Method for preparing polyvinyl chloride resin with reduced leather diaphragm and improved porosity

A polyvinyl chloride resin and porosity technology, which is applied in the field of polyvinyl chloride resin to reduce the film and increase the porosity, can solve the problems of difficult to control the granulation process, coarse resin particles, coarse resin particles, etc., and achieve the concentration of particle size distribution, The effect of high porosity and regular particles

Active Publication Date: 2010-06-02
SHANGHAI CHLOR ALKALI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This technology uses a special type of dispersant, the operation is complicated, and it is difficult to control the granulation process.
[0006] At the same time, B.F.Goodrich Chemical Company also introduced a new additive that can adjust the molecular weight of the resin and improve the porosity of the resin, US 4,963,592, such as 2-mercaptophenylpropanthiazole, 2-mercaptophenylpropanoxazole, 2-mercaptophenylpropanoid imidazole, etc., but this kind of additive is easy to make the resin particles too thick, beyond the normal range
[0007] Domestic

Method used

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  • Method for preparing polyvinyl chloride resin with reduced leather diaphragm and improved porosity
  • Method for preparing polyvinyl chloride resin with reduced leather diaphragm and improved porosity

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] The polymerization reaction is stirred as a two-leaf three-layer flat paddle, two symmetrical baffles, and a volume of 7M 3 in the kettle.

[0054] The technical conditions and process are briefly described as follows: First, 3.50t desalted water, 0.15kg dispersant A, 0.30kg dispersant B, 0.20kg 2-mercaptoethanol, 0.50kg NH 4 HCO 3 Put it into the kettle, add 2.30t of vinyl chloride monomer after pressure testing and vacuuming, inject 1.65kg of initiator bis-(2-ethylhexyl peroxydicarbonate) with a metering pump, start stirring, and maintain the power per unit volume at 0.80 kw / m 3 , the temperature is raised to 62°C to start constant temperature polymerization; when the polymerization conversion rate is 15%, add 0.20kg dispersant C with a metering pump, and the power per unit volume changes to 1.00kw / m 3 , continue polymerization; when the polymerization conversion rate is 35%, add 0.15kg dispersant C with a metering pump, and the power per unit volume changes to 1.2...

Embodiment 2

[0058] Change the add-on of dispersant A to 0.20kg, change the add-on of dispersant B to 0.50kg, when the polymerization conversion rate is 15%, add 0.15kg dispersant C with metering pump, when the polymerization conversion rate is 35%, Add 0.2kg dispersant C with metering pump, other technological conditions are with embodiment 1, and its test result is as follows: degree of polymerization is 800, and apparent density is 0.54 (g / ml), porosity 0.28 (ml / g), average particle size The diameter is 150.0 (μm), the distribution width is 0.710, and the film coverage is 40%.

Embodiment 3

[0060] When the polymerization conversion rate reaches 15%, the add-on of dispersant C becomes 0.20kg, and when the conversion rate reaches 35%, the add-on of powder C becomes 0.30kg, and other process conditions are with embodiment 1, and its test result is as follows: the degree of polymerization is 800, and the The apparent density is 0.56 (g / ml), the porosity is 0.24 (ml / g), the average particle size is 140.0 (μm), the distribution width is 0.710, and the film coverage is 45%.

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Abstract

The invention provides a method for preparing a polyvinyl chloride resin with reduced leather diaphragm and improved porosity, which comprises the following steps of: (1) putting water, a dispersant A, a dispersant B, a chain transfer agent, a pH regulator, a vinyl chloride monomer and an initiator into a reaction kettle to perform polymerization when the stirring power per unit volume is 0.70 to 0.90 kw/m3; (2) when the polymerization conversion is 12 to 20 percent, adding a dispersant C to perform the polymerization continuously when the stirring power per unit volume is changed to be 0.9 to 1.40 kw/m3; and 3) when the polymerization conversion is 30 to 45 percent, adding the dispersant C, performing the polymerization continuously when the stirring power per unit volume is changed to be 1.00 to 1.60 kw/m3, and ending the reaction when the polymerization pressure is reduced to be 0.15 to 0.30 MPa to obtain a product. The PVC resin prepared by the method has fewer leather diaphragms on particle surfaces, and has loosened and porous interior, high porosity and even pore distribution, and the absorptive amount of a plasticizer is high.

Description

technical field [0001] The invention relates to a method for preparing polyvinyl chloride resin by adopting a suspension polymerization method. Background technique [0002] Polyvinyl chloride (PVC) resin is generally a white powder with a particle size range of 100-200um. In addition to the molecular weight index, the most important performance of PVC resin is the particle characteristics, which are reflected in the index as the average particle size and its distribution, apparent density, plasticizer absorption rate, sieving rate, etc., which directly affect the melt fluidity of the resin during processing. , plasticizing time, appearance of the product, etc. PVC resin is widely used in the manufacture of pipes, pipe fittings, sheets, films and other fields, and can be further chlorinated to produce chlorinated polyvinyl chloride resin (CPVC). PVC resin has high porosity and uniform distribution, less film, suitable particle size range and concentrated distribution, good...

Claims

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Application Information

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IPC IPC(8): C08F114/06C08F2/20
Inventor 缪晖袁茂全刘松涛张月芳
Owner SHANGHAI CHLOR ALKALI CHEM
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