DE749747C - Process for the production of highly condensed polyamides from diamines and dicarboxylic acids - Google Patents

Description

There are already known products that due to the mutual action of certain dibasic acids and certain organic ones Diamines are formed. Most of these are cyclic amides of low molecular weight. In some cases it was assumed that polymers were present, however, they were either of low molecular weight or they were completely infusible and insoluble. In no event has any intended use for these compounds result. (Cf. Ann. 232, 227 [18S6]; Ber, "46, 2504 [1913]; Bei /. 5, 247 [rS / 2]; Bcr. 17,

»5,137 [1S84]; Ber. 27R, 403 [1894]; Ann. 347, I / [19 ° 6]; Ann. 392, 92 [191: 2]; Journ. Aiiu'r. Chem. Soc. 47, 2614 [1925]; Chem. Reviews S, 370 fr93r].)

It has now been found that one can obtain hole-condensed polyamides in the compound salt of the above-mentioned compounds, which are distinguished by their manifold commercial usability in that they can be processed into mats, films, tapes. These highly condensed polyamides are hereinafter referred to in ^§ 5 as "Siipet-polyamide". A number of superpolvamids have already been described in the literature. (See. Journ. Amer. Chem. Soc. 54 1506-69, ^l 579-S7 [1932 !, Silk Journ. Rayon World S, 33-34, and 41-42 Textile recorder 49. [1931J.) The there specified polymers or ' Superpolymers are derived either from an amino acid or from polyesters, polyanhydrides, and mixed polyester polyamides.

In the method according to the invention, it is \ ^r on suitable., Identified in more detail below diamines and dicarboxylic acids and amide-forming derivatives thereof or or out.

For the present purpose, it appears advantageous to label the various reaction participants with the aid of their radical lengths. The radical of a carboxylic acid is used to adjust _;

lent the T-Gnippen after the acidic oil had split off the remainder, below the radical length, is the carbon atom number in the chain of the Radicals. So the radical of adipic acid is -CH

- CO —Cl!., ^S _CH _S —ClL- CO-,

calculating its radical length (>. EntS]), the radical of a diamine is that according to Abspal-Hing each of a hydrogen atom from both amino groups and the remaining residue Radical is the length of the atomic number of C and X in the chain of the radical. Such is the radical iles pentamethylene diamine

- XII — CHo- CHo-

C Ho -CIL-CIT ₂ -XII-.

its radical length is 7.

According to the invention, one or more diamines with at least one free hydrogen atom on each nitrogen atom, which contain the amino group bonded to an aliphatic carbon atom and have a radical length of at least O, and one or more dicarboxylic acids and l) between. or their amide-forming descendants with a radical length of at least 5 or less than 4 in approximately equimolecular amounts to one another at amicl-forming temperatures, preferably 120 to 2 () 0 °. at least until, on touching the surface of a molten sample with a rod and pulling it away, a small amount of the mass adheres to the rod and remains in connection with the majority of the melt, forming a thread, without tearing, or so long, until the true viscosity of the product is at least 0.4. preferably on

₊ o at least 0.5, has risen.

Particularly preferred here are diamines of the formula XH ₃ -CIL-R-CH ₂ -XH ₂ and dicarboxylic acids of the formula

HOOC-CHo • R '- CHo • COOH

or amide-forming derivatives thereof, where R and R 'are divalent hydrocarbon radicals and R is a chain length of at least two carbon atoms bcso sits. The most valuable superpolyamides obtainable in this way are those which is different from diamines of the formula

XH ₂ . iCHsVNH «,

where χ at least = 4, and of bicarbonic acids the formula

HOOC- (, CHo) ,. · COOH,

where y is at least 3. derive. Go examples of particularly suitable dicarboxylic acids are the following, where the radical lengths are enclosed in brackets: Cikuarsäurc. Adipic acid ((>), pimelic acid (7), suberic acid (8), azelaic acid (y), sebacic acid (to), brassylic acid (13), tetradccanedioic acid (14), octadecanedioic acid (r8) and p-phemiendiacetic acid ( 8th).

Examples of suitable amide-forming descendants of dicarboxylic acids are: Oxalic acid diethyl ester (2). Diethyl adipate (6), diphenyl sebacate (io), di-m-cresyl octadecanedioate (18), adipic anhydride (ö). Sebacic anhydride (io), Adipic acid monomethyl ester (Y>) and adipyl chloride (C)). ''75

Examples of suitable diamines are: tetramethylenediamine (6), pentamethylenediamine (7). Hexamethylene diamine (8), decamethylene diamine ( 12), tridecamethylene diamine (15), octadecamethylene diamine (-2O) and p-xylene diamine (_S).

