Scope of Application Alcohol-soluble adhesives are widely used in pretreated OPP, CPE, CPP, PA, PT, AL, vacuum aluminum coating, paper and other substrates.
Advantages of Alcohol-soluble Polyurethane Adhesives 1. In the main agent, they are free of isocyanide (-NCO) and highly toxic free TDI, so they are non-toxic and safe during the production and application of composite membranes. . Nowadays, alcohol-soluble polyurethane adhesives commonly used in the country contain high-NCO and free TDI in the curing agent, which greatly damages the health of workers in the production process. In addition, over time, TDI may be hydrolyzed, releasing a type of cancer TDA. Ethyl acetate is also extremely irritant, harmful to human lungs and liver, and contaminates the environmental coconut oil.
2. Alcohol-soluble adhesive An inexpensive industrial alcohol, n-propanol, and isopropanol are used as solvents, which have good hygienic performance, low production cost, harmless to workers, and no pollution to the environment.
3, alcohol-soluble adhesives are not afraid of water, are not sensitive to the wet climate, especially in the rainy season in the south, can also be produced without quality accidents.
4. The alcohol-soluble adhesive has good initial tackiness, and the composite film has good transparency and can react well to the package contents.
5. The adaptability of the alcohol-soluble adhesive to the machine is very good and can be directly produced without equipment modification.
6, Alcohol-soluble adhesive and alcohol-soluble polyurethane printing ink can be used in combination to achieve excellent composite strength, because the alcohol-soluble polyurethane printing ink inevitably has residual solvent of ethanol, ethanol and ester-soluble bond The curing agent of the agent undergoes a chemical reaction, namely, -OH and -NCO reaction, thereby affecting the curing of the alcohol-soluble adhesive and reducing the composite fastness.
7. The residual solvent of the alcohol-soluble binder is very low, even if there is a certain residue, it is also the residue of ethanol, and its toxicity is very low, about 1/3 of ethyl ester.
Handling Precautions 1. Ketones or solvents containing ketone impurities cannot be used. Ketones in alcohols cannot exceed the standard, because the presence of ketones can cause odor in the composite membrane.
2. If the equipment is previously using an alcohol-soluble binder, the doctor frame, glue tank, anilox roller, and circulation pump should be cleaned before using the alcohol-soluble binder to avoid contaminating the adhesive and blocking the network cable. Roller.
3, the deployment of a good glue is best used the same day, if the remaining residual liquid is too much, can be diluted several times after the dilution of the diluent, the next day of production, can be used as a diluent, each time a small number of points plus new After the glue is used, if the glue is white or thickened, it cannot be used.
4. Unopened adhesives should be stored in a cool, dry environment with a storage period of 12 months.
5, dry composite processing film must be corona treatment, so that the surface tension of 38 dyne or more, in order to achieve the desired results.
6. The size of the sizing depends on the type and working density of the cable roller. The recommended use concentration is 20%-30%.
The use of technology 1. The order of the rubber: the main agent is processed first, then the solvent is added, the mixture is evenly mixed, then the curing agent is added, and the mixture is evenly mixed, and the mixture can be used.
2. Coated amount: When dry compounding, the working solid content is 20%-30%, dry glue amount is 2g/m2-4g/m2
The amount of drying should be based on the weight of the contents of the package, and the amount of coating should be increased if the viscosity and strength requirements are high.
3. Composite temperature: The temperature of the composite roll is generally about 60-70°C. The composite temperature of the film susceptible to temperature should be about 50-60°C lower, and the temperature of the aluminum foil is 70°C.
4. Drying temperature: In order to ensure that the coated viscous agent is fully dried, the machine speed, air volume and temperature must be matched. If the drying device is divided into three sections, it should be from the entrance to the exit of the film, and the temperature gradient is 50- 60°C, 70°C, 80°C.
5. Curing: Alcohol-soluble adhesives have a certain initial tackiness after reconstitution and processing. They can be heated at 40-50° C. for aging for 12 hours, and can be slit or bagged and can be completely cured in 2 days.
Alcohol-soluble binders have certain requirements for solvents. The standards and test methods are as follows:
1, standard
Methanol (%) ≤ 0.030
0.16 Non-volatile matter (%) ≤ 0.0025 Fusel oil (%) ≤ 0.010 Sulfuric acid test, points ≤ 100 Oxidation test, points ≥ 15 Acid (acetic acid) 0.0020
Use cautions:
(1) Aldehydes can not be exceeded, and can't be used in excess of standards because aldehydes will affect the curing of adhesives. The composite film became sticky after curing.
(2) Sensory detection method: It is colorless, clear, transparent, with no visible insoluble impurities. It quickly volatilizes completely after the handkerchief, and is not sticky. There is no smell or odor except the smell of alcohol.
2, timing detection method:
A. Determination of ethanol content:
(1) Principle: At a certain temperature, an alcohol meter made with a certain functional relationship between ethanol content and its density is used for the determination.
(2) Equipment and equipment:
Alcohol meter: 94.0% to 98.0% (V/V) division value 0.1%.
Thermometer: 0 ~ 50 °C mercury thermometer, scaled value of 0.1%.
Jacketed measuring cylinder: 500ml
Super constant water bath: temperature controlled at 20±0.1°C
(3) Analysis procedure Place the sample in a clean and dry jacketed measuring cylinder and place it into the sample. The lower end of the sample should be more than 2cm away from the bottom of the cylinder. When the temperature of the sample reaches 20°C±0.1, the alcohol meter is pressed down to 2 When the scale is to be left to stand, the scale of the lower edge of the meniscus of the alcohol meter is read, which is the ethanol content at 20°C.
(4) The results indicate that the ethanol content was directly read from the alcohol meter.
Take the arithmetic average of the results of two parallel measurements as the measurement result.
B. Determination of acid content:
(1) Principle: Using phenolphthalein as an indicator, titrate the acid in the sample with NaOH.
(2) Reagents and solutions:
1 CO2 free water 2NaOH standard solution: 0.1mol/L
(3) Phenolphthalein: 5g/L
Instrument: Burette: 1ml graduation value 0.02ml
Pipette: 100ml
(4) Analysis steps:
Measure 100ml of water in a conical flask, add 2-3 drops of cesium, drop it to pink with NaOH standard solution, keep it for 15 seconds without discoloration, pipette 100ml sample into the above solution, use NaOH standard The solution dropped to light pink and did not fade for 15 seconds.
(5) Calculation:
The percentage of acid X1 is calculated as follows:
X1=(0.06005×V·C/Ï·100)×100
C-NaOH standard solution concentration V-consumption NaOH standard solution volume 0.06005- equivalent to 1.00 ml NaOH standard solution (CNaOH=0.1000 mol/L) mass of acetic acid expressed in grams Ï-20°C density of the sample g/cm3
C, aldehyde content determination:
(1) Principle: The magenta-sulfuric acid solution reacts with the aldehyde in the sample to generate a reddish violet dye, and is measured at a wavelength of 560 nm at the spectrophotometer.
(2) Reagents and solutions:
1 aldehyde-free ethanol 2 magenta - sulfite solution take 1500ml water placed in a 3000ml flask, add 4.5 ± 0.001g basic fuchsin (C19H18N2CL) stirring to dissolve, add 96.00 ± 0.05g sodium metabisulfite (Na2S2O5) mix, place 5 -10 minutes and then add 40ml 16% (m/n) sulfuric acid solution and mix, cover and stand for 12 hours, (if color, activated carbon decolorization) in a cool place.
3 acetaldehyde standard solution preparation:
Solution A:
Weigh 0.693g of acetaldehyde ammonia, weigh 0.001g and place it in a 500ml volumetric flask, dissolve with aldehyde-free ethanol, dilute to the mark, and mix to obtain 0.001g/ml acetaldehyde standard solution.
Such as acetaldehyde ammonia color, can be purified as follows:
A solution of 5 g of acetaldehyde in ammonia is added to a small volume of anhydrous ethanol, approximately 2 volumes of dry ether are added to precipitate the solution, and the solution is filtered through a Buchner funnel. The precipitate is washed thoroughly with ether and then transferred to a concentrated sulfuric acid vacuum desiccator. -4 hours.
Solution B:
Aspirate 100 ml of solution A in a 250 ml volumetric flask and scale with aldehyde-free ethanol to obtain a 0.0004 g/ml acetaldehyde standard solution.
Solution C:
Pipette 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, and 8.0 ml of solution B into 8 100 ml volumetric flasks, dilute to scale with aldehyde-free ethanol to obtain 0.0005%, 0.001%, 0.0015%, 0.002% , 0.0025%, 0.003%, 0.0035% acetaldehyde standard solution.
(3) Instruments: pipette: 5,10 ml fractionation is 0.1 ml;
Colorimetric tube: 25ml
Volumetric flask: 100ml
Spectrophotometer:
(4) Analytical procedure: Pipette 3 ml each of the sample and standard solution C into the colorimetric tube, release 10 ml of water, add 4 ml of magenta-sulfurous acid solution, cover the mixture, and mix for 25 minutes. Use a 2 cm ratio. The dish was measured with water at a wavelength of 560 nm and the absorbance A was measured with a spectrophotometer.