JPH09202842A - Aqueous dispersion of vinyl chloride-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject dispersion capable of giving a vinyl chloride- based polymer for paste which, in turn, is capable of giving a low-viscosity plastisol of good gellability, to provide a method for producing the dispersion, to obtain the vinyl chloridebased polymer, and to obtain gloves by using this polymer. SOLUTION: This aqueous dispersion is obtained by seeding emulsion polymerization or seeding fine suspension polymerization of a vinyl chloride-based monomer in the presence of a seed polymer. The particle size distribution representing the relationship between particle diameter and the proportion of the polymer particles having this diameter per the total particles (wt.%) has the following characteristics: (a) the graph representing the particle size distribution has only one maximum value; (b) the particle diameter corresponding to the maximum value in (a) is 0.8-1.8μm; (c) at least 98wt.% of the polymer particles in the aqueous dispersion has a diameter of 0.08-2μm; (d) 65-87wt.% of the polymer particles in the aqueous dispersion has a diameter of 0.5-2μm; and (e) 11-33wt.% of the polymer particles in the aqueous dispersion has a diameter of 0.08-0.5μm.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aqueous dispersion of a vinyl chloride polymer, a vinyl chloride polymer and a method for producing the dispersion, which is capable of obtaining a plastisol having a low viscosity and a good gelling property. The present invention relates to a glove manufactured using the vinyl chloride polymer.

[0002]

2. Description of the Related Art Generally, a vinyl chloride polymer for a paste is a water-soluble vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable therewith (hereinafter referred to as "vinyl chloride monomer"). After emulsion polymerization using a polymerization initiator, or mechanically homogenizing the vinyl chloride monomer beforehand and dispersing it in water, a polymerization initiator soluble in the vinyl chloride monomer (hereinafter It is produced by fine suspension polymerization using an "oil-soluble polymerization initiator"). Further, a so-called seeding polymerization method, in which a seed polymer is used in the above two polymerization methods, is often used because it is easy to control the particle diameter of the produced polymer particles and has good productivity.

As an improved method of this seeding polymerization method, seeding emulsion polymerization is carried out using a vinyl chloride polymer produced by a fine suspension polymerization method as a seed polymer, whereby a low viscosity and a good gelling property are obtained. A method for producing a vinyl chloride-based polymer for paste which can give plastisol has been proposed (JP-A-5-2731313). However, in this method, since the reaction is carried out in the presence of a large amount of the polymerization initiator during seeding polymerization, the polymerization initiator may be rapidly decomposed in some cases. There is a drawback that it is difficult to control the particle size of the polymer particles.

Therefore, as a method for improving the reaction controllability of the seeded emulsion polymerization method as described above, a fine suspension polymerization of a vinyl chloride monomer using an oil-soluble polymerization initiator is carried out, and the polymerization obtained here is carried out. After adding a water-soluble reducing agent to the aqueous dispersion of the polymer particles containing the remaining initiator, after heat treatment to substantially decompose and remove the polymerization initiator, use the polymer particles as a seed polymer A method of carrying out seeding emulsion polymerization has been proposed (JP-A-6-279510). However, this method has a problem that the polymer may be deteriorated by heating when decomposing the initiator, and if the treatment is carried out at a relatively low temperature in order to avoid this, it takes a long time.

Further, a method of carrying out seeding polymerization using a plurality of seed polymers having different average particle diameters has been proposed, but the operations required for preparation and mixing of the seed polymer are complicated, and in this way. It was difficult to say that the viscosity and gelation property of the plastisol based on the polymer obtained as described above were sufficient.

[0006]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide an aqueous dispersion of a vinyl chloride polymer and a vinyl chloride polymer which have a low viscosity and good viscosity stability and can give a plastisol having a fast gelation. It is an object of the present invention to provide a coalesced body and a method for producing the dispersion by a seeding polymerization method with good reaction controllability, and a glove produced using the vinyl chloride polymer.

[0007]

Means for Solving the Problems As a result of extensive studies conducted by the present inventors in order to achieve the above object, the plastisol of a vinyl chloride polymer obtained by seed polymerization has insufficient viscosity and gelation property. The cause is that the distribution of the particle size of the polymer, that is, the ratio of relatively large particle size particles obtained by seed polymer growth during seeding polymerization, and newly generated relatively small particle size particles Is not appropriate, and in the case of using a plurality of seed polymers having different average particle diameters, it is based on that the particle diameter distribution in the aqueous dispersion obtained by growing each polymer by seeding polymerization is not appropriate. It was found that, based on this finding, further intensive investigations revealed that a polymer having a specific particle size distribution in an aqueous dispersion can give a plastisol having low viscosity and good gelation property. You see And we have completed the present invention. Further, the present inventors have found that plastisol having a specific particle size distribution is
The present invention has been completed by finding out that it has a low viscosity and a good gelling property.

That is, the gist of the present invention is an aqueous dispersion of a vinyl chloride polymer obtained by seeding emulsion polymerization or seeding fine suspension polymerization of a vinyl chloride monomer in the presence of a seed polymer. Then, the particle size distribution (hereinafter abbreviated as “particle size distribution”) showing the relationship between the particle size and the weight ratio (%) of the polymer particles of the particle size in all particles is as follows (a) to ( A vinyl chloride polymer aqueous dispersion having the characteristics of d).

(A) The particle size distribution graph is 0.08-2.
It is a distribution (single peak distribution) having only one maximum in the μm range. (B) The particle size that gives the maximum value in (a) (hereinafter,
It is described as "peak particle size" and represented by "Dp") is 0.8 to
Within the range of 1.8 μm. (C) 98% by weight or more of the polymer particles in the aqueous dispersion are in the range of 0.08 to 2 μm in particle size.

(D) 65 to 65 of polymer particles in the aqueous dispersion.
87% by weight is in the range of particle size 0.5-2 μm. (E) 11 to 33% by weight of the polymer particles in the aqueous dispersion is in the range of particle diameter 0.08 to 0.5 μm.

Further, the gist of the present invention is that the particle size is such that the cumulative value of the weight ratio of the polymer particles in the aqueous dispersion reaches 50% by weight (hereinafter referred to as "median size", "D").
m ”), and the ratio (Dp / Dm) of the peak particle size to 1.05 to 1.4.

A vinyl chloride polymer having a median diameter of 0.4 to 0.9 μm and a Dp / Dm of 0.7 to 1.8 produced by fine suspension polymerization as a seed polymer. Using a hydrogen chloride as a water-soluble polymerization initiator, the method for producing an aqueous dispersion of a vinyl chloride polymer as described above, wherein the emulsion polymerization is carried out, and the content of an oil-soluble polymerization initiator as a seed polymer at that time In a method using a vinyl chloride polymer whose amount is 0.1 wt% or less relative to the seed polymer,

A method of producing the aqueous dispersion using a sulfuric acid ester salt of polyoxyethylene alkyl ether as an emulsifier in seed emulsion polymerization, further comprises seeding emulsifying a vinyl chloride monomer in the presence of a seed polymer. A vinyl chloride polymer obtained by polymerization or seeding fine suspension polymerization, the particle size of the polymer particles in the plastisol prepared by using the vinyl chloride polymer, and the polymer particles having the particle size. The particle size distribution, which represents the relationship with the weight ratio (%) in all particles, is present in the vinyl chloride polymer having the following characteristics (f) to (j):

(F) The particle size distribution graph is 0.08-2.
It is a distribution (single peak distribution) having only one maximum in the μm range. (G) The particle diameter that gives the maximum value in (f) (hereinafter,
"Peak particle size", expressed as "Dp '") is 0.8 to
Within the range of 1.8 μm. (H) 98% by weight or more of the polymer particles in the plastisol are in the range of particle diameter 0.08 to 2 μm. (I) 65-87% by weight of polymer particles in plastisol
Is in the range of 0.5 to 2 μm. (J) 11-33% by weight of polymer particles in plastisol
Is in the range of 0.08 to 0.5 μm.

Further, in the above particle size distribution, the peak particle size with respect to the particle size (hereinafter referred to as "median size", represented by "Dm '") at which the cumulative value of the weight ratio of the polymer particles in the plastisol reaches 50% by weight. Ratio (Dp '/ Dm') is 1.0
It also exists in vinyl chloride polymers of 5 to 1.4, and also in gloves manufactured using the above vinyl chloride polymers.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the vinyl chloride polymer aqueous dispersion of the present invention and the method for producing the same will be specifically described. In the present invention, unless otherwise specified, the “polymer particles” mean vinyl chloride polymer particles. The aqueous vinyl chloride polymer dispersion of the present invention is characterized by having the following specific particle size distribution. That is, (a) the particle size distribution graph is a distribution (single peak distribution) having only one maximum value in the range of 0.08 to 2 μm. (B) The particle diameter (peak particle diameter, Dp) that gives the maximum value in (a) is in the range of 0.8 to 1.8 μm.

(C) 98% by weight or more of the polymer particles in the aqueous dispersion is in the range of 0.08 to 2 μm in particle size. (D) 65 to 87% by weight of the polymer particles in the aqueous dispersion is in the range of 0.5 to 2 μm in particle size. (E) 11 to 33% by weight of the polymer particles in the aqueous dispersion is in the range of particle diameter 0.08 to 0.5 μm. , Is.

When the above conditions are not satisfied, for example, when the particle size distribution becomes a double peak distribution in the above range, gelation tends to be slow, and when Dp is less than 0.8 μm, the viscosity of plastisol increases and If the stability of viscosity with time is lowered, and if Dp becomes larger as it exceeds 1.8 μm, the gelation property tends to deteriorate. In the present invention, the plastisol refers to a sol-like dispersion liquid in which a vinyl chloride polymer is dispersed in a plasticizer, and a plastisol in which a vinyl chloride polymer is dispersed in an organic solvent or the like is called an organosol.

The distribution of the polymer particles in the vinyl chloride polymer aqueous dispersion of the present invention is such that 98% by weight or more of all the polymer particles are in the range of 0.08 to 2 μm in particle size, and the range is also within the range. Of the polymer particles having a particle diameter of 0.5 to 2 μm with respect to the total amount of polymer particles in the aqueous dispersion (hereinafter referred to as “L
% ") Is 65 to 87% by weight, and 0.08 to
Ratio of polymer particles of 0.5 μm (hereinafter referred to as “S%”)
Is 11 to 33% by weight.

When L% is less than 65% by weight or S% exceeds 33% by weight, the plastisol viscosity is high, the viscosity stability is lowered, and the gelation rate is not improved, which is not preferable. On the other hand, when L% exceeds 87% by weight or S% is less than 11% by weight, the viscosity of the obtained plastisol in the high shear region remarkably increases, which is also not preferable.

Further, when the ratio (Dp / Dm) of the peak particle diameter (Dp) to the median diameter (Dm) is out of the range of 1.05 to 1.4, the gelling property generally tends to deteriorate. Become. Figure 1 shows an example of a graph of particle size distribution.

The aqueous vinyl chloride polymer dispersion of the present invention can be produced as follows. Examples of the vinyl chloride-based monomer used as a raw material for the aqueous dispersion of the vinyl chloride-based polymer include vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable therewith. Examples of monomers copolymerizable with vinyl chloride include olefins such as ethylene, propylene and n-butene; vinyl esters such as vinyl acetate, vinyl propionate and vinyl stearate; acrylic acid, methacrylic acid and itaconic acid. Unsaturated carboxylic acids such as or their alkyl esters such as methyl ester and ethyl ester; methyl vinyl ether,
Vinyl ethers such as octyl vinyl ether and lauryl vinyl ether; unsaturated divalent carboxylic acids such as maleic acid and fumaric acid or (di) alkyl esters thereof such as dimethyl ester and diethyl ester; unsaturated nitriles and the like. One or a mixture of two or more compounds can be used. The amount of the monomer copolymerizable with the vinyl chloride is preferably 30% by weight or less, more preferably 20% by weight or less, based on the total amount of vinyl chloride-based monomers.

The vinyl chloride polymer aqueous dispersion of the present invention can be produced by seeding emulsion polymerization or seeding fine suspension polymerization of the above vinyl chloride monomer in the presence of a seed polymer. In particular, the seed emulsion polymerization method is preferable because the controllability of the particle size is good. As the seed polymer, it is preferable to use a polymer obtained by carrying out fine suspension polymerization using an oil-soluble polymerization initiator in order to obtain the above specific particle size distribution.

The seed polymer is obtained by adding a vinyl chloride monomer to water,
It can be produced by mixing with an oil-soluble polymerization initiator and an emulsifier, performing homogenization treatment using an emulsifying machine (homogenizer), dispersing in the form of fine droplets, and then performing fine suspension polymerization. As the emulsifier, for example, a colloid mill, a high speed pump, a Manton-Gaulin type high-pressure homogenizer, a pipeline mixer, an ultrasonic disperser, a vibration stirrer or the like can be used. Of these, the Manton-Gaulin high-pressure homogenizer is particularly preferable because the dispersed droplet diameter can be adjusted by selecting the emulsifying pressure.

The emulsifier used in the production of the seed polymer is not particularly limited, and examples thereof include alkali metal salts and ammonium salts of higher alcohol sulfuric acid esters such as sodium lauryl sulfate, and alkylbenzenes such as sodium dodecylbenzenesulfonate. Sulfonic acid (preferably alkyl group having 6 to 18 carbon atoms) alkali metal salt and ammonium salt, polyoxyethylene alkyl ether sulfonic acid (preferably alkyl group having 3 carbon atoms)
To 18, particularly preferably 6 to 12) alkali metal salts and ammonium salts, higher fatty acid alkali metal salts and ammonium salts, and sulfosuccinic acid dialkyl esters (preferably having an alkyl group with 4 to 12 carbon atoms, particularly preferably 8). Anionic surfactants such as alkali metal salts of
Polyoxyethylene alkyl ether (preferably an alkyl group having 3 to 18 carbon atoms, particularly preferably 6 to 1)
2), one or a mixture of two or more nonionic surfactants such as polyoxyethylene alkylphenyl ether (preferably having an alkyl group having 3 to 12 carbon atoms), sorbitan fatty acid ester, and polyoxyethylene higher fatty acid ester. Is used. The emulsifier is preferably used in an amount of 0.1 to 3% by weight, and more preferably 0.3 to 1% by weight, based on the vinyl chloride-based monomer.

Further, as an emulsification aid, a carbon number of 10-18
Higher alcohol of 0.2 to vinyl chloride-based monomer
You may use together 2 weight%. As the oil-soluble polymerization initiator used for the production of the seed polymer, one that has high stability against these physical forces so that decomposition does not occur due to heat generation and impact (due to the stirring blade of the homogenizer) during homogenization treatment. It is suitable. For example, lauroyl peroxide, t-
Organic peroxides such as butylperoxypivalate, azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, and azo compounds can be used.

It is preferable to use these oil-soluble polymerization initiators in an amount of 0.1 to 0.4% by weight, preferably 0.15 to 0.3% by weight, based on the vinyl chloride monomer. . If the amount of the initiator is less than 0.1% by weight, the conversion rate of the monomer is extremely low and the polymerization reaction requires a long time, which is not preferable. On the other hand, if the amount exceeds 0.4% by weight, the content tends to deviate significantly from the content of the polymerization initiator in the seed polymer, which is suitable for seed polymerization.

Regarding the particle size distribution of the seed polymer, most of it (95% by weight or more) is in the range of 0.08 to 2 μm, and its median diameter (Dm) is 0.4 to 0.9 μm.
And the ratio of the peak particle diameter (Dp) to the median diameter is 0.7 to 1.8. When this ratio is less than 0.7, the distribution of the polymer particles on the large particle size side of the polymer aqueous dispersion after seeding polymerization becomes wide,
It is not preferable because it becomes difficult to obtain an aqueous polymer dispersion having the particle size distribution of the present invention. If this ratio exceeds 1.8, the peak particle size of the resulting polymer aqueous dispersion becomes large, and it becomes difficult to obtain an aqueous dispersion having the particle size distribution of the present invention, and the specific surface area becomes small. It is not preferable because the absorbability of the plasticizer is deteriorated and the gelation is delayed.

The content of the oil-soluble polymerization initiator in the seed polymer particles is preferably 0.1% by weight or less based on the seed polymer. When the residual amount exceeds 0.1% by weight, the seeding polymerization rate is increased, the reaction controllability is deteriorated, and new particles are often generated, which makes it difficult to obtain an aqueous dispersion having a desired particle size distribution. . The amount of the polymerization initiator in the seed polymer particles can be measured, for example, by GPC (gel permeation chromatography) by a calibration curve method.

At this time, if the seed polymer is produced under the above-mentioned conditions, it is not usually necessary because the amount of the oil-soluble polymerization initiator used is small, but the oil-soluble polymerization initiation remaining in the seed polymer particles is not necessary. If the amount of the agent is large, perform the decomposition treatment,
The content of the oil-soluble polymerization initiator may be 0.1% by weight or less based on the seed polymer. Examples of the heat treatment method at this time include a method in which a predetermined amount of water and a seed polymer are added as they are or after degassing, a water-soluble reducing agent is added, and the mixture is heated in the absence of a vinyl chloride monomer. Can be adopted. It is necessary that the temperature of the heat treatment is such that the stability of the aqueous dispersion of the seed polymer is not impaired, and the temperature is 40 to 70 ° C.
Is preferably in the range of 50 to 60 ° C. The treatment time is about 6 to 24 hours depending on the temperature of the heat treatment.

As the water-soluble reducing agent used in the heat treatment,
For example, water-soluble inorganic reducing agents such as sodium sulfite, sodium hydrogen sulfite, ammonium sulfite, sodium pyrosulfite, and ascorbic acid or a metal salt thereof, water-soluble organic reducing agents such as sodium formaldehyde sulfoxylate are particularly limited. Can be used without The reducing agent is usually used in a stoichiometric amount or more with respect to the oil-soluble polymerization initiator contained in the seed polymer particles. This treatment can be carried out by providing a treatment facility separate from the polymerization system, or carried out in a polymerization vessel in which seed polymerization is carried out, and the treated polymer particles are directly used as a seed polymer in the same reactor. Seeding polymerization may be subsequently carried out.

The polymerization time of fine suspension polymerization for producing a seed polymer is usually about 6 to 12 hours, and the solid content concentration of the aqueous dispersion obtained here is about 25 to 45% by weight. The aqueous dispersion after polymerization is used as it is as a seed polymer for seed polymerization without drying. Seed polymerization can be started by using the above-mentioned polymer particles as a seed polymer, introducing a vinyl chloride-based monomer into the system, heating the temperature, and adding a water-soluble polymerization initiator. Before introducing the monomer, water, an emulsifier, a reducing agent, or other auxiliary agents can be added or added as needed.

The amount of the seed polymer used in the seed polymerization is usually 3 to 30% by weight, preferably 5 to 15% by weight, based on the total amount of the solid content of the seed polymer and the vinyl chloride monomer. is there. When the amount of the seed polymer used is less than 3% by weight, the controllability of the particle size distribution of the resulting polymer aqueous dispersion is deteriorated, while when it exceeds 30% by weight, the amount of the oil-soluble polymerization initiator in the system is increased. However, the reaction controllability may be deteriorated, which is not preferable.

The emulsion polymerization method is preferably used as the seed polymerization in terms of both controllability of reaction and controllability of particle size distribution. Hydrogen peroxide is used as a water-soluble polymerization initiator as a polymerization initiator for seed emulsion polymerization. Hydrogen peroxide may be used in combination with a water-soluble peroxide such as persulfate such as sodium persulfate or ammonium persulfate, but the mixing ratio of hydrogen peroxide should be 50 mol% or more of the whole. To do. A peroxide such as hydrogen peroxide may be used as a redox initiator in combination with the aforementioned water-soluble reducing agent. By using hydrogen peroxide as a polymerization initiator, generation of new polymer particles during seeded emulsion polymerization can be suppressed. The water-soluble polymerization initiator is 0.01 to 0.05% by weight with respect to the vinyl chloride-based monomer, preferably 0.02 to
It is advisable to use 0.04% by weight.

As the emulsifier used in the seed emulsion polymerization, one or a mixture of two or more of various anionic surfactants or nonionic surfactants exemplified in the description of the above-mentioned seed polymer production is used. Can be used. This emulsifier is the same as the emulsifier used to produce the seed polymer,
They may be different, but among them, polyoxyethylene alkyl ether (preferably an alkyl group having 3 to 1 carbon atoms).
The sulfuric acid ester salt of No. 8, particularly preferably 6 to 12) does not generate new polymer particles and prevents aggregation of the polymer particles even if the addition amount is small, and the mechanical and aqueous properties of the polymer aqueous dispersion are improved. It is preferable because thermal stability can be maintained. The amount of these emulsifiers used is 0.
It is 3 to 3% by weight, preferably 0.4 to 1% by weight.

The water-soluble polymerization initiator and the emulsifier used in the seed emulsion polymerization are preferably added continuously during the seed emulsion polymerization in order to control the generation of new particles.
The polymerization time of the seeded emulsion polymerization is usually about 6 to 10 hours. Further, the solid content concentration in the vinyl chloride polymer aqueous dispersion obtained here is often about 37 to 45% by weight.

The vinyl chloride polymer aqueous dispersion obtained as described above is subjected to commercialization treatment such as drying and pulverization by a known method to produce a vinyl chloride polymer. In the process of commercialization, various commonly used adjusting emulsifiers, antioxidants, other auxiliaries, modifiers and the like can be added. As a method for drying the aqueous dispersion, for example, a usual spray dryer used for producing a vinyl chloride polymer for paste can be used. As the spraying method, for example, a method using a rotating disk, a pressure nozzle, a two-fluid nozzle or the like can be exemplified. The temperature at the time of spray drying is usually 100 at the inlet of the drying device for the drying air flow.
˜200 ° C. and the outlet temperature is in the range of 45˜80 ° C.

Further, the vinyl chloride polymer of the present invention is characterized in that the polymer particles in the plastisol prepared by using the vinyl chloride polymer have the following specific particle size distribution. That is, (f) the particle size distribution graph is a distribution (single peak distribution) having only one maximum value in the range of 0.08 to 2 μm. (G) The particle diameter that gives the maximum value in (f) (hereinafter,
"Peak particle size", expressed as "Dp '") is 0.8 to
Within the range of 1.8 μm. (H) 98% by weight or more of the polymer particles in the plastisol are in the range of particle diameter 0.08 to 2 μm. (I) 65-87% by weight of polymer particles in plastisol
Is in the range of 0.5 to 2 μm. (J) 11-33% by weight of polymer particles in plastisol
Is in the range of 0.08 to 0.5 μm.

When the above conditions are not satisfied, for example, when the particle size distribution becomes a two-peak distribution in the above range, gelation tends to be slow, and when Dp 'is less than 0.8 μm, the plastisol viscosity increases. At the same time, the stability of viscosity with time decreases, and when Dp ′ increases to more than 1.8 μm, the gelation property tends to deteriorate.

Further, in the vinyl chloride polymer of the present invention, the distribution of the polymer particles in the plastisol is 9% of all the polymer particles.
8% by weight or more is in the range of particle size 0.08-2 μm,
Within this range, the ratio of polymer particles having a particle diameter of 0.5 to 2 μm to the total amount of polymer particles in the plastisol (hereinafter referred to as “L ′%”) is 65 to 87% by weight,
Ratio of polymer particles of 08 to 0.5 μm (hereinafter “S ′%”
Is described) is 11 to 33% by weight.

L '% is less than 65% by weight, S'
% Of more than 33% by weight is not preferable because the plastisol viscosity is high, the viscosity stability is lowered, and the gelation rate is not improved. On the other hand, when L '% exceeds 87% by weight or S'% is less than 11% by weight, the viscosity of the obtained plastisol in the high shear region remarkably increases, which is also not preferable.

The ratio (Dp '/ Dm') of the peak particle diameter (Dp ') to the median diameter (Dm') is 1.05.
When it is out of the range of 1.4, the gelation property generally tends to deteriorate.

A plastisol or an organosol can be obtained by adding a plasticizer, an organic solvent, a stabilizer and the like to the vinyl chloride polymer and mixing the mixture using a mixer such as a Hobart mixer, a chemi-stirrer, a triple roll or a ribbon blender. You can The plasticizer used here is not particularly limited as long as it is usually used as a plasticizer for vinyl chloride polymers, and examples thereof include di-2-ethylhexyl phthalate (DOP) and diisononyl phthalate (DINP). Phthalic acid plasticizers, dimethyl isophthalate, diethyl isophthalate, isophthalic acid plasticizers such as di-2-ethylhexyl isophthalate, tri-2-ethylhexyl trimellitate, trimellitic acid plasticizers such as triisodecyl trimellitate, adipine Acid 2-ethylhexyl acid, dibutyl sebacate and other fatty acid ester plasticizers, tributyl phosphate, tricresyl phosphate and other phosphoric acid plasticizers, ethylene glycol, 1,3-
Examples thereof include polyester plasticizers obtained by polycondensing polyhydric alcohols such as butanediol and polyvalent carboxylic acids such as phthalic acid and adipic acid. The stabilizer is not particularly limited as long as it is usually used as a stabilizer for vinyl chloride polymers, and examples thereof include tin fatty acid salts, tin compounds such as tin mercaptide, and barium-zinc compound stabilizers. Among them, a barium-zinc type liquid stabilizer is particularly preferable. In addition to the above components, if necessary, a secondary plasticizer, a diluent, an antioxidant, an ultraviolet absorber, an antistatic agent,
Coloring agents, release agents and other compounding agents may be added.
The obtained plastisol or organosol is molded into wallpaper, flooring, gloves, etc. by a molding method such as knife coating, rotary screen, dipping and rotational molding.

[0044]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. "%" In the examples indicates "% by weight". The particle size and particle size distribution and the solid content concentration of the polymer particles in the aqueous dispersions of Examples 1 and 2 and Comparative Examples 1 to 3 and the following Examples and Comparative Examples are as follows (1)
And the values measured by the method (2). Further, the method for obtaining a vinyl chloride-based polymer from the aqueous dispersion (3), the method for measuring the particle size and particle size distribution of the polymer particles of the vinyl chloride-based polymer in plastisol (4), plastisol The evaluation methods are shown in (5) to (7).

(1) Particle Size Distribution and Median Diameter of Polymer Particles in Aqueous Dispersion: The particle size distribution and median diameter of polymer particles in the vinyl chloride polymer aqueous dispersion are those from Horiba, Ltd. Laser Diffraction / Scattering Particle Size Analyzer (L
A-700). The measurement result is shown in FIG.

(2) Solid content concentration: About 1 g of an aqueous dispersion of a vinyl chloride polymer was sampled and precisely weighed (designated as W ₀ ).
Heat in an oven maintained at 105 ° C for 1 hour to evaporate water. Allow to cool for 30 minutes in a desiccator, and weigh accurately again (designated as W ₁ ). The solid content concentration was calculated as W ₁ / W ₀ × 100 (%). (The volatile content measurement method of JIS-K6721 was referred to.)

(3) Spray drying of polymer aqueous dispersion: After filtering the vinyl chloride polymer aqueous dispersion with a 20-mesh wire mesh,
Small spray dryer (SA Niro Atomizer
(Production-Minor type manufactured by Hamamatsu Co., Ltd.) was spray-dried under the conditions of a chamber inlet temperature of 140 ° C. and an outlet temperature of 50 ° C., and then pulverized with a hammer mill (Hosokawa Micron MA-5 type).

(4) Particle size distribution and median diameter of vinyl chloride polymer in plastisol: A vinyl chloride polymer aqueous dispersion was spray-dried and pulverized by the method described in (3) to obtain chloride. 0.1g vinyl polymer and plasticizer (DOP
By putting 2 drops of Mitsubishi Chemical Co., Ltd. Diasizer between two slide glasses, and rubbing for 5 minutes,
Crush. Disperse the obtained droplets in the above plasticizer,
The particle size distribution and median size are measured by the laser diffraction / scattering type particle size distribution measuring device (LA-700) used in (1). The results are shown in Figure 4.

(5) Viscosity: 100 parts by weight of a vinyl chloride polymer and 60 parts by weight of DOP were blended and mixed with a mixer (HOBA).
RT MIXER N-50 type, THE HOBART
MFG. CO. 5 minutes at # 1 speed, # 2
Mix for 15 minutes at speed to obtain plastisol. After leaving this plastisol in a constant temperature and humidity chamber at 23 ° C. and a humidity of 50% for 2 hours, the viscosity was measured with a B8H type viscometer (Brookfield viscometer) manufactured by Tokimec Co., # 6 (or # 7).
The measurement was performed at a rotation speed of 50 rpm using a rotor. ("B
₅₀ ") 1 hour later, a Saver viscometer (Mod
el A120, BURRELL CO. 9)
Outflow under constant pressure of 0 psi (621 kPa) (g / 1
(00 seconds) was measured and used as a measure of the flowability in the high shear region. (Indicated as "S ₉₀ ")

(6) Viscosity stability: The plastisol prepared in (5) and measured for viscosity is stored in a constant temperature and humidity chamber at 23 ° C. and a humidity of 50%, and after 7 days, the viscosity is measured again. The ratio of the viscosity after 7 days to the initial viscosity is defined as AI (Aging Index).
ex) is an index of viscosity stability.

(7) Gelability: Vinyl chloride polymer 100
Part by weight and 70 parts by weight of di-2-ethylhexyl phthalate are mixed and stirred and mixed by using a Chemi stirrer to obtain plastisol. Vacuum degas this plastisol and
Let stand for 2 hours in a constant temperature and humidity room at a temperature of 50 ° C and a humidity of 50%. Collect a certain amount of this plastisol into a glass tube with a diameter of 20 mm,
While heating this in an oil bath at 100 ° C., the viscosity is measured at regular time intervals using a B8R viscometer (using a # 7 rotor) manufactured by Tokimec Co., Ltd. Graph the relationship between viscosity and heating time, and the viscosity value is 160 Pa · s (160
Time (A) to reach 0 poise) and viscosity value is 80 Pa · s
The required time (B) from (800 poise) to 480 Pa · s (4800 poise) was calculated, and the gelling time A and the gelling time B were respectively used as a measure of gelation property.

<Example 1> (Production of oil-soluble polymerization initiator-containing seed polymer aqueous dispersion by fine suspension polymerization method) Stirrer and emulsifier (Manton-Gaulin type high-pressure homogenizer; primary pressure 150 kg / cm ²
G (gauge pressure), a secondary pressure of 50 kg / cm ² G) and a pre-mixing tank of 300 liter capacity equipped with a deionized water of 75 kg, lauroyl peroxide 150 g (0.25% relative to vinyl chloride monomer). ), Sodium lauryl sulfate 558g, lauryl alcohol 400g,
Next, after degassing the preliminary mixing tank, 60 kg of vinyl chloride monomer was added, and the mixture was kept at 35 ° C. while being uniformly stirred. Then, using an emulsifying machine to disperse into fine droplets,
Volume 300 equipped with a stirrer with the dispersion degassed beforehand
Transferred to a liter polymerization tank. After the transfer of the dispersion liquid was completed, the temperature of the polymerization tank was raised to 55 ° C. and the polymerization was started with stirring.
The internal pressure of the polymerization tank is 1.0 kg / cm ² (10
The reaction was stopped when the pressure decreased to 0 kPa), and unreacted monomers were recovered. The reaction time was 8 hours, the solid content concentration of the obtained aqueous dispersion was 32%, the median diameter of the polymer particles in the aqueous dispersion was 0.5 μm, and the ratio of the peak particle diameter to the median diameter was 1. It was 27.

(Decomposition Treatment of Residual Oil-Soluble Polymerization Initiator in Polymer Particles) Subsequently, 80 g of sodium formaldehyde sulfoxylate was charged as a reducing agent while keeping the internal temperature at 55 ° C., and the mixture was heated for 3 hours. The amount of residual lauroyl peroxide in the polymer particles after the treatment was 0.0
It became 5%.

(Seeding emulsion polymerization) Volume 30 equipped with stirrer
In a 0 liter polymerization tank, 74 kg of deionized water, 7 kg of the above treated seed polymer aqueous dispersion (solid content conversion), 15 g of sodium hydrogen carbonate, 15 sodium dihydrogen phosphate.
g, sodium formaldehyde sulfoxylate 55
After charging g, the inside temperature was adjusted to 50 ° C. by degassing. After that, 33 kg of vinyl chloride monomer was charged, the temperature in the polymerization tank was set to 47 ° C., and 0.4% as a water-soluble polymerization initiator.
A hydrogen peroxide aqueous solution was gradually added to initiate polymerization. Thereafter, the reaction was carried out while controlling the addition rate of the hydrogen peroxide aqueous solution and the flow rate of cooling water so as to maintain a constant polymerization rate and polymerization temperature. From the polymerization conversion rate of about 8%, the total amount is 60
The addition of kg vinyl chloride monomer was started at a rate of 15 kg / h. Further, from the time when the polymerization conversion rate reached about 10%, a 7.7% aqueous solution of polyoxyethylene alkyl ether sulfate sodium salt (having 12 carbon atoms in the alkyl group and 2 polyoxyethylene units) (total volume: 6 liters) , 462 g) as a sodium salt of sulfuric acid ester of polyoxyethylene alkyl ether) was continuously added at a rate of 1 liter / h. The pressure inside the tank was 1.0 kg / cm ² (100 k
Pa) When it decreased, the polymerization was stopped and the unreacted monomer was recovered. The reaction temperature was 6 hours, the solid content concentration of the obtained aqueous dispersion was 37%, and the polymer particles in the aqueous dispersion had a solid content concentration of 99.
6% was in the range of 0.08 to 2 μm in particle diameter, the median diameter was 0.86 μm, and the ratio of the peak particle diameter to the median diameter was 1.16. The L% was 79% and the S% was 20.6%. (Fig. 2)

This aqueous dispersion was dried according to (3) above.
It is pulverized to obtain vinyl chloride polymer.
By the method of (5) ~ (7), the plastisol viscosity, viscosity stability,
And the gelation property was evaluated. The results are shown in Tables 1 and 2.

Example 2 At the time of seeded emulsion polymerization in Example 1, as a water-soluble polymerization initiator, a mixed solution of 0.4% hydrogen peroxide aqueous solution and 0.2% potassium persulfate aqueous solution (in all peroxides) Polymerization was performed in the same manner as in Example 1 except that the hydrogen peroxide ratio was 50 mol%. The reaction time was 5.7 hours, and the solid content concentration of the obtained aqueous dispersion was 39%.
99% of the polymer particles in the aqueous dispersion are in the range of 0.08 to 2 μm in particle diameter, the median diameter is 0.74 μm, and the ratio of the peak particle diameter to the median diameter is 1.35. It was L% was 67% and S% was 32%. (FIG. 2) A vinyl chloride polymer was prepared in the same manner as in Example 1, and a plastisol based on this was evaluated. Table 1 shows the results.
And Table-2.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that 0.2% aqueous solution of potassium persulfate was used as the water-soluble polymerization initiator in the seeded emulsion polymerization of Example 1. The reaction time was 6.7 hours, the solid content concentration of the obtained aqueous dispersion was 39%, and 99.2% of the polymer particles in the aqueous dispersion were in the range of particle diameter 0.08 to 2 μm. ,
The median diameter was 0.67 μm, and the ratio of the peak particle diameter to the median diameter was 1.49. Also, L% is 61
% And S% were 38.2%. (FIG. 2) A vinyl chloride polymer was prepared in the same manner as in Example 1, and a plastisol based on this was evaluated. Table 1 shows the results.
And Table-2.

<Comparative Example 2> When the seed polymer of Example 1 was produced, the operating conditions of the emulsifier were set to a primary pressure of 200 kg / cm.
^The polymerization reaction was carried out in the same manner as in Example 1 except that the secondary pressure was changed to ² kg and the secondary pressure was 50 kg / cm ² G. The reaction time was 7.5 hours, the solid content concentration of the obtained aqueous dispersion was about 32%, and the median diameter of the polymer particles in the dispersion was 0.45 μm.
m, the ratio of the peak particle diameter to the median diameter was 0.68. The residual polymerization initiator was decomposed in the same manner as in Example 1 with respect to this polymer, and seeded emulsion polymerization was performed using this as a seed polymer. The reaction time of seed emulsion polymerization was 7 hours, the solid content concentration of the obtained aqueous dispersion was 36%, and 99% of the polymer particles were in the range of particle diameter 0.08 to 2 μm. The median diameter is 0.74 μm, the ratio of the peak particle diameter to the median diameter is 1.04, and L% is 68.
% And S% were 31%. (FIG. 2) A vinyl chloride polymer was prepared in the same manner as in Example 1, and a plastisol based on this was evaluated. Table 1 shows the results.
And Table-2.

<Comparative Example 3> Example 3 was carried out except that the amount of the oil-soluble polymerization initiator lauroyl peroxide was 600 g (1.0% based on the vinyl chloride monomer) at the time of producing the seed polymer of Example 1. A polymerization reaction was carried out in the same manner as in Example 1. The obtained polymer particles contained 0.8% lauroyl peroxide, and had a median diameter of 0.5 μm and a ratio of the peak particle diameter to the median diameter of 1.34.

Polymer particles containing the above oil-soluble polymerization initiator (lauroyl peroxide) are used as they are as a seed polymer without decomposing the residual oil-soluble polymerization initiator, and a new water-soluble polymerization initiator is added. The seed emulsion polymerization was carried out in the same manner as in Example 1 except that it was not carried out. The reaction time was 8.5 hours, and the solid content concentration of the obtained aqueous dispersion was 37%.
However, 97.8% of the polymer particles had a particle size of 0.08.
Was in the range of ˜2 μm. The median diameter of the polymer particles was 0.96 μm, the ratio of the peak particle diameter to the median diameter was 1.04, L% was 88% and S% was 9.8%.
(FIG. 2) A vinyl chloride polymer was prepared in the same manner as in Example 1, and a plastisol based on this was evaluated. Table 1 shows the results.
And Table-2.

Example 3, Comparative Examples 4 and 5 (plastisol and
And production of gloves and evaluation) <Example 3> Vinyl chloride polymer 10 obtained in Example 1
0 parts by weight of diisononyl phthalate 100 parts by weight, epoxidized soybean oil 1 part by weight, calcium stearate 2.5
Blended with 0.5 part by weight of zinc stearate and mixed with a mixer (HOBART MIXER N-50 type, THE
HOBART MFG.CO.) to obtain a plastisol. The evaluation of this plastisol is as follows (8)
Follow the procedure from (10). The results are shown in Table-3. Next, heat the glove mold to 50 ° C and add 1 to the above plastisol at room temperature.
After soaking for 0 seconds, pulling up, and then cutting for 10 minutes,
ROTA MATIC INC's rotational molding machine MODE
Using a L1600L type, the mold is rotated at 15 rpm in an atmosphere of 220 ° C. for 7 minutes, cooled, and demolded at 45 ° C. to obtain a glove. This glove is evaluated by the method (11) below. The results are shown in Table-3.

<Comparative Example 4> A plastisol and gloves were prepared in the same manner as in Example 3 except that the vinyl chloride polymer obtained in Comparative Example 3 was used.
Follow the steps (8) to (11). The results are shown in Table-3.

Comparative Example 5 A plastisol and gloves were prepared in the same manner as in Example 3 except that a commercially available vinyl chloride polymer (Z121 manufactured by Nippon Zeon Co., Ltd.) was used. Evaluation is performed by the following methods (8) to (11). The results are shown in Table-3.

(Evaluation of Plastisol) (8) Viscosity: Plastisol was left in a 45 ° C. water bath for 2 hours, and then B8H type viscometer (using # 3 rotor) manufactured by Tokimec Co., Ltd.
Rotation speed of ₅ rpm (referred to as “B ₅ ”) and 10 r
It is measured by pm (described as "B ₁₀ ").

(9) Yield value (Y): Yield value (Y) according to the following equation
Is calculated and used as an index of sagging property. The larger Y is, the more uniform the glove can be obtained. Y = 12 (B ₅ (cps) -B ₁₀ (cps) ) / 100 (10) Sedimentation: Plastisol is put in a 500 ml mayonnaise bottle and left in a thermostatic chamber at 45 ° C. for 7 days, and the presence or absence of sedimentation of the vinyl chloride polymer is examined.

(Evaluation of gloves) (11) Pinholes: 10 pairs of gloves each (total 30)
For feet, inject water into the gloves and suspend them, and inspect for water leakage. Table 3 shows the number of gloves that leaked.

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[Table 1] Polymerization initiator: H ₂ O ₂ = hydrogen peroxide, KPS = potassium persulfate The particle size unit is μm, and the gelling time unit is minutes.

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[Table 2]

[0069]

[Table 3]

[0070]

The vinyl chloride-based polymer aqueous dispersion of the present invention is dried to obtain a vinyl chloride-based polymer, and when the vinyl chloride-based polymer is mixed with a plasticizer to form a plastisol, the viscosity is It has a low viscosity and a small increase in viscosity during storage, which is advantageous when manufacturing, storing, or transferring plastisol. Further, since this plastisol is rapidly gelled by heating, the processing speed can be increased and the productivity during processing can be increased.

[Brief description of drawings]

FIG. 1 Example of particle size distribution of vinyl chloride polymer aqueous dispersion (seed polymer and seed emulsion polymer (single peak distribution))

FIG. 2 Particle size distribution of vinyl chloride polymer aqueous dispersions obtained in Examples and Comparative Examples

FIG. 3 Particle size distribution of plastisol of vinyl chloride polymers obtained in Examples and Comparative Examples

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[Explanation of symbols]

Dp: peak particle size of polymer particles in aqueous dispersion Dp ': peak particle size of polymer particles in plastisol Dm: median diameter of polymer particles in aqueous dispersion Dm': of polymer particles in plastisol Median diameter L%: Proportion of polymer particles having a particle diameter of 0.5-2 μm within the range of particle diameter of 0.08-2 μm relative to the total amount of polymer particles in an aqueous dispersion L ′%: particle diameter 0.08-2 μm Ratio of polymer particles having a particle diameter of 0.5 to 2 μm to the total amount of polymer particles in the plastisol S%: particle diameter within the above range 0.08 to 0.5 μ
Ratio of polymer particles of m to the total amount of polymer particles in the aqueous dispersion S '%: Particle diameter within the above range 0.08 to 0.5 μ
Ratio of polymer particles of m to the total amount of polymer particles in plastisol

Claims (8)

[Claims] 1. Seeding emulsion polymerization of vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable therewith (hereinafter collectively referred to as "vinyl chloride-based monomer") in the presence of a seed polymer. Or particles of a vinyl chloride polymer aqueous dispersion obtained by seeding fine suspension polymerization, which represents the relationship between the particle size and the weight ratio (%) of the polymer particles of that particle size to all particles A vinyl chloride polymer aqueous dispersion having a size distribution (hereinafter abbreviated as "particle size distribution") having the following characteristics (a) to (e). (A) The graph of particle size distribution is a distribution (single peak distribution) having only one maximum value in the range of 0.08 to 2 μm. (B) The particle size that gives the maximum value in (a) (hereinafter,
It is described as "peak particle size" and represented by "Dp") is 0.8 to
Within the range of 1.8 μm. (C) 98% by weight or more of the polymer particles in the aqueous dispersion are in the range of 0.08 to 2 μm in particle size. (D) 65 to 87% by weight of the polymer particles in the aqueous dispersion is in the range of 0.5 to 2 μm in particle size. (E) 11 to 33% by weight of the polymer particles in the aqueous dispersion is in the range of particle diameter 0.08 to 0.5 μm. 2. A peak particle diameter with respect to a particle diameter (hereinafter referred to as "median diameter", represented by "Dm") at which the integrated value of the weight ratio of the polymer particles in the aqueous dispersion reaches 50% by weight in the particle size distribution. The aqueous dispersion according to claim 1, wherein the ratio (Dp / Dm) is 1.05 to 1.4. 3. A vinyl chloride system having a median diameter of 0.4 to 0.9 μm and a Dp / Dm of 0.7 to 1.8 produced by fine suspension polymerization as a seed polymer. The method for producing an aqueous dispersion of a vinyl chloride polymer according to claim 1 or 2, wherein the polymer is used and seeded emulsion polymerization is carried out using hydrogen peroxide as a water-soluble polymerization initiator. 4. The method for producing an aqueous dispersion according to claim 3, wherein a vinyl chloride polymer having an oil-soluble polymerization initiator content of 0.1% by weight or less based on the seed polymer is used as the seed polymer. . 5. The method for producing an aqueous dispersion according to claim 3, wherein a sulfuric acid ester salt of polyoxyethylene alkyl ether is used as an emulsifier in the seed emulsion polymerization. 6. A vinyl chloride polymer obtained by seeding emulsion polymerization or seeding fine suspension polymerization of a vinyl chloride monomer in the presence of a seed polymer, the vinyl chloride polymer comprising: Particle size of polymer particles in plastisol prepared using and weight ratio (%) of polymer particles of that particle size to all particles
A vinyl chloride polymer having the following characteristics (f) to (j) in which the particle size distribution representing the relationship with (F) The graph of particle size distribution is a distribution (single peak distribution) having only one maximum value in the range of 0.08 to 2 μm. (G) The particle diameter that gives the maximum value in (f) (hereinafter,
"Peak particle size", expressed as "Dp '") is 0.8 to
Within the range of 1.8 μm. (H) 98% by weight or more of the polymer particles in the plastisol are in the range of particle diameter 0.08 to 2 μm. (I) 65-87% by weight of polymer particles in plastisol
Is in the range of 0.5 to 2 μm. (J) 11-33% by weight of polymer particles in plastisol
Is in the range of 0.08 to 0.5 μm. 7. The peak particle size relative to the particle size (hereinafter referred to as "median size", represented by "Dm '") when the cumulative value of the weight ratio of the polymer particles in the plastisol reaches 50% by weight in the particle size distribution. The ratio (Dp ′ / Dm ′) is 1.05 to 1.
The vinyl chloride polymer according to claim 6, which is 4. 8. A glove manufactured using the vinyl chloride polymer according to claim 6.