JP2001098126A - Heat-resistant vinyl resin composition and molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-resistant vinyl chloride resin composition having excellent heat resistance and high impact strength and moldings therefrom. SOLUTION: The objective heat-resistant vinyl resin composition mainly comprises a chlorinated vinyl chloride resin and only organic stabilizer as a stabilizer. A molded product from the vinyl chloride resin composition gives molded products having the Charpy impact value of >=50 kg.cm/cm2 at 23 deg.C according to JIS K 7111 and the breaking stress of >=5.0 MPa in 1,000 hours breaking time at 90 deg.C in the long-term inner pressure creep test according to ASTM D 2837.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a heat-resistant vinyl chloride resin composition and a molded article.

[0002]

2. Description of the Related Art Vinyl chloride resins (hereinafter, also referred to as PVC) are particles having fine pores (grain particles) because they are usually produced by water suspension polymerization, and the molded product has mechanical strength and weather resistance. It is used in many applications such as water supply pipes because it has excellent properties and chemical resistance and is inexpensive compared to other plastic materials. However, PVC has a low heat distortion temperature and its usable upper limit temperature is around 60 to 70 ° C., so that it has been difficult to use PVC for hot water supply pipes through which hot water flows.

Therefore, in order to improve the durability of PVC at high temperatures, a chlorinated vinyl chloride resin (hereinafter also referred to as CPVC) has been developed in which PVC is chlorinated to improve heat resistance. As a result, a PVC-based resin molded article having easy workability and easy adhesion, which are inherent properties of PVC, and also having heat resistance has been produced.

[0004] However, although the heat resistance of the molded product of CPVC is improved as the degree of chlorination is increased, the impact resistance is reduced, cracks occur during transportation and use, and the resin temperature does not increase during molding. Therefore, there is a problem that physical properties are hardly sufficiently developed.

[0005] Regarding the problem of impact resistance, methyl methacrylate / butadiene / styrene copolymer (M
It is possible to solve the problem by adding BS) or an acrylic modifier. In order to sufficiently exhibit the physical properties of the molded article, generally, a method of increasing the molding resin temperature or the mold temperature or increasing the residence time in the mold is used. In order to express sufficient physical properties to molded products, the molding temperature must be increased considerably,
The residence time in the mold needs to be considerably long. Therefore, the resin is likely to be decomposed due to the heat history, which may cause a problem in long-run property (continuous production).

[0006] In order to solve such problems, it is necessary to improve the thermal stability of the heat-resistant vinyl chloride resin composition.
In order to improve the thermal stability of the chlorinated vinyl chloride resin which is the main component of the composition, chlorination temperature, pressure during chlorination,
Various studies have been made on the amount of hydrogen peroxide added, the timing of addition, and the like.However, optimizing the conditions during chlorination alone cannot ensure sufficient thermal stability, resulting in the above problems. Was difficult to solve.

The long run property can be improved by increasing the amount of the stabilizer to improve the thermal stability. However, a liquid stabilizer such as a tin-based stabilizer or an organic-based material which melts in the operating temperature range is used. When a stabilizer is used, on the other hand, there is a problem in that the heat resistance is reduced and the long-term creep performance at high temperatures is inferior.

[0008] In order to solve the above-mentioned problem, the use of an inorganic stabilizer as described in Taiseisha's “Revised New Edition, Plastics Compounding Agent-Basics and Applications”, page 48,
Thermal stability can be imparted without lowering heat resistance. However, when these inorganic stabilizers are used, there is a problem that physical properties such as impact resistance are significantly reduced. Further, in such a case, although the impact resistance is improved by adding a large amount of the impact resistance modifier, there is a problem that the durability at a high temperature is significantly reduced.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and provides a heat-resistant vinyl chloride resin composition and a molded article having excellent heat resistance and impact resistance. The task is to

[0010]

The heat-resistant vinyl chloride resin composition of the present invention contains a chlorinated vinyl chloride resin as a main component and contains only an organic stabilizer as a stabilizer. A molded article obtained from the composition has a Charpy impact value at 23 ° C. according to JIS K 7111 of 50 kg · cm / cm ² or more, and a long-term internal pressure at 90 ° C. according to ASTM D2837. In the creep test, a breaking stress at a breaking time of 1000 hours is not less than 5.0 MPa.

A molded article obtained from the above heat-resistant vinyl chloride resin composition has a temperature of 23 ° C. in accordance with JIS K 7111.
Is required to be 50 kg · cm / cm ² or more. The above Charpy impact value is 50k
If it is less than g · cm / cm ² , the molded article may be broken by impact, and when used in a pipe, a high-temperature fluid may flow out or may be broken during transportation or processing.

A molded article obtained from the heat-resistant vinyl chloride resin composition has a breaking time of 1 in a long-term internal pressure creep test at 90 ° C. in accordance with ASTM D2837.
It is necessary that the breaking stress in 000 hours is 5.0 MPa or more. If the above-mentioned fracture stress is less than 5.0 MPa, it is difficult to use it in an application of flowing hot water, or it can be used for a long time without breaking when used in a high-temperature atmosphere or when using a high-temperature fluid. Chip.

The heat-resistant vinyl chloride resin composition contains a chlorinated vinyl chloride resin (CPVC) as a main component, and the CPVC can be obtained by chlorinating the vinyl chloride resin (PVC). . In the present invention, in order to improve the heat resistance of CPVC, PVC before chlorination is used.
Focusing on the resin structure of VC, it has become possible to obtain CPVC having excellent thermal stability.

In order to obtain a heat-resistant vinyl chloride resin composition having the above-mentioned properties with respect to the surface state and particle structure of PVC before chlorination of CPVC, for example, a BET specific surface area value of 2.0 to 12.0 m ² / g, electron spectrochemical (ES
CA) In the particle surface analysis by analysis, the peak ratio of carbon atoms and chlorine atoms in the 1s bond energy value (eV) exceeds 0.6, and the pressure ranges from 0 to 2000 kg / cm ² by the mercury intrusion method. In the measured pore volume distribution, the void volume in the range of 0.001 to 0.1 μm is preferably 2 to 15% by volume of the total void volume.

The above PVC has a BET specific surface area of 2.0 m.
If it is less than ² / g, fine pores of 0.1 μm or less are reduced inside the PVC particles, so that chlorination may not be uniform and thermal stability may not be improved. Further, the gelation is slow, which is not preferable in the molding process. Meanwhile, BET
If the specific surface area value exceeds 12.0 m ² / g, the thermal stability of the PVC particles themselves before chlorination decreases, so that the resulting C
The workability of PVC may be deteriorated.

If the peak ratio of carbon atoms and chlorine atoms of the above PVC at 1 s bond energy value (eV) is 0.6 or less, it is considered that an additive such as a dispersant is adsorbed on the surface of the PVC particles. Not only does the chlorination rate in the process become slow, but also a problem arises in the formability of the resulting CPVC, and the thermal stability becomes poor. More preferably, the peak ratio exceeds 0.7.

The abundance ratio of chlorine atoms to carbon atoms in the PVC is chlorine atom: carbon atom = 1: 2 (when the terminal structure and branching are not taken into account), and the 1s binding energy value (eV ) Has a value of 0 to 1 (chlorine atom peak × 2 / carbon atom peak). When the peak ratio is 0, the surface of the PVC particles is other than PVC, and
When the peak ratio is 1, it means that the surface of the PVC particles is completely covered with only the vinyl chloride component.

In the above measured pore volume distribution of PVC,
When the void volume in the range of 0.001 to 0.1 μm is less than 2% by volume of the total void volume, the ratio of the micropores inside the particles is reduced, so that the gelling property at the time of molding may be inferior, If it exceeds 15% by volume, the diffusion of chlorine at the time of chlorination will not be performed in a well-balanced manner, and the chlorine content distribution in the particles will be too large, resulting in poor thermal stability. More preferably, the void volume in the range of 0.001 to 0.1 μm is 2 to 15% by volume of the total void volume.

The above PVC is a vinyl chloride monomer (hereinafter, referred to as a vinyl chloride monomer).
It is a resin obtained by polymerizing VCM alone or a mixture of VCM and another monomer copolymerizable with VCM by a known method (for example, suspension polymerization, bulk polymerization and the like). V above
Other monomers copolymerizable with CM are not particularly limited, for example, alkyl vinyl esters such as vinyl acetate, ethylene, α-monoolefins such as propylene,
Examples include vinylidene chloride and styrene. These may be used alone or in combination of two or more.

The average degree of polymerization of the PVC is not particularly limited, but if it is too high, the smoothness of the heat-resistant vinyl chloride resin molded article may be impaired, and if it is too low, the long-term creep properties at high temperatures may be poor. Therefore, 700 to 1500 is preferable. More preferably, it is 900 to 1100. The average degree of polymerization can be measured by a method according to JIS K6721.

The method for chlorinating PVC is not particularly limited, and can be carried out by various conventionally known methods.
For example, it can be carried out by bringing the above PVC into a suspended state, a state dissolved in a solvent, or a solid state, and then contacting it with chlorine.

The degree of chlorination of CPVC obtained by the above chlorination reaction is not particularly limited. However, if it is too high, problems such as smoothness and unevenness of the heat-resistant vinyl chloride resin molded article, or a decrease in impact resistance occur. 60. The moldability when molding the heat-resistant vinyl chloride resin molded article may be inferior, and when it is too low, the long-term creep property at high temperature may be inferior.
0 to 72.0% by weight is preferred. More preferably, 65.
0 to 68.0% by weight.

The porosity and BET specific surface area of the above-mentioned CPVC are not particularly limited, but the porosity is preferably 30 to 40% by volume, and the BET specific surface area is 2 to 2 from the viewpoint that the gelling property can be imparted to CPVC. 12 m ² / g is preferred.

The heat-resistant vinyl chloride resin composition of the present invention contains the above-mentioned CPVC as a main component and contains only an organic stabilizer as a stabilizer. When an inorganic stabilizer is used as the stabilizer, Since it does not completely melt during molding, it becomes the starting point of the destruction of the molded article, and the impact resistance at room temperature is significantly reduced.

The organic stabilizer is not particularly limited, and includes, for example, a heat stabilizer, a heat stabilizing aid and the like.
Examples of the heat stabilizer include organic tin-based stabilizers such as dimethyltin mercapto, dibutyltin mercapto, and dioctyltin mercapto, and lead-based stabilizers such as lead stearate. These may be used alone or in combination of two or more. Among these heat stabilizers, when the heat-resistant vinyl chloride resin molded article of the present invention is used as a hot water supply pipe, it is not preferable to use a toxic lead-based stabilizer or the like, and it is preferable to use a tin-based stabilizer. Is preferred.

The heat stabilizing aid is not particularly restricted but includes, for example, epoxidized soybean oil and phosphate esters. These may be used alone or in combination of two or more. The amounts of the stabilizer and the stabilization aid are not particularly limited.

When a molded article is produced by molding the heat-resistant vinyl chloride resin composition, in addition to the organic stabilizer,
Compounding agents, such as modifiers, processing aids, lubricants, antioxidants, light stabilizers, ultraviolet absorbers, antistatic agents, pigments, fillers, and plasticizers, which are generally used when molding vinyl chloride resins. It may be blended with CPVC as long as the object of the present invention is not impaired.

The modifier is not particularly restricted but includes, for example, silicone modifier, methyl methacrylate / butadiene / styrene copolymer (MBS) modifier, chlorinated polyethylene (CPE) modifier, Acrylic modifiers are exemplified. These may be used alone or in combination of two or more. The amount of the modifier added is not particularly limited as long as the properties of the heat-resistant vinyl chloride resin molded article 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. However, if the amount is too large, the cost increases. If the amount is too small, it is difficult to stably maintain the smoothness and unevenness of the heat-resistant vinyl chloride resin molded article. 0.1-5.
0 parts by weight is preferable, and 0.3 to 2.5 parts by weight is more preferable.

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 increasing the sliding effect between the molten resin and the metal surface during the molding process. 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 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 restricted but includes, for example, salicylic acid 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 filler is not particularly restricted but includes, for example, calcium carbonate, talc and the like. 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 heat-resistant vinyl chloride resin molded article of the present invention are not impaired.

The molding machine used for molding the heat-resistant vinyl chloride resin composition of the present invention is not particularly limited. For example, a single-screw extruder, a twin-screw parallel directional extruder, a twin-screw conical extruder And a twin-screw co-extruder.

When molding using the above molding machine, the mold to be formed, the resin temperature, the molding conditions and the like are not particularly limited.

The higher the resin temperature, the higher the temperature at which decomposition, long-run properties, physical properties and the like are not problematic.
Although the smoothness of the molded article is good, when the heat-resistant temperature of the molded article is set to t ° C. from the viewpoint of thermal stability and long run property, [19
5+ (t−120) / 2] ° C. to [210+ (t−12)
0)] ° C is preferred.

Although the temperature at the tip of the mold is not particularly limited, if the heat-resistant temperature of the molded body is t ° C. from the viewpoint of thermal stability and long running property, [190+ (t−120) / 2] ° C.
~ [220+ (t-120)] ° C.

[0044]

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.

(Example 1) [Preparation of PVC] Internal volume 10
After 50 kg of deionized water is put into a 0-liter polymerization vessel (pressure-resistant autoclave), the amount becomes 1200 ppm of partially saponified polyvinyl acetate having an average degree of saponification of 88 mol% and a degree of polymerization of 1000 with respect to the vinyl chloride monomer. Was added as a suspending and dispersing agent, and further, an amount of 550 ppm of t-butyl peroxyneodecanoate was added. Next, after degassing the inside of the polymerization vessel to 45 mmHg, the vinyl chloride monomer 3
3 kg was charged and stirring was started. The temperature of the polymerization vessel was raised to 56 ° C. to start polymerization, and this temperature was maintained until the polymerization reaction was completed. The reaction was terminated when the polymerization conversion reached 50%,
After recovering the unreacted monomer in the polymerization vessel, the polymer was taken out of the system in a slurry state, and dehydrated and dried to obtain PVC. The polymerization degree of the obtained PVC was 1,050.

[Preparation of CPVC] The obtained hydrous PV was placed in a pressure-resistant reaction vessel made of glass lining having an internal volume of 300 liters.
200 kg of C (40 kg of vinyl chloride resin and 1 aqueous medium)
60 kg) and stirred to disperse the PVC in the water. Thereafter, the inside of the reactor was heated to 110
C. Next, nitrogen gas is blown into the reaction tank,
After replacing the inside of the tank with nitrogen gas, chlorine gas was blown into the reaction tank to chlorinate PVC. The chlorination reaction is continued while monitoring the progress of the chlorination reaction by measuring the concentration of hydrochloric acid in the reaction tank. When the chlorine content of the generated CPVC reaches 66.4% by weight, the supply of chlorine gas is stopped. Then, the chlorination reaction was completed. Furthermore, nitrogen gas was blown into the reaction tank to remove unreacted chlorine. The obtained resin was neutralized with sodium hydroxide, washed with water, dehydrated and dried to obtain a powdery CPVC. The chlorine content of the obtained CPVC was 66.5% by weight.

[Blending] Various blending agents shown in Table 1 were added to 100 parts by weight of the above-mentioned CPVC, mixed while heating from room temperature to 130 ° C. with a Henschel mixer, and then cooled to 45 ° C. with a cooling mixer.

[Molding] Using the above compounded powder, molding was performed under the following extrusion conditions. Extruder: SLM50 (biaxially different direction conical extruder) manufactured by Nagata Seisakusho Co., Ltd. Mold: Pipe mold, outlet outer radius 11.66 mm, outlet inner radius 9.4 mm, L / D = 60 / 2.3. (M
m), chromium plating on the resin flow surface, three bridges Extrusion amount: 25 kg / h Resin temperature: 200 ° C. (temperature at the mold inlet) Rotation speed: 20 to 25 rpm Mold temperature: D1 190 ° C., D2 205 ° C. D3 2
10 ℃ (parallel tip)

(Example 2) [Preparation of PVC] The same procedure as in Example 1 was carried out. [Preparation of CPVC] The obtained CPVC had a chlorine content of 6%.
The procedure was performed in the same manner as in Example 1 except that the content was 7.0% by weight. [Blending] The same procedure as in Example 1 was carried out using the various blending agents shown in Table 1. [Molding] Using the same extruder and mold as in Example 1, molding was performed under the same extrusion conditions.

(Example 3) [Preparation of PVC] The same procedure as in Example 1 was carried out. [Preparation of CPVC] The obtained CPVC had a chlorine content of 6%.
The procedure was performed in the same manner as in Example 1 except that the content was 6.0% by weight. [Blending] The same procedure as in Example 1 was carried out using the various blending agents shown in Table 1. [Molding] Using the same extruder and mold as in Example 1, molding was performed under the same extrusion conditions.

(Comparative Example 1) [Preparation of PVC] The same procedure as in Example 1 was carried out. [Preparation of CPVC] The procedure of Example 1 was repeated. [Blending] The same procedure as in Example 1 was carried out using the various blending agents shown in Table 1. [Molding] Using the same extruder and mold as in Example 1, molding was performed under the same extrusion conditions.

(Comparative Example 2) [Preparation of PVC] The same procedure as in Example 1 was carried out. [Preparation of CPVC] The obtained CPVC had a chlorine content of 6%.
The procedure was performed in the same manner as in Example 1 except that the content was 7.0% by weight. [Blending] The same procedure as in Example 1 was carried out using the various blending agents shown in Table 1. [Molding] Using the same extruder and mold as in Example 1, molding was performed under the same extrusion conditions.

[Evaluation Method of Heat-Resistant Vinyl Chloride-Based Resin Molded Articles] The Charpy impact value of the heat-resistant vinyl chloride-based resin molded articles obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was determined.
The breaking stress at a breaking time of 1000 hours was evaluated by the following evaluation method. The results are shown in Table 1.

(1) Charpy impact value Measurement was carried out at a measurement temperature of 23 ° C. in accordance with JIS K 7111.

(2) Long-term internal pressure creep test Measured with hot water at 90 ° C. in accordance with ASTM D 2837, and the breaking stress at breaking time of 1000 hours was evaluated.

[0056]

[Table 1]

As shown in Table 1, Examples 1, 2 and 3
The molded article obtained from the heat-resistant vinyl chloride resin composition of
Since the breaking stress at a breaking time of 1000 hours is 5.0 MPa or more, high reliability when used for a long time at a high temperature is high, and the Charpy impact value is 50 kg · cm / cm ² or more. Demonstrate.

As shown in Table 1, the molded article obtained from the heat-resistant vinyl chloride resin composition of Comparative Example 1 had a low impact resistance because it used an inorganic stabilizer, and was used or transferred during use. There is a high risk of destruction during.

As shown in Table 1, a molded article obtained from the heat-resistant vinyl chloride resin composition of Comparative Example 2 was prepared for the purpose of compensating for a decrease in impact resistance due to the use of an inorganic stabilizer.
Since a large amount of the modifier was added, the breaking stress at a breaking time of 1000 hours was 5.0 MPa or less, and the reliability when used for a long time at a high temperature was low.

[0060]

As described above, the heat-resistant vinyl chloride resin composition of the present invention has the above-mentioned constitution, so that the obtained molded article has excellent impact resistance and high long-term creep at high temperatures.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F071 AA24 AA79 AC13 AC15 AE05 AF02 AF17Y AF23Y AF37 AF58 BA01 BB06 BC03 4J002 BD181 EG046 EZ076 FD010 FD020 FD036 FD040 FD050 FD070 FD090 FD100 FD170

Claims (2)

[Claims] 1. A chlorinated vinyl chloride resin as a main component,
A heat-resistant vinyl chloride-based resin composition containing only an organic stabilizer as a stabilizer, and a molded article obtained from the composition has a Charpy impact value at 23 ° C. in accordance with JIS K 7111 of 50 kg · cm / cm. cm ² or more and AS
A heat-resistant vinyl chloride-based resin composition, which has a breaking stress of 5.0 MPa or more at a breaking time of 1000 hours in a long-term internal pressure creep test at 90 ° C. in accordance with TMD2837. 2. A heat-resistant vinyl chloride-based resin molded article, which is molded from the heat-resistant vinyl chloride-based resin composition according to claim 1.