1. A plant-based multifunctional toughening epoxy resin is characterized by comprising the following components:

a plant polyene phenolic glycidyl ether represented by formula 1 or 2;

n-27-31 in said formula 1 or 2;

a compound containing a dihydroxy group;

a catalyst;

wherein the molar ratio of the plant polyene phenolic glycidyl ether to the compound containing a dihydroxy group is 2: 1-2;

wherein the dosage of the catalyst is 0.1-1%;

2. the vegetable-based polyfunctional toughening-type epoxy resin of claim 1, wherein the catalyst comprises any one or more of benzyltrimethylammonium bromide, benzyltriethylammonium bromide, benzyltributylammonium bromide, tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, hexadecyltrimethylammonium bromide, boron trifluoride etherate, triphenylphosphine, sodium hydroxide, or potassium hydroxide.

3. The plant-based polyfunctional toughening-type epoxy resin according to claim 1, wherein the compound having a dihydroxy group is one or more of bisphenol a, bisphenol S, polypropylene glycol, and polyethylene glycol.

4. The method for preparing the plant-based multifunctional toughened epoxy resin according to claims 1 to 3, comprising the steps of:

adding the plant polyene phenolic glycidyl ether and the compound containing the dihydroxy into a reaction kettle, heating to 60-100 ℃, adding the catalyst to perform an epoxy ring-opening reaction, and keeping the temperature at 80-120 ℃ for 2-8 hours to obtain the plant-based multifunctional toughening epoxy resin.

Background

Epoxy resin anticorrosive paint is the most widely applied paint in anticorrosive paint. Generally, a coating material containing a large number of epoxy groups in its composition is called an epoxy paint, and its resin is a polymer compound having a molecular structure containing at least two epoxy groups. The paint is suitable for coating steel structures in severe corrosive environments such as sea, industrial areas, chemical plants, coasts, concrete and the like, and is particularly suitable for coating the inner surfaces of various storage tanks.

The epoxy resins used in the epoxy coating are mainly bisphenol a type, bisphenol F type, novolac epoxy and the like. The main variety of epoxy resin anticorrosive paint is bi-component paint, which consists of base material and curing agent.

There are other one-component, self-drying types, but the properties are far from the same as those of two-component coatings.

In the prior art, the molecular structure of epoxy resin used for producing epoxy resin anticorrosive paint contains active epoxy groups, and the epoxy resin can generate cross-linking reaction with various curing agents (aromatic amine, aliphatic amine, modified amine, polyamide and the like) to form insoluble high polymer with a three-dimensional network structure.

Epoxy resin condensate has excellent chemical resistance, low shrinkage, high bonding strength, high mechanical strength and excellent electrical insulation, so the epoxy resin condensate is widely used in the fields of coatings, adhesives, printing ink and the like, but raw material petroleum for producing epoxy resin is a disposable resource, the price of petroleum is continuously increased, and the production cost is continuously increased.

However, the impact strength characteristic of epoxy materials is not suitable for many applications, and for more convenient application, it is necessary to increase the crosslinking density of epoxy resin, reduce the brittleness of epoxy resin, and achieve excellent comprehensive performance, which is the most urgent problem at present.

The existing toughening approaches of epoxy resin mainly comprise the following two types:

(1) rubber elastomer, thermoplastic resin, rigid inorganic filler, thermotropic liquid crystal polymer and the like are utilized to form a two-phase structure for toughening;

(2) the thermoplastic continuously penetrates through the epoxy resin network to form a semi-interpenetrating network polymer for toughening;

among them, the toughening of epoxy resin by rubber elastomer is an early toughening method, but this method has the disadvantages of lowering the modulus of the material and insufficient heat resistance while improving the toughness, thus limiting its application in some high performance fields.

The Chinese academy of sciences chemical institute early patent 99108080.7 discloses an epoxy resin composition toughened by hydroxyl-terminated liquid rubber, wherein the fracture energy of the composition after curing is 689J/m²The bending strength is 137.4Mpa, the bending modulus is 2.35Gpa, and the toughening effect is obvious. The method only meets the performance by adding the toughening agent, and can not meet the requirements in the field of higher heavy corrosion resistance.

Patent CN102924690 discloses an epoxy resin material for toughening and reinforcing hyperbranched polyether epoxy resin and a preparation method thereof, but the process is complex in synthesis and has unobvious cost advantage, and cannot be widely popularized in industrial products.

In the field of coatings, epoxy resin diluents, tetradecanol glycidyl ether and cardanol glycidyl ether are usually added to increase the toughness of the resin, but the toughened resin is monofunctional and cannot be crosslinked with a system to form a dense net, so that the corrosion resistance of a coating film is influenced.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a plant-based multifunctional toughening type epoxy resin and a preparation method thereof. The epoxy resin material is toughened and the crosslinking density is increased and a coating film is formed through simple components and a synthesis process, and the produced epoxy coating has excellent anticorrosion and waterproof functions.

A plant-based multifunctional toughening epoxy resin comprises the following components:

a plant polyene phenolic glycidyl ether represented by formula 1 or 2;

n-27-31 in said formula 1 or 2;

a compound containing a dihydroxy group;

a catalyst;

wherein the molar ratio of the plant polyene phenolic glycidyl ether to the compound containing a dihydroxy group is 2: 1-2;

wherein the dosage of the catalyst is 0.1-1%;

in a preferred embodiment of the present invention, the catalyst comprises any one or more of benzyltrimethylammonium bromide, benzyltriethylammonium bromide, benzyltributylammonium bromide, tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, hexadecyltrimethylammonium bromide, boron trifluoride etherate, triphenylphosphine, sodium hydroxide or potassium hydroxide.

In a preferred embodiment of the present invention, the compound containing a dihydroxy group is any one or more of bisphenol a, bisphenol S, polypropylene glycol, or polyethylene glycol.

A preparation method of a plant-based multifunctional toughening epoxy resin comprises the following steps:

adding the plant polyene phenolic glycidyl ether and the compound containing the dihydroxy into a reaction kettle, heating to 60-100 ℃, adding the catalyst to perform an epoxy ring-opening reaction, and keeping the temperature at 80-120 ℃ for 2-8 hours to obtain the plant-based multifunctional toughening epoxy resin.

The invention has the beneficial effects that:

the plant-based multifunctional toughened epoxy resin prepared by the invention can replace solid epoxy resin prepared from petroleum raw materials, and is more environment-friendly;

the toughened plant-based multifunctional toughened epoxy resin has the flexibility of 1mm, the adhesive force of 1 grade and the toughening effect of obviously improved.

Detailed Description

Example 1

Adding 293.7g of plant polyene phenolic glycidyl ether, 55.9g of bisphenol A and 0.4g of tetrabutyl ammonium bromide serving as a catalyst into a 500ml reaction flask inner kettle, and reacting for 5 hours at 120 ℃; synthesizing the plant-based multifunctional toughened epoxy resin.

Example 2

Adding 293.7g of plant polyene phenolic glycidyl ether, 55.9g of bisphenol A and 0.1g of catalyst sodium hydroxide into a 500ml reaction flask inner kettle, and reacting for 5 hours at 100 ℃; synthesizing the plant-based multifunctional toughened epoxy resin.

Example 3

Adding 293.7g of plant polyene phenolic glycidyl ether, 55.9g of bisphenol A and 0.1g of boron trifluoride diethyl etherate serving as a catalyst into a 500ml reaction flask inner kettle, and reacting for 3 hours at 80 ℃; synthesizing the plant-based multifunctional toughened epoxy resin.

Example 4

Adding 293.7g of plant polyene phenolic glycidyl ether, 55.9g of bisphenol A and 0.3g of catalyst triphenylphosphine into a 500ml reaction flask inner kettle, and reacting for 3 hours at 120 ℃; synthesizing the toughened novel epoxy resin.

Preparing a clear paint film of 200 mu m from the plant-based multifunctional toughened epoxy resin scratch film prepared by the invention; drying for 24 hours at room temperature; the flexibility and adhesion were tested and the results are shown in table 1:

as can be seen from Table 1, the adhesion and flexibility of the toughened product are both significantly improved.

Having thus described the basic principles of the present invention, its principal features and advantages, the present invention is not limited by the foregoing embodiments, but is susceptible to various changes and modifications without departing from the principles and scope of application, which are intended to be covered by the appended claims and their equivalents.