Functional groups-terminated vinyl polymers

Details Functional groups-terminated vinyl polymers Functional groups-terminated vinyl polymers

1998-07-28

2001-08-14

Moore, Margaret G. (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S328000, C526S346000

Reexamination Certificate

active

06274688

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a crosslinking silyl-, alkenyl- or hydroxy-terminated vinyl polymer. More particularly, it relates to a vinyl polymer which has a narrow molecular weight distribution, hence is easy to handle.
PRIOR ART
Intramolecular crosslinking silyl group-containing vinyl polymers, in particular (meth) acrylic polymers, are used in weather-resistant paints utilizing the high weather resistance based on their main chain and crosslinking points. These (meth)acrylic polymers are generally produced by copolymerizing a crosslinking silyl-containing (meth)acrylic monomer with one or more other monomers and therefore have crosslinking silyl groups at random positions in the molecular chain, hence they are difficult to use as rubber-like materials. On the other hand, attempts have been made to produce (meth)acrylic polymers having crosslinking silyl groups at molecular ends for use as sealants or adhesives. For producing (meth)acrylic polymers having terminal crosslinking silyl groups, Japanese Kokoku Publication Hei-03-14068, for instance, discloses a method comprising polymerizing a (meth)acrylic monomer in the presence of a crosslinking silyl-containing mercaptan, a crosslinking silyl-containing disulfide and a crosslinking silyl-containing radical polymerization initiator; Japanese Kokoku Publication Hei-04-55444 discloses a method comprising polymerizing a acrylic monomer in the presence of a crosslinking silyl-containing hydrosilane compound or a tetrahalosilane; and Japanese Kokai Publication Hei-06-211922 describes a method for producing crosslinking silyl-terminated (meth)acrylic polymers which comprises first synthesizing a hydroxy-terminated acrylic polymer by using a hydroxyl-containing polysulfide in a larger amount as compared with the initiator and then converting the hydroxyl groups.
Meanwhile, it is known that alkenyl-terminated polymers, when crosslinked by themselves or using a curing agent such as a hydrosilyl-containing compound, give cured products excellent in heat resistance and durability. The main chain skeletons of such polymers include polyether polymers such as polyethylene oxide, polypropylene oxide and polytetramethylene oxide; hydrocarbon polymers such as polybutadiene, polyisoprene, polychloroprene, polyisobutylene and hydrogenation products derived from these; polyester polymers such as polyethylene terephthalate, polybutylene terephthalate and polycaprolactone; and polysiloxane polymers such as polydimethylsiloxane, among others. They are used in various applications according to the characteristics of the respective main chain skeletons.
As compared with those polymers mentioned above which are obtained by ionic polymerization or condensation polymerization, alkenyl-terminated vinyl polymers obtainable by radical polymerization have scarcely been put to practical use. Among vinyl polymers, meth(acrylic) polymers have high weather resistance, transparency and other characteristics which the above-mentioned polyether polymers or polyester polymers cannot have. For example, vinyl polymers having alkenyl groups in side chains are used in paint compositions for obtaining high weather resistance.
If alkenyl-terminated vinyl polymers could be obtained in a simple manner, cured products superior in physical characteristics to cured products from vinyl polymers having alkenyl groups in side chains could be obtained. Therefore, a large number of researchers have made investigations in an attempt to establish a method of producing the same. It is not easy, however, to produce them on a commercial scale.
Japanese Kokai Publication Hei-01-247403 discloses a method for synthesizing vinyl polymers having alkenyl groups on both ends which uses an alkenyl-containing disulfide as a chain transfer agent, and Japanese Kokai Publication Hei-06-211922 discloses a method for synthesizing vinyl polymers having alkenyl groups on both ends which comprises synthesizing a vinyl polymer having hydroxyl groups on both ends using a hydroxyl-containing disulfide and then utilizing the reactivity of the hydroxyl groups. By these methods, however, it is difficult to introduce alkenyl groups at both ends without fail and it is impossible to obtain cured products having satisfactory characteristics. For introducing alkenyl groups at both ends with certainty, it is necessary to use the chain transfer agent in large amounts, and this offers a problem from the production process viewpoint. Since, in these methods, ordinary radical polymerization techniques are used, it is difficult to control the molecular weight and molecular weight distribution (ratio of weight average molecular weight to number average molecular weight).
It is also known that hydroxyl-terminated polymers, when crosslinked using a compound having functional groups capable of reacting with a hydroxyl group, for example an isocyanate compound, as a curing agent, give cured products excellent in heat resistance and durability, among others.
As the main chain skeletons of such hydroxyl-terminated polymers, there may be mentioned, as in the case of alkenyl-terminated polymers, polyether polymers such as polyethylene oxide, polypropylene oxide and polytetramethylene oxide; hydrocarbon polymers such as polybutadiene, polyisoprene, polychloroprene and polyisobutylene and hydrogenation products derived from these; and polyester polymers such as polyethylene terephthalate, polybutylene terephthalate and polycaprolactone, among others. Said polymers are used in various applications according to the main chain skeleton and mode of crosslinking thereof.
Vinyl polymers, in particular (meth)acrylic polymers, have such characteristics that the above-mentioned polyether polymers, hydrocarbon polymers or polyester polymers cannot have, for example high weather resistance and transparency, and those having hydroxyl groups in side chains are utilized in weather-resistant paint compositions, for instance.
If hydroxyl-terminated vinyl polymers could be obtained in a simple manner, cured products superior in physical characteristics to cured products from vinyl polymers having hydroxyl groups in side chains could be obtained. Therefore, a large number of researchers have made investigations in an attempt to establish a method of producing the same. It is not easy, however, to produce them on a commercial scale.
Japanese Kokai Publication Hei-05-262808 discloses a method for synthesizing (meth)acrylic polymers having hydroxyl groups at both ends which comprises using a hydroxyl-containing disulfide as a chain transfer agent. For introducing hydroxyl groups at both ends with certainty, it is necessary to use the chain transfer agent in large amounts as compared with the initiator, and this offers a problem from the production process viewpoint. Japanese Kokoku Publication Hei-01-19402 discloses a method for producing (meth)acrylic polymers having hydroxyl groups at both ends which comprises using hydrogen peroxide as an initiator. It is difficult, however, to introduce, by this method, hydroxyl groups at both ends with certainty. In fact, the method actually employed there comprises copolymerizing a hydroxyl-containing vinyl monomer (e.g. 2-hydroxyethyl methacrylate). Further, Japanese Kokai Publication Hei-04-132706 discloses a method for hydroxyl-terminated vinyl polymers which comprises producing a halogen-terminated (meth)acrylic polymer by polymerizing a (meth)acrylic monomer or monomers using a telogen such as methylene dibromide and reacting the terminal halogen atoms with a nucleophilic agent such as a diol compound, a hydroxyl-containing carboxylic acid, a hydroxyl-containing amine or the like for substitution. By this method, however, it is still difficult to achieve high-rate hydroxyl group introduction at both ends, since the chain transfer of the telogen is not sufficient.
In addition, since the methods mentioned above all use ordinary radical polymerization techniques, the polymers obtained have a broad molecular weight distribution (ratio of weight average molecular weight to number av

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