JP3433878B2 - Epoxy resin composition, film adhesive comprising the same, and method for preparing epoxy resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has excellent storage stability at room temperature and good handleability.
The present invention relates to an epoxy resin composition that is extremely useful as a low-temperature-curing type film adhesive that can be used at 0 ° C., and a method for preparing the same.

[0002]

2. Description of the Related Art A film adhesive is easier to handle than a two-pack type adhesive or a one-pack type paste adhesive and often has excellent performance, so that it is a honeycomb material in the fields of aircraft and construction materials. It is used for the adhesion of the surface material. However, it is difficult to balance handleability (tack, fluidity, etc.) with curing characteristics and storage stability due to the constraint that it must be processed into a film, and there are few materials that satisfy a wide variety of user requirements.

This is because of the following difficulties in designing the resin composition. That is, (1) the curing property and the storage stability are contradictory properties, and (2) the film must be processed at a sufficiently low temperature (to produce a film adhesive having excellent storage stability. In order to form a film at a temperature sufficiently lower than the curing temperature, in the case of a film adhesive that cures at 80 ° C,
It must be processed into a film at at least 50 ° C. ), (3) In many cases, sufficient fluidity at the time of curing is not sufficiently secured by simply selecting a curing agent having a low activity expression temperature, and as a result, sufficient adhesive properties cannot be obtained. It can be cited as the cause.

Further, in order to improve the handleability of the sheet adhesive, it is known to add a high molecular weight epoxy resin to a material which cures at a relatively low temperature of around 80 ° C. Since the mobility of the resin decreases, the reactivity decreases, the curing reaction does not proceed, and sufficient adhesive strength cannot be obtained. Further, a method of simultaneously solving the handling property and the fluidity (for example, JP-A-46-24898, JP-A-53-119939 and JP-A-2-1).
No. 73082), a method of adding an inorganic filler to a resin or a method of adding a rubber component is known. The former reduces adhesive strength and the latter improves handleability, but lowers Tg. However, there is a problem that the use temperature of the adherend is limited. Since these problems have not been solved yet, it has been difficult to cure at 100 ° C or lower and handleability,
A film adhesive having excellent storage stability and adhesive strength has not been developed.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and achieves low-temperature curing type usable at 80 ° C. by satisfying both curing characteristics at low temperature, handleability, storage stability and adhesive strength. It is an object of the present invention to provide an epoxy resin composition that is extremely useful as a film adhesive that can be used in the vicinity of the curing temperature of the adherend, and a method for preparing the same.

[0006]

As a result of intensive studies to solve the above problems, the present invention not only optimizes the composition and amount of the curing agent, but also devises the composition of the base epoxy resin composition. By doing so, they have found that the above problems can be solved. That is, the present invention relates to (A) an epoxy resin 10 containing a non-crosslinked thermoplastic elastomer component.
60% by weight, (B) 5 to 40% by weight of an epoxy resin containing a crosslinked rubber component, and (C) a solid resin having a softening point of 50 ° C. or higher.
Poxy resin 10 to 50% by weight, (D) polyamide resin 2
To 40 parts by weight, based on 100 parts by weight of the resin composition,
(E) 2 to 15 parts by weight of a urea-based epoxy resin curing agent and
(F) Stable at 40 ° C, activated at temperatures below 80 ° C
Resin composition containing 3 to 20 parts by weight of the latent curing catalyst to be obtained
And (A) 10 to 60% by weight of an epoxy resin containing a non-crosslinked thermoplastic elastomer component, (B) 5 to 40% by weight of an epoxy resin containing a crosslinked rubber component,
(C) Softening point is 50 ° C. or higher and epoxy equivalent is 200 to
Solid epoxy resin with a weight of 4000 g / m ²
%, And ( D) polyamide resin 2 to 40% by weight,
To 100 parts by weight of a resin composition containing (E) 2 to 15 parts by weight of a urea-based epoxy resin curing agent and (F) a latent curing catalyst 3 which is stable at 40 ° C. and can be activated at a temperature of 80 ° C. or less. A resin composition containing 20 parts by weight. Each
The first and second aspects of the present invention are obtained by using the above resin composition.
The film-like adhesive to be used is the third gist, (A) 10 to 60% by weight of an epoxy resin containing a non-crosslinked thermoplastic elastomer component, (B) 5 to 40% by weight of an epoxy resin containing a crosslinked rubber component, A resin composition comprising (C) 10 to 50% by weight of a solid epoxy resin having a softening point of 50 ° C. or higher and (D) 2 to 40% by weight of a polyamide resin is mixed at a temperature of the melting point or the softening point of (D) or higher. After making uniform,
The temperature is lowered, and (E) is added to 100 parts by weight of the resin composition.
2 to 15 parts by weight of a urea-based epoxy resin curing agent, and (F) 3 to 20 parts by weight of a latent curing catalyst which is stable at 40 ° C. and can be activated at a temperature of 80 ° C. or less. A fourth gist is a method for preparing a resin composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An important constituent feature of the present invention is that the ratio of an epoxy resin component such as an epoxy resin containing a non-crosslinked thermoplastic elastomer component and an epoxy resin having a crosslinked rubber component to a polyamide resin is 98/2. ~ 60/4
The inventors have found that it is possible to obtain an epoxy resin composition having a good balance of adhesive strength and heat resistance when used in combination at a ratio of 0, and reached the present invention.

The epoxy resin containing the non-crosslinked thermoplastic elastomer as the component (A) is a non-crosslinked thermoplastic elastomer such as a butadiene / acrylonitrile copolymer having a terminal group capable of reacting with the epoxy resin and a styrene / butadiene elastomer. It is obtained by dispersing and reacting a plastic elastomer component in an epoxy resin, and it is preferable from the viewpoint of performance stability that the terminal groups of these elastomer components partially react with the epoxy resin.

The epoxy resin containing the crosslinked rubber as the component (B) is obtained by dispersing a crosslinked rubber component such as butadiene rubber and acrylic rubber in the epoxy resin and then reacting them. These rubber components are used. Similarly to the above-mentioned thermoplastic elastomer component, it is preferable that the terminal group partially reacts with the epoxy resin.

The epoxy resin which is reacted with the non-crosslinked thermoplastic elastomer component or the crosslinked rubber component of the components (A) and (B) is not particularly limited, but is a liquid bisphenol A type epoxy resin or bisphenol F type epoxy resin, bisphenol. The S-type epoxy resin and the novolak-type epoxy resin are particularly preferable from the viewpoint of handleability. An epoxy resin containing such a non-crosslinked thermoplastic elastomer or crosslinked rubber requires a non-crosslinked elastomer component or crosslinked rubber component having a terminal group capable of reacting with the epoxy resin and the epoxy resin at a temperature of 100 to 180 ° C. Although it can be easily obtained by adding a catalyst and reacting, a commercially available resin can be used.

As a modified epoxy resin containing a non-crosslinked thermoplastic elastomer that is commercially available or available as a sample, Epiclon T manufactured by Dainippon Ink and Chemicals, Inc.
SR-960, TSR-930, TSR-601, Epicoat YL-6308, Y of Yuka Shell Epoxy Co., Ltd.
L6347 can be illustrated. Examples of the crosslinked rubber-modified epoxy resin include CX-MN series of Nippon Shokubai Co., Ltd. and crosslinked rubber-modified epoxy resin of Nippon Synthetic Rubber Co., Ltd.

The ratio of the elastomer component and the crosslinked rubber component in these components (A) or (B) is 5 to 50 in each case.
The weight% is suitable, and if necessary, a commercially available modified resin may be diluted with an epoxy resin containing no elastomer component or crosslinked rubber component. Further, the proportion of the elastomer component and the crosslinked rubber component in the resin component of the present invention is appropriately 3 to 30% by weight, more preferably 5 to 20% by weight.

As the component (C) in the present invention, an epoxy resin having a softening point of 50 ° C. or higher is used. By using such an epoxy resin, it becomes possible to control the handleability and fluidity of the entire resin composition without sacrificing the curing characteristics at low temperatures. When the softening point of the epoxy resin as the component (C) is less than 50 ° C., it is difficult to control the handleability of the entire composition at room temperature, which is not preferable.

The epoxy resin used as the component (C) is 1
Although it may be of any kind, two or more kinds of epoxy resins may be mixed and used as required. At this time, the softening points of all the epoxy resins to be mixed do not have to be 50 ° C. or higher, and even if the epoxy resin to be mixed contains an epoxy resin having a softening point of 50 ° C. or lower, the epoxy used as the component (C) It does not matter if the softening point of the resin composition is 50 ° C. or higher. Further, the epoxy equivalent of the entire component (C) is 200 to 4000 g / eq in consideration of the curability.
Is preferred. Particularly preferable epoxy equivalent is 250 to 30.
It is in the range of 00 g / eq.

Examples of the epoxy resin usable as the component (C) include high molecular weight bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, phenol novolac type epoxy resins, and the like. It is not limited to. The following are examples of particularly preferable epoxy resins. Dainippon Ink and Chemicals, Inc .: EXA1514 [epoxy equivalent = 300 g / eq. , Softening point = 75 ° C.] Dainippon Ink and Chemicals, Inc .: HP4032H [epoxy equivalent = 250 g / eq. , Softening point = 70 ° C.] Dainippon Ink and Chemicals, Inc .: EPICLON 152
[Epoxy equivalent = 360 g / eq. , Softening point = 60 ° C.] Dainippon Ink and Chemicals, Inc .: EXA1857 [epoxy equivalent = 250 g / eq. , Softening point = 80 ° C.] Nippon Kayaku Co., Ltd .: EBPS300 [epoxy equivalent = 260 g / eq. , Softening point = 65 ° C.] Dainippon Ink and Chemicals, Inc .: LS120 [epoxy equivalent = 335 g / eq. , Softening point = 80 ° C.] Oiled shell epoxy: Ep1001 [epoxy equivalent = 450 g / eq. , Softening point = 64 ℃]

As the polyamide resin used as the component (D), any polyamide such as crystalline polyamide or amorphous polyamide can be used. Examples of polyamides that can be used in the present invention include nylon 6, nylon 66, nylon 610, nylon 612, nylon 11 and nylon 1.
Examples thereof include crystalline nylon such as 2 and amorphous nylon, or a copolymerized nylon obtained by copolymerizing a large amount of the second component, or by copolymerizing two or more kinds using these, blended products and the like. Is not limited to these.

The polyamide preferably used in the component (D) of the present invention is copolymerized nylon, more preferably alcohol-soluble nylon. When the component (D) is softened or melted during resin preparation, or at least a part thereof is dissolved in the epoxy resin, excellent adhesive strength can be exhibited while maintaining curability at low temperatures.

The same effect can be obtained with a low melting point polyamide. The low melting point in this case refers to a polyamide having a melting point or a softening point below the temperature (about 150 ° C.) for adjusting the epoxy resin component.

The copolymer nylon available as the component (D) is CM4000, CM4001, C manufactured by Toray Industries, Inc.
M8000, CM6000 series, Daicel Chemical Co., Ltd .: Daiamide X1874, N1901 series,
Made by Unitika: Unitika Nylon T-8, C1030,
BASF: 1C, 6A, Henkel Hakusui Co., Ltd. Macromelt JP900, JP901 etc. can be mentioned, but it is not limited to these.

When the component (D) is soluble in the epoxy resin component, the component (D) may have any form and particle size.
When the component (D) does not dissolve in the epoxy resin component, the form of the component (D) is preferably powder. The average particle size of this powder is preferably 150 microns or less, more preferably 100 microns or less. The average particle size in this case means the volume average particle size determined by the centrifugal sedimentation velocity method or the like. If the average particle size exceeds 150 microns,
Adhesion between the surfaces to be adhered cannot be obtained during adhesion, and sufficient adhesion strength cannot be obtained.

The base resin in the epoxy resin composition of the present invention contains the above-mentioned four components as essential components, and the proportion thereof is 10 to 60% by weight of the component (A),
Component (B) is 5-40% by weight, component (C) is 10-50.
%, And the component (D) is 2 to 40% by weight. If the content of the component (A) is less than 10% by weight, sufficient adhesive properties cannot be obtained.
On the other hand, if it exceeds 0% by weight, the adhesive strength is lowered and the Tg is remarkably lowered. If the component (B) is less than 5% by weight (A)
A synergistic effect on the components cannot be obtained and sufficient adhesive strength cannot be obtained. When the amount of the component (B) exceeds 40% by weight, not only the synergistic effect with respect to the added amount decreases but also the adhesive strength decreases. If the amount of component (C) is less than 10% by weight, the resin composition will have poor handleability, and if it exceeds 50% by weight, the mobility of the resin composition will decrease and the curability at 80 ° C will deteriorate.

The base resin in the present invention is (A)
The component (D) is an essential component, but other epoxy resins may be used in combination. As the other epoxy resin, an epoxy resin such as an elastomer, a bisphenol A type epoxy resin which is not modified with a crosslinked rubber, a bisphenol S type epoxy resin, a bisphenol F type epoxy resin, a glycidyl amine type epoxy resin can be used. Although it can be appropriately used depending on the purpose, its ratio is preferably within 30% of the whole epoxy resin composition in the present invention.

As the curing component in the present invention, a urea type epoxy resin curing agent (E) and a latent curing catalyst (E) are used in combination. Examples of the urea-based epoxy resin curing agent (E) include those represented by the following structural formula.

[0024]

[Chemical 1]

[0025]

[Chemical 2]

The latent hardener (F) that is stable at 40 ° C. and can be activated at a temperature of 80 ° C. or lower is stable at 40 ° C. among latent hardeners such as microcapsule type and amine adduct type. What can be activated at a temperature of 80 ° C. or lower is used. Commercially available latent hardeners that meet these conditions alone are PN of Ajinomoto Co., Inc.
-23, HX-3721, HX-372 of Asahi Kasei Corporation
2, H3615, 4003, 4070 of ACR Co. can be exemplified. These may be used alone or in combination of two or more.

The mixing ratio of these curing agents is 2 to 15 parts by weight of (E) and 3 to 20 parts by weight of (F) with respect to 100 parts by weight of the epoxy resin compositions (A) to (D) as the base. It is a department. If the amount used is less than this range, the curing reaction will not proceed sufficiently and the adhesive strength will not be obtained when cured at 80 ° C. Further, even if it is used beyond this range, not only the curing characteristics reach a ceiling, but also storage stability and adhesive strength deteriorate,
Not preferable. More preferable amount of the curing agent system is (E)
Is 5 to 10 parts by weight, and (F) is 5 to 15 parts by weight.

The combined use of the component (E) and the component (F) is the second important requirement of the present invention. If the curing catalyst is simply cured at 80 ° C., even if the latent curing catalyst is used alone, it is possible if the epoxy equivalent is sufficiently used, but sufficient strength cannot be obtained in terms of adhesive strength. On the other hand, when the urea-based epoxy resin curing agent is used in combination, sufficient adhesive strength can be obtained even with a smaller amount of the curing agent used. The mechanism of this combined curing has not been fully clarified yet, but it is presumed that the crosslinked structure formed by the combined use of the curing agents is different from that of the latent catalyst alone.

Further, a promoter may be added to the above epoxy resin curing agent system. In particular, the aromatic amine compound can accelerate the curing reaction when used in combination with the latent curing agent. Examples of the amine compound acting as a cocatalyst include aromatic diamines such as metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and diaminodiethyldiphenylmethane, but are not limited thereto.

In the epoxy resin composition of the present invention, in addition to the above components, fillers such as calcium carbonate and talc, flame retardants, pigments and the like can be appropriately used according to the purpose.
Further, when used as a film adhesive, glass, polyester, nylon or other non-woven fabric, woven material or the like used as a carrier material may of course be contained. In order to maximize the characteristics of the epoxy resin composition of the present invention, the components (A) to (D) are mixed at a temperature equal to or higher than the melting point or softening point of the component (D) to make them uniform, and then the temperature is lowered.
It is preferable to add the components (E) and (F) to the resin composition. Curing at low temperature, which is a feature of the epoxy resin composition of the present invention, by raising the temperature of the resin composition to which the component (D) is added to a temperature equal to or higher than the melting point or softening point of the component (D) to make it uniform. While exhibiting excellent properties, it exhibits excellent adhesive strength and can be sufficiently adhered to a flexible material such as a foam. The temperature at which the components (E) and (F) are added is a temperature at which the activity of the component (F) is not sufficiently expressed, and the components (A) to (D) are mixed with the components (E) and (F). The temperature that can be achieved in a short time may be determined from the curing characteristics of the component (F).

[0031]

EXAMPLES The present invention will be described in more detail by way of examples. All parts in the examples are parts by weight, and the abbreviations used are as follows. YL6308; reaction product of styrene / butadiene elastomer and bisphenol A type liquid epoxy resin. Estimated elastomer content = 10% (Okaka Shell Epoxy Co., Ltd.) BPA328; Reaction product of acrylic rubber having a crosslinked structure and bisphenol A type liquid epoxy resin. Estimated rubber content = 20% (Nippon Shokubai Co., Ltd.) BPF307; a reaction product of an acrylic rubber having a crosslinked structure and a bisphenol F type liquid epoxy resin. Estimated rubber content = 20% (Nippon Shokubai Co., Ltd.) Ep828; Epicoat 828 bisphenol A type epoxy resin (Okaka Shell Epoxy Co., Ltd.) Ep1001; Epicoat 1001 solid epoxy resin,
Softening point = 70 ° C., epoxy equivalent = 480 g / eq (Okaka Shell Epoxy Co., Ltd.) Ep4005; Epicoat 4005 solid epoxy resin,
Softening point = 90 ° C., epoxy equivalent = 1100 g / eq (Okaka Shell Epoxy Co., Ltd.) EXA1514; Bisphenol S type epoxy resin, softening point = 75 ° C., epoxy equivalent = 300 g / eq (Dainippon Ink and Chemicals) N740; EPICLON N740 phenol novolac type epoxy resin, semi-solid (Dainippon Ink and Chemicals Incorporated) PN-23; amine adduct type latent curing agent (Ajinomoto Co., Inc.) HX-3722; microcapsule type latent curing agent (Asahi Kasei Co., Ltd. )) JP901; Alcohol-soluble nylon (Henkel Hakusui Co., Ltd.) D250; Copolyamide (Daicel Huls KK) PDMU; 3-Phenyl-1,1-dimethylurea (Omicure 94, ACIJapan Ltd.) DCMU; 3- ( 3,4-Dichlorophenyl) -1,1-
Dimethylurea (DUMU99, Hodogaya Chemical Co., Ltd.) DDS: 4,4′-diaminodiphenylsulfone (S
EIKA & COMPANY, LTD. )

Each evaluation in Examples and Comparative Examples was carried out by the following methods. The handleability was evaluated by whether or not the top film (protective film) could be released when the resin composition was formed into a film (◯: good, ×: bad). The heat resistance of the resin composition is determined by Mechanical Thermo
1 Analysis (Tanδmax) was used for evaluation.
The evaluation of the adhesive strength is based on JIS 6850 (1976) "Test method for tensile shear adhesive strength of adhesive", and an aluminum plate (A202) which is sandblasted on an adherend.
4P-T3). The evaluation of the adhesive strength with the foam is based on ASTM-C-297-76 (flatwise tensile test), and a polyvinyl chloride foam Kreguecel # 100 manufactured by Kanegafuchi Chemical Industry Co., Ltd. is used as the foam. I went. What was broken inside the foam was marked with ◯. Storage stability is 2 after the preparation when the resin composition is left at room temperature.
The time required for the viscosity to be doubled was evaluated. The curing conditions of the above resin were 80 ° C. × 3 hours.

[Example 1] 10 parts of TSR960 as the component (A), 40 parts of BPA328 as the component (B), and Ep10 as the component (C).
30 parts of 01, 15 parts of JP601 as the component (D),
5 parts of Ep828 and Ep828 were mixed at 150 ° C and then cooled to 60 ° C. To this, 10 parts of Ep828, which was previously made into a paste by three rolls, 7 parts of DCMU, PN-23
A mixture of 10 parts and 2 parts of DDS was added, and the mixture was stirred and mixed until it became uniform to obtain an epoxy resin composition of the present invention. Then, this epoxy resin composition is heated to 50 ° C. to form a film having a thickness of 150 μm and a basis weight of 20 g / m 2.
The polyethylene non-woven fabric of ² was laminated to form a film-like adhesive, and the handling property, adhesive strength and the like were evaluated. The results are shown in Table 1.

[Examples 2 to 12] The components of the epoxy resin and the curing agent used and the compounding ratios thereof were changed as shown in Table 1 and evaluated in the same manner as in Example 1. The evaluation results are also shown in Table 1.

[0035]

[Table 1]

[Comparative Examples 1 to 11] Epoxy resin components used and their compounding ratios were changed as shown in Table 2 and evaluated in the same manner as in Example 1. The evaluation results are also shown in Table 2.

[0037]

[Table 2]

[0038]

The epoxy resin composition of the present invention can be cured at a low temperature in a short period of time, has excellent handleability at room temperature and storage stability, and has a high adhesive strength. It is extremely useful for applications such as Furthermore, the epoxy resin composition obtained by the preparation method of the present invention has excellent adhesiveness to flexible materials such as foams.

Continuation of front page (51) Int.Cl. ⁷ identification code FI C08L 77:00 (56) References JP-A-8-59793 (JP, A) JP-A-8-20629 (JP, A) JP-A 7-309930 (JP, A) JP 9-316302 (JP, A) JP 7-157534 (JP, A) JP 7-157535 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 63/00-63/10 C08G 59/00-59/72 C09J 163/00-163/10 C09J 7/00-7/04

Claims (5)

(57) [Claims] 1. (A) 10 to 60% by weight of an epoxy resin containing a non-crosslinked thermoplastic elastomer component, (B) 5 to 40% by weight of an epoxy resin containing a crosslinked rubber component,
(C) Solid epoxy resins 10 to 5 having a softening point of 50 ° C. or higher
0% by weight, (D) polyamide resin 2 to 40% by weight
(E) urea-based epoxy resin to 100 parts by weight of the resin composition.
Stable with 2 to 15 parts by weight of resin curing agent and (F) 40 ° C
And a latent curing catalyst that can be activated at a temperature of 80 ° C. or less
A resin composition containing 3 to 20 parts by weight. 2. (A) 10 to 60% by weight of an epoxy resin containing a non-crosslinked thermoplastic elastomer component, (B) 5 to 40% by weight of an epoxy resin containing a crosslinked rubber component,
(C) Softening point is 50 ° C. or higher and epoxy equivalent is 200 to
Solid epoxy resin with a weight of 4000 g / m ²
%, And ( D) polyamide resin 2 to 40% by weight,
To 100 parts by weight of a resin composition containing (E) 2 to 15 parts by weight of a urea-based epoxy resin curing agent and (F) a latent curing catalyst 3 which is stable at 40 ° C. and can be activated at a temperature of 80 ° C. or less. A resin composition containing 20 parts by weight. 3. The (E) urea-based epoxy resin curing agent is as follows:
A compound represented by any of the structural formulas of
Or the resin composition described in 2. [Chemical 1] [Chemical 2] 4. A film adhesive made of the resin composition according to claim 1 . 5. ( A) Non-crosslinked thermoplastic elastomer composition
Epoxy resin containing 10 to 60% by weight, (B) rack
5-40% by weight of an epoxy resin containing a bridge rubber component,
(C) Solid epoxy resins 10 to 5 having a softening point of 50 ° C. or higher
0% by weight and (D) polyamide resin 2 to 40% by weight?
A resin composition consisting of (D) at a temperature above the melting point or softening point.
The resin composition 1 is mixed by a certain degree to make it uniform, and then cooled.
(E) urea-based epoxy resin curing agent based on 100 parts by weight
2 to 15 parts by weight, and (F) stable at 40 ° C., 8
Latent curing catalyst 3 to 20 that can be activated at a temperature of 0 ° C. or less
Epoxy resin composition characterized by blending parts by weight
Preparation method of.