JP5650915B2 - Method for producing vinyl chloride hollow particles, vinyl chloride hollow particles, vinyl chloride resin composition, and vinyl chloride molded article - Google Patents

Description

  The present invention relates to a method for producing vinyl chloride hollow particles, a vinyl chloride hollow particle, a vinyl chloride resin composition, and a vinyl chloride molded article.

Vinyl chloride resin (hereinafter sometimes referred to as “PVC”) has excellent physicochemical properties and is less expensive than other resins, and is used in a wide range of molded products. . However, since PVC has a large specific gravity of 1.4, there is a disadvantage that it is heavier than other resins such as foamed polyurethane (d = 0.5 to 0.7).
Therefore, various attempts have been made to reduce the weight of vinyl chloride resin molded products.
For example, a molded body such as a vinyl chloride plate has been tried to be chemically foamed for the purpose of weight reduction (see, for example, cited document 1). Moreover, in order to make vinyl chloride into a high space | gap, the method of removing a vinyl chloride monomer in the middle of superposition | polymerization is proposed (for example, refer patent document 2). Furthermore, in order to ensure the porosity and strength of the hollow resin fine particles, a method using a non-polymerizable organic solvent has been proposed (see, for example, cited document 3).

Japanese Patent Publication No. 11-60868 Japanese Patent Publication No. 11-228606 Japanese Patent Publication No. 2005-54084

However, in a molded body in which a foaming agent is blended with PVC, the expansion ratio is limited, and a desired expansion ratio may not be obtained due to a slight difference in conditions. In addition to closed cells, open cells are included in a considerable proportion. Furthermore, air bubbles may be unevenly distributed depending on the part of the molded product.
Therefore, in a secondary processed molded body such as vacuum forming after heating, the effect of reducing specific gravity may be lost due to gelation, collapse of the cell, deformation of bubbles, and the like.
In addition, when a non-polymerizable organic solvent is used, there is a problem that the manufacturing cost increases.
Under such circumstances, in order to further improve the flame retardancy, hollow particles made of a material similar to vinyl chloride, such as the same as vinyl chloride, including a structural unit derived from vinyl chloride as a part thereof, are required. .

  The present invention has been made in view of the above problems, and while ensuring the excellent characteristics of vinyl chloride itself, it is possible to reduce the weight as a vinyl chloride-based molded product, that is, to ensure a void ratio. Method for producing vinyl chloride-based hollow particles capable of ensuring the next processability and improving strength, vinyl chloride-based hollow particles, vinyl chloride-based resin composition containing the hollow particles, and vinyl chloride-based resin composition It aims at providing the vinyl chloride type molded object obtained by using a thing.

The method for producing the vinyl chloride hollow particles of the present invention comprises:
(1) A monomer component containing vinyl chloride as a main component and a polyfunctional monomer, a polymerization initiator and a dispersant are mixed in a polar medium to prepare a suspension,
(2) The suspension is heated to polymerize the monomer component, and when the polymerization rate of the monomer component is 75% or less, unreacted vinyl chloride is removed to form resin particles,
(3) It includes a step of dehydrating and drying the resin particles.

In the method for producing such vinyl chloride hollow particles,
It is preferable that vinyl chloride is 70% by weight or more of the total monomer components.

The vinyl chloride hollow particles of the present invention are obtained by suspension polymerization in a system containing a monomer component containing vinyl chloride as a main component and a polyfunctional monomer, a polymerization initiator, and a dispersant. The porosity is 25% or more and less than 75%.
In such vinyl chloride-based hollow particles, vinyl chloride is preferably 70% by weight or more of the total monomer components.

Furthermore, the vinyl chloride resin composition of the present invention is
A vinyl chloride resin composition comprising at least the vinyl chloride hollow particles described above and a vinyl chloride resin,
The hollow particles are contained in an amount of 3 to 50 parts by weight with respect to 100 parts by weight of the vinyl chloride resin.

  The vinyl chloride-based molded article of the present invention is characterized by being molded from the vinyl chloride-based resin composition.

  According to the present invention, while ensuring the excellent characteristics of vinyl chloride itself, it is possible to secure a porosity and to reduce the weight as a vinyl chloride-based molded body, to improve the strength, and to perform secondary processing. A method for producing vinyl chloride hollow particles capable of improving the properties, vinyl chloride hollow particles, and a vinyl chloride resin composition containing the hollow particles can be obtained.

  In addition, a vinyl chloride-based molded article obtained using this vinyl chloride resin composition has a physical property such as impact resistance and heat resistance inherent in the vinyl chloride resin and chemical properties such as solvent resistance and acid resistance. In addition to having excellent physicochemical properties, the weight can be reduced as compared with conventional vinyl chloride-based molded articles, and it can be used in various applications.

<Method for producing vinyl chloride hollow particles>
In the method for producing vinyl chloride hollow particles of the present invention, first, (1) a monomer component containing vinyl chloride as a main component (hereinafter sometimes referred to as “vinyl chloride”) and a polyfunctional monomer, polymerization initiation A suspension is prepared by mixing the agent and dispersant in a polar solvent.

<Monomer component>
As the monomer component, it is preferable to use a mixed monomer composed of vinyl chloride, a polyfunctional monomer, and optionally other monomers.

  It is suitable that vinyl chloride is contained as a main component in the monomer component. A main component means that the weight ratio which occupies in all the monomer components is the largest. The amount is suitably 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, and even more preferably 75% by weight or more.

The polyfunctional monomer is added for the purpose of improving the compression strength of the vinyl chloride hollow particles, and the kind thereof is not particularly limited.
For example, di (meth) acrylate such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane di (meth) acrylate, etc. (Meth) acrylate;
Tri (meth) acrylates such as trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate;
Di- or triallyl compounds such as pentaerythrole tetra (meth) acrylate, dipentaerystol hexa (meth) acrylate, diallyl phthalate, diallyl malate, diallyl fumarate, diallyl succinate, triallyl isocyanurate;
And divinyl compounds such as divinylbenzene and butadiene.
These may be used alone or in combination of two or more.

  Although the compounding quantity of the polyfunctional monomer in a mixed monomer is not specifically limited, It is preferable that it is 0.1 weight% or more, and it is more preferable that it is 0.3 weight% or more. The upper limit is not particularly limited, but is suitably 50% by weight or less, and preferably 30% by weight or less. By setting it as this range, the compressive strength of the obtained vinyl chloride hollow particles can be sufficiently ensured while ensuring the characteristics of vinyl chloride.

  Examples of other monomers include monomers having an unsaturated bond copolymerizable with a vinyl chloride monomer. For example, α-olefins such as ethylene, propylene and butylene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; methyl (meth) acrylate, ethyl (meth) acrylate and butyl acrylate (Meth) acrylic acid esters such as phenyl methacrylate; aromatic vinyls such as styrene and α-methylstyrene; vinyl vinyl halides such as vinylidene chloride and vinylidene fluoride; N-phenylmaleimide, N-cyclohexylmaleimide, etc. N-substituted maleimides, (meth) acrylic acid, maleic anhydride, acrylonitrile and the like can be mentioned. These may be used alone or in combination of two or more.

<Polymerization initiator>
The polymerization initiator is not particularly limited as long as it is a compound that generates an oil-soluble free radical that is soluble in the monomer component. Examples thereof include organic peroxides such as benzoyl peroxide, lauroyl peroxide, dibutyl peroxydicarbonate, α-cumylperoxyneodecanoate, and the like. Among these, it is suitable to use a combination of two or more.
Although the addition amount of a polymerization initiator is not specifically limited, 0.01-3 weight part is preferable with respect to 100 weight part of monomer components. More preferably, it is 0.1 to 0.5 part by weight.

<Dispersant>
The dispersant has a role of suspending / dispersing droplets composed of monomer components in the medium and stabilizing the dispersion in the production of the vinyl chloride hollow particles.

The dispersant is not particularly limited. For example, silica, calcium phosphate, magnesium hydroxide, aluminum hydroxide, ferric hydroxide, barium sulfate, calcium sulfate, sodium sulfate, calcium oxalate, calcium carbonate, barium carbonate, magnesium carbonate. Etc. In particular, colloidal inorganic dispersants (for example, colloidal silica, calcium phosphate, etc.) are preferable.
Also, for example, condensation products of diethanolamine and aliphatic dicarboxylic acids, condensation products of urea and formaldehyde, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, polyethyleneimine, tetramethylammonium hydroxide, gelatin, methylcellulose, dioctylsulfosuccinate Nate, sorbitan ester and the like may be used.
Further, for example, those that can be dissolved in a polar medium described later, used in the production of hollow particles, one or more hydrophilic groups described below (hydroxyl group, carboxyl group, amino group, sulfonic acid group, amide group, etc.) And those having a substituent of the above.
As those having a hydroxyl group, those having a carboxyl group, such as carboxymethyl cellulose, poly (meth) acrylic acid, etc., those having an amino group, gelatin, etc., those having a sulfonic acid group, polystyrene sulfonic acid, etc. .
Examples of those having an amide group include polyacrylamides and polyvinylpyrrolidone.

  A preferable dispersant includes a combination of colloidal silica and a water-soluble nitrogen-containing compound.

Examples of the water-soluble nitrogen-containing compound include polyvinyl pyrrolidone, polyethyleneimine; polyoxyethylene alkylamine; polydialkylaminoalkyl acrylate or polydialkylaminoalkyl methacrylate represented by polydimethylaminoethyl methacrylate and polydimethylaminoethyl acrylate; Examples include dimethylaminopropyl acrylamide, polydialkylaminoalkyl acrylamide or polydialkylaminoalkyl methacrylamide represented by polydimethylaminopropyl methacrylamide; polyacrylamide; polycationic acrylamide; polyamine sulfone; polyallylamine. You may use these individually or in combination of 2 or more types.
Of these, a combination of colloidal silica and polyvinylpyrrolidone is suitable. The particle diameter of the hollow particles obtained can be adjusted by the addition amount of colloidal silica and polyvinylpyrrolidone.
In particular, when colloidal silica is used, it is desirable to adjust pH appropriately. The colloidal silica is preferably in an acidic environment.

Yet another preferred dispersant is a combination of magnesium hydroxide and / or calcium phosphate and an emulsifier.
As an emulsifier here, unsaturated polyoxyethylene alkylphenyl ether etc. are mentioned, for example.

Although the addition amount of a dispersing agent is not specifically limited, 0.1-20 weight part is preferable with respect to 100 weight part of monomer components. More preferably, it is 1-20 weight part, More preferably, 3-10 weight part is mentioned.
In particular, when colloidal silica is used, it is adjusted depending on the particle diameter, but may be 1 to 20 parts by weight, preferably 2 to 10 parts by weight, per 100 parts by weight of the monomer component. In the case of using an inorganic salt, 0 to 100 parts by weight is exemplified with respect to 100 parts by weight of the monomer component. When using polyvinyl pyrrolidone, 0.05-2 weight part, Preferably it is 0.1-2 weight part, More preferably, 0.1-1 weight part is mentioned.

<Polar medium>
In order to suspension polymerize the monomer component, it is preferable to use a polar medium.
The polar medium is not particularly limited as long as it is incompatible with the solution containing the monomer component described above. For example, water (deionized water etc.), methanol, ethanol, dimethyl sulfoxide, dimethylformamide and the like can be mentioned. These may be used alone or in combination of two or more. Of these, water is preferable because it is easy to handle.

  For the polar medium, various additives usually used in suspension polymerization methods (for example, crosslinking) such as dispersants, auxiliary stabilizers, pH adjusters, water-soluble polymerization inhibitors, antioxidants, antioxidants, preservatives, etc. Agent) and the like. These additives can use what is normally used in the said field | area. In these additives, higher fatty acids (for example, isostearic acid, stearic acid, n-heptadecanoic acid, palmitic acid, n-pentadecanoic acid, myristic acid, alginate, nonadecanoic acid, n-tridecanoic acid, lauric acid, undecyl It is suitable not to use an acid or the like) or a thickener.

Specifically, the polar medium preferably contains a dispersant and the pH is adjusted.
When silica such as colloidal silica is used as a dispersion stabilizer, polymerization is performed in an acidic environment, so an acid such as hydrochloric acid is added as necessary to adjust the pH of the system to 3-4. Is suitable.
When magnesium hydroxide or calcium phosphate is used, since polymerization is performed in an alkaline environment, it is suitable to adjust the pH of the system to the alkali side.

  When preparing a suspension, specifically, after putting a polar solvent (for example, water), a dispersing agent and a polyfunctional monomer into a pressure vessel (kettle), the pressure is reduced and the VCM monomer is reduced. (Liquefied gas monomer) is added and stirred / mixed. For mixing / stirring the monomer component and the polar solvent, a mechanical stirrer such as a homomixer, a biomixer, or a homogenizer may be used, or an ultrasonic homogenizer may be used. Since the particle diameter of the obtained hollow particles depends on the oil droplet diameter in the suspension, it can be appropriately controlled depending on the type and amount of the dispersion stabilizer, the stirring method, the strength, and the like.

Next, (2) the suspension is heated to polymerize the monomer component, and unreacted vinyl chloride is removed during the polymerization to form resin particles.
In order to polymerize, the suspension obtained is first heated.
The heating temperature can be appropriately adjusted depending on the composition of the monomer component to be used, the molecular weight, the type and amount of the polymerization initiator, and the temperature is, for example, about 30 to 100 ° C, and preferably about 30 to 70 ° C.

  The point in the middle of the polymerization is preferably, for example, any point where the polymerization rate of the monomer component is 75% or less, that is, the point where the polymerization rate of the monomer component becomes about 10 to 70% ± 5%. Therefore, it is preferable that the time is about 40 to 70% ± 5%, and more preferably about 50 to 65% ± 5%. Specifically, when the polymerization rate of the monomer component is around 40% (for example, 40 ± 5%), around 50% (50 ± 5%), around 60%, 70 The time when it became around%. In the present invention, when the polymerization rate is increased, the porosity decreases, and the polymerization rate is proportional to the voids. By setting this range, the void ratio of the hollow particles can be appropriately controlled, and the weight can be reduced. The characteristics of the hollow particles such as can be exhibited to the maximum. In addition, the yield can be improved and productivity can be improved.

  During the polymerization, the time to stop the polymerization can be determined by calculating back from the catalyst amount and the pressure drop (the pressure decreases when the vinyl chloride monomer gas becomes a polymer).

  As a method for removing unreacted vinyl chloride in the middle of such polymerization, since the vinyl chloride monomer exists in a gaseous state, the vinyl chloride monomer is removed with a non-reactive gas such as an exhaust gas method or an inert gas. Examples of such a method are as follows. Of these, the former is preferred.

  By adjusting the timing of removal of unreacted vinyl chloride during the polymerization, the gas can be appropriately escaped from the formed vinyl chloride polymer, and a hollow can be efficiently formed therein.

Further, (3) the resin particles are dehydrated and dried.
For this purpose, for example, a method of heating or the like can be mentioned. Specifically, for example, the obtained slurry made of resin particles may be subjected to, for example, centre dehydration, the resin particles are heated with steam, hot air, and / or placed under reduced pressure. Thereby, hollow resin particles can be obtained.
The dehydration or drying is suitably performed, for example, in a temperature range of about 60 ° C to 160 ° C, and preferably about 80 ° C to 100 ° C. The time for dehydration or drying is not particularly limited, and can be appropriately adjusted depending on the method.
In general, bulk polymerization methods, solution polymerization methods, emulsion polymerization methods, suspension polymerization methods, and the like are known as polymerization methods for vinyl chloride resins. According to other methods, vinyl chloride hollow particles can also be produced.

<Vinyl chloride hollow particles>
The vinyl chloride hollow particles of the present invention (hereinafter sometimes simply referred to as “hollow particles”) are substantially a reaction between vinyl chloride as a main component, a polyfunctional monomer, and optionally other monomers. It is comprised by the polymer obtained by. Since these vinyl chloride hollow particles use a polymerization initiator, a dispersant, a polar solvent, other additives, and the like in the production process, these components may remain as residues.

For example, those hollow particles having an average particle diameter of about 3 to 100 μm are suitable, and preferably about 10 to 80 μm. By setting it within this range, the handling property is improved. In addition, when a molded product is produced using the vinyl chloride hollow particles, the physical properties of the obtained molded product can be improved.
It is suitable that the hollow particles have a porosity of about 20% or more and about 25% or more. The upper limit is suitably about 75% or less and about 70% or less, more preferably about 40% or less (or less), about 38% or less, or about 37% or less. By setting this porosity, it is possible to ensure sufficient weight and strength.
The porosity is a percentage (%) of the volume of the hollow portion in the total volume of the vinyl chloride-based hollow particles. For example, the porosity of the sealed mercury is 2000 kg / cm ² using an AMCO Porosimeter 2000. It can measure by.

<Vinyl chloride resin composition>
The vinyl chloride resin composition of the present invention contains at least a vinyl chloride resin and the vinyl chloride hollow particles described above. The vinyl chloride hollow particles here may be formed not only by the suspension polymerization method but also by other polymerization methods.

  As the vinyl chloride resin, a homopolymer of vinyl chloride (vinyl chloride homopolymer), a monomer having an unsaturated bond copolymerizable with a vinyl chloride monomer, and a vinyl chloride monomer (preferably containing 50% by weight or more) Examples thereof include vinyl chloride resins such as copolymers and graft copolymers obtained by graft copolymerization of vinyl chloride monomers with polymers. These polymers may be used alone or in combination of two or more.

  Examples of the monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer include the same polyfunctional monomers and other monomers as described above.

  The polymer for graft copolymerization of vinyl chloride is not particularly limited as long as vinyl chloride is graft-polymerized. For example, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene -Ethyl acrylate copolymer, ethylene-butyl acrylate-carbon monoxide copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, acrylonitrile-butadiene copolymer, polyurethane, chlorinated polyethylene, chlorinated polypropylene Etc. These may be used alone or in combination of two or more.

  The polymerization method of the vinyl chloride resin is not particularly limited, and any conventionally known polymerization method can be used. Examples thereof include a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, and a suspension polymerization method.

When the degree of polymerization of the vinyl chloride resin decreases, the mechanical properties tend to decrease, and when it increases, the moldability tends to deteriorate. Therefore, it is preferably about 400 to 2500, more preferably about 600 to 2000, 600 to It is about 1600.
Examples of the method for adjusting the degree of polymerization mainly include the polymerization temperature. In general, the higher the polymerization temperature, the lower the degree of polymerization. The degree of polymerization can be measured according to JIS K 6720-2.

  In the vinyl chloride resin composition of the present invention, 3 to 50 parts by weight of the vinyl chloride hollow particles described above are added to 100 parts by weight of the vinyl chloride resin (hereinafter sometimes referred to as “PVC”). It is suitable to mix. By setting it as this range, the resin composition can be sufficiently reduced in weight, and damage to the appearance of a molded product produced using the resin composition can be prevented. However, as long as the appearance of the molded product is not important, it may be used in excess of 50 parts by weight.

The vinyl chloride resin composition of the present invention preferably further contains an impact modifier and an acrylic processing aid having a weight average molecular weight of 1,000,000 to 6,000,000.
The amount of these used is, for example, 1 to 30 parts by weight of an acrylic processing aid having an impact modifier of 1 to 30 parts by weight and a weight average molecular weight of 1 to 6 millions per 100 parts by weight of the vinyl chloride resin. Is suitable.

  This vinyl chloride resin composition does not impair the purpose of the present invention, particularly when a molded product is produced, and further, stabilizers, fillers, lubricants, ultraviolet absorbers, pigments and the like that are usually blended in PVC. You may mix | blend in the range.

The vinyl chloride resin composition includes the above-described vinyl chloride resin, impact modifier, acrylic processing aid having a weight average molecular weight of 1,000,000 to 6 million, optionally stabilizer, filler, lubricant, ultraviolet absorber, The pigment or the like is charged into a known mixing apparatus such as a ribbon blender, a V-type blender, or a Henschel mixer (trademark) and mixed.
When mixing the vinyl chloride resin composition using a mixing device, it may be heated, but the vinyl chloride hollow particles are added after the heating and mixing in the case where the above components are added and heated / mixed. Or it is preferable to add and stir when it becomes about 80 degrees C or less at the time of cooling. This is to prevent deformation or damage of the air gap due to heating.
Further, kneading granulation may be performed using a known granulating apparatus. Examples of the granulator include a single screw or twin screw extruder. You may pelletize from a roll processing sheet.
When a vinyl chloride resin composition is granulated using a granulator, it may be heated, but vinyl chloride hollow particles may be added and granulated at a resin temperature of 170 ° C. or lower. preferable.

<Manufacture of molded products>
The molded body of the present invention is not particularly limited, and can have various uses and shapes such as plates or corrugated plates, pipes, pipe joints, sheets, films, and the like.
Such a molded body can be manufactured by normal PVC molding. For example, it can be formed into an arbitrary shape using a single-shaft type or biaxial type extruder, screw or the like.
Thus, by forming a molded body from the vinyl chloride resin composition containing the vinyl chloride hollow particles of the present invention, a vinyl chloride molded body having a very low specific gravity and a weight that has never been obtained is obtained. be able to. Further, the maximum flame retardancy can be expected while maintaining the original characteristics and weight reduction of vinyl chloride.

  Hereinafter, the vinyl chloride hollow particles, the production method thereof, the vinyl chloride resin composition and the molded product of the present invention will be described in detail with reference to examples.

Example A: Production of vinyl chloride-based hollow particles (A1) As shown in Table 1, 7.25 kg of ion-exchanged water, trimethylolpropane di (meth) were added to a jacketed 25 liter pressure-resistant polymerizer equipped with a stirrer. 1.1 kg of acrylate, 3.7 g of disecbutyl peroxydicarbonate and 5.5 g of α-cumylperoxyneodecanoate as an oil-soluble radical initiator, 1712 g of colloidal silica at a concentration of 20% as a dispersant, and a concentration of 30% polyvinyl A solution in which 30.1 g of pyrrolidone, 2790 g of sodium chloride and 10.9 g of hydrochloric acid were mixed was prepared. The obtained monomer solution was added to dissolved water and stirred for 10 minutes using a stirring and dispersing device to obtain a suspension.

  After sealing the polymerization vessel and excluding air, 2.6 kg of vinyl chloride monomer was injected, and after stirring for 10 minutes, the temperature was raised to 54 ° C. (degree of polymerization 1300) while stirring. Was suspended in water while maintaining at 54 ° C. (degree of polymerization 1300). After 1.5 hours from the start of polymerization (setting so that the polymerization rate was 60%), the polymerization vessel was cooled by passing cooling water through the jacket. Thereafter, the polymerization slurry was taken out and dehydrated with a dehydrator. Thereafter, it was vacuum dried to remove the vinyl chloride monomer, and at the same time, porous hollow resin particles were obtained. The yield obtained was 2.8 kg, and the yield was 73%.

Example B: Production of vinyl chloride-based hollow particles (A2) 4.4 g of oil-soluble radical initiator α-cumylperoxyneodecanoate, 4.1 kg of vinyl chloride monomer, 2 hours after the start of polymerization (polymerization rate 70%) This was carried out in the same manner as (A1) except that after the elapse of time, the polymerization vessel was cooled by passing cooling water through the jacket. The yield obtained was 3.8 kg, and the yield was 73%.

Example C: Production of vinyl chloride hollow particles (A3) 8.78 kg of ion-exchanged water and, as a dispersant, only 558 g of polyvinyl alcohol having a concentration of 10% was mixed, a solution was prepared, and 1.0 hour after the start of polymerization ( (Setting was made so that the polymerization rate was 35%) After the elapse of time, it was carried out in the same manner as (A1) except that the polymerization vessel was cooled by passing cooling water through the jacket. The yield obtained was 1.3 kg, and the yield was 35.5%.

Example D: Production of vinyl chloride hollow particles (A4) Ion-exchanged water 8.78 kg, trimethylolpropane di (meth) acrylate 0.56 kg, using only 558 g of 10% concentration polyvinyl alcohol as a dispersant, vinyl chloride monomer The procedure was the same as (A1) except that the polymerization vessel was cooled by passing cooling water through the jacket after 3.16 kg and 1.0 hour after the start of polymerization (set so that the polymerization rate was 20%). The yield obtained was 0.9 kg, and the yield was 23.9%.

Example E: Production of vinyl chloride hollow particles (A5) Ion exchange water 8.78 kg, trimethylolpropane di (meth) acrylate 0.56 kg, using only 558 g of 10% polyvinyl alcohol as a dispersant, vinyl chloride monomer The procedure was the same as (A1), except that 3.16 kg and 3.0 hours after the start of polymerization (set to a polymerization rate of 65%) had elapsed, the polymerization vessel was cooled by passing cooling water through the jacket. The yield obtained was 2.4 kg, and the yield was 65.0%.

Reference Example F: Production of Vinyl Chloride-Based Hollow Particles (A6) 8.78 kg of ion exchange water, 0.19 kg of trimethylolpropane di (meth) acrylate, and using only 558 g of 10% polyvinyl alcohol as a dispersant, vinyl chloride monomer The procedure was the same as (A1) except that the polymerization vessel was cooled by passing cooling water through the jacket after 3.16 kg and 1.0 hour after the start of polymerization (set so that the polymerization rate was 10%). The yield obtained was 0.4 kg, and the yield was 10.0%.

Reference example G: Production of vinyl chloride hollow particles (A7) 8.78 kg of ion exchange water, 0.19 kg of trimethylolpropane di (meth) acrylate, and 558 g of polyvinyl alcohol having a concentration of 10% as a dispersant, vinyl chloride monomer The procedure was the same as (A1), except that 3.16 kg and 3.0 hours after the start of polymerization (set to a polymerization rate of 65%) had elapsed, the polymerization vessel was cooled by passing cooling water through the jacket. The yield obtained was 1.9 kg, and the yield was 51.1%.

Comparative Example: Production of Vinyl Chloride (B1) As shown in Table 1, 8.56 kg of ion-exchanged water and disecbutylperoxy as an oil-soluble radical initiator were added to a 25-liter jacketed pressure-resistant polymerizer equipped with a stirrer. A solution was prepared by mixing 1.9 g of dicarbonate, 2.9 g of α-cumylperoxyneodecanoate, and 126 g of polyvinyl alcohol having a concentration of 3% as a dispersant. The obtained monomer solution was added to dissolved water and stirred for 10 minutes using a stirring and dispersing device to obtain a suspension. After sealing the polymerization vessel and excluding air, 4.21 kg of vinyl chloride monomer was injected, and after stirring for 10 minutes, the temperature was raised to 57.5 ° C. (degree of polymerization 1000) while stirring. Water suspension polymerization was carried out while maintaining the temperature at 57.5 ° C. (degree of polymerization 1000). After 5 hours from the start of polymerization (polymerization rate of 85% or more), the polymerization vessel was cooled by passing cooling water through the jacket. Thereafter, the polymerization slurry was taken out and dehydrated with a dehydrator to obtain polyvinyl chloride resin particles. The yield obtained was 3.45 kg, and the yield was 82%.

(Measurement of polymerization rate)
The polymerization rates in Examples A to E, Reference Examples F and G, and Comparative Examples were expressed based on the results of performing polymerization in advance and determining the relationship between the polymerization time and the polymerization rate.
That is, a predetermined amount of deionized water, a predetermined type and amount of dispersant, a predetermined type and amount of an oil-soluble radical initiator, and a predetermined amount of polyfunctional monomer are charged into a stainless polymerizer having an internal volume of 2 m ^3. Thereafter, deaeration was performed until the internal pressure of the polymerization vessel reached 8 kPa · abs (60 mmHg), and a predetermined amount of vinyl chloride monomer was charged. Thereafter, a predetermined type and amount of a polymerization initiator were charged while stirring, and the temperature was raised at the same time. When the temperature in the polymerization vessel reached 57.0 ° C., the temperature was maintained and polymerization was continued. Cooling was started 1 hour after the start of temperature increase, polymerization was completely stopped, and unreacted monomers were recovered. The total amount of the vinyl chloride polymer obtained by dehydrating and drying the polymer slurry was weighed, and the polymerization rate after 1 hour from the start of temperature increase was determined by the following formula.
Polymerization rate (%) 1 hour after the start of temperature increase = (Amount of vinyl chloride polymer after drying / Amount of charged polyfunctional monomer and vinyl chloride monomer) × 100
Similarly, after the start of temperature increase, the polymerization rate was calculated for each of 30 minutes after 1.5, 2, 2.5, 3, 3.5, 4, 4.5 and 5 hours, The relationship between time and polymerization rate was determined. The relationship between the polymerization time and the polymerization rate was prepared for each required type and amount of polymerization initiator and a predetermined polymerization temperature.

(Measurement of porosity)
About the obtained vinyl chloride type | system | group hollow particle, the hollow part volume which occupies in the whole volume of a hollow particle was measured. The measurement was performed using an AMCO Porosimeter 2000 under the condition of enclosed mercury pressure of 2000 kg / cm ² . The results are shown in Table 2 in percentage (%).

表２中の塩化ビニルの割合は、全モノマー成分（塩化ビニル＋多官能性モノマー）との合計重量）に対する重量％である。

The ratio of vinyl chloride in Table 2 is% by weight based on the total weight of all monomer components (vinyl chloride + polyfunctional monomer).

Examples and Comparative Examples: Preparation of Vinyl Chloride Resin Compositions With respect to 100 parts by weight of vinyl chloride resin (trade name “TS800E”, manufactured by Tokuyama Sekisui Industry Co., Ltd.), an organic tin stabilizer (octyl tin mercapto) as a heat stabilizer , 2.0 parts by weight of a trade name “TVS # 1380” manufactured by Nitto Kasei Kogyo Co., Ltd. and 2.0 parts by weight of a trade name “Wax-OP” (manufactured by Hoechst) as a lubricant The predetermined vinyl chloride-based hollow particles obtained in Examples A and B shown in Table 2 were stirred and mixed to obtain a vinyl chloride-based resin composition.
The obtained vinyl chloride resin composition was kneaded with an 8-inch roll molding machine at 190 ° C. for 3 minutes to obtain a sheet having a thickness of 1.5 mm, and a molded article made of the vinyl chloride resin composition was obtained.

(Measurement of specific gravity)
A 40 × 50 mm test piece was cut out from the molded sample piece, and the specific gravity was measured according to JISK7112. The results are shown in Table 3.

表３の結果から、本発明によれば、高い空隙率と強度とを両立した中空塩ビ粒子とその成形体を得ることができることが確認された。

From the results in Table 3, it was confirmed that according to the present invention, hollow PVC particles and a molded body thereof having both high porosity and strength can be obtained.

  The vinyl chloride hollow particles, the production method thereof, the vinyl chloride resin composition and the vinyl chloride molded article of the present invention can be used as an alternative in all of the conventionally used vinyl chloride resin compositions and molded articles. Applications in new fields where weight reduction and functionalization are required, such as building materials and interiors of vehicles, are expected.

Claims (6)

(1) A monomer component containing vinyl chloride as a main component and a polyfunctional monomer, a polymerization initiator and a dispersant are mixed in a polar medium to prepare a suspension,
(2) The suspension is heated to polymerize the monomer component, and when the polymerization rate of the monomer component is 75% or less, unreacted vinyl chloride is removed to form resin particles,
(3) including a step of dehydrating and drying the resin particles;
A method for producing vinyl chloride hollow particles, wherein the polyfunctional monomer is 15.0% by weight or more of the total monomer components.   The method for producing vinyl chloride hollow particles according to claim 1, wherein the vinyl chloride is 70% by weight or more of the total monomer components. It is obtained by suspension polymerization in a system containing a monomer component containing vinyl chloride as a main component and a polyfunctional monomer, a polymerization initiator, and a dispersant,
The polyfunctional monomer is 15.0% by weight or more of the total monomer components;
A vinyl chloride hollow particle having a porosity of 25% or more and less than 75%.   The vinyl chloride hollow particles according to claim 3, wherein the vinyl chloride is 70% by weight or more of the total monomer components. A vinyl chloride resin composition comprising at least the vinyl chloride hollow particles according to claim 3 or 4, and a vinyl chloride resin,
A vinyl chloride resin composition comprising 3 to 50 parts by weight of the hollow particles with respect to 100 parts by weight of the vinyl chloride resin. A vinyl chloride-based molded article formed by the vinyl chloride-based resin composition according to claim 5.