阅读说明：本技术 成形用树脂组合物 (Resin composition for molding ) 是由 谷口宽 后藤司 于 2018-09-26 设计创作，主要内容包括：本发明提供一种能够制造具有优异的热稳定性且耐冲击性和表面平滑性高的成形体的成形用树脂组合物、以及使用了成形用树脂组合物的成形体。本发明是一种成形用树脂组合物,其含有氯化氯乙烯系树脂、丙烯酸系加工助剂和耐冲击改良剂,其中,上述丙烯酸系加工助剂包含重均分子量为50万～500万的丙烯酸系树脂,相对于上述氯化氯乙烯系树脂100质量份,含有0.2～10质量份的上述丙烯酸系加工助剂、0.5～8.0质量份的上述耐冲击改良剂。(The invention provides a molding resin composition capable of producing a molded body with excellent thermal stability and high impact resistance and surface smoothness, and a molded body using the molding resin composition. The present invention is a molding resin composition comprising a chlorinated vinyl chloride resin, an acrylic processing aid and an impact resistance improver, wherein the acrylic processing aid comprises an acrylic resin having a weight average molecular weight of 50 to 500 ten thousand, and the acrylic processing aid is contained in an amount of 0.2 to 10 parts by mass and the impact resistance improver is contained in an amount of 0.5 to 8.0 parts by mass, based on 100 parts by mass of the chlorinated vinyl chloride resin.)

1. A molding resin composition comprising a chlorinated vinyl chloride resin, an acrylic processing aid and an impact modifier, wherein,

the acrylic processing aid comprises acrylic resin with the weight-average molecular weight of 50-500 ten thousand,

the acrylic processing aid is contained in an amount of 0.2 to 10 parts by mass and the impact modifier is contained in an amount of 0.5 to 8.0 parts by mass based on 100 parts by mass of the chlorinated vinyl chloride resin.

2. The resin composition for molding according to claim 1, wherein the chlorinated vinyl chloride-based resin has structural units (a) to (c) represented by the following formulae (a) to (c), and the proportion of the structural unit (a) is 17.5 mol% or less, the proportion of the structural unit (b) is 46.0 mol% or more, and the proportion of the structural unit (c) is 37.0 mol% or less, based on the total mole number of the structural units (a), (b), and (c),

-CCl₂- (a)

-CHCl- (b)

-CH₂- (c)。

3. the molding resin composition according to claim 1 or 2, wherein the chlorine content in the chlorinated vinyl chloride-based resin is 63 to 72 mass%.

4. The molding resin composition according to claim 1, 2 or 3, wherein the acrylic resin is a polymer of methyl (meth) acrylate.

5. The molding resin composition according to claim 1, 2, 3 or 4, wherein the impact resistance improver is a methyl methacrylate-butadiene-styrene copolymer.

6. The molding resin composition according to claim 1, 2, 3, 4 or 5, wherein the ratio of the impact modifier to the acrylic processing aid, expressed as impact modifier/acrylic processing aid, is 7.0 or less.

7. The molding resin composition according to claim 1, 2, 3, 4, 5 or 6, further comprising a heat stabilizer.

8. The molding resin composition according to claim 1, 2, 3, 4, 5, 6 or 7, which is characterized by not containing a β -diketone.

9. The molding resin composition according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the heat stabilizer is contained in an amount of 0.4 to 10 parts by mass based on 100 parts by mass of the chlorinated vinyl chloride-based resin.

10. A molded article obtained by molding the resin composition for molding according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9.

Technical Field

The present invention relates to a molding resin composition capable of producing a molded article having excellent thermal stability and high impact resistance and surface smoothness, and a molded article using the molding resin composition.

Background

Conventionally, vinyl chloride resins (hereinafter referred to as PVC) have been used in a variety of fields as materials having excellent mechanical strength, weather resistance, and chemical resistance. However, the following developments have been made because of poor heat resistance: chlorinated vinyl chloride-based resins (hereinafter referred to as CPVC) having improved heat resistance are obtained by chlorinating PVC. PVC has a low heat distortion temperature and a usable upper limit temperature of about 60 to 70 ℃ and is therefore unusable for hot water, while CPVC has a heat distortion temperature 20 to 40 ℃ higher than that of PVC and is therefore usable for hot water, and is suitable for heat-resistant pipes, heat-resistant joints, heat-resistant valves, heat-resistant plates, and the like.

However, CPVC has a disadvantage that the surface (inner surface) of a molded article, for example, a pipe is poor in smoothness because it has a higher viscosity and a longer stress relaxation time than general PVC. When the smoothness of the inner surface of the pipe is poor, stagnation is likely to occur due to the influence of the irregularities, and propagation of bacteria and accumulation of dirt are likely to occur, and therefore, it is difficult to use the pipe in ultrapure water piping and liner pipes for plant facilities.

On the other hand, it is conceivable to add a metal compound, a stabilizer, or the like to improve the thermal stability of CPVC, increase the molding temperature to perform molding, or increase the residence time in the mold to perform molding, thereby imparting surface smoothness.

For example, patent document 1 discloses CPVC prepared by blending an organotin stabilizer, an oxidized polyethylene wax, a modifier, a lubricant, a processing aid, a pigment, and the like at a specific ratio.

However, in the method of patent document 1, thermal stability becomes insufficient. Therefore, the operation of adding a large amount of heat stabilizer is performed, but the heat resistance originally possessed is impaired. Further, the operation using a low molecular weight processing aid was performed in order not to impair thermal stability, but a product satisfying smoothness of the inner surface could not be obtained.

Further, patent document 2 describes a method for obtaining a molded article having excellent heat resistance and smoothness by molding the article using CPVC having a chlorine content, a void ratio, and a void volume of 0.001 to 0.1 μm within a predetermined range.

However, this method has a problem that the production process of the raw material resin becomes complicated.

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide a molding resin composition that can produce a molded article having excellent thermal stability and high impact resistance and surface smoothness, and a molded article using the molding resin composition.

Means for solving the problems

The present invention is a molding resin composition comprising a chlorinated vinyl chloride resin, an acrylic processing aid and an impact resistance improver, wherein the acrylic processing aid comprises an acrylic resin having a weight average molecular weight of 50 to 500 ten thousand, and the acrylic processing aid is contained in an amount of 0.2 to 10 parts by mass and the impact resistance improver is contained in an amount of 0.5 to 8.0 parts by mass, based on 100 parts by mass of the chlorinated vinyl chloride resin.

The present invention is described in detail below.

The inventors of the present invention have conducted extensive studies and found that: the present inventors have completed the present invention by adding predetermined amounts of an impact resistance improver and an acrylic processing aid containing an acrylic resin having a predetermined weight average molecular weight to a molding resin composition containing a chlorinated vinyl chloride resin, thereby producing a molded article having excellent thermal stability and high impact resistance and surface smoothness.

In particular, the present invention can reduce the filter waviness in addition to reducing the surface roughness of the obtained molded body. Since the internal corrugation degree of the tubular member is deeply related to the fluidity, the corrugated degree of the filter can be suppressed in the molded article obtained by using the molding resin composition of the present invention, and as a result, the variation in the wall thickness is small and a uniform wall thickness can be obtained, and the internal pressure creep performance can be improved for a long period of time.

The molding resin composition of the present invention contains a chlorinated vinyl chloride resin (hereinafter also referred to as "CPVC").

The CPVC has structural units (a) to (c) represented by the following formulae (a) to (c), and the proportion of the structural unit (a) is preferably 17.5 mol% or less, the proportion of the structural unit (b) is preferably 46.0 mol% or more, and the proportion of the structural unit (c) is preferably 37.0 mol% or less, based on the total mole number of the structural units (a), (b), and (c). The CPVC has high thermal stability and good forming processability.

[ solution 1]

-CCl₂- (a)

-CHCl- (b)

-CH₂- (c)

The molar ratio of the constituent units (a), (b) and (c) of the CPVC reflects the site where chlorine is introduced when the vinyl chloride resin (PVC) is chlorinated. Ideally, PVC before chlorination is in a state where the structural unit (a), the structural unit (b), and the structural unit (c) are substantially 0 mol%, 50.0 mol%, and 50.0 mol%, respectively, but the structural unit (c) decreases with chlorination, and the structural unit (b) and the structural unit (a) increase. In this case, when the number of structural units (a) which are unstable due to large steric hindrance is excessively increased or chlorinated sites and non-chlorinated sites are present in the same particle of CPVC, the unevenness in the chlorinated state becomes large. If this inhomogeneity becomes large, the thermal stability of the CPVC is significantly impaired.

On the other hand, in the present invention, by setting the molar ratio of the constituent units (a), (b), and (c) of the CPVC to be within the above range, the CPVC becomes highly uniform and has good thermal stability.

In the present invention, the proportion of the structural unit (a) is 17.5 mol% or less based on the total mole number of the structural units (a), (b) and (c), but the proportion of the structural unit (a) is preferably 16.0 mol% or less. Further, it is preferably 2.0 mol% or more.

The proportion of the structural unit (b) is 46.0 mol% or more based on the total mole number of the structural units (a), (b), and (c), but the proportion of the structural unit (b) is preferably 53.5 mol% or more. Further, it is preferably 70.0 mol% or less.

Further, the proportion of the structural unit (c) is 37.0 mol% or less with respect to the total mole number of the structural units (a), (b), and (c), but the proportion of the structural unit (c) is preferably 30.5 mol% or less. Further, it is preferably 1.0 mol% or more.

In the present invention, it is particularly preferable that the proportion of the structural unit (b) is 58.0 mol% or more and the proportion of the structural unit (c) is 35.8 mol% or less. With such a configuration, higher thermal stability can be obtained.

The molar ratio of the structural units (a), (b), and (c) of CPVC can be measured by molecular structure analysis using NMR. NMR analysis was carried out according to the method described in R.A. Komoroski, R.G. Parker, J.PShocker, Macromolecules, 1985, 18, 1257-1265.

The PVC moiety of the CPVC, which is not chlorinated, in the molecular structure thereof can be represented by a structural unit (d) represented by the following formula (d), and is referred to as a VC unit in the present specification.

The content of VC units in the molecular structure of the CPVC used in the present invention, which are not less than the quadruplex region, is preferably not more than 30.0 mol%. Here, VC units above the quadruplex region refer to a portion to which 4 or more VC units are continuously bonded.

[ solution 2]

-CH₂-CHCl- (d)

When the VC units present in the CPVC become starting points of HCl elimination and the VC units are continuous, a continuous HCl elimination reaction called a zipper reaction easily occurs. That is, as the amount of VC units in the four-chain region or more increases, HCl desorption is more likely to occur, and thermal stability in CPVC decreases. Therefore, the VC unit in the four-chain region or more is preferably 30.0 mol% or less, and more preferably 28.0 mol% or less. When the chlorine content in the CPVC is 69 mass% or more and less than 72 mass%, the VC unit in the quadruplex region or more is preferably 18.0 mol% or less, and more preferably 16.0 mol% or less.

The content of vinyl chloride units in the four-chain region or more contained in the molecular structure can be measured by molecular structure analysis using NMR.

The chlorine content of the CPVC is preferably 63-72 mass%.

The heat resistance of the molded article is sufficient by setting the chlorine content to 63 mass% or more, and the moldability is improved by setting the chlorine content to 72 mass% or less.

The chlorine content is more preferably 66 mass% or more, and still more preferably 69 mass% or less.

The chlorine content in the CPVC can be measured by the method described in JIS K7229.

The gelling time of the CPVC is preferably 100 to 200 seconds. More preferably 110 to 190 seconds.

When the gelation time is within the above range, the resin is appropriately dispersed and fused, and the appearance and physical properties can be improved during molding.

The gelation time is: the sample in which the thermal stabilizer, lubricant, and impact modifier were added to CPVC was subjected to rotor rotation by LABO plastics or the like, and the motor torque was the most increased time.

The UV absorbance of the CPVC at a wavelength of 216nm is preferably 8.0 or less, and more preferably 0.8 or less.

In addition, in the ultraviolet absorption spectrum, the wavelength of 216nm is a wavelength at which — CH ═ CH — C (═ O) -and-CH ═ CH — CH ═ CH-in the CPVC, which are heterogeneous structures, show absorption.

The value of the UV absorbance of CPVC can be used as an index for thermal stability by quantifying the amount of a different structure in the molecular chain during the chlorination reaction. In the molecular structure of CPVC, chlorine atoms carried by carbons adjacent to the carbon forming a double bond are unstable. Therefore, the chlorine atom is used as the starting point to generate HCl removal. That is, as the value of UV absorbance at a wavelength of 216nm is larger, HCl elimination is more likely to occur, and thermal stability is lowered.

In particular, when the chlorine content of the CPVC is 63 mass% or more and less than 69 mass%, the value of UV absorbance is preferably 0.8 or less. When the value of UV absorbance exceeds 0.8, the influence of the heterogeneous structure in the molecular chain becomes large, and as a result, the thermal stability may be lowered.

When the chlorine content of the CPVC is 69 mass% or more and 72 mass% or less, the value of UV absorbance is preferably 8.0 or less. When the value of the UV absorbance exceeds 8.0, the influence of the heterogeneous structure in the molecular chain becomes large, and the thermal stability is lowered.

The time required for HCl removal at 190 ℃ of the CPVC to reach 7000ppm is preferably 60 seconds or longer, and more preferably 100 seconds or longer.

The CPVC generates HCl gas when thermally decomposed at a high temperature. In general, as the chlorination degree of CPVC becomes higher, the VC unit decreases, and therefore, the HCl desorption amount tends to decrease. However, as the degree of chlorination increases, the heterogeneous chlorinated state and heterogeneous structure increase, and the thermal stability decreases. Therefore, by measuring the amount of HCl removal, it is possible to analyze the uneven chlorination state and the increase in the heterogeneous structure. For example, the time required for the HCl elimination amount at 190 ℃ to become 7000ppm can be used as an index of thermal stability, and the shorter the time, the lower the thermal stability.

In particular, when the chlorine content of the CPVC is 63 mass% or more and less than 69 mass%, the time required for the HCl removal amount at 190 ℃ to reach 7000ppm is preferably 60 seconds or more. If the time is less than 60 seconds, thermal stability is greatly impaired. Therefore, the time is preferably 60 seconds or longer, more preferably 70 seconds or longer, and further preferably 80 seconds or longer.

When the chlorine content of the CPVC is 69 mass% or more and 72 mass% or less, the time is preferably 100 seconds or more. If the time is less than 100 seconds, the thermal stability is greatly lowered, and therefore, it is preferably 100 seconds or more, more preferably 120 seconds or more, and further preferably 140 seconds or more.

The time required for the HCl desorption at 190 ℃ to reach 7000ppm can be determined as follows. First, 1g of chlorinated vinyl chloride resin was put into a test tube, heated at 190 ℃ using an oil bath, and the generated HCl gas was recovered. The recovered HCl gas was dissolved in 100ml of ion-exchanged water, and the pH was measured. The HCl concentration (ppm) was calculated based on the pH (i.e., several g of HCl was generated per 100 ten thousand g of chlorinated vinyl chloride-based resin). The time until the HCl concentration reached 7000ppm was measured.

The CPVC is a chlorinated vinyl chloride resin (PVC).

As the PVC, a vinyl chloride homopolymer, a copolymer of a monomer having an unsaturated bond copolymerizable with a vinyl chloride monomer and a vinyl chloride monomer, a graft copolymer obtained by graft-copolymerizing a vinyl chloride monomer to a polymer, and the like can be used. These polymers may be used alone, or 2 or more of them may be used in combination.

Examples of the monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer include α -olefins, vinyl esters, vinyl ethers, (meth) acrylates, aromatic ethylenes, halogenated ethylenes, and N-substituted maleimides, and 1 or 2 or more of them can be used.

Examples of the α -olefins include ethylene, propylene, and butene.

Examples of the vinyl esters include vinyl acetate and vinyl propionate.

Examples of the vinyl ethers include butyl vinyl ether and cetyl vinyl ether.

Examples of the (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, butyl acrylate, and phenyl methacrylate.

Examples of the aromatic vinyl include styrene and α -methylstyrene.

Examples of the halogenated ethylenes include vinylidene chloride and vinylidene fluoride.

Examples of the N-substituted maleimide include N-phenylmaleimide and N-cyclohexylmaleimide.

The polymer to be graft-copolymerized with vinyl chloride is not particularly limited as long as vinyl chloride is graft-polymerized. Examples thereof include ethylene copolymers, acrylonitrile-butadiene copolymers, polyurethanes, chlorinated polyethylenes, and chlorinated polypropylenes. These may be used alone, or 2 or more of them may be used in combination.

Examples of the ethylene copolymer include an ethylene-vinyl acetate copolymer, an ethylene-vinyl acetate-carbon monoxide copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-butyl acrylate-carbon monoxide copolymer, an ethylene-methyl methacrylate copolymer, and an ethylene-propylene copolymer.

The average polymerization degree of the PVC is not particularly limited, but is preferably 400 to 3000, more preferably 600 to 1500, which is generally used. The average polymerization degree can be determined by JIS K6720-2: 1999, the measurement was carried out by the method described in.

The polymerization method of the PVC is not particularly limited, and conventionally known aqueous suspension polymerization, bulk polymerization, solution polymerization, emulsion polymerization, and the like can be used.

The molding resin composition of the present invention contains an acrylic processing aid containing an acrylic resin having a weight average molecular weight of 50 to 500 ten thousand.

Examples of the acrylic resin include homopolymers of acrylic acid, methacrylic acid, and (meth) acrylic acid esters, and (meth) acrylic copolymers containing these.

Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and the like. Examples of the (meth) acrylic acid esters include n-pentyl (meth) acrylate, isopentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and n-octyl (meth) acrylate. Wherein the (meth) acrylic acid represents acrylic acid or methacrylic acid. In the present invention, as the acrylic resin, a polymer of methyl (meth) acrylate (MMA) is preferably used.

In the above-mentioned (meth) acrylic copolymer, as other copolymerizable monomers copolymerizable with (meth) acrylic acid and (meth) acrylic acid esters, styrene, α -methylstyrene, vinyltoluene, acrylonitrile, methacrylonitrile, vinyl acetate and the like can be mentioned.

These comonomers may be present in the acrylic resin in the form of random copolymers, graft copolymers, block copolymers.

The weight average molecular weight of the acrylic resin is 50 to 500 ten thousand.

By setting the weight average molecular weight within the above range, a molded article having excellent surface smoothness can be obtained.

The lower limit of the weight average molecular weight is preferably 75 ten thousand, and the upper limit is preferably 350 ten thousand.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) are measured as molecular weights in terms of polystyrene by a Gel Permeation Chromatography (GPC) method.

The glass transition temperature of the acrylic resin is preferably 80 to 120 ℃.

Thus, a molded article having excellent surface properties without impairing the heat resistance of CPVC can be obtained.

The melting temperature of the acrylic resin is preferably 90 to 150 ℃.

Thus, a molded article having excellent surface properties without impairing the heat resistance of CPVC can be obtained.

The melting temperature can be measured by a method in accordance with JIS K7210A (measuring the flow start temperature by raising the temperature from 80 ℃ at 5 ℃/min) using a machine such as a flow tester.

In the molding resin composition of the present invention, the content of the acrylic processing aid is 0.2 to 10 parts by mass with respect to 100 parts by mass of the chlorinated vinyl chloride resin. When the acrylic processing aid is contained in this range, the surface smoothness of the resulting molded article can be further improved, and in particular, a product having a small filter waviness can be produced.

The lower limit of the content of the acrylic processing aid is preferably 0.8 part by mass, more preferably 1.0 part by mass, and the upper limit is preferably 7.5 parts by mass, more preferably 5 parts by mass.

The content of the acrylic processing aid is preferably 150 to 650 parts by mass per 100 parts by mass of the heat stabilizer.

Further, the content of the acrylic processing aid is preferably 0.4 to 7.0% by mass based on the entire molding resin composition of the present invention.

The molding resin composition of the present invention contains an impact modifier.

The impact modifier is used for the purpose of improving the impact resistance of the molded article obtained, and contains a rubber component. The impact modifier is different from the acrylic processing aid.

Examples of the impact modifier include a copolymer of a (meth) acrylate monomer component and a rubber component, and a silicone acrylic rubber containing a (meth) acrylate monomer component and an organosiloxane monomer component.

