CA1109627A - Densification of polypyrrolidone - Google Patents
Densification of polypyrrolidoneInfo
- Publication number
- CA1109627A CA1109627A CA305,295A CA305295A CA1109627A CA 1109627 A CA1109627 A CA 1109627A CA 305295 A CA305295 A CA 305295A CA 1109627 A CA1109627 A CA 1109627A
- Authority
- CA
- Canada
- Prior art keywords
- polypyrrolidone
- water content
- powder
- bulk density
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Artificial Filaments (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method for reducing the water content and improving the bulk density of powdered polypyrrolidone having an initial water content of about 5-60 wt percent which comprises compress-ing said powdered polypyrrolidone at temperatures of 50°C or higher and a pressure of 50 to 300 psi to produce solid polypyr-rolidone, such as kibble, having a dry bulk density of about 20-50 pounds per cubic foot. The product is especially useful as feed for the melt extrusion of polypyrrolidone filaments.
A method for reducing the water content and improving the bulk density of powdered polypyrrolidone having an initial water content of about 5-60 wt percent which comprises compress-ing said powdered polypyrrolidone at temperatures of 50°C or higher and a pressure of 50 to 300 psi to produce solid polypyr-rolidone, such as kibble, having a dry bulk density of about 20-50 pounds per cubic foot. The product is especially useful as feed for the melt extrusion of polypyrrolidone filaments.
Description
l~g~27 BACKGR(~UND OF T~E INVENTION
2 The alkaline-ca alyzed/carDon dioYide bulk polym2riza-
3 tion of 2-pyrrolidone with conversions of 30-40~ or ~ore, is
4 kno~n to produce a hard ~ass which, ~hen chopped, ~ashed and S dried, is suitable for melt-spin~ing into fibers, or other 6 processing (see U.S. 3,721,652). HoweYer, ~he continuous bulk 7 polyoerization of 2-pyrrolidone under agitat~on produces a finely 8 comminuted prcduct vhich is washed vith ~at~r to remove both 9 unreacted no~omer and the alkaline catalyst. The polypyrrolidone prod~ct is then i~ the form of a vet po~der containing about 50 11 veight perce~t ~ater, based on polypyrrolidone. This povder is 12 norually dried, but it has too low a hulk density or economical 13 com-ercial prccesi~g, e.g., it is difficult to feed into an 14 e~truder for melt-spinning into fila~ents. Consequently, ths dry 1~ povder is melt-extruded to for~ dense pqllets vhich are suitable 16 for feeding into ertruders i~ melt-spinning processes. In the 17 process of mel~-eYtruding the polypyrrolidone to form dense 18 pellets, its veight a~erage molecular ~aight is degraded from a 19 high initial value of abou~ 200,000, or ~ore, to a value of 35,000-100,OQO or less, because of the well-k~o~n ter.dancy of 21 nylcn-~ to decoapose into its monomer upon ~elting. U.S.
22 3,814,792 ~ses an alcohol~vater solvent a~ elevated teop6rature 23 to dissolve a polypyrrolidone composition for e~trusion. U.S.
24 3,686,066 discusses the ~olding of solid nylon-~ articlos fro~
vatar-svollen polypyrrolidone contaiLing 100~ or more of ~ater, 26 based on the veight of polypyrrolidone, by applying heat and 27 prsscure to the svoll6n ~ass. U.S. 3,324,061 teaches the us~ of 28 elevated teup6ratures and pressures to dissolve polypyrrolidone 29 in ~ater for dry spinning. It is z~ object of the present in~ention to proYide a means of increasi~g th~ bulk density of 31 polyEyrrolidone vithout substantially degrading its molecular 32 veight.
6~7 BRIEF SUMMARY OF THE INVENTION
A method for reducing the water content and improving the bulk density of finely powdered polypyrrolidone, which com-prises compressing powdered polypyrrolidone, having a water con-tent of about from 5-60% by weight, at a temperature of at least about 50C but below the melting point of polypyrrolidone and a pressure of about from 50 to 300 psi, thereby yielding a solid polypyrrolidone product having a dry bulk density in the range of about from 20-50 pounds per cubic foot.
DESCRIPTION OF PREFERRED EMBODIMENTS
The continuous polymerization of 2-pyrrolidone under agitation, or stirring, produces, at normal conversions, a mixture of finely divided polymer and unreacted monomer. If the mixture is washed and dried, the product is a dry powder which is unsuit-able for further processing because of its low bulk density and concomitant handling and extruder feeding difficulties. In the process of the present invention, the fines are washed with water and dried to reduce the water content of the powdery product to about 5-60 weight percent water, based on the weight of polypyrro-lidone, preferably about 10-40 weight percent water, and most preferably 10-30 weight percent water. This moisture-containing powder is then subjected to compression under sufficient pressure and temperature to produce solid polypyrrolidone having a suitable bulk density for feeding an extruder in a melt-spinning process.
The maximum temperature of the polypyrrolidone during compression is always well below its melting point; consequently, degradation of the polymer to monomer does not occur rapidly. The monomer content of the dried product of this process is normally less than about 0.2 weight percent, which is appreciably better than that obtainable from melt-extrusion pelletizing of the pow-der without further treatment. The temperature selected for the polypyrrolidone during compression is inversely proportional .
1 to its ~ater content. At the lo~sr ~ater conts~ts employed, 2 about 10~, highQr temperatures of about 150C or greater ar~
3 preferred. At the higher ~ater contents employed, about 40~, 4 lo~er temperaturas of 100C or less may be utilized, i.e., e~en as lo~ as about 50C. Generally, maYimUm te~peratures of about 6 75~-225C, preferably about 100-200C, and pressures of 50 psi-7 300 psi are preferred for compression densification of polypyr-8 rolidone in this process. The moisture content of the compressed 9 polymer is generally in the range of 5-40~ by ~eight based on polypyrrolidone. This moisture is removed by drying at 11 temperatures of about 100-15~C, and optionally, under rsducad 12 pressures of a~out 1-5 torr.
13 The polypyrrolidone po~der which rorms the starting 14 material of this process may be any particulate product of polym-erizi~g or copolymerizing 2-pyrrclidons. Preferably 90 weight 16 perce~t of the powder is of screen size greater than about ~o.
17 200 ~0.07 m~) U.S. Standard Sieve and lsss than about ~o. 3 ~6 ~, , 18 on) U.S. Standard Sieve, more pr~ferably No. 40 (0.4 mm)-~o. 10 19 (2 mm) U.S. Standard Sie~s. The product of this process is ~haracterizsd as solid polypyrrolidone having a dry bulk density 21 suitable for melt-spinning, that is, a bulk density of about 20-22 50 lbsfft3, i.e. 20-50 x 0.016 g~cc, or about 0.3-0.8 gfcc, 23 preferably about 30-50 lbs~ft3 a~d most preferably about 40 2~ lbs/ft3. `"Dry bulk der.sity" refers to the bulk density of the solid polypyrrolidone having a water content of less than about 1 26 ~eight percent. The product is obtained as pellets, or kibbles, 27 fro~ a p~llet mill, or as sheets o, films from a 2-roll mill, 28 having any shape or thickness suitable for later comminution, 29 drying and processing. The moisture content of the dried compressed polypyrrolidone ~ill usually ~ less than about 1 31 ~eight percent, pre~erably less than abou~ 0.5 ~sight percent.
;' , 1 Com~osite products, useful for later processing, can be provided 2 by adding materials such as other polyamides, e.g., nylon-6, 3 pigments, vhiteners, e.g., such 2S tita~ium dioxide, anti-4 oxida~ts, ultra-violet sta~ilizers, thermal stabilizers, such as the epoxides, etc., etc., to tha ~et powder bsfore comprsssion.
6 As discussed above, the kibhle prodQct, of the present 7 process, has an improved bulk density ihich facilitates melt 8 extrusion spinning. This improvement also, of course, 9 facilitates melt extr~sion, in ge2eral, regardless of the particular extrusion product. Thus, for eYampls, the present 11 invention also facilitates the melt extrusion of films, sheets, 12 configured articles or, if desired, e~_n diffarent sized or 13 shaped pellets, etc. The kibble product further has vastly 14 improved ganeral handling charact~ristics as compared ~ith the initial poly-2-pyrrolidone powder.
17 Ex_mE~ 1 18 Polypyrrolidone po~der of 170,000 ~eigh~ average 19 molecular ~eight, co4taining 22~ by ~eight of ~ater, ~as compacted by forcing the po~der through the holes of a die of a 21 kibble mill. The size of the holes was 1/8 inch in diameter by 22 1-1/2 inch long. The po~dsr was heated by mechanical mixing, 23 used i~to a hardened cylindrical shaFe and cut into 3/16 inch 2~ lengths at the die holes by a doctor blade. Ki~ble temperatures ~ere about 80C as measured by a thermoms~er in the receiver. A
26 smooth surfaced kibble ~ith irregular ends and 19~ water content 27 was thus formed. The bulk de~sity of the kibble vas 37 lbs/ft3 28 after drying to less than 0.1 weight percen~ ~ater. The 29 molecular weight o the kibble ~as the same as that of 'he polymer powd~r fed to the mill.
ExamPl--2 2 Polypyrrolidone powder or 290,000 wsight average 3 ~olecular weight (10-200 mesh~ coniaining 37 weight parcent wzter 4 (bas~d on polypyrrolidone) was su~jected io compac~ion by passing S it through a 2-roll mill. Roll surface temperature was about 6 148-1~4C. A polymer was compress~d into dense sheets 7 approximately 1/16-3~32 inch thic~ which had 19% ~ater content.
8 The sheats wera chopped into approximately 1/8 inch by 1/8 inch 9 granules and dried. The particle density of these granules was approximately 62 lbs/ft3 and the average bulk density vas about 11 32 lbs/ft3. The ~olec~lar weight of the granules was identical 12 to that of the starting polymer po~der.
22 3,814,792 ~ses an alcohol~vater solvent a~ elevated teop6rature 23 to dissolve a polypyrrolidone composition for e~trusion. U.S.
24 3,686,066 discusses the ~olding of solid nylon-~ articlos fro~
vatar-svollen polypyrrolidone contaiLing 100~ or more of ~ater, 26 based on the veight of polypyrrolidone, by applying heat and 27 prsscure to the svoll6n ~ass. U.S. 3,324,061 teaches the us~ of 28 elevated teup6ratures and pressures to dissolve polypyrrolidone 29 in ~ater for dry spinning. It is z~ object of the present in~ention to proYide a means of increasi~g th~ bulk density of 31 polyEyrrolidone vithout substantially degrading its molecular 32 veight.
6~7 BRIEF SUMMARY OF THE INVENTION
A method for reducing the water content and improving the bulk density of finely powdered polypyrrolidone, which com-prises compressing powdered polypyrrolidone, having a water con-tent of about from 5-60% by weight, at a temperature of at least about 50C but below the melting point of polypyrrolidone and a pressure of about from 50 to 300 psi, thereby yielding a solid polypyrrolidone product having a dry bulk density in the range of about from 20-50 pounds per cubic foot.
DESCRIPTION OF PREFERRED EMBODIMENTS
The continuous polymerization of 2-pyrrolidone under agitation, or stirring, produces, at normal conversions, a mixture of finely divided polymer and unreacted monomer. If the mixture is washed and dried, the product is a dry powder which is unsuit-able for further processing because of its low bulk density and concomitant handling and extruder feeding difficulties. In the process of the present invention, the fines are washed with water and dried to reduce the water content of the powdery product to about 5-60 weight percent water, based on the weight of polypyrro-lidone, preferably about 10-40 weight percent water, and most preferably 10-30 weight percent water. This moisture-containing powder is then subjected to compression under sufficient pressure and temperature to produce solid polypyrrolidone having a suitable bulk density for feeding an extruder in a melt-spinning process.
The maximum temperature of the polypyrrolidone during compression is always well below its melting point; consequently, degradation of the polymer to monomer does not occur rapidly. The monomer content of the dried product of this process is normally less than about 0.2 weight percent, which is appreciably better than that obtainable from melt-extrusion pelletizing of the pow-der without further treatment. The temperature selected for the polypyrrolidone during compression is inversely proportional .
1 to its ~ater content. At the lo~sr ~ater conts~ts employed, 2 about 10~, highQr temperatures of about 150C or greater ar~
3 preferred. At the higher ~ater contents employed, about 40~, 4 lo~er temperaturas of 100C or less may be utilized, i.e., e~en as lo~ as about 50C. Generally, maYimUm te~peratures of about 6 75~-225C, preferably about 100-200C, and pressures of 50 psi-7 300 psi are preferred for compression densification of polypyr-8 rolidone in this process. The moisture content of the compressed 9 polymer is generally in the range of 5-40~ by ~eight based on polypyrrolidone. This moisture is removed by drying at 11 temperatures of about 100-15~C, and optionally, under rsducad 12 pressures of a~out 1-5 torr.
13 The polypyrrolidone po~der which rorms the starting 14 material of this process may be any particulate product of polym-erizi~g or copolymerizing 2-pyrrclidons. Preferably 90 weight 16 perce~t of the powder is of screen size greater than about ~o.
17 200 ~0.07 m~) U.S. Standard Sieve and lsss than about ~o. 3 ~6 ~, , 18 on) U.S. Standard Sieve, more pr~ferably No. 40 (0.4 mm)-~o. 10 19 (2 mm) U.S. Standard Sie~s. The product of this process is ~haracterizsd as solid polypyrrolidone having a dry bulk density 21 suitable for melt-spinning, that is, a bulk density of about 20-22 50 lbsfft3, i.e. 20-50 x 0.016 g~cc, or about 0.3-0.8 gfcc, 23 preferably about 30-50 lbs~ft3 a~d most preferably about 40 2~ lbs/ft3. `"Dry bulk der.sity" refers to the bulk density of the solid polypyrrolidone having a water content of less than about 1 26 ~eight percent. The product is obtained as pellets, or kibbles, 27 fro~ a p~llet mill, or as sheets o, films from a 2-roll mill, 28 having any shape or thickness suitable for later comminution, 29 drying and processing. The moisture content of the dried compressed polypyrrolidone ~ill usually ~ less than about 1 31 ~eight percent, pre~erably less than abou~ 0.5 ~sight percent.
;' , 1 Com~osite products, useful for later processing, can be provided 2 by adding materials such as other polyamides, e.g., nylon-6, 3 pigments, vhiteners, e.g., such 2S tita~ium dioxide, anti-4 oxida~ts, ultra-violet sta~ilizers, thermal stabilizers, such as the epoxides, etc., etc., to tha ~et powder bsfore comprsssion.
6 As discussed above, the kibhle prodQct, of the present 7 process, has an improved bulk density ihich facilitates melt 8 extrusion spinning. This improvement also, of course, 9 facilitates melt extr~sion, in ge2eral, regardless of the particular extrusion product. Thus, for eYampls, the present 11 invention also facilitates the melt extrusion of films, sheets, 12 configured articles or, if desired, e~_n diffarent sized or 13 shaped pellets, etc. The kibble product further has vastly 14 improved ganeral handling charact~ristics as compared ~ith the initial poly-2-pyrrolidone powder.
17 Ex_mE~ 1 18 Polypyrrolidone po~der of 170,000 ~eigh~ average 19 molecular ~eight, co4taining 22~ by ~eight of ~ater, ~as compacted by forcing the po~der through the holes of a die of a 21 kibble mill. The size of the holes was 1/8 inch in diameter by 22 1-1/2 inch long. The po~dsr was heated by mechanical mixing, 23 used i~to a hardened cylindrical shaFe and cut into 3/16 inch 2~ lengths at the die holes by a doctor blade. Ki~ble temperatures ~ere about 80C as measured by a thermoms~er in the receiver. A
26 smooth surfaced kibble ~ith irregular ends and 19~ water content 27 was thus formed. The bulk de~sity of the kibble vas 37 lbs/ft3 28 after drying to less than 0.1 weight percen~ ~ater. The 29 molecular weight o the kibble ~as the same as that of 'he polymer powd~r fed to the mill.
ExamPl--2 2 Polypyrrolidone powder or 290,000 wsight average 3 ~olecular weight (10-200 mesh~ coniaining 37 weight parcent wzter 4 (bas~d on polypyrrolidone) was su~jected io compac~ion by passing S it through a 2-roll mill. Roll surface temperature was about 6 148-1~4C. A polymer was compress~d into dense sheets 7 approximately 1/16-3~32 inch thic~ which had 19% ~ater content.
8 The sheats wera chopped into approximately 1/8 inch by 1/8 inch 9 granules and dried. The particle density of these granules was approximately 62 lbs/ft3 and the average bulk density vas about 11 32 lbs/ft3. The ~olec~lar weight of the granules was identical 12 to that of the starting polymer po~der.
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for reducing the water content and improving the bulk density of finely powdered polypyrrolidone, which com-prises compressing powdered polypyrrolidone, having a water con-tent of about from 5-60% by weight, at a temperature of at least about 50°C but below the melting point of polypyrrolidone and a pressure of about from 50 to 300 psi, thereby yielding a solid polypyrrolidone product having a dry bulk density in the range of about from 20-50 pounds per cubic foot.
2. A method according to claim 1 wherein said powder has a water content of about 10-40 weight percent.
3. A method according to claim 1 wherein said powder has a water content of about 10-30 weight percent and said solid polypyrrolidone has a dry bulk density of about 30-50 pounds per cubic foot.
4. A process of claim 1 wherein said polypyrrolidone powder is compressed at a temperature in the range of about from 75-275°C.
5. A method according to claim 4 wherein said powder has a water content of about 10-40 weight percent, and is compressed at 100°-200°C.
6. A method according to claim 4 wherein said powder has a water content of about 10-30 weight percent and said solid poly-pyrrolidone has a dry bulk density of about 30-50 pounds per cubic foot.
7. The process of claim 1 wherein said polypyrrolidone powder has a particle size in the range of about from United States standard sieve No. 200 to No. 3.
8. A method according to claim 7 wherein said powder has a water content of about 10-40 weight percent.
9. A method according to claim 7 wherein said powder has a water content of about 10-30 weight percent and said solid poly-pyrrolidone has a dry bulk density of about 30-50 pounds per cubic foot.
10. The process of claim 1 wherein said polypyrrolidone powder is compressed by extrusion through a kibble die mill thereby yielding a kibble product.
11. A method of melt spinning powdered pyrrolidone having an initial water content in the range of about from 5 to 60 per-cent, by weight, based on the weight of polypyrrolidone, which comprises the steps of:
(a) compressing said polypyrrolidone at a temperature of at least 50°C but below the melting point of polypyrrolidone and a pressure of about from 50 to 300 psi thereby yielding a solid polypyrrolidone product having a bulk density in the range of about from 20-50 pounds per cubic foot;
(b) drying said polypyrrolidone product of step (a) to reduce the water content thereof to about from 0.5 to 1 percent, by weight, based on the weight of said polypyrrolidone; and (c) feeding said dried polypyrrolidone to a melt spin-ning extruder and melt extruding said polypyrrolidone into fila-ments.
(a) compressing said polypyrrolidone at a temperature of at least 50°C but below the melting point of polypyrrolidone and a pressure of about from 50 to 300 psi thereby yielding a solid polypyrrolidone product having a bulk density in the range of about from 20-50 pounds per cubic foot;
(b) drying said polypyrrolidone product of step (a) to reduce the water content thereof to about from 0.5 to 1 percent, by weight, based on the weight of said polypyrrolidone; and (c) feeding said dried polypyrrolidone to a melt spin-ning extruder and melt extruding said polypyrrolidone into fila-ments.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA305,295A CA1109627A (en) | 1978-06-12 | 1978-06-12 | Densification of polypyrrolidone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA305,295A CA1109627A (en) | 1978-06-12 | 1978-06-12 | Densification of polypyrrolidone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1109627A true CA1109627A (en) | 1981-09-29 |
Family
ID=4111675
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA305,295A Expired CA1109627A (en) | 1978-06-12 | 1978-06-12 | Densification of polypyrrolidone |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1109627A (en) |
-
1978
- 1978-06-12 CA CA305,295A patent/CA1109627A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0175769B1 (en) | Polyethylene molding composition and process | |
| US6136097A (en) | Process for producing thermoplastic starch | |
| JP2617188B2 (en) | Manufacturing method of high molecular weight polyamide | |
| US6375881B1 (en) | Process for making a plastic material | |
| US20030228454A1 (en) | Cellulose fiber reinforced composites having reduced discoloration and improved dispersion and associated methods of manufacture | |
| KR101584650B1 (en) | Method for producing a polymer material filled with long fibers | |
| CA2178036A1 (en) | Advanced compatible polymer wood fiber composite | |
| AU1693497A (en) | Advanced engineering resin and wood fiber composite | |
| GB2262527A (en) | Process for grinding cellulose compounds | |
| GB2032933A (en) | Process for the regeneration of polymers from waste | |
| US4130521A (en) | Densification of polypyrrolidone | |
| CA1109627A (en) | Densification of polypyrrolidone | |
| EP0427339B1 (en) | Process and composition for manufacturing friable rubber bales | |
| SE429799B (en) | filtration process | |
| US5523372A (en) | Starch graft copolymer from prime starch | |
| WO1994026491A1 (en) | Moulding composition | |
| WO2004058480A1 (en) | Process for producing bales of amorphous and semi-crystalline polyolefins and bales produced thereby | |
| GB2023621A (en) | Densification of Polypyrrolidone | |
| EP0050039B1 (en) | Elastomeric composition and process for producing the same | |
| KR101208107B1 (en) | Manufacturing method of plastic for car interior material using biomass pellet and thereof | |
| JP2001234493A (en) | Method for producing dry pulp or pulp resin composite material and device for producing the same | |
| GB2244059A (en) | Cellulosic product, process for the production thereof and uses thereof | |
| DE2528563A1 (en) | THERMOPLASTIC FILLING COMPOUNDS, PROCESS FOR THE PRODUCTION OF THE SAME AND PLASTIC COMPOUNDS WITH A CONTENT ON YOU | |
| US4752429A (en) | Process of shaping thermoplastic material containing a carbohydrate additive | |
| AU5400690A (en) | Cellulosic product, process for the production thereof and uses thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |