CN100487546C - White particle for display medium and information display utilizing the same - Google Patents
White particle for display medium and information display utilizing the same Download PDFInfo
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- CN100487546C CN100487546C CNB2005800064445A CN200580006444A CN100487546C CN 100487546 C CN100487546 C CN 100487546C CN B2005800064445 A CNB2005800064445 A CN B2005800064445A CN 200580006444 A CN200580006444 A CN 200580006444A CN 100487546 C CN100487546 C CN 100487546C
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Abstract
White particles for use in an information display having a particle assemblage containing at least white particles or powder fluid (3W) containing at least white particles as a particulate material sealed between two opposed substrates (1,2) at least one of which is transparent, the particle assemblage or powder fluid moved upon application of an electric field thereto to thereby display images, which white particles are composed of a resin from methylpentene or cycloolefin and titanium oxide. In preferred form, the white reflectance thereof is 40% or higher, and the white particles have such a heat resistance that when the white particles are spread on a glass substrate heated to 120 DEG C and allowed to stand still for 30 min while maintaining the heating of the glass substrate, no fusion bonding to the glass substrate occurs. As a result, there are provided white particles for display medium that exhibit high white reflectance, realizing high contrast in displayed images and that have satisfactory heat resistance.
Description
Technical field
The present invention relates to be used for the white particle of information display device; the fluid powder (liquidpowders) that wherein will comprise the particle of this white particle at least or comprise this white particle at least is sealed between two substrates; at least one substrate is transparent, wherein makes it is applied with the particle of electrostatic field or fluid powder moves with display message image for example.
Background technology
As the information display device of alternative LCD (LCD), proposed to utilize for example information display device of electrophoresis, electric chromium method, hot method (thermal method), two coloured particles rotary process of technology.
About these information display devices, owing to have the wide visual field of approaching conventional printed matter, have the advantage that less LCD consumed or had memory function, can be seen as cheap visual display unit of future generation, and expect that it extends to the demonstration that is used for portable device and electronic paper file.In recent years, proposed to be arranged in the electrophoresis between the substrate of facing, and it is expected equally by discrete particles and the colour developing microcapsule dispersion made of liquid and with this liquid.
Yet, such problem is arranged in electrophoresis: for because particle in electrophoresis liquid migration and the reason of toughness resistance, sensitivity slows down.In addition, such problem is arranged: because have that hyperbaric titan oxide particles is scattered in low-gravity solution, it precipitates, is difficult to keep the stability of disperse state easily, therefore lack imaging and reproduce stability.Even in the situation of microencapsulation, the degree that unit size is decreased to microcapsules overcomes substantive issue so that it is difficult to occur yet show no sign of.
Except the electrophoresis that utilizes the performance in solution, also proposed in recent years wherein under the condition of not using solution conductive particle and electric charge migrating layer are arranged on a kind of method in the part substrate.[the Transaction Pages 249-252 of Japanese imaging association " Japan Hardcopy ' 99 " (21-23 day in July, 1999)].Yet it is complicated that structure becomes, because will arrange electric charge migrating layer and other charge generation layer.In addition, be difficult to from conductive particle, disperse constantly electric charge, therefore the defective of deficient in stability is arranged.
As the method that overcomes above-mentioned variety of issue; the information display device that comprises message panel is known; wherein form cell in mode independent of each other by the partition wall between front substrate and the back substrate and with particle or fluid powder-tight in cell, and wherein make and it is applied with the particle of electrostatic field or fluid powder moves with display message image for example by means of Coulomb force etc.
In above-mentioned information display device, use the particle that comprises white particle and black particle or have the coloured particle of other colors usually.By resin, pigment fusion and mixing are pulverized and these particles are made mean grain size with the potpourri that obtains potpourri and will obtain thus for example is the pulverized particles of 9 μ m.In this case, if the white reflectivity of white particle is inadequately high by for example 40% or bigger, then have to make the defective of the contrast that can not obtain display image.In addition, when with granule sealed between substrate the time, the thermmohardening temperature that is not higher than bonding agent as the thermotolerance of fruit granule for example is higher than 120 ℃, then makes particle fusion and be bonded in defective on the substrate in addition.As this area is very known, in using PP (acrylic resin) or the particle of PBT (polybutylene terephthalate resin), be difficult to have contrast and stable on heating performance as resin.
Summary of the invention
The objective of the invention is to eliminate above-mentioned defective and the stable on heating white particle that has good white reflectivity and therefore have high display image contrast and have abundance is provided.
According to the present invention; be used for the white particle that the display medium of information display device is used; the fluid powder-tight that wherein will comprise the particle of this white particle at least or comprise this white particle at least is between two substrates; at least one substrate is transparent; and wherein make its particle or fluid powder that is applied with electrostatic field is moved with display image, it is characterized in that: improve the resin and the titanium dioxide that make by methylpentene or cycloolefin and form.
In addition, in the preferred embodiment that is used for the white particle of display medium according to the present invention, the white reflectivity is not less than 40%, and this improvement has such thermotolerance: make white particle is injected on 120 ℃ of following heated glass substrates and the heated condition of heated glass substrate do not detect bond vitrified after keeping 30 minutes.
According to the present invention, information display device is characterised in that and uses the above-mentioned white particle that is used for display medium.
Description of drawings
[Fig. 1] Fig. 1 a and 1b are the synoptic diagram of representing respectively to be used to use according to an embodiment of the driving method of the message panel of the information display device of white particle of the present invention.
