SU960198A1 - Homogeneous method of producing polymino acids - Google Patents

Description

(5) HOMOGENEOUS METHOD FOR OBTAINING POLYAMID ACIDS

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The invention relates to methods for producing polyamide acids by polycondensation of aromatic tetracarboxylic acid dianhydrides and aromatic diamines in an environment of polar solvents used to produce heat-resistant polyimide films, enamelling wire, as electrical insulating varnishes, and the like. in the electrical, radio and ational industry.

By entering the source components in. polyamic acid production processes can be divided into heterogeneous and homogeneous. J5

With heterogeneous polycondensation, at least one of the reagents is either reacted in solid form, suspended in an OH heterogeneous polycondensation, from a 20 point of view, the design of a continuous polycondensation process presents known difficulties due to the complexity and unreliability of dosing of dusty and electrifying monomers ), insufficient homogenization of the polyamic acid solutions obtained, hindered heat removal during the reaction, etc. The use of the suspension also cannot provide reliable dosing.

In the case of homogeneous polycondensation, both monomers are completely soluble in the solvent or solvent mixture used, and the polyamic acid obtained is either precipitated during the reaction of l or soluble in the same medium 2. In the latter case, there is a history of homogeneous polycondensation.

Homogenous polycondensation with polymer precipitation also has disadvantages. Polyamide acid aeration precipitates unreacted functional groups from the reaction sphere, resulting in a polymer with a low molecular weight; polyamic acid cannot be directly used as a varnish to produce films. This operation is preceded by filtering, rinsing, drying, dissolving in a polar solvent to produce lacquer, which causes a significant decrease in molecular weight during these operations and complicates the process, Only true homogeneous). polycondensation allows a continuous process for the production of polyamic acids, devoid of these drawbacks. In this case, accurate and reliable dosing of the initial monomers is ensured and their equilibrium ratio is maintained. . Closest to the invention is a method according to which poly amic acid is obtained by homogeneous poly condensation of tetracarboxylic acid dianhydrides and aromatic diamides in amide solvents. However, as studies have shown, when mixed, NII. solutions of dianhydride and diamine in amide solvents, it is not possible to obtain a high molecular weight polyamic acid due to side reactions of the interaction of the dianhydride (e.g. pyromellitic dianhydride) with the amide solvent. The aim of the invention is to improve the technology, to obtain high molecular weight polyamido acids, to improve the properties of materials made on the basis of amido acids. This goal is achieved by the fact that, according to the homogeneous method of producing polyamido acids by polycondensation of aromatic tetracarboxylic acid dianhydrides and aromatic diamines, when mixing their solutions in organic solvents, the solutions of aromatic tetracarboxylic acids in acetonitrile and aromatic diamines in the amidic system, in the case of the current, in the case of the current, in the case, the case, the case is not enough, you will have to move the of solvents and acetonitrile, equal to 60:40 30:70, Example 1. To a solution of pyromellitic acid dianhydride (3.3 g) in aceto Nitrile (60 ml) was added with vigorous stirring a solution of 4, V-diaminodiphenyl ether ovogo (W g) and dimethylformamide (kO mL). The reaction is carried out for 30 minutes with constant stirring; a homogeneous viscous solution of polyamic acid is obtained. The intrinsic viscosity of the polyamic acid obtained in dimethylformamide at 25 ° C is 3 2, About dl / g. The volume ratio of solvents in the binary mixture is 60:40 acetonitrile - dimethylformamide). According to a known technique, a polyamic acid solution is made of a durable elastic film. Example 2. Analogously to example 1, but the ratio of solvents in a binary mixture is 50:50. The intrinsic viscosity of the resulting polyamic acid is 1.82 dl / g. Example 3. Similar to example 1, but the ratio of solvents in a binary mixture is 65:35 (acetonitrile dimethylformamide). The intrinsic viscosity of paramilitary polyamic acid Gi1,188 dl / g - p p 4. to a solution of 3.3.4 dianhydride, b-bisoisophenone tetracaparboxylic acid (2.18 g / in acetonitrile, CtO ml) was added with stirring solution i, 4-diaminodiphenyl. ether (1.36 g) in dimethylformamide. ml ;. The reaction is carried out at 15–20 ° C for 15 minutes to obtain a homogeneous viscous polyamic acid solution. The intrinsic viscosity of the resulting polyamic acid in dimethylformamide at 1.72 dl / g. Example 5. To a solution of dianhydride, - benzophenone tetracarboxylic acid (3.7 t ri in acetonitrile (7 P ml), rastor, α-diaminodiphenylmethane 12.33 g) in dimethyl acetamide {30 ml L is added with stirring. The reaction is carried out for 25 minutes at 20 ° Ci A viscous, homogeneous solution of polyamic acid is obtained. Characteristic viscosity of the obtained polyamic acid in dimethylformamide at 25 ° С | 1.98 dl / g. Example 6. To a solution of 3 3 diphenyloxytetracarboxylic acid dianhydride (g) in acetonitrile (65 ml) was added with stirring a solution of i, α-diamine di-diphenyl eyyr (2.46 g) in dimethyl acetamide C35 ml). The reaction is carried out for 30 minutes at 10-15 ° C. A viscous, homogeneous solution of polyamic acid is obtained. The intrinsic viscosity of polyamic acid in dimethylformamide at 25 ° C is 1.92 dl / g. Example 7. 33 g of pyromellitic acid dianhydride are dissolved in

605 acetonitrile, and 30 g of 4-diaminodiphenyl ether are dissolved in 00 ml of dimethylformamide.

The resulting solutions are continuously fed through dispensers into a mixer equipped with a stirrer and a cooling jacket. From the mixer polyamic acid enters the reactor with a stirrer., Divided into sections, and continuously selected through the bottom drain DMF

Known PMDA n DAFE

Note: PMDA - pyromellitic acid dianhydride; BZF - dianhydride D 3i3 -, - benzofenontetrakarbonovy acid; DFO - 3,3 L dianhydride Diphenyloxytetracarboxylic acid; DVFE - 1, -diaminodiphenyl ether; DDFM - 4,4-diaminodiphenylmethane; DMF - dimethylformamide; DMAC - dimethylacetamide; AN - acetonitrile,

As can be seen from the table, when using the proposed method of obtaining the intrinsic viscosity by a polynomial choke; the polyamic acid removal rate from the reactor is 15 g / min. A homogeneous, viscous solution of polyamic acid is obtained, which has a characteristic viscosity in dimethylformamide at 25 ° C | 1.06 dl / g.

The table shows the comparative characteristics of the properties of polyamic acids obtained by the known and proposed methods.

Homogen-0.15-0.35 lycondensation

amic acid c. times higher than when homogeneous polycondensation in an amide solvent by a known method.

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The preparation of high molecular weight poly (polymeido acid) provides an increase in the quality of Pleno {coatings and fibers obtained on their basis.

It should also be noted that the polyamic acids obtained by the proposed method have high homogeneity and do not contain gel-like particles observed in a heterogeneous process for the production of polyamic acids, in industry, claims

A homogeneous process for the preparation of polyamic acids by polycondensation .. of aromatic tetracarbonate dihydrides -. boven acids and aromatic diamines when mixing their solutions in organic solvents, o tl and h a 8

In order to improve the technology, to increase the molecular weight of polyamic acids and to improve the properties of materials based on them, aromatic tetracarbonic acid dianhydrides in acetonitrile and aromatic diamines in amide solvents are mixed at a volume ratio amide solvents and .acetonitrile, equal to SOt tO-SOtyO.

Sources of information taken into account in the examination

1. The UK patent number 1162203, cl. C 3 P, published. 1970.

2. US patent number 3179630,

to., 260-30.2, published. 19b5 (prototype)

Claims (1)

• Claim A homogeneous method for producing polyamido acids by polycondensation of ₁₅ aromatic tetracarboxylic acid dianhydrides and aromatic diamines by mixing their solutions in organic solvents, with the exception of the fact that, in order to improve technology, increase the molecular weight of polyamido acids and improve The properties of the materials obtained on their basis are subjected to mixing with solutions of aromatic tetracar dianhydrides, boronic acids in acetonitrile and aromatic diamines in amide solvents at a volume ratio of am id solvents and acetonitrile equal to 60: 40-30: 70.