Examples of the (meth) acrylate monomer component include alkyl (meth) acrylates having 1 to 12 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethyl (meth) acrylate, and 2-ethylhexyl methacrylate. These monomer components may be used alone, or 2 or more (for example, 3) monomers may be used in combination.

The content of the (meth) acrylate monomer component in the polymer constituting the impact modifier is not particularly limited, and is preferably, for example, 20 to 40% by mass.

The rubber component may be any of a diene component and a non-diene component, and may be a homopolymer or a copolymer (including a binary copolymer and a ternary copolymer). As the copolymer, random copolymerization, alternating copolymerization, block copolymerization and graft copolymerization may be mentioned.

Examples of the diene component include butadiene, isoprene, and chloroprene. Further, a copolymer containing a monomer component selected from the group consisting of a diene, an unsaturated nitrile, an α -olefin and an aromatic vinyl may be mentioned. More specifically, there may be mentioned a copolymer of an unsaturated nitrile and a diene (for example, an acrylonitrile-butadiene copolymer), a copolymer of an aromatic vinyl and a diene (for example, a butadiene-styrene copolymer, a styrene-isoprene copolymer), a copolymer of an olefin and a diene (for example, an ethylene-propylene-diene copolymer), and the like.

The content of the diene component in the polymer constituting the impact modifier is preferably 35 to 70% by mass, and more preferably 50 to 65% by mass.

Examples of the non-diene component include polymers containing 1 or 2 or more monomer components selected from olefins and organosiloxanes. More specifically, olefin rubbers (e.g., ethylene-propylene rubbers) and silicone acrylic rubbers are exemplified.

More specifically, methyl methacrylate-butadiene-styrene copolymer (MBS), acrylonitrile-butadiene-styrene copolymer (ABS), methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS), methyl methacrylate-butadiene copolymer (MB), and the like are preferably used as the impact modifier.

Further, as the impact modifier, a methyl methacrylate-acrylic butadiene rubber copolymer, a methyl methacrylate-acrylic butadiene rubber-styrene copolymer, and a methyl methacrylate- (acrylic silicone composite) copolymer are preferably used. Among them, methyl methacrylate-butadiene-styrene copolymer and/or acrylonitrile-butadiene-styrene copolymer are preferable.

Among the constituent components of the impact modifier, the glass transition temperature of the monomer of the resin contributing to the impact resistance effect is preferably less than 0 ℃. This can improve impact resistance without impairing heat resistance of the resulting molded article.

In the molding resin composition of the present invention, the content of the impact modifier is 0.5 to 8 parts by mass per 100 parts by mass of the chlorinated vinyl chloride-based resin. When the impact modifier is contained in this range, the impact resistance of the molded article obtained can be further improved.

The lower limit of the content of the impact modifier is preferably 3 parts by mass, more preferably 4 parts by mass, and the upper limit is preferably 8 parts by mass, more preferably 7.5 parts by mass.

Further, the content of the impact modifier is preferably 2.5 to 6.0% by mass based on the entire molding resin composition of the present invention.

In the molding resin composition of the present invention, the ratio of the impact resistance improver to the acrylic processing aid (impact resistance improver/acrylic processing aid) is preferably 7.0 or less. By setting the content within such a range, a molded article having both good appearance and impact resistance can be obtained.

The impact modifier/acrylic processing aid is preferably 0.7 to 7.0, more preferably 0.7 to 4.0.

The impact modifier is preferably in the form of particles, and the average particle diameter is preferably small. The average particle diameter of the impact modifier particles is preferably about 0.1 to 200 μm.

The molding resin composition of the present invention preferably further contains a heat stabilizer.

In the present invention, the heat stabilizer is preferably an organotin stabilizer. In addition, a heat stabilizer containing calcium alkylcarboxylate and a zinc compound is preferably used.

Examples of the organotin stabilizers include alkyl tin such as methyl, butyl and octyl; preferred examples thereof include salts of aliphatic monocarboxylic acids such as lauric acid of dialkyltin, and salts of dicarboxylic acids such as maleic acid and phthalic acid. Specific examples thereof include dibutyltin dilaurate, dioctyltin laurate, dibutyltin maleate, dibutyltin phthalate, dimethyltin bis (2-ethylhexylthioglycolate), dibutyltin mercaptide, dimethyltin mercaptide and the like.

Since the heat stabilizer containing the calcium alkylcarboxylate and the zinc compound does not contain a heavy metal, a resin composition for molding which is free from a heavy metal can be obtained.

In addition, when such a thermal stabilizer is used, hydrochloric acid generated by thermal decomposition of the chlorinated vinyl chloride-based resin immediately reacts with a zinc compound to form zinc chloride. Further, the growth of polyene produced by the desalting of chlorinated vinyl chloride resin is stopped by the binding thereof with calcium alkylcarboxylate, thereby suppressing color development.

On the other hand, the zinc chloride produced has a property of promoting thermal decomposition of the chlorinated vinyl chloride resin, but in the present invention, the zinc chloride reacts with calcium alkylcarboxylate to produce calcium chloride and zinc alkylcarboxylate. As a result, the above-mentioned thermal stabilizer has a remarkable synergistic effect because the action of the zinc compound to rapidly capture hydrochloric acid is utilized and the action of zinc chloride to promote thermal decomposition is suppressed.

Examples of the calcium alkylcarboxylate include calcium salts of valeric acid, caproic acid, heptanoic acid, caprylic acid, cyclohexylpropionic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, arachidic acid, behenic acid, lignoceric acid, montanic acid, and the like.

Among them, calcium alkylcarboxylates having 8 to 28 carbon atoms are preferably used.

Examples of the zinc compound include an inorganic zinc compound and an organic zinc compound.

Examples of the inorganic zinc compound include compounds derived from a system including a carbonate, a chloride, a sulfate, an oxide, a hydroxide, a basic oxide, and a mixed oxide of zinc.

Examples of the above-mentioned organozinc compound include an alkylzinc compound such as dialkylzinc and/or monoalkylzinc, an organoaliphatic zinc carboxylate, an unsubstituted or substituted organoaromatic zinc carboxylate, an organozinc phosphite, a substituted or unsubstituted zinc phenoxide, a zinc amino acid or its derivative, and a zinc organothiolate.

Examples of the organic aliphatic carboxylic acid constituting the organic aliphatic carboxylic acid zinc include montanic acid, rice bran fatty acid, behenic acid, erucic acid, stearic acid, oleic acid, linoleic acid, rice fatty acid, ricinoleic acid, myristic acid, palmitic acid, lauric acid, lower fatty acid, caprylic acid, isostearic acid, dimer acid, naphthenic acid, and acetic acid.

The organic aliphatic carboxylic acid may include, in addition to dicarboxylic acids such as azelaic acid, sebacic acid, adipic acid, succinic acid, malonic acid, maleic acid, crotonic acid, malic acid, and tartaric acid, monoesters thereof.