[Fig. 2] Fig. 2 a and 2b are the synoptic diagram of representing respectively to be used to use according to another embodiment of the driving method of the message panel of the information display device of white particle of the present invention.
[Fig. 3] Fig. 3 a and 3b are the synoptic diagram of representing respectively to be used to use according to a kind of structure of the message panel of the information display device of white particle of the present invention.
[Fig. 4] Fig. 4 is that expression is used for using the synoptic diagram according to an embodiment of the shape of the partition wall of the message panel of the information display device of white particle of the present invention.
[Fig. 5] Fig. 5 is that explanation is used to estimate the synoptic diagram by the measuring method of the fade performance of the surface potential of corona charging device charging.
Embodiment
At first elaboration is used to use the basic structure that comprises according to the message panel of the information display device of the particle of white particle of the present invention.Be used for message panel of the present invention, electrostatic field is being applied on the particle that is sealed between two relative substrates.Charged particle attracts by this way along the direction of the electrostatic field that applies by means of the Coulomb force: under low potential charged particle towards the high potential side draught draw and under high potential charged particle draw towards the low potential side draught, thus by because the conversion operations of electromotive force and the direction that therefore changes electrostatic field can make particle move back and forth.Therefore can demonstrate image.Therefore, must come the design information display board by this way: make display medium to move equably and in reciprocal operating period or during storing state, keep stability.Here, with particle or fluid powder as under the situation of display medium, about being applied to the power on the particle, have because Coulomb force and attractive force, one-tenth image force, intermolecular force, liquid adhesion and gravity between particle with respect to battery lead plate.
Set forth example with reference to Fig. 1 a and 1b-Fig. 3 a and 3b according to message panel of the present invention.
In the example that is shown in Fig. 1 a and 1b, have different colors and move with vertical direction according to the electric field that applies in the outside of substrate 1 and 2, make by watching black particle 3B to demonstrate black for the observer or making by watch white particle 3W to demonstrate white for the observer with respect to substrate 1 and 2 by two or more sets display mediums 3 at least that one or more groups particle (showing white particle 3W that is made by these particles and the black particle 3B that is made by these particles here) is at least formed.The example in being shown in Fig. 1 a, in the example that is shown in Fig. 1 b,, for example latticed partition wall 4 forms cell by being arranged between substrate 1 and 2.In addition, in Fig. 1 b, omitted the partition wall that is arranged in nearside.
In the example that is shown in Fig. 2 a and 2b; At least two or more sets display mediums 3 that have different colors and be comprised of one or more groups particle (showing the white particle 3W that is made by these particles and the black particle 3B that is made by these particles here) at least are according to moving with the vertical direction with respect to substrate 1 and 2 by voltage being applied to the electric field that produces between the electrode 5 that is arranged in substrate 1 and the electrode 6 that is arranged in substrate 2, so that by watching black particle 3B to demonstrate black for the observer or so that by watch white particle 3W to demonstrate white for the observer. The example in being shown in Fig. 2 a, in the example that is shown in Fig. 2 b, for example latticed partition wall 4 forms cell by being arranged between substrate 1 and 2.In addition, in Fig. 2 b, omitted the partition wall that is arranged in nearside.
In the example that is shown in Fig. 3 a and 3b, at least one group of display medium 3 that has color and be made up of one or more groups particle (the white particle 3W that is made by these particles here) at least makes by watch white particle 3W to demonstrate white or the feasible color that demonstrates electrode 6 or substrate 1 by the color of watching electrode 6 or substrate 1 for the observer for the observer according to moving with the parallel direction with respect to substrate 1 and 2 by voltage being applied to the electric field that is produced between the electrode 5 that is arranged in substrate 1 and the electrode 6 that is arranged in substrate 1.The example in being shown in Fig. 3 a, in the example that is shown in Fig. 3 b,, for example latticed partition wall 4 forms cell by being arranged between substrate 1 and 2.In addition, in Fig. 3 b, omitted the partition wall that is arranged in nearside.
More than set forth and can be used for the situation that situation that white particle 3W replaced by the white fluid powder or black particle 3B are replaced by the black fluid powder.
The white particle that is used for display medium according to the present invention is characterised in that: because this white particle is made up of resin and titanium dioxide that methylpentene or cycloolefin make, therefore can consider also except low refractive index, low specific inductive capacity that thermotolerance (dimension Ka Shi softening temperature, fusing point) selects resin, and can obtain having the high white reflectivity and the white particle that is used for display medium of excellent heat resistance thus.Hereinafter, at first will set forth the structure of using according to the image display device of white particle of the present invention, and reference experiment will be elaborated above-mentioned feature.
Hereinafter, use each element according to the information display device of white particle of the present invention will be elaborated.
As substrate, at least one substrate is the transparent front substrate 2 that can see grain color by it from the outside of device, and preferred the use has the high coefficient of transmission for visible light and the material of excellent heat resistance.Back substrate 1 can be transparent or can be opaque.The example of baseplate material comprises: polymeric sheet material is polyethylene terephthalate, polyethersulfone, tygon, polycarbonate, polyimide or acrylic compounds (acryl) and have flexible metal sheet stock and roughly do not have flexible inorganic sheet stock for example glass, quartz for example.The thickness of substrate is preferably 2 to 5000 μ m, more preferably 5 to 2000 μ m.When thickness is too thin, become be difficult to keep intensity and between substrate apart from homogeneity, when thickness is thicker than 5000 μ m, defectiveness on thin display board.
In with the situation of arrangement of electrodes on message panel, what use as the material of electrode is for example aluminium, silver, nickel, copper, gold of metal, perhaps for example ITO, indium oxide, conductive tin oxide, electroconductive zinc oxide etc. of conductive metal oxide, perhaps for example polyaniline, polythiophene etc. of electric conductive polymer, and by selecting to use them aptly.As the electrode moulding method, use wherein by means of sputtering method, vaccum gas phase sedimentation method, CVD (chemical vapor deposition) method, cladding process etc. above-mentioned material is made the method for film, perhaps wherein with conductive material with solvent mixes with synthetic resin adhesive and with the method for potpourri injection.For be arranged in observation side (display surface side) substrate on electrode for the transparency be necessary, but for the substrate at the back side not necessarily.In both cases, can use transparent aptly and above-mentioned material that have pattern formation ability.In addition, unless do not have electric conductivity or have any obstruction in optical transparence, the thickness of electrode can be suitable so, and it is preferably 3 to 1000nm, and more preferably 5 to 400nm.The material that is arranged in the electrode on the back substrate and thickness are identical with those of electrode on being arranged in the substrate that shows side, but the transparency not necessarily.In this case, can be with external voltage and direct current or the alternating current stack that applies.
As the partition wall of arranging as required 4, the shape of partition wall designs according to the type of the display medium that is used to show and without limits aptly.Yet, preferably the width of partition wall is arranged to 2 to 100 μ m, more preferably 3 to 50 μ m, and the height of partition wall is arranged to 10 to 500 μ m, more preferably 10 to 200 μ m.See from the plane of substrate as shown in Figure 4 like that, the formed cell of making by each free rib of partition wall has square, triangle, linear, annular and sexangle, and the arrangement with for example latticed, cellular and mesh-like.Preferably, corresponding to being made as far as possible little from the part (zone of the frame part of display element) that shows the partition wall xsect that side is seen.In this case, can improve the sharpness that image shows.Yet the forming method of partition wall is not particularly limited, and silk screen print method, sand-blast, photoetching process and additive process (additive method) are arranged.In the middle of them, the preferred photoetching process of using resin film that adopts.
To set forth according to white particle of the present invention then.White particle according to the present invention is made up of following material: resin that is made by methylpentene or cycloolefin and titanium dioxide be as principal ingredient, and can be as comprising charge control agent, inorganic additive etc. with known as required identical.
The example of charge control agent comprises, but be not defined in especially, negative charge controlling agent is oil-soluble dyes, fourth stage ammonium salt based compound, calixarene compound, boron-containing compound (benzoic acid boron complexes) and the nitro imidazole derivatives of salicylic acid metal complex, metallic azo dyes, containing metal (metal ion or metallic atom) for example.The example of positive charge control agent comprises: aniline black byestuffs, triphenyl methane compound, fourth stage ammonium salt compound, polyamino resin, imdazole derivatives etc.In addition, can be with metal oxide for example micro silica particle, ultrafine titanium oxide particle, ultra-fine alumina particle etc.; Nitrogenous annular compound is pyridine etc. and these derivant or salt for example; Be used as charge control agent with the resin that contains multiple organic pigment, fluorine, chlorine, nitrogen etc.
Although the manufacture method of particle is not particularly limited, can adopt the mixing/breaking method of the toner that for example is used to prepare electrofax similarly.In addition, also can adopt the method that resin or charge control agent etc. is coated in the surface of for example inorganic or organic pigment of powder.
In addition, the mean grain size d (0.5) as the particle that uses preferably is set to d (0.5) 0.1-50 μ m and preferably uses homogeneous granules.If mean grain size d (0.5) exceeds this scope, image definition deterioration sometimes then, if mean grain size less than this scope, then the cohesive force between the particle becomes bigger and has stoped moving of particle.
In addition, preferably the particle grain size distribution span by the following formula definition is no more than 5, preferably is no more than 3:
Span=(d (0.9)-d (0.1))/d (0.5);
(here, d (0.5) is meant the particle size values of being represented by μ m, wherein having the amount that particle diameter is greater than or less than the particle of this value is 50%, d (0.1) is meant the particle size values of being represented by μ m, wherein, having particle diameter is 10% less than the amount of the particle of this value, and d (0.9) is meant the particle size values of being represented by μ m, and wherein having particle diameter is 90% less than the amount of the particle of this value).
If the particle grain size distribution span is arranged to be no more than 5, then particle diameter becomes evenly and can carry out homogeneous granules and move.
In addition, as the correlativity between the particle, the d (0.5) that preferably will have the particle of minimum diameter is arranged to be no more than 50 with respect to the ratio of the d (0.5) of the particle with maximum gauge, preferably is no more than 10.
Here, can measure above-mentioned size distribution and particle diameter by means of laser diffraction/scattering method.When laser radiation is on the particle that will measure, because the light intensity distributions pattern appears in diffraction/scattered light and space ground.This light intensity distributions pattern is corresponding to particle diameter, and therefore can measure particle diameter and size distribution.
In the present invention, defined to distribute and obtained particle diameter and size distribution by dimension criteria.Especially, can be by means of wherein placing the measurement mechanism Mastersizer 2000 (Malvern Instruments Ltd.) of the particle of nitrogen stream to measure particle diameter and size distribution by the analysis software of installing (it distributes based on the dimension criteria owing to Mie ' s theory) calculating.
Here, repeat persistence in order further to improve, the insoluble rate with solvent of water-intake rate of the resin of particle is formed in control effectively.
The water-intake rate of preferably forming the resin of particle is no more than 3wt%, especially is no more than 2wt%.In this case, according to ASTM-D570 carry out the measurement of water-intake rate and measuring condition be 23 ℃ following 24 hours.
About the insoluble rate of the solvent of particle, preferably the insoluble rate of solvent by the particle of following formula definition is not less than 50%, more preferably is not less than 70%:
The insoluble rate of solvent (%)=(B/A) * 100;
(here, A is the weight of resin Composition before being impregnated into solvent, and B is the weight of impregnated with particles being gone into the resin Composition after the fine solvent 24 hours under 25 ℃).
If less than 50%, then producing on the particulate material surface of composition particle when long-time the preservation, the insoluble rate of solvent oozes out.In this case, it has influenced with the adhesion of particle and has stoped moving of particle.Therefore, there is it to influence the such situation of persistence that image shows.
Here, as the solvent that is used to measure the insoluble rate of solvent (fine solvent), the preferred use: for fluoroplastic for for example methyl ethyl ketone etc., for polyamide for for example methyl alcohol etc., be for example methyl ethyl ketone, toluene etc. for the acrylic acid series carbamate resins, be for example acetone, isopropyl alcohol etc. for melamine resin, be for example toluene etc. for silicone resin.
White particle according to the present invention has chargeding performance.Owing to must make particle keep charged electric charge, so preferred volume resistivity is 1 * 10
10Ω cm or bigger particle more preferably have the particle by the performance of charge decay slowly of following measuring method evaluation.
That is, the particle that will be used for display medium is arranged in the distance from corona discharger 1mm, and the voltage of 8kV is applied on the corona discharger producing corona discharge, and this makes surface charging.The variation of surface measurements electromotive force is to determine suitability then.In this case, preferentially be chosen in 0.3 second after its maximum surface potential will be greater than the material of 300V, more preferably being chosen in its maximum surface potential after 0.3 second will be greater than the material of 400V as the material of forming particle.Can carry out above-mentioned measurement by this way: the particle that will be used for display medium by means of pressing, heating/fusion method, rolling process etc. is made has the film that thickness is 5-100 μ m, and to make the distance between film surface and the corona discharger be 1mm.
In addition, measure above-mentioned surface potential by means of as shown in Figure 5 the CRT2000 that produces by QEA Inc..In this device, with chuck 21 two end portions of roll shaft is fixed, and separate to form measuring unit with the scorotron discharger 22 and the surface potential meter 23 of predetermined interval with compactness.Preferred adopt such method to measure its surface potential: to make the measuring unit distance be used for the disposing of surperficial 1mm of the particle of display medium or film apart from subtend; and by making measuring unit move to other end part from an end parts of roll shaft with even velocity; be accompanied by roll shaft and keep halted state, provide surface charge simultaneously.In addition, measurement environment will be set to 25 ± 3 ℃ temperature and the humidity of 55 ± 5RH%.
The quantity of electric charge of display medium depends on measuring condition aptly.Yet, the quantity of electric charge that is understood that the display medium of the display medium that is used for message panel depends primarily on the initial charge amount, with respect to the contact of partition wall, with respect to the contact of substrate, because the charge decay of the time of passage, and the saturation value that is used for especially, the particle of display medium during the charging behavior is a principal element.
After inventor's various researchs, discovery can blow out the proper range of charge value that the quantity of electric charge that method (blow-off method) is used for the particle of display medium with measurement estimates to be used for the particle of display medium by using identical carrier granular.
The back will elaborate this measuring method.By blowing out method, the particle that can be used in display medium fully contacts with carrier granular and can measure the quantity of electric charge of each particle that is used for display medium of per unit weight by measuring its saturated quantity of electric charge.Then, can be by obtaining to be used for each particle grain size of display medium and the surface charge density that proportion calculates each particle that is used for display medium respectively.
In information display device, influence down to ignoring it because the particle diameter of the particle that is used for display medium (being called particle hereinafter) of composition display medium is little and influence gravity is too little, so proportion can not influence moving of particle.Yet, for the quantity of electric charge of particle, have the mean charge amount of identical particle diameter and identical per unit weight as fruit granule, to the situation of twice, the quantity of electric charge difference that is kept is to twice in the proportion difference of particle.Therefore, be understood that the preferred surface charge density (unit: μ C/m that passes through
2) estimate the charge characteristic of the particle that is used for information display device, the proportion of this and particle is irrelevant.
In message panel as two groups of particles of use of display medium, if the scope of surface charge density in the particle and the difference of surface charge density are remained in the suitable scope, then two groups of particles have enough quantities of electric charge by contacting with each other, and have kept locomotive function by electrostatic field.
Here, in order to make the charge characteristic abundance of two groups of particles of existence located adjacent one another in message panel, then must obtain to a certain degree surface charge density difference distinguishing the moving direction of these two kinds of particles, but always must not make the difference of surface charge density bigger.In the information display device that utilizes particle to move, when particle grain size is big, be used for determining that the principal element of the leaping of particle/mobile electrostatic field (voltage) is that electricity becomes image force.Therefore, for particle being moved, then preferably make the quantity of electric charge low by low electrostatic field (voltage).In addition, when particle grain size hour, be used to determine leap/principal element of mobile electrostatic field (voltage) is a non-electricity, for example intermolecular force, liquid adhesion etc.Therefore, for particle being moved, then preferably make quantity of electric charge height by low electrostatic field (voltage).Yet,, can not only stipulate by the particle diameter and the quantity of electric charge because these phenomenons depend primarily on the surface nature (material, shape) of particle.
The inventor finds; have in the message panel of mean grain size as the particle of 0.1-50 μ m using, the absolute value of the difference between the surface charge density of two groups of particles being measured by the method that blows out of the particle that uses same type or two groups of fluid powder is 10-150 μ C/m
2The time, the absolute value of the difference between surface charge density is 20-150 μ C/m
2Situation under, can obtain can be used for the particle of information display device.
To set forth the fluid powder that comprises at least according to white particle of the present invention then.
In the present invention, term " fluid powder " is meant the intermediate materials that has liquid properties and particle performance and show self flowability under the condition of not using gases power and hydraulic power.Preferably, it is to have excellent fluidity so that there is not the material at the angle of repose (repose angle) that defines powder flowbility.For example, liquid crystal be defined as between liquid and the solid in the middle of mutually, and have flowability that shows characteristics of liquids and anisotropy (optical property) (the Heibonsha Ltd.: encyclopedia) that shows solid property.On the other hand, little and be subjected to the attraction of gravity if it is the ground that goes to zero, then the definition of particle is material (Maruzen Co., the Ltd.: the physics subject books) with limited quality.Here, even for example gas-solid fluidised body of special state and liquid-solid fluidised body are also arranged in particle.If gas flows on the particle from base plate, then the force-responsive on top works to particle in gas velocity.In this case, when the power on top and gravitational equilibrium, gas-solid fluidised body is meant the state of easy fluidisation.In an identical manner, liquid-solid fluidised body is meant by the state of liquid fluidisation (Heibonsha Ltd.: encyclopedia).In the present invention, discovery can make the intermediate materials that has liquid properties and particle performance and show self flowability under the condition of not using gases power and hydraulic power especially, and it is defined as the fluid powder.
Promptly, as identical with the definition of liquid crystal (the middle phase between liquid and the solid), fluid powder according to the present invention is the material that shows the intermediateness with liquid properties and particle performance, its extremely be difficult to be subjected to show above-mentioned particle performance gravity influence and show high flowability.This class material can aerosol state, promptly obtain as the dispersed system that dispersion floats in the gas in metastable mode with wherein solid shape or liquid material, therefore in information display device according to the present invention with solid material as dispersion.
For the message panel of target of the present invention has such structure: make by as dispersion stable float on the fluid powder that the solid material that shows high fluidity in the gas and in aerosol state forms and be sealed between two opposing substrates, wherein one of these two substrates are transparent.Can be by means of such fluid powder easily and stably being moved by applying Coulomb force that low-voltage produces etc.
As mentioned above, the fluid powder is meant the intermediate materials that has liquid properties and particle performance and show self flowability under the condition of not using gases power and hydraulic power.This class fluid powder becomes aerosol state especially.In information display device according to the present invention, the fluid powder is so that solid material uses as the state that dispersion relatively and stably floats in the gas.
As aerosol state, the apparent volume in the preferably maximum floating state is a twice in the non-floating state or bigger, and 2.5 times in the non-floating state or bigger more preferably most preferably are in the non-floating state 3 times or bigger.In this case, the upper limit without limits, but preferably apparent volume is in the non-floating state 12 times or littler.
If the apparent volume in the maximum floating state, shows then that control becomes difficult less than twice.On the other hand, if the apparent volume in the maximum floating state greater than 12 times, then during fluid powder packing operation access to plant, the not convenient for example particle of manipulation excessively divides breaking up to occur.That is, this measures in the following manner: the fluid powder is packed into see the transparent closed container of fluid powder by it; With container itself vibration or fall to obtain maximum floating state; And measure apparent volume from the outside of container at this moment.Especially, 1/5 the fluid powder that will have volume and be a container as the fluid powder pack into have diameter (internal diameter) for 6cm, highly be the container that has polypropylene cap of 10cm (name of product: by As-oneCo., Ltd. the I-boy of Sheng Chaning), this container is put into Vib. and make wherein with 3 times back and forth/second the speed vibration that repeats the distance of 6cm carried out 3 hours.Then, obtain apparent volume in the maximum floating state by the apparent volume after vibration stops just.
In addition, according to the present invention, preferably following formula is satisfied in the variation of the time of the apparent volume of fluid powder:
V
10/V
5>0.8；
Here, V
5Be illustrated in the apparent volume (cm of the fluid powder after maximum floating state 5 minutes
3); V
10Be illustrated in the apparent volume (cm of the fluid powder after maximum floating state 10 minutes
3).In this case, in message panel according to the present invention, preferably the time with the apparent volume of fluid powder changes V
10/ V
5Be set to greater than 0.85, more preferably greater than 0.9, most preferably greater than 0.95.If should the time change V
10/ V
5Be not more than 0.8, then the fluid powder is equal to conventional particle substantially, and therefore can not keep high-speed response and persistence according to the present invention.
In addition, the mean grain size d (0.5) that preferably forms fluid particles of powder material is 0.1-20 μ m, and more preferably 0.5-15 μ m most preferably is 0.9-8 μ m.If mean grain size d (0.5), shows then that control becomes difficult less than 0.1 μ m.On the other hand, if mean grain size d (0.5) greater than 20 μ m, then show be possible but opaque powder reduce and therefore the device of thin shape be difficult to solve.Here, the mean grain size d (0.5) of composition fluid particles of powder material is equal to the d (0.5) in the following size distribution span.
Preferably, the size distribution span of forming fluid particles of powder material that is defined by following formula is no more than 5, preferably is no more than 3:
Size distribution: span=(d (0.9)-d (0.1))/d (0.5);
Here, d (0.5) is meant the particle size values of being represented by μ m, wherein having particle diameter is 50% greater than the amount of the composition fluid particles of powder material of this value, d (0.1) is meant the particle size values of being represented by μ m, wherein having particle diameter is 10% less than the amount of the composition fluid particles of powder material of this value, d (0.9) is meant the particle size values of being represented by μ m, and wherein having particle diameter is 90% less than the amount of the composition fluid particles of powder material of this value.Be arranged to be no more than 5 if will form the size distribution span of fluid particles of powder material, then particle diameter becomes evenly and can carry out uniform fluid powder and move.
Here, can measure above-mentioned size distribution and particle diameter by means of laser diffraction/scattering method.When laser radiation was on the particle that will measure, therefore the light intensity distributions pattern appearred to the space owing to diffraction/scattered light.This light intensity distributions pattern is corresponding to particle diameter, and therefore can measure particle diameter and size distribution.In the present invention, defined to distribute and obtained particle diameter and size distribution by dimension criteria.Especially, can be by means of wherein placing the measurement mechanism Mastersizer 2000 (MalvernInstruments Ltd.) of the particle of nitrogen stream to measure particle diameter and size distribution by the analysis software of installing (it distributes based on the dimension criteria owing to Mie ' s theory) calculating.
Can be by the resin of necessity, charge control agent, colorant, adjuvant etc. being mixed and they are pulverized, or by by monomer polymerization, perhaps by with resin, charge control agent, colorant and adjuvant etc. particle coated being formed the fluid powder.To set forth the exemplary of the resin of forming the fluid powder, charge control agent, colorant, adjuvant etc. hereinafter.
The exemplary of resin comprises: carbamate resins, acrylic resin, vibrin, acrylic carbamate resins, silicone resin, nylon resin, epoxy resin, styrene resin, butyral resin, vinylidene resin, melamine resin, phenolics, fluorocarbon polymer, and can be with two or more resin combination.For the purpose of control with the attractive force of substrate, preferred acrylic carbamate resins, acrylic carbamate silicone resin, acrylic carbamate fluorocarbon polymer, carbamate resins, fluorocarbon polymer.
The example of charge control agent comprises: positive charge control agent, comprise for example metallic azo dyes of fourth stage ammonium salt compound, aniline black byestuffs, triphenyl methane compound, imdazole derivatives etc. and negative charge controlling agent, salicylic acid metal complex, nitro imidazole derivatives etc.
About colorant, can use various organic or inorganic pigment or dyestuff.
The example of black pigment comprises: carbon black, cupric oxide, manganese dioxide, nigrosine and activated charcoal.
The example of blue pigment comprises: the C.I. pigment blue 15: 3, the phthalocyanine blue of C.I. pigment blue 15, Berlin blue, cobalt blue, alkali blue lake, Victoria blue color lake, phthalocyanine blue, metal-free phthalocyanine blue, part chlorination, elementary sky blue and indanthrene blue BC.
The example of red pigment comprises: red oxide, cadmium red, lead plaster, mercuric sulphide, cadmium, permanent red 4R, lithol red, pyrazolone red, watching red, calcium salt, C lake red CAN'T D, bright fuchsin 6B, eosine lake, rhodamine color lake B, alizarine lake, bright fuchsin 3B and C.I. paratonere 2.
The example of yellow uitramarine comprises: chrome yellow, zinc chromate, cadmium yellow, yellow iron oxide, inorganic elementary Huang (mine ralfirst yellow), nickel titanium yellow, navel orange Huang, naphthol yellow S, hansa yellow (hanzayellow) G, hansa yellow 10G, benzidine yellow G, benzidine yellow G R, quinoline yellow lake, permanent yellow NCG, tartrazine lake and C.I. pigment Yellow 12.
The example of viridine green comprises: chrome green, chromium oxide, pigment green B, C.I. pigment Green 7, malachite green color lake and ultimate yellowish green G (final yellow green G).
The example of orange pigment comprises: chrome red Huang, molybdate orange, permanent orange GTR, pyrazolone orange, Balkan orange, indanthrene brilliant orange RK, Benzidine orange G, the bright orange GK of pyrazolone and C.I. pigment orange 31.
The example of violet pigment comprises: manganese violet, elementary purple B and methyl violet color lake.
The example of Chinese white comprises: zinc white, titanium dioxide, stibium trioxide and zinc sulphide.
The example of replenishers comprises: baryta powder, barium carbonate, clay, silica, white carbon, talcum and alumina white.Nigrosine, methylene blue, rose-red, quinoline yellow and ultra marine blue are arranged in addition as various dyestuffs, for example basic-dyeable fibre, acid dyes, disperse dyes, direct dyes etc.
The example of inorganic additive comprises: titanium dioxide, zinc white, zinc sulphide, antimony oxide, lime carbonate, pearl white, talcum, silica, calcium silicate, alumina white, cadmium yellow, cadmium red, titan yellow, Prussian blue, Armenia is blue, cobalt blue, cobalt green, cobalt violet, iron oxide, carbon black, Mn ferrite is black, vectolite is black, copper powder, aluminium powder.
These colorants and inorganic additive can be separately or with its two or more be used in combination.Especially, carbon black is preferably black colorant, and titanium dioxide is preferably white color agents.
Yet,, can not obtain to show the fluid powder of aerosol state iff above material being mixed or contrivance of no use (contrivance) coating.It is unqualified that formation shows the conventional method of fluid powder of aerosol state, but preferably adopt following method.
At first, preferably will have mean grain size is 20-100nm, and the fine inorganic particles of preferred 20-80nm is fixed on the surface of the material of forming the fluid powder.In addition, preferably these fine inorganic particles are made by two or more sets fine graineds.Further preferably handle fine inorganic particles by silicone oil.Here, about fine inorganic particles, can use silicon dioxide (silica), zinc paste, aluminium oxide, magnesium oxide, cerium oxide, iron oxide, cupric oxide etc.In this case, the fine grain method of fixed inorganic is important.For example, can use the hybridization machine (NARA Machinery Industry Co., Ltd.) or mechanical fusion (Hosokawa Micron Co. Ltd.) and in predetermined condition (for example process time) forms down the fluid powder that shows aerosol state.
In addition, the gas of control loop in the gap of particle between the substrate and fluid powder importantly in the present invention, and the control of suitable gas helps to improve exhibit stabilization.Especially, importantly the humidity of gap gas is controlled under 25 ℃ and be no more than 60%RH, preferably be no more than 50%RH, more preferably no more than 35%RH.
Above the gap be meant: for example among Fig. 1 a and 1b-Fig. 3 a and the 3b like that, the gas part around powder (or fluid powder) of the sealing branch acquisition that occupies part (under the situation of arranging partition wall) and install that occupies part, partition wall 4 by will from the space between substrate 1 and the substrate 2, getting rid of electrode 5,6, particle 3 (or fluid powder).
If it has above-mentioned humidity, then the type of gap gas but is preferably used dry air, drying nitrogen, dry helium gas, dry carbon dioxide, dry methane gas etc. without limits.Must with this air seal in device to keep above-mentioned humidity.For example, importantly carry out loaded particles or fluid powder under the atmosphere of predetermined moisture and with the operation of substrate assembling having, and use seal element and encapsulating method to be mingled with the humidity of the outside of holdout device.
In message panel according to the present invention, can move and can keep contrast as fruit granule or fluid powder, then the interval between the substrate and is adjusted to it 10-500 μ m without limits usually, is preferably 10-200 μ m.
In addition, preferably the volume occupation rate in the interval between opposing substrates controls to 5-70 volume %, more preferably 5-60 volume % with particle or fluid powder.Volume occupation rate as fruit granule or fluid powder surpasses 70 volume %, and then particle or fluid powder become and be difficult to move, if it, then can not obtain sufficient contrast less than 5 volume % and can not carry out distinct image to show.
Hereinafter, will further set forth the present invention according to embodiment and comparative example especially.Yet the present invention is not limited to following experiment.
At first preparation is shown in the various resin materials and the various pigment that are shown in the following table 2 in the following table 1.
[table 1]
| Material | ProductName | Production number | Fusing point | Specific inductive capacity | The producer |
| PBT | DURANEX | 300FT | (225)MP | 3.3 | WinTech?Polymer?Ltd. |
| PP | NOVATEC | MA03 | 153 | 2.3 | Japan?Polychem?Cooperation |
| Methylpentene polymer | TPX | RT-18 | 173 | 2.12 | Mitsui?Chemicals，Inc. |
| Cycloolefin | ZEONOR | 1410R | 135 | 2.3 | ZEON?CORPORATION |
| Amorphous polyester | Eastalloy | DA003 | 118 | 2.4 | EASTMAN?Chemical?Japan co.，ltd. |
[table 2]
| Material | ProductName | Production number | Particle diameter (μ m) | Oil absorption | Surface treatment | The producer |
| Titanium dioxide | TIPAQ UE | CR-90 | 0.25 | 21 | Al、Si | ISHIHARA?SANGYO KAISHA，LTD. |
| Titanium dioxide | TIPAQ UE | CR60-2 | 0.21 | 14 | Al, organic material | ISHIHARA?SANGYO KAISHA，LTD. |
| Titanium dioxide | TIPAQ UE | CR63 | 0.21 | 14 | Al, Si, organic material | ISHIHARA?SANGYO KAISHA，LTD. |
As described below then, to the resin material and the pigment of preparation thus mix, the operation of kneading and granulation.At first by means of adopting freezing crusher: TAP-ULF-1C type (Tokyo Atomizer Co., Ltd.) freezing breaking method will be pulverized by the resin beads that the various resin materials shown in the table 1 are made, and obtain having the crushing resin that particle diameter is 200-300 μ m.(MITSUI MINING CO., LTD) crushing resin that will obtain thus and pigment mix by means of Henschel (HENS CHEL) mixer: FM50-1 then.Behind married operation, had the embodiment 1-5 of the composition in following table of being shown in 3 and the potpourri of comparative example 1-3 separately.Mediate to form bead by the potpourri that uses double screw extrusion machine: KZW15-45MG (TECHNOVEL CORPORATION) to obtain thus then.In this case, the cylinder temperature of double screw extrusion machine is 200-250 ℃, and the screw rod revolution is 150rpm.
[table 3]
Then, as described below the bead that obtains is thus carried out crushing operation.At first as identical with above method, obtaining bead, and the freezing pulverizing of the bead that will obtain thus is to obtain the having coarse particle that particle diameter is 200-400 μ m with resin material and pigment mixing, kneading and granulation.Then by means of aeropulverizer: (Nippon Pneumatic Mfg.Co., Ltd.) coarse particle that will obtain thus is in small, broken bits, to obtain having the fine grained of about 9 mu m ranges of particle diameter for LAB JET MILLLJ/MDS2.The fine grained classification that will obtain thus then is to obtain the particle that average medium particle diameter is 9 μ m.
Measure the resin property of forming according to the particle of thus obtained embodiment 1-5 and comparative example 1-3 (specific inductive capacity, transparency) then.The result is summarized in the following table 4.Here, specific inductive capacity and transparency are from volume class (catalogue) acquisition of product separately.Measure PVC by calculating based on the volume content of pigment.Measure white reflectivity in the following manner: according to the free-falling method with particle jetting on the surface of ito glass substrate; Measure every layer white reflectivity; Draw white reflectivity according to the number of layer; And thickness measure white reflectivity at 10 μ m.Measure thermotolerance in the following manner: particle jetting is being heated to by electric furnace on 120 ℃ the glass substrate of surface temperature; And after the heated condition of glass substrate being kept 30 minutes, determined whether to occur the bond vitrified of particle with respect to glass substrate by electric furnace.In this was measured, symbol zero was illustrated in and does not occur the state of particle with respect to the glass substrate bond vitrified under 120 ℃, and the state of particle with respect to the glass substrate bond vitrified appears in symbol * be illustrated under 120 ℃.
[table 4]
| | Embodiment | 1 | |
|
|
|
Comparative example 1 | Comparative example 2 | Comparative example 3 | |
| ProductName | Production number | |||||||||
| Methylpentene | RT18 | 100 | 100 | |||||||
| Cycloolefin | 1410R | 100 | 100 | 100 | ||||||
| PP | MA03 | 100 | ||||||||
| PBT | 300FT | 100 | ||||||||
| Amorphous polyester | 100 | |||||||||
| Titanium dioxide | CR90 | 100 | 100 | |||||||
| CR60-2 | 100 | 218 | 179 | |||||||
| Resin property | ||||||||||
| Specific inductive capacity | 1MHz | 2.12 | 2.3 | 2.3 | 2.12 | 2.3 | 2.3 | 3.3 | 2.4 | |
| Transparency | ％ | 94 | 91 | 91 | 94 | 91 | - | - | 81 | |
| The potpourri performance | ||||||||||
| PVC | ％ | 17 | 20 | 20 | 30 | 30 | 18 | 24 | 23 | |
| Particle diameter | μm | 9.172 | 10.592 | 10.756 | 9.233 | 10.31 | 11.336 | 10.202 | 8.89 | |
| The white reflectivity | ％ | 43 | 40 | 44 | 50 | 51 | 38 | 37 | 41 | |
| Thermotolerance | ○ | ○ | ○ | ○ | ○ | ○ | ○ | × |
From the result who is shown in Table 4, be understood that with comparative example 1-3, wherein they are compared with the white particle that titanium dioxide is formed by PP, PBT or amorphous polyester, according to embodiments of the invention 1-5, wherein their white particles of being made up of methylpentene or cycloolefin and titanium dioxide have high white reflectivity (surpassing 40%) and thermotolerance.In addition, be understood that if can realize that low specific inductive capacity and high transparency as resin property, then can improve white reflectivity.In addition, be understood that if increase PVC, then white reflectivity becomes higher.In these cases, generally speaking, because PVC becomes excessive higher, then therefore the processibility deterioration extraordinarily that becomes has been understood that only PVC scope.In addition, if the type of titanium dioxide changes (particle diameter and surface treatment differ from one another), then white reflectivity is different and be understood that the titanium dioxide of most appropriate type.
Industrial applicibility
White particle for display medium according to the present invention can be preferred for such application: so that improve by making particle or fluid powder moving carry out the image display device contrast that image shows therein, and use the image display device of above-mentioned white particle to can be used for the image-displaying member of the usefulness such as mobile device such as notebook personal computer, PDAs, portable phone; The electronic paper that is used for the usefulness such as e-book, electronic newspaper; Be used for billboard such as signboard, poster, blackboard etc.; The image-displaying member that is used for the usefulness such as electronic calculator, domestic electronic application product, automatic articles for use; The card display element that is used for the usefulness such as contact card, IC-card; With the display element that is used for the usefulness such as electronics POP, e-advertising, electronic price label, electronic music, RF-ID equipment.
Claims (4)
1. be used for the white particle that the display medium of information display device is used; the fluid powder-tight that wherein will comprise the particle of this white particle at least or comprise this white particle at least is between two substrates; at least one substrate is transparent; and wherein make its particle or fluid powder that is applied with electrostatic field is moved with display image, it is characterized in that this white particle comprises resin and the titanium dioxide that is made by methylpentene or cycloolefin.
2. the white particle that display medium according to claim 1 is used, wherein, white reflectivity is not less than 40%.
3. the white particle that display medium according to claim 1 and 2 is used, wherein this improvement has such thermotolerance: make white particle is sprayed be on 120 ℃ of following heated glass substrates and the heated condition of heated glass substrate kept 30 minutes after do not detect bond vitrified.
4. an information display device is characterized in that using the wherein white particle that described display medium is used according to claim 1-3.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP017869/2004 | 2004-01-27 | ||
| JP2004017869 | 2004-01-27 | ||
| JP073890/2004 | 2004-03-16 |
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| CN1926464A CN1926464A (en) | 2007-03-07 |
| CN100487546C true CN100487546C (en) | 2009-05-13 |
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Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6177368B1 (en) * | 1998-03-16 | 2001-01-23 | Russell J. Fisher | Blast resistant laminate composite container wall construction |
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6177368B1 (en) * | 1998-03-16 | 2001-01-23 | Russell J. Fisher | Blast resistant laminate composite container wall construction |
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