JP2019094372A - Vinyl chloride resin for paste - Google Patents

Abstract

To provide a vinyl chloride for paste excellent in thermal stability and transparency when being formed into a floor material, wall paper, a foam sheet and other vinyl chloride molding, specifically, to prevent thermal degradation of the vinyl chloride for paste in spray-drying, in a production step of the vinyl chloride for paste, to improve thermal stability of the vinyl chloride molding, and to improve transparency of the vinyl chloride molding compared to the conventional case using hydrotalcite.SOLUTION: A vinyl chloride for paste having high thermal stability and transparency after molding can be produced by synthesizing hydrotalcite having a smaller primary particle size and good dispersibility, and adding the hydrotalcite in a form of a suspension in polymerization of a vinyl chloride resin. By adding the hydrotalcite before spray-drying, thermal stability is enhanced compared to the case in which the hydrotalcite is added after spray-drying.SELECTED DRAWING: Figure 1

Description

  The present invention is a vinyl chloride-based paste for pastes which is excellent in thermal stability and transparency when it is used as a floor material, wallpaper, foam sheet, or other vinyl chloride-based resin molded article (hereinafter referred to as "PVC molded article"). The present invention relates to a resin composition (hereinafter referred to as "paste polyvinyl chloride").

  Paste PVC is generally processed as a vinyl chloride-based plastisol (hereinafter referred to as "vinyl chloride plastisol") by kneading with a compounding agent such as a plasticizer, a stabilizer, a foaming agent, etc., and is varied according to various processing methods. Good PVC molding is obtained. Among them, building materials such as wallpaper, flooring and foam sheets are one of the main uses of paste PVC.

  As a general production method of paste polyvinyl chloride, first, vinyl chloride for paste containing a polymer having an average width of 0.1 to 10 μm of secondary particles using a vinyl chloride monomer, a polymerization initiator, an emulsifier, water and the like A method of obtaining paste polyvinyl chloride is used by preparing a base resin latex (hereinafter referred to as "vinyl chloride latex") and then spray drying the polyvinyl chloride latex using a spray dryer.

  On the other hand, hydrotalcite is a layered double hydroxide composed mainly of basic carbonates of divalent metals and trivalent metals. Hydrotalcite has high anion exchange capacity and is widely used as a highly safe biological stabilizer for vinyl chloride resins.

Heretofore, various proposals have been made to mix hydrotalcite at the time of production in order to improve the thermal stability of paste polyvinyl chloride. For example, Patent Document 1 proposes a vinyl chloride polymer composition in which the thermal stability is improved and the paste dispersion has a low viscosity. Specifically, in a composition comprising 0.05 to 5 parts by weight of hydrotalcites with respect to 100 parts by weight of a vinyl chloride polymer that can be pasted, the hydrotalcites of the general formula Mg _{1 −x} Al _x (OH) ₂ (CO ₃ ) _{x / 2} · mH ₂ O (wherein, m is a number satisfying 0 ≦ m <0.6 and x is a number satisfying 0 <x ≦ 0.32 respectively A vinyl chloride polymer composition has been proposed which is characterized by using the hydrotalcites represented by the formula. The hydrotalcites to be compounded are particularly preferably those in which the range of x is 0.30 ≦ x ≦ 0.32, the BET specific surface area is 30 m ² / g or less, and the decrystallization water treatment.

  Patent Document 2 proposes a method for producing a vinyl chloride polymer composition for the purpose of improving the thermal stability and the water absorption whitening property. Specifically, a paste-formable vinyl chloride-based polymer composition obtained by emulsion polymerization or fine suspension polymerization of vinyl chloride alone or a mixture of vinyl chloride and another monomer copolymerizable therewith is used. In the production method, as a means for containing the hydrotalcites, addition is made in the form of an aqueous slurry in which the hydrotalcites are dispersed in deionized water at any time before the initiation of the polymerization, during or after the polymerization reaction. A method of producing a vinyl chloride polymer composition is disclosed, which is characterized by using the following method.

  In Patent Document 3, a polyvinyl chloride resin composition for paste which can prevent bleeding to the surface when it is made into a polyvinyl chloride molded product and which can give a plastisol having good adhesion between layers in lamination, bonding, etc. Proposed. Specifically, to a vinyl chloride resin obtained by emulsion polymerization or fine suspension polymerization of a vinyl chloride monomer, 0.05 to 1 part by weight of hydrotalcite per 100 parts by weight of the resin, an alkylene group There is disclosed a vinyl chloride resin composition for paste containing 0.1 to 1 part by weight of a polyalkylene oxide having 2 to 4 carbon atoms, a plastisol obtained therefrom, and a laminate based thereon. In addition, when added to the latex as a method of adding hydrotalcite, the finely powdered hydrotalcite does not disperse uniformly in the latex (water) and may partially aggregate, so It is considered good to add as a slurry dispersed in water.

  As described above, although various proposals have been made to improve the thermal stability of paste polyvinyl chloride using hydrotalcite, there is still room for improvement in its thermal stability. Moreover, there existed a problem that transparency of the polyvinyl-chloride molded object using paste polyvinyl chloride fell by mix | blending hydrotalcite.

JP-A-2-123147 JP-A-2-110108 JP-A-9-77943

  An object of the present invention is to provide a paste polyvinyl chloride excellent in thermal stability and transparency when it is used as a floor material, a wallpaper, a foam sheet, and other polyvinyl chloride molded articles. More specifically, in the paste polyvinyl chloride production process, to prevent the thermal deterioration of the paste polyvinyl chloride at the time of spray drying, to improve the thermal stability of the polyvinyl chloride molded body, and also compared to when using the conventional hydrotalcite Improve the transparency of the polyvinyl chloride molded body.

  The present inventors synthesize hydrotalcite having a smaller primary particle size and better dispersibility than before, and add it in the suspension state at the time of polymerization of the vinyl chloride resin, whereby the thermal stability of the molded body is achieved. It has been found that paste polyvinyl chloride having high quality and transparency can be produced. Furthermore, it has been found that adding the hydrotalcite before spray drying increases the thermal stability of the formed body as compared to the case where it is added after spray drying.

That is, the present invention provides paste polyvinyl chloride which solved the above problems. Specifically, a vinyl chloride-based resin composition for paste containing 0.05 to 5 parts by weight of hydrotalcite represented by the following (formula 1) with respect to 100 parts by weight of vinyl chloride-based resin for paste The vinyl chloride resin composition for paste according to claim 1, wherein the hydrotalcite in the vinyl chloride resin composition for paste satisfies the following (A) and (B).
(M ²⁺ ) _1-X (M ³⁺ ) _X (OH) ₂ (A ^{n −} ) _{X / n} · _m H ₂ O (Equation 1)
(Wherein, M ²⁺ is at least one or more of divalent metals, M ³⁺ is at least one or more of trivalent metals, A ^{n −} is an n-valent anion, n is an integer of 1 to 6, and x And m are each in the range of 0.17 ≦ x ≦ 0.36, 0 ≦ m ≦ 10)
(A) The average width of the primary particles in the resin by the SEM method is 5 nm or more and 200 nm or less;
(B) Monodispersion degree in the resin represented by the following formula is 50% or more;
Degree of monodispersion in resin (%) = (average width of primary particles in resin by SEM method / average width of secondary particles in resin by SEM method) × 100

  The present invention includes the above method for producing paste polyvinyl chloride, a vinyl chloride plastisol containing the above-mentioned paste polyvinyl chloride and a plasticizer, and a polyvinyl chloride molded product comprising the vinyl chloride plastisol.

  The polyvinyl chloride molded article using the paste polyvinyl chloride of the present invention has high thermal stability and transparency as compared with conventional ones. The polyvinyl chloride plastisols containing the paste polyvinyl chloride of the present invention are suitably used for molding processes such as wallpaper, tile carpets, gloves, and undercoats for automobiles.

It is a schematic diagram explaining the width | variety about the primary particle of the hydrotalcite used by this invention. It is a schematic diagram explaining the width | variety about the secondary particle of the hydrotalcite used by this invention.

  Hereinafter, the present invention will be specifically described.

<Paste vinyl chloride>
The composition of the paste polyvinyl chloride of the present invention, the average particle diameter, the contained vinyl chloride resin for paste, and the contained hydrotalcite are as follows.

(Constitution)
The paste polyvinyl chloride of the present invention contains hydrotalcite in an amount of 0.05 parts by weight or more and less than 5 parts by weight with respect to 100 parts by weight of the vinyl chloride resin for paste. The lower limit of the content of hydrotalcite is more preferably 0.1 parts by weight, still more preferably 0.2 parts by weight with respect to 100 parts by weight of the vinyl chloride resin for paste. The upper limit of the content of hydrotalcite is more preferably 4 parts by weight, still more preferably 3 parts by weight with respect to 100 parts by weight of the vinyl chloride resin for paste. The paste polyvinyl chloride of the present invention is a vinyl chloride type paste for pastes such as a polymerization initiator, an emulsifier, an emulsifying aid, a buffer, a higher alcohol, a higher fatty acid, a higher fatty acid ester, a dispersing aid such as chlorinated paraffin, a polymerization degree regulator In the polymerization of the resin, it may contain substances generally added.

(Average particle size)
The paste polyvinyl chloride of the present invention has an average particle size (D50) in a dry particle size measurement method of 10 to 200 μm. The upper limit of the average particle size is preferably 190 μm, more preferably 180 μm, and still more preferably 170 μm. The lower limit of the average particle size is preferably 15 μm, more preferably 20 μm, and still more preferably 25 μm. If the average particle size is smaller than 10 μm, the viscosity becomes high when it is made into a vinyl chloride plastisol, and the handling property is unfavorably deteriorated. When the average particle size is larger than 200 μm, the dispersibility of paste polyvinyl chloride in the plasticizer is deteriorated when it is made into a vinyl chloride plastisol, which is not preferable.

(Vinyl chloride resin for paste)
The vinyl chloride-based resin for paste contained in the paste polyvinyl chloride of the present invention is polyvinyl chloride or a copolymer of vinyl chloride monomer and a monomer copolymerizable therewith. Examples of monomers copolymerizable with vinyl chloride include, but are not limited to, vinylidene chloride, ethylene, propylene, acrylonitrile, vinyl acetate, maleic acid, acrylic acid, acrylic acid ester and the like.

  The average degree of polymerization of the paste polyvinyl chloride of the present invention is preferably in the range of 400 to 4,000. When the degree of polymerization is less than 400, the thermal stability of the polymer is bad and it tends to be colored yellow. Also, the product strength may decrease. If the degree of polymerization is greater than 4,000, the foamability and the formability (gelling property) are adversely affected, and the productivity and the designability are likely to be deteriorated.

(Chemical formula of hydrotalcite)
The hydrotalcite of the present invention is represented by the following formula (1).
(M ²⁺ ) _1-X (M ³⁺ ) _X (OH) ₂ (A ^{n −} ) _{X / n} · mH ₂ O (1)
(Wherein, M ²⁺ is at least one or more of divalent metals, M ³⁺ is at least one or more of trivalent metals, A ^{n −} is an n-valent anion, n is an integer of 1 to 6, and x And m are each in the range of 0.17 ≦ x ≦ 0.36, 0 ≦ m ≦ 10)

(Type of metal of hydrotalcite)
In the hydrotalcite represented by the formula (1), M ²⁺ is at least one or more of divalent metals, and M ³⁺ is at least one or more of trivalent metals. The preferred divalent metal is one or more selected from the group consisting of Mg and Zn, and the preferred trivalent metal is Al. This is because the safety to the living body is high and the particles are white and versatile.

(Range of x in hydrotalcite)
In the hydrotalcite represented by the formula (1), the range of x is 0.17 ≦ x ≦ 0.36. A further preferable upper limit of x is 0.34. A further preferable lower limit of x is 0.19. When x exceeds 0.36, boehmite is by-produced, and conversely, when it is smaller than 0.17, magnesium hydroxide is by-produced, and in any case, when it is made a vinyl chloride resin composition, the transparency is lowered.

(M range of hydrotalcite)
In the hydrotalcite represented by the formula (1), the range of m is 0 ≦ m ≦ 10. A further preferable upper limit of m is 6.

(Type of interlayer anion of hydrotalcite)
In hydrotalcite represented by the formula (1) ^{represents A n-} is an n-valent anion, n is an integer of 1 to 6, respectively, preferred ^{A n-} is _CO ^{3 2-} and ClO ₄ ^- is selected from 1 It is more than a species.

(Grid distortion in the <003> direction of hydrotalcite)
In the hydrotalcite of the present invention, the lattice strain in the <003> direction in the X-ray diffraction method is 3 × 10 ⁻³ or less, preferably 2.5 × 10 ⁻³ or less, more preferably 2 × 10 ⁻³ or less It is. If the lattice strain in the <003> direction is larger than 3 × 10 ⁻³ , primary particles aggregate in the suspension and the resin, and the thermal stability and transparency of the vinyl chloride resin composition deteriorate.

(BET specific surface area of hydrotalcite)
In the hydrotalcite of the present invention, the BET specific surface area is 20 to 600 m ² / g. A more preferred upper limit to the BET specific surface area is 500 m ² / g, and more preferably 400 m ² / g. A more preferable lower limit of the BET specific surface area is 30 m ² / g, and further preferably 40 m ² / g. When the BET specific surface area is less than 20 m ² / g, the reactivity with free halogen and the dispersion of primary particles are not sufficient. On the other hand, if it is larger than 600 m ² / g, it is not preferable because the polyvinyl chloride resin composition tends to be colored.

(Definition of Hydrotalcite Primary Particles)
Primary particles are particles that have clear boundaries that can not be geometrically divided any more. FIG. 1 is a schematic view illustrating the width (W ₁ ) of primary particles used in the present invention. As shown in FIG. 1, the width W ₁ of primary particles is defined. That is, when the primary particles are in the form of a hexagonal plate, the major axis of the particles is the “width W _{1 of} primary particles”.

(Definition of secondary particles of hydrotalcite)
The secondary particles are particles in which a plurality of primary particles are gathered to form an aggregate. FIG. 2 is a schematic view illustrating the secondary particles used in the present invention and the lateral width (W ₂ ) of the secondary particles. As shown in FIG. 2, define the width W ₂ of the secondary particles. That is, the diameter of the sphere when it is considered that the secondary particles are encased in the sphere is “the lateral width W _{2 of the} secondary particle”.

(Average width of primary particles in hydrotalcite resin)
In the hydrotalcite of the present invention, the average width of primary particles in the resin according to the SEM method is 5 to 200 nm. The upper limit of the average width of the primary particles in the resin is preferably 180 nm, more preferably 150 nm, still more preferably 120 nm, still more preferably 100 nm, most preferably 60 nm. If the average width of the primary particles is larger than 200 nm, the transparency of the vinyl chloride resin composition is deteriorated. The average width of the primary particles is determined from the arithmetic mean of the measured values of the width of any 100 primary particles in the SEM photograph by the SEM method.

(Monodispersity of hydrotalcite in resin)
In the hydrotalcite of the present invention, the degree of monodispersion in the resin represented by the following formula is 50% or more, more preferably 60% or more, and still more preferably 80% or more. If the degree of monodispersion of hydrotalcite in the resin is less than 50%, the thermal stability and transparency of the vinyl chloride resin composition will deteriorate. The width of the primary particles in the resin and the width of the secondary particles in the resin are obtained from the arithmetic mean of the measured values of the widths of any 100 primary particles and secondary particles in the SEM photograph by the SEM method. I ask for each.
Monodispersion degree in resin (%) = (average width of primary particles in resin by SEM method / average width of secondary particles in resin by SEM method) × 100

<PVC plastisol>
(Constitution)
The vinyl chloride plastisols of the present invention include the paste polyvinyl chloride of the present invention and various additives such as a plasticizer, a filler, and a viscosity reducing agent.

(Plasticizer)
Examples of plasticizers include phthalates such as DOP (dioctyl phthalate) and DINP (diisononyl phthalate), which are general-purpose plasticizers, trimellitates, adipates, azelates and sebacates. Examples include ester-based, phosphate-based, polyester-based, epoxy-based, fatty acid-based, and pyromellitic acid-based plasticizers. The blending amount of the plasticizer is preferably 10 parts to 150 parts, more preferably 20 to 140 parts with respect to 100 parts by weight of paste polyvinyl chloride from the viewpoint of performance of the final product.

(Thickening agent)
In addition to the above components, a viscosity reducing agent may be used in the vinyl chloride plastisol of the present invention. Examples of the viscosity reducing agent include alkylbenzenes, mineral spirits, hydrocarbon-based compounds such as paraffin, higher alcohol fatty acid esters, sorbitan fatty acid esters, glycerin fatty acid esters and the like, but not limited thereto.

  In the vinyl chloride plastisols of the present invention, additives such as fillers, stabilizers, lubricants, antioxidants, ultraviolet absorbers, foaming agents, flame retardants, coloring agents and the like may be blended.

<PVC molding>
The present invention includes a molded polyvinyl chloride product comprising the vinyl chloride plastisol of the present invention.

<Production method of paste polyvinyl chloride>
The paste polyvinyl chloride of the present invention can be manufactured by a manufacturing method including the following (Step 1) to (Step 6).
(Step 1) A raw material preparation step of preparing a water-soluble composite metal salt aqueous solution and an alkali metal hydroxide aqueous solution. However, the water-soluble composite metal salt aqueous solution contains a divalent metal salt, a trivalent metal salt, and a monovalent organic acid and / or an organic acid salt which forms a complex with the trivalent metal.
(Step 2) A water-soluble complex metal salt aqueous solution and an alkali metal hydroxide aqueous solution prepared in (Step 1) are continuously reacted at a reaction temperature of 0 to 60 ° C. and a reaction pH of 8.5 to 11.5 to form hydrotalcite. A reaction step to obtain a suspension containing.
(Step 3) A washing step in which the suspension containing the hydrotalcite obtained in (Step 2) is dehydrated, then washed with water, and suspended in a water solvent.
(Step 4) A maturation step of stirring and holding the suspension containing hydrotalcite after washing obtained in (Step 3) at 0 to 100 ° C. for 1 to 60 hours.
(Step 5) A polymerization step of polymerizing a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and another monomer copolymerizable with vinyl chloride to obtain a vinyl chloride resin latex. However, the suspension containing the hydrotalcite prepared in (Step 4) is not less than 0.05 parts by weight and less than 5 parts by weight in solid content of the hydrotalcite per 100 parts by weight of the vinyl chloride resin. Before, during polymerization, it is added at any time after the end of polymerization.
(Step 6) A drying step of spray-drying the vinyl chloride resin latex obtained in (Step 5).

(Step 1: Raw material preparation process)
The raw materials of hydrotalcite are divalent metal salts, trivalent metal salts, monovalent organic acids and / or organic acid salts which form complexes with trivalent metals, and alkali metal hydroxide salts. Examples of divalent metal salts include water-soluble divalent metal salts such as magnesium chloride, magnesium bromide, magnesium nitrate, magnesium acetate, zinc chloride, zinc bromide, zinc nitrate, zinc acetate, etc. Absent. In order to prevent aggregation of primary particles, preferably, a divalent metal salt containing a monovalent anion is used. Two or more kinds of divalent metal salts can also be combined. Preferably, magnesium chloride and / or zinc chloride is used. Examples of trivalent metal salts include water-soluble trivalent metal salts such as aluminum chloride, aluminum bromide, aluminum nitrate and aluminum acetate, but not limited thereto. In order to prevent aggregation of primary particles, a trivalent metal salt preferably containing a monovalent anion is used. Two or more trivalent metal salts can also be combined. Preferably, aluminum chloride is used.

  In general, the precipitation pH of the trivalent metal ion as a hydroxide is lower than that of the divalent metal. Therefore, even if the pH at the time of reaction is kept constant by the pH adjuster, trivalent ions are first precipitated as hydroxide. From the difference between the precipitated pH of the divalent metal and the trivalent metal, a crystal strain is generated and aggregation of the primary hydrotalcite particles occurs.

  Therefore, by using a monovalent organic acid and / or an organic acid salt as a complexing agent and forming a complex with a trivalent metal, the precipitation pH of the trivalent metal ion as a hydroxide can be increased to obtain a divalent metal By bringing the pH close to the precipitation pH, hydrotalcite with less crystal distortion can be obtained. The complexing agent also has the effect of suppressing the crystal growth of primary particles of hydrotalcite by the steric hindrance effect of its molecule. Examples of monovalent organic acids and / or organic acid salts which form complexes with trivalent metals include lactic acid, sodium lactate, formic acid, sodium formate, acetic acid, sodium acetate, propionic acid and sodium propionate. It is not this limitation. Two or more organic acids and organic acid salts can also be combined. Preferably, lactic acid, sodium lactate, acetic acid and sodium acetate are used. Examples of the alkali metal hydroxide salt include sodium hydroxide and potassium hydroxide, but not limited thereto.

A divalent metal salt, a trivalent metal salt, and a monovalent organic acid and / or an organic acid salt forming a complex with a trivalent metal are dissolved in an aqueous solvent to prepare a water-soluble composite metal salt aqueous solution. The concentration of divalent metal in the water-soluble composite metal salt aqueous solution is 0.01 to 2 mol / L, preferably 0.1 to 1.5 mol / L. The concentration of the trivalent metal is 0.01 to 2 mol / L, preferably 0.1 to 1.5 mol / L. The concentration of the alkali metal hydroxide is 0.01 to 4 mol / L, preferably 0.1 to 2 mol / L. The ratio of divalent metal and trivalent metal is 1.78 ≦ M ²⁺ / M ³⁺ ≦ 4.88, preferably 1.94 ≦ M ²⁺ / M ³⁺ ≦ 4.26. The amount of addition of the monovalent organic acid and / or organic acid salt which forms a complex with the trivalent metal is 0.1 to 2.2 equivalents, preferably 0.3 to 2 equivalents, to the trivalent metal. is there. If it is less than 0.1 equivalent, the primary particles of hydrotalcite will be larger than 200 nm, which is not preferable. When it is more than 2.2 equivalents, the anion derived from the complexing agent enters between the layers of the hydrotalcite, and the swelling action unfavorably causes the suspension to gel.

(Step 2: Reaction step)
The hydrotalcites of the invention are produced in a continuous reaction. Since the ion concentration and pH in the solution can be kept uniform as compared with the batch reaction, hydrotalcite with less lattice distortion can be produced, and the production efficiency is better than the batch reaction.

  The concentration at the time of reaction is 0.1 to 300 g / L, preferably 0.5 to 250 g / L, and more preferably 1 to 200 g / L in terms of hydrotalcite. When the concentration at the time of reaction is lower than 0.1 g / L, productivity is low, and when it is higher than 300 g / L, primary particles are not preferable. The temperature at the time of reaction is 0 to 60 ° C, preferably 10 to 50 ° C, and more preferably 20 to 40 ° C. When the temperature at the time of reaction is lower than 0 ° C., it is not preferable because the suspension is frozen, and when higher than 60 ° C., it is not preferable because the primary particles become larger than 200 nm. The pH at the time of reaction is 8.5 to 11.5, preferably 8.8 to 11.0, and more preferably 9.1 to 10.5. When the pH at the time of reaction is lower than 8.5, the lattice distortion of hydrotalcite is increased, and the degree of monodispersion in the suspension and the resin is lowered. It is not preferable because the primary particles of hydrotalcite become larger than 200 nm.

(Step 3: Cleaning step)
The suspension containing hydrotalcite prepared in the above (Step 2) is dehydrated and then washed with water 20 to 30 times the weight of hydrotalcite in deionized water, and resuspended in deionized water. Through this step, salts such as sodium can be removed to prevent aggregation of primary particles during the aging step.

  In the washing step, after dehydration, ion exchange can be performed with any anion prior to water washing. There are two ways of ion exchange. The first method is a method of dehydrating the suspension containing hydrotalcite after reaction to form a cake, dispersing it in ion-exchanged water, adding an anion-containing aqueous solution, and maintaining stirring. At this time, the equivalent of the anion is 1 to 5 equivalents, more preferably 1.5 to 3 equivalents with respect to hydrotalcite. The temperature for stirring and holding is preferably 30 to 90 ° C., more preferably 50 to 80 ° C. The hydrotalcite concentration is preferably 0.1 to 300 g / L, more preferably 0.5 to 250 g / L, still more preferably 1 to 200 g / L, in terms of hydrotalcite.

  The second method of ion exchange is a method in which the suspension containing hydrotalcite after reaction is dehydrated and caked, and then an anion-containing aqueous solution is directly added. At this time, the addition amount of the anion is 1 to 5 equivalents, preferably 1.5 to 3 equivalents with respect to hydrotalcite.

(Step 4: Aging step)
The suspension containing the hydrotalcite prepared in the above (Step 3) is kept stirring at 0 to 100 ° C. for 1 to 60 hours. Through this process, the aggregation of primary particles can be alleviated, and a suspension in which the primary particles are sufficiently dispersed can be obtained. When the aging time is less than 1 hour, it is not sufficient as a time to reduce the aggregation of primary particles. Aging for longer than 60 hours does not make sense because there is no change in the aggregation state. The preferred ripening time is 2 to 30 hours, more preferably 4 to 24 hours. If the aging temperature is higher than 100 ° C., it is not preferable because the primary particles become larger than 200 nm. When the aging temperature is less than 0 ° C., the suspension is not preferable because it freezes. The preferred ripening temperature is 20 to 90 ° C, more preferably 40 to 80 ° C. The concentration upon ripening is 0.1 to 300 g / L, preferably 0.5 to 250 g / L, and more preferably 1 to 200 g / L in terms of hydrotalcite. When the concentration at the time of ripening is lower than 0.1 g / L, productivity is low, and when it is higher than 300 g / L, primary particles are not preferable.

(Step 5: polymerization step)
Vinyl chloride alone or a mixture of vinyl chloride and a monomer copolymerizable therewith is polymerized by an emulsion polymerization method or a fine suspension polymerization method. Examples of monomers copolymerizable with vinyl chloride include, but are not limited to, vinylidene chloride, ethylene, propylene, acrylonitrile, vinyl acetate, maleic acid, acrylic acid, acrylic acid ester and the like. In the aqueous medium, the vinyl chloride monomer in the presence of an emulsifier and a water-soluble polymerization initiator, and in the fine suspension polymerization, the vinyl chloride monomer in an aqueous medium, the presence of an emulsifier and an oil-soluble polymerization initiator It is carried out by polymerizing under the homogenization treatment below.

  As an emulsifier used for the emulsion polymerization method, for example, higher alcohol sulfuric acid ester salt (alkali metal salt, ammonium salt), alkylbenzene sulfonate (alkali metal salt, ammonium salt), higher fatty acid salt (alkali metal salt, ammonium salt) Other anionic surfactants, nonionic surfactants, and / or cationic surfactants may be mentioned. These surfactants may be used alone or in combination of two or more. The amount of the emulsifier used is in the range of 0.1 to 3% by weight, more preferably 0.3 to 1% by weight, based on the vinyl chloride monomer, but is not particularly limited.

  These emulsifiers may be additionally used for adjusting the foaming property at the time of processing, and may be added after completion of the polymerization reaction separately from the emulsifier for polymerization at this time. The polymerization initiator may be one generally used in each polymerization method of vinyl chloride monomers, and is not particularly limited. For example, as a polymerization initiator used in the emulsion polymerization method, a persulfate (sodium salt, potassium salt, ammonium salt), a water-soluble peroxide such as hydrogen peroxide, or a water-soluble peroxide thereof There may be mentioned water-soluble redox initiators which consist of a combination with water-soluble reducing agents (eg sodium sulfite, sodium metabisulfite, sodium bisulfite, ascorbic acid, sodium formaldehyde sulfoxylate etc).

  In addition, as a polymerization initiator used in the fine suspension polymerization method, monomers soluble such as azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile), lauroyl peroxide, t-butylperoxypivalate, etc. Examples are oil-soluble initiators, or redox type initiators consisting of a combination of these oil-soluble initiators and the above-mentioned water-soluble reducing agent.

  These polymerization initiators can be used alone or in combination of two or more. The amount of polymerization initiator used varies depending on the type of initiator, polymerization temperature, desired reaction time, etc., but is generally 0.01 to 1% by weight based on the total amount of vinyl chloride monomers. Furthermore, in polymerization of vinyl chloride monomers, various polymerizations such as polymerization degree regulators (chain transfer agents, crosslinking agents), antioxidants, pH adjusters, activators of redox initiators, etc., as necessary. An auxiliary agent can be added as appropriate, and the kind, amount of preparation, etc. of each of these components may be a general one which is conventionally practiced in the polymerization of vinyl chloride monomers.

  In addition, as a polymerization degree regulator used for the polymerization of the vinyl chloride monomer, a chain transfer agent such as trichloroethylene, carbon tetrachloride, 2-mercaptoethanol, octylmercaptan, etc., diallyl phthalate, triallyl isocyanurate, ethylene glycol Crosslinking agents such as diacrylate and trimethylolpropane trimethacrylate are exemplified.

  Before the start of the polymerization, during the polymerization or at any time after the completion of the polymerization reaction, the hydrotalcite suspension after the aging treatment prepared in the above (Step 4) is added. It is preferable to add after completion of the polymerization so as not to affect the dispersion stability and particle formation during the polymerization. By adding the hydrotalcite suspension after aging, the primary particles are sufficiently dispersed in paste polyvinyl chloride, and the thermal stability and transparency of the polyvinyl chloride molded article become remarkably high. Moreover, the thermal deterioration of paste polyvinyl chloride at the time of spray drying can be prevented by adding hydrotalcite before spray drying.

  The amount of hydrotalcite added is 0.05 parts by weight or more and less than 5 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. The lower limit of the content of hydrotalcite is more preferably 0.1 parts by weight, still more preferably 0.2 parts by weight with respect to 100 parts by weight of the vinyl chloride resin for paste. The upper limit of the content of hydrotalcite is more preferably 4 parts by weight, still more preferably 3 parts by weight with respect to 100 parts by weight of the vinyl chloride resin for paste.

(Step 6: Drying step)
The polyvinyl chloride latex produced in (Step 5) is dried by spray drying. The dryer used for spray drying is not particularly limited. The drying air inlet temperature and the drying air outlet temperature are not particularly limited, but the drying air inlet temperature is preferably 80 to 400 ° C., and the drying air outlet temperature is preferably 50 to 200 ° C. The drying air inlet temperature is more preferably 200 to 350 ° C., and the drying air outlet temperature is more preferably 80 to 130 ° C. By spray drying, granular paste polyvinyl chloride having an average particle diameter of 10 to 200 μm in a dry particle size measuring method can be obtained. If the paste polyvinyl chloride after spray drying contains water, it may be additionally hot air dried.

  In order to reduce coarse particles in paste polyvinyl chloride, it is preferable to carry out coarse particle removal with a sieve on the obtained paste polyvinyl chloride. The sieve may be a commonly used sieve, and examples thereof include a vibrating sieve, an ultrasonic vibrating sieve, a three-dimensional vibrating sieve, a net surface fixed type air classifier and the like, which may be used alone or in combination. A plurality of different ones can be used in combination.

  Also, coarse particles in the latex may be removed prior to spray drying of the vinyl latex. As a device for removing coarse particles, for example, generally used devices such as a wet vibration sieve, a wet centrifuge, a liquid cyclone and the like can be used, but from the point of coarse particle removal efficiency and throughput Vibrating sieves are preferred.

  Furthermore, in order to increase the drying efficiency, the polyvinyl chloride latex may be concentrated and then spray dried. As a concentration device, known ones such as an ultrafiltration membrane, a vacuum evaporator, and a thin film evaporator may be used alone or in combination.

  A liquid caking agent can also be added prior to spray drying the PVC latex. Here, the liquid caking agent is to improve the dispersibility of the obtained granules in the plasticizer, and examples thereof include polyhydric alcohols and / or ether compounds of polyhydric alcohols. For example, ethylene glycol diether compounds such as ethylene glycol, ethylene glycol dibenzyl ether, ethylene glycol dibutyl ether, ethylene glycol diethyl ether, ethylene glycol dimethyl ether, ethylene glycol monobenzyl ether, ethylene glycol mono n-butyl ether, ethylene glycol monoethyl Ethers, monoether compounds such as ethylene glycol monomethyl ether, etc. may be mentioned.

<Method of producing polyvinyl chloride plastisol>
The polyvinyl chloride plastisols according to the present invention are obtained by adding the above-described plasticizer and, if necessary, other compounding agents to paste polyvinyl chloride, using a ribbon blender, a super mixer, a Hobart mixer, a disperser, a dissolver, etc. It can be manufactured.

  EXAMPLES The present invention will be described in detail by way of examples, but the present invention is not limited to these examples. In the examples, each physical property was measured by the following method.

(A) Average Width of Hydrotalcite Primary and Secondary Particles in Resin The cross section of paste polyvinyl chloride was polished using a cross section polisher (IB-09010 CP, manufactured by JEOL Ltd.). Using a scanning electron microscope (SEM) (JSM-7600F, JEOL Ltd.), observe the cross section of the resin after polishing, measure the width of the primary and secondary particles of any 100 crystals, and calculate its arithmetic The average was taken as the average width in the resin of primary particles and secondary particles.

(B) Degree of monodispersity of hydrotalcite in resin Based on the following formula, it was calculated from the value of the above (A).
Monodispersity in resin (%) = (average width of primary particles in resin by SEM method / average width of secondary particles in resin by SEM) × 100

(C) Crystal strain in the <003> direction of hydrotalcite The aqueous suspension containing the hydrotalcite prepared in the above (Step 4) is dehydrated, vacuum dried, and then crushed to prepare a measurement sample.
(Sine θ / λ) is plotted on the horizontal axis and (β cos θ / λ) on the vertical axis according to the relational expression of (Equation 2), the crystal grain size (g) and the gradient (1/2) from the reciprocal of the intercept Crystal strain (() was determined by multiplication.
(Β cos θ / λ) = (1 / g) + 2η × (sin θ / λ) (Expression 2)
(Where λ represents the wavelength of the X-ray used and is 1.542 Å for the Cu-Kα ray. Θ represents the Bragg angle, β represents the true half width (unit: radian).)
The above β was determined by the following method.
The diffraction profiles of the (003) plane and the (006) plane were measured using an X-ray diffractometer (Empyrean, manufactured by PANalytical) using Cu-Kα rays generated under conditions of 45 KV and 40 mA as an X-ray source. . Measurement conditions are 10 ° / min at gonio speed, slit width in the order of divergence slit, receiving slit and scattering slit, and for (003) plane, 1 °-0.3 mm-1 °, (006) plane Was measured under the conditions of 2 ° -0.3 mm-2 °. For the obtained profile, the width (B ₀ ) at (1/2) of the height from the background to the diffraction peak was measured. From the relationship between the split width (δ) of K _α1 and K _α2 with respect to 2θ, δ with respect to 2θ of (003) plane and (006) plane was read. Next, B was determined from the relationship between (δ / B ₀ ) and (B / B ₀ ) based on the values of B ₀ and δ. Subsequently, with respect to high purity silicon (purity 99.999%), each diffraction profile was measured at slit width (1/2) °-0.3 mm-(1/2) ° to obtain half width (b) . This was plotted against 2θ to create a graph showing the relationship between b and 2θ. (B / β) was determined from b corresponding to 2θ of the (003) plane and the (006) plane. Β was determined from the relationship between (b / B) and (β / B).

(D) BET Method Specific Surface Area of Hydrotalcite The aqueous suspension containing the hydrotalcite prepared in the above (Step 4) was dehydrated, vacuum dried, and then pulverized to obtain a measurement sample. The specific surface area of the dried sample was measured by a gas adsorption method using a specific surface area measuring device (NOVA 2000, manufactured by Yuasa Ionics).

(E) Determination of Chemical Composition of Hydrotalcite The aqueous suspension containing the hydrotalcite prepared in the above (Step 4) was dehydrated, vacuum dried, and then pulverized to obtain a measurement sample. After heating and dissolving the sample in nitric acid, Mg, Zn and Al were quantified by chelate titration, and Cl was quantified by Forhardt titration. CO ₃ is JIS. R. Based on 9101, it quantified with AGK type CO ₂ simple accurate quantitative determination device. Interlayer water was calculated from weight loss using TG-DTA.

(F) Thermal Stability of PVC Molding The sample PVC plastisol was applied onto an aluminum foil so as to have a thickness of 1 mm after heating. The coated film was heat-treated at 195 ° C. for 5 minutes and then cut into 4 cm wide and 4 cm wide sheets. Subsequently, the sheet was heated at 195 ° C., the heating time was taken out every 5 minutes, and the time until coloring to red to blackish brown was visually confirmed. The longer the time to coloring, the better the thermal stability.

(G) Transparency of a PVC Molding The sample vinyl plastisol was applied onto an aluminum foil so that the thickness after heating was 1 mm. The coated film was heat-treated at 195 ° C. for 5 minutes and then cut into 4 cm wide and 4 cm wide sheets. Three sheets were prepared, stacked in a mold of 2 mm in thickness, sandwiched between stainless steel plates from the top and bottom, pressed with a press (ANSF-50HH / C, manufactured by Shinto Metal Industry Co., Ltd.) at 200 ° C for 10 minutes at 100 MPa , Test pieces were made. The haze (haze degree) of the produced test piece is measured according to JIS. K. Based on 7136, it measured by haze meter (automatic haze meter TC-H3DP, Tokyo Denshoku make), and evaluated transparency. The lower the haze, the better the transparency.

(Step 1: Raw material adjustment step)
Magnesium chloride hexahydrate (Wako Pure Chemical Industries, Ltd.) and aluminum chloride hexahydrate (Wako Pure Chemical Industries, Ltd.) were dissolved in deionized water to obtain an aqueous solution of 0.2 mol / L of magnesium and 0.1 mol / L of aluminum. To this aqueous solution, 1.75 equivalents of sodium lactate (Kishida Chemical) was added to aluminum to obtain a water-soluble composite metal salt aqueous solution. On the other hand, sodium hydroxide (Wako Pure Chemical Industries, Ltd.) was dissolved in deionized water so as to be 0.8 mol / L to prepare an alkali metal hydroxide aqueous solution.

(Step 2: Reaction step)
The flow rate of the water-soluble composite metal salt aqueous solution is set to 120 mL / min, the flow rate of the alkali metal hydroxide aqueous solution is set to 95 mL / min, and each is poured into a cylindrical reaction tank having an overflow volume of 215 mL to continuously react. went. The suspension overflowed from the reaction vessel as an overflow was collected, and the flow rate of the aqueous alkali metal hydroxide solution was adjusted so that the pH was 9.3 to 9.6. During the reaction, the temperature of the raw material and the reaction tank were adjusted so that the reaction temperature became 25 ° C. During the reaction, stirring was performed at a rotational speed of 1000 rpm using a screw propeller having a diameter of 2.5 cm.

(Step 3: Cleaning step)
The suspension was dewatered by suction filtration using a round Nutche and a suction filter bottle to form a cake. Next, 1.5 equivalents of sodium carbonate aqueous solution was poured into the cake with respect to aluminum of hydrotalcite contained in the cake, and ion exchange was performed. Next, the ion-exchanged cake was washed with water using deionized water of 30 mass times that of hydrotalcite in order to remove by-products such as salts and impurities such as residual sodium carbonate.

(Step 4: Aging step)
The water washed cake was resuspended in deionized water. Resuspension was performed for 20 minutes at a rotational speed of 4000 rpm using a homomixer. Deionized water was poured into the resuspended suspension to adjust the concentration to 50 g / L. The suspension after concentration adjustment was kept at 60 ° C. in a thermostat, and aging treatment was performed for 24 hours to obtain a suspension of hydrotalcite A. The production conditions of hydrotalcite A are shown in Table 1, and the chemical composition of Hydrotalcite A, the crystal strain in the <003> direction, and the BET specific surface area are shown in Table 2.

(Step 5: polymerization step)
90 kg of deionized water and 60 g of sodium metabisulfite are charged into a 200-liter polymerization vessel equipped with a stirrer and degassed, and then 60 kg of vinyl chloride monomer is charged, and a 0.2% aqueous solution of potassium persulfate is about 10 ml / min. The polymerization was carried out at 50.degree. C. to prepare a latex of a seed polymer having an average particle diameter of 0.48 .mu.m.

Next, 80 kg of deionized water, 15 g of sodium lauryl sulfate, 90 g of ammonium sulfite, and 4.5 kg of the seed latex prepared above as solid components are charged into a 200 l polymerizer equipped with a stirrer, and after deaeration, vinyl chloride monomer 75 .5 kg were charged, and 10 liters of 0.4% aqueous ammonium persulfate solution and 6 liters of aqueous ammonium myristate solution were continuously added, and polymerization was carried out at 47 ° C. When the reaction rate reached 12%, 100 g of a polymerization degree regulator (diallyl phthalate) was injected into the system. When the internal pressure of the polymerization vessel dropped to 1 kg / cm ² from the saturated vapor pressure of the vinyl chloride monomer at 47 ° C., the unreacted monomer was released out of the system to stop the reaction. The average degree of polymerization of the vinyl chloride resin was 2,500.

  In the vinyl chloride resin latex obtained as described above, the suspension of the hydrotalcite after ripening obtained in (Step 4) under stirring is a solid content with respect to 100 parts by weight of the vinyl chloride resin in the latex. 0.5 parts by weight was added.

(Step 6: Drying step)
The vinyl chloride latex obtained in (Step 5) was spray-dried by a nozzle method using a spray dryer to obtain paste polyvinyl chloride A of the present invention. The temperature in the drying chamber was set to have an inlet temperature of 250 ° C. and an outlet temperature of 90 ° C. The average particle size of paste polyvinyl chloride A, the average width of primary particles in the hydrotalcite resin, the average width of secondary particles in the resin, and the degree of monodispersion in the resin are shown in Table 3.

  A hydrotalcite was produced in the same manner as in the ripening step of Example 1 except that the ripening temperature was set to 90 ° C., and a suspension of hydrotalcite B was obtained. The subsequent steps were performed in the same manner as in Example 1 to obtain paste polyvinyl chloride B of the present invention. The production conditions of hydrotalcite B are shown in Table 1, the chemical composition of hydrotalcite B, the crystal strain in the direction of <003>, the BET specific surface area in Table 2, the average particle diameter of paste polyvinyl chloride B, the resin of hydrotalcite Table 3 shows the average width of primary particles, the average width of secondary particles in resin, and the degree of monodispersion in resin.

  In the washing step of Example 1, in place of the aqueous sodium carbonate solution, 1.5 equivalents of an aqueous sodium perchlorate solution was added to the cake with respect to the aluminum of hydrotalcite contained in the cake, and ion exchange was performed. A sample was prepared in the same manner, except that a suspension of hydrotalcite C was obtained. The subsequent steps were performed in the same manner as in Example 1 to obtain paste polyvinyl chloride C of the present invention. The production conditions of Hydrotalcite C are shown in Table 1, the chemical composition of Hydrotalcite C, the crystal strain in the <003> direction, the BET specific surface area in Table 2, the average particle diameter of paste PVC C, the resin of hydrotalcite Table 3 shows the average width of primary particles, the average width of secondary particles in resin, and the degree of monodispersion in resin.

  In the raw material preparation step of Example 1, magnesium chloride hexahydrate (Wako Pure Chemical Industries, Ltd.) and aluminum chloride hexahydrate (Wako Pure Chemical Industries) are added, and zinc chloride (Wako Pure Chemical Industries, Ltd.) is dissolved in deionized water, An aqueous solution of 0.15 mol / L of magnesium, 0.05 mol / L of zinc and 0.1 mol / L of aluminum was obtained. To this aqueous solution, 1.75 equivalents of sodium lactate (Kishida Chemical) was added with respect to aluminum to obtain a water-soluble composite metal salt aqueous solution. On the other hand, sodium hydroxide (Wako Pure Chemical Industries, Ltd.) was dissolved in deionized water so as to be 0.8 mol / L to prepare an alkali metal hydroxide aqueous solution. The subsequent steps were carried out in the same manner to prepare a sample to obtain a suspension of hydrotalcite D. The subsequent steps were performed in the same manner as in Example 1 to obtain paste vinyl chloride D of the present invention. The production conditions of hydrotalcite D are shown in Table 1, the chemical composition of hydrotalcite D, the crystal strain in the <003> direction, the BET specific surface area in Table 2, the average particle diameter of paste polyvinyl chloride D, the resin of hydrotalcite Table 3 shows the average width of primary particles, the average width of secondary particles in resin, and the degree of monodispersion in resin.

(Comparative example 1)
A sample was prepared in the same manner as in the raw material preparation step of Example 1 except that sodium lactate was not added, and a suspension of hydrotalcite E was obtained. The subsequent steps were performed in the same manner as in Example 1 to obtain paste polyvinyl chloride E. The production conditions of hydrotalcite E are shown in Table 1, the chemical composition of hydrotalcite E, the crystal strain in the direction of <003>, the BET specific surface area in Table 2, the average particle diameter of paste polyvinyl chloride E, the resin of hydrotalcite Table 3 shows the average width of primary particles, the average width of secondary particles in resin, and the degree of monodispersion in resin.

(Comparative example 2)
A sample was prepared in the same manner as in Example 1 except that aging was carried out at 120 ° C. for 24 hours using an autoclave to obtain a suspension of hydrotalcite F. The subsequent steps were performed in the same manner as in Example 1 to obtain paste polyvinyl chloride F. The production conditions of hydrotalcite F are shown in Table 1, the chemical composition of hydrotalcite F, the crystal strain in the <003> direction, the BET specific surface area in Table 2, the average particle diameter of paste PVC F, the resin of hydrotalcite Table 3 shows the average width of primary particles, the average width of secondary particles in resin, and the degree of monodispersion in resin.

(Comparative example 3)
A sample was prepared in the same manner as in the aging step of Example 1 except that aging was eliminated, and a suspension of hydrotalcite G was obtained. The subsequent steps were performed in the same manner as in Example 1 to obtain paste polyvinyl chloride G. The production conditions of hydrotalcite G are shown in Table 1, the chemical composition of hydrotalcite G, the crystal strain in the <003> direction, the BET specific surface area in Table 2, the average particle diameter of paste PVC G, the resin of hydrotalcite Table 3 shows the average width of primary particles, the average width of secondary particles in resin, and the degree of monodispersion in resin.

(Comparative example 4)
In the ripening step of Example 1, the suspension of hydrotalcite after the ripening treatment was dewatered, vacuum dried, and then pulverized to obtain a powder of hydrotalcite H. Thereafter, in the polymerization step, 0.5 parts by weight of the powder of hydrotalcite H obtained above was added to the vinyl chloride resin latex under stirring with respect to 100 parts by weight of the vinyl chloride resin in the latex. The subsequent steps were carried out in the same manner to obtain paste polyvinyl chloride H. The average particle size of paste polyvinyl chloride H, the average width of the primary particles in the hydrotalcite resin, the average width of the secondary particles in the resin, and the degree of monodispersion in the resin are shown in Table 3, respectively.

(Comparative example 5)
A sample was prepared in the same manner as Example 1 except that synthesis of hydrotalcite was omitted and no hydrotalcite was added during the polymerization step to obtain paste vinyl chloride I. The average particle size of paste polyvinyl chloride I is shown in Table 3.

  From Tables 1 and 2, it is understood that the hydrotalcites of Examples 1 to 4 have smaller lattice strain in the <003> direction and larger BET specific surface area than Comparative Examples 1 to 3.

  Table 3 shows that the hydrotalcite contained in the paste polyvinyl chloride of Examples 1 to 4 has a small average width of primary particles in the resin and a high degree of monodispersion. The hydrotalcites of Comparative Examples 1, 3 and 4 have a small average width of primary particles in paste polyvinyl chloride but a low degree of monodispersion. The hydrotalcite of Comparative Example 2 has a high degree of monodispersion in paste polyvinyl chloride, but the average width of primary particles is large.

<Production of PVC plastisols>
Using the paste polyvinyl chloride A prepared in Example 1, the vinyl chloride polyplatin of the present invention was prepared according to the following formulation. In addition, the Hobart mixer (Hobar Mixer N-50 type | mold, THE HOBART MFG. Co. make) was used for adjustment. The results of the thermal stability test and the transparency test are shown in Table 4.
(Blended)
Paste PVC sample: 100 parts by weight DOP (dioctyl phthalate): 60 parts by weight Ba-Zn based stabilizer (AC-118, manufactured by ADEKA): 1 part by weight

  Using the paste polyvinyl chloride B prepared in Example 2, the vinyl chloride plastisol of the present invention was prepared in the same manner as in Example 5. The results of the thermal stability test and the transparency test are shown in Table 4.

  Using the paste polyvinyl chloride C prepared in Example 3, the vinyl chloride plastisol of the present invention was prepared in the same manner as in Example 5. The results of the thermal stability test and the transparency test are shown in Table 4.

  Using the paste polyvinyl chloride D prepared in Example 4, the vinyl chloride plastisol of the present invention was prepared in the same manner as in Example 5. The results of the thermal stability test and the transparency test are shown in Table 4.

(Comparative example 6)
Using the paste polyvinyl chloride E prepared in Comparative Example 1, a vinyl chloride plastisol was prepared in the same manner as in Example 5. The results of the thermal stability test and the transparency test are shown in Table 4.

(Comparative example 7)
Using the paste polyvinyl chloride F prepared in Comparative Example 2, a polyvinyl chloride plastisol was prepared in the same manner as in Example 5. The results of the thermal stability test and the transparency test are shown in Table 4.

(Comparative example 8)
Using the paste polyvinyl chloride G prepared in Comparative Example 3, a polyvinyl chloride plastisol was prepared in the same manner as in Example 5. The results of the thermal stability test and the transparency test are shown in Table 4.

(Comparative example 9)
Using the paste polyvinyl chloride H prepared in Comparative Example 4, polyvinyl chloride plastisol was prepared in the same manner as in Example 5. The results of the thermal stability test and the transparency test are shown in Table 4.

(Comparative example 10)
Using the paste polyvinyl chloride I prepared in Comparative Example 5, a vinyl chloride plastisol was prepared in the same manner as in Example 5. The results of the thermal stability test and the transparency test are shown in Table 4.

(Comparative example 11)
Using the paste salt vinyl chloride I prepared in Comparative Example 5 and the powdered hydrotalcite H prepared in Comparative Example 4, a vinyl chloride plastisol was prepared according to the following formulation. In addition, the Hobart mixer (Hobar Mixer N-50 type | mold, THE HOBART MFG. Co. make) was used for adjustment. The results of the thermal stability test and the transparency test are shown in Table 4.
(Blended)
Paste PVC sample: 99.5 parts by weight DOP (dioctyl phthalate): 60 parts by weight Ba-Zn based stabilizer (AC-118, manufactured by ADEKA): 1 part by weight Powdered hydrotalcite: 0.5 parts by weight

  From Table 4, it can be seen that the polyvinyl chloride moldings of Examples 5 to 8 are superior in both thermal stability and transparency as compared with Comparative Examples 6 to 11.

  The polyvinyl chloride molded article using the paste polyvinyl chloride of the present invention has high thermal stability and transparency as compared with conventional ones. The polyvinyl chloride plastisols containing the paste polyvinyl chloride of the present invention are suitably used for molding processes such as wallpaper, tile carpets, gloves, and undercoats for automobiles.

Claims (7)

It is a vinyl chloride resin composition for paste containing 0.05 to 5 parts by weight of hydrotalcite represented by the following (formula 1) to 100 parts by weight of vinyl chloride resin for paste, A vinyl chloride resin composition for paste, wherein the hydrotalcite in the vinyl chloride resin composition for paste satisfies the following (A) and (B).
(M ²⁺ ) _1-X (M ³⁺ ) _X (OH) ₂ (A ^{n −} ) _{X / n} · _m H ₂ O (Equation 1)
(Wherein, M ²⁺ is at least one or more of divalent metals, M ³⁺ is at least one or more of trivalent metals, A ^{n −} is an n-valent anion, n is an integer of 1 to 6, and x And m are each in the range of 0.17 ≦ x ≦ 0.36, 0 ≦ m ≦ 10)
(A) The average width of the primary particles in the resin by the SEM method is 5 nm or more and 200 nm or less;
(B) Monodispersion degree in the resin represented by the following formula is 50% or more;
Degree of monodispersion in resin (%) = (average width of primary particles in resin by SEM method / average width of secondary particles in resin by SEM method) × 100 The polyvinyl chloride resin composition for paste according to claim 1, wherein the hydrotalcite according to claim 1 has a lattice strain of 3 × 10 ^-3 or less in the <003> direction according to X-ray diffraction method. The polyvinyl chloride resin composition for paste according to claim 1, wherein in the hydrotalcite according to claim 1, M 2 ⁺ is at least one selected from the group consisting of Mg and Zn, and M ^{3 +} is Al. . The polyvinyl chloride resin composition for paste according to claim 1, wherein the BET specific surface area of the hydrotalcite according to claim 1 is 20 to 600 m ² / g. A vinyl chloride-based plastisol comprising the vinyl chloride-based resin composition for paste according to claim 1 and a plasticizer. A vinyl chloride resin molded article comprising the vinyl chloride plastisol according to claim 5. The manufacturing method of the vinyl chloride-type resin composition for pastes containing the following six processes.
(Step 1) A raw material preparation step of preparing a water-soluble composite metal salt aqueous solution and an alkali metal hydroxide aqueous solution. However, the water-soluble composite metal salt aqueous solution contains a divalent metal salt, a trivalent metal salt, and a monovalent organic acid and / or an organic acid salt which forms a complex with the trivalent metal.
(Step 2) A water-soluble complex metal salt aqueous solution and an alkali metal hydroxide aqueous solution prepared in (Step 1) are continuously reacted at a reaction temperature of 0 to 60 ° C. and a reaction pH of 8.5 to 11.5 to form hydrotalcite. A reaction step to obtain a suspension containing.
(Step 3) A washing step in which the suspension containing the hydrotalcite obtained in (Step 2) is dehydrated, then washed with water, and suspended in a water solvent.
(Step 4) A maturation step of stirring and holding the suspension containing hydrotalcite after washing obtained in (Step 3) at 0 to 100 ° C. for 1 to 60 hours.
(Step 5) A polymerization step of polymerizing a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and another monomer copolymerizable with vinyl chloride to obtain a vinyl chloride resin latex. However, the suspension containing the hydrotalcite prepared in (Step 4) is not less than 0.05 parts by weight and less than 5 parts by weight in solid content of the hydrotalcite per 100 parts by weight of the vinyl chloride resin. Before, during polymerization, it is added at any time after the end of polymerization.
(Step 6) A drying step of spray-drying the vinyl chloride resin latex obtained in (Step 5).

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