JP2003231786A - Vinyl chloride polymer composition, manufacturing method thereof, and molding formed therefrom - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vinyl chloride polymer composition which gives excellent toughness in such breakdown mode as crack propagation at a long-term use, while maintaining high elastic modulus characteristic of a vinyl chloride polymer and without damaging tensile elongation characteristics, to provide its manufacturing method, and to provide a molding obtained from the composition. <P>SOLUTION: In the composition, (A) the vinyl chloride polymer has an average degree of polymerization of 600 or more, (B) a stratified swelling silicate is the one in which part of exchangeable inorganic cations present between the layers is substituted by organic cations, (C) the stratified swelling silicate dispersed in the composition has an average layer thickness of 0.5-50 nm and an average aspect ratio (ratio of layer length and layer thickness) of 10 or more, and (D) the stratified swelling silicate leaves 0.05-0.7 wt.% of the composition as the residue when the composition is completely burned at 950°C. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vinyl chloride polymer composition capable of obtaining a molded article having an excellent fracture toughness value while maintaining a high elastic modulus and not impairing tensile elongation characteristics, a method for producing the same, and a method for producing the same. It relates to a molded article obtained from the composition.

[0002]

BACKGROUND OF THE INVENTION Vinyl chloride polymers and compositions thereof are
It has been widely used in the fields of pipes, window frames, flat plates, sheets and the like by extrusion molding and the like because it is excellent in rigidity, weather resistance, flame retardancy, etc. and is relatively inexpensive. Among them, in the use of pipes, long-term durability of pipes such as crack progress during long-time use due to fine cracks generated during use or construction has become a problem. It is known that improving the toughness of a molded product, that is, improving the fracture toughness value is effective for improving long-term durability.

The fracture toughness value is a value for evaluating the difficulty of crack propagation due to stress concentration near the notch when a load is applied to a molded product for a long time, and is evaluated by, for example, a three-point bending test. In some cases, the fracture toughness value Kc is calculated from the maximum stress at fracture. Further, in the case of evaluation by the creep test, the fracture toughness value Kc is calculated from the magnitude of the load required to break in a certain time. Therefore,
In order to improve the fracture toughness value, the magnitude of the stress necessary for crack propagation is important, and a material having both ductility and rigidity is required rather than simply ductile material.

In JP-A-4-500402, as a method for improving the fracture toughness of vinyl chloride plastic pipes, a small amount of chlorinated polyethylene or other fracture performance agent (stretchability imparting agent in a vinyl chloride polymer) is used. ) Is disclosed. Also, Japanese Patent Laid-Open No. 2000-319479
The publication discloses a technique of adding a small amount of a rubber component to a vinyl chloride polymer as a method for improving the fracture toughness of a vinyl chloride polymer composition. These techniques promote the improvement of the fracture toughness value of vinyl chloride polymer,
It is necessary to uniformly disperse a small amount of the agent for destructive performance or the rubber component in the vinyl chloride polymer, and in order to disperse it uniformly, it is necessary to take measures such as lengthening or strengthening the kneading. Therefore, in the production of a molded product, there is a concern about a technical bottleneck that sufficient performance cannot be obtained despite an increase in cost and an improvement in fracture toughness value, which is not necessarily a satisfactory technique.

On the other hand, in order to impart rigidity to the vinyl chloride polymer, a method of adding an inorganic filler such as calcium carbonate, talc or mica to the vinyl chloride polymer is generally used. In this case, the more finely the inorganic filler is dispersed,
The elastic modulus is improved. For example, the layered swelling silicate is an inorganic mineral composed of very fine flaky crystals having a thickness of about 1 nm that are aggregated in layers by ionic bonds. The layered structure is formed by chemical or physical means. By exfoliating and dispersing flaky crystals in the polymer material in the size of nano-order level (so-called nanocomposite), not only elastic modulus but also heat resistance, gas barrier compared to the addition of conventional inorganic fillers. It has been known in recent years that the sex is remarkably improved.

In Japanese Patent Laid-Open No. 2000-159962,
A technique for improving elastic modulus and heat resistance by finely dispersing a layered swelling silicate organically modified with a specific amino compound in a vinyl chloride polymer at a nano level is disclosed. However, in these disclosed techniques, although the rigidity is improved, the ductility is remarkably reduced, and it is still insufficient for use as an industrial material.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it can be used for a long period of time without deteriorating the tensile elongation property while maintaining the high elastic modulus peculiar to a vinyl chloride polymer. Vinyl chloride-based polymer composition having excellent toughness in a fracture mode such as crack propagation at time,
An object of the present invention is to provide a molded product obtained from the production method and the composition.

[0008]

The present invention for solving the above-mentioned problems is specified by the following.

(1) In a vinyl chloride polymer composition obtained by dispersing a layered swelling silicate in a vinyl chloride polymer, (A) the vinyl chloride polymer has an average degree of polymerization of 600 or more, As (B) the layered swelling silicate, one in which a part of the exchangeable inorganic cations existing between layers is replaced with an organic cation is used, and (C) the layered swelling silicic acid dispersed in the composition. The salt has an average layer thickness of 0.5 to 50 nm measured by an electron microscope, an average aspect ratio (ratio of layer length and layer thickness) of 10 or more, and (D) the layered swelling silicate, A vinyl chloride polymer composition, characterized in that 0.05 to 0.7% by weight of the composition is contained as a residue when the composition is completely burned at 950 ° C.

(2) The vinyl chloride polymer composition according to the above (1), wherein the organic cation is an ammonium ion.

(3) The ammonium ion has a hydrocarbon group having at least one polar group having 1 to 18 carbon atoms, and is a quaternary ammonium having 4 to 25 carbon atoms in total. Vinyl chloride polymer composition.

(4) The vinyl chloride polymer composition according to any one of the above (1) to (3), which has a fracture toughness value of 3.1 MPa · m ^1/2 or more measured according to ASTM D5045-99. object.

(5) When conducting polymerization in an aqueous medium in the presence of a polymerization initiator, vinyl chloride alone or together with a vinyl monomer copolymerizable with vinyl chloride, either from before initiation of polymerization to completion of polymerization. The layered swelling silicate in which a part of the exchangeable inorganic cations existing between the layers is replaced with an organic cation is added at one time or at once. A method for producing the vinyl chloride polymer composition described.

(6) The method for producing a vinyl chloride polymer composition according to the above (5), wherein the organic cation is an ammonium ion.

(7) The above-mentioned (6), wherein the ammonium ion is a quaternary ammonium having at least one hydrocarbon group having a polar group of 1 to 18 carbon atoms and having a total of 4 to 25 carbon atoms. A method for producing a vinyl chloride polymer composition.

(8) A molded product obtained by molding the vinyl chloride polymer composition according to any one of (1) to (4) above.

(9) The molded product according to (8) above, wherein the molded product is a pipe.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a vinyl chloride polymer composition obtained by dispersing a very small amount of a layered swelling silicate having a specific particle shape, a method for producing the same, and a molded article thereof, which has fracture toughness. By optimizing the composition and dispersion morphology using an index called a value (measured according to ASTM D5045-99), both long-term durability and rigidity of the obtained molded product are achieved.

That is, the vinyl chloride polymer composition of the present invention uses a layered swelling silicate ion-exchanged with an exchangeable inorganic cation existing between the layers to form an organic cation. Of a hydrophilic silicate to a vinyl chloride polymer is improved, and a very small amount of a layered swelling silicate such as 0.05 to 0.7% by weight is contained in the vinyl chloride polymer as an average layer. 0.5 to 5 as thickness
It is characterized in that a finely dispersed structure having a size of 0 nm and an aspect ratio of 10 or more is formed. By forming such a structure, while maintaining a high elastic modulus, the fracture toughness value is significantly improved without impairing the elongation property,
It is possible to improve the long-term durability of the molded product, specifically, the toughness in a fracture mode such as crack growth property during long-term use.

Although the reason for this is not clear, the structure of the molded article obtained by the present invention has a layered swelling property in the form of flakes finely dispersed in a nano-order level size when observed with a transmission electron microscope. Silicate, without overlapping, so as to cover the interface of the residual particle structure of the vinyl chloride polymer, since it has a multilayer structure dispersed in a mesh, when the expansion stress occurs in the molded product, It is possible to achieve both high rigidity of the residual grain structure interface itself and local plastic deformation of the interface with the formation of many crazes and microvoids due to the dispersion of stress concentration points at the residual grain structure interface. It is expected to improve.

In this case, when the content of the layered swelling silicate in the composition is increased, the flaky crystals of the layered swelling silicate dispersed in the residual particle structure interface are excessively overlapped with each other, and the residual particles are Although the rigidity of the structural interface itself becomes high, the stress concentration applied there cannot be dispersed, and the fracture toughness value decreases. Further, if the content of the layered swelling silicate is too low, rigidity is insufficiently imparted to the residual grain structure interface itself, and the dispersion efficiency of stress concentration is also poor, and a molded product with a satisfactory fracture toughness value can be obtained. Absent. Therefore, in order to obtain molded articles with high fracture toughness values, there is an optimum content of layered swelling silicate in the composition.

If the layered swelling silicate is poorly dispersed, that is, if the flaky crystals are dispersed in a large structural unit in which flaky crystals are aggregated, each behaves as a structural defect and promotes crack propagation, resulting in fracture. The toughness value decreases. Therefore, in order to obtain a molded article with a high fracture toughness value, there is an optimum size when the layered swelling silicate is dispersed, and the layered swelling silicate is up to the above-mentioned nano-order level size. Need to be finely dispersed.

As described above, the vinyl chloride polymer composition of the present invention is characterized by having a structure in which a very small amount of layered swelling silicate is finely dispersed to a nano-order level size. The production method is not particularly limited, but the following two production methods are preferable.

As a first method, exchangeable inorganic cations such as sodium ions and calcium ions existing between layers of a layered swelling silicate are ion-exchanged with an organic cation to give a layered swelling silica which is originally hydrophilic. Examples thereof include a method of melt-kneading a predetermined amount of a layered swelling silicate and a vinyl chloride polymer, which are obtained by hydrophobizing or organizing an acid salt and modifying the structure to be compatible with the vinyl chloride polymer.

As a second method, when a vinyl chloride polymer is produced by a suspension polymerization method, the above-mentioned organically modified layered layer is formed before the start of polymerization and / or at the time from the start of polymerization to the end of polymerization. The swelling silicate is dispersed in an aqueous medium or in vinyl chloride monomer droplets to carry out suspension polymerization, and a predetermined amount of layered swelling silicic acid is added to the vinyl chloride monomer droplets during the polymerization process. Examples thereof include a method of adsorbing a salt and finely dispersing it in a vinyl chloride polymer.

Although the present invention is intended to improve the fracture toughness value by the means described above, the fracture toughness value is preferably 3.1.
MPa · m ^1/2 or more, more preferably 3.7 MPa ·
m ^1/2 or more, and most preferably 4.0 MPa · m ^1/2 or more. Here, the fracture toughness value is measured by ASTM D-50.
According to 45-95, it can be determined by a three-point bending test using a flat plate with a notch inserted on one side. By setting the fracture toughness value to the above value, a molded article having excellent long-term durability can be obtained. There is no particular upper limit to the fracture toughness value, but it is sufficient if it is, for example, about 6.0 MPa · m ^1/2 . As will be described later in Examples and the like, according to the present invention, a high fracture toughness value Kc is obtained without impairing the elastic modulus of a molded article, and a high-quality vinyl chloride polymer composition is provided.

The vinyl chloride-based polymer in the present invention is a homopolymer of vinyl chloride or a copolymer of vinyl chloride and another vinyl-based monomer copolymerizable with vinyl chloride, and further vinyl chloride, Examples thereof include a partially cross-linked vinyl chloride polymer obtained by copolymerization with other vinyl-based monomers and polyfunctional monomers which can be copolymerized, if necessary.

Other vinyl monomers copolymerizable with vinyl chloride used here include α-monoolefin monomers such as ethylene, propylene and butylene; vinyl esters such as vinyl acetate and vinyl propionate; Alkyl vinyl ethers such as methyl vinyl ether and cetyl vinyl ether; styrene derivatives such as styrene and α-methyl styrene; (meth) acrylic acid esters such as n-butyl acrylate, 2-ethylhexyl acrylate and methyl methacrylate; acrylonitrile, methacrylonitrile, etc. Vinyl cyanide; N-substituted maleimides such as cyclohexylmaleimide and phenylmaleimide; vinylidenes such as vinylidene chloride; and at least one of them is copolymerized with vinyl chloride.

As the vinyl chloride to be partially crosslinked and the polyfunctional monomer, polyfunctional allyl compounds such as diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl fumarate, diallyl adipate and triallyl cyanurate; ethylene glycol divinyl ether. , Polyfunctional vinyl ethers such as octadecane divinyl ether; 1,3-butylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth)
Examples thereof include polyfunctional (meth) acrylates such as acrylate, polyethylene glycol di (meth) acrylate, and trimethylolpropane tri (meth) acrylate. At least one of these is copolymerized with vinyl chloride to obtain a vinyl chloride polymer partially having a crosslinked structure.

The vinyl chloride polymer has an average degree of polymerization of 60.
It is 0 or more. When the content is within this range, the fracture toughness value of the obtained molded product can be improved. If the average degree of polymerization of the vinyl chloride polymer is less than 600, the effect of improving the fracture toughness value cannot be obtained. The vinyl chloride polymer has an average degree of polymerization of 600 to 3000, preferably 700 to 200.
When it is 0, the balance between the fracture toughness value and the moldability is further improved, the fluidity at the time of molding is good, the kneading torque of the molding machine is small, and a molded product having a high fracture toughness value is obtained, which is preferable.

The vinyl chloride-based polymer may be produced by any method such as suspension polymerization method, emulsion polymerization method, solution polymerization method, bulk polymerization method and the like, and is not particularly limited, but suspension polymerization method is used. The produced product has less residual monomer and is preferable.

The suspension polymerization method of a vinyl chloride polymer is well known, and a known method may be used without any particular limitation.

The layered swelling silicate in the present invention is
It has a structure in which flaky crystals consisting mainly of silicon oxide tetrahedron sheets and mainly metal hydroxide octahedron sheets are laminated in layers, and water-soluble with exchangeable cations such as sodium and calcium ions between layers. Is a silicate mineral. The type of the layered swelling silicate is not particularly limited, for example, montmorillonite, saponite, hectorite, beidellite, nontrilonite,
Examples thereof include smectite clay minerals such as sauconite and bentonite, vermiculite, halloysite, and swelling mica. These may be natural or synthetic. Among them, montmorillonite, bentonite, and swelling mica are preferable from the viewpoint of easy availability and improvement of physical properties.

In the present invention, an exchangeable inorganic cation such as sodium ion or calcium ion existing between layers of the layered swelling silicate is partially ion-exchanged with an organic cation. In the present invention, it is preferable that the organic cations are ion-exchanged so as to be 0.5 to 60% by weight, though the layered swelling silicate has a suitable hydrophobicity, although it varies depending on the type of the organic cations used. It has a good affinity when mixed with a vinyl chloride polymer, and the fracture toughness value is improved.

