CA1131489A - Toner powder containing an epoxy resin modified by chemical reaction and by intermolecular linking and/or epoxy hardening - Google Patents
Toner powder containing an epoxy resin modified by chemical reaction and by intermolecular linking and/or epoxy hardeningInfo
- Publication number
- CA1131489A CA1131489A CA333,512A CA333512A CA1131489A CA 1131489 A CA1131489 A CA 1131489A CA 333512 A CA333512 A CA 333512A CA 1131489 A CA1131489 A CA 1131489A
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- Prior art keywords
- epoxy
- epoxy resin
- approximately
- toner powder
- molar mass
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/087—Binders for toner particles
- G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- G03G9/08753—Epoxyresins
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- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Developing Agents For Electrophotography (AREA)
Abstract
ABSTRACT
A heat fixable toner powder for developing latent electrostatic images which powder comprises finely divided toner particles comprising color-ing constituents, a thermoplastic material, and, if desired a charge regulator said thermoplastic material substantially comprising epoxy resin whose original epoxy groups are blocked partly by chemical reaction with a monofunctional organic compound and partly by linking or bonding, characterised in that the epoxy resin has an epoxy molar mass between approximately 2,000 and at most 10,000 and comprises a first modified epoxy resin obtained by blocking the epoxy groups of at least one first epoxy resin starting material with a molar mass of a maximum of approximately 1,000 and with an epoxy molar mass of a maximum of approximately 700 in a proportion of approximately 25-95% by chemical reaction with a monofunctional carboxylic acid, phenol or diaryl sulphonamide and in a proportion of approximately 5-75% by linking and/or bonding by means of intermolecular reaction with the hydroxyl groups of said first epoxy resin starting material and/or by means of an epoxy hardener, or a mixture of at least 20 parts by weight of said first modified epoxy resin with a maximum of 80 parts by weight of a phenoxy resin and/or a second modified epoxy resin obtained by an at least 5% blocking of the epoxy groups of at least one second epoxy resin starting material with a molar mass of at least approximately 1,500 and an epoxy molar mass of at least approximately 900 by linking and/or bonding by means of intermolecular reaction or an epoxy hardener. The toner powder is particularly suitable for use in a high volume copying apparatus with a contact fixing device and can be excellently fixed at an extremely low temperature in a few hundredths of a second.
A heat fixable toner powder for developing latent electrostatic images which powder comprises finely divided toner particles comprising color-ing constituents, a thermoplastic material, and, if desired a charge regulator said thermoplastic material substantially comprising epoxy resin whose original epoxy groups are blocked partly by chemical reaction with a monofunctional organic compound and partly by linking or bonding, characterised in that the epoxy resin has an epoxy molar mass between approximately 2,000 and at most 10,000 and comprises a first modified epoxy resin obtained by blocking the epoxy groups of at least one first epoxy resin starting material with a molar mass of a maximum of approximately 1,000 and with an epoxy molar mass of a maximum of approximately 700 in a proportion of approximately 25-95% by chemical reaction with a monofunctional carboxylic acid, phenol or diaryl sulphonamide and in a proportion of approximately 5-75% by linking and/or bonding by means of intermolecular reaction with the hydroxyl groups of said first epoxy resin starting material and/or by means of an epoxy hardener, or a mixture of at least 20 parts by weight of said first modified epoxy resin with a maximum of 80 parts by weight of a phenoxy resin and/or a second modified epoxy resin obtained by an at least 5% blocking of the epoxy groups of at least one second epoxy resin starting material with a molar mass of at least approximately 1,500 and an epoxy molar mass of at least approximately 900 by linking and/or bonding by means of intermolecular reaction or an epoxy hardener. The toner powder is particularly suitable for use in a high volume copying apparatus with a contact fixing device and can be excellently fixed at an extremely low temperature in a few hundredths of a second.
Description
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The present inyention relates to a toner powder suitable for developing latent electrostatic images and which can be fixed by heat, essentially comprising finely divided coloured toner particles which include thermoplastic material, colouring constituents and if desired a charge regulator. The invention more particularly relates to a toner powder whose thermoplastic material mainly comprises epoxy resin, whose original epoxy groups have been blocked in a given manner and in a given percentage. The invention also relates to a process for the preparation of such a toner powder, a two-component developer containing such a toner powder and a single-component developer containing such a toner powder.
Toner powders are widely used in the form of so-called single and two-component developers for making visible latent electrostatic images of the type formed on a suitable surface in electrography or electrophoto-graphy.
Two-component developers have a toner powder whose toner particles contain an insulating thermoplastic material mixed with relatively large carrier particles. By contact with or friction against the carrier particles the toner particles receive an electrostatic charge and consequently adhere to the carrier particles. In general toner and carrier particles are matched to one another in such a way that the toner particles assume a charge having an opposite polarity to the latent electrostatic image to be developed.
When the developer is brought into contact with the image the toner particles are torn loose from the c~rrier particles by the electrostatic charge of the image and are deposited on the latent image so that it is rendered visible.
Examples of suitable carrier particles are~ inter alia, pulverulent metal such as iron or nickel, metal oxide such as chromium oxide or aluminium oxide and glass, sand or quartz. In practice, metal carrier particles, -- 1 -- , ~3~
particularly iron particles, are widely used. Iron particles are in ~act often used in powder developers for so-called magnetic brush developing in which the developer is transferred to the electrostatic image to be developed with magnetic transfer means in the form of a rotary powder brush.
Developers of the single-component type comprise a toner powder which is either insulating or virtually insulating, i.e., it generally has a specific resistance of >1012~ cm or is made conductive by applying finely divided electrically conductive material to the surface of the powder grains or homogeneously distributing same therein, so that its resistance is generally well below 10 ~ cm. Such developers are generally applied to the latent image to be developed with the aid of a magnetic brush developer system. In that case the toner powder contains a magnetisable iron pigment which can.
also serve as a dye.
Carbon black is generally added to the thermoplastic material as the colouring constituent in the c~se of black toner powders, whereas organic dyes are added in the case of coloured toner powders, e.g. for use in electrographic multi-colour reproduction processes. Knot~ natural or synthetic polymers or resins are used as the thermoplastic material. Examples of suitable thermoplastic materials are polystyrene, copol~ners of styrene with an acrylate and/or methacrylate, polyamides, modified phenol-formaldehyde resins, polyester resins and epoxy resins.
The powder image formed during developing is fixed in the following way. The procedure can take place directly on the surface on which it is formed or after transfer to another receiving surface. Fixing generally takes place by heating with the aid of r~diant heat or by a combination of heating and pressure in a so-called contact fixing apparatus, the powder image being bro~ht into contact with a heated surface such as a roller and/or belt.
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~' 4f~9 Toner powders mainly comprising epoxy resin whose original epoxy groups have been blocked in a given way and in a given percentage are described in the Applicant's Canadian Application Serial No. 277,8G2. The toner powders described therein consist of at least 50% epoxy resin having an epoxy molar mass of at least 10,000 achieved by blocking its original epoxy groups partly by chemical reaction with a monofunctional carboxyllc acid and/or a monofunctional phenol and partly by linking or bonding by means of an intermolecular reaction or by means of a polyfunctional epoxy hardener.
By epoxy molar mass is meant the mass of resin in grams which contains one gram equivalent of epoxy ~see pages 4-14 of "Handbook of Epoxy Resins" by Lee and Neville, McGraw Hill Book Company, 1967).
The above-mentioned toner powders would appear to satisfy the main requirements of a toner powder such as clearly defined polarity, good eharge eharacteristies, adequate ehargeability, uniform eharge distribution, charging stability and low light and temperature sensitivity, good fixing properties, easily reprodueible fixing eharacteristics, thermal stability and good per~anenee during prolonged use.
me glass transition temperature (Tg) and the position of the melting range of the toner powder ean be signifieantly reduced by adding eompounds sueh as those referred to in the Applicant's previously published Dutch Patent Application 74.15325 as co-solvents, i.e., agents for aiding the dissolving of given dyes in epoxy resins~during the preparation of the toner powders described in the Applicant's Canadian Application Serial No.
