JPH0747663B2 - Foam pellets of chlorinated polyolefin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention can be used by dissolving toluene, xylene alone, or toluene or xylene and another organic solvent (these are abbreviated as a use solvent as described above). The present invention relates to a foamed pellet of chlorinated polyolefin containing or not containing a foaming agent, which is a raw material to be supplied.

[Conventional technology]

Conventional chlorinated polyolefin has strong adhesiveness,
It is usually made into pellets and dissolved in an aromatic hydrocarbon solvent such as toluene or xylene alone or in a mixed solvent with other organic solvents such as ketones and esters (hereinafter simply referred to as mixed solvent) for adhesives and inks. It is widely used for paints, coatings, and as a primer for polypropylene moldings.

[Problems to be Solved by the Invention]

When the chlorinated polyolefin pellets are dissolved in the solvent used, for example, toluene, xylene or other mixed solvent using a dissolution tank equipped with a stirrer, the conventional chlorinated polyolefin pellets are precipitated in the dissolution tank and only the surface is dissolved by the solvent. Then, the polyolefin pellets were partially dissolved and bonded together to form a soft rice cake-like, sticking to the bottom of the dissolution tank, the effect of the stirrer was not exerted, and it took a long time and significant power to dissolve, In addition, there was a problem that it was difficult to dissolve it uniformly.

In order to solve these problems, the present inventors have found that when chlorinated polyolefin pellets are dissolved in a solvent used, they do not precipitate in a dissolution tank and are floated so that they are easily dissolved by stirring. By producing a foamed pellet of modified polyolefin and by using it, the foamed pellet can be suspended in the solvent used, and the stirring becomes smooth,
The present invention has been completed by confirming that the foamed pellets can be easily dissolved in a solvent, and the present invention is to be dissolved in a solvent to be used. It is an object of the present invention to provide a foamed pellet of chlorinated polyolefin.

[Means for Solving the Problems]

The present invention is to inject an inert gas, carbon dioxide gas or air into a solid chlorinated polyolefin obtained by removing the solvent used in the production thereof from a solution chlorinated polyolefin, that is, the above-mentioned production solvent such as a carbon tetrachloride solvent. Alternatively, the production solvent remaining in the solid chlorinated polyolefin is heated under reduced pressure to separate and foam, or the production solvent and / or the production solvent is added to the produced chlorinated polyolefin and heated under reduced pressure. The present invention relates to a foamed pellet of chlorinated polyolefin which is released and foamed.

Injecting an inert gas, carbon dioxide gas or air of the present invention,
Alternatively, the production solvent remaining in the solid chlorinated polyolefin is heated under reduced pressure to separate and foam, or the production solvent and / or the production solvent is added to the produced chlorinated polyolefin and heated under reduced pressure. The foamed pellet of chlorinated polyolefin that has been separated and foamed has an apparent specific gravity (residual gas in the present invention, such that it floats in the solvent used,
The specific gravity of the foamed pellet partially containing the production solvent and / or the used solvent is defined as the apparent specific gravity. ) And is dissolved in the solvent used, it is easily stirred and dissolved by the stirrer in the dissolution tank because it floats in the solvent used.

As the chlorinated polyolefin of the present invention, chlorinated polyethylene and chlorinated polypropylene are usually used, but the chlorinated polyolefin is not limited thereto.

Table 1 shows the main solvents used as the solvent for the foamed pellets of chlorinated polyolefin together with the specific gravity. The specific gravity is indicated by the value measured at 20 ° C.

Of the solvents in Table 1, toluene and xylene are used alone as described above, but other solvents are used as a mixed solvent by mixing with toluene or xylene.

When the foamed pellet of chlorinated polypropylene is dissolved in the solvent used, there is a relationship between the apparent specific gravity of the foamed pellet of chlorinated polypropylene and the true specific gravity of the solvent.

The true specific gravity of chlorinated polypropylene depends on the chlorine content and the amount of manufacturing solvent remaining in the chlorinated polypropylene, but 1.
It is about 08 to 1.17, and the average is about 1.1.

In order to float the chlorinated polypropylene foam pellets in the solvent used, it is necessary to make the volume expansion coefficient less than approximately as described below, and the gas, the production solvent and / or the used solvent are partially contained. It is necessary to reduce the apparent specific gravity of the residual chlorinated polypropylene foam pellets to at least less than the true specific gravity of the solvent used.

For example, in order for the chlorinated polypropylene foam pellets to float in toluene, which is the solvent used in Table 1, Therefore, the foaming rate must be 26.9% or more.

Similarly, to float in xylene solvent, Therefore, the foaming rate must be 27.9% or more.

Other mixed solvents also differ depending on the mixing ratio of toluene or xylene and other organic solvent, but since the specific gravity of each is determined by the mixing ratio, the same chlorinated polypropylene as in the case of toluene and xylene. The rate of foaming that causes the foam pellets to be suspended is determined.

That is, in order to suspend the foaming pellets of chlorinated polypropylene in which nitrogen gas, carbon dioxide gas, air or the manufacturing solvent and / or the used solvent remain in the used solvent such as toluene, xylene and mixed solvent, at least the above foaming ratio or more is required. There is a need to.

Nitrogen gas is mainly used as the inert gas used when the solid chlorinated polypropylene is heated and press-fitted. Instead of nitrogen gas, carbon dioxide gas or a substance that generates carbon dioxide gas can also be used.

〔Example〕

 The present invention will now be described with reference to the drawings.

FIG. 1 shows a cylinder type extruder for producing a foamed pellet of chlorinated polypropylene by releasing a carbon tetrachloride solvent from a solution chlorinated polypropylene having an opening at the top under a high temperature and reduced pressure and then injecting nitrogen gas at a high temperature. A schematic cross-sectional view is shown, in which carbon tetrachloride is released from the carbon tetrachloride solution of chlorinated polypropylene under heating and reduced pressure by using the apparatus shown in FIG. A chlorinated polypropylene foam pellet is obtained by cutting into pieces. The measurement results are shown in Table 2. As a result of measurement under the conditions shown in Table 2, the nitrogen content of the foamed pellets of chlorinated polypropylene was 34.02% for No.2,4, 33.03% for No.3 and No.7.
It was 38.15%. In Table 2, ⊚ indicates that the foam pellet floats in the toluene solvent, Δ indicates that it floats or sinks, and x indicates that it sinks as a result of the No. 1 blank test.

FIG. 2 shows the melting temperature and the melting time at various melting temperatures when the foamed pellets of the nitrogen gas-containing chlorinated polypropylene of the present invention, the conventional chlorinated polypropylene pellets and the air-containing foamed pellets described below are dissolved in a toluene solvent. The relationship with It can be seen that there is a marked difference in the dissolution time when the dissolution temperature is around 30 ° C, which is the usual condition.

Furthermore, in the case of foamed pellets of aerated chlorinated polypropylene, the chlorinated polypropylene solution dissolved in carbon tetrachloride, which is the manufacturing solvent, is dried by sucking carbon tetrachloride with a drum dryer and collecting it to remove the solvent. It is possible to produce a foamed pellet by bundling it into a tape and allowing it to contain air.

An example of the air content of foam pellets in this case is 42.66%
It was. Therefore, foamed pellets floating in toluene, which is used as a solvent, are produced, as shown in Fig. 2 (6),
It can be seen that it exhibits excellent solubility as shown by the curve (6) '.

Further, even when the cylinder type extruder shown in FIG. 1 is used or the drum dryer method is used, when carbon tetrachloride is released from the chlorinated polypropylene solution, carbon tetrachloride is left behind or carbon tetrachloride is left. A solvent such as toluene is added to the remaining solid chlorinated polypropylene to make it contained in the chlorinated polypropylene under pressure, and then the solvent is removed to produce a foamed pellet of chlorinated polypropylene in the same manner as described above. It is possible.

The foam pellets of the present invention are not limited to the production according to the above embodiment alone.

〔The invention's effect〕

As shown in FIG. 2, a polypropylene foam pellet containing inert gas, carbon dioxide gas or air produced according to the present invention floats in a solvent such as toluene, xylene or other mixed solvent, and the conventional chlorine The dissolution time at 30-40 ° C is significantly faster than that of the modified polyolefin particles, and the difference in the dissolution time becomes larger as the temperature becomes lower. In contrast, conventional chlorinated polyolefins take a significantly longer time to dissolve and thus require more power.

Further, the foamed pellets of chlorinated polyolefin of the present invention are used in the production of chlorinated polyolefin, for example, by dissolving carbon tetrachloride to remove the solid chlorinated polyolefin, and the solid chlorinated polyolefin is linked to the production process to prepare an inert gas, carbon dioxide gas, air and Has the advantage that the object of the present invention can be achieved by adding carbon tetrachloride as a production solvent and / or toluene as a solvent to be used to remove these solvents under heating and reduced pressure, or partially including them.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an extrusion-type manufacturing apparatus for solidifying a chlorinated polyolefin dissolved in a carbon tetrachloride solution of the present invention, and injecting an inert gas under pressure to cut the chlorinated polyolefin to produce a foamed pellet of chlorinated polyolefin. FIG. 2 is a diagram showing the relationship between the dissolution time and the dissolution temperature of the chlorinated polyolefin of the present invention in the foamed pellet of toluene. 1. Charging port for chlorinated polypyrrolene carbon tetrachloride solution 2. Vacuum suction port 3. Nitrogen cylinder 4. Strand cutter device 5. Dissolution time of chlorinated polypropylene foam pellets containing nitrogen gas in toluene solvent, temperature curve 6,6 ′. Dissolving time and temperature curve of chlorinated polypropylene foam pellets containing air 7. Dissolving time and temperature curve of conventional chlorinated polypropylene

Claims (2)

[Claims] 1. A solid chlorinated polyolefin obtained by releasing a solvent (hereinafter referred to as a production solvent) used at the time of its production from a solution chlorinated polyolefin, by injecting or containing an inert gas, carbon dioxide gas or air, or Alternatively, the production solvent remaining in the solid chlorinated polyolefin is heated and released under reduced pressure to cause foaming, or the produced chlorinated polyolefin is a soluble solvent at the time of use (hereinafter referred to as a used solvent) and / or a production solvent. A foamed pellet of chlorinated polyolefin in which is added and heated under reduced pressure to release the foam. 2. Solid chlorinated polyolefin with nitrogen gas,
Carbon dioxide gas or air is injected under pressure, or the production solvent remaining in the solid chlorinated polyolefin is heated and foamed under reduced pressure, or the produced solvent is added to the produced chlorinated polyolefin and the production solvent is added under reduced pressure. 2. The chlorinated polyolefin of claim 1, wherein the apparent specific gravity of the foamed pellet of the chlorinated polyolefin produced by foaming is reduced to less than the true specific gravity of the solvent used for the foamed pellet of the chlorinated polyolefin. Foam pellets.