JP6403988B2 - Curable resin composition and resin cured product - Google Patents

Description

The present invention relates to a curable resin composition capable of exhibiting excellent impact resistance and heat resistance after curing. The present invention also relates to a cured resin product produced by curing the curable resin composition.

The epoxy resin adhesive is an adhesive that is cured by a reaction between the epoxy resin and the curing agent by heating, and takes, for example, a one-component or two-component liquid or film form. Epoxy resin adhesives are widely used in various fields because their cured products have excellent adhesion, heat resistance, chemical resistance, electrical properties, and the like. In particular, when a bisphenol type epoxy resin is used, a cured product having high heat resistance can be obtained.
However, the epoxy resin adhesive has a problem that its cured product is generally brittle and insufficient in flexibility and inferior in impact resistance.

In order to improve impact resistance, it has been studied to use an epoxy resin in combination with a compound having a highly flexible polysiloxane skeleton. In particular, since an epoxy resin and a compound having a polysiloxane skeleton are poorly compatible, various attempts have been made to improve the compatibility. For example, Patent Document 1 uses a block copolymer composed of an aromatic resin and a polysiloxane compound as a compatibilizer for the polysiloxane compound, in which a polysiloxane compound is dispersed in a curable resin. A cured curable resin composition is described.
However, when an epoxy resin and a compound having a polysiloxane skeleton are compatible, a high glass transition temperature (Tg) of the epoxy resin is lowered, resulting in a problem that heat resistance is lowered. Also, impact resistance did not improve as expected.

In order to prevent such a decrease in heat resistance, it has been studied to make the cured product a phase separation structure. For example, Patent Documents 2 and 3 describe a heat-resistant adhesive and a heat-resistant resin composition containing an epoxy resin and a siloxane-modified polyamideimide capable of forming a phase separation structure.
However, it is difficult to form a good phase separation structure and maintain the phase separation structure even when heat is applied, and curable resin compositions capable of satisfying both sufficiently high impact resistance and heat resistance have hitherto been used. It was not obtained.

JP-A-5-302033 JP 2001-152125 A JP 2001-139809 A

An object of this invention is to provide the curable resin composition which can exhibit the impact resistance and heat resistance which were excellent after hardening. Another object of the present invention is to provide a cured resin product produced by curing the curable resin composition.

The present invention provides (a) 50 to 90 parts by weight of at least one epoxy resin selected from the group consisting of (a) bisphenol type epoxy resin, dicyclopentadiene type epoxy resin, anthracene type epoxy resin and biphenyl type epoxy resin, (b) A curable resin composition containing 10 to 50 parts by weight of a polysiloxane compound having a plurality of (meth) acrylic groups and one or more ether groups, (c) an epoxy resin curing agent, and (d) a radical polymerization initiator It is a thing.
The present invention is described in detail below.

The inventor of the present invention provides a curable resin composition containing a predetermined epoxy resin and a polysiloxane compound having a plurality of (meth) acrylic groups and one or more ether groups in a predetermined compounding amount after curing. A phase separation structure is formed, and it is found that a high glass transition temperature (Tg) and low thermal stress can be obtained while maintaining impact resistance (that is, excellent heat resistance can be exhibited), and the present invention is completed. I came to let you.

The curable resin composition of the present invention comprises (a) at least one epoxy resin selected from the group consisting of a bisphenol type epoxy resin, a dicyclopentadiene type epoxy resin, an anthracene type epoxy resin, and a biphenyl type epoxy resin. Parts by weight, (b) 10-50 parts by weight of a polysiloxane compound having a plurality of (meth) acrylic groups and one or more ether groups, (c) an epoxy resin curing agent, and (d) a radical polymerization initiator. contains.

By containing the (a) epoxy resin, the curable resin composition of the present invention has improved heat resistance after curing. Of these, anthracene type epoxy resins are preferable.

The bisphenol type epoxy resin is not particularly limited as long as it has a bisphenol skeleton and an epoxy group, and examples thereof include epoxy resins such as bisphenol A type, bisphenol F type, bisphenol AD type, and bisphenol S type. These bisphenol-type epoxy resins may be used independently and may use 2 or more types together. Of these, bisphenol A type epoxy resins and bisphenol F type epoxy resins are preferred because of their high versatility.

