CN1025432C - A kind of method for preparing epoxy compound - Google Patents

Abstract

A novel epoxy compound has an aromatic ring in its chemical structure, to which a glycidyl group and a tertiary alkyl group in an ortho or meta position are connected. An epoxy resin composition comprises the epoxy compound, a curing agent and a curing accelerator, and the product cured by the composition has a lower dielectric constant.

Description

The present invention relates to a method for preparing an epoxy compound and an epoxy resin composition containing the epoxy compound.

Cured epoxy resins are widely used as electrical insulating materials, adhesives and coating compositions due to their improved electrical properties, adhesive properties and heat resistance properties. However, since the application of epoxy resin in advanced fields, especially in electrical and electronic applications, needs to meet stringent requirements, its thermal resistance, mechanical properties and electrical properties need to be further improved.

Examples of epoxy resins known to form cured products with higher heat resistance are epoxy o-cresol novolac (EOCN) and epoxy novolac phenol, however cured products of these epoxies still exist Fragility problem.

In addition to the problems of brittleness and low flexibility of cured epoxy resins, when improving their heat resistance, their flexibility is often further reduced, and the lack of flexibility will lead to many problems, for example, the coating formed by the coating composition It is easy to break under the action of impact force, and cannot reach the required level of peel strength when used as an adhesive, and the casting made of the casting composition is also easy to break under thermal shock.

Known epoxy resins having improved flexibility are polyalkylene glycol diglycidyl ethers, lactone-modified epoxy resins, and the like. Despite the improvement in flexibility, cured articles of these resins suffer from a decrease in other properties including heat resistance and mechanical strength. Epoxy resins need to have sufficient heat resistance and flexibility to meet the requirements for their application in advanced fields.

In the field of laminate applications, in order to improve the encoding speed of the computer, it is necessary to have a low dielectric constant. As current fine patterning and densification techniques for increasing computer encoding speeds have nearly reached their physical limits, attention is now focused on finding another way to lower the dielectric constant of the plate material. Polyethylene and fluororesin are recommended as materials with a low dielectric constant. But most of these material resins have the disadvantages of low mechanical strength, poor dimensional stability and low copper foil peel strength.

Replacing the glass substrate with quartz has also been considered, but the attendant problem is that the drill bit used to perforate the substrate will be severely worn.

For an epoxy resin, a necessary condition that should have is to reduce its dielectric constant, but still maintain the original performance of epoxy resins.

It is an object of the present invention to provide a novel epoxy compound capable of constituting cured epoxy resins which have a lower dielectric constant than conventional epoxy resins while still maintaining improved heat resistance and softness.

Another object of the present invention is to provide an epoxy resin composition comprising the epoxy compound as an essential component.

According to a first aspect of the present invention, the epoxy compounds provided herein have the general formula:

Wherein n is the number of repeating units, its value is 0～30,

R ¹ , R ² and R ³ are optionally selected from hydrogen and alkyl groups having 1 to 6 carbon atoms,

R ⁴ is a tertiary alkyl group.

According to a second aspect of the present invention, an epoxy resin composition provided herein comprises an epoxy compound having the following general formula, A curing agent and a curing accelerator.

Wherein n is the number of repeating units, its value is 0～30,

R ¹ , R ² and R ³ are optionally selected from hydrogen and alkyl groups having 1 to 6 carbon atoms,

R ⁴ is a tertiary alkyl group.

Figures 1 and 2 are ₁ H NMR and IR spectra showing typical epoxy compounds of the present invention.

Epoxy compound of the present invention is the compound of a kind of novel chemical structure, wherein has a tertiary alkyl on the aromatic ring of glycidyl, for example, tertiary butyl, it is preferably as shown in molecular formula (A), Ortho to the glycidyl group.

In the molecular formula (A), R ¹ , R ² and R ³ are optionally selected from a hydrogen atom and an alkyl group having 1 to 6 carbon atoms. ^R1 is preferably hydrogen or methyl, ^R2 is preferably methyl or ethyl or propyl, ^R3 is preferably methyl or ethyl, especially attached to the aromatic ring at the meta position between adjacent oxygen atoms On, R ⁴ is a tertiary alkyl group, preferably tert-butyl, especially attached to the aromatic ring at the ortho position of the adjacent oxygen atom.

The epoxy resin composition of the present invention contains the above-defined epoxy compound as an essential component, and further contains a curing agent and a curing accelerator. Due to the steric hindrance phenomenon caused by the tertiary alkyl group in the epoxy compound unit, the epoxy compound is cured to a resin with a low dielectric constant when compared with the curing epoxy resins known in the prior art, and the The resin has also been improved in heat resistance and flexibility.

The epoxy compound of molecular formula (A) can be prepared by the reaction of bisphenol and epichlorohydrin in general formula (I), and its proportioning is that every mole of bisphenol will add 3～30 moles of epichlorohydrin.

wherein R ¹ to R ⁴ are as defined in formula (A). Preferred examples and connection positions of the substituents R ¹ to R ⁴ are as described above.

This reaction can be carried out by various methods known in the prior art for similar reactions. One method of reacting bisphenols with epichlorohydrin is to use an alkaline compound such as sodium hydroxide, potassium hydroxide and lithium hydroxide, preferably sodium hydroxide, in the presence of water, which The amount used is at least one mole of alkali compound per equivalent of phenolic hydroxyl group of bisphenol, preferably 1.02-1.05 moles of alkali compound, and the reaction temperature is about 60-90°C. During the reaction, etherification and dehydrohalogenation also occur simultaneously. At the end of the reaction, unreacted halohydrin, water and salt formed are removed from the reaction mixture, and then the reaction product epoxy compound is dried and recovered.

It is also possible to use an alternative method in which etherification and dehydrohalogenation are carried out sequentially rather than simultaneously, which has the advantage of obtaining epoxy resins of stable quality.

In the stage of etherification reaction, about 0.005-5 mol% of etherification catalyst is added per equivalent of phenolic hydroxyl group of bisphenol to carry out etherification reaction. Some examples of etherification catalysts include tertiary amines such as trimethylamine and triethylamine; tertiary phosphines such as triphenylphosphine and tributylphosphine; quaternary ammonium salts such as tetramethylamine chloride, tetramethylamine bromide, tetramethylammonium chloride Ethylamine, tetraethylamine bromide, and choline hydrochloride; quaternary phosphonium salts, such as tetramethylphosphonium bromide, tetramethylphosphonium iodide, and triphenylpropylphosphonium bromide, and tertiary sulfonium salts, such as benzyl chloride Dibutylsulfonium and benzyldimethylsulfonium chloride, among which quaternary ammonium salts are ideal. The etherification reaction continues until at least about 50%, preferably at least about 80%, of the bisphenol hydroxyl groups are etherified. This reaction is usually carried out at a temperature of about 60-110°C for about 1-12 hours. Although the reaction can be carried out in the presence of water, it is preferably carried out in the absence of water. If water is present, then it is best to control the amount of water to about 3% (by weight) of the reaction mixture.

The subsequent dehydrohalogenation stage can be started from the reaction product of the etherification stage itself, ie it is not necessary to remove unreacted epihalohydrin. The reaction is carried out in the presence of a catalyst, which may be an alkali compound, such as an alkali metal hydroxide, as in the simultaneous etherification/dehydrohalogenation process, preferably using sodium hydroxide in an amount of Yes, the base compound is used in an amount of at least about 0.5 moles, preferably about 0.8 moles, per equivalent of phenolic hydroxyl groups of bisphenols. In order to avoid unfavorable gelation, the amount of the alkali compound is preferably limited to 1 mole.

The reaction is usually carried out at a temperature of about 60-100°C 1 to 3 hours, when the catalyst used is sodium hydroxide, it is best to carry out the reaction under the condition of removing the by-product water in the reaction system.

Unreacted epihalohydrin is then removed by vacuum stripping, by-product salts are removed by water washing, optionally neutralized with a mild acid, such as phosphoric acid and sodium dihydrogen phosphate. The final product epoxide is then dried and recovered.

When the novel epoxy compound of the present invention prepared in this way is used for lamination, its epoxy equivalent weight (EEW) is 200～2000, is preferably 230～1500, and its softening point is 45～130 ℃ and is preferably 55～2000. 110°C.

Shown below is a typical example of the novel epoxy compound of the present invention and its properties.

name:

1,1-bis(2-methyl-4-hydroxy-5-tert-butyl)butane

Chemical Structure:

NMR analysis:

Figure 1 is the ¹ H-NMR spectrum of this compound.

δ (ppm) (TMS standard)

7.08 S2 protons

6.53 S2 protons

3.75～4.25 m4 protons

3.10～3.50 m2 protons

2.60～3.0 m4 protons

2.20 S6 protons

0.75～2.10 m8 protons

1.3 S18 protons

Infrared spectral analysis:

Fig. 2 is the infrared spectrogram of this compound.

The softening point of this compound is about 60°C.

The epoxy resin composition of the present invention comprises a novel epoxy compound as defined above, a curing agent and a curing accelerator. The epoxy resin composition can be cured into a product having the following advantages. (1) The heat resistance of the cured product is improved due to the lowered fluidity due to the presence of the bulky tertiary alkyl group represented by R ⁴ . (2) Since the cured product is internally plasticized by the alkyl groups represented by R ¹ , R ² and R ³ , it is soft. (3) The cured product has a lower dielectric constant because of the presence of those alkyl groups having many methyl groups represented by R ¹ to R ⁴ .

The curing agent contained in the epoxy resin composition of the present invention includes, but is not limited to, acid anhydrides, aromatic polyamines, aliphatic polyamines, imidazoles and phenolic resins.

Some examples of acid anhydrides include, phthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnorbornenedioic anhydride, 1, 2,4,5-Pellimetic anhydride, 1,2,4-Pellimetic anhydride, Diphenone tetracarboxylic anhydride, Lauryl succinic anhydride and Chlorobacillus anhydride.

Some examples of aromatic polyamines include diaminodiphenylmethane, diaminodiphenylsulfone, and amine adducts.

烯二胺、N-氨乙基哌嗪、异佛尔铜二胺、3，9-双（3-氨丙基）-2，4，8，10-四螺[5，5]十一烷和胺加合物。Examples of aliphatic polyamines include triethylenetetramine, diethylenetriamine,

Enediamine, N-aminoethylpiperazine, isophorcopperdiamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro[5,5]undecane and amine adducts.

Some examples of phenolic resins include phenolic resins and alkyl substituted phenolic resins.

Other useful curing agents are dicyandiamide and m-xylylenediamine.

Some examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-ethyl-4-methylimidazolazine, and 1 -Benzyl-2-methylimidazole.

The curing accelerator included in the epoxy resin composition of the present invention includes imidazoles and tertiary amines represented below.

Some examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-ethyl-4-methylimidazolazine, and 1 -Benzyl-2-methylimidazole.

Some examples of tertiary amines include N,N-benzyldimethylamine and 2,4,6-tris(dimethylaminomethyl)monophenol.

Other useful curing accelerators are 1,8-diazabicyclo-(5,4,0)+monocyne-7 octanoate (which is commercially available under the trade name UcatSA102 from Sun Abot Corporation). products), and complexes of mono-2 base ammonia and boron trifluoride.

The epoxy resin composition of the present invention may also contain some Other epoxy compounds that do not have an adverse effect on the intended purpose of the composition. Examples of other epoxy compounds used here are bisphenol-A epoxy compound, bisphenol-F epoxy compound, 1,1-bis(glycidylhydroxyphenyl)ethane, phenol novolac (resin) type epoxy Compounds, o-cresol novolac (resin) type epoxy compounds, glycidyl ester type epoxy compounds, glycidylamine type epoxy compounds and cycloaliphatic epoxy compounds. When it is necessary to impart flame retardancy to the cured epoxy resin composition of the present invention, tetrabromobisphenol-A-diglycidyl ether or a similar flame retardant can be used in the composition.

When phenol novolac epoxy resin, particularly o-cresol-novolac epoxy resin was mixed with epoxy resin of the present invention, epoxy resin composition of the present invention can be more heat-resistant, and its consumption is every 100 parts (according to By weight) in the epoxy resin of the present invention, add 0～30 parts, preferably 0～20 parts (by weight) of novolak type epoxy resin.

In the epoxy resin composition of the present invention, in addition to containing the above components, it can also contain an appropriate amount of any additive, for example, non-reactive diluents, such as phthalates, (ethylene) glycol ethers and esters, and phenols; reactive diluents, such as long-chain alkylene oxides, butyl glycidyl ether, phenyl glycidyl ether, and p-butylphenyl glycidyl ether; fillers, such as calcium carbonate, clay , asbestos, silica, mica, ground quartz, aluminum powder, graphite, titanium oxide, alumina, iron oxide, glass powder, and glass fiber; and colorants such as carbon black, toluidine red, Hansa yellow, phthalocyanine semi-and Phthalo green.

The components contained in the epoxy resin composition of the present invention preferably adopt the following ratio: that is, about 1 to 150 parts are added in the epoxy resin per 100 parts (by weight), preferably 3 to 110 parts ( (by weight) of curing agent and about 0.1 to 3 parts (by weight) of curing accelerator. When the curing agent is dicyandiamide, a smaller amount can be used.

The epoxy resin composition of the present invention is prepared by mixing these components by heating them to melt or dissolving them in a solvent.

The epoxy resin composition of the present invention can be cured at room temperature or by heating it to a temperature of about 60-250°C.

Some examples are given below as specific descriptions of the present invention, but the present invention is not limited thereto.

Example 1

393.8 grams of 1,1-bis(2-methyl-4-hydroxyl-5-tert-butylphenyl) butane, 1221 grams of epichlorohydrin and 33 grams of water were injected into a stirrer, reflux condenser, The dropping funnel and thermometer were placed in the reactor, and the ingredients were then heated to 70°C. After 1,1-bis(2-methyl-4-hydroxy-5-tert-butylphenyl)butane was dissolved, 1.2 g of an aqueous solution containing 53.2% (by weight) tetramethylamine chloride was added to In the above-mentioned butane solution, it was stirred at a temperature of 70°C for 2 hours. Then, under vacuum, 169.6 grams of 48% sodium hydroxide aqueous solution was added at 70° C. over a period of 2 hours, and during these two hours, 36.6 grams of sodium hydroxide was removed from the reaction system by azeotropic distillation of epichlorohydrin. grams of water. The distilled epichlorohydrin is then separated from the water and sent back to the reaction system. The vacuum degree of this reaction system is controlled like this, promptly per unit time removes the water amount from this system and should equal the water amount in the sodium hydroxide solution that adds and the sum of the water amount that reacts to generate.

After adding the above amount of sodium hydroxide solution, the reaction mixture was stirred for a further 1/2 hour at the above temperature. This completes the first ring-closing reaction.

Then, unreacted epichlorohydrin and water were distilled off under vacuum. To the residue were added 634.6 g of methyl isobutyl ketone and 377 g of water. The mixture was stirred at a temperature of 95° C., then left to stand, and separated into an organic phase and an aqueous phase. A sample was taken from the organic phase and analyzed after removal of the solvent, and the concentration of hydrolyzable chlorine was found to be 0.58% by weight.

The organic phase was charged to the reactor and heated to 90°C followed by the addition of 9.8 g of an aqueous solution containing 48% by weight of sodium hydroxide which was 1.5 times the molar content of hydrolyzable chlorine. The reaction mixture was stirred at a temperature of 90° C. for 2 hours to carry out the second ring closure reaction. At the end of the reaction, 70.4 g of an aqueous solution containing 30% by weight of sodium dihydrogenphosphate was added to neutralize the reaction solution, and the organic phase was separated from the reaction solution.

Water was azeotropically distilled off from the organic phase and filtered through a glass filter to remove inorganic salts. Methyl isobutyl ketone was distilled off from the filtrate under vacuum to yield 485 g of a clear glycidol product. The resulting epoxy compound had a softening point of 60°C, an epoxy equivalent weight of 307 g/eq, a hydrolyzable chlorine concentration of 0.015% by weight, and a repeating unit number n of 0.27.

Example 2

Inject 213.8 grams of 1,1-bis(2-methyl-4-hydroxyl-5-tert-butylphenyl) butane, 663 grams of epichlorohydrin and 21 grams of water in the reactor, then heat the contents, when the reaction system becomes After getting uniform, add 1.2 grams of aqueous solution containing 53.2% tetramethylammonium chloride. Stirring was continued for 6 hours at a temperature of 70°C and then for a further 2 hours at 80°C.

Except before the start of the second ring-closing reaction, in the reaction mixture The hydrolyzable chlorine concentration is 0.61% (by weight), and then the procedure carried out is identical with embodiment 1.

Thus, 247 g of a transparent glycidol product, i.e., an epoxy compound, having an epoxy equivalent weight of 300 g/equivalent, a hydrolyzable chlorine concentration of 0.007% by weight and a repeating unit n of 0.24 was obtained.

Example 3

Preparation of epoxy resin composition: 100 parts (by weight) of the epoxy compound prepared in Example 1, 55 parts (by weight) of methyl hexahydrophthalic anhydride curing agent (Shin- Liqacid MH-700 manufactured by Nihon Rika K.K.) and 0.5 parts (by weight) of 1,8-diazabicyclo-(5,4,0)undecene-7 octanoate curing accelerator (Sun Abot UcatSA102 produced by the company) were mixed and then heated. Finally, the composition was cast into a casting mold, cured at 100°C for 1 hour, at 120°C for 2 hours, at 150°C for 2 hours, and then at 170°C for 4 hours to obtain a cured epoxy resin.

The physical properties of the cured epoxy resin are shown in Table 1.

Comparative Examples 1 and 2

The preparation of curing epoxy resin is except that in comparative example 1, the epoxy compound that does not make in embodiment 1 is replaced with the bisphenol-A epoxy resin that epoxy equivalent (weight) is 189 (gram), comparative example 2 Also do not use the epoxy compound that embodiment 1 makes and replace with epoxy equivalent (heavy) and be 209 (grams) (EOCN103s, Nihon Kayaku K.K. produce) outside the o-cresol novolac epoxy resin, other technological process Same as Example 3. In addition, the epoxy compound is mixed with methyl hexahydrophthalic anhydride curing agent and 1,8-diazabicyclo (5,4,0) undecene-7 octanoate curing accelerator in the ratio shown in Table 1. mix.

The physical properties of the cured epoxy resin are listed in Table 1.

See Table 1 after the text

Example 4

Preparation of a homogeneous solution: mixing 29 parts (by weight) of the resin of Example 1 and 20 parts (by weight) of p-tert-octylphenol novolak resin with a softening point of 116° C. and an OH equivalent of 214 g/equivalent, The mixture was debubbled at -150°C. 0.14 parts by weight of 2-methylimidazole were added to the solution at this temperature. The mixture is further stirred and freed of air bubbles, and then cast into casting molds.

The mixture was cured at 150°C for four hours and then at 170°C for four hours.

The cured resin exhibits the following physical properties.

Glass transition temperature 150°C

Dielectric constant at 1MHz 2.7

Dielectric loss factor at 1MHz 0.011

Example 5

Preparation of a homogeneous solution: mix 38 parts (by weight) of the resin of the embodiment and 30 parts (by weight) of p-nonylphenol novolac resin with a softening point of 72°C and an OH equivalent of 250 g/equivalent at 120 °C to remove air bubbles from the mixture. 0.18 parts by weight of 2-methylimidazole were added to the solution at this temperature. The mixture is further stirred and freed of air bubbles, and then cast into casting molds.

The mixture was cured at 120°C for 3 hours, at 150°C for 2 hours, and at 170°C for 4 hours.

The cured resin exhibits the following physical properties;

Glass transition temperature 120°C

Dielectric constant at 1MHz 2.8

Dielectric loss factor at 1MHz 0.008

Example 6

Preparation of paint composition: uniformly mix 1070 parts (by weight) of the resin of Example 1, 713 parts (by weight) of p-tert-octylphenol with a softening point of 116°C and an OH equivalent of 214 g/equivalent Phenolic resin, 10 parts by weight of 2-ethyl-4-methylimidazole and 560 parts by weight of toluene.

Preparation of prepreg: glass fiber (6232/1050/AS450 produced by Asahi Shuebell K.K. company) is impregnated with paint composition, and then dried to obtain prepreg.

The laminate was fabricated as follows: 15 prepregs prepared as described above were stacked one on top of the other, and molded at a pressure of 10 kg-f/cm ² and a temperature of 180°C for 60 minutes.

The resulting laminates exhibit the following properties:

Resin content (weight%) 41.1

Glass transition temperature (°C) 150°C

Bending strength (kg-f/mm ² ) 51

Flexural modulus (kg-f/mm ² ) 1940

Dielectric constant at 1MHz 3.4

Dielectric loss factor at 1MHz 0.0065

The above data clearly show that the cured epoxy resin obtained by curing the epoxy resin composition of the present invention has heat resistance due to the reduction of fluidity, and the reduction of fluidity is due to the connection on the benzene ring caused by the bulky tertiary alkyl group represented by R ⁴ . In addition to heat resistance, the cured resin has a low (flexural) modulus and is soft due to the internal plasticizing effect of the alkyl groups represented by R ¹ , R ² and R ³ , and due to R ¹ ~ The alkyl group represented by R ⁴ is mostly methyl so that the cured resin has a low dielectric constant.

The novel epoxy compound of the present invention is useful to the preparation of a kind of epoxy resin composition, after this epoxy resin composition is cured compared with conventional bisphenol-A type epoxy resin and o-cresol novolac epoxy The resin has satisfactory heat resistance, flexibility and low dielectric constant.

Cured products made from the epoxy resin composition of the present invention have very good heat resistance when used as sealing materials or insulating coatings in the electrical and electronic fields, and are cured epoxy resins with minimal brittleness and low dielectric constant Used for many purposes.

From the above description it will be evident that several modifications and variations of the present invention are possible. It is therefore to be noted that, within the scope of the appended claims, the invention may be practiced otherwise than as defined herein.

Table 1

E3 CE1 CE2

Parts of composition (by weight)

epoxy compound

Example 1 100 - -

Comparative example 1 - 100 -

Comparative example 2 - - 100

Curing agent 55 86 75

Curing Accelerator 0.5 0.5 0.5

Curing Physical Properties

Glass transition temperature ^*1 (°C) 178 156 186

Bending strength ^＊2 (kg-f/mm ² ) 12.8 13.0 12.8

Flexural modulus ^＊2 (kg-f/mm ² ) 260 290 340

Dielectric constant ^＊2 2.9 3.3 3.4 at 1KHZ

When the dielectric loss factor is 1KHZ 0.0104 0.007 -

_*1 Differential scanning calorimeter

^*2 Japanese Industrial Standard (JIS) K6911.

Claims (1)

1. A method for preparing an epoxy compound of formula (A), comprising: Bisphenol is reacted with epichlorohydrin in a ratio of adding 3 to 30 moles of epichlorohydrin per mole of bisphenol, Wherein bisphenol available formula (I) represents:

Wherein n is the number of repeating units, its value is 0-5, ^R1 is hydrogen, ^R2 is n-propyl, ^R3 is methyl, and ^R4 is t-butyl.

Images