JPS6047087A - Primer composition for pipe lining - Google Patents

Abstract

PURPOSE:To provide the titled primer compsn. contg. a specified (meth)acrylate in a specified amt. and exhibiting excellent penetration, surface curing property and resistance to cracking. CONSTITUTION:The primer compsn. consists of (A) a monomer mixt. comprising 70-90wt% (a) dicyclopentenyl(meth)acrylates and/or dicyclopentenyloxyalkyl (meth)acrylate, 10-200wt% (b) glycidyl (meth)acrylate and 0-20wt% (c) other alkyl (meth)acrylates, with the sum of (b) and (c) accounting for 10-30wt% and (B) a catalyst in an amt. to cause oxidative curing of the mononer. As the dicyclopentenyl (meth)acrylate and dicyclopentenyloxyalkyl(meth)acrylate contain auto-oxidative functional groups, the primer compsn. has an excellent curing property and is not affected adversely by oxygen in the air even when a peroxide catalyst is used.

Description

Detailed Description of the Invention The present invention provides a method for lining the inner surface of a pipe made of cast iron or the like used for transporting gas, liquid, powder, etc., or a method for press-fitting a lining material into a pipe joint. An undercoat composition for treatment that has permeability, surface hardening properties, and crack resistance and is used for the purpose of impregnating dust, etc. present at the bottom of piping, fixing this dust, etc., and forming a base film on the inner surface of the piping. The present invention relates to an undercoat composition for pipe lining that has excellent properties.

Piping such as gas piping and water piping usually transports the contents under pressure, but leaks may occur from the joints due to vibrations such as automobiles or earthquakes, or due to long-term use, or leaks due to corrosion of the piping body. may occur. Conventionally, as a repair method for joints and corroded parts that are causing such leaks,
Methods such as replacing the tube with a new one were being used, but due to time and
In addition to being costly and labor-intensive, it has become difficult to implement due to problems such as traffic obstruction and noise.

Therefore, various methods have been devised and implemented to regenerate the inner surface of existing pipes that are leaking while still being installed. These include methods of applying lining material to the inner surface of the pipe and methods of press-fitting lining material into pipe joints, but when implementing these methods, problems arise within the pipe, especially at the bottom of the pipe and Dust and rust are present in the joints, and they harden, impairing the filling of the lining material into the joints, impairing the effectiveness of relining, and the adhesion between the inner walls of the pipe.

Conventionally, surface treatment was performed to remove dust and rust using wire brushes, sand jets, etc., but 1) the cost of surface treatment was high, 2) the pipes were significantly damaged by surface treatment, and ) There were drawbacks such as the inability to completely remove dust and rust that had entered gaps in the joints.

Therefore, before lining the lining material, a low-viscosity undercoat composition that is impregnated against dust and rust is applied in advance so that the lining effect can be achieved without removing such dust and rust. Undercoating is performed to fix dust and rust and form an undercoat film.

The characteristics required of this undercoat composition for surface treatment include permeability that allows it to penetrate into dust and rust layers that cannot be penetrated by lining materials, and the ability to fix these dust and rust layers and create a sealing effect. The undercoat that has been used in the past has not been found, although it exhibits curable curability and crack resistance that does not cause cracks in the cured product due to shrinkage during curing.

Therefore, the present inventors conducted various studies with the aim of obtaining an undercoat composition that satisfies all 11 of these properties and is useful as a base treatment for pipe linings. The present inventors have discovered that an undercoat composition with good penetration into dust and rust layers and excellent curability and crack resistance can be obtained by blending the above with the following.

That is, this invention uses dicyclopentenyl (meth)acrylate and/or dicyclopentenyloxyalkyl (meth)acrylate-1-70 to 90% by weight, glycidyl (meth)acrylate 10 to 20% by weight, and other alkyl (meth)acrylates. A monomer component containing 0 to 20% by weight of acrylate and a total amount of glycidyl (meth)acrylate and other alkyl (meth)acrylates of 10 to 30% by weight, and an effective amount of a catalyst for oxidative hardening of this monomer component. This is a one-of-a-kind undercoat composition for pipe lining.

In this specification, the term (meth)acrylate refers to both acrylate and methacrylate for convenience.

The undercoat composition of the present invention includes synchlopentenyl (meth)acrylate and dicyclopentenyloxyalkyl (
Because meth)acrylate has an autooxidizing functional group, it has excellent curability, and in particular, when curing with a peroxide catalyst, it is not affected by oxygen in the air and curing is not inhibited. The coating film has excellent surface hardening properties.

In addition, since these compounds have a bulky dicyclopentenyl group, the undercoat composition is less prone to curing shrinkage due to the steric hindrance of this group during the curing reaction, so the cured product does not develop cracks and is excellent. Indicates crankability.

Furthermore, since the undercoating composition of the present invention uses monomers with low molecular weight and excellent permeability such as glycidyl (meth)acrylate and other alkyl (meth)acrylates, the above-mentioned dicyclopentenyl group-containing compound is The glycidyl (meth)acrylate used here can compensate for the disadvantage of poor permeability due to its bulky cyclic substituent.Moreover, the glycidyl (meth)acrylate used here Compared to molecular weight (meth)acrylates, it has a lower rate of deterioration in crack resistance, and since it has an epoxy base, it has good compatibility with epoxy resin-based lining materials, which are commonly used as lining materials. Therefore, the undercoat film and the lining material have excellent adhesion.

In the undercoating composition of the present invention, the monomer component 7
0 to 90% by weight, preferably 75 to 85% by weight, is dicyclopentenyl (meth)acrylate and/or dicyclopentenyloxyalkyl (meth)acrylate. If the amount of these compounds used is less than 70% by weight, the curability and crack resistance will be poor, and if it exceeds 90% by weight, the permeability will be poor, which is not preferable. Dicyclopentenyloxyargyl (meth)acrylate in nU is a monomer where acrylate is represented by the formula % formula %, and methacrylate is a monomer represented by the formula 1 H2C=C(CH3)-C-0-R-0℃G. Among these monomers, dicyclopentenyloxyethyl (meth)acrylate is preferred.

Furthermore, in the undercoating composition of the present invention, 10% of the monomer component is
~20! ft% is glycidyl (meth)acrylate. If the amount of this compound used is less than 10% by weight, the permeability will deteriorate, and if it exceeds 20% by weight, the curability and crack resistance will deteriorate, which is not preferable.

Additionally, 0-20% by weight of the monomer component and 7% of other alkyl (meth)acrylates are used.

Specific examples of this compound include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate), 1so-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Which can be mentioned. The amount of this compound used is 20q1゜1j
If it exceeds 1%, curing properties and crack resistance deteriorate, so it is not preferable.

The monomer component contains the above-mentioned compounds in the specific proportions described above, and furthermore, the total amount of glycidyl (meth)acrylate and other alkyl (meth)acrylates in the monomer component is 0 to 30'tJtLJi%, preferably needs to be 15 to 25% by weight. If this proportion is less than 10% by weight, the permeability of the undercoat composition will be poor, and if it exceeds 30JJt, the curability and crack resistance will be poor, which is not preferable.

The undercoat composition for pipe lining of the present invention can be obtained by blending an effective amount of a catalyst for oxidative hardening of the monomer component constituted as described above with the monomer component.

Examples of the catalyst include peroxides such as cumene/.hydroboroxide, methyl ethyl ketone/'-oxide, cyclohexanone peroxide, t-butyl peroxybenzoate, and benzoyl peroxide. In addition to these catalysts, metal salts such as cobalt naphthenate, manganese naphthenate, cobalt chloride, and cuprous chloride are usually used as promoters. The amount of these to be used is usually 0.2 to 30 parts by weight of the catalyst and usually 02 to 10 parts by weight of the promoter per 100 parts by weight of the monomer components.

When the undercoat composition of the present invention configured as described above is applied to piping to be lined, it quickly penetrates into rust and dust, hardens in a few minutes to tens of minutes, and has surface hardening properties. Because of its excellent properties, it does not leave any sag on the surface of the coating film (and does not cause cracks due to curing shrinkage). I can do it.

Examples of this invention will be described below.

Examples 1 to 3 Omahi Comparative Examples 1 to 3 Undercoat compositions for pipe lining having the formulations shown in the table below were prepared. The permeability, surface hardening properties, and crack resistance of these undercoating compositions were examined using the following methods.

Permeability: As shown in FIG.
Drill a hole 2 with a diameter of mrn, and in this hole the particle size is about 100]17
About 45 y of iron powder 3 of n was put therein and vibrated to a filling height of about 70 mnr, and about 2 y of undercoat composition 4 was put thereon.

Next, as shown in Figure 2, from the top of test tube 1,
Air pressure P of Ky/cld was applied for 2 minutes, and the height difference ΔH between the original liquid level 5 and the liquid level 5' after permeation of the composition was calculated, and the permeability was expressed by the size of this ΔH. .

Surface curing properties and crack resistance: Approximately 1.50 me of the undercoat composition was placed in a 300 me polyethylene beaker, left to stand at room temperature, and cured, and evaluated visually and by touch.

A cured product with no uncured layer or stickiness on its surface was rated as having good surface curability (◯), and a cured product with an uncured layer or stickiness was rated as poor (x). In addition, cured products without racks have good crack resistance (○), and those with cracks are poor (×).
).

Further, in Example 1, 1.40 parts of dicyclopentenyloxyethyl methacrylate and 1.40 parts of dicyclopentenyl acrylate were used instead of 80 parts of dicyclopentenyloxyethyl methacrylate. With the undercoat composition, almost the same test results as in Example 1 above were obtained.

As is clear from the above results, the piping lining primer composition of the present invention has excellent permeability, surface hardening properties,
It can be seen that it has crack resistance and is extremely practical.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views for explaining a method for testing the permeability of an undercoat composition for pipe lining. Patent Applicant Nitto Electric Industry Co., Ltd. Figure 1 Figure 2 M

Claims (1)

[Claims] (1) 70-90% by weight of dicyclopentenyl (meth)acrylate and/or dicyclopentenyloxyalkyl (meth)acrylate, 10-20% by weight of glycidyl (meth)acrylate and 0-20% by weight of other alkyl (meth)acrylates %, and the total amount of glycidyl (meth)acrylate and other alkyl (meth)acrylate is 10 to 30% by weight, and an effective amount of a catalyst to oxidize and harden this monomer component. Composition.