JPS59171646A - Temporary rust-prevention treated steel 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 temporarily antirust-treated steel pipe having a hardened coating of an active energy ray-curable composition.

Normally, for example, steel pipes are temporarily coated with a protective coating only during the period before they reach the customer, so as not to deteriorate their quality due to rust formation. For this purpose, mineral oil type rust preventive agents, animal and vegetable oil type rust preventive agents, water-soluble resin type rust preventive agents, etc. are used as coating materials. However, conventionally used rust preventives are not always satisfactory. That is, since mineral oil type rust preventive agents do not harden and dry, the coated surface remains stale and drips during transportation and storage after coating, or when used at a consumer's end, contaminating the working environment. In the case of animal and vegetable oil-based rust inhibitors, they generally harden and dry through oxidative polymerization in the air, so it takes a long time to harden, and the process requires volatilization of the solvent blended to adjust the viscosity of the rust inhibitor. There are problems such as environmental pollution. In the case of water-soluble resin-type rust inhibitors, it takes a considerable amount of time to dry and harden using heat source equipment because water evaporates, and in high-efficiency production lines, they are often bundled and packaged without fully curing. In such cases, the steel pipes are stuck together at the mutual contact points, so when the customer unpacks the pipes, the coating at the contact points may peel off, or the uncured rust preventive may sag. There was a problem in that the rust prevention effect was significantly reduced due to coating unevenness and schizo marks when passing through the roll skid, and the commercial value of the steel pipe was significantly lowered.

In order to solve these problems, a rust preventive coating composition that cures with active energy rays such as ultraviolet rays and electron beams (hereinafter referred to as active energy ray-curable composition) is applied to the surface of the steel pipe. A method of instantly forming a cured film by irradiating the active energy ray has been proposed (for example, Japanese Patent Application Laid-open No. 142742/1982). With this anti-rust treatment method that uses active energy rays, the anti-rust agent applied to the steel pipe hardens and forms a dry film by the time it comes into contact with the conveyor roll, so compared to other anti-rust agents that have been used in the past. and,
Roll scratches and skid marks on the film are significantly improved.

However, various types of oil are used in the manufacturing process for steel pipes (for example, in the case of seamless steel pipes, oils are used to improve efficiency when cutting steel pipes, or when using rollers to straighten steel pipes). (oil is used to prevent seizure), a layer of these oils is formed on the surface of the steel pipe.

Various oils are commercially available, but generally naphthenic or paraffinic mineral oils are emulsified in water with a surfactant.

When an active energy ray-curable composition is coated and cured on a steel pipe with such oil on it, (1) it is difficult to get oil and stains because there is no setting time; Because of this, the stress caused by shrinkage during curing is instantaneously released, causing problems such as repellency and other abnormalities on the painted surface, and insufficient adhesion. To solve this problem, it was necessary to clean the surface of the steel pipe as much as possible before painting.

For this purpose, steam cleaning or alkaline degreasing may be considered, but incorporating this into a continuous line requires a large amount of equipment and wastewater treatment costs. In addition, it is difficult to completely remove oil using a simple method of physically removing oil using a metal brush or the like.

The present inventors have solved these problems, and have made it possible to satisfactorily perform anti-corrosion treatment on steel pipes contaminated with oil without cleaning their surfaces. As a result of intensive research into the development of a composition, it was discovered that the objective could be achieved by using a specific hinyl polymer in a composition that is cured by active energy rays, leading to the completion of the present invention.

The full gist of the present invention is (a) a glass transition temperature of 5° obtained by polymerizing one or more monomers having an ethylenically unsaturated group;
C-hi, 10-50 parts by weight of a vinyl polymer with a solubility parameter of 9 to I1.5 (b) One or more compounds having a polymerizable unsaturated group that causes a reaction with active energy rays 50-90 The present invention relates to a temporarily rust-preventing steel pipe having a hardening degree of 11 parts by weight of an active energy ray-curable composition.

The present invention will be explained in more detail below.

Specific examples of monomers having ethylenically unsaturated groups constituting the vinyl polymer used in the present invention include acrylic acid alkyl esters (methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid n-propyl, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate,
dotecyl acrylate, lauryl acrylate, etc.), alkyl methacrylates (methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, isobutyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate,
n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, stearyl methacrylate, tridecyl methacrylate, etc.), addition reaction products of fatty acids and acrylic acid or methacrylic acid ester monomers having an oxirane structure (for example, stearic acid and glycidyl addition reaction product of methacrylate), addition reaction product of oxirane compound containing C3 or higher alkyl group and acrylic acid or methacrylic acid (for example, those described in Japanese Patent Nos. 583185 and 609322), styrene, α -methylstyrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, p-tmt-butylstyrene,
Hensyl acrylate, ethyl methacrylate, itaconate esters (e.g. dimethyl itaconate, etc.), maleate esters (e.g. dimethyl maleate, etc.), fumarate esters (e.g. dimethyl fumarate, etc.)
, acrylonitrile, methacrylaterile, vinyl acetate, hydroxyedyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxymethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, N-methylolacrylamide, Examples include allyl alcohol.

Furthermore, monomers having carboxyl groups in addition to ethylenically unsaturated groups can also be used, and such monomers having carboxyl groups and ethylenically unsaturated groups include acrylic acid, methacrylic acid, crotonic acid, ethacrotonic acid, Propylacrylic acid, itaconic acid, maleic anhydride,
Examples include fumaric acid.

The desired vinyl polymer can be obtained by polymerizing in a conventional manner using one or more of the above-mentioned monomers.

For example, one or more monomer mixtures are mixed with a known polymerization initiator (e.g., azoisobutyroni!-ril, etc.), and the mixture is dropped into a reaction vessel containing a solvent heated to a temperature that allows polymerization, and the mixture is aged. Polymerization can be carried out by The vinyl polymer thus obtained contains a solvent. According to the present invention, the vinyl polymer is mixed with a compound having a polymerizable unsaturated group that reacts with active energy rays and used as a coating composition. A small amount of 1 to 2% or less causes no problem, but a larger amount causes a decrease in curability.

Therefore, vinyl polymers synthesized by ordinary solution polymerization methods are obtained by distilling off the solvent from the reaction mixture using methods such as vacuum distillation, and then producing compounds with polymerizable unsaturated groups that react with active energy rays (for example, "-"). It is preferable to replace the solvent with the above-mentioned acrylic acid alkyl ester, etc. before use.

The vinyl polymer thus obtained must have a glass transition temperature of 5°C or higher. If the glass transition temperature is less than 5'c, water will easily diffuse into the cured coating film of the coating composition, resulting in a decrease in rust prevention.

When it is a vinyl polymer or copolymer, its glass transition temperature is T, G, Fox: Bull, Δm, Ph
ys, Soc,, 1°No, 3. p, 123 (
(1956) formula: % formula % (Tg: glass transition temperature of copolymer, Wn: weight fraction of n monomer, Tgn: glass transition temperature of homopolymer of n monomer).

Further, the vinyl polymer used in the present invention needs to have a solubility parameter of 9 to 11.5.

If this value is less than 9, the compatibility with a compound having a polymerizable unsaturated group that reacts with active energy rays becomes poor, making it difficult to obtain a uniform coating composition; on the other hand, if this value exceeds 11.5. As a result, the adhesion of the mineral oil to the steel pipe deteriorates, making it impossible to obtain the desired rust prevention effect.

In addition, the solubility parameters in ``2'' are determined by J. Appl.
.

Polym, Sci. 12.2359 (1968
) can be obtained by the method described in .

The number average molecular weight of the vinyl polymer used in the present invention is 3.0
It is desirable that it be in the range of 00 to 30,000. If this value is less than 3,000, the strength of the coating film obtained will be insufficient, and if it exceeds 30,000, the viscosity of the coating composition after blending will be too high, making it difficult to apply with normal methods. .

Steel pipes that have been subjected to temporary anti-corrosion treatment as in the present invention have their G coating removed when they are used by customers. Generally, the following methods are used to remove the skin: (1) removal by combustion, (2) physical removal (eg, Shoso 1 to Plus 1-), and (3) removal using alkaline water/8 liquid.

When removing the film using an alkaline aqueous solution, it is desirable that the vinyl polymer has an acid value within a certain range. In other words, a vinyl polymer obtained by copolymerizing a monomer having a carboxyl group and an ethylenically unsaturated group as described above in an amount such that the acid value of the resulting resin solid content is 30 to 120. It is desirable to use it.

Examples of the compound having a polymerizable unsaturated group that causes a reaction with active energy rays used in the present invention include the following compounds having two or more polymerizable unsaturated groups per molecule (hereinafter referred to as "polymerizable"). (referred to as functional compounds).

(a) Polybasic acids or their anhydrides (e.g. succinic acid,
adipic acid, or-1-phthalic acid, tetra-1-1-phthalic acid, hexahydrophthalic acid) and an excess equivalent of a polyhydric alcohol (e.g., ethylene glycol, propylene glycol, 2 moles or more of acrylic acid or methacrylic acid or an acrylic acid or methacrylic acid derivative having a carboxyl group (e.g. 1 mole of succinic anhydride) is added to 1 mole of a polynisyl compound having a human'roxyl group obtained by reacting with erythritol). A polyester acrylate or methacrylate obtained by reacting a reaction product of 1 mole of 2-hydroxyethyl acrylate with phthalic anhydride [a reaction product of 11 moles of 2-hydroxyethyl acrylate and 1 mole of 2-hydroxyethyl acrylate].

(b) Acrylic acid having 2 moles or more of monohydroxyl groups per mole of a polyester compound having carboxyl groups obtained by reacting the above polyhydric alcohol with an excess equivalent of the polybasic acid or anhydride thereof. Alternatively, a methacrylic acid derivative (e.g., 2-hydroxyethyl methacrylate + -12-hydroxyethyl methacrylate-1=) is reacted, or an acrylic acid or methacrylic acid derivative having an epoxy group (e.g., nigericidyl acrylate, glycidyl ivy) is reacted. polyester acrylate or methacrylate obtained by reacting acrylate).

(C) A compound having a hydroxyl group (e.g. ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, trimethylolpropane, the polyester compound having a hydroxyl group described in (a) above) and an excess equivalent of a polyvalent isocyanate compound. (Example: nitrilene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, trimethylolpropane 1
reaction product of mol and 3 mol of tolylene diisocyanate)
A polyurethane acrylate or methacrylate obtained by subjecting the residual isocyanate group to an addition reaction of at least two molecules of the above monohydroxyl group-containing acrylic acid or methacrylic acid derivative.

(d) Epoxy acrylate obtained by addition reaction of two or more molecules of acrylic acid or methacrylic acid or the above-mentioned acrylic acid or methacrylic acid derivative having a carboxyl group and an epoxy compound (e.g. condensation product of epichlorohydrin and hisphenol A). or methacrylate-1.
.

(e) L6 hexanethiol cyacrylate 1 note, neopentyl glycol diacrylate, 1,10-decanediol diacrylate, trimethylolpropane triacrylate acrylate, dipentaerythritol hexaacrylate, 1,6-hexanethiol dimethacrylate, Neopentyl glycol diacrylate 110-decanediol dimethacrylate-1-, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexamethacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate-1, utylene glycol dimethacrylate i-, diethylene glycol dimethacrylate,
Dipropylene glycol diacrylate, dipropylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate-1-, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, Polypropylene glycol diacrylate, polypropylene glycol dimethacrylate.

In the present invention, one or two such polyfunctional compounds are used.
It is preferable to use more than one species. In addition, a polymerizable unsaturated group that causes a reaction with active energy rays is included in the molecule l (l
A monofunctional compound having id can be used in combination with the above polyfunctional compound, or only the monofunctional compound can be used.

When alkaline film removability is required, a polyfunctional compound having a carboxyl group (for example, a compound obtained by adding an acid anhydride such as phthalic anhydride to the epoxy acrylate mentioned in section (d) above) or a compound having a carboxyl group A monofunctional compound (for example, a compound obtained by adding an acid anhydride such as terahydrophthalic anhydride to 2-hydroxyethyl acrylate) may be blended.

In the temporarily rust-prevention treated steel pipe according to the present invention, vinyl polymer 10
The desired purpose can be achieved by forming a film of a coating composition containing 60 to 90 parts by weight of a compound having a polymerizable unsaturated group that reacts with active energy rays to 50 parts by weight, but vinyl If the amount of the polymer is less than 10 parts by weight, the adhesion on the steel pipe surface coated with mineral oil will decrease;
If the amount exceeds 0 parts by weight, the viscosity of the coating composition after blending becomes too high, making it difficult to coat using the Tsutomi coating method.

In the coating composition used in the present invention, in addition to the essential components listed above, photosensitizers, pigments, additives, etc. may be added as necessary. A photosensitizer is used when ultraviolet rays are used as active energy rays. As a specific example,
Examples include benzoin, benzoin methyl ether, hengein ethyl ether, henzoin isopropyl ether, henziin isobutyl ether, hensyl, hensifhenone, 2,2'-die-1-quinacetophenone, 2-methylanthraquinone, and 2-ethylanthraquinone. One or more types of such sensitizers can be used, and the amount added is 0.1 to 10% (by weight, hereinafter the same) based on the compound having a polymerizable unsaturated group in the coating composition. ) is preferable.

The coating composition used in the present invention having such a configuration may be applied to a steel pipe, and then immediately irradiated with active energy rays to be cured. As for the application method, in addition to the usual methods such as brushing, spraying, etc.
The coating method disclosed in No. 31336 can also be adopted. As sources of active energy rays, ultraviolet ray generators such as isopressure mercury lamps, ultra-high pressure mercury lamps, and metal halide lamps, electron beam accelerators, and T-ray sources such as cobalt-60 can be used.

Next, the invention will be specifically explained with reference to synthesis examples and examples.

380 g of luene was placed in a 11 separable kolben equipped with a reflux condenser, dropping funnel, thermometer, and stirring blade, and the temperature was raised to 110°C. A mixed solution of 120 g of ethyl acid, 280 g of methyl methacrylate, and 8 g of ``barbutyl 0'' (trade name, organic peroxide, NOF type) was added dropwise at a constant rate over 3 hours. After stirring for 30 minutes, toluene was added. A mixed solution consisting of 20 g and 2.8 g of "perbutyl O" was added dropwise at a constant rate over 30 minutes, and stirring was continued for an additional hour.Then, the reaction mixture was heated, and 1 to toluene was distilled off at normal pressure.
After the content temperature reached 130° C., toluene was further distilled off at the same temperature for 30 minutes, and 300 g of toluene was recovered. After cooling the contents to 90°C, 0.51g of hydroquinone
, add 205° 4g of carchtol acrylate,
Toluene was distilled off under reduced pressure at 0°C, 13 mm, and 11 g for 30 minutes, and an additional 80 g of toluene was recovered. The concentration of vinyl polymer in the obtained resin composition was 64.5%.

nnff1LLIJjLL A resin composition containing a vinyl polymer was synthesized in the same manner as in Synthesis Example 1, except that the monomers and polymerization initiators shown in Table 1 were used. Table 1 also shows the characteristic values of each of the vinyl polymers obtained.

A coating composition was obtained by stirring and mixing the components at room temperature according to the formulations shown in the following formulation examples using a resin composition containing the hinyl polymer obtained in each Synthesis Example.

