CHLORINATED VINYL-CHLORIDE-BASED RESIN

Abstract

The present invention provides a chlorinated polyvinyl chloride resin that enables excellent continuous productivity in molding and that enables a molded article to have both processability and unevenness-preventing properties. Provided is a chlorinated polyvinyl chloride resin having an average of a ratio (A/B) of a peak intensity A observed in a range of 660 to 700 cm.sup.−1 to a peak intensity B observed in a range of 600 to 650 cm.sup.−1 of 0.50 to 2.00 in Raman imaging measurement by Raman spectroscopy.

Claims

1. A chlorinated polyvinyl chloride resin having an average of a ratio (A/B) of a peak intensity A observed in a range of 660 to 700 cm.sup.−1 to a peak intensity B observed in a range of 600 to 650 cm.sup.-1 of 0.50 to 2.00 in Raman imaging measurement by Raman spectroscopy.

2. The chlorinated polyvinyl chloride resin according to claim 1, wherein a standard deviation of the ratio (A/B) of the peak intensity A to the peak intensity B is lower than 0.100 in Raman measurement by Raman spectroscopy.

3. The chlorinated polyvinyl chloride resin according to claim 2, wherein the average of the A/B and the standard deviation of the A/B satisfy the following relation (1):
0.500≤[Average of A/B]+[Standard deviation of A/B].sup.1/2≤2.300   (1).

4. A resin composition for molding comprising the chlorinated polyvinyl chloride resin according to claim 1.

5. A molded article molded from the resin composition for molding according to claim 4.

6. A resin composition for molding comprising the chlorinated polyvinyl chloride resin according to claim 2.

7. A resin composition for molding comprising the chlorinated polyvinyl chloride resin according to claim 3.

8. A molded article molded from the resin composition for molding according to claim 6.

9. A molded article molded from the resin composition for molding according to claim 7.

Description

DESCRIPTION OF EMBODIMENTS

[0114] The present invention is hereinafter described in more detail with reference to examples; however, the present invention should not be limited to these examples.

Example 1

[0115] A glass-lined reaction vessel having an inner capacity of 300 L was charged with 130 kg of ion-exchanged water and 50 kg of a polyvinyl chloride having an average degree of polymerization of 1,000. They were stirred to disperse the polyvinyl chloride in water to prepare an aqueous suspension, and then the inside of the reaction vessel was heated to raise the temperature of the aqueous suspension to 100° C. Subsequently, the inside of the reaction vessel was depressurized to remove oxygen (oxygen content 100 ppm). Thereafter, while stirring was performed with a stirring blade such that the vortex formed at the liquid-gas interface by stirring had a vortex volume of 8.1 L, chlorine (oxygen content 50 ppm) was introduced at a partial pressure of chlorine of 0.40 MPa, thereby starting thermal chlorination. At this time, the height of the stirring blade was adjusted such that the ratio of the distance from liquid surface to the stirring blade to the height of the liquid surface (Distance from liquid surface to stirring blade/Height of liquid surface) was 0.386 (m/m). The ratio of the stirring blade diameter to the reaction vessel diameter (Stirring blade diameter/Reaction vessel diameter) was 0.60 (m/m).

[0116] Then, the chlorination temperature was kept at 100° C. and the partial pressure of chlorine was kept at 0.40 MPa. After the amount of added chlorine reached 4.2% by mass, addition of a 200 ppm hydrogen peroxide solution was started at 15 ppm/hr in terms of hydrogen peroxide relative to the polyvinyl chloride, and the average chlorine consumption rate was adjusted to 0.02 kg/PVC-kg.Math.5 min. Thereafter, when the amount of added chlorine reached 10.6% by mass, the supply of hydrogen peroxide solution and chlorine gas was terminated, whereby chlorination was terminated.

[0117] Subsequently, unreacted chlorine was removed by nitrogen gas aeration, and the obtained chlorinated polyvinyl chloride resin slurry was neutralized with sodium hydroxide, washed with water, dehydrated, and then dried. Thus, a powdery, thermally chlorinated polyvinyl chloride resin (amount of added chlorine: 10.6% by mass) was obtained.

