5.5 mm, and a length of 5 m.
The poorly fused layer 11 made of the resin composition A is continuously provided over the entire length of the resin tube main body 10 so as to cover the entire outer surface of the resin tube main body 10.
The types of the resin composition A and the thickness of the poorly fused layer 11 were changed as shown in Table 1 to produce 10 types of resin tubes 1 (Examples 1 to 10).

In each example, two of the obtained resin pipes (5 m) were joined via an electric fusion splicer without scraping, and then a hydraulic pressure test was performed by the following method.
The resin contained in the resin composition C constituting the inner peripheral surface of the electric fusion joint is HDPE (solubility parameter: 16.4 (J / cm ³ ) ^1/2 ), and the MFR of the resin composition C is 0. It was .4 g / 10 minutes.
[Water pressure inspection]
A water pressure of 1.75 MPa was applied to the pipeline composed of the two resin pipes and the electric fusion joint to hold the pipe for 1 minute, and then the pressure was once reduced to 1.0 MPa. After 3 minutes had passed while maintaining this water pressure, the presence or absence of water leakage was visually confirmed.
Table 1 shows the results as ◯ when water leakage occurred and × when no water leakage occurred.

As shown in Table 1, Examples 1 to 6 in which the MFR of the resin composition A constituting the poorly fused layer is less than 2.3 g / 10 minutes and the thickness of the poorly fused layer is 550 μm or less are shown. A large amount of water leaked. Therefore, it was possible to detect a poor connection due to forgetting to scrape.
On the other hand, in Example 7 in which the MFR of the resin composition A was less than 2.3 g / 10 minutes but the thickness of the poorly fused layer was 700 μm, no water leakage could be confirmed.
Further, in Examples 8 to 10 in which the thickness of the poorly fused layer was 550 μm or less, but the MFR of the resin composition A was 2.3 g / 10 minutes, no water leakage could be confirmed.

1 Electric fusion-wearing resin tube 10 Resin tube body 11 Difficult-to-fuse layer 12 Planned fusion area

Claims (6)

It has a resin tube main body and a poorly fused layer existing on the outer surface of the resin tube main body.
A part of the outer surface of the resin pipe body in the pipe axial direction is a planned fusion region used for fusion with the inner surface of the electric fusion joint.
The poorly fused layer is made of a resin composition having an MFR of less than 2.3 g / 10 minutes, has a thickness of 550 μm or less, and is continuously present in at least the planned fusion region in the tube axial direction. , Electric fusion wearing resin tube. The electrically fused resin tube according to claim 1, wherein the solubility parameter of the resin contained in the poorly fused layer is 15.3 (J / cm ³ ) ^1/2 or more. The electrically fused resin tube according to claim 1 or 2, wherein the resin contained in the poorly fused layer is polypropylene. The electrofusion resin tube according to any one of claims 1 to 3, wherein the resin contained in the resin composition constituting the outer surface of the resin tube body is polyethylene. The electrically fused resin tube according to any one of claims 1 to 4, wherein the resin tube main body and the poorly fused layer are molded by a coextrusion method. The method for manufacturing an electrically fused resin tube according to any one of claims 1 to 4, wherein the resin tube main body and the poorly fused layer are molded by a coextrusion method. Manufacturing method.

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