JPH04153252A - Matrix resin composition - Google Patents

Abstract

PURPOSE:To obtain a matrix resin composition for a fiber-reinforced composite material improved in resin flow resistance during curing and molding, moldability, stability of the weight of a molding an workability by adding an intramolecularly epoxidized polybutadiene to a resin composition. CONSTITUTION:An intramolecularly epoxidized polybutadiene as a modified is added to a composition comprising an epoxy resin, e.g. a mixture of bisphenol A epoxy resin with a phenol novolac epoxy resin, a curing agent such as dicyandiamide and a catalyst such as 3-(3,4-dichlorophenyl)-1,1-dimethylurea to obtain an epoxy resin for a prepreg containing carbon fibers or the like. The amount of the modifier added is 1-30 pts.wt., desirably 3-20 pts.wt. per 100 pts.wt. total weight of the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a matrix resin composition for fiber reinforced composite materials.

More specifically, the present invention provides a prepreg matrix that has excellent moldability, storage stability, and particularly excellent resin flow resistance during mold curing, which is necessary to obtain a molded product with stable weight, and has excellent moldability. The present invention relates to a resin composition.

(Prior Art) In recent years, carbon fiber (hereinafter abbreviated as CF) has been used in the form of composites with resins, so-called prepregs, by taking advantage of its light weight, high strength, and high modulus of elasticity, and is being used in golf shafts, fishing rods, and tennis rods, for example. Carbon fiber reinforced plastics (hereinafter referred to as C
The field of use of FRP (abbreviated as FRP) continues to expand.

Resin compositions for prepreg used to create such CFRP include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, Talesol novolac type epoxy resin, etc., which are glycidyl ether type epoxy resins. However, mixtures of cycloaliphatic epoxy resins, glycidyl ester type epoxy resins, glycidylamine type epoxy resins, heterocyclic epoxy resins, etc. are also known.

In addition, as curing agents and catalysts, amines, acid anhydrides,
Polyamide resins and imidazoles are known, and are appropriately added in a predetermined amount to the above-mentioned epoxy resin composition.

Now, CFRP produced using a resin composition obtained as a mixture of these can be a molded product with well-balanced physical properties if the molding conditions are appropriate, but these mixtures generally have problems during curing molding. The viscosity decreases significantly as the temperature rises, and at high temperatures and under pressure, the resin becomes extremely prone to flow, which causes the weight of the molded product obtained to fall below the set value and not to meet the product specifications. If this occurs or a localized flow occurs, local structural defects such as voids will be induced.

Furthermore, in the case of a molded article with a complicated shape, if the resin flow is large and its speed is too fast, the CF will not follow the inner wall surface of the mold well, causing the CF to wrinkle and form surface defects.

On the other hand, from the viewpoint of workability, the flowed resin turns into flakes and adheres to the molded product, and the larger the amount, the more complicated the process of removing the flakes, which significantly reduces workability.

That is, the matrix resin composition for prepreg is required to have good weight stability and moldability of molded products, and also good workability.

For such required characteristics, for example, Japanese Patent Application Laid-Open No. 62-169
As seen in JP-A No. 829 and JP-A-1-161040, a method of adding a modifier is disclosed as an attempt to suppress a decrease in the viscosity of a matrix resin. In this method, it is important that the modifier to be added has a smaller change in viscosity with respect to temperature change than the epoxy resin, and generally higher molecular weight polymers are the preferred choice.

In this case, the key points in selecting a modifier are matrix resin,
In other words, it must have good compatibility with the above-mentioned epoxy resin. For example, if the compatibility is extremely poor, not only will the epoxy resin not be modified, but it will remain as a foreign substance, resulting in the hardening of the cured product. It is clear that it significantly reduces mechanical properties and cannot be used as a modifier. Next, in cases where compatibility is slightly poor, that is, microphase separation occurs, the effect of improving resin flow resistance is not recognized. Although it cannot be added, it does have a considerable influence on the mechanical properties of the cured product, and the amount added is naturally limited. Additionally, as the curing of the epoxy resin progresses, its compatibility with the modifier often tends to decrease (changes in the curing conditions will result in changes in the physical properties of the molded product, leading to a decrease in the stability of product specifications). undesirable from this point of view.

Therefore, it is desirable that the modifier has complete compatibility with the epoxy resin on the molecular order, and that phase separation does not occur as curing progresses. However, it is difficult to avoid phase separation as the curing progresses, and the next point is to suppress the deterioration of mechanical properties of the phase-separated structure.

(Problem N to be solved by the invention) The present inventors have completed the present invention as a result of intensive studies, and the purpose thereof is to solve problems related to the improvement of such epoxy resin compositions. By improving lysine flow resistance during curing molding, moldability,
The present invention provides an excellent matrix resin composition that can improve the weight stability and workability of molded articles.

(Means for Solving the Problems) That is, the present invention is an epoxy resin composition for prepregs containing intramolecularly epoxidized polyphtadiene.

The present invention will be explained in detail below.

Here, as the epoxy resin, a mixture of a phenol novolac type epoxy resin, a Talesol novolank type epoxy resin, and a bisphenol A type epoxy resin is preferable.As such a phenol novolac type epoxy resin, for example, Epicote 152.154 ( (manufactured by Yuka Shell Epoxy Co., Ltd.), DEN431.438.43
9.485 (manufactured by Dow Chemical Company), EPN113B, 1
139 (manufactured by Ciba Geigy), N730.738.74
Examples include 0.770.775.865.870.510 (manufactured by Dainippon Ink and Chemicals), EPPN201 (manufactured by Nippon Tohoku Co., Ltd.), and YDPN601.602 (manufactured by Tobu Kasei Co., Ltd.).

As Talesol novolac type epoxy resin, ECN
273.280.299 (manufactured by Asahi Kasei Industries), EP18
0 (manufactured by Yuka Shell Epoxy Co., Ltd.), N665.670.6
73.680.690.695 (manufactured by Dainippon Ink Chemical Co., Ltd. L ECN273.103.104 (manufactured by Nippon Tohoku Co., Ltd.), ECN1235.1273.1280.1299
(manufactured by Ciba Geigy), YDCN701.702.7
03.704 (manufactured by Tobu Kasei Co., Ltd.), etc.

As a bisphenol A type epoxy resin, AER33
0,331,661,664,667,669 (manufactured by Asahi Kasei Industries, Ltd.), EP827.828.834.1001.
1002.1004.1O07,1009 (manufactured by Yuka Shell Epoxy Co., Ltd.), DER331,332,662,66
3u (manufactured by Dow Chemical Company), CY2O5,230,2
32,221,257,252,255,250,26
0,280 (manufactured by Ciba Geigy), Epicron 840.
850.855.860, 1050.3050.405
0.7050 (manufactured by Dainippon Ink Chemical Co., Ltd.), YD115
．． 115CA, 117.121.127.128.12
8CA, 12BS, 134.001Z, 011,012
．． 014.014ES.

017.019.020.002 (manufactured by Tobu Kasei Co., Ltd.), etc.

Here, as the novolac type epoxy resin, either a phenol novolac type epoxy resin or a cresol novolac type epoxy resin may be used, but since both have relatively small epoxy equivalents, the crosslinking density of the cured molded product will be high. As a result, although it exhibits high heat resistance and high elastic modulus, it exhibits brittle properties due to low elongation.

On the other hand, since bisphenol A type epoxy resins have various epoxy equivalents, it is possible to control the elongation by appropriately blending them.

From this point of view, the blending amount of the novolac type epoxy resin is 20 to 80 parts by weight, more preferably 40 to 60 parts by weight, out of 100 parts by weight of the total weight, while the blending amount of the bisphenol A type epoxy resin is This corresponds to the total amount excluding the blended amount of mold epoxy resin. In addition, when blending bisphenol A type epoxy resin, in order to control the surface tackiness of the prepreg, a relatively high molecular weight material that is solid at room temperature and a relatively low molecular weight material that is liquid are appropriately blended. can be taken.

Next, curing agents and catalysts are used in sports and leisure applications.
Since 130"C curing is the mainstream, dicyancidiamide among amines is preferable as a curing agent, and 3-(3,4-dichlorophenyl)-1,1-N is preferable as a catalyst.
Urea compounds such as dimethylurea and 3-phenyl-1,1-N dimethylurea, imidazole derivatives, and the like are preferable.

Now, the key point of the present invention is to use intramolecularly epoxidized polybutadiene as a modifier in such an epoxy resin composition.

Compounds with various structures have been obtained as intramolecularly epoxidized polybutadiene, but as a result of intensive studies by the present inventors, the side chain carbon double bond of 1,2-addition type polybutadiene was epoxidized. The inventors have discovered that the above-mentioned modified hardening is remarkable in the compound represented by the formula, leading to the present invention.

-4GHz-CB-CHz-CH-CHz-CH←T-
(JI=CHz CH=C)l! CB-CH Engineering\1 As a commercially available product of such intramolecularly epoxidized polybutadiene, BF-1000 (manufactured by Adeka Argus) can be used. Further, intramolecularly epoxidized polybutadiene using 1,4-addition type polybutadiene can also be used, and a commercially available product includes R-45EPI (manufactured by Nagase Kasei Co., Ltd.).

The characteristics of intramolecularly epoxidized polybutadiene are listed below.

First, regarding compatibility with epoxy resins, unmodified polybutadiene has extremely poor compatibility, but by epoxidizing a portion of the side chain vinyl groups, the polarity of the molecule increases, resulting in a solubility parameter similar to that of epoxy resins. This makes it possible to provide extremely good compatibility. The solubility parameter indicating good compatibility with the epoxy resin is 9.5 to 11.5, more preferably 1
The modified vinyl group in the epoxidized polybutadiene molecule is 0 to 11 and is 5 to 50% of the unmodified epoxy group.
is desirable, more preferably 10 to 30%.

Next, this intramolecularly epoxidized polybutadiene has a characteristic that the viscosity change with temperature changes is small compared to various epoxy resins, and these mixed resins also have a small viscosity change with temperature changes, and can be cured and molded. As a result of increasing the optimum viscosity level, it is possible to reduce the amount of resin flow.

Another noteworthy effect is that the fluidity of the fibers in the matrix resin during molding is significantly improved, resulting in better alignment of the fibers on the wall of the molding die, making it possible to significantly improve moldability. It is.

Suppression of resin outflow, improvement of fiber fluidity, and
It is extremely surprising that these contradictory properties are compatible, and it is also judged to have extremely high industrial utility value. In addition, this intramolecular epoxidized polybutadiene is
It is also possible to use together with already known modifiers such as polyvinyl formal, phenoxy resin, dimer acid diglycidyl ester type epoxy resin, etc.

Conventionally used modifiers either have no reactivity with epoxy resins or only have a reactive functional group at the end of the molecular chain, and a decrease in heat resistance is unavoidable as the amount added increases. there were.

Furthermore, if microphase separation occurs as the curing reaction progresses, mechanical properties may deteriorate, so the amount added is naturally limited.

On the other hand, the intramolecularly epoxidized polybutadiene of the present invention has an epoxy group in the molecule, so it is incorporated into the crosslinked structure of the epoxy resin after curing, suppressing the extreme drop in heat resistance even when the amount added is increased. It becomes possible to do so.

Depending on the curing conditions or the type of epoxy resin, even if the phase separation reaction precedes the crosslinking reaction during curing and molding, there may be a difference between the epoxy resin and intramolecular epoxidized polybutadiene in the final cured product. Because chemical bonds are formed, there are no structural defects that degrade mechanical properties, and the relatively soft domain of intramolecular epoxidized polybutadiene becomes a part that absorbs energy when subjected to impact, resulting in improved durability. This also results in the characteristic of improved impact resistance.

Furthermore, since the intramolecularly epoxidized polybutadiene has a viscous liquid state at room temperature, the drapeability of the obtained prepreg increases and the lamination workability is significantly improved.

The amount of the intramolecularly epoxidized polybutadiene added is 1 to 30 parts by weight, more preferably 3 to 20 parts by weight, based on 100 parts by weight of the total resin weight.

The fiber reinforcing materials used in the present invention include carbon 111m, glass fiber, organic high elastic wire II (for example, polyaramid fiber, etc.), silicon carbide fiber, alumina fiber,
It is a high-strength, high-elasticity reinforcing fiber such as boron fiber, and its form may be continuous fiber, long fiber, etc., or it may be multifilament or monofilament. The reinforcing fibers can be used in the form of a unidirectional or bidirectional woven fabric, a mat, or the like, in which the reinforcing fibers are arranged in a straight line, in which the arrayed bodies are stacked one on top of the other so that the directions of their fiber axes intersect with each other.

(Example) The present invention will be explained below with reference to Examples, but these do not limit the scope of the present invention.

Here, "parts" in the examples mean "parts by weight."

Example I EPPN201 (manufactured by Nippon Tohokusha) 45 parts, AER33
1 (manufactured by Asahi Kasei Kogyo Co., Ltd.), 25 parts of AER661 (manufactured by Asahi Kasei Kogyo Co., Ltd.), and 5 parts of BF-1000 (manufactured by Adeka Argus Co., Ltd.) were added to Nigu, and after stirring and mixing, dicyandiamide (hereinafter abbreviated as DICY) was added. Part 4, 3-(3,
4-dichlorophenyl)-1,1-N dimethylurea (hereinafter abbreviated as DCMU) was added and mixed with stirring to obtain an epoxy resin composition for prepreg.

The viscosity characteristics of this epoxy resin composition were measured using a rheometer MR.
3 (manufactured by Rheology) at a heating rate of 3°C/min, the viscosity at 70°C was 300 poise,
The bottom viscosity was 10 voids. This viscosity property was appropriate for the prepreg manufacturing process.

Next, commercially available high-strength carbon steel! (Tensile strength: 400 kg/2, elastic modulus: 23.5 t/2) Hi-Carporon (manufactured by Asahi Kasei Carbon Fiber Co., Ltd.) was impregnated with the above resin composition by the true melt method to form a unidirectional carbon fiber blibreg with a resin content of 40%. Obtained.

The surface tackiness of this prepreg was examined by fingertip sensory testing and was found to be moderate, and workability during layup was good.

Next, the resin flow amount was determined to be 15% by the method described in JIS K-7071-1988r "Testing Method for Prepreg Made of Carbon Fiber and Epoxy Resin".

Next, the moldability of this prepreg was tested by molding a badminton racket. For molding, the racquets were first wrapped at a predetermined lamination angle, then set in a mold and cured at 150°C for 30 minutes at an internal pressure of 5 kg/d.When observing the surfaces of the 10 manufactured rackets, there were no wrinkles or wrinkles. It was in good condition with no defects such as voids.

Example 2 EPPN201 (manufactured by Nippon Tohokusha) 45 parts, AER33
1 (manufactured by Asahi Kasei Industries, Ltd.), 25 parts of AER661 (manufactured by Asahi Kasei Industries, Ltd.), 10 parts of BF-1000 (manufactured by Adeka Argus), 4 parts of DICY, and 3 parts of DCMU were mixed in the same manner as in Example 1.

The resulting resin had a viscosity of 500 voids at 70° C. and a bottom viscosity of 12 voids.

Next, it was made into a prepreg in the same manner as in Example 1, and the tackiness was evaluated and found to be appropriate. Furthermore, the measured value of the resin flow amount was 10%, which was further decreased compared to Example 1.

In addition, in a moldability test of badminton rackets, all 10 produced badminton rackets were good with no surface defects.

Comparative Example EPPN201 (manufactured by Nihon Tohokusha) 45 parts, AER33
1 (manufactured by Asahi Kasei Industries, Ltd.), 25 parts of AER661 (manufactured by Asahi Kasei Industries, Ltd.), 4 parts of DICY, and a part of DCMU were mixed in the same manner as in Example 1.

The resulting resin had a viscosity of 250 poise at 70° C. and a bottom viscosity of 7 poise.

Next, it was made into a prepreg in the same manner as in Example 1, and the tackiness was evaluated and found to be appropriate.

On the other hand, the measured value of resin flow amount was 19%, which was higher than in the example. In addition, in a moldability test of badminton rackets, clear wrinkles and voids were observed on the surface of 4 out of 10 produced, and the defective rate was high.

These results are summarized in Table 1.

Table 1 (Effects of the Invention) According to the present invention, it is possible to provide a matrix resin composition for CFRP that has particularly excellent properties in resin flow resistance and moldability, and this will contribute to the development of the industry. There are some extremely significant contributions.

(1 other person)

Claims (1)

[Claims] An epoxy resin composition for prepreg, characterized in that it contains intramolecularly epoxidized polybutadiene.