A flexible aliphatic epoxy oligomer and a method for preparing the same

Abstract

The application discloses a flexible aliphatic cyclic epoxy oligomer and a preparation method thereof, and comprises a compound I and a compound II. The preparation method of the compound I comprises the following steps: after TTA21, adipic acid, a solvent and a catalyst are added into a reactor, oil bath heating is carried out, the reaction temperature is controlled to be 120±5 DEG C, and stirring reaction is carried out for 3-4 h; after the reaction is qualified, the reaction liquid is cooled to below 35 DEG C, and the reaction liquid is washed with deionized water twice, each time for 30 min; after the organic phase after washing is subjected to solvent removal under reduced pressure, the target product is obtained. The application has the beneficial effect that the technical scheme adopts a method of introducing a flexible chain end to toughen, so that the crosslinking network in the epoxy resin has a more compact effect; after an organic compound of the flexible chain and an epoxy group in the epoxy resin are subjected to chemical reaction, the flexible chain segment is gradually introduced into the epoxy main chain, so that a new epoxy resin is prepared; the epoxy resin has high strength and good adhesion.

Description

Technical Field

[0001] This invention relates to the field of epoxy oligomer preparation technology, and in particular to a flexible alicyclic epoxy oligomer and its preparation method. Background Technology

[0002] Alicyclic epoxy resins are compounds containing two or more alicyclic epoxy groups, which are formed by oxidation. Alicyclic epoxy resins contain cyclohexyl groups, do not contain double bonds, and the epoxy groups in the molecular structure are directly attached to cyclohexane. Therefore, they have relatively stable chemical properties and have advantages such as good weather resistance, excellent electrical insulation properties, high heat resistance, and good processability.

[0003] Alicyclic epoxy resins have promising applications in the field of electronic packaging due to their excellent processability, dielectric properties, thermal stability, and adhesion. With the development of research and applications towards thinner and more flexible electronic devices, higher requirements are being placed on the properties of thin-film encapsulation materials, including high-temperature resistance, thermal shock resistance, flexibility, high tear resistance, gas permeability, and light transmittance.

[0004] Alicyclic epoxy resins have a rigid structure and high crosslinking density, which makes the cured encapsulation material brittle and prone to breakage. Therefore, toughening modification of alicyclic epoxy resins is a key task to expand their application range.

[0005] Over the past few decades, significant efforts have been made in toughening epoxy resins, but many problems remain. For example, rubber elastomers and core-shell polymers reduce the modulus and heat resistance of epoxy resins while toughening them; block copolymers typically reduce the strength of epoxy resins while toughening them; liquid crystal polymers can significantly improve toughness while maintaining modulus and heat resistance, but their weak solubility, compatibility, and poor flowability in epoxy resins make them difficult to process; nanomaterials tend to agglomerate during toughening, making it difficult to disperse uniformly in the matrix, resulting in unstable product performance. Therefore, addressing these shortcomings and deficiencies in epoxy resin toughening design and seeking composite materials with superior overall performance has become a major focus of epoxy resin toughening research. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems by designing a flexible alicyclic epoxy oligomer and its preparation method.

[0007] The technical solution of the present invention to achieve the above objectives is a flexible alicyclic epoxy oligomer and its preparation method, comprising compound I and compound II, wherein the structural formulas of compound I and compound II are as follows:

[0008]

[0009] As a further description of this technical solution, the preparation method of compound I includes the following steps: after adding TTA21, adipic acid, solvent and catalyst to the reactor, heating in an oil bath, controlling the reaction temperature at 120±5℃, and stirring the reaction for 3-4 hours;

[0010] After the reaction is successful, the reaction solution is cooled to below 35°C and washed twice with deionized water for 30 minutes each time. After washing, the organic phase is desolvated under reduced pressure to remove the solvent and obtain the target product.

[0011] As a further description of this technical solution, the preparation method of compound II includes the following steps: after adding TTA21, adipic acid, solvent and catalyst to the reactor, heating in an oil bath, controlling the reaction temperature at 120±5℃, and stirring the reaction for 5-8 hours;

[0012] After the reaction is successful, the reaction solution is cooled to below 35°C and washed twice with deionized water for 30 minutes each time. After washing, the organic phase is desolvated under reduced pressure to remove the solvent and obtain the target product.

