JP3017812B2 - Aramid fiber reinforced resin molding material and fiber reinforced resin molding made from the molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aramid fiber reinforced resin molding material and an aramid fiber reinforced resin molded product obtained by molding and curing the molding material. More specifically, the present invention relates to an aramid fiber reinforced resin molding material having excellent interfacial adhesion between a resin and an aramid fiber and having excellent moldability and workability, and an aramid fiber reinforced resin molded article having high fatigue resistance.

[0002]

2. Description of the Related Art Aramid fiber or aramid fiber woven fabric is a material excellent in both mechanical and electrical properties, and has been studied for various applications as a reinforcing material for fiber reinforced resin, and has been put to practical use. Particularly, as a matrix resin of a fiber-reinforced resin molding material using aramid fibers as a reinforcing material, epoxy resin is mainly used from the viewpoint of adhesion between the aramid fibers and the matrix resin.

However, since the epoxy resin has a high viscosity, it requires a long time to impregnate the reinforcing material when producing a fiber-reinforced resin molding material by using the epoxy resin, or a solvent when the resin is used as an epoxy resin varnish. Need to be removed. Also, when curing the molding material,
Due to the necessity of heating at a high temperature for a long time, there are restrictions on the molding method or the shape and size of the molded product.

On the other hand, as a matrix resin having excellent moldability and workability, a vinyl ester resin or an unsaturated polyester resin obtained by mixing a radical polymerizable monomer such as styrene with epoxy (meth) acrylate is well known. .

However, when these resins are used as the matrix resin of the aramid fiber reinforced resin molding material, the interfacial adhesion between the matrix resin and the reinforcing material is insufficient.
In fact, only a fiber-reinforced resin molded product having poor long-term reliability as a composite material such as fatigue resistance can be obtained.

[0006]

SUMMARY OF THE INVENTION In view of these circumstances, the present inventors have developed an aramid fiber reinforced resin molding material which is excellent in workability and moldability and excellent in adhesion to an aramid fiber reinforcement. As a result of intensive research, the present invention has been achieved.

That is, an object of the present invention is to provide an aramid fiber reinforced resin molding material excellent in the above-mentioned characteristics and an aramid fiber reinforced resin excellent in long-term reliability as a composite material such as fatigue resistance obtained by molding and curing the molding material. It is to provide a molded article.

[0008]

According to the present invention, there is provided a urethane (meth) acrylate (A) having two or more (meth) acryloyl groups in one molecule, 15 to 50% by weight, and three or more in one molecule. An epoxy group-containing epoxy (meth) acrylate (B) obtained by reacting acrylic acid and / or methacrylic acid with an epoxy resin having an epoxy group at a ratio of 0.3 to 0.8 equivalent of carboxyl group per equivalent of epoxy group. ) 15 to 50% by weight and a radical polymerizable monomer
(C) 20 to 60% by weight (provided that the total of urethane (meth) acrylate (A), epoxy group-containing epoxy (meth) acrylate (B) and radical polymerizable monomer (C) is 10
0% by weight. ), An organic peroxide (D) and an aramid fiber reinforcing material (E).

[0009] The present invention also relates to an aramid fiber reinforced resin molded product obtained by molding and curing the above molding material.

[0010]

The aramid fiber reinforced resin molding material of the present invention has a low viscosity of the matrix resin, so that the aramid fiber has good impregnating properties, and does not require the removal of a solvent during curing over a wide temperature range from room temperature to high temperature. It can be molded in a short time. Therefore, the restriction on the size and shape of the fiber-reinforced resin molded product or the molding method can be remarkably relaxed, and it can be applied to the molding of a large-sized molded product or a complex-shaped molded product or the continuous molding method with high productivity. .

The fiber-reinforced resin molded product obtained from the aramid fiber-reinforced resin molding material of the present invention is obtained by using a resin such as a conventional unsaturated polyester resin or vinyl ester resin as a matrix resin of the aramid fiber-reinforced resin molded product. Unlike the case where it is used, since the interfacial adhesion between the matrix resin and the reinforcing material is good, it has excellent mechanical strength and also has excellent long-term fatigue resistance.

Urethane (meth) acrylate (A) having two or more (meth) acryloyl groups in one molecule used in the present invention (hereinafter, urethane (meth) acrylate
(A). ) Is obtained by the reaction of a polyisocyanate with a hydroxyalkyl (meth) acrylate, or by the reaction of a polyisocyanate with a polyol and a hydroxyalkyl (meth) acrylate. The relative proportions of hydroxyalkyl (meth) acrylate and polyisocyanate or hydroxyalkyl (meth) acrylate, polyol and polyisocyanate used in the reaction are determined by the amount of hydroxyl group in hydroxyalkyl (meth) acrylate or the proportion of hydroxyalkyl (meth) acrylate and polyol. It is preferable that the amount of isocyanate groups in the polyisocyanate is substantially equivalent to the total amount of hydroxyl groups.

The reaction may be carried out in accordance with a conventionally known method for synthesizing urethane (meth) acrylate. For example, in the production of polyurethane such as tertiary amine, tin compound such as di-n-butyltin dilaurate or tin octylate. The reaction may be carried out at a temperature in the range of room temperature to 120 ° C. in the presence of a known urethanization catalyst or a polymerization inhibitor such as hydroquinone, benzoquinone, t-butylcatechol, or molecular oxygen.

In the above method, an inert solvent such as toluene, xylene, methyl ethyl ketone or ethyl acetate is preferably added to the reaction system, preferably a radical polymerizable monomer described below.
(C) can coexist.

In reacting a hydroxyalkyl (meth) acrylate with a polyol and a polyisocyanate, first, a hydroxyalkyl (meth) acrylate is reacted with a polyisocyanate, and then the remaining isocyanate group is reacted with the polyol. And a polyisocyanate and then reacting a terminal isocyanate group with hydroxyalkyl (meth) acrylate, and a method of simultaneously reacting hydroxyalkyl (meth) acrylate, polyol and polyisocyanate. However, the present invention does not depend on these reaction methods.

The hydroxyalkyl (meth) acrylate is not particularly limited, but includes 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,
Hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate and the like are readily available industrially and are preferred examples.

The polyisocyanate is bifunctional or trifunctional.
Polyfunctional or higher functional, containing at least two isocyanate groups selected from aliphatic, alicyclic and aromatic isocyanate groups in the same polyisocyanate compound or aliphatic or alicyclic or aromatic isocyanate compound May be. Examples of such polyisocyanates include ethylene diisocyanate, tetraethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, tolylene diisocyanate, meta-xylene diisocyanate, and 4,4'- isocyanate. Examples thereof include diphenylmethane diisocyanate and polymethylene polyphenylisocyanate, and these can be used alone or in combination of two or more.

The polyol is a polyfunctional or bifunctional or trifunctional or higher functional polyol. As the bifunctional polyol, for example, ethylene glycol, propylene glycol,
1,6-hexanediol, 1,4-cyclohexanediol, 1,4-bis (2'-hydroxyethoxy) benzene, 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4 8,10-tetraoxaspiro [5,5] undecane, bis (4-hydroxyethoxy-phenyl) sulfone, 3 (4), 8 (9) - dihydroxymethyl tricyclo [5,2,1,0 ^{2, 6]} Decane,
Glycols such as 4,4'-bis (2'-hydroxypropyl) bisphenol A, 4,4'-bis (2-hydroxyethyl) tetrabromobisphenol A, polyethylene glycol and polypropylene glycol, polyether polyols, or poly Polyester polyols such as (ethylene adipate), poly (ethylene sebacate), poly (propylene sebecate), and poly (propylene pimerate). Examples of trifunctional or more polyfunctional ones include glycerol, Pentaerythritol, trimethylolpropane and the like can be mentioned, and these can be used alone or in combination of two or more.

The epoxy group-containing epoxy (meth) acrylate (B) used in the present invention has three or more epoxy groups in one molecule, and preferably has an epoxy equivalent of 100 to 6.
Acrylic acid and / or methacrylic acid are added to the epoxy resin of No. 00 at a carboxyl group ratio of 0.3 per equivalent of epoxy group.
~ 0.8 equivalents are obtained by reacting,
A compound having a (meth) acryloyl group and an epoxy group in one molecule.

If the carboxyl group equivalent to be reacted is less than 0.3, a sufficient crosslinking density cannot be obtained due to curing of the obtained molding material, and the mechanical strength of the aramid fiber reinforced resin molded product decreases. On the other hand, if it exceeds 0.8 equivalents, the interfacial adhesion between the aramid fiber reinforced material and the matrix resin in the obtained molding material becomes poor, and the fatigue resistance of the resin molded product is undesirably reduced.

Therefore, when synthesizing the epoxy group-containing epoxy (meth) acrylate (B), the proportion of acrylic acid and / or methacrylic acid to be reacted with the epoxy resin is adjusted according to the number of epoxy groups in one molecule of the epoxy resin. It is necessary to adjust in the range of 0.3 equivalent to 0.8 equivalent.

