JPS62100518A - Epoxy resin composition for use in prepreg - Google Patents

Abstract

PURPOSE:To provide the titled composition ensuring its storage of ambient temperatures for a long period, curable at relatively low temperatures, comprising an epoxy resin and, as the curing system, a combination of an imidazole derivative of specific structure and dicyandiamide. CONSTITUTION:The objective composition can be obtained by incorporating (A) an epoxy resin (e.g., bisphenol A-epichlorohydrin resin) with (B) as the curing system, a combination of (i) an imidazole derivative of formula (n is 10-20; R<1>-R<3> are each H, lower alkyl or aryl) and (ii) dicyandiamide followed by stirring. The total amount of the components i and ii to be used is preferably 4-10pts. by wt. based on 100pts. by wt. of the component A.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an epoxy resin composition for prepreg.

(Prior art and its problems) Conventionally, as an epoxy lubricant composition for prepreg, for example, (1) a bisphenol type or 17 novolac type epoxy resin and a lower alkyl group-substituted imitazole compound such as 2-1/tylimidazole. A composition consisting of (
2) Bisphenol-type or novolak-type epoxy resins, dianne, niamide, and 2,4.6-1-lith (
Dimethyl-amino)methylphenol, borohydride i 4 or 3-(3,4-dichloro'1phenyl)-
Compositions consisting of 1,1-dimethylurea are used.

However, the above-mentioned (1) (i) acid compounds have poor storage stability, and, for example, when storing prepregs made by impregnating glass cloth, carbon cloth, etc. with the composition at room temperature or encasing them, it is difficult to prepare them. The same performance as immediately after is maintained for only a few days at most; after that time, the performance not only deteriorates significantly, but in some cases, it may become unusable. However, during storage or transportation, it is necessary to use a cooling medium such as dry ice at a low temperature, resulting in poor workability and economic efficiency.

In addition, the composition (2) described above has a slightly longer performance retention period (about several weeks) than the composition (1), but the curing heating temperature during curing is a high temperature of 130°C or higher. Not only that, but also post-heating is required. Since such high temperature curing is required, for example, ABS
When obtaining an integrally molded product with a molded product, there is a disadvantage that the ABS resin molded product is deformed. For this reason, when compounding or integrating, explode separately,
It is necessary to use adhesives to bond and integrate, which is poor in workability, and requires thermal energy to raise the temperature, making it less economical.

On the other hand, as an epoxy resin varnish with excellent pot life, workability, chemical resistance, etc., for example, 45 to 87 parts by weight of an epoxy resin consisting of 60 to 95 parts by weight of solid epoxy resin and 40 to 5 parts by weight of liquid epoxy resin is used. parts and 10 to 4 parts of solvent
5 parts by weight and the general formula % formula % alkyl or diamino-8-triacylalkyl group, R2: H atom, argyl or aryl group, R3: H atom or alkyl group, R,: H atom or alkyl group). The imidazole derivative and dicyandiamide shown in 9:
An epoxy resin varnish characterized by containing 3 to 10 parts by weight of a curing agent in a ratio of 1 to 1:9 has been proposed (see Japanese Patent Publication No. 60-3113).

However, this composition also has poor storage stability at room temperature, and therefore must be used several times after preparation, and in order to be usable over a long period of time, it must be stored at a low temperature. It is necessary to.

(Objects, Structures, and Effects of the Invention) The present invention aims to overcome the drawbacks of conventional epoxy resin compositions as described above, and to provide an epoxy resin composition that is particularly suitable for producing prepregs. be.

Non-inventions are as follows.

Of course, the curing system has the following structural formula (where n is an integer from 10 to 20, and R1, R2, and R3 are the same or different). 1. An Epoquin resin composition for prepreg, comprising an imidazole derivative having a hydrogen atom, a lower alkyl group, or an aryl group, and dicyandiamide.

Uninvented prepreg epoxy tl ll'i'f'
According to the 1rfA composition, the following effects can be obtained.

(1) It can be stored stably for a long period of time without any change in performance at room temperature, so there is no need to use a cooling medium such as dry ice during storage or storage, unlike with Juto products.

(2) Conventional compositions of this type had a high τ island of 130°C or more during curing, and required post-heating, resulting in poor economic efficiency and workability. 1.
f: The composition of the invention is relatively (≧low temperature (90-100°C)
You can inflict a hard 1 hit with this.

G) A because it can be cured at a relatively low temperature
The plastic molded product will not be deformed by heat even when it is integrated into a composite with a plastic molded product that has a low electric power due to the softening properties of BS resin and the like.

As the epoxy resin targeted by the invention, all those conventionally used in this type of field can be used, and specifically, brominated epoxy resin, epoxy novolac resin, bisphenol A. Examples include epichlorohydrin resins, polyfunctional epoxy resins, aliphatic EVO'A resins, l-cyclic epoxy resins, and urethane-modified epoxy resins. These may be either liquid or solid.

Among the epoxy resins listed above, bisphenol A-
It is preferable to use epichlorohydrin resin, evoquin novorasoc resin, and polyfunctional epoxy resin alone or in combination.

Next, the imidazole derivative used in the present invention has the following formula: is a group selected from aryl groups such as groups, and this R'+R2+n is 10 to 20
The number of rods is 6, and the value of (σ11) is 11.13 with the invention.
．． 15 or 17 words11. stomach. If the value of n is less than 10, the storage stability will be poor, and if it exceeds 20, there will be no problem with storage stability, but it will require a high temperature (150℃ or higher) for curing. Become.

For such imidazole derivatives, 1. t’.

You can list various compounds by selecting any one type of R2+ R3 and +1i of n, but,
Among them, the compounds shown in F are suitable for Gif.

++ Furthermore, dicyandiamide is represented by the following formula % and is a monoclinic crystal compound with a specific gravity of 1.40 (at 25°C). It is synthesized by polymerization, cooling, and transfer contact.

The use of the curing system in the present invention is limited to the total amount of imidazole derivatives and dicyandiamide.
1 to 20 trenches for the 0-fold end, preferably 4 to 10 trenches
Good to use in the range of heavy weight,.

If the amount of the curing system used is less than 1 part by weight, the storage stability will be good, but it will require a slightly higher temperature and a longer time for curing. Although curing can be completed in a short time, storage stability becomes poor.

Further, the ratio of the imicuzol derivative to dicyandiamide used is preferably 4:1 to 1:4 (weight ratio). If the proportion of the imidazole derivative is too high, the storage stability will be poor, and if it is too low, it will take a long time to cure.

The composition of the present invention is prepared by uniformly kneading the composition in the upper and lower grades. ) As a general rule, there is no problem in adding diluents (organic ingredients, etc.), plasticizers, light value agents, flame retardants, pigments, etc.Four ways to obtain prepreg11゜The base material used is carbon fiber,
Glass fibers, polyamide fibers, woven fabrics of these fibers, paper, and the like are used.

τ Using the composition of the present invention ~ 1) Pregres rr 4%,'
: For 5, the liquid material of ①substitute ① or ：・zu1
．． All you have to do is immerse the substrate in the liquid, or apply it to the liquid or supernatant, and add the desired amount of the l'11 component.

(Practice 191] and Comparison JV example) The examples and comparative examples are particularly interesting.

In addition, all the parts in the column are heavy items.

Great, Ebogi 7.1 for prepreg! "t1 Grease fluid or film a little spray ↑ Grease fluid,, < := Muff ()
Created using v t, 1. Each of the prepared prepregs was prepared as follows: Immediately after the prepared epoxy resin for prepreg was prepared, it was measured according to JIS C21,04 (curing heating temperature: 150°C).

(2) After storage at room temperature for 30 days: The epoxy resins for prepreg prepared in Examples and Comparative Examples were placed in all containers and stored at room temperature for 30 days without sealing, and then measured according to JIS C2104 (curing heating temperature 150°C).

[Pot life of prepreg at 25°C] The prepreg was left in a room at 25°C, and the number of days during which it could maintain the same physical properties (curing properties, etc.) as immediately after production was measured.

[Curing time at 100° C.] The time required for the prepreg to harden completely and reliably at 100° C. immediately after production was measured.

[Lamination integration with plastic molded products] A square plate made of ABS Meigetsu, 2 mm thick and 100 strips on a side, was laminated with 1/15 gold sheets of blib on each side, heated,
After pressurizing (temperature 100°C, pressure 25 K9/J, time 30 minutes), it was cooled to room temperature/ζ.

In addition to examining the adhesion between the prepreg and the ABS resin plate, the state of change in the ABS seal plate was visually observed at 7't-0. 70 parts of epoxy it 1IEi (trade name Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.), 10 parts of epoxy resin (trade name Epicoat 1001, manufactured by Yuka Shell Epoxy Co., Ltd.) and 20 parts of epoxy resin (trade name Epicoat 1001, manufactured by Yuka Shell Epoxy Co., Ltd.) were added to 755 parts of methyl ethyl keto. In addition, 4 parts of dicyandiamide was dissolved in 55 parts of methanol. 7 methanol solution of dicyandiamide was added to the methyl ethyl ketone solution of the epoxy resin and mixed uniformly.

Next, 2 g of an imidazole derivative (trade name: CUREZOL CIIZI, manufactured by Shikoku Kasei Co., Ltd.) was added to this mixed solution and sufficiently stirred to prepare an epoxy resin liquid for prepreg.

This resin liquid was impregnated into a commercially available glass cloth at a temperature of 1:30.
Drying was performed at ℃ for 2 minutes and 30 seconds to produce a prepreg. The stool fat content (as solid content) in the prepreg was about 38% by weight.

When the various physical properties of the epoxy resin liquid for prepreg prepared above and the prepreg obtained by impregnating glass cloth with this resin liquid were examined, the following results were obtained.

Table 1) Evoquin Resin for Bribble G After Preparation 1α, 1
Gelation time of minutes 10 seconds 1 □ I 1 30:I at room temperature
: After storage for days: 1 minute 10
seconds □ba 1 Prepreg I3T3 time at 125°C 'th - 15th day':: Curing at 100°C J, i
30 minutes □ 1 1 □, e1-
, Oh.

1. According to this, the prepreg obtained by impregnating the resin composition prepared in Example 1 has a usable life of 14 to 15 days, and the usable life of the prepreg obtained by impregnating it with the resin composition prepared in Example 1 is 14 to 15 days. It can be seen that the prepreg impregnated with the inventive resin composition exhibits excellent storage stability for a longer time than 2 to 3 days.

Comparative Example 1 An epoxy resin liquid metal for prepreg was prepared in the same manner as in Example 1 except that dicyandiamide was not used at all in the formulation shown in Example 1. A prepreg using this metal was also produced. When various physical properties of the epoxy resin liquid for prepreg and the prepreg were investigated, the following results were obtained.

Table 2: Pot life of Gripreg at 25°C, 12~
3 days]! −−−1−Sheep−−−−−−111～−
---'-11(4"(7)41D/dWM'F=:
1 good 1 fruit, 1 row 2 e hoki/jutsuji (() name craft vinyl
--1 5 4. 1Fil conversion epoxy/manufactured by company) 70 copies, epoxy,... 1 shochu 11! 'i (product name,,
:r-Hiko・) 828, Yukakeneno (・Evo A.

) 10 parts and Evokin resin (trade name: Evojt 1)
Mix 20 parts of 20 parts of dicyan, 4 parts of 2-amide, and 4 parts of 2-\p-decylimidazole (trade name: Gyu7Azo"' CHI Z), manufactured by Shikoku Kasei Co., Ltd.) and heat. The resulting mixture was coated on release paper, and after cooling, an epoxy resin film for prepreg was coated.

This film was heat-pressed onto glass cloth A'f L.
71 prepreg was manufactured. This resin gold 'h-5
The permeability (as a solid content) was 35 times.

The various physical properties of the epoxy resin liquid for prepreg and prepreg obtained above were investigated, and the results shown below were obtained.

Table 3 1 Evo 1 for prepreg Immediately after preparation 1 minute: j □ After storage
11■----------------
−−11−−−−−−−−−≠〜−−−−111−−
-----------1 Prepreg pot life at 25°C 1 14-15 days 1100, CVCkk
'j'6@i(t#l'q'l l
309'1 -------1--,
--, ---------m--1--1--------
-B1 1 No change observed 1 Comparative Examples 2 to 5 Same composition except that an imidazole derivative and a compound represented by the formula L2, in which R' is a group as shown in the table below, were used. An epoxy resin liquid for prepreg was prepared by treating the same in the same manner.

In addition, a prepreg of λ&l~ was produced using this resin liquid kegara and 2 scross.

Ebogi 7 for prepreg obtained above Eil Pilgrimage Night Support 7! - When the three-way physical properties of Brifulleg were investigated, - the results shown above were obtained.

Examples 3 to 6 As an imidazole transparent conductor, instead of the product name Ki, -1-Azole IZ (manufactured by Shikoku Kasei Co., Ltd.), Imidazole diluted and exclusive 2 Tozenbin LPI, which is a bag like the one shown in the picture, was used. In contrast to Example 2 above, a material consisting of '11 bites was treated in the same manner as in Actual Example 2 to obtain an epoxy/mei resin film for prepreg.

In addition, this film 1- was thermocompression-bonded to glass cloth in the same manner as in Example 2 to produce a prepreg (each had an Ike 1 fat content of about 35 weights (.1-thread).

- When various physical properties were investigated for the prepreg and the Evokin resin film for prepreg obtained by the method, the following results were obtained.

Claims (1)

[Claims] In an epoxy resin composition for prepregs consisting of an epoxy resin and its curing system, the curing system has the following structural formula ▲ Numerical formula, chemical formula, table, etc. ▼ (where n is an integer from 10 to 20) , R^1, R^2, R^
3 is the same or different and is a hydrogen atom, a lower alkyl group,
Or represents an aryl group. ) An epoxy resin composition for prepreg, comprising an imidazole derivative having the following formula and dicyandiamide.