Further, examples of the organic aliphatic carboxylic acid include citric acid and its monoester or diester, lactic acid, glycolic acid, thiodipropionic acid and its monoester, and the like.

Examples of the unsubstituted or substituted aromatic carboxylic acid constituting the unsubstituted or substituted organic aromatic carboxylic acid zinc include benzoic acid, o-toluic acid, m-toluic acid, p-tert-butylbenzoic acid, p-hydroxybenzoic acid, salicylic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and monoesters or diesters thereof.

Examples of the organic phosphorous acid constituting the organic zinc phosphite include acid phosphites which are reaction products of aliphatic alcohols and phosphorus pentoxide. Specific examples thereof include butyl acid phosphite, octyl acid phosphite, stearyl acid phosphite, and behenyl acid phosphite.

Examples of the substituted or unsubstituted phenol constituting the above-mentioned substituted or unsubstituted zinc phenol include phenol, cresol, mixed xylene, octylphenol, nonylphenol, dinonylphenol, cyclohexylphenol and phenylphenol. Examples of the substituted or unsubstituted phenol include bisphenol a, bisphenol S, bisphenol F, esters of p-hydroxybenzoic acid, and esters of salicylic acid.

Examples of the amino acid and its derivative include calcined glutamic acid, glycine, alanine, and the like.

Examples of the organic thiol constituting the zinc organosulfurol include lauryl thiol, thioglycolic acid and esters thereof, mercaptopropionic acid and esters thereof, and thiomalic acid and monoesters or diesters thereof.

The heat stabilizer contains calcium alkylcarboxylate and a zinc compound, and is preferably a mixture of the calcium alkylcarboxylate and the zinc compound.

Examples of the form of the heat stabilizer include powder and granular form. By forming the heat stabilizer in this form, the heat stabilizer can be used as a one pack (one pack).

When the heat stabilizer is a powder or granule, the particle size thereof can be arbitrarily adjusted according to the purpose, and generally, the average particle size is preferably 50 μm to 5mm, particularly preferably 70 μm to 2 mm.

As a method for producing the heat stabilizer for the granular material, for example, a known granulation method itself, such as an extrusion granulation method, a spray granulation method, a rotary disk granulation method, a rotary granulation method, or a compression granulation method, can be used.

The heat stabilizer preferably has a heat loss rate of less than 5% by mass at 230 ℃.

When the heat loss rate at 230 ℃ is 5% by mass or more, the strength of the molded article may be insufficient due to the inclusion of air bubbles therein, or a striped pattern may be formed in the vicinity of the surface of the molded article, resulting in appearance defects.

The heat loss rate at 230 ℃ is more preferably less than 3% by mass.

The lower limit is not particularly limited, but is preferably 0.1% by mass.

The heat loss rate at 230 ℃ can be measured by a Thermogravimetry (TG) apparatus.

The heat stabilizer contains calcium alkylcarboxylate and a zinc compound, and the mixing ratio of the calcium alkylcarboxylate to the zinc compound (calcium alkylcarboxylate: zinc compound) is preferably 9: 1 to 4: 6. Further, the mixing ratio is more preferably 8: 2 to 5: 5.

In the molding resin composition of the present invention, the content of the heat stabilizer is preferably 0.4 to 10 parts by mass, more preferably 0.6 to 7 parts by mass, based on 100 parts by mass of the chlorinated vinyl chloride-based resin. When the heat stabilizer is contained in this range, the heat stability can be further improved and the good appearance of the molded article can be maintained.

When a heat stabilizer containing calcium alkylcarboxylate and a zinc compound is used as the heat stabilizer, a molding resin composition free of heavy metal can be obtained.

In the present specification, heavy metal refers to a metal having a high density, and generally refers to a metal having a density of 4 to 5g/cm³The above metals. The term "free of heavy metals" means that the content of heavy metals is 1000ppm or less. The content of the heavy metal is preferably 100ppm or less.

Examples of the heavy metal include transition metals other than scandium, and examples thereof include Mn, Ni, Fe, Cr, Co, Cu, and Au. Further, metals (for example, Sn, Pb, Bi), Cd, Hg, and the like of p-block elements in the fourth period or less are also included.

The molding resin composition of the present invention preferably further contains an antioxidant.

As the antioxidant, for example, a phenol-based antioxidant, a phosphate-based antioxidant, a sulfur-based antioxidant, an amine-based antioxidant, and the like can be used. These may be used alone or in combination of two or more. Among these, phenol antioxidants are preferable, and hindered phenol antioxidants are particularly preferable.

Examples of the hindered phenol-based antioxidant include 2, 6-di-t-butyl-p-cresol, 2, 6-diphenyl-4-octadecyloxyphenol, stearyl (3, 5-t-butyl-4-hydroxyphenyl) propionate, distearyl (3, 5-t-butyl-4-hydroxybenzyl) phosphonate, 2 '-methylenebis (4-methyl-6-t-butylphenol), 2' -methylenebis (4-ethyl-6-t-butylphenol), bis [ 3, 3-bis (4-hydroxy-3-t-butylphenyl) butyrate ] diol, 4 '-butylidenebis (6-t-butyl-m-cresol), 2' -ethylidenebis (4, 6-di-t-butylphenol), 2, 2' -ethylidenebis (4-sec-butyl-6-tert-butylphenol), 1, 3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, bis [ 2-tert-butyl-4-methyl-6- (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl ] terephthalate, 1, 3, 5-tris (2, 6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate, 1, 3, 5-tris (3, 5-di-tert-butyl-4-hydroxybenzyl) -2, 4, 6-trimethylbenzene, 1, 3, 5-tris [ (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl ] isocyanurate, pentaerythritol-tetrakis [ methylene-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], 2-tert-butyl-4-methyl-6- (2 '-acryloyloxy-3' -tert-butyl-5 '-methylbenzyl) phenol, 3, 9-bis (1', 1 '-dimethyl-2' -hydroxyethyl) -2, 4, 8, 10-tetraoxaspiro [ 5, 5] undecane, bis [ beta- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate ], and the like. Among these, 1, 3, 5-tris (3, 5-di-t-butyl-4-hydroxybenzyl) isocyanurate, pentaerythritol-tetrakis [ methylene-3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ], and the like are preferable. These may be used alone, or 2 or more of them may be used in combination.

The heat loss rate of the antioxidant at 200 ℃ is preferably less than 5% by mass.

When the heating loss rate at 200 ℃ is 5% by mass or more, bubbles are contained in the molded article and the strength becomes insufficient, or a striped pattern is generated in the vicinity of the surface and appearance defects are generated in some cases.

The rate of heat loss at 200 ℃ is preferably less than 3% by mass.

In the molding resin composition of the present invention, the content of the antioxidant is preferably in the range of 0.1 to 3 parts by mass, more preferably 0.2 to 2.5 parts by mass, per 100 parts by mass of the chlorinated vinyl chloride-based resin. By including the antioxidant in this range, a molded article with less coloration due to yellowing can be obtained.