In the Polyamidbilduug the use of a slight excess canoe, up to about 5 ° / _0th in diamhi or dicarboxylic acid prove to be advantageous. It is also possible to work in the presence or absence of solvents or catalysts, preferably under non-oxidizing conditions and advantageously partially in closed vessels, that is to say at times under pressure. In order to facilitate the completion of the reaction, it is advisable to take precautions to avoid alcohol, water or hydrochloric acid. to be removed depending on which substance is split off. Furthermore, an inert gas can be introduced, antioxidants such as syringic acid can be added and the reaction can be carried out under reduced pressure. The optionally added catalysts include inorganic substances with an alkaline reaction, such as oxides and carbonates, or acidic substances, for example halogen salts of polyvalent metals, such as tin dichloride.

The diamine and the dicarboxylic acid or its amide-forming derivative can be used directly react with each other, wherever the temperature is increased sufficiently, to maintain the required liquid and homogeneous state of the mass. The viscosity of the molten mass increases as the reaction proceeds. If one works in this way, the examination of the conversion into the superpolymer can easily be carried out in the manner touching the surface of the molten polymer with a stick and then pulls it away. In the presence of superpolymers, a small amount adheres to the stalxi and remains in Connects to the bulk of the melt without tearing. This simple one

Trabe can easily serve to the ΛΌΙl-suiiitlijilcci.t. ck-i *. display reaction. It pretends that this is only within) an appropriate temperature range 5 above the melting point applies: at very high temperatures the mass becomes so thin that that she no longer had on the staff. Mine another usable sample, "the has the merit of quantitative results too

ίο deliver consists in identifying-the true Viscosi'tät in the one described below Way. In general, the desired polymerisation stage is only achieved when the true viscosity is at least 0.4.

If diamines and alkyl esters of dicarboxylic acids are allowed to act on one another directly under reflux or in a closed vessel, the reaction is advantageously carried out at a temperature above ^{10 ° C.} , for example from 160 to 18o ~. The initially educated. Polymers are separated out, so that the temperature is increased above 200 ° up to 290 ° in order to keep the cup homogeneous. It is set in alcohol freedom, is removed by use of Fraktiom'erkolonrien or by alternately opening and closing or evacuating the vessel. The first part of the reaction is preferably carried out under pressure in a closed vessel which is then opened or evacuated in order to remove the alcohol.

If you start from diamines and the aryl esters of dicarboxylic acids, then the begins Exposure at a lower temperature than in the case of the alkyl esters. So you can at the production of the super polyamide from pentamethylenediamine and ■ sebacic acid Instead of sebacic acid diethyl ester, advantageously use siibacic acid diphenyl ester, since the latter reacts more quickly and completely ex. In addition, the released phenol has a considerably softening and loosening effect on the superpolyamide and helps to make the reaction mixture homogeneous. It is often possible to find suitable super " polyamides by simply heating phenyl ester and diamine in one

closed vessel. for example to 200 ⁰ , without it being necessary to remove the liberated phenol.

The achievement of the final stages of these immediate melting reactions can be Accelerate by stirring, for example by introducing an inert, preferably preheated gas, such as nitrogen.

One can also successfully use certain "fluids" which are suitable for both the

fio starting materials as well as solvents which are inert for the reaction product place. Suitable solvents sin.i: Phenol.- o-, m- and p-cresol, the xylenols .. p-tertiary butylphenol, thymol and o-oxydiplienyl. The monohydric phenols are the preferred type of solvent used represent.

If a solvent is used, as the reaction proceeds, the the viscosity of the reaction mixture, while its electrical conductivity sinks. With the help of suitable devices (Yiscosin suppliers and conductivity numbers) the change in these properties can be measured continuously. The true iscosity is defined by the

Expression — τ ·, -, where η _{τ is} the viscosity eiiit-r

0.5 "/" strength solution of the polyamide in m-cresol, divided by the viscosity of m-cresol at the same temperature and in the same viscosity unit, while C is the concentration, expressed in g of polyamide per 100 ecm of solution The test is carried out in such a way that a measured amount of the reaction mass is removed, any solvent present is removed by precipitation with alcohol, the polyamide is dissolved in so much m-cresol that the concentration is 0.5 ⁰ Z ₀ , and the viscosity Measures at 2y The super polyamides with a true viscosity between 0.5 and 2.0 are found to be particularly useful.

If you work with a solvent, a concentration of about is recommended ι part solvent to 1 part Diam'in plus To apply acid. Usually you take the reaction at 200 to -260 ° all at once A vessel that allows the removal of water, etc. Is the temperature above the boiling point of the solvent, the process is carried out under a pressure, which is low enough. to distill off the water, etc. with ease, but high enough not to show any loss Prevent solvents. In any case one works advantageously under an indiff. reuten gas, such as nitrogen, that one is on reads continuously through the mixture.

As already mentioned, the super polyamides can also be obtained from the chlorides of dicarboxylic acids and manufacture diamines. The reaction then proceeds extremely quickly and is preferably moderated by using an inert solvent such as benzene. In order to absorb the released hydrochloric acid, one can add basic substances or other acid-binding agents, for example alkali hydro- 12p xides or carbonates, oxides or carbonates of the alkaline earths and tertiary bases,

like pyridine. The polyamides formed in this way often have a comparatively low molecular weight, but can be converted into suitable superpolyamides. by placing them on high temperature, e.g. B. 200 to 290 ⁰ , heated under conditions that allow the rapid removal of volatile substances.

Salts of dicarboxylic acids, e.g. B. alkali salts can also be used, provided that one adds a substance that combines with the alkali metal. In Similarly, in place of the diamines, one can also use their salts, which are obtained by addition from acids, e.g. B. the hydrochlorides and carbamates, use.

The average molecular weights of the superpolyamides according to the invention are difficult to determine, but likely to be somewhere between 7,000 and 20,000. The super polyamides are tougher and more flexible than the low molecular weight polyamides and therefore have greater commercial utility. Below her When examined with X-rays, they provide sharp diagrams for melting points crystalline powder, which is evidence of its crystalline structure in compact form Condition is. In phenol. Formic acid and hot glacial acetic acid dissolve while they are insoluble in most other common organic solvents are. In a finely divided state they are made up of strong mineral acids, such as hydrochloric or Sulfuric acid, attacked quickly; they become the dicarboxylic acids and diamines, from which they are derived, saponified. They are more resistant to strong caustic alkalis, but they also saponify these substances in the end.

The approximate melting points when determined in air on a heated metal block can be seen from the table below. If the determination takes place in the absence of air in the glass tube, the melting points are 5 to 20 ^° higher.

Melting point

i66 ^c

Super polyamides

Pentamethylenediamine and
Sebacic acid

Pentamethylenediamine and
Dodecamethylene dicarboxylic acid

Pentamethylenediamine and
Hexamethylenedicarboxylic acid

Hexamethylenediamine and

Adipic acid 24S ⁰

Deeamethylenediamine and

Adipic acid. 230 ⁰

Density 1.0S

1.05 ι .04 j In the following the invention is illustrated by means of examples in which the numerical data Parts by weight mean.

example 1

Bring a mixture of 14.8 parts of pentamethylenediamine, 29.3 parts of sebacic acid and 44 parts of technical xylenol in a vessel equipped with a cell for determining conductivity, a device for recycling evaporated solvent, a feed line for nitrogen, a thermometer and a Viscometer is provided and heated the mixture with the help of the vapors of boiling naphthalene for 13 hours! to 218 ⁰ . During this time, conductivity and viscosity are measured in appropriate spaces. After the 13 hours had elapsed, the true viscosity was 0.62, while the conductivity had dropped from an initial value of 0.0028 ohms " ¹ to a final value of 0.000053 ohms" ^1. The entire reaction mass is now Gradually poured into a large amount of ethyl alcohol while stirring. The superpolyamide precipitates as a granular, white powder, is filtered off, washed with alcohol and dried. Its melting point is 185 to 15 °.

After the analysis, the above product corresponds to the formula

[-NH- (CHo) ₅ -NH-

CO- (CHo) ₈ -CO-] _x .

When saponified with hydrochloric acid, it breaks down into sebacic acid and hydrochloric acid pentamethylenediamine.

Example 2

A mixture of 26.4 parts of hexamethylenediamine, 33.2 parts of adipic acid and 60 parts of technical grade xylenol (boiling point 218 to 223 ⁰ ) is placed in a device of the type described in Example 1 and heated for 7 hours with the aid of boiling naphthalene vapors . At this point the true viscosity is 0.67 and the conductivity is 0.000065 Ohnv ¹ . The super polymer is then precipitated in alcohol; it shows a melting point of 248 ^° .

Example 3

a) Equivalent amounts of pentamethylenediamine and sebacic acid are heated in a closed glass vessel with the aid of a bath for 1 hour to 220 to 230 ^° , a polyamide of low molecular weight being formed. Then the pressure in the vessel is reduced to τ mm and the low-

Molecular polyamide heated to 230 to 240 ° for a further 3 hours. The homogeneous reaction mixture gradually becomes more viscous as the molecular weight of the Polyamide is increasing. After the specified time has elapsed, the molten mass of the superpolymer pentamethylene sebacinamide barely liquid.

b) The mixture is heated 28.9 parts of sebacic acid and 15.4 parts (5 ° / o excess) pentamethylenediamine 2 hours in a sealed glass vessel to 220 to 230 ^0th The vessel is then evacuated and the heating to 220 to 230 ⁰ under 1 mm pressure is continued for two more hours, the superpolyamide being obtained.

c) The mixture is heated 5 parts pentamethylenediamine and 10.39 parts (S ° / o excess) sebacic acid for 2 hours in a sealed glass vessel to 230 to 240 ^0th Then evacuate the vessel and continue heating under a pressure of 1 mm for an additional hour to obtain the superpolyamide.

d) Equivalent amounts of sebaic acid and pentamethylenediamine are heated in a closed glass vessel to 230 to 240 ^{0 for} 2 hours. The vessel is then opened to allow the water to distill out and heating is continued for 1 hour, after which the superpolyamide is formed.

e) The mixture is heated equivalent amounts of sebacic acid and pentamethylenediamine under atmospheric pressure at 200 ⁰ in a glass vessel provided with a reflux condenser. The cooler is then removed to allow the water to distill out and ^{heated to 230 to 240 0 for a} further 6 hours, while a slow stream of nitrogen is passed over the surface of the mixture at the same time. The product obtained is a super polyamide.

Example 4

Equivalent amounts of pentamethylenediamine and hexadecamethylenedicarboxylic acid _{diethyl ester, C 2} H ₅ OOC · (CH ₂ ) io 'COOC ₂ H ₁ - ;, in a closed glass vessel, are heated to 100 to ιSo ^{0 for} 23 hours. The vessel is then opened and heated to 170 to 180 ° for a further 3 hours in order to allow the alcohol to distil off. The vessel is closed again and heating is continued at a temperature of 230 to 240 ° S hours under a pressure of 1 mm. The fabric is formed, the super polymeric Diämid from Hcxadecamethylendicarbonsäure and pentamethylenediamine is obtained upon cooling as a slightly brownish, opaque hard mass, which is transparent at 167 suddenly ^0th

Example 5

Equivalent amounts of pentamethylenediamine and dodecamethylenedicarboxylic acid diethyl ester, C ₂ H ₅ OOC · (CH ₂ ) ₁₂ · COOC ₂ H ₃ , are heated to 200 to 240 ° for 16 hours in a closed glass vessel. The vessel is then evacuated and heated for a further 8 hours at 240 ^° under a vacuum of ι mm. The high polymer amide formed from dodecamethylene dicarboxylic acid and pentamethylene diamine is obtained in quantitative yield; It is a hard, opaque mass that melts at 170 ^0th

Example 6

Bringing a mixture of 150 parts Adipinsäuredikresylester, 54 parts of hexamethylenediamine and ι Oo parts of m-cresol in a reaction vessel which is heated for 3 hours at 235 ⁰ for the "evacuation and Complete. Upon opening of the vessel, the reaction product proves to be of an almost colorless, viscous mass. It is poured gradually into a large amount of ethyl alcohol, whereby the superpolyamide precipitates in the form of a fine, white powder. This substance has a true viscosity of 0.64. If no cresol is added to the original reaction mixture, Thus the superpolyamide obtained is a colorless, fairly hard mass. It can be cleaned by grinding and washing with alcohol, after which the true viscosity is 0.54.

Claims (4)

Patent claims: i. Process for the production of highly condensed polyamides, characterized in that that one or more diamines with at least one free hydrogen atom ah every nitrogen atom which the amino group to an aliphatic Contain carbon atoms bonded and have a radical length of at least - 'Stens 6, and one or more Dicarboxylic acids and / or their amide- ^ forming descendants with a radi- '■ " call length of at least 5 or less than 4 in approximately equimolecular amounts, with each other on amide-forming. preferably heated to a temperature of 120 to 290 °, at least at least so long until when touching the surface of a molten sample mi ι a stick and pulling it away a small amount of the measure on that Rod adheres and under thread formation in connection with the main shaft of the Melt stays without cracking, or something long until the true viscosity of the product to at least ".4., preferably to at least 0.5. 2. λ "experienced according to claim 1. characterized / feirhneti, that one Xegelizcugnisse such as alcohol, water or hydrogen chloride» removed during the course of the reaction. 3. The method according to claim 1 and 2, characterized in that the reaction is carried out in (the presence of an inert solvent, preferably a monohydric phenol. J 4. The method according to claim 1 to 3, | characterized in that the | Carries out reaction in the absence of oxygen. λ'erfahren according to claim 1 to 4, through this reaction leads. marked,
temporarily under that one. Pressure through To distinguish the subject of the application from the state of the art, the granting procedure the following publications have been considered: Chemisches Centralblatt 1932, II, 194 paragraph 2, 195 paragraph 2; I ₁ 157 para. 6 and the ■ corresponding original literature;
Ber. 46 (1913), 2504 and 2505. according to> i <£ kt m urn