If the epoxy equivalent of the bisphenol-type epoxy resin exceeds 1000, it may not be compatible with the polysiloxane compound (b) above, so 1000 or less is preferable. A more preferable upper limit of the epoxy equivalent is 500.

Commercially available products of the above bisphenol type epoxy resins include, for example, EP-4100E (bisphenol A type epoxy, epoxy equivalent 190, manufactured by ADEKA), YDF-170 (bisphenol F type epoxy, epoxy equivalent 170, manufactured by Nippon Steel Chemical Co., Ltd.) Etc.

The dicyclopentadiene type epoxy resin is not particularly limited as long as it has a dicyclopentadiene skeleton and an epoxy group, and examples thereof include an epoxy resin represented by the following general formula (1). These dicyclopentadiene type epoxy resins may be used alone or in combination of two or more.

In general formula (1), m R each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a t-butyl group. n represents an integer of 0 to 4, and m represents an integer of 1 to 3.

If the epoxy equivalent of the dicyclopentadiene type epoxy resin exceeds 1000, it may not be compatible with the polysiloxane compound (b) above, so 1000 or less is preferable. A more preferable upper limit of the epoxy equivalent is 500.

As a commercial item of the said dicyclopentadiene type epoxy resin, for example, HP-7200L (epoxy equivalent 247, manufactured by DIC), HP-7200H (epoxy equivalent 278, manufactured by DIC), HP-7200 (epoxy equivalent 257, DIC) Manufactured) and the like.

The anthracene type epoxy resin is not particularly limited as long as it has an anthracene skeleton and an epoxy group, and examples thereof include an epoxy resin represented by the following general formula (2).

In general formula (2), R < ¹ > -R < ⁴ > represents a hydrogen atom or a C1-C5 alkyl group each independently.

When the epoxy equivalent of the anthracene-type epoxy resin exceeds 1000, it may not be compatible with the polysiloxane compound (b) above, so 1000 or less is preferable. A more preferable upper limit of the epoxy equivalent is 500.

As a commercial item of the said anthracene type epoxy resin, YX8800 (Anthracene type epoxy, epoxy equivalent 179, Mitsubishi Chemical Corporation make) etc. are mentioned, for example.

The biphenyl type epoxy resin is not particularly limited as long as it has a biphenyl skeleton and an epoxy group, and examples thereof include an epoxy resin represented by the following general formula (3). These biphenyl type epoxy resins may be used independently and may use 2 or more types together.

In General Formula (3), R ^{1 to} R ⁸ represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and all may be the same or different. n represents an integer of 0 to 3.

If the biphenyl type epoxy resin has an epoxy equivalent of more than 1000, it may not be compatible with the polysiloxane compound (b) above, and is preferably 1000 or less. A more preferable upper limit of the epoxy equivalent is 500.

Examples of the commercially available biphenyl type epoxy resin include YX4000H (biphenyl type epoxy, epoxy equivalent 192, manufactured by Mitsubishi Chemical Corporation), YL6121H (biphenyl type epoxy, epoxy equivalent 175, manufactured by Mitsubishi Chemical Corporation), and the like.

Since the (b) polysiloxane compound has a highly flexible polysiloxane skeleton, the curable resin composition of the present invention has improved impact resistance after curing.
Here, usually, the epoxy resin and the compound having a polysiloxane skeleton are poorly compatible, but since the (b) polysiloxane compound has one or more ether groups, in the curable resin composition of the present invention, The compatibility between the (a) epoxy resin and the (b) polysiloxane compound is improved, and after curing, a phase-separated structure is formed and the impact resistance is maintained, while maintaining a high glass transition temperature (Tg) and Low thermal stress can be obtained (that is, excellent heat resistance can be exhibited). In addition, when other epoxy resins are used instead of the above (a) epoxy resin, the compatibility with the (b) polysiloxane compound is deteriorated, or the phase separation structure is changed after the curable resin composition is cured. It will stop forming.
In addition, since the (b) polysiloxane compound has a plurality of (meth) acryl groups in addition to one or more ether groups, in the curable resin composition of the present invention, the (a) epoxy after the curing. The resin and the (b) polysiloxane compound form a three-dimensional crosslinked structure. Thereby, the fluidity when heat is applied is suppressed and the phase separation structure is maintained, so that the heat resistance after curing is further improved.

The (b) polysiloxane compound is not particularly limited as long as it has a plurality of (meth) acryl groups, one or more ether groups, and a polysiloxane skeleton. For example, a plurality of (meth) acryl groups And one or more ether groups, polydimethylsiloxane, polymethylphenylsiloxane, and modified products thereof. The modified product means a compound having an organic group introduced in the side chain or terminal.

As for the weight average molecular weight of the said (b) polysiloxane compound, a preferable minimum is 300 and a preferable upper limit is 10,000. When the weight average molecular weight is less than 300, the flexibility of the polysiloxane compound (b) may be lowered, and the impact resistance after curing of the curable resin composition may be lowered. When the weight average molecular weight exceeds 10,000, the compatibility between the (a) epoxy resin and the (b) polysiloxane compound may deteriorate. The more preferable lower limit of the weight average molecular weight is 400, and the more preferable upper limit is 5000.

The preferable lower limit of the functional group equivalent ((meth) acrylic group equivalent) of the (b) polysiloxane compound is 150, and the preferable upper limit is 5000. When the functional group equivalent is less than 150, the impact resistance after curing of the curable resin composition may be lowered. If the functional group equivalent exceeds 5000, the curable resin composition may not sufficiently form a three-dimensional crosslinked structure after curing, and the heat resistance may decrease. The more preferable lower limit of the functional group equivalent is 200, and the more preferable upper limit is 2500.

The preferable lower limit of the ether group content of the (b) polysiloxane compound is 5% by weight, and the preferable upper limit is 90% by weight. When the ether group content is less than 5% by weight, the compatibility between the (a) epoxy resin and the (b) polysiloxane compound is deteriorated, or the impact resistance or heat resistance after curing of the curable resin composition is reduced. May deteriorate. When the ether group content exceeds 90% by weight, the compatibility between the (a) epoxy resin and the (b) polysiloxane compound becomes too good, and the curable resin composition can form a phase separation structure after curing. However, heat resistance may decrease. The more preferable lower limit of the ether group content is 10% by weight, and the more preferable upper limit is 80% by weight.
In addition, the ether group content of the (b) polysiloxane compound means the ratio of the formula weight of the ether group to the molecular weight of the (b) polysiloxane compound.

Content of the said (b) polysiloxane compound is 10-50 weight part with respect to 50-90 weight part of said (a) epoxy resins. When content of the said (b) polysiloxane compound is less than the said range, the impact resistance or heat resistance after hardening of curable resin composition will fall. When content of the said (b) polysiloxane compound exceeds the said range, the heat resistance after hardening of curable resin composition will fall. The more preferable lower limit of the content of the (b) polysiloxane compound is 30 parts by weight, and the more preferable upper limit is 50 parts by weight. On the other hand, the upper limit with more preferable content of the said (a) epoxy resin is 70 weight part.

The (c) epoxy resin curing agent is not particularly limited, and a conventionally known epoxy resin curing agent can be appropriately selected. For example, an acid anhydride curing agent, an imidazole curing agent, a phenol curing agent, and an amine curing agent. Examples of the curing agent include a latent curing agent such as dicyandiamide, and a cationic catalyst-type curing agent. These (c) epoxy resin curing agents may be used alone or in combination of two or more. Especially, since it is excellent in the physical property etc. of a resin hardened | cured material, an acid anhydride type hardening | curing agent and an imidazole type hardening | curing agent are preferable.

As a commercial item of the said acid anhydride type hardening | curing agent, YH-306, YH-307 (above, the Mitsubishi Chemical company make), YH-309 (Mitsubishi Chemical company make, acid anhydride type hardening agent) etc. are mentioned, for example. .
Examples of commercially available imidazole-based curing agents include 1-cyanoethyl-2-phenylimidazole in which the 1-position of imidazole is protected with a cyanoethyl group, and an imidazole-based curing accelerator whose basicity is protected with isocyanuric acid (trade name “2MA- OK ”, manufactured by Shikoku Kasei Kogyo Co., Ltd.), 2MZ, 2MZ-P, 2PZ, 2PZ-PW, 2P4MZ, C11Z-CNS, 2PZ-CNS, 2PZCNS-PW, 2MZ-A, 2MZA-PW, C11Z-A, 2E4MZ- A, 2MAOK-PW, 2PZ-OK, 2MZ-OK, 2PHZ, 2PHZ-PW, 2P4MHZ, 2P4MHZ-PW, 2E4MZ · BIS, VT, VT-OK, MAVT, MAVT-OK (above, manufactured by Shikoku Kasei Kogyo Co., Ltd.) Etc.

