WO2003014181A1 - Curing accelerator for amine hardener for epoxy resin and method of accelerating epoxy resin curing - Google Patents

Abstract

A curing accelerator for an amine hardener for epoxy resins, characterized by containing as an active ingredient a thiocyanic acid salt of a compound represented by the formula (1); and a method of curing acceleration with the curing accelerator. (R1)(R2)NNH2 (1) [In the formula, R1 and R2 are the same or different and each represents C1-8 alkyl, phenyl, or pyridyl, or R1 and R2 are bonded to each other to form either C2-11 alkylene or a group represented by -R3-R4-R5- (R3 and R5 are the same or different and each represents C1-8 alkylene and R4 represents oxygen, sulfur, a group represented by =NR6 or =NNH2, provided that R6 represents C1-8 alkyl).]

Description

 TECHNICAL FIELD The present invention relates to a curing accelerator for an amine-based epoxy resin curing agent and a method for promoting curing of an epoxy resin.

 The present invention relates to a curing accelerator for an amine epoxy resin curing agent and a method for promoting curing of an epoxy resin. Light

 Rice field

 Landscape technology

 Epoxy resins have excellent electrical insulation, moisture resistance, heat resistance, solder resistance, chemical resistance, durability, adhesion, mechanical strength, etc. It is widely used as a sealing material, paint, adhesive, etc. in various fields such as construction.

 Conventionally, epoxy resin is cured by adding a curing agent to the epoxy resin and heating. Typical curing agents include, for example, diethylenetriamine, triethylenetetramine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, polyamides, dicyandiamide, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride Acids, methylnadic anhydride, nopolak phenolic resin, tertiary amines, imidazoles, and amine complexes of boron trifluoride.

Among these curing agents, those which cure epoxy resins at room temperature include amine curing agents such as ethylenetriamine, triethylenetetramine, polyamides and tertiary amines. These amine-based curing agents are relatively inexpensive and highly versatile curing agents for epoxy resins, but diethylenetriamine and triethylenetetramine require 4 days for curing, and polyamides and tertiary amines require 7 days. It is.

 By the way, epoxy resin adhesives for outdoor construction are widely used in the field of civil engineering and construction, but as described above, it is very difficult to cure epoxy resin without heating with a conventional curing agent. However, it can take a very long time of 4-7 days to cure. In particular, in winter construction where the outdoor temperature often drops to 10 ° C or less, it is essential to start the curing reaction by heating.

 An object of the present invention is to provide a curing accelerator capable of remarkably improving the curing speed of these amine-based epoxy resin curing agents, and a method of accelerating the curing. Disclosure of the invention

 The present invention relates to a curing accelerator for an amine-based epoxy resin curing agent comprising a thiocyanate of a compound represented by the formula (1) as an active ingredient, and a curing acceleration method using the curing accelerator. Related.

(R ¹ ) (R ² ) NNH ₂ (1)

(Wherein R ¹ R ² are the same or different and are an alkyl group having 1 to 8 carbon atoms, a phenyl group, a pyridyl group, an alkylene group having 2 to 11 carbon atoms in which both are bonded, or one R ³ — R ⁴ I represents a group represented by R ⁵ — R ³ and R ⁵ are the same or different and are alkylene groups having 1 to 8 carbon atoms, R ⁴ is an oxygen atom, a sulfur atom, a group = NR ⁶ or a group = NNH ₂ R ⁶ represents an alkyl group having 1 to 8 carbon atoms.)

Examples of the alkyl having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isoptyl, t-butyl, s-butyl, n-pentyl, isopentyl, t-pentyl, neopentyl, and n-pentyl. Hexyl, isohexyl, heptyl, octyl and the like can be mentioned. Examples of the alkylene having 2 to 11 carbon atoms include ethylene, propylene, butylene, hexylene, octylene, Tylene, pendecamethylene and the like can be mentioned. Examples of the alkylene having 1 to 8 carbon atoms include methylene, ethylene, propylene, butylene, hexylene, and octylene.

 The thiocyanate of the compound represented by the formula (1) used as an active ingredient of the fat curing accelerator of the amine-based epoxy resin curing agent of the present invention is represented by, for example, an aqueous solution of ammonium thiocyanate represented by the formula (1) Compound is added in an approximately equimolar amount, and the reaction is carried out for about 30 minutes to 5 hours while gradually heating to about 80 ° C while distilling off the produced ammonia and water. . It is preferably used in powder form.

