Polyester paint of high solid for coiled material and lithographed sheet

[0024] Example 2

[0025] 1. See Table 2 for the formula

[0026]

[0027] 2. Preparation process

[0028] Dibasic alcohols, dibasic acids, polybasic acids and polyhydric alcohols and 50 parts of reflux xylenes in the amount shown in Table 2 were put into the reaction flask identical to Example 1 at one time, slowly warming up to 120°C, and 1.63 parts of dibasic Dibutyltin laurate and 1.2 parts of triphenyl phosphite, continue to heat up until the material starts to reflux, then heat up at a rate of 10°C per hour, during which the gas phase temperature is controlled at 90±5°C, and the reaction temperature is 230±5°C. When the acid value reaches 0.8mgKOH/g, vacuumize for half an hour to remove residual small molecular substances and solvent molecules and measure reaction dehydration (159 parts of theoretical water output). The temperature dropped to about 150°C, and finally 370 parts of mixed thinner (Solvesso 180/ethylene glycol ether acetate/DBE=3/2/1, weight ratio) were added to obtain a polyester resin with a theoretical solid content of 80%.

[0029] 3. Resin properties

[0030] With the polyester resin that above-mentioned formula and preparation process make, its acid value is 0.8mgKOH/g; Hydroxyl value is 210mgKOH/g; Type rotational viscometer (measured at 23°C); the number average molecular weight (Mn) of the resin was 1530 (measured by gel permeation chromatography).

[0031] Example 3

[0032] 1. See Table 3 for the formula

[0033]

[0034] 2. Preparation process

[0035]Put the dibasic alcohols, dibasic acids and polyols and 50 parts of refluxed xylene in the same reaction flask as in Example 1 at one time as shown in the formula in Table 3, slowly raise the temperature to 120 ° C, and put in 1.71 parts of dilauric acid di Butyltin and 1.28 parts of triphenyl phosphite, continue to heat up until the material starts to reflux, then heat up at a rate of 10°C per hour, during which the gas phase temperature is controlled at 90±5°C, and the reaction temperature is 230±5°C and heat preservation is started until the acid value reaches When the concentration is 1.2 mgKOH/g, vacuumize for half an hour to remove residual small molecular substances and solvent molecules and perform metered reaction dehydration (207 parts of theoretically produced water). The temperature was lowered to about 150° C., and finally 376 parts of mixed thinner (Solvesso 150/isophorone=6/4, weight ratio) were mixed in to obtain a polyester resin with a theoretical solid content of 80%.

[0036] 3. Resin properties

[0037] With the polyester resin that above-mentioned formula and preparation process make, its acid value is 1.2mgKOH/g; Hydroxyl value is 160mgKOH/g; Type rotational viscometer (measured at 23°C); the number average molecular weight (Mn) of the resin was 1850 (measured by gel permeation chromatography).

[0038] The raw materials used in the formula of examples 1~3 are commercially available industrial products. The proportions of various acids and alcohols are shown in Table 4

[0039] project

[0040] (2) High solid polyester coatings for coils

[0041] Example 4 sea blue

[0042] 1. See Table 5 for the formula

[0043] raw material name

[0044] ②Kronos 2310 is the grade of chloride-process rutile titanium dioxide produced by Kronos Corporation of the United States;

[0045] ③BYK-310 is the grade of high temperature resistant silicone product produced by German BYK company;

[0046] ④Cymel 303 is the product brand of fully methyl etherified melamine resin produced by Cytec Corporation of the United States;

[0047] ⑤EFKA 4047 is the product brand of Efka Company in the Netherlands;

[0048] ⑥Nacure 2500 is the product brand of blocked p-toluenesulfonic acid produced by Kings Corporation of the United States.

[0049] 2. Coating preparation process

[0050] Get a part (75 parts) in the polyester resin of Example 1 according to the formula, add 50 parts of titanium dioxide (Kronos 2310), 10 parts of phthalocyanine blue (15: 2), 18 parts of dispersant (EFKA 4047) and 35 parts of mixing solvent (Solvesso 150/propylene glycol butyl ether/isophorone=3/1/1), and then the mixture was ground into a pigment paste with a fineness of ≤15 μm by a sand mill.

[0051] Add the remaining (75 parts) polyester resin of embodiment 1, 30.6 parts of melamine resin (Cymel 303), 6.0 parts of catalyst (Nacure 2500) and 1.7 parts of leveling agent (BYK-310) successively in the above-mentioned pigment slurry, and then use Dilute the mixed solvent (Solvesso 150/propylene glycol butyl ether/isophorone=3/1/1) to a coating solid content of 75±2% (weight), and apply it at 23°C to -4 cups with a viscosity of 100±10 seconds for later use.

[0052] 3. Coating construction and performance

[0053] Adopt the two-coating and two-baking roller coating construction process on the passivated galvanized plate, after coating the matching epoxy primer, use the wire rod with a wet film thickness of 20 μm to scrape the sea blue paint in the above example 4 as the topcoat , baked in an oven at 375°C for 40 seconds, the peak temperature (PMT) of the metal plate during curing is 216°C, and the total thickness of the dry film is 20±2μm. The coating properties are as follows:

[0054] Pencil hardness: 2H;

[0055] Impact (cm): 100;

[0056] Cross-cut adhesion (level): 0;

[0057] T bend: 3T;

[0058] Resistance to MEK performance (round trip, times): >100.

[0059] Example 5 White

[0060] 1. See Table 6 for the formula

[0061] raw material name

[0062] ②Auxiliary film-forming substances accounted for 12.9% of the total weight of film-forming substances;

[0063] ③ LTW is the product brand of adhesion promoting resin produced by German Degussa Hls company;

[0064] ④R717 is the product brand of partially methylated melamine resin produced by Solutia;

[0065] ⑤BYK-358 is the product brand of acrylic leveling agent produced by BYK in Germany;

[0066] ⑥EFKA 4010 is the product brand of Efka Company in the Netherlands.

[0067] 2. Coating preparation process

[0068] Except for the polyester resin of Example 2 used as a film former, 60 parts are dispersed and ground together with pigments and dispersants to a specified fineness, and then the remaining film formers (24.4 parts) and auxiliary film formers are added, and the rest are as in the example 4 Preparation process Prepare the paint for later use.

[0069] 3. Coating construction and performance

[0070] Except that the white paint of above-mentioned example 5 is used as top coat, construction method is identical with example 4, and gained film performance is as follows:

[0071] Pencil hardness: 2H;

[0072] Impact (cm): 100;

[0073] Cross-cut adhesion (level): 0;

[0074] T bend: 2T~3T;

[0075] Resistance to MEK performance (round trip, times): >100.

[0076] (3) High solid polyester coating for iron printing

[0077] Example 6 White-1

[0078] 1. See Table 7 for the formula

[0079] raw material name

[0080] ②Auxiliary film-forming substances accounted for 7.9% of the total weight of film-forming substances;

[0081] ③Baxenden BI-7982 is the product brand of blocked hexamethylene diisocyanate trimer produced by British Baxenden Company.

[0082] 2. Coating preparation process

[0083] Get a part (62.5 parts) in the polyester resin of embodiment 1 by formula, add 100 parts of titanium dioxide (Kronos 2310), 3 parts of dispersants (EFKA 4010) and 33 parts of mixed solvents (Solvesso 150/propylene glycol butyl ether/ isophorone=3/1/1), and then grind the mixture into a pigment slurry with a fineness≤10 μm through a sand mill.

[0084] Add the embodiment 1 polyester resin of remainder (27.5 parts), 7.8 parts of auxiliary film former epoxy resins (domestic 6101), 16.3 parts of melamine resins (Cymel303), 11.4 parts of blocked isocyanate curing agents ( Baxenden BI-7982), 3.6 parts of catalyst (Nacure 2500), 0.02 parts of catalyst (dibutyltin dilaurate) and 1.6 parts of leveling agent (BYK-310), and then use mixed solvent (Solvesso 150/propylene glycol butyl ether/isophore Alone=3/1/1) is diluted to 75 ± 2% (weight) of coating solids content, and 23 ℃ is coated with -4 cups of viscosity 100 ± 10 seconds for subsequent use.

[0085] 3. Coating construction and performance

[0086] Use the one-coat-one-bake roller coating construction process on the degreased tin plate, use a wire rod with a wet film thickness of 20 μm to directly scrape the above-mentioned white-1 paint of Example 6 as the top coat, and bake it in an oven at 180 ° C for 10 minutes After curing, the dry film thickness is 15±2μm, and its coating properties are as follows:

[0087] Pencil hardness: H;

[0088] 60° gloss: 92;

[0089] Cross-cut adhesion (level): 0;

[0090] T bend: 1T;

[0091] MEK resistance performance (round trip, times): >100;

[0092] Retort performance (15min/120℃): no loss of gloss, no foaming.

[0093] Example 7 White-2

[0094] 1. See Table 8 for the formula

[0095] raw material name

[0096] ② BL-3175 is the product brand of blocked hexamethylene diisocyanate biuret produced by Bayer AG in Germany.

[0097] 2. Coating preparation process

[0098] Except that all (56 parts) of the polyester resin of Example 3 used as film formers are dispersed and ground together with pigments and dispersants, all the other are prepared by the preparation process of Example 6 for subsequent use.

[0099] 3. Coating construction and performance

[0100] Except making finish coat with above-mentioned example 7 white-2 coatings, construction method is identical with example 6, and gained coating performance is as follows:

[0101] Pencil hardness: H;

[0102] 60° gloss: 96;

[0103] Cross-cut adhesion (level): 0;

[0104] T bend: 0T;

[0105] MEK resistance performance (round trip, times): >100;

[0106] Retort performance (15min/120℃): no loss of gloss, no foaming.

[0107] The following methods are used when inspecting the above-mentioned coating film properties:

[0108] (1) Pencil hardness: GB/T6739-1996

[0109] (2) Shock: GB/T1732-93

[0110] (3) Cross-cut adhesion: GB/T9286-88

[0111] (4) Gloss: GB/T9754-88

[0112] (5) T-shaped bending flexibility (referred to as T-bend): clamp a 3-inch wide coated plate into a T-bend instrument and bend it to 90°, and then use a flattener to bend and flatten the coated plate to 180°, that is It is 0T; follow the same steps, the thickness of one plate between the plates is 1T, the thickness of two plates is 2T, and so on. Use Scath 610 adhesive tape to stick the curved coated board section along the curved direction, remove the adhesive tape at a constant speed, and pass if the paint film does not fall off. The smaller the value of the T bend, the better, and 0T is the best.

[0113] (6) Methyl ethyl ketone resistance performance (MEK resistance performance): Use eight layers of gauze to dip the index finger in methyl ethyl ketone solvent, and immediately move back and forth on the coated board with appropriate pressure to wipe. The stroke is at least 20cm, and the pressure is about 2 kg. Wipe The speed is about 100 round trips per minute. Write down the number of times of wiping (one forward, one time backward is counted as one round trip), until the coating film is damaged or the predetermined number of round trips is reached.

[0114] (7) Retort performance: Cook the coated board in boiling water at 120°C for 15 minutes, and observe whether the coating film loses gloss, fades, and bubbles.

[0115] As can be known from the above test data, the coatings of Examples 4-7 can be constructed with high solids (75 ± 2%) and low viscosity (100 ± 10 seconds) and the resulting coating film properties have maintained the level of similar common solvent-based polyester coatings. From the T-bend value for evaluating the flexibility of the coating film and the pencil hardness value for evaluating the hardness of the coating film, it can be seen that the flexibility/hardness balance performance of the above-mentioned coating films also maintains the level of ordinary solvent-based polyester coatings.

[0116] The paint of the invention can be widely used in the pre-coating of metal materials such as cold/hot-rolled steel sheets, electric/hot-dip galvanized steel sheets, tin-plated sheets, and aluminum sheets. Because the VOC content of the paint of the invention is far lower than that of common solvent-based polyester paints, the harm to the environment and human body during the paint production and construction process is greatly reduced.