JPS5945872B2 - Fitting with packing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a joint with a packing, and more particularly to a novel pipe joint in which a threaded portion is coated in advance with a packing coating layer having lubricity and sealing properties.

During piping construction for the transfer of drinking water, industrial water, etc., white paint was applied to the threads of pipe fittings and steel pipes to prevent leakage of internal fluids. It is customary to apply or spread a tape made of green or unfired polytetrafluoroethylene (green tape).

However, since the liquid sealant is 30 to 40% solvent, there is an extremely high possibility of leakage or contamination of water depending on the conditions of use. That is, after the liquid sealant is applied to the threaded part, it is dried for 3 to 5 minutes to evaporate most of the solvent, and then the parts are fitted and tightened. After completing the piping, it is best to leave it for at least 24 hours to dry completely before water is passed through. In practice, a larger amount than necessary is often applied, and not only is it wasted, but the excess amount spills out and becomes a major cause of water pollution such as cloudiness, odor, and taste. Also, regarding the problem of drying, the fitting is often done at the same time as application, and as a result, the seal is sealed with a large amount of solvent in it, so the solvent evaporates over time, thinning the sealant and causing leaks. It is becoming. Furthermore, if water is passed immediately after such piping construction, the solvent may cause water pollution. On the other hand, raw tape does not require drying or curing time, has no effect on water pollution even if water is passed through it immediately after piping, and although there are concerns about its pressure resistance, it is not suitable for liquid sealants. In comparison, there are disadvantages such as poor construction workability, relatively high cost, difficulty in applying to large diameter pipes, and poor returnability for centering after piping is completed.

Furthermore, since zinc rust prevention is no longer possible for water supply system components, particularly joints, steel pipes, etc., they are now coated with plastic as an alternative for rust prevention. In particular, the deep threaded part of the joint (usually two threads) and the end face of the steel pipe must be treated to prevent rust during construction. Liquid sealants can also have rust prevention properties, and can be applied to prevent rust and seal at the same time, but in the case of raw tape, there is the inconvenience of having to prepare a separate rust preventive agent. . Furthermore, with conventional liquid sealants, after fitting and tightening,
Even after curing for about an hour, pressure resistance is poor and leakage is a problem.

In the case of raw tape, sufficient pressure resistance can be achieved by completely degreasing the joints and steel pipes, but incomplete degreasing, such as by simply wiping, slightly reduces the pressure resistance. and,
When the tape is rotated 90 degrees for centering after fitting and tightening, the pressure resistance of the liquid sealant is significantly impaired, and the pressure resistance of the raw tape is reduced to less than half. Moreover, in the case of liquid sealant, the fitting,
After a certain amount of time has elapsed after tightening, the return torque becomes extremely large, making disassembly and repair difficult. Based on the recognition of the above-mentioned problems, the present inventor has conducted various studies,
As a result of repeated studies, we found that all of the above-mentioned problems could be solved by forming a packing coating layer that has lubricating and sealing properties on the threaded portion of the pipe joint in advance and is made of a mixture of a binder with rubber-like elasticity and a solid lubricant. I found out that it can be resolved.

That is, by forming a specific packing coating layer in advance, workability during piping construction is greatly improved, and there is no problem of water contamination due to poor drying as seen with liquid sealants. The required torque during fitting, tightening, disassembly, and repair is as good as with raw tape. It has excellent sealing properties and pressure resistance, and has sufficient pressure resistance even when incompletely degreased. In particular, since the specific packing coating layer is firmly formed on the threaded portion, it has good return pressure resistance and can also achieve rust prevention effects. Thus, the present invention has been completed based on the above findings, and includes a packing coating layer having lubricity and sealing properties that is fixedly formed in advance on the threaded portion of a pipe joint having a thread. The present invention provides a new pipe joint with packing. The novel packing joint of the present invention has the following excellent features.

(1) The purpose of completely preventing rust on the threaded part of the joint can be achieved.

Currently, anti-rust oil is applied to the threaded parts, but long-term stock (
There are many cases where rust develops within about 3 years), and if left outdoors during construction, the product rusts and becomes unusable, causing leaks. In the present invention, since the threaded portion is coated, there is no rusting over a long period of time. (2) Provides perfect sealing effect.

Since 30 to 40% of the liquid sealing agent is a thickening agent, the evaporation amount causes meat thinning.

