CN115011207B

CN115011207B - Epoxy composite coating and preparation method thereof

Info

Publication number: CN115011207B
Application number: CN202210845197.3A
Authority: CN
Inventors: 吴欣航; 黄燕波
Original assignee: NINGBO KEXIN CORROSION CONTROL ENGINEERING CO LTD
Current assignee: NINGBO KEXIN CORROSION CONTROL ENGINEERING CO LTD
Priority date: 2022-07-19
Filing date: 2022-07-19
Publication date: 2023-08-22
Anticipated expiration: 2042-07-19
Also published as: CN115011207A

Abstract

The application relates to the field of coatings, and particularly discloses an epoxy composite coating and a preparation method thereof. The raw materials of the coating comprise 40-60 parts of epoxy resin; 15-25 parts of curing agent; 12-20 parts of organic bentonite; 0.4-0.6 parts of diluent; 2-4 parts of modified fiber; carrying out low-temperature plasma treatment on the fiber to obtain the modified fiber; the preparation method comprises the following steps: the preparation method comprises the following steps: s1: heating liquid epoxy resin to 60-110 ℃, uniformly stirring, then reducing the temperature to room temperature, then adding organic bentonite and a diluent, and uniformly stirring to obtain a mixed matrix; s2: adding the modified fiber and the curing agent into the mixed matrix, and uniformly mixing to obtain the coating material. The coating has the advantages of improving the mechanical property of the coating, and ensuring that the coating is not easy to peel off to influence the protection effect.

Description

Epoxy composite coating and preparation method thereof

Technical Field

The application relates to the technical field of coatings, in particular to an epoxy composite coating and a preparation method thereof.

Background

With the development of ocean resources, the construction of ocean large-scale engineering is in progress. The steel pipe pile has the characteristics of uniform structural stress, high production efficiency, mature and stable process technology, simple construction process, short construction period and the like, and becomes a main basic form adopted by a large ocean engineering structure, but the complexity of an ocean environment causes the basic form steel pipe pile of the ocean engineering to face the problems of durability and the like in the service process, and seriously influences the service life and the safety production of the ocean engineering, so that the development of the long-service-life and high-reliability steel pipe pile protective coating has important economic value and social significance for ensuring the safe and durable operation of ocean important engineering facilities.

At present, the traditional corrosion coating such as an epoxy coating can shield the penetration and diffusion processes of corrosive media such as water, oxygen, chloride ions and the like in the coating in the atmospheric environment, so that an excellent corrosion protection effect is obtained.

With respect to the related art in the above, the inventors consider that there are the following drawbacks: the traditional epoxy coating has poor mechanical properties, and the steel pipe pile protective coating faces the challenges of impact resistance, wear resistance, scratch of heavy load and the like in the process of transporting and inserting the steel pipe pile and in the process of complex construction operation environment and daily maintenance, so that the coating is easy to peel off and loses the protective effect.

Disclosure of Invention

In order to improve the mechanical property of the coating and prevent the coating from peeling off easily to influence the protection effect, the application provides an epoxy composite coating and a preparation method thereof.

In a first aspect, the application provides an epoxy composite coating, which adopts the following technical scheme:

an epoxy composite coating comprises the following raw materials in parts by weight:

40-60 parts of epoxy resin;

15-25 parts of curing agent;

12-20 parts of organic bentonite;

0.4-0.6 parts of diluent;

2-4 parts of modified fiber;

and carrying out low-temperature plasma treatment on the fiber to obtain the modified fiber.

By adopting the technical scheme, the surface weak bonding layer formed by the fiber is crosslinked through low-temperature plasma treatment, so that the surface cohesive strength of the epoxy resin is improved, active groups such as hydroxyl, carboxyl, ester bond, carbonyl and the like are generated on the surface of the fiber, and the chemical bonding of the modified fiber and matrix resin is improved. The low-temperature plasma treatment effectively improves the surface energy of the fiber, improves the infiltration performance of matrix resin on the fiber, forms grooves on the surface of the fiber after the low-temperature plasma treatment, improves the surface roughness, effectively improves the mechanical anchoring with the epoxy resin matrix, and further effectively improves the bonding capability of the modified fiber and the epoxy resin; by adopting the organic bentonite, after the organic bentonite is compounded with the epoxy resin, the organic bentonite has higher rigidity and strength, the organic bentonite is a lamellar aggregate, and strong interaction exists between an epoxy resin macromolecular chain and bentonite lamellar and lamellar organic matters, so that stronger section adhesion can be formed, the wear resistance and impact resistance of the coating can be effectively improved after the organic bentonite is compounded with the epoxy resin, and the organic bentonite has the characteristics of better corrosion resistance, brine erosion resistance, heat resistance and the like; thereby effectively improving the mechanical property of the epoxy composite coating.

Preferably, the material is prepared from the following raw materials in parts by weight:

50-60 parts of epoxy resin;

15-20 parts of curing agent;

15-17 parts of organic bentonite;

0.4-0.5 parts of diluent;

3-4 parts of modified fiber.

By adopting the technical scheme, when the raw materials are mixed, the impact resistance and other mechanical properties of the epoxy composite coating can be further improved.

Preferably, na-bentonite is modified by hexamethylenediamine to obtain the organobentonite.

By adopting the technical scheme, na-bentonite is subjected to organic treatment by hexamethylenediamine, so that cations with larger volume replace original sodium ions between layers, and simultaneously the surface of the Na-bentonite is covered by alkyl chains, so that the bentonite has hydrophilicity to become lipophilicity, the polarity of organic cations on the surface of the organic bentonite is matched with the polarity of polymer molecules in the system, the polymer molecules are induced to migrate towards the layers of the organic bentonite under the affinity effect between the organic cations and the polymer molecules, the bonding performance of the system is effectively improved, the toughening and reinforcing effects on epoxy resin are further achieved, and the mechanical properties of the system are effectively improved.

Preferably, the epoxy resin is specifically bisphenol a type epoxy resin.

By adopting the technical scheme, the bisphenol A epoxy resin has better thermosetting property, can form a cured product with excellent performance with various curing agents and the like, and has good manufacturability; and small molecular volatile is not generated during curing; the cured product has high strength and bonding strength, so that the bonding capability of the composite coating and the carrier can be effectively improved; the obtained system condensate has higher corrosion resistance, and has certain toughness and heat resistance. And when the organic bentonite is obtained by modifying Na-bentonite through hexamethylenediamine through ion exchange and is combined with bisphenol A epoxy resin, the impact resistance of a coating system can be effectively improved.

Preferably, the curing agent is specifically a polyamide curing agent.

By adopting the technical scheme, the polyamide curing agent can not only effectively cure the epoxy resin, but also has better mechanical properties, wear resistance and corrosion resistance; because the carbonyl oxygen atom and the amino nitrogen atom on the amide bond on the polyamide contain lone pair electrons, when the composite coating is applied to the surface of a metal carrier, complexation coordination is performed between metal ions such as iron ions on the metal carrier and the amino nitrogen atom, so that under the action of the metal ions and the amide groups, the bonding capability of the composite coating and the metal carrier is further improved, and the mechanical property of the composite coating is further improved.

Preferably, the fibers are all para-aramid co-fibers.

By adopting the technical scheme, the all-para-aramid fiber has the advantages of ultrahigh strength, high modulus, high temperature resistance, acid and alkali resistance, light weight and the like, good insulativity and ageing resistance, and longer life cycle; and the unique surface structure of the all-para-aramid fiber greatly improves the gripping force of the system, thereby effectively improving the mechanical property of the coating system.

Preferably, the diluent is any one of polypropylene glycol diglycidyl ether, propylene oxide o-tolyl ether or o-tolyl glycidyl ether.

