CS243909B1 - Modified polyester bitumens production method - Google Patents

Abstract

For the production of modified polyester resins performed at 80 to 300 ° C and generally with the participation of esterification or polyesterification catalysts excluding traditional raw materials (mono- to tetracarboxylic acids or their anhydrides, diols to polyols, optionally esters, etc.) as the component mainly uses the distillation residue from the production of terephthalic acid or dimethyl terephthalate. This, except small quantities terephthalic acid, respectively. DMT trimellitic acid, respectively. its methyl esters, contains aromatic aldehyde acids oxygenated organic condensation oxidation catalyst products and residues. Application, except for positive syinergism the multi-component blend makes it deliberate variability of modified polyester properties resins, especially alkyd resins use as a component of a wide range of paint coatings application possibilities.

Description

2

In addition to the traditional raw materials (mono- to tetracarboxylic acids or their anhydrides, diols to polyols or esters, etc.), the distillation residue from production of terephthalic acid or dimethyl terephthalate. This, in addition to small amounts of terephthalic acid, resp. dimethyl terephthalate, trimellitic acid, respectively. its methyl esters, contains aromatic aldehyde acids, oxygenated organic condensation products and oxidation catalyst residues.

The application, in addition to the positive synergism of the multi-component mixture, allows the deliberate variability of the properties of the modified polyester resins, especially alkyd resins, to be used as a component of coating substances with wide application possibilities.

243809

The invention relates to the production of modified polyester resins, in particular alkyd resins, using, in addition to the customary components, by-products from some oxidative petrochemical processes.

Modified polyester resins, such as e.g. alkyds are well known and are widely produced on the basis of polyhydric alcohols and polyhydric acids, modified most often with fatty acids of natural drying and semi-drying oils or with synthetic monocarboxylic acids. Of polycarboxylic acids, respectively. their anhydrides are most often used for the production of alkyds phthalic anhydride. The application of terephthalic acid or its dimethyl esters for the preparation of alkyd resins is also known [Wagner W., Sarx H. F .: Lackkunstharze, p. 86-127, Hansen, Munchen (1971); Mleziva J. et al .: Polyesters, their production and processing. 2nd Edition, e, p. 256. SNTL Praha (1978)] Similar use of trimellitic acid or its hnihydride in co-combination with phthalic anhydride for the preparation of alkyds is also known [Gofdberg Μ. (1972)].

Said raw materials bring about an improvement in some properties of alkyds such as drying, water resistance and elevated temperature. On the other hand, in the preparation of alkyds from terephthalic acid, a higher esterification temperature is required than with phthalic anhydride, due to its higher melting point and lower solubility in the reaction mixture. Also, the change in viscosity during the preparation of the alkyd is different when using terephthalic acid than the phthalic anhydride alkyds. Initially, the increase in the viscosity of the terephthalic alkyd porn, however, is ultimately faster than that of the phthalic anhydride alkyd. The terephthalic acid alkyds can be prepared by melt or solvent processes. However, the development of the production of alkyd and other modified polyester resins limits the lack of starting materials. This problem is partly solved by the use of by-products, more or less the oligomers of the polyesterification of dimethyl terephthalate with ethylene glycol, both to unsaturated polyesters and to the alkyds Snezko et al. The fact that distillation residues from the production of dimethyl terephthalate or terephthalic acid can be evaluated by p-xylene oxidation processes can be used to produce polyester polyols suitable for preparing polyurethane foams having good performance properties. This invention solves another variant of the recovery of these distillation residues by the use of by-products such as distillation residues from the production of both terephthalic acid and dimethyl terephthalate.

According to the invention, a process for the production of modified polyester resins, preferably alkyd resins, by reacting monocarboxylic to tetracarboxylic acids and / or their anhydrides, diolives to polyols, optionally esters, low molecular weight polyesters, aldehyde acids and lactones, generally together, gives esterification and / / or a polyesterification catalyst or catalysts, at a temperature of 80 to 300 ° C, wherein low molecular condensation products, such as water and methanol, are removed from the reaction medium, preferably with the aid of a solvent, by carrying out one component of the reaction mixture to produce modified polyester resin or resins. is a distillation residue from the production of terephthalic acid from p-xylene by catalyzed oxidation, with an acid number of 250 to 700 mg KOH / g, preferably 450 to 550 mg KOH / g, a saponification number of 2 to 100 mg KOH / g, preferably 5 to 25 mg KOH / g and / or the distillation residue from the production of dimethyl ether Ephthalate with an acid number of 2 to 150 mg KOH / g, preferably 20 to 80 mg KOH / g and a saponification number of 300 to 650 mg KOH / g, preferably 440 to 520 mg KOH / g.

The distillation residues from the production of terephthalic acid or dimethyl terephthalate are dark, pitch, semisolid to solid substances which, in addition to a minor amount of terephthalic acid or dimethyl terephthalate, generally contain trimethyl ester of trimellitic acid, aromatic aldehyde acid and a wide variety of condensation products of aromatic dicarboxylic acids. tricarboxylic acids, their methyl esters, and other oxygen-containing aromatic compounds, usually additionally contain admixtures of metals such as cobalt, manganese, chromium, nickel, iron, molybdenum, and possibly also calcium, magnesium, silicon, barium, media, etc. in the form of salts.

An advantage of the process according to the invention is the technical extension of the raw material base for the production of modified polyester resins, in particular for the production of alkyd resins, also useful as binders for paints. A further advantage is the simultaneous utilization of transition metal impurities in distillation residues, mainly derived from the catalytic system of oxidation of p-xylene, in particular cobalt and maugan, as catalysts for curing the resins produced. This makes it possible to at least reduce the need for siccatives. Last but not least, the method makes it possible to exploit the positive synergism of the multi-polar distillation residues from the production of either dimethyl terephthalate or terephthalic acid, especially in the production of alkyd resins. Resins prepared in this way achieve good lacquer-technological properties such as: fast drying, high hardness, elasticity, stability to climatic conditions, higher resistance to alkali solutions and elevated temperature.

According to the present invention, the distillate residue from the production of dimethyl terephthalate and / or terephthalic acid seline is used as the acid (s) or in combination with other mono-carboxylic to tetracarboxylic organic acids, respectively. their anhydrides. These are mainly isophthalic acid, maleic acid and maleic anhydride, fumaric, succinic, adipic, azelaic, sebacic, itaconic, o-phthalic, terephthalic, diphenyl, trimellitic, further Diels-Alder products of maleic acid and mainly maleic anhydride conjugate. (hexahydrophthalic anhydride, endomethylene tetrahydrophthalic anhydride), trimellitic anhydride, pyromellitic anhydride, but most often phthalic anhydride.

The distillation residue or distillation residues from the production of dimethyl terephthalate or terephthalic acid can be used in the flood or after. modification, e.g. after discolouration or at least partial regeneration of metals. These distillation residues are decolourised by treatment with hydrogen peroxide, chlorine, alkali metal hypochlorites, phosphoric acid or adsorbents. Metals are removed by ion exchange, distillation, steam distillation and extraction with suitable reagents.

The sources of the aliphatic monocarboxylic olefinically unsaturated and saturated long carbon backbone acids used to produce the modified polyester resin of the present invention are synthetic but mainly natural drying and polyhydric oils, optionally treated, in particular rope, soy, dehydrated castor and castor oils. sunflower and more.

However, tall oil fatty acids as well as synthetic fatty acids such as: peliargonic, isococtanoic, isononanoic, lauric and the like are also suitable. and mixtures thereof. Some of these acids can be replaced with natural resins containing carboxyl groups, such as e.g. rosin.

Diols also include polyols for the production of polyester. The resins according to the invention can use all known diols to polyols used for the production of classical alkyds, in particular glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol, trimethylolethane, diethylene glycol, neopentyl glycol, propylene glycol, dipropylene glycol, butanediols and others.

The alkyds of this invention are preferably prepared under a protective atmosphere of an inert gas such as nitrogen or carbon dioxide. If free fatty acids or castor oil are used to modify the polyester, the terephthalate-based alkyd may be prepared in a one-step process, i. no. by co-heating the residues, possibly polycarboxylic acids with polyols and fatty acids, with castor oil, the temperature gradually increases to a maximum of 250 ° C. The process can be further modified by adding the fatty acids sequentially to the reaction mixture. In the preparation of the alkyds of the invention in a two-step process, in the first stage, partial esters are obtained by the esterification of oils with polyols at a temperature of not more than 260 ° C, preferably in the presence of a catalyst ®, e.g. lead oxide, oxides of molybdenum, manganese, antimony, germation, calcium, titanium tetrabutoxide, lithium hydroxide and the like. The partial esters are then reacted in the second phase with distilled terephthalate residues and other polycarboxylic acids. In this case, it can also be carried out by first carrying out (re) esterification with terephthalic residues to a low acid number, before adding the polyvinyl carboxylic acids or their anhydrides, and the polyesterification is completed. Preferably, the polyesterification is carried out in the presence of 2 to 10% of a co-solvent with a suitable boiling point, the miscibility of which is limited with science.

With this circulating solvent, the esterification water is removed from the reaction mixture to speed up the preparation. Suitable solvents of this type are, for example: methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, ethylamyl ketone, diisobutyl ketone, xylene, cumene and others. After addition of the polycarboxylic acid and the co-solvent, the temperature is gradually increased at a rate of 5 to 30 ° C per hour up to a max. 270 degrees Celsius. The progress of the polyesterification is monitored, in particular, by the acid value and the viscosity of the reaction mixture after its dissolution to a solution of the appropriate dry matter in a suitable solvent, for example, white spirit or xylene. Further details of the preparation of the alkyds of this invention as well as other advantages are apparent from the examples below.

Example 1

293.0 g of linseed oil and 74.5 g of pentaerythritol are heated to 100 degrees Celsius with stirring under a nitrogen atmosphere. After the addition of 0.03 g of lead oxide, heating is continued so that the temperature rises evenly and reaches a temperature of 240 DEG C. after 1.5 h. The reaction mixture is maintained at this temperature for 1 h until stirring with methanol (after centrifugation of unreacted pentaerythritol). to 3.5 cm @ ^{3 of} methanol per g of reaction mixture After cooling to 190 DEG C., 88.2 g of terephthalate residues are added and an azeotropic adapter with a reflux condenser is fitted.

Used terephthalate residues, resp. the distillation residue from dimethyl terephthalate production has an acid number of 24 mg KOH / g and a saponification number of 462 mg KOH / g after deducting the acid number. Of the inorganic elements, the residues contain, in particular, cobalt and manganese in the form of salts in amounts of 0.28, respectively. 0.05 wt. The melting point of the residues is 55 ° C, the dimethyl terephthalate content 8.6% by weight. and a trimellitic acid trimethyl ester content of 3.2 wt.

The temperature is gradually raised and maintained in the range of 235 to 240 ° C until the amount of liquid distilled into the azeotropic trap well ceases. A total of 16.5 cm ^{3 of} distillate containing mainly methanol and water distills off. The reaction mixture is cooled to 180 ° C, 88.2 g of phthalic anhydride are added and the temperature is maintained for 0.5 h. The azeotrope is then filled with xylene after the overflow and an additional 30 cm ^{3 of} xylene are added. Over a period of 1.5 h, the temperature is raised uniformly up to 237 ° C and s, maintaining a temperature of 232 to 235 degrees Celsius, distilling a further 25 cm ^{3 of the} aqueous phase into the azeotropic well and reducing the acid number of the reaction mixture to 9, 7 mg KOH / g.

After draining the azeotropic receiver and distilling the xylene, the temperature is gradually allowed to drop to 210 ° C, and the viscosity of the resin solution is monitored at regular intervals of 40% by weight. in white spirit at 20 ° C. After reaching a viscosity of this solution above 140 mPa. The batch is cooled and at 90 ° C the resin is diluted with white spirit. 52.4% wt. solids. The viscosity of this solution is 2115 mPa. with. A resin solution having a concentration of 40% by weight. in mineral spirit has a viscosity of 148 mPa.s at 20 ° C. s, spout consistency 36 s. The solid resin has an acid value of 6.9 mg KOH / g, saponification value 310 mg KOH / g, an OH number of 70.2 mg KOH / g (uncorrected for no. The acid] and an iodine number of 98.3 g I _2/100 Stage A dried sieve film dries in 1 h 45 min, Stage B5 dries in 2 days After 3 days, unpigmented coatings of 61 μω on glass have a pendulum hardness of 9%, after 30 days 38%.

For the drying tests, the resin solution is siccated with cobalt and lead naphthenates in an amount of 0.03% by weight. Co and 0.3 wt.%, Pb per alkyd dry matter. Drying is tested on stage CSN 67 3053, pendulum hardness according to CSN 67 3076 and consistency of a 4 mm nozzle spout according to CSN 67 3013. non-pigmented coatings, also given in other examples.

Example 2

291.3 g of tall oil (acid value - = 192.6 mg KOH / g, a saponification value of ~ - 197.1 mg KOH / g Iodine value = 138.8 g I _2/100 g, a resin acid = 11, 3% by weight; unsaponifiable = 0.9% by weight), 206.8 g of distillation residues from dimethyl terephthalate production (acid number = 63.7 milligrams KOH / g; saponification number = 481 milligrams KOH / g; p-methyltoluylate - 0.2% by weight, ash content = 0.3% by weight, cobalt = 0.1% by weight, manganese - 0.02% by weight and 0.8% by weight, dimethyl terephthalate = 6.2 trimethyl ester of trimellitic acid = 3% by weight, melting point 65-67 ° C and viscosity 142 mPa · s at 75 ° C), 137.9 g of phthalic anhydride, 131.7 g of 99% pure glycerol and 11.2 g of diethylene glycol was stirred, under nitrogen, heated to 150 DEG C. and the temperature is further increased sion rate of 10 to 20 ^DEG C / b to 225-230 ° C. The reaction mixture is kept under stirring at this temperature for several hours while distilling off a total of 55 cm ^{3 of a} mixture of water and methanol. The resin is cooled and diluted with xylene to a 63.6% by weight solution having a viscosity of 2,340 mPa.s. s at 20 degrees Celsius. Resin solution in xylene containing 50% (w / w). has a viscosity at 20 ° C of 298 mPa. the consistency of the spout cup 56 sec.

The solid resin has an acid number of 10.8 mg KOH / g; saponification number 356 mg KOH / g; iodine number 40.1 g I100 g and OH - number 72.5 mg KOH / g.

Example 3

195.0 g of soybean oil, 98.0 g of dehydrated castor oil, 43.0 of pentaerythritol are re-esterified in the presence of 0.03 g of PbO in a similar manner to Example 1, whereby the miscibility reaches 1.5 cm ^{3 of} methanol / g reaction mixture. After cooling to 190 ° C, 79.8 g of isophthalic acid, 20.0 g of the terephthalate residues specified in Example 2 and 0.4 g of zinc vinegar, as esterification catalyst, are added. The temperature is gradually raised at a rate of about 10 degrees Celsius per hour up to 230 ° C and the reaction water is distilled off and azeotropic, using 30 cm ^{3 of} methyl isobutyl ketone as solvent and distilling off 15 cm ^{3 of} water. Upon completion of esterification and cooling, the resin was diluted with white spirit to a 59.2 wt.% Solution having a viscosity of 1130 mPa · s. at 20 ° C. The viscosity of the resin solution in white spirit at a concentration of 50% by weight. at 20 ^DEG C. it is 296 mPa. . with consistency of spout: cup 61 s. The solid resin has an acid number of 10.5 mg KOH / / g; saponification number 288 mg KOH / g; OH number of 16.6 mg KOH / g and an iodine number of 86.6 g I _2/100 g.

Non-pigmented coating films of the same siccativation and similar depth as in Example 1 dry to Stage A in 2 h 20 min, to Stage B2 in 1 day. The pendulum hardness after 3 days is 7 ° / o.

Example 4

586.0 g of rope oil and 158.8 g of pentaerythritol are transesterified in an inertia of 0.06 grams of PbO at a maximum temperature of 240 ° C in a similar manner to that described in Example 1. The preparation is continued as in Example 1, except that For the esterification, the 311.1 terephthalate residues characterized in Example 1, 133.3 g of phthalic anhydride and 60 cm @ ^{3 of} xylene were used to distill off the esterification water. The reaction with the terephthalate residues is carried out at a temperature of 240 degrees Celsius, releasing 30 cm ³ of the methanol-water mixture.

Upon esterification with phthalic anhydride, it distilled off an additional 25 cm ^{3 of the} aqueous phase. The resin is then diluted with white spirit to 52.2 wt. solids. This solution has a viscosity of 2090 mPa.s at 20 ° C. the resin solution having a concentration of 40 wt. has a viscosity of 161 mPa at 20 ° C. with a consistency of 40 s. The acid number of the resin obtained is 4.7 mg KOH / g; saponification number 316 mg KOH / g; OH number 64.6 mg KOH / g and iodine number 91.3 g I ₂ / / 100 g resin. A paint film of 58 mm thickness, sicated as in Example 1, dries to Stage A in 45 min., To Stage B5 in 2 days. The pendulum hardness of these coatings after three days is 13% and after; 20 days 43%.

Example 5

293.0 g of soybean oil are re-esterified with 53.0 g of pentaerythritol and 13.2 g of trimethylolpropane with a catalytic effect of 0.03 g of PbO similar to Example 1, achieving a miscibility of 2.5 cm ^{3 of} methanol / g of reaction mixture.

After addition of 98.5 g of phthalic anhydride and 42.2 g of the distillation residue from the production of dimethyl terephthalate specified in Example 2, the es10 is thereafter treated in a solvent manner, gradually increasing to 235 ° C. 11 cm ^{3 of} water distilled off azeotropically. 30 cm @ ^{3 of} xylene are used as solvents. After completion of the reaction and cooling, the resin was diluted with white spirit to 61.1 wt. solids. This solution has a viscosity of 2046 mPa at 20 ° C. with. The viscosity of a 50% by weight resin solution. in white spirit at 20 ° C is 268 mPa. the consistency of the discharge cup 52 s. Coating films, sicatified as in Example 1 and approximately the same depth, dry to stage A in 3 h 30 min and have a pendulum hardness above 7 ° / o after 3 days.

Example 6

The procedure is similar to that of Example 5, except that 42 g of the distillation residue from dimethyl terephthalate production uses 42 g of the distillation residue from the production of terephthalic acid having an acid number of 520 mg KOH / g and a saponification number of 10.5 mg KOH / g. The viscosity of the 50 resin solution of the prepared resin. wt. is 271 mPa.s at 20 ° C. s and spout consistency 53 s. The coating films, sicatified as in Example 1 and approximately the same depth, dry to stage A in 3 h 25 min and have a pendulum hardness above 7 ° / o after 3 days.

SUBJECT

Claims (1)

Process for producing modified polyester resins, preferably alkyd resins, by reacting monocarboxylic to tetracarboxylic acids and / or their anhydrides, diols to polyols, optionally esters, low molecular weight polyesters, aldehyde acids and lactones, usually in conjunction with esterification and / or polyesterification catalyst or catalysts, 80 to 300 ° C, wherein low molecular condensation products, such as water and methanol, are removed from the reaction medium, preferably with the aid of a solvent, characterized in that a distillation residue from the production is used as one component of the reaction mixture to produce modified polyester resin or resins. oxidation catalyzed terephthalic acid from p-xylene with an acid number of 250 to 700 mg KOH / g, preferably 450 to 550 mg KOH / g, a saponification number of 2 to 100 mg KOH / g, preferably 5 to 25 mg KOH / / g / or distillation residue from the production of dimethyl terephthalate with heading No an acid refraction of 2 to 150 mg KOH / g, preferably 20 to 80 mg KOH / g and a saponification number of 300 to 650 mg KOH / g, preferably 440 to 520 mg KOH / g.