Since the packing coating according to the present invention has a volatile content of 0 (f), there is no leakage due to thinning of the material, and the pressure-resistant effect is exhibited immediately after piping. (3) Significant simplification and time savings.

The effort required to apply liquid sealant and spread raw tape during piping, drying after application, and curing time (more than 24 hours) before water is passed after construction is a huge waste.
According to the present invention, all of these problems can be solved.

(4) No special construction techniques are required.

There is no need to make any arrangements to prevent leakage or impact on water quality, such as the amount of liquid sealant applied, drying time, curing time, etc.

(5) Great contribution to pollution prevention and disaster prevention.

The evaporating agent in the liquid sealant contaminates the water quality or the atmosphere, and depending on the environment in which it is used, it may cause concerns such as fire, and may cause discomfort to the worker due to the odor. It can solve the problem.

(6) Easy to disassemble and repair.

Since all liquid sealants are of a fixed type, they completely solidify after the evaporation of the liquid sealant, which increases the return torque and makes them difficult to disassemble and must be cut after 3 hours or more.

With the heather invention, the torque during assembly and tightening remains unchanged, and even after installation, it is easy to disassemble and can be reused. (
7) It is possible to contribute to resource saving. Recovery of the liquid sealant is very difficult as it has to be carried out at the construction site and is therefore completely wasted.

In the present invention, when forming the packing coating layer,
Even if a municipal agent is used, it is easy to collect and can contribute to resource conservation. It is important for the pipe fitting of the present invention that the threaded portion is pre-coated with a specific packing coating layer.

Furthermore, it is important that the packing coating layer be firmly and tightly adhered to the threaded portion. It is useful for pipe fittings that typically have internal threads. Since the packing coating layer tightly covers the threaded portion, it also exhibits a sufficient rust prevention effect. In addition, it is important that the packing coating layer has lubricity so that joint pieces (for example, steel pipes with internal threads) can be easily fitted together during piping, and sealing properties that can prevent internal fluid leakage after tightening. It is.
The packing coating layer according to the present invention has lubricity and sealing properties as described above, and usually contains a solid lubricant.

Preferably, a packing coating layer consisting of a mixture of a rubber-like elastic binder and a solid lubricant is employed. The packing coating layer has a thickness of 300 microns or less, especially 50 microns or less.
It has a thickness of about 200 microns and is formed to cover the threaded part of the joint and firmly adhere. Further, the content of the solid lubricant may be selected from a range of about 30 to 80% by weight, preferably about 50 to 70% by weight, based on the weight of the entire packing coating layer. According to the present invention, a wide variety of binders can be used as the binder constituting the packing coating layer as long as it has rubber-like elasticity.

In consideration of heat resistance, chemical resistance, weather resistance, etc., which expand the range of applications of the joint, it is desirable to select fluorocarbon rubber as the binder. For example, propylene tetrafluoride ethylene copolymer, pnylidene fluoride hexafluoride propylene copolymer, tetrafluoroethylene perfluorovinyl ether copolymer, vinylidene fluoride trifluoroethylene chloride
/ type copolymer, vinylidene fluoride monopentafluoropropylene copolymer, perfluoroalkyl acrylate type elastomer, fluorine-containing ditroso type elastomer, fluorine-containing siloxane type elastomer, tetrafluoroethylene-ethylene-isobutylene type copolymer Polymers, ethylene-16-fluorinated propylene-based copolymers, tetrafluorinated ethylene-butene-11-based copolymers, tetrafluorinated ethylene-ethyl vinyl ether-based copolymers, fluorine-containing phosphonitrile-based elastomers, and the like. Of course, acrylic acid and its alkyl esters, vinylitene fluoride, propylene hexafluoride, chloroethyl vinyl ether, perfluoroalkyl vinyl ether, ethylene trifluorochloride, glycidyl vinyl ether, bromotrifluoroethylene, etc. may be added to the main components. A propylene tetrafluoroethylene copolymer containing propylene tetrafluoroethylene, or a fluoroethylene copolymer containing an appropriate amount of tetrafluoroethylene, perfluorovinyl ether, glycidyl pinylether, promotrifluoroethylene, etc. as the main component. It may also be a vinylidene chloride-16-propylene fluoride copolymer. mosquito\
Regarding fluoro rubber, Japanese Patent Publication No. 43-24199, U.S. Pat.
15987, JP 50-50488, JP 53-4115, JP 48-18957, JP 36-4390, JP 39-24
277 Publication, Special Publication No. 38-8591, Special Publication No. 3
See descriptions in JP-A No. 7-15922, JP-A-53-75290, and the like.