The molding resin composition of the present invention preferably further contains a stabilizing assistant. By including the above-mentioned stabilizing assistant, thermal stability can be further improved.

As the above-mentioned stabilizing assistant, a stabilizing assistant not containing heavy metals can be used. Examples thereof include organic acid salts, epoxy compounds, phosphoric acid compounds, metal hydroxides, sodium adipate, glycidyl (meth) acrylate copolymers, oxetane compounds, vinyl ether compounds and zeolite compounds.

Examples of the epoxy compound include epoxidized soybean oil, epoxidized linseed oil, epoxidized tetrahydrophthalate, epoxidized polybutadiene, bisphenol a type epoxy compounds, and the like.

Examples of the phosphoric acid compound include organic phosphorus compounds, phosphites, phosphates, and the like.

Examples of the metal hydroxide include calcium hydroxide and sodium hydroxide.

These may be used alone, or 2 or more of them may be used in combination. The above-mentioned stabilizing assistant is different from calcium alkylcarboxylate and zinc compound.

These may be used alone, or 2 or more of them may be used in combination. The above-mentioned stabilizing assistant is different from calcium alkylcarboxylate and zinc compound.

Further, the heating decrement of the above-mentioned stabilizing assistant at 200 ℃ is preferably less than 5% by mass.

The molding resin composition of the present invention may be mixed with additives such as a lubricant, a processing aid, a heat resistance improver, an ultraviolet absorber, a light stabilizer, a filler, a thermoplastic elastomer, and a pigment, if necessary.

Examples of the lubricant include an internal lubricant and an external lubricant. The internal lubricant is used for the purpose of reducing the flow viscosity of the molten resin during molding and preventing frictional heat generation. The internal lubricant is not particularly limited, and examples thereof include butyl stearate, lauryl alcohol, stearyl alcohol, glycerol monostearate, stearic acid, and bisamide. These may be used alone, or 2 or more of them may be used in combination.

The heating loss rate of the lubricant at 200 ℃ is preferably less than 5% by mass.

The external lubricant can be used for the purpose of improving the sliding effect between the molten resin and the metal surface during the molding process. The external lubricant is not particularly limited, and examples thereof include polyolefin waxes such as paraffin wax and polyethylene-based lubricant, ester waxes such as fatty acid ester-based lubricant, and montanic acid wax. These may be used alone, or 2 or more of them may be used in combination.

The heat resistance improver is not particularly limited, and examples thereof include an α -methylstyrene type resin, an N-phenylmaleimide type resin, and the like.

The light stabilizer is not particularly limited, and examples thereof include hindered amine light stabilizers and the like.

The ultraviolet absorber is not particularly limited, and examples thereof include salicylic acid ester-based, benzophenone-based, benzotriazole-based, cyanoacrylate-based, and the like.

The pigment is not particularly limited, and examples thereof include organic pigments such as azo-based, phthalocyanine-based, selenium-based, and dye lake-based pigments; oxide-based pigments such as titanium dioxide, sulfide-selenide-based inorganic pigments such as ferricyanide-based inorganic pigments, and the like.

The molding resin composition of the present invention may contain a plasticizer for the purpose of improving processability during molding, and the use of a large amount of the plasticizer is not preferred because the thermal stability of a molded article may be lowered. The plasticizer is not particularly limited, and examples thereof include dibutyl phthalate, di-2-ethylhexyl adipate and the like.

The molding resin composition of the present invention may contain a thermoplastic elastomer for the purpose of improving workability. Examples of the thermoplastic elastomer include nitrile thermoplastic elastomers, olefin thermoplastic elastomers, vinyl chloride thermoplastic elastomers, styrene thermoplastic elastomers, urethane thermoplastic elastomers, polyester thermoplastic elastomers, and polyamide thermoplastic elastomers.

Examples of the nitrile thermoplastic elastomer include acrylonitrile-butadiene copolymer (NBR).

Examples of the olefinic thermoplastic elastomer include ethylene thermoplastic elastomers such as ethylene-vinyl acetate copolymer (EVA) and ethylene-vinyl acetate-carbon monoxide copolymer (EVACO).

Examples of the vinyl chloride-based thermoplastic elastomer include a vinyl chloride-vinyl acetate copolymer, a vinyl chloride-vinylidene chloride copolymer, and the like.

These thermoplastic elastomers may be used alone, or two or more of them may be used in combination.

The molding resin composition of the present invention preferably contains no β -diketone. The β -diketone is a component added to a conventional heat stabilizer for the purpose of improving heat stability. However, when a heat stabilizer containing a β -diketone is used, the appearance of a molded article is easily impaired when the resin composition is molded by extrusion molding or injection molding to produce the molded article. For example, yellow to reddish brown stripes having a thickness of about 0.1 to 1mm are formed on the surface of the molded article in parallel with the flow direction of the resin. In this way, the molded body with the damaged appearance becomes a defective product. In particular, when a mold used for a long time is used, such a defective product is likely to occur. However, according to the present invention, a molding resin composition having excellent thermal stability can be provided without using a heat stabilizer containing a β -diketone.

The molding resin composition of the present invention can be produced by the following method. For example, the following method may be used, which performs the following steps: preparing a chlorinated vinyl chloride-based resin by suspending a vinyl chloride-based resin in an aqueous medium in a reaction vessel to prepare a suspension, introducing chlorine into the reaction vessel, and chlorinating the vinyl chloride-based resin by any conventionally known method; then, the method comprises the following steps: and a step of adding a predetermined amount of an acrylic processing aid and an impact resistance improver, each of which comprises an acrylic resin having a weight average molecular weight of 50 to 500 ten thousand, to the chlorinated vinyl chloride resin and mixing them.

As the reaction vessel used in the step of producing the chlorinated vinyl chloride-based resin, for example, a generally used vessel such as an enameled stainless steel reaction vessel or a titanium reaction vessel can be used.

The method for preparing a suspension by suspending the vinyl chloride-based resin in an aqueous medium is not particularly limited, and a cake-like PVC obtained by subjecting PVC after polymerization to a monomer removal treatment may be used, or a dried product may be resuspended in an aqueous medium. Further, a suspension obtained by removing substances unsuitable for chlorination reaction from the polymerization system may be used, but a cake-like resin obtained by subjecting PVC after polymerization to a demonomerization treatment is preferably used.

As the aqueous medium, for example, ion-exchange-treated pure water can be used. The amount of the aqueous medium is not particularly limited, and is preferably 150 to 400 parts by mass per 100 parts by mass of PVC.

The chlorine introduced into the reaction vessel may be either liquid chlorine or gaseous chlorine. In order to inject a large amount of chlorine in a short time, it is effective to use liquid chlorine. Chlorine may be added during the reaction to adjust the pressure or to replenish chlorine. In this case, gaseous chlorine may be appropriately blown in addition to liquid chlorine. Preferably, chlorine obtained by purifying 5 to 10 mass% of chlorine in the liquefied gas cylinder is used.

