JPH041209A - Separation of wax from solid wax by solvent extraction - Google Patents

Abstract

PURPOSE:To separate a wax of a different melting point, i.e., molecular weight from a solid starting wax by performing solid-liquid contact between a solid wax selected between a Ziegler synthetic wax and a paraffin wax and a solvent which can dissolve the solid wax at a temperature lower than its melting temperature and removing the solvent from the separated solution. CONSTITUTION:A raw wax which is a low polymer produced as a by-product in the production of polyolefin by the Ziegler process or a petroleum paraffin wax and a solvent which can dissolve this starting wax at a temperature lower than its melting temperature (e.g. toluene or methyl ethyl ketone) are subjected to solid-liquid contact. The solvent is evaporated from the separated solution to separate one or more waxes of different molecular weights. Waxes of different melting points, i.e.), molecular weights can be obtained from the solid starting wax. The obtained product has a sharp melting point, a high latent heat of melting, good heat stability and chemical stability and is useful in the fields including heat-storage materials, thermosensors, heat-sensitive papers, thermal transfer inks, hot melt adhesives, etc.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for separating and producing waxes having different melting points or molecular weights from a solid raw material wax.

[Conventional technology]

There is a demand for producing waxes with different melting points, that is, molecular weights, by using low polymers (abbreviated as Ziegler synthetic wax in the present invention) or petroleum paraffin wax (abbreviated as paraffin wax) that is a by-product during the production of polyolefins by the Ziegler process. Strong in industry. Since Ziegler synthetic wax and paraffin wax are mixtures of multiple components, by separating and refining them, it is possible to produce waxes with different melting points, that is, molecular weights, from the raw material medium. Conventionally, paraffin wax or Ziegler synthetic wax is mixed with a solvent, the temperature is raised to once dissolve everything, and then cooled.
A method has been proposed in which the sequentially deposited wax is separated and produced.

[Problem to be solved by the invention]

However, in this conventional method, it is necessary to separate the precipitated wax and the solution by filtration. Since the precipitated wax is in the form of a gel, filtration is not easy, and this filtration process poses an industrial problem. An object of the present invention is to provide a method for easily producing one or more types of waxes having different melting points or average molecular weights from raw material wax such as Ziegler synthetic wax or paraffin wax.

[Means to solve the problem]

The present invention uses any solid wax selected from Ziegler synthetic wax or paraffin wax as a raw material wax, brings it into solid-liquid contact with a solvent that melts the solid wax at a temperature lower than the melting temperature of the raw material wax, and then separates the solid wax from the solution. This method consists of evaporating and removing the solvent, and by this means, we have developed a method for separately producing waxes with different melting points, ie, average molecular weights, from raw waxes. The wax that is the raw material of the present invention is any solid wax selected from Ziegler synthetic waxes or paraffin waxes. These are usually multicomponent bodies with a considerable molecular weight distribution. Further, a wax that is solid at least at the temperature at which it is brought into contact with the solvent described below is used. Raw wax is filtered to remove impurities. Alternatively, materials obtained by distillation to remove low molecular weight substances can also be used as the raw material of the present invention. If the shape of the wax used is too large or thick, it will be difficult to extract the desired wax component from the raw material medium. For example, it is necessary to increase the contact time. On the other hand, if the wax is in the form of a fine powder, thin flakes, or tablets, it may be crushed into fine powder during the extraction operation, and the unprocessed raw material solid wax may be mixed into the solvent. It also causes clogging of screens, filter cloths, etc. used for filtration. Therefore, it is usually preferable to use wax in the form of spheres or pellets with a diameter of 10 m or less, or flakes or tablets with a thickness of 5 mm or less; Wax in the form of wax or tablets becomes powder during the extraction process, and using spherical or pellet wax with a diameter of one door or less as a raw material means that the raw wax may be mixed into the solvent as it is, or it may be mixed with the mesh used for filtration or This is not desirable as it will clog the mesh of the filter cloth. Toluene,
Aromatic hydrocarbons such as xylene, methyl ethyl ketone,
Aliphatic ketones such as methyl isobutyl ketone, n-
Examples include aliphatic hydrocarbons such as paraffin and isoparaffin that are liquid at a temperature below the melting temperature of the raw material wax, such as n-hexane, n-octane, light oil distillate from petroleum, and kerosene distillate. In addition to these, any solvent can be used as long as it has the ability to dissolve the wax component from the solid wax. However, in consideration of solubility and operability of solvent removal after solid-liquid contact, aromatic hydrocarbons such as toluene and xylene, and ketones such as methyl ethyl ketone and methyl isobutyl ketone are preferred. It is also possible to mix these solvents and use them as a mixed solvent. When making solid-liquid contact with a solvent, heat it to an appropriate temperature,
It is important that the raw material wax is in a solid state. If the temperature is higher than the temperature at which the raw wax itself melts, the raw wax will simply dissolve in the solvent, making it impossible to obtain a wax product different from the raw wax.) A specific solid-liquid contact method is to shower the raw wax in a suitable container with a heated solvent and bring it into contact.
Methods such as draining the solvent after immersion for a predetermined time, supplying and discharging the solvent after immersion for a predetermined time, and furthermore, circulating the immersion liquid and then cleaning with a new solvent can be adopted. After the solid-liquid contact, the solvent is removed by evaporation from the solution containing the wax component in accordance with a conventional method, and the waxes having different melting points, that is, average molecular weights are separated and recovered from the raw material medium. On the other hand, the evaporated solvent can also be recovered and recycled.

[Effect]

Since solid wax is subjected to solid-liquid contact extraction with a solvent at a temperature lower than the temperature at which all of the raw wax melts, only the wax having a melting point corresponding to the temperature of the solvent is eluted from the multicomponent raw material medium. Therefore, molecular weight fractionation based on its melting point is possible.
By selecting the type of solvent, n-paraffin and 1s
The ratio with o-paraffin can also be changed. Wax with a melting point higher than the solvent temperature remains in the solid raw material wax, so conventional Ziegler synthetic wax or paraffin wax is
After mixing with a solvent and raising the temperature to dissolve everything,
Unlike gels produced by cooling and sequentially depositing waxes, separation from the solvent is extremely quick and easy. In particular, the residual solid becomes a porous pumice-like solid consisting only of the high melting point wax as the low melting point wax elutes, resulting in the effect of further increasing the efficiency of single fraction elution. When raw wax is made into flakes, tablets, or pellets to the extent that they can be easily separated and subjected to solvent extraction, it can be efficiently melted and extracted in a short time. Molecular weight fractionation is possible by extraction while increasing the temperature of the solvent stepwise.

【Example】

The present invention will be explained in detail below with reference to Examples. Example 1 320 g of Ziegler synthetic wax A with a melting point of 86°C in the form of flakes with a thickness of about 2 mm was placed in a container, toluene 2Q at a temperature of 10°C was added, and while maintaining the same temperature, gentle stirring was continued for 2 hours for extraction. After that, extract the toluene solution. Next, 2 ρ of toluene at a temperature of 20° C. is newly added, and stirring is continued for 2 hours while maintaining the same temperature, and then the toluene solution is extracted. This is designated as the second eluate. Furthermore, the same operation was repeated to elute at every 10°C from the extraction temperature of 30°C to 90°C to obtain the 3rd to 9th eluted fractions. These eluted fractions were each distilled separately to remove the solvent toluene, and the melting point, average carbon number, melting energy, n-paraffin content, and yield of the remaining wax components were measured. The results are shown in Table 1. Below is Table 1 in the margin: Melting point; DSC peak temperature average carbon number;
Melting energy by gas chromatography; p
n-paraffin content by sc; Table 2 shows the distribution of paraffin carbon numbers in the first to fifth elutions by gas chromatography. Example 2 220g of Ziegler synthetic wax B in the form of a tablet with a thickness of about 3a++ and a melting point of 82.6°C was placed in a cylindrical container with a fine wire mesh at the bottom, and 2Ω of methyl isobutyl ketone at a temperature of 50°C was poured into the container. After extraction by circulating for 3 hours while maintaining the temperature, the methyl ethyl ketone solution is extracted. This is designated as the first eluate. Next, fresh 2Ω of methyl ethyl ketone is circulated at a temperature of 60° C. for extraction, and then extracted and used as the second eluate. The same operation was repeated at 70°C and 80°C to obtain third and fourth eluted fractions. Each eluate was separately distilled to remove the solvent methyl ethyl ketone, and the yield and melting point of the remaining wax were measured. The results are shown in Table 3. Table 2 Table 3 Example 3 330 g of paraffin wax in the form of flakes with a melting point of 56.7°C and a thickness of approximately 2 mm was placed in a container, methyl isobutyl ketone IQ at a temperature of 30°C was added, and while maintaining the same temperature, 1 After continuing to stir gently for some time, the methyl ethyl ketone solution is extracted and used as the first eluate. Next, a new 40℃
of methyl ethyl ketone IQ was added, stirring was continued for 1 hour while maintaining the same temperature, and then the methyl ethyl ketone solution was extracted. This is designated as the second eluate. Further, the same operation was repeated to obtain a third elution fraction with an extraction temperature of 50°C. Each of these eluates was separately distilled to remove the solvent methyl ethyl ketone, and the melting point, average molecular weight, and yield of the remaining medium were measured. The results are shown in Table 4. Table 4 According to the method of the present invention, it is possible to easily produce a wide variety of waxes having various melting points or molecular weights from a multicomponent wax having a molecular weight distribution. In particular, the method of the present invention maintains the extracted wax in its original form, making it easy to separate it from the extracted solution, and eliminating the need to precipitate wax from the solution. There is no need to process
This method is industrially extremely advantageous because it simplifies the process, shortens operation time, and improves the quality of the resulting product. In particular, the resulting product has a sharp melting point, high latent heat of fusion, good thermal stability, and chemical stability, so it can be used in the fields of heat storage materials, thermosensors, thermal paper, thermal transfer inks, and hot melt adhesives. Useful. As is clear from the above examples, one or more types of product waxes having different melting points, that is, different average molecular weights, could be easily produced from the raw material wax.

【Effect of the invention】

Applicant: Japan Wax Polymer Development Institute Co., Ltd. Sakura Co., Ltd. Tomotsunega, Patent Attorney, Hiroshi Mori, Third Department Procedural Amendment (Relationship with the case of the person making the amendment (1)) Address

Claims (1)

[Scope of Claims] 1. Low polymer raw material wax or petroleum paraffin wax that is a by-product during the production of polyolefin by the Ziegler process, a solvent and a solid liquid that melt the raw material wax at a temperature lower than the melting temperature of the raw material wax. 1. A method for separating wax by solvent extraction from solid wax, which comprises contacting the solid wax, and then evaporating the solvent from the separated solution to separate it into one or more types of waxes having different molecular weights. 2. When extracting raw material wax with a solvent, the shape of the raw material wax to be extracted is in the form of flakes or tablets with a thickness of 5 mm or less and 0.2 mm or more, or in the form of spheres or pellets with a diameter of 10 mm or less and 1 mm or more.Claim 1 A method for separating wax by solvent extraction from solid wax as described.