Examples of the epoxy resin include novolak type epoxy resins such as phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, and brominated phenol novolak type epoxy resin; tetraphenyl glycidyl ether ethane; Polyfunctional glycidyl ether type epoxy resin such as phenyl glycidyl ether methane; triglycidyl-P-aminophenol, triglycidyl isocyanurate, tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-1,3-bisaminomethylcyclohexane Such as multifunctional glycidylamine type epoxy resins having three or more epoxy groups in one molecule It may be used by mixing above.

The reaction may be carried out in accordance with a conventionally known method for synthesizing an epoxy (meth) acrylate, for example, a known esterification catalyst such as lithium chloride and lithium bromide, hydroquinone, benzoquinone, t-butylcatechol, and the like. 60-1 in the presence of a polymerization inhibitor such as molecular oxygen
What is necessary is just to heat to the temperature range of 50 degreeC, and to perform it. In the above method, an inert solvent such as toluene, xylene, methyl ethyl ketone, or ethyl acetate, preferably a radically polymerizable monomer (C) described below, can be coexisted in the reaction system.

The radical polymerizable monomer used in the present invention
(C) is not particularly limited as long as it is a compound having at least one radically polymerizable unsaturated group in one molecule and having a molecular weight of about 400 or less, for example, styrene, vinyltoluene, p-methylstyrene, halogenated Styrene, divinylbenzene, methacrylic acid, acrylic acid, diallyl phthalate, triallyl cyanurate, vinyl acetate or methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl acrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, Such as trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, trimethylolpropane diacrylate, tris (2-acryloyloxyethyl) triazine, etc. Esters of acrylic acid and / or methacrylic acid can be mentioned, and one or more of these can be used.

A resin composition comprising a urethane (meth) acrylate (A), an epoxy group-containing epoxy (meth) acrylate (B) and a radical polymerizable monomer (C) is used as a matrix resin of the molding material of the present invention. Can be The proportion of each component used in this resin composition is urethane (meth)
The acrylate (A) is 15 to 50% by weight, the epoxy group-containing epoxy (meth) acrylate (B) is 15 to 50% by weight, and the radically polymerizable monomer (C) is 20 to 60% by weight.

If at least one of urethane (meth) acrylate (A) and epoxy group-containing epoxy (meth) acrylate (B) is less than 15% by weight, interfacial adhesion between the resin composition and the aramid fiber reinforcing material Aramid fiber reinforced resin molded products having excellent fatigue resistance cannot be obtained. In addition, when the content of either one of the components (A) and (B) exceeds 50% by weight, the viscosity increases, the workability decreases, and the impregnating property to the aramid fiber decreases. Aramid fiber reinforced resin molded products with excellent strength cannot be obtained.

If the proportion of the radical polymerizable monomer (C) is less than 20% by weight, the viscosity increases, the workability decreases, and the curability deteriorates. On the other hand, if this ratio is set to a large amount exceeding 60% by weight, an aramid fiber reinforced resin molded article excellent in fatigue resistance cannot be obtained. As the organic peroxide (D), those commonly used as curing agents for radically polymerizable thermosetting resins such as unsaturated polyester resins can be used without particular limitation. Examples of such an organic peroxide (D) include, for example, benzoyl peroxide, dicumyl peroxide, t-butylperoxybenzoate, and t-butylperoxybenzoate.
Butylperoxy-2-ethylhexanoate, cyclohexanone peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 2,5-dimethyl -2,5-di-t-butylperoxyhexine-3 and the like, and if necessary, an organic acid salt such as cobalt and manganese, and a redox accelerator such as dimethylaniline and dimethyl-p-toluidine are used in combination. You can also.

The amounts of the organic peroxides (D) used are urethane (meth) acrylate (A), epoxy group-containing epoxy (meth) acrylate (B) and radical polymerizable monomer.
(C) 0.3 to 100 parts by weight of the resin composition comprising
A range of 5 parts by weight is preferred.

The aramid fiber reinforced material (E) used in the present invention is aramid (aromatic polyamide) in various forms such as short fibers, long fibers, nonwoven fabrics and woven fabrics. Usual ones can be used. The aramid referred to in the present invention is represented by the general formula -NH-Ar ₁
-NH-CO-Ar ₂ -CO- and / or -NH
-Ar ₃ -CO- repeating unit (wherein, Ar ₁ , Ar ₂ ,
Ar ₃ independently represents a divalent aromatic cyclic group), and among them, polyparaphenylene terephthalamide, polymetaphenylene isophthalamide, polyparabenzamide and the like are heat-resistant and highly elastic. Particularly preferred from the viewpoint of strength.

The amount of the aramid fiber reinforcing material (E) is preferably in the range of 5 to 80% by weight in the molding material of the present invention. If the amount is less than 5% by weight, the reinforcing effect of the reinforcing material becomes insufficient, and if the amount exceeds 80% by weight, it becomes difficult to uniformly impregnate the resin composition into the reinforcing material. In order to obtain the aramid fiber reinforced resin molding material of the present invention, for example, a mixture of the resin composition described above and a predetermined amount of an organic peroxide (D) as a curing agent is impregnated into an aramid fiber reinforced material (E). As the impregnation method, conventionally known methods such as dipping and coating with a roll can be freely adopted. The resin composition may be freely blended with various conventionally known additives such as a thickener and a mold release improver, in addition to the pigment and the filler. Further, other resin components such as unsaturated polyester and epoxy (meth) acrylate may be partially mixed and used as long as the effects of the present invention are not impaired.

The molding and curing of the aramid fiber reinforced resin molding material of the present invention to obtain a fiber reinforced resin molded product may be performed according to a conventionally known molding method. For example, in the case of a sheet-like molding material obtained by impregnating a resin composition and an organic peroxide into a sheet-like aramid fiber reinforced material such as a nonwoven fabric or a woven fabric, one or more sheet-like molding materials are laminated. When heated under pressure, a plate-like molded product is obtained. In the case of a bulk molding material obtained by mixing and impregnating a short fibrous reinforcing material with a resin composition and an organic peroxide, it is possible to efficiently produce molded articles of various shapes by an injection molding machine or a press molding machine. it can.

[0032]

EXAMPLES The present invention will be described below in detail with reference to examples, but the scope of the present invention is not limited by these examples. In the examples, “parts” and “%” mean “parts by weight” and “% by weight” in principle.

[0033]

REFERENCE EXAMPLE 1 In a four-necked flask, 144 parts of hydroxypropyl methacrylate, diphenylmethane diisocyanate containing polyisocyanate (Sumitomo Bayer Urethane Co., Ltd., Sumidur 44V20, isocyanate content 3)
(0.7%) 137 parts, 151 parts of styrene, 0.8 parts of dibutyltin dilaurate and 0.2 parts of benzoquinone are charged, and reacted at 40 ° C. for 3 hours and further at 80 ° C. for 2 hours in an air stream, and infrared absorption is performed. After confirming the disappearance of the isocyanate group in the spectrum, a 35% mixture of urethane methacrylate (1) and styrene was obtained.

[0034]

Reference Example 2 In a four-necked flask, hydroxyethyl acrylate (58 parts), tolylene diisocyanate (87 parts), 2,2
89 parts of polyol obtained by condensation reaction of 2-bis (p-hydroxyphenyl) propane and propylene oxide at a molar ratio of 1: 2.1, 191 parts of styrene, 0.85 parts of dibutyltin dilaurate and 0.1 part of benzoquinone. 2
Add 1 part and add 10 hours at 40 ° C for 3 hours under air flow.
The mixture was reacted at 0 ° C. for 2 hours, and it was confirmed that the isocyanate group had disappeared by an infrared absorption spectrum. Thus, a 45% mixture of urethane acrylate (2) and styrene was obtained.

[0035]

Reference Example 3 A phenol novolak type epoxy resin (DEN438, manufactured by Dow Chemical Co., Ltd., epoxy equivalent: 178, average epoxy group in one molecule: 3.6) in a four-necked flask.
178 parts, methacrylic acid 65 parts, lithium chloride 0.80
Parts and benzoquinone 0.15 part, and reacted at 110 ° C. for 2.5 hours under an air stream to obtain an epoxy group-containing epoxy methacrylate (1) having an acid value of 1.5, and further blending 162 parts of styrene, A mixture of 40% styrene was obtained.

[0036]

REFERENCE EXAMPLE 4 A cresol novolak type epoxy resin (manufactured by Ciba Geigy, ECN1280, epoxy equivalent 227, average epoxy group 5.1 in one molecule) was placed in a four-necked flask.
227 parts, acrylic acid 32 parts, styrene 50 parts, chromium naphthenate (chromium content 3%) 1.5 parts and benzoquinone 0.19 parts are charged, and 115 ° C. in an air stream.
For 2 hours to obtain a styrene mixture of an epoxy group-containing epoxy acrylate (2) having an acid value of 1.0, and 162 parts of styrene were further blended to obtain a 45% styrene mixture.

[0037]

Reference Example 5 Tetraglycidyl diaminodiphenylmethane (YT434, manufactured by Toto Kasei Co., Ltd., epoxy equivalent 123, average epoxy group 4 in one molecule) 12 in a four-necked flask
3 parts, methacrylic acid 43 parts, p-methylstyrene 50
Part, lithium chloride 0.55 part and benzoquinone 0.1
Charge 4 parts and heat at 110 ° C. for 2 hours to obtain an acid value of 2.5
And a p-methylstyrene mixture of epoxy group-containing epoxy methacrylate (3)
One part was blended to give a mixture of 40% p-methylstyrene.

[0038]

Examples 1 to 5 and Comparative Examples 1 to 3 Urethane (meth) acrylates (1) and (2) containing the radical polymerizable monomers obtained in Reference Examples 1 and 2 were obtained in Reference Examples 3 to 5. Using epoxy group-containing epoxy (meth) acrylates (1), (2) and (3) containing the obtained radical polymerizable monomer, Table 1
Was obtained.

100 parts of each of these resin compositions contains 2,
A liquid obtained by blending 1 part of 5-dimethyl-2,5-di-t-butylperoxyhexyne-3 was 300 mm × 300 mm.
Aramid fiber satin cloth K-285 cut into mm
KE420 (manufactured by DuPont) was impregnated to obtain the aramid fiber reinforced resin molding materials (1) to (5) and the comparative molding materials (1) to (3) of the present invention. The amount of the aramid fiber reinforced material in each molding material was 40%.

Next, the obtained molding material was laminated on 12 plies in the same fiber direction, and spacers made of silicone rubber were applied to all sides, and 150 mm under a pressure of 10 kg / cm ^2.
Press molding was performed at 1 ° C. for 1 minute, and post-curing was further performed at 150 ° C. for 30 minutes to obtain an aramid fiber reinforced resin laminate having a thickness of 2.5 mm.

A test piece having a size of 140 mm × 40 mm was cut out from the obtained laminate with the fiber orientation direction as each length and width, and an electro-hydraulic servo valve type bending fatigue tester manufactured by Tokyo Testing Machine Co., Ltd. was used. The fatigue resistance properties of the aramid fiber reinforced resin laminate were evaluated. The evaluation results are summarized in Table 1.

The evaluation of the fatigue resistance was carried out using the span 115
A stress of 30 kg / mm ² at mm and 5 Hz was applied to the center of the span, and the number of cycles was increased by 20% based on the initial amplitude.

[0043]

[Table 1]

[0044]

The aramid fiber reinforced resin molding material of the present invention has good impregnating properties for aramid fibers due to the low viscosity of the matrix resin, and can be cured in a short time without the need for solvent removal during curing. Excellent workability and moldability.

Therefore, according to the molding material of the present invention,
It is easy to manufacture large aramid fiber reinforced resin molded products and highly productive resin molded products by the continuous method, and to obtain long-term reliable aramid fiber reinforced resin molded products with excellent fatigue resistance. it can.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-31413 (JP, A) JP-A-4-171787 (JP, A) JP-A-4-171788 (JP, A) JP-A-3-3-1 243631 (JP, A) JP-A-2-261821 (JP, A) JP-A-3-215529 (JP, A) JP-A-63-265931 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) C08J 5/24 C08J 5/04-5/10 C08F 290 / 06,290 / 14

Claims (2)

(57) [Claims] 1. A urethane (meth) acrylate (A) having two or more (meth) acryloyl groups in one molecule.
Acrylic acid and / or methacrylic acid are added to an epoxy resin having three or more epoxy groups in one molecule by a carboxyl group ratio of 0.3 to
15 to 50% by weight of an epoxy group-containing epoxy (meth) acrylate (B) and 20 to 60% by weight of a radical polymerizable monomer (C) obtained by reacting at a ratio of 0.8 equivalent (urethane (meth) acrylate (A), the total of the epoxy group-containing epoxy (meth) acrylate (B) and the radically polymerizable monomer (C) is 100% by weight.) An aramid fiber reinforced resin molding material containing an aramid fiber reinforced material (E). 2. An aramid fiber reinforced resin molded product obtained by molding and curing the molding material according to claim 1.