TW201917167A - Epoxy resin composition - Google Patents

Abstract

An epoxy resin composition is provided. The epoxy resin composition includes 80-100 parts by weight of a thermal curable epoxy resin, and 0.1-20 parts by weight of a branched rubber copolymer. The branched rubber copolymer includes a rubber polymer as a main portion, and a polymer composed of polyethylene glycol (PEG), derivatives of polyethylene glycol, polycaprolactone (PCL), derivatives of polycaprolacton, or a combination thereof as a branched chain.

Description

 Epoxy resin composition  

The present disclosure relates to an epoxy resin composition, and more particularly to an epoxy resin composition comprising a toughening agent.

Epoxy resin has good adhesiveness, corrosion resistance, water resistance, mechanical strength, dielectric properties, heat resistance, molding processability, low shrinkage and other characteristics, and low production cost, so the application field is wide. However, the most common drawback of such a general-purpose epoxy resin is that it is a high-density crosslinked polymer after the curing reaction, and the internal stress is high, resulting in high brittleness and poor impact resistance, thus creating a need for enhanced toughness.

It is known that liquid rubber can be used as a toughening agent for epoxy resins, and a terminal carboxyl group liquid nitrile rubber (CTBN) is most common. Through the introduction of liquid rubber, after the epoxy resin is hardened, a micro-phase separated rubber particle structure is formed, which has the effect of absorbing or weakening stress, and can improve the toughness, impact strength, ductility, thermal shock resistance and peeling resistance of the epoxy resin. Strength and low temperature shear properties make it widely used in adhesives (such as adhesives between plastics, metals and ceramic materials), shock-proof materials, oil-resistant hoses, composite materials (such as wind power blades, aircraft and yacht shells, glass) Fiber tubes), coatings (such as building materials, strengthening fluids, insulation, waterproofing, corrosion-resistant coatings), electronic sealing and potting, and even aerospace military applications.

However, the use of liquid rubber can form a microphase-separated structure in epoxy resin to improve the toughness of epoxy resin, but it usually faces the following problems: 1) the glass transition temperature is greatly reduced, and the heat resistance is lowered; 2) the elastic modulus and The tensile strength is significantly reduced; 3) the transparency cannot be maintained; 4) a high addition of 10-20% is generally required to achieve the desired toughening effect.

Previously, different liquid rubbers have been used as toughening agents for epoxy resins. For example, in the past, non-reactive liquid nitrile rubber was added to epoxy resin to increase the toughness of epoxy resin, but non-reactive liquid rubber is prone to incomplete microphase separation and incomplete crosslinking in epoxy resin. The problem is that the toughness is improved and the stability is not good. In addition, after the addition of the non-reactive liquid nitrile rubber, the heat resistance, rigidity and transparency of the epoxy resin are also remarkably lowered.

Carboxyl-terminated polybutadiene-acrylonitrile (CTBN) and carboxyl-terminated polybutadiene (CTPB) have also been used as toughening agents for epoxy resins, but they prevent heat resistance. The effect of reducing the properties is still insufficient, and the rigidity and transparency of the epoxy resin cannot be maintained.

Although hydroxyl-terminated liquid nitrile rubber (HTBN) can achieve the performance of similar carboxyl-containing liquid nitrile rubber (CTBN) at a lower cost, it still has a high addition amount, and the heat resistance, rigidity, and transparency of the epoxy resin cannot be avoided. Problems such as reduced sex.

Although epoxy terminated polybutadiene-acrylonitrile (ETBN) or epoxy terminated polybutadiene (ETPB) without prepolymerization can effectively improve epoxy resin Resilience, but also can not overcome the problems of heat resistance, rigidity, and transparency of epoxy resin, and the price is also high.

Diblock copolymer of polyethylene glycol-b-CTBN and triblock copolymer of polyethylene glycol-b-CTBN-b-polyethylene glycol can be effectively improved at low addition amount The toughness of epoxy resin. However, the diblock copolymer cannot maintain the heat resistance of the epoxy resin, and the glass transition temperature also greatly decreases as the amount of addition increases. Although the triblock copolymer can maintain the heat resistance of the epoxy resin, the raw material requires the use of a relatively high cost CTBN.

Therefore, as the performance requirements for products using epoxy resins increase, how to improve the toughness of epoxy resins without affecting other characteristics (such as heat resistance, rigidity, and transparency) has become an important development direction.

According to an embodiment, the present disclosure provides an epoxy resin composition comprising: 80 to 100 parts by weight of a heat curable epoxy resin; and 0.1 to 20 parts by weight of a branched rubber copolymer. The branched rubber copolymer comprises: a rubber polymer as a main body; and polyethylene glycol (PEG), a derivative of polyethylene glycol, polycaprolactone (PCL), and polycaprol A derivative of a lactone, or a combination of the foregoing, is used as a branch.

The above and other objects, features, and advantages of the present invention will become more apparent and understood.

Fig. 1 shows a transmission electron microscope (TEM) image of a section of the epoxy resin composition of Example 1.

The singular forms "a" and "the" It is to be understood that the phrase "comprises" or "an" is used in the specification to indicate the presence of the features, steps, operations, components, and/or components, but does not exclude additional one or more additional features, steps, and operations The presence of components, components, and/or combinations thereof.

The phrase "an embodiment" or "an embodiment" or "an embodiment" or "an embodiment" is intended to mean that the particular features, structures, or characteristics described in the embodiments are included in the embodiments. Thus, appearances of the phrases "in an embodiment" or "in an embodiment" are not necessarily the same embodiment. In addition, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

In order to solve the problems faced by conventional liquid rubber toughening epoxy resin, the present disclosure provides a branched rubber copolymer as a toughening agent for epoxy resin. The toughening agent can reduce the toughness of the epoxy resin, and can also reduce the heat resistance, rigidity, tensile strength, transparency and the like of the epoxy resin.

An embodiment of the present invention provides an epoxy resin composition comprising: 80 to 100 parts by weight of a heat-curable epoxy resin, and 0.1 to 20 parts by weight of a branched rubber copolymer. For example, in some embodiments, the epoxy resin composition may include: 85 to 95 parts by weight of a heat-curable epoxy resin, and 5 to 15 parts by weight of a branched rubber copolymer. If the content of the branched rubber copolymer is too small, the toughness of the epoxy resin cannot be effectively improved. If the content of the branched rubber copolymer is too large, the effect of toughening the epoxy resin is limited, and it is disadvantageous to other physical properties.

In some embodiments, the heat curable epoxy resin may include 100 parts by weight of an epoxy resin, 5 to 120 parts by weight of a hardener, and 0 to 2 parts by weight of a promoter. For example, in some embodiments, the heat curable epoxy resin may include 100 parts by weight of epoxy resin, 90 to 95 parts by weight of a hardener, and 0.1 to 0.5 parts by weight of a promoter.

In some embodiments, the epoxy resin may include: bisphenol A type epoxy resin, novolac epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, Halogenated bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, polyfunctional glycidyl ether resin, polyfunctional glycidylamine resin, heterocyclic epoxy resin, or a combination thereof. In some embodiments, the hardener may include: methyltetrahydrophthalic anhydride (MTHPA), methyl hexahydrophthalic anhydride, succinic anhydride, dicyandiamide, m-phenylenediamine, triethylene glycol Tetraamine, polyetheramine, diaminodiphenylhydrazine, polyethyleneimine, or a combination of the foregoing. In some embodiments, the promoter may include: 1-Methyl-imidazole, 2,4,6-tris(dimethylaminomethyl)phenol, 3-(3,4-dichlorobenzene Base-1,1-dimethylurea, benzyltriethylammonium chloride, or a combination of the foregoing. Those skilled in the art will be able to select suitable types and proportions of epoxy resins, hardeners, and accelerators to form heat curable epoxy resins, depending on the desired properties.

In some embodiments, the branched rubber copolymer may comprise a rubber polymer as a host, and a polyethylene glycol (PEG), a derivative of polyethylene glycol, a polycaprolactone (polycaprolactone). A polymer composed of PCL), a derivative of polycaprolactone, or a combination of the foregoing is used as a branch.

In some embodiments, the branched rubber copolymer has a temperature of 1 to 500 Pa below 100 ° C. s viscosity, for example: 1~200Pa. s or 10~120Pa. s viscosity. If the viscosity of the rubber polymer is too small, the effect of toughening the epoxy resin cannot be achieved. If the viscosity of the rubber polymer is too large, the workability of the formed epoxy resin composition may be poor.

In some embodiments, the rubber polymer as the main body may include: a diene rubber, a hydrogenated diene rubber, an acrylate rubber, an ethylene propylene rubber, a butyl rubber, a ruthenium rubber, a homopolymer or a copolymer of a fluororubber, Or a combination of the foregoing homopolymers and copolymers.

In some embodiments, the monomer of the diene rubber may have the following structural formula:

Wherein R ¹ is H or CH ₃ .

In some embodiments, the monomer of the acrylate rubber may have the following structural formula:

Wherein R ² is H or CH ₃ ; R ³ is a saturated or unsaturated carbon chain of C ₄ to C ₃₅ , for example, a saturated or unsaturated carbon chain of C ₆ to C ₁₈ .

In some embodiments, the branched rubber copolymer may include: 0 to 15 mole percent of functional groups that can participate in the curing reaction of the heat curable epoxy resin, including: a carboxylic acid group, a hydroxyl group, an epoxy group , an amine group, or a combination of the foregoing. For example, in some embodiments, the branched rubber copolymer may further comprise: 5 to 12 mole percent of the above functional groups. When the branched rubber copolymer includes the above-mentioned functional group which can participate in the curing reaction of the heat-curable epoxy resin, the structural stability of the rubber can be strengthened, and the toughening efficiency is further enhanced.

In some embodiments, the functional group that can participate in the curing reaction of the heat curable epoxy resin is located on the rubber polymer or the branched polymer as the main body.

In some embodiments, the branched rubber copolymer may have a number average molecular weight of from 1,000 to 60,000, for example, from 3,000 to 20,000. In some embodiments, the number of polymers that are branched may have a number average molecular weight of from 300 to 30,000, such as from 500 to 6,000.

In some embodiments, the weight percentage of the polymer as a branched chain may be from 15 wt% to 65 wt%, such as from 25 wt% to 60 wt% or from 30 wt% to 50 wt%, based on the total weight of the branched rubber copolymer. If the content of the polymer as a branched chain is too small, the rubber polymer as the main body cannot be effectively dispersed in the epoxy resin and aggregated into a micron-sized rubber structure, resulting in difficulty in maintaining other physical properties of the epoxy resin, like general liquid rubber. Toughener. If the content of the polymer as a branched chain is too large, the content of the rubber polymer as a main component is insufficient, and the toughening effect on the epoxy resin is lowered.

It is worth mentioning that the positions of the branches of the branched rubber copolymer are in a random arrangement. The branch may be attached to the host rubber polymer by a copolymerization reaction or a graft reaction, wherein the copolymerization reaction mode is permeable to a macromonomer (such as polyethylene glycol acrylate) containing the branched structure. Copolymerized with rubber monomer. In addition, the grafting reaction mode may be carried out by using a branched polymer (such as polyethylene glycol monomethyl ester) to attach a grafting reaction point on the host rubber polymer (such as a carboxylic acid structure obtained by copolymerizing a rubber monomer with acrylic acid); Or a monomer (such as ethylene oxide or caprolactone) of a branched polymer is polymerized and grown by using the grafting reaction point as a starting point. Therefore, the present disclosure discloses a polyethylene glycol, a derivative of polyethylene glycol, a derivative of polycaprolactone, a derivative of polycaprolactone, or a combination thereof, which reacts with a rubber polymer, according to a reaction mechanism The rule is that the positions of the branches connected to the main rubber polymer are irregularly arranged. It is not limited to the ends of the rubber polymer, but rather forms a branched rubber copolymer as described in the present disclosure. The branched rubber copolymer of the present invention can enhance the anchoring force of the interface by entanglement between the branch and the epoxy resin compared to the diblock or triblock copolymer bonded to the end portion. (anchoring), to improve the structural stability of the rubber, can further demonstrate better toughness.

In some embodiments, the polyethylene glycol can comprise: a linear polyethylene glycol, a branched polyethylene glycol, a functionalized polyethylene glycol, or a combination of the foregoing. For example, in some embodiments, the polyethylene glycol structure may be a polyethylene glycol methyl ether methacrylate, a polyethylene glycol acrylate, or Provided by the combination of the foregoing. In some embodiments, the polycaprolactone may comprise: a linear polycaprolactone, a branched polycaprolactone, a functionalized polycaprolactone, or a combination of the foregoing.

As described above, the structure of the branched rubber copolymer provided by the present disclosure includes a rubber polymer as a main body and a polymer as a branch. It is worth mentioning that the rubber polymer as the main component in the branched rubber copolymer is incompatible with the epoxy resin, or is called epoxy-phobic, and in the branching The polymer which is branched in the rubber copolymer is compatible with the epoxy resin, or is referred to as epoxy-philic. The branched polymer in the branched rubber copolymer is compatible with the epoxy resin and has better solubility. Unlike the micron-scale phase separation of liquid rubber formation in the past, the properties of the branched rubber copolymer provided by the present disclosure allow it to form a nano rubber structure in the epoxy resin. Since the nano rubber structure can exhibit more uniform and stable dispersion, the branched rubber copolymer provided by the present disclosure can not only improve the toughness of the epoxy resin, but also maintain the original heat resistance, rigidity and resistance of the epoxy resin. The tensile strength, transparency and other characteristics solve the problems faced by conventional liquid rubber toughening epoxy resin.

The epoxy resin compositions provided by the present disclosure and their characteristics are illustrated by the following comparative examples and examples:

Preparation of branched rubber copolymer (toughening agent)

[Preparation Example 1]

53.8 g of polyethylene glycol methyl ether methacrylate (PEG-MA, Mn=950) was added to the autoclave, stirred and dissolved with 49.5 g of butanol, and purged with nitrogen to remove air. 64.5 g of isoprene and 4.5 g of azobisisobutyronitrile as a starter were introduced. The temperature was raised to 80 ° C and reacted for 56 hours. Next, after purification and drying, the product A is obtained.

The number average molecular weight (Mn) of the product A was analyzed by gel permeation chromatography (GPC) using polystyrene as a standard to be 7619. The molecular structure of the product A was analyzed by ¹ H NMR (solvent: CDCl ₃ ) to obtain a molar ratio of polyisoprene to polyethylene glycol of 94.4:5.6, which corresponds to the weight percentage of polyethylene glycol to product A. It is 45.3 wt%. The viscosity of the product A (Brookfield viscosity@27 ° C) was 15 Pa by analysis with a cone and plate viscometer. s.

[Preparation Example 2]

44.9 g of polyethylene glycol monomethyl ether methacrylate (Mn=950) was added to the autoclave, stirred and dissolved with 64.5 g of butanol, and nitrogen was purged to introduce 64.5 g of isoprene and 3.9. g is used as a starter for azobisisobutyronitrile. The temperature was raised to 80 ° C and reacted for 45 hours. Next, after purification and drying, product B is obtained.

The number average molecular weight (Mn) of the product B was analyzed by gel permeation chromatography (GPC) using polystyrene as a standard. The molecular structure of the product B was analyzed by ¹ H NMR (solvent is CDCl ₃ ) to obtain a molar ratio of polyisoprene to polyethylene glycol of 95.6:4.4, which corresponds to the weight percentage of polyethylene glycol to product B. It is 39.1 wt%. Analysis by cone and plate viscometer, the viscosity of product B (Brookfield viscosity@27 ° C) was 23Pa. s.

[Preparation Example 3]

13 g of polyethylene glycol monomethyl ether methacrylate (Mn=950) was added to the autoclave, stirred and dissolved with 15.5 g of butanol, and nitrogen gas was purged to introduce 15 g of 1,3-butadiene. 1,3-butadiene) and 1.7 g of azobisisobutyronitrile as a starter. The temperature was raised to 70 ° C and reacted for 40 hours. Next, after purification and drying, the product product C is obtained.

Using a polystyrene as a standard, the number average molecular weight (Mn) of the product C was analyzed by gel permeation chromatography (GPC) to be 7051. The molecular structure of the product C was analyzed by ¹ H NMR (solvent is CDCl ₃ ) to obtain a molar ratio of polybutadiene to polyethylene glycol of 95.3:4.7, which is equivalent to the weight percentage of polyethylene glycol to product C. 46.5 wt%. The viscosity of the product C (Brookfield viscosity@27 ° C) was 18 Pa. s.

[Preparation Example 4]

16.6 g of polyethylene glycol monomethyl ether methacrylate (Mn=950) was added to the autoclave, stirred and dissolved with 24 g of butanol, and nitrogen gas was purged to introduce 24 g of 1,3-butadiene. 2.9 g of azobisisobutyronitrile as a starter. The temperature was raised to 80 ° C and reacted for 40 hours. Next, after purification and drying, the product D1 is obtained.

Using a polystyrene as a standard, the number average molecular weight (Mn) of the product D1 was analyzed by a gel permeation chromatography (GPC) to be 5,504. The molecular structure of the product D1 was analyzed by ¹ H MNR (solvent is CDCl ₃ ), and the molar ratio of polybutadiene to polyethylene glycol was 96.5:3.5, which is equivalent to the weight percentage of polyethylene glycol to product D1. 38.9 wt%.

Next, 15 g of product D1 and 1.44 g of triphenylphosphine were added to the autoclave, dissolved by stirring with 100 g of methyl ethyl ketone, and nitrogen was purged, and then 27 mg of (1,5-cyclooctadiene) chloranil (I) was added. Dimer (Chloro (1,5-cyclooctadiene) rhodium (I) dimer) (CAS: 12092-47-6). 1000 psi of hydrogen was introduced, and the temperature was raised to 100 ° C and reacted for 16 hours. Next, after purification and drying, the product D2 is obtained. The degree of hydrogenation of the product D2 was analyzed by ¹ H NMR (solvent: CDCl ₃ ) to afford the product D2 to have a degree of hydrogenation of 99.5%, and the polyethylene glycol as a percentage by weight of the product D2 was 37.3 wt%. Using a polystyrene as a standard, the number average molecular weight (Mn) of the product D2 was analyzed by gel permeation chromatography (GPC) to be 6033. Analysis by cone and plate viscometer, the viscosity of product D2 (Brookfield viscosity@50 °C) was 55Pa. s.

[Preparation Example 5]

9.2 g of polyethylene glycol monomethyl ether methacrylate (Mn=2000) and 0.75 g of methacrylic acid were added to the autoclave, stirred and dissolved with 21.5 g of butanol, and purged with nitrogen to remove air. 21.5 g of isoprene and 1 g of azobisisobutyronitrile were introduced as a starter. The temperature was raised to 80 ° C and reacted for 47 hours. Next, after purification and drying, the product E is obtained.

The number average molecular weight (Mn) of the product E was analyzed by gel permeation chromatography (GPC) using polystyrene as a standard. The molecular structure of the product E was analyzed by ¹ H NMR (solvent: CDCl ₃ ) to obtain a molar ratio of polyisoprene to polyethylene glycol of 98.6:1.4, which corresponds to the weight percentage of polyethylene glycol to product E. It is 29.4% by weight.

The acid value of product E was 22 mg KOH/g as measured by acid-base titration, corresponding to a product of product E containing 6.2 mole percent of carboxylic acid functional groups. The viscosity of the product E (Brookfield viscosity@75 ° C) was 68 Pa. s.

[Preparation Example 6]

1 g of 2-ethylhexyl acrylate, 7.5 g of stearyl methacrylate, 0.5 g of glycidyl methacrylate, and 3.9 g were added to the reaction vessel. Polyethylene glycol monomethyl ether methacrylate (Mn=2000), dissolved in 12 g of toluene, and purged with nitrogen. After adding 0.015 g of azobisisobutyronitrile as a starter and 0.7 g of ten Didecanethiol. The temperature was raised to 70 ° C and reacted for 24 hours. Next, after purification and drying, the product F is obtained.

The number average molecular weight (Mn) of the product F was analyzed by gel permeation chromatography (GPC) using polystyrene as a standard. The molecular structure of the product F was analyzed by ¹ H NMR (solvent: CDCl ₃ ) to obtain a molar ratio of poly(meth)acrylate to polyethylene glycol of 93.8:6.2, which corresponds to polyethylene glycol as the product F. The weight percentage was 31.3 wt%. In addition, product F contained 10.5 mole percent of epoxy functional groups. The viscosity of the product F (Brookfield viscosity@75 ° C) was 112 Pa. s.

[Preparation Example 7]

15 g of caprolactone (ε-caprolactone) was placed in a reaction flask, and air was purged with nitrogen to raise the temperature to 130 ° C. 1.9 g of 2-hydroxyethyl methacrylate and 0.018 g of stannous isooctylate were added. Stannous octoate) and stirred evenly. After 16 hours of reaction, the temperature was lowered to obtain HEMA-PCL. The molecular weight of HEMA-PCL was calculated to be 1194 by ¹ H NMR (solvent as CDCl ₃ ).

9 g of stearyl methacrylate and 11 g of HEMA-PCL were added to the reaction vessel, dissolved in 9 g of butanol, and nitrogen was purged. After adding air, 0.06 g of azo diiso was used as a starter. Nitrile and 0.23 g of dodecanethiol. The temperature was raised to 70 ° C and reacted for 24 hours. Next, after purification and drying, the product G is obtained.

The number average molecular weight (Mn) of the product G was analyzed by gel permeation chromatography (GPC) using polystyrene as a standard to be 19864. The molecular structure of the product G was analyzed by ¹ H NMR (solvent is CDCl ₃ ) to obtain a molar ratio of polymethacrylate to polycaprolactone of 74.1:25.9, which is equivalent to the weight percentage of polycaprolactone to product G. It is 55.2% by weight. The viscosity of the product G (Brookfield viscosity@75 ° C) was 81 Pa by analysis with a cone and plate viscometer. s.

Table 1

[Comparative Example 1]

100 parts by weight of bisphenol A type epoxy resin (Araldite LY556 from Huntsman), 90 parts by weight of methyltetrahydrophthalic anhydride (MTHPA) as a hardener, and 0.5 parts by weight As a promoter, 1-methyl-imidazole was stirred and mixed at 50 ° C with a stirrer and vacuum defoamed to obtain an epoxy resin matrix. Next, the epoxy resin substrate was poured into a test piece mold, and the mixture was thermostated at 80 ° C for 4 hours, followed by a hardening procedure at 140 ° C for 8 hours to obtain a test piece of the epoxy resin composition. The test piece size was determined according to the ASTM test method.

[Comparative Example 2-1]

95 parts by weight of the epoxy resin substrate of Comparative Example 1 was stirred at 50 ° C, and 5 parts by weight of CTBN (Hypro 1300x13 available from CVC) was added as a toughening agent, and after stirring for 1 hour, vacuum defoaming was carried out. The mixture was poured into a test piece mold, and the mixture was heated at 80 ° C for 4 hours, followed by a hardening procedure at 140 ° C for 8 hours to obtain a test piece of the epoxy resin composition. The test piece size was determined according to the ASTM test method.

[Comparative Example 2-2]

Similar to Comparative Example 2-1, the difference was that the amount of the epoxy resin matrix was reduced to 90 parts by weight, and the amount of the toughening agent CTBN was increased to 10 parts by weight.

[Comparative Example 2-3]

Similar to Comparative Example 2-1, the difference was that the amount of the epoxy resin matrix was reduced to 85 parts by weight, and the amount of the toughening agent CTBN was increased to 15 parts by weight.

Epoxy resin composition

[Example 1]

95 parts by weight of the epoxy resin substrate of Comparative Example 1 was stirred at 50 ° C, and 5 parts by weight of PI-g-PEG of Preparation Example 1 was added as a toughening agent, and after stirring for 20 minutes, vacuum defoaming was carried out. The mixture was poured into a test piece mold, and the mixture was heated at 80 ° C for 4 hours, followed by a hardening procedure at 140 ° C for 8 hours to obtain a test piece of the epoxy resin composition. The test piece size was determined according to the ASTM test method.

[Embodiment 2]

Similar to Example 1, the difference was that the product B of Preparation Example 2 was used as a toughening agent.

[Example 3]

Similar to Example 1, the difference was that the product C of Preparation Example 3 was used as a toughening agent.

[Example 4]

Similar to Example 1, the difference was that the product D2 of Preparation Example 4 was used as a toughening agent.

[Example 5]

Similar to Example 1, the difference was that the product E of Preparation Example 5 was used as a toughening agent.

[Embodiment 6]

Similar to Example 1, the difference was that the product F of Preparation Example 6 was used as a toughening agent.

[Embodiment 7]

Similar to Example 1, the difference was that the product G of Preparation Example 7 was used as a toughening agent.

[Embodiment 8]

Similar to Example 2, the difference was that the epoxy resin matrix was 90 parts by weight, and the toughener product B was 10 parts by weight.

Performance evaluation of epoxy resin compositions

The resin properties were evaluated for Comparative Example 1, Comparative Example 2-1, Comparative Example 2-2, Comparative Example 2-3, and Example 1 to Example 8, respectively, including: (1) heat resistance (glass transition temperature; Tg, Test according to ASTM D3418); (2) Elastic modulus E (tested according to ASTM D638); (3) Tensile strength (tested according to ASTM D638); (4) Transparency (tested at 5 mm thickness) (5) Fracture toughness K1c (single-edge notched bending, SENB according to ASTM D5045; and (6) Fracture energy G1c (tested according to ASTM D5045). The test results are shown in Table 2 below.

Further, by analyzing a section of the epoxy resin composition of Example 1 dyed with ruthenium tetroxide (RuO ₄ ) by a transmission electron microscope (TEM), it was observed that a rubber structure having a size of about 10 to 50 nm was uniformly dispersed in the ring. In the oxyresin, micron phase microphase separation was not observed, as shown in Fig. 1.

[Note 1] ○: The test piece can be seen to the background; X: The test piece cannot be seen to the background.

It can be seen from Table 2 that by adding 5 parts by weight of the toughening agents of Preparation Examples 1 to 8 to the epoxy resin matrix (ie, Examples 1 to 8), the fracture toughness (K1c) and the fracture energy of the epoxy resin can be effectively improved ( G1c). In detail, the fracture toughness of Examples 1 to 8 was more than twice as high as that of the pure epoxy resin (Comparative Example 1) to which no toughening agent was added, and the fracture energy was higher than that of the pure epoxy resin to which the toughening agent was not added (Comparative Example) 1) Increase by more than four times. Further, the fracture toughness of Examples 1 to 8 was higher than that of the epoxy resin (Comparative Example 2-3) to which 15 parts by weight of CTBN was added, and the fracture energy was higher than that of the epoxy resin to which 10 parts by weight of CTBN was added (Comparative The breaking energy of Example 2-2). In particular, the toughening agent of Example 5 contains a carboxylic acid functional group reactive with an epoxy resin, which exhibits enhanced toughness. These results show that the epoxy resin compositions of Examples 1 to 8 all exhibited excellent toughening effects.

Further, as is clear from Table 2, the heat resistance (glass transition temperature; Tg), elastic modulus (rigidity), and transparency of Examples 1 to 8 can be maintained with pure epoxy resin without adding a toughening agent (Comparative Example 1) It is similar, and the tensile strength is higher than that of CTBN as a toughening agent (Comparative Examples 2-1 to 2-3).

It can be seen from the results of the above Comparative Examples and Examples that the branched rubber copolymer provided by the present disclosure can exhibit excellent performance as a toughening agent for epoxy resin, and solve the conventional liquid rubber type toughening agent (such as CTBN). The problem of high addition amount, heat resistance, rigidity, tensile strength and transparency when toughening epoxy resin.

The present disclosure has been disclosed in the above-described preferred embodiments, and is not intended to limit the disclosure. Any one of ordinary skill in the art can make any changes without departing from the spirit and scope of the disclosure. And the scope of protection of this disclosure is subject to the definition of the scope of the patent application.

Claims (17)

 An epoxy resin composition comprising: 80 to 100 parts by weight of a heat-curable epoxy resin; and 0.1 to 20 parts by weight of a branched rubber copolymer, the branched rubber copolymer comprising: a rubber polymer As a main body; and a polymer as a branch, which is made of polyethylene glycol (PEG), a derivative of polyethylene glycol, polycaprolactone (PCL), polycaprolactone A derivative, or a combination of the foregoing.    The epoxy resin composition according to claim 1, wherein the heat curable epoxy resin comprises: 100 parts by weight of an epoxy resin; 5 to 120 parts by weight of a hardener; and 0 to 2 parts by weight. Promoter.    The epoxy resin composition according to claim 2, wherein the epoxy resin comprises: bisphenol A type epoxy resin, novolac epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy Resin, cycloaliphatic epoxy resin, halogenated bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, polyfunctional glycidyl ether resin, polyfunctional glycidylamine resin, heterocyclic epoxy resin, or Combination of the foregoing.    The epoxy resin composition according to claim 2, wherein the hardener comprises: methyltetrahydrophthalic anhydride (MTHPA), methyl hexahydrophthalic anhydride, succinic anhydride, dicyandiamide Amine, m-phenylenediamine, triethylenetetramine, polyetheramine, diaminodiphenylhydrazine, polyethyleneimine, or a combination of the foregoing.    The epoxy resin composition according to claim 2, wherein the accelerator comprises: methylimidazole (1-Methyl-imidazole), 2,4,6-tris(dimethylaminomethyl)phenol, 3 -(3,4-Dichlorophenyl)-1,1-dimethylurea, benzyltriethylammonium chloride, or a combination of the foregoing.    The epoxy resin composition according to claim 1, wherein the rubber copolymer has a temperature of 1 to 500 Pa below 100 ° C. s viscosity.    The epoxy resin composition according to claim 1, wherein the rubber polymer comprises: a diene rubber, a hydrogenated diene rubber, an acrylate rubber, an ethylene propylene rubber, a butyl rubber, a ruthenium rubber, a fluororubber A homopolymer or copolymer, or a combination of the foregoing homopolymers and copolymers.   The epoxy resin composition according to claim 7, wherein the monomer of the diene rubber has the following structural formula: Wherein R ¹ is H or CH ₃ . The epoxy resin composition according to claim 7, wherein the monomer of the acrylate rubber has the following structural formula: Wherein R ² is H or CH ₃ ; and R ³ is a saturated or unsaturated carbon chain of C ₄ to C ₃₅ .  The epoxy resin composition according to claim 1, wherein the branched rubber copolymer comprises: 0 to 15 mole percent of functional groups which can participate in a curing reaction of the heat curable epoxy resin, including: A carboxylic acid group, a hydroxyl group, an epoxy group, an amine group, or a combination of the foregoing.    The epoxy resin composition according to claim 10, wherein the functional group which can participate in the curing reaction of the heat-curable epoxy resin is located in the rubber polymer as a main body or the polymer as a branch on.    The epoxy resin composition according to claim 1, wherein the branched rubber copolymer has a number average molecular weight of from 1,000 to 60,000.    The epoxy resin composition according to claim 1, wherein the polymer having a branched chain has a number average molecular weight of from 300 to 30,000.    The epoxy resin composition according to claim 1, wherein the polymer is branched as a weight percentage of 15% by weight to 65% by weight based on the total weight of the branched rubber copolymer.    The epoxy resin composition of claim 1, wherein the branch of the branched rubber copolymer is in a random arrangement.    The epoxy resin composition of claim 1, wherein the polyethylene glycol comprises: a linear polyethylene glycol, a branched polyethylene glycol, a functionalized polyethylene glycol, or a combination thereof.    The epoxy resin composition of claim 1, wherein the polycaprolactone comprises: a linear polycaprolactone, a branched polycaprolactone, a functionalized polycaprolactone, or a combination thereof.