JP2010139574A - Method for producing wax for toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing wax for toner which attains low temperature fixing, can further suppress contamination in a copying machine or the like caused by wax paper, and can obtain a satisfactory fixed image. <P>SOLUTION: A microcrystalline or an alpha olefin cross-linked wax is subjected to distillation refining treatment by molecular distillation, short process distillation or the like so as to reduce volatile components. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a wax for toner.

  Conventionally, in the toner for copying machines and printers, there has been a demand for speeding up and energy saving of copying machines. In order to cope with this, development of a toner excellent in low-temperature fixability is underway. In order to achieve low-temperature fixing, it is necessary to use a toner having a low melting point as a toner release agent wax, and a toner using a low melting point wax has been proposed (see Patent Document 1).

  However, in copiers using toners using these low melting point waxes, when continuous printing is performed, optical components in the copier are contaminated by wax vapor, causing image defects. Yes.

  In general, paraffin wax having a sharp carbon number distribution and a smaller average carbon number is used as a release agent wax having excellent low-temperature fixability. Although these boiling points are sufficiently high, volatilization occurs when the thermal motion of the wax molecules overcomes the intermolecular force at the surface of the liquid surface in a heated and melted state. Volatility is affected by the vapor pressure and viscosity of the wax.

  In order to suppress the volatilization of the paraffin wax, it is effective to increase the molecular weight, but at the same time, the melting point is increased, resulting in the reverse of the low-temperature fixability. Moreover, although the volatility can be reduced to some extent by removing low-boiling components by distillation purification, the effect is small for the cut rate, which is not a satisfactory level.

Also, it has been proposed to use microcrystalline wax as a countermeasure against wax vapor (see Patent Document 2).
JP 11-327193 A JP 2007-206178 A

  However, in order to obtain a high effect for suppressing wax vapor, it is necessary to use highly purified microcrystalline wax. Moreover, it has a high melting point, and there is a problem in cost and supply amount.

  The present invention has been made in view of the circumstances as described above, achieves low-temperature fixing, can further suppress internal contamination of a copying machine or the like by wax vapor, and can obtain a good fixed image. It is an object of the present invention to provide a method for producing a toner wax.

  The present invention is characterized by the following in order to solve the above problems.

  First: A method for producing a wax for toner, which is a release agent to be blended in a toner, characterized by including a step of subjecting a microcrystalline wax or an alpha olefin crosslinked wax to a distillation purification treatment to reduce volatile components. A method for producing a wax for toner.

  Second: The first method for producing a wax for toner according to the first aspect, wherein the content of normal paraffin by gas chromatographic analysis of the microcrystalline wax after the distillation purification treatment is 80% by mass or less.

  Third: The first method for producing a wax for toner according to the above, wherein the alpha olefin crosslinked wax after the distillation purification treatment has an alpha olefin content by GPC analysis of 25% by mass or less.

  Fourth: The method for producing a toner wax according to any one of the first to third aspects, wherein the distillation purification process is molecular distillation or short-path distillation.

  Fifth: The method for producing a toner wax according to any one of the first to fourth aspects, wherein the wax after the distillation purification treatment has a melting point of 50 to 90 ° C.

  In view of the above-described present situation regarding the wax for the release agent of the toner, the present inventors have made various studies on the low-volatile toner wax that generates less wax vapor. As a result, the present inventors have found that the alpha olefin crosslinked wax has a low volatility like the microcrystalline wax, and that these distilled and purified products are particularly effective, thereby completing the present invention.

  According to the present invention, low-temperature fixing can be achieved, and further, contamination inside a copying machine or the like by wax vapor can be suppressed, and a good fixed image can be obtained.

  Hereinafter, the present invention will be described in detail.

  The method for producing a wax for toner of the present invention is characterized in that a microcrystalline wax or an alpha olefin crosslinked wax is subjected to distillation purification treatment to reduce volatile components.

  The distillation purification process needs to be based on a distillation method in which the condensation surface is disposed within a distance shorter than the mean free path of vapor molecules generated from the heating surface. By applying such a distillation purification process, it is possible to suppress the heat deterioration of the sample. Moreover, since the fractionation accuracy is high, there is an advantage that a high effect can be expected with a low cutting rate. On the other hand, when a method other than the distillation method is applied as a purification process, an event such as decomposition of the sample or coloring due to heat deterioration occurs. Moreover, the precision of fractional distillation is low, and it is necessary to raise the cut rate more than necessary. As the distillation purification treatment, molecular distillation and short path distillation are particularly preferable.

  In addition, when a distillation purification process is applied to paraffin wax, in order to reduce the amount of volatile components by half, it is necessary to set the low boiling point component cut rate to about 40% by mass, resulting in poor efficiency. On the other hand, when the distillation purification treatment is applied to the microcrystalline wax or the alpha olefin crosslinked wax as in the present invention, the amount of the volatile component is halved with a cut rate of about several mass% in addition to the small amount of the volatile component itself. Can greatly improve efficiency.

  In the present invention, from the viewpoint of increasing production efficiency and sufficiently reducing volatile components, it is preferable to remove (cut) 3 to 20% by mass of distillate by distillation purification treatment in the case of microcrystalline wax. In the case of an alpha olefin crosslinked wax, it is preferable to remove (cut) 5 to 20% by mass of a distillate by distillation purification treatment.

  In the present invention, the microcrystalline wax preferably has a normal paraffin content by gas chromatographic analysis of 80% by mass or less after the distillation purification treatment. Regarding the volatilization, the molecular weight of the wax has an effect, and the higher the molecular weight, the more difficult it is to volatilize, but the lower the normal paraffin content, the lower the volatility, but the lower the volatility. This is presumably because the increase in viscosity due to branching and cyclic components hinders the diffusion of low molecular weight molecules to the liquid surface. When the normal paraffin content exceeds 80% by mass, the ratio of the actual volatile component to the low molecular weight content becomes extremely large.

  Specific examples of the microcrystalline wax that is subject to distillation purification in the present invention include Hi-Mic-1045, Hi-Mic-1070, Hi-Mic-1080, Hi-Mic-1090 and the like manufactured by Nippon Seiwa. It is done.

  In the present invention, the alpha olefin crosslinked wax preferably has an alpha olefin content of 25% by mass or less by GPC analysis. When the alpha olefin content exceeds 25% by mass, the amount of volatile components increases, and the cut rate in the distillation purification treatment increases, which is not efficient.

  In the present invention, the alpha olefin cross-linked wax to be subjected to distillation purification treatment is a wax obtained by cross-linking an alpha olefin mainly having 20 to 60 carbon atoms in the presence of an organic peroxide. WEISSEN-0372, WEISSEN-0672, etc. are listed.

  In the present invention, the melting point of the wax after the distillation purification treatment is preferably 50 to 90 ° C. When the melting point is less than 50 ° C., thermal aggregation tends to occur when blended with the toner, and storage stability may be reduced. On the other hand, if the melting point exceeds 90 ° C., the fixing temperature becomes high and low-temperature fixing may be difficult.

  In the present invention, the melting point of the wax is a value measured at a micro melting point (JIS K 2235-5.3.2) for microcrystalline wax and at a softening point (JIS K-2207-6.4) for alpha olefin crosslinked wax.

  The wax after the distillation purification treatment may be used alone as a toner wax, or may be used in combination with another low-volatile wax as a toner wax. In addition, when added to paraffin wax, a dramatic effect cannot be expected, but since volatile components can be relatively reduced, they can be used together for the purpose of reducing the volatility of paraffin wax.

  As the toner fixing resin used together with the toner wax produced according to the present invention, those generally used as toner fixing resins can be used. Specific examples thereof include styrene / acrylic resins, polyester resins, Examples thereof include polyolefin resins having a cyclic structure.

  Specific examples of styrene / acrylic resins include styrene / acrylic acid copolymers, styrene / diethylamino / ethyl methacrylate copolymers, styrene / butadiene / acrylic acid ester copolymers, styrene / methyl methacrylate copolymers, and styrene. Examples thereof include butyl methacrylate copolymer, styrene / butyl methacrylate / maleic anhydride copolymer, and styrene / butyl methacrylate / acrylic acid copolymer.

  The following can be mentioned as a copolymerization monomer of a polyester resin. Specific examples of the acid component include malonic acid, succinic acid, glutaric acid, dimer acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydroterephthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, dimethyltetrahydrophthalic acid, naphthalenetetra Examples include carboxylic acid, trimellitic acid, and pyromellitic acid. These may be used alone or in combination of two or more. Specific examples of the alcohol component include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, isopentyl glycol, hydrogenated bisphenol A, 1,3-butanediol, 1,4-butanediol, Examples include trimethylolpropane and pentaerythritol. These may be used alone or in combination of two or more.

  Specific examples of the polyolefin resin having a cyclic structure include a copolymer of an alpha olefin such as ethylene, propylene and butylene and an alicyclic compound having a double bond such as cyclohexene and norbornene.

  The method for producing the toner using the wax produced according to the present invention is not particularly limited. For example, the pulverization method by melt kneading, suspension polymerization method, emulsion polymerization method, miniemulsion polymerization aggregation method, polyester chain elongation And other known methods.

  The toner using the wax produced according to the present invention may be either a monochrome toner or a color toner, and contains a colorant depending on the use of the toner. As the colorant, commonly used pigments and dyes can be used.

  The toner fixing method using the wax produced according to the present invention is not particularly limited, and examples thereof include an oven-type fixing method, a flash-type fixing method, a heating / pressure fixing method, and other known methods. Can be mentioned.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.

Measurement methods and preparation methods in the following Examples and Comparative Examples are as follows.
[Normal paraffin content]
The wax sample was dissolved in isooctane so as to have a concentration of 1 mg / ml, and measurement was performed by a gas chromatograph apparatus (6890N manufactured by Agilent Technologies) equipped with a capillary column. The percentage of the peak area of linear saturated hydrocarbons relative to the sum of all the peak areas of the chromatographic chart obtained with the FID detector was calculated and used as the normal paraffin content.
[Low molecular weight content]
Measurement was performed with a gas chromatograph apparatus in the same manner as described above, and the percentage of the peak area of the low molecular weight component having 30 or less carbon atoms relative to the sum of all peak areas on the gas chromatogram chart was calculated to obtain the low molecular weight content.
[Alpha olefin content]
The alpha olefin cross-linked wax was dissolved in tetrahydrofuran to a concentration of 1 mg / ml, and measurement was performed by gel permeation chromatography (TOSOH HLC-8120GPC) maintained at 40 ° C. The percentage of the peak area of the unreacted component having a molecular weight of 1500 or less in terms of polystyrene relative to the total peak area of the entire chromatographic chart obtained by the RI detector was calculated as the alpha olefin content.
[Weight loss rate]
By weight loss analysis (TG / DTA 2020 manufactured by Seiko Denshi Kogyo Co., Ltd.), the weight loss rate was measured when holding was performed at 250 ° C. and 300 ° C. for 1 hour. Since the actual sample temperature was 216 ° C. at a setting of 250 ° C. and 264 ° C. at a setting of 300 ° C., the weight loss rate was 216 ° C. and the weight loss rate was 264 ° C., respectively. The measurement was performed for each of the wax alone and the resin kneaded product.
[Resin kneaded product]
A sample was obtained by kneading 100 parts by mass of a styrene / acrylic resin (SBM-73 manufactured by Sanyo Chemical Industries) and 5 parts by mass of wax with a small biaxial kneader (HAAKE minilab) at 115 ° C. and 100 rpm for 30 minutes.
Example 1
Microcrystalline wax (Hisei Mic-1080, manufactured by Nippon Seiwa) was distilled using a centrifugal molecular distillation device (MS-380, manufactured by Nippon Vehicle Co., Ltd.) at 210 ° C. and 0.2 Pa. Distillate (approximately 5% by mass) A cut sample was obtained. With respect to this sample, the weight loss rate of the wax alone and the resin kneaded product was measured.
(Example 2)
Alpha olefin cross-linked wax (WEISSEN-0373 manufactured by Nippon Seiwa) was distilled using the above centrifugal molecular distillation apparatus at 200 ° C. and 0.2 Pa to obtain a sample obtained by cutting the distillate (about 7% by mass). . With respect to this sample, the weight loss rate of the wax alone and the resin kneaded product was evaluated.
(Comparative Example 1)
A sample obtained after kneading only a styrene / acrylic resin with a small biaxial kneader was used as a sample. The weight loss rate was measured for this sample.
(Comparative Examples 2 and 3)
Paraffin wax (Nippon Seiwa Wax HNP-11, HNP-9) was used as a sample, and the weight loss rate of the wax alone and the resin kneaded product was measured for this sample.
(Comparative Example 4)
Paraffin wax (HNP-9 manufactured by Nippon Seiwa) was distilled using the above centrifugal molecular distillation apparatus under the conditions of 210 ° C. and 0.2 Pa to obtain a sample obtained by cutting the distillate (about 38% by mass). With respect to this sample, the weight loss rate of the wax alone and the resin kneaded product was measured.
(Comparative Example 5)
Using a molecular distillation purified product of Fischer-Tropsch wax (FNP-0090 manufactured by Nippon Seiwa) as a sample, the weight loss rate of the wax alone and the resin kneaded product was measured.
(Comparative Examples 6-8)
Microcrystalline wax (Nippon Seiwa Hi-Mic-1045, Hi-Mic-1080, Hi-Mic-1090) was used as a sample, and the weight loss rate of the wax alone and the resin kneaded product was measured for this sample.
(Comparative Examples 9 and 10)
Alpha olefin crosslinked waxes (WEISSEN-0373 and WEISSEN-0672 manufactured by Nippon Seiwa) were used as samples, and the weight loss rate of the wax alone and the resin kneaded product was measured for these samples.

  Table 1 shows the measurement results of the melting point, normal paraffin content, low molecular weight content, alpha olefin content, wax alone and the weight loss rate of the resin kneaded product in the examples and comparative examples.

  In the measurement of the weight loss rate, 264 ° C. was not realistic because the measurement temperature was too high, but it was measured for the purpose of confirming the effect when the temperature fluctuated and clearly showing the difference between the waxes. The result of the heat loss analysis with the wax alone has a high correlation between the measurements at 216 ° C. and 264 ° C., and it can be said that the influence of the measurement temperature is small.

  From Table 1, the resin kneaded product has a volatile component in the resin of Comparative Example 1 alone. Moreover, although the weight loss rate becomes larger than resin alone depending on the wax, the weight loss rate may decrease by kneading the wax.

  In the normal paraffins of Comparative Examples 2 and 3, it can be said that the weight loss rate of the wax alone is high and the volatility is high. The weight loss rate in the resin kneaded product is also higher than that of the resin alone.

  In the normal paraffin molecular distillation processed product of Comparative Example 4, the weight loss rate is halved compared to Comparative Example 2, but a considerably high cut rate is required. In the kneaded product with the resin, the weight loss rate was slightly lower than that of Comparative Example 2, but higher than that of the resin alone.

  The molecular distillation-treated product of Fischer-Tropsch wax of Comparative Example 5 is good because the weight loss rate of the wax alone is low. Also in the resin kneaded product, it is not higher than the weight loss rate of the resin alone and is good. However, the melting point is 90 ° C. or higher.

  In the case of normal paraffin containing Fischer-Tropsch wax, those having a high overall molecular weight and a low content of low molecular weight components have low volatility. For this reason, in the raw material selection, the manufacturing process, the post-treatment molecular distillation treatment, etc., it is necessary to considerably narrow down the low molecular weight components, and the efficiency is lowered. Further, since the melting point becomes high, the result is reversed from the purpose of low-temperature fixability.

  In the microcrystalline waxes of Comparative Examples 6 to 8, the low molecular weight content is relatively high, but the weight loss rate with the wax alone is considerably low, which is good. A polymer having a high molecular weight and a low low molecular weight content as in Comparative Example 8 is good, but in the production of microcrystalline wax, the yield of such a wax becomes extremely low. In the resin kneaded product, the value is lower than the weight loss rate of the resin alone. When the resin kneaded material is melted, it is considered that the wax having a lower viscosity than the resin is repelled by the thermal motion of the resin molecular chain and is localized on the resin surface. If the wax itself is highly volatile like normal paraffin, the weight loss rate is high, but if it is low volatile like microcrystalline wax, there is also an effect of suppressing the low boiling point component of the resin by surface coating, It is thought that the weight loss rate will be lower.

  In Example 1, the distillate was cut by about 5% by mass from the microcrystalline wax of Comparative Example 7 by molecular distillation, but the weight loss rate of the wax alone was halved compared with Comparative Example 7, It is running low. Also in the resin kneaded product, the reduction in weight loss is large.

  In Comparative Example 9, the alpha olefin crosslinked wax of Comparative Examples 9 and 10 has a low degree of crosslinking and a large content of unreacted components, compared with the normal paraffins of Comparative Examples 2 to 4, the weight loss rate of the wax alone is lower. It is good in that the weight loss rate in the resin kneaded product is reduced. However, when compared with the microcrystalline waxes of Comparative Examples 6 to 8, the weight loss rate of the wax alone is higher. On the other hand, in Comparative Example 10 having a high degree of crosslinking and few unreacted components, good results were obtained. However, a wax having a high degree of cross-linking has a high melt viscosity, and depending on the toner formulation, there is a concern that fixing defects such as an offset phenomenon may occur.

  In Example 2, about 7% by mass of a distillate was cut from the alpha olefin crosslinked wax of Comparative Example 9 by molecular distillation, but the weight loss rate of the wax alone was significantly lower than that of Comparative Example 9. The weight loss rate in the resin kneaded product is also low.

  As is apparent from the above results, the normal paraffins of Comparative Examples 2 to 5 have many volatile components, and it is difficult to solve problems in the distillation treatment. The microcrystalline wax and the alpha olefin crosslinked wax of Comparative Examples 6 to 10 are low volatility and good waxes. However, in order to suppress volatile components as much as possible, highly refined and highly denatured are necessary. There's a problem.

  On the other hand, the distilled products according to the present invention of Examples 1 and 2 are effective because the volatile components can be significantly reduced by a light treatment. In addition, the volatility of the wax alone is low, and in the kneaded product with the resin, an effect of suppressing the volatilization of the low-boiling component contained in the resin can be expected. That is, since the generation of vapor in the copying machine can be suppressed as much as possible, it is possible to solve the problem that optical system components and the like are contaminated and image defects occur.

Claims (5)

  A method for producing a wax for toner, which is a release agent to be blended in a toner, comprising a step of subjecting a microcrystalline wax or an alpha-olefin cross-linked wax to a distillation purification treatment to reduce volatile components. Manufacturing method.   The method for producing a wax for toner according to claim 1, wherein the normal paraffin content of the microcrystalline wax after the distillation purification treatment is 80% by mass or less by gas chromatographic analysis.   2. The method for producing a wax for toner according to claim 1, wherein the alpha olefin crosslinked wax after the distillation purification treatment has an alpha olefin content of 25% by mass or less by GPC analysis.   The method for producing a toner wax according to any one of claims 1 to 3, wherein the distillation purification treatment is molecular distillation or short-path distillation.   The method for producing a toner wax according to any one of claims 1 to 4, wherein the melting point of the wax after the distillation purification treatment is 50 to 90 ° C.