Although content of the said (c) epoxy resin hardening | curing agent is not specifically limited, A preferable minimum is 0.1 weight part and a preferable upper limit is 500 weight part with respect to 100 weight part of said (a) epoxy resins. If the content is less than 0.1 parts by weight, the curable resin composition may not be sufficiently cured, or it may require heating at a high temperature for a long time for curing. Even if the content exceeds 500 parts by weight, it does not particularly contribute to the curability of the curable resin composition.

The (d) radical polymerization initiator is not particularly limited, and examples thereof include azobisisobutyronitrile such as AIBN (2,2′-azobis (isobutyronitrile), azobiscyclohexanecarbonitrile, 2,2′- Azobis (2,4-dimethylvaleronitrile), t-butylperoxy-2-ethylhexanoate (for example, perbutyl O manufactured by NOF Corporation), t-butyl peroxybenzoate (for example, perbutyl manufactured by NOF Corporation) Z) and the like.

Although content of said (d) radical polymerization initiator is not specifically limited, A preferable minimum is 0.01 weight part and a preferable upper limit is 10 weight part with respect to 100 weight part of said (b) polysiloxane compounds. If the content is less than 0.01 parts by weight, the curable resin composition may not sufficiently form a three-dimensional crosslinked structure after curing, and the heat resistance may decrease. Even if the content exceeds 10 parts by weight, it does not particularly contribute to the curability of the curable resin composition.

It is preferable to use a curing agent having a relatively slow curing reaction as the (c) epoxy resin curing agent and an initiator having a relatively fast curing reaction as the (d) radical polymerization initiator. Thereby, the difference in the reaction rate between the curing reaction of the (a) epoxy resin and the curing reaction of the (b) polysiloxane compound is increased, and as a result, a phase separation structure is easily formed after curing.
As a combination of the above (c) epoxy resin curing agent and the above (d) radical polymerization initiator, for example, 2-ethyl-4-methylimidazole (for example, 2E4MZ manufactured by Shikoku Kasei Kogyo Co., Ltd.) and 2, Combination with 2′-azobis (isobutyronitrile) (for example, AIBN manufactured by Wako Pure Chemical Industries, Ltd.), 1-cyanoethyl-2-ethyl-4-methylimidazole (for example, 2E4MZ-CN manufactured by Shikoku Kasei Kogyo Co., Ltd.) ) And 2,2′-azobis (2,4-dimethylvaleronitrile) (for example, ADVN manufactured by Wako Pure Chemical Industries, Ltd.), 2,4-diamino-6- [2′-methylimidazolyl- (1 ')]-Ethyl-s-triazine isocyanuric acid adduct (for example, 2MA-OK manufactured by Shikoku Kasei Kogyo Co., Ltd.) and t-butylperoxy-2-ethylhexanoate ( For example, a combination with NOF Corporation perbutyl O) is mentioned.

The method for producing the curable resin composition of the present invention is not particularly limited. For example, (a) the epoxy resin, (b) the polysiloxane compound, (c) the epoxy resin curing agent, and (d) above. The method of stirring and mixing a radical polymerization initiator using a homodisper etc. is mentioned.

Since the curable resin composition of the present invention forms a phase separation structure after curing, it has impact resistance. In addition, since the curable resin composition of the present invention can obtain a high glass transition temperature (Tg) after curing, that is, excellent heat resistance and low thermal stress, for example, in the electronic equipment field, the automobile field, etc. It is suitably used for applications.
The conditions for curing the curable resin composition of the present invention are not particularly limited. For example, the curable resin composition of the present invention can be cured under conditions of 150 ° C. for 2 hours. Such a cured resin produced by curing the curable resin composition of the present invention is also one aspect of the present invention.

The fact that the cured resin of the present invention has a phase separation structure means that a non-uniform phase structure is observed when observed with an electron microscope (for example, a transmission electron microscope JEM-2100 (manufactured by JEOL Ltd.)). Can be confirmed. As an example, FIG. 1 shows a transmission electron micrograph of a cured resin product produced by curing the curable resin composition obtained in Example 1 at 150 ° C. for 2 hours. In the transmission electron micrograph shown in FIG. 1, the black portion is a phase composed of (b) a polysiloxane compound, and the white portion is a phase composed of (a) an epoxy resin.
However, the phase separation structure of the resin cured product of the present invention is not limited to the phase separation structure as shown in FIG.

Moreover, it can also be confirmed that the resin cured product of the present invention has a phase separation structure by observing two tan δ peaks when the glass transition temperature (Tg) is measured.
The glass transition temperature (Tg) of the cured resin product of the present invention is preferably 120 ° C. or higher, more preferably 150 ° C. or higher. The glass transition temperature (Tg) of the cured resin is, for example, a sample length of 30 mm by a dynamic viscoelasticity measuring device (for example, a dynamic viscoelasticity measuring device DVA-200 (made by IT Measurement Control Co., Ltd.)). Further, the measurement can be performed under the conditions of a chuck interval of 20 mm, a frequency of 10 Hz, and a heating rate of 10 ° C./min.

The upper limit with the preferable thermal stress of the resin cured material of this invention is 20 Mpa. When the thermal stress exceeds 20 Mpa, particularly when used in the field of electronic equipment, the durability against thermal history may be insufficient. The thermal stress of the cured resin can be obtained from the storage elastic modulus and the linear expansion coefficient.

The minimum with preferable impact resistance of the resin cured material of this invention is 5 kJ / m < ² >. The impact resistance of the cured resin is the impact when a Charpy impact test is performed using a digital impact tester DG-UB (Toyo Seiki Seisakusho) according to JIS K7111, and the cured resin is destroyed. It is a value obtained by evaluating the value.

ADVANTAGE OF THE INVENTION According to this invention, the curable resin composition which can exhibit the outstanding impact resistance and heat resistance after hardening can be provided. Moreover, according to this invention, the resin cured material manufactured by hardening | curing this curable resin composition can be provided.

2 is a transmission electron micrograph of a cured resin product produced by curing the curable resin composition obtained in Reference Example 1 under conditions of 150 ° C. for 2 hours.

Examples of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

( Examples 7 to 17 , Comparative Examples 1 to 12, Reference Examples 1 to 6 )
According to the composition described in Tables 1 to 3, the materials shown below were stirred and mixed using a homodisper to prepare a curable resin composition.

(A) Epoxy resin / EP-4100E (bisphenol A type epoxy, epoxy equivalent 190, manufactured by ADEKA)
・ YDF-170 (bisphenol F type epoxy, epoxy equivalent 170, manufactured by Nippon Steel Chemical Co., Ltd.)
-HP-7200L (dicyclopentadiene type epoxy resin, epoxy equivalent 247, manufactured by DIC)
-HP-7200H (dicyclopentadiene type epoxy resin, epoxy equivalent 278, manufactured by DIC Corporation)
YX8800 (anthracene type epoxy, epoxy equivalent 179, manufactured by Mitsubishi Chemical Corporation)
・ YX4000H (biphenyl type epoxy, epoxy equivalent 192, manufactured by Mitsubishi Chemical Corporation)
YL6121H (biphenyl type epoxy, epoxy equivalent 175, manufactured by Mitsubishi Chemical Corporation)

(A ′) Other epoxy resin / hydrogenated bisphenol A type epoxy (epoxy equivalent 205, manufactured by Mitsubishi Chemical Corporation)
YDCN-704 (o-cresol novolac type epoxy, epoxy equivalent 210, softening point 90 ° C., manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)

(B) Polysiloxane compound X-22-1602 (polydimethylsiloxane having an acrylic group and a polyether skeleton, functional group equivalent 1200, manufactured by Shin-Etsu Chemical Co., Ltd.)
BYK-UV3530 (polydimethylsiloxane having an acrylic group and a polyether skeleton, manufactured by Big Chemie Japan)
-TEGO Rad 2200N (polydimethylsiloxane having an acrylic group and a polyether skeleton, manufactured by Evonik Degussa Japan)

(B ′) Other polysiloxane compound • X-22-164A (polydimethylsiloxane having a methacryl group, functional group equivalent 860, manufactured by Shin-Etsu Chemical Co., Ltd.)
・ KF-353 (polydimethylsiloxane having a polyether skeleton, functional group equivalent 0, manufactured by Shin-Etsu Chemical Co., Ltd.)

(C) Epoxy resin curing agent 2E4MZ (2-ethyl-4-methylimidazole, manufactured by Shikoku Chemicals)

(D) Radical polymerization initiator / AIBN (2,2′-azobis (isobutyronitrile), manufactured by Wako Pure Chemical Industries, Ltd.)

<Evaluation>
The following evaluation was performed about the curable resin composition obtained by the Example, the comparative example, and the reference example . The results are shown in Tables 1-3.

(1) The compatibility between the epoxy resin and the polysiloxane compound was evaluated by visually observing the compatible curable resin composition. The case where there was no separation was marked with ◯, and the case where it was separated into two or more phases was marked with ×.

(2) Confirmation of phase separation structure The curable resin composition was cured at 150 ° C. for 2 hours to produce a cured resin.
The obtained resin cured product was observed with a transmission electron microscope JEM-2100 (manufactured by JEOL Ltd.) to confirm the phase separation structure. When an inhomogeneous phase structure was observed, it was judged that a phase separation structure was formed. As an example, FIG. 1 shows a transmission electron micrograph of a cured resin product produced by curing the curable resin composition obtained in Reference Example 1 under conditions of 150 ° C. for 2 hours. In the transmission electron micrograph shown in FIG. 1, the black portion is a phase composed of (b) a polysiloxane compound, and the white portion is a phase composed of (a) an epoxy resin.
Moreover, about the obtained resin hardened | cured material, sample length 30mm, chuck | zipper space | interval 20mm, frequency 10Hz, temperature increase rate 10 degrees C / min using dynamic viscoelasticity measuring apparatus DVA-200 (made by IT measurement control company). The phase separation structure was confirmed by measuring the glass transition temperature (Tg) under the conditions. When two tan δ peaks were observed, it was judged that a phase separation structure was formed.
From the above two confirmation methods, the case where it was judged that the phase separation structure was formed was marked as ◯, and the case where it was judged that the phase separation structure was not formed was marked as x.

(3) Heat resistance (Tg measurement)
For the cured resin obtained in the same manner as in the above “(2) Confirmation of phase separation structure”, the temperature of the peak on the high temperature side among the tan δ peaks measured in the above “(2) Confirmation of phase separation structure” is set. The glass transition temperature (Tg) was used.

(4) Thermal stress Sample using storage elastic modulus obtained when measuring tan δ peak in “(2) Confirmation of phase separation structure” and TMA analyzer TMA / SS6000 (manufactured by Seiko Instruments Inc.) Thermal stress was defined as the sum of values obtained by multiplying the linear expansion coefficient measured under the conditions of length 20 mm, chuck interval 10 mm, load 5 g, and temperature increase rate 10 ° C./min every 25 ° C. within 1 ° C. .

ADVANTAGE OF THE INVENTION According to this invention, the curable resin composition which can exhibit the outstanding impact resistance and heat resistance after hardening can be provided. Moreover, according to this invention, the resin cured material manufactured by hardening | curing this curable resin composition can be provided.

Claims (3)

(A ) 50 to 90 parts by weight of at least one epoxy resin selected from the group consisting of a dicyclopentadiene type epoxy resin, an anthracene type epoxy resin and a biphenyl type epoxy resin,
(B) 10-50 parts by weight of a polysiloxane compound having a plurality of (meth) acrylic groups and one or more ether groups,
(C) an epoxy resin curing agent, and
(D) containing a radical polymerization initiator ,
The epoxy equivalent of the epoxy resin is 170 or more, the curable resin composition characterized der Rukoto 500 or less. A cured resin product produced by curing the curable resin composition according to claim 1. The cured resin product according to claim 2, which has a phase separation structure.