Stock material or miscellaneous articles – Composite – Of polyester
Reexamination Certificate
2000-07-14
2002-11-05
Chen, Vivian (Department: 1773)
Stock material or miscellaneous articles
Composite
Of polyester
C428S482000, C428S483000, C428S522000, C106S015050, C106S018260, C106S018270, C106S018300, C106S018310, C106S018360, C424S600000, C424S601000, C424S604000, C424S606000, C424S617000, C424S641000, C424S650000, C424S657000, C424S660000, C424S682000, C424S688000, C424S691000, C424S724000
Reexamination Certificate
active
06475631
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an antimicrobial agent which comprise glass containing zinc oxide in a high concentration, an antimicrobial resin composition containing the agent and antimicrobial artificial marble.
The antimicrobial agent of the present invention has a high antimicrobial effect and hardly causes any discoloration with time during processing, storing and practically using the same. Therefore, the antimicrobial agent can be incorporated into a variety of high molecular weight compounds to obtain an antimicrobial resin composition showing antifungal properties, anti-algal properties and antimicrobial properties. The antimicrobial resin composition can be processed and used as, for instance, fibrous goods, paint and varnish products and molded articles.
The antimicrobial artificial marble of the present invention is a molded article of a resin mainly comprising a (meth) acrylic resin or an unsaturated polyester resin in which the antimicrobial agent of the present invention is incorporated. Alternatively, the antimicrobial artificial marble is a molded article comprising a base resin, which comprises a (meth) acrylic resin or an unsaturated polyester resin, and a gel coat layer of the antimicrobial agent of the present invention and a (meth) acrylic resin or an unsaturated polyester resin, applied to the surface of the base resin.
2. Details of Prior Art
There have conventionally been known such inorganic antimicrobial agents as those comprising antimicrobial metals such as silver, copper or zinc supported on, for instance, apatite, zeolite, glass, zirconium phosphate or silica gel. These inorganic antimicrobial agents have high safety and do not undergo any volatilization and decomposition as compared with organic antimicrobial agents. Therefore, the inorganic antimicrobial agents show a long-lasting or sustained antimicrobial effect and excellent heat resistance. For this reason, these antimicrobial agents are incorporated into a variety of high molecular weight compounds to form antimicrobial resin compositions, the resulting resin compositions are formed into antimicrobial processed articles such as fibrous and film-like articles or various molded articles, which have been used in various fields.
Among these inorganic antimicrobial agents, those comprising glass containing antimicrobial metals such as silver, copper or zinc have such characteristic properties that the particle sizes and refractive indexes of the agents and the ability thereof to release antimicrobial metals can, for instance, be easily controlled depending on the intended purposes. Accordingly, they are incorporated into a variety of resin compositions while making the most use of the foregoing characteristic properties.
In general, an antimicrobial agent consisting of antimicrobial metal-containing glass and a resin-molded article containing the agent have a tendency of getting colored when they are heated or exposed to ultraviolet rays. This tendency is conspicuous if the antimicrobial agents comprise glass containing silver or copper.
Among the antimicrobial metals, zinc is a metal whose coloration is relatively difficult. Accordingly, there have been proposed antimicrobial agents comprising glass containing zinc in a high concentration (Japanese Un-Examined Patent Publication (hereunder referred to as “J. P. KOKAI”) Nos. Hei-7-257938, Hei 8-175843, Hei 11-29343, Hei 11-60268, Hei 11-100227 and Hei 11-100228).
There is disclosed, in J. P. KOKAI No. Hei 7-257938, an antimicrobial agent comprising soluble glass, which contains 15 to 50 mole % of ZnO, 40 to 80 mole % of B
2
O
3
and 5 to 30 mole % of Na
2
O.
J. P. KOKAI No. Hei 8-175843 discloses an antimicrobial agent consisting of glass, which comprises 40 to 55 mole % of P
2
0
5
, 35 to 45 mole % of ZnO, 5 to 15 mole % of Al
2
O
3
and 1 to 10 mole % of B
2
O
3
and an antimicrobial agent comprising the foregoing glass and Ag
2
O in an amount of 0.01 to 1.0% by weight per 100 parts by weight of the glass. The antimicrobial agent consisting of the foregoing glass is insufficient in the antimicrobial power and therefore, it is preferred to incorporate Ag
2
O into the glass antimicrobial agent. However, the Ag
2
O-containing antimicrobial agent has a tendency of getting colored pale brown when irradiated with ultraviolet rays.
J. P. KOKAI No. Hei 11-29343 proposes antimicrobial glass powder of ZnO—B
2
O
3
—SiO
2
type one (25 to 80 mole % ZnO, 5 to 50 mole % B
2
O
3
, 1 to 70 mole % SiO
2
; the total content of these three components ranges from 72.5 to 100 mole %, in Examples 1 to 9) whose Na
2
O content is not more than 4 mole %. In this patent, it is intended to improve the appearance of resin articles admixed with the glass powder or to eliminate any rough feeling and any reduction of the gloss due to changes with time by limiting the Na
2
O content to not more than 4 mole %. In respect of the composition of the antimicrobial agent, however, it comprises only a small amount of alkali metal ions, which serve as a component for modifying the network of glass. Therefore, the solubility of glass is low and there is sufficient room for improvement in antimicrobial property.
J. P. KOKAI No. Hei 11-60268 discloses antimicrobial glass having the following composition, as expressed in terms of “% by weight”: 55 to 65% ZnO, 18 to 30% B
2
O
3
, 8 to 20% SiO
2
, 0 to 10% MgO and 0 to 6% Na
2
O.
J. P. KOKAI No. Hei 11-100227 discloses an antimicrobial agent consisting of ZnO—P
2
O
5
type glass having the following composition as expressed in terms of “mole %”: 46 to 80% ZnO, 5 to 50% P
2
O
5
, 0 to 30% B
2
O
3
+SiO
2
, 0 to 40% RO (wherein RO is at least one member selected from the group consisting of MgO, CaO, SrO and BaO), 0 to 20% R
2
O (wherein R
2
O is at least one member selected from the group consisting of Li
2
O, Na
2
O and K
2
O).
J. P. KOKAI No. Hei 11-100228 discloses an antimicrobial agent consisting of ZnO—P
2
O
5
type glass having the following composition as expressed in terms of “mole %”: 25 to 70% ZnO, 5 to 40% P
2
O
5
, 0 to 35% B
2
O
3
, 0 to 20% SiO
2
, 0 to 30% MgO, 0 to 30% CaO, 0 to 20% SrO, 0 to 15% BaO, 0 to 25% Li
2
O, 0 to 25% Na
2
O, 0 to 25% K
2
O, 0 to 20% TiO
2
, 0 to 10% ZrO
2
, 0 to 20% La
2
O
3
and 0 to 15% Al
2
O
3
.
The foregoing antimicrobial agents consisting of glass containing zinc oxide in a high concentration have a tendency of reducing their antimicrobial power observed after immersion thereof in warmed water and therefore, there is still room for improvement in water resistance.
The artificial marble has widely been used as a construction material excellent in heat resistance, water resistance, wear resistance and aesthetic appearance in, for instance, kitchen counters, washing stands, and goods for toilets and bathrooms. Most of these products are used in water-circulated environment, which is susceptible for the growth of bacteria and molds. For this reason, there has been a great need for the impartment of a function for preventing any adhesion of bacteria and molds and a function for inhibiting any growth thereof to the artificial marble. In particular in, for instance, hospitals, schools and public facilities, which are used by many and unspecified persons, there has also intensively been desired for the impartment of antimicrobial effect to the artificial marble, while taking into consideration a risk of the nosocomial infection with methicillin resistant Staphylococcus aureus (MRSA) and mass food poisoning due to coliform bacillus O-157.
To respond to these social requirements, there have been tried, for instance, the incorporation of an antimicrobial agent into the artificial marble or the application thereof onto the surface of the marble. In general, the antimicrobial agents can roughly be divided into organic and inorganic ones, but it would be doubtful whether the former has sufficient long-lasting antimicrobial effect and safety. On the other hand, the latter is excellent in these properties. However, most of the inorganic antimic
Sugiura Koji
Yamamoto Noriyuki
Yamato Satoshi
Chen Vivian
Toagosei Co. Ltd.
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