JPH07179566A - Epoxy resin - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin exhibiting liquid state at normal temperature and having decreased viscosity and excellent workability by epoxidizing bisphenol F composed mainly of p,p'-isomer and o,p'-isomer and having specific ratio of p,p'-isomer to o,p'-isomer. CONSTITUTION:This epoxy resin is produced by epoxidizing a bisphenol F having a p,p'-isomer/o,p'-isomer ratio of 35/65 to 60/40 and containing >=96wt.% of p,p'-isomer and o,p'-isomer in total usually by reacting with epichlorohydrin. The starting material, bisphenol F is preferably produced by recrystallizing 1 pt.wt of a bisphenol F consisting of a mixture of three kinds of structural isomers (o,o'-isomer, o,p'-isomer and p,p'-isomer) using 1 pt.wt. of toluene to obtain a high-purity bisphenol F containing p,p'-isomer and o,p'-isomer at 1/1 ratio and adding o,p'-isomer or p,p'-isomer to the obtained bisphenol F.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an epoxy resin,
More specifically, the present invention relates to a liquid epoxy resin having a lower viscosity at room temperature than conventional epoxy resins.

[0002]

2. Description of the Related Art Epoxy resins made from bisphenols are used in a very wide range of fields. Among such epoxy resins, the epoxy resin derived from 2,2-bis (4'-oxyphenyl) methane (hereinafter referred to as bisphenol F) is 2,2-bis (4'-).
(Oxyphenyl) propane) (hereinafter bisphenol A
Say. Since it has a remarkably low viscosity as compared with the conventional typical epoxy resin derived from (1), it is widely used for applications such as civil engineering, construction, and paints by taking advantage of its characteristics.

Low-viscosity epoxy resins are preferred because of their workability and product function as well as their safety and the ability to reduce the amount of highly toxic reactive diluents used. Market needs for such low-viscosity epoxy resins are persistent.

[0004] Bisphenol F is industrially used in order to suppress by-product of novolac, usually in the presence of an acid catalyst, a large excess (for example, 30 times molar amount) of phenol is reacted with formalin, and then excess. Of the phenol, which is produced as a residue recovered by distillation, and therefore the undistilled products of ordinary industrial products are o, o'-form, o, p'-form and p, p '. 90% or more in total of the three structural isomers of the body,
It consists of a mixture having a novolac content of 10% or less. At present, some of the distilled products obtained by distilling the above-mentioned undistilled products are sold in the market, but most of them are undistilled products. The epoxy resin derived from the distillate has a lower viscosity than the epoxy resin derived from the undistilled product because it does not contain the novolac component, but still has a viscosity of about 2200 centipoise at 25 ° C.

On the other hand, in the above-mentioned applications such as civil engineering, construction, paint, etc., the epoxy resin is usually 1000 at 25 ° C.
Since it is desirable to have a viscosity of up to 2000 centipoise (cps), it is necessary to dilute it with a reactive diluent to obtain the required viscosity, although the epoxy resin derived from the distillate has a low viscosity. Is.

Among the epoxy resins obtained from bisphenol F, the p, p'-form is known to have the lowest viscosity.
When left at 5 ° C), there is a drawback that the whole solidifies, and no method for selectively producing only the p, p'-form has been heretofore known. Epoxy resins derived from p, p'-forms have not been put to practical use because, for example, a method for efficiently separating only the p, p'-forms is not known.

The physical properties of the epoxy resin from bisphenol A and the conventionally known isomers of bisphenol F are shown in Table 1 ("Journal of the Adhesion Society of Japan", Vol. 26, No. 7, p. 29). (1990)).

[0008]

[Table 1]

[0009]

DISCLOSURE OF THE INVENTION The present inventors have earnestly conducted research in order to obtain an epoxy resin having a low viscosity which has never been obtained. First, the present inventors isolated each isomer from an undistilled product of bisphenol F, then prepared a mixture in which these isolated isomers were mixed in various combinations and ratios, and each of them was designated as epichlorohydrin. It was made to react and epoxidized to give an epoxy resin, and its viscosity was measured.

As a result, the o, p'-form of bisphenol F
It was found that the epoxy resin from the mixture of p, p'-forms had a significant decrease in viscosity, and the decrease in viscosity is shown in Table 1.
It was beyond the range predicted from. Furthermore, p, p '
The ratio of-body / o, p'-body is about 50% or more, preferably about 7
At 0% or more, the viscosity of the epoxy resin obtained is almost the same as the epoxy resin obtained from the p, p'-form of bisphenol F alone, and the viscosity of the epoxy resin obtained from the p, p'-form is It has been found that the drawback of solidifying at room temperature has been eliminated, and it remains liquid even when left at room temperature.

Furthermore, the present inventors have found that bisphenol F consisting of a mixture of the above-mentioned three kinds of structural isomers is converted into an o, p'-form.
As a result of earnest research on a method for efficiently separating only p, p'-forms, the above object can be achieved by a very simple method, and thus the epoxy resin according to the present invention can be industrially easily prepared. The inventors of the present invention have found that they can be obtained and have reached the present invention.

That is, an object of the present invention is to provide an epoxy resin which has a lower viscosity than the conventional epoxy resin and which is liquid at room temperature.

[0013]

According to the present invention, p, p'-
Obtained by epoxidizing bisphenol F containing 96% by weight or more of p, p'-form and o, p'-form having a ratio of body / o, p'-form of 35/65 to 60/40. A liquid epoxy resin having a low viscosity at room temperature is provided.

First, in order to selectively separate an o, p'-form and a p, p'-form mixture from bisphenol F consisting of a mixture of the above-mentioned three kinds of structural isomers, it is produced by a conventional method. Bisphenol F is recrystallized from an aromatic non-polar hydrocarbon solvent according to the present invention. Here, the bisphenol F
Is produced according to a conventional method, and may be a commercially available undistilled product or a distilled product. Examples of such an aromatic non-polar hydrocarbon solvent include benzene,
Toluene, xylene and the like can be mentioned, but among them, toluene is particularly preferably used from the viewpoint of operability.

In the above recrystallization of bisphenol F,
The amount of the solvent used is not particularly limited, but in consideration of the yield and the purity of the purified product by recrystallization, usually,
It is preferable to use about the same weight with respect to bisphenol F. For example, when toluene is used in the same amount with respect to bisphenol F, the yield of crystals of the mixture of o, p'-form and p, p'-form is about 70% of the charged amount of bisphenol F, F is present in the amount charged
It is about 90% of o, p'-form and p, p'-form.

According to this method, the remaining components of the three isomers of bisphenol F, the o, o'-form and the novolac component, have a solubility in toluene of o, p'-form and p, p'-form. Since it is significantly larger than the body, the recrystallized product obtained after recrystallization does not require special attention to the filtration conditions.
The ratio of the p, p'-body to the o, p'-body is about 1/1, and
The purity of the mixture of p, p'-form and o, p'-form in the purified product is 96-97%. In the present invention, as described above,
High-purity bisphenol F obtained by recrystallization of bisphenol F consisting of a mixture of the three structural isomers
(High-purity product containing p, p'-form and o, p'-form in about 1/1) is hereinafter referred to as bisphenol FC, which can be preferably used in the present invention.

In the present invention, the required amount of p, p'-form / o, p is added to the bisphenol FC obtained as described above by adding an appropriate amount of o, p'-form or p, p'-form simple substance. Raw materials having a'-body ratio can be prepared. In particular, in the present invention,
Bisphenol F having a p, p'-form / o, p'-form ratio of 35/65 to 60/40 and containing p, p'-form and o, p'-form in an amount of 96% by weight or more. Is preferably used as a raw material.

In the present invention, epoxidation of bisphenol F is carried out by reacting bisphenol F with epichlorohydrin according to a conventional method. For example,
Excess amount with bisphenol F (usually 5 times or more moles)
The epichlorohydrin of is preferably reacted in the presence of a catalyst (for example, tetramethylammonium chloride) for reaction to effect etherification, and then an aqueous alkali solution is added under reduced pressure to carry out a ring-closing reaction. After completion of the reaction, unreacted epichlorohydrin is removed under reduced pressure, an appropriate organic solvent (for example, toluene) is added to the residue to dissolve it, the salt produced as a by-product is filtered off, and then the organic solvent is reduced under reduced pressure. By distilling off to a residue, the desired epoxy resin can be obtained as a residue from the kettle.

Strictly speaking, the viscosity of the epoxy resin obtained from the p, p'-form and the o, p'-form of bisphenol F is p, p '
It decreases as the p'-body ratio increases, and the ratio becomes almost constant in the vicinity of about 50%. o, p'-body alone or p, p'-
The epoxy resin obtained from the simple substance solidifies at room temperature, but the epoxy resin obtained from the mixture in which the mixing ratio of the o, p'-form and the p, p'-form is about 1/1 is the most difficult to solidify, It remains liquid even when left at room temperature.

[0020]

The present invention will be described below with reference to examples.
The present invention is not limited to these examples.

Example 1 Undistilled product of bisphenol F (composition ratio (% by weight) p, p '/
o, p '/ o, o' / novolak = 34.13 / 43.04 / 14.4
100 g of 4 / 8.39) was added to 100 g of toluene, heated and dissolved, and then gradually cooled with stirring, and crystal precipitation started at 76 ° C. After cooling to 25 ° C., the crystals were filtered at that temperature, washed with toluene, dried and then dried under reduced pressure to obtain 71 g of bisphenol FC crystals.
Its composition (% by weight) is p, p '/ o, p' / o, o '/ novolac content = 45.12 / 51.50 / 1.41 / 1.98 (hence p,
p '/ o, p' is 47/53. )Met. In addition, 124.8 g of the filter washing liquid was obtained.

Example 2 The bisphenol F obtained in Example 1 was placed in a four-necked flask equipped with a thermometer, a stirring blade, a dropping device, and an outflow water condenser separator.
C 100 g (0.5 mol) and epichlorohydrin 462.6
g (5.0 mol), and as a catalyst, while stirring at 90 ° C. in the presence of tetramethylammonium chloride, 3
The etherification reaction was carried out for a period of time. Then, under reduced pressure (20
(0-300 mmHg) and 70 ° C. over 2 hours, 70.1 g (0.95 mol) of 48% aqueous sodium hydroxide solution was added dropwise to carry out the ring-closing reaction. Water and epichlorohydrin that had evaporated during this time were condensed, water was separated in a separator, and epichlorohydrin was returned to the reactor.

After completion of the reaction, unreacted epichlorohydrin was recovered under reduced pressure, toluene was added to the residue to dissolve the reaction product therein, and salt was removed by filtration. Then, toluene was distilled off under reduced pressure to obtain an epoxy resin as a bottom liquid. Yield 151.8g, viscosity (25 ° C) 1700 centipoise, epoxy equivalent 169, left at room temperature-
The refrigeration cycle was repeated, but it remained liquid at room temperature.

Example 3 In Example 2, as bisphenol FC, p, p'-
An epoxy resin was obtained in the same manner as in Example 2 except that bisphenol having a body / o, p'-body ratio of 55/45 was prepared and used. The composition ratio (% by weight) of the blended bisphenol FC is p, p '/ o, p' / o, o '/ novolac = 55.23 / 4
The obtained epoxy resin had a yield of 151.2 g, a viscosity (25 ° C.) of 1600 centipoise, an epoxy equivalent of 169, and was a liquid at room temperature.

Comparative Example 1 In Example 2, instead of bisphenol FC, p,
An epoxy resin was obtained in the same manner as in Example 2 except that the p'-body alone was used.

Comparative Example 2 In Example 2, instead of bisphenol FC, p,
An epoxy resin was obtained in the same manner as in Example 2 except that a mixture of 75 g of p'-body alone and 25 g of o, p'-body alone was used.

Comparative Example 3 In Example 2, instead of bisphenol FC, p,
An epoxy resin was obtained in the same manner as in Example 2 except that a mixture of 25 g of p'-body alone and 75 g of o, p'-body alone was used.

Comparative Example 4 In Example 2, instead of bisphenol FC, o,
An epoxy resin was obtained in the same manner as in Example 2 except that 100 g of the p'-body alone was used.

Comparative Example 5 An epoxy resin was obtained in the same manner as in Example 2, except that 100 g of undistilled bisphenol F was used in place of bisphenol FC.

Comparative Example 6 An epoxy resin was obtained in the same manner as in Example 2, except that 100 g of a bisphenol F distillation product was used in place of bisphenol FC.

The viscosities and epoxy equivalents at 25 ° C. of the epoxy resins obtained in the above Examples and Comparative Examples are shown in Table 2.
Shown in. Since the solidification temperature of the epoxy resin is very difficult to measure due to the effects of supercooling phenomenon and viscosity, in Table 2, the property column shows whether or not it solidifies at room temperature (25 ° C). .

[0032]

[Table 2]

As shown in Table 2, strictly speaking, the viscosity of the epoxy resin obtained from bisphenol F decreases as the ratio of the p, p'-form increases, and is almost constant when the ratio is around 50%. Becomes Epoxy resin obtained from o, p'-form or p, p'-form alone solidifies at room temperature,
The epoxy resin obtained from the mixture in which the mixing ratio of the p'-form and the p, p'-form is about 1/1 is a liquid at room temperature.

[0034]

The epoxy resin according to the present invention has a p, p'-form / o, p'-form ratio of 35/65 to 60/40 in the range of p, p'-form and o, p '. A body obtained by epoxidizing bisphenol F containing 90% by weight or more of
At 0 ° C, the viscosity is less than 2000 centipoise, and it does not solidify at room temperature and remains liquid. Therefore, such an epoxy resin not only reduces the amount of the reactive diluent unfavorable for safety and hygiene, or makes the use unnecessary, but also improves workability in civil engineering, construction sites, etc. be able to.

Front Page Continuation (72) Inventor Haruo Kasamatsu 2-115 Kosiga, Wakayama Honshu Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] 1. The ratio of p, p'-form / o, p'-form is 35/65.
A low-viscosity liquid epoxy resin at room temperature obtained by epoxidizing bisphenol F containing 96% by weight or more of p, p'-form and o, p'-form in the range of 60/40.