JPH09279332A - Refining method of organic compound monomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refining method of org. compd. monomers to efficiently remove impurities in the org. compd. monomers and to stabilize its vaporizing rate. SOLUTION: A vacuum treating device 1 is equipped with a vacuum chamber 2 in which a sealed state can be kept, and the chamber 2 is connected via the vacuum valve 6 to an evacuating system 7 such as an external vacuum pump not shown in the figure. The chamber 2 is surrounded with a heater 3 to heat the vacuum chamber 2. Plural containers 4 to house org. compd. monomers 5 such as MDI and MDA can be set in the vacuum chamber 2. In this constitution, the vacuum degree in the vacuum chamber 2 is controlled to high vacuum and the chamber 2 is heated by the heater 3. Monomers are heated to the temp. to control the vaporizing rate of the org. compd. monomers 5 to <=2×10<-8> g/cm<2> sec.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for purifying an organic compound monomer used in vapor deposition polymerization in which the organic compound monomer is evaporated to carry out polymerization.

[0002]

2. Description of the Related Art In recent years, a vapor deposition polymerization method has been proposed in which a polymer thin film is formed by evaporating an organic compound monomer of an organic compound in a vacuum and polymerizing it on a substrate.

FIG. 6 shows an example of a general vapor deposition polymerization apparatus. As shown in FIG. 6, this vapor deposition polymerization apparatus 1
01 has a processing chamber 102 capable of maintaining an airtight state, and this processing chamber 102 is connected to an external vacuum pump or other vacuum exhaust system (not shown). Then, the processing chamber 102
A substrate 103 on which a polymer thin film is to be formed is held downward by a substrate holder 104 in the upper part of the inside, and a heater 105 for heating the substrate 103 to a desired temperature is provided on the back side of the substrate holder 104. It is provided.

On the other hand, below the processing chamber 102, the substrate 10
An evaporation source for evaporating each of the organic compound monomers a and b is provided so as to counter 3. This evaporation source is provided with evaporation containers 106 and 107 made of, for example, glass, and in the vicinity of the evaporation containers 106 and 107,
Heaters 108 and 109 for heating and a temperature sensor 110,
111 is provided so that the evaporation rates of the organic compound monomers a and b are always kept constant.

A partition plate 112 is provided between the evaporation containers 106 and 107 to prevent the vapors of the organic compound monomers a and b from mixing with each other, and above the heaters 108 and 109 for heating. The shutter 113 is provided to prevent the vapor of the organic compound monomers a and b from entering.
Is provided.

Conventionally, as an example of forming a polymer thin film using such an apparatus, 4,4′-diphenylmethane diisocyanate (MDI) and 4,4′-diaminodiphenylmethane (MDA) were used to form a thin film on a substrate 103. A method of forming a polyurea film is known.

[0007]

However, such a conventional vapor deposition polymerization method has the following problems. That is, the above-mentioned MDI and MDA are heated to 70 ° C. and 100 ° C. in vacuum to be evaporated, and the substrate 10
When a polyurea film was to be formed on No. 3, if the vapor deposition was continued under the same temperature conditions, the thin film monomer was not formed between the film obtained in the initial stage of vapor deposition and the film obtained after a lapse of about 12 hours. Since the composition ratios are not the same, there is a problem that stable insulation properties, piezoelectric properties, and pyroelectric properties of the film cannot be obtained.

That is, in the past, as the monomer of the organic compound, a commercially available product was directly used for vapor deposition polymerization. Therefore, the impurities contained in the monomer are evaporated during the heating of the monomer, and the vapor due to the impurity is generated in the vicinity of the evaporation surface. Therefore, there is a problem in that the stable evaporation rate of the monomer cannot be obtained and the composition ratio of the monomer contained in the resultant polymer thin film is different.

In this case, if the vapor deposition is continuously carried out for about 24 hours, the impurities are almost released, so that the composition ratio of the monomers becomes almost constant. However, in this case, the removal efficiency of the impurities is poor, and therefore the vapor deposition polymerization is performed. There has been a problem that the process itself cannot be performed efficiently.

The present invention has been made in order to solve the problems of the conventional techniques, and purifies the organic compound monomer capable of efficiently removing the impurities contained in the organic compound monomer and stabilizing the deposition rate thereof. It is intended to provide a method.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, by heating an organic compound monomer at a predetermined temperature for a predetermined time in vacuum, vapor deposition polymerization We found that an organic compound monomer with a stable evaporation rate during heating was obtained,
The present invention has been completed.

That is, according to the first aspect of the present invention, the organic compound monomer is heated for a predetermined time in a vacuum at a temperature at which the evaporation rate is lower than the evaporation rate in vapor deposition polymerization to remove impurities in the monomer. Is characterized by.

Further, as in the invention described in claim 2, in the invention described in claim 1, the evaporation rate of the monomer is 2 × 1.
It is also effective to heat the monomer to a temperature of 0 ^-8 g / cm ² seconds or less. In this case, the lower limit of the evaporation rate of the monomer is not particularly limited, but the evaporation rate is 1 × 10
It is more effective to heat the monomer to a temperature higher than about ⁻¹⁰ g / cm ² · sec.

On the other hand, various kinds of organic compound monomers can be used. Particularly, as the organic compound monomer, 4,4'-diphenylmethane diisocyanate (MDI) is used as the organic compound monomer. Or it is more effective to use 4,4′-diaminodiphenylmethane (MDA) as in the invention of claim 4.

In the case of the invention described in claim 1, 3 or 4, the organic compound monomer (for example, MDI, MDA, etc.) is heated to remove impurities in the monomer. Since vapors due to impurities are not generated and the organic compound monomer is smoothly evaporated, a stable evaporation rate of the monomer can be obtained. As a result, the composition ratio of the monomers contained in the produced polymer thin film is kept constant.

In this case, the temperature at which the evaporation rate in vacuum is lower than the evaporation rate in the vapor deposition polymerization, in particular,
As in the described invention, the evaporation rate of the monomer is 2 × 10 ^-8
When the organic compound monomer is heated to a temperature of g / cm ² seconds or less, the organic compound monomer does not so much evaporate at the time of heating, and impurities mainly evaporate and are removed.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the method for purifying an organic compound monomer according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a schematic structure of an example of a vacuum processing apparatus to which the present invention is applied. As shown in FIG. 1, the vacuum processing apparatus 1 has a vacuum chamber 2 capable of maintaining an airtight state, and the vacuum chamber 2 includes an external vacuum pump (not shown) or other vacuum exhaust system via a vacuum valve 6. Connected to 7.

A heater 3 for heating the vacuum chamber 2 is wound around the vacuum chamber 2. In this case, as shown in FIG. 1, the heater 3 is wound around the entire upper, lower, left and right sides of the vacuum chamber 2 in order to perform uniform heating.

In the vacuum chamber 2, a plurality of containers 4 for containing the organic compound monomer 5 can be arranged. In the present embodiment, for example, three containers 4A, 4B,
4C is arranged, MDI, in each container 4A, 4B, 4C,
Organic compound monomers 5A, 5B, 5C such as MDA are stored. The container 4 may be either an evaporation container or a reagent bottle arranged in the vapor deposition polymerization apparatus.

When purifying an organic compound monomer using the vacuum processing apparatus 1 having such a configuration, a container 4 in which the organic compound monomer 5 is injected is placed inside the vacuum tank 2 and the vacuum of the vacuum tank 2 is set. High vacuum (1 × 10 ^-3 Pa)
And the heater 3 heats the vacuum chamber 2 for a predetermined time.

In the present embodiment, since the organic compound monomer 5 is heated in vacuum to remove impurities,
Since vapor due to impurities is not generated during the heating of the monomer in the vapor deposition polymerization and the evaporation is smoothly performed, a stable evaporation rate of the organic compound monomer 5 can be obtained. As a result, the composition ratio of the monomers in the generated polymer thin film can be kept constant, and the insulating properties, piezoelectric properties, and pyroelectric properties can be stabilized.

In this case, the organic compound monomer is heated to a temperature at which the evaporation rate of the monomer is 2 × 10 ⁻⁸ g / cm ² seconds or less so that the evaporation rate in vacuum becomes lower than the evaporation rate in vapor deposition polymerization. By doing so, the organic compound monomer hardly evaporates at the time of heating, and the impurities mainly evaporate and are removed, so that the impurities can be efficiently removed.

Further, according to the present embodiment, since a plurality of containers 4 can be accommodated in the vacuum chamber 2, the composition ratio of the monomers is stabilized by evaporating for a long time in the vapor deposition polymerization apparatus. The use efficiency of the vapor deposition polymerization apparatus can be improved as compared with the conventional method.

[0025]

EXAMPLES Examples of the method for purifying an organic compound monomer according to the present invention will be described in detail below. As shown in FIG.
Container 4 into which MDI was injected as organic compound monomer 5A
A is placed inside the vacuum chamber 2 and placed in a high vacuum (1 × 10 ⁻³ P
In a), it was heated to 47 ° C. and left for 60 hours to remove impurities.

Further, MD is used as the organic compound monomer 5B.
The container 4B in which A was injected was placed inside the vacuum chamber 2 and heated to 60 ° C. in a high vacuum (1 × 10 ⁻³ Pa),
It was left for a period of time to remove impurities.

Then, these containers 4A and 4B were mounted on a general vapor deposition polymerization apparatus, and after evacuation to a predetermined vacuum degree, the respective containers 4A and 4B were heated to 70 ° C. and 100 ° C.
Then, the organic compound monomers 5A and 5B were evaporated to form a polyurea film on the substrate.

When the polyurea film was continuously vapor-deposited by such a method, the relative permittivity of the polyurea film formed immediately after the vapor deposition was 4.3. Furthermore, the relative permittivity of the polyurea film 1 hour after the start of vapor deposition becomes 4.0, and thereafter,
Relative permittivity of 4.0 ± 0.0 for 30 hours continuously
A polyurea film of No. 5 was stably obtained.

Next, the operation of this embodiment will be described in detail with reference to FIGS. FIG. 2 is a graph showing changes with time of typical peaks of mass spectra obtained when MDI, which is a commercially available organic compound monomer, is heated to 47 ° C. in vacuum.

Since MDI has a molecular weight of 250, the curve A in which m / e (m is the mass of ions, e is the charge of ions) = 250 represents MDI, and is added to commercially available MDI. Since the molecular weight of 4-methyl-2,6-ditertiary butylphenol used is 205, the curve B with m / e = 205 is due to this.

As shown in FIG. 2, the MDI is vacuumed at 47.
Curve B showing peak intensity of impurity components when heated to ℃
Is decreased with time, and it is understood that the impurity component contained in the monomer is almost eliminated after about 60 hours.

On the other hand, FIG. 3 is a graph showing changes with time of typical peaks of mass spectra obtained when MDA, which is a commercially available organic compound monomer, is heated to 60 ° C. in vacuum.

Here, since MDA has a molecular weight of 198, curve C with m / e = 198 represents MDA, while curve D with m / e = 93 is contained as an impurity in commercially available MDA. It is presumed to be due to aniline.

As shown in FIG. 3, when the MDA monomer is heated to 60 ° C. in vacuum, the curve D showing the peak intensity of the impurity component decreases with time, and after about 10 hours, the impurity component contained in the monomer is generally reduced. It is understood that it will come out.

FIG. 4 is a graph showing the relationship between the evaporation temperature of MDI and the evaporation rate. As can be seen from FIG.
At 47 ° C., which is the evaporation temperature of MDI in the examples, the evaporation amount of MDI as a monomer is small, which is one digit or more smaller than the evaporation amount at 70 ° C. which is the evaporation temperature during vapor deposition polymerization. Therefore, according to the method of the present embodiment,
It is possible to efficiently remove the impurity gas from the MDA monomer.

FIG. 5 is a graph showing the relationship between MDA evaporation temperature and evaporation rate. As can be seen from FIG.
At 60 ° C., which is the evaporation temperature of MDI in the examples, the evaporation amount of MDI as a monomer is extremely small, which is a value almost two orders of magnitude smaller than the evaporation amount at 100 ° C. which is the evaporation temperature during vapor deposition polymerization. Therefore, according to the method of the present embodiment, it is possible to remove the impurity gas efficiently even with respect to MDI.

[0037]

As described above, according to the present invention, vapors due to impurities are not generated during heating of monomers in vapor deposition polymerization, and the vaporization is performed smoothly. It can be removed well and the deposition rate can be stabilized. As a result, the composition ratio of the monomers in the polymer thin film formed by vapor deposition polymerization can be kept constant, and the insulating properties, piezoelectric properties, and pyroelectric properties can be stabilized.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a vacuum processing apparatus to which the present invention is applied.

FIG. 2 is a graph showing changes with time of representative peaks of mass spectra obtained when MDI, which is a commercially available monomer, is heated to 47 ° C. in vacuum.

FIG. 3 is a graph showing changes with time of typical peaks of mass spectra obtained when MDA, which is a commercially available monomer, is heated to 60 ° C. in vacuum.

FIG. 4 is a graph showing the relationship between MDI evaporation temperature and evaporation rate.

FIG. 5 is a graph showing the relationship between MDA evaporation temperature and evaporation rate.

FIG. 6 is a schematic configuration diagram showing an example of a general vapor deposition polymerization apparatus.

[Explanation of symbols]

1 ... Vacuum processing device, 2 ... Vacuum tank, 3 ... Heater, 4 (4
A, 4B, 4C) ... Container, 5 (5A, 5B, 5C) ... Organic compound monomer, 6 ... Vacuum valve, 7 ... Vacuum exhaust system

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08G 85/00 NUY C08G 85/00 NUY C23C 14/24 C23C 14/24 E

Claims (4)

[Claims] 1. An organic compound monomer, which is characterized in that an organic compound monomer is heated for a predetermined period of time in vacuum at a temperature at which the evaporation rate is lower than the evaporation rate in vapor deposition polymerization to remove impurities in the monomer. Purification method. 2. The evaporation rate of the monomer is 2.times.10.sup.- ⁸ g / cm.sup.2.
^The method for purifying an organic compound monomer according to claim 1, wherein the monomer is heated to a temperature of ² seconds or less. 3. The method for purifying an organic compound monomer according to claim 1, wherein the organic compound monomer is 4,4′-diphenylmethane diisocyanate (MDI). 4. The method for purifying an organic compound monomer according to claim 1, wherein the organic compound monomer is 4,4′-diaminodiphenylmethane (MDA).