On the other hand, a black-skinned iron plate (J
IS G 3]41) was immersed and then taken out and left indoors for about 10 minutes to prepare a black iron plate to which mineral oil was evenly adhered. Each of the above-mentioned coating compositions was applied onto the black iron plate using a bar coater #18, and immediately applied from the lower end of a 2K, W high-pressure mercury lamp (using a condensing type lamp, 80W/cm type lamp, Japanese battery layer). Ultraviolet rays are irradiated by passing through a position of 13 cm at a speed of 6 m/min perpendicular to the length direction of the lamp.
The coating was cured.

The obtained coated iron plate was visually inspected for any abnormality in appearance, and further adhesion and corrosion resistance were measured. The result is the second
Shown in the table.

Formulation - Example - Resin composition obtained in each synthesis example 40 parts: 1 part
- 20 parts of trimethylolpropane triacrylate epichlorohydrin and bisphenol A 16 Mtt
Epoxy acrylate made by adding 2 moles of acrylic acid to 1 mole of polycondensation product of M (trade name: Lipoxy VR-80) Carpitol acrylate 20 parts by weight! Zoin Ie γoe, Ruether--1 layer 1 piece 10
0 parts by weight "Chintochi" column ↓ Coating compositions include I, 1,000 roll propane I, 1-20 parts by weight of Reacrylic, 1-20 parts by weight of Lipoxy VR-8015, 1.15 parts by weight of Carbitol acrylate, and Henge. A black iron plate having a cured film of this composition was prepared using a composition consisting of 2.5% in isopropyl ether and subjected to a test in the same manner as in Example 1.

The results are also shown in Table 2.

Table 2: Appearance: Evaluate in 3 grades: ◯, △, and ×, depending on the degree of occurrence of abnormalities in the appearance of the coating film, such as cracks, dents, etc.

Adhesion: Make 1.00 1mm wide goblets on the coating film,
After peeling off the adhesive tape adhered to this, depending on the number of coatings remaining on the iron plate, ○ (more than 80% remaining), △ (50 to 79%)
Evaluation is made in three stages: (Remaining), X (Less than 50% remaining).

Corrosion resistance: Salt spray test (JIS Z 2371) 72
It is expressed as the percentage of rust formation after hours.

(Note 1) The compound causes layer separation into the resin layer and other component layers,
Since a homogeneous solution could not be obtained, it was not used for testing.

Examples Using the coating composition according to the formulation of Example 1 using each resin composition of Synthesis Examples 1 and 2, and the coating composition of Reference Example 1, a mineral oil-based lubricant coolant "Daicool 01, = 26" was prepared.
°゛ (manufactured by Daido Kagaku Kogyo KK) was applied to a steel pipe (diameter 57mm, wall thickness 3n+m) that had been treated with slate toner, and immediately a 2KW high-pressure mercury lamp (using a condensing lamp),
Irradiation was uniformly performed for 1.5 seconds from the surrounding area using an o-/cm type lamp (Japanese Battery Layer) at a distance of 8 cm from the surface of the steel pipe. Table 3 shows the appearance of the obtained coating and the results of the performance test.

Table 3 ■ In Table 3, the evaluation criteria for appearance, adhesion and corrosion resistance are the same as in Table 2.

Although the invention has been described above with respect to steel pipes, it will be understood that the invention is also applicable to bars.

Applicant: Sumitomo Metal Industries, Ltd. Agent: Patent Attorney Akira Hirose -

Claims (2)

[Claims] (1) (a) One or two types having an ethylenically unsaturated group
10 to 50 parts by weight of a vinyl polymer having a glass transition temperature of 5°C or higher and a solubility parameter of 9 to 11.5, obtained by polymerizing more than one type of monomer, and (b) polymerizable, which causes a reaction with active energy rays. One or more compounds having an unsaturated group 50 to 90
A temporarily rust-preventing treated steel pipe having hardening resistance of an active energy ray-curable composition consisting of parts by weight. (2) The above hinyl polymer is obtained by copolymerizing a monomer having a carboxyl group and an ethylenically unsaturated group in an amount such that the acid value of the resin solid content is 30 to 120. A temporarily rust-proofed steel pipe according to claim 1.