JPH0320375A - Coating composition for iron pipe - Google Patents

Abstract

PURPOSE:To obtain the subject compsn. contg. no carcinogen, being inexpensive and free from discoloration and cracking, and having excellent water resistance, rustproof characteristics, etc., by preparing a coating component from each specified epoxy resin, acrylic resin, petroleum resin, epoxy curing agent and xylene resin. CONSTITUTION:The subject composition compriser a coating component consisting of 100 pts.wt. (hereinbelow described as pts.) epoxy resin with two or more epoxy groups in the molecule and an epoxy equivalent of 150-1,000 (e.g. Epicote 1,001) and an epoxy curing agent (e.g. a polyamide), 50-190 pts. acrylic resin with a glass transition temp. of 30-80 deg.C and a hydroxyl value of 40-160, 20-200 pts. petroleum resin with a number-average mol.wt. of 2,000 or smaller (e.g. Escolet 3,102) and 10-70 pts. xylene resin (e.g. Nikanol LLL).

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a paint composition for iron pipes to obtain a coating film that does not contain carcinogenic substances and is resistant to discoloration, cracking, etc. be.

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

Problems to be Solved by the Invention> However, tar, that is, coal tar pitch, contains polyhex, which contains carcinogenic substances, and therefore does not comply with the recommendations of the WHO, etc. Therefore, there has been a desire to develop a paint to replace cool epoxy resin paints. However, since there was no alternative paint that was inexpensive and had excellent film performance, tar-epoxy resin paints had no choice but to be used, even though they were known to have the drawbacks mentioned above. That was the actual situation.

In addition, cool epoxy resin paints are used during the drying process of the paint film.
If exposed to strong ultraviolet rays during the summer, the product may often turn brown or crack, and it may be necessary to reapply with alkyd resin paint, etc. to maintain its beauty before shipping. there were.

In view of the current situation, the inventor of the present invention has conducted extensive research and found that it 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 paint assembly for iron pipes that provides a coating film comparable to that of tar epoxy resin paints, and completed the present invention.

(Means for Solving the Problems) That is, the present invention provides (i) an epoxy resin having at least two epoxy groups in one molecule and an epoxy equivalent of 150 to 1,000, and 100 parts by weight of an epoxy curing agent (ii) glass Transition temperature 30~80℃, hydroxyl value 40~
160 acrylic resin 50 to 190 parts by weight (iii) Petroleum resin 2 with a number average molecular weight of 2000 or less
0 to 200 parts by weight (iv) xylene resin Contains a coating film-forming substance consisting of 10 to 70 parts by weight, and further contains mineral fillers such as extender pigments, antirust pigments, and coloring pigments, various additives, etc. The present invention relates to a coating composition for iron pipes which is dissolved in a suitable organic solvent.

The present invention will be explained in detail below.

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 becomes difficult to dissolve in the solvent, and it is necessary to use a correspondingly large amount of solvent, resulting in a low coating solid content.

In other words, Ebicoat 8 is commercially available.
28, 834, 836, l001, DX-25
5 (Product names manufactured by Shell Chemical Co., Ltd., Araldai) GY-
260 (product name manufactured by Ciba Geigy), DER330, DER 331, DER 337 (product names manufactured by Dow Chemical),
Ebicuron 800 (trade name manufactured by Dainippon Ink Chemical Industries, Ltd.)
Bisphenol type epoxy resin such as DEN43L 4
Phenol novolac type epoxy resin such as 38 (trade name manufactured by Dow Chemical Company); Araldite CT-508 (
Typical examples include polyglycol type epoxy resins such as Ciba Geigy Co., Ltd. (trade name); ester type epoxy resins such as Epiclon 200 and Epiclon 400 (all trade names manufactured by Dainippon Ink & Chemicals Co., Ltd.).

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.

The acrylic resin used in the present invention is blended in order to improve the drying properties of the coating film and to obtain a coating film that is less likely to cause cracks and has good adhesion.

Therefore, the acrylic resin needs to have a glass transition temperature (hereinafter referred to as rTgJ) of 30 to 80°C and a hydroxyl value of 40 to 160.

When Tg is less than 30°C, drying properties are poor and stickiness is observed, while when Tg exceeds 80°C, physical properties such as bending resistance deteriorate, which is not preferable.

In addition, when the hydroxyl value is less than 40, the compatibility with other substances such as epoxy resin is poor, and the storage stability of the paint is poor.On the other hand, when the hydroxyl value exceeds 160, the water resistance and moisture resistance are poor.
Both are unfavorable because they tend to cause blisters in the coating film.

As an acrylic resin, hydroxyalkyl esters of α, β-monoethylenically unsaturated carboxylic acids such as (meth)hydroxyethyl acrylate and hydroxyprobyl (meth)acrylate are essential components, and ( (meth)acrylic acid esterified with alkanols such as methyl, ethyl, proyl, 2-ethylhexyl, etc.
Acrylic acid ester; α,β-monoethylenically unsaturated carboxylic acids such as (meth)acrylic acid and itaconic acid; (
An amino group-containing monoethylenically unsaturated compound such as meth)acrylamide or N-methylol(meth)acrylamide; and each monomer such as styrene or (meth)acrylonitrile, so that the Tg1 hydroxyl value of the resulting acrylic resin falls within the above range. Examples include those produced by a conventional solution polymerization method using mixed monomers formed by appropriately combining them.

These acrylic resins, like coal tar pitch, petroleum-based asphalt, and gilsonite, are carcinogenic substances3.
, 4-pentsupyrene at all, and has excellent dry fish properties. The appropriate blending ratio of the acrylic resin is 50 to 190 parts by weight based on 100 parts by weight of the epoxy resin and epoxy curing agent. If the blending ratio of the acrylic resin is too high than the above range, it is necessary to use a large amount of organic solvent to dissolve the acrylic resin, which is not preferable because the solid content of the paint decreases accordingly. On the other hand, if the blending ratio is less than the above range, the above effects cannot be achieved, for example, the drying properties become poor and it takes a long time to handle the iron pipe, which is not preferable.

The petroleum resin used in the present invention is an aliphatic petroleum resin in which conjugated dienes of Cs fraction such as cyclobentadiene and 1,3-pentadiene are partially cyclopolymerized; Aromatic petroleum resin obtained by polymerizing a Cs fraction such as a styrene derivative or indene; Copolymerized petroleum resin obtained by copolymerizing the above C fraction and a Cs fraction; Resin obtained by hydrogenating an aromatic petroleum resin It is a low molecular weight polymer with a number average molecular weight of about 50° to 2000, such as an alicyclic petroleum resin obtained by polymerizing dicyclopentadiene or dicyclopentadiene. If the molecular weight is higher than the above upper limit, the flexibility etc. of the coating film will decrease, which is not preferable.

In the present invention, by blending an appropriate amount of petroleum resin into the paint, the viscosity of the paint can be lowered appropriately, so even if the solid content of the paint is increased, an appropriate viscosity can be obtained, and thick film properties can be imparted. can.

The blending ratio of the petroleum resin is 20 to 200 m per 100 parts by weight of the epoxy resin and epoxy curing agent! i
The quantity is appropriate. If the blending ratio of petroleum resin is too much than the above range, the coating film will have a disadvantage of poor flexibility and brittleness. On the other hand, if the blending ratio is less than the above range, the above-mentioned effects cannot be obtained, which is also not preferable.

The xylene resin used in the present invention is mainly a reaction product of meta-xylene and formaldehyde, and has an average molecular weight of about 300-600, a reactive group equivalent of about 180-300,
Oxygen content 8-15% by weight, viscosity (50°C) 80-6
00 cps is suitable. When this is used, the compatibility with acrylic resins, epoxy resins, and petroleum resins becomes even better.

In the present invention, the xylene resin improves the flexibility of the coating film, improves impact resistance and flexibility, and in addition, the terminal methylol group of the xylene resin has high reactivity with the epoxy curing agent. It also has the effect of increasing hardness.

The appropriate blending ratio of the xylene resin is about 10 to 70 parts by weight based on 100 parts by weight of the epoxy resin and epoxy curing agent. If the blending ratio of the xylene resin is too much than the above range, the drying properties of the coating film will be poor and tackiness will remain, 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 paint assembly of the present invention has the above-mentioned coating film form or part as an essential component. Other anti-corrosion pigments such as zinc phosphate and aluminum phosphate to improve coating film hardness and anti-rust power, etc. as required for coating film formation; extender pigments such as talc and calcium carbonate; coloring pigments such as carbon black; It is desirable to blend pigments such as 30 to 50% by weight in the solid content of the paint, and it is also desirable to blend small amounts of additives such as anti-sagging agents and leveling agents.

The paint assembly of the present invention has the following coating film shape:
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 Ford cup #4 in 20 to 90 seconds.

The paint composition of the present invention is a two-component paint, and contains the above-mentioned epoxy resin and xylene resin in the main component, and an epoxy curing agent in the curing agent component. Other parts may be added to either the main ingredient or the curing agent. However, it is desirable to mainly incorporate it into the main ingredient.

In the present invention, the coating material can be manufactured using known methods such as roll mill, pebble mill, and bottle mill. Although it can be produced by kneading in a Lumil or the like, it is particularly preferable to use a closed type Pall Mill to prevent volatilization of the solvent.

The iron pipe can be painted in almost the same way as conventional tar epoxy resin paint.

That is, after surface treatment, the coating is applied using an airless sprayer, a brush, or the like to a dry film thickness of 80 μm or more, preferably about 100 to 200 μm, and allowed to air dry. In addition, depending on the case, the iron water pipe should be pre-installed at 60 to 9
The coating may be heated to 0°C or forced dry after coating.

Effects of the Invention The steel pipe paint assembly of the present invention is comparable in rust prevention, water resistance, and chemical resistance to tar epoxy resin paints that have been widely used in the past, and is free from the drawbacks of tar epoxy resin paints. There is no bad working environment during painting, no drying properties such as stickiness, no elution of carcinogenic substances from the paint film, and no discoloration or cracking of the paint film in the summer. Therefore, the paint assembly for iron pipes of the present invention is repainted (
There is no need for repairs, and the handling time is less than 8 hours even in winter, so it has great practical value.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the examples, "parts" and "%" are expressed on a weight basis. [Preparation of acrylic resin face] Monomer compositions shown in Table 1 (numbers in the table are "parts") were solution polymerized according to a conventional method to prepare acrylic resin varnishes A-G having the characteristics shown in the lower column of Table 1. did. In addition, a commercially available acrylic resin varnish H-L was used.

Example 1 Bisphenol type epoxy resin [“Epicote #1 0
0 1J (trade name manufactured by Shell Chemical Co., Ltd.); Epoxy equivalent 475, NVIOO%] 77 parts, acrylic resin varnish A 220 parts, aliphatic petroleum resin [(Escolefu 310)
2J (trade name manufactured by Esso Chemical Co., Ltd.); average molecular weight approximately 55
0, NV 100% 394.3 parts, xylene resin [
“Nicanol LLLJ (product name manufactured by Mitsubishi Gas Chemical Co., Ltd.)
; average molecular weight 340, reactive group equivalent weight 275, NVIOO
%], 330 parts of talc, 4 parts of anti-sagging agent, 139 parts of xylene, 45 parts of toluene, and 40 parts of methyl ethyl ketone were kneaded in a pot mill to prepare a main ingredient.

On the other hand, polyamide resin solution (active hydrogen equivalent 450, NV
65%), 100 parts of inbutanol, and 300 parts of triol were mixed in a disper to prepare a hardening agent.

90 parts of the base agent and 1 part of the hardening agent obtained in this way
0 parts were mixed to prepare a paint.

Degreased and polished mild steel plate (70X150X0.8
Coat the paint to a dry film thickness of 200 μm.
It was dried at 20°C for one week.

Residual residue on heating during coating, stability of the resulting paint; semi-curing properties of the coating film, bending resistance, impact resistance, adhesion, discoloration, water resistance, salt spray resistance, caustic soda resistance, sulfuric acid resistance , various tests for crack resistance and varnish compatibility were conducted, and the results were as shown in Table 2.

Example 2 Bisphenol type epoxy resin C r DBR661
J (trade name manufactured by Dow Chemical Company); epoxy equivalent weight 475
, NVIOO%] 113 parts, acrylic resin varnish B2
00 parts, aliphatic petroleum resin ["Quinton 1525LJ
(Product name manufactured by Nippon Zeon Co., Ltd.); Average molecular weight 1500
, NVIOO%] 89 parts, xylene resin "Nicanol L
LLJ 25 parts, talc 183 parts, calcium carbonate 90 parts, carbon black 7 parts, aluminum phosphate pigment 30 parts
part, 30 parts of anti-sag agent, 14 parts of anti-scalding agent, 150 parts of xylene, 50 parts of toluene, 2 parts of methyl ethyl ketone
0 parts were kneaded in a pot mill, and a certain amount of the main ingredient was added.

On the other hand, amine adduct solution (active hydrogen equivalent 336, NV
55%) and 253i% of inbutanol IOOL}luol were mixed in a disper to prepare a certain amount of curing agent.

90 parts of the base agent and 1 part of the hardening agent thus obtained
Part O was mixed to prepare a paint of m.

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

Example 3 Bisphenol type epoxy resin [“Epicote #828
J (trade name manufactured by Shell Chemical Co., Ltd.); Epoxy equivalent: 190
, NV100%] 40 parts, bisphenol type epoxy resin "Epicoat #1 0 0 1J 40 parts, acrylic resin varnish H260 parts, aliphatic petroleum resin "Quinton 1
525LJ 110 parts, xylene resin "dicanol LLL
25 parts of J and 141 parts of xylene were mixed in a disburr, and the main ingredient was mixed.

On the other hand, amine adduct solution (active hydrogen equivalent 221, NV
7 0915) -5 2 0R, Wish ct-160
A portion of the hardening agent was added by mixing the two parts using a disper.

90 parts of the base agent and 1 part of the hardening agent obtained in this way
0 parts were mixed to prepare a paint.

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

Example 4 A paint was prepared in the same manner as in Example 1 except that acrylic resin varnish C was used instead of acrylic resin varnish A, and various tests were conducted.

Example 5 A paint was prepared in the same manner as in Example 1 except that acrylic resin varnish D was used instead of acrylic resin varnish A, and various tests were conducted.

Example 6 A paint was prepared in the same manner as in Example 1 except that acrylic resin varnish E was used instead of acrylic resin varnish A, and various tests were conducted.

Example 7 A paint was prepared in the same manner as in Example 1 except that acrylic resin varnish L was used instead of acrylic resin varnish A, and various tests were conducted.

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

Comparative Example 3 The same base ingredients as in Example 1 were used except that 460 parts of acrylic resin varnish A and 170 parts of xylene were used as the base ingredients, and 114 parts of the base agent and 1 part of the curing agent were used.
0 parts were mixed to make a paint. The coating was applied to a polished mild steel plate in the same manner, dried, and various tests were conducted.

Comparative Example 4 In Example 2, 270 parts of petroleum resin was used as the main agent,
A paint was prepared by using the same proportion of the base agent except that xylene was changed to 278 parts, and mixing 115 parts of the base agent and 10 parts of the curing agent. The coating was applied to a polished mild steel plate in the same manner and dried, and various tests were conducted.

Comparative Example 5 In Example 2, a certain amount of xylene resin was used as the base resin at 110%
A paint was prepared by using the same proportions of the base agent except for the following: 98 parts of the base agent and 10 parts of the curing agent. The coating was applied to a polished mild steel plate in the same manner and dried, and various tests were conducted.

Comparative Example 6 Coal tar pitch 260 parts, bisphenol type epoxy resin "Epicor #1001" 75N, talc 250 parts
100 parts of calcium carbonate, 18 parts of anti-sagging agent, 110 parts of toluene, and 90 parts of methyl ethyl ketone and an amine adduct solution (active hydrogen equivalent: 336, N
V55%N40 parts, inbutanol 100 parts, toluene 760 parts and some hardening agent (100:
1.0) to prepare a conventional tar epoxy resin paint.

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

Comparative Example 7 A paint was prepared in the same manner as in Example 1 except that acrylic resin varnish (2) was used instead of acrylic resin varnish A, and various tests were conducted.

Comparative Example 8 A paint was prepared in the same manner as in Example 1 except that acrylic resin varnish J was used instead of acrylic resin face A, and various tests were conducted.

Comparative Example 9 A paint was prepared in the same manner as in Example 1 except that acrylic resin varnish F was used instead of acrylic resin varnish A, and various tests were conducted.

Comparative Example 10 A paint was prepared in the same manner as in Example 1 except that acrylic resin varnish G was used instead of acrylic resin varnish A, and various tests were conducted.

Comparative Example 11 A paint was prepared in the same manner as in Example 1 except that acrylic resin varnish K was used instead of acrylic resin varnish A, and various tests were conducted.

Note 1) Note 2) Note 3) Note 4> Note 5) Note 6〉 Note 7) Heating residue during painting ○: 50% or more ×: less than 50% Put the main agent Bobun into a test tube and leave it for one week.

○: Not separated, ×: Separated.

Test based on JIS-K-5400 (10au++φ) ○: Pass, X: Fail.

Test based on JIS-K-5400 (500g, 1/2 inch, 30cm) ○: Pass,
×: Fail.

After painting, test based on JIS-K-5400 after being exposed to sunlight for 1 year (checkerboard test) 4 days after painting, water was placed on the paint film and exposed to sunlight with a watch glass to prevent evaporation. Exposure for 1 week (July) Test ○: No discoloration, X: Discoloration.

2-month immersion test in water ○: No abnormalities, ×゛: Blisters or mackerel formation Note 8) Salt water spray 1000 hour test ○: No abnormalities, ×: Blisters or rust formation Note 9) 20-day immersion test in 5% caustic soda water ○ : No abnormality, ×: Blistering or rusting Note 10) 20-day immersion test in 5% sulfuric acid ○: No abnormality, ×: Blistering or rusting Note 11) After painting, exposed to sunlight for 1 year! (July) Test ○: No abnormality, ×: Cracks occurred Note 12) Test based on JIS-K-5400 (20℃> ○: Less than 10 hours, X: 10 hours or more Note 13) Only a certain amount of varnish was applied to the glass plate to check compatibility.

○: M is completely transparent, ×: film is cloudy. As is clear from Table 1, the paint assembly of the present invention had excellent coating film performance and passed the test for use on iron pipes.

On the other hand, in Comparative Example 1 which did not contain xylene resin, the coating film lacked flexibility and had poor bending resistance and impact resistance. On the other hand, in Comparative Example 5, in which the xylene resin was present in excess, the coating film remained sticky.

Furthermore, Comparative Example 2, which did not contain an acrylic resin, had poor coating stability, slow drying properties, and poor bending resistance. On the other hand, in Comparative Example 3 in which the acrylic resin was excessive, it was necessary to increase the amount of solvent, the solid content of the paint was low, making it difficult to form a thick film, and furthermore, blisters occurred in the salt spray test.

Furthermore, in Comparative Example 4 in which the petroleum resin was excessive, the coating film lacked flexibility and had poor bending resistance, impact resistance, etc.

Furthermore, Comparative Example 6, which is a conventional tar epoxy resin paint, not only contained carcinogenic substances, but also caused discoloration and cracks in the paint film.

Furthermore, in Comparative Example 7 and 1L, in which an acrylic resin with a low hydroxyl value was used, the stability of the paint and the compatibility of the varnish were poor. On the contrary, Comparative Example 9, which used an acrylic tree with a large hydroxyl value, had poor water resistance.

Furthermore, Comparative Example 8 using an acrylic resin with low TH had poor drying properties. On the contrary, Comparative Example 10, which used an acrylic resin with a high Tg, had poor bending resistance and impact resistance.

Claims (1)

Scope of Claims: (i) 100 parts by weight of an epoxy resin having an epoxy equivalent of 150 to 1000 and an epoxy curing agent having at least two epoxy groups in one molecule (ii) Glass transition temperature of 30 to 80°C, hydroxyl value 40~
160 acrylic resin 50 to 190 parts by weight (iii) Petroleum resin having a number average molecular weight of 2000 or less 20 to 190 parts by weight
A coating composition for iron pipes, comprising a coating film forming component consisting of 200 parts by weight (iv) and 10 to 70 parts by weight of a xylene resin.