As the organic cations used here, protons (H ⁺ ) and other cations are added to the elements having these lone electron pairs of organic compounds containing oxygen, sulfur, nitrogen, phosphorus, arsenic, iodine and the like. And especially,
The monovalent cation is known as ONIUM.

Examples of onium include ammonium (nitrogen), phosphonium (phosphorus), arsonium (arsenic),
Stibonium (antimony), oxonium (oxygen),
Examples thereof include sulfonium (sulfur), selenonium (selenium), stannonium (tin), and iodonium (iodine). In addition, these may be used in combination as appropriate.

As the organic cation, an ammonium ion having a hydrocarbon group is preferable because it is easily available. Examples of the ammonium ion having a hydrocarbon group include trilaurylmethylammonium ion, didecyldimethylammonium ion, dicocoyldimethylammonium ion, distearyldimethylammonium ion, dioleyldimethylammonium ion, cetyltrimethylammonium ion, stearyltrimethylammonium ion. Ion, behenyltrimethylammonium ion, cocoylbis (2-hydroxyethyl) methylammonium ion, polyoxyethylene (15) cocostearylmethylammonium ion, oleylbis (2-hydroxyethyl) methylammonium ion,
Examples thereof include cocobenzyldimethylammonium ion, and these may be used alone or in combination of two or more kinds.

More preferably, the ammonium ion having a hydrocarbon group is a quaternary ammonium ion having a hydrocarbon group having 1 to 18 carbon atoms and a polar group and having 4 to 25 carbon atoms in total, vinyl chloride. The dispersibility of the layered swelling silicate in the polymer is improved, and the fracture toughness value is improved, which is preferable.

Examples of the above quaternary ammonium ion having a hydrocarbon group having 1 to 18 carbon atoms and a polar group and having 4 to 25 carbon atoms include polar groups such as hydroxyl group, mercapto group and carbonyl group. Etc. having one or more polar groups such as oleylbis (2-hydroxyethyl) methylammonium ion, laurylbis (2-hydroxyethyl) methylammonium ion, decylbis (2-hydroxyethyl) methylammonium ion, oleylbis (2- Examples thereof include mercaptoethyl) methylammonium ion, laurylbis (2-mercaptoethyl) methylammonium ion, and trimethylaminoethoxypropylammonium ion, which may be used alone or in combination of two or more.

As described above, in the present invention, the exchangeable inorganic cation existing between the layers of the layered swelling silicate is ion-exchanged with the organic cation, but the organic cation is used for the ion exchange. A layered swelling silicate in which the cation exchange capacity of the preceding layered swelling silicate is in the range of 50 to 200 meq / 100 g is preferable, and in the layered swelling silicate ion-exchanged with an organic cation. Content of the organic cation of 0.5 to 60% by weight, preferably,
It is preferably 1.0 to 50% by weight. When the content of (organic cation) is within the above range, not only a sufficient effect of improving the fracture toughness value can be obtained, but also discoloration of the molded product due to thermal decomposition of the organic cation at the time of molding can be suppressed, which is preferable.

The layered swelling silicate ion-exchanged with the organic cation used in the present invention is a known one in which the exchangeable inorganic cation existing between the layers of the layered swelling silicate is ion-exchanged with the organic cation. It is produced by a method, and there is no particular limitation on the production. For example, a layered swelling silicate is previously dissolved in an aqueous medium, and the layers are sufficiently swelled in the aqueous medium,
In an exfoliated state, an aqueous solution containing organic cations at room temperature,
A method of stirring and mixing, intercalating an organic cation between layers, and performing ion exchange is preferable because of high ion exchange efficiency.

In the present invention, the layers of the layered swelling silicate must be separated from each other in the molded product, and the flaky crystal units must be dispersed as much as possible. Therefore, the shape of the layered swelling silicate used in the present invention in a state of being dispersed in a molded article has an average layer thickness of 0.5 to 50 n.
m, and the average aspect ratio (ratio of layer length and layer thickness) is 1
It is 0 or more. Preferably, the average thickness is 0.5 to 30n
m, and the average aspect ratio is 20 to 500. More preferably, the average thickness is 0.5 to 20 nm and the average aspect ratio is 30 to 300.

When the average layer thickness of the layered swellable silicate dispersed in the molded article exceeds 50 nm or the average aspect ratio is less than 10, the layered swellable silicate is formed into the interlayer layer. Since the exfoliation is insufficient and a large number of flaky crystals are aggregated, it becomes a structural defect and a high fracture toughness value cannot be obtained, which is not preferable. The average thickness of the layered swelling silicate dispersed in the molded product is 0.5 n.
It is physically difficult to be less than m, and dispersibility to that extent is not required.

The content of the layered swelling silicate in the vinyl chloride polymer composition of the present invention is 0.05 to 0.7% by weight as the weight fraction of the inorganic component, preferably 0.
07-0.6% by weight, more preferably 0.1-0.6
% By weight.

If the content of the layered swelling silicate is less than 0.05% by weight as the weight fraction of the inorganic component, the effect of improving the fracture toughness value is poor, which is not preferable. Further, the content of the layered swelling silicate, as a weight fraction of the inorganic component,
When it exceeds 0.7% by weight, although the elastic modulus is improved, the fracture toughness value is remarkably lowered, which is not preferable.

By the way, the content of the layered swelling silicate was 95% in the molded article of the obtained vinyl chloride polymer composition.
It is completely combusted at 0 ° C., and is specified by measuring the weight of ash, and is defined as the weight fraction of inorganic components.

The production method of the present invention is not particularly limited. For example, a predetermined amount of a vinyl chloride polymer and a layered swelling silicate ion-exchanged with an organic cation are blended, and if necessary. Henschel mixer, raider machine, planetary mixer, blended with various additives
In addition, it can be obtained by uniform mixing using various mixers, etc., and may be so-called cold blending at room temperature or so-called hot blending in the range of 60 to 140 ° C. The vinyl chloride polymer composition produced by the above method, for example, by a kneader such as a single-screw extruder, a twin-screw extruder, a roll kneader, a Banbury mixer, melt kneading in a predetermined shear stress field, molding By producing a molded product by doing so, it is possible to form a structure in which a very small amount of the layered swelling silicate is finely dispersed in a size of nano-order level in the molded product.

However, when the layered swelling silicate ion-exchanged with the organic cation as described above is uniformly mixed with the vinyl chloride polymer, and the mixture is subjected to molding by melt kneading, a molded article is obtained. In order to exfoliate the layered swelling silicate to the flaky crystal unit and finely disperse it uniformly to the size of nano-order level, high shearing force is required during melt kneading, and kneading such as shear rate, temperature, kneading time, etc. It is necessary to optimize the conditions, and it cannot be said that the manufacturing method is optimal.

As a result of an examination in view of the above circumstances, as a more preferable method for producing the vinyl chloride polymer composition of the present invention, a vinyl chloride polymer and a layered swelling silicate ion-exchanged with an organic cation are simply used. When a vinyl chloride polymer is produced by a suspension polymerization method instead of mechanical blending, a layered swelling silicate ion-exchanged with an organic cation in the vinyl chloride polymer in the polymerization system. A method of finely dispersing the layered swelling silicate to a nano-order level size by the addition was found. That is, in the process of producing a vinyl chloride polymer by the suspension polymerization method, the layered swelling silicate ion-exchanged with an organic cation is dispersed in an aqueous medium or a vinyl chloride monomer droplet. Suspension polymerization to transfer the layered swelling silicate into the vinyl chloride monomer droplets and cause it to adsorb, and finely disperse the layered swelling silicate in the vinyl chloride polymer during the polymerization process. By using, further uniform dispersibility is improved, it is possible to significantly increase the fracture toughness value of the resulting molded article,
More preferable.

At that time, there is no particular limitation on the time of adding the layered swelling silicate ion-exchanged with the organic cation into the polymerization system, and for example, it may be added all at once before the initiation of the polymerization. It may be added all at once at a predetermined time during the polymerization, immediately before the end of the polymerization, or continuously and gradually during the predetermined period from the start to the end of the polymerization.

Other polymerization conditions, for example, the type and weight of the polymerization initiator used, the type and weight of the dispersant,
The stirring conditions and the like are not particularly limited, and a polymerization initiator which is commonly used in a known suspension polymerization method of a vinyl chloride-based polymer may be used and polymerization may be performed under normal stirring conditions.

The vinyl chloride polymer composition of the present invention is obtained by uniformly mixing the vinyl chloride polymer and the layered swelling silicate composite polymer obtained by the above-mentioned polymerization method together with various additives. Can be obtained by blending a predetermined amount of the vinyl chloride polymer and the composite polymer, and evenly mixing with various additives using various mixers, etc., at a predetermined temperature A molded product can be manufactured by melt-kneading in a shear stress field.

The vinyl chloride polymer composition of the present invention comprises
Additives such as pigments, dyes, heat stabilizers, antioxidants, UV absorbers, light stabilizers, lubricants, plasticizers, flame retardants, processing aids, impact modifiers, antistatic agents, etc., depending on the purpose. You may add.

Molded articles made of the composition of the present invention are
It can be obtained by melt-kneading and shaping by a known resin molding method such as press molding, extrusion molding, injection molding, blow molding, calender molding and the like. The temperature at the time of melt kneading is not particularly limited, but 140 to
Molding in a temperature range of 200 ° C. is preferable because a molded product having a high elastic modulus and a high fracture toughness value can be obtained. In particular, when a pipe is formed by extrusion molding, a pipe having high rigidity, high fracture toughness value, and long-term durability is obtained, which is preferable.

[0055]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. The vinyl chloride polymer compositions obtained in the following Examples and Comparative Examples were evaluated by the methods described below.

(Measurement method of average degree of polymerization) JIS-K67
According to No. 21, it was calculated by measuring the viscosity of a vinyl chloride polymer solution using nitrobenzene as a solvent. When the vinyl chloride polymer was not completely dissolved, the insoluble matter was filtered and the viscosity of the soluble matter was measured.

(Method for producing molded article) The vinyl chloride polymer composition was kneaded for 5 minutes with a roll having a temperature of 165 ° C. to produce a roll kneading sheet.
Press molding was carried out at 5 ° C. for 20 minutes under a pressure of 15 MPa to prepare a molded product.

(Measurement Method of Average Layer Thickness and Average Aspect Ratio of Layered Swelling Silicate in Molded Article) The molded article prepared above is cut into a thin piece having a thickness of 1 μm with an ultramicrotome, and the thin piece is a transmission type. Electron microscope (JEM, JEM
-2000FX) magnified 500,000 times and observed.
The layer thickness and the layer length of the layered swelling silicate dispersed in the mm square were measured, and the average layer thickness and the average aspect ratio were calculated.

(Measurement Method for Content of Layered Swelling Silicate in Molded Article) 1 g of the molded article prepared above was cut,
The content of the layered swelling silicate was calculated from the weight of ash by burning at 950 ° C. for 1 hour.

(Fracture toughness test method) Using the molded product prepared above, a flat plate having a notch inserted on one side was used with a tester (A & D Co., Ltd., Tensilon) according to ASTM D-5045-95. The fracture toughness value (Kc) was calculated from the maximum stress by a three-point bending test. For molded products that show non-linear fracture, when the maximum stress is reached,
The fracture toughness value (Kc) was calculated from the maximum stress, considering the crack growth starting point of the molded product.

(Measurement Method of Tensile Elastic Modulus and Elongation) Using the molded article prepared above, the tensile elastic modulus and elongation were measured with a testing machine (manufactured by A & D Co., Tensilon) according to JIS-K7113. .

Reference Example 1 (Production of montmorillonite A) 3 parts by weight of montmorillonite (Kunipia F manufactured by Kunimine Industries Co., Ltd.) purified from natural bentonite ore (referred to as montmorillonite C) was dissolved in 100 parts by weight of water. Then, 1.5 parts by weight of oleylbis (2-hydroxyethyl) methylammonium chloride was added with stirring, and the mixture was stirred for 60 minutes, and the precipitate that had aggregated and settled was dried to remove sodium ions between the layers of montmorillonite from oleylbis (2
A montmorillonite A containing 30% by weight as an organic component, which was ion-exchanged with -hydroxyethyl) methylammonium ion, was prepared.

Reference Example 2 (Production of Montmorillonite B) In the same manner as in Reference Example 1, except that distearyldimethylammonium chloride was used instead of oleylbis (2-hydroxyethyl) methylammonium chloride in Reference Example 1, an interlayer of montmorillonite was used. Was obtained by ion-exchange of sodium ion of the above with distearyldimethylammonium ion to obtain montmorillonite B containing 42 wt% as an organic component.

Reference Example 3 (Production of Polyvinyl Chloride-Layered Swelling Silicate Composite Polymer A) 2430 g of deionized water and 10.41 g of montmorillonite A were placed in a polymerization vessel having an inner volume of 3000 cm ³ equipped with a stirring blade.
Then, 0.73 g of partially saponified polyvinyl alcohol having an average saponification degree of 80% was charged, mixed with stirring, dissolved in water, and then 243 g of a vinyl chloride monomer and 0.13 g of a peroxide-based polymerization initiator were added to obtain 57.4%. Suspension polymerization was carried out at 0 ° C., and the obtained polyvinyl chloride-layered swellable silicate composite polymer A was separated by a conventional method. The average degree of polymerization of the obtained composite polymer A was 950, and the content of the layered swelling silicate in the polymer, which was determined from the ash content, was 3.20% by weight.

Example 1 Vinyl chloride polymer (TH-1000 manufactured by Taiyo PVC Co., Ltd.) 300 produced by a suspension polymerization method having an average degree of polymerization of 1020
g, montmorillonite A 0.34 obtained in Reference Example 1
g, dioctyl tin mercapto stabilizer (Sankyo Machine Co., Ltd.)
(Manufactured by: ONZ-82BF) 3 g, dipentaerythritol hexastearate (manufactured by Riken Vitamin Co., Ltd .: SL-0)
2) 3 g was mixed with a Henschel mixer, roll-kneaded and press-molded to prepare a vinyl chloride polymer composition. The content of montmorillonite quantified from the ash content of the obtained molded product was 0.08% by weight. The montmorillonite had an average layer thickness of 5 nm, an average aspect ratio of 105, and residual particles of vinyl chloride polymer. Along the interface,
It was dispersed like a mesh. Moreover, the fracture toughness value of the obtained molded product was high, and the tensile elastic modulus and tensile elongation were also high, which were good.

Example 2 A vinyl chloride polymer composition was prepared in the same manner as in Example 1 except that the amount of montmorillonite A was changed to 0.86 g. The content of montmorillonite quantified from the ash content of the obtained molded product was 0.2% by weight. The montmorillonite had an average layer thickness of 7 nm, an average aspect ratio of 110, and a residual vinyl chloride polymer. It was dispersed like a mesh along the grain interface. Moreover, the fracture toughness value of the obtained molded product was high, and the tensile elastic modulus and tensile elongation were also high, which were good.

Example 3 A vinyl chloride polymer composition was prepared in the same manner as in Example 1 except that the amount of montmorillonite A used was changed to 2.14 g. The content of montmorillonite quantified from the ash content of the obtained molded product was 0.5% by weight. The montmorillonite had an average layer thickness of 7 nm and an average aspect ratio of 95, and the residual vinyl chloride polymer. It was dispersed like a mesh along the grain interface. Moreover, the fracture toughness value of the obtained molded product was high, and the tensile elastic modulus and tensile elongation were also high, which were good.

Example 4 A vinyl chloride polymer composition was prepared in the same manner as in Example 1 except that the amount of montmorillonite A was changed to 3.0 g. The content of montmorillonite determined from the ash content of the obtained molded product was 0.7% by weight,
The montmorillonite had an average layer thickness of 10 nm and an average aspect ratio of 98, and was dispersed in a mesh shape along the interface of the residual particles of the vinyl chloride polymer. Moreover, the fracture toughness value of the obtained molded product was high, and the tensile elastic modulus and tensile elongation were also high, which were good.

Example 5 In Example 3, except that 300 g of a vinyl chloride polymer (TH-1300 manufactured by Taiyo PVC Co., Ltd.) produced by a suspension polymerization method having an average degree of polymerization of 1290 was used as the vinyl chloride polymer. In the same manner as in Example 3, a vinyl chloride polymer composition was prepared. The content of montmorillonite quantified from the ash content of the obtained molded product was 0.5% by weight. The montmorillonite had an average layer thickness of 5 nm, an average aspect ratio of 100, and a residual vinyl chloride polymer. It was dispersed like a mesh along the grain interface. Moreover, the fracture toughness value of the obtained molded product was high, and the tensile elastic modulus and tensile elongation were also high, which were good.

Example 6 A vinyl chloride polymer composition was prepared in the same manner as in Example 3 except that 2.59 g of montmorillonite B was used as the layered swelling silicate. The content of montmorillonite quantified from the ash content of the obtained molded product was 0.5% by weight. The montmorillonite had an average layer thickness of 15 nm, an average aspect ratio of 60, and remained vinyl chloride polymer. It was dispersed like a mesh along the grain interface. Moreover, the fracture toughness value of the obtained molded product was high, and the tensile elastic modulus and tensile elongation were also high, which were good.

Example 7 As a vinyl chloride polymer, a vinyl chloride polymer produced by a suspension polymerization method having an average degree of polymerization of 1020 (Tayo PVC Co., Ltd.)
Manufactured: TH-1000) 235.9 g, as a layered swelling silicate, polyvinyl chloride-layered swellable silicate composite polymer A64.1 g produced in Reference Example 3, as a stabilizer,
Dioctyl tin mercapto stabilizer (manufactured by Sankyo Machine Co., Ltd .:
3 g of ONZ-82BF) and 3 g of dipentaerythritol hexastearate (manufactured by Riken Vitamin Co., Ltd .: SL-02) as a lubricant are mixed with a Henschel mixer, roll-kneaded and press-molded to form a vinyl chloride polymer composition. The thing was made. The content of montmorillonite determined from the ash content of the obtained molded product was 0.5% by weight,
The montmorillonite had an average layer thickness of 5 nm and an average aspect ratio of 108, and was dispersed like a mesh along the interface of the residual particles of the vinyl chloride polymer. Moreover, the fracture toughness value of the obtained molded product was high, and the tensile elastic modulus and tensile elongation were also high, which were good. The above results are shown in Table 1.

[0072]

[Table 1]

Comparative Example 1 A vinyl chloride polymer composition was prepared in the same manner as in Example 1 except that montmorillonite A was not used in Example 1. The content of montmorillonite determined from the ash content of the obtained molded product was 0% by weight. The tensile elongation of the obtained molded product was high, but the fracture toughness value was low and the tensile elastic modulus was low, which was not preferable.

Comparative Example 2 In Example 1, as the layered swelling silicate, montmorillonite C refined from natural bentonite ore.
A vinyl chloride polymer composition was produced in the same manner as in Example 1 except that 1.5 g was used. The content of montmorillonite determined from the ash content of the obtained molded product was 0.5% by weight, and the average layer thickness of montmorillonite was 150 μm.
m, the average aspect ratio was 2.5, and the particles were dispersed in an aggregated state. The tensile elongation of the obtained molded product was high, but the fracture toughness value was low and the tensile elastic modulus was low, which was not preferable.

Comparative Example 3 A vinyl chloride polymer composition was prepared in the same manner as in Example 1 except that the amount of montmorillonite A was changed to 4.29 g. The content of montmorillonite quantified from the ash content of the obtained molded product was 1.0% by weight. The montmorillonite had an average layer thickness of 10 nm, an average aspect ratio of 65, and a residual vinyl chloride polymer. It was dispersed like a mesh along the grain interface. Further, although the obtained molded product had a high tensile modulus, it had a low fracture toughness value and a low tensile elongation, which was not preferable.

Comparative Example 4 A vinyl chloride polymer composition was prepared in the same manner as in Comparative Example 3 except that 8.57 g of montmorillonite A was added as the layered swelling silicate in Comparative Example 3. . The content of montmorillonite quantified from the ash content of the obtained molded product was 2.0% by weight. The montmorillonite had an average layer thickness of 11 nm and an average aspect ratio of 82, and the residual vinyl chloride polymer. It was dispersed like a mesh along the grain interface. Further, although the obtained molded product had a high tensile modulus, it had a low fracture toughness value and a low tensile elongation, which was not preferable.

Comparative Example 5 In Example 3, 300 g of a vinyl chloride polymer (TH-500 manufactured by Taiyo PVC Co., Ltd.) produced by a suspension polymerization method having an average degree of polymerization of 510 was used as the vinyl chloride polymer. A vinyl chloride polymer composition was produced in the same manner as in Example 3 except for the above. The content of montmorillonite determined from the ash content of the obtained molded product was 0.5% by weight, and the montmorillonite had an average layer thickness of 5 nm and an average aspect ratio of 98, and was uniformly dispersed. Further, the tensile modulus of the obtained molded product was high, but the fracture toughness value was low and the tensile modulus was low, which was not preferable. Table 2 shows the results of the above comparative examples.

[0078]

[Table 2]

[0079]

As described above, according to the present invention, a high elastic modulus is maintained and tensile elongation characteristics are not impaired.
It is possible to obtain a vinyl chloride polymer composition capable of obtaining a molded product having an excellent fracture toughness value.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 9/04 C08K 9/04 F16L 11/06 F16L 11/06 11/08 11/08 B (72) Invention Takashi Inoue 5-12-22-501 Kanaike, Yonezawa City, Yamagata Prefecture (72) Inventor Masahisa Enomoto 1-8 Kasumi, Yokkaichi, Mie Prefecture In-house (72) Inventor, Toshihiko Tanaka Kasumi, Yokkaichi, Mie 1- 8 Taiyo PVC Co., Ltd. In-house (72) Inventor Keizo Suzuki 1085 Nabekake, Kuroiso City, Tochigi Prefecture Kunimine Industry Co., Ltd. (72) Inventor Hiroyuki Enokido 23-5, Hakusaku, Joban Shimo-Funao, Iwaki, Fukushima Prefecture Kunimine Industry Co., Ltd. F term (reference) 3H111 AA02 BA15 BA31 BA34 CB02 CB14 DA11 DA12 EA04 4F071 AA24 AA81 AB30 AC05 AC06 AF13 AG01 BC05 4J002 BD031 DJ006 FA016 FB086 4J011 AA05 JB26 PA13 PB02 PB15 PB22 4J026 AC00 BA01 BA02 BA03 BA05 BA10 BA16 BA17 BA19 BA20 BA21 BA22 BA27 BA28 BA31 BA38 BA40 BA50 DB03

Claims (9)

[Claims] 1. A vinyl chloride polymer composition obtained by dispersing a layered swelling silicate in a vinyl chloride polymer,
(A) The vinyl chloride polymer has an average degree of polymerization of 600 or more, and (B) a layered swelling silicate in which a part of the exchangeable inorganic cations existing between layers is replaced with an organic cation. Is used, and the layered swelling silicate dispersed in the composition (C) has an average layer thickness of 0.5 measured by an electron microscope.
˜50 nm, an average aspect ratio (ratio of layer length to layer thickness) of 10 or more, and (D) the layered swelling silicate as a residue when the composition is completely burned at 950 ° C., A vinyl chloride polymer composition comprising 0.05 to 0.7% by weight of the composition. 2. The vinyl chloride polymer composition according to claim 1, wherein the organic cation is an ammonium ion. 3. The ammonium ion has a hydrocarbon group having at least one polar group having 1 to 18 carbon atoms,
The vinyl chloride polymer composition according to claim 2, which is a quaternary ammonium having a total carbon number of 4 to 25. 4. The vinyl chloride polymer composition according to claim 1, which has a fracture toughness value of 3.1 MPa · m ^1/2 or more as measured according to ASTM D5045-99. 5. Polymerization in an aqueous medium in the presence of a polymerization initiator with vinyl chloride alone or with a vinyl-based monomer copolymerizable with vinyl chloride, at any time from the initiation of the polymerization to the termination of the polymerization. 2. The layered swelling silicate in which a part of the exchangeable inorganic cations existing between the layers is replaced with an organic cation is added once or dividedly. A method for producing a vinyl chloride polymer composition. 6. The method for producing a vinyl chloride polymer composition according to claim 5, wherein the organic cation is an ammonium ion. 7. The ammonium ion has a hydrocarbon group having at least one polar group having 1 to 18 carbon atoms,
The method for producing a vinyl chloride polymer composition according to claim 6, which is a quaternary ammonium having a total carbon number of 4 to 25. 8. A molded article obtained by molding the vinyl chloride polymer composition according to any one of claims 1 to 4. 9. The molded product according to claim 8, wherein the molded product is a pipe.