277,802. In this way it is possible to obtain toner powders whose Tg is only just above the mjnimum limit required for satisfactory use, generally between 45 and 55C, whilst the lo~erlimit of their melting range starts ~ust above the Tg. Such toner powders can be satisfactorily rapidly fixed ~.~
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by a minimum of heat which results in important practical advantages.
However, the Applicant has found that the use of the above co-solvents for the indicated purpose leads to a number of less desirable secondary phenomena.
Even during the preparation of the toner powder to which the co-solvent is added a not inconsiderable proportion thereof evaporates.
Furthermore, during the time the toner powder is in the copying apparatus some of the co-solvent in the toner powder evaporates, resulting in a danger of migration by the charge regulator and dirtying of the copying apparatus and carrier particles.
The present invention provides toner powders based on blocked epoxy resin having a low Tg and whose melting range starts just above the Tg, without it being necessary to use a co-solvent and thus avoiding the above disadvantages.
According to the present invention there is provided a heat-fixable toner powder for developing latent electrostatic images which powder comprises finely divided toner particles comprising colouring constituents, and thermoplastic material substantially comprising epoxy resin having an epoxy molar mass (grams resin/grams equivalent of epoxy) ranging between approximately 2,000 and 7,500, the epoxy resin comprising ~a) a modified epoxy resin (A) obtained by blocking the epoxy groups of an epoxy resin starting material (A') having a molar mass of a maximum of approximately 1,000 and an epoxy molar mass of a maximum of approximately 700, in a proportion of approximately 25~95% by chemical reaction with one or a combination of monofunctional reactants selected from the group consisting of carboxylic acid, phenolic compounds and diaryl sulphonamide, and in '~
a proportion of approximately 5-75% by intermolecular reaction with the hydroxyl groups of the epoxy resin starting material (A') and/or by reaction with an epoxy hardener, or (b) a mixture of at least 20 parts by weight of the modified epoxy resin (A) with a maximum of 80 parts by weight of a phenoxy resin and/or a modified epoxy resin ~B) obtained by an at least 5% blocking of the epoxy groups of an epoxy resin starting material (B') having a molar mass of at least approximately 1,500 and an epoxy molar mass of at least approximately 900 by intermolecular reaction and/or by reaction with an epoxy hardener.
In the present invention the term epoxy resin is understood to mean condensation products of a polyphenol, particularly bisphenol, with a halohydrin and in particular epichlorohydrin. The term phenoxy resins refers to products of the epoxy resin type in the preparation of which 4,4'-isopropy-lidene-diphenol is used as the bifunctional epoxy hardener. In general they have a linear structure and a molar mass between 10,000 and 80,000. One commercially available phenoxy resin is Rùtapox 0717* (molar mass of 30,000) of Messrs. Bakelite.
Examples of epoxy resins with a molar mass of a maximum of l,000 and an epoxy molar mass of a maximum of 700 suitable for producing the toner powder according to the invention are Epikote 1002* ~average molar mass hereinafter M.M., of 1050 and epoxy molar mass hereinafter E.M.M. of 575-700), Epikote 1001* (M.M. 900, E.M.M. 450-500), Epikote 828* (M.M. 370, E.M.M. 184-194) and Epikote 827* (M.M. 360, E.M.M. 180-190).
Examples of epoxy resins with an M.M. of at least approximately 1,500 *Trade mark .
~3~L41~
and an E.M.M. of at least approximately 900 suitable for producing a toner powder according to the invention are Epikote 1004~ (M.M. lLI00, E.M.M. 850-940), Epikote 1006~ (M.M. 2,800, E.M.M. 1550-19nO) and Epikote 1009~ (M.M.
3750, E.M.M. 2300-3400). Epikote is a Shell trade mark and the M.M. and E.M.M. values were supplied by the manufacturer.
In the preparation of a ~ner powder according to the invention preference is given to the use of a modified epoxy resin obtained by blocking the epoxy groups of a liquid epoxy resin with an M.M. of a maximum of approxi~ately 500 and a~ E.M.M. of a maximum of approxi~ately 300 in a proportion of approximately 50-95% by chemical reaction with a monofunctional carboxylic acid, phenol or diaryl sulphonamide and in a proportion of approximately 5-50%
by bonding or linking by means of intermolecular reaction and~or an epoxy hardener.
In this way it is possible to obtain toner powders whose Tg is between appro.ximately 45 and 55C and having a wide melting range beginning immediatelyabove the Iatter value, preferably after mixing the modified epoxy resin described above with phenoxy resin and/or with a modified epoxy resin obtained by blockingthe epoxy groups of an epoxy resin with an M.M. of at least approximately
The present inyention relates to a toner powder suitable for developing latent electrostatic images and which can be fixed by heat, essentially comprising finely divided coloured toner particles which include thermoplastic material, colouring constituents and if desired a charge regulator. The invention more particularly relates to a toner powder whose thermoplastic material mainly comprises epoxy resin, whose original epoxy groups have been blocked in a given manner and in a given percentage. The invention also relates to a process for the preparation of such a toner powder, a two-component developer containing such a toner powder and a single-component developer containing such a toner powder.
Toner powders are widely used in the form of so-called single and two-component developers for making visible latent electrostatic images of the type formed on a suitable surface in electrography or electrophoto-graphy.
Two-component developers have a toner powder whose toner particles contain an insulating thermoplastic material mixed with relatively large carrier particles. By contact with or friction against the carrier particles the toner particles receive an electrostatic charge and consequently adhere to the carrier particles. In general toner and carrier particles are matched to one another in such a way that the toner particles assume a charge having an opposite polarity to the latent electrostatic image to be developed.
When the developer is brought into contact with the image the toner particles are torn loose from the c~rrier particles by the electrostatic charge of the image and are deposited on the latent image so that it is rendered visible.
Examples of suitable carrier particles are~ inter alia, pulverulent metal such as iron or nickel, metal oxide such as chromium oxide or aluminium oxide and glass, sand or quartz. In practice, metal carrier particles, -- 1 -- , ~3~
particularly iron particles, are widely used. Iron particles are in ~act often used in powder developers for so-called magnetic brush developing in which the developer is transferred to the electrostatic image to be developed with magnetic transfer means in the form of a rotary powder brush.
Developers of the single-component type comprise a toner powder which is either insulating or virtually insulating, i.e., it generally has a specific resistance of >1012~ cm or is made conductive by applying finely divided electrically conductive material to the surface of the powder grains or homogeneously distributing same therein, so that its resistance is generally well below 10 ~ cm. Such developers are generally applied to the latent image to be developed with the aid of a magnetic brush developer system. In that case the toner powder contains a magnetisable iron pigment which can.
also serve as a dye.
Carbon black is generally added to the thermoplastic material as the colouring constituent in the c~se of black toner powders, whereas organic dyes are added in the case of coloured toner powders, e.g. for use in electrographic multi-colour reproduction processes. Knot~ natural or synthetic polymers or resins are used as the thermoplastic material. Examples of suitable thermoplastic materials are polystyrene, copol~ners of styrene with an acrylate and/or methacrylate, polyamides, modified phenol-formaldehyde resins, polyester resins and epoxy resins.
The powder image formed during developing is fixed in the following way. The procedure can take place directly on the surface on which it is formed or after transfer to another receiving surface. Fixing generally takes place by heating with the aid of r~diant heat or by a combination of heating and pressure in a so-called contact fixing apparatus, the powder image being bro~ht into contact with a heated surface such as a roller and/or belt.
c~
~' 4f~9 Toner powders mainly comprising epoxy resin whose original epoxy groups have been blocked in a given way and in a given percentage are described in the Applicant's Canadian Application Serial No. 277,8G2. The toner powders described therein consist of at least 50% epoxy resin having an epoxy molar mass of at least 10,000 achieved by blocking its original epoxy groups partly by chemical reaction with a monofunctional carboxyllc acid and/or a monofunctional phenol and partly by linking or bonding by means of an intermolecular reaction or by means of a polyfunctional epoxy hardener.
