CN1200023C - Method for synthesizing resin with high water absorption by using polystyrene - Google Patents

Abstract

The present invention relates to a method for synthesizing resin with high water absorption through polystyrene. The method comprises the following technological steps: sodium acrylate is dissolved in an amount of water, and polystyrene is dissolved through mixed solvent. The two solutions are mixed together, and an initiating agent, a dispersing agent, a coupling agent and a crosslinking agent are added into the solution mixture and sheared in a water bath to fully react with the mixture at 60 to 80 DEG C under protective atmosphere so as to be solidified into the resin with high water absorption at 110 to 130 DEG C. The raw materials used in a technology contain 50 to 95.5 WT% of sodium acrylate, 2.5 to 47WT% of polystyrene, 1.5 to 3WT% of dispersing agent, 0.07 to 0.4 WT% of coupling agent, 0.1 to 0.5 WT% of initiating agent and 0.05 to 0.6WT% of crosslinking agent. With the method, waste foam plastics are properly recovered and reused and are changed into valuables on one hand, and on the other hand, the manufacture cost of the resin with high water absorption can be reduced, and the competitive power of a product is enhanced.

Description

Method for Synthesizing Super Absorbent Resin Using Polystyrene

technical field

The invention relates to a method for synthesizing superabsorbent resin by using a waste polystyrene plastic.

Background technique

The development of superabsorbent resin has only a few decades of history, and it has been developed abroad since the 1960s. my country only synthesized the first superabsorbent resin in 1982, and it was not until 1988 that the first patent was obtained. There are many kinds of superabsorbent resins, which are mainly divided into three categories: starch, cellulose and synthetic resin according to the source. The product performance of these methods gained is all better, but the raw material that adopts is all regular industrial products, and cost is higher. At present, there are not many technologies for synthesizing superabsorbent resins from waste resources in China. After querying databases such as China Journal Network, Wanfang Database, VIP Database, Jinbao Xingtu Full-text Database, China Economic Special Network and China Patent Network, no polystyrene foam was used as raw material to synthesize superabsorbent resin similar work.

Styrofoam is widely used in the packaging of household appliances, instruments, special handicrafts and fast food because of its light weight, cheap price and strong strength. With the development of the economy, its consumption is increasing. And because it cannot be degraded by itself in the natural environment, it not only causes serious white pollution, but also causes a great waste of resources.

Contents of the invention

The object of the present invention is to provide a superabsorbent resin that is grafted and blended with polystyrene foam and acrylate. On the one hand, waste foam plastics can be properly recycled and reused, turning waste into treasure; on the other hand, it can also reduce the manufacturing cost of superabsorbent resin and enhance the competitiveness of products.

The method adopts a mixed solvent to first dissolve polystyrene, and then carries out graft copolymerization with acrylate in the presence of an initiator, a dispersant, a coupling agent and a crosslinking agent.

The process steps are as follows:

  Dissolve sodium acrylate in an appropriate amount of water,

  Dissolve polystyrene with a mixed solvent,

  Mix the above two solutions together,

  Add initiator, dispersant, coupling agent, crosslinking agent, shear emulsification in water bath,

Fully react at 60-80°C under protective atmosphere,

Cures into a super absorbent resin at 110-130°C.

Raw material ratio used in the above technique is (WT%):

Sodium acrylate 50～95.5%

Polystyrene 2.5～47%

Dispersant 1.5～3%

Coupling agent 0.07～0.4%

Initiator 0.1～0.5%

Cross-linking agent 0.05-0.6%.

The appropriate amount of water mentioned here refers to: enough water to dissolve sodium acrylate (too much water will increase the evaporation in the follow-up process); said mixed solvent refers to the mixture of two or more traditional organic solvents. The solvent is, for example, ethyl acetate, toluene, cyclohexane or a mixed solvent of ethyl acetate, toluene, and cyclohexanone. Said initiator can be the combination of ammonium persulfate and sodium bisulfite, or the combination of hydrogen peroxide and sodium bisulfite; dispersant can be: Span-60 or sodium dodecylbenzenesulfonate; coupling agent It can be: azobisisobutyronitrile or polyethylene glycol 600; the cross-linking agent can be ethanol solution of epichlorohydrin or glycerin. The protective atmosphere mentioned is a non-oxidizing atmosphere or an inert atmosphere, such as nitrogen, carbon dioxide, etc. The following formulas and processes are specifically recommended:

Raw material (WT%)

Sodium acrylate 94.1～50.9%

Polystyrene 3.4～45.2%

Siban-60 2.18～2.90%

Azobisisobutyronitrile 0.03～0.3%

Ammonium persulfate 0.09～0.3%

Sodium bisulfite 0.06～0.1%

Epichlorohydrin 0.1～0.3%

Synthetic process: First, add appropriate amount of water and sodium acrylate into the reaction vessel, and stir evenly with magnetic stirring. Dissolve and wash the polystyrene foam with a mixed solvent composed of ethyl acetate, toluene, and cyclohexane (volume ratio: about 15:19:5). Mix the above two solutions together, add initiator, dispersant, coupling agent, and crosslinking agent, and shear at high speed for half an hour in a water bath at 30°C. Then react at 70° C. for about three hours under the protection of nitrogen. Finally, it is cured into super absorbent resin at 120°C.

Determination of water absorption: Weigh a certain amount of dry resin and soak it in deionized water until the volume basically does not change. Use a 100-mesh sieve to filter out excess water, then weigh the weight of the resin after absorbing water, and calculate according to the following formula:

Water absorption (g/g) = (resin weight after water absorption (g) - dry resin weight (g)) / dry resin weight (g)

Compared with the prior art, the present invention has following characteristics:

1. The formula is based on waste polystyrene foam and sodium acrylate as the main raw materials. The deionized water absorption rate is 100-1000g/g, and the deionized water absorption capacity is equivalent to that of other pure material-synthesized water-absorbent resins, and some may exceed its water absorption capacity.

2. The synthesis process adopts inverse emulsion polymerization. The product is a binary copolymer with simple process and easy control. The polymerization reaction time is short and the efficiency is high.

3. One of the main synthetic materials in the present invention-waste and old polystyrene foam is the main thing of white pollution, and polystyrene is very easy to fuel. The products that can be synthesized are not fuel-based, and the reaction process is safe and harmless. In this way, these discarded wastes with fire hazards are properly reused, so good economic and environmental benefits can be produced.

Detailed ways

Example 1

Raw material formula (WT%):

Sodium acrylate 90.0%

Polystyrene 6.17%

Span-60 3%

Azobisisobutyronitrile 0.40%

Ammonium persulfate 0.3%

Sodium bisulfite 0.1%

Epichlorohydrin 0.3%

Dissolve polystyrene foam in a mixed solvent of ethyl acetate, toluene, and cyclohexane, add Span-60, and stir in a 40°C water bath for about half an hour. Weigh sodium hydroxide, dissolve it with 10mL deionized water, and neutralize acrylic acid to pH ≈ 7 to prepare a sodium acrylate solution. Stir the neutralized solution at a high speed of 16,000 rpm with a shear emulsifier, mix it with the aforementioned polystyrene emulsion while stirring, and add azobisisobutyronitrile (dissolved in deionized water), ( NH ₄ ) ₂ S ₂ O ₈ (dissolved with deionized water), NAHSO ₃ 0.024g (dissolved with deionized water), and then added epichlorohydrin dissolved in ethanol, stirred for about 30 minutes, protected by nitrogen, in After reacting at 70°C for 3 hours, the material was discharged, and dried at 120°C to obtain a superabsorbent resin. The measured water absorption rate of the product is 172g/g.

Example 2:

Raw material formula (WT%):

Sodium acrylate 88.2%

Polystyrene 7.94%

Span-60 2.9%

Azobisisobutyronitrile 0.3%

Ammonium persulfate 0.3%

Sodium bisulfite 0.2%

Epichlorohydrin 0.16%

Dissolve polystyrene foam in a mixed solvent of ethyl acetate, toluene, and cyclohexane, add Span-60, and stir in a 40°C water bath for about half an hour. Weigh sodium hydroxide, dissolve it with 10mL deionized water, and neutralize acrylic acid to pH ≈ 7 to prepare a sodium acrylate solution. Stir the neutralized solution at a high speed of 16,000 rpm with a shear emulsifier, mix it with the aforementioned polystyrene emulsion while stirring, and add azobisisobutyronitrile (dissolved in deionized water), ( NH ₄ ) ₂ S ₂ O ₈ (dissolved with deionized water), NaHSO ₃ 0.024g (dissolved with deionized water), and then added epichlorohydrin dissolved in ethanol, stirred for about 30 minutes, protected by nitrogen, in After reacting at 70°C for 3 hours, the material was discharged, and dried at 120°C to obtain a superabsorbent resin. The measured water absorption rate of the product is 230.9g/g.

Example 3:

Raw material formula (WT%):

Sodium acrylate 81.3%

Polystyrene 15.62%

Span-60 1.5%

Azobisisobutyronitrile 0.48%

Ammonium persulfate 0.36%

Sodium bisulfite 0.14%

Epichlorohydrin 0.60%

Dissolve polystyrene foam in a mixed solvent of ethyl acetate, toluene, and cyclohexane, add Span-60, and stir in a 40°C water bath for about half an hour. Weigh sodium hydroxide, dissolve it with 10mL deionized water, and neutralize acrylic acid to pH ≈ 7 to prepare a sodium acrylate solution. Stir the neutralized solution at a high speed of 16,000 rpm with a shear emulsifier, mix it with the aforementioned polystyrene emulsion while stirring, and add azobisisobutyronitrile (dissolved in deionized water), ( NH ₄ ) ₂ S ₂ O ₈ (dissolved with deionized water), NaHSO ₃ 0.024g (dissolved with deionized water), and then added epichlorohydrin dissolved in ethanol, stirred for about 30 minutes, protected by nitrogen, in After reacting at 70°C for 3 hours, the material was discharged, and dried at 120°C to obtain a superabsorbent resin. The measured water absorption of the product is above 1000g/g.

Example 4:

Raw material formula (WT%):

Sodium acrylate 76.64%

Polystyrene 19.8%

Span-60 2.18%

Azobisisobutyronitrile 0.40%

Ammonium persulfate 0.40%

Sodium bisulfite 0.1%

Epichlorohydrin 0.48%

Dissolve polystyrene foam in a mixed solvent of ethyl acetate, toluene, and cyclohexane, add Span-60, and stir in a 40°C water bath for about half an hour. Weigh sodium hydroxide, dissolve it with 10mL deionized water, and neutralize acrylic acid to pH ≈ 7 to prepare a sodium acrylate solution. Stir the neutralized solution at a high speed of 16,000 rpm with a shear emulsifier, mix it with the aforementioned polystyrene emulsion while stirring, and add azobisisobutyronitrile (dissolved in deionized water), ( NH ₄ ) ₂ S ₂ O ₈ (dissolved with deionized water), NaHSO ₃ 0.024g (dissolved with deionized water), and then added epichlorohydrin dissolved in ethanol, stirred for about 30 minutes, protected by nitrogen, in After reacting at 70°C for 3 hours, the material was discharged, and dried at 120°C to obtain a superabsorbent resin. The measured water absorption rate of the product is 217g/g.

Example 5:

Raw material formula (WT%):

Sodium acrylate 67.6%

Polystyrene 28.21%

Span-60 3.0%

Azobisisobutyronitrile 0.36%

Ammonium persulfate 0.35%

Sodium bisulfite 0.15%

Epichlorohydrin 0.33%

Dissolve polystyrene foam in a mixed solvent of ethyl acetate, toluene, and cyclohexane, add Span-60, and stir in a 40°C water bath for about half an hour. Weigh sodium hydroxide, dissolve it with 10mL deionized water, and neutralize acrylic acid to pH ≈ 7 to prepare a sodium acrylate solution. Stir the neutralized solution at a high speed of 16,000 rpm with a shear emulsifier, mix it with the aforementioned polystyrene emulsion while stirring, and add azobisisobutyronitrile (dissolved in deionized water), ( NH ₄ ) ₂ S ₂ O ₈ (dissolved with deionized water), NaHSO ₃ 0.024g (dissolved with deionized water), and then added epichlorohydrin dissolved in ethanol, stirred for about 30 minutes, protected by nitrogen, in After reacting at 70°C for 3 hours, the material was discharged, and dried at 120°C to obtain a superabsorbent resin. The measured water absorption rate of the product is 184.3g/g.

Embodiment 6 is substantially the same as Embodiment 1, but the ratio is as follows:

Sodium acrylate 50.0%

Polystyrene 47%

Span-60 2.18%

Azobisisobutyronitrile 0.07%

Ammonium persulfate 0.09%

Sodium bisulfite 0.15%

Epichlorohydrin 0.1%

Embodiment 7 is substantially the same as Embodiment 1, but the ratio is as follows:

Sodium Acrylate 95.09%

Polystyrene 2.5%

Span-60 2.18%

Azobisisobutyronitrile 0.03%

Ammonium persulfate 0.09%

Sodium bisulfite 0.06%

Epichlorohydrin 0.05%

Embodiment 8 is substantially the same as Embodiment 1, but the ratio is as follows:

Sodium Acrylate 95.5%

Polystyrene 2.5%

Span-60 1.77%

Azobisisobutyronitrile 0.03%

Ammonium persulfate 0.09%

Sodium bisulfite 0.06%

Epichlorohydrin 0.05%

Claims (3)

1. A method for utilizing polystyrene to synthesize superabsorbent resin, the process steps are as follows: Sodium acrylate was dissolved in an appropriate amount of water, Polystyrene was dissolved in a mixed solvent, Mix the above two solutions together, Add initiator, dispersant, coupling agent, crosslinking agent, shear emulsification in water bath, Fully react at 60-80°C under protective atmosphere, Curing into super absorbent resin at 110～130℃; Raw material ratio used in the above technique is (WT%): Sodium acrylate 50～95.5% Polystyrene 2.5～47% Dispersant 1.5～3% Coupling agent 0.07～0.4% Initiator 0.1～0.5% Cross-linking agent 0.05-0.6%. 2. The method of utilizing polystyrene to synthesize superabsorbent resin according to claim 1, characterized in that: said initiator is a combination of ammonium persulfate and sodium bisulfite, or a mixture of hydrogen peroxide and sodium bisulfite combination; the dispersant is: Span-60 or sodium dodecylbenzenesulfonate; the coupling agent is: azobisisobutyronitrile or polyethylene glycol 600; the crosslinking agent is the ethanol solution of epichlorohydrin or glycerin. 3. The method for synthesizing superabsorbent resin by using polystyrene according to claim 1 or 2, characterized in that the specific formula and process are as follows: Raw material (WT%) Sodium acrylate 94.1～50.9% Polystyrene 3.4～45.2% Siban-60 2.18～2.90% Azobisisobutyronitrile 0.03～0.3% Ammonium persulfate 0.09～0.3% Sodium bisulfite 0.06～0.1% Epichlorohydrin 0.1～0.3%, Synthesis process: First, add appropriate amount of water and sodium acrylate to the reaction vessel, stir evenly with a magnetic stirrer, dissolve and wash the polystyrene foam with a mixed solvent composed of ethyl acetate, toluene, and cyclohexane, and mix the above two solutions Mix together, add initiator, dispersant, coupling agent, crosslinking agent, shear at high speed for half an hour in a water bath at 30°C, then react at 70°C for three hours under the protection of nitrogen, and finally cure at 120°C to become a super absorbent Sexual resin.