DE2011678A1 - High viscosity polyamide and process for its production - Google Patents

Description

The invention relates to the production of polyamide compositions with a high melt viscosity. In the method according to the invention, a polyamide is reacted with a polyepoxy compound, the one vinyl epoxy group and 1-3 vinylene epoxy groups owns. The polyamide compositions made by the process of this invention are particularly useful in manufacture of formations.

Thermoplastic linear polyamides such as nylon and nylon 66 have excellent processability in the Melt. Because of these properties, it is used in large quantities these polyamides are processed into moldings. The Hersteliting this thermoplastic linear polyamidö takes place normally

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wisely by melt polymerization. The high viscosity of the Polymer, normally obtained by melt polymerization, is useful to make fibers, films and some injection moldings to manufacture. However, a higher melt viscosity is required to produce numerous moldings. This is particularly true for the extrusion of round bars, tubes, sheet materials and shapes with thick sections as well as for blowing hollow containers. The dimensional stability of the extruded polymers with lower Melt viscosity is unsatisfactory and there is a tendency to deform before solidification of the polymer,

Attempts have been made to use thermoplastic polyamides to produce with a high melt viscosity. Some methods of making high melt viscosity polyamides have already been proposed. One such method is to increase the melt viscosity by increasing the To increase the degree of polymerization of the polyamide. At this The method used during melt polymerization is the polymerization temperature and the degree of pressure reduction is significantly increased. The degree of polymerization increases, and you obtains a polymer with a high melt viscosity. However, this method has many disadvantages. It requires one longer reaction time, and the adverse effect on the polymer due to excessive heat application- leads to the fact that the process is impractical for industrial purposes. In addition, the polymer has a high melt viscosity, that obtained by this method is not sufficient Viscosity stability and tends because of a very small

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Amount of moisture during molding to be adversely affected. Even when deformed under bubbles, the product possesses high melt viscosity polymers produced by this process lack dimensional stability.

Another method that has been proposed is to bind the polyamide molecules together so that the melt viscosity increases. Epoxy compounds are used as additives for this purpose, Isocyanate compounds and peroxides used. Epoxy compounds that are easy to synthesize and handle are preferred in this process. However, it was found that the viscosity increase in a thermoplastic linear polyamide with an epoxy compound has certain disadvantages. When a polyepoxy compound with at least two vinyl epoxy groups, as are commonly used for the manufacture of epoxy resins, in one melted one State with a polyamide with a melting point of is mixed at least 15 ° C, the compounds react with each other before they are sufficiently mixed with each other. There are excessive local reactions that produce a non-uniform .Cause increase in molecular weight. Venn the polyamides with a large degree of heterogeneity be shaped by extrusion in the melt, it is impossible to obtain homogeneous objects with a smooth surface. These objects are not just from the point of view their appearance, but also with regard to their mechanical properties are unsatisfactory.

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On the other hand, when polyepoxy compounds are the only vinylene epoxy groups contained, as described for example in British patent specification 83I 207, are used the heterogeneous reaction, which increases the molecular weight, generally does not take place. The effect of increasing the However, the melt viscosity is not sufficient. Even if the oil viscosity of a polyamide with such epoxy compounds is increased, it is difficult to obtain satisfactory moldings. Hence the use of such Polyepoxy compound not industrially feasible.

Accordingly, it is an object of this invention to provide a method for making polyamide compositions having high melt viscosity obtain. Another aim is to provide a method for producing polyamide compositions with better homogeneity Deform and get a flow index less than 10. Other goals and benefits are evident from the following Description apparently.

The object on which the present invention is based is achieved by the process according to the invention for producing a Polyamide composition with high melt viscosity dissolved in which a polyepoxy compound, which is a vinyl epoxy group and 1-3 Contains vinylene epoxy groups, reacts with a thermoplastic linear polyamide.

The term "vinyl epoxy group" means in this specification an epoxy radical, in which the epoxy group with 3 water

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substance is connected to atoms «, This vinyl epoxy group is made by the following formula is given:

'Xl -VI

The term "vinylene epoxy group" is used in the specification 6o used that he was a divalent epoxy group with a hydrogen atom on each carbon atom of the epoxy ring means. The vinylene epoxy group is represented by the following Formula reproduced "

rfii ride

KjXX Vjxx

Those used in the method of the present invention Polyepoxy compounds have one vinyl epoxy group and one vinylene epoxy group. The polyepoxy compounds can be represented by the following general formula

CH "- CH.

CH - CH-

- CH - CH-

IH-I

CH - CH -

CH C

where R ^ and R ^ are identical or different and mean lower alkylene groups, low molecular weight Oxyaikylengrüppeai Cyöiö « ^Λ alkylengrupperi» Endocyeloalky ^ group, and arylene radicals, -R ^; hastily nfedig ^ m ^ lieikulare

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means and

and

together sT; it the carbon atoms of the

K ₀

May form Vinylenepoxygruppe ez ^ a 5- or 6- ^ üedrige cycloalkylene group Scv-sc of the carbon atoms in R _1, R ^ ¹ ^ ¹⁰ * R beträft two to 12, a is an Ad ^ number of 12, a ra integer from 1-2. and ρ is an integer from T - 3 .

Examples of a polyfunctional epoxy compound of the above formula which are particularly useful for the present invention are as follows: · ·. *

Vinyl cyclohexene dioxide

Epoxydicyclopentyiglycidyl & ther

CH ₃ -CH - CH-CH ₉ -CH. -

0;

<έ

0 "

CH -

_> 4-hexadiene dioxide

i, 4-Epoiycyclohexylglycidyl Cither

CH ₂ - OH ~ Cd - CH - CK ₀ - Cu - CH - CHo

ν ν \ /

^ü r

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oxide

BAD ORfGlMAL

¹ V

- ^ CH ₂ -CH-Ci-CH ₃

CH-Gi-C-Ic, »» ^ f ^ (2,3epox

\ / * phenyl glycidyl other

As; Crosslinking agents in the method of the present invention Polyepoxy compounds used in the invention contain only one vinyl epoxy group. Polyepoxy compounds that have more than one. Vinyl epoxy group are unsuitable because they cause a non-uniform increase in the melt viscosity of the polyamide cause, as stated above. It is also essential that the polyepoxy compounds used in the present invention Contain 1-3 vinylene epoxy groups. These vinylene epoxy groups are required in order to achieve crosslinking and thereby increasing the apparent viscosity of the polyamide compounds. It should be noted that polyepoxy compounds, which have no vinyl epoxy group and only a vinylene epoxy group are not sufficiently effective as crosslinking agents.

The reason why a homogeneous polyamide with a high _ Melt viscosity obtained by the process of the present invention is not sufficiently clear. It will, however assumed that the reason is as follows. Depending on the ν

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Structure of an epoxy group is the reactivity with polyamide end groups, namely, the amino group and the carboxyl group are different when the polyepoxy compounds used in the invention can be added to a polyamide, and it is believed that the vinyl epoxy groups that react more easily than the vinylene epoxy group, quickly with the amino end groups of the polyamide react. The polyepoxy compound is thereby attached to the end groups of the polyamide. The vinylene epoxy groups are then uniformly dispersed in the polyamide in a relatively unreactive state. Then react vinylene epoxy groups, and a uniform polyamide having a high melt viscosity is obtained. In contrast to it is believed that when a polyepoxy compound having a plurality of vinyl epoxy groups is used, a very rapid one Reaction between the vinyl epoxy groups and the end groups of the polyamide takes place even before these connections are sufficient can be mixed, so that it is not possible to obtain a homogeneous polyamide composition. If on the other hand a polyepoxy compound containing only vinylene epoxy groups is used, it is believed that the reaction with the Polyamide is so slow that the increase in melt viscosity does not proceed smoothly.

The number of vinylene epoxy groups in a polyepoxy compound is limited to 1-3 because it is difficult to be polyfunctional Synthesize epoxy compounds that contain four or more vinylene epoxy groups and such compounds are therefore not industrially useful.

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The thermoplastic linear polyamides to which the method according to the present invention is applicable are polyamides of the amino acid condensation type and, more particularly, polyamides of the type of condensation of dibasic acids with a diamine, and copolymers thereof. Specific examples of suitable thermoplastic linear polyamides are poly-fcj-caprolactam (nylon 6), poly-U> iaurolactarn (nylon 12), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 61O), polyhexamethylene dodecamide (nylon 612), copolymers of C-caprolactam and üj -LauroIactarn (nylon 6-12), mixed polymer of C-caprolactam and hexamethylene adipamide (nylon 6/66), mixed polymer of C-caprolactam and heχamethylene sebacic acid amide (nylon * 6/610), mixed polymer of C-caprolactam, hexamacethylene adipic acid amide and hexamacethylene adipic acid amide eeunid (nylon 6/66/610), mixed polymer of c -caprolactam and hexamethylene terephthalamide (nylon 6 / 6T), mixed polymer of C -caprolactam, hexamethylene terephthalamide and hexamethylene isophthalamide (nylon 6 / 6Τ / 6ΐ, wherein T is a terephthalamide component and I is an isophthalamide component means).

The method of the present invention is applicable to block copolymers of at least two of these polyamides, and a blend thereof with each of the polyamides will be effective for the melt viscosity increases. Polymers of various molecular weights can be used in the present invention will. However, in order to obtain a polymer having a particularly high melt viscosity, it is preferred to use polymers to use relatively high molecular weight, d. H. Polymers

0 0 9 8 3f72 13 0

with a reduced viscosity (measured in a 1% solution in Metjiäcresol at ^v 30 C) of at least 2.0.

The amount of the polyepoxy compound added to the thermoplastic linear polyamide depends on the melt viscosity the starting polyamide and the desired melt viscosity of the crosslinked polyamide compositions. When the viscosity of the starting polymer is 1.0-3 »0 (for a 1% solution in Metjiacresol at 30 C), the polyepoxy compound is normally in an amount of 10-3OO milliequivalents Epoxy groups added per kg of polymer * However, as the optimum melt viscosity range depends on the size, the molding method and the shape of the molded product varies, the amount of polyepoxy compound added can also differ from that mentioned above, in order to obtain an optimal melt viscosity for a special application.

Various methods of mixing the crosslinking agent with the polyamide polymer can be used in the method of the present invention Invention applied. The crosslinking agent can be used with the polymer at any desired stage after completion the polymerization are mixed. Advantageously the crosslinking agent is mixed with the molten polymer removed from the kettle. Another method consists in adding the crosslinking agent to a solid, e.g. pulverized or pelletized, polymer and then to mix the mixture in the melt. In the case of the latter method, the one becomes uniformly dispersed

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and mixed mixture of polyamide and polyepoxy compound heated above its melting point to its melt viscosity to increase.

There is no particular limitation on this method. the Moldings can be made by extrusion, blowing, or compression molding can be obtained from the polymer whose melt viscosity has previously been increased. It is also possible to use the molding in such a way that the melt viscosity is simultaneously during the deformation of the polyamide mass into the molding elevated. Using this technique, a conventional deforming machine can be used. However, in order to achieve as uniform a mixture as possible, it is preferred to use a Dulmadge extruder or a screw extruder.

The conditions for heating and melting vary depending depending on certain factors such as the type of starting polymer and the amount of crosslinking agent used. Therefore it is not possible to give precise values that are suitable for all applications. In general, however, the Increase in 'melt viscosity when deforming the Polyamides run at 200 - 280 ° C within 10 minutes or less, for example 1 to a few minutes, after the polyamide is melted.

There can also be different types of antioxidants, light stabilizers or heat stabilizers or other stabilizers to the composition of polyamide and polyepoxy compound

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binding are added. In addition, pigments, crystallization accelerators and various other types of additives can also be used be admitted. The only limitation is that the additives have no significant adverse effect on the May have a composition of polyamide and polyepoxy compound.

The high melt viscosity polyamidines produced by the method of the present invention using the polyepoxy compounds obtained as crosslinking agents are homogeneous, have a high viscosity stability in the molten state Condition and flow properties necessary for extrusion deformation are particularly suitable.

The following examples serve to further illustrate the invention. All parts and percentages mean parts by weight and percentages by weight and not parts by volume and percentages by volume, unless expressly stated. Unless otherwise specified in the following examples, the measurement of the flow index was carried out using the apparatus described in ASTM D1238-57T at a temperature of 2k5 C and under a load of 2160 G. The solubility was determined according to the following method determined: 1 g of polymer was added to 100 ml of metacresol, and the mixture was heated to 100 ° C. for 60 minutes.

OFiIGINAL 009839/2130

-.13 -

example 1

■ Various types of epoxy compounds have been added to portions of i per kg pellets of nylon 'β Rait a specific viscosity ^ \, _{/ rt} 1.80 - (C = 1.08 / cm 100') obtained by Schmelzsp / C

■ polymerisation was obtained, added in such amounts that

that the epoxy groups became 25 milli-equivalents. After each Mixture had been mixed well, it was done with an extruder with einoc? Screw diameter of 30 mm and an axial

ratio of 20 extruded in the melt and again pelletized

sated. The temperature in the cylinder section and the temperature in the spinneret section of the extruder were both 240 C. Die Results of measured values of the solution viscosity and the melt index of the pellets obtained are shown in Table "I. The products were all completely dissolved in metacresol.

Table I.