By epoxy molar mass is meant the mass of resin in grams which contains one gram equivalent of epoxy ~see pages 4-14 of "Handbook of Epoxy Resins" by Lee and Neville, McGraw Hill Book Company, 1967).
The above-mentioned toner powders would appear to satisfy the main requirements of a toner powder such as clearly defined polarity, good eharge eharacteristies, adequate ehargeability, uniform eharge distribution, charging stability and low light and temperature sensitivity, good fixing properties, easily reprodueible fixing eharacteristics, thermal stability and good per~anenee during prolonged use.
me glass transition temperature (Tg) and the position of the melting range of the toner powder ean be signifieantly reduced by adding eompounds sueh as those referred to in the Applicant's previously published Dutch Patent Application 74.15325 as co-solvents, i.e., agents for aiding the dissolving of given dyes in epoxy resins~during the preparation of the toner powders described in the Applicant's Canadian Application Serial No.
277,802. In this way it is possible to obtain toner powders whose Tg is only just above the mjnimum limit required for satisfactory use, generally between 45 and 55C, whilst the lo~erlimit of their melting range starts ~ust above the Tg. Such toner powders can be satisfactorily rapidly fixed ~.~
, , ~3~8~
by a minimum of heat which results in important practical advantages.
However, the Applicant has found that the use of the above co-solvents for the indicated purpose leads to a number of less desirable secondary phenomena.
Even during the preparation of the toner powder to which the co-solvent is added a not inconsiderable proportion thereof evaporates.
Furthermore, during the time the toner powder is in the copying apparatus some of the co-solvent in the toner powder evaporates, resulting in a danger of migration by the charge regulator and dirtying of the copying apparatus and carrier particles.
The present invention provides toner powders based on blocked epoxy resin having a low Tg and whose melting range starts just above the Tg, without it being necessary to use a co-solvent and thus avoiding the above disadvantages.
According to the present invention there is provided a heat-fixable toner powder for developing latent electrostatic images which powder comprises finely divided toner particles comprising colouring constituents, and thermoplastic material substantially comprising epoxy resin having an epoxy molar mass (grams resin/grams equivalent of epoxy) ranging between approximately 2,000 and 7,500, the epoxy resin comprising ~a) a modified epoxy resin (A) obtained by blocking the epoxy groups of an epoxy resin starting material (A') having a molar mass of a maximum of approximately 1,000 and an epoxy molar mass of a maximum of approximately 700, in a proportion of approximately 25~95% by chemical reaction with one or a combination of monofunctional reactants selected from the group consisting of carboxylic acid, phenolic compounds and diaryl sulphonamide, and in '~
a proportion of approximately 5-75% by intermolecular reaction with the hydroxyl groups of the epoxy resin starting material (A') and/or by reaction with an epoxy hardener, or (b) a mixture of at least 20 parts by weight of the modified epoxy resin (A) with a maximum of 80 parts by weight of a phenoxy resin and/or a modified epoxy resin ~B) obtained by an at least 5% blocking of the epoxy groups of an epoxy resin starting material (B') having a molar mass of at least approximately 1,500 and an epoxy molar mass of at least approximately 900 by intermolecular reaction and/or by reaction with an epoxy hardener.
In the present invention the term epoxy resin is understood to mean condensation products of a polyphenol, particularly bisphenol, with a halohydrin and in particular epichlorohydrin. The term phenoxy resins refers to products of the epoxy resin type in the preparation of which 4,4'-isopropy-lidene-diphenol is used as the bifunctional epoxy hardener. In general they have a linear structure and a molar mass between 10,000 and 80,000. One commercially available phenoxy resin is Rùtapox 0717* (molar mass of 30,000) of Messrs. Bakelite.
Examples of epoxy resins with a molar mass of a maximum of l,000 and an epoxy molar mass of a maximum of 700 suitable for producing the toner powder according to the invention are Epikote 1002* ~average molar mass hereinafter M.M., of 1050 and epoxy molar mass hereinafter E.M.M. of 575-700), Epikote 1001* (M.M. 900, E.M.M. 450-500), Epikote 828* (M.M. 370, E.M.M. 184-194) and Epikote 827* (M.M. 360, E.M.M. 180-190).
Examples of epoxy resins with an M.M. of at least approximately 1,500 *Trade mark .
~3~L41~
and an E.M.M. of at least approximately 900 suitable for producing a toner powder according to the invention are Epikote 1004~ (M.M. lLI00, E.M.M. 850-940), Epikote 1006~ (M.M. 2,800, E.M.M. 1550-19nO) and Epikote 1009~ (M.M.
3750, E.M.M. 2300-3400). Epikote is a Shell trade mark and the M.M. and E.M.M. values were supplied by the manufacturer.
In the preparation of a ~ner powder according to the invention preference is given to the use of a modified epoxy resin obtained by blocking the epoxy groups of a liquid epoxy resin with an M.M. of a maximum of approxi~ately 500 and a~ E.M.M. of a maximum of approxi~ately 300 in a proportion of approximately 50-95% by chemical reaction with a monofunctional carboxylic acid, phenol or diaryl sulphonamide and in a proportion of approximately 5-50%
by bonding or linking by means of intermolecular reaction and~or an epoxy hardener.
In this way it is possible to obtain toner powders whose Tg is between appro.ximately 45 and 55C and having a wide melting range beginning immediatelyabove the Iatter value, preferably after mixing the modified epoxy resin described above with phenoxy resin and/or with a modified epoxy resin obtained by blockingthe epoxy groups of an epoxy resin with an M.M. of at least approximately
2,500 and an E.M.M. of at least approximately 2,000 to a minimum extent of 5%
by linking and/or bonding by means of intermolecular reaction and~or an epoxy hardener.
Such toner powders are particularly suitable for use in a high volume copying apparatus with a contact fixing device. Compared with conventional toners such as for example, toners based on styrene-acrylate polymers, they can be excellently fixed at an extremely low temperature in a few hundredths of a second.
The mono~unctional carboxylic acids, phenols or aryl sulphonamides Trade ~ark , : ` ~
.~ .
.
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used for blocking the epoxy resin or resins chosen as the starting product must, apart from ~he carboxyl, hydroxy or amide group, contain no further substituents which, under the conditions prevailing during the modification process, can react with the reactive groups of the epoxy resin.
Carboxylic acids which can be used ~rith particular advantage are aromatic carboxylic acids such as benzoic acid and those substituted by one or more alkyl, aralkyl, cycloaIkyl, aryl, alkylaryl, alkoxy or aryloxy groups and which under the conditions during modification are not or are scarcely volatile. Exa~lples of such carboxylic acids are 2,4-dimethylbenzoic acid, 4-(~,~-dimethylbenzyl?-benzoic acid, 4-phenylbenzoic acid and 4-ethoxy-benzoic acid. However, it is also possible to use aliphatic carboxylic acids such as heptanoic, nonanoic, dodecanoic, isododecanoic, hexadecanoic and octa-decanoic acids.
Examples of suitable phenol compounds are 4-n-butylphenol, 4-n-pentylphenol, 2,3,4,6-tetramethylphenol, 2,3,5,6-tetramethylphenol, 4-(~
dimethyl)-benzylphenol, 4-cyclohexylphenol, 3-methoxyphenol, 4-methoxyphenol and 4-ethoxyphenol. Of the above compounds, particular preference is given to unsubstituted benzoic acid and 4~ -dimethyl)-benzylphenol.
Examples of suitable diaryl-sulphonamides are benzene-sulphonanilide and derivatives thereof, such as those in which one or two benzene nuclei carry one or more lower alkyl or alkoxy groups.
