JPS60118756A - Hot water-resistant coating composition - Google Patents

Abstract

PURPOSE:To obtain titled composition of high solvent and acid resistance, free from development blisters or rust on exposure to hot water, for use in steel plates, etc., by incorporating epoxy resin with each specific amount of silane coupling agent, flaky talc containing oil of below a specific quantity, curing agent, etc. CONSTITUTION:The objective composition can be obtained by incorporating (A) 100pts.wt. on a solid basis, of epoxy resin (e.g. bisphenol type one with an epoxy equivalent 400-2,200) with (B) 10-40pts.wt. of silane coupling agent [e.g. gamma- glycidoxypropyl trimethoxysilane and/or N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane], (C) 250-500pts.wt. of flaky talc with an oil content <=40ml/100g, (D) 0-50pts.wt. of coloring pigment, and (E) 1-50pts.wt. of curing agent. EFFECT:Highly resistant to alkali.

Description

[Detailed description of the invention] The present invention relates to a coating composition with excellent hot water resistance.

More specifically, the present invention relates to a coating composition that can form a coating film having excellent properties such as not only hot water resistance but also solvent resistance, acid resistance, and alkali resistance when dried at room temperature.

In general, coatings on the inner surface of heat exchangers, the inner surface of seawater desalination equipment, the inner surface of tanks, etc. are required to be resistant to hot water. There was a defect that blistering or flaking of the coating film occurred during use.

By the way, many of the conventional hot water-resistant paints on the market use aliphatic polyacine or polyamide resin as a hardening agent in a main ingredient consisting of a liquid epoxy resin and a pigment such as an extender pigment. In general, the content of pigments such as extender pigments in the base agent was around % ION.

However, such paints are of little use, especially in environments with thermal gradients.

In this way, even in known commercially available paints, by increasing the content of pigments such as extender pigments in the base agent, it is possible to improve the hot water resistance and obtain a paint film that is somewhat resistant to blistering. On the other hand, if the pigment content exceeds 50% by weight, corrosive substances will easily permeate the paint film, causing rust to form on the base surface under the paint film in a short period of time, and rust juices to the paint surface. Various defects appear, such as those observed in

However, this tendency becomes more pronounced when a temperature gradient is applied to the painted surface.

Therefore, at present, it is extremely difficult to simultaneously prevent blistering and rusting in hot water resistance.

The present invention has been made to improve or eliminate the drawbacks of the prior art as described above, and of course prevents blistering in hot water resistance and rust on the base surface under the coating film.
Another object of the present invention is to provide a coating composition for obtaining a coating film having excellent chemical or physical properties such as acid resistance, alkali resistance, and solvent resistance.

That is, in the present invention, the 7-run force springing agent is 70 to qO parts by weight, and the oil absorption is 110 tnll/parts by weight of the epoxy resin solid content/θO.
Flat talc with a diameter of 10 θ2 or less, 2 left θ to left OOX; opening, 0 to 30 parts by weight of color pigment, and curing agent for engineering I xy resin/
-30 parts by weight of a hot water-resistant cover composition.

The niboxy resin used in the hot water-resistant coating composition of the present invention is a polymer having 3 or more polymers in its molecule. Any resin having an xy group may be used. However, from the viewpoint of hot water resistance and adhesion, the epoxy equivalent weight is 00~. It is preferable to use a bisphenol type edexy resin which is solid at room temperature of 2200 ml. If the epoxy ratio 1d does not match the θ0, blistering tends to occur in the hot water resistance test.If the epoxy equivalent exceeds 2:100, the solubility in solvents decreases and the viscosity of the solution decreases. Because the price also increases,
It tends to be difficult to increase the amount of chewing required for each body and face, and the crosslinking density tends to decrease. Therefore, the hot water resistance of the coating film is not significantly improved, and the usable temperature of the coated object tends to be lower. Examples of the bisphenol type epoxy resin include Epikote 10θ/, 100.2, manufactured by Yuka Shell Epoxy 5,
1003.100 ri.

1007; Manufactured by Asahi Kasei Corporation Product name Ar-RAt/ +6
Otori, 6 Otsu 7; Made by Showa Denko ■Product name: 0/.

4tolI; manufactured by Inu Nippon Ink Chemical Industry ■Product name: Epicron iogo, , 2oso, 4Loso, 7
osθ; Tobu Kasei @ parts master craftsman, ff)-to YD-0/
/.

θ/ri, 0/7; Dow Chemical Company product name DER6/
Examples include solid resins such as A47, A47, and A47. These resins are /f! It is possible to use it as a mixture of & or more types.

Further, the epoxy equivalent is dissolved in a necessary needle solvent before use.

Next, the silane coupling agent used in the coating composition of the present invention improves the blistering resistance, adhesion, etc. of the coating film, and at the same time has the effect of suppressing the flaking of the base surface under the coating film. It is something that you have.

The SS of the silane coupling agent used is in the range of 10 to 031 parts per 100 parts of the epoxy resin (solid content).

By using a silane coupling agent in the bond, the viscosity can be lowered without reducing the non-volatile content in the composition. Therefore, it is possible to reduce the viscosity of the composition to a degree that is impossible with conventional compositions. The amount can be increased. In other words, this is one of the factors that significantly improves the blistering resistance of the coating film.

In 1) above, if the amount of silane coupling agent used is less than 70 parts by weight, a coating film that simultaneously satisfies all of the blistering resistance, adhesion, and prevention of rust under the casing film. is obtained and separated. Furthermore, if the amount of silane cassilling agent used is small, a decrease in the pigment component content is unavoidable from the viewpoint of the viscosity of the composition and the wetting effect on the pigment, and therefore, the hot water resistance of the coating film decreases. The Urunisilane cassilling agent reacts with moisture in the air and is consumed when it is mixed into the composition or in the composition, so if the amount used is less than 70 parts by weight, the coating film will be damaged. This is undesirable because variations in performance are observed.

On the other hand, if the amount of the silane cassilling agent used exceeds 41 O parts by weight, the monofunctional compound will increase in the composition, and the crosslinking density of the coating film will become low (resulting in a decrease in coating film performance), so it is preferable. do not have.

Moreover, it is not preferable from an economic point of view since it requires the use of a large amount of expensive raw materials.

As the silane coupling agent used in the hot water-resistant coating composition of the present invention, there are commonly commercially available ones, such as r-glycidoxyprobyltrimethoxysilane, N
-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, r-aminopropyltrimethoxysilane,
r-(,2-aminoethyl)aminopropylmethyldimethoxysilane, β-(3,1it-epoxycyclohexyl)ethyl)! Examples include methoxysilane, which can be used as a mixture of 7 types or Ω or more types.

Particularly preferred silane coupling agents for various purposes of the present invention are γ-glycidoxypropyltrimethoxysilane and/or N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, such as Shin-Etsu Chemical Co., Ltd. Construction■
The product names include BM g03°, BM otsu03; Nippon Unica ■ product name A-/g7 +A-//20; Toray Silicon ■ product name SH oqo.

The extender pigment used in the hydrothermal coating composition of the present invention is flat talc with oil absorption = 'I Ome/ / 00 V or less, and the amount used is the same as that of the epoxy resin (solid content).
For a part of 700 weight I, 2. ! ;0 to 300 parts by weight.

If the oil absorption exceeds 10m1/10θ2, it is not preferable because a large amount of 0 to 300 parts by weight of the composition of the present invention cannot be used.

In addition, in the amount of flat talc used, it is 250
If it is not included in the parts by weight, the blistering resistance of the paint film will decrease, and if it is used in excess of 300 parts by weight, the workability of the paint will decrease and the resulting paint film will become porous. Therefore, it becomes difficult to prevent rust from forming under the paint film, which is not preferable in either case.

The flat talc has the characteristic that it can form a coating film with extremely superior hot water resistance compared to other extender pigments such as silica, barium sulfate, calcium carbonate, etc.

In the coating composition of the present invention, colored pigments may be used as pigments other than the flat talc, if necessary.

The coloring pigment is used in an amount of 0 to 30 parts by weight based on 700 parts by weight of the epoxy resin (solid content). Colored pigments in this range! When used in excess of f0 parts by weight,
This is not preferred because the hot water resistance of the resulting coating film decreases.

The coloring pigment may be appropriately selected from commercially available coloring pigments for ordinary paints, such as carbine black, iron oxide, and titanium oxide, according to the required coating performance such as hot water resistance and rust prevention. It is possible.

Furthermore, as the curing agent for epoxy resin used in the hot water-resistant coating composition of the present invention, amino compounds such as polyamide resin, amine adduct resin, and polyamine, which are usually used as curing agents for epoxy resin, can be used. be.