[0013] As a further description of this technical solution, the catalyst includes triphenylphosphine or tributylphosphine.

[0014] As a further description of this technical solution, in the preparation method of compound I, the molar ratio of the catalyst to adipic acid is 0.003-0.01:1.

[0015] As a further description of this technical solution, in the preparation method of compound II, the molar ratio of catalyst to adipic acid is 0.005-0.02:1.

[0016] As a further description of this technical solution, in the preparation method of compound I, the molar ratio of TTA21 to adipic acid is 2.05-2.25:1.

[0017] As a further description of this technical solution, in the preparation method of compound II, the molar ratio of TTA21 to adipic acid is 4.10-4.35:1.

[0018] Its beneficial effect is that the technical solution adopts the method of introducing flexible chain ends to toughen the epoxy resin, so that the cross-linking network in the epoxy resin has a tighter effect. After the organic compound of the flexible chain reacts with the epoxy group in the epoxy resin, it will gradually introduce the flexible chain segment into the epoxy main chain, thereby creating a new epoxy resin. This epoxy resin not only has high strength, but also has good adhesion. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the GPC detection results of compound II of the present invention;

[0020] Figure 2 This is the H-NMR spectrum of compound II of the present invention. Detailed Implementation

[0021] The alicyclic epoxy oligomer of the present invention uses 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate (TTA21) as the main raw material, and introduces adipic acid as a flexible chain end into the resin structure to achieve the effect of toughening modification.

[0022] The present invention will now be described in detail with reference to the accompanying drawings. A flexible alicyclic epoxy oligomer includes compound I and compound II, the structural formulas of which are as follows:

[0023]

[0024] The preparation method of compound I includes the following steps: after adding TTA21, adipic acid, solvent and catalyst to the reactor, heating in an oil bath, controlling the reaction temperature at 120±5℃, and stirring the reaction for 3-4 hours;

[0025] After the reaction is successful, the reaction solution is cooled to below 35°C and washed twice with deionized water for 30 minutes each time. After washing, the organic phase is desolvated under reduced pressure to remove the solvent and obtain the target product.

[0026] In the preparation method of compound I, the molar ratio of the catalyst to adipic acid is 0.003-0.01:1, and in the preparation method of compound I, the molar ratio of TTA21 to adipic acid is 2.05-2.25:1.

[0027] The preparation method of compound II includes the following steps: after adding TTA21, adipic acid, solvent and catalyst to the reactor, heating in an oil bath, controlling the reaction temperature at 120±5℃, and stirring the reaction for 5-8 hours;

[0028] After the reaction is qualified, the reaction solution is cooled to below 35°C and washed twice with deionized water for 30 min each time. After washing, the organic phase is desolvated under reduced pressure to remove the solvent and obtain the target product. In the preparation method of compound II, the molar ratio of catalyst to adipic acid is 0.005-0.02:1, and in the preparation method of compound II, the molar ratio of TTA21 to adipic acid is 4.10-4.35:1.

[0029] The catalyst includes triphenylphosphine or tributylphosphine.

[0030] This invention provides a toughened modified alicyclic epoxy oligomer and its preparation method. The epoxy oligomer has the structure shown in Formula I and II, which greatly increases its toughness while maintaining the high Tg point of TTA21 resin UV-cured product.

[0031] The present invention will be described in detail below with reference to embodiments:

[0032] The preparation method of compound I as the target product is as follows:

[0033] Example 1: 126g TTA21, 34.3g adipic acid, 0.31g triphenylphosphine, and 1000g cyclohexanone were added to a 2000ml dry three-necked round-bottom flask equipped with a reflux condenser. The flask was placed in an oil bath and heated to 120°C. The mixture was stirred for 3.5 hours. The acid value of the reaction solution was measured. After the reaction was deemed satisfactory, the solution was washed twice with 150g*2 deionized water for 30 minutes each time. The organic phase was separated and dissolved under reduced pressure to obtain product 1158.6g. The product was a viscous, transparent liquid with a yield of 98.9%, an epoxy equivalent of 168, and a viscosity (25°C) of 2360 cps.

