DD284884A5 - MIXTURE OF CUPFER COMPOUNDS IN THE PRESENCE OF POTASSIUM IDID AND POLYAMIDE - Google Patents

Abstract

The invention relates to a mixture of copper compounds in the presence of potassium iodide and polyamide. The invention relates to a mixture of copper compounds in the presence of potassium iodide and polyamide, which is used for the thermo-oxidative stabilization including light stabilization of polyamide, which is primarily processed in the chemical fiber industry. The invention relates to a mixture of copper compounds in the presence of potassium iodide and polyamide, which is characterized in that the mixture consists of * glycol ether / ether glycolate, 2-1010 3% Cu, * moles KOH / mol Cu, wherein the mass ratios of the constituents to the dried polyamide granules are related. The p H value of the mixture is in a range of 7.5 to 8.5. {Mixture; Polyamide; inorganic copper compounds; Glycol ether / Etherglycolat; potassium iodide; alkali hydroxide; PH value; Corrosion; Thermooxydation; Light Stabilization}

Description

Field of application of the invention - «L

The invention relates to a mixture of copper compounds in the presence of potassium iodide and polyamide, which is used for the thermo-oxidative stabilization including light stabilization of polyamide, which is processed primarily in the chemical fiber industry.

Characteristic of the known state of the art

It is known that the thermo oxy dative damage of high polymers, autoxidative or accelerated, limits the use of polymer material in technical use when reaching the activation energy.

Below the thermal decomposition, light quanta lead to polymer degradation. The chemistry of both types of degradation is radical. The loss of chemical structure entails the loss of physical structure of the polymers. The result is yellowing, scrambling, premature decomposition of the material.

If polyamide is provided as fine silk, coarse silk, tapes or shaped pieces for technical use, it is state of the art to stabilize thermo-oxidatively and photochemically.

For this purpose, for example, phosphorus compounds lower oxidation state, and sterically hindered phenols and sulfur compounds used.

According to the patent DE 2254408, for example, a multicomponent system consisting of a small proportion of a copper halide, alkali iodide, a large proportion of di-tert-butyl-cresol and triphenylphosphine is powdered or sprayed onto the polyamide granules according to different dosing variants.

According to EP-PS 275910, polyamides stabilized against thermooxidation contain reaction products of diphenylamine or phenothiazine with isopropene phenols or bisphenols. The most preferred range is 0.2-5%, based on polyamide.

It is also known that in the thermal oxidation and the photo-oxidative parallel reaction, the hydroperoxide is formed as a common starting point for the chain degradation reaction. By metal compounds with stable single-electron

Redox potentials, this primary oxidation product is disproportionated into inert oxo and peroxo radicals. j j

However, the metals used Fe, Co, Mn have the disadvantage that their higher oxidation states are dark in color.

Most frequently, copper compounds as main components, which also cause sufficient light stability of the polyamic fiber, are used in a variety together with auxiliary substances.

For example, according to the Romanian patent RO 81 852, the polyamide granules are mixed stepwise with butyl stearate and then with a grinding of Cu (ac) ₂ , caprolactam and NaCl.

In connection with these stabilizer systems with polyamide as granules, melt and silks, however, disruptive side effects such as copper deposits and red discoloration of the silk, melt viscosity losses and inhomogeneities of the antioxidant in pulverulent applications arise in the production process.

It has also been shown that in the long-term use of such stabilizer systems corrosive phenomena occur on storage containers, metering and Extrusionseinrichiungen and other components. Uneconomically short service lives of individual device elements of less than 1 year can be observed. Nevertheless, in order to enable an optimal driving style, a higher technical effort is absolutely necessary. So it is quite common, particularly corrosion-endangered assemblies with a surface protection,: u provided.

Object of the invention

The object of the invention is to improve the thermal and light stabilization effect while avoiding disruptive side effects.

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Explanation of the essence of the invention The object of the invention is, without increased technical complexity in the use of copper-containing halide mixtures

economically acceptable service life of all parts of the plant in the production of thermooxidation stable and light stable

To reach polyamide.

