Epoxy resin composition with long operation time and preparation method thereof

Abstract

The invention discloses an epoxy resin composition with long operation time and a preparation method thereof, the epoxy resin composition comprises: A) a component at least comprising a polyfunctional epoxy resin and 9, 10-epoxy-1, 5-cyclododecadiene, and B) a component at least comprising a polyfunctional epoxy resin and 9, 10-epoxy-1, 5-cyclododecadiene; and the component B) at least comprises a bifunctional alicyclic organic amine. The epoxy resin composition prepared by the invention can obviously prolong the operation time of the composition and improve the phenomenon of reaction heat release concentration, has high toughness, high heat resistance and mechanical properties, and can be used for preparing epoxy resin materials and composite materials thereof with excellent comprehensive properties.

Description

Technical Field

[0001] The invention belongs to the field of epoxy resin materials, and specifically relates to an epoxy resin composition with a long operating time and a preparation method thereof. Background Art

[0002] Epoxy resins are widely used in aerospace, new energy, transportation, construction, sports and leisure, composite materials and other fields due to their good processing properties, excellent heat resistance, corrosion resistance and mechanical properties. Aliphatic or alicyclic organic amines are widely used as curing agents for epoxy resins due to their high reactivity, which can usually achieve rapid curing and efficient molding of materials. However, the high room temperature reactivity usually also results in insufficient operating time and significant heat concentration, which is particularly unfavorable for the preparation of large-sized parts, resulting in problems such as reduced toughness and easy cracking of products.

[0003] Invention patent CN102105441B discloses a blend comprising epoxy resin and a mixture of amine and guanidine derivatives. The introduction of guanidine derivatives into the amine curing agent significantly prolongs the gel time of the epoxy resin and increases the shelf life. However, the guanidine derivatives used in the invention reduce the viscosity of the epoxy resin system and do not have an effect on improving toughness.

[0004] Therefore, there is an urgent need to develop a new epoxy resin composition in the art that can meet both the low viscosity and long operating time required by the process and the high toughness required by the application. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention provides an epoxy resin composition and a preparation method thereof. By introducing 9,10-epoxy-1,5-cyclododecadiene into the epoxy resin composition, the operation time of the composition can be significantly improved, the phenomenon of reaction exothermic concentration can be improved, and the composition has high toughness, high heat resistance and mechanical properties.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides an epoxy resin composition with a long working time, comprising:

[0008] A) a component comprising at least one multifunctional epoxy resin and 9,10-epoxy-1,5-cyclododecadiene;

[0009] B) component comprises at least one difunctional alicyclic organic amine.

[0010] In the present invention, the mass ratio of the A) component to the B) component is 100:(15-35), preferably 100:(25-30).

[0011] In the present invention, the mass percentage composition of the component A) includes: 71-99% of multifunctional epoxy resin, 1-29% of 9,10-epoxy-1,5-cyclododecadiene;

[0012] Preferably, the polyfunctional epoxy resin is 81-95% and the 9,10-epoxy-1,5-cyclododecadiene is 5-19%.

[0013] In the component A) of the present invention, the functionality of the multifunctional epoxy resin is ≥ 2, preferably 2-3;

[0014] In some specific examples, the multifunctional epoxy resin is selected from a combination of one or more of bisphenol A glycidyl ether, bisphenol F glycidyl ether, glycidyl amine, alicyclic glycidyl ether, 1,4-butanediol diglycidyl ether, alkyl glycidyl ether, and benzyl glycidyl ether, preferably bisphenol A glycidyl ether and bisphenol F glycidyl ether.

[0015] In the component A) of the present invention, the 9,10-epoxy-1,5-cyclododecadiene (EPO), CAS No. 943-93-1, has the following molecular structure:

[0016] In the component B) of the present invention, the difunctional alicyclic organic amine is selected from diaminodicyclohexylmethane, isophoronediamine, methylcyclohexanediamine, dimethyldiaminodicyclohexylmethane, 1,3-cyclohexanedimethylamine, or a combination of one or more thereof, preferably diaminodicyclohexylmethane or isophoronediamine.

[0017] The epoxy composition A) of the present invention may optionally contain an auxiliary agent;

[0018] The additives include but are not limited to diluents, defoamers, leveling agents, toughening agents, coupling agents, wetting and dispersing agents, flame retardants, plasticizers and inorganic fillers. Adding additives to the composite material is a routine operation in the art, and the present invention has no special requirements for the type and amount thereof. The technicians can screen the type of additives and determine the amount of additives in the epoxy resin composition according to actual needs based on the methods disclosed in the prior art.

[0019] The present invention also provides a method for preparing the above-mentioned epoxy resin composition with a long operating time, comprising the following steps:

[0020] 1) A) Preparation of components: at least one multifunctional epoxy resin, 9,10-epoxy-1,5-cyclododecadiene, and optional auxiliary agents are mixed and stirred uniformly at a mixing temperature of 20-30° C.;

[0021] 2) B) component preparation: mixing and stirring at least one difunctional organic amine uniformly;

[0022] 3) Component A) and component B) are mixed uniformly, and then vacuum degassing is performed to obtain an epoxy resin composition with a long working time.

[0023] In the present invention, the vacuum degassing in step 3) has a pressure of -(0.01-0.02)MPa, a temperature of 20-30°C, and a time of 3-5min.

[0024] Compared with the prior art, the present invention has the following positive effects:

[0025] (1) Significantly improve the operating time of epoxy compositions: 9,10-epoxy-1,5-cyclododecadiene has a good dilution effect on epoxy resins. In addition, its epoxy group has extremely low reactivity at room temperature. Its introduction into epoxy resin compositions can significantly improve the operating time of the compositions (the operating time can be extended by more than 2 times) and improve the phenomenon of concentrated reaction exothermicity.

[0026] (2) Significantly improve the toughness of epoxy resin compositions: 9,10-epoxy-1,5-cyclododecadiene has good compatibility with epoxy resin. On the one hand, the macrocyclic structure increases the free volume and improves the toughness of the resin. On the other hand, the rigid twelve-membered macrocyclic structure forms an interpenetrating structure with the epoxy cross-linking network, which enables the resin system to maintain strength, modulus and heat resistance. DETAILED DESCRIPTION

[0027] The present invention is further described by means of specific embodiments. The embodiments of the present invention are only used as illustrations of the present invention and do not limit the scope of the present invention.

[0028] 1. The main raw materials and their sources in the examples are shown in Table 1.

[0029] Table 1 Raw materials and sources

[0030]

[0031] Other raw materials not specified in Table 1 were purchased from the market.

[0032] 2. Performance test method:

[0033] Viscosity test method: Tested using Brookfield DV-II rotational viscometer;

[0034] Gel time test method: hot plate method, resin thickness 1mm, stirring wire drawing method to determine the gel point;

[0035] Mechanical properties test method: The epoxy resin composition was cured at 80°C / 6h to prepare mechanical properties test specimens, which were tested using a universal material testing machine from Instron, USA; the mechanical properties of the resin matrix material were tested in accordance with standard GB / T 2567; the fracture toughness KIC test was completed in accordance with ASTM D 5045-99;

[0036] Heat deformation temperature HDT: heating rate: 2℃ / min, test standard: ISO-306;

[0037] Exothermic peak temperature test: 100g resin, 25℃ circulating water bath, paperless recorder to record temperature changes.

[0038] Examples 1-4

[0039] The long-operation-time epoxy resin composition is prepared (the types and amounts of the raw materials in the compositions of Examples 1-4 are shown in Table 1), and the steps are as follows:

[0040] 1) A) Preparation of components: uniformly mixing at least one multifunctional epoxy resin, EPO and defoamer by mechanical stirring at room temperature;

[0041] 2) Preparation of component B): uniformly mixing at least one multifunctional organic amine by mechanical stirring at room temperature;

[0042] 3) mixing component A) and component B) uniformly, mixing uniformly at room temperature by mechanical stirring, and then vacuum degassing for 3-5 minutes at room temperature (20-30° C.) at a pressure of -0.01 MPa to obtain an epoxy resin composition with a long operating time;

[0043] 4) The epoxy resin composition was slowly poured into a stainless steel mold and cured at 80° C. for 6 h to prepare epoxy resin cured product specimens of Examples 1-4 for performance testing. The results are shown in Table 2.

[0044] Comparative Example 1

[0045] The method of Example 1 was used with the exception that: A) the raw material EPO was not added to the component, and other operations and conditions remained unchanged to obtain an epoxy resin composition, which was prepared into cured specimens for performance testing. The results are shown in Table 2.

[0046] Comparative Example 2

[0047] The method of Example 1 was followed except that: A) EPO was replaced with CDT in the component, and other operations and conditions remained unchanged to obtain an epoxy resin composition, which was prepared into cured specimens for performance testing. The results are shown in Table 2.

[0048] Table 1 Types and amounts of raw materials in the composition of the embodiment

[0049]

[0050] Table 2 Performance test results of epoxy resin compositions of examples and comparative examples

[0051]

[0052] By comparing the performance data of the examples and the comparative examples in Table 2, it can be seen that, first, the viscosity of the examples is significantly reduced compared with the comparative example 1 due to the addition of the EPO component, and the operation time is significantly prolonged, the exothermic peak temperature is significantly reduced, and the time to reach the exothermic peak temperature is significantly delayed, thus proving that the introduction of EPO improves the exothermic concentration phenomenon of the reaction; second, although the introduction of the similar cyclic structure molecule CDT without epoxy groups in the comparative example 2 reduces the exothermic temperature and prolongs the operation time, its mechanical properties, fracture toughness, and heat resistance are significantly reduced compared with the examples, further illustrating that the EPO component can maintain the toughness, mechanical properties, and heat resistance of the epoxy resin while prolonging the operation time compared with other inert cyclic molecules.

Claims

1. A long working time epoxy resin composition, characterized in that Include: A) a component comprising at least one multifunctional epoxy resin and 9,10-epoxy-1,5-cyclododecadiene; B) component comprises at least one difunctional alicyclic organic amine.

2. The composition according to claim 1, characterized in that The mass ratio of the A) component to the B) component is 100:(15-35), preferably 100:(25-30).

3. The composition according to claim 1 or 2, characterized in that The mass percentage composition of the component A) includes: 71-99% of multifunctional epoxy resin and 1-29% of 9,10-epoxy-1,5-cyclododecadiene; Preferably, the polyfunctional epoxy resin is 81-95% and the 9,10-epoxy-1,5-cyclododecadiene is 5-19%.

4. The composition according to any one of claims 1 to 3, characterized in that In component A), the functionality of the multifunctional epoxy resin is ≥2, preferably 2-3.

5. The composition according to any one of claims 1 to 4, characterized in that The multifunctional epoxy resin is selected from one or more combinations of bisphenol A glycidyl ether, bisphenol F glycidyl ether, glycidyl amine, alicyclic glycidyl ether, 1,4-butanediol diglycidyl ether, alkyl glycidyl ether, and benzyl glycidyl ether, preferably bisphenol A glycidyl ether and bisphenol F glycidyl ether.

6. The composition according to any one of claims 1 to 5, characterized in that The difunctional alicyclic organic amine is selected from one or more combinations of diaminodicyclohexylmethane, isophoronediamine, methylcyclohexanediamine, dimethyldiaminodicyclohexylmethane, and 1,3-cyclohexanedimethylamine, preferably diaminodicyclohexylmethane and isophoronediamine.

7. The composition according to any one of claims 1 to 6, characterized in that The component A) may optionally contain an auxiliary agent; The auxiliary agents include, but are not limited to, diluents, defoamers, leveling agents, toughening agents, coupling agents, wetting and dispersing agents, flame retardants, plasticizers and inorganic fillers.

8. A method for preparing the long-operating-time epoxy resin composition according to any one of claims 1 to 7, characterized in that the steps include: 1) A) Preparation of components: at least one multifunctional epoxy resin, 9,10-epoxy-1,5-cyclododecadiene, and optional auxiliary agents are mixed and stirred uniformly at a mixing temperature of 20-30° C.; 2) B) component preparation: mixing and stirring at least one difunctional organic amine uniformly; 3) Component A) and component B) are mixed uniformly, and then vacuum degassing is performed to obtain an epoxy resin composition with a long working time.

9. The preparation method according to claim 8, characterized in that: Step 3) The vacuum degassing has a pressure of -(0.01-0.02) MPa, a temperature of 20-30°C, and a time of 3-5 min.

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