CN115011207A

CN115011207A - Epoxy composite coating and preparation method thereof

Info

Publication number: CN115011207A
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: 2022-09-06
Anticipated expiration: 2042-07-19
Also published as: CN115011207B

Abstract

The application relates to the field of coatings, and particularly discloses an epoxy composite coating and a preparation method thereof. The raw material of the coating comprises 40-60 parts of epoxy resin; 15-25 parts of a curing agent; 12-20 parts of organic bentonite; 0.4-0.6 part 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 the liquid epoxy resin to 60-110 ℃, uniformly stirring, reducing the temperature to room temperature, then adding the organic bentonite and the diluent, and uniformly stirring to obtain a mixed matrix; s2: and 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 marine resources, the construction of marine large-scale engineering is in the spotlight. 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 foundation form adopted by a large-scale ocean engineering structure, but the complexity of the ocean environment causes the problem of durability and the like of the steel pipe pile in the service process of the foundation form of the ocean engineering, and the service life and the safe production of the ocean engineering are seriously influenced, so that the development of the protective coating of the steel pipe pile with long service life and high reliability has important economic value and social significance for ensuring the safe and durable operation of major ocean engineering facilities.

At present, the traditional corrosion coating such as an epoxy coating can shield the permeation and diffusion processes of corrosive media such as water, oxygen, chloride ions and the like in the coating in the atmospheric environment, thereby obtaining excellent corrosion protection effect.

With respect to the related art among the above, the inventors consider that the following drawbacks exist: the traditional epoxy coating has poor mechanical property, and the protective coating of the steel pipe pile faces the challenges of scratch resistance, wear resistance and heavy load and the like in the transportation and inserting process of the steel pipe pile, the complex construction operation environment and the routine maintenance process, 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 enable the coating not to be easy to peel off to influence the protection effect, the application provides the epoxy composite coating and the preparation method thereof.

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

an epoxy composite coating is prepared from the following raw materials in parts by weight:

40-60 parts of epoxy resin;

15-25 parts of a curing agent;

12-20 parts of organic bentonite;

0.4-0.6 part 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 the matrix resin is improved. The low-temperature plasma treatment effectively improves the surface energy of the fiber, improves the infiltration performance of matrix resin to the fiber, and also forms a groove on the surface of the fiber after the low-temperature plasma treatment, so that the surface roughness is improved, the mechanical anchoring with an epoxy resin matrix is effectively improved, and the bonding capability of the modified fiber and the epoxy resin is further effectively improved; 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 a macromolecular chain of the epoxy resin has strong interaction with a bentonite lamellar and a lamellar organic matter, so that stronger cross-section bonding can be formed; thereby effectively improving the mechanical property of the epoxy composite coating.

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

50-60 parts of epoxy resin;

15-20 parts of a curing agent;

15-17 parts of organic bentonite;

0.4-0.5 part of diluent;

3-4 parts of modified fiber.

By adopting the technical scheme, the mechanical properties of the epoxy composite coating, such as impact resistance, can be further improved when the raw materials are proportioned.

Preferably, the organic bentonite is obtained by modifying Na-bentonite with hexamethylenediamine through ion exchange.

By adopting the technical scheme, Na-bentonite is organically treated by hexamethylenediamine, so that cations with larger volume replace original sodium ions between layers, and meanwhile, the surface of the bentonite is covered by alkyl chains, so that the bentonite has hydrophilicity and becomes lipophilic, the polarity of the organic cations on the surface of the organobentonite is matched with the polarity of polymer molecules in a system, the polymer molecules are induced to migrate between layers of the organobentonite under the affinity action between the cations and the polymer molecules, the bonding property of the system is effectively improved, the toughening and reinforcing effects on epoxy resin are further achieved, and the mechanical property of the system is 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 substance with excellent performance with various curing agents and the like, and has good manufacturability; and does not generate small molecule volatile 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; and the obtained system condensate has higher corrosion resistance, certain toughness and heat resistance. And when the organic bentonite obtained by modifying Na-based bentonite through hexamethylenediamine through ion exchange is combined with the 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 effectively play a role in curing the epoxy resin, and the polyamide has good mechanical property, is wear-resistant and corrosion-resistant; because the carbonyl oxygen atom and the amino nitrogen atom on the amido bond of the polyamide contain lone-pair electrons, when the composite coating is applied to the surface of a metal carrier, the complex coordination action is generated between metal ions such as iron ions and the like on the metal carrier and the amino nitrogen atom, so that the binding capacity of the composite coating and the metal carrier is further improved under the action between the metal ions and the amido group, and the mechanical property of the composite coating is further improved.

Preferably, the fiber is full para-aramid copolymer fiber.

By adopting the technical scheme, the fully para-aramid copolymer fiber has ultrahigh strength, high modulus, high temperature resistance, acid and alkali resistance, light weight and the like, has good insulativity and ageing resistance, and has a longer life cycle; and the unique surface structure of the full para-aramid copolymerized fiber greatly improves the grasping 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 polypropylene glycol diglycidyl ether, the propylene oxide o-tolyl ether or the o-tolyl glycidyl ether can improve the operation performance of the coating system without influencing the basic performance of the coating system; the polypropylene glycol diglycidyl ether has certain flexibility, and can effectively improve mechanical properties such as toughness of an epoxy resin system; the propylene oxide o-tolyl ether and the o-tolyl glycidyl ether have better chemical resistance and water resistance; further, the mechanical property and the resistance of the coating system can be improved while the operation property of the coating system is ensured to be improved.

Preferably, the raw material of the coating also comprises 10-15 parts of polyether sulfone.

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

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

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

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

By adopting the technical scheme, the organic bentonite is used as the improved filler, the organic bentonite and the epoxy resin can form a net-shaped cross-linked structure to improve the wear resistance and the shock resistance of the coating, and finally the modified fiber is added and used as the reinforced framework filler, so that the modified fiber, the organic bentonite and the epoxy resin form a firm net-shaped cross-linked structure, the interface bonding force is enhanced, the mechanical property of the coating is effectively improved, and the process is simple and convenient to operate.

In summary, the present application has the following beneficial effects:

1. because this application adopts epoxy, organobentonite and modified fiber etc. to form the slot through modified fiber surface, surface roughness improves, effectively improves the mechanical anchor with the epoxy resin base member, and organobentonite is the lamella aggregate moreover, has strong interact between epoxy macromolecular chain and bentonite lamella, the lamella organic matter, can effectively improve the wear-resisting and shock resistance of coating after compounding with epoxy.

2. The preferable adoption in this application passes through ion exchange modification with Na-group bentonite through hexanediamine and obtains organobentonite for organocation polarity on organobentonite surface and the polymer molecule polarity phase-match in the system effectively improve the associative performance of system, and through adopting and passing through ion exchange modification with Na-group bentonite through hexanediamine and obtaining organobentonite and bisphenol A type epoxy resin when combining, can effectively improve the shock resistance of coating system.

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

Detailed Description

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

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

TABLE 1 sources of raw materials

Name of raw materials	Purchase source
		Bisphenol A epoxy resin	Rongjie corrosion protection materials Co Ltd of corridor Fang
Na-based bentonite	Dayu bentonite mining Co Ltd in san Din county, Sichuan province
		Hexamethylene diamine	Nanchang Xingyi Technology Industrial Co., Ltd.
Polyamide curing agent	GUANGDONG SHUNTIAN NEW MATERIAL Co.,Ltd.
		Full para-aramid copolymer fiber	Dongguan City Zhengxuan Plastic Material Co Ltd
Polypropylene glycol diglycidyl ether	Shandong province Lifan chemical Co., Ltd
		Propylene oxide o-tolyl ether	Wuhan Hua Xianzhi Kejie Biotech limited Co
O-tolyl glycidyl ether	Wuhanhua detailed scientific biotechnology limited
		Polyether sulfone	Dongguan sai Steel Plastic collagen Co Ltd

Preparation example of Organobentonite

Preparation example 1

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

And (3) putting the thick slurry into a 1000ml flask, adding 3.28g of hexamethylenediamine and 400ml of deionized water, heating to 80 ℃, stirring for 2-4 hours to obtain the upper slurry and lower layer of clear water, taking the upper slurry, press-filtering to remove water, drying the filter cake at the temperature of below 150 ℃, and crushing to 300 meshes to obtain the organic bentonite.

Preparation example 2

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

And (3) placing the thick slurry into a 1000ml flask, adding 3.28g of hexadecyltrimethylammonium chloride and 400ml of deionized water, heating to 80 ℃, stirring for 2-4 hours to obtain the upper slurry and lower clear water, filtering the upper slurry under pressure to remove water, drying the filter cake at the temperature below 150 ℃, and crushing to 300 meshes to obtain the organic bentonite.

Examples

Example 1

A preparation method of an epoxy composite coating comprises the following steps:

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

In the embodiment, the epoxy resin is bisphenol propane epoxy resin, the organic bentonite prepared in the preparation example 1 is adopted, and polypropylene glycol diglycidyl ether is adopted as a diluent; the curing agent adopts diethylaminopropylamine which is purchased from Jiangsu plectrum Biotech limited company.

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

Examples 2 to 3

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

TABLE 2 materials and weights (kg) thereof in examples 1-3

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

Example 4

The difference between this example and example 2 is that the organic bentonite prepared in preparation example 2 is used in this example.

Example 5

The difference between the embodiment and the embodiment 4 is that the epoxy resin in the embodiment adopts bisphenol a type epoxy resin.

Example 6

The difference between the embodiment and the embodiment 5 is that the curing agent in the embodiment adopts a polyamide curing agent.

Example 7

The difference between the embodiment and the embodiment 6 is that the embodiment uses a low-temperature plasma device to treat the surface of the full para-aramid copolymer fiber to obtain a modified fiber.

Example 8

The difference between the embodiment and the embodiment 7 is that the diluent in the embodiment adopts propylene oxide o-tolyl ether.

Example 9

This example is different from example 7 in that o-tolyl glycidyl ether was used as a diluent in this example.

Example 10

The difference between the embodiment and the embodiment 7 is that the coating raw material of the embodiment further comprises 10 parts of polyether sulfone; the preparation method comprises the following steps:

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

s2: and 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 difference between the embodiment and the embodiment 10 is that the coating raw material of the embodiment further comprises 12 parts of polyether sulfone.

Example 12

The difference between the embodiment and the embodiment 10 is that the coating raw material of the embodiment further comprises 15 parts of polyether sulfone.

Comparative example

Comparative example 1

The preparation method of the epoxy composite coating is different from the preparation method of the embodiment 1 in that the raw materials do not comprise organic bentonite.

Comparative example 2

The preparation method of the epoxy composite coating is different from the preparation method of the embodiment 1 in that the organic bentonite is replaced by the same amount of sodium bentonite.

Comparative example 3

The preparation method of the epoxy composite coating is different from the embodiment 1 in that the modified fiber is replaced by the same amount of carbon fiber.

Comparative example 4

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

Performance test

1. Detecting the impact resistance of the coating by adopting an impact tester according to SY/T0315-2013, measuring the number of leakage points of three test pieces by adopting a punch with the diameter of phi 25mm, the test temperature is 23 +/-2 ℃, the impact energy is 30J, and averaging;

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

3. And (3) carrying out scratch resistance test detection on the coating by adopting a scratch testing machine according to SY/T4113-2007, recording the scratch depth of each measuring point by adopting a 50Kg load, and taking the average value of the scratch depths of each measuring point to be accurate to 1 mu m.

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

TABLE 3

As can be seen by combining examples 1-4 and comparative examples 1-2 and combining Table 3, no leakage point exists in examples 1-3, and the quality loss, the scratch depth and the bonding strength of examples 1-4 are all superior to those of comparative examples 1-2, which shows that the mechanical property and the wear resistance of a coating system can be effectively improved after the organic bentonite is added into the system.

As can be seen by combining examples 1-3 and 5 with Table 3, examples 1-3 and 5 all have no missing dots, and the depth of the scratch of example 5 is less than that of examples 1-3, and the adhesive strength of example 5 is greater than that of examples 1-3, indicating that the use of bisphenol A epoxy resin can improve the adhesive strength of the coating system and maintain good impact resistance of the coating system.

It can be seen by combining examples 5 and 6 and table 3 that there is no missing point in examples 5 and 6, and the scratch depth and the wear resistance of examples 5 and 6 are not much different, but the adhesive strength of example 6 is better than that of example 5, which indicates that the polyamide curing agent can effectively cure epoxy resin, improve the bonding ability 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, no missing dot exists in examples 5 and 6, and the bonding strength and abrasion resistance of example 7 are not much different from those of example 6, but the scratch depth of example 7 is better than that of example 6, which shows that the all-para-aramid copolymer fiber can effectively improve the mechanical properties such as the strength of the coating system.

It can be seen from the combination of example 2 and comparative examples 3-4 and table 3 that, there is no leak point in example 2, and the mass loss, scratch depth and bond strength of examples 1-4 are all better than those of comparative examples 1-2, which shows that the modified fiber obtained by low temperature plasma treatment can effectively improve the mechanical property and wear resistance of the coating system.

As can be seen from examples 2 and 8-9 in combination with Table 3, there were no missing dots in examples 2 and 8-9, and the adhesive strength, scratch depth and abrasion resistance of example 2 were superior to those of examples 8-9, but were not sufficiently significant, indicating that the use of any one 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 the effect was not significant.

Combining example 7 and examples 10-12 with Table 3, it can be seen that there are no missing dots in examples 7 and 10-12, and that the adhesive strength, scratch depth and abrasion resistance of example 7 are better than those of examples 10-12, indicating that the mechanical properties and resistance of the system can be improved by adding polyethersulfone to the system.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

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

40-60 parts of epoxy resin;

15-25 parts of a curing agent;

12-20 parts of organic bentonite;

0.4-0.6 part of diluent;

2-4 parts of modified fiber;

2. The epoxy composite coating of claim 1, wherein: the feed is prepared from the following raw materials in parts by weight:

50-60 parts of epoxy resin;

15-20 parts of a curing agent;

15-17 parts of organic bentonite;

0.4-0.5 part of diluent;

3-4 parts of modified fiber.

3. The epoxy composite coating of claim 1, wherein: and (3) carrying out ion exchange modification on Na-based bentonite by using hexamethylenediamine to obtain the organic bentonite.

4. The epoxy composite coating of claim 3, wherein: the epoxy resin is specifically bisphenol A epoxy resin.

5. The epoxy composite coating of claim 1, wherein: the curing agent is specifically a polyamide curing agent.

6. The epoxy composite coating of claim 1, wherein: the fibers are all.

7. The epoxy composite coating of claim 1, wherein: the diluent is one of o-ether and o-ether.

8. The epoxy composite coating according to claim 1, wherein: the raw material of the coating also comprises 10-15 parts of polyether sulfone.

9. The method for preparing an epoxy composite coating according to any one of claims 1 to 7, wherein: the preparation method comprises the following steps: