Polyurethane paper plastic compound

Paper-plastic composite refers to the combination of printing color printing paper and plastic film to form a paper-plastic film. The plastic film used is a polypropylene film or a polyester film, and a general adhesive is difficult to bond, and a satisfactory result can be obtained with a polyurethane adhesive. General-purpose polyurethane adhesives are used in paper-plastic composite films with high quality requirements and can be used in hot and humid environments. Now we will introduce the preparation method for the paper-plastic composite polyurethane adhesive prepared by using TDI modified castor oil as the main agent (A component) and TMP-TDI adduct as the curing agent (Part B).

1. Preparation method

(1) Castor oil dehydration and finely-divided castor oil was dehydrated under vacuum at 12°C and 1.3 kPa for 2 hours, and the water content was determined to be 0.08%.

(2) castor oil-TDI modified material (main agent) Add 61.5kg of dehydrated castor oil to the reactor, start the stirrer, raise the temperature to 45-50°C, and slowly add 9.4kg of TDI (80/ 20) After reacting at 70° C. for 3 hours, 23 kg of ethyl acetate and 34.5 kg of toluene are added, and the mixture is stirred for half an hour before discharging to obtain a castor oil-TDI modification (main agent or a component). The appearance is light yellow and transparent. The viscous liquid has a viscosity of 65-100 mPa·s (25°C) and a solids content of 55%.

(3) TMP-TDI adduct (curing agent) 35.3 kg of ethyl acetate (less than 0.1% of moisture) and 52.2 kg of TDI (80/20) are added to the reactor, the stirrer is turned on, and the temperature is raised to 50°C. , Slowly add 13.4kg of pre-melted trimethylolpropane (TMP), control the reaction temperature at 70°C, discharge at 70-75°C for 1h, and prepare the TMP-TDI adduct (curing agent or B Component), the appearance of light yellow or colorless transparent viscous liquid, viscosity 1000-1500mdPa · s (25 °C), solid content of 65%.

2. Adhesive formulation and performance

When the adhesive is used, it is prepared according to Part A: Part B = 4:1 (parts by mass), and then diluted with 3 parts by mass of toluene of the glue (working glue concentration is 15%). Paper-polypropylene film peel strength> 4N/cm.

Paper-plastic composite film is mainly used for book covers, packaging cartons, art calendars, maps, etc. The products are exquisite in appearance, but also have the advantages of waterproof, abrasion resistance, etc., and are widely used by users.

Reprinted from: 21st Century Fine Chemicals Network