The curing agent for g and 3F xy resins is used in an amount of 7 to 50 parts by weight based on 100 parts by weight of the epoxy resin (solid content). In particular, the active hydrogen in the curing agent for epoxy resin is 0.6 to 7, based on the equivalent weight of epoxy groups in the epoxy resin.
．． It is preferable to use it in a ratio of 2 equivalents. If the amount of active hydrogen is less than 0.6 equivalent in the above range, the coating film will become soft, while the amount of active hydrogen will be less than 0.6 equivalent. - If the amount exceeds the equivalent amount, the hot water resistance of the coating film will decrease and the coating film will become discolored easily, so any S combination is not very preferable.

In addition, when considering the balance of hot water resistance, normal temperature drying property, hardness, etc. of the obtained coating film, the above range is F I? xy group/
In view of the present invention, the optimum amount of active hydrogen is 0.7 to 7.0 equivalents.

In addition, among the amino compounds as the curing agent, for the purpose of the present invention, that is, to improve the hot water resistance, solvent resistance, acid resistance, and alkali resistance of the coating film, and to obtain a coating film without discoloration, More preferred is an amine compound containing xylylene diamine as one component.

The amine compounds include polyamide resins containing xylylene diamine as one component, amine adduct resins to which xylylene diamine is added, polyamines, the above amino compounds containing xylylene diamine as one component, and other amino compounds. (I-lyamide resin to amine adduct resin or polyamine), etc. can be mentioned.

Examples of these curing agents include Sanmide x-20θ0, X-, 2θ00A manufactured by Sanso Kagaku Kogyo (■).

x-, 10/! ;, X-2700, etc.; Product name: FujiCure X-θQ/, X-003, manufactured by Gishi Kasei Kogyo.

X-0030, +&θθ0, #! ;30θ, etc.;Product name: ADEKA HARDNER EH2/2゜EH2, manufactured by Asahi Denka Kogyo ■
λ0. EH24'0. EH, 270, etc., and these are used as a mixture of 7 types or 2 or more types. These epoxy resin curing agents are also dissolved in a required amount of solvent before use.

Furthermore, the hot water-resistant coating composition of the present invention may contain, as necessary, additives commonly used in paints such as antifoaming agents, thixotropic agents, and dispersants, as well as other compatible resins. , extender pigments, reactive diluents, plasticizers, hardening accelerators, etc. other than those mentioned above may also be used in small amounts.

The hot water resistant coating composition of the present invention comprises (I) an epoxy resin;
A two-component composition in which a silane coupling agent, flat talc, and a solvent are kneaded together as a main ingredient, and a hardening agent solution for the resin is mixed at the time of use, or (11) 24? A part of each of the epoxy resin, silane cassilling agent, and/or flat talc is kneaded with a solvent to form the main ingredient, while the remainder of each of the epoxy resin curing agent, silane cassilling agent, and/or flat talc is kneaded with a solvent. It is a two-component composition in which the curing agent is kneaded with a solvent and the two are mixed at the time of use. In any case, when mixing the pigment components, it is necessary to conflate them using a three-reeler, etc., and the particle size is reduced to a particle size of less than the left θμ, more preferably less than 2Sμ, using the tube B method of J I S-, S-+θ0. It is preferable to use it in a dispersed manner.

The thus obtained hot water-resistant coating composition of the present invention can be applied directly onto the prepared substrate or as a coating material such as an inorganic zinc-rich paint or an organic zinc-rich paint.
A dry film thickness of 30 to 7
000μ by a conventional coating method such as air spray, airless spray, or brush, and is dried by layer temperature or forced drying to obtain the desired coating film.

As mentioned above, the coating film obtained from the hot water-resistant coating composition of the present invention using a specific amount of a silane coupling agent and flat talc in combination with an epoxy resin is particularly resistant to oxygen, water, and other substances in a hot water resistance test. This prevents deterioration of the interface with the coated object due to penetration of the paint film by erodible substances, such as spraying and rusting, and also provides excellent paint film properties such as acid resistance, alkali resistance, and solvent resistance. be.

Therefore, the composition of the present invention is an optimal coating composition for coated objects that require hot water resistance, such as heat exchangers, seawater desalination equipment, tanks, power generating units, and chemical solants.

The details of the present invention will be explained below using examples.

"Part" or "%" indicates "part by weight" or "% by weight".

