JPS58209556A - Polyolefin painted body - 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 coated body using polyolefin as a coating material.

Conventionally, for example, the surface of metal products has been coated with polyolefin for the purpose of preservation, corrosion prevention, etc., but at this time, it is necessary to ensure sufficient adhesion strength between the polyolefin coating film such as polyethylene coating and the object to be coated. In order to do so, it is necessary to use primers. For example, it is known to use a mixture of epoxy cretane resin, epoxy resin, and curing agent as a primer, or to use an aqueous solution of an organic polymer such as polyacrylic acid or polyvinyl alcohol as a primer, but in the case of a curved epoxy primer, The adhesion with non-polar polyethylene coatings is insufficient, and the latter also has similar problems, so when painting polyolefins, polyethylene etc.
A method of forcibly applying oxidation coating at a high temperature of 80 degrees Celsius is used, but in this case, the quality of the tap water flowing through the pipes deteriorates due to oxidation deterioration of polyethylene, etc. There is a tendency to
Furthermore, since the primer is hydrophilic, there is a problem with long-term water resistance.

In view of the above-mentioned current situation, the present invention has been made for the purpose of providing a coated body coated with a polyolefin that has excellent adhesion of the coating film and also has excellent water resistance. 'i1 A paint made of polyolefin is coated on one primer coated with a mixture of a diene polymer or a hydrogenated compound having two or more carboxyl groups in the force and a polyfunctional epoxy compound. It consists of a polyolefin coated body.

In the present invention, a diene polymer having two or more VC carboxyl groups in one molecule or a hydrogenated product thereof is used.
It can be obtained by reacting a diene polymer having 1 or more hydroxyl groups or its hydrogenated product with a polyhydric carboxylic acid such as maleic acid, 7-maric acid, iconic acid, phthalic acid, or its acid anhydride. However, in addition to this method, 1,
3-butadiene, isoprene, 1°3-pentadiene,
2. Combine conjugated diene monomers such as 3-dimethylgetadiene and chloroprene! It can also be obtained by polymerizing a dithiodicarboxylic acid such as dithiodicarboxylic acid as a transfer agent and introducing a carboxyl group at the end of the polymer. And the molecular weight of the carboxyl group-containing diene polymer is #-1so.

It is preferable that it is about 5,000 to 5,000.

The diene polymer having two or more hydroxyl groups at the terminal VC can be obtained by forming a conjugated diene as described above alone or by mixing it with a vinyl thread thread such as styrene, acrylic thread thread, or vinyl pyridine. It can be easily obtained, and mainly 1,4-polydiene type products are obtained by this method. In addition, in the above case, when a vinyl yarn yarn is mixed, it is usually preferable to mix the vinyl yarn yarn with an f'i of 50% or less of the mixed yarn, more preferably 20% or less. In addition, by reacting a diene-based living polymer with an epoxy compound such as halogenoalkylene oxide,
The above hydroxyl group-terminated diene polymer can also be obtained by the following method of treatment with protonic acid, and by this method, t-4
Mainly 1,2-polydiene type products are obtained.

Moreover, hydrogen t#m product Fi of the above hydroxyl group-terminated diene polymer
It can be obtained by hydrogenating the diene polymer using a hydrogenation catalyst such as a nickel, Ewald or rhodium catalyst.

For a long time, the polyfunctional epoxy compound used in the present invention refers to a compound containing two or more epoxy groups tP in the molecule, and is usually 2,2-bis(4'-oxydiphenyl)furonohin. (abbreviated as bis7-el/-A) is used, and the reaction product shown by the following general formula is used, and n in the formula is 1 to 12.
are preferably used.

In addition, the above-mentioned bisphenol AK, which uses an initial combination of phenol and formaldehyde, is also preferably used.

In the present invention, a primer containing a mixture of the carboxyl group-containing diene polymer and the polyfunctional epoxy compound is applied to an object to be coated such as a metal molded object.
However, the mixture of the above diene polymer and a polyfunctional epoxy compound! For lJ &, it is preferable to add them together so that the molar ratio of carboxyl group to epoxy group is in the range of α8 to L2, and more preferably, to add them together so that the molar ratio is 1=1. It is better.

Further, the thickness of the primer field is preferably 50μ or less, but since the thinner the coating tends to be, the adhesion strength of the coated body improves, it is more preferable to use a coating thickness of 20P or less: V/L .

In addition, fillers such as carbon blank, calcium chloride, titanium dioxide, clay, silica, coloring agents, antioxidants, ultraviolet absorbers, etc. can be seen in the above primer depending on the μ requirement. Alternatively, if the object to be coated is a metal product such as iron, it is also possible to obtain a rust preventive effect by adding rust preventive materials such as metal powder such as zinc or metal agglomerates such as red red iron. It is.

However, the pot life of the primer used in the present invention is usually 10 days or more at room temperature, which is significantly longer than the bond life of about 2 days for conventional flexible primers. It is simple and has excellent workability.

To apply a primer to an object to be painted, a solution of the primer dissolved in an appropriate solvent such as xylene is sprayed with a spray gun or the like and dried, but a fine powder of the primer is applied using a powder coating method. The above method can be adopted, but it is usually best to heat the coating to about 180°C or higher after painting.
The heating causes the functional groups of the resin components in the primer to warp and crosslink, forming a single layer of primer with excellent heat resistance and water resistance.

The coated body of the present invention is obtained by coating a single layer of the primer with a paint made of polyolefin such as polyethylene, and an appropriate coating method such as a powder coating method may be employed for this coating.

The polyolefin coated body of the present invention has the structure as described above, and is coated with a mixture of a diene polymer having two or more VC11 carboxyl groups in one VC molecule, or a hydrogenated product thereof, and a polyfunctional epoxy compound. The primer layer is formed between the object to be coated and the polyolefin coating film, and the adhesion strength between the primer layer and the object to be coated, such as a metal product, and the bonding strength between the primer layer and the polyolefin coating film. The adhesion strength of the paint film to the object to be coated is also excellent due to the excellent adhesion strength of both, and at the same time, the water resistance and heat resistance of the paint film are also excellent.

The present invention will be explained below based on examples.

Example 1 Hydroxy polybutadiene with a number average molecular weight of 2800 and a hydroxyl value of 47 was dissolved in 600 rk dehydrated toluene and mixed with 50 y maleic anhydride and 100 rk in an argon stream.
The reaction was carried out at 5 o'clock C. After completion of the reaction, toluene was distilled off to obtain polygetadiene 650y having a carboxyl group at the end of ll4fIi43 qKoIi/y.

Next, so many steel pipes with a nominal diameter of 151111% and a length of s! i! fJr, prepare a steel pipe that has been completely descaled and subjected to zinc phosphate treatment (t2P/d), and coat the inner surface of the steel pipe with 10gJ of polybutadiene and bisphenol-type epoxy (terminated with carboxyl groups obtained above). Product name Epicote 828.

A primer prepared by dissolving 13.69 k# syrene 200y in epoxy resin was applied with a spray gun and dried at 250'C for 5 minutes. The average film thickness of the primer at this time was Fi10/A.

Seven bales This steel pipe was preheated to 250"CK in pure air, and a mixed fluid of polyethylene powder and air was passed through the inner surface of the steel pipe to melt 1g for about 10 minutes.
1li was adhered to form a polyethylene coating with a thickness of 900 to 1000 μm on the inner wall surface of the tube.

The adhesion of this steel pipe coating at 25°C is 18 in 10 frost.
The figure on the left shows 9.0 lines/a using the 0 peel method. In addition, the above polyethylene coated steel pipe was cut to an appropriate length and placed in muddy water at 50°C [2
After immersion for 10 days, the adhesion was measured using the same method as above, and the adhesion was almost the same as before immersion, and no peeling of the coating from the end surface of the steel pipe was observed.

Example 2 Hydride of hydroxypolybutadiene obtained by adding hydrogen to hydroxypolybutadiene with a number average molecular weight of 2800 and a hydroxyl value of 47 (iodine value α5) 300
p was reacted with maleic anhydride in the same manner as in Example 1 to obtain terminal half-esterified hydrogenated polybutadiene having an acid value of 43. A primer obtained by dissolving this polymer 100y and bisphenol type epoxy (part name Epicor) 828) 14yt-xylene 2009VC was applied to the pickled steel plate surface and dried at 180°C for 10 minutes. The average film thickness of one primer was 50 μm. Next, this steel plate was preheated to 250'CK on a hot plate, and powder coated with the same polyethylene as in Example 1 to a film thickness of 900°C.
A film of ~1000μ was formed. Adhesion strength Fi10 of this steel plate film. IL OKF / by 1800 peeling method
It was txs. Furthermore, the adhesion after 210 days of immersion in 5oC warm water was almost the same as before immersion, and no peeling of the film was observed from the incisions made during immersion.

Comparative Example I Bisphenol type epoxy (trade name Epicote 828) 100! KV Example 2 on a steel plate using a primer consisting of 30y of phthalic anhydride and
Primer coating (average film thickness 50P) and polyethylene powder coating (film thickness 900-1000μ) were performed in the same manner as in Example 2, and the adhesion was measured in the same manner as in Example 2. The adhesion was α5~L〇-edge/ It was es.

Comparative Example 2 A steel pipe with a nominal diameter of 15% was pickled, treated with zinc phosphate, and ethylene-vinyl acetate copolymer powder was adhered to the inner surface of the steel pipe, followed by heat melt bonding and a single layer of primer with a film thickness of 150μ. Formed.

Next, in the same manner as in Example 1, a film thickness of 900 to 1 was applied to the inner surface of the steel pipe.
6. Adhesion strength: A polyethylene film of 000μ was formed and the adhesion strength was measured in the same manner as in Example 1. θ time/1. Also, adhesion force f′i2 after immersion in warm water [210 days]
txr or less, the coating had peeled off over 30% of the end of the steel pipe, and Vcri rust had occurred in that area.

patent applicant Sekisui Chemical Co., Ltd. Representative: Mototoshi Fujinuma

Claims (1)

[Claims] 11 A paint made of polyolefin is coated on a primer strip coated with a mixture of a diene polymer having two or more carboxyl groups in the molecule or its hydrogenated product and a polyfunctional epoxy compound. polyolefin coated body,