KR101768284B1 - Paste vinyl chloride resin and preparing method thereof - Google Patents

Abstract

The present invention relates to a paste vinyl chloride resin containing a potassium phosphate coating layer on a surface having improved initial physical properties and low viscosity over time, and a method for producing the same. As a result, the viscosity of the paste vinyl chloride resin can be restrained from increasing with time due to penetration of the plasticizer, so that the viscosity stability is excellent, the decomposition of the foaming agent can be activated, and the foaming property can be excellent. Accordingly, the paste vinyl chloride resin according to the present invention and the method for producing the same can be easily applied to an industry that needs it, particularly to the wallpaper industry.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride resin,

The present invention relates to a paste vinyl chloride resin containing a potassium phosphate coating layer on a surface having improved initial physical properties and low viscosity over time, and a method for producing the same.

BACKGROUND ART Vinyl chloride resins are widely used as general industrial resins for living and industrial use. Straight vinyl chloride resins are generally prepared by suspension polymerization using powder particles having a size of about 100 to 200 mu m, The vinyl resin is a powder particle having a size of about 0.1 to 2 μm and is produced by an emulsion polymerization method.

In general, a paste vinyl chloride resin is prepared by spray drying a latex obtained by emulsion polymerization to form final resin particles, and the particles are dispersed in a solvent or a plasticizer to perform reverse roll-coating, knife coating, screen coating, wallpaper, tarpaulins, gloves, gloves, automotive underbody, etc., through processes such as spray coating, gravure and csreen printing, ratocity casting, shell casting and dipping. Coating, and carpet tiles.

Such a paste vinyl chloride resin alone is difficult to apply because of low workability and is usually processed into a plastisol form which is composed of various additives such as a heat stabilizer together with a plasticizer. In order to improve workability, It is important to lower the viscosity of the sol to maintain good flowability.

In order to achieve the above object, conventionally, a suspension polymerized vinyl chloride resin having a size of 30 to 40 탆 is mixed with a paste vinyl chloride resin plastisol at 10 to 20% by weight to lower the viscosity of the plastisol, Has been used to improve the workability. This reduces the viscosity of the plastisol during processing by reducing the pore size and reducing the plasticizer absorption area by mixing and filling of vinyl chloride resins having different sizes of particles. However, such plasticizer absorbability is deeply related to the size and spherical shape of the mixed vinyl chloride resin particles, so that the spherical shape of the final particles and the control of particle size are required, and there is a problem in that it is troublesome to mix polymerized vinyl chloride resins differently .

On the other hand, the paste-vinyl chloride resin plastisol blended has a portion where the viscosity increases with the lapse of time, and when applied to wallpaper processing, the viscosity of the plastisol blended in a large amount varies with time Which is a problem of increasing the thickness of the film.

In addition, in general, the wallpaper vinyl chloride type resin plastisol for wallpaper is required to have not only the above-described viscosity characteristics, but also excellent properties in foam properties (e.g., expansion ratio and whitening whiteness). Such foam properties can be improved by raising the drying temperature at the time of producing the paste vinyl chloride resin, but the viscosity is also increased, resulting in a problem that the workability is lowered.

Therefore, in order to easily apply the paste-type vinyl chloride resin to various fields, particularly the wallpaper industry, there is a need for a technique for improving foam properties with excellent viscosity characteristics.

KR 10-1102278 B1

SUMMARY OF THE INVENTION The present invention has been conceived to solve the above-mentioned problems, and it is an object of the present invention to provide a paste vinyl chloride resin containing a potassium phosphate coating layer on a surface having excellent initial viscosity and aged viscosity and improved foam properties.

Another object of the present invention is to provide a method for producing the above-mentioned paste vinyl chloride resin through seed emulsion polymerization, wherein sodium hydroxide and potassium phosphate are introduced at a polymerization conversion rate of 85% or more.

