JPS6045211B2 - One-component epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a one-component epoxy resin composition having excellent stability at room temperature.

Generally, epoxy resins are mixed with a curing agent or catalyst and cured by heating or at room temperature. However, this mixed system is extremely unstable and tends to undergo undesirable gelation and hardening before it is used. The so-called reappointment time is short.

Specifically, for example, in the case of a so-called two-component epoxy resin composition, when a curing agent is added to the epoxy resin, the pot life is only a few minutes to a few days, so the two must be mixed each time they are used. Therefore, there are problems such as complicated measuring and mixing, measuring errors, and losses.Therefore, a so-called one-component product is desired, in which curing does not proceed even if a curing agent is added in advance. In order to make an epoxy resin composition into a single component, the curing agent must have an indefinite pot life and must have so-called latent ability, which means that it can be quickly hardened by the application of some stimulus, such as heat. Conventionally, dicyandiamide, melamine, and benzoguanamine are known as latent curing agents for epoxy resins, but these have too high a curing temperature and too long curing time, so they are difficult to cure with tertiary amines, aromatic oxy compounds, etc. Concomitant use of accelerators is essential. Therefore, storage stability naturally deteriorates, and satisfactory stability cannot be obtained as a one-component product. Lewis acid-amine complexes are also known as typical latent curing agents, but they are difficult to put into practical use because they are irritating to the skin and corrosive to metals. Further, boron fluoride-amine complex compounds are also known as latent curing agents, but these also have skin irritation and metal corrosiveness, which poses problems in practical use. Furthermore, as another latent curing agent for epoxy resins, it has been proposed in US Pat. No. 3,639,657 to use a reaction product of an acid anhydride and an amine as it is. Although this curing agent does have latent properties and a relatively low curing temperature, its pot life is not satisfactory as a one-component product. Furthermore, recently, unique latent curing agents different from the above-mentioned types have been described in JP-A-52-799 and JP-A-52-589, but when these curing agents are mixed with epoxy resin, Curing progresses gradually even at room temperature, and long-term stability cannot be expected. The purpose of the present invention is to improve the above-mentioned drawbacks, to provide a one-component epoxy resin that has long-term storage stability and pot life, can be supplied in the form of a curing agent mixed in advance with an epoxy resin, and has excellent latent curing properties. An object of the present invention is to provide an epoxy resin composition.

The present invention aims to achieve the above object, and includes 100 parts by weight of an epoxy resin and 1 to 10 parts by weight of a compound having a carboxylic acid amide bond and a carboxylic acid metal salt bond in one molecule as a curing agent. A one-component epoxy resin composition comprising:

That is, the present invention provides an improved one-component epoxy in which a compound obtained by reacting an organic carboxylic acid anhydride with an amine and deriving the carboxyl group of the reaction product into a metal salt is used as a latent curing agent for an epoxy resin. It is a resin composition. The present invention will be explained in detail below.

Intramolecularly condensed acid anhydrides used in the practice of the present invention include monofunctional anhydrides and polyfunctional anhydrides.

Examples of monofunctional anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, dodecenyl succinic anhydride, 1-methylhexahydrophthalic anhydride, maleic anhydride, etc. There is. Examples of polyfunctional anhydrides include pyromellitic anhydride, trimellitic anhydride, and polyazelaic anhydride. These anhydrides may be used alone or in combination of two or more. The amines used in the practice of the present invention are preferably primary and secondary amines, and both aliphatic amines and aromatic amines are used.

Examples of amines used include ethylenediamine, aniline, hexamethylenediamine, m-phenylenediamine, p-phenylenediamine, dimethylamine, diethylamine, di-n-propylamine, diisobutylamine, di-2-ethylhexylamine, piperidine, Piperazine, pyrrolidine, pyrazoline, ethyleneimine, indole, imida, zole, benzimidazole, N-alkylaniline, N-methyl-N-cyclohexylamine, dicyclohexylamine, diphenylguanidine, etc. can be used. These amines can be used alone or in combination of two or more. In the present invention, the active hydrogen of the carboxyl group of the reaction product of the acid anhydride and the amine is replaced with a metal and stabilized as a metal salt.