 Specific examples of the compound represented by the formula (1) include 1-aminopyrrolidine (1 AP), 1-aminopiperidine, 1-aminohomopiridine (AHP), 1-aminopiperazine, and 1-amino- N'-methylbiperazine (AMPI), N-aminomorpholine (AMP), N-aminothiomorpholine, 1,1-dimethylhydrazine (UD MH), 1,1-getylhydrazine, 1,1-dipropylhydrazine , 1,1-dibutylhydrazine, monomethylhydrazine, monoethylhydrazine, monopropylhydrazine, monoisopropylhydrazine, monobutylhydrazine, mono tert-butylhydrazine, 1-ethyl-11-methylhydrazine, 1-methylethyl-11 Propylhydrazine, 1-butyl-1-methylhydrazine, 1-methyl1-1-phenylhydrazine, 1,1-diphenylhydrazine Razine, monophenylhydrazine, 2-hydrazinopyridine and the like can be mentioned.

The thiocyanate of the compound represented by the formula (1) can harden an epoxy resin by being used in combination with an amine-based curing agent as described in WO01 / 291109. Yes, but it cannot cure epoxy resin alone. However, this time, it was found that it has an effect of remarkably improving the curing speed of the amine-based epoxy resin curing agent, and it is confirmed that it is useful as a curing accelerator for the amine-based curing agent. Was called.

 Here, the amine-based curing agent includes diethylenetriamine, triethylenetetramine, isophoronediamine, metaxylylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, polyamides, dicyandiamide, hexahydrophthalic anhydride, methyl Examples thereof include tetrahydrophthalic anhydride, methylnadic anhydride, nopolak phenolic resin, tertiary amines, imidazoles, amine complexes of boron trifluoride, and modified products thereof.

 The mixing ratio of the amine-based curing agent to the epoxy resin is not particularly limited. The type of the epoxy resin, the type and the amount of the other additives, the use of the obtained epoxy resin cured product, and the curing conditions (designed curing) It may be appropriately selected from a wide range according to various conditions such as time, curing temperature, curing place, etc., but usually 0.1 to 1 equivalent, preferably 0.6 to 1 equivalent to 1 equivalent of epoxy resin. It is preferable to use it to the extent.

 In the method for accelerating the curing of an epoxy resin according to the present invention, the thiocyanate of the compound represented by the formula (1) is used as a curing accelerator in an amount of 1 to 150 parts by weight based on 100 parts by weight of the amine-based curing agent. Parts, preferably 5 to 50 parts by weight, the curing rate can be improved without substantially changing the physical properties of the cured product. Further, it is preferable to use 0.5 to 1 mol of the thiocyanate of the compound represented by the formula (1) with respect to 10 mol of the amine-based curing agent.

The epoxy resin to which the curing agent for epoxy resin of the present invention can be applied is not particularly limited, and may be a conventionally known epoxy resin. Examples thereof include glycidyl ether type epoxy resins, glycidylamine type epoxy resins, cycloaliphatic epoxy resins, glycidyl ester resins, heterocyclic epoxy resins, and urethane-modified epoxy resins. Glycidyl ether type epoxy resins include bisphenol A type, bisphenol F type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol S type, bisphenol AF type, biphenyl type, naphthalene type, Examples thereof include a fluorene type, a phenol nopolak type, a cresol nopolak type, a DPP nopolak type, a trifunctional type, a tris-hydroxyphenylmethane type, and a tetraphenylolethane type. Examples of glycidylamine type epoxy resins include tetraglycidyldiaminodiphenylmethane, triglycidylisocyanurate, hydantoin type, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, aminophenol type, Examples include ananiline type and toluidine type.

 If necessary, the epoxy resin to which the epoxy resin curing accelerator of the present invention is applied may contain an inorganic filler, a reinforcing material, and the like, which are conventionally added to the epoxy resin. Known inorganic fillers can be used, for example, silica, fused quartz, calcium carbonate, barium carbonate, barium sulfate, hydrated alumina, alumina, hydrated magnesia, zircon, cordierite, silicon nitride, boron nitride, nitrided Aluminum and the like. Known reinforcing materials can be used.Examples include inorganic materials such as glass chops, asbestos, talc, and my strength, glass fibers, potassium titanate fibers, titanium dioxide fibers, wollastonite, zonotolite, and zinc silicate fibers. And organic fibers. It is known that the thermal conductivity, crack resistance, electrical properties, tracking resistance, and the like of the obtained cured product can be adjusted by appropriately changing the type, purity, and amount of the filler and the reinforcing material. Usually, the filler and the reinforcing material are added in a total amount of about 20 to 160 parts by weight, preferably about 50 to 120 parts by weight, based on 100 parts by weight of the epoxy resin. Good to do. The filler and the reinforcing material may be used alone or in combination of two or more.

Further, the epoxy resin to which the curing agent for epoxy resin of the present invention is applied may contain, if necessary, additives conventionally used as additives for epoxy resins. Such additives include, for example, inorganic pigments (particulate titanium dioxide, power—pump racks, red iron oxide, yellow iron oxide, etc.), organic pigments, viscosity modifiers, leveling agents, defoamers, cups Examples include a ring agent, a plasticizer, a diluent, a flame retardant, and an organic solvent. Epoxy resins cured using the epoxy resin curing accelerator of the present invention include, for example, various shapes composed of at least one of various materials such as metals, synthetic resins, cement, ceramics, fibers, and paper. Applicable to articles. Specifically, articles of various shapes are immersed in an epoxy resin to which an amine curing agent and the epoxy resin curing accelerator of the present invention are added, or an amine curing agent and the epoxy resin curing of the present invention are applied to the surface of the article. After applying or coating the epoxy resin to which the accelerator has been added, the resin may be left as it is and cured. In the case of heating, the conditions such as the temperature and the like are determined by the type of epoxy resin, the type and amount of the epoxy resin curing accelerator of the present invention, and the type and amount of epoxy resin to be obtained when other additives are added. It may be appropriately selected according to various conditions such as the use of the cured product, but it is usually about 40 to 80 ° C.

 Further, an epoxy resin to which an amine-based curing agent and the epoxy resin curing accelerator of the present invention are added is formed into a molded article having an arbitrary shape in accordance with a usual molding method such as casting, and this is formed with at least one of various materials. It can be attached to the various shaped articles according to the usual method such as bonding and fitting. The curing conditions at the time of molding may be the same as in the case of application or impregnation.

 ADVANTAGE OF THE INVENTION According to this invention, the outstanding effect that the hardening speed of an epoxy resin can be remarkably improved using a general-purpose amine type hardener is acquired. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

 The commercially available amine epoxy resin curing agents used in the examples and comparative examples are as follows.

Jeffamine D—230 (Huntsman * Corporation, polyoxypropylene diamine), Diephamin D—400 (Huntsman Corporation) Jeffamine D-2000 (manufactured by Huntman's Corporation, polyoxypropylenediamine), Jeffamine T-403 (manufactured by Huntsman Corporation, polyoxypropylenediamine) ,

 Adeiki Hardener EH220 (made by Asahi Denka Kogyo Co., denatured aliphatic polyamine), Adeki Hardener EH227 (made by Asahi Denka Kogyo Co., Ltd., denatured aliphatic polyamine), Epomate RX3 (Japan Epoxy Resin Co., Ltd., heterocyclic ring) Epomate RX32 (Japan Epoxy Resin Co., Ltd., heterocyclic diamine modification), Epomate B 002 (Japan Epoxy Resin Co., Ltd., heterocyclic diamine modification), Epomate RX221 (Japan Epoxy) Resin Corporation, modified aliphatic polyamine), Epicure-1 3560 (Japan Epoxy Resin Co., modified aliphatic polyamine),

 Versamide 125 (manufactured by Henkel Japan K.K., polyamidoamine), Rikiichi Dlight NC 540 Card Light Co., Ltd., manufactured by Fenarcamine, Rikiichi Drain NC 541 LV (Rikiichi Drite. Manufactured by Corporation, Fenarcamine) )

Production Example 1 (Production of 1-aminopyrrolidine thiocyanate)

 76 g (1 mol) of ammonium thiocyanate was placed in a four-necked flask and dissolved in 50 g of water. To this was added 143 g (1 mol) of a 60% aqueous solution of 1-aminopyrrolidine, the pressure was reduced to 20 mmHg at room temperature, and the reaction was carried out while gradually heating, and water and ammonia were distilled off. After keeping at 80 ° C for 2 hours, the mixture was cooled to obtain 142 g of crystals.

 As a result of analysis by NMR, IR, and HP LC, it was confirmed that the product was 1-aminopyrrolidine thiocyanate (yield: 98%).

Example 1 Bisphenol A type epoxy resin [trade name: Epikote 828, epoxy equivalent: 190, manufactured by Japan Epoxy Resin Co., Ltd.] 1 Og, amine-based epoxy resin curing agent and 1-a in the proportions shown in Tables 1-4 Minopyrrolidine thiocyanate (NR-S) is added and mixed, coated on a glass substrate to a thickness of 0.3 mm and cured at room temperature, and the time to dry to the touch or the time until the Shore D hardness reaches 50. Was measured. The results are shown in Tables 1-4. The PHR in the table indicates the mixing ratio (parts by weight) with respect to 100 parts by weight of the epoxy resin. In Table 4, when EDA, DETA, and AEP were used, the time to dry the touch was not measured due to amine brushing, so the time at Shore D50 is shown.

 From the results of Tables 1 to 4, it is understood that the curing rate of the amine-based epoxy curing agent can be significantly improved by using the epoxy resin curing accelerator of the present invention in combination. 【table 1】

PH touch dry

 Curing agent name

 Curing agent NR-S (h)

 Diephamin D— 230 30 9

 Diphamin D— 230 30 10 5.5

 Jeffamine: D— 230 20 10 5.5

 Jeffamine D— 400 55 29

 Jeffamine D— 400 5510 18

 Jiko Farmin D— 400 45 10 18

 Diephamin T— 403 45 10

 Jeffamine T-1 403 45 10 5

Diephamin T— 403 35 10 5 [Table 2]

[Table 3]

PHR Touch drying Hardener name

Hardener NR-S (min) Card light NC 540 35 260 Force light NC 540 35 10 210 Force light NC 540 25 10 180 Force light NC 541 LV 72.5 360 Card light NC 541 72.5 10 135 Card light NC 541 LV 62.5 10 130 [Table 4]

実施例 2

Example 2

 Bisphenol A type epoxy resin [Product name: Epoxy 806, epoxy equivalent: 165, manufactured by Japan Epoxy Resin Co., Ltd.] Amines epoxy resin cured to 10 g at the ratio shown in Table 5 The agent and 1-aminopyrrolidine thiocyanate were added and mixed, applied to a glass substrate at a thickness of 0.3 mm, cured at 5 ° C., and the touch dry time was measured. Table 5 shows the results.

From the results in Table 5, it can be seen that the use of the epoxy resin curing accelerator of the present invention can significantly improve the curing rate of the amine epoxy curing agent even at low temperatures. [Table 5]

Example 3

 Touch dry time was measured in the same manner as in Example 1 except that dimethylhydrazine thiocyanate (UDMH-S) was used instead of 1-aminopyrrolidine thiocyanate. Table 6 shows the results.

 [Table 6]

PHR dry to the touch

 Curing agent name

 Curing agent UDMH-S (min)

 Adekah donor EH220-45 110

 Adekaha Dona EH220 45 10 75

Adekah donor EH220 35 10 85 Industrial applicability

 The thiocyanate of the compound represented by the formula (1) cannot cure an epoxy resin by itself, but has a function of significantly improving the curing speed of an amine epoxy resin curing agent. Very useful as a curing accelerator for

Claims

The scope of the claims 1. A curing accelerator for an amine-based epoxy resin curing agent, comprising a thiocyanate of a compound represented by the formula (1) as an active ingredient. (R ¹ ) (R ² ) NNH ₂ (1) (Wherein, R ¹ R ² are the same or different and are an alkyl group having 1 to 8 carbon atoms, a phenyl group, a pyridyl group, an alkylene group having 2 to 11 carbon atoms by combining both, or one R ³ — R ⁴ I represents a group represented by R ⁵ — R ³ and R ⁵ are the same or different and are alkylene groups having 1 to 8 carbon atoms, R ⁴ is an oxygen atom, a sulfur atom, a group = NR ⁶ or a group = NNH ₂ R ⁶ represents an alkyl group having 1 to 8 carbon atoms.)  2. The curing accelerator according to claim 1, which is in a powder state.  3. When curing an epoxy resin with an amine curing agent, 1 to 150 parts by weight of a thiocyanate of a compound represented by the formula (1) is added as a curing accelerator to 100 parts by weight of an amine curing agent. A method for accelerating the curing of an epoxy resin, characterized by curing by curing.