Example / (Main agent) 70% xylene solution of solid bisphenol type epoxy resin (epoxy equivalent left θ to left 0 θ) / '+, 2.9
(resin solid content 700 parts), γ-glycidoxyprobyltrimethoxysilanco3. θ part, oil absorption jlk, 37fn
! , / / 00 f flat 1 Luk 31,0.0 parts,
0.7 parts of Carpin black, 15R xylene, 29.0 parts of O*L ethyl cellosolve, and 06 parts of additives such as an antifoaming agent and a thixotropic agent were kneaded in a 4-lar to form a main ingredient.

(Curing agent) Modified aliphatic polyamine containing xylylene diamine as one component [manufactured by Fuji Kasei Kogyo ■ Part name Fuji Cure #Left 00θ:
Active hydrogen equivalent 100] 20.7 parts, xylene/o, o
+r++' and s and o parts of isobutanol were combined to form a curing agent.

When using the main agent and curing agent, qlLt, 7: -5,3(
The coating composition of the present invention was obtained by mixing at a ratio of (weight ratio).

Example (base resin) Solid bisphenol type epoxy resin (epoxy equivalent: 3
70% xylene solution of 0 to 300) / 11.2.9 parts (resin solid content 100 parts), γ-glycidoxypropyltrimethoxysilanco 0.0 part, oil absorption 37 mt / 100
y flat puffer fish 00. θ section, carbon blank 0-
7 parts, xylene 7S, θ parts, ethyl cellosolve, 29.
Part 0, additives such as an antifoaming agent and thixotropic agent, and part Otsu were kneaded with a roller to form a main ingredient.

(Curing agent) Add 000 to the Fuji Cure #. 20.7 parts, N-β-
5.0 parts of (amine ethyl)-r-aminopropyltrimethoxysilane, 3.0 parts of xylene, and 5.0 parts of n-butanol were mixed to form a curing agent.

When using, add 9 Lq of main agent and curing agent: 5. / (weight ratio) to obtain a hot water-resistant coating composition of the present invention.

Example 3 (Main agent) Solid bisphenol coating I xy resin (epoxy Tosho G7
5-97) 30% butylcarpitol solution I/10
．． 0 parts, solid bisphenol type epoxy resin (epoxy equivalent 1I-30-00) (r) 70% xylene solution/
, /llt, 3 parts [total solid content of epoxy resin 700 parts], γ-glycidoxyprobyltrimethoxysilane 2
jt, 0 parts, flat talc with oil absorption of 3 tri//θθt, 3Sθ, θ parts, titanium oxide 5.0 parts, xylene 7
S, θ part, ethyl cellosolve, 29.0 parts and antifoaming agent,
Additives such as thixotropic agents 2. Otobe was kneaded with a roller and used as the main ingredient.

(Curing agent) Modified aliphatic polyamine containing xylylene diamine as one component [trade name Sanmide x-xois manufactured by Sansho Kagaku Kogyo ■
: Active hydrogen Tosode gO] 72.3 parts, curing accelerator [Seiko Kagaku <-> Product name: Seikol TDMPI/, θ part, flat talc with oil absorption of 3 Ome//θ02, 20.0 parts, xylene 70.0 parts of isobutanol and 3.0 parts of isobutanol were kneaded with a roller and used as a hardening agent.〇-When used, the main ingredient and hardening agent were mixed in a ratio of 93.0:7. The hot water-resistant coating composition of the present invention was obtained by mixing in the ratio of θ (weight ratio). Example 1 (main ingredient) Solid bisphenol type epoxy 4f+JJ]W (epoxy equivalent/7 left 0-2200) glue θ% cellosol Zuacetate and xylene mixed solution (solvent mixing ratio /:/) 25.0
72 g of a 7% xylene solution of a solid bisphenol type epoxy resin (epoxy resin yso-soo), 72 g of a 7% xylene solution of solid bisphenol type epoxy resin (total solid content of epoxy resin 10.0 parts), 23. 0 parts, 330.0 parts of flat talc with oil absorption of 3g/100#, titanium oxide S, θ parts, xylene 7 parts, θ parts, ethyl cellosolve, 2 q, o parts and v antifoaming agent, thixotropic agent Additives λ and Otsube were kneaded with a roller to form the main ingredient.

(Curing agent) Modified aliphatic polyamine containing xylylene diamine as one component [Mudenka Kogyo @ product name ADEKA HARDENER-EH-, 2/
λ: active hydrogen equivalent g0]/Ω, 6 parts, xylene 7.0 parts, and isobutanol 5.0 parts were mixed to form a curing agent.

When using, mix the main agent and hardening agent at 94%. ．． 2:3. g (weight ratio) to obtain a hot water-resistant coating composition of the present invention.

Comparative example/ Solid bisphenol mold d? Oxy resin (epoxy resin 17
7 parts% xylene solution of 1'l/, left θ to left θ0)/11
．． ．． 2.9 parts (resin solid content 700 parts), 23.0 parts of γ-glycidoxyzolopyltrimethoxysilane, oil absorption side',
'l / ml / / talc 3 k 0 of 0θ2
．． 0 part, carbon black 0.7 part, titanium oxide s part,
73.0 parts of xylene, 29.0 parts of ethyl cellosolve, and additives such as an antifoaming agent and a thixotropic agent, and 2 parts were kneaded with a roller, but the composition became lumpy and a coating composition could not be obtained. .

Comparative Example λ ~ Table on the left - After obtaining the base resin in the same manner as Example /, the same curing agent as Example / was mixed at the same mixing ratio, and the coating composition of Comparative Example was prepared. Comparative tests were conducted on the obtained four compositions of Example 0 and Comparative Example a to left as follows.

The results are shown in Table C.

/) Preparation of comparison test piece Test piece = Sandblasting steel plate coating Equipment Air spray coating Number of coatings: / 0μ// Coating or 3 times Paint dry! Leave it at room temperature for 7 days. When painting, use xylene/ethyl cellosolve = g/
The air spray coating viscosity was adjusted to ':J4 using a mixed solvent of 2.

2) Comparative test The evaluation of the paint film was in accordance with the Japan Paint Inspection TFit Association's 1 Paint Film Evaluation Criteria.

(a) Lining tester trial 1 (film thickness 3θ0 μ) ■ Yamazaki Seiki Research Institute 42 Attach the test piece to the lining tester and use pure water and 3% saline, each at 9°C to produce 7 cracks or so-called We measured the number of days until

(b) Thermal gradient test (1 range thickness 4 left θμ) After pack-sealing the superior test piece, the test coating side was brought into contact with g5C pure water or 3% saline, and the pack-seal IU1 was heated to 3θC.
What happens when it comes in contact with tap water and causes blisters or clear water? It was measured.

(C) etc. tl;A PJ +1 test Ol'JI130
The test piece was completely immersed in pure water at 70C or 3% saline at 60C for 6°F, and then allowed to stand until blisters or rust appeared.

(d) One stroke resistance (11 sounds 1 zo 300μ) SOC 10
The test piece was immersed in % sulfur and blistered.1. ,! 7 I
J″-The number of days until occurrence was measured.

(e) Alkali resistance (11 center thickness 300μ) 50C 3
A test piece was immersed in % ammonia water, and the number of days until 7 creases occurred was measured.

(a) Solvent resistance (film thickness 30θμ) A test piece was immersed in 700% methanol at 0C on the left, and the number of days until blistering occurred was measured.

From the above ratio test result table, it is clear that the coating film obtained from the hot water resistant temporary composition of the present invention does not cause blistering or rust in hot water resistant tests such as the 2-inning tester test, thermal gradient test, and isothermal immersion test. Moreover, it showed very excellent results in terms of acid resistance, alkali resistance, and solvent resistance.

On the other hand, in the comparative example in which the oil absorber was 1IOd/7009 or more of talc, a coating composition could not be obtained, and a coating film obtained from a composition in which the amount of silane cassilling agent added was outside the range of the present invention ( Comparative examples ko and 3) and flat talc-added u
In each of the above tests, ruts were obtained from compositions outside the scope of the present invention (Comparative Examples No. 5 and No. 5).
Rust etc. occurred.

Claims (4)

[Claims] (1) For 100 parts by weight of epoxy resin solid content, 0 parts by weight of silane coupling agent / θ ~ 0, oil absorption amount 'I O
ml / / Flat talc below 00V 2! A hot water-resistant coating composition containing 7 to 50 parts by weight of a curing agent for epoxy resin, 50 parts by weight of a colored pigment Q-1. (2) Niboxy resin has an epoxy equivalent of 00 to . 2.
200 bisphenol type epoxy resin. (3) Claim (1) wherein the silane coupling agent is r-glycidoxyzorobyltrimethoxysilane and/or N-β-(aminoethyl)-γ-aminoglopyltrimethoxysilane. The hydrothermal hydrothermal composition described above. (4) The hot water-based seedling composition according to claim (1), wherein the curing agent for niboxy resin is an amino compound containing xylylene diamine as one component.