A suspension-process high-whiteness polyvinyl chloride resin and its production method

Abstract

The present invention discloses a suspension method high-whiteness polyvinyl chloride resin and a production method thereof, which belongs to the field of PVC polymer synthesis, and specifically relates to a high-whiteness polyvinyl chloride resin production process. The present invention adopts a suspension method to prepare a polyvinyl chloride resin process, which includes the following steps: adding deionized water, a dispersant, an initiator, and a vinyl chloride monomer to a polymerization kettle, adding an antioxidant after a period of time after the polymerization reaction starts, and drying the produced polyvinyl chloride resin slurry in a constant temperature oven after the reaction ends to obtain a polyvinyl chloride resin. The polyvinyl chloride resin produced by the present invention has the characteristics of high whiteness, good heat resistance, and excellent processing performance; the production method proposed by the present invention has a simple and easy-to-control production process, and has no effect on the other properties of the produced PVC resin. The whiteness and thermal stability of the prepared PVC resin are much higher than those of the general-purpose PVC resin, which is conducive to expanding the application field of the PVC resin, greatly extending the service life of PVC products, and affecting the processing technology of downstream enterprises.

Description

Technical Field

[0001] The invention discloses a suspension-process high-whiteness polyvinyl chloride resin and a production method thereof, belonging to the field of PVC polymer synthesis. Background Art

[0002] As one of the five general-purpose resins, polyvinyl chloride (PVC) resin has excellent physical and mechanical properties such as corrosion resistance, plasticity, and electrical insulation. It is widely used in building materials, medical equipment, electronic appliances, industrial products, etc.

[0003] The national standard GB / T5761-2018 stipulates that whiteness is an important indicator of the quality of PVC resin products. It can characterize the thermal stability of PVC to a certain extent. The thermal stability of PVC directly affects the processing technology of downstream products and the aging resistance and appearance of products. At present, although the whiteness of domestic PVC resin meets the national standards, it is relatively low. As customers have higher and higher requirements for product performance, downstream companies are also paying more and more attention to the whiteness performance of PVC resin. Subsequent PVC products will develop in the direction of high whiteness, high stability, and beautiful products. Improving the whiteness of PVC resin without affecting other properties of the resin can greatly meet the requirements of downstream companies for resin performance, open up markets for companies, and enhance market competitiveness. Summary of the invention

[0004] The purpose of the present invention is to solve the problem of low whiteness of polyvinyl chloride resin products produced by a suspension process, and to provide a suspension process high-whiteness polyvinyl chloride resin and a production method thereof.

[0005] The technical solution adopted by the present invention to solve the above problems is as follows: A suspension process high-whiteness polyvinyl chloride resin and a production method thereof, the production steps are: adding deionized water, a dispersant and an initiator into a 5L closed polymerization kettle; adding vinyl chloride monomer after vacuuming, and starting polymerization reaction under certain stirring and temperature; adding a certain amount of antioxidant after a period of reaction, releasing the pressure and discharging the material after the reaction is completed to obtain polyvinyl chloride resin slurry, and bagging after drying in a constant temperature oven at 55°C.

[0006] Taking into account the filling coefficient and utilization rate of the polymerization reactor, the water-oil ratio is 1.0:1.0-3.0:1.0, and examples thereof include 1.0:1.0, 1.3:1.0, 1.5:1.0, 1.7:1.0, 2.0:1.0, 2.4:1.0, 2.6:1.0, 2.8:1.0, and 3.0:1.0. Preferably, the water-oil ratio is 1.5:1.0.

[0007] The total amount of the dispersant and the initiator is 0.10-30% of the monomer amount, and the amounts thereof include 0.10%, 0.12%, 0.15%, 0.17%, 0.20%, 0.22%, 0.25%, 0.27%, and 0.30%. Preferably, the amount of the auxiliary agent is 0.20% of the monomer amount.

[0008] The dispersant and the initiator are added in a single sequence.

[0009] The inventors have considered the apparent density and porosity of the PVC resin, and the dispersant is a composite of polyvinyl alcohol and hydroxypropyl methylcellulose, and the composite ratio is 1.0:1.0~3.0:1.0, and the examples include 1.0:1.0, 1.3:1.0, 1.5:1.0, 1.8:1.0, 2.0:1.0, 2.3:1.0, 2.5:1.0, 2.8:1.0, and 3.0:1.0. Preferably, the composite ratio of polyvinyl alcohol to hydroxypropyl methylcellulose is 2.5:1.0.

[0010] The dispersant compounding method is to add the dispersants into the polymerization kettle in sequence according to proportion, or add them into the polymerization kettle after mixing them in proportion.

[0011] The inventors took into account the polymerization reaction rate and productivity, and the initiator is a compound of one of isopropyl peroxyneodecanoate and di-3-methoxybutyl peroxydicarbonate and one of dioctyl peroxydicarbonate, peroxy bis(3,5,5-trimethylhexanoyl), tert-butyl peroxyneodecanoate, isopropyl peroxyneoheptanoate, and tert-butyl peroxyneoheptanoate, and the compound ratio is 1.0:1.0~5.0:1.0, and the examples include 1.0:1.0, 1.5:1.0, 2.0:1.0, 2.5:1.0, 3.0:1.0, 3.5:1.0, 4.0:1.0, 4.5:1.0, and 5.0:1.0.

[0012] Preferably, the initiator is a composite of cumyl peroxyneodecanoate and dioctyl peroxydicarbonate, with the composite ratio being 4.5:1.0.

[0013] The initiator is non-toxic, safe and low-residue initiator; the compounding method is to add the initiators into the polymerization kettle in sequence according to proportion, or add them into the polymerization kettle after mixing them in proportion; the temperature is below 10°C when the initiators are mixed in proportion.

[0014] The inventors consider the particle size and shape of PVC resin, and the polymerization reaction stirring speed is 1000-1500r / min, and the examples include 1000r / min, 1050r / min, 1100r / min, 1155r / min, 1200r / min, 1250r / min, 1300r / min, 1350r / min, 1400r / min, 1450r / min, 1500r / min. Preferably, the polymerization reaction stirring speed is 1200r / min.

[0015] The polymerization reaction temperature is 55-57° C., and examples thereof include 55° C., 55.5° C., 56° C., 56.5° C., and 57° C. Preferably, the polymerization reaction temperature is 57° C.

[0016] The antioxidant is a compound of one or more antioxidants in any proportion; the compounding method is to add the antioxidants into the polymerization kettle in sequence according to proportion, or to add them into the polymerization kettle after mixing them in proportion.

[0017] The inventors found that if the amount of antioxidant is too little, the aging whiteness of PVC resin is not significantly improved; if the amount of antioxidant is too much, the aging whiteness of PVC resin decreases. Considering the antioxidant effect of the antioxidant system, the amount of antioxidant added is 0.10-0.18% of the amount of monomer used, and the following can be cited: 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%. Preferably, the amount of antioxidant added is 0.12% and 0.18% of the amount of monomer used.

[0018] The inventors have considered the molding time of PVC, and the antioxidant is added 90 to 240 minutes after the polymerization reaction begins, and examples thereof include 90 minutes, 100 minutes, 110 minutes, 120 minutes, 130 minutes, 140 minutes, 150 minutes, 160 minutes, 170 minutes, 180 minutes, 190 minutes, 200 minutes, 210 minutes, 220 minutes, 230 minutes, and 240 minutes. Preferably, the antioxidant is added 90 minutes, 210 minutes, and 240 minutes after the polymerization reaction begins.

[0019] The inventors have considered the conversion rate of PVC, and the antioxidant is added in a one-time addition, intermittent addition or continuous dripping manner; the intermittent addition or continuous dripping speed is uniform or variable speed addition, and the addition time is controlled within 20 minutes.

[0020] The advantages of adopting the present invention are: The present invention adopts a binary composite peroxide initiator system and a binary composite dispersant system. The antioxidant is added after a certain period of time after the polymerization reaction begins, which will not affect the effects of the initiator and the dispersant, and will not affect the polymerization reaction rate and the particle morphology of the product.

[0021] The invention provides a suspension method high-whiteness polyvinyl chloride resin and a production method thereof, the production process is simple, the reaction process is stable and easy to control, no harmful substances that pollute the environment are generated during the production process, and the produced PVC resin has excellent properties.