Although it is possible to separately block the epoxy resins chosen as - starting products and then to prepare the toner powder with the aid of modified epoxy resin or mixtures of modified epoxy resins thus obtained~
the blocking can however also take place during the preparation of the toner pot~der, which leads to considerable time and t work ~avings. It has been found that the blocking process can easily be kept under control and can be :
, :
regulated as required. In this way it is possible to obtain a tailor-made toner powder of particularly good quality. Another advantage of such a com-bined preparation process is that when it is desired to prepare a toner powder with a positive charge regulator of the amine type, in m~ny cases the positive charge regulator can also serve to ensure a correct performance of the blocking, thus obviating the necessit~ of a separate catalyst or any other additions.
The toner powder according to the invention can be prepared with the aid of methods generally known for the purpose of preparing toner powders e.g. kneading extrusion or hot melting methods.
In the first two of these methods the resin, the colouring constituents, and if desired other constituents, such as a charge regulator, can be mixed together at temperatures of about 90-130C, whereas in the latter method temperatures of about 150 to 250C are used. After cooling, the material is ground into particles of the desired fineness, usually 2-50 ~m.
Of the three above-defined preparation methods, the hot melting method has proved most suitable for the preparation of the toner powder accord-ing to the invention, particularly if the blocking reactions are to take place during the preparation of the toner powder, which is advantageous for the reasons given hereinbefore. The toner powder prepared by this preferred method appears to have even better properties than when the other two methods are used and this particularly applies to the quality and reproducibility of the charging, stability and fixing behaviour. This is helped by the fact that with the preferred method it is easily possible to control and regulate the tèmperatures and residence times.
If it is desired to prepare a toner powder whose modified epoxy resin is obtained by starting partly with a liquid epoxy resin and partly with ~ , ::
- . :
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a solid epoxy resin, the two resins can be mixed together before performing the blocking reaction. However, it is also possible in a first step to block a certain proportion of the ultimately desired percentage and preferably at least 70-80% thereof of the epoxy groups of the liquid epoxy resin chosen as the starting material by reaction with one of the above-mentioned mono-~unctional blocking agents, preferably in combination with the intermolecular reaction. After this the solid epoxy resin or the mixture of epoxy resins selected as the starting material or materials are added and blocking is per-mitted to take place to the final desired percentage in a second step. m e other desired constituentsare preferably added in the first step in order to obtain maximum homogeneity of mixing.
~ le toner powders according to the invention generally charge in a sufficiently negative manner with respect to conventional carriers such as e.g.
iron powder or iron-coa~ed powder, so that there is no need to add a charge regulator for this purpose. However, if desired a negative charge regulator can be added. A compound which can be used for this purpose is e.g. Atlac 382E (poly-4,4'-isopropylidene-diphenyl-propylene-oxide-fumarate), a trade nark of Atlas Company.
m e toner powder can be mixed with special carriers known for this purpose in order to obtain a two-component developer in which the toner powder according to the invention acquires a positive charge. Such carriers are, for example, described in British Patents Nos. 1,251,752; 1,342,748; 1,373, 000, 1,389,744 and 1,438,973.
Whenever the toner powder according to the invention is mixed with a conventional carrier such as iron, nickel, metal oxide, glass, sand or quartz, the powder must contain a positive charge regulator in order ror it to have a sufficiently positive chargeability. For this purpose it is possible to use _ g _ ~l3~
one of the conventional positi~e charge re~ukators, the best known of which are ~igrosine base and Nigrosine-hydrochloride. HoT~Iever, the preferred positive charge regulator for the toner FoW~er according to the invention is an epoxy amine which is the chemical reaction product of an epoxy resin with a basic amine.
One of the many types of commercially available epoxy resins can be used in the preparation of such epoxy amines.
Ihe epoxy resin chosen as the starting resin preferably has an M.M. of max. 1, 500 and an E.M.M. between 150 and 1,000, examples of such commercial products being Epikote 828, 1001 and 1004~. The epoxy resin chosen as the starting resin is reacted with a basicamine, which must be a primary or a secondary mono- or polyfunctiona~ amine with a pKa-value ~ 3, and prefer-ably between 8 and 11. The functionality of an amine is determined by the number of hydrogen atoms on basic nitrogen atoms in the molecule. For the meaning of the pKa - value, reference should be made to the book "Dissociation Constants of Organic Bases in Aqueous Solution" by the International Union of Pure and Applied Chemistry, 1965 Edition~ pages 1 and 2.
An additional advantage of using an epoxy amine as the positive charge regulator is that by choosing a starting amine with a given pKa - value it is possible to control the chargeability of the toner resin prepared with it within certain limits. This leads to a greater freedom in the choice of the carrier to be used in the developer and an increasing need is being found for this.
In the preparation of the epoxy amine preference is given to the use of substituted or unsubstituted low molecular weight aliphatic amines as well as cycloaliphatic and heterocyclic amines. E~amples of advantageously Usable unsubstituted monofunctional aliphatic amines are dipropyl, diisopropyl~
~Irade mark ~.
- ~ ' .' ,, ~3~
dibutyl, dipentyl and dihexyl amines. P~rticularly good res~lts are obtained with aliphatic hydroxy-alkylamines and in particular 2-methylamino-ethanol and 2,2'-imino-diethanol. Examples of successf'ully tested polyfunctional amines are 2-amino-ethanol, ethylene-diamine, diethylene-triamine and 2,2'-(ethylene-diimino ) -diethanol .
me epoxy amines can be readily mixed with the toner resin due to their structure being closely related to the modified epoxy resin and reveal virtually no migration tendency. As a result the -toner powder prepared there-with has a good uniform charge'ability and a good chargingstability. In view of the fact that they are also virtually colourless, it is possible to prepare therewith positively chargeable toner powders in any desired colour.
The quantitites of epoxy arnine to be used are generally between 0.01 and 1 equivalent base ~g of toner, being inter alia dependent on the carrier to be used in the developer together with the toner powder. With the hitherto used carriers the desired charging level is obtained in most cases if between 0.025 and 0.25 equivalent base in the form of an epoxy amine is present per kg of toner powder.
The toner powder according to the invention can also be used as a single-component developer~'that is without carrier, for the purpose of so-called unitary developing. Preferably there is then utili~ed the magnetic brush developing method in which the toner powder is applied to the surface to be developed by a powder brush formed on the rotary outer surface of a developing roller having a ma~netic core. For this purpose finely divided magnetisable material such as iron particles are homogeneously dispersed in the toner particles. Said material is genercilly intimately mixed with the toner resin during the preparation of the toner powder when it is still in the liquid phase. Iron powder generally represents 30 to 80% by weight based on ~,~
'':
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the resin.
A positive charge regulator is added to the toner powder for use in developing negative electrostatic images.
The invention is further illustrated hereinafter by means of non-limitative Examples.
Example 1 The following constituents are successively introduced into a mixing kettle equipped with a stirrer and oil bath heating;
22.0 g of Epikote 828~ (E.M.M. = 185) 19.0 g of 4- a~a-dimethylbenzyl phenol 6.o g of a reaction product of Epikote 1001* with 2-methylamino-ethanol as the positive charge regulator 6.0 g of carbon.
The mixture was then heated to 180C and stirred at thistemperature for 90 minutes. The phenolic blocking agent quantitatively reacted with the epoxy resin, the residue being smaller than 0.1%. The E.M.M.
of the mixture was 3800, meaning that about 88% of the epoxy groups had reacted. 47.0 g of Epikote 1009* (E.M.M. = 3150) was added and stirring continued for 90 minutes at 200C. The E.M.M. of the mixture was now 4250, meaning that about 82% of all the epoxy groups of the two epoxy resins had reacted. m e cooled charge was ground and sieved giving particles in the range approximately 8 to 24 ~m. The glass transition temperature (Tg) was 51C determined from the D.S.C.-thermogram recorded with the Du Pont 990 thermal analyzer. 4 parts of toner were mi~ed with 96 parts of oxidised iron powder. m e charge was ~ 15uC/g and the permanence was > 100,000 copies.
When using the toner in a copying apparatus under practical conditions, there * Trade mark .. ~ .
, .
-; ' ~
~3~489 were not found to ~e any disadyantageous characteristics ~Ihich could beattributed to the presence of free epoxy groups.
The toner had a very fabourable fixing behaviour.
When used in a copying apparatus with a contact fixing device provided with a silicone rubber-covered roller whose top coating had been previously aged(hereinafter referred to as measuring arrangement A), a fixing ran~e of 75 - 103C (28C) was found in the case of an effective contact time i of 1.6 seconds. The lower limit of the fixing range is the temperature at which the image is just adequately fixed. me upper limit is the temperature at which so-called offset images first occur by transferring the image to the fixing roller and from there back to the paper. The fixing range of a commercially available toner powder based on styrene-butylacrylate copolymer was 102 -133C.
m e toner powder prepared in the m~nner described hereinbefore was per~ectly fixed in a contact fixing apparatus whose silicone rubber roller was covered with a thin coating of silicone oil (hereinafter referred to as measuring arranbement B) with an effective contact time of 0,03 seconds and a contact roller temperature of 165C. A contact roller temperature of 210C was necessary to fix the prior art styrene-butylacrylate copolymer-based toner powder in the same time.
Example 2 e process of Example 1 was repeated but in this case 47 g ofEpikote 1006* (E.M.M. = 1690) was used instead of Epikote 1009.
m e mixing time was 160 minutes and the Tg was 53C.
m e E.M.M. of the toner mixture was 5070 (87% of the epoxy groups had reacted).
me characteristics of the toner were in accordance with those ~Trade mark ..
~3~8~
of Example 1.
Exam~le 3 Example 1 was repeated but in tnis case benzoic acid was used as the blocking agent inst,ead of 4-a,a-dimethylbenzyl phenol. me mixing time after adding the Epikote 1009~ was 40 minutes.
Ingredients:
26.0 g of Epikote 828-~ (E.M.M. = 185 12.0 g of benzoic acid 6.o g of Epilcote 1001~/2-methylamino-ethanol reaction product 6.o g of carbon 50.0 g of Epikote 1009~ (E.M.M. = 3150) me Tg was 49C. rhe E.M.M. was 5600 (i.e. 88% of the epoxy groups had reac`ted).
rhe melting range in measuring arrangement A was 88 - 122C
(34C).
m e lower limit in measuring arrangement B was 171C.
In a developer as described in E,cample 1 the toner polarity was positive.
Exam~le 4 A mixture of:
28.7 g of Epikote 828~ (E.M.M. = 185) 24.3 g of 4-a~a-dimethylbenzyl phenol 6.0 g of Epikote 1001'~/2-methylamino-ethanol reaction product were heated for 90 minutes accompanied by stirring at 180C, after which 41.0 g of Epikote 1009~ (E.M.M. = 3150) were added and mixing continued for 360 minutes at 200 C. m e charge was tra~sferred into a laboratory kneader ~Trade mark I ;
..r and was mixed at the kneading e~uilibriu~ te~erature for 60 minutes with 100 g of magnetite (pigment).
The cooled charge was then ground,subjected to a per se known thermal finishing treatment and sieved to a particle size distribution between approximately 10 and 30 llm. The single-component toner can be used in advantageous manner for developing negatively charged photoconductors (inter alia those based on Zno) and can be fixed on plain paper with the fixing arrangement specified in Example 1 (1.6 seconds contact time) between 93 and 125C.
The toner Tg was 47C.
The E.M.M., based on the organic substance (excluding magnetite) was 5100, i.e., 88% of the epoxy groups had reacted.
Example 5 Example 1 was repeated but with the following ingredients:
25.3 g Or Epikote 828~ (E.M.M. = 185) 21.7 g of 4~ dimethylbenzyl phenol 0.5 g of tetramethyl ammonium chloride 6.o g of carbon 46.5 g of Epikote 1009~ (E.M.M. = 3150) The thermal characteristics of the toner were approximately the same as those of the toner of Example 1. The toner was given a negative polarity when mixed with thermally blued iron powder in a ratio of 96 g iron:
4 g toner.
The Tg was 52C and the E.M.M. 4100.
.... .. ..
Example 6 A toner powder was prepared by mixing during 90 minutes in a ~Trade mark '~'''~.
, ' ' ' mixing vessel:
45.4 g of hpikote 1001~ (E.M.M. = 495) 12.6 g of 4~ -dimethylbenzyl phenol 6.0 g of a reaction product of Epikote 1001~ with 2-methylamino-ethanol 8.o g of carbon.
Thereafter were added:
28.0 g of Epikote 1009~ (E.M.M. = 3500) and subsequently the mixture was stirred at 200C for another 90 minutes. After cooling the charge was ground and sieved giving particles in the range approximately 8 to 25 ~m.
me Tg was 63C and the E.M.M. = 5400 indicating that about 79% of the original epoxy groups originally present in the starting ma-terial had been blocked.
A developing powder comprising 4% by wt. of the toner powder so prepared in admixture with 96% by wt. of an iron powder produced good copies and showed a high permanence during prolonged use. m e toner powder could be fixed at relatively low temperatures and had a high powder stability.
Example 7 Example 1 was repeated, but omitting the blocking agent 4~
dimethylbenzyl phenol. After mixing for two hours a rubbery mixture was obtained which could not be ground and was no longer fixable.
~Trade mark . ~ .
by linking and/or bonding by means of intermolecular reaction and~or an epoxy hardener.
Such toner powders are particularly suitable for use in a high volume copying apparatus with a contact fixing device. Compared with conventional toners such as for example, toners based on styrene-acrylate polymers, they can be excellently fixed at an extremely low temperature in a few hundredths of a second.
The mono~unctional carboxylic acids, phenols or aryl sulphonamides Trade ~ark , : ` ~
.~ .
.
~3~
used for blocking the epoxy resin or resins chosen as the starting product must, apart from ~he carboxyl, hydroxy or amide group, contain no further substituents which, under the conditions prevailing during the modification process, can react with the reactive groups of the epoxy resin.
Carboxylic acids which can be used ~rith particular advantage are aromatic carboxylic acids such as benzoic acid and those substituted by one or more alkyl, aralkyl, cycloaIkyl, aryl, alkylaryl, alkoxy or aryloxy groups and which under the conditions during modification are not or are scarcely volatile. Exa~lples of such carboxylic acids are 2,4-dimethylbenzoic acid, 4-(~,~-dimethylbenzyl?-benzoic acid, 4-phenylbenzoic acid and 4-ethoxy-benzoic acid. However, it is also possible to use aliphatic carboxylic acids such as heptanoic, nonanoic, dodecanoic, isododecanoic, hexadecanoic and octa-decanoic acids.
Examples of suitable phenol compounds are 4-n-butylphenol, 4-n-pentylphenol, 2,3,4,6-tetramethylphenol, 2,3,5,6-tetramethylphenol, 4-(~
dimethyl)-benzylphenol, 4-cyclohexylphenol, 3-methoxyphenol, 4-methoxyphenol and 4-ethoxyphenol. Of the above compounds, particular preference is given to unsubstituted benzoic acid and 4~ -dimethyl)-benzylphenol.
Examples of suitable diaryl-sulphonamides are benzene-sulphonanilide and derivatives thereof, such as those in which one or two benzene nuclei carry one or more lower alkyl or alkoxy groups.
Although it is possible to separately block the epoxy resins chosen as - starting products and then to prepare the toner powder with the aid of modified epoxy resin or mixtures of modified epoxy resins thus obtained~
the blocking can however also take place during the preparation of the toner pot~der, which leads to considerable time and t work ~avings. It has been found that the blocking process can easily be kept under control and can be :
, :
regulated as required. In this way it is possible to obtain a tailor-made toner powder of particularly good quality. Another advantage of such a com-bined preparation process is that when it is desired to prepare a toner powder with a positive charge regulator of the amine type, in m~ny cases the positive charge regulator can also serve to ensure a correct performance of the blocking, thus obviating the necessit~ of a separate catalyst or any other additions.
