Continuous polymerization process and products therefrom

Details Continuous polymerization process and products therefrom Continuous polymerization process and products therefrom

1998-12-15

2003-05-20

Wilson, D. R. (Department: 1713)

Organic compounds -- part of the class 532-570 series

Organic compounds

Carboxylic acid esters

C525S330300, C525S330600, C525S338000, C525S062000, C525S315000, C525S361000, C525S364000, C525S378000, C525S379000, C525S390000, C525S532000, C525S532000, C525S532000, C526S088000, C526S089000, C526S207000, C526S208000, C526S209000, C526S212000, C526S216000, C526S227000, C526S318000, C526S319000, C526S324000, C526S325000, C526S328000, C526S064000

Reexamination Certificate

active

06566549

ABSTRACT:

This invention relates to a continuous polymerization process and products therefrom. In particular, this invention relates to a high temperature, high pressure, continuous polymerization process to produce oligomers. More particularly, this invention relates to a high temperature, high pressure, continuous polymerization process to produce terminally unsaturated and fully saturated oligomers. “Oligomers,” as used herein and in the appended claims, refers to polymers having a degree of polymerization (“dP”) of less than 50.
The art has long sought an inexpensive, efficient and environmentally sound way to produce low molecular weight polymers. However, production of these low molecular weight polymers has proven to be difficult.
One method of achieving low molecular weight polymers is through the use of efficient chain transfer agents, but this approach has several drawbacks. First, this approach incorporates the structure of the chain transfer agent into the polymer chain. This can be undesirable since that structure will have an increasing effect on the properties of the polymer as molecular weight decreases. Furthermore, the chain transfer agents commonly employed are mercaptans. These materials are expensive and have objectionable odors associated with their presence. Other common chain transfer agents are hypophosphites, bisulfites and alcohols. These also add to the cost of the process, impart functionality to the polymer, may introduce salts into the product, and may necessitate a product separation step.
Another way of lowering the molecular weight of the polymers is by increasing the amount of initiator. This approach adds considerably to the cost of production and may result in polymer chain degradation, crosslinking, and high levels of unreacted initiator remaining in the product. In addition, high levels of initiator may also result in high levels of salt by-products in the polymer mixture which are known to be detrimental to performance in many applications. The same is true for chain stopping agents, such as sodium metabisulfite. Among the preferred free-radical initiators for aqueous polymerization is hydrogen peroxide. It is relatively inexpensive, has low toxicity, and does not produce detrimental salt by-products. However, hydrogen peroxide does not generally decompose efficiently at conventional polymerization temperatures and large amounts must normally be used to generate enough radicals to carry out a polymerization.
High levels of metal ions, alone or together with high levels of initiator, have also been tried as a means for controlling molecular weight. Such an approach is unsuitable for some products that cannot tolerate metal ion contaminants in the polymer product, such as pharmaceutical, medical and electronic applications. In addition, depending on the metal ions used, the product may be discolored due to the presence of the metal ions.
U.S. Pat. Nos. 4,680,352 and 4,694,054 disclose processes for preparing low molecular weight terminally-unsaturated oligomers employing metal chelate chain transfer agents to control molecular weight. These processes suffer from the same problems as those processes employing high level of metal ions, as described above. In addition, because the methods employing the metal chelate chain transfer agents undergo &bgr;-scission reactions, they are limited to producing oligomers having homomethacrylate backbones.
In the
European Polymer Journal
, Volume 8, pages 321-328 (1972), Feit describes a multistep synthesis technique for preparing terminally-unsaturated oligomers and co-oligomers of vinyl monomers having electronegative groups. The process described therein requires a base-catalyzed addition of an acetic acid ester derivative to an activated olefin, followed by hydrolysis of one ester group, followed by a Mannich reaction to introduce a terminal double bond. This three step process is repeated to prepare a terminally-unsaturated oligomer with one additional mer. This process suffers the drawback of being fairly complex, expensive and time-consuming.
U.S. Pat. No. 5,710,227 discloses a high temperature, continuous polymerization process for preparing terminally unsaturated oligomers which are formed from acrylic acid and its salts, and acrylic acid and its salts with other ethylenically unsaturated monomers. The high temperature, continuous polymerization process solves many of the problems associated with previously known methods for preparing terminally-unsaturated oligomers formed from acrylic acid. However, the neat form of many of the acrylic acid products are solid and, thus, require the addition of a solvent to handle and use the products.
U.S. Pat. No. 4,356,288 discloses the preparation of terminally-unsaturated oligomers formed from esters of acrylic acid having a degree of polymerization of about 6-30 by an anionic polymerization reaction carried out in the presence of a catalytic amount of an alkoxide anion. The method is relatively complex. Because the method is inhibited by the presence of moisture (lowering yield and uniformity of the final product), it is not a viable commercial process.
In
Chemical Engineering at Supercritical Fluid Conditions
, pages 515-533 (1983), Metzger et al. disclose the dimerization and trimerization of methyl acrylate in benzene at a pressure of 200 bars and temperatures of 340-420° C. in a flow reactor with a residence time of 5 minutes.
The present invention seeks to overcome the problems associated with the previously known methods for preparing oligomers by providing a polymerization process that is not limited to forming oligomers having only a homomethacrylate backbone or a carboxylic acid-containing monomer residue backbone and that does not require water or other solvent in the manufacture or use of the oligomer. The present invention also provides an oligomer free of metal, salt and surfactant contaminants, that, due to its purity and composition, is not water sensitive or discolored and is liquid when provided neat.
STATEMENT OF THE INVENTION
The invention is directed to a continuous process for preparing terminally-unsaturated and fully saturated oligomers which do not contain, as polymerized units, carboxylic acid-containing monomers, including the steps of:
(1) forming a reaction mixture, substantially free of carboxylic-acid monomers and their salts, containing:
(i) 0.5 to 99.95% by weight of the reaction mixture of at least one ethylenically unsaturated monomer; and
(ii) 0.05 to 25% by weight, based on the weight of the monomer, of at least one free-radical initiator; and
(2) continuously passing the reaction mixture through a heated zone wherein the reaction mixture is maintained at a temperature of at least 150° C. and a pressure of at least 30 bars for from 0.1 seconds to 4 minutes to form terminally-unsaturated oligomers.
In addition, the invention is directed to a process for preparing fully saturated oligomers including the further step of hydrogenating the terminally unsaturated oligomer. The invention is also directed to processes for forming oligomers of vinyl acetate and oligomers of vinyl alcohol.
The process of the invention is useful for preparing oligomers of the formula:
where
A, A
1
and A
2
=
independently selected from —H;
C
1
-C
50
straight-chain or branched alkyl, optionally substituted with a Y group;
C
2
-C
50
straight-chain or branched alkenyl containing 1-5 double bonds, optionally substituted with 1-2 Y groups;
C
5
-C
8
cycloalkyl, C
5
-C
8
cycloalkenyl;
phenyl, (CH
2
)
m
-phenyl, 1- or 2-naphthyl;
—(C═O)H; —C(OR
1
)
2
H;
—(C═O)R
1
, —(C═O)CF
3
; —C(OR
1
)
2
R
1
;
—(C═O)OR, —O(C═O)R
1
; —(C═O)Cl;
—O(C═O)OR
1
; —OR;
—(C═O)NH
2
, —(C═O)NHR
1
, —(C═O)N(R
1
)
2
, —NH(C═O)R
1
, —NH(C═O)H, —(C═O)NH(CH
2
)
m
(NH
3
)
(+)
(X)
(−)
, —(C═O)NH(CH
2
)
m
(NR
1
)
2
;
—Si(OR
1
)
3
, —Si(OR
1
)
2
R
1
, —Si(OR
1
)(R
1
)
2
, —Si(R
1
)
3
;
—F, —Cl, —Br, —I;
—C≡N; oxiranyl;
—NH(C═O)NH
2
, —NH(C═O)NHR
1
,
—NH(C═O)N(R
1
)
2
;
—CH
2
C
n
F
2

Affiliated with

Also associated with

Rating

Continuous polymerization process and products therefrom does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Continuous polymerization process and products therefrom, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Continuous polymerization process and products therefrom will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3038794