JPS6335665A - Paint composition for iron pipe - Google Patents

Abstract

PURPOSE:To obtain a paint for iron pipes, which contains no carcinogen and gives a coating film which hardly causes discoloration and cracking, by blending a specified epoxy resin with a curing agent, gilsonite, a petroleum resin and a chlorinated polyethylene. CONSTITUTION:A paint compsn. contains a film-forming component consisting of 100pts.wt. epoxy resin having at least two epoxy groups per molecule and an epoxy equivalent of 150-1,000 and curing agent therefor (a), 50-200pts.wt. gilsonite (b), 20-180pts.wt. petroleum resin (c) having a number-average MW of 2,000 or below and 10-50pts.wt. chlorinated polyethylene (d). Gilsonite is used to improve chiefly rust proofness. As the petroleum resin, low-molecular polymers having an average MW of 500-2,000 are used. When the MW is higher than the above upper limit, the flexibility of the coating film is lowered. The chlorinated polyethylene has an effect of improving the impact resistance and the flexural properties of the coating film.

Description

[Detailed Description of the Invention] <Industrial Field of Application> The present invention relates to a coating composition for iron pipes, which is free from carcinogenic substances and provides a coating film that is resistant to discoloration, cracking, etc. .

<Conventional technology> Conventionally, it has been used as a paint for iron pipes such as water iron pipes and gas iron pipes.
Epoxy resin-based paints have been widely used in this type of technical field because they are excellent in rust prevention, water resistance, chemical resistance, etc., and are inexpensive.

<Problems to be solved by the invention> However, tar, that is, coal tar pitch, contains a polyhex component, which contains carcinogenic substances. There has been a desire to develop a paint to replace resin-based paints. However, since there was no alternative paint that was inexpensive and had excellent film performance, we had no choice but to use tar-epoxy resin paint, even though we knew that it had the drawbacks mentioned above. was the actual situation. In addition, cool epoxy resin paints can be used in summer during the drying process of the paint film,
When exposed to strong ultraviolet rays, they often turn brown or crack, and it is necessary to repaint them with an alkyd resin paint or the like before shipping to maintain their aesthetic appearance.

In view of the current situation, the inventors of the present invention have conducted intensive research to find a product that does not contain carcinogenic substances, is inexpensive, is resistant to discoloration, cracks, etc., and has excellent rust prevention, water resistance, chemical resistance, etc. They discovered a coating composition for iron pipes that can provide a coating film equivalent to that of a cool epoxy resin coating, and completed the present invention.

Means for Solving the Problems> That is, the present invention provides: (1) an epoxy resin having an epoxy equivalent of 150 to 1000 and an epoxy curing agent having at least two or more epoxy groups in one molecule and an epoxy curing agent 100 parts by weight (II) Gilsonite Contains a film-forming component consisting of 50 to 200 parts by weight (iii) 20 to 180 parts by weight of a petroleum resin with a number average molecular weight of 2000 or less and 10 to 50 parts by weight of 0φ chlorinated polyethylene, and if necessary, an extender pigment,
The present invention relates to a coating composition for iron pipes, which is dissolved in a suitable organic solvent and contains mineral fillers such as antirust pigments and colored pigments, and various additives.

In the present invention, as the epoxy resin, epoxy resins conventionally used in cool epoxy resin paints can be used. Also, the epoxy equivalent is about 150 to 100
A value of 0 is preferred. If the epoxy equivalent is less than about 150, the coating will remain sticky and have poor drying properties, and will have an epoxy equivalent of about 100.
If it exceeds 0, it will become difficult to dissolve in the solvent, and it will be necessary to use a large amount of solvent, resulting in a low paint solid content.

That is, as a commercially available product, Epicoat 82
3, 834, 836, 1001, DX-255
(Product names manufactured by Shell Chemical Co., Ltd., Araldai) CY-2
60 (product name manufactured by Ciba Geigy), DER330, DER3
31, 337 (the above are product names manufactured by Dow Chemical Company),
Epicron 800 (trade name manufactured by Dainippon Ink Chemical Industries, Ltd.)
Bisphenol type ebony/(sealing resin; DEN431, etc.)
Phenol novolac type epoxy resin such as 438 (all trade names manufactured by Dow Chemical Company); Araldite CT-50
Polyglycol-type epoxy resins such as 8 (trade name manufactured by Ciba Geigy); ester-type epoxy +4 such as Epiclon 200 and Epiclon 400 (trade names manufactured by Dainippon Ink Chemical Industries, Ltd.) are representative examples of fats, etc. It will be done.

As the epoxy curing agent, compounds commonly used as curing agents for epoxy resins can be used. Examples include aliphatic polyamines, modified aliphatic polyamines, polyamide amines, aromatic polyamines, and modified aromatic polyamines. The mixing ratio of epoxy resin and epoxy curing agent is arbitrarily determined depending on the type of both, but usually (
Active hydrogen equivalent of curing agent/epoxy equivalent of epoxy resin)
When the value of is in the range of 0.5 to 1.0, the original performance of the epoxy resin can be exhibited.

Next, "Gilsonite" used in the present invention is a black-brown hydrocarbon compound produced from natural ore veins with a high softening point and low sulfur and gray content. Typical composition is 75-86% carbon and 8-15% hydrogen.
%, nitrogen content 1.5-5%, oxygen content 1-2%, ash content 4% or less, and its properties are an average molecular weight of 1300%.
~1800. Hardness (moh's 5cale) is about 2, penetration (25°C) is about 2, specific gravity is 1.03-1.06, and softening point is 130-190°C.

In the present invention, gilsonite is mainly used to improve rust prevention. In addition, due to its high softening point and hardness, it does not become sticky like petroleum-based asphalt, and it also contains almost no carcinogenic substances. The appropriate blending ratio of gilsonite is 50 to 200 parts by weight based on 100 parts by weight of the epoxy resin and epoxy curing agent.

If the proportion of Gilsonite exceeds the above range, the paint tends to thicken, which requires the use of a large amount of organic solvent, which lowers the solid content of the paint and makes the paint film brittle. This is not desirable because it becomes

On the other hand, if the blending ratio is less than the above range, drying properties will deteriorate, which is not preferable.

Next, the petroleum resin used in the present invention is an aliphatic petroleum resin in which a conjugated diene of a Cs fraction such as cyclopentadiene and 1,3-pencdiene is partially cyclopolymerized; Aromatic petroleum resin obtained by polymerizing C3 fractions such as styrene derivatives and indene from oil; the above C5
Copolymerized petroleum resin made by copolymerizing a fraction and a C3 fraction; Hydrogenated aromatic petroleum resin (alicyclic petroleum resin made by polymerizing sealant or dicyclopenk diene) It is a low molecular weight polymer with a number average molecular weight of about 500 to 2000.

It should be noted that if the molecular weight is higher than the above upper limit, the flexibility of the coating film will be reduced, which is not preferable.

In the present invention, by blending an appropriate amount of petroleum resin into the paint, the poor compatibility between gilsonite and epoxy resin can be overcome, and as a result, it becomes possible to form a paint. Furthermore, if a large amount of gilsonite is used, the paint tends to increase in viscosity, but by incorporating the petroleum oil, the viscosity of the paint can be appropriately lowered and the drying properties of the paint film can be improved.

The appropriate blending ratio of the petroleum resin is 20 to 180 parts by weight per 100 parts by weight of the epoxy (sealant and epoxy curing agent).If the blending ratio of the petroleum resin is too much than the above range, the coating film will deteriorate. It has disadvantages of poor flexibility and brittleness.On the other hand, if the blending ratio is less than the above range, the above effects cannot be obtained, which is also not preferred.

