Instand Adhesive

Three Bond Technical News Issued March, 1991 10 INSTANT ADHESIVE (Cyanoacrylate-based) Introduction Instant Adhesives (cyanoacrylate-based) sets instantly at room temperature, has powerful adhesive strength, has only one easy-to-use component, and contains no dangerous solvents. Development of the adhesive began in 1949 by Alan E. Ardis of Goodrich Corporation in the US. Then in 1959 it was introduced into the market by FB Joyner and GF Hawkins of Eastman Corporation as Eastman 910. Later improvements and modifications of the synthetic method of the major-ingredient monomer were performed by the leading adhesive manufacturers. The Eastman 910 became quite popular for both industrial and home use because of its superior features. This report explains the reaction mechanism and advantages as well as disadvantages of instant adhesives and introduces Three Bond 1700 series products and future trends of instant adhesives. Contents Introduction 1. Reaction mechanism ..............................................................................................................................................................................1 2. Three Bond Instant Adhesives (TB1700 series)..................................................................................................................................1, 2 2-1 Classification of Three Bond 1700 series 2-2 Features of Three Bond 1700 series 3. Advantages and disadvantages of Instant Adhesives.............................................................................................................................2 4. Major application examples of Instant Adhesives ...................................................................................................................................3 5. Three Bond 1797 Primer for Instant Adhesives for diffcult-to-adhere materials................................................................................3,4,5 5-1 Outline 5-2 Features 5-3 Properties 5-4 Functions 6. Three Bond 1739: Gel type Instant Adhesive .........................................................................................................................................6 6-1 Outline 6-2 Properties and basic performance 6-3 Performance Postscript 1.Reaction Mechanism The setting reaction mechanism for instant adhesive is anion polymerization. It is quick reacting because a substance having anions causes polymerization and setting within seconds. Typical substances which have these anions are water (H·OH), methanol (CH3OH), caustic soda (NaOH), etc. OH is the molecular structure which acts on cyanoacrylate and polymerizes and sets the resin by the process shown in figure below. Where R: Methyl radical (-CH3), ethyl radical (-C2H5)…Alkyl radical, etc. 2.Three Bond Instant Adhesives (TB1700 series) 2-1 Classification of Three Bond 1700 series Purpose For general adhesive use For heat resistance For impact resistance Three Bond 1700 series For carpentry For low odor, low whitening use TB Grade 1701 1702 1703 1741 1743 1745 1747 Viscosity (cP) 3 35 100 2 100 500 2,000 1713 Classification 100 1751 1753 1781 1782 1783 1785B 1786 1787 3 80 3 80 1,000 3 150 1,100 Remarks Methyl cyanoacrylate Adhesion of metal, rubber, and plastics Ethyl cyanoacrylate Adhesion of metal, rubber and plastics Slow-setting type Excellent heat resistance Excellent release strength and impact resistance For adhesion of porous bonded material such as wood 1721 10 1739 Gel Releasing agent 1795 1 For clean, whitened or protruding areas Hardening promoter 1796 1 For hardening thick-coated areas of padded part, etc. Primer for difficult-to-adhere Materials 1797 1 Adhesion of PE and PP is possible with instant adhesives Gel type Low-odor, low whitening property Gel, ideal for ceiling and perpendicular surfaces * Besides the above standard product, special products are available with various viscosity, colors, etc. 1 2-2 Features of Three Bond 1700 series Three Bond 1700 series has the following outstanding features: 1. Adheres instantly. Usually within only 5 seconds to 3 minutes. 2. Easy-to-use; no training required. It is a single component solution therefore no mixing required. Also no pressurizing or heating required. 3. Adheres powerfully at room temperature. 4. Adheres by using a very small quality. Low viscosity and excellent elongation easily spreads to corners. Consumption is half that of other adhesives. 5. The finish of bonds areas remain neat, colorless and transport. 6. Contraction during setting is practically nil. 7. Speeds up assembly time and improves productivity. 