JP2610061B2 - Method for producing fractionated wax having narrow crystal melting temperature range from solid wax - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention is directed to a method in which a solid raw material wax is subjected to distillation, and furthermore, its melting point is separated into a plurality by melting liquid crystal precipitation or crystal separation of the distillate. A method for producing a wax fraction having excellent characteristics, comprising a thermal paper (including a thermal transfer ribbon),
The present invention relates to a method for producing a wax useful for a thermosensor, a hot melt adhesive, and the like.

2. Description of the Related Art and Problems to be Solved

There is a strong demand in the industry for low molecular weight polyolefins, coal-based synthetic waxes, synthetic waxes such as Fischer-Tropsch wax, petroleum-based paraffin wax, and natural waxes. . In particular, in recent years, waxes having a small melting point width, that is, a wax having a small width between a melting start temperature and a melting completion temperature and a large melting energy are strongly demanded for heat sensors, thermal papers, heat storage materials, hot melt adhesives, and the like. ing. However, at present, low-polymerization degree polyolefins of the Ziegler method, that is, low-polymerization degree polyethylene produced as a by-product during the production of polyethylene, or ethylene or low-polymerization degree polyethylene polymerized as a main component thereof meet the above-mentioned industrial requirements. It is very unsatisfactory, especially in the melting point width. Conventionally, petroleum-based waxes having several melting points have been provided by solvent fractionation, but there are difficulties in various desired melting points, their melting point widths, and the like, and further, in their production methods. For example, a recrystallization method using an organic solvent and a sweating method have been proposed. In the solvent recrystallization method, it is necessary to use various amounts of the solvent and separate the precipitated crystals from the solution. The precipitated wax is in a gel state, and the excess is not easy, and this excess process is an industrial problem. A method has been proposed in which solvent extraction is performed in solid-liquid and then the solvent is removed (Japanese Patent Publication No. 48-13992), but there is a drawback that the melting temperature range of the extract is wide. In addition, the sweating method has many problems, such as complexity of the production method by high-temperature time treatment and the like, and the purity of the obtained fractionated wax. Therefore, a technique for providing various waxes whose melting behavior was satisfied with the requirements, and a wax having a desired melting point and a specific melting behavior that satisfied the requirements for use of the wax,
It is currently not provided. In particular, from the low polymerization degree polyolefin wax by-produced during the production of polyolefins such as polyethylene, to obtain a fractionated wax having a different molecular weight of the wax, in particular, the technology to provide the high-performance wax described above, and such No high performance fractionating wax is known. An object of the present invention is to provide a raw material such as synthetic Ziegler wax or paraffin wax which differs in melting point, that is, average molecular weight.
It is an object of the present invention to provide a wax fraction having excellent thermal properties of two or more types (referred to as a fractionated wax in the present invention) by a simple production method.

[Means for Solving the Problems]

The inventor of the present invention has studied diligently the molecular weight fractionation of wax, that is, low molecular weight polymer (distillation from one having a broad molecular weight distribution to one having a narrow molecular weight distribution) by a combination of distillation and fusion liquid crystal deposition. It is very efficient to fractionate into various melting points, and more surprisingly, the fractionated wax has a large melting energy, which is recently required in thermal paper (including thermal transfer ribbons) and others. Further, they have found that the melting behavior is sharp, that is, the melting temperature range is narrow, and the present invention has been accomplished. The present invention is a low-polymerization degree polyethylene having ethylene as a main component, other synthetic wax, petroleum paraffin wax, solid wax such as natural wax, distillation method, the peak carbon number of about 10 to 70 fractionated by a combination of melt liquid crystal deposition. Fractional wax having a melting peak temperature of −35 ° C. to 100 ° C. by a differential scanning calorimeter, and a crystal melting heat of 150 J / g to 300 J / g, preferably 170 to 280 J / g. There is provided a method for producing a fractionated wax having a narrow melting temperature range having a plurality of fractionation numbers, wherein the difference between the crystal melting start temperature and the end point temperature is in the range of 40 ° C to 5 ° C. The fractionated wax having a narrow melting temperature range may be in a liquid form depending on the type of the raw material wax, but most of the wax is a wax. The raw material containing the wax component is a low molecular weight polyethylene containing ethylene as a main component by-produced during the production of polyethylene (often copolymerized as propylene, butylene, etc. as the second component). 5-
1000 as main component, peak carbon number 20-20
0 low molecular weight polyethylene, and further low molecular weight polyethylene obtained by a polymerization method. In addition, various kinds of synthetic wax such as coal-based wax or its intermediate material, Fischer-Tropsch wax or its intermediate material or its intermediate material, petroleum-based wax or its intermediate material, that is, slack wax, scale wax, etc., and also natural wax etc. Waxes can be employed. The present invention is characterized in that a raw material wax is separated by a molecular weight without using a solvent, and a thermal property of the separated wax, that is, a crystal having a large heat of fusion and a sharp melting behavior is obtained. More specifically, a material obtained by distilling a lower molecular weight component from the raw material wax or dissolving the distillate, lowering the temperature of the melt, partially crystallizing the crystals, and sequentially performing an operation of separating the crystals. The object of the present invention is to obtain a target fractionated wax by adopting a method of obtaining a crystalline product. Here, an important point of the present invention is to obtain the desired fractionated wax by distillation from the raw material wax or by subsequent crystallization. It is an important point of the present invention that the raw material must be a distillate obtained by distillation of wax. The material obtained by melting the raw material wax itself and partially depositing crystals is creamy and has extremely poor distinctiveness. That is, clogging of the filter occurs early. If separation is forcibly performed by suction or the like, the crystal or the solidified amorphous portion will also pass through the filter, and the separation of the crystal and the uncrystallized melt will be incomplete.
As will be described later, it is not possible to separate the crystal, separate the remaining melt, and lower the temperature of the residual melt again, to obtain a crystal having a lower melting point and excellent thermal characteristics. The present inventor has previously invented and proposed (Japanese Patent Application No. 2-20 / 1990).
No. 7038) The wax fraction separated by the solvent extraction method was further subdivided by this liquid crystal precipitation.
The part in which crystals were partially deposited was creamy as a whole and was difficult to separate. The material obtained by distilling the raw material wax by distillation is cooled, and the temperature of the melt is reduced to partially crystallize the material. Although this phenomenon cannot be explained clearly in theory, it is an interesting and useful fact and one of the points that reached the present invention. In the present invention, the distillate is desirably made into a plurality by distilling, that is, a small amount is distilled by the first distilling distilling, and then the distilling residue is depressurized at a higher temperature or higher. Below, it is desirable that the higher molecular weight part is distilled off, and if necessary, the same treatment is repeated to sequentially distill out the high molecular weight side. A flowchart of the process is shown in FIG. The distillate obtained by distillation in this flowchart or the crystal obtained by melt liquid crystal separation from the distillate is the fractionated wax intended in the present invention. By increasing the number of distillations, preferably three or more, of the fractionated wax obtained by distillation, an excellent fractionated wax as the object of the present invention can be obtained. Further, from a plurality of distillates having different molecular weights, melt crystallization and crystallization are performed, and the thermal characteristics of the obtained crystals are determined by a single melt liquid crystal separation from a single distillate. A fractionated wax having better physical properties can be obtained from the obtained crystal. As described above, it is advantageous to obtain a plurality of distillates from the raw solid wax in order to obtain a fractionated wax having excellent thermal properties. Here, the distillation extraction operation can be performed by an existing device and method. For example, the first stage distillation is 5-8 mmHg, 260-290 ° C,
The second stage distillation is 0.1-0.01 mmHg, 250-270 ° C., the third stage distillation is 0.01 mmHg, 290 ° C., and the fourth stage distillation is 0.00.
Perform at 1mmHg, 290 ℃. At this time, it is preferable to use a thin-film distillation apparatus or the like for the second, third, and fourth stages of distillation in order to efficiently perform the distillation. Naturally, the distillation conditions will vary depending on the fractional wax to be obtained. For the purpose of obtaining the fractionated wax by separating the distillate of the first stage by liquid crystal precipitation, only one distillation distillation may be used. At this time, it is possible to increase the amount of the distillate by the number of repetitions of the liquid crystal deposition of the wax fraction and the range in which the physical properties of the fraction are allowed. Next, fusion liquid crystal deposition will be described. The distillate is heated at a predetermined temperature and melted. This is cooled to partially precipitate crystals. The mixture of the crystal and the non-crystal, ie, the melt, is separated by a filter. The separated first-stage crystals are those having a higher molecular weight in the distillate, that is, those having a higher melting point. Crystals separated from this mixture are fractionated waxes having a predetermined melting point and excellent thermal properties. On the other hand, the temperature of the melt that has passed through the uncrystallized filter is further lowered, and the low-molecular-weight side, ie, the second-stage crystal having a lower melting point, is separated from the previous crystal. . Here, the temperature of the uncrystallized melt is further lowered, and crystallization and separation are performed in the same manner to obtain a third-stage crystal. By such fusion liquid crystal deposition, repetition of each crystal, from the high molecular weight side, that is, from the high melting point,
A plurality of fractionated waxes having low molecular weights, that is, low melting points having different melting points are obtained. For example, by a five-step operation, a six-fractionated wax having a stepwise different melting point, including the melt passed through the last filter, can be obtained. The number of repetitions depends on how many fractionated waxes exhibiting the desired melting point are obtained from each distillate. In the crystallization from the melt, a method of continuously lowering the temperature and separating a precipitated crystal in a certain temperature range may be adopted. Furthermore, the rate of crystal precipitation at the time of melt liquid crystal deposition differs depending on the number of repetitions of the melt liquid crystal deposition and the manner of setting the melting point of the fractionated wax. For example, if the distillation distillate is divided into two equal parts by one crystallization, the crystallization yield may be 50%. Generally, the crystallization yield is less than 70%, preferably 50%
The thermal properties of the crystal obtained are better as follows. That is, the heat of fusion of the crystal becomes large, and the melting behavior becomes sharper. The crystallization of the melt can be carried out by a generally conceivable method. That is, the raw material wax is heated and melted in the vessel,
This may be cooled to a predetermined temperature and partially crystallized.
At this time, there may be some unmelted material that is not necessarily completely dissolved. The cooling rate may be any rate, but preferably slow cooling. When depositing crystals, a crystallization nucleus material, for example, an inorganic substance such as talc, a metal salt of a higher fatty acid, or a polymer such as polyethylene having a higher melting point than the raw material wax may be added. Further, stirring may be added. Separation of the precipitated crystal and the melt may be performed by a general filter. If pressure is applied by suction or pressing, separation can be made more quickly. Here, after the first stage, for example, the low molecular weight part of the first stage is distilled and distilled to have a peak carbon number of about 20 or less, the second stage, for example, the distillate from the second stage and thereafter, is the distillate of the distillate. Set the distillation conditions so that the carbon number peak is approximately 20 to 38,
A distillate having a carbon number distribution width of 5% or less in the high molecular weight part and the low molecular weight part, each of which accounts for 5% of the total amount, and a distillate whose carbon number is less than or equal to 20 is obtained by melting liquid crystal deposition and crystallizing. Melting peak temperature 55 ° C ~ 75 which is separated into liquid crystal
° C, melting energy 150-270J / g, melting temperature range 40 ° C-5
° C., and this is subjected to liquid crystal crystallization and crystallization separation, whereby a fractionated wax excellent in crystal melting behavior can be obtained. After distillation of the raw material containing the wax component, the residue after high vacuum distillation, the melting peak temperature 70 ° C
~ 100 ℃, melting energy 150 ~ 270J / g, melting temperature range 40 ℃
Fractionated waxes from solid waxes at 〜5 ° C. are also included in the present invention. That is, the fractionated wax has a melting peak temperature in the range of −35 ° C. to 100 ° C. by a differential scanning calorimeter, and has a crystal melting heat of 150 J / g to 300 J / g, preferably 170 J / g to 28 J.
It is 0 J / g. Further, the crystal melting temperature range is 40 ° C. to 5 ° C., preferably 30 ° C.
To 5 ° C, more preferably 20 ° C to 5 ° C. If the melting temperature range becomes larger than 40 ° C, the melting energy becomes 150J
If it is less than / g, the sensor function of the thermo sensor will be slowed down, sharpness will be lacking in the case of thermal paper, ribbon, etc.
In the case of a heat storage material, the heat storage and heat dissipation functions are insufficient, and in the case of a hot melt adhesive, the heat resistance is insufficient.

[Action]

The fractionated wax according to the present invention has a predetermined peak carbon number by fractional distillation, for example, from 5 to 70, from 10 to 20, or
Distillate in the most preferred range as a wax such as 20-38 or 32-60, and this as the desired fractionated wax,
Further, when this is subjected to melt liquid crystal deposition, jelly-like crystals are precipitated, so that it is easy to separate the crystals. If the temperature drop range is narrowed, sharper molecular weight fractionation is possible, so that wax having desired characteristics can be easily obtained.

【Example】

Hereinafter, the present invention will be described more specifically with reference to examples. Example 1 A low-molecular-weight polyethylene having a carbon number peak of 40, which is a by-product when polyethylene is produced by polymerizing ethylene mainly using a Ziegler catalyst, was used. This was distilled and distilled at 3 mmHg, 180-300 ° C. by simple distillation (sample A), and the distillation bottom (undistilled material) at this time was distilled and distilled at 0.2 mmHg, 260 ° C. using a film evaporator (sample). B) Further, at this time, the distillation bottom was distilled and distilled at 290 ° C. at 0.02 mmHg (sample C). Further, the distillation bottom after obtaining sample C was adjusted to 0.002 mmHg, 29
Distilled off at 0 ° C. (Sample D). Table 1 shows the physical properties of Samples A, B, C, and D obtained. The crystal melting temperature range decreases as the molecular weight increases. Example 2 The temperature of the sample A obtained in Example 1 was lowered to 20 ° C. to precipitate crystals, which were separated by suction at Nutsche at this temperature. The crystalline material on the Nutsche was strongly pressed with a flat plate from the upper portion so that the amorphous portion was sufficiently passed. The melting peak temperature of the obtained crystal (A-1) is
50 ° C, melting energy 208J / g, crystal melting temperature range 25 ° C
Met. Further, the temperature of the melt at another temperature of 20 ° C. was lowered to 10 ° C., and a crystal (A-2) was obtained by the same operation. This had a melting peak temperature of 37 ° C, a melting energy of 193 J / g, and a melting temperature range of 12 ° C. Example 3 Two kinds of crystals were obtained in the same manner as in Example 2 except that the sample B obtained in Example 1 was crystal-precipitated and the other temperatures were set at 61 ° C. and 57 ° C. The melting peak temperature, melting energy and melting temperature range of this product were (B-1) 72 ° C, 229 J / g, 14 ° C and (B-2) 66, respectively.
° C, 214 J / g, 15 ° C. Example 4 A fractionated wax was obtained from sample C obtained in Example 1 by the same operation as in Example 2 except that the temperature for crystal precipitation was set to 78 ° C. The melting peak temperature of this crystal (C-1) is
The melting temperature was 85 ° C, the melting energy was 230 J / g, and the crystal melting temperature range was 11 ° C. Example 5 A fractionated wax was obtained in the same manner as in Example 2, except that the sample D obtained in Example 1 was crystallized and the temperature was changed to 90 ° C. The melting peak temperature of this crystal (D-1) is 95
° C, melting energy 240 J / g, crystal melting temperature width 12 ° C. Example 6 A third-stage distillate (sample C ') was obtained from paraffin wax in the same manner as in Example 1. Its melting peak temperature is 72 ℃ and its melting energy is
The melting temperature range was 192 J / g, and the melting temperature range was 16 ° C. A crystal was obtained in the same manner as in Example 4, except that the temperature for crystal precipitation was set to 66 ° C. The resulting fractionated wax (C'-1) had a melting peak temperature of 79 ° C, a melting energy of 240 J / g, and a melting temperature range of 11 ° C.

【The invention's effect】

As described above, according to the method for producing a molecular weight fraction from a solid wax of the present invention, a fractionated wax having a narrow crystal melting temperature range can be obtained as various types of products having various melting peak temperatures over a wide melting point range, each of which is obtained by distillation and distillation. The relatively simple operation of melt liquid crystal deposition produces various high-quality waxes industrially. Therefore, those useful as raw materials for high-grade thermal paper (including thermal transfer ribbons), thermal sensors, and hot melt adhesives are easy to use. It is a manufacturing method that can be obtained.

[Brief description of the drawings]

FIG. 1 is a chart showing an example of a process for obtaining a fractionated wax having a narrow crystal melting temperature range according to the present invention.

Claims (6)

(57) [Claims] A raw material containing a wax component is removed by distillation from a low molecular weight portion as a fractionated distillate, and the peak carbon number of each distilled distillate is in the range of approximately 10 to 70, or is further reduced by distillation. By separating the product into a plurality of crystals having different carbon numbers by melt liquid crystal precipitation and crystal separation, a plurality of crystals each having a melting peak temperature in the range of approximately −35 ° C. to 100 ° C. are characterized. A method for producing a fractionated wax having a narrower crystal melting temperature range than a solid wax. 2. A distillate obtained by separating a raw material containing a wax component from a low molecular weight portion by distillation as a fractionated distillate, and distilling a distillate having a peak carbon number of about 10 to 20 from each distillate distillate. Further, it is separated into a plurality of crystals having different carbon numbers by melt liquid crystal precipitation and crystal separation, each having a melting peak temperature of −35 ° C. to 60 ° C. and a melting energy of 150 to 260 J /.
g, a method for producing a fractionated wax having a narrower crystal melting temperature range than solid wax, characterized by forming a plurality of crystals having a melting temperature range of 40 to 5 ° C. 3. The distillation distillate of each of the distillates has a peak carbon number of about 20 to 38 in the distillate distilled by high vacuum distillation, and the carbon number distribution width is a total amount in a high molecular weight part and a low molecular weight part. Or a distillate in which the carbon number occupying 5% is approximately 25 or less, or the distillate is further separated into a plurality of crystalline materials having different carbon numbers by melt liquid crystal deposition and crystallization, and each is melted. Peak temperature 40 ° C-90 ° C, melting energy 150-270J /
2. The method for producing a fractionated wax having a narrower crystal melting temperature range than a solid wax according to claim 1, wherein a plurality of crystals have a melting temperature range of 40 ° C to 5 ° C. 4. In each of the distillates, the peak carbon number distilled and distilled is approximately 32 to 60, and the carbon number distribution width occupies 5% of the total amount in the high molecular weight part and the low molecular weight part. Either a distillate having a carbon number of 25 or less, or a liquid crystal precipitation and separation into a plurality of crystals having different carbon numbers by crystal separation, each having a melting peak temperature of 65 ° C. to 95 ° C. 2. A method for producing a fractionated wax having a narrower crystal melting temperature range than the solid wax according to claim 1, wherein a plurality of crystals having a melting energy of 150 to 280 J / g and a melting temperature range of 40 to 5 ° C. are obtained. . 5. A raw material containing a wax component having 5 carbon atoms by-produced when producing polyethylene by the Ziegler method.
2. A low molecular weight polyethylene having a peak carbon number of 20 to 200 and having a molecular weight of from 1000 to 1000 as a main component.
A method for producing a fractionated wax having a narrower crystal melting temperature range than the solid wax described above. 6. After distillation of a raw material containing a wax component, a residue after distillate is removed by high-vacuum distillation is taken out, and the residue is subjected to liquid crystal precipitation and crystallization to a melting peak temperature of 70 ° C. to 10 ° C.
0 ° C, melting energy 150-270 J / g, melting temperature range 40 ° C-5
A method for producing a fractionated wax having a narrower crystal melting temperature range than a solid wax, wherein the fractionated wax is formed into a plurality of crystals at a temperature.