A process for the preparation of epoxy imine solid plastic materials in one step without solvent

Abstract

The application provides a method for preparing an epoxy imine solid plastic material by a solvent-free one-step method and belongs to the technical field of solid plastic materials. The method comprises the following steps: mixing a polyaldehyde, an aromatic polyprimary amine curing agent and an epoxy resin to obtain an epoxy imine prepolymer with fluidity. Then, the epoxy imine prepolymer is transferred into a mold, and after being cured in an oven or a hot press at 160-210 DEG C for 2-6 hours, an epoxy imine solid plastic material is obtained. In the reaction system of the application, no solvent is involved, and the epoxy imine solid plastic material can be prepared by a simple one-step method, thereby providing a new solution for the low-cost industrial production of the solid plastic material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid plastic materials, in particular to a method for preparing an epoxy imine solid plastic material by a one-step solvent-free method. BACKGROUND

[0002] Epoxy thermosetting resins have excellent mechanical strength, stability and electrical insulation performance, and are widely used in different fields such as composite materials, coatings, etc. However, the permanent crosslinking network of epoxy resins hinders the repair, recycling and utilization of the materials. The introduction of dynamic exchangeable imine bonds in the epoxy resin network forms a dynamic crosslinking network in the system, which can solve the above-mentioned shortcomings of traditional epoxy resins.

[0003] Through the search of the published literature (such as invention patent CN113621137A, invention patent CN115772276A, etc.), it is found that the currently prepared epoxy imine solid plastic is mainly prepared by the following route: dissolving polybasic primary amine and polyaldehyde monomer in a solvent to synthesize an imine bond-containing curing agent, then purifying the curing agent and removing the solvent. The prepared imine curing agent is then compounded with epoxy resin and cured to prepare an epoxy imine solid plastic material.

[0004] The two-step method for preparing the solid plastic has a complex process, low yield and high industrial manufacturing cost. In addition, solvents are usually added during the synthesis of the curing agent, which not only may harm the environment, but also is time-consuming and laborious to remove the solvents from the system, and the residual solvents may also affect the performance of the resin. Therefore, there is an urgent need in the art to develop a method for preparing an epoxy imine solid plastic material, which does not require a complex preparation process and does not require the addition of any solvent. SUMMARY

[0005] The present application aims to provide a method for preparing an epoxy imine solid plastic material by a one-step solvent-free method, to solve the technical problems of complex process, low yield, the need to add solvents and great harm to the environment in the synthesis of epoxy imine solid plastic.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0007] The present application provides a method for preparing an epoxy imine solid plastic material by a one-step solvent-free method, comprising the following steps:

[0008] (1) mixing polyaldehyde and epoxy resin to obtain a mixed solution;

[0009] (2) mixing aromatic polybasic primary amine curing agent into the mixed solution to obtain an epoxy imine prepolymer;

[0010] (3) placing the epoxy imine prepolymer in a mold for curing to obtain an epoxy imine solid plastic material.

[0011] Further, the polyaldehyde comprises one or more of terephthaldehyde, isophthaldehyde, glutaraldehyde, bis(4-formyl-2-methoxyphenyl) glutarate, bis(4-formyl-2-methoxyphenyl) terephthalate, 3,4',5-triformyl-1,1-biphenyl, and tris(4-formyl-2-methoxyphenyl) benzene-1,3,5-tricarboxylate.

[0012] Further, the epoxy resin comprises one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, and phenol aldehyde epoxy resin.

[0013] Further, the aromatic polyprimary amine curing agent comprises one or more of m-phenylenediamine, 4,4-diaminophenyl sulfone, and 4,4'-diaminodiphenyl methane.

[0014] Further, the molar ratio of the epoxy group of the epoxy resin to the aldehyde group of the polyaldehyde is 4:1 to 2:1.

[0015] Further, the molar ratio of the epoxy group of the epoxy resin to the amino group of the aromatic polyprimary amine curing agent is 4:3 to 1:1.

[0016] Further, the curing temperature is 160 to 210°C, and the curing time is 2 to 6 hours.

[0017] Further, in the step (1), the mixing temperature is 90 to 110°C, and the mixing time is 30 to 40 minutes.

[0018] Further, in the step (2), the mixing temperature is 100 to 130°C, and the mixing time is 15 to 30 minutes.

[0019] Advantages of the present application:

[0020] The method for preparing the epoxy imine solid plastic material provided by the present application is a one-step method without solvent, and the epoxy resin is cured in only one step, thereby avoiding yield loss caused by complex process and achieving a raw material utilization rate close to 100%. In addition, no solvent is used in the preparation process, thereby avoiding an additional step of removing the solvent, and the synthesis process is short and the method is simple. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The process flow chart of the one-step method for preparing the epoxy imine solid plastic material of the present application is shown in the figure. DETAILED DESCRIPTION

[0022] The present application provides a one-step method for preparing an epoxy imine solid plastic material without solvent, which comprises the following steps:

[0023] (1) mixing polyaldehyde and epoxy resin to obtain a mixed solution;

[0024] (2) mixing aromatic poly-primary amine curing agent into the mixed solution to obtain an epoxy imine prepolymer;

[0025] (3) curing the epoxy imine prepolymer in a mold to obtain an epoxy imine solid plastic material.

[0026] In the present application, the polyaldehyde comprises one or more of p-xylylene glycol, m-xylylene glycol, glutaric dialdehyde, bis(4-formyl-2-methoxyphenyl) glutarate, bis(4-formyl-2-methoxyphenyl) terephthalate, 3,4',5-triformyl-1,1-biphenyl, and tris(4-formyl-2-methoxyphenyl) benzene-1,3,5-tricarboxylate, preferably one or more of p-xylylene glycol, m-xylylene glycol and glutaric dialdehyde.

[0027] In the present application, the epoxy resin comprises one or more of bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic epoxy resin, preferably bisphenol A epoxy resin.

[0028] In the present application, the aromatic poly-primary amine curing agent comprises one or more of m-phenylenediamine, 4,4-diaminobenzene sulfone and 4,4'-diaminodiphenyl methane, preferably m-phenylenediamine.

[0029] In the present application, the molar ratio of epoxy groups of the epoxy resin to aldehyde groups of the polyaldehyde is 4:1 to 2:1, preferably 3:1.

[0030] In the present application, the molar ratio of epoxy groups of the epoxy resin to amino groups of the aromatic poly-primary amine curing agent is 4:3 to 1:1, preferably 4:3.

[0031] In the present application, the curing temperature is 160 to 210℃, preferably 180 to 200℃, and further preferably 190℃; and the curing time is 2 to 6h, preferably 3 to 5h, and further preferably 4h.

[0032] In the present application, the curing is performed in an oven or a hot press.

[0033] In the present application, in the step (1), the mixing temperature is 90 to 110℃, preferably 95 to 105℃, and further preferably 100℃; and the mixing time is 30 to 40min, preferably 30min.

[0034] In the present application, in the step (2), the mixing temperature is 100 to 130℃, preferably 120℃; and the mixing time is 15 to 30min, preferably 20min.

[0035] The technical solutions provided by the present application will be described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0036] Example 1

[0037] Into a 250 mL three-necked flask, add terephthaldehyde (2.68 g, 0.02 mol) and bisphenol A epoxy resin E51 (31 g, epoxy group amount 0.16 mol), stir at 90°C for 40 min to form a uniform and stable light yellow liquid; slowly add 4,4-diamino diphenyl sulfone (15 g, 0.06 mol) to the liquid, stir at 110°C for 30 min to obtain an imine prepolymer; pour the imine prepolymer into a mold, and cure in an oven at a temperature of 210°C for 3 hours to obtain an epoxy imine solid plastic material.

[0038] Example 2

[0039] Into a 250 mL three-necked flask, add terephthaldehyde (2.68 g, 0.02 mol) and bisphenol A epoxy resin E51 (31 g, epoxy group amount 0.16 mol), stir at 90°C for 40 min to form a uniform and stable light yellow liquid; slowly add 4,4-diamino diphenyl sulfone (15 g, 0.06 mol) to the liquid, stir at 110°C for 30 min to obtain an imine prepolymer; pour the imine prepolymer into a mold, and cure in an oven at a temperature of 210°C for 3 hours to obtain an epoxy imine solid plastic material.

[0040] Example 3

[0041] Into a 250 mL three-necked flask, add terephthaldehyde (2.68 g, 0.02 mol) and bisphenol A epoxy resin E51 (31 g, epoxy group amount 0.16 mol), stir at 90°C for 40 min to form a uniform and stable light yellow liquid; slowly add 4,4-diamino diphenyl sulfone (15 g, 0.06 mol) to the liquid, stir at 110°C for 30 min to obtain an imine prepolymer; pour the imine prepolymer into a mold, and cure in an oven at a temperature of 210°C for 3 hours to obtain an epoxy imine solid plastic material.

[0042] Comparative Example 1

[0043] In a 250 mL three-necked flask, 4,4-diaminobenzene sulfone (10 g, 0.04 mol) was dissolved in ethyl acetate solvent, heated to 50°C to form a uniform stable solution. Then bis(4-formaldehyde-2-methoxyphenyl) glutarate (8 g, 0.02 mol) was dissolved in a certain amount of ethyl acetate, slowly added into the three-necked flask and reacted for 6 h, and the product was filtered by recrystallization, washed with water, and dried in a vacuum oven at 60°C for 16 h to constant weight to obtain the imine curing agent (14 g, yield about 78%). The above imine curing agent and a small amount of 4,4-diaminobenzene sulfone (5 g, 0.02 mol) were added to bisphenol F epoxy resin (27 g, epoxy group content 0.16 mol), and stirred for 30 min until completely dissolved. Then the mixed resin mixture was poured into a mold and cured in an oven at a temperature of 180°C for 3 hours to obtain an epoxy imine solid plastic material.

[0044] The processes of Examples 1-3 and Comparative Example 1 were compared, and the results are shown in Table 1 below.

[0045] Table 1 Process comparison of Examples 1-3 and Comparative Example 1

[0046]

[0047]

[0048] As can be seen from the above examples, the present application provides a method for preparing an epoxy imine solid plastic material by a one-step solvent-free method. As can be seen from the comparison of Examples 1-3 and Comparative Example 1, the method of the present application only needs one step, the utilization rate of raw materials can reach 100%, and the yield is extremely high; and no solvent is added during the synthesis process, avoiding the additional step of removing the solvent, the synthesis time is short, and the process is simple and fast.

[0049] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A process for the preparation of epoxy imine solid plastic materials in one step without solvent, characterized in that, The method comprises the following steps: (1) mixing polyaldehyde and epoxy resin to obtain a mixed solution; (2) mixing aromatic poly-primary amine curing agent into the mixed solution to obtain an epoxy imine prepolymer; (3) curing the epoxy imine prepolymer in a mold to obtain an epoxy imine solid plastic material; The molar ratio of epoxy groups of the epoxy resin to aldehyde groups of the polyaldehyde is 4:1-2:1; In the step (1), the mixing temperature is 90-110℃, and the mixing time is 30-40 min; The curing temperature is 160-210℃, and the curing time is 2-6 h.

2. The process for the one-step solvent-free preparation of epoxy imine solid plastic materials according to claim 1, characterized in that, The polyaldehyde comprises one or more of p-phthaldehyde, m-phthaldehyde, glutaraldehyde, bis(4-aldehyde-2-methoxyphenyl) glutarate, bis(4-aldehyde-2-methoxyphenyl) terephthalate, 3,4',5-trialdehyde-1,1-biphenyl, and tris(4-aldehyde-2-methoxyphenyl) benzene-1,3,5-tricarboxylate.

3. The process for the solvent-free one-step preparation of epoxy imine solid plastic materials according to claim 1 or 2, characterized in that, The epoxy resin comprises one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, and phenolic epoxy resin.

4. The process for the one-step solvent-free preparation of epoxy imine solid plastic materials according to claim 3, characterized in that, The aromatic poly-primary amine curing agent comprises one or more of m-phenylenediamine, 4,4-diamino phenyl sulfone, and 4,4'-diamino diphenyl methane.

5. The process for the one-step solvent-free preparation of epoxy imine solid plastic materials according to claim 4, characterized in that, The molar ratio of epoxy groups of the epoxy resin to amino groups of the aromatic poly-primary amine curing agent is 4:3-1:

1.

6. The process for the one-step solvent-free preparation of epoxy imine solid plastic materials according to claim 5, characterized in that, In the step (2), the mixing temperature is 100-130℃, and the mixing time is 15-30 min.

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