Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-04-24
2001-04-17
Teskin, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S079000, C526S173000, C526S181000, C526S313000, C526S328000, C526S328500, C526S335000, C526S340000, C526S346000, C526S347000, C525S328900, C525S355000
Reexamination Certificate
active
06218485
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing a monodisperse polymer and, more specifically, to a process for producing on an industrial scale a monodisperse polymer having a controlled molecular weight and a controlled molecular weight distribution by living anionic polymerization.
2. Description of the Related Art
It has been known for a long time that polymers having a controlled structure are obtained from conjugated dienes, vinyl aromatic compounds and (meth)acrylic acid esters by living anionic polymerization using an alkali metal or organic alkali metal.
It has also been known that an alkenylphenol polymer typically represented by p-vinylphenol is useful as a resist material, a curing agent for epoxy resins, an antioxidant and the like.
As for processes for producing alkenylphenol polymers, several processes have been proposed including: thermal radical polymerizations to give a polymer of p-vinylphenol (JP-A 53-13694, JP-A 57-44067, JP-A 57-44608, JP-A 57-44609, and JP-B 61-2683); radical polymerization of a p-vinylphenol wherein the hydroxyl group of p-vinylphenol is protected by a saturated aliphatic protecting group and a treatment with an acidic reagent follows to give a polymer of p-vinylphenol (JP-A 4-279608 and 6-298862); and an anionic polymerization of p-vinylphenol wherein the hydroxyl group of p-vinylphenol is protected by tert-butyl dimethyl silyl group and a treatment with an acidic reagent follows to give a polymer of p-vinylphenol having a sharp molecular-weight distribution [Yuki-Gosei Kagaku 44, 2, 45 (1986)]. Further, the present inventors have proposed the homopolymerization or the copolymerization of alkenylphenol wherein the hydroxyl group of alkenylphenol is protected by a saturated aliphatic protecting group and detachment of the protecting group follows to give a narrow polydispersity polymer of alkenylphenol (JP -A 3-277608 and 4-53807).
The living anionic polymerization is suitable for the synthesis of a polymer such as an oligomer having a molecular weight of several thousands and a polymer having a controlled molecular weight and a controlled molecular weight distribution can be obtained with ease by the living anionic polymerization if it is in small quantity. However, when it is adapted to the synthesis or industrial-scale production of a polymer having a molecular weight of several tens of thousand even if it is in small quantity, it is difficult to completely eliminate the effect of an active hydrogen-containing compound such as water introduced into a reaction system. Therefore, the living anionic polymerization involves the above problem to be solved for the precise control of the molecular weight of a polymer though it can control molecular weight distribution.
Recently, development of a homopolymer of a copolymer, having a phenolic hydroxyl group and a controlled structure, of alkenylphenol are desired for a resist material which achieves submicron resolution, and used for super-LSI manufacturing, as well as for a separation membrane and for a biocompatible polymeric material.
The above-mentioned polymers obtained by thermal or radical polymerization of p-vinylphenol have the following disadvantages: broad molecular weight distributions, uncontrolled structures, unremovable impurity, and easy discoloration.
Anionic polymerization of p-vinylphenol, the hydroxyl group of which is protected by tert-butyl dimethyl silyl group in advance, also has a practical disadvantage; i.e., tert-butyl dimethyl silyl chloride, which is used for the silylation, is extremely expensive.
On the other hand, the method proposed earlier by the present inventors has advantages: easy achievements of a controlled molecular weight, a controlled molecular weight distribution, and a controlled copolymer structure of alkenylphenol. In an industrial production, however, it has been found difficult to eliminate the effect of active hydrogen in such a compound as water; i.e., a precise control of molecular weight remains further to be accomplished, though the molecular weight distribution could be placed under control even in a large-scale production.
SUMMARY OF THE INVENTION
The present invention has been made in view of this and it is an object of the present invention to provide an industrial process for producing a monodisperse polymer of a conjugated diene, vinyl aromatic compound or (meth) acrylic acid ester having a controlled molecular weight and a controlled molecular weight distribution, and further a monodisperse alkenylphenol polymer.
The inventors of the present invention have conducted intensive studies to attain the above object and have found that in a process for homopolymerizing or random copolymerizing an anionic polymerizable compound such as a conjugated diene, vinyl aromatic compound or (meth) acrylic acid ester by living anionic polymerization, and a process for obtaining an alkenylphenol polymer by homopolymerizing a compound having the hydroxyl group of alkenylphenol with a saturated aliphatic protecting group or random copolymerizing the compound with a compound copolymerizable with the compound by living anionic polymerization and the eliminating the saturated aliphatic protecting group, a monodisperse polymer or monodisperse alkenylphenol polymer having a precisely controlled molecular weight is obtained by adding the compound(s) divided in multiple steps. The present invention has been accomplished based on this finding.
The present invention provides a process for producing a monodisperse polymer having a number-average molecular weight of 1,000 to 100,000 and a molecular weight distribution Mw (weight-average molecular weight)/Mn (number-average molecular weight)=1.00 to 1.50 characterized in that in the homopolymerization or random copolymerization of an anionic polymerizable compound by living anionic polymerization using an organic alkali metal and/or an alkali metal as a polymerization initiator, a target molecular weight is obtained by adding the compound divided in multiple steps.
Particularly, the above process is characterized in that the anionic polymerizable compound is a conjugated diene, vinyl aromatic compound or (meth)acrylic acid ester and the monomers are divided an added in two steps.
More particularly, the present invention is directed to a process for producing narrow polydispersity alkenylphenol polymer which has a number-average molecular weight from 1,000 to 100,000 and a molecular weight distribution Mw (weight-average molecular weight)/Mn (number-average molecular weight)=1.00 through 1.50, comprising subjecting a compound, of which OH group of the phenol residue is protected with a saturated aliphatic protecting group, to homopolymerization or random copolymerization with a copolymerizable monomer; and
thereafter, eliminating the saturated aliphatic protecting group to get an alkenylphenol polymer:
the compound mentioned above being represented by the following formula I
where R
1
is hydrogen or methyl group, and R
2
, R
3
and R
4
are respectively and independently hydrogen or an alkyl group containing 1 through 6 carbon atoms:
the homopolymerization or copolymerization mentioned above being a living anion polymerization using an organic alkali metal compound and/or an alkali metal as the initiator;
the process mentioned above being characterized in that a polymerization for adjusting the molecular weight is carried out by a first step preliminary polymerization the monomers in amounts corresponding to 50/100 through 95/100 of the target molecular weight and second step wherein the monomers are added in amounts required for obtaining the target molecular weight.
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patent: 4764572 (1988-08-01), Bean, Jr.
patent: 4791176 (1988-12-01), Birkle et al.
patent: 5081191 (1992-01-01), Quirk
patent: 5-148324 (1993-06-01), None
patent: 6-298869 (1994-10-01), None
Kobayashi Eiichiro
Muramoto Hiroo
Nobuhara Yukikazu
Jacobson Price Holman & Stern PLLC
Nippon Soda Co. Ltd.
Teskin Fred
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