What effect does IPA content have on carboxyl and viscosity in polyester bottle chip production?

The latest artificial accelerated aging silicon test

Key words: silicone modified polyester; Durable film smoothness; QUV-B aging machine, artificial accelerated aging silicon test

brief introduction

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Pre-coated coil coatings are economical and environmentally friendly, and meet the needs of today's social and economic development, so they are widely used. With the continuous progress of technology, its application has been extended to home appliances, decoration, furniture and other fields. However, its main application is in the construction industry, and a large number of outer films need a lasting and beautiful decoration and protection performance. Silicone modified polyester has excellent pollution resistance, weather resistance, good adhesion and fast curing speed, which meets the requirements of pre-coated coil coatings and is very suitable for internal coating of wear-resistant films. The coating formed by the prepared coating has excellent self-cleaning, gloss and color retention, pulverization resistance, toughness and wear resistance. P> polysiloxane bonded bridge modified polyester resin can be divided into two types: Si-C and Silicone. The former is made of siloxane (oxy) alkyl containing carboxyl group, and the reaction with polyol is not industrialized because of expensive raw materials and complicated process. The latter is prepared by the condensation reaction of hydroxyl-containing polyester, silicon (oxygen) alkoxy or hydroxyl-containing silicon and silicon (oxygen) alkoxy alkoxy. Easily available raw materials, simple production process and wide application. /& gt； /& gt； Considering the feasibility and cost of industrialization, polysiloxane modified polyester resin was developed by the latter and prepared by siloxane condensation reaction containing hydroxyl and alkoxy groups. Silicone modification greatly improves the durability of the coating. Reaction: ≡ SiOR+HOC≡→≡ SiOC≡+ ROH.

Experimental part

1. 1 raw materials

Isophthalic acid (IPA): >; 99.5%, industrial, adipic acid (ADA): > 99.5% and industrial cyclohexane dicarboxylic acid (CHDA): imported neopentyl glycol (NPG): > 99%, industrial, trimethylolpropane (TMP): industrial, dibutyltin dilaurate, chemical purity: silicone intermediate: Dow Corning xylene: industrial; HY-C-02 thinner: coil coating thinner produced by Jiangsu Hongye Coating Company, and R-706 titanium dioxide: DuPont rutile; Titanium Dioxide Lonman996: Dragon Python Rutile Titanium Dioxide TS-6200: Dupont, USA, Rutile Tinuvin 928 Tinuvin 5060 Tinuvin123: Ultraviolet Absorber, Ciba Specialty Chemicals Company, BYK-450: Acid Catalyst, Bicycle Company; EFKA-3777: leveling agent, byk-efkahy-c-1kloc-0/light yellow primer: polyurethane primer produced by Jiangsu hongye coating company.

1.2 experimental program

1.2. 1 Synthesis of resin

In a flask equipped with stirrer, thermometer, reflux condenser and water separator, IPA2 12.4g, CHDA 220. 1g, Ada3 1g, NPG277.0g, TMP58.4g, xylene 80g and dibutyltin dilaurate 0.4g were added in turn, and slowly heated to about 650. Slowly raise the temperature to 140℃, or reflux dehydration, slowly raise the temperature to 200℃ for about 3 hours, keep the temperature for 1 hour, then raise the temperature to 220℃ for about 1 hour, keep the temperature for about 1 hour, until the final reaction acid value is 3 mg KOH/g, and cool to/after the reaction is completed. Add 609.3g HY-C-02 diluent, then add 2 13.9g silicone intermediate, 0.9g dibutyltin dilaurate and tin, and slowly raise the temperature to 170℃, or at the start-up stage of the reaction, separate methanol and reflux, continue to heat the reaction for 12h, and raise the temperature to about/kloc-0. After cooling for 2 minutes, the siloxane modified polyester resin with solid content of 60% was obtained.

1.2.2 coating

Mix 100g of silicon-modified polyester resin, 180G of dilute titanium dioxide in a clean beaker, and an appropriate amount of HY-C-02 with a high-speed dispersion small sander, add an appropriate amount of zirconium beads to grind a scraper with a dispersion fineness less than or equal to 15μ m, and then discharge it to the laboratory for dispersion and pasting. The ratio of pigment to binder (P/B) is 75/25, and the solid content is 65%.

37.9g of silicone modified polyester resin, 9.9g of cross-linking agent amino resin, BYK-450.19g, EFKA-3777.5438+02g and a proper amount of HY-C-02 thin material were added into100g paste, and the white topcoat was dispersed and stirred at high speed.

1.2.3 performance test

1.2.3. 1 process conditions

10cm x 6cm Yellowstone 0.4mm galvanized sheet is washed with water, taken out and dried with chromium solution, 150℃ baked 1min, and leveled with hy-c-10/light yellow primer and 10 # scraper. Test the performance of the composite membrane.

Furnace temperature: 330°C, baking time: 2930; Plate temperature: 224232℃

Dry film thickness: primer 56 microns, topcoat 12 to 13 microns.

Model preparation and performance test, including: T-shape, film thickness, pencil hardness, MEK wiping resistance (back-and-forth test 1.2.3.2) and aging resistance.

2 Results and discussion

2. 1 test results

2. 1. 1 mechanical performance test

The mechanical properties are shown in the above table 1.

Table 1 Results of self-made silicone modified polyester and comparison samples with different mechanical properties.

According to the data in table 1, there is no significant difference in mechanical properties between the self-made silicone modified polyester and the comparative polyester.

2. 1.2 aging performance test results

(1) comparison of aging test results of different types of resin QUV-B

Compared with various polyester resins for white paint system boards, the self-made silicone modified white paint has different aging properties (QUV-B). The results are as follows.

Test conditions: Type I has no condensed water at 60°C for 4H; Mode ⅱ 50 C plus 4 hours of condensation, I plus II is a cycle.

The light loss rate of different types of coatings changes with time, as shown in figure 1.

In figure 1, the fluorocarbon resin Wuxi FEVE is the same chemical resin and durable polyester, and the durable polyester resin HDPE is being developed by Changzhou Institute of Coatings and Chemical Industry. From the results in figure 1, it can be found that the QUV-B test result of silicone modified polyester white paint can reach 400H without losing light, and the light loss rate of 600H is 20%. The aging speed of paint film is higher than that of white durable polyester paint and ordinary polyester white paint, but slightly lower than that of fluororesin white paint.

Figure 1 trend of high gloss loss rate of resin system

(2) The artificial accelerated aging test results of silicone modified polyester resin (solar aging tester).

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The preparation of white template paint accelerated the aging test, which was carried out according to the manual test procedure of National Paint Testing Center. The test conditions are: temperature (65 2) C and humidity 60% 80%. The test results are shown in Figure 2.

Fig. 2 artificial accelerated aging test results of silicon modified polyester resin

In addition, the artificial accelerated aging test shows that the δ E value of the high gloss coating is 1.9 after 3000H, and there is no pulverization phenomenon. After testing for 2400H in dark light, the δ E value of the coating is 1.7, which is one of the powders.

Based on the above results, the artificial accelerated aging test of silicon modified resin can reach 2000 hours (1 tarnish, discoloration and pulverization).

2.2 Infrared Spectrum Analysis of silicone Modified Polyester Resin

The infrared spectrum of self-made polysiloxane modified polyester resin is shown in Figure 3.

Infrared spectrum (IR) of the siloxane intermediate of fig. 3

Fig. 3 shows the absorption peaks of Si-OCH 3 at 2840.6 cm-1, 192.9 cm-1 and 1079.8 cm. These absorption peaks disappeared in the infrared absorption spectrum of silicone modified polyester, indicating that the reaction between polyester and polysiloxane intermediate has been completed.

Fig. 4 infrared spectrum of polyester resin

Infrared spectrum of silicone modified polyester.

2.3 Aging Performance of Titanium Dioxide

> Three different types of rutile titanium dioxide were tested, and the influence of aging property (QUV-B) was investigated. In the experiment, the experimental conditions of DuPont TS-6200 and Dragon Python 996 titanium dioxide are the same except titanium dioxide. The test results are shown in Figure 6.

Fig. 6 Aging performance of titanium dioxide

In Figure 6, it can be found that the aging test results of rutile titanium dioxide from different manufacturers have little effect.

2.4 Aging performance of ultraviolet absorber

The self-made silicone modified resin and R-706 titanium dioxide were observed, and the aging properties of UV absorber coating (QUV-B) with different dosage and types were prepared. The result is shown in Figure 7.

Fig. 7 Aging performance of ultraviolet absorber

Fig. 7 is a blank control, that is, a white paint prepared by adding 2% (based on the total solid resin content, the same below) of 928 123 and 1%, and adding 1.5% and 3% of 5060 to 5060 respectively.

From the above results, it can be found that the aging resistance of the surface coating containing ultraviolet absorber has been improved.

2.5 Extinction aging performance

Self-made silicone modified resin and R-706 titanium dioxide white paint were prepared, and the extinction of silica was different. The aging performance (QUV-B) of the light powder coating was observed, and the result is shown in fig. 8.

Fig. 8 Effect of Extinction Aging Performance

In Figure 8, the light loss rate of the high gloss coating for 600H is about 65438 09%; The light loss rate of the optical coating for 600H is about 265438 0%; The light loss rate of low gloss coatings for 600 hours is about 28%.

These results show that the aging resistance of the coating decreases with the increase of extinction and extinction.

Concluding remarks

The mechanical properties of a silicone modified polyester coating prepared by precoating coil coating can meet the requirements of coil processing. The ultraviolet accelerated aging test (QUV-B) can basically lose light for 400H hours, and the artificial accelerated aging test can reach 2000 hours, and the loss of light is discolored.