JPH0316369B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition suitable for molding with a cured epoxy resin using a mold such as transfer molding, injection molding, or compression molding. The curable resin composition of the present invention can provide a semi-cured product with a portable strength by heating for a short time, so the semi-cured product is removed from the mold,
By performing post-curing outside the mold, the efficiency of mold use can be increased. The activation energy of epoxy resins is lower than that of other thermosetting resins, such as phenolic resins and unsaturated polyester resins, and the temperature dependence of the curing rate is also small. Therefore, in order to achieve curing in a short time, methods are used in which a polymerkabutane compound is used as a curing agent or a curing accelerator such as NaSCN or NaI is used in combination with an amine-based cured product. In the case of rapid curing, since the storage stability (pot life) of the composition is short, two parts of the resin solution and curing agent solution are used.
In reality, it is stored as a liquid, and the two liquids are mixed together just before hardening. In this case, the epoxy resin is bisphenol A with an epoxy equivalent of 160 to 230.
Relatively low molecular weight liquid epoxy resins such as diglycidyl ether of bisphenol F, diglycidyl ether of bisphenol F, and novolak epoxy resin are used. In so-called RIM, the two liquids are mixed in a nozzle, injected into the cavity of a mold, and cured in the mold. RIM does not cause clogging of the nozzle due to curing of both liquids, and it is difficult to design the nozzle and mold in order to fill every corner of the cavity of the injection mold with the resin solution.
Currently, the proportion of epoxy resin molding in the epoxy resin molding field is still small. When molding epoxy resins, the resin composition (epoxy resin, curing agent, , type of accelerator) and molding method are selected. Epoxy resins with a long pot life are used as fillers,
It has the advantage of being easy to mix with glass fibers, pigments, curing agents, etc., and is generally a high molecular weight epoxy resin. Since this material is generally solid at room temperature, the molding material must be preheated and plasticized in advance, as is done in compression molding, transfer molding, and injection molding, and then this plasticized material is placed in the mold cavity. It is filled under pressure and then heated (140 to 200°C) under pressure to harden and mold. In these molding methods, it has been proposed to set the heating temperature to 220 to 250°C in order to speed up the hardening time, but heat curing at a temperature higher than the heat distortion temperature of the cured product results in the cured product being demolded. This is undesirable because it causes deformation. The present inventors believe that if a semi-cured product can be obtained with a hardened surface that does not deform even when taken out of the mold, post-curing of this semi-finished product should be done at an appropriate temperature. The process can be carried out in a heating furnace with the semi-finished product removed from the mold, and the mold from which the semi-finished product is taken out can be used immediately to manufacture the next semi-cured product, improving the productivity of products per mold. Focusing on this, we investigated various epoxy resin compositions that can provide such semi-cured products, and found that an epoxy resin composition with a specific blending ratio satisfies these conditions, leading to the present invention. That is, the present invention comprises: (A) component: 100 parts by weight of a brominated bisphenol epoxy resin having an epoxy equivalent of 700 to 5000 and a bromine content of 30 to 52% by weight (B) component: an average molecular weight of 2000 ~5000 bisphenol-based epoxy resin 0~300 parts by weight Component (C): Epoxy resin curing agent Appropriate amount A composition containing the above components (A), (B), and (C), and a glass of this composition. Transition temperature is 50~150℃
The present invention provides an epoxy resin composition characterized by the following. In the present invention, the brominated bisphenol epoxy resin as component (A) has the general formula, for example, [In the formula, A is -CH ₂ -,

[Formula] -S-, -O -, -S-S-,

[expression] or

[Formula], where n is an integer from 2 to 20] A brominated bisphenol epoxy resin or a mixture thereof. This brominated bisphenol epoxy resin is
For example, it is produced by reacting brominated bisphenols or a mixture of brominated bisphenols and bisphenols with epichlorohydrin in the presence of an alkaline catalyst, such as caustic soda (one-step process). In addition, brominated bisphenols or a mixture of brominated bisphenols and bisphenols and epichlorohydrin can be combined with tetramethylammonium bromide, tetraethylammonium chloride, cetyltriethylammonium bromide, ethyltriphenylphosphonimiodine, methyltrioctylphosphonium dimethylphosph It can also be produced (two-step process) by carrying out an addition reaction in the presence of a catalyst such as ate, followed by adding caustic soda to complete the dehydrochlorination reaction. Furthermore, polyphenols obtained by reacting glycidyl ether of bisphenol with brominated bisphenols and then reacting epichlorohydrin with the polyphenols in the presence of sodium hydroxide may also be used. It can also be produced by reacting a brominated bisphenol epoxy resin with bisphenols to obtain a polyphenol, and then reacting the polyphenol with epichlorohydrin in the presence of caustic soda. Bisphenols include bisphenol S, bisphenol A, bisphenol F, etc.
Examples of the brominated bisphenols include brominated products of these bisphenols. It is necessary that the epoxy equivalent of the brominated bisphenol epoxy resin as component (A) is 700 to 5,000. If the epoxy equivalent is less than 700,
Since the resulting semi-cured product is brittle, it is impossible to take it out of the mold in a semi-cured state. On the other hand, if the epoxy equivalent exceeds 5000, the heat resistance of the resulting cured product will be low because the crosslinking density of the epoxy resin is low. The preferred epoxy equivalent weight is 1500-3500. In addition, the bromine content of this component (A) is 30 to 52% by weight.
It is. When the bromine content is less than 30% by weight, the glass transition temperature is low, and the glass transition temperature of the composition is lower than 50℃.
This makes preparation difficult and makes it difficult to take out the semi-cured product. The bromine content of 52% by weight is the upper limit depending on the raw materials and production method, and it is not possible to produce a brominated bisphenol epoxy resin with a higher bromine content. The epoxy resin of component (A) is Epicoat YL903, Epicoat YL906, Epicoat YL906, and Epicoat YL906 from Yuka Ciel Epoxy Co., Ltd.
It is available under the product names YL914 and YL915. In addition, as component (A), the epoxy equivalent is 700 to 1500.
When using brominated bisphenol-based epoxy resin, the resulting cured product is brittle and may crack due to impact.
5000 bisphenol epoxy resin [component (B)]
It is preferable to use 300 parts by weight or less, preferably 20 to 150 parts by weight, per 100 parts by weight of component (A). The epoxy resin of component (B) can be obtained from Yuka Ciel Epoxy Co., Ltd. under the trade names Epicote 1007 and Epicote 1009. If the amount of the epoxy resin (B) exceeds 300 parts by weight, the flame retardant effect and quick curing function of the brominated bisphenol epoxy resin (A) will decrease. Furthermore, the heat resistance of the resulting cured product also decreases. Next, as the curing agent of component (C), for example, an amino compound having at least one hydrogen atom directly bonded to a nitrogen atom, such as diethylenetriamine, triethylenetetramine, methylhexamethylenediamine, isophoronediamine, xylenediamine, metaphenylene Diamines, diaminodiphenylmethane, diaminodiphenyl sulfone, aniline formaldehyde resins; adducts of these amino compounds with other compounds such as epoxy group-containing compounds, acrylonitrile, acrylic esters, e.g. dimers of aliphatic polyamines and unsaturated fatty acids and polyamide amines derived from acids; polycarboxylic acids or their anhydrides, such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, methylendomethylenetetrahydrophthalic anhydride, maleic anhydride, anhydride trimellitic acid, dodecenylsuccinic anhydride, chlorendic anhydride, etc.; polythiols, such as bis-(2-hydrothioethyloxy)methane; secondary to tertiary amines, such as benzyldimethylamine, tris-
(dimethylaminomethyl)phenol, imidazole, pyridine, piperidine, triethanolamine, etc.; polyphenols such as novolac resin, phenol novolac resin; other dicyandiamide, BF ₃ amine salt, amine with the following structure having a spiro ring 3,9-bis(3-aminopropyl)-2,4,
Examples include amines having a spiro ring obtained by reacting 2 moles of 8,10-tetraoxaspiro[5.5]undecane with 1 mole of butyl glycidyl ether. Among these hardening agents, those that are solid at room temperature are (A),
Aromatic amines such as diaminodiphenylmethane, diaminodiphenyl sulfone, and metaphenylenediamine are preferred from the standpoint of mixing with component (B), and from the viewpoint of curability and heat resistance of the resulting cured product. The amount of the curing agent for component (C) should theoretically be determined by chemically equivalent functional groups (>NH, -OH, +COOH) to the epoxy groups in the epoxy resins (A) and (B) to be cured.
It is sufficient to use an amount of the curing agent containing the amount of curing agent, but the optimum required amount is determined experimentally. If you show the specific amount, (A) and
The amount is 2 to 30 parts by weight per 100 parts by weight of component (B). The resin composition consisting of these components (A), (B) and (C) should be prepared so that its glass transition temperature (Tg) is 50 to 150°C. Tg of composition is 50℃
When the semi-cured product taken out from the mold is post-cured outside the mold, it is necessary to set the post-curing temperature to around 50°C, and the post-curing cannot be carried out in a short time. In addition, the pot life of the composition is short,
Difficult to handle. Conversely, when Tg exceeds 150℃, the melting temperature of the composition is often 250℃ or higher, and therefore the mold temperature for molding is also 250℃ or higher.
It will be around ℃. In that case, the thermal stability of the brominated epoxy resin becomes unstable. In addition to these components (A), (B) and (C), curing accelerators, inorganic fillers, pigments, reinforcing fibers, zinc stearate, etc. can be blended. Such curing accelerators include benzyldimethylamine, α-methylbenzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, 2,4,
Tri-2-ethylhexylate of 6-tris(dimethylaminomethyl)phenol, pyridine, piperazine, quinoline, hexamethylenetetramine, N-methylmorpholine, N,N'-dimethylpiperazine, triethanolamine, N-methylpiperazine, Piperidine, morpholine, BF ₃ piperidine, BF ₃ imidazole, BF ₃ 2 methylimidazole, piperidine acetate, imidazole acetate, 2-methylimidazole acetate, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2 -undecylimidazole, 2-hebutadecylimidazole, 2-
Phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 2-methylimidazolium isocyanurate, 1-cyanoethyl-2-ethyl-
4-Methylimidazole, 2-phenylimidazolium isocyanurate, 1-cyanoethyl-
Examples include amine compounds having active hydrogen such as 2-undecyl trimellitate imidazolium. Inorganic fillers include mica, glass flakes, glass powder, silica powder, talc, calcium carbonate, etc. Pigments include titanium oxide, Benkara, carbon black, etc., and reinforcing fibers include borane-treated glass fiber and epoxy silane-treated glass fiber. , aminosilane-treated glass fiber, carbon fiber, aramid fiber, etc. The epoxy resin composition of the present invention is generally used in powder or tablet form. This molding material is used for high frequency preheaters, heaters, etc.
Preferably after preheating to 100-150℃, 50-150℃,
Preferably, the mold is heated to 100 to 150°C, and then the material is plasticized by applying a pressure of 50 to 300 Kg/cm ² to fill every corner of the mold. It is removed from the mold before it is completely cured. It takes 1 to 3 minutes for the semi-cured product to exhibit sufficient strength to not deform when removed from the mold. The taken out semi-cured product is further post-cured at a temperature of 60-180°C for 6-13 hours in an unrestrained state,
It becomes a completely cured product. In the field of epoxy resin casting, 90 to 150
C. for 1 to 4 hours, and then postcured at a temperature higher than the precuring temperature, for example, 150 to 200.degree. C., for 3 to 10 hours to obtain a cured product. In this case, pre-curing and post-curing are performed within the same mold. In contrast to this casting method, when compression molding, transformer molding, or injection molding is performed using the resin composition of the present invention, only pre-curing is performed inside the mold, and post-curing can be performed outside the mold. Productivity per mold can be greatly improved. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 (a) Brominated bisphenol A-based epoxy resin “Epicote YL906” [trade name manufactured by Yuka Ciel Epoxy Co., Ltd., epoxy equivalent 1050, bromine content 50% by weight, Tg 88°C) 100 parts by weight (b) 3mm length chopped strand glass fiber
30 parts by weight (c) Diaminodiphenylmethane 5.1 parts by weight The above components (a) and (b) were kneaded in a kneader at 140°C for 20 minutes, then (c) was added, and after kneading at the same temperature for 2 minutes, It was rapidly cooled to 20℃ and coarsely ground (Tg of the ground material was
67℃). This pulverized material was heated for 120 seconds in the pot of a transfer molding machine (temperature set at 180°C) to plasticize it, then filled into the mold cavity of a transfer mold set at 65°C, and then used with a plunger to produce 80kg/ cm ² for 60 seconds, the mold was opened and the plate-shaped semi-cured product was taken out. This semi-cured product was heated at 60°C for 2 hours and at 80°C for 1.5 hours.
After curing, the temperature was gradually raised to 95° C. for 1 hour and 130° C. for 30 minutes to obtain a cured product measuring 70 mm long, 70 mm wide and 5 mm thick without deformation. The heat distortion temperature of this cured product was 150°C or higher. Example 2 (a) Brominated bisphenol A-based epoxy resin “Epikoat YL914” [Epoxy equivalent: 1465, bromine content 50% by weight, Tg 101°C] 100 parts by weight (b) Bisphenol A-based epoxy resin “Epicoat 1009” ( Epoxy equivalent weight 2850, molecular weight 3750]
50 parts by weight (c) 150 parts by weight of silica powder (d) 5.3 parts by weight of diaminodiphenylsulfone After kneading the above (a), (b) and (c) in a kneader at 140°C for 20 minutes, add (d). The mixture was added and kneaded for 2 minutes at the same temperature, then rapidly cooled to room temperature and pulverized (Tg of the pulverized material was 70°C). This pulverized material is melted using an injection molding machine set at a hopper part of 40°C, a cylinder barrel part of 120°C, and a mold temperature of 60°C, and then injected into the mold cavity.
After 2 minutes, the mold was opened to obtain a semi-cured structural material (weighing 350 g) having many bosses and ribs. This semi-cured structural material was heated to 60℃ for 3 hours and then heated to 80℃ for 3 hours.
time, 3 hours at 95℃, 2 hours at 110℃ and 130℃
The temperature was raised stepwise for 2 hours for post-curing to obtain a cured product with no deformation. The heat distortion temperature of this cured product was 150°C or higher. Example 3 (a) Brominated bisphenol A-based epoxy resin “Epicote YL915” [epoxy equivalent: 2569, bromine content 50% by weight, Tg 114°C] 100 parts by weight (b) 3 mm long chopped strands 30 parts by weight (c) Silica powder 50 〃 (d) Phenol Novolac “PN-80” [Product name manufactured by Yuka Ciel Epoxy Co., Ltd., melting point 80°C]
4.5 parts by weight (e) 2-ethyl-4-methylimidazole
0.5 parts by weight The above (a), (b) and (c) were kneaded in a kneader at 155°C for 20 minutes, then (d) and (e) were added, kneaded for another 2 minutes at the same temperature, and then rapidly cooled. , coarsely ground (Tg of the ground product was 92°C). This pulverized material is heated to a pot temperature of 195℃ and a mold temperature of 85℃.
Transfer molding was performed in 3 minutes using a transfer molding machine set to
A semi-cured product of mm was obtained. This semi-cured product was heated to 90℃ for 3 hours, 110℃ for 3 hours, 130℃ for 3 hours, 150℃ for 2 hours and 170℃.
