Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-06-13
2002-07-02
Pezzuto, Helen L. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S259000, C526S313000, C526S328500, C548S255000, C548S257000
Reexamination Certificate
active
06414100
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a novel bis(benzotriazolyl phenol) compound suitable for use as an ultraviolet absorber, and also to a resin composition and a coating material respectively containing the novel compound.
BACKGROUND ART
Under the advances of high-performance polymer materials, there is an increasing need to impart improved weather resistance to polymer materials. Various types of ultraviolet absorbers have been developed for the purpose of imparting increased weather resistance to resins. However, conventionally-known ultraviolet absorbers have various problems since most of them are of low-molecular additive-type.
Specifically, conventional ultraviolet absorbers have higher vapor pressures because of their low-molecular nature and thus show a tendency to volatilize when blended in resins for fabrication, which reduces yield rates, causes contamination of molds or dies, and injures workers' health. Also, they are reported to bleed out from fabricated products or coating surfaces, or dissolve out with the prolonged exposure at working atmosphere to rain or water containing detergents, thereby damaging product appearances and also making it difficult for those products to retain their light stability over a long period.
For the purposes of solving the above-described problems, methods have been recently proposed which utilize reactive-type ultraviolet absorbers or polymeric-type ultraviolet absorbers prepared by polymerizing the reactive-type ultraviolet absorbers to impart the increased ultraviolet-absorbing capacity.
For example, Japanese Patent Publication No. Sho 38-25036 and Japanese Patent Laid Open No. Hei 5-271203 describe benzotriazole-based ultraviolet absorbers having an addition polymerized side chain and weather-resistant resins containing those absorbers as compolymeric components. Because these ultraviolet absorbers are introduced by optional proportions into resins for chemical bonding to their polymer chains, the occurrences of bleed-out, extraction by rainwater and vaporization thereof at high-temperature processings, which have been conventional problems, can be avoided to thereby impart the increased long-term weather resistance to those resins.
However, since the above-described reactive-type ultraviolet absorbers have only one addition polymerized side chain, their addition to thermosetting resins tends to adversely affect properties inherent to those thermosetting resins. Particularly when desired to introduce ultraviolet screening capability to ultraviolet or electron beam curable resins, a large amount of ultraviolet absorber must be added thereto. This results in a marked reduction of crosslinking density. Curing by the crosslinking accordingly becomes difficult to impart the sufficient levels of hardness, abrasion resistance to those resins. Therefore, they can not be used as coating materials purposed to protect molded or extruded products.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a novel compound having a utility as an ultraviolet absorber which can solve the above-described problems, a resin composition and a coating material respectively containing the novel compound.
The bis(benzotriazolyl phenol) compound of the present invention is a novel compound represented by the following general formula (1):
(wherein: A represents a methylene group, a (CH
3
)
2
C group or a C
2
H
5
(CH
3
)C group; R
1
and R
6
, either identical to or different from each other, represent a hydrogen atom, an alkyl group having 1-4 carbon atoms, an aryl group, an alkoxy group having 1-4 carbon atoms or a halogen atom; R
2
and R
4
, either identical to or different from each other, represent a straight-chain or branched alkylene group having 1-6 carbon atoms; R
3
and R
5
each represents a hydrogen atom or a methyl group; and 1, m and n each denotes 0 or 1.)
The bis(benzotriazolyl phenol) compound of the present invention, as represented by the above-specified general formula (1), has a good ultraviolet-absorbing capacity for its high molecular absorption coefficient, an extremely low vapor pressure and a high thermal stability. Accordingly, it shows little vaporization when blended in resins and can be blended in resins stably without showing the tendency to decompose. This makes the compound suitable for use as an additive-type ultraviolet absorber.
Also, the bis(benzotriazolyl phenol) compound (1) of the present invention has two highly-reactive addition-polymerizable groups in a molecule. The copolymerization thereof with an addition polymerizable monomer thus allows introduction of optional proportions of ultraviolet-absorbing units into a resulting polymer. The resulting ultraviolet-absorbing copolymer has such an extremely low vapor pressure that it hardly loses its ultraviolet-absorbing capacity even when exposed to heat during fabrication. Also, this ultraviolet-absorbing copolymer, when contained in resins, shows no tendency to bleed out from resin products, so that it is able to impart the sufficient long-term weather resistance to the resin products.
Also, the compound of the present invention has an extremely low vapor pressure and a high decomposition temperature, as described above, so that its vaporization, decomposition and the like are not likely to occur even during polymerization at high temperatures. Accordingly, copolymerization thereof with unsaturated polymers results in the highly efficient production of weather-resistant polymers with optional molecular weights.
Also, the compound of the present invention has such a structure that another ultraviolet-absorbing molecular group is located on a carbon atom adjacent to a phenolic hydroxyl-substituted carbon atom. This structure serves to hinder the phenolic hydroxyl-group, which plays the most important roll in the development of ultraviolet absorbing capacity, from reacting with metal ions, so that the compound of the present invention can exhibit an excellent ultraviolet-absorbing performance even in the presence of metal ions.
Unlike the conventional reactive-type ultraviolet absorbers, the compound of the present invention has plural addition polymerizable groups, i.e., (meth)acryloyl groups. This makes it suitable for use as an ultraviolet-absorbing crosslinking agent. Accordingly, when incorporated in active energy radiation curable resins, such as ultraviolet and electron beam curable resins, the ultraviolet absorber of the present invention itself serves as a crosslinking agent so that the reduction in crosslinking density of those resins can be avoided. This results in imparting excellent weather resistance and ultraviolet screening capability to those resins without adversely affecting their hardness, chemical resistance and abrasion resistance.
Specific examples of those groups represented in the general formula (1) are listed below.
Examples of alkyl groups having 1-4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl groups and the like.
Examples of aryl groups include phenyl, naphthyl groups and the like. A substituting group, such as an alkyl group having 1-4 carbon atoms, an alkoxy group having 1-4 carbon atoms, a halogen atom or the like, may be located on the aromatic ring.
Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy groups and the like.
Examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Illustrative of alkylene groups having 1-6 carbon atoms are straight-chain and branched groups, including methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, ethylidene, propylene, propylidene, ethylethylene, 2-butylidene, 1-methyl trimethylene, 2-methyl trimethylene, 2,2-dimethyl trimethylene.
Specific examples of bis(benzotriazolyl phenol) compounds (1) of the present invention include the following compounds:
2,2′-methylenebis[6-(2H-benzotriazole-2-yl)-4-(meth) acryloyloxy-2-hydroxybenzene],
2,2′-methylenebis[6-(2H-benzotriazole-2-
Akada Mitsuo
Daimon Emiko
Mori Koji
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