As for the solid lubricant constituting the packing coating layer, a wide variety of conventionally known solid lubricants can be employed.

For example, graphite, graphite fluoride, molybdenum disulfide, hard polyethylene, etc. can also be used, but polytetrafluoroethylene can be particularly preferably used in the present invention. The polytetrafluoroethylene may be fired or unfired, and may be a so-called fine powder obtained by emulsion polymerization or a so-called molding powder obtained by suspension polymerization. Also,
A compound having a high molecular weight as described above, U.S. Pat. No. 306
Specification No. 7262, Japanese Patent Publication No. 42-19252, Japanese Patent Publication No. 20782-1978, Japanese Patent Publication No. 52-24556
Wax-like or solid wax-like products obtained by telomerization as described in US Pat.
Publication No. 9, JP-A-48-21791, JP-A-48-1979
Wax-like or solid wax-like materials obtained by thermal decomposition or ionizing radiation irradiation decomposition methods as described in Japanese Patent No. 78252 may also be advantageously employed as the solid lubricant in the present invention.

Furthermore, the solid lubricant made of polytetrafluoroethylene may contain a small amount of a copolymer component or a modifying agent as well as the telogen terminal group used in the telomerization. In the present invention, it is desirable that the solid lubricant as described above be dispersed and mixed in the packing coating layer as uniformly as possible, and usually in the form of fine particles, fine fibers, powder, or particles. It is preferable that it be adopted.

For example, the average particle size is 100 microns or less, preferably 5 to
It is used in powder form of about 30 microns. In addition, the binder having rubber-like elasticity is desirably a room-temperature curing type, considering workability during coating formation, which will be described later.
For example, Japanese Patent Application Laid-Open No. 53-75290 and Japanese Patent Application No. 53-7
Fluororubbers copolymerized with glycidyl vinyl ether as described in the specification of No. 2052, etc., or fluororubbers prepared at room temperature curing type by vulcanization compounding, etc.
It can be particularly suitably employed. There is no particular reason to limit the means for forming the specific packing coating layer as described above, but in the present invention, as described above, the method of forming the specific packing coating layer is such that the threaded portion of the joint is coated with the threaded portion and adhered in an adhesive state. It is important that a specific packing coating layer is formed. The following items are listed as quality targets for the specific packing coating layer. (a) When joining joint pieces to a joint, the screws must be tightened smoothly.

(Lubricity) (b) The packing layer covering the threaded part of the joint must maintain its anti-corrosion effect for a long period of time (3 years or more).

(Adhesion) (c) Packing coating layer material should not affect water quality.

(d) When the joint pieces are joined to the joint, the pressure resistance is 50
k9/(-F7l or more, 90, pressure resistance after returning to 20k9/d or more.

(Sealability) (e) Ease of disassembly and repair. (Lubricity) When forming a specific packing coating layer,
A method that can be suitably employed is to apply a liquid composition containing a solid lubricant and a binder having rubber-like elasticity as described above to the threaded part of the joint, dry it, and harden it by heat treatment or the like as required. . The liquid composition may contain appropriate additives within a range that does not impede the effects of the present invention. Examples include coloring agents such as pigments, adhesion improvers to screw parts, vulcanizing agents for vulcanizing the rubber-like elastic binder, vulcanization aids, and various fillers. Usually, the viscosity most applicable to industrial practice (1000-100
00 centipoise), solids concentration (20-80 wtl!)
)) and the like are suitable.

In order to form a specific packing coating layer using a liquid composition such as the one described above, it is necessary to spray the maximum amount that can provide sufficient and long-term rust prevention effect, and the minimum amount that can provide sealing and lubrication properties. Canning, drying and curing to form a coating layer.

The packing coating layer is formed by sufficiently degreasing the threaded part of the joint pipe with acetone or trichlorethylene, and then applying the liquid composition to a predetermined thickness by spraying or... After drying to such an extent that no stickiness is removed in step ``C'', a method may be suitably employed in which a heat treatment is performed for 10 to 20 minutes in a heating oven at 80 to 1800 C to form a fixed coating layer. In the thus obtained packing joint of the present invention, a coating layer having lubricating properties and tool properties is already formed on the threaded portion, so it can be used without worrying about various troubles that occur at piping construction sites. By simply fitting and tightening, you can achieve a complete seal, immediate water flow, and the purpose of water supply without much effort.

The advantages of the packing joint of the present invention at piping construction sites will be further described as follows. In other words, when using a conventional liquid sealant, in order to ensure sufficient adhesion of the liquid sealant, it is necessary to completely remove the cutting oil that accompanies the cutting process of the threaded part, which is extremely difficult to work with. It has become a tedious task. In comparison, if the packing joint of the present invention is used, such work will not be necessary at all, and there will be no need to worry about skill in construction techniques and curing methods, and the construction time will be greatly reduced. It is also possible to shorten the length. Needless to say, the joint with packing of the present invention has made an extremely large contribution to the industry, with absolute certainty against leakage, reliability in preventing water pollution, ease of disassembly and repair, and reusability of joints and steel pipes. be. Next, the effects of various conditions for water supply of the joint with packing of the present invention will be explained, and the results will be explained in comparison with typical commercially available liquid sealants and raw tapes.

In the following tests, the following packing joints of the present invention were used. That is, 100 parts by weight of an elastomer of tetrafluoroethylene/propylene/glycidyl vinyl ether terpolymer with a molar ratio of 55/43/2 and a molecular weight of 60,000, and a molecular weight of 10,000 lowered by radiation irradiation. Polytetrafluoroethylene powder 25 with a particle size of 15 microns
A coating with a thickness of 150 microns was formed on a threaded portion of a pipe joint having an internal thread using a liquid composition prepared by adding and mixing 0 parts by weight of ethyl acetate to 600 parts by weight of ethyl acetate. To form the coating, spray the composition onto the threaded part,
By curing for 10 minutes at a temperature of 80℃? The agent was allowed to evaporate. Preliminary treatment for ordinary piping using sealant, liquid sealant, and raw tape was performed in the following order. 1. Degrease the rust preventive oil from the threaded part of the joint.

2. Degrease the cutting oil from the steel pipe threads.

3. Apply rust prevention treatment to the back 2 to 3 threads of the joint thread.

4. Treat the end face of the steel pipe with anti-corrosion treatment.

5. If using an anti-corrosion liquid sealant, apply it to the end face and all threaded parts for 3 to 5 minutes. After the agent has evaporated, they fit together.

(A) Comparison of settling time before mating (experimental values using 2-inch joints and steel pipes, the same applies hereinafter) (I3) Lubricity Maximum torque per 1360° rotation: Single (C) Distillation (completely degreased) ) After cleaning the rust preventive oil on the joints and the cutting oil on the steel pipes with trichlorethylene, liquid sealant and raw tape were applied or spread.

The pressure resistance was measured after 6 rotations of 36'' in the above (B). The above values are the average values of 10 tests.

In addition, for liquid sealants, the values are the average values of four typical commercially available products, and in the case of liquid sealants, the values are measured after curing for 24 hours after tightening. D) Pressure resistance (incomplete degreasing) For complete degreasing in 0 above, after simply wiping off the rust preventive oil and cutting oil from both the joint and the steel pipe using a rag, a test piece was prepared according to C). The pressure resistance was tested.

(8) Resistance to pressure after return An assembly was prepared according to the pressure resistance described in C) above, and after the following time period had passed, the pressure resistance after rotation was measured.

[F] Restoration torque property (ease of disassembly and repair) 0 above
An assembly was made that conformed to the pressure resistance of , and after curing for one week, the maximum torque required for disassembly 9' and return rotation was measured.

However, the final torque when assembling and tightening is 2000k9-? It is. Next, the results of a comparative test on the adhesion, rust prevention, and water quality of the packing coating layer and liquid sealant will be explained. A sample was coated on the surface and dried and heated as described in (1)-(a).

(1)-(c) Dupont impact test According to JIS K54OO-6.13 impact resistance method B.

Ball diameter 1 inch, load 5009, falling distance 50Cr11,
The test piece conformed to (1)-(a). (1)-(d) Bending test Mild steel plate (PL9O x 90 x 1, 2)
A test piece that had been dried and heated according to 1)-(a) was bent 180 degrees.

