Development of Waste Polystyrene Foam Recycled Adhesive III

Development of 2 PS Modified Adhesive

2.1 Development of Solvent Modified PS Adhesive

2.1.1 Instruments and Drug Instruments: Constant Temperature Water Bath; Electric Stirrer; NDJ-1 Rotating Viscometer; Instron 4467, 4505 Universal Material Testing Machine; Blast Oven; SC-7 Gas Chromatograph (Hydrogen Flame Identifier) ). Drugs: polystyrene foam; epoxy resin (E-51); toluene diisocyanate; azobisisobutyronitrile; ethyl acetate; toluene; talc; amine curing agent.

2.1.2 Principle of experiment

Polystyrene is an amorphous linear non-polar substance that contains a benzene ring in its molecule and has high rigidity and low flexibility. The adhesive force on the surface of the polar material is very weak, and the adhesive directly prepared with polystyrene has insufficient strength and the adhesive layer is brittle and hard. Therefore, it is necessary to modify the PS glue by adding modifiers, and introduce polar groups on the styrene links to increase the flexibility and increase the bonding strength. I chose epoxy resin (E-51) and toluene diisocyanate as modifiers. Toluene diisocyanate first reacts with polystyrene under the action of the initiator azobisisobutyronitrile. The reaction formula is as follows:

(2) Cross-linking reaction of chain radicals with toluene 2,4-diisocyanate

(R stands for benzyl)

Then add epoxy resin, epoxy resin structure contains -OH, isocyanate and epoxy resin can react -OH, the reaction is as follows:

In this way, the isocyanate successively changes the PS and the epoxy resin and causes partial cross-linking between the two.

2.1.3 Preparation of Adhesives

Place the reaction vessel in a constant temperature water bath, install a stir bar, add 100 parts of mixed solvent (ethyl acetate:toluene=4:1), and add 50 parts of washed and dried waste polystyrene foam in batches. Stirring is started, and after all is dissolved, the temperature is gradually raised to 70° C., 0.5 parts of initiator azobisisobutyronitrile, 3 parts of toluene and 2,4-diisocyanate are added, and the reaction takes about 1-1.5 hours under moderate speed stirring. Add 0.5 part of toluene 2,4-diisocyanate, cool down to 50°C, add 10 parts of epoxy resin (6101), continue the reaction for 1 hour, add 10 parts of filler after cooling, and obtain yellowish viscous adhesive Liquid, this glue need to add curing agent.

2.1.4 Test Methods for Various Adhesives

The content of non-volatile matter was measured according to GB/T2793-95 method, the viscosity was measured according to GB/T2794-95 method, and the tensile shear strength was measured according to the method of GB7124. The amount of harmful substances in the adhesive was measured according to the method of GB18583-2001.

2.2 Development of Emulsion PS Modified Adhesive

2.2.1 Instruments and Drugs

Instruments: electric mixer; electric heating sleeve; four-necked flask; spherical reflux condenser; thermometer; dropping funnel; Instron 4467, 4505 general purpose material testing machine; blast oven; SC-7 gas chromatograph; infrared spectrometer.

Pharmaceuticals: Styrofoam; Butyl Acrylate; Vinyl Acetate; Dioctyl Phthalate; Ethyl Acetate; Toluene; Initiator Ammonium Persulfate; Mixed Emulsifier (Sodium Lauryl Sulfate: OP-10 =1:2)

2.2.2 Preparation of water agent PS modified rubber

In a four-necked flask, 50 parts of a mixed solvent (ethyl acetate:toluene:4:1) was added, and 40 parts of washed and dried crushed waste polystyrene foam were added in batches under stirring, and the temperature was gradually raised to 40° C. until completely completed. After dissolving into a transparent viscous liquid, add 1 part of emulsifier, emulsify with stirring for 30 min, add 40 parts of water (distilled or deionized water) and 4 parts of mixed monomer (butyl acrylate: vinyl ester = 1:1) , Warm up to 60°C, increase the stirring speed, emulsify for 30-40min, add part of the initiator (ammonium persulfate 10% solution); When the reaction, there is heat release, the temperature starts to rise automatically, at this time, heating makes the temperature At 75° C., a solution of 12 parts of monomer mixture and 80 parts of water was added dropwise. During the process of adding the mixed monomer aqueous solution, part of the initiator was added at intervals (a total of 1 part initiator). The reaction temperature was reached. Should be controlled between 75-85 °C, after all the addition is completed (about 1.5-2h), the remaining initiators are all added, heated to 90 °C insulation, the solvent to be recovered when the amount of 80-85% of the added amount Stop heating, then cool to 50°C and add two plasticizers o-benzene Acid dioctyl ester, stirred uniformly, to adjust the PH value of about 7, was cooled to room temperature to obtain a white viscous liquid.

2.2.3 Test Method for Various Performance Indexes of PS Modified Emulsion Adhesives

Adhesive non-volatile content was measured according to GB/T2793-95 method. The adhesive's rotational viscosity was measured according to GB/T2794-95 method. Compressive shear strength was measured according to HG/T2727 Appendix B method. Ash content and PH value were measured according to GB11175 method. The determination of harmful substances in adhesives was carried out according to the method of GB18583-2001.

(to be continued)