According to the invention the object is achieved in that a mixture of copper compounds in the presence of potassium iodide and polyamide is used, which is characterized in that the mixture of 0.2-0.4% glycol ether / ether glycolate, 2-10 · 10 ~ ³ % Cu, 0.9-1.3 moles KOH / mol Cu, wherein the mass ratios of the constituents are based on the dried polyamide granules. Cu-Il salts, preferably CuBr ₂ , are dissolved in a glycol ether / ether glycolate mixture and chemically modified. The resulting viscous stabilizer mixture is then mixed in a certain amount ratio with the extracted and dried polyamide granules and forcibly homogenized in the extruder in the polyamide melt.

It is expedient to raise the stabilizer uniformly on the surface of the granules, wherein conventional continuous or discontinuous mixing devices can be used.

In this phase, specific absorption and diffusion processes of the dissolved stabilizer components and of the triglycol ether begin.

The stabilized product is characterized by:

0.2 to 0.4% glycol ether / ether glycolate, preferably 0.25 to 0.35%

2 to 10 x 10 ^-3 % Cu, preferably 5 to 7 x 10 ^-3 %

0.9 to 1.3 moles of KOH per mole of Cu, preferably 0.95 to 1.15 moles

This KOH amount determines the glycol content in the glycol ether and the pH of the stabilizer solution,

- further 0,06 to 0,09% Kl

Old mass ratios of each compound refer to dried polyamide.

In the preparation of the stabilizer mixture, the specified KOH mixture is dissolved in triethylene glycol, which partially forms the alkoxide.

Triethylene glycol is understood as meaning both pure triethyleneglycol mixed with admixtures of lower and higher glycol ethers.

It was surprising that the voluminous hydroxy-Cu-II salts which form on entry of CuBr ₂ or Cu (NOj) ₂ in glycolate undergo a triglycol-soluble compound after the addition of Kl, which gives the mixture an oily consistency. After prolonged standing at room temperature or at temperatures of about 5 ^C C, no precipitation occurs, so that a trouble-free dosage is ensured by pumping. The triethylene glycol used as the carrier liquid can take up to 1.7% of Cu when using CuBr ₂ as the dissolved hydroxy compound.

The pH should preferably be 7.5 to 8.5.

As is known, the presence of heavy metal ions, for example Cu **, enhances the corrosive attack of halide solutions on various metallic materials. For materials that are protected by a passive layer, pitting and stress corrosion cracking occur in addition to even removal.

Surprisingly, the alkaline solution of the stabilizer formulation with CuBr ₂ in the electrochemical corrosion test, for example in CrNi steels, showed only an insignificant tendency to corrode.

The dissolution reaction of Cu-Il salts in anhydrous ether glycols leads to the formation of strong anhydrosilic acids, which are not sufficiently neutralized by weakly basic amines or by the basic function of the polyamide in the melt.

Although high pH values, greater than 8.5, bring complete freedom from corrosion, the spinning of such a modified polyamide is not without problems.

Undesirable post-condensation phenomena can not always be ruled out. Due to the pH of the mixture according to the invention, both the acidity-related corrosion at metering and extrusion equipment and the acidity-related polyamide degradation can be favorably influenced. The pH of the mixture is adjusted depending on the Carboxylendgruppengehallgeham of the polyamide.

The pH control of the mixture is carried out with universal test strips or other conventional methods.

It must not be ignored that this pH determination is carried out in a nonaqueous system, yet the values obtained are sufficiently reproducible in the analytical sense and suitable for a control.

As an additional effect, it has been observed that the redox potential of the reactants in the polyamide melt stabilized according to the invention does not permit interfering metallic copper deposits on melt-carrying tube walls or spinnerets; An additional organic auxiliary stabilizer as complexing agent could therefore be dispensed with.

The visible sign of the presence of free iodine in the mixture suitable for use is its brown color, which, however, completely disappears during mixing and spinning of the polyamide granules. The transition of iodine vapors into the gas space is excluded.

The sum of all additives of 0.4 to 0.5% of the easily processed liquid mixture to the polyamide leads to no significant P "loss in the spinning process.

embodiments

The invention will be illustrated by 2 examples.

example 1

For the stabilization of 100t polyamide granules, the procedure was as follows:

In a mixing vessel 352 kg of triethylene glycol, water content less than 1%, to fill. At 80 ° C and constant stirring 6.0 kg of solid KOH are added in portions. After a stirring time of 60 minutes, the portionwise addition of 23.5 kg of CuBr _{2 is carried out} .

The chemical conversion into the blue-green hydroxy-Cu-Il-bromide is complete after 60 min at 80 "C with constant stirring and the voluminous precipitate homogeneous.

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Then the temperature is raised to 97 ° C. and 75 kg of Kl are gradually introduced into the solution. Emerging vapors are he to dissipate the steam room. After a reaction time of 120min, in which is stirred constantly, the precipitate and s Kl are completely dissolved.

The still hot batch is cooled to ambient temperature via a coarse metal wire filter in storage tanks. Analysis of the stabilizer acid gave the following values:

-Salary: 1.44% -Value: 7.6 at the dosing temperature: 1,327 kg / l -ssergehalt: 0.4%

continuous operation 4.31 stabilizer solution per 11 granules were applied with a bellows metering pump, ansiv mixed with the granules and fed through a reservoir to the extruders and spun. The SRW silk, "itex f 280, is suitable for technical applications and has the following values:

Resistance to heat (WB value):

stabilized: 98%

stabilized: 41%

non-resistant (LB value):

-tabilized: 95%

stabilized: 80%

If the copper content of the granules was 7.5 × 10 ^-3 , there were no copper deposits disturbing the spinning process.

> The specified values represent mean values of the production control.

Vedders in the storage containers of the alkaline mixture or of the modified granulate or on other contaminated parts of the vilage showed corrosion phenomena after long-term stabilization of the polyamide.

It is customary to specify the WB value and the LB value as the breaking force ratio before and after a heat treatment or exposure.

reported values refer to a 2-hour heat treatment of the threads in standard climate at 170 ⁰ C (WB value) as an exposure with a xenon at 29O ⁰ C, 65% rel. Humidity and 200 hours.

game 2

- discontinuous modification of 750 kg batches, 35 stabilizer batches were prepared according to the following procedure d processed.

s 2350ml triethylene glycol and 68g KOH forms the glycol ether / ether glycolate mixture. The batch temperature is 70 ⁰ C.

At this temperature and with constant stirring, 172 g of CuBr ₂ are mixed into the carrier liquid. After 1.5 h, the formation of the voluminous Cu hydroxy salt is completed. Subsequently, 563 g of Kl are added and the temperature of the -chung increased to 95 ° C. The precipitation and the solid Kl dissolve in 90min.

Analysis showed:

od-colored, oily, clear solution

": u content: 1.49 ± 0.05% as a mean of the 35 approaches

Water content: 0.2%

 In a rotary drum dryer, the mixture was grown at 50 ° C on the dried granule batch of 750 kg and nogenisiert.

a Cu content in the granules of 6.5 × 10 ^-3 % was found.

other test values:

-Value: 99% equal (untreated): 47% Value: 98% equal (untreated): 80%

The test values were determined under the test conditions mentioned in Example 1.

Claims (4)

claims: .1. Mixture of copper compounds in the presence of potassium iodide and polyamide in that the mixture of 0.2-0.4% glycol ether / ether glycolate, 2-10 × 10 ^-3 % Cu, 0.9-1.3 moles   KOH / mol Cu, wherein the mass ratios of the components to the dried   Polyamide granules are related. \ Second Mixture of copper compounds in the presence of potassium iodide and polyamide according to claim 1, characterized in that the pH is in the range 7.5 to 8.5. 3. Mixture of copper compounds in the presence of potassium iodide and polyamide according to claim 1 and 2, characterized by containing Cu of 5-7 x 10 ^-3 % and glycol ether / ether glycolate in the f. Limits of 0.25-0.35%. 4. Mixture of copper compounds in the presence of potassium iodide and polyamide according to claim 1 to 3, characterized in that as starting compounds for the copper CuBr ₂ or Cu (NO ₃ I ₂ I be used. ~ $ \