[0034] Example 2: Other conditions were the same as in Example 1, except that the amount of adipic acid was changed to 33.2g and the amount of triphenylphosphine was changed to 0.35g. Product 2 was obtained, a viscous transparent liquid with a yield of 99.1%, an epoxy equivalent of 157, and a viscosity (25°C) of 1950cps.

[0035] The preparation method of compound II as the target product is as follows:

[0036] Example 3: 124.6g TTA21, 17.2g adipic acid, 0.31g triphenylphosphine, and 1000g cyclohexanone were added to a 2000ml dry three-necked round-bottom flask equipped with a reflux condenser. The flask was placed in an oil bath and heated to 120℃. The reaction was stirred for 6 hours. The acid value of the reaction solution was measured. After the reaction was deemed satisfactory, the solution was washed twice with 150g*2 deionized water for 30 minutes each time. The organic phase was separated and dissolved under reduced pressure to obtain product 3, 137.8g; yield 97.2%, epoxy equivalent 235, viscosity (75℃) 18500cps.

[0037] Experimental Example 4 was conducted under the same conditions as Example 3, except that the amount of TTA21 added was changed to 129.5g. Product 4 was obtained, weighing 143.0g, in a paste-like liquid form with a yield of 97.5%, an epoxy equivalent of 226, and a viscosity (75°C) of 17400cps.

[0038] The cured product performance data of Compound I and Compound II are shown in Table 1. The test data show that the toughness of the cured product of Compound I is better than that of the cured product of TTA21, and its Tg point is lower than that of the cured product of TTA21 but higher than that of the cured product of TTA26. The Tg point of the cured product of Compound II is close to that of the cured product of TTA21, and its toughness is comparable to that of the cured product of TTA26. Compound II combines the advantages of TTA21 and TTA26 in terms of Tg point and toughness, respectively, and is a high-performance resin. Overall, the cured products of Compound I and Compound II have good performance and can replace TTA21 and TTA26 in some application scenarios.

[0039] Table 1. Performance Data of Cured Products

[0040]

[0041] This technical solution employs a method of introducing flexible chain ends to toughen the epoxy resin, resulting in a more compact cross-linked network. After the flexible chain organic compound reacts chemically with the epoxy groups in the epoxy resin, it gradually introduces the flexible chain segments into the epoxy backbone, thereby creating a new epoxy resin. This epoxy resin not only has high strength but also excellent adhesion.

[0042] The above technical solutions only embody the preferred technical solutions of the present invention. Any modifications that may be made by those skilled in the art to certain parts thereof embody the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. A flexible alicyclic epoxy oligomer, characterized in that, Including compound I and compound II, the structural formulas of compound I and compound II are as follows: Compound I, Compound II.

2. The method for preparing a flexible alicyclic epoxy oligomer according to claim 1, characterized in that, The preparation method of compound I includes the following steps: after adding TTA21, adipic acid, solvent and catalyst to the reactor, heating in an oil bath, controlling the reaction temperature at 120±5℃, and stirring the reaction for 3-4 hours; After the reaction is qualified, the reaction solution is cooled to below 35°C and washed twice with deionized water for 30 minutes each time. After washing, the organic phase is desolvated under reduced pressure to remove the solvent and obtain the target product. The catalyst is triphenylphosphine; The molar ratio of TTA21 to adipic acid is 2.05-2.25:1; The preparation method of compound II includes the following steps: after adding TTA21, adipic acid, solvent and catalyst to the reactor, heating in an oil bath, controlling the reaction temperature at 120±5℃, and stirring the reaction for 5-8 hours; After the reaction is qualified, the reaction solution is cooled to below 35°C and washed twice with deionized water for 30 minutes each time. After washing, the organic phase is desolvated under reduced pressure to remove the solvent and obtain the target product. The catalyst is triphenylphosphine; The molar ratio of TTA21 to adipic acid is 4.10-4.35:

1.

3. The method for preparing a flexible alicyclic epoxy oligomer according to claim 2, characterized in that, In the preparation method of compound I, the molar ratio of the catalyst to adipic acid is 0.003-0.01:

1.

4. The method for preparing a flexible alicyclic epoxy oligomer according to claim 2, characterized in that, In the preparation method of compound II, the molar ratio of catalyst to adipic acid is 0.005-0.02:1.

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