Experi
ment No. Epoxy connection 0098 . ■ · - I.
I. Flowing
index "<\ sp
- "TP Soluble
speed 1, ■ "<CT - ^ CH-CH-CH ₀
\ / ³
, 0 8th 2.59. solved 2 3 9/2130 8th 2.61 i
solved 3-, CHoCH-CHCH ₀ CH-CH ₀
³ \ /. ? \ / ²
O "'O 8th. 2.44 solved 4th 7th 2.31 solved A ₀ ^. Ch ₂ -CH-CH-CH-CH ₂ -CH ₂ -
\ ο · ■ .79 - .55;
<> ■ 21st 95

Example 2

Example 1 was repeated except that instead of Polyepoxy compounds according to the invention having a vinyl epoxy group and 1-3 vinylene epoxy groups, polyepoxy compounds having two or more vinyl epoxy groups were used.

When measuring the reduced viscosity and the flow index using exactly the same polyamides as in Example 1 and the polyfunctional epoxy compounds shown in Table II the following results were obtained:

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Table II

Comparative experiment no.

Epoxy compound

Flow index .. fc-.sp C. 41.6 1.85 • 21.5 «,» 3.62 -. ■■ 9.02

solubility

O 2 O IO OO CO 3 CD ^^
ISJ CO CD

. CH, solved

solved

unsolved

partially not resolved

4 * • Η Φ

O Ή

H Φ

• Η «3 Φ • rf H

«Ι.

η φ

• Η Φ ί + »'r4A4> • HO« O -HX) + »ÖH

Φ I «φ • Η tu

Φ * -Ρ

HÄ-P

• Η ο α

Φ Ή ίθ · ** ί? H

00 »Λ

cn

00

O H H Φ

ta c

• Η X! U

φ η

Φ S> β

-H'

CM Π—

• Η Φ X

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It can be seen from the results of Examples 1 and 2 that when a polyepoxy compound having a large number of vinyl epoxy groups was used, the solution viscosity became high, but some of the polymers did not dissolve in metacresol. The extruded material of Example 2 was very uneven, which is believed to be due to the existence of gelled portions. The polymer is unsuitable for deforming.

When corresponding vinylene epoxy compounds were used in place of the above-mentioned vinyl epoxy compounds, this was Increase in melt viscosity only slight, and the resulting Products would be unsuitable to be deformed into shapes.

Example 3

Various amounts of vinyl cyclohexene dioxide became one

■ r

kg pellets of nylon 6 with a viscosity of 1.69 added.

The mixtures were made under the same conditions as in Example 1 treated. The flow index of the resulting high viscosity polyamides is shown in Table III.

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Table III

Quantities τοη vinyl Resultant polyamide cyclohexene dioxide
(*) Flow index solubility O 3.0 solved 5 10.0 solved 7th k, 0 solved 9 1.8 solved 10 1.0 solved

example k

One kg of nylon 6 pellets with a reduced viscosity of 2.39 (C = 1.0 g / 100 cm- *), measured at 30 ° C in metacresol, was with 8 g vinyl yelohexene dioxide {115 milli-equivalents Epoxy groups) and the mixture was heated at 2 ^ 5 C in an extruder with a screw diameter of 30 in the melt mixed. The Pliei index of the pellets obtained (under a load of 5,000 g) at 2 ^ 5 ° C was 0.43 Using these pellets, blow molding was carried out with an extruder having a cylindrical spinneret, The dimensional stability of the extruded product was very good and a uniform thick bottle was obtained.

example 5

One kg of pellets of nylon 6 with a reduced viscosity of 1.6, measured at 30 ° C. in metacresol, was mixed with 12 g of vinylcyelohexene dioxide (170 milli-equivalent epoxy groups). After the latter add; it has been va * _; on the former

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to adhere evenly, the mixture was fed into an extruder ■ with a round spinneret with a diameter of 100 mm brought to perform m a sheet deformation. This gave me a bottle of uniform thickness. The reduced viscosity d ·· molding * was 3 »5 ·

10 kg nylon hit a Fließiradex of 2 ^ ₍ 3 (measured at 230 ° C under a load of 2.160 g) vurdin lit 60 g 1,4-Htxadieneioxid (1.050 Mllli-equivalent epoxy groups) mixed, and the Oeaiseh was mixed with an extruder eit "INEM Sehneckendurchaesser of ^ O MBK extruded in the melt * the flow rate at 230 ° C under a load of 2,160 g was in the obtained pellets, 1 _t 3 · If a tube with a diameter of 30 ami from these pellets by extruding was molded, a uniformly thick tube with good dimensional stability was obtained.

Example 7 -. "'.. ■ _ ..''"'.".. ■. ■"-'---'■

Sin kg pellets of nylon 66 with a flow index of about 60 at 275 C under a load of 2,160 g, -7 g -

Epoxydicyclopentylglycidyl ether (hk milli-equivalent epoxy groups) ashed. The resulting mixture was stirred at 275 ^c ■ it aid a "" extruder "it a diameter of 30 mm in the Sohmelme mixed and then turn pelletleiert * The Schmelsindex dee obtained polymer was under the above conditions, 0.3, and the -Polyeer / Ran completely in

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Dissolve metacreaol. Example 8

With 600 g pellets of nylon 6 used in Example 1 3.4 g of 1,4-cyclohexadlene dioxide (60 milli-equivalent epoxy groups) and 4.2 g of vinylcyclohexene dioxide (60 milli-equivalent) were added Milli-equivalent epoxy groups) mixed, and the mixture was melted and pelletized again under the same conditions as described in Example 1. the However, the temperature of the cylinder section was set to 245 C held. This gave pellets with a melt index of 3.15 (at 2 ^ 5 ° C. under a load of 2,160 g).

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Claims (10)

Claims 1. Process for the production of polyamides with high melt viscosity, characterized in that one is a thermoplastic linear polyamide with an effective amount of a polyepoxy compound for increasing the viscosity a vinyl epoxy group and 1-3 vinylene epoxy groups mixed and reacted in a molten state. 2. The method according to claim 1, characterized in that one the polyepoxy compound is combined, mixed and reacted with the polyamide in a molten state. 3. The method according to claim 1, characterized in that one the thermoplastic linear polyamide in the state of chips or powder mixed with the polyepoxy compound and the resulting mixture is then reacted in the melt. · k. Process according to claims 1-3, characterized in that the thermoplastic linear polyamide used is polyr-ξ-aprolactam, polyhexamethylene adipamide or poly (jJ-laurolac camouflage). 5. The method according to claim 1-4, characterized in that the polyepoxy compound is a compound of the general formula 00 9839/2 13 0 - CH- CH - CH R. - CH - CH m-1 H-CH- R. used, wherein R ₁ and R _{2 are the} same or different and low molecular weight alkylene groups, low molecular weight oxyalkylene groups, cycloalkylene groups, endocycloalkylene groups, alkylenearylene radicals or arylene radicals, R_ a low molecular weight alkyl group 1st and R_ and R "taken together with the carbon atoms of the vinylene epoxy group a 5-membered or 6 -glledrige cycloalkylene group, the sum of the carbon atoms in R ₁ , R_ and R_ is 2-12, η is an integer from 1 to 2, _f m is an integer from 1 to 2 and ρ is an integer from 1-3. 6. The method according to claim 5 »characterized in that one as polyepoxy compound vinylcyclohexene dioxide, epoxydicyclopentylglycidyl ether, 1,4-hexadiene dioxide, 3,4-epoxycyclohexylglycidyl ether, 1,3,6-octatriene trioxide or 2,3,4-tris (2,3-epoxymethyl) phenylglycldyl ether used. 7 * Polyamide with high melt viscosity from a thermoplastic linear polyamide, characterized in that it is a Reaction product of the thermoplastic linear polyamide and an amount of a polyepoxy compound which increases the melt viscosity the general formula 009839/213 0 V " -Jn-I L R ₁ - CH - CH- R; - CH - iet, where R ₁ and R_ are the same or different and low molecular weight alkylene groups, low molecular weight oxyalkylene groups, cycloalkylene groups, endoylcloalkylene groups, alkylenarylene radicals or aryl acid esters mean «R. is a low molecular weight alkyl group and R“ and fi_ also taken together with the carbon atoms of the vinylene epoxy group 5- to 6- membered cycloalkylene group can mean the suane of the carbon atoms in R., R _g and R, 2 - 12, η a whole number from 1 - 2, a an integer τοπ 1-2 and ρ a whole number from T - 3 means. 8. Polyamide _t in NaOH Aacpruch 7 »characterized in that it comprises the polyepoxy compound in an amount corresponding to 10 to 300 milli-equivalents of epoxy groups per g of polyamide. 9. Polyamide according to claim 7 and 8, characterized in that dtfiü al * polyepoxy compound Vinyleyelohexendioxid, Xpoxydicyclopentylglycidylttther _f 1 _e 4-Hexadiendiöxid , 3,4-EpoxyoyclohexylglycidylMther, 1,3,6-Octatrientrioxld and / 2,3, Λ _τ - (2,3-epoxymethyl) -phenylglycldyl ether contains. 10. Polyamide according to claim 7 ** 9, characterized in that es thermoplastic linear polyamide polyhexamethylene adipamide, poly-UJ-lauro-lactarn or poly-C-capro- i.ct «.« twit. O ₀₉₈₃₉ Z ₂₁₃₀