JPH04106174A - Primer composition for preventing corrosion - Google Patents

Abstract

PURPOSE:To obtain the title composition improved in adhesion between a metal surface and an adhesive layer comprising a rubbery polymer and in anticorrosiveness by dissolving a rubbery polymer and a specified coupling agent in a solvent. CONSTITUTION:5-30wt.% rubbery polymer preferably comprising an olefin rubber and 0.5-20wt.% silane coupling agent having at least one mercapto, vinyl or methacryloxy group in the molecule, or chelate titanate coupling agent are dissolved in a solvent preferably comprising a lower aliphatic hydrocarbon or aromatic hydrocarbon. If necessary, a tackifier, a filler, a softening agent, an age resister, etc., are added to the solution.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a corrosion-proofing primer composition used for corrosion-proofing construction of metal products.

<Prior Art> Pipelines used for transporting fluids such as oil, gas, water, etc. are often buried underground, and countermeasures against corrosion are important.

In addition to cathodic protection methods, known corrosion protection methods for such transport structures include providing coatings made of high-polymer materials with excellent electrical insulation properties on metal surfaces to block external air. Anticorrosion tape is often used. Anticorrosive tape is made of polyolefin support such as polyethylene resin, ethylene-vinyl acetate copolymer resin, ethylene-propylene copolymer resin, ethylene-ethyl acrylate copolymer resin, or polyvinyl chloride support, and is made of butyl rubber, ethylene, etc. propylene terpolymer,
Mainly made of rubbery polymers such as polyisobutylene rubber,
The adhesive layer coated with a tackifier, filler, softener, anti-aging agent, etc. is used. Such anti-corrosion tape is a primer-activated type, and when installed, the adhesive layer of the tape is made compatible with the primer and adhered to the metal surface. Properties required of such anticorrosive tapes include moisture resistance, water resistance, and hot water resistance.

<Problems to be Solved by the Invention> However, high-temperature crude oil, gas, steam, hot water, etc. are usually transported in pipelines, and the pipes themselves become highly heated due to these high-temperature fluids.

In addition, pipelines are often buried underground or in humid areas, and the heat and moisture of the steam can destroy the adhesion between the anticorrosive tape and the metal surface. At present, it is difficult to use the above-mentioned anticorrosion tape in a high temperature and high humidity environment.

<Means for Solving the Problems> As a result of intensive studies to solve the above problems, the present inventors have developed a primer composition used for adhesion between an adhesive layer mainly composed of a rubbery polymer and a metal surface. The present invention was completed based on the knowledge that a combination of a rubbery polymer, a specific force, and a Punong agent is suitable as a product.

That is, the gist of the present invention is to provide a primer composition used for adhesion between an adhesive layer made of a rubbery polymer and a metal surface, the primer composition comprising a rubbery polymer and at least one mercapto in the molecule. a silane coupling agent or a chelate titanate camping agent having a group, a vinyl group, or a methacryloxy group as an essential component, and the rubbery polymer is 5 to 30% by weight in 100% by weight of the solution. agent is 0.5~
The content is in the range of 20% by weight.

<Action of the invention> In the case of a silane-based coupling agent, the hydrolyzable group of the coupling agent generates a silanol group by the action of a trace amount of water contained in the adhesive layer of the anticorrosion tape, and combines with the hydroxyl group in the oxide film formed on the metal surface. In the case of titanates, they either directly cause a condensation reaction with hydroxyl groups or act directly on the metal surface of the adherend through hydrogen bonding, and both exhibit high adhesion. On the other hand, since the mercapto group, vinyl group, methacryloxy group, and phosphoric acid type hydrophobic group present in the molecule of the coupling agent react or bond with the polymer component in the adhesive layer, this coupling agent acts as a bridge. This can improve the adhesion between the metal surface and the adhesive layer. Also,
Rubbery polymers are compatible with the rubbery polymers used in the adhesive layer of anticorrosion tapes, but especially when olefin rubber is used, they become compatible and integrated with the adhesive layer of anticorrosion tapes, resulting in moisture resistance, It is preferable because it has excellent water resistance.

<Structure of the Invention> The silane coupling agent constituting the anticorrosion primer composition of the present invention is not particularly limited as long as it has at least one mercapto group, vinyl group, or methacryloxy group in the molecule, but for example, , 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, etc. Chelate titanate coupling agents include bis(dioctyl (pyrophosphate) oxyacetate titanate, bis(dioctylpyrophosphate) ethylene thicate, etc., and they can be used alone or in combination.

In the above, in the case of a mercapto group, the SH residue reacts with the rubbery polymer in the brimer and adhesive layer described later by a vulcanization reaction, and in the case of a vinyl group or methacryloxy group, a polymerizable double bond residue Hz
"" CHCHz =C(CH,) forms a chemical bond with the rubber through a graft reaction using the active radical slightly present on the rubbery polymer of the adhesive as a base point. In addition, in the case of a coupling agent having a vinyl group or methacryloxy group, the above-mentioned graft reaction can be further promoted by adding a peroxidizing substance to the primer or adhesive layer. On the other hand, in the case of phosphoric acid-type hydrophobic groups, although the mode of action on rubber is not clear, it is presumed that an interaction occurs due to compatibility between the phosphoric acid-type hydrophobic groups and hydrophobic domains in the rubbery polymer. Ru.

The rubbery polymer used in this invention includes sulfur vulcanized,
Those capable of crosslinking reactions such as peroxide crosslinking are preferred, and are selected from, for example, butyl rubber, ethylene propylene terpolymer, polyisobutylene rubber, etc., and these can be used alone or in combination.

Among these, olefin rubbers such as butyl rubber and ethylene propylene terpolymer are preferred.

Therefore, when butyl rubber is used as the rubbery polymer, among the coupling agents mentioned above, a silane-based camping agent or a chelate titanate-based camping agent having a mercapto group is used, and when an ethylene propylene polymer is used, the above-mentioned coupling agent is used. Among the ring agents, a silane coupling agent or a chelate titanate coupling agent having a vinyl group or methacryloxy group is selected, and when using polyisobutylene rubber, a chelate titanate coupling agent is selected from among the above camping agents. This is preferable.

A brimer composition is prepared by mixing and dissolving these rubbery polymers and the above-mentioned camping agent. Preferred are low aliphatic hydrocarbons such as hexane and pentane, and aromatic hydrocarbons such as toluene. Furthermore, tackifiers, fillers, softeners, anti-aging agents, etc. may be added to these primer compositions as necessary.

Therefore, in the present invention, it is important that the rubbery polymer is contained in the range of 5 to 30% by weight and the aforementioned camping agent is contained in the range of 0.5 to 20% by weight in 100% by weight of the solution. Preferably, the rubbery polymer is 10 to 20% by weight.
, the amount of the above-mentioned coupling agent is preferably in the range of 1 to 5% by weight. If the rubbery polymer is less than 5% by weight in 100% by weight of the solution, the effect of compatibility and integration between the rubbery polymers in the brimer and the adhesive layer will be weak, and if it exceeds 30% by weight, the viscosity will increase and become uniform. It becomes difficult to apply to the surface.

Furthermore, if the amount of the coupling agent is less than 0.5% by weight, it is difficult to obtain the effect of the coupling agent;
If it exceeds 0% by weight, a large amount of unreacted coupling agent will exist near the adhesive interface, which is undesirable.

The anticorrosion tape to which the primer composition according to the present invention is applied includes polyethylene resin, ethylene-vinyl acetate copolymer resin, ethylene-propylene copolymer resin,
A rubbery polymer based on olefin rubber such as butyl rubber, ethylene propylene polymer, or polyisobutylene rubber is applied to a polyolefin support such as ethylene-ethyl acrylate copolymer resin or polyvinyl chloride resin. Imparting agents, fillers,
Those coated with an adhesive layer containing softeners, anti-aging agents, etc. are mainly used.

When winding an anticorrosion tape using the primer composition of the present invention, first apply the primer composition to a metal surface such as a steel pipe to a thickness of 10 to 3 mm after drying.
The usual method is to apply the anti-corrosion tape to a thickness of about 0 μm and wrap the anti-corrosion tape in layers before the solvent evaporates. Coating methods such as dipping, spraying, and brushing can be used to apply this primer composition. The anticorrosion coating layer obtained in this way has excellent adhesion, especially moisture resistant adhesion, water resistant adhesion, and hot water resistant adhesion due to the action of the camping agent, and therefore has a good anticorrosion effect. It is something.

<Example> Next, the present invention will be specifically explained using examples.

"Middle part" means part by weight (% by weight).

Example 1 10 parts of butyl rubber (Butyl #26B, manufactured by Ko-So ■), 1 part of petroleum resin (Escolettes 1202, manufactured by Enso ■)
After kneading 3 parts of Asahi Carbon (manufactured by Asahi Carbon ■) using a mixing roll, 76 parts of toluene and 1 part of 3-mercaptopropyltrimethoxysilane were added and dissolved to obtain a primer composition. An iron plate (40x1.50m+n, 2f thick) sandblasted with this primer composition.
fIln) so that the thickness after drying was 20 μm, and 10 seconds later, a piece of anticorrosive tape was attached. The anti-corrosion tape piece is 300μm thick and cut into 20x150m pieces.
100 parts of butyl rubber and 50 parts of ethylene propylene polymer as an adhesive layer on a polyethylene tape support of
An adhesive consisting of 70 parts of heavy calcium carbonate, 10 parts of carbon, 40 parts of petroleum resin, and 10 parts of process oil was applied to a thickness of 0°4.

The test piece thus prepared was aged in a dryer at 80°C for 10 days to form an adhesive, and then immersed in hot water at 95°C for 500 hours and 1000 hours.
The 0° pilling adhesive strength was measured and compared with the initial value (adhesion strength before dipping).

Example 2 The same procedure as Example 1 was carried out except that butyl rubber was changed to 20 parts and toluene was changed to 66 parts.

Example 3 The same procedure as Example 1 was carried out except that 3-mercaptopropyltrimethoxysilane was changed to 5 parts and toluene was changed to 72 parts.

Example 4 The same procedure as Example 1 was carried out except that vinyltrimethoxysilane was used as the silane coupling agent.

Example 5 The procedure was the same as in Example 1 except that 3-methacryloxypropyltrimethoxysilane was used as the silane cambling agent.

Example 6 Except for using bis(dioctylpyrophosphate)oxyacetate titanate as a coupling agent,
The procedure was the same as in Example 1.

Comparative Example 1 The primer composition was the same as Example 1 except that no coupling agent was added and toluene was 77 parts.

Comparative Example 2 The same procedure as Example 1 was carried out except that 3-mercaptopropyltrimethoxysilane was changed to 0.4 parts and toluene was changed to 76.6 parts.

Comparative Example 3 The same procedure as Example 1 was carried out except that 3-mercaptopropyltrimethoxysilane was changed to 30 parts and toluene was changed to 47 parts.

Comparative Example 4 The same procedure as Example 1 was carried out except that butyl rubber was not added to the brimer composition and toluene was 86 parts.

Comparative Example 5 The same procedure as Example 1 was carried out except that butyl rubber was used as 1 part and toluene was used as 85 parts.

Comparative Example 6 The same procedure as Example 1 was carried out except that 3-glycidoxypropyltrimethoxysilane was used as the silane coupling agent.

Table 1 shows the measurement results of the initial value, 180° peeling adhesive strength after immersion for 500 hours, and after immersion for 1000 hours in the above Examples and Comparative Examples.

Table 1 180° pilling adhesive strength is 20mm/23°C at 23°C.
The results are shown in kg/Cm, which was performed at a peeling speed of +in.

As shown in Table 1, in the comparative example, the adhesive strength after immersion in hot water was extremely reduced, and moisture generally penetrated between the adhesive layer of the tape and the iron plate surface, whereas in the example example The adhesive exhibited sufficient adhesion even after immersion in hot water.

<Effects of the Invention> Since the present invention is as described above, by applying this to the metal surface and applying the anticorrosion tape during anticorrosion construction, steel pipes and the like in which high temperature fluids are transported can be kept in good condition for a long period of time. It is possible to form an anti-corrosion layer that exhibits excellent anti-corrosion effects. Therefore, it is now possible to carry out anti-corrosion work using conventional anti-corrosion tape even in high temperature and high humidity environments.

Claims (2)

[Claims] (1) A primer composition used for adhesion between an adhesive layer mainly composed of a rubbery polymer and a metal surface, which contains a rubbery polymer and at least one mercapto group, vinyl group, or methacryloxy group in the molecule. The solution contains a silane coupling agent or a chelate titanate coupling agent as an essential component, and the rubbery polymer is 5 to 30% by weight in 100% of the solution, and the coupling agent is 0.5 to 20% by weight. An anticorrosive primer composition characterized in that the content of the primer composition is within a range of %. (2) The anticorrosive primer composition according to claim 1, wherein the rubbery polymer in the primer composition is mainly composed of olefin rubber.