JPS6291503A - Production of chlorinated vinyl chloride resin - Google Patents

Abstract

PURPOSE:To produce the titled resin excellent in gelling property, heat stability and initial coloration, by emulsion-polymerizing vinyl chloride or a mixture thereof with a comonomer in the presence of H2O2 and a surfactant and post- chlorinating the formed (co)polymer. CONSTITUTION:100pts.wt. vinyl chloride monomer or mixture thereof with a monomer copolymerizable therewith (e.g., ethylene) is emulsion-polymerized at 40-70 deg.C in an aqueous medium containing 0.001-1pt.wt. H2O2 as a polymerization initiator, 0.0001-0.1pt.wt. anionic surfactant (e.g., higher alcohol sulfate), 0-10pts.wt. modifier (e.g., trichloroethylene), etc., to obtain a particulate polymer comprising an aggregate of an emulsion polymer of a particle diameter of 0.01-10mum and having no dispersant film on the surface of a particle and having a particle diameter of 0.2-8mm. This particulate polymer is ground, as necessary, and post-chlorinated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a chlorinated vinyl chloride resin. More specifically, in producing chlorinated vinyl chloride resin, the pre-process of producing vinyl chloride resin is carried out using a specific polymerization method, and then post-chlorination is performed according to a conventional method to improve gelatinability and thermal stability. The present invention relates to a method for producing a chlorinated vinyl chloride resin having excellent properties and initial colorability.

[Prior art/problems to be solved by the invention] Vinyl chloride resin (hereinafter referred to as PVC) has the property of improving the softening temperature of vinyl chloride resin (hereinafter referred to as PVC).
(hereinafter referred to as cpvc) is produced by post-chlorinating PvC.

PvC as a raw material resin for CPVC is partially saponified polyvinyl alcohol, suspension stabilizers such as methylcellulose, hydroxypropylmethylcellulose, and lauroyl peroxide, di-2-ethylhexyl peroxyneodecanoate, t-butylperoxyneodecanoate, etc. Eight, α.

Polymerization is generally carried out by a suspension polymerization method using an oil-soluble polymerization initiator such as α'-azobis-2,4-dimethylvaleronitrile.

However, PvC obtained by the suspension polymerization method is usually inferior to PvC obtained by the emulsion polymerization method in terms of gelability, plasticizer absorption, etc. because the particle surface is usually covered with a dispersant film. Are known. If CPVC is produced using PVC obtained by this suspension polymerization method, CPVCL, which has poor gelling properties, initial coloring properties, and thermal stability, cannot be replaced.

On the other hand, PvC obtained by emulsion polymerization has extremely small basic particles, has good gelling properties and plasticizer absorption, and is superior to PVC obtained by suspension polymerization in terms of processability. The polymer obtained by salting out is fine and has a low bulk density, contains many impurities, and has poor thermal stability.

If CPVC is produced using PvC obtained by the above-mentioned emulsification method, problems such as poor thermal stability due to the contamination of PvC with impurities arise in CPVC, and costs increase due to the salting-out operation when obtaining PvC. etc. are CP as is.
It also affects VC costs.

Therefore, PVC has the advantages of suspension polymerization and emulsion polymerization, that is, it has a low impurity content, the basic particles form aggregates like emulsion polymers, and it has a particulate appearance similar to that of suspension polymerization. CPVC made from PvC as a raw material resin, which has no dispersant film on the surface of the particulate matter and can be obtained without salting out operations etc.
It is thought that it has excellent characteristics different from CPVC, which uses PVC as a raw material resin by suspension polymerization method or emulsion polymerization method, and can be manufactured at low cost.

The present invention has been made in order to obtain a CPVC which is superior in gelation properties, thermal stability and initial coloring properties as compared to CPVC produced by conventional methods.

[Means for Solving the Problems] The present invention provides Pv
This was done based on the discovery that producing CPVC from C can improve gelling properties, thermal stability, and initial coloring properties compared to CPVC made by conventional methods, and the vinyl chloride monomer When polymerizing a monomer or a mixture with other monomers that can be copolymerized with it in an aqueous medium, hydrogen peroxide is used as a polymerization initiator in an amount of 0.0001 to 0.1% based on the monomer.
Chlorinated vinyl chloride characterized by starting emulsion polymerization in the presence of a surfactant (wt%, same hereinafter) to obtain a particulate polymer consisting of aggregates of emulsion polymer, and then post-chlorinating this. Related to the manufacturing method of resin.

[Example] Other monomers that can be copolymerized with the vinyl chloride monomer used in the present invention include, for example, olefins such as ethylene and propylene, vinyl esters such as vinyl acetate and vinyl stearate, and methyl acrylate. , acrylic esters such as methyl methacrylate, acid esters and anhydrides such as maleic acid or fumaric acid, nitrile compounds such as acrylonitrile, and vinylidene compounds such as vinylidene chloride.

In the present invention, when the vinyl chloride monomer or a mixture with other monomers copolymerizable with the vinyl chloride monomer is polymerized in an aqueous medium, the surface activity of the vinyl chloride monomer is o, ooot ~ 0.1% with respect to the monomer. Polymerization is initiated using hydrogen peroxide as a polymerization initiator in the presence of a polymerization agent.

The surfactants used in the present invention include higher alcohol sulfates, alkylbenzene sulfonic acids, dialkyl sulfosuccinates, anionic surfactants such as sodium salts and ammonium salts of α-olefin sulfonic acids, polyoxyethylene alkyl ethers, Examples include nonionic surfactants such as polyoxyethylene alkyl phenyl ether, sorbitan fatty acid ester, polyoxyethylene sorbicun fatty acid ester, glycerin fatty acid ester, and polyoxyethylene oxypropylene block copolymer. It is preferable to use an anionic surfactant because of the high quality of PvC produced.

The type and amount of the surfactant used will affect the particle size and polymerization stability of the granular polymer, which is made up of aggregates of emulsion polymers obtained by polymerization. It may be selected so that the polymer can be changed.

The general amount of surfactant used is o, ooot to 0.1 part, preferably 0.1 part to 100 parts (parts by weight, the same applies hereinafter) of vinyl chloride monomer or a mixture of this and other monomers. is 0.001 to 0.05 part. If the amount of surfactant used is out of the above range, emulsion polymers and particulate polymers consisting of aggregates will not be produced, resulting in a latex-like product, or conversely, the polymerization rate will be extremely reduced.

Although it is necessary to have a surfactant present at the beginning of polymerization, there is no particular limitation, as surfactants, suspension stabilizers, etc. may or may not be added during the polymerization. .

Hydrogen peroxide, which is a polymerization initiator, may be used alone or as a redox catalyst in combination with a reducing agent. Although there are no particular limitations, hydrogen peroxide may be used as a redox catalyst from the viewpoint of increasing the polymerization rate. It is preferable to use

Specific examples of the reducing agent include sodium sulfite, sodium hydrogen sulfite, Longalift, ascorbic acid, and the like.

In the aqueous medium, a surfactant and hydrogen peroxide are added to water, and if necessary, a reducing agent, trichlorethylene,
Molecular weight regulator such as 2-mercaptoethanol, hydrochloric acid,
It is an aqueous liquid containing an I)II regulator such as sodium dihydrogen phosphate.

Hydrogen peroxide used in the polymerization reaction, a molecular weight regulator,
The reducing agent, pH adjuster, etc. may be added to the water all at once initially, or may be added in portions during the polymerization reaction.

When hydrogen peroxide is used as a redox catalyst, in order to avoid rapid polymerization reactions and make the polymerization rate as uniform as possible, either hydrogen peroxide or a reducing agent is initially charged in bulk, and the other is added continuously. Alternatively, it is preferable to add the hydrogen peroxide and the reducing agent intermittently, or to add both hydrogen peroxide and the reducing agent continuously or intermittently from their respective addition ports.

The amount of hydrogen peroxide used in the present invention is not particularly limited and may be selected depending on the polymerization temperature, the heat removal ability of the polymerization machine, etc. The amount ranges from 0.001 to 1 part per 100 parts of the mixture with the polymer.

The amount of the molecular weight regulator used is usually 0 to 10 parts, preferably 0 to 5 parts, and the amount of the reducing agent is usually 0 to 0.5 parts, preferably 0.01 parts, per 100 parts of the monomer. ~0.1
Department.

The ratio of vinyl chloride monomer or a mixture with other monomers that can be copolymerized with it and water is determined by the final water/monomer ratio from the viewpoint of productivity, heat removal ability in the polymerization machine, etc. 171 to 5/1 is preferable, and 1/l to 3/1 is more preferable. In addition, when using a mixture of vinyl chloride monomer and other monomers that can be copolymerized with it, the composition must contain 70% or more of vinyl chloride monomer in the entire mixture for quality reasons. It is preferable from this point of view, and more preferably 85% or more.

The temperature range of the polymerization reaction in the present invention is usually 40 to 75°C.
However, it is not particularly limited.

According to the method of the present invention, P is composed of aggregates of basic particles (particle size: 0.01 to 10 μl), which is an emulsion polymer, and has a particle size of about 0.2 to 8 mm without a dispersant film on the particle surface.
Particulate polymer of vC can be changed.

When the PVC thus obtained is post-chlorinated by a conventional post-chlorination reaction, cpv by the method of the present invention is obtained.
You can get c.

Examples of the method for the post-chlorination reaction include conventional methods such as an aqueous suspension method, an organic solvent suspension method, a solution method, and a gas phase method, which may be employed without particular limitation.

In the post-chlorination reaction, the particulate polymer may be separated from the reaction liquid during PvC production and used for chlorination as it is, or the particulate polymer may be separated from the reaction liquid and then crushed and then chlorinated. It is preferable to pulverize the particulate polymer and then chlorinate it from the viewpoint of uniformity of the chlorination reaction, chlorination reaction rate, quality as a CPVC, and the like.

The granular polymer may be pulverized using a pulverization method normally used for pulverizing solids, such as an impeller breaker,
A pulverizer such as a ball mill or an impact mill may be used.

The CPVC obtained in this way has a shorter gelation time than CPVC produced by suspension polymerization, and has a higher initial coloring property.
It has good thermal stability and has extremely excellent characteristics.

The method of the present invention will be explained below based on Examples and Comparative Examples, but the present invention is not limited thereto.

In addition, the following physical property evaluation was performed according to the following method.

(particle size distribution) The sieve-shaking method was used.

(bulk specific gravity) According to JIS K 6721.

(Porosity) Mercury intrusion porosimeter (5
-7118 model), absolute pressure 11~LQLlpsi
The porosity was determined by determining the volume of mercury injected per 100 g of resin between 7IllJ and 100g of resin.

(CPVC gelling time) cpvctoo part, 7 parts of Kane Ace B-22 (manufactured by Kanebuchi Kagaku Kogyo Oki), tin-based stabilizer (TVS-8 made by Nitto Kasei Oki)
831) 2 parts and 2 parts of stearic acid (manufactured by NOF ■) were stirred for 5 minutes using a homogenizer (10000 rpo+)
54g of the compound prepared by
pI11. , the time from when it was put into the chamber at a temperature of 180°C to when it reached the maximum torque was measured.

(Initial coloring properties and thermal stability of CPVC) 100 parts of CPVC, 10 parts of Kaneka A 7.8-22 (manufactured by Kanekabuchi Chemical Co., Ltd.), 2 parts of tin-based stabilizer (TVS-8831, manufactured by Nitto Kasei Ltd.), slipping material After mixing 0.7 parts of VPII-4 (manufactured by Hoechst) and 1 part of stearic acid,
A roll sheet with a thickness of 1 ma+ was produced under conditions of 185° C. x 3 minutes, and a press plate with a thickness of 5 mm (pressing conditions: 190° C. x 10 minutes) was made from the rolled sheet, and its initial colorability was evaluated. Further, the rolled sheet was placed in a gear oven at 195° C., and the sheet was taken out every 15 minutes, and the time until blackening was determined for 711 seconds.

Example 1 (Polymerization of vinyl chloride monomer) 2 parts of water (1 part, 0.017 parts of Rongalit, 0.005 parts of sodium lauryl sulfate) were charged into a polymerization machine with an internal capacity of 16N, and the air inside was pumped out using a vacuum pump. After removing it, 100 parts (4.5 kg) of vinyl chloride monomer was charged, and the temperature was raised to 64°C under prescribed stirring conditions, and then hydrogen peroxide diluted with water was added at a rate of 0.0015 parts/hour. It was added continuously using a metering pump at a constant speed.The pressure inside the can was lower than the steady pressure.
．． Addition of hydrogen peroxide was stopped when the amount decreased by 5 kg/c- (total hydrogen peroxide addition f1: 0.0084 parts), and at the same time, unreacted monomers were collected (polymerization time: 4 hours and 10 minutes). The post-polymerization slurry containing particulate polymer was dehydrated and a portion thereof was dried to obtain PvC.

The obtained PvC is a very sharp granular polymer with an average particle diameter of 1550 μm, and observation using a scanning electron microscope shows that the granular polymer has a basic particle size (0,1~ 2 μm), and no dispersant film was observed in PvC produced by the usual suspension polymerization method.

Moreover, the porosity was 24.7, and the bulk specific gravity was 0.613, both of which were large.

(Post-PVC chlorination) The granular polymer (average particle diameter 1550 μm) dehydrated from the slurry after polymerization was processed using a pantam mill to obtain an average particle diameter of 250 μm.
Grinded to μm particles.

900 g of this pulverized PVC and 5 LOOg of water were charged into a reactor with an internal volume of 8 g equipped with a stirrer, sufficiently stirred to form a suspension, and nitrogen gas was blown into the reactor to replace the air in the reactor with nitrogen. . After that, chlorine gas was introduced into this suspension to saturate the reaction system with chlorine, and the reactor was heated to 50°C.
PvC was chlorinated under irradiation with a high-pressure mercury lamp while supplying an excessive amount of chlorine gas. After 2.4 hours, the chlorine content of the product reached 64%, at which time the high-pressure mercury lamp irradiation and the introduction of chlorine were stopped, and nitrogen gas was passed to replace the chlorine in the reactor with nitrogen. Hydroxyamine hydrochloride (1.0%) was added to the CPVC and left to stir to completely remove chlorine, then filtered, the CPVC was thoroughly washed with ion-exchanged water, and then an aqueous sodium hydroxide solution was added to neutralize it. After that, it was further washed with water and then filtered and dried to obtain CPVC.

The obtained CPVC had excellent gelation properties, initial coloring properties, and thermal stability. The results are shown in Table 1.

Comparative Example 1 Potassium persulfate 0.085 parts/sodium sulfite 0.034 parts were used in place of the hydrogen peroxide/Rongalite polymerization initiator used in Example 1, and both were charged into the polymerization machine at the same time as water. Polymerization was carried out in the same manner as in Example 1 except that sodium was not used, and PvC was obtained. Furthermore, crushing
Chlorinated to obtain CPVC.

The obtained PvC was a granular polymer with an average particle diameter of 2420 μl and no dispersant film on the particle surface, as in Example 1. In addition, the initial colorability and thermal stability of the obtained CPVC were fair, but not satisfactory. The results are shown in Table 1.

Comparative Example 2 (Suspension Polymerization Method) Contents: 200 parts of water in which 0.06 parts of hydroxypropyl methyl cellulose was dissolved in a polymerization machine of atefI, 0.0 parts of t-butyl peroxyneodecanoate as a polymerization initiator.
After charging 0.024 parts of 18 parts, 3.5.5-)limethylhexanoyl peroxide and removing the air inside with a vacuum pump, 100 parts of vinyl chloride monomer (4.5k
g) was charged, and the temperature was raised to 64°C under prescribed stirring conditions to initiate polymerization, and the internal pressure was lower than the steady pressure, 5 kg/c-
The unreacted monomer was collected when the polymerization rate decreased (polymerization time: 6 hours), and the resulting slurry was dehydrated and dried to obtain PvC.

The obtained PvC was then subjected to a post-chlorination reaction in the same manner as in Example 1 without being pulverized to obtain CPVC.

The obtained PvC had an average particle size of 138 μm, a unique dispersant film was observed on the particle surface, and both the porosity-1 bulk specific gravity was small.

In addition, the gelation time of CPVC was slow and the initial colorability was poor. The results are shown in Table 1.

[Margins below] From the results in Table 1, the gelation time of CPVC of Example 1 was significantly shorter than that of CPVC produced by suspension polymerization method (Comparative Example 2), and the initial coloring property and thermal stability were lower than that of water-soluble persulfate. C using
It can be seen that this is improved over PVC (Comparative Example 1).

[Effects of the Invention] According to the method of the present invention, it is possible to produce a chlorinated vinyl chloride resin that has excellent gelation properties, thermal stability of molded products, and initial coloring properties, and the industrial value of the present invention is It's quite large.

Claims (1)

[Claims] 1 When polymerizing a vinyl chloride monomer or a mixture with other monomers that can be copolymerized with it in an aqueous medium, hydrogen peroxide is used as a polymerization initiator at a concentration of 0.0001 to 0 for the monomer.
．． Initiating emulsion polymerization in the presence of 1% by weight surfactant;
A method for producing a chlorinated vinyl chloride resin, which comprises obtaining a granular polymer consisting of an aggregate of an emulsion polymer, and then chlorinating this.