JP2000063798A - Permeable liquid sealing agent for piping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable quick mending of a gas-leaking part without stopping the flow of a gas in a piping by applying the objective permeable liquid sealing agent composed mainly of a specific emulsion to the inside of the joint of the gas-transferring piping. SOLUTION: The objective sealing agent composed mainly of an emulsion having specific particle diameter and compounding ratio, preferably an aqueous emulsion of an acrylic copolymer is applied to the joint part of a gas- transferring piping from the inside of the piping. The emulsion contains (A) 55-85 wt.% of particles having diameter of 0.1-2.0 μm, (B) 5-35 wt.% of particles having diameter of 2.0-10.0 μm and (C) <=10 wt.% of other particles. The above emulsion preferably contains 20-80 wt.% of solid component and 80-20 wt.% of solvent. Preferably, the viscosity of the sealing agent is 50-250 cps at 23 deg.C and the thixotropy ratio is 1.1-2.0.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid permeable pipe sealant for use in a portion where gas leakage easily occurs, such as a joint portion or a branch portion of a pipe for transferring gases such as fuel gas. The present invention relates to a liquid permeable pipe sealant which is used by permeating a fibrous filler such as hemp used as a sealant at a joint between pipes (pipe joint).

[0002]

2. Description of the Related Art Conventionally, in a pipe for transferring gas, a fibrous filler such as hemp is sandwiched or filled at a seam of a pipe joint as a gas leakage preventing means at a joint portion (pipe joint portion) between pipes. Then, for example, a liquid sealing agent containing rubber latex as a main component as described in JP-A-55-86859 was permeated and impregnated for sealing. Further, since the gas transferred in the pipe, especially the fuel gas, contains a large amount of water in the gas, these moisten and expand the fibrous filler used in the pipe joint portion, and Hermetic seal was made more secure.

However, since the water contained in the fuel gas has a disadvantage of corroding the inner surface of the pipe, in recent years, the water in the gas has been removed and transferred in a dried state. It was Therefore, the supply of moisture from the passing gas cannot be received, the fibrous filler used in the pipe joint section described above dries and becomes thin, and a gap is created between the fibers to allow the gas to flow from the joint section. The problem of leaking has begun to occur.

[0004]

As a method for repairing the leakage of gas from such a joint portion, for example, a method of atomizing a liquid sealing agent and sending it to a repaired portion (Japanese Patent Laid-Open No. 1-1999)
153900) and the live tube repair method (method of repairing without stopping gas supply) as described in Japanese Patent No. 2609149 have already been proposed. Since these methods are basically methods of repairing the leaked part without stopping the gas transfer, rapid penetration of the leaked part, that is, the pipe joint part into the fibrous filler, and high filling property (sealability). However, none of the conventional sealants have sufficiently satisfied these performances.

Therefore, the present invention provides a liquid permeable pipe sealant for promptly repairing a gas leak portion, on the premise that repair work is performed without stopping the transfer of gas in the pipe. To aim. In particular, it is to provide a liquid permeable pipe sealant which forms a film excellent in permeability due to capillarity to a fibrous filler used in a joint portion and also excellent in gas impermeability. .

[0006]

The present invention provides a liquid sealant for repairing a joint portion of a pipe for transferring gas from the inside of the pipe, wherein the liquid sealant has the following particle size and compounding ratio (solid content). The above-mentioned problems have been solved by using the constituted emulsion as the main component. (A) Particle size 0.1 to 2.0 μm 55 to 85% by weight (B) Particle size 2.0 to 10.0 μm 5 to 35% by weight (C) Other particle size 10% by weight or less

As the emulsion constituting the liquid permeable pipe sealant of the present invention, a copolymer such as polyvinyl acetate type, acrylic type, synthetic rubber type, polyvinylidene chloride type, silicone type, urethane type or fluorine type copolymer is used. Those obtained by emulsion polymerization in a water solvent can be mainly used, but the method for producing the emulsion and the like are not particularly limited, and conventionally known methods (JP-A-62-241903 and JP-A-4) are used.
No. 165000, JP-A-8-302239, etc.) can be used. In addition, in view of recent problems of environmental pollution, it is preferable to use an aqueous emulsion using water as a solvent, but in consideration of the internal corrosiveness of piping, a non-aqueous emulsion using an aliphatic hydrocarbon as a solvent is also used. It is possible.

Of these various emulsions, an acrylic copolymer aqueous emulsion is particularly preferable. Specific examples of the acrylic copolymer include two-component, three-component and four-component copolymers composed of (meth) acrylic acid ester, styrene, (meth) acrylic acid, acrylonitrile and the like. To be

The particle size and blending ratio (solid content) of various emulsions in the present invention are (A) particle size of 0.1 to 2.0 μm.
/ (B) particle size 2.0 to 10.0 μm / (C) other particle size = 55 to 85% by weight / 5 to 35% by weight / 10% by weight or less. The particle size of (A) is 0.2 to 0.4 μm and the particle size of (B) is 2.4 to 0.4 μm.
More preferably, it is 8.0 μm. Then, the above-mentioned (A) particle size of 0.1 to 2.0 μm / (B) particle size of 2.0
It is preferable that the compounding ratio of ˜10.0 μm / (C) and other particle diameters is further 60 to 80% by weight / 10 to 30% by weight / 10% by weight or less. It is preferable to use the same kind of emulsions having different particle sizes, but it is also possible to mix and use different kinds of emulsions as long as the mixed composition is stable.

Among the emulsions of the present invention, (A) the emulsion having a particle size of 0.1 to 2.0 μm penetrates into the gaps between the fibers of the filler of the joint portion and fills the minute gaps. Also, (B) particle size 2.0 to 10.0 μm
The emulsion of prevents the liquid permeable pipe sealant from getting caught between the fibers of the filler and slipping through between the fibers, and forms a resin layer on the surface of the fibrous filler to allow gas permeation. Play a role in preventing Therefore, if the compounding ratio of (A) the emulsion having a particle size of 0.1 to 2.0 μm is too large, or if the emulsion having a particle size smaller than this is blended in an amount of more than 10% by weight, the liquid permeable pipe seal is formed. The agent slips between the fibrous fillers,
It is not possible to form an effective non-permeable film on the surface of the filler. On the contrary, (B) particle size 2.0 to 10.0 μ
If the amount of the emulsion of m is too large, or if the emulsion having a particle size larger than this is mixed in an amount of more than 10% by weight, the capillary action on the fibers of the filler is suppressed and the liquid permeable pipe sealant is The fibrous filler does not reach the entire area and the repair effect is reduced.

The ratio of the solid content to the solvent in these various emulsions varies depending on the type of the compound that forms the basis of the emulsion, for example, the acrylic copolymer in the case of an acrylic emulsion, but it is generally in the range that can exist as an emulsion, that is, The ratio of the solid content to the solvent is arbitrarily determined within the range of 20 to 80% by weight of the former and 80 to 20% by weight of the latter.

Further, the liquid permeable pipe sealant used in the present invention has a viscosity at 23 ° C. of 50 to 2 in consideration of the coating property to the inside of the pipe and the permeable filling property to the fibrous filler.
It is preferably 50 cps, more preferably 8
It is in the range of 0 to 160 cps. Further, when the liquid permeable pipe sealant is applied to the inner surface of the pipe, it is also effective to impart thixotropy in order to suppress the dripping from the applied part to some extent (to the extent that the permeability is not hindered). In this case, the effective thixo ratio (determined from the viscosity ratio at 2 rpm and 20 rpm using a BL type rotational viscometer according to JIS-K 7117) is particularly effective in the range of 1.1 to 2.0, and It is preferably 1.1 to 1.5.

[0013]

In the present invention, by combining emulsion particles having different particle diameters, the fibrous filler used for sealing the joint portion of a pipe such as a gas pipe is efficiently impregnated and filled in the gap. The gap between the fibrous fillers is blocked to prevent gas permeation, and a resin film is formed on the surface of the fibrous fillers to further prevent gas from entering the inside of the fibrous fillers.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in detail with reference to Examples. (1) Manufacture of Liquid Permeable Pipe Sealing Agent Each component was mixed and stirred in the proportions shown below to produce each liquid permeable pipe sealing agent. In addition, for the production of acrylic emulsion of each particle size, for example, various acrylic monomers are emulsified in water together with a catalyst, and then heated to polymerize the monomers to form a polymer to form an emulsion. At this time, if a large amount of emulsifier is present in the system from the beginning, the particles will become fine, and if the emulsifier is added little by little to the system, the particle size will increase, so this property is used to adjust the particle size of the acrylic emulsion. While manufactured.

The acrylic emulsion (A1) shown in Table 1 has a thickness of 0.1 to 0.4 μm, and the acrylic emulsion (A2) has a thickness of 0.4 to 1.5 μm. Is 1.5 to 2.2 μm, acrylic emulsion (B1) is 2.2 to 10.0 μm
Of acrylic emulsion (C1) is 10.0-2
It has a respective particle size of 0.0 μm. In addition, chloroprene and Teflon type emulsions were used as the base resins of Examples 5 to 7. Furthermore, if necessary, a foam stabilizer,
Wetting penetrants, water and oil repellents, and fillers were added.

A detailed description will be given below with reference to examples and comparative examples. The parts and percentages in this example are by weight unless otherwise specified.

[Example 1]       Acrylic emulsion (A1) 70.0 parts       (50% solid content, particle size 0.1-0.4 μm)       Acrylic emulsion (B1) 30.0 parts       (Solid content 50%, particle size 2.2 to 10.0 μm)       Foam stabilizer (Nopco DC-100A, manufactured by San Nopco) 3.0 parts       Wetting Penetrant (NeoPerex F-65 manufactured by Kao Corporation) 0.5 part

[0017]

Example 2       Acrylic emulsion (A2) 80.0 parts       (50% solid content, particle size 0.4-1.5 μm)       Acrylic emulsion (B1) 20.0 parts       (Solid content 50%, particle size 2.2 to 10.0 μm)       Foam stabilizer (Nopco DC-100A, manufactured by San Nopco) 3.0 parts       Wetting Penetrant (NeoPerex F-65, manufactured by Kao Corporation) 0.5 part

[0018]

Example 3       Acrylic emulsion (A1) 80.0 parts       (50% solid content, particle size 0.1-0.4 μm)       Acrylic emulsion (B1) 15.0 parts       (Solid content 50%, particle size 2.2 to 10.0 μm)       Acrylic emulsion (C1) 5.0 parts       (50% solid content, particle size 10.0 to 20.0 μm)

[0019]

Example 4       Acrylic emulsion (A1) 50.0 parts       (50% solid content, particle size 0.1-0.4 μm)       Acrylic emulsion (A2) 20.0 parts       (50% solid content, particle size 0.4-1.5 μm)       Acrylic emulsion (A3) 20.0 parts       (50% solid content, particle size 1.5 to 2.2 μm)       Acrylic emulsion (B1) 10.0 parts       (Solid content 50%, particle size 2.2 to 10.0 μm)       Wetting Penetrant (NeoPerex F-65, manufactured by Kao Corporation) 0.5 part

[0020]

Example 5       Neoprene latex 70.0 parts       (Solid content 47%, particle size 0.3 μm)       Acrylic emulsion (B1) 30.0 parts       (Solid content 50%, particle size 2.2 to 10.0 μm)       Water and oil repellent 5.0 parts       (Dickguard F-90 manufactured by Dainippon Ink and Chemicals, Inc.)       Filler 0.3 parts       (Aeroziel # 200 made by Degussa Japan)

[0021]

Example 6 A low molecular weight tetrafluoroethylene resin fine particle was prepared by dispersing it in an emulsion or latex using a dispersion prepared by dispersing it in water. Neoprene latex 100.0 parts (solid content 47%, particle size 0.3 μm) Neoprene latex 45.0 parts (solid content 45%, particle size 3.0 μm) Dispersion of low molecular weight tetrafluoroethylene resin 125.0 parts (Lubron LDW-10 manufactured by Daikin Industries, Ltd. (solid content 10%, particle size 0.15 μm) Water- and oil-repellent agent 5.0 parts (Dickguard F-90, manufactured by Dainippon Ink and Chemicals, Inc.) Filler 0.3 parts (Aerogel # 200 Degussa Japan Ltd.)

[0022]

[Comparative Example 1]       Acrylic emulsion (A1) 100.0 parts       (50% solid content, particle size 0.1-0.4 μm)

[0023]

[Comparative Example 2]       Acrylic emulsion (C) 100.0 parts       (50% solid content, particle size 10.0 to 20.0 μm)

[0024]

[Comparative Example 3]       Acrylic emulsion (A1) 70.0 parts       (50% solid content, particle size 0.1-0.4 μm)       Acrylic emulsion (C1) 30.0 parts       (50% solid content, particle size 10.0 to 20.0 μm)       Foam stabilizer (Nopco DC-100A, manufactured by San Nopco) 3.0 parts       Wetting Penetrant (NeoPerex F-65, manufactured by Kao Corporation) 0.5 part

[0025]

[Comparative Example 4]       Neoprene latex 100.0 parts       (Solid content 47%, particle size 0.3 μm)       Water and oil repellent 5.0 parts       (Dickguard F-90 manufactured by Dainippon Ink and Chemicals, Inc.)

(2) Evaluation (Physical Properties, etc.) Each of the liquid permeable pipe sealants produced in (1) above was evaluated as follows, and the results are shown in Table 1. ． A vinyl chloride pipe having an inner diameter of 16 mm is filled with 6 g of hemp and compressed to a height of 5 cm. Various liquid permeable pipe sealants were applied to this test piece at 2.3 kPa (230 mm).
H ₂ O) pressure injection for 5 minutes. The permeation height at this time was measured with a caliper. ． Airtightness A vinyl chloride pipe having an inner diameter of 16 mm is filled with 6 g of hemp and compressed to a height of 5 cm. Various liquid penetrating pipe sealants are pressure-injected into this test piece to make penetration of 4 cm. Then, in a constant temperature bath at 25 ° C, 2.3 kPa (230
(mmH ₂ O) was kept under pressure for 1 month, 2 months, 3 months, and the presence or absence of leakage was observed. ． The bending angle of the bending vibration joint part was set to θ = 0.05 ° so that the liquid permeable pipe sealant layer was repeatedly subjected to strain of about 5.7%. It is 140 times by bending vibration 5 times per second.
The durability was observed when the test was repeated 10,000 times. This is equivalent to a 30-year wheel load on a national highway.

[0027]

[Table 1] Penetration: ○, 1.0-
1.5 cm was evaluated as Δ and less than 1.0 cm was evaluated as x. Airtightness: No leakage was evaluated as ○, and leakage was evaluated as ×. Flexural vibration: No leakage during 1.4 million bending vibrations and after vibration stopped ○, There was a small amount of leakage during 1.4 million bending vibrations, but leakage stopped after vibration stopped △, 140
Those that leaked during the bending vibration of 10,000 times and after the vibration stopped were rated as x.

[0028]

EFFECTS OF THE INVENTION When the composition of the present invention is used, a joint portion or a branch portion of pipes for transferring gases such as fuel gas,
The resin composition of the present invention quickly permeates into a fibrous filler such as hemp used in a portion where gas is likely to leak, particularly in a pipe-to-pipe joint portion (pipe joint portion) to ensure airtightness. be able to. For this reason, it can be said that the liquid permeable pipe seal is particularly suitable for the method of repairing the leaked portion without stopping the gas supply.

Claims (4)

[Claims] 1. A liquid sealant for repairing a joint portion of a pipe for transferring gas from the inside of the pipe, wherein the liquid sealant is mainly composed of an emulsion composed of the following particle size and compounding ratio (solid content). Liquid penetrating pipe sealant. (A) Particle size 0.1 to 2.0 μm 55 to 85% by weight (B) Particle size 2.0 to 10.0 μm 5 to 35% by weight (C) Other particle size 10% by weight or less 2. The liquid permeable pipe sealant according to claim 1, wherein the emulsion is an acrylic emulsion. 3. The viscosity of the sealant is 50 to 250 cp.
The liquid permeable pipe sealant according to claim 1, which is s. 4. The thixo ratio of the sealant is 1.1 to 2.
The liquid permeable pipe sealant according to claim 1, which is 0.