SE423241B - PROCEDURE FOR PREPARING A POLYAMIDE SEGMENT POLYMER - Google Patents

Description

30 25 35 '35 bar of polyamide as starting components. One polyamide, said segment being bonded to another segment derived from the other polyamide and having a molecular weight of e.g. 200. Because it has not been possible to control or regulate where the amide exchange or reaction would take place, other methods have been proposed. U.S. Pat. No. 3,685 O7 proposes the use of two different low molecular weight polyamides, i.e. in the range 1000-H0O0. ' The polyamides are partly different in that one is an amino-terminated polyamide, while the other is a carboxyl-terminated polyamide. The other difference is that the remainder of the polyamides are also different. The above-mentioned disparate polyamides are copolymerized at a temperature where the amide exchange or transamidation is insignificant, while the reaction between amino-terminated groups with carboxyl-terminated groups is practically complete. The product formed is a block polymer in which the blocks have substantially the same molecular weight as the starting polyamide, i.e., 1000-10000.

The above methods require separate production of the article and one of the starting components followed by remelting and blending to produce a block polymer. This is a disadvantage. f In contrast to what one could on the basis of the prior art. It has now been found that a polyamide block polymer can be formed using a prepolyamide salt and a melt spinner. The separate preparation of one of the starting polyamides can thus be excluded, as can its remelting. av pglgamidçp_kag; u§e- aslutas. The need for heating can therefore be reduced to a minimum in the present procedure. In the process of the present invention, the salt and the polyamide are mixed at a temperature ranging from the melting point of the highest melting component to below the amide exchange temperature for a mixture of the melt-spinnable polyamide and the homopolymer which would result from a polymerization. The mixing at the elevated temperature is continued until substantially all of the salt and all of the polyamide have been converted to a block polymer. In the first step, a dry salt of the prepolyamides can be mixed either with dry particles of the melt-spinnable polyamide or The resulting block polymer can be transferred to a fiber or monofilament yarn, which in turn can be processed into, for example, a yarn or a fabric. The invention is further illustrated in connection with the accompanying figure, which presents generalized curves for different types of polyamides, which have been obtained by fractional precipitation from The curves approximately represent the data given In general, the curves illustrate the fact of formic acid. in the example. that different types of polyamides can be differentiated by means of fractional precipitation from formic acid.

One of the components used as a starting material in the present process is a salt selected from the group consisting of prepolyamides of the following formula: RRRR 0 O: k + _11 n- (NH 3 -CH 2 -? - 9-O-Ru -OY - 9-CH 2 -H 3 N) (OC-R 5 -CO) 1 H RB RB H wherein R 1, R 2 and H 5 are selected from H, C 1 -C 10 alkyl and C 5 -C 10 isoalkyl; .

Ru is selected from C 1 -C 10 alkylene and C 3 -C 10 isoalkylene; and R 5 is selected from C 6 -C 10 arylene, C 0 -C 10 alkylene and C 3 -C 10 isoalkylene.

The above-mentioned solid salt can be referred to as a prepolyamide, since the salt loses water when heated under suitable conditions. forms a bond ~ -c- so as to form a polyamide- H II O The second component used as a starting material in the process of the invention is a melt-spinnable polyamide. As the term "melt-spinnable polyamide" is used in the present case, it is not intended to include the polyamide which could be formed from the above-mentioned prepolyamide salt. Melt spinning refers to a process in which the polymer, a polyamide, is heated to a temperature in excess of its melting temperature and in the molten state it is forced through a spinning nozzle. This nozzle consists of a plate containing from one to several thousand orifices, through which the molten polymer is forced under pressure. The molten polymer is a continuous fiber yarn, and depending on the number of openings, many fiber yarns can be formed simultaneously. The molten fiber threads are subjected to cooling so that they solidify and join and collect on a bobbin. This technique is described in more detail in ENCYCLOPEDIA or POLYMER SCIENCE AND TEGHNOLOGY, vo1.i8, Manèmaae Fibers, Manufacture.

