CS261842B1 - Process for producing unsaturated polyester resins - Google Patents

Abstract

The method for producing unsaturated polyester resins based on unsaturated and saturated dicarboxylic acids or their anhydrides, further dihydric alcohols and olefinically unsaturated monomers and auxiliaries is carried out at a temperature of 100 to 250 °C, while saturated dicarboxylic acids or their anhydrides are substituted by 10 to 100% (30 to 70%) with a concentrate of a mixture of organic substances with an acid number of 400 to 800 mg KOH. g--1, containing at least two dicarboxylic acids, of which adipic acid makes up 35 to 80%. The said concentrate is isolated from an aqueous solution of a secondary oxygen-containing organic intermediate product of the oxidation of cyclohexane to cyclohexanone and cyclohexanol. The method is suitable for the production of unsaturated polyesters for lamination, coatings, especially for the production of cast seamless floors, plastic mortars and plastic concretes for construction.

Description

The method for producing unsaturated polyester resins based on unsaturated and saturated dicarboxylic acids or their anhydrides, further dihydric alcohols and olefinically unsaturated monomers and auxiliaries is carried out at a temperature of 100 to 250 ^° C, while saturated dicarboxylic acids or their anhydrides are substituted by 10 to 100% (30 to 70%) with a concentrate of a mixture of organic substances with an acid number of 400 to 800 mg KOH. g-- ¹ , containing at least two dicarboxylic acids, of which adipic acid makes up 35 to 80%. The said concentrate is isolated from an aqueous solution of a secondary oxygen-containing organic intermediate product of the oxidation of cyclohexane to cyclohexanone and cyclohexanol. The method is suitable for the production of unsaturated polyesters for lamination, coatings, especially for the production of cast seamless floors, plastic mortars and plastic concretes for construction.

6 1 8 4.2

The invention relates to a method for producing unsaturated polyester resins with an extended variability of starting materials, including the use of secondary oxygenated organic intermediates from the petrochemical process.

The production of unsaturated polyester resins, whether for laminating, for making cast seamless floors, plastic mortars, plastic concretes, prepregs, coatings, etc. has long been known [Mlezina J. et al.: Polyestery, ich výroba a zpračanom, pp. 286 to 395. Státní nakladatelství technické literatury, Praha [1964]; Czechoslovak author's certificates No. 170 937, 171 366, 171 360, 173 907, 206 574 and 232 307). Their preparation essentially consists of polyesterification and dissolution of polyester in a reactive monomer. The properties of polyester resins, of course, in addition to their production technology, can be influenced by many factors, most notably the type and amount of unsaturated and saturated dicarboxylic acids or their anhydrides, the type of diol to polyol, the type and amount of terminating alcohol or acid, as well as the type and amount of crosslinking monomer. Then there is the type and amount of inhibitor, the initiation or curing system, including the curing conditions, as well as the molecular weight of the polyester.

Unsaturated dicarboxylic acids, or rather their anhydrides, include primarily maleic anhydride. Fumaric acid, itaconic, citraconic, muconic, dihydromuconic, mesaconic and aconitic acids are also much less widespread. Of the saturated ones, phthalic anhydride, or isophthalic acid, terephthalic acid and adipic acid are mainly used. A ⁴ -tetrahydrophthalic acid, especially hexahydrophthalic acid are used even less frequently. 5-norbornene-2,3-dicarboxylic acid, or rather its anhydride and halogenated derivatives, pimelic acid, sebacic acid. However, the raw material and energy requirements of not only unsaturated but also saturated dicarboxylic acids and their anhydrides are a drawback, which also limits the development of the production of unsaturated polyester resins. Therefore, new raw materials are being sought as a replacement for the existing ones, which are technically and energetically more accessible, but which have more valuable properties, especially due to the new polyester resins. Thus, some car coatings resistant to carbon dioxide are made on the basis of polyesters made from isophthalic acid, neobutyl glycol and cross-linked with bexamethoxymethylmelamine, [Butter R., Boomgard RF: J. Oil Col. Chem. Assoc. 69, No. 12, 320 Γ1986] j. Particular attention is paid to the curing of unsaturated polyesters (Storey RF et al.: Polym. Preprints 27, No. 2, 167 [1986]), especially for powder compositions curable by radiation or thermochemistry, to the study of the possibilities and availability of raw materials [Kuzηρρονρ L, I. et al.: Lakokrasoč. mater, 1986, No. 5, 22), further to the composites of unsaturated polyester resins with aluminum (Mewaz GM: Polym. Composites 7, 176 [1986]) and the like. The above and other known methods of production and application of unsaturated polyester resins, however, require new components, which usually need to be solved by new production or expansion of existing, but scarce raw materials. Thus, the production method according to the present invention both uses the advantages of proven solutions and expands the raw material base for the production of unsaturated polyester resins in terms of quantity and assortment.

The method for producing unsaturated polyester resins based on at least one unsaturated and saturated dicarboxylic acid and/or their anhydride, at least one dihydric alcohol and an olefinically unsaturated monomer, optionally hydrocarbon and oxygenated organic comonomers and auxiliaries, at a temperature of 100 to 250 °C is carried out in such a way that the saturated dicarboxylic acids and/or their anhydrides are replaced by 10 to 100 %, preferably 40 to 75 %, of a concentrator of a mixture of organic substances with an acid number of 400 to 800 mg KOH. g- ¹ , containing at least two dicarboxylic acids, of which adipic acid constitutes 35 to 80 % by weight, whereby the concentrate is isolated from an aqueous solution of the secondary oxygenated organic intermediate from the oxidation of cyclohexane to cyclohexanone and cyclohexanol.

The advantage of the production method according to the present invention is the technical use of dicarboxylic acids and hydroxycarboxylic acids and other unidentified acidic organic substances present in the by-product of cyclohexane oxidation. In known types of unsaturated polyester resins, up to 70% by weight of saturated dicarboxylic acids or anhydrides can be replaced in their production without any loss of quality by the above-mentioned concentrate, the composition of which also allows the production of resins with new properties. By simple isolation from the intermediate by-product of the cyclohexane oxidation process, a concentrate is obtained not only with a relatively high content of a mixture of dicarboxylic acids, but also of other components used as modifying additives, practically free of olefinically unsaturated oxygenates and other compounds that would cause darkening and other undesirable effects on the quality of unsaturated polyester resins. Last but not least, the advantage is the possibility of carrying out the production method on a conventional esterification and polyesterification production equipment. The method also allows, due to the presence of hydroxy acids in the concentrate, to achieve, in addition to the flexibility of sources of saturated dicarboxylic acids, a reduction in the proportion, or a certain flexibility in the dosage of dihydric alcohols.

In carrying out the process of the present invention, at least a portion of the saturated dicarboxylic acids or their anhydrides are dried.

281842 is a concentrate of a mixture of organic substances with an acid number of 400 to 800 mg KOH. g ¹ , acids, adipic acid forming 35 to 80% by weight. In addition, it usually contains glutaric acid, succinic acid, monocarboxylic acids C1 to C6, 5-hydroxyvaleric acid, 6-hydroxycaproic acid and products of condensation reactions.

The concentrate of a mixture of organic substances resulting from the concentration and crystallization of an aqueous solution from the stripping of the reaction product of cyclohexane oxidation (oxidate), which in cyclohexanone and cyclohexanol production plants is usually subjected to hydrolysis to the stage of hydrolysis of a mixture of esters, mainly cyclohexyl esters of oxidation by-products (column DK 102), in order to increase the yields of mainly cyclohexanol, is therefore a secondary oxygen-containing organic intermediate. Depending on the conduct of the catalytic oxidation of cyclohexane process, the efficiency of the stripping with water, i.e. the composition of the aqueous solution (from column DK-10ÍJ), but also the degree of concentration by distillation of water, usually under reduced pressure, and separation of the crystalline portion by centrifugation, sedimentation or filtration, the concentrate of a mixture of organic substances has the following characteristics: water content — —· Z up to 15% by weight; acid number = 400 to 800 mg KOH . g ^_1 ; saponification number = 300 to 800 mg KOH/g - ¹ ; OH - content 3 to 8 % by weight; bromine number 0.1 to 3 g Br/100 g; adipic acid content = 35 to 80 % by weight; glutaric acid = 0.5 to 3.0 % by weight; succinic acid = 4 to 10 % by weight; propionic acid = 0.01 to 0.3 % by weight; butyric acid = 0.01 to 0.3 % by weight; valeric acid = 0.01 to 1 % by weight, with the remainder consisting of 5-hydroxyvaleric acid, 6-hydroxycaproic acid, condensation products such as esters, oligomers and other unidentified oxygenated organic compounds.

The dihydric alcohols most suitable for the production of unsaturated polyester resins are monoethylene glycol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol. Furthermore, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, polyethylene glycols, polypropylene glycols and 2,2-bis-(4-hydroxyphenyl)propanol.

Of the olefinically unsaturated monomers, styrene is the most suitable, followed by vinyltoluene, less suitable, but in combination with styrene or vinyltoluene, α-methylstyrene is also usable as a comonomer. Less widespread, but usable are methyl methacrylate, divinylbenzene, acrylamide, vinylcarbazole, N-vinylpyrrolidone, 2-vinylpyridine, acrylic acid and alkyl acrylates. A special group consists of allyl monomers, such as diallyl phthalate, diallyl isophthalate, diallyl fumarate, triallyl cyanurate, allylidene diacetate, diallyl terephthalate, diallyl-3,6-endomethylene-A ⁴ -tetrahydrophthalate and other known monomers.

The monomers and, as a rule, the unsaturated polyester resin are stabilized with conventional inhibitors of free radical reactions, such as hydroquinone, p-tert-butylcatechol, cumylphenols, phenothiazine, and the like.

Hydrocarbon comonomers, in addition to those already mentioned, include cyclopentadiene, dicyclopentadiene, oligomers of C2 to C6 alkenes and C3 to C6 dienes. The oxygenated comonomers of the above also include hydroxycarboxylic acids and monocarboxylic acids, keto acids and oligomers of hydroxycarboxylic acids and unsaturated carboxylic acids.

Auxiliary substances include paraffins, polymerization and copolymerization initiators, polymerization and copolymerization catalysts and activators, and curing accelerators for unsaturated polyester resins. Furthermore, fillers, pigments and dyes, inhibitors or resin stabilizers, antioxidants and anti-seize agents.

The process according to the invention is mainly carried out batchwise, but can also be carried out semi-continuously and continuously.

Further details on the implementation of the method according to the invention as well as some of its further advantages are apparent from the examples.

Example 1

Into an esterification flask with a volume of 1 dm ³ 120 g monopropylene glycol, 96 g monoethylene glycol are weighed while stirring and heating is started. At a temperature of 73 °C 147 g maleic anhydride, 203 g phthalic anhydride, 0.3 g paraffin are added and the air is removed from the esterification flask by blowing with medical nitrogen. The contents of the flask are heated to 180 °C, while esterification is taking place. The nitrogen blowing through ensures an inert atmosphere in the esterification and polyesterification environment, and also "removes ¹ vapor of reaction water. The temperature of the reaction mixture is gradually increased to 205 °C. When the acid number of 40 +2 mg KOH/g is reached, the polyesterification is terminated and the reaction mixture is cooled to a temperature of 175 °C. Then 0.12 g of hydroquinone is added to it as a stabilizer, or an inhibitor of polymerization and other radical reactions. Then the reaction mixture is further cooled to a temperature of 108 °C, 250 g of styrene containing 2.8 . 10 ^-3 wt. % p-tert.butylcatechol is added to it as a polymerization inhibitor and the temperature is reduced to 40 °C.

The total preparation time of this unsaturated polyester resin is 9 h (unsaturated polyester resin A).

Under otherwise similar conditions, a modified unsaturated polyester resin (unsaturated polyester resin B) is prepared, only instead of 203 g of phthalic anhydride, only 44.4 g of phthalic anhydride is used, but in addition 142.1 g of a concentrate of a mixture of mainly dicarboxylic, monocarboxylic and hydroxycarboxylic acids, or their esters, with an acid number = 611.5 mg KOH/g (can range from 400 to 800 mg KOH/g); saponification number = 648 mg KOH/g; OH — 6.1% by weight; water content = 6.5% by weight (can range from 2 to 15% by weight); adipic acid content = 50.2% by weight (range from 40 to 80%); glutaric acid — 1.7% by weight (range from 0.5 to 3%); succinic acid = 7.8% wt. (ranging from 4 to 10%); propionic acid == 0.1% wt.; butyric acid =- 0.1% wt.; valeric acid ~ 0.1% wt.; caproic acid = 0.2% wt., with the remainder being 5-hydroxyvaleric, 6-hydroxycaproic acids, their esters, oligomers and other unidentified oxygenated organic compounds.

The concentrate of a mixture of mainly dicarboxylic, inocarboxylic and hydroxycarboxylic acids, or their esters, is obtained from an aqueous solution of a mixture of organic substances formed by washing the reaction product (oxidate) from the catalytic oxidation of cyclohexane to cyclohexanone and cyclohexanol (aqueous solution from 1)K 109).

An aqueous solution of a mixture of organic substances with a water content of 04.6% by weight (can range from 30 to 90% by weight) has an acid number of 143.2 mg KOH/g (can range from 70 to 200 mg KOH/g); adipic acid content = 5.2% by weight (can range from 2 to 8%); glutaric acid = 1.1% by weight (0.3 to 2.0% by weight); succinic acid = 0.7% by weight (0.1 to 1.1% by weight) and 6-hydroxycaproic acid = 10.1% by weight (5 to 15% by weight). It also contains a mixture of carboxylic acids Cl to Cs, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, half-esters, esters and other unidentified organic substances.

An aqueous solution of a mixture of organic substances (from DK 109) is concentrated by distilling off part of the water under a pressure of 5.3 kPa and by cooling this concentrated solution to a temperature of 20 °C, a substantial part of the crystalline portion crystallizes from the solution, which is separated from the solution by filtration. The concentrate of the mixture of mainly dicarboxylic, monocarboxylic and hydroxycarboxylic acids, or their esters of the above composition, obtained in this way is used as a substitute for 5 to 80% by weight of phthalic anhydride and/or adipic acid in the production of unsaturated polyester resins.

A comparison of the technical parameters of unsaturated polyester resin A, prepared by a known procedure using the usual composition (recipe) of components with modified unsaturated polyester resin B with a 70% wt. replacement of phthalic anhydride, a concentrator of a mixture of mainly dicarboxylic, inocarboxylic and hydroxy acids, or their esters, is given in Table 1.

Table 1

Qualitative parameters

Unsaturated polyester resin A

Modified unsaturated polyester resin B

Kinematic viscosity at 20 °C, (mm ² . s- ¹ )

Density at 20 °C (kg . m“ ³ ]

Styrene content (% by weight).

Water absorption (% wt.)

Acid number (mg KOH . g- ¹ )

Stability at 80 °C

Curing characteristics according to ČSN 640 Gelatinization time (s)

Maximum exotherm (°C)

Curing time (s)

The results of the comparison in Table 1 show that in the preparation of unsaturated polyester resin, suitable for example for the production of base resins for the production of cast floors (unsaturated polyester resin A), it is possible to replace up to 70% by weight of phthalic anhydride without any loss of quality with a concentrate of mainly a mixture of dicarboxylic, inocarboxylic and hydroxycarboxylic acids, or their esters, isolated from an aqueous solution of a mixture of organic substances as a by-product in the production of a mixture of cyclohexanol and cyclohexanone by the oxidation of cyclohexane.

170.0 168.6 1166.4 1110.2 28.2 34.6 1.7 0.6 21.0 22.0 >45 >40 □ . 451.6 349.2 134.8 130.7 667.6 624.4 Example 2

The working procedure is similar to that in Example 1, only the composition of the components for the preparation of unsaturated polyester resin C is different. 237.5 g of diethylene glycol are weighed into a 1 dm ³ flask, then 90.7 g of maleic anhydride and 137.2 g of phthalic anhydride. The temperature of the reaction mixture is increased to 210 °C with stirring and constant nitrogen bubbling, at which it is maintained until the acid number drops to 32 to 36 mg KOH per gram. Then, after cooling to 175 °C, 0.06 g of hydroquinone and 0.09 g of paraffin are added.

When the reaction mixture is cooled to a temperature of 75 to 100 °C, 139.7 g of styrene prestabilized with 3.10 ^-3 wt. % p-tert-butylcatechol are added. After cooling to 40 °C, an unsaturated polyester resin (unsaturated polyester resin C) is thus prepared for applications.

In another experiment under similar conditions, only by replacing 50% of the phthalic anhydride with a concentrate of mainly dicarboxylic, monocarboxylic and hydroxycarboxylic acids, or their esters, specified in Example 1, unsaturated polyester resin D is produced.

A comparison of the properties of unsaturated polyester resins C and D is given in Table 2.

Indicator

Table 2

Unsaturated polyester Unsaturated polyester resin C resin D (modified)

Viscosity at 20 °C (mPa.s) 1112 1114

Density at 20 °C (kg . m--') 1,089 1,091

Acid number (mg KOH.g ^-1 ) 26 25

Shrinkage volume (%) 6.5 6.5

Content of non-volatile substances (°/o wt.) 77.5 78.1

Example 3

72.8 g of monoethylene glycol, 90 g of propylene glycol, 107.1 g of maleic anhydride and 161.7 g of phthalic anhydride are weighed into the esterification flask specified in example 1.

The temperature of the reaction mixture is heated to 110 °C with stirring and continuous nitrogen bubbling. It is maintained at this temperature for 30 min. Then the temperature is gradually increased to a temperature of 205 to 210 °C for 6 h. It is maintained at this temperature until the acid number drops to 48 to 52 mg KOH. g- ¹ .

The reaction mixture is then cooled to 175 ^° C, 0.068 g of hydroquinone and 0.23 g of paraffin are added. The mixture is further cooled to 100-105°C and 217.5 g of pre-crystallized styrene are added. After the styrene has dissolved, the finished unsaturated polyester resin (E) is used as a laminating unsaturated polyester resin or for formulation with another resin, such as C or JI from Example 2, to produce cast boškár floors.

In the next experiment, a similar procedure is followed, only instead of 131.7 g of phthalic anhydride, only 70 g and 91 g of the concentrate of the mixture of mainly dicarboxylic, monocarboxylic and hydroxycarboxylic acids, or their esters, specified in Example 1, are weighed. A modified unsaturated polyester resin (F) is obtained. A comparison of the properties of both unsaturated polyester resins is given in Table 3.

Table 1' and 3

Indicator

Unsaturated polyester resin E

Unsaturated polyester resin F

Viscosity at 20 °C (mPa.s)

Acid number (mg KOH . g ^_1 )

Non-volatile matter content (% lnnot.)

Miscibility with styrene (% by weight)

Curing characteristics according to ČSN 640 345 Gelation time (s)

Maximum exotherm (°C)

Curing time (s)

Claims (3)

261842 10 add 0.06 g hydroquinone and 0.09 g paraffin. When the reaction mixture was cooled to 75-100 ° C, 139.7 g of styrene-stabilized 3 was added. 10-3 wt. p-tert-butylcatechol. After cooling to 40 ° C, the unsaturated polyester resin (unsaturated polyester resin C) is thus prepared. In a further experiment under similar conditions, only the replacement of 50% phthalic anhydride with a concentrate mainly of dicarboxylic, monocarboxylic and hydroxycarboxylic acids, respectively. unsaturated polyester resin D is produced in their esters specified in Example 1. Comparison of the unsaturated polyester resin properties C and D is shown in the table 2. Indicator Table 2 Unsaturated polyester Unsaturated polyester resin C resin D (modified) Viscosity at 20 ° C (mPa.s) 1112 1114 Density at 20 ° C (kg. M -: ') 1,089 1,091 Acid number (mg KOH g-1) 26 25 Shrinkage volume (%) 0,5 6,5 Non-volatile content (° / w) 77,5 78,1 Example 3 We weigh 72.8 g of monoethylene glycol, 90 g of propylene glycol, 107.1 g of maleic anhydride and 161.7 g of phthalic anhydride in a cocification flask which has been quenched in Example 1. The temperature of the reaction mixture was heated to 110 ° C with stirring under nitrogen. It is maintained at this temperature for 30 min. Thereafter, the temperature is gradually increased to a temperature of 205 to 210 ° C for 6 h. The temperature is maintained until the acid number drops to 48 to 52 mg KOH. g-1. Thereafter, the reaction mixture is cooled to 175 ° C, 0.068 g of hydroquinone and 0.23 g of paraffin are added. The mixture is further cooled to 100 to 105 ° C and 217.5 g of pre-stabilized styrene is added. After dissolution of the styrene, the finished unsaturated polyester resin (E) is used as a laminating unsaturated polyester resin or on a formulation with another resin such as C or J1 from Example 2 for the production of castless floors. In a further experiment, a similar procedure is followed, except that instead of 131.7 g of phthalic anhydride, 70 g of 91 g of dicarboxylic acid concentrate concentrate are added thereto. of the monocarboxylic and hydroxycarboxylic acids or esters specified in Example 1. A modified unsaturated polyester resin (F) is obtained. We compare the properties of the unsaturated polyester resins in Table 3. T abu 1 'ka 3 Indicator Unsaturated Polyester Resin E Unsaturated Polyester Resin F Viscosity at 20 ° C (mPa.) Acid Number (mg KOH. G_1) Nonvolatile Content (% w / w) Miscibility with styrene (° / w) Curing characteristic according to ČSN 640 345Gelatinization time (s) Maximum exotherm (° C) Curing time (s) 573 601 26,5 26,9 62,3 63,5 93 98 243 ARTICLE A method for producing unsaturated polyester resins by reacting at least one unsaturated and one saturated dicarboxylic acid and / or an anhydride thereof, at least one divalent alcohol and an olefinically unsaturated monomer, respectively. hydrocarbon and oxygenated organic comonomers and auxiliaries, at a temperature of 100 to 250 ° C, characterized in that the saturated di-carboxylic acids and / or their anhydrides are from 10 to 100%, preferably from 40 to 75% replacing organic compound concentrators with an acidity value of 400 to 800 mgKOH / g-1, containing at least two dicarboxylic acids, of which adipic acid forms 35 to 80% by weight, the concentrate is recovered from the aqueous a solution of the secondary oxygen organic intermediate from the oxidation of cyclohexane to cyclohexanone and cyclohexanol.