CN1123576C - Low substitution degree hydroxy-propyl cellulose - Google Patents
Low substitution degree hydroxy-propyl cellulose Download PDFInfo
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- CN1123576C CN1123576C CN00100989A CN00100989A CN1123576C CN 1123576 C CN1123576 C CN 1123576C CN 00100989 A CN00100989 A CN 00100989A CN 00100989 A CN00100989 A CN 00100989A CN 1123576 C CN1123576 C CN 1123576C
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
- C08B11/00—Preparation of cellulose ethers
- C08B11/02—Alkyl or cycloalkyl ethers
- C08B11/04—Alkyl or cycloalkyl ethers with substituted hydrocarbon radicals
- C08B11/08—Alkyl or cycloalkyl ethers with substituted hydrocarbon radicals with hydroxylated hydrocarbon radicals; Esters, ethers, or acetals thereof
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Abstract
The present invention provides a hydroxypropylcellulose having a low substitution degree, capable of giving a solution state which is excellent in transparency and stable in a wide temperature range, by controlling the amount of the substituted hydroxypropyl groups. This hydroxypropylcellulose having a low substitution degree has an average substituted hydroxypropyl group content of 0.1-0.4 mole per glucose unit. Therein, the glucose units each substituted by two or more moles of the hydroxypropyl groups are contained in an amount of <=5% based on the number of all the glucose units, and the transmittancy of a solution containing the hydroxypropylcellulose in a concentration of 2 wt.% in a 10 wt.% sodium hydroxide aqueous solution is >=90% at 10-50 DEG C.
Description
The present invention relates to alkaline aqueous solution is had the low degree of substitution hydroxypropyl cellulose of the stable solvability and the higher solution transparency in wide temperature range.
Hydroxypropylcellulose is the cellulosic structure monomer---glucose monomer (C
6H
10O
5) the nonionic polymkeric substance that obtained by the hydroxypropyl etherificate of 3 hydroxyls because it has all useful characteristics and can be widely used in multiple use.
The characteristic of hydroxypropylcellulose is very different according to its hydroxypropyl replacement amount.As the method for expressing of substitution value, the method for representing with substituent average replacement mole number (MS) on each glucose monomer is the most general, and this method has obtained using widely.
The hydroxypropylcellulose that substitution value is high, it is easily molten to cold water promptly on average to replace mole number and be 2～3 hydroxypropylcellulose, insoluble to hot water, dissolves in organic solvents such as alcohol.The hydroxypropylcellulose that substitution value is low has water insoluble or organic solvent, contacts the back swelling with water, is dissolved in the character of alkaline aqueous solutions such as alkaline hydrated oxide.
Because these character, the low degree of substitution Mierocrystalline cellulose can be as the tackifier of the disintegrating agent of medicine, tackiness agent, basic solution.
As low degree of substitution hydroxypropyl cellulose, special public clear 48-38858 communique, special public clear 57-53100 communique etc. discloses the preparation method that the average replacement mole number of hydroxypropyl on each glucose monomer is 0.05～1.0 hydroxypropylcellulose.But though adopt the material of these method preparations to dissolve in the alkaline aqueous solution, owing to contain more insoluble composition, the transparency of its solution is low.In addition, bigger owing to varying with temperature for its solvability of alkaline aqueous solution, have the problem that its working conditions is restricted in requiring the purposes of stability of solution.
Low degree of substitution hydroxypropyl cellulose is subjected to the influence of hydroxypropyl substitution value bigger to the solvability of alkaline aqueous solution.In order to obtain having the low degree of substitution hydroxypropyl cellulose of good solubility, the importantly management of hydroxypropyl replacement amount, i.e. its each structure monomer---average replacement mole number and the hydroxypropyl of hydroxypropyl replaces the ratio of the different replacement body of mole number on the glucose monomer.
Thus, by the replacement amount of control hydroxypropyl, a kind of low degree of substitution hydroxypropyl cellulose wish to appear, its solution transparent good, can in wide temperature range, keep stable solution state, still up to the present also do not have well-content product.
The inventor has carried out concentrated research in order to solve above-mentioned problem, found that each glucose monomer (C
6H
10O
5) going up hydroxypropyl, on average to replace mole number be in 0.1～0.4 the low degree of substitution hydroxypropyl cellulose, low degree of substitution hydroxypropyl cellulose with following characteristics has than high transparent when being dissolved in basic solution, solution state is stable in wide temperature range, and above-mentioned feature is: the glucose monomer number that is replaced by hydroxypropyl more than 2 moles adds up to below 5% with respect to glucose monomer; And to be dissolved in solution that 10 weight % aqueous sodium hydroxide solutions the obtain transparence 10 ℃～50 ℃ the time with 2 weight % concentration be more than 90%, thereby finished the present invention.
Low degree of substitution hydroxypropyl cellulose of the present invention was compared with former low degree of substitution hydroxypropyl cellulose, because the transparency is good when being dissolved in alkaline aqueous solution, its solvability does not vary with temperature, so a kind of solution stable in wide temperature range can be provided, therefore can be used for the multiple uses such as tackifier of alkaline aqueous solution.
Below illustrate in greater detail the present invention.
The average replacement mole number of hydroxypropyl is 0.1～0.4 on each glucose monomer of low degree of substitution hydroxypropyl cellulose of the present invention.The average mole number that replaces is lower than at 0.1 o'clock, when being dissolved in basic solution because to have insolubles, solution be opaque; Surpass at 0.4 o'clock, occur white opacity in the solution, solution also is opaque.
In addition, to replace mole number be that the number of the replacement body (glucose monomer) more than 2 adds up to below 5% with respect to glucose monomer to the preferred hydroxypropyl of low degree of substitution hydroxypropyl cellulose of the present invention.If being the ratio of the replacement body more than 2, hydroxypropyl replacement mole number surpasses 5%, same as described above, and white opacity appears in the solution, become opaque solution.This is owing to replace mole number be that the ratio increase of the replacement body 2 or more makes that the solution forfeiture is transparent to be caused with respect to low do not replace body and the hydroxypropyl of basic solution solvability.
The preparation of low degree of substitution hydroxypropyl cellulose of the present invention is that Mierocrystalline cellulose and alkaline hydrated oxide are reacted in the fs, generates alkali cellulose.
As the compound method of alkali cellulose, proper is after former slip is flooded in the alkaline hydrated oxide aqueous solution, and the remaining alkaline hydrated oxide aqueous solution is removed in extruding, obtains the method that required alkali cellulose is formed.
As the Mierocrystalline cellulose of raw material for example wood pulp, cotton linter pulp etc., can use flaky material, be ground into pulverous material, unqualified to its shape.
In addition, the alkaline hydrated oxide aqueous solution can use the aqueous solution of sodium hydroxide, potassium hydroxide, lithium hydroxide etc., preferred sodium hydroxide.
Preferred 20～45 weight % of the concentration of the alkaline hydrated oxide aqueous solution, preferred especially 30～40 weight %.If the concentration of the alkaline hydrated oxide aqueous solution is lower than 20 weight %, then cellulosic swelling is insufficient, can not make it activation, causes next step etherification reaction fully not carry out.On the other hand, if surpass 45 weight %, the composition heterogeneity of Pei Zhi alkali cellulose then changes with temperature to the solvability of basic solution, and the physical properties of solution varies with temperature greatly.
The preparation method of alkali cellulose, the method that also has mixed pulp and the alkaline hydrated oxide aqueous solution in dispersion medium such as organic solvent in addition, and the method for the alkaline hydrated oxide aqueous solution of on slurry, directly spraying etc., but compare with the alkali cellulose that dipping in the alkaline hydrated oxide aqueous solution obtains, it forms heterogeneity, is unsuitable for the preparation of the purpose product low degree of substitution hydroxypropyl cellulose of basic solution favorable solubility (promptly).
Alkaline hydrated oxide in the alkali cellulose plays an important role as the catalyzer to propylene oxide reaction, plays the activation that improves cellulose reactive simultaneously.On the other hand, moisture meeting and propylene oxide reaction in the alkali cellulose, the impurity that generation must be removed from product, this be we do not wish to take place.
Therefore, in order effectively to prepare low degree of substitution hydroxypropyl cellulose, when the preparation alkali cellulose, be necessary to control the amount and the amount of moisture of alkali cellulose neutral and alkali oxyhydroxide by alkali cellulose and propylene oxide reaction.