In Polyamides which are crystallizable and which reach a difference of at least BOOC between melting point and the temperature at which the molten polymer undergoes decomposition, melt-spinning can be melt-spun. Examples of melt-spinnable polyamides are the following: nylon-6,6 (also known as polyhexamethylene adipamide), nylon-6,10 (polyhexamethylene enecabamide), nylon-6 (polypentamethylene carbonamide), nylon-11 (polydexamethylene carbonamide), MXD-6 ( polymetaxylylenadipamide), PACM-9 (bis (paraminocyclohexyl) methanazelamide), PACM-10 (bis (paraminocyclohexyl) methanesbacamide), and PÄCM-12 (bis (paramínocyclohexyl) methandodecanoamide); others are listed in ENCYCLOPEDIA OF POLYMERS SCIENCE AND TECHNOLOGY, V01. 10, In the section "Polyamide Fibers", table 12. Methods for producing these polyamides are well known and are described in a number of patent and professional journals. The amount of salt present relative to the amount of melt-spinnable polyamide can vary over a wide range. However, if too much of either of the components is used, the resulting copolymer will not be a block polymer. Rather, it becomes a copolymer, which consists for the most part of long chains of the predominant component bridged together by means of relatively short segments of the component used in a smaller proportion arranged in a statistically random manner. Differences between a random copolymer and a block polymer can be demonstrated by comparing the physical properties of the two polymers. In the present invention, a useful range in terms of the amount of salt calculated on the total weight of the components is between about 10% by weight. and about 75% by weight, with the range from about 20% by weight to about H0% by weight being preferred. In the process of the present invention, the pre-polyamide salt is mixed with the melt-spinnable polyamide. If the polyamide is used in the molten state, it is prepared by heating it to a temperature above its melting point but below its decomposition temperature. "This heating is carried out in an inert atmosphere. The resulting mixture is then heated in an inert atmosphere, e.g. nitrogen, carbon dioxide, etc. The temperature to which it is heated is in the range from the melting point of the melting component of the mixture at the highest temperature to a temperature below about the amide yield temperature of a mixture of The lower temperature is defined by the melting point of either the melt-spinnable polyamide or the salt, whichever is higher.The upper temperature of the process is an amide exchange temperature. In this process, one of the polyamides which could undergo such exchange is the melting point include the polyamide. The second material would be a polyamide formed from the prepolyamide salt.

Thus, if the latter polyamide were formed and mixed with the melt-spinnable polyamide, the present would be a temperature below which amide exchange would not take place between the two or this exchange would be so small that a block polymer was not formed. Amide exchange refers to the reaction in which a group É _N_C- u O in a polyamide (designated A in the illustration below) reacts with another polyamide (designated B in the illustration below), so that the following reaction scheme becomes representative of the final result: * ll l * ll ANCA ÅfN C ~ Å - + l I BCNB BC NB ~ ll l ll l OHOH Amide exchange is the mechanism by which a block polymer is formed by a process known as melt blending.

The heated mixture of the salt and the melt-spinnable polyamide is mixed within the above-mentioned temperature range and under an inert atmosphere. The mixing at elevated temperature is continued until substantially all of the salt and all of the polyamide have been converted to a block polymer. Samples of the mixture can be taken during processing and tested to determine when the conversion is essentially complete. One of these test methods is described in the examples.

When substantially all of the salt and all of the polyamide have been converted into a block polymer, the resulting copolymer can be represented by the following structure: in the interconnection of the groups -ñ- and / or Ig ~ 77f2ss9-9 6 _ _ (divalent) e H Éläz -âläâ É f (radical) (-N-CH 'cCoR -oc- -CH -N-cèa ~ c-)' iav §malt '+ 7 2' | - | H I f 2 H '5 H n (spinable) -HfR3 RÉH _ o o (p? LYam1d) m where the different symbols R have the previously stated meaning. The symbols n and m refer to the relative amounts of groups present. H (100) is between about 10% by weight, and the percentage is about 75% by weight for the useful range. Insignificant amounts of unreacted salt or melt-spinnable polyamide may remain, but the effect thereof on the properties of the resulting segment polymer should be negligible. Furthermore, any unreacted component can be converted during the further processing of the block polymer, e.g. upon transfer to a fiber. Any unreacted component can of course also be removed in various ways.

As can be seen from the previously stated structural formula for the block polymer, the melt-spinnable polyamide is present in the form of the divalent radical. -This divalent radical arises through I in the melt spin- 0 H>. only the polyamide.with the groups_ -R5- fi- OH and / or -CH2-k-H_i.salt. The following examples describe how certain polyamide block polymers were prepared using the process of the invention. For the purpose of comparison, block polymers are also described. similar polyamides produced by other means. in addition with polyamides and polyamide random copolymers.

EXAMPLE 'A salt having the following structural formula: O g _ - + +' - ä H 'p [NH3 (cH2) 3-o- (cH2) 2-o- (cH2) 3NH3] _ [o - (cH2) uc- 0] which may be called 30203-6 ~ sa1t, was used as one component and * was prepared in the following manner. First, 1,2-bis (β-cyanoethoxyethane) was prepared, which has the following structural formula: NC- (CH2) 2-Q- (CH2) 2-O- (CH2) 2-CN. To prepare it, 930 grams (15 moles) of ethylene glycol and ü5.6 grams of an NO% aqueous solution of KOH were charged to a 5-liter double-walled glass reactor (for water cooling) and equipped with a bottom outlet and shut-off valve. Acrylic nitrile (NC-CH = CH2) in an amount of 1620 grams (30.6 moles) was then added dropwise with stirring at such a rate that the temperature was kept below 3500.

After the addition was complete, the mixture was stirred for a further 1 hour, after which it was left to stand overnight. batch of 6 molar HCl.

The mixture was neutralized to a pH of 7 by adding. After washing with a saturated NaCl solution three times, the product was separated from the aqueous layer, then dried over CaCl 2 and passed through an Al 2 O 3 column to ensure that all basic material was removed.

(NH2 (OHH) 3-o- (eng) 2-o- (cH2) 3NH2).

The yield was 90% of theory.

The next step involved the preparation of H, 7-dioxadecamethylenediamine. In an 800 ml hydrogenation reactor, 150 grams of 1,2-bis (β-cyanoethoxyethane), 230 ml of dioxane and about 50 grams of Raney-Co were charged. with hydrogen up to lü0 kg / omg and heated to 11000.

The reactor was freed from air and pressurized. When the hydrogen was consumed, additional hydrogen was added until the pressure remained constant. was filtered.

During cooling, the pressure was relieved, and the catalyst Dioxane was removed by atmospheric distillation.

The remaining mixture was distilled using a distillation unit with a 0.9 m spinning belt. at 123-12400 and 3.75 mm Hg. purity of 99.95% was obtained.

Diamine distilled About 98 grams of a material with a The formed material is called diamine 30205.

In the next step, the salt was prepared. To a solution of ul, 50 grams of adipic acid, which was dissolved in a mixture of 250 ml of isopropanol and 50 ml of ethanol, was added with stirring 50 grams of the diamine 30203 dissolved in 200 ml of isopropanol.

Upon cooling, a polymer salt crystallized out of solution.

An exothermic reaction occurred.

The salt was collected on a Büchner funnel and then recrystallized from a mixture of H00 ml of ethanol and 300 ml of isopropanol solution.

The product, which was dried in vacuo overnight at 6000, had a melting point of 127-12800 and the pH of a 1% solution was 6.9. 85 grams (92% yield of theory) of the salt were obtained. a) The block polymer was prepared in the following manner 17.1 grams of dry 30203-6 salt and H0 grams of dry, finely divided nylon-6 were mixed in the dry state in a suitable container using a cylinder for a ball mill. The resulting mixture was then charged to a vessel equipped with a stirrer. The vessel and its contents were purged with dry nitrogen, the method being described as follows: 1712559-9 then in a steam bath maintained at 24500 and under a positive nitrogen pressure. Once the mixture had reached a molten state, it was stirred for 1 hour. After cooling, the resulting block polymer was analyzed for structure; b) A suitable container was purged with dry nitrogen and while being kept under nitrogen was added 40 grams of dry powdered in This nylon-6 was a commercially available material. The container and its contents were heated to 24506 using a steam bath. The material used nylon-6 began to melt at 210 ° C. To the molten material nylon-6 was added 1.7 grams of the previously prepared 30203-6 salt.

While the salt was added, the container was kept under a positive nitrogen pressure and during and after the addition the formed mixture was stirred continuously. The container and its contents were kept at a temperature of 2-5 ° C for 1 hour. After cooling, the polymer formed was analyzed for structure. nylon-6.

The method used to analyze the polymer structure; included fractional precipitation of the polymer in formic acid. Generally, one gram of dry polymer (copolymer, slum or block polymer, or homopolymer) was weighed to an accuracy of one tenth of a milligram. This one gram sample was dissolved in standardized formic acid (ie 90% formic acid). The resulting solution was diluted with distilled water to a given percentage of formic acid, trex. 557. The solution was allowed to stand at room temperature for 5 hours and then filtered. The mixture was washed with water, dried and weighed to determine the precipitate percentage collected at this particular formic acid concentration.

A curve was then plotted by depositing percent recovered material against the formic acid concentration. The different polymers¿ ie. The slip polymer, the block polymer, the homopolymer (eg nylon-6), all have different solubilities in formic acid. ' Each type of polymer thus gave a characteristic curve.

Table I shows how much material was recovered for nylon-6, polymerized 30203-6 salt and a physical mixture of equal amounts of nylon-6 and 30203-6 salt and segment-30203-6 // 6 polymer prepared by melt mixing; and random 30203-6 / 6 copolymer. For the mixture, calculated values are also given based on what the expected values would be based on the curves of the recovered material of the various polymers. Table II contains data regarding LIÛVIIII net materials for four 30303-6 // 6-block polymers prepared by melt blending and four block-50205-6 // 6 polymers prepared by the process of the present invention.

TABLE II Precipitation of various block polyamides in formic acid. % formic acid% recovered material _. E i örel 'ande äïfäàëi: ššaššzšvë ning ^ 3 0 5 6 7 8 _9_ 10 55 58.5 0 0 0 O 0 OO 50 75.2 55.1 0 0 2.7 0 90.5 9.5 97 82, 9 69.9 20.7 0.9 39.1 35.3 67.1 52.0 .00 86.5 80.7 58.7 6.7 60.3 70.7 70.2 77.5 01 87 .9 xx 77.7 62.2 79.5 82.2 81.8 80.6 38 88.5 89.9 85.2 72.5 82.9 - 80.2 88.7 35 ~ 88.9 92 .2 88.5 79.2 85.8 89.0 85.9 xx 32 89.5 93.1 89.5 82.5 88.11 91.6 88.1 90.5 29 90.0 93.5 90.5 86.1 88.5 92.3 88.0 93.0 25 90.7 93.5 91.6 xx 90.1 95.0 89.5 93.5 23 89.3 90.0 xx xx 90.6 93.1 90.3 90.0 20 90.1 90.5 93.3 87.6 90.6 90.9 90.3 xx x Samples prepared by melt blending 70% nylon-6 and 30% 30283 -6 polymer. Samples 5, 0, 5 and 6 were melt blended at 283 DEG C. for 15, 60, 180 and 360 minutes. - xx Indicates that a sample was taken, but the result may be assumed to be incorrect.

+ Samples prepared using 70% nylon-6 and 30% 30203-6-Salt. 7712559-9 10 .umHuxmHwM mmm> mwucm hmm »m» muH§mm fi: mä «mwov> ohm 1 _ 1 xx m \\ w1moNom1u: øEwmm zoo u1moNon om% mmHhwEmHoQ« m1 fl oH> n> m Hnoon m> wwn : wmummn.wGHQ ©: mHm x _ Emhw H mm ummwwmn mm N> onQ cmomå »Emhw.N mm uuhmmmn H> ohm + _ _ wGHmxhmEn <1 o.Hw m.mæ o.mæ xx 1 1 N 1 oáo fl oo oäo fi oo 1 1 m 1 imo oáo ä? ä 1 1 3 1 N13 mio ïoo ïo 1 1 mH ommo mšo oäo io. 1 1 1 oN m Hw 1 1 1 1 1 1 mN 1 w.Nm æ.mm 1 1 1 1 mN fo »1 1 1 1 1 1 oN H32. 1 1 1 1 1 1 om 1 1 1 o o: do iom om Nomm I 1 1 I I 1 Nm. 1 1% Náo 1 1 1 1 mn w mN 1 1 1 1 1 1 mm 1 H.Hm z1Hm 1 1 1 1 oz »ÄH 1 1 1 1 1 1 S Hqm 1 1 1 1 1 1 =: 1 o fl šämm 1 1 imo QS m: .io 1 1 1 1 1 1 to N fl o Nnwm Mon .1 1 ma? mom om _ o m.Hm H.mm 1. 1 N.Nm 1 mm 1 1 1 1 1 imo om 1 1 1 1 o 1 R oo 1 1 oo om umcxmhmm_ »mnw> nmm @ o_ 1 NHNH 1 _ 1 hm HEmzHoQ m m1momqm nmE> Hom% mww% m% MR > wøw fl wsø: mHm fl 1ømnmmHLwEnHom + m CoHhz Hm fi hmumë pmQcs> ps w mmæmnaë w .n .mnmmäaä. nmoHEmmHom mxHHo wa wcHcHHmmpD H .AQ fi m 10 15 20 25 30 _nentpolymers 7712559-9 ll _ Both the data given in Table I and the representative curve (curve A) in the figure show that practically all nylon-6 is recovered when the percentage of formic acid is reduced about 55-56%. In contrast, for the polymerized 30203-6 salt, which is represented by curve F, no precipitation of the polyamide takes place until the formic acid concentration drops to about 15%. Data for the polymerized salt are shown in Table I.

From the data given in Table I and from the representative curve (curve D) in the figure, it further appears that the precipitation of a random. 30203-6 / 6 copolymer does not occur until an approximately H5% concentration of formic acid is reached. Unlike nylon-6; which has a practically vertical recovery curve (with the exception of the upper part) ¿it also applies that the recovery curve for the random copolyamide has a more gradual transient slope.

The DSC (differential scanning calorimeter) curves for toughness produced by the present process showed the absence of endothermic peaks, which correspond to the melting of either 30203-6 salt or 30203-6 polymer. Furthermore, the block polymer produced by the present process exhibited endothermic peaks similar to those exhibited from 50203-6 // 6 block polymers prepared by melt blending. Finally, the block polymers had melting points that by more than 100 ° C exceeded the value observed for a random copolymer with the same total composition. This comparison thus showed that polyamide block polymers can be prepared according to the present invention.

Some of the above polymers were also characterized by means of DSC melting point. In particular, melting points were obtained for nylon-6, random polymer 30205-6 / 6 and 30205-6 // 6-block polymers prepared according to the invention. DSC values and intrinsic viscosity values are given in Table III. 10 15 20 25 30 835 7112559-9, 12 g TABLE III Physical constants 8 Equipment i 'I Dsc ^ 90 Inner Start at Peak Value Xššëgålågï at Nylon-6 e e'21o 222 ai, o3 _Slump polymer 30203-6 / 6, 138 j 161 '* g 0.81 Segment polymer' I 30203-6 // 6 'Sample 7. _ l86 207 0.86 Sample 8 ~ 193 208 0.78 Prev 9 W 198 213 io, 6o Sample 10 193 - 210 _ 0, 85 7 Differences between polymers in terms of melting temperatures reflect differences in segment sizes, while differences in viscosity reflect differences in molecular weight.

Recovery curve E represents what happens when a mechanical mixture of nylon-6, polymerized 30203-6 salt and block polymer 3Q203-6116 precipitates from a solution in formic acid. The recovery data actually measured for the mixture are almost equivalent to a calculated recovered amount, based on actual recovery data for the individual polymers, taking into account the amount of each polymer used to produce the mechanical polymer. the mixture. Actual recovery data and calculated values reported in tebeii 1. g 'In general, the above comparison between the different recovery curves for the different polyamides shows that the different polymers can be characterized by their solubility in formic acid.

* Table II contains data for four different 30203-6 // 6-segment polymers. Said polymers, i.e. Samples 3, A, 5 and 6 were prepared by melt blending nylon-6 and 30203-6 polymer for varying periods of time. Table II also contains recovery data for four 3020} ~ 6 [/ 6-block polymers¿ namely samples 7, 8, 9_Qçh 10, * prepared according to the present invention.

A comparison of the recovery curves of 30205-6 // 6 copolymers prepared by melt blending with those of the polymers of the present invention shows that the process of the present invention results in a block polymer. The recovery curves are represented by curves B and C in the figure. Curve B represents a composite recovery curve for 30203-6 // 6-segment polymer prepared by melt blending 30203-6 polyamide and nylon-6 at 28200 for about 2-3 hours. Curve C represents the recovery curve for a block polymer prepared in accordance with the present invention. The small difference between curves B and C is assumed to represent an experimental difference rather than a difference in structure. A change in the processes for either or both segm fl mpohmen fl could change the percentage yield. Support for this assumption is found in the fact that other block polymers prepared according to the present invention have recovery curves which were to the left of curve B. Results which are analogous to those mentioned above are obtained when salts other than a 30205-6 salt, e.g. BQÄOB-6, 50603-8 and 30105-14, an- Similar results are also obtained when other temperatures an- Similarly, similar results are obtained if another group of CO-C10-alkylene or a C3-C10-isoalkylene or is reversed. turned. a C6-C14 arylene was used instead of the tetramethylene (H5) used in the example. Examples of said C 0 -C 10 alkylenes and C 3 -C 10 isoalkylenes are ethylene, trimethylene, isopropylidene, isobutylidene and the like. tolylene and the like. The listed C 1 -C 10 alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl and decyl, and the use of such groups in place of the hydrogen used in R1, R2 and RB in the example together with isoalkyl groups Correspondingly, Examples of said C6-C11 arylenes are naphthylene, phenylene, also gives similar results. The addition of any of the above alkylene or isoalkylene groups instead of the ethylene group used in Ru in the example also gives similar results.

Claims (10)

7712ss9 + 9 H lä _ PATENTKHAV. _ 1. A process for producing a polyamide sealant, characterized in that:. (a) mixing a melt-spinnable polyamide and a salt selected from the group consisting of prepolyamides of the formula: - H H H R 1 2 2 1. - (NHB-cua- (š - po-Ru-o-É: - clx-CHQ-Hšïv) (oc-Rs-c HH 1-13 * g: <3 H wherein A H1, H2 and RB are selected from H, C1-C10-alkyl groups and C5-C10-isoalkyl groups; Hu is selected from C1-C10-alkylene groups and C3-C10-isoalkylene groups; and '5 H5 is selected from the group consisting of C6-C10-arylene groups, C0-Cl0 7 alkylene groups and C3-C10 isoalkylene groups; wherein the salinity is between about 10% by weight and about 75% by weight of the total weight, I (D) in an inert atmosphere heats the resulting mixture of the salt t and the polyamide to a temperature in the range from the melting point 'of the component melting at the highest temperature to x below about the amide exchange temperature for a mixture of the melt-spinnable polyamide and a polyamide which would arise g in polymerizing the salt, and I (c) mixing the heated mixture at said temperature and 'in the inert atmosphere, until substantially all of the salt and all of the polyamide have been converted to polyamide block poly lakes. 2. A process according to claim 1, characterized in that the salinity amounts to from about 20% by weight to about H0% by weight of the total weight. H c 3. A method according to claim 1 or 2, characterized in that H1, H2 and H3 are H. '"Ä. 4. A process according to claim 3, characterized in that Ru is a C2-alkylene group. _ A method according to claim 4, characterized in that an H5 is enfïsfêfßflfiïëå fi vpv-N, 7712559- 9 15 Process according to any one of the preceding claims, characterized in that a temperature of about 2ü5 ° C was maintained during the mixing in step (c). ' A process according to any one of the preceding claims, characterized in that in step (a) dry particles of the melt-spinnable polyamide and a dry salt of the prepolyamides are mixed. k ä n n e t e c k- k ä n- A process according to any one of claims 1 to 6, comprising in step (a) mixing the melt-spinnable polyamide in the molten state with a dry salt of the prepolyamides. 9. A process according to claim 8, characterized in that the mixture in step (a) is carried out in an inert atmosphere. 10. A process according to claim 9, characterized in that the heating in step (b) is carried out while mixing the resulting mixture. REQUIRED PUBLICATIONS: