CN103937388B - Nano combined gel coat of weather resistant and preparation method thereof - Google Patents

Abstract

The invention discloses a weather-resistant nano-composite gel coat, which consists of the following ingredients in parts by weight: 100 parts of unsaturated polyester resin, 10-30 parts of styrene, 10-25 parts of modified nano-ZnO, 5 parts of talc powder -8 parts, 3-5 parts of titanium dioxide, 1-3 parts of thixotropic agent, 0.1-0.2 parts of thixotropic stabilizer, 0.4-1 part of surface additive, 0-10 parts of color paste, and 0.1-0.4 part of accelerator. The present invention also simultaneously provides a preparation method for the above-mentioned weather-resistant nano-composite gel coat, comprising the following steps: 1), successively adding talcum powder, titanium dioxide, thixotropic stabilizer and thixotropic agent to the unsaturated polyester resin; 2) 1. Add modified nano-ZnO to styrene, and add it to the result of step 1) after high-speed dispersion; 3), add color paste, surface additives and accelerators to the result of step 2). The weather-resistant nano-composite gel coat is mainly used on the surface of FRP cooling tower.

Description

Weather-resistant nanocomposite gel coat and preparation method thereof

technical field

The invention relates to a weather-resistant nano-composite gel coat and a preparation method thereof. The weather-resistant nano-composite gel coat is mainly used on the surface of glass fiber reinforced plastics of cooling towers.

Background technique

Cooling towers are commonly used equipment in industrial circulating water, and are often used in steel factories, printing and dyeing factories, pharmaceutical factories, nuclear power plants, air conditioners, cold storage, chemical fiber, petroleum and other fields. At present, the commonly used cooling tower body is generally made of FRP. In order to improve the appearance quality of FRP and protect the material of FRP structural layer from corrosion by external media, a layer of gel coat is often coated on the surface of FRP. Gel coat is a special application of unsaturated polyester resin, its main component is polymer material, so when it is often exposed to various environments such as sunlight, wind and rain, high temperature, severe cold, etc. Over time, its weather resistance will decrease, resulting in chalking, discoloration and other phenomena. In order to improve the weather resistance of the gel coat, one method is to use unsaturated polyester resins with better weather resistance, and the other method is to optimize the fillers in the gel coat, because fillers can improve the mechanical strength, wear resistance, and Water resistance and weather resistance (Cao Xin, Research on Weather-resistant Flame Retardant Gel Coat Resin, Fiber Composite Materials, 2005, 1:10-11; Zhang Huijuan, Effects of Gel Coat Components on Gel Coat Aging Performance, East China University of Science and Technology, 2011 Year, Master of Engineering Thesis).

Nano-ZnO is a new type of multifunctional oxide, which has the characteristics of surface effect, volume effect, quantum size effect and macroscopic tunnel effect, as well as high transparency and high dispersion that macroscopic objects do not have. In addition, nano-ZnO also has good ultraviolet shielding performance, and its ultraviolet shielding rate is as high as 98%. However, there are still two problems when using nano-ZnO as a filler:

1) Nano-ZnO has high surface energy, is easy to agglomerate, and has poor compatibility with the matrix resin. In order to solve this problem, coupling agents or surfactants are often used to modify the surface of nano-ZnO, but this modification method A large amount of organic solvents are usually used, such as ethanol, toluene, etc., which pollute the environment, are toxic to the human body, and increase the cost of recovery or destruction (Shi Zhen et al., Surface Modification Research of Nano-ZnO, Shanghai Paint, 2008,46 (5) 1-3; Wu Wenming, Pan Lei, etc., Surface modification of nano-ZnO and preparation of ZnO/UPR composite materials, Thermosetting Resins, 2009, 24(5): 44).

2) At present, the amount of modified nanoparticles added to the matrix resin is not large, otherwise it will have an opposite effect on the performance of the resin, such as reducing the mechanical properties and increasing the viscosity of the coating, resulting in failure to form, etc. (Wu Wenming, Pan Lei et al. , Surface modification of nano-ZnO and preparation of ZnO/UPR composite material, Thermosetting Resins, 2009, 24(5): 44; Wang Haifeng, Xu Yi, etc., Preparation and properties of nano-Al ₂ O ₃ filled PTFE composite material, Plastic Industry, 2012,40(6):88; BauerF, et al.Preparationofsctrachandabrasionresistantpolymericnanocompositesbymonoergraftingontonanoparticles,effectoffillerpartilcesandgraftingagents,Macromol.Mater.Eng.2002,287,546-552.). Such problems will also appear in the gel coat modified by nano-ZnO, so the addition of nano-ZnO in the gel coat should not be too much, otherwise it will cause the viscosity of the gel coat to increase (thickening effect), but this is also harmful to the gel coat. The weather resistance of the clothing cannot be significantly enhanced.

Contents of the invention

The technical problem to be solved by the present invention is to provide a weather-resistant nano-composite gel coat and a preparation method thereof; the weather-resistant nano-composite gel coat is mainly used on the surface of glass fiber reinforced plastics of cooling towers.

In order to solve the above technical problems, the present invention provides a weather-resistant nano-composite gel coat, which consists of the following components by weight: 100 parts of unsaturated polyester resin, 10-30 parts of styrene, 10-25 parts of modified nano-ZnO , 5-8 parts of talcum powder, 3-5 parts of titanium dioxide, 1-3 parts of thixotropic agent, 0.1-0.2 parts of thixotropic stabilizer, 0.4-1 part of surface additive, 0-10 parts of color paste, and 0.1 part of accelerator -0.4 parts.

As an improvement of the weather-resistant nano-composite gel coat of the present invention: the preparation method of the modified nano-ZnO is:

Add 1 part of nano-ZnO with a particle size of 10-60nm to 1.5-2.5 parts (preferably 2 parts) of deionized water, stir at high speed for 10-30 minutes, then add 0.2-0.5 parts of modifier, and then adjust The pH is 3-5 (for example, 4), then heated up to 50-70°C, kept warm (50-70°C), stirred and reacted for 1-3 hours, filtered, and the obtained filter cake was vacuum-dried to constant weight at room temperature; Sexualized nano-ZnO;

The modifying agent is γ-methacryloxypropyltrimethoxysilane or vinyltriethoxysilane;

The above-mentioned parts are parts by weight.

Remarks: The adjustment of pH is carried out in a conventional manner, for example, 10% (by weight) HCl solution can be used for adjustment.

γ-Methacryloxypropyltrimethoxysilane is γ-(methacryloxy)propyltrimethoxysilane.

As a further improvement of the weather-resistant nano-composite gel coat of the present invention:

Described unsaturated polyester resin is ortho-phenylene-neopentyl glycol type unsaturated polyester resin, m-phenylene-neopentyl glycol type unsaturated polyester resin;

The thixotropic agent is gas phase SiO ₂ , with a specific surface area of 150-380m ² /g;

The thixotropic stabilizer is the PR600 type thixotropic stabilizer produced by Klein (Clariant) Company;

Surface additives are any three or four of BYK-A515, BYK-A555, BYK-S706 and JS-V966;

Colorants are azo pigments, color lakes, copper phthalocyanines, condensed rings and organic macromolecular pigments;

The accelerator is cobalt isooctanoate.

The present invention also simultaneously provides a preparation method for the weather-resistant nano-composite gel coat, comprising the following steps:

1) Put the unsaturated polyester resin into the dispersing kettle first, add talcum powder, titanium dioxide, thixotropic stabilizer and thixotropic agent successively under stirring, and disperse evenly;

2), adding modified nano-ZnO to styrene, and adding it to the mixture formed in step 1) after high-speed dispersion; uniformly mixing;

3) Add color paste, surface additives and accelerators to the result of step 2), and stir evenly to obtain a weather-resistant nano-composite gel coat.

In the present invention, room temperature refers to 15-25° C.; high-speed stirring is at a speed of 1000-2000 rpm; other stirring is at a speed of 500-800 rpm.

In view of the technical defects in the above-mentioned prior art, the present invention is to develop a weather-resistant nano-composite gel coat, which uses modified nano-ZnO as a filler to modify the gel coat. The preparation method of the modified nano-ZnO of the present invention (that is, the method for surface-modifying nano-ZnO) uses water as a solvent, has no pollution, and has little harm to the human body. As a coupling agent, it can undergo copolymerization reaction with unsaturated polyester resin, so it can enhance the bonding force between the filler and the matrix, and can reduce the damage of nano-ZnO to the mechanical properties of the gel coat. In addition, because the above-mentioned modification method set by the present invention can modify nano-ZnO very well, so its addition ratio in the gel coat is relatively high, and will not increase the viscosity of the gel coat, so it can significantly improve the viscosity of the gel coat on the one hand. The weather resistance of the gel coat, on the other hand, can also enhance the wear resistance and hardness of the gel coat, thereby reducing the addition of other hard fillers.