Next, the chlorinated polyethylene used in the present invention is:
Polyethylene is made into a solution or g2 solution of carbon tetrachloride, chloroform, trichloroethylene, etc. and subjected to a chlorination reaction at a temperature of 60°C or less, with a chlorine content of 15 to 40%,
A suitable material has a softening point of 30 to 100°C and an average molecular weight of 100,000 to 1,000,000.

Chlorinated polyethylene is softer than polyethylene itself, has a rubber-like appearance, is easily dissolved in solvents, and has a high resistance to coating film i! ? It can improve impact resistance and flexibility.

The appropriate blending ratio of the chlorinated polyethylene is 10 to 50 parts by weight based on 100 parts by weight of the epoxy resin and epoxy curing agent. It should be noted that if the blending ratio of chlorinated polyethylene is too much higher than the above range, the stability of the paint over time will deteriorate, which is not preferable. On the other hand, if the blending ratio is less than the above range, the coating film tends to lose its flexibility and become brittle, which is also not preferred.

The coating composition of the present invention (well, it contains the above-mentioned coating film-forming components as essential components. As the base coating film-forming component, if necessary, zinc phosphate, It is desirable to mix 30 to 50% by weight of pigments such as rust preventive pigments such as aluminum phosphate; extender pigments such as curk and calcium carbonate; and coloring pigments such as carbon black, as well as anti-sagging agents and leveling agents. It is desirable to incorporate small amounts of additives such as.

The coating composition of the present invention includes the above coating film forming components,
Further, an appropriate amount of an organic solvent such as toluene, xylene, methyl ethyl ketone, or butanol is blended, and the coating viscosity is preferably adjusted to a Ford cup #4 of 20 to 60 seconds.

The coating composition of the present invention is a two-component coating, and contains the above-mentioned epoxy resin and chlorinated polyethylene resin in the main component, and an epoxy curing agent in the curing agent component. , and other components may be blended into either the base agent or the curing agent component. However, it is mainly blended into the main ingredient.

In the present invention, the coating material can be produced by known methods such as kneading in a roll mill, pebble mill, ball mill, etc., but it is particularly preferable to use a closed ball mill because it can prevent volatilization of the solvent.

The iron pipe can be painted in almost the same way as conventional cool epoxy resin paints. That is, after surface treatment, the dry film thickness is 80μ or more, preferably 100μ or more, by means of airless spray, air spray, brush, etc.
Paint it to a thickness of about 200μ and let it dry naturally. In addition, in some cases, the iron pipe may be heated to 60 to 90°C in advance,
Alternatively, it may be forced to dry after painting.

<Effects of the Invention> The coating composition for iron pipes of the present invention has rust prevention, water resistance, and chemical resistance comparable to conventionally widely used tar epoxy resin coatings, but is superior to cool epoxy resin coatings. There are no disadvantages such as the poor working environment during painting, no elution of carcinogenic substances from the paint film, and no discoloration or cracking of the paint film in the summer. There is no need to repaint (repair) before shipping.
Furthermore, the handling time is within 8 hours even in winter, which has great practical value.

The present invention will be explained in more detail below using Examples. In the examples, "parts" and "%" are expressed on a weight basis.

Example 1 Bisphenol type epoxy resin [“Epicote #100
1J (product name manufactured by Shell Chemical Co., Ltd.); Epoxy equivalent 4
75, NV100%] 77 parts, Gilsonite 110 parts,
Aliphatic petroleum resin [Escolettes 3102j (trade name manufactured by Esso Chemical Co., Ltd.): average molecular weight 550, NV 100%
) 94.3 parts, 25 parts of chlorinated polyethylene [Superklon BLJ (trade name manufactured by Ichisaku Pulp Co., Ltd.); chlorine content 18%, weight average molecular weight 200,000], talc 330
14 parts of anti-sagging agent, 249 parts of Kijirole, 45 parts of doluol, and 40 parts of methyl ethyl ketone were kneaded in a pot mill to prepare a main ingredient.

In addition, polyamide resin solution (active hydrogen equivalent 450, NV6
5%), 100 parts of inbutanol, and 300 parts of triol were mixed in a disper to prepare a curing agent component.

90 parts of the base component and 1 part of the curing agent component thus obtained.
0 parts were mixed to prepare a paint.

Degreased and polished 1 mild steel plate (70X150XO, 8m
m) to a dry film thickness of 200μ,
It was dried at 20°C for one week.

i Questioned paint thickening properties, stability; semi-curing properties of paint films, bending resistance, impact resistance, adhesion, discoloration, water resistance, salt spray resistance, soda resistance, sulfuric acid resistance, Various cracking tests were carried out and the results were as shown in Table 1.

Example 2 Bisphenol type epoxy tree 11W Cr DER66
1J (trade name manufactured by Dow Chemical Company); Epoxy equivalent weight 47
5, NV100%] 113 parts, Gilsonite 100 parts,
Aliphatic petroleum resin [Finton 1525LJ (product name manufactured by Nippon Zeon Co., Ltd.); average molecular weight 1500, NV 100%
] 89 parts, chlorinated polyethylene "Super Chron BLJ
25i, 183 parts of talc, 90 parts of calcium carbonate, 7 parts of carbon black, 30 parts of aluminum phosphate pigment, 30 parts of anti-sagging agent, 14 parts of anti-cissing agent, 25 parts of pheasant
0 parts,) 50 parts of luol and 20 parts of methyl ethyl ketone were kneaded in a bot mill to prepare a main component. Also, amine adduct solution (active hydrogen equivalent: 336, NV55%)
A curing agent component was prepared by mixing 47 parts of inbutanol, 100 parts of inbutanol, and 253 parts of doluol in a disper.

90 parts of the base component and 1 part of the curing agent component thus obtained.
0 parts were mixed to prepare a paint.

The following is applied to a Liao mild steel plate in the same manner as in Example 1, dried,
Various tests were conducted.

Example 3 Bisphenol type epoxy It resin [r Epicote #82
8J (trade name manufactured by Shell Chemical Co., Ltd.); epoxy equivalent 190,
NV 10096] 40 parts, bisphenol type epoxy resin "Epicote #1001J 40 parts, Gilsonite 1
30 parts, aliphatic petroleum (Finton 1525Lj
L10 parts, chlorinated polyethylene "Super Chron BLJ"
25 parts and 271 parts of pheasant roll were mixed in a disper,
The main ingredient was created.

In addition, amine adduct solution (active hydrogen equivalent 221, NV7
0%) and 160 parts of Kijiroll were mixed in a disper to prepare a curing agent component.

90 parts of the base component and 1 part of the curing agent component thus obtained.
0B was mixed to prepare a paint.

Hereinafter, in the same manner as in Example 1, it was applied to a mild steel plate and dried,
Various tests were conducted.

Comparative Example 1 A paint was prepared in the same manner as in Example 1 except that the chlorinated polyethylene was removed, and it was applied to a mild steel plate, dried, and various tests were conducted.

Comparative Example 2 A paint was prepared in the same manner as in Example 1 except that the petroleum resin was omitted and the amount of gilsonite was increased by the same amount, and the paint was applied to a mild steel plate, dried, and various tests were conducted.

Comparative Example 3 In Example 1, gilsonite was used as the main component at 23
A paint was prepared by mixing 114 parts of the base component and 10 parts of the curing agent component using the same base component except that 0 part of the base component and 400 parts of Kijirole were used. Apply the following to the mild steel plate in the same manner.
It was dried and various tests were conducted.

Comparative Example 4 In Example 2, 270 parts of petroleum resin was used as the main component,
A paint was prepared by using the same base ingredients except for using 278 parts of Kijirole, and mixing 115 parts of the base ingredient and 10 parts of the curing agent component. Thereafter, it was similarly applied to a mild steel plate and dried, and various tests were conducted.

Comparative Example 5 A coating material was prepared using the same base ingredients as in Example 2 except that 100 parts of chlorinated polyethylene was used as the base ingredient, and 98 parts of the base ingredient and 10 parts of the curing agent were mixed.

Thereafter, it was similarly applied to a mild steel plate and dried, and various tests were conducted.

Comparative Example 6 260 parts of Coal Cool Pitch, 75 parts of bisphenol-type epoxy resin "Epicote #1001J, 25 parts of talc"
0 parts, calcium carbonate 100 parts, anti-sag agent 18 parts, doluol 110 parts, methyl ethyl ketone 90 parts and amine adduct solution (active hydrogen equivalent 336,
A curing agent component consisting of 140 parts of NV55%), 100 parts of inbutanol, and 760 parts of doluol (100:1
0) to prepare a conventional cool epoxy resin paint.

Thereafter, in the same manner as in Example 1, it was applied to a mild steel plate and dried, and various tests were conducted.

Note 1) Test to determine whether or not the initial viscosity of the main ingredient at 20°C is 90 KU or less increases to 100 KU or more after one month.○: No increase in viscosity, ×: Increase in viscosity.

Note 2) Put the main ingredient into a test tube and leave it for a while.

○: Not separated, ×: Separated.

Note 3) Test based on JIS-5400 (1
0mmφ) O: Pass ×: Fail Note 4) Test based on JIS-5400 (500
g.

2 inches, 30cm) ○: Pass ×: Fail Note 5) Test based on JIS-5400 (substrate test) Note 6) After 4 days of painting, put water on the paint film and use a watch to prevent it from evaporating. Tested under sunlight for one week (July).

○: No discoloration, ×: Discoloration Note 7) Test immersed in water for 2 months O: No abnormality, x Niblister or rust occurrence Note 8) Salt water spray 1000 hour test ○: No abnormality, × Nibblister or rust occurrence Note 9) 20-day immersion test in 5% caustic soda water O: No abnormalities, × Nibbly squeezing or rust occurrence Note 10) 20-day immersion test in 5% sulfuric acid water O: No abnormalities, ×: Blisters or rust observed) After painting, under sunlight 1 week exposure test (July) ○: No abnormality, ×: Cracks occurred Note 12) Test based on JIS-K-5400 (20°C) O: less than 10 hours, ×: 10 hours or more It is clear from Table 1 As can be seen, the coating composition of the present invention had excellent coating performance and passed the test for use on iron pipes.

On the other hand, in Comparative Example 1, which did not contain chlorinated polyethylene, the coating film lacked flexibility and had poor bending resistance and impact resistance.

On the other hand, in Comparative Example 5 in which chlorinated polyethylene was used in excess, the coating stability was poor and separation occurred.

Furthermore, in Comparative Example 2, which did not contain petroleum resin, the stability of the coating material was poor and the coating film performance was also poor. On the contrary, in Comparative Example 4 in which the petroleum resin was excessive, the coating film lacked flexibility and had poor bending resistance and +S resistance.

In addition, in Comparative Example 3 with excess gilsonite, the paint thickened and the coating workability was poor.

In addition, conventional tar epoxy resin paints not only contain carcinogenic substances, but also cause discoloration of the paint film during exposure tests in the summer.
A crack occurred.

Claims (1)

Scope of claims: (i) 100 parts by weight of an epoxy resin and epoxy curing agent having an epoxy equivalent of 150 to 1000 and having at least two or more epoxy groups in one molecule (ii) 50 to 200 parts by weight of gilsonite (iii) Petroleum resin with a number average molecular weight of 2000 or less 20~
A coating composition for iron pipes, comprising a coating film-forming component consisting of 180 parts by weight (iv) and 10 to 50 parts by weight of chlorinated polyethylene.