Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-01-29
2001-07-31
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S101000, C525S105000, C525S106000, C525S474000, C524S588000, C524S806000, C524S837000, C524S860000, C524S863000, C524S866000, C528S032000, C528S033000
Reexamination Certificate
active
06268440
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a novel and useful process for producing a water-base resin, to a water-base curable resin composition comprising the water-base resin obtained by the production process as an essential component, to a water-base coating material comprising the water-base curable composition as an essential component, and to a process for forming a coating film using the water-base coating material.
More specifically, the present invention relates to a process for producing a water-base resin, the process being characterized by the following steps: mixing a specific polysiloxane and a composite resin comprising both a specific polymer segment having at least one type of hydrophilic group selected from the group consisting of an anionic group, a cationic group, and a non-ionic group and a specific polysiloxane segment having silicon atoms; bringing about a condensation reaction at least partially between the composite resin and the polysiloxane, if necessary; and thereafter dispersing or dissolving the resulting mixture or at least partially condensed product into a water-base medium. The present invention also relates to a water-base curable resin composition which comprises as an essential component a water-base resin obtained by the above process.
Even more specifically, the present invention relates to a process for producing a water-base resin having a high polysiloxane content, which possesses excellent curability at room temperature and excellent storage stability, and which may be formed into a cured material; the cured material obtained is excellent in various properties such as durability represented by gloss retention and acid rain resistance, solvent resistance, resistance to chemicals, and water resistance, and is extremely excellent in stain resistance during outdoor exposure.
In addition, the present invention relates to a water-base curable resin composition which comprises the water-base resin obtained by the above production process as an essential component and which, in particular, possesses excellent curability. Furthermore, the present invention relates to a novel and highly useful process for forming a coating film, according to which a coating film can be formed which is excellent in various properties such as durability as mentioned above, and is extremely excellent in stain resistance during outdoor exposure.
Such a water-base curable resin composition according to the present invention can be effectively used for various applications such as in agents for treating fibers, adhesives, sealants, and coating materials for exteriors of architecture, building materials, vehicles, and heavy duty uses.
In addition, a process for forming a coating film according to the present invention is useful as a process for forming a top-coating film on various articles to such as various structural materials, building materials, automobiles, and the like.
BACKGROUND ART
As water-base curable resin compositions for coating materials, a water-base curable resin composition has been hitherto widely used which comprises a water-base resin and one of various curing agents such as an epoxy resin, an isocyanate resin, and an amino resin. The water-base resin mentioned above can be obtained by neutralizing a vinyl polymer, having a basic or acid group together with a functional group such as a hydroxyl group, with an acidic or basic compound, and thereafter dispersing or dissolving the resulting neutralized vinyl polymer in a water-base medium (Japanese Patent Application, First Publication (Kokai) No. Hei 4-359075, Japanese Patent Application, First Publication (Kokai) No. Hei 6-1948, Published Japanese Translation of PCT International Publication (Kohyo) for Patent Application, Publication No. Hei 8-510000, and European Patent Application, Publication No. EP661320-A1).
However, cured coating films obtained from such water-base curable resin compositions which have hitherto been used in which a water-base resin serves as a base resin component are insufficient in durability during outdoor exposure such as gloss retention and acid rain resistance, or in stain resistance during outdoor exposure. Accordingly, there have been problems in that conventional water-base resins can almost never be put into uses where high durability or stain resistance during outdoor exposure is demanded.
On the other hand, in order to improve gloss retention during outdoor exposure of the coating film which is obtained from the water-base vinyl polymer as described above, modifications of the polymer by polysiloxanes have been investigated. However, at present, a modified resin having a high polysiloxane content which is excellent in both storage stability and curability at room temperature has not yet been obtained.
Thus, the present inventors commenced study in order to solve all of these various problems which existed in the prior art as described above.
Accordingly, the object to be achieved by the present invention is to provide a novel and useful process for producing a water-base resin which possesses both excellent storage stability and excellent curability at room temperature, and which can produce a cured material having excellent durability such as gloss retention and acid rain resistance during outdoor exposure, and exhibiting extremely excellent stain resistance during outdoor exposure. Another object to be achieved by the present invention is to provide a novel and useful water-base curable resin composition which comprises the novel and useful water-base resin obtained by the above production process. The water-base curable resin composition is excellent in curability at room temperature and is capable of producing a cured coating film which possesses extremely excellent durability.
Yet another object to be achieved by the present invention is to provide a process for forming a coating film in which a coating material comprising the above water-base curable resin composition is used.
DISCLOSURE OF INVENTION
As a result of research to achieve the above object, the present inventors have found a water-base resin having both excellent storage stability and excellent curability at room temperature. The water-base resin is obtained by the following steps: mixing a specific polysiloxane which has a specific essential structural unit and a specific composite resin comprising a specific polysiloxane segment, having a silicon atom bearing a hydrolyzable group or a hydroxyl group together with an organic group, and a specific polymer segment having at least one type of hydrophilic group selected from the group consisting of an anionic group, a cationic group, and a non-ionic group; bringing about a condensation reaction at least partially between the polysiloxane and the composite resin, if necessary; and thereafter dispersing or dissolving the mixture into a water-base medium. Thus, the present inventors have established a process for producing the water-base resin. In addition, the present inventors have found that a water-base curable resin composition which comprises the water-base resin as an essential component can produce a cured material having excellent property in durability such as acid rain resistance and gloss retention during outdoor exposure (hereinafter referred to as “weathering resistance”), and excellent stain resistance during outdoor exposure. Accordingly, the present inventors have become confident that the above object to be achieved by the present invention could be successfully achieved, and thus the present invention was completed.
That is to say, the present invention basically provides a process for producing a water-base resin, the process comprising the following steps: mixing a composite resin (C) and a polysiloxane (D), bringing about a condensation reaction partially between them if necessary, and thereafter dispersing or dissolving the resulting mixture or partially condensed product into a water-base medium. The composite resin (C) mentioned above comprises a polymer segment (B) and a polysiloxane segment (A) which has at least o
Kinoshita Hiroshi
Kudo Shin-ichi
Ooka Masataka
Armstrong Westerman Hattori McLeland & Naughton LLP
Dainippon Ink and Chemicals Inc.
Dawson Robert
Robertson Jeffrey B.
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