CN1063606A - Cigaratte filter - Google Patents

Cigaratte filter Download PDF

Info

Publication number
CN1063606A
CN1063606A CN 91112830 CN91112830A CN1063606A CN 1063606 A CN1063606 A CN 1063606A CN 91112830 CN91112830 CN 91112830 CN 91112830 A CN91112830 A CN 91112830A CN 1063606 A CN1063606 A CN 1063606A
Authority
CN
China
Prior art keywords
matrix
filter
monomer
cellulose fibre
adsorbent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN 91112830
Other languages
Chinese (zh)
Inventor
米·格·沃伦科夫
L·Y·斯尼尔尼科夫
N·N·弗拉索娃
E·Y·卡仆兰
A·E·佩斯敦维奇
R·D·萨法夫
G·A·比理斯基
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of CN1063606A publication Critical patent/CN1063606A/en
Pending legal-status Critical Current

Links

Classifications

    • AHUMAN NECESSITIES
    • A24TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24DCIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
    • A24D3/00Tobacco smoke filters, e.g. filter-tips, filtering inserts; Filters specially adapted for simulated smoking devices; Mouthpieces for cigars or cigarettes
    • A24D3/06Use of materials for tobacco smoke filters
    • A24D3/14Use of materials for tobacco smoke filters of organic materials as additive

Abstract

A kind of cigaratte filter, comprise by acetate fiber, cellulose fibre or-matrix that cellulose acetate fibre is made, matrix is soaked into by adsorbent.This absorbs agent is organic silicon monomer N, N ' two (3-triethoxy-silicane propyl group) thiocarbamide (C 2H 5O) 3Si (CH 2) 3NH-C (S)-NH (CH 2) 3Si (OC 2H 5) 3

Description

Cigaratte filter
The invention belongs to and in the smog of tobacco, eliminate harmful (К О Н ц e р о г e н н ы й) and noxious material, definite, relate to cigarette filter tip; It is used for manufacturing and is with the filter of filter-tip to chew in cigarette industry.
Filter known today is chewed to be equipped with by cellulose acetate fibre and is cooperated the matrix that makes with charcoal, and charcoal can be present in the matrix as mechanical inclusion, also can become the external coating of matrix or simply joins with matrix.The shortcoming that this filter is chewed is that it can not eliminate a series of harmful damaging effects that reach toxic substance in the tobacco smoke at all.
In view of this, just need some effective filtration means, get rid of a large amount of insalubrity compositions in the tobacco smoke as far as possible, can keep original characteristic on its sense organ simultaneously again.
Another cooperates the unfiltered cigarette of making by hydroxyapatite with acetate fiber or active carbon, and is equally also known.The chemical formula of hydroxyapatite can be 3 (Ca 3(PO 4) 2) M(OH) 2It is that a kind of granularity is 2 to 5 microns a material; Consumption in filter is chewed be in the cigarette tobacco weight 0.1~20%.This filter is chewed and be can be made into sheet, cannula-like, nozzle shape or the like.This filter is chewed and can be improved the efficient that is absorbed with harmful substances in the smog of tobacco, as nicotine, tar and carbon monoxide.Yet it can not sponge in the smog of tobacco such as polycyclic aromatic hydrocarbons (PAH) (benzo (a) pyrene; Benzo (g, h, c) perylene; Dibenzo (a, h) anthracene; Dibenzo (a, c) anthracene) and volatile nitrosamine (N '-the nitroso diethylamino; N '-nitrosopyrolidine) etc. harmful and noxious material.
Knownly variously can reduce the unfiltered cigarette that tobacco smoke has toxic action, be that the matrix of being made by acetate fiber, cellulose fibre or acetic acid-cellulose fibre is constituted, and on this matrix, coat material, perhaps soak into it with this material with characterization of adsorption.
Can adopt active carbon, organic or inorganic mercapto alkane sulfonate (salt of cysteine, acetyl cysteine and phthalocyanine) makes to have the material of characterization of adsorption.
These shortcomings with filter tip are, they absorbent material scope always very limited; And chew and be heated along with filter, the formation of toxic compounds can make its degeneration.For example, utilize phthalocyanine to make the catabolites such as derivative that adsorbent can form organic cyanide, ammonia, benzene.
Chewing immediate with the application's filter is that European patent EP-No.89207209.0(is referring to its open No.0351252,91.1.17) filter chew, it has matrix and the adsorbent of being made by acetate fiber, cellulose fibre or acetic acid-cellulose fibre, wherein adsorbent is the complex of ferrous iron and part, said part is the low molecular compound that contains mercaptan, and the iron ion in this compound is not more than 1: 2 with the ratio of ligand molecular number; The amount of absorbent is chewed the 3-13% of gross weight for filter.
Ferrous iron was usually from all FeSO during above-mentioned filter was chewed 4, FeCl 2, Fe(NO 3) 2In molysite, and contain mercaptan degraded what share is the compound that contains single mercaptan (thiol sodium sulphate, half light amino acid, glutathione of having reduced etc.) and the organic compound that contains two mercaptan (diethyl dithiocarbamate, diformazan dithiocarbamate, sodium ethylxanthate and other).
Above-mentioned filter is chewed and can eliminate nitric oxide effectively in the smog of tobacco, but chews equally with the said filter in front, can not reduce in the smog content of harmful and noxious material, such as polycyclic aromatic hydrocarbons (PAH) (benzo (a) pyrene; Benzo (g, h, i) perylene; Dibenzo (a, h) anthracene; Dibenzo (a, c) anthracene), volatile nitrosamine (N '-the nitroso diethylamino; N '-nitrosopyrolidine) and metal (as magnesium, calcium, strontium, copper, lead, arsenic, vanadium, chromium, manganese, iron, cobalt, nickel).
The objective of the invention is to improve the ratio of in the smog of tobacco, removing harmful and noxious material.
Above-mentioned purpose is to realize like this.Unfiltered cigarette of the present invention contains the matrix of being made by acetate fiber, cellulose fibre or acetic acid-cellulose fibre, and matrix has soaked into adsorbent, and said adsorbent uses organosilyl monomer N, N '-two (3-triethoxy-silicane propyl group) thiocarbamide (C 2H 5O) 3Si(CH 2) 3NH-C(S)-NH(CH 2) 3Si(OC 2H 5) 3
Said this filter is chewed, and because of adopting the adsorbent of this recommendation, can guarantee to remove 100% polycyclic aromatic hydrocarbons (PAH), remove and reach 60% volatile nitrosamine and up to 90% metal.
This adsorbent content is preferably 6~15.3% of matrix fiber weight, thereby guarantees to remove in the smog of tobacco the most effectively harmful and poisonous material.
Below, further specify the present invention by description to specific embodiment.
This kind unfiltered cigarette comprises the matrix of being made by acetate fiber, cellulose fibre or acetic acid-cellulose fibre, and matrix soaks into adsorbent.Said adsorbent is organosilyl monomer N, N '-two (3-triethoxy-silicane propyl group) thiocarbamide (C 2H 5O) 3Si(CH 2) 3NH-C(S)-NH(CH 2) 3Si(OC 2H 5) 3
The content of above-mentioned monomer in filter is chewed is 6~15.3% of matrix fiber weight.When content of monomer be lower than matrix fiber weight 6% the time, this monomer soaks into deficiency, the characterization of adsorption variation; If content of monomer is higher than 15.3%, then because of its content surplus, just have in the tobacco of a certain amount of monomer immersion cigarette, make the debase of cigarette.
This monomer and filter are chewed mechanism that matrix material combines and are based on because of above-mentioned monomer and can participate in the condense chemical modification of Dichlorodiphenyl Acetate fiber, cellulose fibre or acetic acid-cellulose fibre matrix of reacted surface base (comprising hydroxyl).This condenses similar by the degenerative treatments of following possibility scheme with the silica dioxide gel of the various trades mark:
At this moment, the surface of acetate fiber, cellulose fibre or acetic acid-cellulose fibre matrix generates one deck polysiloxane polymer chemically combined with it, and the latter has effective characterization of adsorption.This monomer has very high adsorption activity to nitroso compound and polycyclic aromatic hydrocarbons (PAH), this is owing to the reaction center that wherein has as siloxane backbone (С к e л e т), thiocarbonyl group (Т и о к а р б о н и л ь н ы e г р у п п ы) and amino and so on, and each center can both have chemisorption to the harmful or poisonous unit in the smog.
Absorption efficiency to metal depends on the chelation of metal according to two active groups (containing sulphur atom and nitrogen-atoms) of following manner and monomer.
Figure 911128301_IMG2
Under the situation of absorption metal, its characteristic is decided by ionic bond; Adsorption process is carried out according to following manner:
In the process of representative absorption lead and arsenic, be example for example, can be undertaken by following mode with lead:
Figure 911128301_IMG4
Above-mentioned filter is chewed as follows and to be made: will be soaked into 4~10% solution of organic silicon monomer in organic solvent by the matrix that acetate fiber, cellulose fibre or acetic acid-cellulose fibre are made, afterwards drying in addition.
The specific embodiment of the process of manufacturing is chewed in citation the application filter below.
Example 1
Preparation 4% monomer alcoholic solution soaks into filter and chews matrix with the solution that makes that is no less than 13 milliliters, and matrix is made 7.9 millimeters of diameters, long 15 millimeters cylindrical shape by acetate fiber, weighs 110 milligrams, afterwards with gained matrix drying.At this moment, monomer weight is 6% of an acetate fiber weight.The polymerization of monomer takes place in the dry run, and combines with acetate fiber in the matrix.
Example 2
Preparation 7% monomer alcoholic solution is got 13 milliliters and is made solution and soak into filter and chew matrix, and matrix is made 7.9 millimeters of diameters, long 18 millimeters cylindrical shape by acetic acid-cellulose fibre, weighs 137 milligrams, afterwards with gained matrix drying.The polymerization of monomer takes place in the dry run, and combines with acetic acid-cellulose fibre in the matrix.In this case, monomer weight is 10.7% of acetic acid in this matrix-cellulose fibre weight.
Example 3
Preparation 10% monomer alcoholic solution is got 13 milliliters of gained solution and is soaked into filter and chew matrix, and matrix is made 7.9 millimeters of diameters, long 18 millimeters cylindrical shape by cellulose fibre, weighs 130 milligrams, afterwards with gained matrix drying.The polymerization of monomer takes place in the dry run, and combines with cellulose fibre in the matrix; At this moment, the weight of monomer is about 15% of cellulose fibre weight in the matrix.
The cigarette of chewing with above-mentioned filter is tested as follows.
Before the analysis, making all cigarettes earlier is 22 ℃ in temperature, adapts to 48 hours under the condition of relative humidity 60%.According to " International StandartsOrganization International Standard ISO 330; 8.Cigarets-Routine analytical cigarette smoking machine.Definitions and andatandard conditions.Geneva; 1986, P.6 ".The method that provides is done the smoking test on the rotational automatic smoking apparatus of PM20/CS type 20 stations of Germany " Borgwaldt " company.
The suction capacity is 35 milliliters, and 2 seconds duration of suction, the suction frequency is that 1 Cambridge of per minute (к e м б р и д ж с к и й) filter is chewed.
The analysis that polycyclic aromatic hydrocarbons (PAH) content in the smog condensate liquid of tobacco is done is according to Х e с и н а А. Я. and Х и т р о В а И. А and Г e в о р к я н В. the modification method that Р describes in publication carries out; Referring to " applied spectroscopy " magazine (Ж у р н а л п р и к л а д н о й с п e к т р о с к о п и и) 1983; XXXy111; NO.6,P922~933“”(Воэможность количeствeнного опрeдeлeния полицикличeских ароматичeскнх углeводородов в загрязнeниях окружаюшeй чeловeка срeды на основe квазилинeйчатых спeктров люминeсцeнции и возбуждeния)。 Chew the condensate liquid that (92 millimeters of diameters) goes up 10 smoke from cigarettes of suction a Cambridge filter, the ultra sonic bath (y л ъ т р а з в у к о в а я б а н я) that employing power is 60 watts, per 30 minutes 2 times extracts with benzene, and is concentrated into 5 milliliters with rotary evaporator under, 35 ℃ of of of of of of .In hexane-benzene series system (ratio is 3:1), utilize thin-layered chromatography 1 milliliter of extract to be separated with unfixed aluminium oxide thin layer thereupon; The composition of the path analysis polycyclic aromatic hydrocarbons (PAH) by almost fluorescence spectrum record, this is under liquid nitrogen temperature, this polycyclic aromatic hydrocarbons (PAH) of selective exitation carries out on Hitachi's board spectrofluorimeter.
According to publication " The cadmium; nickel and lead content of tobacco and cigarette smoke " (Westcolt D., Sprincer D.) Beifr.Tabak-porsch, 1974, v.7, N 4, PP.217-221, Jenkins R. " Occurrence of selected metals in cigarette tobacco and smoke.Environmental carcinogens selected methods of analysis ", Lyon, 1986, IARC Sci.Publ.No.71, v.8, pp.129-138.Described in modification method determine tenor in the tobacco smoke condensate liquid.In this case, atomic absorption method is changed into the plasma emission method.Analysis is carried out on France's " Jobin-Ivon " JV-48 type plasma emission spectrometer, usefulness be that diameter is that 44 millimeters Cambridge filter is chewed, inhaled 5 cigarettes through it.
Determine volatile n-nitrosamine, the content of N-nitroso diethylamino and П-nitrosopyrolidine according to the modification method that international cancer research institution is introduced.Referring to " IARC Scientific Publications No.45, Environmental carcinogens selected methods of analysis.Vol.6, N-Nitrozo Compounds ", Lyon, 1986, pp.69-103.
Table 1,2,3 has been listed the result of above-mentioned check, and data wherein are the average that the filter of doing matrix with acetate fiber, cellulose fibre or acetic acid-cellulose fibre is chewed.
Can find out that from table 1,2,3 filter of the present invention is chewed and can intercept and capture the harmful and noxious material such as polycyclic aromatic hydrocarbons (PAH), volatile nitrosamine and metal etc. effectively in the smog of tobacco.In addition, it is nontoxic that the organic silicon monomer that is used as adsorbent is chewed in this filter, and the matrix that soaks into this monomer is stable from the time, and when being heated to 240 ℃ the performance of maintenance itself still.
Table 1
By having through N, the unfiltered cigarette of the matrix that N '-two (3-triethoxy-silicane propyl group) thiocarbamide soaks into (content be respectively this matrix weight 6%, 10.7% and 15.3%) is intercepted and captured the efficient of polycyclic aromatic hydrocarbons (PAH) in the smoke from cigarette main flow.
Figure 911128301_IMG5
Table two
By having through N, the unfiltered cigarette of the matrix that N '-two (3-triethoxy-silicane propyl group) thiocarbamide soaks into (content be respectively this matrix weight 6%, 10.7% and 15.3%) is intercepted and captured the efficient of metal in the smoke from cigarette main flow
Tested cigarette 15.3% 10.7%
Metal Mcg/ml
Ca Ni CN Zn Mg Al Cr V Cd Sr Co Ti Pb Mn Fe As 5.15±1.54 0.21±0.08 0.18±0.025 1.95±0.3 0.81±0.27 1.53±0.15 0.145±0.015 0.053±0.021 0.044±0.01 0.063±0.013 0.12±0.06 0.45±0.078 0.063±0.012 0.051±0.012 2.2±1.1 0.48±0.23 0.9±0.23 0.05±0.01 0.043±6E-3 0.42±0.09 0.15±0.03 0.48±0.01 0.039±6E-3 5.75E-3±1.05E-3 5.25E-3±9.5E-4 0.014±2E-3 0.02±2E-3 0.16±0.033 —— 0.028±3.45E-3 0.39±0.095 —— 1.66±0.15 0.038±1E-3 0.059±1.5E-3 0.49±0.05 0.24±0.07 0.42±0.06 0.042±0.001 0.019±0 0.013±1E-3 0.012±2E-3 0.025±1E-3 0.14±0.01 0.05±0.06 0.03±1E-3 0.4±0.1 0.03±0.001
Table two (continuing)
6% efficient % metal 15.3% 10.7% 6%
Ca?????2.41±0.32?????????73.1??????????72.0?????????69.7
Ni?????0.026±0.01????????89.2??????????78.0?????????66.0
CN?????0.075±0.12????????88.1??????????71.3?????????54.5
Zn?????0.555±0.23????????77.8??????????66.0?????????54.0
Mg?????0.33±0.08?????????83.3??????????79.0?????????75.0
Al?????0.36±0.06?????????64.4??????????68.9?????????73.3
Cr?????0.044±0.01????????100???????????62.7?????????25.4
V??????0.018±0???????????45.1??????????44.0?????????43.1
Cd?????0.02±2E-3?????????82.3??????????81.9?????????81.4
Sr?????0.029±5E-3????????100???????????88.4?????????76.4
Co?????0.03±7.5E-3???????82.5??????????67.9?????????53.2
Ti?????0.12±0.05?????????76.2??????????81.9?????????87.6
Pb?????0.047±4.5E-3??????76.1??????????67.2?????????58.3
Mn?????0.029±5E-3????????78.4??????????75.2?????????71.5
Fe?????0.41±0.19?????????81.5??????????70.0?????????59.2
As 0.113±0.06 68.6 72.3 76.4
Table 3.
By having through N, the unfiltered cigarette of the matrix that N '-two (3-triethoxy-silicane propyl group) thiocarbamide soaks into (content be respectively this matrix weight 6%, 10.7% and 15.3%) is intercepted and captured the efficient of volatile nitrosamine in the smoke from cigarette main flow
Tested cigarette 10% 7%
The title nanogram/
N '-nitroso diethylamino 2.19 ± 0.07 0.82 ± 0.09 1.06 ± 0.07
N '-nitrosopyrolidine 5.53 ± 0.61 4.18 ± 0 3.44 ± 0.08
4%Efficient %
Title 10% 7% 4%
N '-nitroso diethylamino 1.29 ± 0.035 62.6 52 41.4
N '-nitrosopyrolidine 2.7 ± 0.1 24.4 37.8 51.2

Claims (2)

1, a kind of unfiltered cigarette comprises the matrix of being made by acetate fiber, cellulose fibre or cellulose acetate fibre, and matrix is soaked into by adsorbent, it is characterized in that: that adsorbent adopts is organic silicon monomer N, N ' two (3-triethoxy-silicane propyl group) thiocarbamide
2, a kind ofly chew according to the described filter of claim 1, it is characterized in that: the content of adsorbent is 6~15.3% of matrix weight.
CN 91112830 1990-12-25 1991-12-25 Cigaratte filter Pending CN1063606A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SU4896031 1990-12-25
SU904896031A RU1797481C (en) 1990-12-25 1990-12-25 Filter for cigarettes

Publications (1)

Publication Number Publication Date
CN1063606A true CN1063606A (en) 1992-08-19

Family

ID=21551855

Family Applications (1)

Application Number Title Priority Date Filing Date
CN 91112830 Pending CN1063606A (en) 1990-12-25 1991-12-25 Cigaratte filter

Country Status (4)

Country Link
EP (1) EP0493026A3 (en)
JP (1) JPH06121664A (en)
CN (1) CN1063606A (en)
RU (1) RU1797481C (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100333670C (en) * 2004-10-15 2007-08-29 湖南中烟工业公司 Inorganic spinning additive and its application method
CN102933296A (en) * 2010-06-08 2013-02-13 3M创新有限公司 Solid phase extraction media

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2010545C1 (en) * 1992-04-22 1994-04-15 Товарищество с ограниченной ответственностью "Сфинкс" Cigarette filter
ES2074962B1 (en) * 1993-12-23 1996-05-16 Lopez Acedo Fernandez Shaw Cec LIQUID FILTER FOR RETENTION OF TOXIC SUBSTANCES IN TOBACCO, PROCEDURE FOR ITS PREPARATION AND APPLICATIONS.
NO306492B1 (en) * 1998-06-29 1999-11-15 Mohammad Azam Mansoor Cigarette filter containing chemical compounds
EP2138214A1 (en) * 2008-06-27 2009-12-30 British American Tobacco (Investments) Limited A method for removing polycyclic aromatic hydrocarbons
JP2011021869A (en) * 2009-07-18 2011-02-03 Nisshin Denki:Kk Ventilated cigarette smoke detoxification device
CN104525126B (en) * 2014-12-18 2017-12-05 湖北中烟工业有限责任公司 Biopolyamines modified graphite alkenes sorbing material and its preparation method and application

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3662765A (en) * 1970-11-27 1972-05-16 Gen Electric Smoke filter
BR8903470A (en) * 1988-07-15 1990-03-06 Mo Tabachnaya Fabrika Yava COMPOSITION AND PROCESS FOR ABSORPTION OF NITROGEN OXIDE FROM TOBACCO SMOKE, FILTER TO PURIFY TOBACCO SMOKE FROM NITROGEN OXIDE AND IMPREGNATION PROCESS FROM A BASE OF A FILTER

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100333670C (en) * 2004-10-15 2007-08-29 湖南中烟工业公司 Inorganic spinning additive and its application method
CN102933296A (en) * 2010-06-08 2013-02-13 3M创新有限公司 Solid phase extraction media

Also Published As

Publication number Publication date
EP0493026A2 (en) 1992-07-01
RU1797481C (en) 1993-02-23
JPH06121664A (en) 1994-05-06
EP0493026A3 (en) 1992-12-16

Similar Documents

Publication Publication Date Title
KR920002444B1 (en) Highly efficient tobacco smoke filter
CN106076283B (en) A kind of nano-cellulose/poly-dopamine hydrogel adsorbent and the preparation method and application thereof
JP2004520818A (en) Methods and products for removing carcinogens from tobacco smoke
US11000824B2 (en) Treated activated carbon for removal of airborne organic and inorganic contaminants
RU2010545C1 (en) Cigarette filter
Pitts Jr et al. Factors influencing the reactivity of polycyclic aromatic hydrocarbons adsorbed on filters and ambient POM with ozone
CN1063606A (en) Cigaratte filter
JPH06343448A (en) Tobacco smoke emission filter and method of sucking tar, nicotine and toxic gas into said filter
JPWO2004091753A1 (en) Hazardous substance removal method and hazardous substance removal filter
CN1046842A (en) From tobacco smoke, absorb the component of nitrogen oxide,, use the filter of this component cleaning tobacco smoke and the method for soaking into filter matrix with this component with the method for this component absorption nitrogen oxide
CN102885395B (en) A kind of method of tobacco sheets by paper making method harm reduction upgrading
JP2008532530A (en) Instant addition solution for cigarette filter, its production method and method of use
JP2006034127A (en) Cigarette filter with high selectively removing ability of formaldehydes
CN108136311B (en) Treated activated carbon for removal of organic and inorganic contaminants from air
CN101316524A (en) Cigarette filters
CN1596783A (en) Absorption additive chitosan-Cu compound used in cigarette filter tip and its preparation method
JP2000005544A (en) Deodorant and deodorizing method
RU2330592C1 (en) Filter for cigarettes
JPH02180634A (en) Porous deodorizing filter
CN110907235A (en) Method for collecting and detecting phenol flavor components in cigarette mainstream smoke
RU2180261C1 (en) Method of cleaning waste gases from bad smelling agents
KR20090096882A (en) A free radical removal composition comprising naphthoquinone-pigment and extract of mountain panax ginseng c. a. mayer adventitous roots and cigarette comprising the composition
RU2113810C1 (en) Filter for cigarettes
Mayfield et al. Wool Cigarette Filters Part II: Modifications to Promote the Selective Removal of Biologically Active Vapour Phase Components
JP3856049B2 (en) Air cleaning filter material

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C01 Deemed withdrawal of patent application (patent law 1993)
WD01 Invention patent application deemed withdrawn after publication