In order to solve the above problems, the present invention provides a paste vinyl chloride resin including a potassium phosphate coating layer on its surface.

The present invention also relates to a process for preparing a seed latex mixture by mixing a first seed latex and a second seed latex (Step 2); And a step (2) of charging the seed latex mixture with a vinyl chloride monomer and emulsion polymerization (step 2), wherein the emulsion polymerization is carried out in the presence of sodium hydroxide and potassium phosphate, and the sodium hydroxide and potassium phosphate have a polymerization conversion of 85% By weight based on the total weight of the resin composition.

Since the paste vinyl chloride resin according to the present invention contains a potassium phosphate coating layer on its surface, the viscosity increase due to penetration of the plasticizer can be suppressed, the viscosity stability is excellent, the sodium hydroxide is contained, and the decomposition of the foaming agent can be activated The foamed material properties can be excellent.

In the method for producing a paste vinyl chloride resin according to the present invention, a potassium phosphate coating layer may be formed on the surface of the paste vinyl chloride resin by adding sodium hydroxide and potassium phosphate to the late phase of polymerization in appropriate proportions, Can remain in the paste-based vinyl chloride resin. Accordingly, the viscosity characteristics and foam properties of the paste-type vinyl chloride resin can be improved.

Accordingly, the paste vinyl chloride resin according to the present invention and the method for producing the same can be easily applied to an industry that needs it, particularly to the wallpaper industry.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

The terms and words used in the present specification and claims should not be construed in an ordinary or dictionary sense and the inventor can properly define the concept of the term to describe its invention in the best possible way It should be construed as meaning and concept consistent with the technical idea of the present invention.

The present invention provides a paste vinyl chloride resin having low initial viscosity, low viscosity over time, excellent viscosity stability, and excellent foam properties.

The paste vinyl chloride resin according to an embodiment of the present invention is characterized by including a potassium phosphate coating layer on its surface.

The potassium phosphate coating layer may be a water-absorbing layer, and may be formed by putting potassium phosphate into a polymerization vessel or a vinyl chloride resin particle as described in the production method described later. At this time, the coating layer may be formed on at least a part of the surface of the paste vinyl chloride resin, specifically, it may be formed so as to surround the entire surface of the paste vinyl chloride resin.

The paste vinyl chloride resin according to the present invention has a potassium phosphate coating layer, that is, a moisture adsorption layer formed on its surface, and the plasticizer to be mixed together in the production of the paste vinyl chloride resin plastisol containing the paste is a paste vinyl chloride resin It is possible to inhibit penetration of the resin into the mold and prevent the viscosity from increasing.

Specifically, since the paste vinyl chloride resin has a coating layer (moisture adsorption layer) having hydrophilic properties formed on its surface, the plasticizer having lipophilic properties can not penetrate easily, and an increase in viscosity with time due to the plasticizer can be suppressed have.

In addition, the paste vinyl chloride resin may contain 10 ppm to 1000 ppm of sodium hydroxide. Specifically, the paste vinyl chloride resin may contain 50 ppm to 300 ppm of sodium hydroxide.

The paste vinyl chloride resin according to the present invention may contain a certain concentration of sodium hydroxide in the paste vinyl chloride resin finally prepared by introducing sodium hydroxide into the late stage of polymerization as described in the production method described later. Accordingly, decomposition of the foaming agent to be mixed together during the production of the paste vinyl chloride resin plastisol containing the same can be promoted to improve the foaming property.

On the other hand, the paste-type vinyl chloride resin may have an initial viscosity of 2000 cP to 8000 cP as measured by a BF viscometer, and a viscosity of 1 day as measured by a BF viscometer may be 2000 cP to 28000 cP. The viscosity of the paste-type vinyl chloride resin may be 1 to 3.5 or less, and the whitening whiteness (WI) may be 30 or more. Specifically, the whitening whiteness (WI) may be 30 to 55.

Here, the initial viscosity and the viscosity with time were determined by preparing a paste vinyl chloride resin plastisol containing the paste vinyl chloride resin, and using a Brookfield viscometer (LV type) using a three-speed spindle stirring speed of 6 rpm . ≪ / RTI > The initial viscosity means that the viscosity of the plastisol is measured after 1 hour from the production of the plastisol. The viscosity of the plastisol per day means that the viscosity of the plastisol is measured after one day, The overdue ratio may be a value calculated by the following equation (1). The whitening whiteness may be a value measured by the same method as described in Experimental Examples described later.

The paste vinyl chloride resin plastisol may be prepared by mixing and adding additives such as a plasticizer, a stabilizer and a foaming agent to the paste vinyl chloride resin. The additives such as the plasticizer, the stabilizer and the foaming agent are not particularly limited, Can be used. On the other hand, the vinyl chloride resin plastisol for the measurement of the initial viscosity and the viscosity with the elapse of time may be prepared by the method described in Experimental Examples described later.

Specifically, the plasticizer may be dioctyl phthalate (DOP), the stabilizer may be a Ba-Zn-based stearate, and the blowing agent may be azodicarbonamide (ADCA).

Further, the present invention provides a method for producing the above-mentioned paste vinyl chloride resin having low initial viscosity, low viscosity over time, excellent viscosity stability, and improved foam properties.

The method for producing a paste vinyl chloride resin according to an embodiment of the present invention includes preparing a seed latex mixture by mixing a first seed latex and a second seed latex (Step 1); And a step (2) of charging the seed latex mixture with a vinyl chloride monomer and emulsion polymerization (step 2), wherein the emulsion polymerization is carried out in the presence of sodium hydroxide and potassium phosphate, and the sodium hydroxide and potassium phosphate have a polymerization conversion of 85% Or more at a time point when the temperature is below a predetermined temperature.

In the step 1, the first seed latex and the second seed latex having different average particle diameters are mixed to increase the binding force of the vinyl chloride-based monomer and to give a bimodal effect to the vinyl chloride polymer finally produced To prepare a seed latex mixture. The seed latex mixture is not particularly limited and may be a mixture of the first seed latex and the second seed latex at an appropriate weight ratio as desired. Specifically, the seed latex mixture may be a mixture of the first seed latex and the second seed latex May be mixed in a weight ratio of 5: 1 to 5: 5.

The first seed latex may have an average particle diameter of 0.5 탆 to 1.0 탆, and the second seed latex may have an average particle diameter of 0.1 탆 to 0.5 탆.

Hereinafter, the first seed latex will be specifically described.

The first seed latex may be prepared by adding a vinyl chloride monomer and an emulsifier to a reactor filled with a polymerization initiator, homogenizing the emulsion, and then emulsifying the emulsion at a temperature of 30 ° C to 70 ° C.

The reactor filled with the polymerization initiator may be a reactor containing a mixed solution containing a polymerization initiator. In addition to the polymerization initiator, the mixed solution may further contain polymerized water, a separate emulsifier, a reaction inhibitor, a dispersant, and the like , But is not limited thereto.

The vinyl chloride monomer may be a pure vinyl chloride monomer as well as a mixture of a vinyl chloride monomer and a vinyl monomer copolymerizable with the vinyl chloride monomer. At this time, when the vinyl chloride monomer is a mixture of vinyl chloride monomers and vinyl monomers, it may be preferable that the vinyl chloride monomers include 50 wt% or more of the vinyl chloride monomer.

Examples of the vinyl monomer copolymerizable with the vinyl chloride monomer include, but are not limited to, olefin compounds such as ethylene, propylene and butene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl stearate, Unsaturated nitriles such as acrylonitrile and the like, vinyl alkyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl octyl ether and vinyl launy ether, vinylidene halides such as vinylidene chloride, acrylic acid, methacrylic Unsaturated fatty acid esters such as maleic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride and itaconic anhydride and anhydrides of these fatty acids, unsaturated fatty acid esters such as methyl acrylate, ethyl acrylate, monomethyl maleate, dimethyl maleate, butyl benzyl maleate, And diallyl phthalate, and the like, and the vinyl-based monomer It may be mixed alone or in combination of two or more.

The polymerization initiator may be used in an amount of 0.01 part by weight to 2 parts by weight based on 100 parts by weight of the vinyl chloride monomer. The average particle diameter of the first seed latex may be adjusted depending on the amount of the polymerization initiator used have. For example, as the amount of the polymerization initiator used increases, the average particle diameter of the first seed produced may decrease.

The polymerization initiator is not particularly limited but may be an oil-soluble polymerization initiator, and may be one or more selected from the group consisting of peroxycarbonates, peroxyesters and azo compounds. Specifically, the polymerization initiator may be selected from the group consisting of diisopropyl peroxy dicarbonate, t-butyl peroxy pivalate, t-butyl peroxyneodecanoate, 2,2-azobisisobutyronitrile, Two or more species may be used in combination. Preferably, the polymerization initiator may be lauryl peroxide (LPO), di-2-ethylhexyl peroxycarbonate (OPP), or a mixture thereof.

The emulsifying agent may be used in an amount of 0.1 part by weight to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer. The emulsifying agent is not particularly limited and conventional materials known in the art can be used. Examples thereof include sodium lauryl sulfate, It may be at least one member selected from the group consisting of benzenesulfonic acid, alpha-olefin sulfonate, sodium lauryl ethoxylate sulfate, sodium octadecyl sulfate, sodium lauryl ether sulfate, and straight chain alkyl benzene sulfonate.

The reaction inhibitor may be paraquinone or the like. The dispersing agent is not particularly limited, and for example, higher alcohols such as lauryl alcohol, myristic alcohol and stearyl alcohol, or higher fatty acids such as lauryl acid, myristic acid, palmitic acid and stearic acid can be used .

The homogenization may be performed by homogenizing for 1 hour to 3 hours using a homogenizer at a temperature of 20 DEG C or less, preferably 5 DEG C to 15 DEG C, though not particularly limited. At this time, the homogenizer is not particularly limited and conventional ones known in the art can be used. For example, a rotor-stator type homogenizer can be used.

The polymerization may be carried out at a temperature of 30 ° C to 70 ° C as described above. More specifically, the emulsion polymerization is started by raising the temperature at 40 ° C to 50 ° C at the homogenization performance temperature, and polymerization is carried out for 5 hours to 15 hours And may be performed in advance.

Hereinafter, the second seed latex will be specifically described.

The second seed may be produced by the following method:

a) introducing 100 parts by weight of a vinyl chloride monomer into a reactor packed with the first emulsifier and initiating polymerization at a temperature of 30 ° C to 70 ° C; And

b) continuously injecting the second emulsifier during the polymerization and performing emulsion polymerization for 4 to 10 hours.

The reactor packed with the first emulsifier of step a) represents a reactor containing an emulsion containing the first emulsifier, and the emulsion may include polymerization water, a polymerization initiator, etc. in addition to the first emulsifier.

The first emulsifier may be used in an amount of 0.01 part by weight to 1 part by weight based on 100 parts by weight of the vinyl chloride monomer. The average particle diameter of the second seed latex may be adjusted depending on the amount of the first emulsifier. For example, as the amount of the first emulsifier used increases, the average particle diameter of the second seed latex may be increased.

At this time, the vinyl chloride monomer may be as described above.

The polymerization initiator may be preferably a water-soluble initiator, and specifically may be one or more selected from the group consisting of potassium persulfate, ammonium persulfate, and hydrogen peroxide.

The second emulsifier in step b) is continuously introduced into the reactor during the emulsion polymerization and may be used in an amount of 0.01 to 6 parts by weight based on 100 parts by weight of the vinyl chloride monomer.

The first emulsifier and the second emulsifier may be the same as or included in the emulsifier used in the first seed latex production described above.

Step 2 is a step of introducing a vinyl chloride monomer into the seed latex mixture to obtain a paste vinyl chloride resin, followed by emulsion polymerization. In this case, the emulsion polymerization may be carried out in the presence of sodium hydroxide and potassium phosphate as described above.

The emulsion polymerization may be initiated by introducing a vinyl chloride monomer and an emulsifier into a reactor in which the seed latex mixture and the polymerization water are mixed, and during the polymerization reaction, sodium hydroxide and potassium phosphate may be added to proceed the polymerization. At this time, sodium hydroxide and potassium phosphate may be added at a polymerization conversion rate of 85% or more, specifically, at a polymerization conversion rate of 85% to 90%.

On the other hand, the emulsifier may be continuously added during the emulsion polymerization, and the emulsion polymerization may be carried out by further adding additives such as a polymerization initiator, a molecular weight adjuster, and an electrolyte, if necessary.

Specifically, in the emulsion polymerization, 100 parts by weight of a vinyl chloride monomer and 0.2 parts by weight of an emulsifier 0.2 were added to a reactor containing 70 parts by weight to 120 parts by weight of polymerization water and 1 part by weight to 20 parts by weight of a seed latex mixture per 100 parts by weight of the vinyl chloride monomer. To 2.5 parts by weight, and initiating polymerization at a temperature range of 30 to 70 ° C, and adding sodium hydroxide and potassium phosphate at a time when the polymerization conversion ratio is 85% or more. At this time, sodium hydroxide and potassium phosphate may be added at a weight ratio of 0.5: 1 to 2: 1. Specifically, sodium hydroxide and potassium phosphate can be added at a weight ratio of 1: 1. On the other hand, the potassium phosphate may be added in an amount of 0.1 pphm (parts per hundred monomer) or less based on the vinyl chloride monomer.

If necessary, additives such as 0.1 part by weight to 1.5 parts by weight of a polymerization initiator, 0.5 parts by weight to 2 parts by weight of an electrolyte and 0.1 parts by weight to 1 part by weight of a molecular weight adjusting agent are added to 100 parts by weight of the vinyl chloride monomer The reaction can proceed.

The vinyl chloride monomer may be as described above.

The polymerization initiator may be one or more of the above-described oil-soluble polymerization initiator and water-soluble polymerization initiator, and the above-mentioned emulsifier may be as described above.

The molecular weight regulator is not particularly limited, but may be, for example, n-butyl mercaptan, n-octylmercaptan, n-dodecylmercaptan, t-dodecylmercaptan and the like.

Examples of the electrolyte include, but are not limited to, potassium chloride, sodium chloride, potassium bicarbonate, potassium carbonate, potassium hydrogen sulfite, sodium hydrogen sulfite, sodium pyrophosphate, sodium pyrophosphate, tripotassium phosphate, trisodium phosphate, Potassium, and disodium hydrogenphosphate.

In addition, the method according to the present invention may further include a step of adding a buffer before the initiation of polymerization, and the buffer may be added in an amount of 0.02 parts by weight to 0.2 parts by weight based on 100 parts by weight of the vinyl chloride monomer.

The buffer may be at least one selected from the group consisting of sodium hydroxide, potassium phosphate, potassium bicarbonate, sodium bicarbonate, and ammonium sulfate, but is not limited thereto.

The method for producing the paste vinyl chloride resin by emulsion polymerization according to the present invention is characterized in that sodium hydroxide and potassium phosphate are added at a later stage of polymerization, specifically at a point of time when the conversion rate is 85% or more, A potassium phosphate coating layer may be formed on the surface of the vinyl chloride resin, and a proper amount of sodium hydroxide may remain. Thus, a paste vinyl chloride resin having a low initial viscosity and a low viscosity over time and excellent foam properties can be produced.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. However, the following examples and experimental examples are provided for illustrating the present invention, and the scope of the present invention is not limited thereto.

Example  One

A second high-pressure reactor was charged with 66 parts by weight of deionized water, 0.027 part by weight of potassium phosphate (KH ₂ PO ₄ ), 0.009 part by weight of sodium hydroxide, 7.5 parts by weight of a first seed latex (0.2 μm, solid content 40% (0.6 mu m, solid content 40%) were put into a reactor, and then vacuum was applied to the reactor at -1 kg / cm < ² >. 100 parts by weight of vinyl chloride monomer, 1 part by weight of sodium lauryl sulfate and 0.002 parts by weight of ferrous sulfate were charged into a reactor in a vacuum state, and the temperature of the reactor was raised to 61 캜 to initiate polymerization. When the polymerization reaction is started, 0.01 part by weight of ascorbic acid is continuously added to 0.002 part by weight per hour for 5 hours. When the reactor pressure reached 4 kg / cm ² , the reaction was terminated and unreacted vinyl chloride monomer was recovered and removed. 0.02 part by weight of sodium hydroxide and 0.02 part by weight of potassium phosphate were added at the polymerization conversion rate of 85% (at the time when the pressure completely disappeared), stirred for 10 minutes, and spray-dried to prepare powder phase vinyl chloride resin.

Example  2

A powdery phase paste of vinyl chloride resin was prepared in the same manner as in Example 1, except that potassium phosphate was added in an amount of 0.01 part by weight instead of 0.02 part by weight at a polymerization conversion of 85%.

Example  3

A powdery phase paste vinyl chloride resin was prepared in the same manner as in Example 1, except that 0.01 part by weight of sodium hydroxide was added at a polymerization conversion of 85% instead of 0.02 part by weight.

Example  4

A powdery phase paste of vinyl chloride resin was prepared in the same manner as in Example 1, except that sodium hydroxide and potassium phosphate were added in amounts of 0.01 part by weight instead of 0.02 part by weight, respectively, at a polymerization conversion of 85%.

Comparative Example  One

Powder phase paste vinyl chloride resin was prepared in the same manner as in Example 1, except that sodium hydroxide and potassium phosphate were not added at a polymerization conversion of 85%.

Comparative Example  2

Powder phase paste vinyl chloride resin was prepared in the same manner as in Example 1, except that potassium phosphate was not added at a polymerization conversion rate of 85%.

Comparative Example  3

A powdery phase paste vinyl chloride resin was prepared in the same manner as in Example 1 except that sodium hydroxide which was added at a polymerization conversion rate of 85% was added in an amount of 0.01 part by weight instead of 0.02 part by weight and potassium phosphate was not added .

Comparative Example  4

A powdery phase paste vinyl chloride resin was prepared in the same manner as in Example 1 except that sodium hydroxide was not added at a polymerization conversion rate of 85%.

Comparative Example  5

A powdery phase paste of vinyl chloride resin was prepared in the same manner as in Example 1, except that 0.01 weight part of potassium phosphate added at a polymerization conversion rate of 85% was used instead of 0.02 weight part, and sodium hydroxide was not added.

Experimental Example

In order to comparatively analyze the viscosity and foaming properties of the respective paste vinyl chloride resins prepared in Examples 1 to 4 and Comparative Examples 1 to 5, initial viscosity, viscosities over 1 day, expansion ratio and whitening whiteness were measured. The results are shown in Table 1 below.

1) Initial viscosity, 1-day aged viscosity and viscosity aging rate

60 g of dioctyl phthalate (DOP) was added to 100 g of each of the paste vinyl chloride resins prepared in Examples 1 to 4 and Comparative Examples 1 to 5 using a stirrer (Eurostar IKA) at 800 rpm for 10 minutes, And the mixture was degassed for 10 minutes to prepare each plastisol.

The initial viscosity was measured with a 3-spindle at 6 rpm using a BF viscometer after placing each of the prepared plistysol in a constant temperature and humidity (25 ° C., 50% humidity) for 1 hour, The sol was placed in a constant temperature and humidity chamber (25 ° C, 50% humidity) for 24 hours and then measured at 6 rpm with a 3-spindle using a BF viscometer. Also, the viscous overage ratio was calculated by the following equation (1).

[Equation 1]

2) Foaming magnification and foam whiteness (W.I)

60 g of dioctyl phthalate (DOP), 2 g of a Ba-Zn type stabilizer and 2 g of an ADCA (azodicarbonamide) blowing agent were added to 100 g of each of the paste vinyl chloride resins prepared in Examples 1 to 4 and Comparative Examples 1 to 5, (Eurostar IKA) at 800 rpm for 10 minutes, and defoamed for 10 minutes using a vacuum machine to prepare each foamed plastisol.

Each foamed plastisol prepared above was uniformly coated on a white paper at a thickness of 0.5 mm, and each sheet pre-gelled at 150 ° C for 45 seconds was prepared. Each of the pre-gelled sheets was subjected to heat of 205 DEG C for 90 seconds to prepare each foamed sheet. The expansion ratio was calculated by the following equation (2).

division Viscosity characteristic Presentation properties Initial viscosity (cP) Aging viscosity (cP) Viscosity over time ratio Presentation magnification Foaming whiteness (W.I) Example 1 4000 6000 1.5 3.60 41 Example 2 7000 22000 3.14 3.55 46 Example 3 3500 5000 1.43 3.56 31 Example 4 3900 6300 1.61 3.58 33 Comparative Example 1 5000 10000 2.0 3.53 25 Comparative Example 2 19000 80000 4.21 3.58 50 Comparative Example 3 11000 42900 3.90 3.59 35 Comparative Example 4 3000 4000 1.33 3.45 18 Comparative Example 5 4000 6200 1.55 3.44 22

As shown in Table 1, the paste vinyl chloride resins of Examples 1 to 4 according to the present invention exhibited excellent viscosity characteristics and foam properties as compared with the paste vinyl chloride resins of Comparative Examples 1 to 5.

Concretely, in the case of the paste vinyl chloride resin of Comparative Example 1 in which sodium hydroxide and potassium phosphate were not added to the late stage of polymerization, the initial viscosity was higher and the viscous aged ratio was remarkably higher than that of the paste vinyl chloride resin of Examples 1 to 4 And the whitening whiteness was remarkably lowered. This is because the paste vinyl chloride resin of Examples 1 to 4 prepared by the production method according to the present invention is prepared by putting sodium hydroxide and potassium phosphate into the latter stage of polymerization so that the potassium phosphate is coated on the surface of the paste vinyl chloride resin as a coating layer , Which means that the penetration of the plasticizer is suppressed and as a result, the viscosity increase over time is suppressed. In addition, this means that the sodium hydroxide remains in the paste vinyl chloride resin at a certain concentration, thereby activating decomposition of the foaming agent and improving foaming properties.

In addition, in the case of the paste vinyl chloride resin of Comparative Examples 2 to 5 prepared by adding sodium hydroxide or potassium phosphate to the late stage of polymerization, the viscosity of the paste vinyl chloride resin of Comparative Examples 2 to 5 was comparable to that of the paste vinyl chloride resins of Examples 1 to 4 Or foam properties. That is, the viscosity of the paste vinyl chloride resin of Comparative Examples 2 and 3 prepared by adding only sodium hydroxide to the late stage of polymerization was significantly lower than that of the paste vinyl chloride resins of Examples 1 to 4, but the foam properties were similar, In contrast, the paste vinyl chloride resins of Comparative Examples 4 and 5 prepared by adding only potassium phosphate to the late phase of polymerization showed significantly lower foam properties than the paste vinyl chloride resins of Examples 1 to 4, but showed similar viscosity characteristics. It is important to mix sodium hydroxide and potassium phosphate in combination with the manufacturing method according to the present invention in order to exhibit excellent viscosity characteristics and foam physical properties. In order to obtain the desired viscosity and foaming properties, sodium hydroxide and sodium hydroxide It is important to mix potassium phosphate in an appropriate ratio.

As shown in the above results, the paste vinyl chloride resin prepared through the manufacturing method including the step of injecting sodium hydroxide and potassium phosphate into the polymerization late stage according to the present invention can include a potassium phosphate coating layer on the surface, At the same time, sodium hydroxide can be contained at a certain concentration, thereby exhibiting low initial viscosity, excellent viscosity stability, low viscosity over time, and excellent foaming properties.

Claims (20)

The surface of which includes a potassium phosphate coating layer,
10 ppm to 1000 ppm of sodium hydroxide,
Wherein the initial viscosity measured by a BF viscometer is 2000 cP to 8000 cP, the viscosity overage ratio is 1 to 3.5, and the whitening whiteness (WI) is 30 or more.
The method according to claim 1,
Wherein the coating layer is a water-absorbing layer.
delete delete delete delete Mixing the first seed latex and the second seed latex to prepare a seed latex mixture; And
Adding a vinyl chloride monomer to the seed latex mixture and emulsion-polymerizing the seed latex mixture,
The emulsion polymerization is carried out in the presence of sodium hydroxide and potassium phosphate,
Wherein the sodium hydroxide and potassium phosphate are added at a weight ratio of 0.5: 1 to 2: 1 at a polymerization conversion of 85% or more.
delete The method of claim 7,
Wherein the sodium hydroxide and potassium phosphate are charged at a polymerization conversion of 85% to 90%.
The method of claim 7,
Wherein the first seed latex is prepared by adding a vinyl chloride monomer and an emulsifier to a reactor filled with a polymerization initiator and homogenizing the emulsion followed by emulsion polymerization at a temperature of 30 ° C to 70 ° C. ≪ / RTI >
The method of claim 10,
The polymerization initiator is an oil-soluble polymerization initiator,
Wherein the oil-soluble polymerization initiator is used in an amount of 0.01 to 2 parts by weight based on 100 parts by weight of the vinyl chloride monomer.
The method of claim 10,
Wherein the emulsifier is used in an amount of 0.1 part by weight to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer.
The method of claim 10,
Wherein the homogenization is carried out at a temperature of 20 DEG C or lower for 1 hour to 3 hours using a homogenizer.
The method of claim 7,
Wherein the first seed latex has an average particle diameter of 0.5 占 퐉 to 1 占 퐉.
The method of claim 7,
The second seed latex
a) introducing a vinyl chloride monomer into a reactor packed with the first emulsifier and initiating emulsion polymerization at a temperature of 30 캜 to 70 캜; And
and b) continuously introducing the second emulsifier during the emulsion polymerization and conducting emulsion polymerization for 4 hours to 10 hours.
16. The method of claim 15,
The first emulsifier is used in an amount of 0.01 part by weight to 1 part by weight based on 100 parts by weight of the vinyl chloride monomer,
Wherein the second emulsifier is used in an amount of 0.01 part by weight to 6 parts by weight based on 100 parts by weight of the vinyl chloride monomer.
The method of claim 7,
Wherein the second seed latex has an average particle diameter of 0.1 to 0.5 占 퐉.
The method of claim 7,
Wherein the seed latex mixture comprises a first seed latex and a second seed latex at a weight ratio of 5: 1 to 5: 5.
The method of claim 7,
The method may further comprise the step of adding a buffer before initiating polymerization,
Wherein the buffer is added in an amount of 0.02 part by weight to 0.2 part by weight based on 100 parts by weight of the vinyl chloride monomer.
The method of claim 19,
Wherein the buffer is at least one selected from the group consisting of sodium hydroxide, potassium phosphate, potassium bicarbonate, sodium bicarbonate, and ammonium sulfate.