As the metal compound used in this case, metal hydroxides, halides, etc. are preferably used. Monovalent metals include sodium, potassium, lithium, etc., divalent metals include magnesium, calcium, copper, zinc, cobalt, nickel, iron, tin, titanium, manganese, etc., and trivalent metals include aluminum, Examples include iron. The metal compounds can be used alone or in combination of two or more. Furthermore, the epoxy resin used in carrying out the present invention is not particularly limited. The epoxy resin usually has two or more epoxy groups in one molecule, is blended with the above-mentioned metal salt, and cures and becomes insoluble and infusible only when exposed to heat or other stimuli. For example, the reaction products of epichlorohydrin and 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), those derived from aliphatic polyglycidyl ethers of polyalcohols, resorcinol and diphenol-poly(hydroxyphenyl)- These include reaction products of pentadecane and epichlorohydrin, and epoxidized novolak compounds (novolak type). Epoxy resins are used as structural materials, electrical insulation materials, adhesives, casting materials, coating materials, paint materials, etc.

In the present invention, a one-component epoxy resin composition is prepared by dispersing and mixing a metal salt as a latent curing agent prepared as described above into an epoxy resin. The amount of the latent curing agent to be mixed is preferably 1 to 100 parts by weight per 10 parts by weight of the epoxy resin. In the present invention, other additives may be blended as long as they do not interfere with the effects of the present invention.

The curing agent according to the present invention does not have the ability to chemically attack epoxy groups at room temperature, unlike conventional epoxy curing agents.

The one-component epoxy resin composition of the present invention cures relatively quickly only when stimulated by heating, etc., and is not only stable at room temperature, but also exhibits no change in viscosity even when left at 50'C for a long period of time. It has the advantage that it cannot be seen and therefore there is no need to be careful about its storage. This means that it is easy to handle as it is a one-component product, and it is also very easy to store, meaning that it can be stored for a long time as a one-component product and has the advantage of extending its pot life, which has a great effect on expanding its uses. The present invention will be explained in more detail below using examples.

Parts in the examples are parts by weight unless otherwise specified. Example 1 740q (5 moles) of phthalic anhydride was dissolved in 1500q of dimethylaceamide, and 440y (5.2 moles) of piperidine was gradually added dropwise with stirring so that the temperature did not rise above 50°C.

A 17% aqueous solution of sodium hydroxide was added to the resulting reaction solution.
As 200yCNa0H, (1200X0.17) ÷
40=5.1 mol] was added dropwise and reacted. Zinc chloride 340y (2.5 mol) was added to this reaction product, and the resulting product was purified with ethanol to obtain white powder A. The above reaction is expressed as follows.

That is, a compound (white powder A) having a carboxylic acid amide bond and a carboxylic acid metal salt (zinc salt) bond in one molecule.
) is formed.

This white powder A was thoroughly mixed with 1 (1) part of four types of epoxy resin at each mark, and heat treated at 145° C. for 1 hour, and the hardness is shown in Table 1.

* EPikOte 812, EPikOte 82, EPikOte 1001 and EPikOte 100
4 are all trade names of epoxy resins manufactured by Shell, Inc., and Epicote 828 is a typical bisphenol A/Epic rehydrin type epoxy resin (used in the following examples as well).

Further, when the epoxy resin composition before heat treatment was left at room temperature, no substantial change indicating an increase in viscosity was observed even after one year.

Example 2 A curing agent was prepared using the same synthesis method as in Example 1 using morpholine as the amine and various acid anhydrides and zinc chloride shown in Table 2.

Each 50V of the obtained zinc salt was added to Epicote 828-100q.
No change in viscosity was observed even after one year in the case of the mixture.

Table 2 shows the amount of each compound used in the reaction and the curing conditions and hardness of the cured product when using the obtained zinc salt. Example 3 In the same manner as in Example 1, zinc salts were synthesized using zinc chloride and tetrahydrophthalic anhydride as the acid anhydride for various amines shown in Table 3, and Epicote 828-100y was synthesized.
In addition, 50y of zinc salt was thoroughly mixed, and the obtained results are shown in Table 3 below.

For example, the following reaction product (zinc salt) can be obtained from hyperazine. Example 4 740y of phthalic anhydride was mixed with 1500y of dimethylacetamide
440q of piperidine was gradually added dropwise and stirred so as not to rise above 50'C.

A 17% aqueous solution of sodium hydroxide was added to the resulting reaction solution.
200q was dropped and reacted. This reaction product was thoroughly washed with acetone to obtain white powder B. When this was added to various epoxy resins as in Example 1, almost no change in viscosity was observed even after 6 months. Table 4 shows the curing conditions and hardness of the sodium salt resin mixed with various epoxy resins.

Example 5 Sodium salts of various acid anhydrides shown in Table 5 were synthesized using the same synthesis method as in Example 4 (the amine was piperidine).

Each part of the obtained sodium salt was Epicoat 828-
When 1 (4) parts were mixed well, almost no change in viscosity was observed for more than 6 months. Table 5 below shows the results of 4 parts of each of the sodium salts obtained here mixed well with 828-100 parts of Epicoat and cured at 140 DEG C. for 1 hour. Example 6 In the same manner as in Example 1, sodium salts of various amines listed in Table 6 were synthesized, and 4 parts of each sodium salt were thoroughly mixed with Epicote 828-100q. However, no change in viscosity was observed.

In addition, each sodium salt 5@S was added to Epicote 828-100.
Table 6 below shows the results obtained by thoroughly mixing the mixture and curing it at 150° C. for 1 hour. For example, with piperazine, the sodium salt is obtained by the following reaction.

Example 7 480 d of trimellitic anhydride was dissolved in 1,000 f of ethanol, 220 y of piperidine was gradually added dropwise without the temperature rising above 40°C, and 1,000 d of trimellitic anhydride was dissolved in the reaction solution.
200 y of potassium hydroxide dissolved in y of water was added dropwise for reaction.

After water and ethanol in the reaction solution were distilled under reduced pressure, the potassium salt was thoroughly washed with acetone. When the obtained potassium salt-added part was thoroughly mixed with 828-100 parts of Epicote, almost no change in viscosity was observed even after 6 months at room temperature.

Further, when heat treated at 140'C x 1 hr, a cured product with a D hardness of 90 or more was obtained. Example 8 Dissolve 740y of phthalic anhydride in 1000 da of acetone,
360 y of diethylamine was gradually added dropwise at room temperature, and 200 y of sodium hydroxide dissolved in 1000 q of water was added dropwise to the reaction solution to react.

This reaction product was reacted with 670y of cupric chloride, and the resulting reaction product was thoroughly washed with acetone to obtain a white powder. Add 1 (1) part of this copper salt to 1 (1) part of Epikote 828
), no change in viscosity was observed even after one year. Further, when heat treated at 180° C. for 511 r, a cured product with a D hardness of 60 was obtained. Example 9 Phthalic anhydride 740y was dissolved in 1000g of acetone, and 44
0f of piperidine was gradually added dropwise while cooling with water, and sodium hydroxide 2 dissolved in 1000q of water was added to the reaction solution.
00 da was dropped and reacted.

This reaction product contains nickel chloride (NiCl2.6H20).
) 1035y was gradually added, and the resulting reaction product was thoroughly washed with acetone. This one is Epicoat 828-1
No change in viscosity was observed even after one year at room temperature when 10 parts by weight were mixed well with 0 parts by weight. Further, when heat treated at 180° C. for 5 hours, a cured product with a D hardness of 70 was obtained. Example 10 370 g of phthalic anhydride was dissolved in 1000 q of methanol, and 218 q of morpholine was gradually added dropwise to react without raising the temperature above 40°C.

Claims (1)

[Claims] 1 100 parts by weight of epoxy resin and 1 as a hardening agent
A one-component epoxy resin composition comprising 1 to 100 parts by weight of a compound having a carboxylic acid amide bond and a carboxylic acid metal salt bond in the molecule.