JPS598770A - Coating material composition for coated steel plate - Google Patents

Abstract

PURPOSE:The titled composition, containing a polyester resin consisting of a specific acid component and a polyol component and an alkyl-etherified aminoformaldehyde resin, having improved processability and weather resistance, and capable of assuming improved coating film appearance. CONSTITUTION:A composition containing (A) 95-70pts.wt. polyester resin consisting of (i) 80-30mol% isophthalic acid, 20-45mol% 4-12C aliphatic dicarboxylic acid, 0'25mol% terephthalic acid and 0-5mol% tri- - polyfunctional polycarboxylic acid as an acid component and (ii) 92-100mol% neopentyl glycol and 0- 8mol% tri- - polyfunctional polyol and (B) 5-30pts.wt. alkyl-etherified aminoformaldehyde resin.

Description

[Detailed Description of the Invention] The present invention has excellent processability and weather resistance. The present invention relates to a coating composition for coated steel plates that exhibits a coating film appearance with excellent gloss and brightness.

What is the characteristic of water intake as a painted steel sheet?

It has excellent workability such as press working. Currently used paints include alkyd wood 1 finger, vinyl wood 1 finger
There are many old silicone resin paints, but if emphasis is placed on processability, they inevitably have drawbacks in other properties, and their use is currently limited.

Currently, when trying to obtain good workability with the most commonly used alkyd resin or acrylic resin paints,
The coating becomes considerably softer and lacks hardness. On the other hand, if an attempt is made to obtain a coating film having local hardness, it becomes impossible to obtain a coating film having sufficient additive properties. Generally used alkyd Wllj contains orthophthalic acid,
Dicarboxylic acid and alcohol components of sodium adipate include glycols such as ethylene glycol, phlopylene gelicol, and neopentyl glycol, as well as trimethylolpropane, pentaerythritol'h. To (T)
The polycarboxylic acid containing at least 207% of the total acid component is obtained by removing all polycarboxylic acids such as polyalcohol (trivalent or trivalent or trimeric) M or higher than 3fl]II.

However, if orthophthalic acid is the main raw material, 17, and 3
When polyols with higher functional properties or polycarboxylic acids are added to a certain level of hardness, they lack continuity and flexibility, resulting in a hard and brittle coating surface that is difficult to process. was difficult to form.

The present inventors have already applied alkyl etherified formaldehyde resin to various copolymerized polyesters in order to obtain coated steel sheets that have excellent processability, stain resistance, solvent resistance, and complaint resistance, and have daytime gloss. However, as we conducted further research into improving this, we found that by blending an alkyl etherified formaldehyde resin with a specific copolymerized polyester, we could not only further improve processability but also improve weather resistance.'' We have discovered two things and arrived at the present invention.

That is, the present invention uses isophthalic acid 80 to 3 as the acid component.
0 mole, 1j aliphatic dihydric sulfonic acid 2 with a disaster prime number of 4 to 12
0 to 45 mol of terephthalic acid, 0 to 25 mol of terephthalic acid, and 0 to 5 mol of trivalent or higher J- polycarboxylic acid, and 92 to 10 mol of neopentyl glycol as a polyol component.
07%, E, L: H trifunctional or higher functional polyol 0~
One finger of copolyester resin consisting of 87 molecules 95-70
This is a coating composition for painted steel sheets, characterized in that it contains 30 parts of alkyl ether and 30 parts of alkyl ether.

The polyester resin of the present invention has an acid component of 80% isophthalic acid.
-30 mol%, preferably 74-317 mol%, terephthalic acid 0-25 mol%. Desired -f, n-, i1 to 19 molar ratio, aliphatic dicarboxylic acid having 4 to 12 carbon atoms, 20 to 45 molar ratio, preferably 30 to 42 molar diameter, and trivalent or higher polycarboxylic acid O to 5 The polyol component consists of 92 to 100 moles of neopentyl glycol and 0 to 87 moles of trifunctional polyol, and the reduction accuracy is 0, 15 to 0.80. Desirably 0.22 to 0.6
There is ζ in the range of 0.

Aliphatic carbon having 4 to 12 carbon atoms used in the present invention) Li
Examples of the phonic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, etc. Trivalent or higher polycarboxylic acids include trimellitic acid,
Examples include trimesic acid and pyromellitic acid.

Examples of the trivalent or higher polyols include trimethylolethane, trimethylolpropane, chrycerin, and pentaerythritol.

The diol component of the present invention is neopentyl glycol, but other diol components can also be used in combination within a range that does not impair weather resistance, preferably within a range of 10 moles or less relative to the polyol component.

Further, hydroxycarboxylic acids such as 2-hydroxyethoxybenzoic acid can also be used in an amount of 10 moles or less per mole of total acids.

The acid components used in the polyester resin finger of the present invention are 80 to 30 moles of isophthalic acid, 20 to 45 moles of +1 aliphatic dicarboxylic acid having 4 to 12 carbon atoms, and O to 2 mol of terephthalic acid.
5 moles and trivalent or higher polycarphonic acids O to 5 moles. Isophthalic acid exceeds 80 mol%, carbon number is 4
If the amount of the aliphatic dicarboxylic acid of -12 is less than 20 mol φ, the resulting coating film will have poor flexibility and will not exhibit high dihydrity L2. Conversely, if isophthalic acid is less than 30 mol%, 1
If the amount of dicarboxylic acid exceeds 45 mol %, the resulting coating film will be too soft, easily scratched, and have poor weather resistance. -Also, if terephthalic acid exceeds 25 mol%, some crystalline particles will be formed, resulting in a cloudy solution after dissolving the polyester resin in a solvent, or a decrease in the gloss of the resulting coating film. .

Polyol component H 1 used in the polyester resin of the present invention Neopentyl glycol 92 to 100 mol%
, and 3Ii11j or more polyols 0-87.

0 to 5 mol% of trivalent or higher polycarboxylic acid (in acid component)
and/or 3 f11i100 polyol is used in an amount of 0 to 8 mol% (in the polyol component); however, in any case, if the upper limit is exceeded, the 1' coating loses its flexibility and bends. If 41 companies have poor flexibility and curvature, it is desirable that the sum of both is 10 mol% or more in the gold component. In addition, if the sum of the two is less than 1 molar proportion of all components, the relationship with the algyl etherified aminopolmaldehyde resin will be low, and the performance such as solvent resistance of the coating film will be affected. Since it tends to be low, the sum of both is preferably 1 to 10 molti out of all the components.

The copolymerized polyester of the present invention is produced by a conventional method for producing Hiburoshisha polyester, such as a transesterification method or a direct esterification method.

For example, methanol, ethanol,
Formaldehyde or paraformaldehyde that has been alkyl etherified with an argyl alcohol having 1 to 4 carbon atoms such as n-propatool, inpropatool, n-butanol, etc. Tourea, N,N-ethylene urea, dicyandiamide, 'aminotriazine, etc. Seven &
methoxylated methylol I
jf g , methoxylated methylol %, N-ethylene urea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, butoxylated methylol mesomemine, butoxylated methylol benzoguanamine, etc. Processability of 1 m is desired [7 Inoke is methoxylated methylol melamine, and 7 Iic is methoxylated methylol melamine, each of which can be used alone or in combination.

In the coating composition of the present invention, the ratio of the copolymerized polyester to the alkyl etherified formaldehyde is preferably 95-7:5-30 (heavy ratio). If the ratio of the copolymerized polyester exceeds 95 parts by weight, it is not preferable because the desired solvent resistance (itability) and coating film stability are insufficient. If the length is less than 7 degrees, the workability will be poor and it will be unskillful.

An amine of p-toluenesulfonic acid, phosphoric acid monoalkyl ester, or p-)toluenesulfonic acid may be added to the coating composition of the present invention as a historicizing catalyst. As for the use of tactile tactics, it is O to 5 Jusha Chi for 1 finger of No. 11 formaldehyde tree.

The coating composition of the present invention is used in part in the form of a solution in an organic solvent. Auto-organic solvents include Tatoeba, toluene, cylene, Tsurpetz 150, ethyl acetate, butyl acetate, and cellosolve.

It can be arbitrarily selected from butyl cellosolve, cellosolve acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohegisanone, isophorone, butanol, octatool, butyl calpitol, diethyl trivitol, tetrahydrofuran, etc. depending on its solubility and evaporation rate.

In many cases, high-speed painting and high-iM short-time baking are performed in the production of coated steel sheets, so two to three solvents with a boiling point of 100°C or higher are used to prevent the formation of pin-poles and other total film defects in the coating film. It is hopeless to mix and use more than one kind.

It is preferable to use polar solvents such as aliphatic hydrocarbons of 90 to 30%, polymerized ketones, ethers, etc. at a ratio of 10 to 70%.

It should be noted that even when the paint composition 0 Gozo J'1 itself of this study is applied to a steel plate and fired, it exhibits sufficient performance even when exposed to heat. be done'M
Go'iC? t1. Epoxy 141 as an agent, for example the commercially available Epicort 001,
#1004° #1.007 (manufactured by Shell Chemical Co.), Abuldite 6o97 (manufactured by Chipa Geigy), etc. are used.

The baking temperature of the coating composition of the present invention is determined by the size of the steel plate.

Jlf! It may be selected arbitrarily depending on the hk power of the baking/J" kiln, the t1 historicization property of the paint, etc. A kneading machine such as a roll kneading machine, a ball mill, or a Zollender is used for producing the paint composition. For painting, methods such as roller coating, roll coater, spray coating, and static coating are selected as appropriate.

The coating composition of the present invention may contain pigments such as titanium oxide, glass fiber, and silica depending on the purpose and use.

It is possible to add bulk additives such as wax. After the coating composition of the present invention is applied to a steel plate, it has excellent /Jl+ properties, and the coated surface has excellent solvent resistance and adhesion, a high degree of weather resistance, and high gloss and sharpness. have sex.

