Disclosure of Invention
The invention provides a synergistic heat stabilizer and application thereof in improving thermal stability of PVC (polyvinyl chloride) in order to solve the problems of high price and poor heat resistance of methyl tin mercaptide at present. The invention takes organic tin, cerium metal soap and butyl titanate as active components, and the crosslinking effect between butyl titanate coupling agent and tin, cerium metal and PVC is utilized to reinforce after microwave radiation, thus being capable of being used for preparing novel PVC composite film material with excellent heat stabilization effect and potential microwave radiation resistance.
Tetrabutyl titanate is a colorless to pale yellow oily liquid, relative density: 0.966, freezing point: -55 ℃, flash point: 76.7 ℃, boiling point: 310-314 ℃, is an organic titanium compound used as a catalyst for polycondensation and crosslinking reactions, is mainly used for esterification and transesterification reactions, such as synthetic polyester polyol, and can also be used as a tackifier of metal-plastic, a modifier of high-strength polyester paint, a crosslinking agent and the like.
The invention relates to a synergistic heat stabilizer, which takes organic tin as a main heat stabilizer and butyl titanate modified cerium metal soap complex as an auxiliary stabilizer. The butyl titanate as the coupling agent has obvious synergistic stabilizing effect on organic tin and cerium metal soap, and can effectively improve the thermal stability of PVC.
The invention discloses a synergistic heat stabilizer, which comprises the following components in parts by weight:
1.0-5.0 parts of butyl titanate, 1.0-5.0 parts of cerium metal soap and 0.1-1.0 part of organic tin heat stabilizer.
More preferably: 1.0-5.0 parts of butyl titanate, 1.0-5.0 parts of cerium metal soap and 0.5 part of organic tin heat stabilizer.
The cerium metal soap is cerium stearate.
The organotin includes methyltin mercaptide, octyltin mercaptide, butyltin mercaptide, dioctyltin laurate, and the like.
The preparation method of the synergistic heat stabilizer comprises the following steps:
by adopting a microwave radiation technology, 50 parts by mass of DOTP, 1.0-5.0 parts by mass of butyl titanate, 1.0-5.0 parts by mass of cerium metal soap and 0.1-1.0 part by mass of organic tin heat stabilizer are mixed and dissolved, then the mixture is placed in a glass container, microwave (with power output of 17%) is started in a microwave oven to radiate and mix for 15min, and a uniform precursor is obtained, wherein the power of the microwave oven is 700w.
DOTP added in the preparation process is dioctyl terephthalate which is a plasticizer of the PVC material, DOTP is used as a solvent when being added in advance in the preparation process of the synergistic heat stabilizer, unnecessary addition of other solvents is avoided, and the plasticizer is not required to be added in the subsequent preparation process of the PVC material.
The application of the synergistic heat stabilizer is to add the synergistic heat stabilizer into a PVC base material so as to improve the heat stability of the PVC material. Wherein the proportion of each component is as follows: 100 parts of PVC resin, 1.0-5.0 parts of butyl titanate, 1.0-5.0 parts of cerium metal soap and 0.1-1.0 part of organic tin heat stabilizer.
The preferable mixture ratio is as follows: 100 parts of PVC resin, 1.0-5.0 parts of butyl titanate, 1.0-5.0 parts of cerium metal soap and 0.5 part of organic tin heat stabilizer.
The application of the synergistic heat stabilizer is specifically that a synergistic heat stabilizer precursor is mixed with a PVC base material, the mixture is stirred at a high speed to obtain a premix, then the premix is placed in an internal mixer for internal mixing, the melt temperature is 170-175 ℃, the screw rotation speed is 40r/min, the internal mixing time is 2-3min, after the torque is rapidly increased and then decreased and is kept unchanged, the mixed material is taken out, a flat vulcanizing machine is adopted for tabletting at 100 ℃ for 40 seconds, and then the PVC sheet with the thickness of 1mm is obtained for subsequent performance detection.
The synergistic heat stabilizer provided by the invention is used for improving the thermal stability of PVC, PVC is used as a base material, the butyl titanate modified cerium metal soap complex is used as an auxiliary stabilizer, organic tin is used as a heat stabilizer, and butyl titanate has a remarkable synergistic stabilizing effect on organic tin and cerium metal soap, so that the thermal stability of PVC can be effectively improved.
According to the invention, butyl titanate is used for surface modification, a microwave radiation process is adopted as a green and rapid preparation method, PVC composite films of butyl titanate modified cerium metal soap and organic tin with different addition amounts are prepared, and the hydrogen chloride release rates of different composite films are measured by adopting a 195 ℃ conductivity method. Butyl titanate produces strong synergistic effect with cerium metal soap and organic tin, and has obviously raised heat stability, no toxicity and high environment compatibility.
The method for evaluating the thermal stability of the PVC is conductivity or hydrogen chloride release rate, and the test device refers to ENIS0182-3:2000 standard; introducing high-purity nitrogen into PVC powder, heating to 195 ℃, keeping the temperature constant, and observing the change of the conductivity or the concentration of the hydrogen chloride absorbed and released by deionized water along with time. PVC can be rapidly decomposed to release hydrogen chloride gas at 180-195 ℃, and a platinum electrode in a conductivity meter can rapidly sense the conductivity change of hydrogen protons and chloride ions in deionized water. The composite heat stabilizer is added to inhibit the decomposition of the composite heat stabilizer, and the quality of the effect of the composite heat stabilizer can be judged by measuring the induction period and the stabilization time through a conductivity curve.
Compared with the prior art, the invention has the beneficial effects that:
1. the modifier adopted by the invention is butyl titanate, is environment-compatible and is easy to degrade; the modified cerium metal soap is used as a potential photodecomposition promoter, and can promote the photodegradation of polyvinyl chloride in the environment when the service life of the polyvinyl chloride is ended;
2. the tetrabutyl titanate can promote the generation of electrostatic attraction and chemical bond force between tin and cerium metal soaps and polyvinyl chloride molecules;
3. the butyl titanate has obvious synergistic stabilizing effect on the methyl tin mercaptide and the cerium metal soap, can reduce the using amount of the methyl tin mercaptide, has better effect than that of singly using the methyl tin mercaptide stabilizer, and effectively improves the heat resistance of PVC;
4. the butyl titanate, the methyl tin mercaptide and the cerium metal soap belong to nontoxic or low-toxicity environment-friendly substances, completely meet the development requirements for environmental protection at home and abroad, and have wide application prospects.
Detailed Description
The invention adopts butyl titanate as a coupling agent, and the usage amount of the butyl titanate is 1 to 5 parts per 100 parts of PVC.
Cerium stearate is used as a co-stabilizer, and the using amount of the cerium stearate is 1 to 10 parts by weight of the cerium stearate per 100 parts by weight of PVC, preferably 5 parts by weight of the cerium stearate.
Cerium stearate and microwave heating
100 parts of PVC resin model S-65, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of cerium stearate.
Cerium (di) stearate + conventional heating
100 parts of PVC resin type S-65, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of cerium stearate.
Control + conventional heating
100 parts of PVC resin, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of lanthanum stearate; 100 parts of PVC resin, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of calcium stearate; 100 parts of PVC resin, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of magnesium stearate; 100 parts of PVC resin, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of zinc stearate; 100 parts of PVC resin, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of calcium-zinc.
Control + microwave heating
100 parts of PVC resin, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of lanthanum stearate; 100 parts of PVC resin, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of calcium stearate; 100 parts of PVC resin, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of magnesium stearate; 100 parts of PVC resin, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of zinc stearate; 100 parts of PVC resin, 50 parts of DOTP, 1 part of butyl titanate, 0.5 part of methyl tin mercaptide and 5 parts of calcium-zinc.
Example 1: preparation of PVC/butyl titanate-cerium metal soap-organic tin composite film
Adopting a microwave radiation technology, mixing and dissolving 50 parts by mass of DOTP, 1 part by mass of butyl titanate, 5 parts by mass of cerium metal soap and 0.5 part by mass of organic tin stabilizer, and starting microwave (17% power output) in a microwave oven for mixed radiation for 15min to obtain a uniform precursor; and adding 100 parts by mass of PVC into the obtained precursor, stirring at a high speed to obtain a premix, placing the premix into a small internal mixer for internal mixing, wherein the melting temperature is 170-175 ℃, the screw rotation speed is 40r/min, the internal mixing time is 2-3min, after the torque is rapidly increased and then decreased, and keeping unchanged, taking out the mixed material, and tabletting by using a flat vulcanizing machine at 100 ℃ for 40 seconds to obtain the PVC sheet with the thickness of 1 mm.
Example 2: preparation of PVC/butyl titanate-cerium metal soap-organic tin composite film
Adopting an ultrasonic radiation technology, mixing and dissolving 50 parts by mass of DOTP, 1 part by mass of butyl titanate, 5 parts by mass of cerium metal soap and 0.5 part by mass of organic tin stabilizer, and starting ultrasonic oscillation for 1 hour to obtain a uniform precursor; adding 100 parts by mass of PVC into the obtained precursor, stirring at a high speed to obtain a premix, placing the premix into a small internal mixer for internal mixing, wherein the melting temperature is 170-175 ℃, the screw rotation speed is 40r/min, the internal mixing time is 2-3min, after the torque is rapidly increased and then decreased, and keeping unchanged, taking out the mixed material, and tabletting by using a flat vulcanizing machine at 100 ℃ for 40 seconds to obtain the PVC sheet with the thickness of 1 mm.
TABLE 1 conductivity of hydrogen chloride released by different PVC films under microwave irradiation
(Note: A-methyl tin mercaptide; B) 1 -cerium stearate; b 2 -calcium stearate; b is 3 -magnesium stearate; b is 4 -zinc stearate;B 5 -lanthanum stearate; b 6 - (calcium-zinc) commercial products; c-butyl titanate; all samples contain 100 parts of PVC and 50 parts of DOTP; the power of the microwave oven is 700W; heating strength: 17% power output)
Comparative examples 1-5 use microwave irradiation techniques:
comparative example 1: preparation of PVC/butyl titanate-calcium metal soap-organic tin composite film
Adopting a microwave radiation technology, mixing and dissolving 50 parts by mass of DOTP, 1 part by mass of butyl titanate, 5 parts by mass of calcium metal soap and 0.5 part by mass of organic tin stabilizer, starting microwave (17% power output) in a microwave oven, and performing mixed radiation for 15min to obtain a uniform precursor; and adding 100 parts by mass of PVC into the precursor, stirring at a high speed to obtain a premix, banburying in a small internal mixer at a melting temperature of 170-175 ℃, a screw rotation speed of 40r/min and a banburying time of 2-3min, taking out the mixed material after the torque is rapidly increased and then decreased and is kept unchanged, and tabletting at 100 ℃ for 40 seconds by adopting a flat vulcanizing machine to obtain the PVC sheet with the thickness of 1 mm.
Comparative example 2: preparation of PVC/butyl titanate-magnesium metal soap-organic tin composite film
Adopting a microwave radiation technology, mixing and dissolving 50 parts by mass of DOTP, 1 part by mass of butyl titanate, 5 parts by mass of magnesium metal soap and 0.5 part by mass of organic tin stabilizer, and starting microwave (17% power output) in a microwave oven for mixed radiation for 15min to obtain a uniform precursor; adding 100 parts by mass of PVC into the obtained precursor, stirring at a high speed to obtain a premix, placing the premix into a small internal mixer for internal mixing, wherein the melting temperature is 170-175 ℃, the screw rotation speed is 40r/min, the internal mixing time is 2-3min, after the torque is rapidly increased and then decreased, and keeping unchanged, taking out the mixed material, and tabletting by using a flat vulcanizing machine at 100 ℃ for 40 seconds to obtain the PVC sheet with the thickness of 1 mm.
Comparative example 3: preparation of PVC/butyl titanate-zinc metal soap-organic tin composite film
Adopting a microwave radiation technology, mixing and dissolving 50 parts by mass of DOTP, 1 part by mass of butyl titanate, 5 parts by mass of zinc metal soap and 0.5 part by mass of organic tin stabilizer, and starting microwave (17% power output) in a microwave oven for mixed radiation for 15min to obtain a uniform precursor; adding 100 parts by mass of PVC into the obtained precursor, stirring at a high speed to obtain a premix, placing the premix into a small internal mixer for internal mixing, wherein the melting temperature is 170-175 ℃, the screw rotation speed is 40r/min, the internal mixing time is 2-3min, after the torque is rapidly increased and then decreased, and keeping unchanged, taking out the mixed material, and tabletting by using a flat vulcanizing machine at 100 ℃ for 40 seconds to obtain the PVC sheet with the thickness of 1 mm.
Comparative example 4: preparation of PVC/butyl titanate-lanthanum metal soap-organic tin composite film
Adopting a microwave radiation technology, mixing and dissolving 50 parts by mass of DOTP, 1 part by mass of butyl titanate, 5 parts by mass of lanthanum metal soap and 0.5 part by mass of organic tin stabilizer, starting microwave (17% power output) in a microwave oven, and performing mixed radiation for 15min to obtain a uniform precursor; and adding 100 parts by mass of PVC into the precursor, stirring at a high speed to obtain a premix, banburying in a small internal mixer at a melting temperature of 170-175 ℃, a screw rotation speed of 40r/min and a banburying time of 2-3min, taking out the mixed material after the torque is rapidly increased and then decreased and is kept unchanged, and tabletting at 100 ℃ for 40 seconds by adopting a flat vulcanizing machine to obtain the PVC sheet with the thickness of 1 mm.
Comparative example 5: PVC/butyl titanate- (calcium-zinc) * Preparation of organotin composite film
Adopting microwave radiation technology, taking 50 parts by mass of DOTP, 1 part by mass of butyl titanate and (calcium-zinc) * 5 parts by mass and 0.5 part by mass of an organic tin stabilizer are mixed and dissolved, and the mixture is radiated for 15min by starting microwave (with 17% power output) in a microwave oven to obtain a uniform precursor; and adding 100 parts by mass of PVC into the precursor, stirring at a high speed to obtain a premix, banburying in a small internal mixer at a melting temperature of 170-175 ℃, a screw rotation speed of 40r/min and a banburying time of 2-3min, taking out the mixed material after the torque is rapidly increased and then decreased and is kept unchanged, and tabletting at 100 ℃ for 40 seconds by adopting a flat vulcanizing machine to obtain the PVC sheet with the thickness of 1 mm.
Comparative examples 6-10 use ultrasonic irradiation:
comparative example 6: preparation of PVC/butyl titanate-calcium metal soap-organic tin composite film
Adopting an ultrasonic radiation technology, mixing and dissolving 100 parts by mass of PVC, 50 parts by mass of DOTP, 1 part by mass of butyl titanate, 5 parts by mass of calcium metal soap and 0.5 part by mass of organic tin stabilizer, and performing ultrasonic stirring for 1 hour at 40 ℃ to obtain a uniform premix; and (3) banburying the obtained premix in a small internal mixer, wherein the melt temperature is 170-175 ℃, the screw rotation speed is 40r/min, the banburying time is 2-3min, after the torque is rapidly increased and then decreased and is kept unchanged, the mixed material is taken out, and tabletting is carried out for 40 seconds at 100 ℃ by adopting a flat vulcanizing machine, so that the PVC sheet with the thickness of 1mm is obtained.
Comparative example 7: preparation of PVC/butyl titanate-magnesium metal soap-organic tin composite film
Adopting an ultrasonic radiation technology, mixing and dissolving 100 parts by mass of PVC, 50 parts by mass of DOTP, 1 part by mass of butyl titanate, 5 parts by mass of magnesium metal soap and 0.5 part by mass of organic tin stabilizer, and performing ultrasonic stirring for 1 hour at 40 ℃ to obtain a uniform premix; and (3) banburying the obtained premix in a small internal mixer, wherein the melt temperature is 170-175 ℃, the screw rotation speed is 40r/min, the banburying time is 2-3min, after the torque is rapidly increased and then decreased and is kept unchanged, the mixed material is taken out, and tabletting is carried out for 40 seconds at 100 ℃ by adopting a flat vulcanizing machine, so that the PVC sheet with the thickness of 1mm is obtained.
Comparative example 8: preparation of PVC/butyl titanate-zinc metal soap-organic tin composite film
Adopting an ultrasonic radiation technology, mixing and dissolving 100 parts by mass of PVC, 50 parts by mass of DOTP, 1 part by mass of butyl titanate, 5 parts by mass of zinc metal soap and 0.5 part by mass of organic tin stabilizer, and performing ultrasonic stirring for 1 hour at 40 ℃ to obtain a uniform premix; and (3) banburying the obtained premix in a small internal mixer, wherein the melt temperature is 170-175 ℃, the screw rotation speed is 40r/min, the banburying time is 2-3min, after the torque is rapidly increased and then decreased and is kept unchanged, the mixed material is taken out, and tabletting is carried out for 40 seconds at 100 ℃ by adopting a flat vulcanizing machine, so that the PVC sheet with the thickness of 1mm is obtained.
Comparative example 9: preparation of PVC/butyl titanate-lanthanum metal soap-organic tin composite film
Adopting an ultrasonic radiation technology, mixing and dissolving 100 parts by mass of PVC, 50 parts by mass of DOTP, 1 part by mass of butyl titanate, 5 parts by mass of lanthanum metal soap and 0.5 part by mass of organic tin stabilizer, and performing ultrasonic stirring for 1 hour at 40 ℃ to obtain a uniform premix; and (3) banburying the obtained premix in a small internal mixer, wherein the melt temperature is 170-175 ℃, the screw rotation speed is 40r/min, the banburying time is 2-3min, after the torque is rapidly increased and then decreased and is kept unchanged, the mixed material is taken out, and tabletting is carried out for 40 seconds at 100 ℃ by adopting a flat vulcanizing machine, so that the PVC sheet with the thickness of 1mm is obtained.
Comparative example 10: preparation of PVC/butyl titanate- (calcium-zinc) organic tin composite film
Adopting ultrasonic radiation technology, taking 100 parts by mass of PVC, 50 parts by mass of DOTP, 1 part by mass of butyl titanate, (calcium-zinc) * 5 parts by mass and 0.5 part by mass of an organic tin stabilizer are mixed and dissolved, and the mixture is ultrasonically stirred for 1 hour at the temperature of 40 ℃ to obtain a uniform premix; and (3) banburying the obtained premix in a small internal mixer, wherein the melt temperature is 170-175 ℃, the screw rotation speed is 40r/min, the banburying time is 2-3min, after the torque is rapidly increased and then decreased and is kept unchanged, the mixed material is taken out, and tabletting is carried out for 40 seconds at 100 ℃ by adopting a flat vulcanizing machine, so that the PVC sheet with the thickness of 1mm is obtained.
TABLE 2 conductivity of hydrogen chloride released by different PVC films under conventional heating
(Note: A-methyl tin mercaptide; B) 1 -cerium stearate; b is 2 -calcium stearate; b is 3 -magnesium stearate; b is 4 -zinc stearate; b is 5 -lanthanum stearate; b 6 - (calcium-zinc) * A commercially available commercial product; c-butyl titanate; all samples contained PVC-100 parts, DOTP-50 parts)
The evaluation method of the PVC thermal stability comprises the following steps: the conductivity of the aqueous hydrogen chloride solution released was determined, with reference to ENIS0182-3:2000 standard; introducing high-purity nitrogen into a PVC powder heating test tube, using silicone oil as an oil bath, heating at 195 ℃, and observing the change curve of the conductivity of the deionized water absorbing and releasing hydrogen chloride along with time.
The PVC sample can be decomposed to release hydrogen chloride gas at 180-195 ℃, and a platinum electrode in the conductivity meter can quickly sense the conductivity change of hydrogen protons and chloride ions in deionized water. The composite stabilizer is added to inhibit the decomposition of the heat stabilizer, and the quality of the effect of the heat stabilizer can be judged by measuring the induction period and the stabilization time through a conductivity curve.
As can be seen from Table 1, table 2 and FIG. 1, when heated conventionally, the metal soaps of calcium, magnesium, zinc, lanthanum, cerium, (calcium-zinc) * The induction periods of hydrogen chloride released by the thermal degradation of PVC are respectively 60, 88, 45, 57, 60 and 36min in a nitrogen atmosphere at 195 ℃, and under the same condition, the induction periods of hydrogen chloride released by the thermal degradation of PVC are respectively 70, 75, 42, 45, 53 and 33min by adopting microwave (17% power output) radiation for 15min, so that the induction period of the thermal degradation of PVC only containing cerium metal soap is prolonged by 10min, and the rest of calcium, magnesium, zinc, lanthanum and (calcium-zinc) * Drop 13, 3, 12, 7 and 3min respectively. Thus, in addition to the cerium metal soaps of examples 1 and 2, microwave heating is more conventional, and only the cerium metal soaps can enhance the thermal stability of the PVC film; for calcium, magnesium, zinc, lanthanum metal soaps and (calcium-zinc) * Compared with conventional heating, the microwave heating reduces the heat-resistant stability of the PVC film, namely the stability is in a descending trend. As shown in comparative examples 1-10.
TABLE 3 conductivity of hydrogen chloride released by PVC films at different irradiation times
(Note: A-methyl tin mercaptide; B) 1 -cerium stearate; c-butyl titanate; the samples contain 100 parts of PVC and 50 parts of DOTP; the power of the microwave oven is 700W; heating strength: 17% power output)
Table 3 shows that the conductivity of the PVC film releasing hydrogen chloride at different irradiation times increases, and when the microwave irradiation is increased from 5min in example 3 to 15min in example 1, the induction period of the PVC film releasing hydrogen chloride is increased from 50min to 70min, so that the irradiation time is prolonged, and the heat resistance of the PVC film is improved.