In summary, the present invention aims at the present situation that the gel coat on the FRP surface of the existing cooling tower has poor weather resistance, is easy to pulverize, and is easy to change color, and adds modified nano ZnO with good ultraviolet shielding function to the gel coat. , A weather-resistant nanocomposite gel coat was prepared.

The weather-resistant nano-composite gel coat prepared by the present invention adopts the internationally accepted accelerated artificial aging method and has been evaluated experimentally with reference to the US ASTM-G154 standard practice for using fluorescent equipment for ultraviolet rays of non-metallic materials. The artificial accelerated aging time is 1000 hours, and then used An automatic colorimeter (SC-80C, Beijing Kangguang Optical Instrument Co., Ltd.) was used to characterize the changes in chromaticity (△E) and yellowness (△Yid) of the coating before and after aging, and observed whether the coating was powdered with the naked eye. Experimental results show that after 1000 hours of artificial accelerated aging of the weather-resistant nano-composite gel coat of the present invention, its ΔE≤1.5, ΔYid≤1.5, and the surface of the coating has no pulverization.

detailed description

Embodiment 1,

1), surface modification of nano-ZnO (that is, the preparation method of modified nano-ZnO):

Weigh 100g of nano-ZnO (particle size 20nm) and add it to 200g of deionized water, stir at high speed for 10 minutes, add 20g of γ-methacryloxypropyltrimethoxysilane, and use 10% (weight ratio) HCl to adjust The pH of the system was 4, then the temperature was raised to 50°C, and the temperature was kept stirring for 3 hours, filtered, and the resulting filter cake was vacuum-dried to constant weight at room temperature; the modified nano-ZnO was obtained.

2) Preparation of weather-resistant nanocomposite gel coat

(1), add 100 parts of o-phthalic-neopentyl glycol type unsaturated polyester resin into the dispersion kettle, add 8 parts of talcum powder, 5 parts of titanium dioxide under stirring, thixotropic agent-gas phase SiO ₂ (specific surface area 150m ² /g) 3 parts, thixotropic stabilizer---PR6000.2 parts; stir for 30 minutes; thus achieve uniform dispersion.

(2), 10 parts of nano ZnO after modification is joined in 10 parts of styrene, after high-speed dispersion 30 minutes, join in the mixture that step (1) forms, stir evenly 0.5 hour; Thereby realize uniform mixing;

(3) Add 0 part of color paste and 0.5 part of surface additive to the mixture formed in step (2) (obtained by mixing BYK-A515, BYK-A555 and BYK-S706 in a weight ratio of 1:1:1) And accelerator --- 0.1 part of cobalt isooctanoate, after uniform stirring for 0.5 hours, a weather-resistant nano-composite gel coat is obtained.

Comparative example 1-1,

Change "add 20g of γ-methacryloxypropyltrimethoxysilane" in step 1) of Example 1 to "add 15g of γ-methacryloxypropyltrimethoxysilane", Others are with embodiment 1.

Comparative example 1-2,

Change "add 20g γ-methacryloxypropyl trimethoxysilane" in step 1) of Example 1 to "add 60g γ-methacryloxypropyltrimethoxysilane", and the others are the same as in the example 1.

Comparative example 1-3,

Change "add 20g of γ-methacryloxypropyltrimethoxysilane" in step 1) of Example 1 to "add 20g of 3-aminopropyltriethoxysilane", and the others are the same as in Example 1.

Comparative example 1-4,

In Example 1, "add 20 g of γ-methacryloxypropyl trimethoxysilane" is changed to "add 20 g of γ-glycidyl etheroxypropyl trimethoxysilane", and the others are the same as in Example 1.

Comparative example 1-5,

The reaction in step 1) of Example 1 was changed from "stirring reaction at 50°C for 3 hours" to "stirring reaction at 40°C for 4 hours"; others were the same as in Example 1.

Comparative example 1-6,

Change the reaction in step 1) of Example 1 from "stirring at 50°C for 3 hours" to "stirring at 80°C for 3 hours"; others are the same as in Example 1.

Comparative example 1-7,

Change the consumption of nanometer ZnO after the modification in embodiment 1 step 2) from 10 parts to 8 parts; Others are the same as embodiment 1.

After the nanocomposite gel coats prepared in Example 1 and Comparative Examples 1-1 to 1-7 were cured to form a film, they were artificially aged for 1000 hours, and their properties were shown in Table 1 (the detection method was as described above).

Table 1

ΔE △Yid Whether there is chalking Example 1 1.5 1.5 none Comparative example 1-1 1.7 2.0 Have Comparative example 1-2 1.8 1.9 none Comparative example 1-3 2.8 2.9 Have Comparative example 1-4 2.5 2.6 Have Comparative example 1-5 2.1 2.0 none Comparative example 1-6 2.0 2.2 Have Comparative example 1-7 1.6 2.0 none

Embodiment 2,

1) Surface modification of nano ZnO

Weigh 100g of nano-ZnO (particle size 40nm) and add it to 200g of deionized water, stir at high speed for 20 minutes, add 50g of γ-methacryloxypropyl trimethoxysilane, and use 10% (weight ratio) HCl to adjust The pH of the system was 4, then the temperature was raised to 70°C, and the temperature was kept stirring for 1 hour, filtered, and the resulting filter cake was vacuum-dried to constant weight at room temperature; the modified nano-ZnO was obtained.

2) Preparation of weather-resistant nanocomposite gel coat

(1), add 100 parts of m-benzene-neopentyl glycol type unsaturated polyester resin in the dispersion kettle, add 6 parts of talcum powder under stirring, 4 parts of titanium dioxide, thixotropic agent ---gas phase SiO ₂ (specific surface area 380m ² /g) 2 parts, thixotropic stabilizer----PR6000.1 part; stir for 30 minutes to achieve uniform dispersion;

(2), 15 parts of modified nanometer ZnO are added in 15 parts of styrene, after high-speed dispersion 30 minutes, join in the mixture that step (1) forms, stir evenly 0.5 hour; Thereby realize uniform mixing;

(3), add color paste to the mixture formed in step (2)---5 parts of azo pigment, 1 part of surface additive (by BYK-A515, BYK-A555, BYK-S706 according to the ratio of 1:1:1 (mass ratio mixed) and accelerator --- 0.1 part of cobalt isooctanoate, after uniform stirring for 0.5 hours, a weather-resistant nano-composite gel coat was obtained.

Comparative example 2-1,

The amount of "modified nano-ZnO" in step 2) of Example 2 is changed from 15 parts to 0 part, that is, the use of "modified nano-ZnO" is canceled; the rest is the same as in Example 2.

Comparative example 2-2,

The consumption of " modified nanometer ZnO " in embodiment 2 step 2) is changed from 15 parts to 3 parts, all the other are the same as embodiment 2.

Comparative example 2-3,

The consumption of " modified nanometer ZnO " in embodiment 2 step 2) is changed from 15 parts to 30 parts, all the other are the same as embodiment 2.

After the nanocomposite gel coats prepared in Example 2 and Comparative Examples 2-1 to 2-3 were cured to form a film, they were artificially aged for 1000 hours, and their properties are shown in Table 2.

Table 2

ΔE △Yid Whether there is chalking Example 2 1.2 1.4 none Comparative example 2-1 3.7 3.8 Have Comparative example 2-2 1.8 2.4 none Comparative example 2-3 1.2 1.4 none

Example 3.

1), surface modification of nano ZnO:

Weigh 100g of nano-ZnO (particle size 60nm) in 200g of deionized water, stir at high speed for 20 minutes, add 50g of vinyltriethoxysilane, and use 10% (weight ratio) HCl to adjust the pH of the system to 4, and then heat up to 50 ℃, and keep the temperature to stir for 2 hours, filter, and vacuum-dry the obtained filter cake at room temperature to constant weight; obtain the modified nano-ZnO.

2) Preparation of weather-resistant nanocomposite gel coat

(1), add 100 parts of m-benzene-neopentyl glycol type unsaturated polyester resin in the dispersion kettle, add 5 parts of talcum powder under stirring, 3 parts of titanium dioxide, thixotropic agent ---gas phase SiO ₂ (specific surface area 250m ² /g) 1 part, thixotropic stabilizer --- PR6000.2 parts; stirring time 30 minutes, so as to achieve uniform dispersion;

(2), 25 parts of nano ZnO after modification are joined in 25 parts of styrene, join in the mixture that step (1) forms after high-speed dispersion 30 minutes, stir evenly 0.5 hour; Thereby realize uniform mixing;

(3), add color paste to the mixture formed in step (2) --- 1 part of copper phthalocyanine pigment, 0.5 part of surface additive (by BYK-A515, BYK-A555, BYK-S706, JS-V966, etc. Mixed by weight ratio) and accelerator --- 0.4 part of cobalt isooctanoate, after uniform stirring for 0.5 hours, a weather-resistant nano-composite gel coat is obtained.

Comparative example 3-1,

Change the consumption of vinyltriethoxysilane in step 1) of embodiment 3 from 50 g to 60 g; others are the same as embodiment 3.

Comparative example 3-2,

Change the consumption of vinyltriethoxysilane in step 1) of embodiment 3 from 50 g to 15 g; others are the same as embodiment 3.

Comparative example 3-3,

The consumption of the modified nano-ZnO in step 2) of embodiment 3 is changed from 25 parts to 8 parts; other is the same as embodiment 3.

Comparative example 3-4,

Cancel the step 2) of embodiment 3 (2), that is, change step (3) into:

(2), in the mixture that step (1) forms, add nanometer ZnO25 parts after modification and 25 parts of styrenes earlier; Add color paste---1 part of copper phthalocyanine pigment, 0.5 part of surface additive (by Mix BYK-A515, BYK-A555, BYK-S706, JS-V966 in equal weight ratios) and accelerator --- 0.4 parts of cobalt isooctanoate, and stir evenly for 0.5 hours to obtain a weather-resistant nano-composite gel coat.

After the nanocomposite gel coats prepared in Example 3 and Comparative Examples 3-1 to 3-4 were cured and formed into a film, they were artificially accelerated aging for 1000 hours, and their properties are shown in Table 3.

table 3

ΔE △Yid Whether there is chalking Example 3 1.1 1.2 none Comparative example 3-1 1.7 1.4 none Comparative example 3-2 1.9 2.0 none Comparative example 3-3 2.2 2.4 Have Comparative example 3-4 2.8 2.9 Have

Through the above examples and comparative examples, it is found that the weather-resistant nano-composite gel coat prepared by the present invention has better weather resistance, so it can be used on the surface of cooling tower FRP.

Finally, the above-mentioned examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above-mentioned embodiments, and many variations are possible. All deformations that can be directly derived or associated by those skilled in the art from the content disclosed in the present invention should be considered as the protection scope of the present invention.

Claims (3)

1. The weather-resistant nano-composite gel coat is characterized by the following components by weight: 100 parts of unsaturated polyester resin, 10-30 parts of styrene, 10-25 parts of modified nano-ZnO, 5-8 parts of talcum powder 3-5 parts of titanium dioxide, 1-3 parts of thixotropic agent, 0.1-0.2 parts of thixotropic stabilizer, 0.4-1 part of surface additive, 0-10 parts of color paste, 0.1-0.4 part of accelerator; The preparation method of the modified nanometer ZnO is: Add 1 part of nano-ZnO with a particle size of 10-60nm to 1.5-2.5 parts of deionized water, stir at high speed for 10-30 minutes, then add 0.2-0.5 parts of modifier, then adjust the pH to 3-5, and then Raise the temperature to 50-70°C, heat and stir for 1-3 hours, filter, and vacuum-dry the obtained filter cake at room temperature to constant weight; obtain modified nano-ZnO; The modifying agent is γ-methacryloxypropyltrimethoxysilane or vinyltriethoxysilane; The above-mentioned parts are parts by weight. 2. The weather-resistant nano-composite gel coat according to claim 1, characterized in that: Described unsaturated polyester resin is ortho-phenylene-neopentyl glycol type unsaturated polyester resin, m-phenylene-neopentyl glycol type unsaturated polyester resin; The thixotropic agent is gas phase SiO ₂ , with a specific surface area of 150-380m ² /g; The thixotropic stabilizer is PR600 type thixotropic stabilizer; Surface additives are any three or four of BYK-A515, BYK-A555, BYK-S706 and JS-V966; The color paste is azo pigments, lakes, copper phthalocyanines or condensed rings; The accelerator is cobalt isooctanoate. 3. the preparation method of weather-resistant nano-composite gel coat as claimed in claim 1 or 2 is characterized in that comprising the steps: 1) Put the unsaturated polyester resin into the dispersing kettle first, add talcum powder, titanium dioxide, thixotropic stabilizer and thixotropic agent successively under stirring, and disperse evenly; 2), adding modified nano-ZnO to styrene, and adding it to the mixture formed in step 1) after high-speed dispersion; uniformly mixing; 3) Add color paste, surface additives and accelerators to the result of step 2), and stir evenly to obtain a weather-resistant nano-composite gel coat.