The present invention will be explained below using examples. In the examples, "part" simply indicates an overlapping part, and "chi" indicates an overlapping percentage. Each measurement item was measured according to the following method. 25CI1. and measured at 30°C.

(2) Tf, hardness) The coated surface of the steel plate was measured according to JIS K-5400 using a high-grade lead drawing specified in JIS S-6006.

(3) Light Sawa 600 reflectance was measured.

(4) Flexibility When a painted steel plate is bent 180 degrees, the cracks that occur at the bend are reduced to 1.
Judgment was made by observing with a 0x magnifying glass.

3T refers to the case where three pieces of the same board are held at the bending part, and OT refers to the case where the board is bent 180 degrees without being careful.

(5) Resistance to gauze A cork stopper was soaked with sweet gauze and the coated surface was rubbed, as indicated by the number of times until the bare surface came out.

(6) Weatherability: Expressed as gloss retention after 500 hours of irradiation using an accelerated weatherability tester QUV. Q tJ V irradiation conditions UV
One cycle was 8 hours at 60°C for 4 hours and 50°C for 4 hours, and 62.5 cycles were performed.

Example 1 116.4 parts of dimethyl terephthalate, 388.0 parts of dimethyl isophthalate, 513 parts of neopentyl glycol
．． 8 parts 1, 26.8 parts of trimethylolpropane, and 0,635 parts of zinc acetate, heated to 160°C to 22°C.
A Nisdell exchange reaction was carried out over a period of 4 hours.Next, 204.4 parts of adipic acid was added and heated at 200°C to 240°C for 2 hours to carry out an esterification reaction. Next, the pressure was reduced to 20 to 25 all't over a period of 30 minutes, and a polycondensation reaction was further carried out at 260°C for 60 minutes.

Obtained copolymerized polyester (A) ldNMR etc.+7)
As a result of compositional analysis, the acid component was found to have a molar ratio of terephthalic acid/isophthalic acid/adipic acid (15150/35), the glycol component to have a molar ratio of neopentyl glyco, and the polymer composition was shown in Tables 1-1 and 1-2. The following copolymerized polyesters (B) to (J) were synthesized. (J) Each cyclohegisanone/Tsurupets-
150 mixed solvent (weight ratio 50150).

The nonvolatile content was adjusted to 40 cm.

To 100 parts of the copolymerized polyester IJ finger (A) solution, 40 parts of titanium oxide, methyl etherified methylolmelamine (trade name: Sumimaru M-4O8, non-volatile content 80%, 10 parts of Sumitomo Chemical Co., Ltd., p-1 luene sulfone) Add 0.5 part of nmH (20 weight 37% solution of benzyl alcohol) and 0.2 part of Polyflow S (manufactured by Kyoeishashira M3sashi Chemical Industry Co., Ltd.), disperse the pigment for 2 hours using a glass pear type high-speed shaker, and then paint. A coating composition for steel plates was prepared.

Copolymerized polyester 11i & (A) to (B) to (J)
Alternatively, as an alkyl etherified aminoformalteeth al11, methyl ether melamine (trade name: Sumimaru M100, manufactured by Sumitomo Chemical Industries, Ltd.), butyl etherified melamine (trade name: Nisuper Beckamine J-820-60, Dainippon Ink Chemical Co., Ltd.) The coating compositions shown in Tables 2-1 and 2-2 were obtained in the same manner instead of the coating compositions shown in Tables 2-1 and 2-2.
G-3302) was coated on a test piece treated with a phosphoric acid curved solution to give an IIQ thickness of 18 to 22μ, and then
Baking was performed at 230°C for 2 minutes. The test results of the obtained coated steel sheets are shown in Tables 2-1 and 2-2.

Table 2-1 1) Product Name Sumimaru M40S Manufactured by Sumimaru Chemical Industry 2) Product Name Sumimaru M-100 Manufactured by Sumimaru Chemical Industry 3
) Product Name Super Beckamine J-820-60 Manufactured by Dainippon Ink and Chemicals No. 2-2 Comparison Polyester Lull 1) Product Name Sumimaru M40S Manufactured by Sumimaru Chemical Industry 2) Product Name Sumimaru M-100 Manufactured by Sumimaru Chemical Industry 3 ) Product Name: Super Beckamine J-820-60 Manufactured by Dainippon Ink & Chemicals As is clear from Tables 2-1 and 2-2, the coating composition of the present invention has surface properties ( / Jll workability)
It has excellent weather resistance as well as excellent weather resistance.

Patent applicant: Toyobo Co., Ltd.

Claims (1)

[Claims] As acid components, 80 to 30 moles of isophthalic acid, 20 to 45 moles of aliphatic dicarboxylic acid having 4 to 12 carbon atoms, 0 to 25 moles of terephthalic acid, and trivalent or higher carboxylic acid. Polyether tree consisting of 0 to 5 mol% and 0 to 8 mol% of neopentyl glycol as a polyol component; 95 to 70 mol%
1. A coating composition for painted steel sheets, comprising 5 to 30 parts of an alkyl etherified amino formaldehyde resin.