JPS5810407B2 - Fine-grained sinterable polyvinyl chloride - manufacturing method of molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for the production of sinterable suspension polyvinyl chloride moldings and their use in the production of separators for storage batteries.

It is legal to use polyvinyl chloride in the production of separators for storage batteries! It is knowledge.

Attempts have already been made to use for this purpose products produced by conventional suspension polymerization of vinyl chloride.

Such vinyl chloride suspension polymers, however, usually have an excessive average particle size, which results in a very coarsely porous sintered plate.

However, even finely divided suspension materials have the disadvantage of being highly wettable, which impedes electrolyte permeation.

DE 21 27 654 therefore describes suspension polymers in the presence of known suspension stabilizers, such as alkylcelluloses or hydroxyalkylcelluloses, and also known emulsifiers, such as alkyl sulfates, alkylbenzene sulfonates, etc. or in the presence of an alkali salt of a cydialkyl sulfosuccinic acid ester, it is possible to additionally add non-ionic agents, such as certain block copolymers or condensation products of alkylene oxides, after the preparation. Proposed.

Although the wettability is certainly improved by doing so, the vinyl chloride suspension polymers thus obtained are also not very suitable as separators by themselves.

This is because the polymers exhibit poor processability (when applied with a doctor knife or roller treatment) and have rather unsatisfactory mechanical properties (especially elongation at break and strength at break).

Therefore, in German Patent Application No. 2,127,654, the suspension polymer obtained in this way has a polyvinyl chloride content of 5 to 500
It has been proposed to obtain a molded material that exhibits good sinterability even after finishing the weight percentage.

Although the processability and also the wettability are now improved, this concomitantly deteriorates the mechanical properties of the sintered plate obtained even further.

Furthermore, separators produced in this way also exhibit a tendency to foam due to their high emulsifier content within the accumulator.

These drawbacks are a result of the use of vinyl chloride suspension polymers, for which, in addition to the usual suspension stabilizers and nonionic wetting agents, emulsifiers in the free acid form are used as an alternative to the emulsifiers in the salt form. When using, it can be removed.

The object of the present invention is to subject vinyl chloride to suspension polymerization in an aqueous phase using an oil-soluble polymerization initiator in the presence of a suspension stabilizer, a nonionic wetting agent, and an emulsifier, and then to separate the polymerized product. By drying,
In the method for producing a sinterable fine-grained polyvinyl chloride molding material, an alkylarylsulfonic acid having 3 to 16 carbon atoms or an alkylsulfone having 8 to 16 carbon atoms in the alkyl chain is used as an emulsifier. acid or a mixture of the two sulfonic acids mentioned above.1. The process is characterized in that it is used in an amount of 0.01 to 0.5% by weight, based on monomeric vinyl chloride.

The polyvinyl chloride molding material obtained by the method of the invention has a k value of 60 to 75, a high density of 350 to 500 g/l,
Plasticizer absorption capacity 12-255% by weight Average particle size 15-35μ
m1 particle size distribution 60-98 wt% 33 μm or less 2-35 wt% 33-63 μm 0-4.5 wt% 63-125 μm 0-0.
5% by weight has a diameter of 125 μm or more.

Furthermore, the sinterable fine-grain molded material made of suspension polyvinyl chloride according to the present invention can be used for the production of separators for storage batteries.

Finally, separators for storage batteries produced from moldings according to the invention have a breaking strength of 80 to 150 kg/cm2, 6 to
11% elongation at break, 40-100% water absorption and 0
．． In the case of a flat plate with a plate thickness of 5 mm, 120 to 180
Let the capillary rise height in mm be indicated.

As alkylarylsulfonic acids, naphthalene or benzene dialkylarylsulfonic acids come into consideration, but preference is given to monoalkylarylsulfonic acids, especially monoalkylbenzenesulfonic acids.

The number of alkyl groups is 3 to 16, preferably 8 to 1.
It should contain 4, but especially 10 to 12, carbon atoms.

These alkyl groups may be branched or straight-chain, but the latter is preferred.

These sulfonic acids include, for example, dodecylbenzenesulfonic acid and nonylbenzenesulfonic acid, as well as diisobutylnaphthalenesulfonic acid, diisopropylnaphthalenesulfonic acid and diisobutylnaphthalenesulfonic acid.

Furthermore, alkylsulfonic acids having 8 to 16 carbon atoms, preferably 12 to 14 carbon atoms, are also considered! be done.

The sulfonic acids to be used in the present invention can be used in pure form or as mixtures.

These alkylarylsulfonic acids are especially suitable for the corresponding alkylbenzenes or mixtures of such alkylbenzenes.
Produced by direct sulfonation with S03 or fuming sulfuric acid.

Alkyl sulfonic acids are produced from the corresponding crude oil fraction or paraffin fraction, for example, according to the sulfoxylation method using 5O2102.

The amount of the sulfonic acid used according to the invention is from 0.01 to 0.5% by weight, preferably from 0.08 to 0.3% by weight, based on monomeric vinyl chloride.

As polymerization initiators, customary oil-soluble initiators are added, such as, for example, lauryl peroxide, diisopropyl, peroxydicarbonate or cyclohexylsulfonylacetyl peroxide.

The polymerization reaction is carried out in the presence of suitable suspension stabilizers known per se, such as alkylcelluloses and hydroxyalkylcelluloses.

Examples are methylcellulose or ethylcellulose and hydroxyethylcellulose or hydroxypropylcellulose and their mixed ethers, such as hydroxypropylmethylcellulose.

However, other known suspension stabilizers are also suitable, such as polyvinyl alcohol or partially saponified polyvinyl esters.

These suspension stabilizers are added to the polymerization feed in question.
It is incorporated in an amount of 0.05 to 0.8% by weight, preferably 0.1 to 0.5% by weight, based on monomeric vinyl chloride.

The viscosity of the suspension stabilizer used here is between 200 and 70% based on a 2% concentration by weight solution and a temperature of 20°C.
The value should be 0 cp, preferably 300 to 500 cp.

Additionally, the polymerization reaction is carried out in the presence of conventional nonionic wetting agents.

The wetting agent is present in an amount of 0.01 to 0.1% by weight, preferably 0.01 to 0.05% by weight, based on monomeric vinyl chloride.
used in amounts of

Suitable are in particular sorbicun fatty acid esters, but also polymers or copolymers of alkylene oxides, alkyl esters and aryl esters, such as ethylene oxide or propylene oxide and their alkyl and aryl ethers. It is.

These suspension stabilizers, emulsifier acids and nonionic wetting agents are added to the polymerization solution before the start of the polymerization reaction.

However, it is also possible to pour in portions of up to 50% of these auxiliaries (one or more auxiliaries) continuously or in portions later after the polymerization reaction has begun to proceed.

The second aspect of the invention is that before and optionally also during the polymerization reaction, 30% of the total amount of emulsifier in acid form and optionally additionally the total amount of suspension stabilizer and/or non-ionic wetting agent used. of the emulsifier in acid form, optionally plus the total amount of suspension stabilizer and/or non-ionic wetting agent.
The remaining 70-20% is applied to the produced polymer after separation.

Preferably, in such embodiments, 40 to 60% of the total amount of emulsifier in acid form and optionally further suspension stabilizer and/or non-ionic wetting agent is used.
% prior to or during the polymerization reaction and the remaining 60-40% applied to the polymer after separation.

Separation of the produced polymer from the aqueous solution is carried out according to known techniques, for example, by centrifugation.

The application of the emulsifier acid and optionally the suspension stabilizer and/or nonionic wetting agent ensures as homogeneous mixing of the polymer particles and the emulsifier acid-containing phase as possible and thereby the emulsifier acid-containing phase of the polymer particles. Spraying, for example, should be carried out in a manner that achieves as complete a coverage as possible.

For this purpose, the aforementioned auxiliaries, if solid, are dissolved or dispersed in water or in organic solvents, such as lower alcohols, lower hydrocarbons, or acetone.

If it is in liquid form, it can be applied as is or after dilution with water or the above-mentioned organic solvents.

Solutions or dispersions at concentrations of 1 to 40% by weight, preferably 5 to 20% by weight are suitable.

The spray coating process for polymers separated from aqueous solutions is conventional.
This is carried out in accordance with the spraying method for solutions or dispersions.

Preferably, the centrifuged product is spray coated at the outlet of the centrifuge.

The atomization process can also be carried out during transport by means of a spiral device or by means of a conveying device, such as one operated with air or other inert gas.

Thereafter, it is dried by a conventional method.

According to the second aspect of the present invention, when the entire amount of auxiliary agents (e.g., emulsifiers, etc.) is added before or during the polymerization reaction, certain difficulties that occur during the finishing treatment of the polymer can be solved. is removed.

When the product obtained according to the first aspect of the present invention is centrifuged in a continuously operated tilting centrifuge such as that normally used in the suspension process for finishing polyvinyl chloride,
Residual moisture of the centrifugally filtered polymer is formed in an amount of 40 to 50 parts by weight or more, and this residual moisture cannot be reduced even by reducing the amount charged.

Due to the sticky consistency of the product, and due to the constraints resulting from the large amount of residual moisture, various hindrances can also occur during transportation in the decanter itself, on the way to the dryer, and within the dryer itself. Appears in

Finally, removing such a high degree of residual moisture in the dryer requires significantly more energy consumption.

On the other hand, in the polymer produced according to the above-mentioned second aspect of the present invention, residual water content of 30% by weight or less is obtained during continuous centrifugation, that is, even in the case of, for example, ordinary suspension polyvinyl chloride. A residual moisture content of 100% is achieved.

Thanks to the residual moisture reduced in this way, a considerable amount of energy is saved per unit weight of dry product in the subsequent drying process, and the process can therefore be made significantly more economical.

More than twice as much dry product can be produced with the same energy consumption.

In this case it is also advantageous that the polymer centrifuged to the residual water has a porous, easily friable solidity;
Because of that, it was shipped without any problem.

Another advantage of this second aspect of the invention is that the said charge is prepared from a larger polymerization charge, which is produced with a certain, within the above-mentioned limits, amount of the above-mentioned auxiliaries. The advantage lies in the fact that the partial amounts of these auxiliaries can be adjusted in the desired manner with respect to their properties by varying the subsequently applied amounts of these auxiliaries.

The suspension polymerization of vinyl chloride is carried out at 50 to 70°C.
This is carried out at normal temperature ranges and according to normal preparation techniques.

The resulting suspension polymer should have a value between 60 and 75, preferably between 65 and 70.

They are finished in the usual manner by centrifugation and hot air drying.

The method of the present invention is suitable for the sintering process.
m, preferably having an average particle size (determined by sedimentation analysis) of 15 to 25 μm.

The average particle size distribution (measured by air sieving method) is as follows:

That is, 60-98% 33 μm or less 2-35% 33-63 μm 0-4.5% 63-125 μm 0-0.5% 125 μm or more Bulk density is 3s0-500 g/l, preferably ・400
~450 g/l.

Plasticizer absorption is around 12-25%, preferably around 15-20%.

The improved sinterability of the molded material according to the present invention is recognized as follows.

That is, as can be seen from FIG. 1, uniformly fused particles are produced as a result of the welding that occurs during the sintering process.

(Using n-dodecylbenzenesulfonic acid as an emulsifier).

In contrast, suspension polymers prepared with the use of alkali metal salt emulsifiers always exhibit clear seams at the weld points (FIG. 2 - using sodium n-dodecylbenzenesulfonate as emulsifier).

Separators produced from such sinterable moldings by conventional belt sintering have a flat surface and are highly microporous, yet with sufficient porosity (DIN) for the passage of electrolyte.
50056).

In particular, however, the mechanical properties, especially the elongation at break and the strength at break, are considerably improved.

Moreover, these moldings do not exhibit any processing disadvantages and do not tend to be easily placed on belts or to form a film on rollers.

Finally, the separators produced from the moldings according to the invention have good wettability and do not exhibit any foaming during charging of the battery.

The sintered plate produced from the shaped material according to the invention has a
When measured on a flat plate with a thickness of mm, it exhibits the following properties.

That is, the breaking strength is 80 to 150 kg/crib.

Preferably 90-130 kg/d1 Elongation at break 6-11%, preferably 6,5-9%, Water absorption 40-100% by weight, preferably 50-80% by weight, Capillary rise height 120-180 mm.

Preferably 140 to 160 mm The sinterable and fine-grained shaped material made of suspension polyvinyl chloride according to the invention is excellently suitable as a sintered shaped material, and for this purpose, other ingredients such as an emulsion may be added. There is no need to mix it with polymers, etc.

Owing to the above-mentioned excellent mechanical and electrical properties as well as sinterability, these shaped materials are used in particular for the production of separators for batteries, in particular accumulators.

They are useful, however, also for other applications, in which sinterable porous synthetic resin materials are particularly desired, such as for cooling towers and irrigation towers. It is suitable for the production of fillers, filters, separators, ion exchange materials, water evaporation parts of heating devices, and porous moldings for flower pots and the like.

The above-mentioned customization of the suspension method polyvinyl chloride sinterable fine-grain molded material was carried out according to the following measurement method.

That is, the deposited weight is determined according to DIN Regulation 53468.

Plasticizer absorption: Centrifuge beaker fitting tip (DI
Tightly attach a filter paper soaked with di-2-ethylhexyl phthalate (dioctyl phthalate - DOP) to the perforated inner bottom of a laboratory centrifuge (N58970E), then weigh the filter paper together (weight ml)
.

Next, a polymer sample of 10.0.9 is weighed (weight m2) into this cup, followed by about 20 g of I) OP and left to stand for about 5 minutes.

. Then, at the bottom of the perforated cup, 25,000 to 2
Centrifugation is performed for 60 minutes at a centrifugal acceleration of 6000 ml 5ec2.

The outside of this pot is wiped with filter paper to purify it, and the contents are weighed (weight In3).

The plasticizer absorption, which is a measure of the porosity of the polymerization suspension in question, is calculated by (in weight percent).

All listed values are average values of 10 individual measurements.

Determination of average particle diameter of polymer by sedimentation analysis = 1.82 g
of polyvinyl chloride were dispersed in 600 ml of a well-degassed 0.09% strength sodium pyrophosphate solution and dropped using a Satorius sedimentation balance model 4600 at a recording paper feed rate of 120 mm/h. Trends were measured.

Calculations were made using the well-known Stokes equation, and the particle radius was determined.

The measurement of the particle size distribution by air sieving analysis is carried out in accordance with DIN standard design No. 53734.

Manufacturing of sintered flat plates: The production of the separators takes place in a continuous belt sintering machine.

In this case, polyvinyl chloride powder is placed in a constant layer thickness on an endless steel belt and guided through a slot in which sintering takes place.

However, the electric heating of the furnace is adjusted to 350°.

By varying the belt speed, the residence time of the polyvinyl chloride powder in the sintering zone and thus the intensity of the sintering are adjusted.

The belt speed is adjusted to a value between 2.0 and 2.3 m/min, preferably 2.2 m/min, resulting in an electrical resistance of 1.6 mΩ/dm2 for the finished separator. .

The separator in question is manufactured with a plate thickness of 0.50 mm and a rib thickness of 1.1 mm.

Measurement of breaking elongation and breaking strength: The breaking elongation (elongation under breaking force) and breaking strength are measured according to DIN regulation 53455 - Elongation test of synthetic resins.

Since the standard sample could not fit into the entire rake, a 60 x 140 mm test piece was cut from the sintered flat plate.

The test was carried out on an elongation tester (DIN51220,
After storage for 16 hours in a standard climate (DIN 50014/1), corresponding to the general conditions for category 1 and DIN 51221), at 23±2° C. and 50±5% relative air humidity.

Test speed (speed at which both fixed clips move away from each other)
is a value such as 50 mm/min and 10%.

The force measurement range is around 100kp.

The force and extension recordings are made on the chart section via a recorder.

The deflection proportional to the elongation (diagram sheet: format) is enlarged to 5=1 and recorded.

The elongation is based on a free fixed length of 100 mm.

Measuring the electrical resistance: The investigation of the electrical resistance of the separator is carried out through the measurement of the so-called internal resistance of the battery, ie the resistance which is measured in the test arrangement (cell) created for this purpose.

The difference in cell resistance with and without a separator indicates the negative resistance of the separator.

The test battery itself is made up of one positive plate and one negative plate (pbo and pb), and these plates are 7
They are installed parallel to each other with an interval of mm.

As electrodes, flat plates of such size and construction as are used in lead-acid batteries are employed.

Just between these two electrodes, there is a shaped sized 1
The separator in question is located within the 00 x 100 mm gap.

The test cell is filled with 1.28 density sulfuric acid and fully charged.

Measuring such low ohmic internal resistances is possible using a direct-reading micro-ohmmeter (model EMT 326, manufactured by Lahr's Electromestechnik, Wey, Franz, Kerr and Deh).
It is carried out with.

However, it is assumed that the ohmmeter is connected to both electrodes.

This measurement is performed using an AC power supply.

Measurement of water absorption: DIN 51056 as a measure of the porosity of the separator
Helps with water absorption.

In that case, the water absorption of the plate was determined gravimetrically after being immersed in water at 40°C for 24 hours.

Measurement of Capillary Rise Height: As a measure of the wettability of the separator and to characterize the porosity, it is useful to investigate the capillary rise height.

In this case, a 1 cm wide strip of the separator is placed in a test tube filled with water to a height of 1.5 cm.

As capillary rise height, the wettability height after an immersion time of 10 minutes is given in mm.

The invention is illustrated by the examples below, in which the values obtained for the respective products and separators produced therefrom are summarized in Tables 1 and 2.

Example 1 Mixture: 440 parts by weight of vinyl chloride, 870 parts by weight of demineralized water, 2.2 parts by weight of methylsululose (viscosity: 400 cp).
(2% by weight solution, 20°C) 1.1 parts by weight of n-toxybenzenesulfonic acid 0.22 parts by weight of polyoxyethylene sorbitan monolaurate 0.088 parts by weight of diisopropyl peroxydicarbonate The resulting mixture is polymerized in a 15001 J kettle (VA steel, impeller stirrer) for 7 hours at 59° C. and 150 revolutions per minute.

The resulting fine-grained polymer slurry is centrifuged on a decanter, and the wet items are heated with hot air (inlet 1) in a current dryer.
Dry at 50°C, outlet 85°C.

Example 2 Mixture 440 parts by weight of vinyl chloride 870 〃 〃 Demineralized water 1.32 〃 〃 Methyl cellulose (viscosity 4
00cp, 2% by weight solution, temperature 20℃) 0.06 〃 〃 n-dopasilbenzenesulfonic acid 0.13 〃 〃 Polyoxyethylene, sorbitan monolaurate 0.008 〃 〃 Consisting of diisopropyl peroxydicarbonate The material is polymerized according to the conditions of Example 1 and then dried.

Example 3 Mixture 440 parts by weight of vinyl chloride 870 〃 〃 Demineralized water 2.2 〃 〃 Methylcellulose (
Viscosity 400 cp, 2% by weight solution, temperature 20°C) 1.1 〃 〃 n-alkanesulfonic acid, chain length C12 to C16, main component C14 0.02〃 〃 Polyoxyethylene,
Sorbitan monolaurate 0.088〃〃〃 Consisting of diisopropyl peroxydicarbonate is polymerized according to the conditions of Example 1 and then dried.

Comparative Example Mixture: 440 parts by weight of vinyl chloride 870 〃 〃 Demineralized water 2.2 〃 〃 Methylcellulose (2% by weight solution to viscosity 4000, temperature 20°C) 1.1 〃 〃 Na salt of n-1” acylbenzenesulfonic acid 0.22 〃 〃 Polyoxyethylene, sorbitan monolaurate 0.088 〃 〃 Diisopropyl peroxydicarbonate is polymerized according to the conditions of Example 1 and then dried.

Identification data for the vinyl chloride suspension polymer obtained on the upper side of Table 1: Example 1 Example 2 Example 3 Values for comparative examples
68.066.364.968.8 High density (g/l
) 420480470400 Plasticizer absorption, dioctyl phthalate (wt%) 15 14 15 1
8 Average grain diameter (μ) 2125 2321 Sieve analysis (%) 33μm or less 95.073.987.596.03
3-63 μm 4,024.1 12.0 3.
063-125μm 0.81.6 0.4
0.8125μm or more 0.2.0.4 0.1 0
．． Table 2 Identification of separators manufactured from the above materials:
Example 1 Example 2 Example 3 Comparative elongation at break, %
96.57.8.

, 6 (average from 4 straight shots) Breaking strength)kp/'') 13013010565(
Average of 4 values) Water absorption, weight % 58556055 Capillary rise height, mm 150 145160140 Electrical resistance, mQ/
drrf' (for plate thickness 0.57mm) 1,6 1.61.61
．． 6 Example 4 Mixture with 440.00 parts by weight of vinyl chloride 870.00 〃 Demineralized water 2.2 〃 Methyl cellulose (viscosity 440 cp, but at 20°C per wt % solution) 0.66 〃 n -Pi silbenzenesulfonic acid 0. 22 〃 Polyoxyethylene sorbitan monolaurate 0.088 〃 Polymerization consisting of diisopropyl peroxydicarbonate in a 1500 liter kettle (VA steel, impeller stirrer) for 7 hours at 59°C and 150 revolutions per minute. I let it happen.

The resulting finely divided polymer slurry was centrifuged on a decanter.

This centrifugation product contained approximately 30% water.

0.44 parts by weight of n-dodecylbenzenesulfonic acid was applied onto the material emerging from the decanter, now prior to its entry into the current dryer.

The application of the sulfonic acid was in the form of a 10% strength aqueous solution and was carried out via a nozzle with the aid of an actual pump.

The polymer thus treated was then dried in a current dryer with hot air (inlet 150°C, outlet 85°C).

The properties of the dried polyvinyl chloride as well as the separators made therefrom are summarized in Table 3.

If the polymerization reaction was carried out using the full amount of emulsifier as described in Example 1, then the polymer obtained by the same separation scheme was about 50% water.

(In the case of a polymer with a moisture content of 25 to 30% by weight, the finishing performance is around 1800 to 1400 kg/hour under the same conditions, whereas in the case of a polymer with a moisture content of about 50%, it is only about 600 kg/hour. .

) Example 5 Mixture with 440.00 parts by weight of vinyl chloride 870.00 〃 Demineralized water 2.2 〃 Methyl cellulose (viscosity 400 cp, but at 20°C for a 2% solution by weight) 0.66 〃 n-dodecylbenzenesulfonic acid 0.05 〃 Polyoxyethylene・
Sorbitan, monolaurate, consisting of 0.088 parts by weight of diisopropyl peroxydicarbonate was polymerized according to Example 4.

The resulting fine particulate polymer slurry was placed in a decanter and centrifuged.

This centrifuged product contained approximately 25% water.

Following Example 4, 0.44 parts by weight of n-dodecylbenzenesulfonic acid and 0.05 parts by weight of polyoxyethylene sorbitan monolaurate were spray coated.

However, in each case, a 10% aqueous solution was used.

The polymer thus treated was dried in an electric current dryer according to Example 4.

The properties of this dried polyvinyl chloride and the separators made therefrom are summarized in Table 3.

Table 3 Identification of the vinyl chloride suspension polymer obtained and the separators produced therefrom: Example 4 Example 5 Values 65.3 66.0 High density (g/l) 460.0 470.0 Plasticizer absorption; Dioctyl, 5. .

14. . Phthalate (weight%) Average particle diameter (μ) 22.0 25.0 Sieve analysis (%) 33μm or less 89.0 75.033~
63μm 10.0 23.063～
125μm 1.0 2.012
5μm or more 00 Breaking elongation (%) 9.0 10.0 Breaking strength (kp/cm2) 110.0 145
．． 0 Water absorption (Economy section) 58.0 40.
0 Capillary rise height (mm) 150.0 1
25.0 Electrical resistance (mρ/dm, provided that the plate thickness is 0.5 mm) 1.2 In short, the subject matter of the present invention is the fine-grained sintered material as defined in the claims above. The following conditions may be attached to the method for producing a compact molded material.

That is, 1) In a method according to claim 2,
The amount of emulsifier is 0.08 based on monomeric vinyl chloride.
2. In the method according to claim 2, the emulsifier is a monoalkylbenzenesulfonic acid whose alkyl group has 8 to 14 carbon atoms. 3) In the method according to claim 2, an n-alkylsulfonic acid having 8 to 16 carbon atoms is used as an emulsifier; 4) According to claim 2, In the method according to item 2, 40 to 60% of the total amount of emulsifier used, and optionally suspension stabilizer and/or nonionic wetting agent, is added before the polymerization reaction, and optionally the suspension stabilizer and/or nonionic wetting agent. After adding and blending during the process, the remaining amount is 60-40
5) Applying the fine-grained sinterable molded material obtained by the method described in claim 1, item 2 to a sinterable porous synthetic material. 6) A separator for storage batteries made from a molded material obtained by the manufacturing method according to claim 1 or 2 is used for manufacturing resin molded parts, especially separators for batteries. ~1
Breaking strength of 50 kg/i, breaking elongation of 6-11%, 4
This includes a water absorption of 0 to 100% and a capillary rise height of 120 to 180 for a plate with a plate thickness of 0.5 mm.

[Brief explanation of the drawing]

Figure 1 is an enlarged view showing homogeneous melting during sintering of polymer particles obtained using n-dodecylbenzenesulfonic acid as an emulsifier, and Figure 2 is an enlarged view showing the uniform melting during sintering of polymer particles obtained using n-dodecylbenzenesulfonic acid as an emulsifier. FIG. 2 is an enlarged view showing the presence of seams in the sintered and welded portions of polymer particles produced using the method.

Claims (1)

[Claims] 1. By suspension polymerizing vinyl chloride in an aqueous phase using an oil-soluble polymerization initiator in the presence of a suspension stabilizer, a nonionic wetting agent, and an emulsifier, and separating and drying the polymer. In the process for producing finely divided sinterable polyvinyl chloride molding materials, alkylarylsulfonic acids having 3 to 16 carbon atoms or alkyls having 8 to 16 carbon atoms in the alkyl chain are used as emulsifiers. The above production method, characterized in that sulfonic acid or a mixture of both sulfonic acids is used in an amount of 0.01 to 0.5% by weight based on the vinyl chloride monomer. 2. Sinterability of fine particles is obtained by suspension polymerizing vinyl chloride in an aqueous phase using an oil-soluble polymerization initiator in the presence of a suspension stabilizer, a nonionic wetting agent, and an emulsifier, and separating and drying the polymer. In the process for producing polyvinyl chloride molding materials, alkylarylsulfonic acids having 3 to 16 carbon atoms in the alkyl chain, or alkylsulfonic acids having 8 to 16 carbon atoms, or both of the above sulfones are used as emulsifiers. The mixture of acids is used in an amount of 0.01 to 0.5% by weight, based on the vinyl chloride monomer, provided that before and optionally also during the polymerization an emulsifier in the form of the acid mentioned above, optionally furthermore, is used. Adding only 30 to 80% by weight of the total amount used of the suspension stabilizer and/or the non-ionic wetting agent and optionally also the emulsifier in acid form and the suspension stabilizer and/or the non-ionic wetting agent. The remaining amount of the total amount used is 70
20% on the resulting polymer after separation.