The toner powder according to the invention can be prepared with the aid of methods generally known for the purpose of preparing toner powders e.g. kneading extrusion or hot melting methods.
In the first two of these methods the resin, the colouring constituents, and if desired other constituents, such as a charge regulator, can be mixed together at temperatures of about 90-130C, whereas in the latter method temperatures of about 150 to 250C are used. After cooling, the material is ground into particles of the desired fineness, usually 2-50 ~m.
Of the three above-defined preparation methods, the hot melting method has proved most suitable for the preparation of the toner powder accord-ing to the invention, particularly if the blocking reactions are to take place during the preparation of the toner powder, which is advantageous for the reasons given hereinbefore. The toner powder prepared by this preferred method appears to have even better properties than when the other two methods are used and this particularly applies to the quality and reproducibility of the charging, stability and fixing behaviour. This is helped by the fact that with the preferred method it is easily possible to control and regulate the tèmperatures and residence times.
If it is desired to prepare a toner powder whose modified epoxy resin is obtained by starting partly with a liquid epoxy resin and partly with ~ , ::
- . :
:~ ~ 3~
a solid epoxy resin, the two resins can be mixed together before performing the blocking reaction. However, it is also possible in a first step to block a certain proportion of the ultimately desired percentage and preferably at least 70-80% thereof of the epoxy groups of the liquid epoxy resin chosen as the starting material by reaction with one of the above-mentioned mono-~unctional blocking agents, preferably in combination with the intermolecular reaction. After this the solid epoxy resin or the mixture of epoxy resins selected as the starting material or materials are added and blocking is per-mitted to take place to the final desired percentage in a second step. m e other desired constituentsare preferably added in the first step in order to obtain maximum homogeneity of mixing.
~ le toner powders according to the invention generally charge in a sufficiently negative manner with respect to conventional carriers such as e.g.
iron powder or iron-coa~ed powder, so that there is no need to add a charge regulator for this purpose. However, if desired a negative charge regulator can be added. A compound which can be used for this purpose is e.g. Atlac 382E (poly-4,4'-isopropylidene-diphenyl-propylene-oxide-fumarate), a trade nark of Atlas Company.
m e toner powder can be mixed with special carriers known for this purpose in order to obtain a two-component developer in which the toner powder according to the invention acquires a positive charge. Such carriers are, for example, described in British Patents Nos. 1,251,752; 1,342,748; 1,373, 000, 1,389,744 and 1,438,973.
Whenever the toner powder according to the invention is mixed with a conventional carrier such as iron, nickel, metal oxide, glass, sand or quartz, the powder must contain a positive charge regulator in order ror it to have a sufficiently positive chargeability. For this purpose it is possible to use _ g _ ~l3~
one of the conventional positi~e charge re~ukators, the best known of which are ~igrosine base and Nigrosine-hydrochloride. HoT~Iever, the preferred positive charge regulator for the toner FoW~er according to the invention is an epoxy amine which is the chemical reaction product of an epoxy resin with a basic amine.
One of the many types of commercially available epoxy resins can be used in the preparation of such epoxy amines.
Ihe epoxy resin chosen as the starting resin preferably has an M.M. of max. 1, 500 and an E.M.M. between 150 and 1,000, examples of such commercial products being Epikote 828, 1001 and 1004~. The epoxy resin chosen as the starting resin is reacted with a basicamine, which must be a primary or a secondary mono- or polyfunctiona~ amine with a pKa-value ~ 3, and prefer-ably between 8 and 11. The functionality of an amine is determined by the number of hydrogen atoms on basic nitrogen atoms in the molecule. For the meaning of the pKa - value, reference should be made to the book "Dissociation Constants of Organic Bases in Aqueous Solution" by the International Union of Pure and Applied Chemistry, 1965 Edition~ pages 1 and 2.
An additional advantage of using an epoxy amine as the positive charge regulator is that by choosing a starting amine with a given pKa - value it is possible to control the chargeability of the toner resin prepared with it within certain limits. This leads to a greater freedom in the choice of the carrier to be used in the developer and an increasing need is being found for this.
In the preparation of the epoxy amine preference is given to the use of substituted or unsubstituted low molecular weight aliphatic amines as well as cycloaliphatic and heterocyclic amines. E~amples of advantageously Usable unsubstituted monofunctional aliphatic amines are dipropyl, diisopropyl~
~Irade mark ~.
- ~ ' .' ,, ~3~
dibutyl, dipentyl and dihexyl amines. P~rticularly good res~lts are obtained with aliphatic hydroxy-alkylamines and in particular 2-methylamino-ethanol and 2,2'-imino-diethanol. Examples of successf'ully tested polyfunctional amines are 2-amino-ethanol, ethylene-diamine, diethylene-triamine and 2,2'-(ethylene-diimino ) -diethanol .
me epoxy amines can be readily mixed with the toner resin due to their structure being closely related to the modified epoxy resin and reveal virtually no migration tendency. As a result the -toner powder prepared there-with has a good uniform charge'ability and a good chargingstability. In view of the fact that they are also virtually colourless, it is possible to prepare therewith positively chargeable toner powders in any desired colour.
The quantitites of epoxy arnine to be used are generally between 0.01 and 1 equivalent base ~g of toner, being inter alia dependent on the carrier to be used in the developer together with the toner powder. With the hitherto used carriers the desired charging level is obtained in most cases if between 0.025 and 0.25 equivalent base in the form of an epoxy amine is present per kg of toner powder.
The toner powder according to the invention can also be used as a single-component developer~'that is without carrier, for the purpose of so-called unitary developing. Preferably there is then utili~ed the magnetic brush developing method in which the toner powder is applied to the surface to be developed by a powder brush formed on the rotary outer surface of a developing roller having a ma~netic core. For this purpose finely divided magnetisable material such as iron particles are homogeneously dispersed in the toner particles. Said material is genercilly intimately mixed with the toner resin during the preparation of the toner powder when it is still in the liquid phase. Iron powder generally represents 30 to 80% by weight based on ~,~
'':
~L3~
the resin.
A positive charge regulator is added to the toner powder for use in developing negative electrostatic images.
The invention is further illustrated hereinafter by means of non-limitative Examples.
Example 1 The following constituents are successively introduced into a mixing kettle equipped with a stirrer and oil bath heating;
22.0 g of Epikote 828~ (E.M.M. = 185) 19.0 g of 4- a~a-dimethylbenzyl phenol 6.o g of a reaction product of Epikote 1001* with 2-methylamino-ethanol as the positive charge regulator 6.0 g of carbon.
The mixture was then heated to 180C and stirred at thistemperature for 90 minutes. The phenolic blocking agent quantitatively reacted with the epoxy resin, the residue being smaller than 0.1%. The E.M.M.
of the mixture was 3800, meaning that about 88% of the epoxy groups had reacted. 47.0 g of Epikote 1009* (E.M.M. = 3150) was added and stirring continued for 90 minutes at 200C. The E.M.M. of the mixture was now 4250, meaning that about 82% of all the epoxy groups of the two epoxy resins had reacted. m e cooled charge was ground and sieved giving particles in the range approximately 8 to 24 ~m. The glass transition temperature (Tg) was 51C determined from the D.S.C.-thermogram recorded with the Du Pont 990 thermal analyzer. 4 parts of toner were mi~ed with 96 parts of oxidised iron powder. m e charge was ~ 15uC/g and the permanence was > 100,000 copies.
When using the toner in a copying apparatus under practical conditions, there * Trade mark .. ~ .
, .
-; ' ~
~3~489 were not found to ~e any disadyantageous characteristics ~Ihich could beattributed to the presence of free epoxy groups.
The toner had a very fabourable fixing behaviour.
When used in a copying apparatus with a contact fixing device provided with a silicone rubber-covered roller whose top coating had been previously aged(hereinafter referred to as measuring arrangement A), a fixing ran~e of 75 - 103C (28C) was found in the case of an effective contact time i of 1.6 seconds. The lower limit of the fixing range is the temperature at which the image is just adequately fixed. me upper limit is the temperature at which so-called offset images first occur by transferring the image to the fixing roller and from there back to the paper. The fixing range of a commercially available toner powder based on styrene-butylacrylate copolymer was 102 -133C.
m e toner powder prepared in the m~nner described hereinbefore was per~ectly fixed in a contact fixing apparatus whose silicone rubber roller was covered with a thin coating of silicone oil (hereinafter referred to as measuring arranbement B) with an effective contact time of 0,03 seconds and a contact roller temperature of 165C. A contact roller temperature of 210C was necessary to fix the prior art styrene-butylacrylate copolymer-based toner powder in the same time.
Example 2 e process of Example 1 was repeated but in this case 47 g ofEpikote 1006* (E.M.M. = 1690) was used instead of Epikote 1009.
m e mixing time was 160 minutes and the Tg was 53C.
m e E.M.M. of the toner mixture was 5070 (87% of the epoxy groups had reacted).
me characteristics of the toner were in accordance with those ~Trade mark ..
~3~8~
of Example 1.
Exam~le 3 Example 1 was repeated but in tnis case benzoic acid was used as the blocking agent inst,ead of 4-a,a-dimethylbenzyl phenol. me mixing time after adding the Epikote 1009~ was 40 minutes.
Ingredients:
26.0 g of Epikote 828-~ (E.M.M. = 185 12.0 g of benzoic acid 6.o g of Epilcote 1001~/2-methylamino-ethanol reaction product 6.o g of carbon 50.0 g of Epikote 1009~ (E.M.M. = 3150) me Tg was 49C. rhe E.M.M. was 5600 (i.e. 88% of the epoxy groups had reac`ted).
rhe melting range in measuring arrangement A was 88 - 122C
(34C).
m e lower limit in measuring arrangement B was 171C.
In a developer as described in E,cample 1 the toner polarity was positive.
Exam~le 4 A mixture of:
28.7 g of Epikote 828~ (E.M.M. = 185) 24.3 g of 4-a~a-dimethylbenzyl phenol 6.0 g of Epikote 1001'~/2-methylamino-ethanol reaction product were heated for 90 minutes accompanied by stirring at 180C, after which 41.0 g of Epikote 1009~ (E.M.M. = 3150) were added and mixing continued for 360 minutes at 200 C. m e charge was tra~sferred into a laboratory kneader ~Trade mark I ;
..r and was mixed at the kneading e~uilibriu~ te~erature for 60 minutes with 100 g of magnetite (pigment).
The cooled charge was then ground,subjected to a per se known thermal finishing treatment and sieved to a particle size distribution between approximately 10 and 30 llm. The single-component toner can be used in advantageous manner for developing negatively charged photoconductors (inter alia those based on Zno) and can be fixed on plain paper with the fixing arrangement specified in Example 1 (1.6 seconds contact time) between 93 and 125C.
The toner Tg was 47C.
The E.M.M., based on the organic substance (excluding magnetite) was 5100, i.e., 88% of the epoxy groups had reacted.
Example 5 Example 1 was repeated but with the following ingredients:
25.3 g Or Epikote 828~ (E.M.M. = 185) 21.7 g of 4~ dimethylbenzyl phenol 0.5 g of tetramethyl ammonium chloride 6.o g of carbon 46.5 g of Epikote 1009~ (E.M.M. = 3150) The thermal characteristics of the toner were approximately the same as those of the toner of Example 1. The toner was given a negative polarity when mixed with thermally blued iron powder in a ratio of 96 g iron:
4 g toner.
The Tg was 52C and the E.M.M. 4100.
.... .. ..
Example 6 A toner powder was prepared by mixing during 90 minutes in a ~Trade mark '~'''~.
, ' ' ' mixing vessel:
45.4 g of hpikote 1001~ (E.M.M. = 495) 12.6 g of 4~ -dimethylbenzyl phenol 6.0 g of a reaction product of Epikote 1001~ with 2-methylamino-ethanol 8.o g of carbon.
Thereafter were added:
28.0 g of Epikote 1009~ (E.M.M. = 3500) and subsequently the mixture was stirred at 200C for another 90 minutes. After cooling the charge was ground and sieved giving particles in the range approximately 8 to 25 ~m.
me Tg was 63C and the E.M.M. = 5400 indicating that about 79% of the original epoxy groups originally present in the starting ma-terial had been blocked.
A developing powder comprising 4% by wt. of the toner powder so prepared in admixture with 96% by wt. of an iron powder produced good copies and showed a high permanence during prolonged use. m e toner powder could be fixed at relatively low temperatures and had a high powder stability.
Example 7 Example 1 was repeated, but omitting the blocking agent 4~
dimethylbenzyl phenol. After mixing for two hours a rubbery mixture was obtained which could not be ground and was no longer fixable.
~Trade mark . ~ .
Claims (18)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A heat-fixable toner powder for developing latent electrostatic images which powder comprises finely divided toner particles comprising colouring constituents, and thermoplastic material substantially comprising epoxy resin having an epoxy molar mass (grams resin/grams equivalent of epoxy) ranging between approximately 2,000 and 7,500, the epoxy resin comprising (a) a modified epoxy resin (A) obtained by blocking the epoxy groups of an epoxy resin starting material (A') having a molar mass of a maximum of approximately 1,000 and an epoxy molar mass of a maximum of approximately 700, in a proportion of approximately 25-95% by chemical reaction with one or a combination of monofunctional reactants selected from the group consisting of carboxylic acid, phenolic compounds and diaryl-sulphonamide, and in a proportion of approximately 5-75% by intermolecular reaction with the hydroxyl groups of the epoxy resin starting material (A') and/or by reaction with an epoxy hardener, or (b) a mixture of at least 20 parts by weight of the modified epoxy resin (A) with a maximum of 80 parts by weight of a phenoxy resin and/or a modified epoxy resin (B) obtained by an at least 5% blocking of the epoxy groups of an epoxy resin starting material (B') having a molar mass of at least approximately 1,500 and an epoxy molar mass of at least approximately 900 by intermolecular reaction and/or by reaction with an epoxy hardener.
2. A toner powder according to claim 1 characterised in that at least 20% by weight of the modified epoxy resin (A) is obtained by blocking the epoxy groups of a liquid epoxy resin with a molar mass of a maximum of approximately 500 and an epoxy molar mass of a maximum of approximately 300 in a proportion of approximately 50 - 95% by chemical reaction with one or a combination of monofunctional reactants, and in a proportion of approximately 5 - 50% by intermolecular reaction and/or by reaction with an epoxy hardener.
3. A toner powder according to claim 2 characterised in that a maximum of 80% by weight of said epoxy resin consists of a phenoxy resin and/or a modified epoxy resin (B) obtained by blocking in a proportion of at least 5% the epoxy groups of an epoxy resin starting material (B') with a molar mass of at least approximately 2500 and an epoxy molar mass of at least approximately 2000 by intermolecular reaction and/or by reaction with an epoxy hardener.
4. A toner powder according to claims 1, 2 or 3 characterised in that 4-.alpha.,.alpha.-dimethylbenzyl phenol is used in the blocking process.
5. A toner powder according to claims 1, 2 or 3 characterised in that a substituted or unsubstituted benzene-sulphonanilide is used in the blocking process.
6. A toner powder according to claim 1 characterised in that the toner particles additionally include a charge regulator.
7. A toner powder according to claim 6 characterised in that the charge regulator is an epoxy amine which is the reaction product of an epoxy resin with a basic amine.
8. A toner powder according to claim 7 characterised in that the epoxy amine is the reaction product of a basic amine and an epoxy resin with a molar mass of a maximum of 1500 and an epoxy molar mass between 150 and 1000.
9. A toner powder according to claim 7 characterised in that the epoxy amine is the reaction product of an epoxy resin and a basic amine with a pKa - value between 8 and 11.
10. A toner powder according to claims 7, 8 or 9 characterised in that the epoxy amine is the reaction product of an epoxy resin and a substituted or unsubstituted aliphatic amine.
11. A toner powder according to claims 7, 8 or 9 characterised in that the epoxy amine is the reaction product of an epoxy resin and a hydroxy-alkylamine.
12. A toner powder according to claims 1, 2 or 3 characterised in that it contains finely divided magnetisable material as the colouring constituent.
13. A toner powder, according to claim 1, characterised in that the modified epoxy resin (A) is prepared from an epoxy resin starting material (A') of lower epoxy molar mass by reaction of at least 25% of epoxy groups of the epoxy resin starting material with a monofunctional carboxylic acid and/or a monofunctional phenolic compound and/or a diarylsulphonamide at a temperature of about 150 - 250°C, with the proviso that during the reaction the carboxylic acid and phenolic compound and diarylsulphonamide are substantially non-volatile and have no substituents which are reactive towards the epoxy groups other than the respective carboxylic and hydroxyl and sulphonamide groups, and optionally, by reaction of no more than 75% of the epoxy groups of the epoxy resin starting material (A') by intermolecular reaction and/or by reaction with an epoxy hardener.
14. A process for preparing the toner powder of claim 1, which comprises the steps of homogeneously mixing the thermoplastic material in a molten state with the colouring constituents, cooling the mass thus obtained, and grinding said cooled mass to the desired degree of fineness, wherein epoxy groups of an epoxy resin of lower epoxy molar mass chosen as starting material (A') are modified with the monofunctional carboxylic acid and/or phenolic compound and/or diarylsulphonamide during said mixing of the ingredients.
15. A process according to claim 14 for the preparation of a toner powder according to claim 1, characterised in that the epoxy resin starting materials (A') or (B') or both are mixed in the liquid state at temperatures between 150 and 250°C with the other desired ingredients, the blocking reactions taking place during the mixing process.
16. A process according to claim 15 for the preparation of a toner powder according to claims 2 or 3 characterised in that initially the epoxy groups of the chosen liquid epoxy resin starting materials (A') or (B') or both are blocked in a certain proportion of the ultimately desired percentage after which the chosen solid epoxy resin starting materials (A') or (B') or both are added and blocking to the ultimately desired percentage takes place.
17. A process according to claim 16 characterised in that the epoxy groups of the chosen liquid epoxy resin starting materials are blocked in a proportion of at least 70 to 80% of the ultimately desired percentage.
18. A two-component developer, characterised in that it contains a toner powder according to claims 1, 6 or 13 together with a carrier with respect to which the toner powder is triboelectrically charged.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7810502 | 1978-10-20 | ||
| NL7810502A NL7810502A (en) | 1978-10-20 | 1978-10-20 | TONER POWDER FOR DEVELOPING ELECTROSTATIC IMAGES. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1131489A true CA1131489A (en) | 1982-09-14 |
Family
ID=19831746
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA333,512A Expired CA1131489A (en) | 1978-10-20 | 1979-08-10 | Toner powder containing an epoxy resin modified by chemical reaction and by intermolecular linking and/or epoxy hardening |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS5555346A (en) |
| AU (1) | AU525369B2 (en) |
| CA (1) | CA1131489A (en) |
| CH (1) | CH651678A5 (en) |
| DE (1) | DE2942114A1 (en) |
| ES (1) | ES478862A1 (en) |
| FR (1) | FR2439419A1 (en) |
| GB (1) | GB2036353B (en) |
| IT (1) | IT1121489B (en) |
| NL (1) | NL7810502A (en) |
| SE (1) | SE435766B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5112715A (en) * | 1990-08-06 | 1992-05-12 | Eastman Kodak Company | Toner compositions containing a multi-purpose additive |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3029317A1 (en) * | 1980-08-01 | 1982-03-04 | Martin 8000 München Lehmann | Posters or displays produced with photosensitive colloid coating - on thermoplastics sheet by exposure and wash off then application of colouring to removed areas |
| JPS5893065A (en) * | 1981-11-28 | 1983-06-02 | Dainippon Ink & Chem Inc | Binder for electrophotographic toner |
| US4415646A (en) | 1982-03-03 | 1983-11-15 | Xerox Corporation | Nitrogen containing polymers as charge enhancing additive for electrophotographic toner |
| JP2697847B2 (en) * | 1988-04-19 | 1998-01-14 | 株式会社リコー | Dry electrophotographic toner |
| US6402313B1 (en) * | 1998-05-06 | 2002-06-11 | Sawgrass Systems, Inc. | Substrate reactive printing process |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1169702A (en) * | 1965-12-13 | 1969-11-05 | Molins Machine Co Ltd | Improvements in or relating to Inks |
| US3907693A (en) * | 1973-05-21 | 1975-09-23 | Rank Xerox Ltd | Liquid developer for electrophotography |
| JPS5926942B2 (en) * | 1976-01-13 | 1984-07-02 | コニカ株式会社 | Toner for electrophotographic development |
| NL7605372A (en) * | 1976-05-20 | 1977-11-22 | Oce Van Der Grinten Nv | TONER POWDER FOR DEVELOPING ELECTROSTATIC IMAGES. |
| NL7711623A (en) * | 1977-10-24 | 1979-04-26 | Oce Van Der Grinten Nv | TONER POWDER FOR DEVELOPING LATENT ELECTROSTATIC IMAGES. |
| JPS5550252A (en) * | 1978-10-09 | 1980-04-11 | Dainippon Ink & Chem Inc | Electrophotographic dry type toner |
-
1978
- 1978-10-20 NL NL7810502A patent/NL7810502A/en not_active Application Discontinuation
-
1979
- 1979-03-22 ES ES478862A patent/ES478862A1/en not_active Expired
- 1979-03-23 JP JP3417279A patent/JPS5555346A/en active Granted
- 1979-08-10 CA CA333,512A patent/CA1131489A/en not_active Expired
- 1979-09-27 AU AU51279/79A patent/AU525369B2/en not_active Ceased
- 1979-10-15 SE SE7908527A patent/SE435766B/en not_active IP Right Cessation
- 1979-10-16 CH CH9289/79A patent/CH651678A5/en not_active IP Right Cessation
- 1979-10-18 DE DE19792942114 patent/DE2942114A1/en active Granted
- 1979-10-18 FR FR7925918A patent/FR2439419A1/en active Granted
- 1979-10-19 GB GB7936353A patent/GB2036353B/en not_active Expired
- 1979-10-19 IT IT69048/79A patent/IT1121489B/en active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5112715A (en) * | 1990-08-06 | 1992-05-12 | Eastman Kodak Company | Toner compositions containing a multi-purpose additive |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2942114C2 (en) | 1988-08-04 |
| IT1121489B (en) | 1986-04-02 |
| JPS5555346A (en) | 1980-04-23 |
| DE2942114A1 (en) | 1980-04-30 |
| FR2439419A1 (en) | 1980-05-16 |
| CH651678A5 (en) | 1985-09-30 |
| SE435766B (en) | 1984-10-15 |
| AU525369B2 (en) | 1982-11-04 |
| ES478862A1 (en) | 1979-07-01 |
| IT7969048A0 (en) | 1979-10-19 |
| SE7908527L (en) | 1980-04-21 |
| AU5127979A (en) | 1980-05-01 |
| GB2036353B (en) | 1982-10-27 |
| NL7810502A (en) | 1980-04-22 |
| GB2036353A (en) | 1980-06-25 |
| JPS649629B2 (en) | 1989-02-17 |
| FR2439419B1 (en) | 1985-03-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |