CS215309B1 - A method of producing polyester resin with increased electrical conductivity - Google Patents

Abstract

The invention relates to a method for producing a polyester resin with increased electrical conductivity by introducing a suitable electrically conductive group or atom directly into the polyester molecule. Such a group is, for example, calcium and/or magnesium salts of hydroxyethyl phthalate of the general formula where M is magnesium and/or calcium.

Description

The invention relates to a process for producing a polyester resin with increased electrical conductivity by introducing a suitable electrically conductive group or atom directly into the polyester molecule.

Expanding the application possibilities of polymeric substances also brings with it increasing problems related to the occurrence of static electricity. The problem of its solution, respectively. removal of polyesters is particularly demanding and has not been satisfactorily solved according to the prior art.

From the viewpoint of manufacturers' capabilities, antistatic treatment can be achieved either by the addition of various antistatic agents or directly by chemical modification of the polyester, i. j. by incorporating a suitable component into the polyester molecule during the polyesterification. Despite the fact that the solution of this problem is the subject of many patents, there is not yet known a transparent polyester with permanently antistatic properties and all known antistatic treatments are focused on the surface application of cutting, so-called. surface

HOCH ₂ CH ₂ OOC CO antistatic, or on the use of semiconductive and conductive fillers, most often metallic powders of silver, platinum, aluminum and other metals or oxides, respectively. combinations thereof, more or less surface-treated (Franc. Pat. 1 250 84Θ). Their disadvantage is, in addition to reduced or zero transparency, also a reduction in mechanical strength, brittleness, bulk deformation, a reduction in storage stability and, in some cases, a high cost.

These disadvantages are overcome by the process for producing polyester resins with increased electrical conductivity from di- to polyfunctional acids or their anhydrides by polyesterification, preferably catalytic, with diols to polyols, according to the invention, which is carried out such that saturated and / or unsaturated dicarboxylic acids and / or their anhydrides are polyesterified at 160 to 250 ° C with polyhydric alcohols in the presence of 0.01 to 1 moles of magnesium and / or calcium salts of hydroxyethyl phthalate of the general formula

COOCH ₂ CH ₂ OH wherein M is magnesium and / or calcium.

On the other hand, the reduction of the surface and lead resistance of transparent polyesters from flooding 10 ¹⁵ to 10 ¹⁶ ohms to 10 ¹⁰ to 10 ¹¹ ohms is achieved by introducing a suitable electrically conductive group or atom directly into the polyester molecule. Suitable groups are e.g. metal salts of monohydroxyethyl phthalate (HEF), respectively. (HEF) ₂ M ² +, boy ₂ ch ₂ ooc COOH

(HEF),

HOCH ₂ CH ₂ OOC coomooc Cooch ₂ CH ₂ OH (HEF) ₂ M ²⁺ wherein M is magnesium or calcium, having an ionic bond between the carboxyl group and the divalent metal atom and two hydroxyl groups, which are incorporated into the polyester chain.

The preparation of the polyester resins is carried out by polycondensation of the respective metal salts (HEF), respectively. (HEF) ₂ M ²⁺ · and glycols with saturated and / or unsaturated acid anhydrides at temperatures of 160 to 250 ° C. After reaching the desired acid number and cooling, the polyester can be diluted with styrene.

Evaluated prepared polyester resins in terms of their antistatic effect by contactless cumulaon method on electrification apparatus EP-02 at relative air humidity 45%, temperature 25 ° C and friction body retraction 0.04 N.mm ^-2 showed that the charge dispersion half-life, ie time , under which the friction charge is halved for a standard ethylene glycol maleate laminate type of polyester for 5.5 hours, pushing for 3 to 5 seconds with a magnesium-incorporated polyester. The surface and leakage resistance measured on a two-electrode instrument with stabilized DC voltage at 1000 V electrodes under the same conditions at a constant sample loading of 0.05 N.mm ^-2 between the electrodes was only 10 ¹⁰ ohms, unlike standard ethylene glycolmallate polyester with a surface and leakage resistance of 10 ¹⁵ ohms.

Example 1

3.8 mol of phthalic anhydride and 7.096 mol of diethylene glycol are charged to a polyesterification apparatus equipped with a condenser, stirrer and inert gas inlet and the mixture is heated at 190 ° C with stirring for 5 hours. 3.6 moles of maleic anhydride and 0.1044 moles of hydroxyethyl phthalate (HEF) ₂ Mg magnesium salt and 0.2 g of hydroquinone are added and the reaction mixture is heated under an inert nitrogen atmosphere at 180 ° C and 200 ° C for 3 hours to reach acid value 55 ± 5 mg KOH / g. At 100 ° C the prepared polyester is diluted with styrene.

Example 2

In a polyesterification apparatus as in Example 1, 2.2 moles of maleic anhydride, 2.00 moles of phthalic anhydride, 2.01 moles of ethylene glycol, 2.01 moles of propylene glycol, and 0.30 moles are heated under stirring at 180 DEG-190 DEG C. under an inert carbon dioxide atmosphere. 2 moles of hydroxyethyl phthalate magnesium salt (HEF) ₂ Mg for 8 to 9 hours to an acid number of 85 to 95 mg KOH / g. The reaction mixture was diluted with styrene after cooling.

Claims (1)

EXAMPLE 1 3.8 mol of phthalic anhydride and 7.096 mol of diethylene glycol are charged into a polyesterification apparatus equipped with a condenser, a stirrer and an inert gas feed, and the mixture is heated to 190 DEG C. for 5 hours. 0.8 mol of maleic anhydride and 0.1044 mol of hydroxyethyl phthalate (HEF) 2Mg magnesium salt and 0.2 g of hydroquinone are added and the reaction mixture is heated under inert nitrogen atmosphere at 180 ° C for 3 hours at 200 ° C until the acid number is reached. At 100 ° C, the prepared polyester is diluted with styrene Example 2 In a polyesterification apparatus as in Example 1, 2.2 moles of maleic anhydride are heated under stirring at 180 ° to 190 ° C and under an inert atmosphere. , 2.00 moles of phthalanhydride, 2.01 moles of ethylene glycol, 2.01 moles of propylene glycol and 0.2 moles of magnesium hydroxyethyl phthalate salt (HEF) 2Mg for 8 to 9 hours of acid value of 85 to 95 mg KOH / g. The reaction mixture is diluted with styrene after cooling. PREPARATION The process for producing polyester resin with increased electrical conductivity from di- to polyfunctional acids or their anhydrides by polyesterification, preferably catalytic, with diols to polyols, is characterized by wherein the unsaturated and / or unsaturated dicarboxylic acids and / or their anhydrides are polyesterified at 160 to 250 ° C with polyhydric alcohols in the presence of 0.01 to 1 mole of magnesium and / or calcium salts of hydroxyethyl phthalate of the formula HOCH 2 CH 2 OOC COOMOOC COOCH 2 CH 2 OH wherein M is magnesium and / or calcium.