CA1198249A - Process for the preparation of a polyamide - Google Patents

Process for the preparation of a polyamide

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Publication number
CA1198249A
CA1198249A CA000419193A CA419193A CA1198249A CA 1198249 A CA1198249 A CA 1198249A CA 000419193 A CA000419193 A CA 000419193A CA 419193 A CA419193 A CA 419193A CA 1198249 A CA1198249 A CA 1198249A
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Canada
Prior art keywords
lactam
nitrile
water
beta
alpha
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
Application number
CA000419193A
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French (fr)
Inventor
Lawrence E. Ball
Mu-Yen M. Wu
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Standard Oil Co
Original Assignee
Standard Oil Co
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Filing date
Publication date
Application filed by Standard Oil Co filed Critical Standard Oil Co
Priority to CA000419193A priority Critical patent/CA1198249A/en
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Abstract

PROCESS FOR THE PREPARATION OF A POLYAMIDE

ABSTRACT OF THE DISCLOSURE
This invention relates to a new process for pre-paring a copolyamide comprising polymerizing an alpha, beta-unsaturated nitrile and water with a molar excess of a lactam. In one embodiment, acrylonitrile, water and capro-lactam are polymerized to form a nylon-3,6.

Description

(5320) PROCESS FOR_THE PREPARATION OF A POLYAMIDE

BACKGROUND OF THE INVENTION
This invention relates to a new process for pre-paring a copolyamide comprising polymerizing an alpha, beta-unsaturated nitrile, water and a lactam.
The preparation of a polyamide from acrylonitrile and water is disclosed in U.S. Patent Nos. 3,629,203 and 3,499,879. The ring opening addition polymerization of caprolactam is also known and is carried out by adding a catalytic amount of water to open the ring and then later removing the water at an elevated temperature. Surprisingly, applicants have discovered that although these polymer~za-tions proceed by different mechanisms the alpha, beta-unsaturated nitrile, water and lactam can be polymerized together to form a copolymer under the appropriate reaction conditions.
The process of this invention results in high yields of a copolyamide which has particularly good physical prop-erties. ~loreover, the percent water insolubility and the structure of the resultant copolyamide can be varied by varying the reaction conditions.

SUMMARY OF THE INVENTION
It has now been discovered that copolyamides can be prepared by a process comprising polymerizing an alpha, beta~
unsaturated nitrile, water and a lactam. More particularly, it has been discovered that a copolyamide containing both three car~on and six carbon carbonamide repeating units can ,0~

(5320) be prepared by polymerizing acrylonitrile and water with a molar excess of caprolactam.

DETAILED DESCRIPTION
The PolYmer The copolyamides obtained by the process ~f this invention are generally defined as containing carbonamide repeating units as follows:
R O H

~(C)n - C - N~ (I) wherein R is a suitable substituent and n is 2-11. Each copolyamide will contain at least two different carbanamide repeating units. Preferred copolyamides are those wherein R
is hydrogen and n is 2 and 5.
The copolyamides of this invention can be poly-merized with other monomers and/or resins. These monomers and/or resins are selected from the group consisting of poly-amides such as nylon-3, nylon-4, nylon-6, nylon-6,6, nylon-6,10, nylon-ll, nylon-12, or monomers thereof such as ammonium acrylate; esters such as methvl acrylate; unsatu-rated acids or salts thereof; and vinyl monomers such flS
acrylamide.
The properties of the copolyamides obtained by the inventive process vary depending upon the amount and identity o~ the monomers u~sed and the reaction conditions. The pre-ferred polyamides are melt processable without decomposition and highly crystalline.
Reactants The inventive process is a copolymerization of an alpha, beta-unsaturated nitrile, water and a lactam.
2.

f~

(5320) Any alpha, beta-unsaturated nitrile can be poly-merized in accordance with this invention. The preferred nitriles contain less than 40 carbon atoms and are repre-sented by the following formula:

, I 1 i 1 C = C - CN (II) Rl wherein each Rl is independently selected from the group consisting of (1) hydrogen; and (2) Cl 30 alkyls.
More preferred nitriles are those wherein each Rl is inde-pendently selected from hydrogen and Cl 4 alkyls. Examples of these nitriles include acrylonitrile and ~ethacrylonitrile.
Any lactam can be used as a comonomer in the instant invention. The preEerred lactams contain less than 40 carbon atoms and can be represented by the following formula:
R

1 2 ~c=o (C)x ¦ (III) I ~ N-H

wherein x is 3 to 11 and wherein each K2 is independently selected from the group consisting of:
(1) hydrogen; and (2) Cl~30 alkyls.
More preferred lactams are those wherein x is 3 to 5 and R2 is hydrogen or a Cl 4 alkyl. Examples of these lactams include caprolactam and pyrrolidone.
This process works best when a molar excess of the lactam is present. Theoretically, all that is needed for the
3.

(5320) polymerization is one mole of lactam per mole of acrylo-nitrile and water. However, it has been found that at equal molar ratios, the copolyamide formed has a low molecular weight a~d takes a long time to form. Therefore, the molar ratio of the nitrile to the lacta~n is preferably less than 1 to 1, more preferably less than 0.~ to 1~
The third monomer component is water. The ratio of the nitrile to the water is preferably about 1 to 1.
Other monomers or polymers can also be polymerized with the nitrile, water and lactam in ths process. For example, ammonium acrylate, a nylon-3 monomer, can be poly-merized with the nitrile and lactam to produce a copolyamide.
Since one mole of water is generated when one mole of ammonium acrylate is polymerized to a polyamide, it is only necessary to add enou~h water so that there is a total of one mole of water, from the ammonium acrylate polymerization and from the added water, for every one mole of the nitrile.
Preferably, the molar ratio of the nitrile to the ammonium acrylate is about 1 to 1, and thus it is not necessary to add any water. In this monomer system, the ratio of the nitrile to the lactam can vary widely and ratios of less than 1 to 1 can be used to prepare copolyamide. It is preferred to use a racio of less than 1 to 2. For the purposes of this inven-tion, any ammonium salt of an alpha, beta-un~saturated car-boxylic acid can be used instead of the ammonium acrylate.
Process Condi~ions The process of this invention can be conducted under a broad range of process conditions. It is important to maintain suitable contact between the mor.omers so that the desired polymerization can occur. Although suitable contact
4.

(5320) time can be established when the monomers are in the solid, liquid or gaseous phase, it is preferred to perform the poly merization in the liquid phase. This liquid phase can be obtained by various methods including the use of solvents.
In the preferred practice of the invention, the monomers are maintained at a temperature above their melting points but below the decomposition temperature of the mono-mers or product polymers, which is generally about 350C.
It is more preferred to conduct this process at a temperature between 125C and 250C, and conducting the process between 150C and 200C is most preferred.
The time required for the instant polymerization process will depend upon various process parameters. For example, at low temperatures it will take longer for the copolyamide to form than at high temperatures. In general, the reaction is conducted in less than 48 hours with times ranging from 8 to 24 hours normally being adequate to produce polymers.
Although the monomers can be polymerized in contact with the atmosphere, a more desirable group of copolyamides hav;n~ high intrinsic viscosities and molecular weights are obtained by carrying out the polymerization in the absence of oxygen. This can be achieved by blanketing the reaction mix-ture with either an inert gas such as nitrogen or with gaseous ammonia.
The instant polymerization can proceed at atmo-sheric, superatmospheric or subatmospheric pressure. Pref-erably, the monomers are heated under superatmospheric pres-sures. It has been found that at pressures such as 0 to
5.

(5320) 5,000 psig are preferable with 50 to 2,000 psig being most preferable.
The polymerization process of this invention can proceed by any of the generally known modes of polymerization including bulk, slurry, suspension or solution polymerization by batch continuous or intermittent addition oE the monomers and other components.
It is often convenient to carry out the instant polymerization in the presence of a diluent which may also be a solvent to the monomers, products or both. Inert diluents which can be used in the process of this invention include hydrocarbons such as benzene, toluene, xylene, ethyl benzene, solvent naphtha, n-hexane, cyclohexane, isooctane and decalin; ether such as dioxane, diethyl ether, dibutyl ether and dimethoxy ethane; aromatic halogenated compounds such as chlorobenzene and dichlorobenzene. In addition to these or~anic solvents, an anhydrous solvent such as liquid ammonia may also be used.
The polymerization conditions have a large effect on the physical properties of the resultant copolyamide. Lower polytnerization temperature, increased polymerization time and catalysts favor the formation of a copolyamide containing higher percenta~es of a carbanamide comprising three carbons.
Increased polymerization time favors formation of higher molecular weighl: copolyamides.
Certain catalysts have been found to be effective in the instant process. Thesè catalysts comprise tertiary amines such as l:ripentylamine and tripropylamine.
Recovery At the end of the polymerization, the unreacted monomers are removed from the reaction mass hy suitable
6.

(5320) means, e.g. distillation, extraction with a solvent or mix-ture of solvents or by combinat;on of such techniques. The unreacted material may be removed in conjunction with removal of low molecular weight polymers, if desired. Any suitable solvent or mixture of solvents may be employed in purifying the crude reaction product. The reaction o~ the solvent is more or less selective. If the polymerization reaction is carried out in the inert or~anic diluent in which the polymer is insoluble, the polymer will precipitate and may be removed by filtration, centifigation, etc. The polymer which is obtained may easily be purified by extracting it with a liquid that is a solvent ~or the monomer but which is not a solvent for the polymer. Frequently, water is used for this purpose.
The polymers produced herein have a wide variety of applications. Generally, they may be used in any application calling for a polyamide. For example, these copolyamides can be used as fibers, plastics, films and molding resins.

SPECIFIC EMBODIMENTS
. .
In order to provide a better understanding of the present invention, the following working examples are pre-sented. In each of the examples, the polymer formed was identified by various analytical techniques as a copolyamide.
Exam~
The monomers, acrylonitrile and water and capro-lactam, were charged into a 1 liter non-stirred autoclave reactor in a molar ratio of 1/1/2. The autoclave was purged with nitrogen for 2 minutes and then pressurized. The poly-merization proceeded for 2 hours at 160C and then for 22
7.

(5320) hours at 210C. The reactor was cooled and opened and the polymer was broken into small pieces and then water extracted for 24 hours. The water insolubility was found to be 42.4%
and the polymer comprised 20% 3-carbon carbonamides and 80% 6 carbon carbonami~es.
Examples 2-The procedure of Example 1 was repeated. The poly-merization conditions and the structure of the resultant copolya~ide is shown in Table I.

Table I
Preparation of Copolyamides React Temp/ Melt Molar Time % H20 Point %
Ex Reactants Ra~io (C/I~r) Insolub (C) Struc.** Crys~al 1 Acrylo/ 1/1/2 160/ 2 42.4 155 20/80 40.30 water/ 210/22 capro-lactam 2 " 1/1/2 140/ 2 22.5 160 24/76 43.1 3 " 1/1/2 189/24 45.3 155 22/78 42.4 4 " 1/1/3 193/24 53.1 165 16/84 42.3 " 1/1/3 160/ 2 60.2 L55 11/89 41.6 6 " 1/1/3 175/24 68.0 155 19/81 42.7 7* " 1/1/2 160/ 2 37.0 145 30/70 43.5
8* " 1/1/3 193/24 55.7 155 26/74 39.6 *Reactor contains 5/O (molar) of tripentylamine based on acrylonitrile concentration.
**Ratio of 3 carbon carbonamides to 6 carbon carbonamides in polymer backbone.

8.

(5320) Example 9 The monomers, i.e. acrylonitrile, ammonium acrYlate and caprolactam, were changed into a 25 ml. glass ampoule in a molar ratio of l/l/3. The ampoule was purged with nitrogen for 30 seconds and sealed with a flame. The ampoule was then placed into a protective metal cage and then the cage con-tainin~ the ampoule was placed in an air oven set at 175C
for 24 hours. The ampoule was cooled and opened and the polymer was broken into small pieces and then water extracted for 24 hours. The water insolubility of this polymer was 30.4/~, the crystallinity was 45.4% and the polymer comprised 32% 3-carbon carbonamides and 68% 6-carbon carbonamides.
Although only a few embodiments of this invention have been specifically described above, it should be appre-ciated that many additions and modifications can be made without departing from the spirit and scope of the invention.
These and all other modifications are intended to be included within the scope of this invention, which is to be limited only by the following claims:
9.

Claims (16)

WE CLAIM:
1. A process for producing a copolyamide com-prising polymerizing an alpha, beta-unsaturated nitrile and water with a molar excess of a lactam.
2. The process of claim 1 wherein the alpha, beta-unsaturated nitrile is acrylonitrile.
3. The process of claim 1 wherein the lactam is caprolactam.
4. The process of claim 1 wherein said process is conducted at a temperature between 150°C and 300°C.
5. The process of claim 1 wherein said process is carried out in the absence of oxygen.
6. The process of claim 1 wherein the ratio of the nitrile to the lactam is less than 0.5 to 1.
7. The process of claim 6 wherein the ratio is less than 0.33 to 1.
8. The process of claim 1 wherein the ratio of the nitrile to the water is about 1 to 1.
9. The process of claim 1 wherein the nitrile has the following formula:

wherein each R1 is independently selected from the group consisting of hydrogen and C1- 4 alkyls.
10. The process of claim 1 wherein the lactam has the following formula:

10 .

wherein each R2 is independently selected from the group consisting of hydrogen and C1-4 alkyls and x is 3 to 11.
11. The process of claim 10 wherein x is 3 to 5.
12. The process of claim 1 wherein the monomers are contacted with a tertiary amine catalyst.
13. A process for producing a copolyamide com-prising polymerizing an ammonium salt of an alpha, beta-unsaturated carboxylic acid and an alpha, beta-unsaturated nitrile with a lactam.
14. The process of claim 13 wherein the ammonium salt is selected from the group consisting of ammonium acry-late and ammonium methacrylate.
15. The process of claim 13 wherein the ratio of the acid to the nitrile is about 1 to 1.
16. The process of claim 13 wherein the ratio of the nitrile to the lactam is less than 1 to 2.

11 .
CA000419193A 1983-01-11 1983-01-11 Process for the preparation of a polyamide Expired CA1198249A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA000419193A CA1198249A (en) 1983-01-11 1983-01-11 Process for the preparation of a polyamide

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA000419193A CA1198249A (en) 1983-01-11 1983-01-11 Process for the preparation of a polyamide

Publications (1)

Publication Number Publication Date
CA1198249A true CA1198249A (en) 1985-12-17

Family

ID=4124306

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000419193A Expired CA1198249A (en) 1983-01-11 1983-01-11 Process for the preparation of a polyamide

Country Status (1)

Country Link
CA (1) CA1198249A (en)

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