By adopting the technical scheme, the operation performance of the coating system can be improved due to the polypropylene glycol diglycidyl ether, the propylene oxide o-tolyl ether or the o-tolyl glycidyl ether, and the basic performance of the coating system is not influenced; the polypropylene glycol diglycidyl ether has certain flexibility, and can effectively improve mechanical properties such as toughness and the like of an epoxy resin system; the propylene oxide o-tolyl ether and the o-tolyl glycidyl ether have good chemical resistance and water resistance; furthermore, the mechanical properties and the resistance of the coating system can be improved while the operation performance of the coating system is ensured to be improved.

Preferably, the raw materials of the coating also comprise 10-15 parts of polyethersulfone.

By adopting the technical scheme, the polyether sulfone is a high-performance thermoplastic polymer material, has good mechanical properties, stability and the like, the toughness of the epoxy resin can be improved by blending the polyether sulfone with the epoxy resin, the hydroxyl in the polyether sulfone has a promoting effect on the curing of the epoxy resin, the bonding property of the coating is effectively improved by the blending system, and the thermal stability of the coating system before and after curing is improved by introducing the polyether sulfone.

In a second aspect, the application provides a preparation method of an epoxy composite coating, which adopts the following technical scheme: the preparation method of the epoxy composite coating comprises the following steps:

s1: heating liquid epoxy resin to 60-110 ℃, uniformly stirring, then reducing the temperature to room temperature, then adding organic bentonite and a diluent, and uniformly stirring to obtain a mixed matrix;

s2: adding the modified fiber and the curing agent into the mixed matrix, and uniformly mixing to obtain the coating material.

According to the technical scheme, the organic bentonite is used as the improved filler, a reticular cross-linking structure can be formed with the epoxy resin to improve the wear resistance and the shock resistance of the coating, and finally, the modified fiber is used as the reinforced skeleton filler by adding the modified fiber, so that the modified fiber, the organic bentonite and the epoxy resin form a firm reticular cross-linking structure, the interface binding force is enhanced, the mechanical property of the coating is further effectively improved, and the process is simple and convenient to operate.

In summary, the application has the following beneficial effects:

1. according to the application, the epoxy resin, the organic bentonite, the modified fiber and the like are adopted, the grooves are formed on the surface of the modified fiber, so that the surface roughness is improved, the mechanical anchoring with an epoxy resin matrix is effectively improved, the organic bentonite is a lamellar aggregate, and the epoxy resin macromolecular chains have strong interaction with bentonite lamellar and lamellar organic matters, so that the wear resistance and impact resistance of the coating can be effectively improved after the epoxy resin macromolecular chains are compounded with the epoxy resin.

2. In the application, the organic bentonite is preferably obtained by modifying Na-bentonite through hexamethylenediamine by ion exchange, so that the polarity of organic cations on the surface of the organic bentonite is matched with the polarity of polymer molecules in a system, the bonding performance of the system is effectively improved, and the impact resistance of a coating system can be effectively improved when the organic bentonite is combined with bisphenol A epoxy resin by modifying Na-bentonite through hexamethylenediamine by ion exchange.

3. According to the method, the organic bentonite is used as the improved filler, and the modified fiber is used as the reinforced skeleton filler, so that the modified fiber, the organic bentonite and the epoxy resin form a firm reticular cross-linked structure, the interface binding force is enhanced, and the mechanical property of the coating is further effectively improved.

Detailed Description

The present application will be described in further detail with reference to examples.

The sources of raw materials used in the present application are as follows:

TABLE 1 sources of raw materials

Raw material name	Purchase source
		Bisphenol A type epoxy resin	Gallery Rong Jie anticorrosive Material Co.Ltd
Na-bentonite	Bentonite mineral Co Ltd in Santai county of Sichuan province
		Hexamethylenediamine	Nanchang Xingyi Technology Industrial Co., Ltd.
Polyamide curing agent	GUANGDONG SHUNTIAN NEW MATERIAL Co.,Ltd.
		All-para-aramid copolyfiber	Dongguan city Xuan plastic materials Co., ltd
Polypropylene glycol diglycidyl ether	Lifan chemical Co Ltd
		Propylene oxide o-tolyl ether	Wuhan Hua Xiangke Jietexilate Co.Ltd
O-tolyl glycidyl ether	Wuhan Hua Xiangke Jietexilate Co.Ltd
		Polyether sulfone	Dongguan Site Steel Plastic Material Co., ltd

Preparation example of organic Bentonite

Preparation example 1

100g of Na-bentonite and 400g of deionized water are added into a 2000ml beaker, soaked for 2 hours, sheared and pulped by a stirrer, the rotating speed is 600rmp, the time is about 40 minutes, the upper suspension is taken, 5 percent hydrochloric acid of the weight of the Na-bentonite is added into the suspension, the stirring reaction is carried out for 4 hours at normal temperature, and then the thick slurry is washed to be neutral.

Placing the thick slurry into a 1000ml flask, adding 3.28g of hexamethylenediamine and 400ml of deionized water, heating to 80 ℃ and stirring for 2-4 hours to obtain upper-layer slurry and lower-layer clear water, taking the upper-layer slurry, filtering out water under pressure, drying a filter cake below 150 ℃, and crushing to 300 meshes to obtain the organic bentonite.

Preparation example 2

100g of Ca-bentonite and 400g of deionized water are added into a 2000ml beaker, soaked for 2 hours, sheared and pulped by a stirrer, the rotating speed is 600rmp, the time is about 40 minutes, the upper suspension is taken, 5 percent hydrochloric acid of Na-bentonite weight is added into the suspension, the stirring reaction is carried out for 4 hours at normal temperature, and then the thick slurry is washed to be neutral.

Placing the thick slurry into a 1000ml flask, adding 3.28g of cetyltrimethylammonium chloride and 400ml of deionized water, heating to 80 ℃ and stirring for 2-4 hours to obtain upper-layer slurry and lower-layer clear water, taking the upper-layer slurry, filtering out water under pressure, drying a filter cake below 150 ℃, and crushing to 300 meshes to obtain the organic bentonite.

Examples

Example 1

The preparation method of the epoxy composite coating comprises the following steps:

s1: heating liquid epoxy resin to 60 ℃, uniformly stirring, then reducing the temperature to room temperature, then adding organic bentonite and a diluent, and uniformly stirring to obtain a mixed matrix;

In this example, bisphenol propane epoxy resin was used as the epoxy resin, the organobentonite prepared in preparation example 1 was used as the diluent, and polypropylene glycol diglycidyl ether was used as the diluent; the curing agent was diethylaminopropylamine, available from Jiangsu Pu Le Si Biotech Co.

In the embodiment, a low-temperature plasma device is used for treating the surface of the carbon fiber to obtain the modified fiber, air is used as a fiber surface treatment medium in an atmosphere environment to generate low-temperature plasma, and the surface of the fiber tow in motion is bombarded by the low-temperature plasma. The low-temperature plasma is jet type atmospheric low-temperature plasma. The running speed of the fiber tows is 80m/h; the working environment temperature of the fiber treatment is 15 ℃; the gap between the fiber and the plasma emission device is 8mm; the humidity of the fiber surface treatment environment is 60%; the fiber surface treatment power range is 500W/bundle silk; the surface treatment temperature of the low-temperature plasma fiber is 80 ℃. The jet type atmospheric low-temperature plasma emission device is PG-1000Z type equipment.

Examples 2 to 3

A preparation method of the epoxy composite coating is different from the preparation method of the epoxy composite coating in example 1 in that the liquid epoxy resin is heated to 85 ℃ in S1 of the example 2, the liquid epoxy resin is heated to 110 ℃ in S1 of the example 3, and raw material components and corresponding weight parts are shown in the table 2.

TABLE 2 weight (kg) of the raw materials in examples 1 to 3

Component (A)	Example 1	Example 2	Example 3
				Epoxy resin	40	50	60
Curing agent	15	20	25
				Organic bentonite	20	16	12
Diluent agent	0.6	0.5	0.4
				Modified fiber	4	3	2

Example 4

The preparation method of the epoxy composite coating is different from the preparation method of the example 2 in that the organic bentonite prepared in the preparation method of the example 2 is adopted.

Example 5

The preparation method of the epoxy composite coating is different from the embodiment 4 in that bisphenol A type epoxy resin is adopted as the epoxy resin in the embodiment.

Example 6

The preparation method of the epoxy composite coating is different from example 5 in that polyamide curing agent is adopted as curing agent in the example.

Example 7

The preparation method of the epoxy composite coating is different from example 6 in that the modified fiber is obtained by treating the surface of the all-para-aramid copolymer fiber by using a low-temperature plasma device.

Example 8

The preparation method of the epoxy composite coating is different from example 7 in that propylene oxide o-tolyl ether is adopted as the diluent in the example.

Example 9

A method for preparing an epoxy composite coating is different from example 7 in that o-tolyl glycidyl ether is adopted as a diluent in the example.

Example 10

The preparation method of the epoxy composite coating is different from example 7 in that the coating raw material of the embodiment also comprises 10 parts of polyethersulfone; the preparation method comprises the following steps:

s1: heating liquid epoxy resin polyethersulfone to 85 ℃, uniformly stirring, reducing the temperature to room temperature, then adding organic bentonite, polyethersulfone and a diluent, and uniformly stirring to obtain a mixed matrix;

s2: adding the modified fiber and the curing agent into the mixed matrix, and uniformly mixing and stirring to obtain the coating material.

Example 11

The preparation method of the epoxy composite coating is different from example 10 in that the coating raw material of the example also comprises 12 parts of polyethersulfone.

Example 12

The preparation method of the epoxy composite coating is different from example 10 in that the coating raw material of the example also comprises 15 parts of polyethersulfone.

Comparative example

Comparative example 1

A method for preparing an epoxy composite coating, which is different from example 1 in that the raw material does not include organic bentonite.

Comparative example 2

A method for preparing an epoxy composite coating, which is different from example 1 in that the organobentonite is replaced by equivalent sodium bentonite.

Comparative example 3

A method for preparing an epoxy composite coating, which is different from example 1 in that the modified fiber is replaced by an equivalent amount of carbon fiber.

Comparative example 4

A method of preparing an epoxy composite coating, which differs from example 1 in that the raw material does not include modified fibers.

Performance test

1. According to SY/T0315-2013, adopting an impact tester to detect impact resistance of the coating, adopting a punch with phi 25mm, wherein the test temperature is 23+/-2 ℃ and the impact energy is 30J, measuring the number of leakage points of three test pieces, and taking an average value;

2. and (3) carrying out wear resistance test detection on the coating according to GB/T1768-2006, selecting a Cs-10 rubber grinding wheel, selecting a counterweight of 1Kg, regulating the revolution to 1000 revolutions, and calculating the average mass loss of the three test plates to be accurate to 0.1mg.

3. The scratch resistance test detection is carried out on the coating by adopting a scratch tester according to SY/T4113-2007, the scratch depth of each measuring point is recorded by adopting a 50Kg load, and the average value of the scratch depths of each measuring point is taken to be accurate to 1 mu m.

4. According to GB/T5210-2006, a tensile testing machine is adopted, the adhesive strength/Mpa of the coating is detected by a drawing method, and the testing temperature is 23+/-2 ℃.

TABLE 3 Table 3

As can be seen by combining examples 1-4 and comparative examples 1-2 and combining Table 3, examples 1-3 are free of leakage points, and the mass loss, scratch depth and bonding strength of examples 1-4 are better than those of comparative examples 1-2, which shows that the mechanical property and wear resistance of the coating system can be effectively improved after the organobentonite is added into the system.

As can be seen from a combination of examples 1-3 and 5 and table 3, examples 1-3 and 5 are free of leakage points, and example 5 has a scratch depth less than that of examples 1-3, and example 5 has a bond strength greater than that of examples 1-3, indicating that the use of bisphenol a type epoxy resin can increase the bond strength of the coating system and allow the coating system to maintain good impact resistance.

As can be seen from the combination of examples 5 and 6 and the combination of table 3, examples 5 and 6 have no leakage points, and the scratch depths and wear resistances of examples 5 and 6 are not very different, but the bonding strength of example 6 is better than that of example 5, which indicates that the polyamide curing agent can not only effectively cure epoxy resin, but also improve the bonding capability of the composite coating and the metal carrier, and further improve the mechanical properties of the composite coating.

As can be seen from examples 6 and 7 in combination with table 3, examples 5 and 6 have no leakage points, and the adhesive strength and abrasion resistance of example 7 and example 6 are not very different, but the scratch depth of example 7 is better than that of example 6, which indicates that the mechanical properties such as strength of the coating system can be effectively improved by using the all-para-aramid copolymerized fiber.

As can be seen from the combination of example 2 and comparative examples 3-4 and table 3, example 2 has no leakage points, and examples 1-4 have better mass loss, scratch depth and bond strength than comparative examples 1-2, demonstrating that the modified fibers obtained by low temperature plasma treatment can effectively improve the mechanical properties and wear resistance of the coating system.

Examples 2 and 8-9, in combination with Table 3, show that examples 2 and 8-9 are free of leakage points, and that example 2 is superior to examples 8-9 in bond strength, scratch depth, and abrasion resistance, but is not significant enough to demonstrate that the use of any of polypropylene glycol diglycidyl ether, propylene oxide o-tolyl ether, or o-tolyl glycidyl ether as a diluent can improve the mechanical properties and resistance of the coating system, but is not significant.

It can be seen from the combination of examples 7 and examples 10-12 and Table 3 that examples 7 and 10-12 are free of leakage points and that example 7 is superior to examples 10-12 in terms of bond strength, scratch depth and abrasion resistance, indicating that the addition of polyethersulfone to the system can improve the mechanical properties and resistance of the system.

The present embodiment is only for explanation of the present application and is not to be construed as limiting the present application, and modifications to the present embodiment, which may not creatively contribute to the present application as required by those skilled in the art after reading the present specification, are all protected by patent laws within the scope of claims of the present application.

Claims

1. The epoxy composite coating is characterized by comprising the following raw materials in parts by weight:

50 parts of epoxy resin;

20 parts of curing agent;

16 parts of organic bentonite;

0.5 parts of diluent;

3 parts of modified fiber;

12 parts of polyether sulfone;

the fiber is treated by low-temperature plasma to obtain the modified fiber, air is used as a fiber surface treatment medium in an atmosphere environment to generate low-temperature plasma, the surface of a fiber tow in motion is bombarded by the low-temperature plasma, the low-temperature plasma is jet-type atmospheric low-temperature plasma, and the running speed of the fiber tow is 80m/h; the working environment temperature of the fiber treatment is 15 ℃; the gap between the fiber and the plasma emission device is 8mm; the humidity of the fiber surface treatment environment is 60%; the fiber surface treatment power range is 500W/bundle silk; the surface treatment temperature of the low-temperature plasma fiber is 80 ℃;

the fiber is an all-para-aramid copolymer fiber;

carrying out ion exchange modification on Na-bentonite by hexamethylenediamine to obtain the organic bentonite; the epoxy resin is bisphenol A type epoxy resin; the curing agent is specifically a polyamide curing agent; the diluent is any one of polypropylene glycol diglycidyl ether and o-tolyl glycidyl ether.

2. The method for preparing the epoxy composite coating according to claim 1, wherein the method comprises the following steps: the preparation method comprises the following steps:

s1: heating epoxy resin to 60-110 ℃, uniformly stirring, then reducing the temperature to room temperature, then adding organic bentonite and a diluent, and uniformly stirring to obtain a mixed matrix;

s2: adding the modified fiber and the curing agent into the mixed matrix, and uniformly mixing to obtain the coating.