[0022] Compared with the method for improving the aging whiteness of PVC resin disclosed in patent CN107011588A, the present invention is carried out during the polymerization reaction, has no influence on the subsequent production, and has no residue in the recovered monomer, which does not affect the reuse of the monomer.

[0023] (4) The aging whiteness of the PVC resin produced by the present invention is stable at 85-88%, which is much higher than the national standard GB / T5761-2018 superior product index of 78%. The resin product has good stability, excellent processing performance, and good color, which can meet the requirements of downstream enterprises for resin whiteness. Implementation

[0024] The following is a further description of a suspension-process high-whiteness polyvinyl chloride resin and a production method thereof according to the present invention through specific implementation cases. Example

[0025] A suspension-process high-whiteness polyvinyl chloride resin and a production method thereof, comprising the following components in parts by weight: 160 parts of vinyl chloride monomer, 240 parts of deionized water, Dispersant 0.22 parts, Initiator 0.10 parts, Antioxidant 0 parts; The production steps are as follows: add deionized water, dispersant and initiator to a 5L closed polymerization kettle; add vinyl chloride monomer after vacuuming, adjust the stirring speed to 1200r / min, and heat to 57°C through the oil bath circulation system of the polymerization kettle jacket to start the polymerization reaction; after the reaction is completed, release the pressure and discharge the material to obtain polyvinyl chloride resin slurry, which is dried in a constant temperature oven at 55°C and then bagged.

[0026] The dispersant is a composite of polyvinyl alcohol and hydroxypropyl methylcellulose, and the composite ratio is 2.5:1.0.

[0027] The initiator is a composite of cumyl peroxyneodecanoate and dioctyl peroxydicarbonate, with a composite ratio of 4.5:1.0. Example

[0028] A suspension-process high-whiteness polyvinyl chloride resin and a production method thereof, comprising the following components in parts by weight: 160 parts of vinyl chloride monomer, 240 parts of deionized water, Dispersant 0.22 parts, Initiator 0.10 parts, Antioxidant 0.20 parts; The production steps are as follows: add deionized water, dispersant and initiator to a 5L closed polymerization kettle; add vinyl chloride monomer after vacuuming, adjust the stirring speed to 1200r / min, raise the temperature to 57°C through the oil bath circulation system of the polymerization kettle jacket to start the polymerization reaction, and add 0.20 parts of antioxidant after the reaction for 90 minutes; after the reaction is completed, release the pressure and discharge the material to obtain polyvinyl chloride resin slurry, which is dried in a constant temperature oven at 55°C and then bagged.

[0029] The dispersant is a composite of polyvinyl alcohol and hydroxypropyl methylcellulose, and the composite ratio is 2.5:1.0.

[0030] The initiator is a composite of cumyl peroxyneodecanoate and dioctyl peroxydicarbonate, with a composite ratio of 4.5:1.0.

[0031] The antioxidant was added by continuous dripping at a uniform speed and the addition was completed within 20 minutes. Example

[0032] A suspension-process high-whiteness polyvinyl chloride resin and a production method thereof, comprising the following components in parts by weight: 160 parts of vinyl chloride monomer, 240 parts of deionized water, Dispersant 0.22 parts, Initiator 0.10 parts, Antioxidant 0.28 parts; The production steps are as follows: add deionized water, dispersant and initiator to a 5L closed polymerization kettle; add vinyl chloride monomer after vacuuming, adjust the stirring speed to 1200r / min, raise the temperature to 57°C through the oil bath circulation system of the polymerization kettle jacket to start the polymerization reaction, and add 0.28 parts of antioxidant after the reaction for 90 minutes; after the reaction is completed, release the pressure and discharge the material to obtain polyvinyl chloride resin slurry, which is dried in a constant temperature oven at 55°C and then bagged.

[0033] The dispersant is a composite of polyvinyl alcohol and hydroxypropyl methylcellulose, and the composite ratio is 2.5:1.0.

[0034] The initiator is a composite of cumyl peroxyneodecanoate and dioctyl peroxydicarbonate, with a composite ratio of 4.5:1.0.

[0035] The antioxidant was added by continuous dripping at a uniform speed and the addition was completed within 20 minutes. Example

[0036] A suspension-process high-whiteness polyvinyl chloride resin and a production method thereof, comprising the following components in parts by weight: 160 parts of vinyl chloride monomer, 240 parts of deionized water, Dispersant 0.22 parts, Initiator 0.10 parts, Antioxidant 0.20 parts; The production steps are as follows: add deionized water, dispersant and initiator to a 5L closed polymerization kettle; add vinyl chloride monomer after vacuuming, adjust the stirring speed to 1200r / min, raise the temperature to 57°C through the oil bath circulation system of the polymerization kettle jacket to start the polymerization reaction, and add 0.20 parts of antioxidant after reacting for 210 minutes; after the reaction is completed, release the pressure and discharge the material to obtain polyvinyl chloride resin slurry, which is dried in a constant temperature oven at 55°C and then bagged.

[0037] The dispersant is a composite of polyvinyl alcohol and hydroxypropyl methylcellulose, and the composite ratio is 2.5:1.0.

[0038] The initiator is a composite of cumyl peroxyneodecanoate and dioctyl peroxydicarbonate, with a composite ratio of 4.5:1.0.

[0039] The antioxidant was added in a continuous dripping manner, first slowly and then quickly, and the addition was completed within 20 minutes. Example

[0040] A suspension-process high-whiteness polyvinyl chloride resin and a production method thereof, comprising the following components in parts by weight: 160 parts of vinyl chloride monomer, 240 parts of deionized water, Dispersant 0.22 parts, Initiator 0.10 parts, Antioxidant 0.28 parts; The production steps are as follows: add deionized water, dispersant and initiator to a 5L closed polymerization kettle; add vinyl chloride monomer after vacuuming, adjust the stirring speed to 1200r / min, raise the temperature to 57°C through the oil bath circulation system of the polymerization kettle jacket to start the polymerization reaction, and add 0.28 parts of antioxidant after reacting for 210 minutes; after the reaction is completed, release the pressure and discharge the material to obtain polyvinyl chloride resin slurry, which is dried in a constant temperature oven at 55°C and then bagged.

[0041] The dispersant is a composite of polyvinyl alcohol and hydroxypropyl methylcellulose, and the composite ratio is 2.5:1.0.

[0042] The initiator is a composite of cumyl peroxyneodecanoate and dioctyl peroxydicarbonate, with a composite ratio of 4.5:1.0.

[0043] The antioxidant was added in a continuous dripping manner, first slowly and then quickly, and the addition was completed within 20 minutes. Example

[0044] A suspension-process high-whiteness polyvinyl chloride resin and a production method thereof, comprising the following components in parts by weight: 160 parts of vinyl chloride monomer, 240 parts of deionized water, Dispersant 0.22 parts, Initiator 0.10 parts, Antioxidant 0.20 parts; The production steps are as follows: add deionized water, dispersant and initiator to a 5L closed polymerization kettle; add vinyl chloride monomer after vacuuming, adjust the stirring speed to 1200r / min, raise the temperature to 57°C through the oil bath circulation system of the polymerization kettle jacket to start the polymerization reaction, and add 0.20 parts of antioxidant after reacting for 240 minutes; after the reaction is completed, release the pressure and discharge the material to obtain polyvinyl chloride resin slurry, which is dried in a constant temperature oven at 55°C and then bagged.

[0045] The dispersant is a composite of polyvinyl alcohol and hydroxypropyl methylcellulose, and the composite ratio is 2.5:1.0.

[0046] The initiator is a composite of cumyl peroxyneodecanoate and dioctyl peroxydicarbonate, with a composite ratio of 4.5:1.0.

[0047] The antioxidant is added in one go. Example

[0048] A suspension-process high-whiteness polyvinyl chloride resin and a production method thereof, comprising the following components in parts by weight: 160 parts of vinyl chloride monomer, 240 parts of deionized water, Dispersant 0.22 parts, Initiator 0.10 parts, Antioxidant 0.28 parts; The production steps are as follows: add deionized water, dispersant and initiator to a 5L closed polymerization kettle; add vinyl chloride monomer after vacuuming, adjust the stirring speed to 1200r / min, raise the temperature to 57°C through the oil bath circulation system of the polymerization kettle jacket to start the polymerization reaction, and add 0.28 parts of antioxidant after reacting for 240 minutes; after the reaction is completed, release the pressure and discharge the material to obtain polyvinyl chloride resin slurry, which is dried in a constant temperature oven at 55°C and then bagged.

[0049] The dispersant is a composite of polyvinyl alcohol and hydroxypropyl methylcellulose, and the composite ratio is 2.5:1.0.

[0050] The initiator is a composite of cumyl peroxyneodecanoate and dioctyl peroxydicarbonate, with a composite ratio of 4.5:1.0.

[0051] The antioxidant is added in one go.

[0052] The PVC resins prepared in Examples 1-7 were sampled and tested, and the whiteness was tested according to the national standard GB / T5761-2018. The amount and time of addition of the antioxidants in each example, the original whiteness and the aged whiteness are shown in Table 1.

[0053] Table 1 Comparison of antioxidant addition amount, addition time and aging whiteness As can be seen from Table 1, the aging whiteness of the PVC resin produced by the present invention is stabilized at 85-88%, which is much higher than the national standard GB / T5761-2018 superior product index of 78%, and the best solution is Example 6, that is, 0.20 parts of antioxidant are added 240 minutes after the start of the polymerization reaction. The aging whiteness of the PVC resin produced by the present invention is significantly improved compared with the aging whiteness of the PVC resin produced without adding antioxidants.

[0054] The above is only a preferred embodiment of the present invention, and is not intended to limit other forms of the present invention. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A suspension process high whiteness polyvinyl chloride resin and a production method thereof, characterized in that: The production steps are as follows: add deionized water, dispersant and initiator into a 5L closed polymerization kettle; add vinyl chloride monomer after vacuuming, and start the polymerization reaction under certain stirring and temperature; add a certain amount of antioxidant after a period of reaction, release the pressure and discharge the material after the reaction is completed to obtain polyvinyl chloride resin slurry, which is dried in a constant temperature oven at 55°C and then bagged.

2. A high whiteness polyvinyl chloride resin and a production method thereof according to claim 1, characterized in that: The water-to-oil ratio is 1.0:1.0~3.0:1.

0.

3. A high whiteness polyvinyl chloride resin and a production method thereof according to claim 1, characterized in that: The total amount of the dispersant and initiator is 0.10-0.30% of the monomer amount.

4. A high whiteness polyvinyl chloride resin and a production method thereof according to claim 1, characterized in that: The dispersant is a compound of polyvinyl alcohol and hydroxypropyl methylcellulose, and the compound ratio is 1.0:1.0-3.0:1.

0.

5. A suspension process high whiteness polyvinyl chloride resin and its production method according to claim 1, characterized in that: The initiator is a composite of one of isopropylbenzene peroxyneodecanoate and di-3-methoxybutyl peroxydicarbonate and one of dioctyl peroxydicarbonate, bis(3,5,5-trimethylhexanoyl) peroxide, tert-butyl peroxyneodecanoate, isopropylbenzene peroxyneoheptanoate and tert-butyl peroxyneoheptanoate, and the composite ratio is 1.0:1.0-5.0:1.

0.

6. A suspension process high whiteness polyvinyl chloride resin and its production method according to claim 1, characterized in that: The antioxidant is a compound of one or more antioxidants in any proportion.

7. A suspension process high whiteness polyvinyl chloride resin and a production method thereof according to claims 4 to 6, characterized in that: The composite method of the dispersant, initiator and antioxidant is to add the dispersant, initiator or antioxidant into the polymerization kettle in sequence according to proportion, or to add them into the polymerization kettle after mixing them in proportion.

8. A suspension process high whiteness polyvinyl chloride resin and its production method according to claim 1, characterized in that: The amount of the antioxidant added is 0.10-0.18% of the amount of the monomer.

9. A suspension process high whiteness polyvinyl chloride resin and its production method according to claim 1, characterized in that: The antioxidant is added in one-time addition, intermittent addition or continuous dropwise addition.

10. A suspension process high whiteness polyvinyl chloride resin and its production method according to claim 1, characterized in that: The antioxidant is added 90 to 240 minutes after the polymerization reaction begins.