JPS616481A - Ductile cast iron pipe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ductile cast iron pipe whose porosity has been repaired with a special resin.

The inner surface of the socket part of the cast iron pipe cast by applying centrifugal force, especially the cast iron with a protrusion formed on the inner surface of the socket part, such as the joint type T type specified in JIS G5526r Ductai μ Cast Iron Pipe. In a pipe, since the cooling rate is different, cavities are likely to occur on the surface of the protrusions. The method of repairing the blow hole was to fill the small corner part with welding and sanding and to make it flat. In addition, Jl5G5526-1982 newly added that the use of epoxy resin fillers is also permitted with the approval of the orderer.

The purpose of the present invention is to develop an epoxy resin filler that cures at room temperature and has excellent workability, which is suitable for repairing blowholes that occur during the production of cast iron pipes, and to provide ductile cast iron pipes that can be repaired using this epoxy resin filler. It's about doing.

Examples of requirements for the filling material for repairing blow holes according to the present invention are as follows.

1. Adhesion (adhesion) to spheroidal graphite cast iron (Ducta IN cast iron)
be of good quality.

2. The resin has a viscosity that allows the resin to penetrate into recesses with a diameter of 0.5 to 10 tl, a depth of O', and a variety of shapes and sizes of 5 to 3 vR, and the resin that has penetrated hardens quickly. No sagging.

3. At any time of low temperature in winter or high temperature in summer,
Even if the inner surface of the pipe is wet after washing with water, it can be easily applied and filled, and it cures and has excellent adhesion.

4. The cured resin sufficiently fills and adheres to the bow-A recess without volumetric shrinkage, and watertightness that passes the water pressure test can be guaranteed for a long period of time.

5. The cured resin does not dissolve in water and has no adverse effect on water quality, and meets the Japan Water Works Association standard JWWAK7115 r.
It must have the same performance as "Tar epoxy resin paint coating method for water supply".

6. The cured resin can be easily cut with a sander to create a smooth surface.

7. The cured resin must have visibility that can pass the pipe flatness test specified in JIS G5526.

8. The cured resin must have adhesion to tar-based paint, cool epoxy resin, or zinc-rich paint for internal coating.

On the other hand, there are various types of epoxy resin fillers, and it is known that the properties and performance can vary depending on the type of hardening agent. Filling materials that can be obtained have also been developed, but a filling material that satisfies all of the requirements can be achieved for the first time by using the filling material according to the present invention.

According to the present invention, the blow holes on the inner surface of the socket part of a ductile cast iron pipe are repaired with a filler containing a liquid epoxy resin/liquid polysulfide polymer/tertiary amine composition as a main component and an extender pigment mixed therein. This is a 1v cast iron pipe.

The ductile cast iron pipe in the present invention is J I 5G552
6 "Ductile cast iron pipe", JIS G5527 "Ductile cast iron irregularly shaped pipe" and JISA5314 r on the inner surface of the pipe
Waterworks, sewerage systems, etc. with mortar lining applied to "centrifugal force spheroidal graphite cast iron pipes for waterworks"
Refers to cast iron pipes used for industrial water supply, agricultural water supply, etc. Liquid epoxy resin is general-purpose bispheno-1v
A, Bispheno-/l/F1 lid! acid, resorcinol,
It refers to a resin having two or more epoxy groups obtained by condensation reaction of P-oxybenzoic acid, polyethylene glyco-p1 polypropylene glyco-μ, etc. and epichlorohydrin. Epoxy resins are suitable. When the epoxy equivalent is greater than 400, penetration into small recesses is insufficient, leading to a decrease in adhesive strength. The liquid polysulfide polymer is used as a curing agent that also serves as a sinterability imparting agent for epoxy resins having mercaptan groups such as polysulfite resins, aromatic polythio-μ, and thioester resins. Among these, polysphite resin is optimal in terms of physical properties of the cured product. In addition to being used as epoxy resin curing agents, tertiary amines such as dimethylcyclohexylamine, dimethylbenzylamine, dimethylhexylamine, dimethylaminomethylphenol, dimethylamino P-cresol, pyridine, α-picoline, piperidine, etc. It is used as a curing accelerator for liquid polysulfide polymers. Among these, dimethylaminomethylphenol is optimal in terms of curing properties.

Next, the blending ratio of liquid epoxy resin: liquid polysulfide polymer: tertiary amine is 100:10 to 100:10 in terms of solid content weight.
It is determined as appropriate depending on the performance required in 20021-20. That is, when visibility is required, a large amount of liquid polysulfide polymer is blended, and when rigidity is required, a small amount is blended. The amount of tertiary amine blended varies depending on the amine equivalent of each amine, but the relationship with the epoxy equivalent in the epoxy resin is epoxy equivalent/amine equivalent = 1/
1.1 to 0.9 is appropriate. Next, extender pigments include, in addition to bulking inorganic fillers such as silica, calcium carbonate, and barium sulfate, anti-sagging agents such as anhydrous or water-containing fine particle silicic acid, and colored pigments such as titanium white. The amount of extender pigment mixed is 1 to 1 in weight ratio to the composition.
It is determined as appropriate depending on the performance required for the 00 part. To mix these components into a filler, the epoxy resin as the main component and the tertiary amine as the curing agent component are placed in separate containers, and the liquid polysulfide polymer and extender pigment are placed in either the main component or the curing agent. It is customary to mix one or both of them and store them, and just before use, mix the main component and the curing agent component before use. Further, the work of coating and filling the casting hole is performed using an applicator such as a spatula, trowel, or brush.

The filler according to the present invention satisfies the above requirements 1 to 8.
As a result, repair of blowholes is much easier than with conventional welding methods, resulting in a perfect wall finish. In addition, other epoxy resin fillers such as polyamide,
Even when room-temperature curing agents such as aliphatic amines, aromatic amines, and various amine adducts are used, the adhesion to ductile cast iron surfaces, penetration into small dents, curing properties, and flexibility of cured resins are maintained. However, the filler according to the present invention is characterized in that it does not cause any problems, such as adverse effects on water quality and recoatability of top coats. For example, fillers using aliphatic amine-based or aromatic amine-based curing agents may have an adverse effect on the flexibility of the cured resin and on water quality (
There is a problem in that unreacted residual amine dissolves in water), and fillers using polyamide-based and amine adduct-based hardeners have poor adhesion to small recesses and adhesion to internal coatings. Problems arose due to negative effects on water quality.

Next, the present invention will be explained using examples. Parts indicate parts by weight.

Example 1 80 parts of bispheno-1A type epoxy polysulfide resin with an epoxy equivalent weight of 190 and dimethylaminomethylpheno-Iv
IO club and heavy leg strength! A mixture with 60 parts of v was used as a curing agent component. A filler was prepared by mixing 100 parts of a molten component and 100 parts of a curing agent component.

Comparative Example 1 The main ingredient was the same as in Example 1, and a mixture of 100 parts of a polyamide resin with an amine value of 300 and 50 parts of heavy carbonaceous was used as the curing agent.

A filler was prepared by mixing 100 parts of the main ingredient and 100 parts of the curing agent.

Comparative Example 2 The main ingredients were the same as in Example 1, and a mixture of 50 parts of an amine adduct with an amine value of 450 and 25 parts of heavy coal was used as the curing agent.

A filler was prepared by mixing 100 parts of the main ingredient and 50 parts of the curing agent.

Next, the filler of Example 1 and Higa Examples 1 and 2 was filled with a spatula into a small recess (cast hole) on the inner surface of the socket of a T-shaped Dakukui/L' cast iron pipe with a nominal diameter of 800. After being allowed to stand at room temperature for one month to cure, it was subjected to the next test.

b) Adhesion-1: Subject to flattening test specified in JIS G5526 to determine whether the filled repaired part peels off from the pipe surface and whether the filler material cracks.

Mouth) Adhesion with paint: Tar Epoquin resin for internal coating,
Zinc-rich paint is spray applied, dried and hardened, then subjected to a goblin test.

Separately from this, Adhesiveness-2: As shown in Figure 1, a filler was applied to a piece of ductile cast iron (5ax x 5a square, thickness l'ctn) so that the adhesive layer thickness was 1 g. After being allowed to stand at room temperature for one month to harden, the tensile strength is measured.

2) Water quality test: The water quality test stipulated in the Japan Water Works Association standard JWWAK115 was judged to have passed or failed.

The results of these measurements are shown in Table 1.

[Brief explanation of the drawing]

FIG. 1 shows a diagram for testing the tensile strength of a pot for measuring adhesion. Arrows indicate the direction of tension. 1. (1-...Gukutai A/cast iron piece 2,2-...
・-Tension rod 3・・・Filler patent applicant AIKanigyo Co., Ltd. Kubota Iron Works Co., Ltd. Figure 7

Claims (2)

[Claims] (1) The porosity on the inner surface of the socket of the ductile cast iron pipe is repaired with a filler containing a liquid epoxy resin/liquid polysulfide polymer/tertiary amine composition as the main component and an extender pigment mixed in. A ductile cast iron pipe characterized by: (2) The ductile cast iron pipe according to claim 1, wherein the liquid epoxy resin is a resin having an epoxy equivalent of 400 or less, the liquid polysulfide polymer is a polysulfide resin, and the tertiary amine is dimethylaminomethylphenol.