Air blower apparatus

Disclosed is an air blower apparatus for conditioning a room, including synthetic resin components which come in contact with air flow. The synthetic resin components are molded from polypropylene resin, to which at least one antimicrobial agent selected from diphenylethers, N-haloalkylthio compounds, benzimidazoles, organic arsine compounds and metal alumino-silicate hydrate is mixed prior to molding of the components.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an air blower apparatus for conditioning a room 
such as an air conditioner for cooling, heating and humidifying a room, an 
air circulator for circulating the air in a room or the like. 
2. Description of the Prior Art 
When a closed room is cooled or warmed with an air conditioner or is warmed 
and humidified at the same time with an air conditioner and an air 
circulator, fungi which grow on the air filter, discharge and suction 
grilles, fan or fan casing are blown into the room and can cause people in 
the room to be affected by diseases of the respiratory system such as 
asthma. 
To solve this problem, it has been attempted to spray conventional 
antimicrobial agents on the air discharge port of the air conditioner as 
described in the Japanese Unexamined Utility Model Publication No. 
7729/1986. 
However, the application of an antimicrobial agent serves to prevent fungi 
growth but causes another problem that the antimicrobial agent may be 
easily removed by dewdrops which appear on the air discharge port of the 
air conditioner and therefore the antimicrobial effect cannot be 
maintained. 
It is an object of the invention to provide an air blower apparatus which 
is free from such problem. 
SUMMARY OF THE INVENTION 
This invention provides an air blower apparatus having synthetic resin 
components for contact with the air flow. At least one antimicrobial agent 
selected from diphenylethers, N-haloalkylthio compounds, benzimidazoles, 
organic arsine compounds and metal alumino-silicate hydrate is added to 
the synthetic resin components.

PREFERRED EMBODIMENT OF THE INVENTION 
The wording "synthetic resin components for contact with the air flow" in 
this invention means the front panel, discharge and suction grill, body 
casing, fan casing, crossflow fan, air filter or other parts of the blower 
which are made of synthetic resins and contact the air flow. The preferred 
subject is the air filter net. The synthetic resins useful as the material 
of these components are not particularly limited. Specific examples 
include polypropylene resin (hereinafter described as PP resin), 
acrylonitrile-butadienestyrene resin (ABS resin), acrylonitrile-styrene 
resin (AS resin), polystyrene resin (PS resin) and the like. 
The antimicrobial agents used for this invention are desirably those which 
are not easily decomposed at the molding temperature of the synthetic 
resin (approx. 200.degree.-250.degree. C.) and which possess antimicrobial 
effects against a variety of bacteria and fungi. We have found that the 
following five kinds of agents are preferable for meeting these criteria. 
Examples of the diphenylethers include 
2,4,4'-trichloro-2'-hydroxydiphenylether (C.sub.12 H.sub.7 Cl.sub.3 
O.sub.2) and hexachlorohydroxydiphenylether (C.sub.12 H.sub.3 Cl.sub.6 
O.sub.2), examples of the N-haloalkylthio compounds include 
N-(fluorodichloromethylthio)-phthalimide (C.sub.9 H.sub.4 Cl.sub.2 
FNO.sub.2 S), N,N-dimethyl-N'-phenyl-N'-fluorodichloromethylthiosulfamide 
(C.sub.6 H.sub.12 Cl.sub.2 FN.sub.2 O.sub.2 S.sub.2) and 
N-trichloromethylthiotetrahydrophthalimide (C.sub.6 H.sub.8 Cl.sub.3 
NO.sub.2 S). The benzimidazoles may be 2-(4-thiazolyl)benzimidazole 
(C.sub.10 H.sub.7 N.sub.3 S) and 2-(methoxycarbonylamino)benzimidazole 
(C.sub.9 H.sub.9 N.sub.3 O.sub.2); the organic arsenic compounds may be 
10,10'-oxybisphenoxyarsine (C.sub.24 H.sub.16 As.sub.2 O.sub.3) and 
arsthinol (C.sub.11 H.sub.14 AsNO.sub.3 S.sub.2); and the metal 
alumino-silicate hydrate is a salt represented by the formula Me.sup.2 /n 
O.Al.sub.2 O.sub.3.xSiO.sub.2.yH.sub.2 O (wherein Me.sup.2 represents 
Cu++, Ag++ or Zn++; n, x and y represent natural numbers). These 
antimicrobial agents are available because all of them are well known. The 
antimicrobial agents may be used singly or in admixture thereof. We have 
found that the combination use of 2,4,4'-trichloro-2'-hydroxydiphenylether 
and N-(fluorodichloromethylthio)phthalimide is preferable. 
The antimicrobial agent is used in an antimicrobially effective amount, 
generally in a concentration from 0.05 wt% to 4.0 wt% to the synthetic 
resin as the material of the component. 
It is preferable to use the antimicrobial agent in the form of inclusion 
compound because this serves to prolong the antimicrobial effect. 
Materials which are used to prepare the inclusion compound of 
antimicrobial agent can be selected from those well known in the art. 
However, is is preferable that the above mentioned metal alumino-silicate 
hydrate as the antimicrobial agent be used as the material for preparing 
the inclusion compound of the four kinds of the antimicrobial agents 
mentioned, except this alumino-silicate. In such case, the metal 
alumino-silicate hydrate is used in an amount sufficient to enclose the 
antimicrobial agent, thereby forming a suitable inclusion compound. 
The antimicrobial agent is normally mixed with the synthetic resin before 
molding the blower components. For example, pellets are firstly prepared 
from predetermined amounts of the antimicrobial agent and the synthetic 
resin, and then the resulting pellets together with synthetic resin 
pellets are heated up to a temperature of approx. 200.degree.-250.degree. 
C. to melt for forming by extruding. Methods for molding may be suitably 
selected according to the shape or kind of desired component. 
The component can be composed of a separate inner resin layer and an outer 
resin layer, wherein (1) the antimicrobial agent is added only to the 
inner resin layer or (2) it is added at a lower concentration to the outer 
resin layer than to the inner resin layer. For example, 1.0-4.0 wt% could 
be included in the inner layer and 0.05-0.9 wt% in the outer layer. In 
case (1), the outer resin layer experiences no void due to the release of 
the antimicrobial agent and hence the antimicrobial agent contained in the 
inner resin layer does not disappear by release after a short period, but 
rather, exerts a prolonged effect during a semipermanent period. In case 
(2), even if all of the antimicrobial agent in the outer resin layer is 
released, the agent contained in the inner resin layer remains owing to 
its higher concentration and can maintain its effect. 
The component having the double structure of the outer and inner resin 
layers may be formed for example by a double extruding method. 
In addition, we have found that the addition of a coupling agent to the 
resin used for manufacturing the component is preferable. Examples of the 
coupling agents include silane coupling agents such as 
vinyltrichlorosilane (CH.sub.2 .dbd.CH.dbd.Si--Cl.sub.3), 
vinyltriethoxysilane [CH.sub.2 .dbd.CH--Si--(OC.sub.2 H.sub.5).sub.3 ], 
.gamma.-glycidoxypropyltrimethoxysilane 
##STR1## 
vinyl-tris-.beta.-methoxyethoxysilane [CH.sub.2 .dbd.CH--Si--(OC.sub.2 
H.sub.4 OCH.sub.3).sub.3 ], 
N-.beta.-(aminoethyl)-.gamma.-aminopropyltrimethoxysilane[NH.sub.2 
--(CH.sub.2).sub.2 --NH--(CH.sub.2).sub.3 --Si--(OCH.sub.3).sub.3 ], and 
N-.beta.-(aminoethyl)-.gamma.-aminopropylmethyldimethoxysilane[NH.sub.2 
--(CH.sub.2).sub.2 --NH--(CH.sub.2).sub.3 -Si--(OCH.sub.3).sub.3 ]. Other 
coupling agents having a CHO radical such as glutaraldehyde 
[CHO(CH.sub.2).sub.3 CHO] are also usable. 
The coupling agent to be used is selected according to the kind of resin. 
For example, 
N-.beta.-(aminoethyl)-.gamma.-aminopropylmethyldimethoxysilane is used for 
PP resin or ABS resin. The quantity of the coupling agent is 10-50 wt% of 
that of the antimicrobial agent. 
The treatment of the coupling agent with the resin may be conducted by 
mixing the agennt and resin and extruding to make pellets. The resulting 
pellets can be mixed with the antimicrobial agent added-pellets to form 
the desired component as described above. This is an example of processing 
the coupling agent. 
The use of the coupling agent can serve to strengthen the binding of the 
antimicrobial agent and the resin and prevent the antimicrobial agent from 
disappearing due to release over a short time. 
In addition, it is preferable that the net of the air filter in the air 
blower apparatus according to this invention is made of PP resin woven or 
unwoven fabric. When the PP resin woven fabric is used for the net, it 
facilitates oil absorption due to the lipophilic nature as well as gaps 
between the threads interwoven each other. Therefore, the use of these 
fabrics for an air filter net of an air conditioner or circulating fan 
which is utilized in a kitchen or machine manufacturing factory serves to 
provide the circulation air without cooking oil or mist of processing oil. 
If the antimicrobial agent is coated on the air filter net of PP resin 
woven or unwoven fabric according to the methods of the prior art, it 
causes the drawbacks that the oil absorption is decreased, the adhesion of 
the antimicrobial agent to the PP resin fabric is weakened due to its 
being a crystalline resin and the antimicrobial agent is washed out during 
cleaning of the air filter net. However, this invention does not show such 
drawbacks, because the antimicrobial agent is included within the PP 
resin. 
EXAMPLE 
A specific example of the invention is explained as follows. In FIG. 1, 1 
is a front panel installed in the front part of an air conditioner body 2 
and equipped with a suction grille 3 and a discharge grille 5 with a 
louver 4. 
In FIG. 2 which is a cross-sectional view taken along the line II-II' of 
FIG. 1, a casing 6 of the body 2 provides a heat exchanger 7 which acts as 
an evaporator when the air conditioner is used as a heater and also as a 
condenser when used as a cooler, a cross flow fan 9 to blow air drawn from 
the room through the suction grille 3, an air filter 8 and the heat 
exchanger 7 through the discharge grille 3, a fan casing 10 to guide the 
air from the suction grille 3 to the discharge grille 5, and a drain pan 
11 to receive drained water which drops from the heat exchanger 7 when 
used as a cooler. 
The casing 6, the front panel 1, the cross flow fan 9, the fan casing 10, 
and the louver 4 are molded a synthetic resin such as ABS resin, PP resin, 
PS resin or AS resin, to which 0.6-2.0 wt% of the antimicrobial agents of 
2,4,4'-trichloro-2'-hydroxydiphenylether and 
N-(fluorodichloromethylthio)-phthalimide are added. Element 12 of the air 
filter 8 is made of woven fabric of PP resin to which is added 0.6-2.0 wt% 
of the same antimicrobial agent, and the drain pan 11 is made of a styrene 
foam to which is added with 0.6-2.0 wt% of the same agent. 
Since the component to be in contact with the room air flow is made of the 
synthetic resin including the added antimicrobial agent, the existence of 
said agent in the surface and inner parts can prevent the occurrence or 
growth of fungi and bacteria at the discharge grille 5 and the lower fan 4 
on which condensation appears in cooling; the drain pan 11 to receive 
drained water or the casing 6 the friont panel 1, the suction grille 3, 
the cross flow fan 9, the fan casing 10 and the net 12 of the air filter 9 
which are moistened in heating and humidifying. 
Next, the method for adding the antimicrobial agent into the air filter net 
and the antimicrobial effect of the net are explained as follows. 
(Manufacture of the Net) 
The antimicrobial agent [the combination of 
2,4,4'-trichloro-2'-hydroxydiphenylether and 
N-(fluorodichloromethylthio)-phthalimide] was mixed with the PP resin so 
as to be in the ratio of 6-20 wt% and extruded to make pellets. The 
resulting pellets were mixed with PP resin pellets to obtain the specified 
mixing ratio of the antimicrobial agent (0.6-2.0 wt%), and subjected into 
an extruder (molding temperature: 200.degree.-250.degree. C.) to make 
threads, followed by knitting the threads to form a net. The net and a 
resin frame were integrally molded through an injection molder, to obtain 
the filter net. 
A filter net without the addition of the antimicrobial agent was also 
manufactured for comparison. 
(Antimicrobial Effect of the Net) 
(1) An air conditioner for domestic use is usually equipped with two filter 
nets, one is installed at the left side of the blowing port and the other 
the right side thereof. In this test, the air conditioner was operated for 
a month under normal operating conditions, wherein one filter contained 
the antimicrobial agent and the other filter did not. 
After the operation, the average number of microorganisms found per unit 
square (8.times.13 cm.) of the net without the antimicrobial agent was 
2.8.times.10.sup.2, while that of the antimicrobial agent added net was 
1.4.times.10.sup.2. This result means a significant decrease of the number 
of micororganisms, because when the number found on microorganisms of the 
net without the antimicrobial agent is expressed as 100%, the decrease of 
the antimicrobial agent added-net is 50%. 
(2) The above mentioned net with the antimicrobial agent was subjected to a 
Halo test. 
In this test, fungi were cultivated in potato-dextrose agar medium at 
25.degree. C. for a week and bacteria were cultivated in agar medium added 
with yeast extract and glucose at 30.degree. C. for three days. In 
cultivation, the antimicrobial agent added filter nets (27 mm. diam.) were 
put on the medium and the width of growth inhibition zone (Halo) was 
measured. 
The results were as follows. 
______________________________________ 
Test Strain Result 
______________________________________ 
Penicillium chrysogenum 
+++ 
+++ 
Fusarium oxysporum .+-. 
.+-. 
Pestalotia sp. ++ 
++ 
Trichoderma viride - 
- 
Arthrinium sp. ++ 
+++ 
Staphylococcus aureus 
+++ 
+++ 
Bacillus subtilis +++ 
+++ 
Saccharomyces cerevisiae 
++ 
++ 
Escherichia coli. +++ 
+++ 
______________________________________ 
Note: +++represents 10 mm or more growth inhibition zone 
++represents 5-10 mm growth inhibition zone 
+represents 3-5 mm 
.+-.represents 3 mm or less 
-represents no growth inhibition zone but mycellium do not grow on the 
filter 
(Test with Practical Equipment) 
The effect of the antimicrobial agent added-filter net as prepared by the 
above mentioned procedure was evaluated by measuring the number of 
microorganisms (bacteria, molds and osmophilic fungi) blown from the 
blowing port of the air conditioner installed with filter net. 
Two air conditioners, one with the antimicrobial agent added-filter net and 
the other with the filter net without the antimicrobial agent, were 
normally operated simultaneously in one room. 
After operating for the specified period, three culture media were placed 
on the part of the blowing port of each the air conditioner so as to be 
exposed to the blown air. After sampling by 10 minutes' operation, the 
culture media were removed and bacteria were cultivated at 30.degree. C. 
for three days, molds and osmophilic fungi at 25.degree. C. for seven 
days. These procedures were performed every day from three days to twenty 
days after the begining of the operation. 
The average numbers of bacteria, molds and osmophilic fungi were as 
follows. 
______________________________________ 
Bacteria 
Molds Osmophilic Fungi 
______________________________________ 
Filter without 
379 28 18 
Antimicrobial agent 
(100%) (100%) (100%) 
Antimicrobial agent 
42 16 18 
added Filter 
(11.1%) (57.1%) (61.1%) 
______________________________________ 
As shown in the above table, the antimicrobial agent added-filter according 
to this invention rapidly reduces the number of microorganisms blown from 
the blowing port. 
It was also proved that the antimicrobial effect is maintained for at least 
12 months.