Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-10-14
2002-08-13
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...
C526S317100, C526S318400, C526S319000, C526S329000, C526S347000
Reexamination Certificate
active
06433118
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a novel copolymer of 4-(1-methylethenyl)phenol, a (meth)acrylate and a (meth)acrylic acid (PIPE copolymer) as well as a manufacturing process therefor and a solution containing thereof. In particular, it provides a copolymer of 4-(1-methylethenyl)phenol, a (meth)acrylate and a (meth)acrylic acid useful as, for example, a base polymer in a positive photosensitive composition used for, e.g., manufacturing a color filter; relates to a process for manufacturing the copolymer from industrially available 4-(1-methylethenyl)phenol, a (meth)acrylate and a (meth)acrylic acid; and provides a solution comprising the copolymer containing particular concentrations of remaining monomer components.
Furthermore, the copolymer of this invention is useful as a metal finishing agent for protecting a metal surface and improving corrosion resistance and paint-adhesion property of the metal surface.
2. Description of the Related Art
Recently, a color filter has been extensively used for a variety of multicolored liquid-crystal color displays such as a liquid-crystal color television. Such a color filter has been conventionally manufactured by, for example, screen printing and electrodeposition. However, as a color display has been improved for its resolution, it has been more important to refine a pattern. Thus, a variety of patterning processes utilizing photolithography have been investigated.
For example, JP-A 8-94827 discloses a process for manufacturing a color filter comprising the steps of (1) forming a transparent conductive layer on a transparent substrate; (2) forming a positive photosensitive coating layer; (3) exposing a part of the transparent conductive layer; (4) forming a colored area by electrodeposition; and (5) repeating steps (3) and (4) as required. Of these steps, a pattern refinement level depends on steps (2) and (3), in which photolithography is used. In particular, it significantly depends on a positive photosensitive composition applied on the transparent conductive layer. The above invention employs a positive photosensitive composition essentially comprising (a) a polymer containing both carboxyl and hydroxyphenyl groups in one molecule, (b) a compound containing two or more vinyl ether groups in one molecule, and (c) a compound generating an acid by irradiating an active energy beam.
This photosensitive composition is developed as follows; by heating the film on which the positive photosensitive composition has been applied, an addition reaction of the carboxyl group and/or hydroxyphenyl group with the vinyl ether group forms a crosslink, which is insoluble to a solvent or an alkali developing solution, and then, after irradiating with an active energy beam and then, as necessary, heating the film, an acid generated in the irradiated area acts as a catalyst to break the crosslink structure and thus to again make the irradiated area soluble to a solvent or an alkali developing solution. For further improving a resolution, a preferable polymer (base polymer) in a positive photosensitive composition is one containing both carboxyl and hydroxyphenyl groups in one molecule which meets all the following five requirements as much as possible;
(a) a higher solubility to a solution which solves a crosslinking agent, an acid-generating agent and others (solvent solubility);
(b) a certain dissolution rate of the broken crosslink moieties in an alkali developing solution after exposure (dissolution rate in an alkali developing solution);
(c) good diffusivity of an acid generated by irradiation with an active energy beam (acid diffusivity);
(d) transparency of a photosensitive coating at an exposure wavelength (transparency); and
(e) thermal stability during the heating step after application of the film and exposure (thermal stability).
As an example of a polymer meeting these requirements to some degree, a copolymer from p-hydroxystyrene, n-butyl. acrylate and acrylic acid has been disclosed in, for example, JP-A 8-94827 and 8-94829. We have, however, investigated the copolymer for its performance and have come to a conclusion that it is insufficiently soluble in a solvent or thermally stable.
A main starting material, p-hydroxystyrene, for the copolymer may be prepared by any of conventional processes; for example, (a) reacting p-tert-butoxyphenyl halide with metal magnesium to form p-tert-butoxyphenylmagnesium halide, which is then reacted with vinyl halide in the presence of a nickel-phosphine complex catalyst to form p-tert-butoxystyrene (JP-A 1-106835), and then breaking the tert-butoxy group with, for example, an acid to provide p-hydroxystyrene; and (b) converting p-halogenophenol via Grignard reaction into p-(t-butoxy)phenylmagnesium halide, which is then reacted with tri-n-alkyl borate, hydrolyzing a resulting reaction product, and treating a product with hydrogen peroxide to provide p-hydroxystyrene (JP-A 62-39536).
For both processes, there are many problems; for example, the process consists of complex multiple stages, metal components such as magnesium and nickel must be removed from a product, and using magnesium halide leads to a large amount of metal halide, a byproduct, which requires complicated treatment. In the process described in (a), an expensive complex containing phosphine ligand is used as a catalyst, and therefore, recovery and recycle of the catalyst is indispensable, which makes the process more complicated. In the process described in (b), a large amount of tri-n-alkyl borate must be used, which makes separation of the product from the borate and treatment of the borate more complicated. Thus, p-hydroxystyrene cannot be said to be an industrially available starting material. A copolymer from the compound has not, therefore, been used as a base polymer for a positive photosensitive composition.
On the other hand, 4-(1-methylethenyl)phenol can be readily prepared by thermal decomposition of 2,2-bis(4′-oxyphenyl)propane (hereinafter, referred to as “bisphenol A” (a popular name)) (e.g., JP-B 56-52886). Therefore, industrially available 4-(1-methylethenyl)-phenol has been paid attention. Furthermore, it is expected that the compound has considerably different properties such as higher thermal stability or acid-diffusivity and modified solubility because of effects of its &agr;-methyl-group. A copolymer prepared using 4-(1-methylethenyl)phenol as a monomer has been intensely investigated for a variety of applications.
For example, JP-As 6-289608 and 9-292709 disclose binary copolymers of 4-(1-methylethenyl)phenol and tert-alkyl acrylate as an example of a polymer for a radiosensitive (resist) composition. On irradiating an active energy beam, these copolymers change solubility in their irradiated part due to an acid derived from a compound capable of generating an acid by an active beam, and then may act as a positive resist by using an alkali developing solution. Thus, the technique utilizes instability of a tert-alkyl ester group to an acid. Such a copolymer, however, has an insufficient dissolution rate in an alkali developing solution and insufficient acid diffusivity, and is poorly reactive to a vinyl ether compound as a crosslinking agent. It cannot be, therefore, used as it is.
JP-A 61-293249 discloses a binary copolymer of 4-(1-methylethenyl)phenol and n-butyl acrylate as an example of a copolymer for a resin composition exhibiting damping property. The copolymer has an extremely lower dissolution rate in an alkali developing solution and is poorly compatible with a vinyl ether compound. It cannot be, therefore, used as it is.
On the other hand, a variety of techniques have been developed, in which a metal surface is chemically treated to form a non-metallic film over the metal for improving surfacequality. For example, JP-As 59-207971, 59-207972, 1-172406 and 1-177380 disclose that derivatives of poly-4-vinylphenol are useful as such a metal finishing agent. These metal finishing agents, however, exhibit corrosion. resistance or paint adhesion property insuffic
Fukuda Ritsuko
Ikeda Keiichi
Takao Toshiro
Yamamoto Yoshihiro
Burns Doane Swecker & Mathis L.L.P.
Mitsui Chemicals Inc.
Pezzuto Helen L.
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