(1)-(e) Abrasion resistance test According to JIS K69O2 thermosetting resin cosmetic provisional test method.

The number of revolutions is 1000, the grindstone used is CS-17, and the test piece is (1).
- According to (a).

(2) Rust prevention test (2)-(a) Salt spray test According to JIS Z237L salt water spray test 1 test method.

The test was conducted continuously, and the period until rust was observed was measured. Test 1 test piece is resin coated joint elbow 3/4
An inch tube was cut in half, the threaded portion was coated with the sample, and the tube was air-dried for 48 hours. (2)-(B) Salt water immersion test A test piece based on (2)-(A) was used and was immersed in a constant temperature bath (5'C) of 3% salt water.

The test period was 6 months, and the presence or absence of rust was checked every month during that period. (2)-(c) Flowing water test specimen is resin coated joint elbow 3/4 inch pipe,
Each sample is a 3/4-inch socket pipe made of hard vinyl chloride resin-lined steel pipe in a U-shape.

The water flow was started under two conditions: 2 hours after piping and 24 hours after piping.

The coating of the sample was done with machine oil still on it. It is determined whether the sealant applied to the threaded part and the threaded end flows out when water is passed through it, and those that do not flow out are considered to be passed. If leakage is observed, it will be marked as a flow and will be rejected. (3) Water quality test 5 x 15 CTrL glass Temporarily put both sides of the sample together and 10,0
A test piece was prepared by uniformly applying the coating to ~ and drying it at room temperature for 24 hours.

After washing the Test 1 test piece with running water for 1 hour, it was immersed in distilled water 11 prepared in advance, and after being left for 24 hours, the test piece was taken out. As a characteristic test, odor, taste, potassium permanganate consumption, and phenol content were investigated in accordance with the Japanese Association of Japan (Japanese). Example 2 30 parts by weight of low molecular weight polytetrafluoroethylene powder, molecular weight 10,000, average particle size 15 microns, was added to 100 parts by weight of fluoro rubber paint Perflon 9 (manufactured by Kinyosha) stock solution (solid content concentration 35wt01). Parts by weight were added and thoroughly stirred using a homomixer to homogenize the mixture.

Thereafter, Perflon 8 curing agent (manufactured by Kinyosha Co., Ltd.) was added to the stock solution containing polytetrafluoroethylene powder and stirred to prepare a paint that could be cured at room temperature. Using this liquid composition, the threaded part of a pipe fitting with an internal thread is coated with a thickness of 1.
A coating of 0.00 microns was formed.

To form the coating, the composition was applied to the threaded portion with a brush and cured at a temperature of 50° C. for 24 hours to evaporate the additive and harden to form a fixed coating layer. The maximum torque value per 360° rotation required for male thread fitting using the packing joint (2 inch joint pipe) according to this example is 0 to 5 kg for the first rotation? , 6th rotation 1600-18
00k9-α, and the water pressure after sleep is 100k9/
It is ~. In comparison, a joint with packing using a liquid composition without the addition of polytetrafluoroethylene powder is difficult to fit. Example 3 Composition ratio (mole ratio) of vinylidene fluoride/propylene hexafluoride/tetrafluoroethylene/glycidyl vinyl ester
-69/12/17. /2, polytetrafluoroethylene low molecular weight powder, molecular weight 10,000, average particle size 8 microns for 100 parts by weight of polymer with molecular weight 45,000 10
Using a liquid composition consisting of 0 parts by weight and 300 parts by weight of methyl ethyl ketone, a coating layer with a thickness of 200 microns was formed on the threaded part of a 2-inch pipe having a female thread.

The lubricity during fitting of a joint with a fixed coating layer formed by 1000CX dry curing for 10 minutes is equivalent to that of raw Teflon 8 tape, pressure resistance is 100 kg/d, and pressure resistance is 50.
kg/d or more.

Claims (1)

[Scope of Claims] 1. A packing joint characterized in that a packing coating layer containing fluororubber and polytetrafluoroethylene is fixedly formed in advance on a threaded part of a pipe joint having threads, covering the threaded part. . 2. The joint with packing according to claim 1, wherein the packing coating layer has a thickness of 300 microns or less. 3. Claim 1, wherein the content of polytetrafluoroethylene in the packing coating layer is 30 to 80% by weight.
Fitting with packing as described in section. 4. The joint with packing according to claim 1, wherein the pipe joint has a female thread.