3. Advantages and Disadvantages of Instant Adhesives 90% of Instant Adhesives currently used for general purposes is ethyl cyanoacrylate and the rest is methyl cyanoacrylate. The advantages and disadvantages of these two types of instant adhesives are enumerated below. Advantages Disadvantages 1) Instant adhesive property 1) Inferior heat resistance 2) Room temperature setting type 2) Inferior impact resistance 3) One-solution, non-catalyst type 3) Inferior pliability 4) High adhesive strength 4) Only for small clearances 5) Excellent electric insulation 5) Will not adhere a large area in one stroke 6) Excellent chemical resistance 6) lrritating odor and whitening 7) Small consumption 7) Adheres easily to skin; requires careful handling. 8) Careful storage control required Three Bond 1739 Instant Adhesive Gel 2 4. Major Application Examples of Instant Adhesives Usage examples from various industries are shown below Industry Electrical machinery and equipment Automotive Precision machinery and equipment Musical instruments Others Parts Tape recorder pushbutton Iron pushbutton Player pushbutton Rod antenna ornament Capstan Magnetic head Fuse casing Computer TV CRT tube package Rubber cushion for washing machine Plug code cover Dashboard dresser Braid edge Door handle parts Distributor packing Window-frame rubber Cushion absorber Washer nozzle Mud guard Tail lamp edge ornament Camera finder Printed wriring Camera shutter Camera tripod Strain gauge Sawing-machine parts Piano keys Guitar bridge Banjo drum Piano action parts Flute Hume pipe packing rubber Sphygmanometer Rupture disk of fire extinguisher Carrier wheel Rubber mat fastener Injection needle Writing pen Doll Bonded material ABS + chrome metal fittings Duracon + aluminum Zinc + brass ABS + chrome-plating Brass + stainless steel Parmaloy + iron Polyester + polycarbonate Urethane rubber + polyacetal Neoprene + neoprene Neoprene + ABS Neoprene + SBR Neoprene + soft PVC Foam urethane + soft PVC Soft PVC + soft PVC Neoprene + unichrome plating Neoprene + phenol EPT + EPT Neoplene + unichrome-plating Neoprene + ABS Natural rubber + natural rubber Neoprene + chrome-plating Glass + iron ABS + aluminum Stainless + aluminum ABS + aluminum Polymide + iron ABS + SPC copper ABS + aluminum Posewood + urethane coated board ABS + plywood Maple + maple ABS + chrome-plating Synthetic rubber + synthetic rubber Neoprene + neoprene Polyester + synthetic rubber Neoprene + zinc Synthetic rubber + nylon Stainless + PVC Polyacetal + gold-plating Soft PVC + soft PVC 5. Three Bond 1797 Instant Adhesive Primer –For difficult-to-adhere materials Even in the advanced state of present chemistry no adhesive has been yet developed which securely adheres polyethylene, polypropylene and fluorocarbon resin. Bonding these difficult-to-adhere materials requires acid, heat or radiation treatment to the materials to activate the resin. 3 But all these methods are dangerous, require equipment and are very complicated processes to the point of impracticality. We introduce here a primer which has no such disadvantages but helps to securely bond difficult-toadhere materials. 5-1 Outline 5-2 Features Three Bond 1797 is an exclusive use primer to strongly adhere difficult-to-adhere materials such as polypropylene, polyethylene, polyacetal, EPT rubber, etc., then followed by Three Bond 1700 series (instant adhesive). In the past pretreatment for polypropylene, polyethylene, etc. required strong acid alkali and heat for satisfactory adhesion. But the operation was troublesome and time consuming. Further, safeguards necessary to protect against human exposure made it impractical to use. At that time, Three Bond 1797 was developed to make pretreatment easier and improved room temperature adhesion. 1. Three Bond 1797 has excellent adhesion on polypropylene, polyethylene and polyacetal. Also on EPT rubber, polyurethane and soft PVC. 2. Dries quickly at room temperature so assembly can be performed immediately after coating. 3. Shortens set time. 4. There is a Three Bond 1700 series product to meet any instant adhesive need. 5-3 Properties Product Name Three Bond 1797 Item External appearance Light yellow liquid Viscosity 0.85 Specific gravity 0.80 Major ingredient Amine-based promotor 5-4 Functions a. Set Time (Same and different materials) (second) b. Shear Strength Material Polypropylene Polyethylene Polyacetal Material Iron Material Material (kgf/cm2) Polypropylene Polyethylene Polyacetal Iron 45.6* 39.0* 49.6* 28.1 Polyethylene – 33.0 36.5 21.5 Polyacetal – – 47.1 31.2 Iron – – – 130.5 Polypropylene 5 5 5 10 Polypropylene Polyethylene – 5 5 10 Polyacetal – – 5 10 Iron – – – 15 * Material destruction 25°C×24 hr setting c. Setting Time and Shear Strength Time (hour) (kgf/cm2) 1 2 4 8 12 24 72 Polypropylene Polyethylene 25.1 11.1 30.4* 17.0 35.3* 20.0 38.7* 27.2 41.4* 33.0 45.6* 32.5 46.0* 33.0 Polyacetal 28.1 36.2 40.2* 41.5* 45.2* 47.1* 46.2* Material * Material destruction 25°C setting Setting Time and Shear Strength 4 d. Three Bond 1797 After coating standing time and shear strength Time (hour) Material Polypropylene Polyethylene Polyacetal *Material destruction Immediately after coating 0.5 * 1 * 45.6 21.5 47.1* 25°C×24 hour setting (kgf/cm2) 5 * 48.4 31.6 56.7* 49.4 30.0 55.0 24 * 35.2 21.0 34.7 21.3* 10.6 24.8 After coating standing time and shear strength e. Coated quantity and shear strength Distribution method (kgf/cm2) E A B C D 24.1 27.3 37.3* 42.1* 46.0* 16.4 19.8 32.3 39.4 42.1 61.0* 58.2* 25°×24 hour setting 49.4* 45.2* 14.2 Material Polypropylene Polyethylene Polyacetal *Material destruction Coating method A: One time wiping cloth Immersed in Three Bond 1797 B: Two-time wiping cloth Immersed in Three Bond 1797 C: Three-time wiping cloth Immersed in Three Bond 1797 D: Four-time wiping cloth Immersed in Three Bond 1797 E: Dipping in Three Bond 1797 Coated quantity is large f. Heat Resistance Test Shear Strength Test Material Leave standing at 80°C; setting at room temperature (kgf/cm2) Time (hour) 1 4 8 12 24 Polypropylene Polyethylene Polyacetal *Material destruction 42.1* 41.3* 47.6* 52.1* 47.2* 39.1 40.2 42.2* 42.1* 41.3 48.2* 56.1* 25°×24 hour setting 55.3* 48.6* 48.0* Peeling test Material Peeling strength Polypropylene 3.5* Polyethylene 1.4* g. Usage 1. Wipe and clean surfaces with a solvent, etc. 2. Use cloth or a brush immersed in Three Bond 1797; wipe contact surfaces once or twice. After drying, bond the surfaces with Three Bond 1700 series. 3. When bonding difficult-to-adhere materials such as polyethylene and polypropylene to easy-to-adhere materials such as iron and copper, coat the difficult-to-adhere material with adhesive. 5 4. If the coated quantity of Three Bond 1797 is too much or too little, adhesive force drops. 5. The effect of coated Three Bond 1797 lasts for about one hour. 6. Three Bond 1739 Gel-type Instant Adhesives 6-1 Outline 6-2 Properties and Basic Performance Test Items Three Bond 1739 is a new instant adhesive with gel consistency. The performance level of Three Bond 1739 is the same as liquid-type instant adhesives. But its thixotropic property allows use on perpendicular surface and ceiling. When used with a hardening agent, concave surfaces can also be filled. Appearance Colorless transparent liquid Viscosity 23,000 cP Thixotropic ratio 3.5 Specific gravity 1.03 Set time NBR 35 ~ 40 sec. Set time Iron/Iron 30 ~ 35 sec. Shear strength Iron/Iron 180kgf/cm2 6-3 Performance a. Standing time and Adhesive Force (RT: shear strength) Leave standing 1h 2 4 8 16 24 Strength 85 115 143 162 178 180 Setting the Time × adhesive strength b. Shear strength and set time classified by material Material Set time (secon d) Shear strength (kgf/cm ) Iron - Iron 30 ~ 35 180 SUS - SUS 45 ~ 50 150 Aluminum - Aluminum 20 ~ 30 130 Copper - Copper 10 ~ 15 165 c. Purposes 2 Glass - Glass 10 ~ 15 * Hard PVC - Hard PVC 20 ~ 25 80 Polycarbonate - Polycarbonate 20 ~ 25 70 Nylon - Nylon 20 ~ 25 65 Natural rubber - Natural rubber 30 ~ 35 35 ~ 40 35 ~ 40 (2) Bonds and repairs automotive and machine parts (3) Bonds water products (4) For hobby use such as plastic models (5) Fills and bonds if used with setting agent and paper * EPT - EPT To fix parts and lead wires in printed circuit boards * NBR - NBR (1) * * * * * Material destruction 6 Example Of Use Postscript Instant adhesives easily and quickly adhere because of their structure and reactability. At present, they cannot be used for structural (mono-structural) applications because relative to epoxy resin and alkyl resin adhesives instant adhesives have weaker impact and heat resistance. However, by using a new radical in the molecular structure of instant adhesives and by combining with elastomer, future instant adhesives may have these shortcomings resolved and become marketable. Improvements in instant adhesives will permit instructions of new applications in electric and electronic fields with such features as conductive property and improved operational environment with lower odor and lower whitening. These adhesives will become increasingly important in the near feature. Atsushi Okuma Adhesive Research Team, Research Institute 7 Easy, No Waste, Clean Adhesion Instant Adhesive Automatic Coater Even an excellent product cannot achieve excellent results unless the application technique is equally good. To use good products skillfully yields higher productivity, higher quality and lower costs. Three Bond has developed instant adhesive automatic coaters, requiring no special training and are highly praised by users. Fan-flow N100 Insert a tube into a container filled with adhesive and lightly press the pushbutton on the pen shaped nozzle to discharge adhesive. The coater requires no air source and operates only on electricity. Since it is a tube type, it can supply precise quantity continuously. TB Coater S First the adhesive container is placed into the tank then pneumatic pressure feeds the adhesive. Lightly press the pushbutton on the pen shaped nozzle to discharge adhesive. Micro-adjustment of the discharged quantity is easily made. Since there is no error, it prevents wasting adhesive. The coater can be used not only for manual production, but also can be easily installed on-line with proper modifications.