When preparation low degree of substitution hydroxypropyl cellulose of the present invention, the amount of the alkaline hydrated oxide in the alkali cellulose and amount of moisture with respect to cellulosic weight ratio are: the amount 0.1～1.0 of alkaline hydrated oxide, preferred especially 0.2～0.8, amount of moisture 0.1～2.0, preferred especially 0.3～1.0.
If the amount of alkaline hydrated oxide and amount of moisture are lower than above-mentioned scope with respect to cellulosic weight ratio, then reaction can not fully be carried out; On the other hand, if the amount of alkaline hydrated oxide and amount of moisture are higher than above-mentioned scope, propylene oxide and water reaction generate more objectionable, can not get the material that the hydroxypropyl substitution value reaches regulation, for the impurity of removing the side reaction generation need expend very big work, therefore all being difficult to control hydroxypropyl replacement amount in any occasion reaches regulation.
Therefore, when preparation low degree of substitution hydroxypropyl cellulose of the present invention, after the method for preparation alkali cellulose was preferably flooded raw material paper pulp in fs in the alkaline hydrated oxide aqueous solution, the remaining alkaline hydrated oxide aqueous solution was removed in extruding, obtains the method that required alkali cellulose is formed.
When preparation low degree of substitution hydroxypropyl cellulose of the present invention, subordinate phase is that alkali cellulose and propylene oxide thorough mixing are made it to react, temperature of reaction is 30～80 ℃, and preferred especially 40～70 ℃, adding with respect to the Mierocrystalline cellulose mol ratio is that 0.15～2.0 propylene oxide reacts.
If temperature of reaction is lower than 30 ℃, reaction is carried out extremely slow, so because long reaction time is impracticable; If be higher than 80 ℃, hydroxypropyl replaces the ratio increase that mole number is the polysubstituted body more than 2 in the generation hydroxypropylcellulose, the perhaps impurity level increase of propylene oxide and water reaction generation, thereby not preferred.
If the addition of propylene oxide goes beyond the scope, then can not get the material that the hydroxypropyl substitution value reaches regulation.
As the method for adding propylene oxide, can adopt method that the propylene oxide with specified amount once all adds, divide for several times any one method such as adding continuously.In addition, also can use with the active little organic solvent of propylene oxide reaction as dispersion medium, implement this reaction.
Reaction product of the present invention contains the impurity of alkaline hydrated oxide or propylene oxide and water reaction generation etc., adopts known method to be easy to make with extra care, and can obtain low degree of substitution hydroxypropyl cellulose free from foreign meter, that purity is high.
Adopt the replacement body of the low degree of substitution hydroxypropyl cellulose that the present invention obtains to form and to obtain according to known method, Carbhydro.Res.vol.170 for example, the p.207 method of (1987) record etc.
Replace the measuring method that body is formed, for example make it under the alkali existence condition to react, will obtain low degree of substitution hydroxypropyl cellulose behind the free HM with methylating agent such as methyl iodide, use acid decomposition such as trifluoracetic acid after, reduction obtains glucitol derivative.Handle with vapor-phase chromatography using acetic anhydride etc. to carry out the material that acetylize obtains, can separate hydroxypropyl and replace number and the different material of the position of substitution, thereby obtain separately ratio.
The transparency of the low degree of substitution hydroxypropyl cellulose that employing the present invention obtains can be judged according to transparence.Transparence is meant that the light transmission rate of the Purified Water of measuring with photoelectric colorimeter is at 100 o'clock, under the same conditions the transmittance of low degree of substitution hydroxypropyl cellulose solution.Its measuring method has concrete record in an embodiment.
Below in conjunction with embodiment and the present invention of comparative example more detailed description, but the present invention is not limited to the record of these embodiment.(embodiment 1)
(1) preparation of low degree of substitution hydroxypropyl cellulose
Flaky paper pulp 100 weight parts be impregnated in the 40 weight % aqueous sodium hydroxide solutions, make raw material paper pulp absorb aqueous sodium hydroxide solution after, apply 3kg/cm
2Pressure extrusion remove remaining aqueous sodium hydroxide solution, alkaline hydrated oxide is adjusted to 0.55 with respect to cellulosic weight ratio, moisture is adjusted to 0.90 with respect to cellulosic weight ratio.The alkali cellulose that makes is chopped up, be encased in the pressurized reactor that inside possesses stirrer, in reactor, feed after nitrogen fully replaces, add propylene oxide 24 weight parts (is 0.67 to cellulosic mol ratio), 50 ℃ of reactions 3 hours down.
With in the acetic acid and after the residual NaOH, with 50～60 ℃ warm water washing reaction product.80 ℃ of air seasonings, obtain colorless solid shape low degree of substitution hydroxypropyl cellulose 108 weight parts.It is 0.26 that the hydroxypropyl that adopts the Zeisel method to obtain on average replaces mole number.
(2) replacing body forms
Low degree of substitution hydroxypropyl cellulose 3 weight parts that (1) is obtained are dissolved in dimethyl sulfoxide (DMSO) 250 weight parts.After in this solution, adding Powdered sodium hydroxide 30 weight parts, add methyl iodide 100 weight parts while stirring, reacted 4 hours down at 60 ℃.Reaction product is injected in the hot water of 10000 weight parts, makes it to separate out methylated hydroxypropyl cellulose.The material that recovery is separated out, drying is 6 hours under 70 ℃.In methylated hydroxypropyl cellulose 5 weight parts that obtain, add 2mol% trifluoroacetic acid aqueous solution 300 weight parts, after 3 hours, regulate pH7 with barium carbonate 120 ℃ of processing.After wherein adding sodium borohydride 1.5 weight parts, at room temperature stirring 1 hour, make it to solidify 100 ℃ of following evaporation dryings.In residue, add acetic anhydride 100 weight parts, pyridine 200 weight parts, handled 3 hours down at 120 ℃.Add entry 500 weight parts after the cooling, with tetracol phenixin 50 weight parts extraction 2 times.The evaporation tetracol phenixin adopts GC to analyze residue.By GC peak area analytically, obtaining hydroxypropyl, to replace mole number be total ratio of polysubstituted body more than 2 and the proportion of composing that does not replace body, and the result is as shown in table 1.
(3) physical properties of solution and solid physical properties
The low degree of substitution hydroxypropyl cellulose that (1) is obtained is dissolved in 10 weight % aqueous sodium hydroxide solutions, makes the concentration of low degree of substitution hydroxypropyl cellulose reach 2 weight %.Use Brookfield viscometer to measure the viscosity of the solution of preparing when solvent temperature becomes 10 ℃, 30 ℃, 50 ℃, use the visible light transmissivity of photoelectric colorimeter (5E type) mensuration with respect to blank (water).Above measurement result is as shown in table 1.The basic solution of this product has than high transparent in wide temperature range.(embodiment 2)
Remove pulverous raw material paper pulp 100 weight parts be impregnated in 45 weight % aqueous sodium hydroxide solutions, the extruding of exerting pressure, the preparation alkaline hydrated oxide is 0.46 with respect to cellulosic weight ratio, moisture is 0.64 alkali cellulose with respect to cellulosic weight ratio.Add propylene oxide 32 weight parts (is 0.89 mole with respect to cellulosic mol ratio), reacted 2 hours down, adopt the method identical to be prepared in addition, obtain low degree of substitution hydroxypropyl cellulose 112 weight parts with embodiment 1 it (1) at 75～80 ℃.The average replacement mole number of hydroxypropyl is 0.39.
The replacement body of this material is formed and the physical properties of solution adopts the method identical with embodiment 1 to obtain, and the result is as shown in table 1.The basic solution of this product has than high transparent in wide temperature range.(embodiment 3)
Remove flaky raw material paper pulp 100 weight parts be impregnated in the 25 weight % aqueous sodium hydroxide solutions, the extruding of exerting pressure, preparing alkaline hydrated oxide is 0.20 with respect to cellulosic weight ratio, moisture is 0.67 alkali cellulose with respect to cellulosic weight ratio.Add propylene oxide 8.7 weight parts (is 0.24 mole with respect to cellulosic mol ratio), reacted 4 hours down, adopt the method identical to be prepared in addition, obtain low degree of substitution hydroxypropyl cellulose 103 weight parts with embodiment 1 it (1) at 35～40 ℃.The average replacement mole number of hydroxypropyl is 0.11.
The replacement body of this material is formed and the physical properties of solution adopts the method identical with embodiment 1 to obtain, and the result is as shown in table 1.The basic solution of this product has than high transparent in wide temperature range.(comparative example 1)
The amount that adds except that propylene oxide is 45 weight parts (is 1.26 with respect to cellulosic mol ratio), to adopt the method identical with embodiment 1 it (1) to be prepared, and obtains low degree of substitution hydroxypropyl cellulose 115 weight parts.The average replacement mole number of hydroxypropyl is 0.45.
The replacement body of this material is formed and the physical properties of solution adopts the method identical with embodiment 1 to obtain, and the result is as shown in table 1.The basic solution of this product muddiness that is white in color, the transparency is low.(comparative example 2)
Except that temperature of reaction be 85～100 ℃ the reaction 1.5 hours, adopt the method identical to be prepared with embodiment 1 it (1), obtain low degree of substitution hydroxypropyl cellulose 106 weight parts.The average replacement mole number 0.24 of hydroxypropyl.
The replacement body of this material is formed and the physical properties of solution adopts the method identical with embodiment 1 to obtain, and the result is as shown in table 1.The basic solution of this product muddiness that is white in color, the transparency is low.(comparative example 3)
Flaky paper pulp 100 weight parts be impregnated in the 8 weight % aqueous sodium hydroxide solutions, the extruding of exerting pressure, the preparation alkaline hydrated oxide is 0.08 with respect to cellulosic weight ratio, moisture is 1.0 alkali cellulose with respect to cellulosic weight ratio, adopt the method identical to be prepared in addition, obtain low degree of substitution hydroxypropyl cellulose 101 weight parts with embodiment 2.The average replacement mole number of hydroxypropyl is 0.06.
The replacement body of this material is formed and the physical properties of solution adopts the method identical with embodiment 1 to obtain, and the result is as shown in table 1.This product is almost insoluble with respect to aqueous sodium hydroxide solution.Table 1
1) " substitution value " adopts the Zeisel method to obtain.The average mole number that replaces of " MS " expression.2) as " replacing body forms ",
| Substitution value 1) (MS) | Replacing body forms 2) | The physical properties of solution 3) | ||||||
| Do not replace body (%) | One replaces body (%) | Polysubstituted body (%) | Transparence (%) 4) | Viscosity 5) (mPa·s) | ||||
| 10℃ | 30℃ | 50℃ | ||||||
| Embodiment 1 embodiment 2 embodiment 3 comparative examples 1 comparative example 2 | 0.26 0.39 0.11 0.45 0.24 | 76.4 63.7 89.2 61.5 83 | 21.4 33.7 10.2 32.9 13.1 | 2.2 2.6 0.6 5.6 5.1 | 100 100 98 75 88 | 98 98 95 66 76 | 94 93 93 41 55 | 182 139 210 145 168 |
| Comparative example 3 | 0.06 | 94.1 | 5.8 | 0.1 | Do not dissolve | |||
" do not replace body " and represent that hydroxypropyl replacement mole number is 0 replacement body,
" one replaces body " expression hydroxypropyl replacement mole number is 1 replacement body,
" polysubstituted body " expression hydroxypropyl replacement mole number is all the replacement bodies more than 2.
The GC condition determination is as follows:
Device: Hewlett Packard company produces 5980 SERIES II gas chromatographs
Post: 5% phenmethyl silane 0.2mm φ * 25m,
Sample: 1 μ l,
Sampler and wave-detector temperature: 250 ℃
Thermostat temperature: 170 are warmed up to 300 ℃ of (heat-up rate are 2.5 ℃/minute) 3) " physical properties of solution " be that the concentration of hydroxypropylcellulose with 2 weight % is dissolved in the 10 weight % aqueous sodium hydroxide solutions, uses this solution to measure.4) " transparence " is to use photoelectric colorimeter 5E type, 20mm colorimetric pool, visible light to measure.5) " viscosity " is to use Brookfield viscometer to measure under 10 ℃.
Claims (1)
1. the average replacement mole number of hydroxypropyl is 0.1～0.4 low degree of substitution hydroxypropyl cellulose on each glucose monomer, described low degree of substitution hydroxypropyl cellulose, the glucose monomer number that is replaced by hydroxypropyl more than 2 moles adds up to below 5% with respect to glucose monomer, and this low degree of substitution hydroxypropyl cellulose is dissolved in the transparence of solution in the time of 10 ℃～50 ℃ that obtains in the 10 weight % aqueous sodium hydroxide solutions with the concentration of 2 weight % be more than 90%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP008636/1999 | 1999-01-18 | ||
| JP00863699A JP3572213B2 (en) | 1999-01-18 | 1999-01-18 | Low substituted hydroxypropylcellulose |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1261603A CN1261603A (en) | 2000-08-02 |
| CN1123576C true CN1123576C (en) | 2003-10-08 |
Family
ID=11698446
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN00100989A Expired - Lifetime CN1123576C (en) | 1999-01-18 | 2000-01-17 | Low substitution degree hydroxy-propyl cellulose |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP3572213B2 (en) |
| KR (1) | KR100464749B1 (en) |
| CN (1) | CN1123576C (en) |
| TW (1) | TWI224111B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000327701A (en) * | 1999-05-18 | 2000-11-28 | Shin Etsu Chem Co Ltd | Hydroxypropyl cellulose having low degree of substitution and solid formulation |
| JP2002207030A (en) * | 2001-01-09 | 2002-07-26 | Nippon Soda Co Ltd | Method and apparatus for measuring content of hydroxypropyl group |
| KR100525252B1 (en) * | 2003-12-16 | 2005-10-31 | 삼성정밀화학 주식회사 | Method for preparation of fine powdered Cellulose ethers |
| JP5377816B2 (en) * | 2005-06-16 | 2013-12-25 | 信越化学工業株式会社 | Method for producing cellulose ether |
| GB0516154D0 (en) * | 2005-08-05 | 2005-09-14 | Ntnu Technology Transfer As | Carbon membranes |
| JP5089287B2 (en) * | 2006-08-08 | 2012-12-05 | 信越化学工業株式会社 | Method for producing low substituted hydroxypropylcellulose powder |
| CN101555285B (en) * | 2008-12-19 | 2010-12-01 | 浙江中维药业有限公司 | Preparation method of low-substituted hydroxypropyl cellulose |
| JP5586575B2 (en) * | 2009-02-20 | 2014-09-10 | 住友精化株式会社 | Method for producing hydroxyalkyl cellulose |
| KR102469464B1 (en) * | 2016-10-07 | 2022-11-22 | 신에쓰 가가꾸 고교 가부시끼가이샤 | Low-substituted hydroxypropyl cellulose, production method thereof, and solid preparation |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61100519A (en) * | 1984-10-23 | 1986-05-19 | Shin Etsu Chem Co Ltd | Hard capsule for drug |
| JP2602535B2 (en) * | 1988-09-02 | 1997-04-23 | ダイセル化学工業株式会社 | Aminoethylated water-soluble polymer and its production method |
| JP3059004B2 (en) * | 1992-09-18 | 2000-07-04 | ダイセル化学工業株式会社 | Low-substituted hydroxypropylcellulose having high solubility in aqueous alkali solution and method for producing the same |
| DE19504832A1 (en) * | 1995-02-14 | 1996-08-22 | Basf Ag | Solid drug preparations |
| JP3947244B2 (en) * | 1996-04-04 | 2007-07-18 | 日清ファルマ株式会社 | Preparation for peptic ulcer treatment |
| JP3718341B2 (en) * | 1998-05-12 | 2005-11-24 | 信越化学工業株式会社 | Low substituted hydroxypropylcellulose and process for producing the same |
-
1999
- 1999-01-18 JP JP00863699A patent/JP3572213B2/en not_active Expired - Lifetime
-
2000
- 2000-01-17 TW TW089100652A patent/TWI224111B/en not_active IP Right Cessation
- 2000-01-17 CN CN00100989A patent/CN1123576C/en not_active Expired - Lifetime
- 2000-01-17 KR KR10-2000-0001937A patent/KR100464749B1/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| JP3572213B2 (en) | 2004-09-29 |
| KR100464749B1 (en) | 2005-01-07 |
| JP2000204195A (en) | 2000-07-25 |
| CN1261603A (en) | 2000-08-02 |
| KR20000062477A (en) | 2000-10-25 |
| TWI224111B (en) | 2004-11-21 |
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