After curing stepwise for 2 hours, a specimen for bending test without deformation was obtained. The bending strength of this test piece was 1230 Kg/cm ² and the heat distortion temperature was 177°C. Comparative Example 1 (a) Brominated bisphenol A-based epoxy resin “Epicoat YL906” (bromine content 50%) 100 parts by weight (b) Bisphenol A-based epoxy resin “Epicoat 1004” (molecular weight 1600) 100 parts by weight (c ) Silica powder 50 〃 (d) Diaminodiphenylmethane 11 〃 The above (a), (b) and (c) were kneaded in a kneader at 120°C for 20 minutes, and after adding (d), the mixture was kneaded for 20 minutes at the same temperature. Kneaded for minutes, rapidly cooled, and then coarsely ground (ground material
Tg is 42℃). This pulverized material is heated at a pot temperature of 150℃ and a mold temperature of 40℃.
Using a transfer molding machine set at .degree. C., a flat semi-cured material measuring 70 mm in length, 70 mm in width and 5 mm in thickness was obtained in 3 minutes. This semi-cured material is brittle and difficult to demold;
At the above post-curing temperature, even more deformation occurs, so after demolding, firstly at 45℃ for 93 hours, then at 60℃ for 77 hours.
Post-curing was performed by heating at 80°C for 10 hours, at 95°C for 3 hours, at 110°C for 2 hours, and at 130°C for 2 hours to obtain a cured product with a heat distortion temperature of 155°C and no deformation. Comparative Example 2 (a) Brominated bisphenol A-based epoxy resin “Epicote YL903” [Epoxy equivalent: 468, bromine content 50% by weight, Tg 56°C] 100 parts by weight (b) Calcium carbonate 100 (c) Diaminodiphenylsulfone 13.1 〃 Knead the above (a) and (b) in a kneader at 100℃ for 20 minutes,
Further, (c) was added, and after kneading at the same temperature for 2 minutes, the mixture was rapidly cooled to 20°C and pulverized (Tg of the pulverized product was 40°C). This pulverized material is placed in a pot temperature of 150℃ and a mold temperature of 25℃.
When I tried to mold a test piece for a bending test by using a transfer molding machine set to
Even after 30 minutes, it was difficult to take out the semi-cured product without losing its shape. Examples 4 to 14, Comparative Examples 3 to 5 In Example 1, the composition shown in Table 1 was used as the epoxy resin composition, and the conditions for post-curing the semi-cured product were changed as shown in the table. was similarly transfer molded to obtain a cured epoxy resin product. The glass transition point of this cured product is shown in the same table. The epoxy resin used was Epicoat (trade name) manufactured by Yuka Ciel Epoxy Co., Ltd., and its grade number is listed in the table. The molecular weight of the epoxy resin is as follows. Grade name Molecular weight Epicote 1001 (900) 〃 1004 (1600) 〃 1007 (2000) 〃 1009 (3750) 〃 1100 (4000) The abbreviations of the accelerators in the table are as follows. PN-80: Phenol novolak 2E4MZ: 2-ethyl-4-methylimidazole

【table】

【table】

Claims (1)

[Claims] 1 Component (A): 100 parts by weight of a brominated bisphenol epoxy resin having an epoxy equivalent of 700 to 5000 and a bromine content of 30 to 52% by weight Component (B): An average molecular weight of 2000 to 5000 bisphenol epoxy resin 0 to 300 parts by weight Component (C): Epoxy resin curing agent appropriate amount A composition containing the above components (A), (B) and (C). Glass transition temperature is 50~150℃
An epoxy resin composition characterized by: 2. The epoxy resin composition according to claim 1, wherein the epoxy resin curing agent as component (C) is an aromatic amine. 3. The epoxy equivalent of the epoxy resin of component (A) is
700 to 1500, the epoxy resin composition according to claim 1. 4 The amount of component (B) used per 100 parts by weight of component (A),
The epoxy resin composition according to claim 3, characterized in that the amount is 20 to 150 parts by weight.