Example 2

[0118] A glass-lined reaction vessel having an inner capacity of 300 L was charged with 130 kg of ion-exchanged water and 50 kg of a polyvinyl chloride having an average degree of polymerization of 1,000. They were stirred to disperse the polyvinyl chloride in water to prepare an aqueous suspension, and then the inside of the reaction vessel was heated to raise the temperature of the aqueous suspension to 70° C. Subsequently, the inside of the reaction vessel was depressurized to remove oxygen (oxygen content 100 ppm). Thereafter, while stirring was performed with a stirring blade such that the vortex formed at the liquid-gas interface by stirring had a vortex volume of 2.2 L, chlorine (oxygen content 50 ppm) was introduced at a partial pressure of chlorine of 0.04 MPa. The suspension was then irradiated with ultraviolet light having a wavelength of 365 nm at an irradiation intensity of 350 W using a high-pressure mercury lamp, thereby starting chlorination reaction. At this time, the height of the stirring blade was adjusted such that the ratio of the distance from liquid surface to the stirring blade to the height of the liquid surface (Distance from liquid surface to stirring blade/Height of liquid surface) was 0.133 (m/m). The ratio of the stirring blade diameter to the reaction vessel diameter (Stirring blade diameter/Reaction vessel diameter) was 0.60 (m/m).

[0119] Then, the chlorination temperature was kept at 70° C., the partial pressure of chlorine was kept at 0.04 MPa, and the average chlorine consumption rate was adjusted to 0.02 kg/PVC-kg.Math.5 min. When the amount of added chlorine reached 10.6% by mass, the ultraviolet irradiation using the high-pressure mercury lamp and the chlorine gas supply were terminated, whereby chlorination was terminated.

[0120] Subsequently, unreacted chlorine was removed by nitrogen gas aeration, and the obtained chlorinated polyvinyl chloride resin slurry was neutralized with sodium hydroxide, washed with water, dehydrated, and then dried. Thus, a powdery, photo-chlorinated polyvinyl chloride resin (amount of added chlorine: 10.6% by mass) was obtained.

Examples 3 to 17 and Comparative Examples 1 to 7

[0121] Chlorinated polyvinyl chloride resins were obtained as in Example 1 except that the volume of the reaction vessel, the average degree of polymerization of the polyvinyl chloride, the charge amount, the amount of the ion-exchanged water, the reaction temperature, the vortex volume in stirring, the Distance from liquid surface to stirring blade/Height of liquid surface, and the amount of 200 ppm hydrogen peroxide added were changed as shown in Tables 1 and 2.

(Evaluation)

[0122] The chlorinated polyvinyl chloride resins obtained in the examples and the comparative examples were evaluated as follows. Tables 1 and 2 show the results.

(1) Measurement of the Amount of Added Chlorine

[0123] The amount of added chlorine was measured for each of the obtained chlorinated polyvinyl chloride resins in conformity with JIS K 7229.

(2) Molecular Structure Analysis

[0124] The molecular structure of each of the obtained chlorinated polyvinyl chloride resins was analyzed in conformity with the NMR measurement method described in R. A. Komoroski, R. G. Parker, J. P. Shocker, Macromolecules, 1985, 18, 1257-1265 so as to determine the amount of the structural units (a), (b), and (c).

[0125] The NMR measurement conditions were as follows.

[0126] Apparatus: FT-NMRJEOLJNM-AL-300

[0127] Measured nuclei: 13C (proton complete decoupling)

[0128] Pulse width: 90°

[0129] PD: 2.4 sec

[0130] Solvent: o-dichlorobenzene:deuterated benzene (C5D5)=3:1

[0131] Sample concentration: about 20%

[0132] Temperature: 110° C.

[0133] Reference material: central signal for benzene set to 128 ppm

[0134] Number of scans: 20,000

(3) Raman Spectroscopic Analysis

(3-1) Raman Imaging Measurement

[0135] Each of the obtained powdery chlorinated polyvinyl chloride resins was molded into a sheet shape using a vacuum press (produced by Meiki Co., Ltd., MHPC-VF) to prepare a resin sheet having a thickness of 0.5 mm. Here, for pressurization, the vacuum press was set at 180° C. The powdery chlorinated polyvinyl chloride resin was set in the vacuum press and the air was evacuated over one minute. At this time, evacuation needs to be performed from atmospheric pressure to 10 hPa within 30 seconds, because exposure to oxygen during heating causes oxidation or dehydrochlorination. Molding was then performed at a pressure of 3 MPa, a pressure-increase time of 30 seconds, and a dwell time of 1 minute, and the pressure was rapidly decreased to atmospheric pressure, followed by cooling. Thus, the resin sheet was prepared.

[0136] The obtained resin sheet was then cut using a microtome. The obtained cross section was subjected to Raman spectroscopic measurement using a micro-Raman spectrometer (produced by Nanophoton Corporation, RAMANtouch).

[0137] The Raman spectroscopic measurement was performed under the conditions of an objective lens magnification of 20× and an excitation wavelength of 532 nm in a region of 400 μm×100 μm at 1-μm intervals in the×direction and 2-μm intervals in the y direction. Raman spectra of 20,000 points of the cross section of the resin sheet were thus obtained.

[0138] The obtained Raman spectra were baseline-corrected by linear approximation using a baseline from 400 cm.sup.−1 to 850 cm.sup.−1, and the peak intensity B observed in the range of 600 to 650 cm.sup.−1 and the peak intensity A observed in the range of 660 to 700 cm.sup.−1 were measured. Thereafter, the ratio (A/B) of the peak intensity A to the peak intensity B was calculated, and the average of the A/B was calculated.

(3-2) Raman Spectroscopy

[0139] Raman spectra of the obtained chlorinated polyvinyl chloride resins were measured using a micro-Raman spectrometer (produced by Thermo Fisher Scientific K.K., Almega XR). Here, the Raman spectra were measured for randomly collected 50 particles of each of the obtained powdery chlorinated polyvinyl chloride resins using a laser with a wavelength of 532 nm at an exposure time of 1 second and a scan number of 32. Raman spectroscopic analysis of particles themselves allows for obtaining the peak intensities of the particle surfaces. The wavenumbers of the Raman shifts were calibrated with the metal silicon peak at 520.5 cm.sup.−1.

[0140] The obtained Raman spectra were baseline-corrected by linear approximation using a baseline from 515 cm.sup.−1 to 950 cm.sup.−1. The peak intensity B observed in the range of 600 to 650 cm.sup.−1 (mainly 641 cm.sup.−1) and the peak intensity A observed in the range of 660 to 700 cm.sup.−1 (mainly 697 cm.sup.−1) were measured. The ratio (A/B) of the peak intensity A to the peak intensity B was then calculated, and the average of the A/B of the 50 particles and the standard deviation of the A/B were calculated.

(4) Developed Interfacial Area Ratio (Sdr)

[0141] (Production of chlorinated polyvinyl chloride resin composition)

[0142] An amount of 5.5 parts by mass of an impact resistance modifier was added to 100 parts by mass of each of the obtained chlorinated polyvinyl chloride resins. Then, 1.5 parts by mass of a thermal stabilizer was added and mixed. The impact resistance modifier used was Kane Ace B-564 (produced by Kaneka Corporation, methyl methacrylate-butadiene-styrene copolymer). The thermal stabilizer used was TVS*1380 (produced by Nitto Kasei Co., Ltd., organotin stabilizer).

[0143] Further, 2.0 parts by mass of a polyethylene lubricant (produced by Mitsui Chemicals, Inc., Hiwax 220MP) and 0.3 parts by mass of a fatty acid ester lubricant (produced by Emery Oleochemicals Japan Ltd., LOXIOL G-32) were added. They were uniformly mixed in a super mixer, whereby a chlorinated polyvinyl chloride resin composition was obtained.

(Production of Extrusion-Molded Article)

[0144] The obtained chlorinated polyvinyl chloride resin composition was fed into a twin-screw counter-rotating conical extruder with a diameter of 50 mm (produced by Osada Seisakusho, SLM-50) to prepare a sheet-shaped molded article with a thickness of 2 mm and a width of 80 mm at a resin temperature of 207° C., a back pressure of 150 kg/cm.sup.2, and an extrusion amount of 40 kg/hr.

(Sdr Measurement)

[0145] The Sdr value of a surface of the obtained molded article was measured using a 3D measurement system (produced by Keyence Corporation, VR-3100). Each Sdr value shown in Tables 1 and 2 is the average of five measurement regions.

[0146] Sdr is a ratio representing the degree of increase in the surface area of the measured region compared to the area of the measured region. A completely level surface has an Sdr of 0. A molded article having a low Sdr has excellent smoothness. Using such a molded article as, for example, a pipe-shaped molded article for plumbing or the like can reduce noise when water is running.

(5) Scorch Marks (Discoloration) of Molded Article

[0147] The surface state of the obtained molded article was visually examined and evaluated in accordance with the following criteria.

◯ (Good): No scorch mark (discoloration) was observed.
x (Poor): Scorch mark(s) (discoloration) was/were observed.

(6) Surface Shape (Unevenness)

[0148] The surface shape of the molded article was examined visually and by touch, and evaluated in accordance with the following criteria.

◯ (Good): Neither the visual examination nor the touch examination found surface irregularities.
Δ (Fair): The visual examination found no surface irregularities but the touch examination found surface irregularities.
x (Poor) The visual examination found surface irregularities.

(7) Continuous Productivity

[0149] The obtained chlorinated polyvinyl chloride resin composition was fed into a twin-screw counter-rotating conical extruder with a diameter of 50 mm (produced by Osada Seisakusho, “SLM-50”) to prepare sheet-shaped molded articles with a thickness of 2 mm and a width of 80 mm at a resin temperature of 207° C., a back pressure of 150 kg/cm.sup.2, and an extrusion amount of 40 kg/hr. The time from the start of the molding to the occurrence of a scorch mark (discoloration) in the obtained molded article was measured, and the continuous productivity was evaluated.

[0150] A longer time before the occurrence of a scorch mark (discoloration) in the molded article indicates that the chlorinated polyvinyl chloride resin is less likely to contaminate the die surface and enables excellent continuous productivity when products are continuously produced by repeating similar operations for a long time.

(8) Color Tone

[0151] An amount of 100 parts by mass of each of the obtained chlorinated polyvinyl chloride resins was mixed with 1.5 parts by mass of a thermal stabilizer, 0.5 parts by mass of a lubricant, and 10 parts by mass of an impact resistance modifier. The thermal stabilizer used was TVS*1380 (produced by Nitto Kasei Co., Ltd., organotin stabilizer). The lubricant used included 0.435 parts by mass of a polyethylene lubricant (produced by Mitsui Chemicals, Inc., Hiwax 220MP) and 0.065 parts by mass of a fatty acid ester lubricant (produced by Emery Oleochemicals Japan Ltd., LOXIOL G-32). The impact resistance modifier used was Kane Ace B-564 (produced by Kaneka Corporation, methyl methacrylate-butadiene-styrene copolymer).

[0152] The obtained mixture was supplied to two 8-inch rolls, kneaded at 200° C. for three minutes, and formed into sheets each having a thickness of 1.0 mm. The obtained sheets were stacked, pre-heated using a press at 185° C. for three minutes, and pressurized for seven minutes, whereby a press plate having a thickness of 2 mm was obtained. The obtained press plate was mechanically processed to cut out a test specimen (15 mm×15 mm×2 mm) therefrom. The YI value of this test specimen was measured using a colorimeter (NR-3000, produced by Nippon Denshoku Industries Co., Ltd.).

TABLE-US-00001 TABLE 1 Examples 1 2 3 4 5 6 7 8 9 10 11 12 Production Reaction vessel Volume L method Raw material Average degree of polymerization PVC Charge amount kg Water Ion-exchanged water kg Chlorination Reaction temperature ° C. conditions Reaction pressure Mpa PVC + water kg Vortex volume in stirring L (Distance from liquid surface to stirring m/m blade)/Height of liquid surface Vortex volume/(PVC +water) L/kg (PVC + water)/ kg/L Reaction vessel volume Average chlorine consumption rate kg/pvc − kg .Math. 5 min 200 ppm hydrogen peroxide ppm/hr UV wavelength nm Chlorinated Amount of added chlorine mass % polyvinyl Structure Structural unit (a) mol % chloride —CH.sub.2-CHCl— resin Structural unit (b) mol % —CH.sub.2-CCl.sub.2- Structural unit (c) mol % —CHCl—CHCl— Raman Peak intensity A/B Average spectroscopic Standard analysis deviation (Peak average of NB) + (Standard deviation).sup.1/2 Molded Sdr article Scorch mark (discoloration) Surface shape (unevenness) Continuous productivity (hr) Color tone indicates data missing or illegible when filed

TABLE-US-00002 TABLE 2 Examples Comparative Examples 13 14 15 16 17 1 2 3 4 5 6 7 Production Reaction vessel Volume L 300 200 600 300 300 300 300 300 300 300 300 300 method Raw material Average degree of polymerization 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 PVC Charge amount kg 50 30 60 41.7 57.5 50 50 66.7 37.5 50 37.5 62.5 Water Ion-exchanged water kg 130 105 270 108.3 149.5 130 130 173.3 97.5 130 97.5 162.5 Chlorination Reaction temperature ° C. 100 100 100 100 100 140 80 100 100 100 100 100 conditions Reaction pressure Mpa 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 PVC + water kg 180 135 330 150 207 180 180 240 135 180 135 225 Vortex volume in stirring L 25.2 11.1 25.7 13.4 19.0 32.5 1.2 37.4 0.8 27.0 12.2 27.0 (Distance from liquid surface to m/m 0.673 0.442 0.440 0.446 0.449 0.960 0.057 0.886 0.040 0.795 0.447 0.522 stirring blade)/Height of liquid surface Vortex volume/(PVC +water) L/kg 0.140 0.082 0.078 0.089 0.092 0.181 0.007 0.156 0.006 0.150 0.090 0.120 (PVC + water)/ kg/L 0.600 0.675 0.550 0.500 0.690 0.600 0.600 0.800 0.450 0.600 0.450 0.750 Reaction vessel volume Average chlorine consumption kg/pvc − 0.042 0.056 0.037 0.025 0.035 0.05 0.01 0.07 0.02 0.056 0.062 0.03 rate kg .Math. 5 min 200 ppm hydrogen peroxide ppm/hr 200 80 45 10 30 50 50 100 120 50 20 45 UV wavelength nm — — — — — — — — — — — — Chlorinated Amount of added chlorine mass % 10.4 10.9 10.2 8.7 8.9 15.6 2.3 15.6 3.2 15.6 15.9 15.5 polyvinyl Structure Structural unit (a) mol % 37.6 35.2 39.2 48.3 47.2 5.8 87.3 5.8 82 5.8 4.1 6.7 chloride —CH.sub.2-CHCl— resin Structural unit (b) mol % 24.7 25.9 24.1 21.3 22.8 38.7 5.9 52.3 9.2 45.2 55.5 46.2 —CH.sub.2-CCl.sub.2- Structural unit (c) mol % 37.7 39.0 36.7 30.4 30.0 55.5 6.8 41.9 8.8 49.0 40.4 47.1 —CHCl—CHCl— Raman Peak intensity A/B Average 1.401 1.430 1.390 1.303 1.314 2.050 0.390 2.050 0.425 2.040 2.058 2.046 spectroscopic Standard 0.004 0.008 0.003 0.002 0.002 0.072 0.011 0.103 0.005 0.103 0.113 0.103 analysis deviation (Peak average of NB) + (Standard 1.465 1.517 1.446 1.350 1.355 2.318 0.495 2.371 0.496 2.361 2.394 2.367 deviation).sup.1/2 Molded Sdr 0.0020 0.0017 0.0010 0.0002 0.0002 0.0130 0.0001 0.0123 0.0009 0.0115 0.0117 0.012 article Scorch mark (discoloration) ∘ ∘ ∘ ∘ ∘ x x x x x x x Surface shape (unevenness) ∘ ∘ ∘ ∘ ∘ x ∘ x ∘ x x x Continuous productivity (hr) 8.9 6.5 6.8 3.9 6.3 2.6 0.6 0.2 0.5 1.9 0.9 2.5 Color tone 75.9 75.2 76.2 76.2 76.4 79.8 49.4 88.0 58.1 81.0 80.5 78.5

INDUSTRIAL APPLICABILITY

[0153] The present invention can provide a chlorinated polyvinyl chloride resin that enables excellent continuous productivity in molding and that enables a molded article to have both processability and unevenness-preventing properties.