JPS5825340B2 - Method for producing chlorinated vinyl chloride resin foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a chlorinated vinyl chloride resin foam.

Chlorinated vinyl chloride resin foam is characterized by better heat resistance than vinyl chloride resin foam.

That is, the chlorinated vinyl chloride resin foam has a very small shrinkage rate at high temperatures and can withstand higher temperatures, so it can be used for hot water piping, steam piping, etc., and for purposes of heat retention.

It also has excellent flame retardancy, making it suitable for use as a building material.

Furthermore, since it has excellent mechanical strength and electrical insulation, it can be used for electrical parts, and because it has good chemical resistance, it can be used for equipment in the chemical industry.

Chlorinated vinyl chloride resin foams have a number of excellent properties as described above, and are therefore expected to be applied to a variety of uses.

However, no satisfactory method for producing chlorinated vinyl chloride resin foams has been known so far.

For example, Japanese Patent Publication No. 43-12009 teaches the use of halogenated hydrocarbons as blowing agents.

However, halogenated hydrocarbons are toxic and volatile compounds that must be handled with care, and their use therefore requires special safety equipment.

Additionally, halogenated hydrocarbons impair the thermal stability of the resin, often resulting in colored and poor quality foams.

Therefore, the method taught in this publication was not satisfactory.

On the other hand, as a method for manufacturing vinyl chloride resin foam, a method of foaming using an organic solvent that can be gasified by heating has been known, but since ordinary vinyl chloride resin has poor solvent retention, It was not possible to produce a satisfactory foam using this method.

The inventors found that a vinyl chloride resin that is post-chlorinated to have a chlorine content of 60% by weight or more has good solvent retention properties, and that by incorporating a solvent into it and foaming it,
This invention was completed by discovering that it is possible to produce a uniformly fine foam.

That is, in the present invention, a hydrocarbon solvent, an ether solvent, or a ketone solvent having a boiling point of 150°C to 160°C is added to a chlorinated vinyl chloride resin having a chlorine content of 60 to 75% by weight. , and 1 to 50 parts by weight of one or more solvents selected from ester solvents, and foaming by heating. be.

The chlorinated vinyl chloride resin used in this invention refers to a chlorinated vinyl chloride resin.

The vinyl chloride resin mentioned here includes vinyl chloride homopolymers and copolymers.

The copolymer is a copolymer obtained by copolymerizing 90% by weight or more of vinyl chloride with one or more monomers that can be copolymerized with vinyl chloride, or a graft copolymer. Contains polymers.

Examples of monomers copolymerizable with vinyl chloride include vinyl or vinylidene monomers such as ethylene, propylene, vinyl acetate, styrene, acrylonitrile, and vinylidene chloride.

These vinyl chloride resins can be chlorinated by a known chlorination method.

That is, in a closed container equipped with a stirring device, vinyl chloride resin is suspended in water, oxygen in the container is removed, and then suspension chlorination is carried out using chlorine under ultraviolet irradiation, followed by chloroform or tetrachloride in water. Solution chlorination is performed by adding a halogenated organic compound such as carbon and chlorinating the vinyl chloride resin in the solution, or by fluidizing the vinyl chloride resin powder with chlorine or a mixed gas of chlorine and nitrogen. Either gas phase chlorination or chlorination under ultraviolet irradiation can be used.

The chlorinated vinyl chloride resin thus obtained is preferably in the form of a white powder with an average particle size of 100 μm and an average degree of polymerization of 100 to 2,000.

If the average degree of polymerization is less than 100, the physical properties are poor;
The above materials have too high melt viscosity and are difficult to foam.

Most preferred are resins with an average degree of polymerization of 300 to 1,000.

The chlorine content of the chlorinated vinyl chloride resin used in this invention must be at least 60%.

If such a resin is used, a foam having uniform and fine cells can be obtained.

Generally, as the chlorine content increases, heat resistance improves and foaming properties become better, but if the chlorine content becomes too high, heating and melting becomes difficult and chlorination takes a long time, making it uneconomical.

Therefore, in this invention, a resin having a chlorine content of 75% by weight or less is used.

Among these, resins having a chlorine content of 65 to 72% by weight are preferred.

Among the solvents with a boiling point of -50'C to 160°C used as a foaming agent in this invention, examples of hydrocarbon solvents include propane, butane, pentane, hexane, heptane,
octane, nonane and their isomers, propylene,
Butene, pentene, hexeno, octene, nonene and their isomers, fluoracien, phtadiene, pentadiene, hexadiene, heptadiene, ofcudiene, nonadiene and their isomers, cyclobutane, methylcyclopropane, ethylcyclopropane, dimethylcyclopropane, isopropyl Cyclopropane, trimethylcyclopropane, methylethylcyclopropane, tetramethylcyclopropane, diethylcyclopropane, dimethylethylcyclopropane, methylpropylcyclo7'
D 7 <F, ethyl-n-butylcyclopropane, cyclobutane, methylcyclobutane, ethylcyclobutane, dimethylcyclobutane, methylethylcyclobutane, dimethyldiethylcyclobutane, isopropylcyclophtane, cyclopenkune, methylcyclopenkune, ethylcyclopenkune, Propylcyclopenkune, Isopropylcyclopenkun, Methylethylcyclopenkun,
Dimethylcyclopenkune, diethylcyclopenkune, cyclohexane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, methylethylcyclohexane, cyclohebutane, methylcyclohebutane, cyclooctane, benzene, toluene, xylene, petroleum ether, petroleum benzine, ligroin, Includes petroleum spirits, etc.

Examples of ether solvents include methyl-n-propyl ether, methyl-n-butyl ether, methyl tert-butyl ether, ethyl-70-butyl ether, and methyl-n-butyl ether.
amyl ether, methylisoamyl ether, ethyl-
n-butyl ether, ethyl isobutyl ether, ethyl secondary butyl ether, ethyl tertiary butyl ether, di-n-propyl ether, diisopropyl ether, methyl-n-hexyl ether, ethyl-n-amyl ether, ethyl tertiary amyl ether , ethyl neopentyl ether, n-propyl isobutyl ether, isopropyl-n-butyl ether, n-propyl tertiary butyl ether, isopropyl tertiary butyl ether,
Ethyl-n-hexyl ether, di-n-butyl ether, n-butyl tert-butyl ether, ethyl-α-
Methyl hexyl ether, diisoamyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol methyl ethyl ether, ethylene glycol methyl-n-fluor ether, ethylene glycol diethyl ether, RIJ serine -1-
Methyl ether, chrycerin-2-methyl ether, glycerin-1-propyl ether, chrycerin-1,2
-dimethyl ether, glycerin-1,3-dimethyl ether, chrycerin-1,3-diethyl ether, chrycerin-1-ethyl-2-propyl ether, glycerin trimethyl ether, glycerin triethyl ether, glycerin-1,3-dimethyl-2-propyl Ether, glycerin-1-ethyl-2-methyl-3-propyl ether, chrycerin-1,3-diethyl-2-propyl ether, ethynyl butyl ether, 2-methoxy-2-butene, 2-methoxy-1,3-butadiene , methyl mecryl ether, 2-ethoxypropene, vinyl allyl ether, ethyl crotyl ether, 2-ethoxy-1-butene, 3-ethoxy-nibutene, 2-ethoxy-1,3-butadiene, ■, 3-dimethoxy-2-
Butene, trans-1,2-jethoxyethylene, 6-
Medoxy 1-hexene, 2-methoxy-1-hexene, 3-methoxy-3-hexene, allyl methallyl ether, isoprobyl mecryl ether, 7-medoxy 1
-Heptene, diethyl ether, tertiary butyl methallyl ether, trans-1-methoxy-2-octene, methylpropargyl ether, 4-methoxy-1-butyne, 4-methoxy-2-butyne, 4-ethoxy-1-butyne , ■-methoxy 2-octyne, ethylene oxide,
1゜2-Epoxypropane, 1,2-dimethylethylene oxide, trans-2,3-epoxypenkune, cis-2,3-epoxypenkune, 2-methyl-2,3-epoxybutane, ■, 2-epoxy 3-oxy-n-hexane, 1,2-epoxydecane, ■, 1-dineopentyl ethylene oxide, 1,4-dioxane, trioxane, furan, 2-methylfuran, tetrahydrofuran, diethylacecour, diglycidyl ether, diglycidyl Includes acecool, methicool, etc.

Ketone solvents include acetone, diethyl ketone, di-n-propyl ketone, diisopropyl ketone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl butyl ketone, ethyl propyl ketone, methyl isobutyl ketone, methyl secondary butyl ketone, methyl Tertiary butyl ketone, methyl-n-amyl ketone, methyl secondary amyl ketone, ethyl butyl ketone, mesityl oxide, oxyacetone, diacetyl, acetylacetone, 2,6-hebutanedione, 2°7-octanedione, methyl vinyl ketone, Methyl isopropenyl ketone, ethyl vinyl ketone, propyl vinyl ketone, isobutyl vinyl ketone, methyl allyl ketone, ethyl allyl ketone, propyl allyl ketone, methyl propenyl ketone, ethyl propenyl ketone, isobutylidene acetone, allyl acetone, 2-methyl-2 -hebuten-6-one, diallylacetone, methyl ethynyl ketone, n-propylethynyl ketone, 3-pentyne-2-
on, 3-octyn-2-one, 3-nonyn-2-one, acetylethylcarbinol, acetyldimethylrubisol, 3-he-1-/-4-one, butyroin, pivaloin, cabroin, 2-acetyl Ethyl alcohol, 3-methyl-2-pentanol-4-one, acetylpropionyl, acetylbutyryl, acetylisobutyryl, acetylisovaleryl, dipropionyl, diisobutyryl, cicabroyl, caproylacetone, 6-
Methyl-2,5-hebutanedione, acetylethylene,
Includes α-dimethylacetonylacetone, diacetylpropane, diacetylbutane, etc.

In addition, ester solvents include methyl formate, ethyl formate, propyl formate, isopropyl formate, n-butyl formate, isobutyl formate, amyl formate, methyl acetate, ethyl acetate, n-propyl acetate, acetic acid. Isopropyl, n-butyl acetate, isobutyl acetate, secondary butyl acetate, n-amyl acetate, isoamyl acetate, methylisoamyl acetate, vinyl acetate, sec-hexyl acetate, methyl propionate, ethyl propionate, n-butyl propionate, Includes isobutyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, methyl methacrylate, methyl lactate, ethyl lactate, and the like.

These solvents may be used alone or as a mixture of two or more.

These solvents act not only as foaming agents but also as softeners.

Solvents with boiling points lower than 150°C, such as methane and ethane, have poor affinity with chlorinated polyvinyl chloride resins and therefore do not act as softeners.

Therefore, when molding a resin foam, it is necessary to raise the temperature in order to obtain an appropriate viscosity, which results in high pressure.

Also, these molecules are small.

Therefore, the gas holding power of the resin is small, and there is a drawback that gas escape during molding is significant.

On the other hand, a solvent with a boiling point higher than 160° C. has a boiling point close to the molding temperature, and therefore has the disadvantage that even if an appropriate viscosity is obtained, an appropriate gas pressure cannot be obtained.

The amount of foaming agent (ie, solvent) used is required to be from 1 to 50 parts by weight based on 100 parts by weight of the chlorinated vinyl chloride resin.

The reason for this is that if the foaming agent is less than 1 part by weight, the ability to form bubbles will be insufficient, while if it is more than 50 parts by weight, it will be difficult for the foaming agent to completely vaporize, and the amount remaining in the resin foam will decrease. This is because the amount increases and there is a risk that heat resistance will be impaired.

Among these, the preferred amount used is 5 to 20 parts by weight.

In the method of this invention, various additives can be used in addition to the above-mentioned solvents.

For example, known nucleating agents can be used to generate uniform bubbles.

Known nucleating agents include fine powders such as calcium carbonate, calcium sulfate, silica, and calcined clay.

The nucleating agent is preferably used in an amount of 5 to 50 parts by weight, based on 100 parts by weight of the chlorinated vinyl chloride resin.
More preferably, 0 to 20 parts by weight are used.

The reason for this is that if the amount of the nucleating agent used is too large, the resulting resin foam will become brittle, while if it is too small, sufficient effects will not be obtained.

In the method of the present invention, when the resin mixture is heated and molten to foam by pressing, it is generally not necessary to use stabilizers, lubricants, etc.

The reason is that the solvent used as a foaming agent in this invention is
This is because a white resin foam can be obtained without using a stabilizer since the thermal stability of the resin is not impaired.

Since stabilizers are generally expensive, eliminating the use of stabilizers significantly reduces the cost of the resin foam.

On the other hand, if a known halogenated hydrocarbon is used as a blowing agent, the resin will turn yellow unless a stabilizer is used.

However, even with the method of this invention, if the resin mixture is foamed using an extruder, the heating time will be longer.
It is desirable to use stabilizers.

As the stabilizer and lubricant, known ones such as dibasic lead sulfate, dibutyltin laurate, etc. can be used.

Furthermore, pigments, glass fibers, and resins other than chlorinated vinyl chloride resins, such as methyl methacrylate-butadiene-styrene copolymer, etc., can be added.

If these are used in large quantities, foaming of the resin will be inhibited, so it is preferable to use 5 to 30 parts by weight per 100 parts by weight of the chlorinated vinyl chloride resin.

Various known methods can be used to incorporate the solvent used as a foaming agent into the chlorinated vinyl chloride resin powder.

The first method is to mix a foaming agent with chlorinated vinyl chloride resin powder or pellets at room temperature and pressure, and then place the mixture in a sealed container and leave it at room temperature to impregnate it with the foaming agent. .

The second method is to put the powder or mixture into an extruder, heat and knead it, and press a foaming agent in the middle of the process to impregnate the foaming agent.

The third method is to mix a foaming agent into powder or pellets of chlorinated vinyl chloride resin at room temperature, place the mixture in a sealed container, heat it, and leave it under heating and pressure to incorporate the foaming agent. It is.

Of these, the first method is the most economically advantageous.

The foaming agent used in the present invention may be incorporated into the resin by any of the first to third methods described above.

In order to incorporate a foaming agent into the pellets of chlorinated vinyl chloride resin, the pellets may be heated together with the foaming agent in a closed container.

In the method of this invention, in order to foam the chlorinated vinyl chloride resin containing the solvent used as a foaming agent, for example, the resin containing the foaming agent is placed in a closed mold, and the chlorinated vinyl chloride resin containing the foaming agent is placed in a closed mold. Heat and pressure are applied for several minutes to the melting temperature of the resin or the temperature at which resin particles begin to coalesce, for example 160 to 210°C.

Applying pressure promotes melting of the resin particles. Thereafter, when the mold is gradually or suddenly opened, a resin foam having uniform and fine cells is obtained.

Alternatively, the foam can be manufactured while continuously extruding the resin in an extruder.

In this case, as an extruder, the area around the hopper was kept at a low temperature, preferably below 50°C, the cylinder tip was kept at a higher temperature than the area around the hopper, preferably 100 to 150°C, and the mold temperature was adjusted to 130 to 200°C. If this method is used, it is possible to continuously produce a resin foam having uniform, fine cells.

At this time, the solvent used as a foaming agent may be included in the chlorinated vinyl chloride resin in advance, but it may also be press-fitted at any position between the hopper outlet of the extruder and the cylinder tip. .

The chlorinated vinyl chloride resin foam obtained by the method of the present invention has excellent heat resistance, flame retardancy, electrical insulation, and the like.

Further, according to the method of the present invention, since the foaming agent has low toxicity, the work can be carried out safely, and no special safety equipment is required for the foaming work.

Further, according to the method of the present invention, since the blowing agent does not inhibit the thermal stability of the resin, it is easy to obtain a high-quality foam that does not develop color.

Therefore, according to the method of this invention, a high quality chlorinated vinyl chloride resin foam can be produced economically.

EXAMPLES Hereinafter, the method of the present invention will be explained in detail with reference to Examples, and the effects of the present invention will be clarified with reference to Comparative Examples.

In addition, in the examples, the term "parts" simply means parts by weight.

Example 1 (a) 45 kg of polyvinyl chloride powder with an average particle size of 200 μm and an average degree of polymerization of 1 ooo, and 180 kg of pure water,
The mixture was placed in a jacketed glass-lined reaction tank having an internal volume of 30 (l) and equipped with an ultraviolet ray generator and a stirrer with a rotational speed of 30 rpm.

While stirring the contents, nitrogen gas was blown in to replace oxygen in the reaction system.

During this time, hot water was passed into the jacket to adjust the internal temperature to 50°C.

Next, chlorine gas was passed through the suspension in the reaction tank to saturate the reaction system with chlorine gas.

Thereafter, the chlorination reaction was initiated by irradiation with ultraviolet light.

The reaction system is always saturated with chlorine gas, and 1 of the introduced gas
The amount of chlorine gas introduced was adjusted so that 1/0 of the amount was released.

After 16 hours of reaction, the chlorine content of the resin reached 70%.

Thereafter, ultraviolet irradiation and introduction of chlorine gas were stopped, and nitrogen gas was passed to replace the chlorine gas in the reaction system.

The obtained suspension was filtered, and the by-produced hydrochloric acid was diluted with water, and then a dilute aqueous sodium hydroxide solution was added to neutralize it.

Solids were separated from the suspension using a centrifuge, washed with water, dehydrated and dried to obtain chlorinated polyvinyl chloride having an average degree of polymerization of 620.

(b) or p) To 100 parts of the chlorinated polyvinyl chloride obtained in the above (a), 10 parts of calcium carbonate and 10 parts of the solvents listed in Table 1 below were separately blended and mixed well.

65 g of the above compound was filled into a press plate mold with a thickness of 2 mm and a size of 140 parts m x 140 mm, and the temperature was 180°C.
Heat and pressure was applied for 5 minutes at a surface pressure of 60 kg/iG.

Thereafter, the pressure was rapidly removed to obtain a white resin foam having uniform, fine, closed cells.

The density of this resin foam was as shown in Table 1 below.

(q) Chlorinated polyvinyl chloride 10 obtained in (a) above
0 parts, 10 parts of calcium carbonate, 3 parts of dibutyltin malate
parts, and lubricants (wax OP and Calcol 86)
0.5 part of each was blended and mixed well.

This formulation was extruded through an 8 mm diameter round bar die in an extruder with a length/diameter ratio of 20 and a compression ratio of 3.

The heating of the extruder was adjusted so that the temperature at the resin supply port was 40°C, and the temperature was gradually increased as it approached the nozzle until the nozzle temperature reached 170°C.

During the process, just before the resin melted, propane gas was injected in an amount of 5 parts per 100 parts of resin extrusion.

As a result, a resin foam having a density of 0.9879/cyl- was obtained.

Example 2 (a) The chlorination reaction was carried out in the same manner as in Example 1 (a) except that the reaction time was changed to 50 hours. Chlorinated polyvinyl chloride was obtained.

(b) or e) Calcium carbonate and the solvent listed in Table 2 below are blended with the chlorinated polyvinyl chloride obtained in (a) above in the same manner as in Example 1(b) or p),
A resin foam was obtained by processing in the same manner as in Example 1(b) to p).

The densities of these resin foams were as shown in Table 2 below.

Example 3 (a) A chlorination reaction was carried out in the same manner as in Example 1 (a) except that the reaction time was changed to 3 hours, and an average polymerization degree of 950 and a chlorine content of 60% were obtained. Chlorinated polyvinyl chloride was obtained.

(b) or e) Calcium carbonate and the solvent listed in Table 3 below are blended with the chlorinated polyvinyl chloride obtained in (a) above in the same manner as in Example 1(b) or p),
A resin foam was obtained by processing in the same manner as in Example 1(b) to p).

The densities of these resin foams were as shown in Table 3 below.

Comparative Example 1 (a) or d) Polyvinyl chloride with an average degree of polymerization of 1000 and a chlorine content of 57% (not post-chlorinated)
Calcium carbonate and the solvent listed in Table 4 below were blended in the same manner as in Example 1(b) to p).
Although it was treated in the same manner as (b) to p), it did not foam at all.

The resin density after treatment was as shown in Table 4 below.

From the above results, it is clear that a good resin foam can be obtained from chlorinated polyvinyl chloride with a chlorine content of 60 to 75% by the method of the present invention, but if polyvinyl chloride that has not been post-chlorinated is treated in the same way. However, it was found that a good resin foam could not be obtained.

Example 4 (a) or d) To 100 parts of chlorinated polyhinyl chloride obtained in Example 1(a), 10 parts of calcium carbonate,
3 parts dibutyltin malate, polymeric lubricant (wax 0P)
) and 5 parts of the solvents listed in Table 5 below were separately blended and mixed thoroughly.

These formulations were prepared with a length/diameter ratio of 20 and a compression ratio of 3.
It was extruded through a round bar mold with a diameter of 8 mm using an extruder.

The heating of the extruder was adjusted so that the temperature at the resin supply port was 40°C, and the temperature was gradually increased as it approached the nozzle until the nozzle temperature reached 170°C.

As a result, a white resin foam having closed cells was obtained.

The densities of these resin foams were as shown in Table 5 below.

From the above results, it was found that even when the method of the present invention is applied to foaming a resin using an extruder, excellent results can be obtained.

Example 5 (a) or d) To 100 parts of the chlorinated polyvinyl chloride obtained in Example 1(a), 10 parts of polyvinyl chloride with an average degree of polymerization of 1000, 10 parts of calcium carbonate, and 3 parts of dibutyltin malate. , polymeric lubricant (wax 0P) 0.5
1 part and 5 parts of the solvents listed in Table 6 below were separately blended and thoroughly mixed.

These blends were extruded using an extruder in the same manner as in Examples 4(a) to d) to obtain resin foams.

The densities of these resin foams were as shown in Table 6 below.

From the above results, it was found that according to the method of the present invention, a good resin foam can be obtained even if other resins are added to chlorinated polyvinyl chloride.

Example 6 (a) In Example 1 (a), propylene-vinyl chloride copolymer (propylene content 3% by weight, average degree of polymerization 500) was used instead of polyvinyl chloride, and the reaction time was 10 hours. Other than that, the chlorination reaction was carried out in the same manner as in Example 1(a), and the average degree of polymerization was 350 and the chlorine content was 66%.
A chlorinated propylene-vinyl chloride copolymer was obtained.

(b) or e) Calcium carbonate and the solvent listed in Table 7 below were added to the chlorinated propylene-vinyl chloride copolymer obtained in (a) above in Example 1(b) or p.
) and treated in the same manner as in Example 1(b) to p) to obtain a resin foam.

The densities of these resin foams were as shown in Table 7 below.

From the above results, it was found that a good resin foam can be obtained even when a chlorinated vinyl chloride copolymer is foamed by the method of the present invention.

Example 7 (a) To 100 parts of the chlorinated polyvinyl chloride obtained in Example 1(a), 10 parts of calcium carbonate, 3 parts of dibutyltin malate, 0.5 part of an external lubricant (wax 0P), and an internal lubricant (Calcol) were added. ) and mixed well.

This mixture was rolled around a roll at 190°C for 3 minutes,
I made a roll sheet.

This rolled sheet was coarsely ground to produce pellets.

(b) or e) Pellet 10 obtained in (a) above
0 g was placed in a beaker with a capacity of 200 cc, and this was placed in a jacketed 11 pressure autoclave.

Appropriate amounts of the solvents listed in Table 8 below were separately charged to the outside of the beaker containing the pellets.

Hot water at 90° C. was circulated through the jacket for 24 hours to impregnate the pellets with 10% by weight of each solvent separately.

This pellet was used and treated in the same manner as in Example 1(b) to p) to obtain a resin foam.

The densities of these resin foams were as shown in Table 8 below.

From the above results, it was found that in the method of the present invention, a good resin foam can be obtained even when resin pellets are impregnated with a solvent and foamed.

Claims (1)

[Claims] 1 Add 100 parts by weight of chlorinated vinyl chloride resin with a chlorine content of 60 to 75% by weight and a boiling point of 150°C to 16°C.
Containing 1 to 50 parts by weight of one or more solvents selected from hydrocarbon solvents, ether solvents, ketone solvents, and ester solvents at 0°C, and foaming by heating. A method for producing a chlorinated vinyl chloride resin foam, characterized by: