Vinyl chloride resin pipe

Abstract

To provide a vinyl chloride-based resin pipe which reduces manufacture cost and can enhance impact resistance.SOLUTION: A vinyl chloride-based resin pipe is a vinyl chloride-based resin pipe obtained by molding a vinyl chloride-based resin composition containing a vinyl chloride-based resin, polyoxyalkylene glycol and calcium carbonate. In the vinyl chloride-based resin composition, with respect to 100 pts.wt. of the vinyl chloride-based resin, a content of the calcium carbonate is 10 pts.wt. or more and 35 pts.wt. or less and a content of the polyoxyalkylene glycol is 0.01 pts.wt. or more and 0.70 pts.wt. or less. The vinyl chloride-based resin pipe contains secondary particles of the calcium carbonate, and in the vinyl chloride-based resin pipe, an average particle diameter of the secondary particles of the calcium carbonate is 15 μm or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a vinyl chloride resin pipe using a vinyl chloride resin composition.

Background Art

[0002] Vinyl chloride resins are processed into various molded articles such as joints, pipes, plates, and containers, and are used in many fields. Since the above vinyl chloride resins are excellent in mechanical strength, weather resistance, heat resistance, and chemical resistance, they are particularly preferably used for pipes.

[0003] When producing a vinyl chloride resin composition and a vinyl chloride resin pipe (vinyl chloride resin molded article), additives such as a stabilizer and a lubricant may be used to improve the moldability. However, there is a problem that the stabilizer and the lubricant are relatively expensive and the production cost increases. Therefore, in order to reduce the production cost of the vinyl chloride resin composition and the vinyl chloride resin pipe (vinyl chloride resin molded article), inexpensive calcium carbonate may be used as a filler.

[0004] The following Patent Document 1 discloses a vinyl chloride resin composition containing a vinyl chloride resin and cubic calcium carbonate. Further, it is described that the above vinyl chloride resin composition preferably contains a plasticizer.

[0005] The following Patent Document 2 discloses a rigid polyvinyl chloride molded article containing 100 parts by mass of a polyvinyl chloride resin having an average degree of polymerization of 500 to 1500 and 10 to 40 parts by mass of calcium carbonate. Regarding the above calcium carbonate, the average primary particle diameter is 0.01 μm to 0.3 μm, and the coefficient of variation of the number of particles is 15% or less.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In Patent Documents 1 and 2, by adding calcium carbonate to a vinyl chloride resin composition, the production cost can be reduced to some extent.

[0008] However, since the compatibility between calcium carbonate and the vinyl chloride resin is poor, the calcium carbonate particles pulverized by mixing with the vinyl chloride resin are difficult to be uniformly dispersed in the vinyl chloride resin composition, and there is a problem that they aggregate into secondary particles during the composition or during molding. When there are secondary particles of calcium carbonate in a vinyl chloride resin pipe (vinyl chloride resin molded body), when an impact such as dropping is applied to the vinyl chloride resin pipe, cracks may occur starting from the secondary particles of calcium carbonate. That is, there is a problem that the impact resistance of the vinyl chloride resin pipe is lowered. In addition, since the kneading ability of extrusion molding is higher than that of injection molding, in extrusion molding, calcium carbonate particles are easily pulverized. As a result, in extrusion molding, the pulverized particles of calcium carbonate easily aggregate to form secondary particles, so there is a problem that the impact resistance of the vinyl chloride resin pipe is more likely to decrease.

[0009] Furthermore, in the vinyl chloride resin composition described in Patent Document 1, the heat resistance and impact resistance of the vinyl chloride resin composition may be further reduced by the plasticizer.

[0010] Also, in Patent Document 2, since the particle size of calcium carbonate in the vinyl chloride resin composition is too small, calcium carbonate is more likely to aggregate, and secondary particles of calcium carbonate are more likely to be formed. As a result, there is a problem that the impact resistance of the vinyl chloride resin molded body is more likely to deteriorate.

[0011] An object of the present invention is to provide a vinyl chloride resin pipe that can reduce manufacturing costs and enhance impact resistance.

Means for Solving the Problems

[0012] According to a broad aspect of the present invention, there is provided a vinyl chloride resin pipe formed from a vinyl chloride resin composition containing a vinyl chloride resin, a polyoxyalkylene glycol, and calcium carbonate. In the vinyl chloride resin composition, the content of the calcium carbonate is 10 parts by weight or more and 35 parts by weight or less with respect to 100 parts by weight of the vinyl chloride resin, and the content of the polyoxyalkylene glycol is 0.01 parts by weight or more and 0.70 parts by weight or less. The vinyl chloride resin pipe contains secondary particles of the calcium carbonate, and in the vinyl chloride resin pipe, the average particle diameter of the secondary particles of the calcium carbonate is 15 μm or less.

[0013] In a specific aspect of the vinyl chloride resin pipe according to the present invention, the polyoxyalkylene glycol is polyoxypropylene glycol.

[0014] In a specific aspect of the vinyl chloride resin pipe according to the present invention, in the vinyl chloride resin composition, the content of the polyoxyalkylene glycol is 0.1 parts by weight or more and 2.0 parts by weight or less with respect to 100 parts by weight of the calcium carbonate.

[0015] In a specific aspect of the vinyl chloride resin pipe according to the present invention, the vinyl chloride resin composition contains an organotin-based stabilizer.

[0016] In a specific aspect of the vinyl chloride resin pipe according to the present invention, the vinyl chloride resin pipe is an extruded body of the vinyl chloride resin composition.

Effects of the Invention

[0017] The vinyl chloride resin pipe according to the present invention is a vinyl chloride resin pipe formed from a vinyl chloride resin composition containing a vinyl chloride resin, a polyoxyalkylene glycol, and calcium carbonate. In the vinyl chloride resin pipe according to the present invention, in the above vinyl chloride resin composition, the content of the above calcium carbonate is 10 parts by weight or more and 35 parts by weight or less with respect to 100 parts by weight of the above vinyl chloride resin, and the content of the above polyoxyalkylene glycol is 0.01 part by weight or more and 0.70 part by weight or less. The vinyl chloride resin pipe according to the present invention contains secondary particles of the above calcium carbonate. In the vinyl chloride resin pipe according to the present invention, the average particle diameter of the secondary particles of the above calcium carbonate is 15 μm or less. Since the above configuration is provided in the vinyl chloride resin pipe according to the present invention, the manufacturing cost can be reduced and the impact resistance can be enhanced.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, the present invention will be described in detail.

[0019] The vinyl chloride resin pipe according to the present invention is a vinyl chloride resin pipe formed from a vinyl chloride resin composition containing a vinyl chloride resin, a polyoxyalkylene glycol, and calcium carbonate. In the vinyl chloride resin pipe according to the present invention, in the above vinyl chloride resin composition, the content of the above calcium carbonate is 10 parts by weight or more and 35 parts by weight or less with respect to 100 parts by weight of the above vinyl chloride resin, and the content of the above polyoxyalkylene glycol is 0.01 part by weight or more and 0.70 part by weight or less.

[0020] The vinyl chloride resin pipe according to the present invention contains secondary particles of the above calcium carbonate. In the vinyl chloride resin pipe according to the present invention, the average particle diameter of the secondary particles of the above calcium carbonate is 15 μm or less.

[0021] Since the above configuration is provided in the vinyl chloride resin pipe according to the present invention, the manufacturing cost can be reduced and the impact resistance can be enhanced.

[0022] In addition, the vinyl chloride resin pipe according to the present invention is obtained by molding the above vinyl chloride resin composition, and thus contains a vinyl chloride resin, a polyoxyalkylene glycol, and calcium carbonate. In the vinyl chloride resin pipe according to the present invention, the content of the calcium carbonate is preferably 10 parts by weight or more and 35 parts by weight or less, and the content of the polyoxyalkylene glycol is preferably 0.01 parts by weight or more and 0.70 parts by weight or less with respect to 100 parts by weight of the above vinyl chloride resin.

[0023] The above vinyl chloride resin pipe is a molded body of the above vinyl chloride resin composition. The above vinyl chloride resin pipe is preferably an extruded molded body of the above vinyl chloride resin composition.

[0024] The above vinyl chloride resin composition is used to obtain a vinyl chloride resin pipe. The above vinyl chloride resin composition is preferably used suitably to obtain an extruded vinyl chloride resin pipe. The above vinyl chloride resin composition is preferably extruded. The above vinyl chloride resin composition is preferably an extrusion molding vinyl chloride resin composition.

[0025] (Vinyl chloride resin composition) The above vinyl chloride resin composition contains a vinyl chloride resin, a polyoxyalkylene glycol, and calcium carbonate.

[0026] In this specification, one non-aggregated calcium carbonate in the material of the above vinyl chloride resin composition is defined as a primary particle of calcium carbonate. The pulverized product obtained by pulverizing the primary particles of the above calcium carbonate is defined as a pulverized particle of calcium carbonate. An aggregate in which two or more primary particles or pulverized particles of the above calcium carbonate are aggregated is defined as a secondary particle of calcium carbonate.

[0027] Hereinafter, each component and the like contained in the above vinyl chloride resin composition will be described. In the following description of the vinyl chloride resin composition, the above vinyl chloride resin pipe may also be described together.

[0028] In addition, in this specification, "(meth)acryl" means one or both of "acryl" and "methacryl", and "(meth)acrylate" means one or both of "acrylate" and "methacrylate".

[0029] <Vinyl chloride resin> The above vinyl chloride resin has a chlorine atom. The above vinyl chloride resin may be a chlorinated vinyl chloride resin, may be an unchlorinated vinyl chloride resin, or may be a mixture of a chlorinated vinyl chloride resin and an unchlorinated vinyl chloride resin. From the viewpoint of enhancing flame retardancy and heat distortion resistance, the above vinyl chloride resin is preferably a chlorinated vinyl chloride resin. The above chlorinated vinyl chloride resin is a resin obtained by chlorinating a vinyl chloride resin. Only one kind of the above vinyl chloride resin may be used, or two or more kinds may be used in combination.

[0030] Examples of the above vinyl chloride resin include a homopolymer of a vinyl chloride monomer, a copolymer of a vinyl chloride monomer and a vinyl monomer copolymerizable with the vinyl chloride monomer, and the like.

[0031] Examples of the vinyl monomer copolymerizable with the above vinyl chloride monomer include vinyl esters such as vinyl acetate, vinyl propionate, and vinyl ether; cyano group-containing compounds such as acrylonitrile; halogen compounds such as vinylidene chloride and vinyl fluoride; olefins such as ethylene and propylene; carboxyl group-containing compounds such as itaconic acid, maleic acid, and fumaric acid; non-aromatic carboxylic acid anhydrides such as maleic anhydride; (meth)acrylate esters such as methyl (meth)acrylate and ethyl (meth)acrylate; and imide compounds such as maleimide. Only one kind of the vinyl monomer copolymerizable with the above vinyl chloride monomer may be used, or two or more kinds may be used in combination.

[0032] The polymerization method of the above vinyl chloride monomer or the polymerization method of the above vinyl chloride monomer and a vinyl monomer copolymerizable with the above vinyl chloride monomer is not particularly limited. Examples of the above polymerization method include suspension polymerization method, emulsion polymerization method, solution polymerization method, bulk polymerization method, and precipitation polymerization method. From the viewpoint of efficiently obtaining a vinyl chloride-based resin, the above polymerization method is preferably a suspension polymerization method, an emulsion polymerization method, a solution polymerization method, or a precipitation polymerization method.

[0033] The above chlorinated vinyl chloride-based resin is preferably obtained by polymerizing the above vinyl chloride monomer or the above vinyl chloride monomer and a vinyl monomer copolymerizable with the above vinyl chloride monomer to obtain a vinyl chloride-based resin, and then chlorinating the vinyl chloride-based resin.

[0034] The method for chlorinating the above vinyl chloride-based resin is not particularly limited. Examples of the method for chlorinating the above vinyl chloride-based resin include a method in which the vinyl chloride-based resin is put into an aqueous solvent to obtain a suspension, and then chlorine is added to react the vinyl chloride-based resin with chlorine. This chlorination reaction proceeds under heating conditions or light irradiation conditions.

[0035] From the viewpoint of enhancing the thermal stability of the obtained chlorinated vinyl chloride-based resin, the above chlorination reaction is preferably carried out under heating conditions.

[0036] From the viewpoint of enhancing the efficiency of the chlorination reaction, the temperature during the above heating is preferably 65 °C or higher and preferably 130 °C or lower.

[0037] The chlorine content of the above vinyl chloride-based resin (when the vinyl chloride-based resin is a chlorinated vinyl chloride-based resin, the chlorine content of the chlorinated vinyl chloride-based resin) can be determined by a potentiometric titration method in accordance with JIS K7229.

[0038] The degree of polymerization of the above vinyl chloride resin is preferably 500 or more, more preferably 800 or more, preferably 2000 or less, more preferably 1100 or less, and even more preferably 1000 or less. When the degree of polymerization is at least the above lower limit, the durability of the vinyl chloride resin pipe can be enhanced, and the impact resistance can be further enhanced. When the degree of polymerization is at most the above upper limit, the melt viscosity of the vinyl chloride resin and the vinyl chloride resin composition can be lowered, so that the fluidity during molding can be enhanced.

[0039] In 100% by weight of the above vinyl chloride resin composition and in 100% by weight of the above vinyl chloride resin pipe, the content of the vinyl chloride resin is preferably 65% by weight or more, more preferably 70% by weight or more, and even more preferably 75% by weight or more, preferably 95% by weight or less, more preferably 92% by weight or less, and even more preferably 91% by weight or less. When the content of the vinyl chloride resin is at least the above lower limit, the adhesion strength of the vinyl chloride resin pipe can be enhanced, and the impact resistance can be further enhanced. When the content of the vinyl chloride resin is at most the above upper limit, it is not necessary to set the temperature during molding to a high temperature, and the moldability can be improved.

[0040] The vinyl chloride resin contained in the above vinyl chloride resin composition is preferably in the form of particles. The particle size of the vinyl chloride resin in the form of particles is preferably 0.1 μm or more and preferably 500 μm or less. When the particle size is at least the above lower limit, the handleability can be enhanced. When the particle size is at most the above upper limit, the moldability can be improved.

[0041] The particle size of the above vinyl chloride resin is preferably the average particle size, and preferably the volume average particle size. The volume average particle size of the above vinyl chloride resin is the average diameter measured on a volume basis and is the value of the median diameter (D50) at which it becomes 50%. The above volume average particle size can be measured by a laser diffraction / scattering method or the like.

[0042] <Polyoxyalkylene glycol> By using the polyoxyalkylene glycol and calcium carbonate in combination, the primary particles and pulverized particles of the calcium carbonate can be uniformly dispersed in the vinyl chloride resin composition and the vinyl chloride resin pipe, and the formation of secondary particles of the calcium carbonate can be suppressed.

[0043] Examples of the polyoxyalkylene glycol include polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, and polyoxyethylene-polyoxypropylene copolymer. Only one kind of the polyoxyalkylene glycol may be used, or two or more kinds may be used.

[0044] From the viewpoint of improving the appearance of the vinyl chloride resin pipe and further enhancing the impact resistance by suppressing the formation of secondary particles of calcium carbonate, the polyoxyalkylene glycol is preferably polyoxyethylene glycol or polyoxypropylene glycol, and more preferably polyoxypropylene glycol.

[0045] From the viewpoint of improving the appearance of the vinyl chloride resin pipe and further enhancing the impact resistance by suppressing the formation of secondary particles of calcium carbonate, the number of carbon atoms of the alkylene group in the polyoxyalkylene glycol is preferably 2 or more and preferably 4 or less. The alkylene group in the polyoxyalkylene glycol may be only one kind or two or more kinds.

[0046] The alkylene group in the polyoxyalkylene glycol may or may not have a side chain. Examples of the side chain include a methyl group, an ethyl group, a propyl group, and a butyl group. The side chain of the alkylene group in the polyoxyalkylene glycol may be only one kind or two or more kinds.

[0047] From the viewpoint of more uniformly dispersing the primary particles and pulverized particles of the calcium carbonate in the vinyl chloride resin composition and the vinyl chloride resin pipe and further suppressing the formation of secondary particles of the calcium carbonate, the polyoxyalkylene glycol preferably has a carboxy group at its terminal, and more preferably has carboxy groups at both terminals.

[0048] The molecular weight of the polyoxyalkylene glycol is preferably 100 or more, more preferably 2000 or more, still more preferably 3000 or more, and preferably 10000 or less, more preferably 8000 or less, still more preferably 6000 or less. When the molecular weight of the polyoxyalkylene glycol is not less than the above lower limit and not more than the above upper limit, the formation of secondary particles of the calcium carbonate can be suppressed, so that the appearance of the vinyl chloride resin pipe can be improved and the impact resistance can be further enhanced. The molecular weight is preferably the number average molecular weight.

[0049] When the structural formula of the polyoxyalkylene glycol can be specified, the molecular weight of the polyoxyalkylene glycol means the molecular weight calculated from the structural formula. When the polyoxyalkylene glycol is a polymer or the like whose structural formula cannot be specified, it means the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0050] In the above vinyl chloride resin composition, the content of the polyoxyalkylene glycol is 0.01 part by weight or more and 0.70 part by weight or less with respect to 100 parts by weight of the vinyl chloride resin. Further, in the above vinyl chloride resin pipe, the content of the polyoxyalkylene glycol is preferably 0.01 part by weight or more and preferably 0.70 part by weight or less with respect to 100 parts by weight of the vinyl chloride resin. In each of the above vinyl chloride resin composition and the above vinyl chloride resin pipe, the content of the polyoxyalkylene glycol is preferably 0.05 part by weight or more, more preferably 0.10 part by weight or more, preferably 0.60 part by weight or less, and more preferably 0.56 part by weight or less with respect to 100 parts by weight of the vinyl chloride resin. When the content of the polyoxyalkylene glycol is at least the above lower limit, the primary particles and pulverized particles of the calcium carbonate can be more uniformly dispersed in the vinyl chloride resin composition and the vinyl chloride resin pipe, and the formation of secondary particles of the calcium carbonate can be suppressed. As a result, the appearance of the vinyl chloride resin pipe can be improved, and the impact resistance can be further enhanced. When the content of the polyoxyalkylene glycol is at most the above upper limit, the polyoxyalkylene glycol present between the pulverized particles of the calcium carbonate is difficult to be removed, and the aggregation of the pulverized particles of the calcium carbonate can be prevented, so that the formation of secondary particles of the calcium carbonate can be suppressed. As a result, the appearance of the vinyl chloride resin pipe can be improved, and the impact resistance can be further enhanced.

[0051] In each of the above vinyl chloride resin composition and the above vinyl chloride resin pipe, the content of the polyoxyalkylene glycol is preferably 0.1 part by weight or more, more preferably 0.5 part by weight or more, and still more preferably 0.8 part by weight or more, based on 100 parts by weight of the calcium carbonate. In each of the above vinyl chloride resin composition and the above vinyl chloride resin pipe, the content of the polyoxyalkylene glycol is preferably 2.0 parts by weight or less, more preferably 1.6 parts by weight or less, and still more preferably 1.4 parts by weight or less, based on 100 parts by weight of the calcium carbonate. When the content of the polyoxyalkylene glycol is at least the above lower limit, the primary particles and the pulverized particles of the calcium carbonate can be uniformly dispersed in the vinyl chloride resin composition and the vinyl chloride resin pipe, and the formation of secondary particles of the calcium carbonate can be suppressed. As a result, the appearance of the vinyl chloride resin pipe can be improved, and the impact resistance can be further enhanced. When the content of the polyoxyalkylene glycol is at most the above upper limit, the polyoxyalkylene glycol present between the pulverized particles of the calcium carbonate is difficult to be removed, and the aggregation of the calcium carbonate can be prevented, so that the formation of secondary particles of the calcium carbonate can be suppressed. As a result, the appearance of the vinyl chloride resin pipe can be improved, and the impact resistance can be further enhanced.

[0052] <Calcium carbonate> In the above vinyl chloride resin composition and the above vinyl chloride resin pipe, the calcium carbonate acts as a filler.

[0053] In the material of the above vinyl chloride resin composition, the above calcium carbonate exists as primary particles. The primary particles of the above calcium carbonate may be pulverized into two or more particles by mixing with a vinyl chloride resin or the like during the preparation of the vinyl chloride resin composition, and become pulverized particles. The pulverized particles of the above calcium carbonate are formed by pulverizing the primary particles of the above calcium carbonate. The primary particles and pulverized particles of the above calcium carbonate may aggregate in the above vinyl chloride resin composition and during molding to form secondary particles. The secondary particles of the above calcium carbonate are formed by two or more of the above primary particles or pulverized particles of the above calcium carbonate. The secondary particles of the above calcium carbonate may be formed only by the above primary particles of the above calcium carbonate, may be formed only by the above pulverized particles of the above calcium carbonate, or may be formed by a combination of the above primary particles and pulverized particles of the above calcium carbonate.

[0054] The above vinyl chloride resin composition may contain the primary particles of the above calcium carbonate, may contain the pulverized particles of the above calcium carbonate, or may contain the primary particles and pulverized particles of the above calcium carbonate. The above vinyl chloride resin composition preferably contains the pulverized particles of the above calcium carbonate. The above calcium carbonate in the above vinyl chloride resin composition is preferably the pulverized particles of the above calcium carbonate. In the above vinyl chloride resin composition, the above calcium carbonate particles preferably exist as pulverized particles. Incidentally, the above calcium carbonate is preferably not aggregated in the above vinyl chloride resin composition. The above vinyl chloride resin composition preferably does not contain the secondary particles of the above calcium carbonate.

[0055] From the viewpoint of more effectively exerting the effects of the present invention, the particle diameter (primary particle diameter) of the primary particles of the above calcium carbonate is preferably 0.5 μm or more, more preferably 0.8 μm or more, still more preferably 1.0 μm or more, and preferably 10 μm or less, more preferably 5.0 μm or less, still more preferably 3.0 μm or less.

[0056] From the viewpoint of more effectively exerting the effects of the present invention, the particle diameter (ground particle diameter) of the ground particles of the calcium carbonate is preferably 0.1 μm or more, more preferably 0.2 μm or more, still more preferably 0.5 μm or more, and preferably 5.0 μm or less, more preferably 3.0 μm or less, still more preferably 2.0 μm or less.

[0057] From the viewpoint of more effectively exerting the effects of the present invention, the particle diameter (secondary particle diameter) of the secondary particles of the calcium carbonate in the vinyl chloride resin composition is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1.5 μm or more, and preferably 15 μm or less, more preferably 14 μm or less, still more preferably 10 μm or less.

[0058] The primary particle diameter, ground particle diameter, and secondary particle diameter of the calcium carbonate are preferably average particle diameters, and preferably number average particle diameters. The particle diameter of the calcium carbonate can be determined, for example, by observing 50 arbitrary calcium carbonates with an electron microscope or an optical microscope and calculating the average value of the particle diameters of each calcium carbonate, or by using a particle size distribution measuring device. In the observation with an electron microscope or an optical microscope, the particle diameter of each calcium carbonate is determined as the particle diameter equivalent to a circle. In the observation with an electron microscope or an optical microscope, the average particle diameter in terms of the circle equivalent diameter of 50 arbitrary calcium carbonates is substantially equal to the average particle diameter in terms of the sphere equivalent diameter. In the particle size distribution measuring device, the particle diameter of each calcium carbonate is determined as the particle diameter in terms of the sphere equivalent diameter. The average particle diameter of the calcium carbonate is preferably calculated using a particle size distribution measuring device.

[0059] The primary particles, crushed particles, and secondary particles of the calcium carbonate may be spherical, may have a shape other than spherical, or may have a shape such as square prism, circular column, or flat shape. From the viewpoint of further enhancing impact resistance and increasing fluidity during molding, the shapes of the primary particles, crushed particles, and secondary particles of the calcium carbonate are preferably spherical. The aspect ratio of the primary particles, crushed particles, and secondary particles of the calcium carbonate is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.2 or less.

[0060] In the above vinyl chloride resin composition, based on 100 parts by weight of the vinyl chloride resin, the content of the calcium carbonate is 10 parts by weight or more and 35 parts by weight or less. Also, in the above vinyl chloride resin pipe, based on 100 parts by weight of the vinyl chloride resin, the content of the calcium carbonate is preferably 10 parts by weight or more and preferably 35 parts by weight or less. In the present invention, since the above configuration is provided, the manufacturing costs of the above vinyl chloride resin composition and the above vinyl chloride resin pipe can be reduced. Also, the fluidity during molding can be increased, and the appearance of the above vinyl chloride resin pipe can be improved. In each of the above vinyl chloride resin composition and the above vinyl chloride resin pipe, based on 100 parts by weight of the vinyl chloride resin, the content of the calcium carbonate is preferably 12 parts by weight or more, more preferably 15 parts by weight or more, preferably 30 parts by weight or less, and more preferably 25 parts by weight or less. When the content of the calcium carbonate is above the above lower limit and below the above upper limit, the manufacturing cost can be further reduced, and the impact resistance can be further enhanced.

[0061] The above vinyl chloride resin composition and the above vinyl chloride resin pipe may contain a filler other than the calcium carbonate. Examples of the filler other than the calcium carbonate include talc.

[0062] <Other components> In the above vinyl chloride resin composition and the above vinyl chloride resin pipe, various additives may be used as required. Examples of the above additives include stabilizers, heat stabilization auxiliaries, lubricants, processing aids, impact modifiers, heat resistance improvers, antioxidants, ultraviolet absorbers, antistatic agents, light stabilizers, pigments, flame retardants, and plasticizers. Only one kind of the above additives may be used, or two or more kinds may be used in combination.

[0063] The above vinyl chloride resin composition and the above vinyl chloride resin pipe preferably contain a stabilizer. Examples of the above stabilizers include organotin stabilizers, lead stabilizers, calcium-zinc stabilizers, barium-zinc stabilizers, and barium-cadmium stabilizers. Only one kind of the above stabilizers may be used, or two or more kinds may be used in combination.

[0064] The above stabilizer is preferably a heat stabilizer.

[0065] From the viewpoint of suppressing the decomposition of the vinyl chloride resin and capturing hydrogen chloride generated during the decomposition of the vinyl chloride resin, the above vinyl chloride resin composition and the above vinyl chloride resin pipe preferably contain an organotin stabilizer, and more preferably contain an organotin heat stabilizer. In addition, the use of an organotin stabilizer improves the appearance of the vinyl chloride resin pipe.

[0066] Examples of the above-mentioned organotin stabilizers include tin mercapto stabilizers, tin maleate stabilizers, and tin carboxylate stabilizers. Examples of the above-mentioned tin mercapto stabilizers include monoalkyltin mercapto, dialkyltin mercapto, monoalkyltin mercapto polymer, dialkyltin mercapto polymer, monoalkyltin mercapto sulfide, and dialkyltin mercapto sulfide. Examples of the above-mentioned dialkyltin mercapto include dimethyltin mercapto, dibutyltin mercapto, and dioctyltin mercapto. Examples of the above-mentioned tin maleate stabilizers include monoalkyltin maleate, dialkyltin maleate, monoalkyltin maleate polymer, and dialkyltin maleate polymer. Examples of the above-mentioned dialkyltin maleate include dibutyltin maleate and dioctyltin maleate. Examples of the above-mentioned dialkyltin maleate polymer include dibutyltin maleate polymer and dioctyltin maleate polymer. Examples of the above-mentioned tin carboxylate stabilizers include monoalkyltin carboxylate and dialkyltin carboxylate. Examples of the above-mentioned dialkyltin carboxylate include dibutyltin laurate. The above-mentioned organotin stabilizer may be used alone or in combination of two or more kinds.

[0067] From the viewpoint of improving the appearance of the above-mentioned vinyl chloride resin pipe, the above-mentioned organotin stabilizer is preferably a tin mercapto stabilizer, more preferably a dialkyltin mercapto, and even more preferably dioctyltin mercapto.

[0068] Examples of the above-mentioned lead stabilizers include tribasic lead sulfate, tetrabasic lead sulfate, basic lead sulfite, dibasic lead phosphite, dibasic lead phthalate, tribasic lead maleate, dibasic lead stearate, and basic lead sulfite phosphite.

[0069] In each of the above vinyl chloride resin composition and the above vinyl chloride resin pipe, the content of the above organotin stabilizer is preferably 0.2 parts by weight or more, more preferably 0.3 parts by weight or more, and still more preferably 0.4 parts by weight or more, based on 100 parts by weight of the above vinyl chloride resin. Also, in each of the above vinyl chloride resin composition and the above vinyl chloride resin pipe, the content of the above organotin stabilizer is preferably 3.0 parts by weight or less, more preferably 2.0 parts by weight or less, and still more preferably 1.8 parts by weight or less, based on 100 parts by weight of the above vinyl chloride resin. When the content of the above organotin stabilizer is equal to or higher than the above lower limit and equal to or lower than the above upper limit, the thermal stability can be enhanced and the heat resistance of the vinyl chloride resin pipe can be enhanced.

[0070] The above heat stabilizer aid is not particularly limited, and examples thereof include epoxidized soybean oil, phosphate ester, polyol, hydrotalcite, and zeolite. Only one kind of the above heat stabilizer aid may be used, or two or more kinds may be used in combination.

[0071] The above vinyl chloride resin composition and the above vinyl chloride resin pipe may or may not contain a lubricant. It is preferable that the above vinyl chloride resin composition and the above vinyl chloride resin pipe contain a lubricant.

[0072] Examples of the above lubricant include an internal lubricant and an external lubricant. The above internal lubricant is used for the purpose of reducing the flow viscosity of the molten resin during molding processing and preventing frictional heat generation. The above internal lubricant is not particularly limited, and examples thereof include butyl stearate, lauryl alcohol, stearyl alcohol, epoxidized soybean oil, glycerin monostearate, stearic acid, and bisamide. The above external lubricant is used for the purpose of enhancing the sliding effect between the molten resin and the metal surface during molding processing. The above external lubricant is not particularly limited, and examples thereof include polyethylene-based lubricants, ester-based lubricants, paraffin wax, polyolefin wax, and montanic acid wax. Only one kind of the above lubricant may be used, or two or more kinds may be used in combination.

[0073] From the viewpoint of improving the slipperiness between the vinyl chloride resin composition and the metal surface (mold) during molding, it is preferable that the vinyl chloride resin composition and the vinyl chloride resin pipe contain a polyethylene-based lubricant, and more preferably contain a polyethylene-based lubricant and an ester-based lubricant.

[0074] When the vinyl chloride resin composition and the vinyl chloride resin pipe contain the polyethylene-based lubricant, it is preferable to satisfy the following content. With respect to 100 parts by weight of the vinyl chloride resin, the content of the polyethylene-based lubricant is preferably more than 0 parts by weight, more preferably 0.1 parts by weight or more, still more preferably 0.5 parts by weight or more, preferably 10 parts by weight or less, more preferably 2 parts by weight or less, and still more preferably 1 part by weight or less. When the content of the polyethylene-based lubricant satisfies the above lower limit and upper limit, the primary particles and pulverized particles of the calcium carbonate can be uniformly dispersed in the vinyl chloride resin composition and the vinyl chloride resin pipe. As a result, the fluidity during molding can be increased, and the appearance of the vinyl chloride resin pipe can be improved. In addition, the slipperiness between the vinyl chloride resin composition and the metal surface (mold) during molding can be improved, and the appearance of the vinyl chloride resin pipe can be improved.

[0075] The vinyl chloride resin composition and the vinyl chloride resin pipe may contain the polyethylene-based lubricant and a lubricant other than the polyethylene-based lubricant.

[0076] When the above vinyl chloride resin composition and the above vinyl chloride resin pipe contain the above polyethylene-based lubricant and a lubricant other than the above polyethylene-based lubricant, it is preferable to satisfy the following contents. With respect to 100 parts by weight of the above vinyl chloride resin, the total content of the above polyethylene-based lubricant and the lubricant other than the above polyethylene-based lubricant (total content of lubricants) is preferably more than 0 parts by weight, more preferably 0.2 parts by weight or more, and still more preferably 0.4 parts by weight or more. With respect to 100 parts by weight of the above vinyl chloride resin, the total content of the above polyethylene-based lubricant and the lubricant other than the above polyethylene-based lubricant (total content of lubricants) is preferably 2.0 parts by weight or less, more preferably 1.5 parts by weight or less, and still more preferably 1.2 parts by weight or less. When the total content of the above polyethylene-based lubricant and the lubricant other than the above polyethylene-based lubricant satisfies the above lower limit and the above upper limit, the primary particles and pulverized particles of the above calcium carbonate can be uniformly dispersed in the above vinyl chloride resin composition and the above vinyl chloride resin pipe, and the formation of secondary particles of the above calcium carbonate can be suppressed. As a result, the fluidity during molding can be increased, and the appearance of the above vinyl chloride resin pipe can be improved. Further, the slipperiness between the vinyl chloride resin composition and the metal surface (mold) during molding can be improved, and the appearance of the above vinyl chloride resin pipe can be improved.

[0077] The above processing aid is not particularly limited. Examples of the above processing aid include acrylic processing aids. Examples of the above acrylic processing aid include alkyl acrylate-alkyl methacrylate copolymers having a weight average molecular weight of 100,000 to 2,000,000, and specifically, n-butyl acrylate-methyl methacrylate copolymer, 2-ethylhexyl acrylate-methyl methacrylate-butyl methacrylate copolymer, and the like. Only one kind of the above processing aid may be used, or two or more kinds may be used in combination.

[0078] The impact modifier is not particularly limited, and examples thereof include methyl methacrylate-butadiene-styrene copolymer (MBS), chlorinated polyethylene, and acrylic rubber. Only one kind of the impact modifier may be used, or two or more kinds may be used in combination.

[0079] The heat resistance improver is not particularly limited, and examples thereof include α-methylstyrene-based and N-phenylmaleimide-based resins. Only one kind of the heat resistance improver may be used, or two or more kinds may be used in combination.

[0080] The antioxidant is not particularly limited, and examples thereof include phenolic antioxidants. Only one kind of the antioxidant may be used, or two or more kinds may be used in combination.

[0081] The ultraviolet absorber is not particularly limited, and examples thereof include salicylic acid ester-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers. Only one kind of the ultraviolet absorber may be used, or two or more kinds may be used in combination.

[0082] The light stabilizer is not particularly limited, and examples thereof include hindered amine-based light stabilizers. Only one kind of the light stabilizer may be used, or two or more kinds may be used in combination.

[0083] The pigment is not particularly limited, and examples thereof include organic pigments and inorganic pigments. Examples of the organic pigments include azo-based organic pigments, phthalocyanine-based organic pigments, perylene-based organic pigments, and dye lake-based organic pigments. Examples of the inorganic pigments include oxide-based inorganic pigments, molybdate chromate-based inorganic pigments, sulfide / selenide-based inorganic pigments, and ferrocyanide-based inorganic pigments. From the viewpoint of further enhancing transparency, it is preferable that the vinyl chloride-based resin composition does not contain the pigment.

[0084] The above plasticizer may be added for the purpose of enhancing the processability during molding. Since the addition of the plasticizer may reduce the heat resistance of the molded product, it is preferable to use a small amount of the plasticizer. The above plasticizer is not particularly limited, and examples thereof include dibutyl phthalate, di-2-ethylhexyl phthalate, and di-2-ethylhexyl adipate. Only one type of the above plasticizer may be used, or two or more types may be used in combination.

[0085] (Other details of the vinyl chloride resin pipe) The above vinyl chloride resin pipe is formed using the above vinyl chloride resin composition. The above vinyl chloride resin composition can be used to obtain the above vinyl chloride resin pipe. The above vinyl chloride resin pipe is obtained by molding the above vinyl chloride resin composition. The above vinyl chloride resin pipe is a molded body of the above vinyl chloride resin composition. The above vinyl chloride resin pipe is preferably an extruded molded body of the above vinyl chloride resin composition.

[0086] In the above vinyl chloride resin pipe, the primary particles and pulverized particles of the above calcium carbonate can be uniformly dispersed. As a result, the appearance of the above vinyl chloride resin pipe can be improved.

[0087] Note that some of the primary particles and pulverized particles of the above calcium carbonate in the above vinyl chloride resin composition may aggregate in the composition or during molding. In the above vinyl chloride resin pipe, some of the primary particles and pulverized particles of the above calcium carbonate are aggregated. The above vinyl chloride resin pipe (the molded body of the above vinyl chloride resin composition) contains secondary particles of the above calcium carbonate. In the above vinyl chloride resin pipe, the primary particles, pulverized particles, and secondary particles of the above calcium carbonate may be present. The above vinyl chloride resin pipe may contain only the secondary particles of the above calcium carbonate, may contain primary particles and secondary particles, may contain pulverized particles and secondary particles, or may contain primary particles, pulverized particles, and secondary particles.

[0088] In the above vinyl chloride resin pipe, the particle diameter (secondary particle diameter) of the secondary particles of the calcium carbonate is 15 μm or less. The particle diameter of the secondary particles of the calcium carbonate in the vinyl chloride resin pipe is preferably 1.0 μm or more, more preferably 1.5 μm or more, still more preferably 2.0 μm or more, preferably 13 μm or less, more preferably 10 μm or less, still more preferably 8.0 μm or less, and particularly preferably 5.0 μm or less. When the particle diameter of the secondary particles of the calcium carbonate is equal to or greater than the above lower limit and equal to or less than the above upper limit, the appearance of the vinyl chloride resin pipe can be improved, and the impact resistance can be further enhanced.

[0089] The particle diameter of the secondary particles of the calcium carbonate is preferably the number average particle diameter. The particle diameter of the secondary particles of the calcium carbonate can be measured, for example, by the following method. Cut the vinyl chloride resin pipe using a diamond cutter and observe the cross-section with a scanning electron microscope. Use image analysis software to obtain the average value of the particle diameters of the secondary particles of calcium carbonate present in a unit area. Examples of the diamond cutter include "Marunoko Disk Model 2711" manufactured by Makita Corporation.

[0090] For example, when one secondary particle is composed of three primary particles of calcium carbonate, in this secondary particle, the number of primary particles of calcium carbonate that form the secondary particle is counted as 3. For example, when one secondary particle is composed of three pulverized particles of calcium carbonate, in this secondary particle, the number of pulverized particles of calcium carbonate that form the secondary particle is counted as 3.

[0091] The above vinyl chloride resin pipe may be a single-layer pipe or a multi-layer pipe.

[0092] The mixing method of the above vinyl chloride resin composition and the material of the above vinyl chloride resin pipe is not particularly limited. The above vinyl chloride resin composition and the material of the above vinyl chloride resin pipe may be mixed all at once, or a plurality of materials may be premixed. In the method for producing the above vinyl chloride resin composition and the above vinyl chloride resin pipe, it is preferable that the calcium carbonate (primary particles) and the polyoxyalkylene glycol are premixed. When the calcium carbonate and the polyoxyalkylene glycol are premixed, the polyoxyalkylene glycol is dispersed on the surface of the calcium carbonate, and aggregation of the primary particles and pulverized particles of the calcium carbonate can be prevented. As a result, it is possible to suppress the calcium carbonate from becoming secondary particles in the above vinyl chloride resin composition and during molding, so that the appearance of the above vinyl chloride resin pipe can be improved, and the impact resistance can be further enhanced. The calcium carbonate and the polyoxyalkylene glycol can be mixed, for example, using a mixer.

[0093] The molding machine used for molding is not particularly limited, and examples include a screw-type extrusion molding machine, a single-screw extruder, a twin-screw non-directional parallel extruder, a twin-screw non-directional conical extruder, and a twin-screw co-rotating extruder. In the above screw-type extrusion molding machine, the vinyl chloride resin composition filled in the cylinder is extruded from the tip of the screw after being molded by a mold and cooled by a water tank, thereby forming a vinyl chloride resin pipe (vinyl chloride resin molded body). When molding using the above molding machine, the mold for shaping, the resin temperature, etc. are not particularly limited.

[0094] Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited only to the following examples.

[0095] The following materials were prepared.

[0096] (Vinyl chloride resin) Vinyl chloride resin ("TS-1000R" manufactured by DAIYO KASEI CO., LTD., degree of polymerization: 1000)

[0097] (Polyoxyalkylene glycol) Polyoxypropylene glycol (manufactured by BYK, "DISPERPLAST 1180", molecular weight: 3.2×10 3 )

[0098] (Calcium carbonate) Calcium carbonate (manufactured by Maruo Calcium Co., Ltd., "Super #1700", average particle diameter of primary particles: 1.9 μm)

[0099] (Lubricant) Polyethylene-based lubricant (manufactured by Mitsui Chemicals, "HW2203A", acid value: 30) Ester-based lubricant (manufactured by Emery Oleo, "G15")

[0100] (Stabilizer) Organotin-based stabilizer (manufactured by Katsuta Chemical Industry Co., Ltd., "KM-19D-2")

[0101] (Example 1) 10 parts by weight of calcium carbonate and 0.15 parts by weight of polyoxypropylene glycol were added to a small crusher (manufactured by Sanjo Industry Co., Ltd., "Rotary Crusher NR-04A type") and mixed at 30000 rpm for 5 minutes to obtain a premixed composition. In the premixed composition, crushed particles of calcium carbonate were formed. The obtained premixed composition, 100 parts by weight of a vinyl chloride-based resin, 1.6 parts by weight of an organotin-based stabilizer, 0.5 parts by weight of a polyethylene-based lubricant, and 0.5 parts by weight of an ester-based lubricant were added to a rotary mixer (manufactured by Kawata Co., Ltd., "20L Super Mixer"). Then, steam was introduced and the mixture was rotationally mixed at 1500 rpm. After heating to 105°C, the steam was stopped, cooling water was passed through, and the mixture was rotationally mixed and cooled to 50°C to obtain a vinyl chloride-based resin composition.

[0102] Regarding the obtained vinyl chloride-based resin composition, a vinyl chloride-based resin tube (extruded molded body) was produced using a twin-screw unidirectional parallel extruder (manufactured by Nagata Seisakusho Co., Ltd., "SLM50") under the following conditions. The obtained vinyl chloride-based resin tube had a length of 40 cm, an outer diameter of 60 mm, and a thickness of 4.3 mm. In the vinyl chloride-based resin tube, secondary particles of calcium carbonate were formed.

[0103] [Extrusion Conditions] Mold: Pipe mold (caliber 50A) Total extrusion volume: 20 kg / h Resin temperature: 190 °C (temperature at the mold inlet)

[0104] (Examples 2 to 4, Comparative Examples 1 to 4, and Reference Example 1) Vinyl chloride resin compositions and vinyl chloride resin pipes were prepared in the same manner as in Example 1, except that the types and amounts of the compounding components were as shown in Tables 1 to 2 below.

[0105] (Evaluation) (1) Average particle diameter of secondary particles of calcium carbonate The obtained vinyl chloride resin pipe was cut into 3 mm lengths using a diamond cutter (Makita "Marunoko Slicer Model 2711"), and the cross-section was observed using a scanning electron microscope (JEOL "JSM-6510A"). Using image analysis software (ImageJ), the average value of the equivalent circle diameters of the secondary particles of calcium carbonate present in an arbitrary 1 cm 2 was determined and taken as the average particle diameter of the secondary particles.

[0106] (2) Impact resistance For the obtained vinyl chloride resin pipe, a falling weight impact test (impact resistance test) was carried out in accordance with Appendix JA of JIS K6743 using a falling weight tester (Nidec-Shimpo "TS-001") and a flat-bottomed weight with a mass of 3 kg. In accordance with JIS K7211, the 50% impact fracture height at 0 °C was calculated, and the ratio (%) of the 50% impact fracture height of Reference Example 1 containing no calcium carbonate was taken as the impact strength retention rate. The impact resistance of the vinyl chloride resin pipe was determined according to the following criteria. The following impact strength retention rate is preferably 50% or more.

[0107] [Judgment Criteria for Impact Resistance] ○○: Impact strength retention rate is 80% or more ○: Impact strength retention rate is 60% or more and less than 80% △: Impact strength retention rate is 50% or more and less than 60% ×: Impact strength retention rate is less than 50%

[0108] The compounding compositions and results are shown in Tables 1 to 2 below.

[0109]

Table 1

[0110]

Table 2

[0111] In the vinyl chloride resin pipes of Examples 1 to 4, the average particle diameter of the secondary particles of calcium carbonate was 15 μm or less. As a result, in the vinyl chloride resin pipes of Examples 1 to 4, a decrease in the impact strength retention rate can be prevented, and they are excellent in impact resistance. Further, in the vinyl chloride resin pipes of Examples 1 to 4, since calcium carbonate is contained in a specific content, the manufacturing cost can be reduced.

[0112] In Reference Example 1 which does not contain calcium carbonate, since secondary particles of calcium carbonate are not formed, it is excellent in impact resistance, but the manufacturing cost is high compared to Examples 1 to 4 which contain calcium carbonate.

Claims

1. A vinyl chloride resin pipe formed from a vinyl chloride resin composition containing a vinyl chloride resin, a polyoxyalkylene glycol, and calcium carbonate, wherein in the vinyl chloride resin composition, the content of the calcium carbonate is 10 parts by weight or more and 35 parts by weight or less with respect to 100 parts by weight of the vinyl chloride resin, and the content of the polyoxyalkylene glycol is 0.01 parts by weight or more and 0.70 parts by weight or less, the polyoxyalkylene glycol has carboxy groups at both ends, the vinyl chloride resin pipe contains secondary particles of the calcium carbonate, and in observation of a cross section of the vinyl chloride resin pipe by a scanning electron microscope, the average value of the equivalent circle diameter of the secondary particles of the calcium carbonate is 15 μm or less. A vinyl chloride resin pipe.

2. The vinyl chloride resin pipe according to claim 1, wherein the polyoxyalkylene glycol is polyoxypropylene glycol.

3. The vinyl chloride resin pipe according to claim 1 or 2, wherein in the vinyl chloride resin composition, the content of the polyoxyalkylene glycol is 0.1 parts by weight or more and 2.0 parts by weight or less with respect to 100 parts by weight of the calcium carbonate.

4. The vinyl chloride resin pipe according to any one of claims 1 to 3, wherein the vinyl chloride resin composition contains an organotin-based stabilizer.

5. The vinyl chloride resin pipe according to any one of claims 1 to 4, which is an extruded product of the vinyl chloride resin composition.

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