JPS6055535B2 - liquid epokine resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid epoxy resin produced by reacting liquid carboxyl polyether or polyester with a liquid epoxy compound.

Epoxy resin has excellent adhesive properties, electrical, mechanical,
Due to its chemical properties and wide range of curing methods that can be performed from room temperature to high temperatures, it is widely used in adhesives, paints, molding materials, civil engineering and construction materials, electrical parts, etc.

The curing method is one based on amine compounds such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, etc., which can be cured at room temperature, and one based on acid anhydrides such as anhydrous. Typical examples include those cured by heat using maleic acid, phthalic anhydride, hexahydrophthalic anhydride, and the like. However, the essential drawback of conventional general-purpose bisphenol A epoxy resins is that their cured products are hard and have poor flexibility. It is difficult to use it for general paints, adhesives, etc.

In order to improve these drawbacks, polyamides obtained by condensation of polymerized fatty acids and polyamines and thiocol are well known as flexibility imparting agents and curing agents, and some flexible Polymer epoxy resins are also commercially available, but they are not fully satisfactory because they are expensive and, although they provide flexibility, they tend to exhibit a decrease in mechanical strength. The present inventors have invented a liquid epoxy resin with a main chain of polyale or polyester that provides flexibility and an epoxy skeleton at the end or inside the molecule.
It cures at room temperature with an amine curing agent such as polyamide, giving a hard and flexible cured product.

That is, in the present invention, a liquid polyether or polyester containing a carboxyl group having a molecular weight of 300 to 8,000 and an epoxy compound having at least two or more epoxy groups in the molecule are combined into one or more epoxy groups in one molecule of the epoxy compound. It is a liquid epoxy resin made by reacting at a rate that leaves epoxy groups.

The carboxyl group contained in the liquid polyether or polyester may be at the end of the molecule or inside the molecule; therefore, any carboxyl group that reacts with the epoxy group may be used. Typical epoxy resins of the present invention are represented by the following general formula, for example. General formula [wherein R1: polyether or polyester chain example (R is hydrogen, 150) methyl group or ethyl group, n=5~ (X, Y are each a divalent hydrocarbon group having 2 to 20 carbon atoms) or -()-(-CH2, etc. R2; Divalent aliphatic, cycloaliphatic, aromatic hydrocarbon group R,; Examples of organic groups containing one or more epoxy groups Polymers of the present invention Ether or polyester-epoxy resin is produced by reacting a long-chain polyether or polyester with active hydroxyl groups with a cyclic acid anhydride in the absence of a catalyst or in the presence of a catalyst, converting the hydroxyl groups of the long-chain molecules into carboxyl groups. Converted and then reacted with an epoxy compound having at least two or more epoxy groups in the molecule to give it an epoxy group, with a molecular weight of 500~
9000 liquid epoxy compound.

Molecular weight is 50@). Below 900 songs, the flexibility is poor, and above 900 songs, the workability is poor due to the high viscosity. The hydroxy polyether or polyester used to obtain the above-mentioned polyether or polyester-epoxy resin is mainly a long-chain molecule with a molecular weight of 3001. upper 80
It is in liquid form with a range of up to 0.00.

Such polyethers include ring-opened polymers of ethylene oxide, propylene oxide, tetrahydrofuran, and copolymers thereof. Examples of polyesters include condensation products obtained from polyhydric alcohols and polyhydric carboxylic acids. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, 1,3-butanediol, and lower polymers thereof, and examples of polyhydric carboxylic acids include aliphatic polycarboxylic acids such as succinic acid and adipic acid. Acids, aromatic polycarboxylic acids such as phthalic acid, etc. are included, but these condensation products need to be in liquid form. If carboxyl polyester is directly obtained during this polythousandester synthesis, the above-mentioned carboxylation reaction can be omitted. The cyclic acid anhydride used in the above carboxylation is as follows:
Examples include maleic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, and hexahydrophthalic anhydride. The above polyether or polyester
Epoxy compounds having at least two or more epoxy groups in the molecule used to obtain epoxy resins include aromatic epoxy resins such as general-purpose bisphenol A diglycidyl ether, saturated or unsaturated fatty acids, etc. Examples include alicyclic, alicyclic, or heterocyclic epoxy resins.

To obtain the above polyether or polyester-epoxy resin, the reaction ratio of carboxyl polyether or polyester with an epoxy compound having at least two or more epoxy groups in one molecule is as follows: The ratio of one molecule of the compound, that is, the ratio of epoxy compounds having at least two or more epoxy groups in one molecule, is required to leave at least one epoxy group, but if more epoxy compounds are added to the reaction system, It may exist.

In this case, unreacted epoxy resin will remain, and by changing the amount, the mechanical properties of the cured product can be adjusted. When the amount of the epoxy compound is less than the above-mentioned ratio, carboxyl groups remain and workability is deteriorated due to rapid thickening or gelation during curing with an amine compound or the like. Furthermore, if the amount of epoxy compound is too large, the desired flexibility will not be achieved. Therefore, the reaction ratio of the carboxyl polyether or polyester and the epoxy compound is suitably 2 to 20 moles, more preferably 2.1 to 10 moles, per 1 mole of the former. The reaction between the carboxyl polyether or polyester and the epoxy compound described above can be carried out without a catalyst or with a small amount of catalyst and without a solvent. Reactive solvents such as benzene, toluene, xylene, methyl isobutyl ketone, tetrahydrofuran, etc. can also be used.

As catalysts, tertiary amines such as pyridine and benzyldimethylamine, and acids such as para-toluic acid are effective, and the amount thereof is preferably 0.005 to 1.0% by weight based on the carboxyl polyether or polyester. It is 0.01 to 0.05 weight percent.

The reaction time and reaction temperature were 1 to 1 hour and 50 to 20 minutes, respectively.
0°C is appropriate, preferably 2 to 5 hours each.
The temperature is 100-150°C. Excessive temperature and time are undesirable because they may cause gelation or thickening of the reactants. The reaction can be easily monitored by infrared spectroscopy or by measuring oxidation.

The polyether or polyester epoxy resin of the present invention obtained as described above is a pale yellow, viscous liquid, and is cured at room temperature with an amine-based curing agent such as polyamine or polyamide.

The obtained cured product was pale yellow and transparent, had excellent adhesive strength and impact strength, and had excellent flexibility that could sufficiently withstand the 1800 bending test. This product is necessary for adhesives, paints, and other fields that require flexibility. Examples are shown below, but the present invention is not limited to these Examples.

Example 1 Polypropylene glycol 100 with an average molecular weight of 1000
32 g of phthalic anhydride in pyridine solvent at 80°C.
Allowed time to react.

After removing pyridine and unreacted phthalic anhydride under reduced pressure,
80 g of Epicote 828 (manufactured by Ciel Chemical, trade name) was added and stirred at 100° C. for 8 hours. What was obtained was a pale yellow viscous liquid with an epoxy equivalent of about 1000. The average molecular weight was about 2,000. In the above reaction, the reaction was confirmed by infrared absorption spectrum, but the absorption of carboxylic acidic hydroxyl group (2500-3500c711-1 plot) disappeared, and the slightly sharp absorption of hydroxyl group (3500C
111-ri appears.

1. of the above reaction products. R. The absorption is as follows. 35
0 泗-1, hydroxyl group 1730c71-1, ester carbonyl 830,10
40,1510,1580,1610cfR-1, rose-substituted phenyl 125 cm-1, phenyl ether 1100 cm-1, aliphatic ether 860,920 aft-1, epoxy group To 10 g of the obtained polyether-epoxy resin, add 400 m9 of triethylenetetramine was added, mixed uniformly, and then cured for n hours in the second (generation), to obtain a pale yellow, transparent, rubber-like cured product.

The mechanical properties of this material are tensile strength of 32k9/Cl! The maximum elongation at break was 190%. Furthermore, Kg of this polyether-epoxy resin and 82,810 g of Epicoat were mixed, 1.3 g of triethylenetetramine was added, and the mixture was uniformly mixed. When the mixture was cured at 20°C for 7 days, it turned pale yellow and transparent, and became tough. Moreover, a flexible cured product was obtained. The mechanical strength of this product is tensile strength 138 kg/C.
It is the maximum elongation ratio at il failure, and it withstood 18 bending tests. Example 2 Polypropylene glycol 100 with an average molecular weight of 1000
g and 32 g of phthalic anhydride were mixed and reacted at 200° C. for 10 hours.

After removing unreacted phthalic anhydride under reduced pressure, Epicoat 8
162 g of No. 28 (manufactured by Shell Chemical Co., Ltd., trade name) were added, and further 0.05 g of dimethylbenzylamine was added as a catalyst, and the mixture was reacted with 12C) for 2 hours. What was obtained was a pale yellow viscous liquid with an epoxy equivalent weight of 43 and an average molecular weight of 860.
It was hot. 10g of the obtained polyether-epoxy resin
triethylenetetramine 800]! 9 was added, mixed uniformly, and then cured at 20° C. for 7 days to obtain a pale yellow, transparent, tough, and flexible cured product.
The mechanical properties of this material were a tensile strength of 152k9/d1 and a maximum elongation at break of 80%, and it withstood the 1802 bending test. Example 3 Hydroxyl terminal polyester 1 with average molecular weight 1000
00g and 32g of phthalic anhydride were mixed and reacted at 49°C for 1m.

Claims (1)

[Scope of Claims] 1. A liquid polyether containing a carboxyl group with a molecular weight of 300 to 8,000 and an epoxy compound having at least two epoxy groups in the molecule are combined into at least one or more epoxy groups in one molecule of the epoxy compound. A liquid epoxy resin made by reacting at a rate that leaves epoxy groups. 2. The liquid epoxy resin according to claim 1, wherein the repeating unit of the polyether is substantially represented by the following formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R is an atom or group selected from hydrogen, methyl group, and ethyl group) 3. Claims 1 and 2 in which the compound containing an epoxy group is a bisphenol compound Liquid epoxy resin as described in section.