DE2138116A1 - EPOXY RESINS MODIFIED BY ACETIC ACETIC ESSENTIAL GROUPS AND METHOD FOR MANUFACTURING THEIR METHOD - Google Patents

Description

. Reichhold-Albert-Chemie AG, Hamburg 70, Iversstr. 27

Patent application ,.

Spoxydharse modified by acGtessi ^ ester groups and procedure zn their manufacture.

The invention relates to those modified by acetoacetic ester groups Epoxy resins and a process for their preparation. It is known to produce diketene with the help of various catalysts, e.g. tertiary amines or alkali salts of carboxylic acids, with Implement compounds that contain alcoholic OII groups. The corresponding acetoacetic esters are formed in the process. This implementation can also be carried out on polymers which contain alcoholic OH groups, such as polyvinyl alcohol.

It has now been found that new modified epoxy resins are obtained, when the free OH groups of the epoxy resins at least partially in the presence of a catalyst with diketene to form acetoacetic ester groups implemented. In general, the diketene is used in such a henge that the amount of diketene of those of the free hydroxyl groups is at most equivalent. The diketene reacts practically only with the alcoholic hydroxyl groups of Epoxy resin, so that acetoacetic esters arise at the same time Have epoxy groups.

Usually the reaction is conducted at elevated temperature, generally not more than 120 ⁰ C, preferably from Ho to 80 ° C, carried out, it will vary the temperature according to the epoxy resin. When using an epoxy resin in the liquid phase, sB respectively in the form of a solution. Dispersion, you can sometimes work at room temperature. Occasionally, however, it can also be desirable to use an excess of the diketene, based on the free OH groups, some of the epoxy groups also being unset. The course of the reaction according to the invention can be monitored by determining the epoxyda & gaha.

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It is advantageous to carry out the reaction in the presence of a catalyst which does not react with epoxy groups with oneself or with others present in the reaction mixture Groups catalyzed. Suitable catalysts are, for example, metal salts of mono- or polycarboxylic acids, for example lower ones Fatty acids, such as sodium potassium acetate or propionate, isononate or Calciura acetate or other alkaline earth and alkali salts. As a starting material A wide variety of customary epoxy resins are suitable, provided they have free hydroxyl groups, for example those based on polyhydric phenols such as diphenylpropane, diphenylplmethane, Triphenylolraethane and chlorohydrins, e.g. epichlorohydrin ', which may also - e.g. by alkyl-, alkoxy- halogen and / or nitro groups - may be substituted. They are also alipathic Suitable for epoxy compounds. It is also possible to use epoxy resins take as starting material which are partially esterified, for example with saturated or unsaturated fatty acids with 1 up to 22 carbon atoms, such as vegetable oils, e.g. linseed oils, soybean oil, Hioinus oil fatty acids, also with aromatic carboxylic acids, such as Benzoic acid and its derivatives, e.g. toluic acids. The reaction is usually carried out in the liquid phase, for example using a liquid or molten resin and / or one opposite the Diketet. inert solvent carried out. Suitable solvents are e.g. ketones, such as methyl ethyl ketone, liethyl isobutyl ketone.-fiyie- ^ c hexanone, ethylene glycol diethers, e.g. their diethyl ether, aromatic Hydrocarbons, chlorinated hydrocarbons.

The resins according to the invention usually have a considerably lower viscosity and - insofar as they are liquid resins - also a lower tendency to crystallize than the starting resins. The more OH groups are converted, the lower the viscosity. The lowering of the viscosity means that the resins are easy to process because no disruptive crystallization occurs. By exact dosage of the diketene - * ^ fe 1 llol-diketene to 2 hydroxyl groups - an at least partial esterification of the epoxy resins can also be brought about. This embodiment has the part that the number of functional groups in the molecule and thus the reactivity of the resin is increased.

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The number of acetoacetic ester groups per 1000 molecular weight units can in each case with the type of resin used and the proportion of the OH groups reacted with the diketene, based on the total OH groups, vary. In the case of low molecular weight resins, e.g. based on diphenylolpropane and epichlorohydrin, mxt molecular weights of approx 350 to 500 can, for example, a maximum of about 0.25 to about 0.9 Ketoester groups come to 1000 molecular weight units. In the case of resins on the same basis with a molecular weight of 900 to 1 ^ 00, a maximum of incorporate about 2 to 2.5 ketoester groups. Accordingly, the Resins, for example, at least 0.2, preferably 0.5, acetoacetic ester groups contained on 1000 molecular weight units. Below this range, in the case of the epoxy resins mentioned, the optimal properties are not obtained, epoxy resins are also applicable with lower proportions of acetoacetic ester groups within the scope of the invention.

In the "reaction equation (see formula sheet) is the erfinducgsgemäße Implementation of an epoxy resin (l) based on diphenylolpropane and epichlorohydrin represented with diketene, the free hydroxyl groups Quantitative to Acetate Gas Groups (3rd Compound III) have been implemented.

According to one embodiment of the invention, epoxy resins can be used with a low OH group content, e.g. with phenols and the increased number of OH groups can in turn be converted to acetoacetic ester groups with diketene.

The resins according to the invention can be prepared in a manner known per se cure like normal epoxy resins, e.g. with polyamines, aminoamides, acid anhydrides, polyols, epoxy resin-amine adducts and the like. In addition, it was found, for example, that their cold hardening with all hardeners containing the amino groups, so 'both with low molecular weight amines as well as with e.g. polyaminoamide resins, runs much faster than that of conventional epoxy resins.

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in agreement on

In addition, the acetoacetic ester groups can be specific Carry out reactions that can also contribute to networking or are interesting in themselves. For example, int the implementation of the acetoacetic ester group with suitable mixtures of Formaldehyde and amines possible. This increases the viscosity of the epoxy resins. In some cases this may be desirable when rapid solidification is desired. Another possibility is, for example, to convert the aceto-acetic acid groups with formaldehyde with the formation of reactive methylol groups. Since the resins according to the invention - even at relatively deep

W temperatures - harden quickly, they can be used not only for the production of varnishes and paints, but also for adhesives, forrate parts, impregnating agents, laminates, fci-ner in the building editor, for marking traffic routes or the like. Coatings from the products according to the invention are tack-free or firm more quickly than coatings on bases of the customary unmodified epoxy resins. In addition, the coatings show a light color, good gloss, hardness and elasticity. The coatings produced from the products according to the invention adhere extremely well to metals such as iron, copper, aluminum or their alloys.

The products according to the invention are used for the production of adhesives advantageous in a mixture with Polyaminoacidhara ^ n, especially for

L · Two-component adhesive used.

Examples:

1) In a 2 liter round-bottom flask equipped with a reflux condenser, thermometer and stirrer, 500 g of a solid epoxy resin with an epoxy number made from h, * f ~ diphenylolpropane and epichlorohydrin are added

Il

Dissolved 6.5o in 125 g of methyl ethyl ketone and admixed with 0.3 S powdery, anhydrous sodium acetate. The mixture is heated to 60 ° C. with constant stirring under a nitrogen atmosphere. The above-mentioned diketene is then added dropwise to a dropping funnel in such a way that the temperature of the reaction mixture does not exceed 70 to 75.degree. After completion of the diketene, the mixture is kept for another hour at 6O ⁰ C. Then allowed to cool to room temperature and

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removes the Na acetate by filtration. According to Abdestillleror. of the solvent under reduced pressure is obtained a reddish syrupy mass, the viscosity (measured at 60 C in a rotary ^e) over that of the starting resin of 75 ^ o cp cp has dropped to 6050th The approach is calculated so that practically all alcoholic OH groups of the epoxy resin used (on average 0.5 % equivalent OH per mole of epoxy resin) are esterified with acetoacetic acid. An epoxy number of 6.00 is calculated for the product from the epoxy number of the starting resin. It was found 6.14.

2) Under the reaction conditions mentioned in Example 1), 700 g of a diphenylolpropane and epichlorohydrin are prepared solid epoxy resin with an epoxy number of j5.34 in 300 g of methyl ethyl ketone dissolved and after the addition of 0.4 g of anhydrous Sodium acetate reacted with 66 g of diketene. After the solvent has been distilled off, a reddish, solid, glassy one is obtained Dimensions. The approach is calculated so that half of the alcoholic OH groups of the epoxy resin used (on average 2.15 equivalents of OH per mole of epoxy resin) esterified with acetoacetic acid are. Calculated from the epoxy number 3> J5 ^ of the starting resin the epoxy number for the product is 3.09. It was found 2.90.

3) Under the reaction conditions mentioned in Example 1), 7oo g of an iesten epoxy resin prepared from diphenylolpropane and epichlorohydrin with an epoxy number of 1.72 are dissolved in 500 g of methyl ethyl ketone and, after the addition of 1.0 g of anhydrous sodium acetate, reacted with 168 g of diketene. After the solvent has been distilled off, a reddish, solid, glassy mass is obtained. The approach is calculated so that practically all alcoholic OH groups of the epoxy resin used (on average 5.35 equivalents OH per mole of epoxy resin) are esterified with acetoacetic acid. The epoxy number of the starting resin is 1.72

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for the product an epoxy number of 1.39 · found 1.35.

4) loo g of a product which has been produced by reacting an epoxy resin made from diphenylolpropane and epoxy-chlorohydrin with an epoxy number of 3.34 with diketene under the conditions mentioned in Example 1) (2 moles of diketene to 1 mole of epoxy resin) and das.nach the reaction has an epoxide number of 2.79, are dissolved in 64 g of ethylene glycol monoethyl ether, and VJ g of dipropylenetriamine are added. This mixture gelled after 18 minutes at 20 ° C. Comparative experiment to example 4):

100 g of the epoxy resin not reacted with diketene and used as the starting product according to Example 4) are dissolved in 64 g of ethylene glycol monoethyl ether and mixed with 17 g of dipropylenetriamine. At 20 ^° C., this mixture only gelled after 4 hours.

5) loo g of a product that duroh implementation of an epoxy resin made from diphenylolpropane and epoxy resin with an epoxy number of 1.72 according to Example 1) has been made with diketene (5.3 moles of diketene to 1 mole of epoxy resin) and that after the reaction Has an epoxide number of 1.35, are dissolved in 64 g of ethylene glycol mono-ethyl ether and mixed with 15 g of dipropylenetriamine. This mixture has a pot life of 7 minutes.
Comparative experiment to Example 5) j

100 g of the epoxy resin used as starting substance in Example 5) are dissolved in 64 g of ethylene glycol monoethyl ether and treated with 7Z5 g of dipropylenetriamine. This mixture has a pot life of about 24 hours at 2O ⁰ C.

6) 100 g of the reaction product described in Example 5) are dissolved in 50 g of ethylene glycol ethyl ether and mixed with 50 g of a polyaminoamide of a dimeric fatty acid. This mixture has a pot life of 3 minutes.

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Comparative experiment to. Example 6);

loo g of that used as starting substance in Example 5) Epoxy resin are dissolved in 50 g of ethylene glycol monoether and mixed with 5 ° ß äes Polyarainöaraidharzes according to Example 6). This Gemisoh has a pot life of over 7 hours at 22 ° C.

7) 100 g of the reaction product described in Example 5) are dissolved in 45 g of methyl ethyl ketone and 50 g of toluene and with 12 g of dipropylenetriamine are added. The mixture is in looyu-Schlichtdicke applied to glass plates and baked at 100 ° C. for 20 minutes. A light brown colored, glossy one is obtained Film of good hardness (180 pendulum seconds, measured with the pendulum device according to König DIN 53 157) and very good elasticity, which is resistant to acetone and xylene.

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H C-CH-CH-2 \ /

0-

0-CH ₂ -CH-CH ₂ f OH

O-CH ₂ -CH-CH ₂ .

C = O

C = O CH ₅

(III)

- HO-CH - C-CH,

? = 0

(ID

CH.

η = 1 to 15

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Claims (1)

Pat e_n t_a__n 5 |> _r ü c_h e Epoxy resins modified by acetoacetic ester groups. 2. Epoxy resins according to claim 1, characterized in that they have at least 0.2 acetoacetic ester groups per 1000 molecular weight unit contain" 3. Ancestors for the production of Acetesaigestergruppen modified epoxy resins, characterized in that the free OH groups of the epoxy resins are at least partially in . Presence of a catalyst with diketene to form Aceteosigegutgruppen implemented. H. Process according to Claim 3 »characterized in that alkali salts of monocarboxylic acids, preferably sodium acetate, are used as the catalyst. 5. The method according to claim 3 or h _t, characterized in that partially esterified epoxy resins are used as starting materials. 6. The method according to claim 3 to 5%, characterized in that the amount of diketone is at most equivalent to that of the free hydroxyl groups. 7. Process according to Claims 3 to 6, characterized in that the reaction is carried out in the presence of a solvent that is inert to diketene. 209886/1093 AO 3. The method according to claim J5 to J, characterized in that the reaction is carried out in the presence of methyl ethyl ketone as solvent. 9 · Use of a resin according to claim 1 or 2 or a resin produced according to claims 3 to 3 for Manufacture of coatings or adhesives. Io. Embodiment according to Claim 9, characterized in that the resins are combined with polyamides for the production of adhesives. July 21, 1971
Dr.LO / ma 209886/1093