CN111410817A - Epoxy resin composition, preparation method and application thereof in hot-melt prepreg - Google Patents

Abstract

The invention of the invention relates to an epoxy resin composition, a preparation method and its application in hot-melt prepreg. According to the requirements of the composite material for curing temperature, reactivity, processability and appearance characteristics, a medium-temperature curing reaction is designed to be gentle. The main resin of the hot-melt epoxy resin and the proportion of each component, the main epoxy resin, thermoplastic resin, curing agent and accelerator are prepared under certain conditions to obtain an epoxy resin composition that meets the requirements for use; The hot-melt adhesive film is coated with the oxygen resin system, and then compounded with reinforcing fibers or fabrics to obtain a hot-melt prepreg.

Description

Epoxy resin composition, preparation method and application thereof in hot-melt prepreg

technical field

The invention belongs to the technical field of manufacturing hot-melt prepregs for structural composite materials, and particularly relates to an epoxy resin composition, a preparation method and its application in hot-melt prepregs.

Background technique

Resin matrix composites have been widely used in aerospace, rail transit and other fields due to their light weight and high strength. Reaching 210mm, this kind of large shell and variable thickness structural parts put forward more stringent requirements for the resin matrix and the forming process. For example, the curing process is relatively gentle but must be cured at 130 °C, and the surface of the formed product has no holes, and no additional processing is required. spraying etc.

The existing medium-temperature curing systems are mostly latent resin systems, and 1,1-dimethyl-3-phenylurea is used as the accelerator. When the temperature is in the range of 90-130 °C, the latent curing agent is rapidly excited and the reaction is released. Larger heat, multiple thermal insulation steps need to be artificially set when forming large-scale and large-thickness composite materials, but the consistency of product quality is still not guaranteed. Moreover, the appearance quality of the composite products manufactured by the current resin system often has tiny voids, which requires a subsequent spraying process. Due to the poor bonding between the coating system and the composite material interface, there is a risk of peeling off at any time.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned defects of the prior art, and to provide a medium-temperature curing and low exothermic epoxy resin composition.

Another object of the present invention is to provide a preparation method of a medium-temperature curing and low exothermic hot-melt epoxy resin composition.

Still another object of the present invention is to provide a hot-melt prepreg comprising the hot-melt epoxy resin composition.

The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

The technical scheme of the present invention is: according to the requirements of the composite material for curing temperature, reactivity, manufacturability and appearance characteristics, the main resin and the proportion of each component of the hot-melt epoxy resin with gentle curing reaction at medium temperature are designed, and the main epoxy resin is , thermoplastic resin, curing agent and accelerator, under certain conditions, a hot-melt epoxy resin that meets the requirements of use can be prepared. The hot-melt adhesive film is coated with the above epoxy resin system, and then compounded with reinforcing fibers or fabrics to obtain a hot-melt prepreg.

The concrete method of the present invention is:

(1) Dissolving the multifunctional epoxy resin and thermoplastic resin in the main epoxy resin at 100-150° C., stirring for 30-120 minutes at a temperature until both are transparent, and obtaining component A;

(2) adding the low-viscosity epoxy resin in the main epoxy resin, the curing agent and the accelerator in proportion to premix, and grinding by three-roll grinding equipment for 20-40min to obtain component B;

(3) The component A in (1) and the component B in (2) are blended at 60-90° C. for 10-40 minutes to obtain a medium-temperature curing and low exothermic hot-melt epoxy resin composition.

Specifically, the mass percentages of the main epoxy resin, thermoplastic resin, curing agent, and accelerator are respectively 74%-92%: 4%-16%: 2.3%-8.6%: 0.8%-4.4%, and The sum of the percentages of the above components is 100%. When each component is proportioned according to the above ratio, it can not only ensure that the resin system is completely cured in a medium temperature range, but also ensure that the surface of the composite product prepared with the above resin has no holes and no need to spray.

Wherein, the main epoxy resin is a mixture of low viscosity epoxy resin and multifunctional epoxy resin, preferably, the mass ratio of low viscosity epoxy resin to multifunctional epoxy resin is 10:90-90:10;

The low-viscosity epoxy resin is one of bisphenol A glycidyl ether (DYD128, Yueyang Petrochemical Resin Factory) and bisphenol F glycidyl ether (830s, Wuxi Resin Factory) or a combination thereof;

The multifunctional epoxy resins are glycidylamine (AG-80, commercially available), novolac epoxy resin (638s, commercially available), multifunctional glycidyl ester alicyclic epoxy resin (TDE-85, commercially available) ), or a combination thereof;

The thermoplastic resin is a thermoplastic that can be dissolved in an epoxy resin, preferably one or a combination of polyvinyl formal, polyvinyl butyral, and polyethersulfone. The appearance of the subsequent composite products is smooth without holes;

Described curing agent is a kind of or its combination of dicyandiamide (Dicy, commercially available) or modified dicyandiamide (HT2833, commercially available);

The accelerator is a composition with the following chemical structures IA (Ecure20, commercially available) and IB (UR800, commercially available). Preferably, the mass ratio of the IA:IB composition is 1:0.2 to 1:1.0, that is, It is guaranteed that the hot melt epoxy resin system can be cured in the medium temperature range, and at the same time, due to the special chemical structure, the reaction exotherm is gentle.

Using the above-mentioned hot-melt epoxy resin composition as a resin matrix to coat a hot-melt adhesive film, and then compound it with reinforcing fibers or fabrics to prepare a hot-melt prepreg. Wherein, the percentage mass content of the resin matrix in the hot-melt prepreg is 30% to 40%.

The application of the medium-temperature-cured hot-melt epoxy resin composition and the hot-melt prepreg prepared according to the above method in the preparation of resin-based composite materials also belongs to the protection scope of the present invention.

Beneficial effects created by the present invention:

(1) The hot-melt epoxy resin composition provided by the present invention adopts two kinds of accelerators, aromatic urea (IA) and alicyclic urea (IB), to be mixed, wherein, the IA aromatic urea contains electron-withdrawing halogen atoms. Induction effect, which makes the catalytic activity lower than that of 1,1-dimethyl-3-phenylurea in the presence of dicyandiamide; IB is an alicyclic urea, which cures more gently and can impart More storage periods of prepreg can ensure that the resin system can be cured at 90-130 ° C, and can ensure low reaction heat and smooth curing. Oxygen resin system.

(2) The hot-melt epoxy resin composition provided by the present invention is dissolved and modified by a specific thermoplastic resin, has good adhesion at room temperature, and the surface appearance of the composite product prepared by using the hot-melt epoxy resin composition Fullness and no holes.

(3) The hot-melt epoxy resin composition and its prepreg provided by the present invention have been used in large and super-sized composite products, and the surface of the product can meet the index requirements without secondary spraying.

Detailed ways

It should be noted that the embodiments of the present invention and the features of the embodiments may be combined with each other under the condition of no conflict.

Example 1

Step (1): 17.1 kg of the polyfunctional glycidyl ester alicyclic epoxy resin (TDE-85, Tianjin Jingdong Chemical Co., Ltd.) in the main epoxy resin was heated to 120° C. to melt, and 1 kg of polyvinyl butyral was added. Aldehyde, heat preservation for 30-90min to completely dissolved and transparent state to obtain component A;

Step (2): 3.1kg of low-viscosity epoxy resin bisphenol F glycidyl ether (830s, Shanghai Synthetic Resin Factory) in the main epoxy resin and 1kg of curing agent (modified dicyandiamide, HT2833, commercially available), 0.24kg of accelerator (IA:IB=5:1) was added in proportion to premix, and ground for 40min by three-roll grinding equipment to obtain component B;

Step (3): The component A in (1) and the component B in (2) are blended at 70° C. for 30 minutes to obtain a medium-temperature curing and low exothermic hot-melt epoxy resin composition.

The hot-melt epoxy resin composition was used as the resin matrix to coat the hot-melt adhesive film, and then compounded with T300 carbon fiber to obtain a hot-melt prepreg, and the mass percentage of the resin matrix was controlled to be 36%.

A DSC (DSC2500, TA company) was used to scan at a heating rate of 10°C/min, and the reaction exotherm was 150 J/g. The composite material product prepared by using the above-mentioned hot-melt epoxy resin composition and its prepreg has no holes on the surface, smooth appearance and good molding quality. The prepreg storage period is 60 days.

Example 2

Step (1): 17.5kg of polyfunctional glycidyl ester alicyclic epoxy resin (TDE-85, Tianjin Jingdong Chemical Co., Ltd.) in the main epoxy resin was heated to 120° C. to melt, and 2kg of polyvinyl butyral was added. Aldehyde, heat preservation for 30-90min to completely dissolved and transparent state to obtain component A;

Step (2): 3kg parts of low-viscosity epoxy resin bisphenol F glycidyl ether (830s, Shanghai Synthetic Resin Factory) in the main epoxy resin, 1.6kg parts of curing agent (dicyandiamide, commercially available), accelerator (IA:IB=4:1) 0.4kg was added to the premix in proportion, and ground for 40min by three-roll grinding equipment to obtain component B;

Step (3): The component A in (1) and the component B in (2) are blended at 70° C. for 30 minutes to obtain a medium-temperature curing and low exothermic hot-melt epoxy resin composition.

The hot-melt epoxy resin composition was used as the resin matrix to coat the hot-melt adhesive film, and then compounded with EW400 glass fiber to obtain a hot-melt prepreg, and the mass percentage of the resin matrix was controlled to be 36%.

A DSC (DSC2500, TA company) was used to scan at a heating rate of 10°C/min, and the reaction exotherm was 170 J/g. The composite material product prepared by using the above-mentioned hot-melt epoxy resin composition and its prepreg has no holes on the surface, smooth appearance and good molding quality. The prepreg storage period is 60 days.

Example 3

Step (1): 18kg of the polyfunctional glycidyl ester alicyclic epoxy resin (TDE-85, Tianjin Jingdong Chemical Co., Ltd.) in the main epoxy resin was heated to 120°C to melt, and 1kg of polyvinyl butyral was added. , heat preservation for 30-90min to completely dissolved and transparent state to obtain component A;

Step (2): 3kg of low-viscosity epoxy resin bisphenol F glycidyl ether (830s, Shanghai Synthetic Resin Factory) in the main epoxy resin, 2kg of curing agent (dicyandiamide, commercially available), accelerator (IA: IB=3:1) 0.48kg was added in proportion to premix, and ground for 40min by three-roll grinding equipment to obtain component B;

Step (3): The component A in (1) and the component B in (2) are blended at 70° C. for 30 minutes to obtain a medium-temperature curing and low exothermic hot-melt epoxy resin composition.

The hot-melt epoxy resin composition was used as the resin matrix to coat the hot-melt adhesive film, and then compounded with T700 carbon fiber to obtain a molten prepreg, and the mass percentage of the resin matrix was controlled to be 35%.

DSC (DSC2500, TA company) was used to scan at a heating rate of 10°C/min, and the reaction exotherm was 175 J/g. The composite material product prepared by using the above-mentioned hot-melt epoxy resin composition and its prepreg has no holes on the surface, smooth appearance and good molding quality. The prepreg storage period is 50 days.

Example 4

Step (1): 16.5kg of the polyfunctional glycidyl ester alicyclic epoxy resin (TDE-85, Tianjin Jingdong Chemical Co., Ltd.) in the main epoxy resin was heated to 120°C to melt, 4kg of polyethersulfone was added, and the temperature was kept warm. 30-90min to completely dissolved and transparent state to obtain component A;

Step (2): 3kg of low-viscosity epoxy resin bisphenol F glycidyl ether (830s, Shanghai Synthetic Resin Factory) in the main epoxy resin, 1.25kg of curing agent (dicyandiamide, commercially available), accelerator (IA : IB=2:1) 0.65kg was added in proportion to pre-mix, and ground for 40min by three-roll grinding equipment to obtain component B;

Step (3): The component A in (1) and the component B in (2) are blended at 70° C. for 30 minutes to obtain a medium-temperature curing and low exothermic hot-melt epoxy resin composition.

The hot-melt epoxy resin composition was used as the resin matrix to coat the hot-melt adhesive film, and then compounded with T800 carbon fiber to obtain a hot-melt prepreg, and the mass percentage of the resin matrix was controlled to be 34%.

DSC (DSC2500, TA company) was used to scan at a heating rate of 10°C/min, and the reaction exotherm was 180 J/g. The composite material product prepared by using the above-mentioned hot-melt epoxy resin composition and its prepreg has no holes on the surface, smooth appearance and good molding quality. The prepreg storage period is 45 days.

Comparative Example 1

Step (1): 17.1 kg of the polyfunctional glycidyl ester alicyclic epoxy resin (TDE-85, Tianjin Jingdong Chemical Co., Ltd.) in the main epoxy resin was heated to 120° C. to melt, and 1 kg of polyvinyl butyral was added. Aldehyde, heat preservation for 30-90min to completely dissolved and transparent state to obtain component A;

Step (2): 3.1 kg of low-viscosity epoxy resin bisphenol F glycidyl ether (830s, Shanghai Synthetic Resin Factory) in the main epoxy resin, 1 kg of curing agent (modified dicyandiamide, commercially available), accelerator (1,1 dimethyl-3-phenylurea) 0.24kg was added to the premix and ground for 40min by a three-roller grinding device to obtain component B;

Step (3): The component A in (1) and the component B in (2) are blended at 70° C. for 30 minutes to obtain a medium-temperature curing and low exothermic hot-melt epoxy resin composition.

The hot-melt epoxy resin composition was used as the resin matrix to coat the hot-melt adhesive film, and then compounded with T300 carbon fiber to obtain a hot-melt prepreg, and the mass percentage of the resin matrix was controlled to be 36%.

A DSC (DSC2500, TA company) was used to scan at a heating rate of 10°C/min, and the reaction exotherm was 252 J/g. The composite material product prepared by using the above-mentioned hot-melt epoxy resin composition and its prepreg has holes on the surface, and the molding quality is good. The prepreg storage period is 20 days.

Comparative Example 2

Step (1): 17.1 kg of the polyfunctional glycidyl ester alicyclic epoxy resin (TDE-85, Tianjin Jingdong Chemical Co., Ltd.) in the main epoxy resin was heated to 120° C. to melt, and 1 kg of polyvinyl butyral was added. Aldehyde, heat preservation for 30-90min to completely dissolved and transparent state to obtain component A;

Step (2): 3.1 kg of low-viscosity epoxy resin bisphenol F glycidyl ether (830s, Shanghai Synthetic Resin Factory) in the main epoxy resin, 1 kg of curing agent (modified dicyandiamide, commercially available), accelerator (IA) 0.24kg was added to premix and ground for 40min by three-roll grinding equipment to obtain component B;

Step (3): The component A in (1) and the component B in (2) are blended at 70° C. for 30 minutes to obtain a medium-temperature curing and low exothermic hot-melt epoxy resin composition.

The hot-melt epoxy resin composition was used as the resin matrix to coat the hot-melt adhesive film, and then compounded with T300 carbon fiber to obtain a hot-melt prepreg, and the mass percentage of the resin matrix was controlled to be 36%.

A DSC (DSC2500, TA company) was used to scan at a heating rate of 10°C/min, and the reaction exotherm was 220 J/g. The composite material product prepared by using the above-mentioned hot-melt epoxy resin composition and its prepreg has no holes on the surface, and the molding quality is good. The prepreg storage period is 30 days.

Comparative Example 3

Step (1): 17.1 kg of the polyfunctional glycidyl ester alicyclic epoxy resin (TDE-85, Tianjin Jingdong Chemical Co., Ltd.) in the main epoxy resin was heated to 120° C. to melt, and 1 kg of polyvinyl butyral was added. Aldehyde, heat preservation for 30-90min to completely dissolved and transparent state to obtain component A;

Step (2): 3.1 kg of low-viscosity epoxy resin bisphenol F glycidyl ether (830s, Shanghai Synthetic Resin Factory) in the main epoxy resin, 1 kg of curing agent (modified dicyandiamide, commercially available), accelerator (IB) 0.24kg was added to premix, and ground for 40min by three-roll grinding equipment to obtain component B;

Step (3): The component A in (1) and the component B in (2) are blended at 70° C. for 30 minutes to obtain a medium-temperature curing and low exothermic hot-melt epoxy resin composition.

The hot-melt epoxy resin composition was used as the resin matrix to coat the hot-melt adhesive film, and then compounded with T300 carbon fiber to obtain a hot-melt prepreg, and the mass percentage of the resin matrix was controlled to be 36%.

A DSC (DSC2500, TA company) was used to scan at a heating rate of 10°C/min, and the reaction exotherm was 120 J/g. The composite material prepared by using the above hot-melt epoxy resin composition and its prepreg needs to be post-treated at 150° C. to be cured, and cannot be completely cured at 130° C. The prepreg storage period is 90 days.

An embodiment of the present invention has been described in detail above, but the content is only a preferred embodiment of the present invention, and cannot be considered to limit the implementation scope of the present invention. All equivalent changes and improvements made according to the application scope of the invention should still fall within the scope of the invention.

Claims (11)

1. an epoxy resin composition is characterized in that: comprise the component of following mass percentage: Main body epoxy resin 74%-92%, thermoplastic resin 4%-16%, curing agent 2.3%-8.6%, accelerator 0.8%-4.4%; The sum of the mass percentages of the above components is 100%. 2 . The epoxy resin composition according to claim 1 , wherein the main epoxy resin is a mixture of low viscosity epoxy resin and multifunctional epoxy resin. 3 . 3 . The epoxy resin composition according to claim 2 , wherein the low-viscosity epoxy resin is one of bisphenol A glycidyl ether and bisphenol F glycidyl ether or a combination thereof. 4 . 4. epoxy resin composition according to claim 2 is characterized in that: multifunctional epoxy resin is a kind of in glycidylamine, novolac epoxy resin, multifunctional glycidyl ester alicyclic epoxy resin or a combination thereof. 5 . The epoxy resin composition according to claim 1 , wherein the thermoplastic resin is one or a combination of polyvinyl formal, polyvinyl butyral, and polyether sulfone. 6 . 6. The epoxy resin composition according to claim 1, wherein the curing agent is one of dicyandiamide or modified dicyandiamide or a combination thereof. 7. epoxy resin composition according to claim 1, is characterized in that: accelerator is the composition of one or both in IA and IB; Wherein, the chemical structural formula of IA, IB is as follows:

8 . The epoxy resin composition according to claim 7 , wherein the accelerator is preferably a mass ratio of IA:IB composition of 1:0.2˜1:1.0. 9 . 9. the preparation method of a kind of epoxy resin composition described in claim 1-8, is characterized in that: comprise the steps: (1) Dissolving the multifunctional epoxy resin and thermoplastic resin in the main epoxy resin at 100-150° C., stirring for 30-120 minutes at a temperature until both are transparent, and obtaining component A; (2) adding the low-viscosity epoxy resin in the main epoxy resin, the curing agent and the accelerator in proportion to premix, and grinding by three-roll grinding equipment for 20-40min to obtain component B; (3) The component A in (1) and the component B in (2) are blended at 60-90° C. for 10-40 minutes to obtain a medium-temperature curing and low exothermic hot-melt epoxy resin composition. 10. A hot-melt prepreg, characterized in that the epoxy resin composition according to any one of claims 1-9 is used as a resin matrix. 11. A hot-melt prepreg, wherein the preparation method of the prepreg comprises: coating the epoxy resin composition according to any one of claims 1 to 9 as a resin matrix into a hot-melt adhesive film , and then compounding with reinforcing fibers or fabrics to prepare a hot-melt prepreg; wherein, the percentage and mass content of the resin matrix is 30% to 40%.