JP2002284947A - Vinyl chloride-based resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vinyl chloride-based composition capable of presenting a vinyl chloride-formed product excellent in alkali resistance. SOLUTION: This vinyl chloride-based resin composition has >=30% retention of the elongation at break calculated by the following equation (1): retention of the elongation at break = Ea/Eb×100 (1), wherein Ea expresses the elongation at break when a tensile test piece (JIS7113: test piece No.2) is immersed in a 14 wt.% aqueous KOH solution for 72 hours in a condition in which the test piece is bent in an arc shape to generate 190-200 kg/cm<2> maximum generated stress on the surface; Eb expresses the elongation at break before immersing the test piece.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a vinyl chloride resin composition.

[0002]

2. Description of the Related Art Vinyl chloride resin (hereinafter referred to as PVC)
Is a general-purpose resin used in a wide range of fields such as water supply and drainage pipes, plates, and joints because it has excellent mechanical strength, weather resistance, and chemical resistance and is inexpensive compared to other plastic materials. However, since PVC has a low heat distortion temperature and a usable upper limit temperature of about 60 to 70 ° C., it has been difficult to use PVC for hot water supply pipes or plant pipes through which hot water flows. In order to improve the durability of PVC at high temperatures, a chlorinated vinyl chloride resin (hereinafter referred to as CPVC) has been developed in which PVC is chlorinated to improve heat resistance. Due to the compounding design using this resin, it has become possible to use a tube having both easy workability and easy adhesion of PVC, heat resistance and impact resistance. (Japanese Patent Application Laid-Open No. 4-35928) As described above, pipes having no problem in hot water supply pipes and ultrapure water pipes for plants have been developed. On the other hand, line pipes in a plant field in which an alkaline aqueous solution flows are used. Environmental stress cracking, even with hard vinyl chloride pipes with excellent chemical resistance, which progresses over time due to long-term use, and is further subjected to internal pressure, pulsation, stress generated at the support part, and stress generated by expansion and contraction. (Hereinafter referred to as ESC), and there was a case where destruction, rupture, or outflow of a chemical solution of the pipe became a problem.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a vinyl chloride resin composition from which a PVC molded article having excellent alkali resistance can be obtained.

[0004]

The vinyl chloride resin composition according to the invention described in claim 1 (hereinafter referred to as invention 1) has an elongation at break calculated by the formula (1) described in claim 1. Is 30% or more. The vinyl chloride resin composition according to the invention described in claim 2 (hereinafter, referred to as invention 2) comprises 4 parts by weight of a modifier component per 100 parts by weight of the chlorinated vinyl chloride resin.
If not less than 30 parts by weight, and if necessary, a vinyl chloride resin is added, the total of the vinyl chloride resin component and the modifier component is 10 parts by weight or more and the modifier component The vinyl chloride resin composition according to claim 1, wherein is less than 30 parts by weight. The vinyl chloride resin composition according to the invention of claim 3 (hereinafter referred to as invention 3) uses a silicone acrylic modifier as a modifier component.
It is a vinyl chloride resin composition of the description.

[0005] The ESC of a vinyl chloride resin molded article due to alkali is a phenomenon that occurs when a vinyl chloride resin composition is degraded by an alkali in contact with the vinyl chloride resin composition and when stress is generated in the vinyl chloride molded article. Either of them will not cause the phenomenon of ESC.

The inventors of the present invention have made intensive studies based on the above findings. As a result, the tensile test piece (JIS K7113: No. 2 test piece) was bent in an arc shape such that the maximum surface generated stress was 18.6 to 19.6 MPa. Elongation at break after immersion in a 14% by weight KOH aqueous solution at 50 ° C. for 72 hours (E
From a) and the elongation at break (Eb) before immersion, it is clear that when the elongation retention at break calculated by the following formula (1) is 30% or more, ESC is unlikely to occur even when an alkali is used. did. (Ea) / (Eb) × 100 (1) This is because the vinyl chloride resin composition having a retention of elongation at break of 30% or more according to the formula (1) is unlikely to cause deterioration of the material due to alkali, or has an initial property. This is because the stress generated at the time is easily relieved. As a result, it is considered that minute ESC generated on the surface of the molded article is suppressed, and a decrease in elongation at break is suppressed.

When the elongation at break calculated by the above equation (1) is less than 30%, the ESC under normal use conditions
Occurs and grows slowly. As a result, when used for a long time, there is a high possibility that the molded article will be broken or the chemical solution will leak. Therefore, the elongation at break calculated by the equation (1) is limited to 30% or more, and more preferably 60%. % Or more.

The above-mentioned vinyl chloride resin composition is a composition containing a vinyl chloride resin as a main component and is not particularly limited. In particular, heat resistance, alkali resistance, chemical resistance and the like of plant tubing and the like are particularly preferred. When it is used for an application requiring a chlorinated vinyl chloride resin, it is preferable to use a chlorinated vinyl chloride resin.

When a chlorinated vinyl chloride resin is used as a main component, the amount of the modifier is adjusted to 100 parts by volume.
The amount is preferably at least 4 parts by weight and less than 30 parts by weight based on parts by weight. If the amount is less than 4 parts by weight, the effect of the modifier is not sufficient, and 3
When the amount is more than 0 parts by weight, the modifier component may be deteriorated due to alkali, the compatibility with the vinyl chloride resin may be reduced, and the impact resistance may be reduced. When a vinyl chloride resin is added as necessary to the chlorinated vinyl chloride resin, the vinyl chloride resin component and the modifier component are added to 100 parts by weight of the chlorinated vinyl chloride resin. Is 1
The amount is preferably 0 parts by weight or more from the viewpoint of alkali resistance, more preferably 13 parts by weight or more. Also in this case, the modifier component is less than 30 parts by weight.

The vinyl chloride resin is (PVC resin)
Is obtained by polymerizing a vinyl chloride monomer (hereinafter referred to as VCM) alone or a mixture of VCM and another monomer copolymerizable with VCM by a known method (eg, suspension polymerization, bulk polymerization, etc.). Resin. Other monomers copolymerizable with the VCM are not particularly limited, and include, for example, alkyl vinyl esters such as vinyl acetate, α-monoolefins such as ethylene and propylene, vinylidene chloride, and styrene. These may be used alone or in combination of two or more. The porosity, surface state, particle structure, average degree of polymerization, and the like of the PVC are not particularly limited.

The chlorinated vinyl chloride resin (hereinafter referred to as CPV)
C) is a resin obtained by chlorinating a vinyl chloride resin (PVC). The method for chlorinating PVC is not particularly limited, and can be performed by various conventionally known methods. For example, it can be carried out by bringing the above PVC into a suspended state, a state of being dissolved in a solvent, or a solid state, and then contacting it with chlorine. Further, the chlorination degree of the above-mentioned CPVC is not particularly limited, and a blend of PVC and CPVC may be used.

The above-mentioned vinyl chloride resin composition contains a modifier, a stabilizer, a processing aid, a lubricant, an antioxidant, a light stabilizer,
UV absorbers, antistatic agents, pigments, fillers, plasticizers and other compounding agents that are generally used during the molding of vinyl chloride resins, are compounded as necessary within a range that does not impair the purpose of the present invention. Is also good.

The above modifier is not particularly limited as long as the object of the present invention is not impaired. For example, a silicone acrylic modifier, an acrylic modifier, a chlorinated polyethylene (CPE) modifier And a methyl methacrylate / butadiene / styrene copolymer (MBS) -based modifier. Among these modifiers, from the viewpoint of alkali resistance,
It is preferable to include at least a silicone acrylic modifier. These may be used alone or in combination of two or more.

The stabilizer is not particularly limited, and includes, for example, a heat stabilizer and a heat stabilizing aid. Examples of the heat stabilizer include, for example, organotin stabilizers such as dimethyltin mercapto, dibutyltin mercapto, dioctyltin mercapto, calcium-zinc stabilizer, barium-zinc stabilizer, barium-cadmium stabilizer, stearin And lead-based stabilizers such as lead acid. These may be used alone or in combination of two or more.

The heat stabilizing aid is not particularly restricted but includes, for example, epoxidized soybean oil, phosphate esters and the like. These may be used alone or in combination of two or more. The amounts of the stabilizers and stabilizing aids are not particularly limited as long as the objects of the present invention are not impaired.

The processing aid is not particularly restricted but includes, for example, acrylic processing aids such as alkyl acrylate / alkyl methacrylate copolymers having a weight average molecular weight of 100,000 to 2,000,000. Specifically, n-butyl acrylate / methyl methacrylate copolymer, 2-ethylhexyl acrylate / methyl methacrylate / butyl methacrylate copolymer, and the like can be given. These may be used alone or in combination of two or more. The amount of the processing aid is not particularly limited as long as the object of the present invention is not impaired.

Examples of the above 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 at the time of molding and preventing frictional heating, and specifically, for example, butyl stearate, lauryl alcohol, stearyl alcohol,
Epoxy soybean oil, glycerin monostearate, stearic acid, bisamide and the like can be mentioned. These may be used alone or in combination of two or more.

The above-mentioned external lubricant is used for the purpose of enhancing the sliding effect between the molten resin and the metal surface at the time of molding, and specifically, for example, paraffin wax, polyolefin wax, ester wax, montan Acid wax and the like. These may be used alone,
Two or more kinds may be used in combination. The amount of the lubricant is not particularly limited, and is not particularly limited as long as the object of the present invention is not impaired.

The antioxidant is not particularly limited.
For example, phenolic antioxidants and the like can be mentioned. The light stabilizer is not particularly limited, and examples thereof include hindered amines. The ultraviolet absorber is not particularly limited, and examples thereof include salicylate esters, benzophenones, benzotriazoles, and cyanoacrylates. These may be used alone or in combination of two or more.

The antistatic agent is not particularly limited.
For example, a cationic antistatic agent, a nonionic antistatic agent and the like can be mentioned.

The above-mentioned pigments are not particularly restricted but include, for example, organic pigments such as azo, phthalocyanine, sulene and dye lakes, oxides, molybdenum chromates, sulfides / selenides, ferrocyanides. And other inorganic pigments. These may be used alone or in combination of two or more.

The type and amount of the filler are not particularly limited, and examples thereof include calcium carbonate and talc. These may be used alone or in combination of two or more.

The plasticizer is not particularly restricted but includes, for example, dibutyl phthalate, di-2-ethylhexyl phthalate, di-2-ethylhexyl adipate and the like. These may be used alone or in combination of two or more.

The amounts of the above-mentioned antioxidants, light stabilizers, ultraviolet absorbers, antistatic agents, pigments, fillers and plasticizers are as follows:
There is no particular limitation as long as the properties of the vinyl chloride resin composition of the present invention are not impaired.

The molding machine used for molding the above PVC is not particularly limited, and examples thereof include a single-screw extruder, a twin-screw parallel directional extruder, a twin-screw conical extruder, and a twin-screw extruder. Is mentioned. The mold to be shaped, the resin temperature, and the molding conditions are not particularly limited.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Examples 1 to 7, Comparative Examples 1 to 5) A chlorinated vinyl chloride resin (manufactured by Tokuyama Sekisui Co., Ltd .: HA54K: degree of chlorination: 66.5 wt%) and a compounding agent were used in accordance with the compounding composition shown in Table 1. By mixing, a vinyl chloride resin composition was obtained. The obtained vinyl chloride resin composition was wound around a 200 ° C. 8-inch roll mixer (manufactured by Yasuda Seiki Co., Ltd .: 191-TM8 × 20) and kneaded for 3 minutes.
℃ press molding machine (manufactured by Toho Machinery Co.)
Press molding was performed under pressure (200 kg / cm ² ) for 2 minutes to obtain a pressed plate having a thickness of about 2 mm. A tensile test piece (JISK7113: No. 2 test piece) was cut from a press plate, and JISK
The breaking elongation (Eb) was measured at 23 ° C. according to 7113.

On the other hand, a tensile test piece obtained in the same manner was wound around a SUS pipe having an outer radius of 5 cm in a state where the length direction of the sample was bent in an arc, and both ends were fixed. At this time, the maximum surface stress generated in the tensile test piece is 18.6 to 19.
The thickness of the tensile test piece was set to 2 mm ±
Use tensile specimens adjusted in the range of 0.4 mm. The maximum surface stress is calculated by the following equation (2). Surface maximum stress (σ _max ) = (Young's modulus × thickness) / (2 × (outer radius + thickness of tensile test piece)) (2) After fixing the tensile test piece, 14 wt% heated to 50 ° C.
Was immediately immersed in an aqueous solution of KOH and left in a sealed container for 72 hours. The removed tensile test piece is washed with water, and J
The elongation at break (Ea) was measured at 23 ° C. according to ISK7113. The elongation retention at break of each sample was calculated from the following equation (1). Elongation at break retention (%) = Ea / Eb × 100
… (1)

Further, in order to evaluate the impact resistance after immersion in the chemical solution, the vinyl chloride resin composition obtained above was heated at 200 ° C.
8 inch roll mixer (manufactured by Yasuda Seiki: 191-T)
(M8 × 20), and kneaded for 3 minutes. The obtained roll sheet was press-formed by a press forming machine (manufactured by Toho Machinery Co., Ltd.) at 205 ° C. for 2 minutes with residual heat and 2 minutes under pressure (19.6 MPa). A pressed plate having a thickness of about 5 mm was obtained. A Charpy impact test piece was cut from the pressed plate, and the Charpy impact value (Ed) was measured at 23 ° C. according to JIS K7111. On the other hand, a Charpy impact test piece obtained in the same manner was
After immersion in a t% KOH aqueous solution at 50 ° C. for one month, the Charpy impact value (Ec) was measured in the same manner as described above according to JIS K7111, and the impact strength retention rate was calculated from the following formula (2) based on the impact value before and after immersion. Was calculated. Impact strength retention (%) = Ec / Ed × 100 (2)

On the other hand, the blended compositions shown in Table 1 were mixed with a Henschel mixer (Kawata: 200L super mixer), and the composition was extruded in a biaxially different direction (Sekisui Koki: SLM60). Barrel temperature using 170
~ 200 ° C, mold temperature 195 ~ 210 ° C, screw rotation speed 10 ~ 20rpm, inner diameter 50mm, wall thickness 4.
A 5 mm pipe was obtained. The resin temperature at this time is about 205
C. and the throughput was about 60-75 kg / h. A 14 wt% KOH aqueous solution heated to 50 ° C. was circulated through the obtained pipe for one month, and the acceptability of alkali resistance was determined based on the following criteria. ○ (Passed): There is no leakage or scattering of alkali, and no ESC is generated on the inner surface of the pipe. X (fail): Leakage and scattering of alkali are observed. Or ESC is generated on the inner surface of the pipe.

[0031]

[Table 1]

[0032]

As described above, the vinyl chloride resin composition of the present invention has excellent alkali resistance since it has the above constitution.
It is possible to obtain VC molded articles.

Claims (3)

[Claims] 1. A tensile test piece having a maximum surface generated stress of 18.6.
In a state of being bent into a circular arc so as to become １９19.6 MPa, the breaking elongation (Ea) after immersing in a 14% by weight KOH aqueous solution at 50 ° C. for 72 hours, and the breaking elongation before immersion (Ea)
A vinyl chloride resin composition, wherein the retention of elongation at break calculated from b) by the following formula (1) is 30% or more. Elongation at break retention (%) = Ea / Eb × 100 (1) 2. When 100 parts by weight of the chlorinated vinyl chloride-based resin contains 4 to 30 parts by weight of a modifier component, and if necessary, a vinyl chloride-based resin is added, The total of the vinyl chloride resin component and the modifier component is 10
2. The vinyl chloride resin composition according to claim 1, wherein the amount of the modifier component is at least 30 parts by weight. 3. The vinyl chloride resin composition according to claim 1, further comprising at least a silicone acrylic modifier as a modifier component.