The gauge pressure in the reaction vessel is not particularly limited, and is preferably in the range of 0.3 to 2MPa since the higher the chlorine pressure is, the more likely chlorine permeates into the PVC particles.

The method for chlorinating PVC in the suspended state is not particularly limited, and examples thereof include: a method of promoting chlorination by exciting PVC bonds and chlorine by thermal energy (hereinafter referred to as thermal chlorination); and a method of promoting chlorination by photoreactivity upon irradiation with light energy such as ultraviolet light (hereinafter referred to as photochlorination). The heating method in the case of chlorination by thermal energy is not particularly limited, and for example, heating from the reactor wall by an external jacket method is effective. In addition, when light energy such as ultraviolet light is used, a device capable of performing irradiation of light energy such as ultraviolet irradiation under conditions of high temperature and high pressure is required. The chlorination reaction temperature during the photochlorination is preferably 40-80 ℃.

Among the above-mentioned chlorination methods, a thermal chlorination method in which ultraviolet irradiation is not performed is preferable, and a method in which a chlorination reaction is promoted by exciting a bond or chlorine of a vinyl chloride resin with heat alone or heat and hydrogen peroxide is preferable.

In the case of the above-described chlorination reaction based on light energy, the amount of light energy required for chlorination of PVC is significantly affected by the distance between the PVC and the light source. Therefore, the surface and the inside of the PVC particles are subjected to different energies, and chlorination does not occur uniformly. As a result, CPVC with low uniformity was obtained. On the other hand, in the method of chlorination by heat without ultraviolet irradiation, a more uniform chlorination reaction can be achieved, and CPVC with high uniformity can be obtained.

When the chlorination is carried out by heating only, the temperature is preferably in the range of 70 to 140 ℃. If the temperature is too low, the chlorination rate decreases. If the temperature is too high, the HCl removal reaction occurs concurrently with the chlorination reaction, and the resulting CPVC is colored. The heating temperature is more preferably in the range of 100 to 135 ℃. The heating method is not particularly limited, and heating can be performed from the reaction vessel wall by, for example, an external jacket method.

In the chlorination, it is preferable to further add hydrogen peroxide to the suspension. The rate of chlorination can be increased by adding hydrogen peroxide. For hydrogen peroxide, it is preferable to add PVC in an amount of 5 to 500ppm per 1 hour of reaction time. If the amount of addition is too small, the effect of increasing the rate of chlorination cannot be obtained. If the amount is too large, the thermal stability of CPVC decreases.

When the hydrogen peroxide is added, the chlorination rate is increased, and thus the heating temperature can be lowered. For example, the temperature may be in the range of 65 to 110 ℃.

In the case of the chlorination, it is preferable to perform chlorination after the time when the final chlorine content reaches 5 mass% at a chlorine consumption rate of 0.010 to 0.015 Kg/PVC-Kg.5 min, and further perform chlorination after the time when the final chlorine content reaches 3 mass% at a chlorine consumption rate of 0.005 to 0.010 Kg/PVC-Kg.5 min. Here, the chlorine consumption rate means the chlorine consumption amount per 1kg of raw material PVC for 5 minutes.

By performing chlorination by the above-described method, CPVC having less unevenness in the chlorinated state and excellent thermal stability can be obtained.

In the method for producing the molding resin composition of the present invention, the following steps are performed: to the chlorinated vinyl chloride-based resin, prescribed amounts of an acrylic processing aid and an impact resistance improver comprising an acrylic resin having a weight average molecular weight of 50 to 500 ten thousand are added and mixed, and if necessary, a heat stabilizer and an antioxidant are added.

The method of mixing the heat stabilizer and the antioxidant is not particularly limited, and examples thereof include a method by hot blending and a method by cold blending.

According to the configuration of the present invention as described above, a molding resin composition having excellent thermal stability and containing no heavy metal such as lead, cadmium, or tin can be provided.

Further, according to another aspect of the present invention, there is provided a molded article molded from the molding resin composition of the present invention. Such a shaped body is also one of the present invention.

The molding method may be any conventionally known molding method, and examples thereof include extrusion molding and injection molding.

The molded article of the present invention does not contain heavy metals as in the molding resin composition of the present invention, and therefore has the excellent advantage of not adversely affecting the environment, and has excellent thermal stability and a good appearance, and therefore, can be suitably used for applications such as building parts, plumbing equipment, and housing materials.

The surface roughness (Rmax) of the molded article of the present invention is preferably 1.0 μm or less.

The average (WcA) of the center lines of the waviness of the outer surface of the molded article of the present invention is preferably 5.0 μm or less. This results in a molded body with less surface unevenness and less wall thickness variation. In the present invention, since the filter waviness center line average is small in addition to the small surface roughness, when the filter is used for a pipe or the like, friction with flowing water is reduced, and the flow velocity can be increased.

The surface roughness (Rmax) can be measured by a method according to JIS B0601, and the filter waviness center line average (WcA) can be measured by a method according to JIS B0610.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention provides a molding resin composition capable of producing a molded article having excellent thermal stability and high impact resistance and surface smoothness, and a molded article using the molding resin composition.

Detailed Description

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[ example 1]

(preparation of chlorinated vinyl chloride resin)

200kg of ion-exchanged water and 56kg of vinyl chloride resin having a polymerization degree of 1000 were put into an enameled reaction vessel having an inner volume of 300L. The mixture was stirred and further water was added to the reaction vessel to disperse the mixture in water. Then, the pressure was reduced to remove oxygen in the reaction vessel, and the temperature was raised to 90 ℃.

Then, chlorine was supplied into the reaction vessel so that the chlorine partial pressure became 0.4MPa, and a chlorination reaction was carried out while adding 0.2 mass% hydrogen peroxide at a rate of 1 part by mass per 1 hour (320 ppm/hour). The reaction was continued until the chlorine content of the chlorinated vinyl chloride resin reached 61 mass%. When the chlorine content of the chlorinated vinyl chloride resin reached 61 mass% (5 mass% before), the chlorination was performed by adjusting the average chlorine consumption rate to 0.012 kg/PVC-kg.5 min by reducing the amount of 0.2 mass% hydrogen peroxide added to 0.1 part by mass (200 ppm/hr) per 1 hour. When the chlorine content reached 63 mass% (3 mass%) the amount of 0.2 mass% hydrogen peroxide added was adjusted to 150 ppm/hr per 1 hour, and the chlorination was performed so that the average chlorine consumption rate reached 0.008 kg/PVC-kg.5 min. Thus, a chlorinated vinyl chloride-based resin having a chlorine content of 67.3 mass% was obtained. The chlorine content of the chlorinated vinyl chloride-based resin was measured in accordance with JIS K7229.

The gelation time of the chlorinated vinyl chloride-based resin was measured by the following method.

(measurement of gelation time)

A mixture sample was prepared by adding and mixing 1.2 parts by mass of a heat stabilizer, 1.0 part by mass of a polyethylene lubricant, 0.5 part by mass of an oxidized polyethylene lubricant, and 5.5 parts by mass of an impact modifier to 100 parts by mass of a chlorinated vinyl chloride resin. The following were used as a heat stabilizer, a polyethylene lubricant, an oxidized polyethylene lubricant, and an impact modifier.

Heat stabilizer (TVS #1380 manufactured by Nindong chemical industry Co., Ltd.)

Polyethylene lubricant (Hiwax 220MP, Mitsui chemical Co., Ltd.)

Oxidized polyethylene type lubricant (A-C316A, product of Honeywell Co., Ltd.)

Impact modifier (KANEACE M-511 manufactured by KANEKA Co., Ltd.)

Next, 59g of the mixture sample was put into LABO PLASTOMIL (4C 150, manufactured by Toyo Seiki Seisaku-Sho Ltd.) at a temperature of 180 ℃ and preheated for 80 seconds, and then the rotor was rotated at a rotational speed of 30rpm, and the time when the motor torque was most increased was defined as the gelation time.

(preparation of chlorinated vinyl chloride resin composition)

To 100 parts by mass of the obtained chlorinated vinyl chloride-based resin (polymerization degree: 1000), 1.5 parts by mass of polymethyl methacrylate (weight average molecular weight: 80 ten thousand, glass transition temperature: 75 ℃, melting temperature: 136 ℃) and 5.5 parts by mass of an impact modifier were added as acrylic processing aids. Further, 1.5 parts by mass of a heat stabilizer and 0.5 part by mass of pentaerythritol tetrakis [ 3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ] (hindered phenol antioxidant Irganox 1010, manufactured by BASF corporation, heat loss at 200 ℃ C.: 1.0 mass%) as an antioxidant were added and mixed. As the impact modifier, MBS-1 (methyl methacrylate-butadiene-styrene copolymer, methyl methacrylate content: 25% by mass, diene content: 55% by mass, average particle diameter: 0.3 μm) resin (manufactured by LG chemical company, glass transition temperature of butadiene monomer: 93 ℃ C.) was used. Further, as the heat stabilizer (organotin stabilizer), dimethyl tin bis (2-ethylhexyl thioglycolate) was used.

Further, 2.0 parts by mass of a polyethylene-based lubricant (Hiwax 220MP, manufactured by Mitsui chemical Co., Ltd.), 0.3 part by mass of a fatty acid ester-based lubricant (LOXIOLG-32, manufactured by Emery Oleo Chemicals Japan Co., Ltd.), and 6.0 parts by mass of titanium dioxide (TIPAQUE CR-90, manufactured by Stone Ltd.) were added. Thereafter, the mixture was uniformly mixed by a super mixer to obtain a chlorinated vinyl chloride resin composition.

(production of extrusion molded article)

The chlorinated vinyl chloride-based resin composition thus obtained was fed to a twin-screw counter-rotating conical extruder (manufactured by Yangtze Kabushiki Kaisha, "SLM-50") having a diameter of 50mm, and the resin temperature and back pressure were set at 209.8 ℃ and 291.0kg/cm²Under the condition that the extrusion amount was 24.3kg/hr, a tubular molded article having an inner diameter of 20mm and a thickness of 3mm was produced.

Examples 2 to 14 and comparative examples 1 to 6

A chlorinated vinyl chloride-based resin composition and an extrusion molded article were produced in the same manner as in example 1, except that polymethyl methacrylate having a weight average molecular weight (Mw) and a melting temperature shown in table 1 and an impact modifier were used in the amounts shown in table 1. In example 11, ABS (Blendex 338, acrylonitrile-butadiene-styrene copolymer, manufactured by Galata Chemicals) resin was used as the impact modifier.

In examples 12 and 13, calcium stearate and zinc stearate were used instead of dimethyl tin bis (2-ethylhexylthioglycolic acid).

Furthermore, in example 14, MBS-2 (methyl methacrylate-butadiene-styrene copolymer, methyl methacrylate content: 25% by mass, diene content: 40% by mass, average particle diameter: 0.3 μm) was used instead of MBS-1.

The conditions in the extrusion molding were changed to the conditions shown in table 1.

[ example 15]

A chlorinated vinyl chloride-based resin composition and an extrusion-molded article were produced in the same manner as in example 1, except that a chlorinated vinyl chloride-based resin having a gelation time shown in table 1 was used.

< evaluation >

The following evaluations were made with respect to the chlorinated vinyl chloride-based resin compositions and molded articles obtained in examples and comparative examples. The results are shown in Table 1.

[ evaluation of chlorinated vinyl chloride resin composition ]

< mechanical Properties (IZOD impact Strength, tensile elastic modulus, Heat distortion temperature) >

The chlorinated vinyl chloride-based resin composition thus obtained was fed to two 8-inch rolls, and kneaded at 205 ℃ for 3 minutes to prepare a sheet having a thickness of 1.0 mm. The obtained sheets were superposed, preheated for 3 minutes by pressing at 205 ℃ and then pressed for 4 minutes to obtain a pressed sheet having a thickness of 3 mm. Test pieces were cut out of the resulting pressboards by machining. Using the test piece, IZOD impact strength was measured in accordance with ASTM D256, and tensile strength and tensile modulus of elasticity were measured in accordance with ASTM D638. Further, according to ASTM D648 at 186N/cm²The heat distortion temperature was measured. The heat distortion temperature was measured after annealing the obtained pressed plate for 24 hours in a gill oven at 90 ℃.

< Vicat softening temperature >

By the method according to JIS K7206: 2016 (method B50 for calculating Vicat Softening Temperature (VST) of Plastic-thermoplastic) by measuring Vicat softening temperature.

[ evaluation of molded article ]

< appearance Observation >

The surface state of the obtained tubular extrusion molded article was visually observed to evaluate the presence or absence of gray spots (discoloration).

< surface roughness >

The surface roughness (Rmax) was measured by a method in accordance with JIS B0601 using a surface roughness measuring apparatus (SURFCOM 480A, manufactured by tokyo precision corporation). The measurement conditions were: the evaluation length was 0.3mm, the measurement speed was 0.3mm/sec, and the cut-off value was 0.08 mm.

< degree of filter waviness >

The average center line of the filter waviness of the outer surface (filter center waviness, WcA) was measured by a method in accordance with JIS B0610 using a surface roughness measuring apparatus (SURFCOM 480A, manufactured by tokyo precision corporation). The measurement conditions were: the evaluation length is 30mm, the measurement speed is 3mm/sec, and the cut-off value is 0.25-8 mm.

[ Table 1]

Industrial applicability

The present invention provides a molding resin composition capable of producing a molded article having excellent thermal stability and high impact resistance and surface smoothness, and a molded article using the molding resin composition.