Far infrared ray emitting, odor-absorbing material

A far infrared ray emitting, odor-absorbing material is disclosed. The material comprises cellulose acetate fiber having adhered thereto an ultrafine powder of alumina hydrate or silica hydrate which is chemically produced in an aqueous dispersion of the cellulose acetate fiber. The material possesses a high far infrared ray emitting, odor-absorbing capability as well as many characteristics inherently possessed by cellulose acetate fibers, and can expand the utility of cellulose acetate in such fields as sanitary, health-care, and medical fields.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a far infrared ray emitting, odor-absorbing 
material which is made of cellulose fiber, especially of cellulose acetate 
fiber, and an inorganic core material having adhered thereto an ultrafine 
powder of alumina hydrate or silica hydrate which is chemically produced 
in an aqueous dispersion of said inorganic core material. 
2. Description of the Background 
Fiber products including textiles, lace, knits, nonwoven fabrics, felts, 
etc. are used mostly as clothing materials. Fibers are spun into strands 
or yarns by spinning processes, and are woven into textiles, knitted into 
knitting goods, packed and adhered into nonwoven fabrics, or otherwise 
processed to produce other fiber products. 
Fibers from which textiles or yarns are prepared are called spinning and 
weaving fibers. Among the spinning and weaving fibers, those prepared into 
the clothing materials are called clothing fibers. Spinning and weaving 
fibers are broadly classified into naturals fibers, such as the fibers of 
vegetable, animal, or mineral origin, and synthetic fibers. 
Synthetic fibers are grouped into inorganic fibers, (e.g. glass or ceramic 
fibers), those in the rayon family, and the synthetic fibers produced from 
substances derived from petroleum (e.g. nylon, polyester, acrylic fibers, 
etc.). 
Fibers of the rayon family are of two types. One is those made from 
regenerated cellulose (wood pulp). Viscose and cuprammonium belong to this 
group. Both are derived from wood pulp dissolved in caustic soda. The 
other type is cellulose acetate fibers which are the reaction products 
(esters) of acetic acid and cellulose. Depending on the degree of 
acetylation cellulose acetate fibers are grouped into diacetate (usually 
called simply "acetate") and triacetate. 
Triacetyl cellulose is produced by the reaction of acetic anhydride and 
cellulose. All three hydroxyl groups in glucose recurring units in 
cellulose are esterified by acetic acid in triacetyl cellulose. Triacetate 
is produced by dissolving the triacetyl cellulose into a suitable solvent, 
typically into a mixed solvent of methylene chloride and methanol, and by 
forcing the solution through spinnerets. Diacetyl cellulose is produced by 
adding water to triacetyl cellulose and heating the mixture to hydrolyze. 
The product is dissolved into acetone and the solution is spun to produce 
diacetate (or acetate). Acetate fabrics are known for their brilliance of 
color and ability to drape well, properties that have made them 
particularly successful as apparel fabrics. Triacetate yarns have many of 
the same properties as diacetate but are particularly known for their 
ability to provide pleat retention in apparel. Short fibers (staples) of 
cellulose acetate are used as filling materials in pillows, mattress pads, 
and quilts and also as filtering agent of cigarettes. They are very 
frequently used blended with other fibers. 
In contrast to natural fibers and synthetic fibers having round, circular 
cross sections, the cross sections of acetate and triacetate fibers are 
concaved circles like leaves of clover. This makes the specific surface 
area of cellulose acetate fibers large. 
Despite the above characteristics, cellulose acetate fibers do not possess 
a far infrared ray emitting, heat-retaining property or a deodorizing 
effect which are demanded of fibers used for sanitary, health-care, or 
medical purposes. 
The present inventors had previously developed a far infrared ray emitting 
body comprising a base material or an inorganic core material having an 
ultrafine inorganic powder with a closely distributed particle size 
adhered on said base or core material, and filed an application for patent 
(U.S. application Ser. No. 07/296,026now U.S. Pat. No. 4,886,972). 
Specifically, the invention comprised a core material having adhered 
thereto an ultrafine powder of a particle size below 500 angstrom of one 
or more compounds selected from the group consisting of alumina hydrate, 
silica hydrate, and the mixture thereof which is chemically produced in an 
aqueous dispersion of said core material. 
The further studies by the inventors were directed to applications of the 
far infrared ray emitting body. As a result the inventors found that by 
the combination of the far infrared ray emitting body and cellulose 
acetate fibers provides the latter with a superior far infrared ray 
emitting, heat-retaining characteristics as well as a superb deodorizing 
effect. This finding has led to the completion of the present invention. 
SUMMARY OF THE INVENTION 
Accordingly an object of this invention is to provide a far infrared ray 
emitting, odor-absorbing material, comprising: 
an inorganic core material having adhered thereto an ultrafine powder of a 
particle size below 500 angstrom of one or more compounds selected from 
the group consisting of alumina hydrate, silica hydrate, and the mixture 
thereof which is chemically produced in an aqueous dispersion of said 
inorganic core material; and 
cellulose acetate fiber in which said inorganic core material having 
adhered thereto an ultrafine powder is filled. 
Another object of the present invention is to provide a far infrared ray 
emitting, odor-absorbing material, comprising: 
cellulose acetate fiber having adhered thereto an ultrafine powder of a 
particle size below 500 angstrom of one or more compounds selected from 
the group consisting of alumina hydrate, silica hydrate, and the mixture 
thereof which is chemically produced in an aqueous dispersion of said 
cellulose acetate fiber. 
A still further object is to provide a far infrared ray emitting, 
odor-absorbing material, comprising: 
(i) cellulose acetate fiber and (ii) one or more inorganic core materials 
selected from the group consisting of naturally occurring clay minerals, 
synthetic inorganic compounds, and synthetic pigments, both (i) and (ii) 
having adhered thereto an ultrafine powder of a particle size below 500 
angstrom of one or more compounds selected from the group consisting of 
alumina hydrate, silica hydrate, and the mixture thereof which is 
chemically produced in an aqueous dispersion of said cellulose acetate 
fiber, and wherein said one or more inorganic core materials having 
adhered thereto said ultrafine powder is filled in said cellulose acetate 
fiber. 
Other objects, features and advantages of the invention will hereinafter 
become more readily apparent from the following description.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS 
The inorganic core material used in this invention may be selected from a 
wide variety of materials. It may be a naturally occurring clay mineral 
such as kaolin, mica, or silicate; a synthetic inorganic compound such as 
alumina or silica; a synthetic pigment such as zirconia or titania. Given 
as more specific examples of the material which can be used as an 
inorganic core material in this invention are thin-layered minerals such 
as kaolin, vermiculite, mica, and the like; spherical particles such as 
spherical silica, beryllium, and the like; fibrous material such as glass 
fibers, ceramic fibers, carbon fibers, zeolite fibers, and the like; 
porous material such as zeolite, diatomaceous earth, and the like; 
pigments, including various oxides, carbonates, sulfates, and nitrates, 
such as zirconia, titanium white, zinc white, barium titanate, and the 
like; and films such as plastic films. 
Ultrafine inorganic particles in this invention are formed in an aqueous 
dispersion of inorganic core material by adding inorganic compounds which 
can produce by reaction such inorganic particles. Preparation of such 
ultrafine inorganic particles is described in the pending U.S. patent 
application Ser. No. 07/152,853 by the present inventors. Specifically, 
particles may be those of alumina hydrate or silica hydrate formed by a 
chemical reaction in an aqueous dispersion of inorganic core materials. A 
typical example of a fine particulate inorganic material is alumina 
hydrate produced by the reaction of aluminum chloride and ammonium 
hydroxide. Other examples of such fine particulate inorganic materials are 
silica, silicate, and the like. For example, to an aqueous solution of 
aluminum chloride an equivalent amount of ammonium hydroxide to neutralize 
the aluminum chloride is added to obtain alumina hydrate. In this 
instance, fine particles of the inorganic material, e.g. alumina hydrate 
in this case, deposit in the aqueous dispersion system. Needle-like 
alumina hydrate deposits and adheres on the surfaces of the suspended 
inorganic core material to form a film, thus producing an ideal uneven 
surface with a large specific surface area which can provide a significant 
far infrared radiation effect. 
Hydrate of alumina or silica takes the form of ultrafine particles having a 
size of 500 angstrom or below, preferably 200 angstrom or below. The 
ultrafine particles remain unagglomerated in the dispersion and adhere on 
and evenly cover the surfaces of inorganic core materials to produce a 
reformed material with a uniform silica or alumina coat. Taking a reformed 
kaolin (a core material) covered with alumina hydrate, as an example, when 
water is eliminated and the material is dried, this material has a very 
uniformly aligned kaolin-alumina hydrate-kaolin structure, which is not 
seen with a mere mixture of kaolin and alumina. It is impossible to 
prepare alumina hydrate particles of a 100 to 200 angstrom size by any 
other means. Sizes on the order of 3,000 angstrom are considered to be an 
ultrafine aluminum particle size according to the present technological 
level. Besides silica and alumina, other inorganic compounds can be used 
as the covering ultrafine powdery material of this invention, so long as 
such compounds can be prepared by the reaction of a soluble acid and a 
soluble alkali. Examples of such compounds are carbonates of calcium, 
magnesium, barium, and the like. 
The far infrared ray emitting, odor-absorbing material of the present 
invention can be prepared by filling the far infrared ray emitting body 
thus prepared into cellulose acetate fibers. As previously mentioned, 
since cellulose acetate fibers have a clover-shaped, concaved circular 
cross section and have a large specific surface area, there are ample 
spaces in the cellulose acetate fibers into which fine particles of far 
infrared ray emitting body can be filled. The fill-out operation can be 
performed by any suitable method. A simple way of filling is to blend 
prescribed amounts of far infrared ray emitting particles and cellulose 
acetate fibers. A ratio of far infrared ray emitting particles and 
cellulose acetate fibers to be blended is usually 1-50 parts by weight of 
far infrared ray emitting particles per 100 parts by weight of cellulose 
acetate fibers, with a preferable range being 1-10 parts by weight of far 
infrared ray emitting particles per 100 parts by weight of cellulose 
acetate fibers. 
The far infrared ray emitting, odor-absorbing material of the present 
invention can also be prepared by using, instead of above-mentioned 
inorganic materials, cellulose acetate fibers as core materials in the 
preparation of the far infrared ray emitting body. In this instance, a 
proportion of ultrafine particles of hydrate of alumina or silica and 
cellulose acetate fibers is 1-50 parts by weight of the former per 100 
parts by weight of the latter. 
Another alternative method of preparing the far infrared ray emitting, 
odor-absorbing material of the present invention is to add cellulose 
acetate fibers to the aqueous dispersion of inorganic core materials in 
which ultrafine particles of alumina hydrate or silica hydrate is formed 
by a chemical reaction. A proportion of the components to be used for 100 
parts by weight of cellulose acetate fibers are 1-100 parts by weight of 
inorganic core materials and 1-50 parts by weight of ultrafine particles 
of alumina hydrate or silica hydrate. 
Any fibers other than cellulose acetate fibers can be used mixed with 
cellulose acetate fibers. 
Materials prepared according to the above procedures have ultrafine 
particles of alumina hydrate or silica hydrate having a large specific 
surface filled in cellulose acetate fibers which also have a large 
specific surface area. The material has excellent far infrared ray 
emitting, odor-absorbing effects and can expand the fields in which 
cellulose acetate fibers can be used. 
Other features of the invention will become apparent in the course of the 
following description of the exemplary embodiments which are given for 
illustration of the invention and are not intended to be limiting thereof. 
EXAMPLE 1 
Ten (10) kg of silicic acid hydrate (manufactured by OK Trading Co., Ltd.) 
having an average particle size of 0.2 .mu.m was dispersed into 10 m.sup.3 
of water. To this dispersion, AlCl.sub.3 was added in such an amount that 
alumina hydrate (as Al.sub.2 O.sub.3.3 H.sub.2 O) of 5 kg could be 
produced. To this, NH.sub.4 OH equivalent to neutralize AlCl.sub.3 was 
added to ensure precipitation and adsorption of alumina hydrate of a 100 
angstrom size on the surface of silicic acid hydrate. Water was removed 
from the product by means of a filter press, followed by drying at 
100.degree. C. The dried substance was pulverized by hammer to obtain a 
far infrared ray emitting body. This body was filled in cellulose acetate 
fiber in an amount of 3% by weight of the cellulose acetate fiber. The 
fiber was spun to obtain 6 denier far infrared ray emitting, 
odor-absorbing yarn of this invention. 
Example 2 
No. 3 water glass containing 3 kg of SiO.sub.2 was added to a dispersion of 
10 kg of TiO.sub.2 (having an average particle size of 0.2 .mu.m) prepared 
in the same manner as in Example 1. To this mixture HCl in an amount 
equivalent to neutralize SiO.sub.2 was added to produce TiO.sub.2 of which 
surface is reformed by SiO.sub.2. An amount of 3% by weight of this 
material was filled in cellulose acetate fiber in the same manner a in 
Example 1. The fiber was spun into 6 denier far infrared ray emitting, 
odor-absorbing yarn of this invention. 
Example 3 
Hundred (100) kg of cellulose acetate fiber was dispersed into 10 m.sup.3 
of water. To this dispersion, AlCl.sub.3 was added in such an amount that 
alumina hydrate (as Al.sub.2 O.sub.3.3H.sub.2 O) of 3 kg could be 
produced. To this, NH.sub.4 OH equivalent to neutralize AlCl.sub.3 was 
added to ensure precipitation and adsorption of alumina hydrate of a 50 
angstrom size on the surface of cellulose acetate fiber. Water was removed 
from the product by means of a filter press, followed by drying at 
100.degree. C. The dried fiber was spun into 6 denier far infrared ray 
emitting, odor-absorbing yarn of this invention. 
Example 4 
No. 3 water glass containing 3 kg of SiO.sub.2 was added to a dispersion of 
100 kg of cellulose acetate fiber prepared in the same manner as in 
Example 3. To this mixture HCl in an amount equivalent to neutralize 
SiO.sub.2 was added to produce cellulose acetate fiber of which surface is 
reformed by film-like SiO.sub.2. The fiber was spun into 6 denier far 
infrared ray emitting, odor-absorbing yarn of this invention. 
Example 5 
Hundred (100) kg of cellulose acetate fiber and 10 kg of silicic acid 
hydrate having an average particle size of 0.2 .mu.m were dispersed into 
10 M.sup.3 of water. To this dispersion, AlCl.sub.3 was added in such an 
amount that alumina hydrate (as Al.sub.2 O.sub.3.3H.sub.2 O) of 3 kg could 
be produced. To this, NH.sub.4 OH equivalent to neutralize AlCl.sub.3 was 
added to ensure precipitation and adsorption of alumina hydrate on the 
surface of cellulose acetate fiber and silicic acid hydrate. Water was 
removed from the product by means of a filter press, followed by drying. 
The dried substance was spun to obtain 6 denier far infrared ray emitting, 
odor-absorbing yarn of this invention. 
Example 6 
The procedure of Example 5 was followed, except that AlCl.sub.3 used was 
such an amount that alumina hydrate (as Al.sub.2 O.sub.3.3H.sub.2 O) of 30 
kg, instead of 3 kg, could be produced and the amount of NH.sub.4 OH used 
was equivalent to neutralize this AlCl.sub.3 to obtain 6 denier far 
infrared ray emitting, odor-absorbing yarn of this invention. 
Example 7 
Ten (10]kg of the dried fiber before spinning prepared in Example 3 was 
blended with 2 kg of polyester fiber and spun into 6 denier far infrared 
ray emitting, odor-absorbing yarn of this invention. 
Example 8 
Ten (10),kg of the dried fiber before spinning prepared in Example 3 was 
blended with 2 kg of silk and spun into 6 denier far infrared ray 
emitting, odor-absorbing yarn of this invention. 
Comparative Example 1 
The same cellulose acetate fiber as used in Example 1, without mixing with 
the far infrared ray emitting body, was spun into 6 denier yarn. 
Comparative Example 2 
The same silicic acid hydrate and cellulose acetate fiber as used in 
Example 1 blended at a ratio of 3:97 and the blend was spun into 6 denier 
yarn. 
Comparative Example 3 
The far infrared ray emitting body produced in Example 1 was blended with 
polyester fiber at a ratio of 3:97 and the blend was spun into 6 denier 
yarn. 
Comparative Example 4 
The far infrared ray emitting body produced in Example 1 was blended with 
polypropylene fiber at a ratio of 3:97 and the blend was spun into 6 
denier yarn. 
Test Examples 
Infrared radiation and NH.sub.3 deodorizing effect were measured on the 
products prepared in Examples 1-8 Comparative Examples 1-4 according to 
the following procedures. 
(1) Infrared Radiation 
An infrared radiation strength of between 2 .mu.m and 30 .mu.m was measured 
by using an infrared spectrometer (Type A-302 manufactured by Nippon 
Bunkokogyo Co., Ltd.) equipped with an auxiliary photometer. The detector 
plotted a comparative value of each sample against a black body which was 
used as a standard. 
The mean integral value of the far infrared radiation strength between 5 to 
15 .mu.m was determined for each sample. Relative strength for each sample 
was then calculated taking the radiation strength at 5-15 .mu.m of the 
sample prepared in Example 1 as 100%. [The Shigaraki Ceramic Research 
Institute (Shiga Prefecture, Japan) Method] 
(2) Deodorizing Effect 
(i) Test samples were prepared by placing the products in a dryer at 
110.degree. C. for 3 hours and then allowing the dried products to cool in 
a desiccator. 
(ii) A 12,150 ml glass container was used for ammonia absorption. A 
magnetic stirrer was provided at the bottom of the container for stirring 
NH.sub.3 gas. 
(iii) A Kitazawa Gas Detector (manufactured by Kitazawa Industry Co., Ltd.) 
was used for measurement of NH.sub.3 gas concentrations. 
(iv) An ammonia absorption test was performed as follows. A specified 
amount of a high concentration ammonia gas was injected to the glass 
container by a microsyringe. After stirring for five minutes the gas 
concentration in the container was measured by the gas detector. This 
procedure was repeated several times. One (1) gram of a sample was then 
placed in the container and the specified amount of a high concentration 
ammonia gas was injected to the glass container by a microsyringe in the 
same manner as above. After stirring for 5 minutes the ammonia 
concentration in the container was measured. Deodorization was calculated 
from the reduced concentration of ammonia gas. 
The results are shown in the following table. Given in the table for 
reference is NH.sub.3 deodorization for coconut shell activated carbon. 
______________________________________ 
Infrared Radiation 
NH.sub.3 
Relative Strength 
Deodorization 
(5 to 15 .mu.m) 
(%) 
______________________________________ 
Example 1 100 50 
Example 2 90 45 
Example 3 120 60 
Example 4 105 55 
Example 5 125 65 
Example 6 130 70 
Example 7 110 50 
Example 8 110 55 
Comparative Example 1 
30 20 
Comparative Example 2 
50 25 
Comparative Example 3 
60 40 
Comparative Example 4 
55 40 
Activated carbon 37 
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The produce of the present invention possesses a high far infrared ray 
emitting, odor-absorbing capability as well as many characteristics 
inherently possessed by fibers, especially by cellulose acetate fibers. 
Thus, the product will enormously expand the utility of cellulose acetate. 
Obviously, numerous modifications and variations of the present invention 
are possible in light of the above teachings. It is therefore to be 
understood that within the scope of the appended claims, the invention may 
be practiced otherwise than as specifically described herein.