4.5.1 Polyaddition adhesives
Polyaddition adhesives: Various epoxides
- 2-C expoxides
- 1-C exposides, hot curing
- reactive 1-C epoxy resin hotmelts
Polyaddition adhesives: 2-C epoxides (EP)
General description:
- Solvent-free two-component adhesives (2-C) consisting of a resin (component A) and hardener (component B). The resin and hardener are supplied in separate containers and must be mixed prior to being used.
- Curing at room temperature or at elevated temperature
- Cure to become tthermosets
Physical properties of the non-cured adhesive:
- Liquid to paste-like, depending on the product
Processing properties:
- Manual, semi-automated or fully automated processing
- For preferred equipment contact the adhesive manufacturer
- Processing temperature: room temperature, usually between 15 – 30 °C
- Normal contact pressure
- Adhesive film thickness: 0.1 – 0.2 mm, higher for some applications
- Curing method: on mixing the resin and hardener; at room temperature or with heat input
- Heed the processing time / pot life
- The pot life is limited and describes the maximum processing time of the non-cured adhesive. It is indicated on the technical data sheet.
- Curing times: from a few hours to days at RT; faster with heat input
- Secure until the bonded joint has reached hand strength
- Take relevant measures for health and safety at work and environmental protection (General: see Section 7; Details: see safety data sheet)
Typical properties of the cured adhesives:
- High strength
- In general brittle with low elongation at fracture ; tough-elastic products also available
- The cured adhesive is stable at elevated temperatures (up to ca. 120 °C), for short periods (30 min) stable to 200 °C
- Good resistance to physical influences (e.g. sunlight) and chemical influences (moisture, cleaning agents, chemicals, etc.).
The following 5 steps must be carried out within the pot life :
- Weighing out / dosing
- Mixing
- Application
- Joining
- Securing
Points to heed:
- Heed the mixing ratio
- Mix thoroughly following the instructions of the manufacturer; if possible the use of a static or dynamic mixer is preferred to manual mixing; avoid bubble formation
- The processing time / pot life depend on the ambient temperature, quantity of mixture and the particular adhesive product
- Once the pot life has lapsed, do not use any more of the adhesive and dispose of any unused adhesive in the proper way! Large quantities of mixed adhesive can spontaneously combust.
- Once the pot life has lapsed, the position of the bonded substrates may not be further altered
- Heed the curing time
When curing with heat the following points must be heeded:
- Ensure the substrates have adequate thermal stability
- Take into account the heating-up time and cooling-down time for the substrates; this time must be added to the curing time for the adhesive
- The heating temperature refers to the temperature in the joint
- Stress can develop in the joint on heating and cooling
If you have questions about the product then see the technical data sheet or contact the adhesive manufacturer
Polyaddition adhesives: 1-C epoxides (EP)
General description:
- Solvent-free one-component adhesive (1-C)
- Curing at elevated temperatures
- Cure to become thermosets
Physical properties of the non-cured adhesive:
- Consistency: liquid to paste-like
- As film or web: solid
Processing:
- Manual, semi-automated or fully automated processing
- For preferred equipment contact the adhesive manufacturer
- Processing temperature: room temperature, usually between 15 – 30 °C
- Normal contact pressure
- Adhesive film thickness: in general 0.1 – 0.2 mm
- Curing via heat
- Curing conditions: a few minutes to a few hours at 100 – 250 °C depending on the product
- Secure in position during the entire oven process
- Some products suitable for bonding oiled metal sheets (a specific oil in certain quantities)
- Take relevant measures for health and safety at work and environmental protection (General: see Section 7; Details: see safety data sheet)
Typical properties of the cured adhesives:
- High strength
- In general brittle with low elongation at fracture; tough-elastic products also available
- Can also be used (cured adhesive) at elevated temperatures; some products can be used at up to ca. 220 °C
- Very good resistance to physical influences (e.g. UV light) and chemical influences (e.g. moisture, cleaning agents, chemicals, etc.)
Points to heed:
- Check the thermal stability of the substrates prior to curing (in an oven)
- Take into account the heating-up time and cooling-down time for the substrates; this time must be added to the curing time for the adhesive
- The heating temperature refers to the temperature in the joint
- Stress can develop in the joint on heating and cooling
- Only remove the positioning device after reaching hand strength
If you have questions about the product then see the technical data sheet or contact the adhesive manufacturer
Polyaddition adhesives: Reactive epoxy hotmelts
General description:
- Solvent-free one-component adhesive (1-C)
- Dual solidification mechanism involving physical hardening on cooling and post-crosslinking on subsequent heating
- Cure to become thermosets
Physical properties of the non-cured adhesive:
- Consistency: liquid to paste-like
Processing:
- Manual, semi-automated or fully automated processing
- For preferred equipment contact the adhesive manufacturer
- Application at high temperatures; hand strength reached on cooling provides suitable positional integrity and resistance to washing out for subsequent process steps (e.g. coating/lacquering).
- Final curing at high temperature; higher than used for application of the adhesive
- Normal contact pressure
- Adhesive film thickness: in general 0.1 – 2 mm
- Secure in position during the entire oven process
- Special products suitable for bonding oiled metal sheets
- Take relevant measures for health and safety at work and environmental protection (General: see Section 7; Details: see safety data sheet)
Typical properties of the cured adhesives:
- High strength
- In general brittle with low elongation at fracture; tough-elastic products also available
- Can be used at elevated temperatures up to 100 °C
- Good resistance to physical influences (e. g. UV light) and chemical influences (e. g. moisture, cleaning agents, chemicals, etc.)
Processing a reactive 1-C epoxide hotmelt
Points to heed:
- Check the thermal stability of the substrates prior to curing (in an oven)
- Take into account the heating-up time and cooling-down time for the substrates; this time must be added to the curing time for the adhesive
→ Take special care with thick substrates - The heating temperature refers to the temperature in the joint
→ Take special care with thick substrates - Stress can develop in the joint on heating and cooling
If you have questions about the product then see the technical data sheet or contact the adhesive manufacturer
- 2-C polyurethanes
- 1-C-polyurethanes, moisture curing
- Reactive 1-C polyurethane hotmelts
- 1-C polyurethane, hot curing
Polyaddition adhesives: 2-C polyurethanes (PUR)
General description:
- Solvent-free two-component adhesives (2-C) consisting of a resin (component A) and hardener (component B). The resin and hardener are supplied in separate containers and must be mixed prior to being used.
- Curing at room temperature or at elevated temperature
- Depending on the adhesive, the cured product is a thermoset or elasomer
Physical properties of the non-cured adhesive:
- Usually paste-like or solid; in some cases thixotropic properties
Processing properties:
- Manual, semi-automated or fully automated processing
- For preferred equipment contact the adhesive manufacturer
- Processing at room temperature
- Adhesive film thickness: usually: 5 – 25 mm; sometimes less
- For very firm products, hardly any contact pressure is necessary; securing the components against one another suffices
- Curing method: on mixing the resin and hardener; at room temperature or with heat input
- Heed the processing time / pot life
- The pot life is limited and describes the maximum processing time of the non-cured adhesive. It is indicated on the technical data sheet.
- Curing times: from a few hours to days at RT
- Acceleration with heat
- Secure in position until the bonded joint has reached hand strength
- Take relevant measures for health and safety at work and environmental protection (General: see Section 7; Details: see safety data sheet)
Typical properties of the cured adhesives:
- Flexible-elastic to tough-elastic, average elongation at fracture
- Medium to high strength
- Use at temperatures from -40 °C to ca. 110 °C
- In some cases, adhesion without a primer is problematic
- Sensitive to UV radiation
- Repair-bonding on open bead possible
- Can be coated/lacquered in the cured state
- Lower resistance to physical and chemical loads than epoxides
Points to heed:
- The hardener and resin are sensitive to moisture; minimise contact with humid air
- Heed the mixing ratio
- Mix thoroughly following the instructions of the manufacturer; if possible the use of a static or dynamic mixer is preferred to manual mixing; avoid bubble formation
- The processing time / pot life depend on the ambient temperature, quantity of mixture and the particular adhesive product
- A primer layer may be necessary, depending on the surface. Apply a thin, even layer. Immediately close the bottle/container after use.
- Once the pot life has lapsed, do not use any more of the adhesive and dispose of any unused adhesive in the proper way!
- Once the pot life has lapsed, the position of the bonded substrates may not be further altered
If you have questions about the product then see the technical data sheet or contact the adhesive manufacturer
Polyaddition adhesives: 1-C moisture curing polyurethanes
General description:
- One-component adhesive (1-C)
- Curing via air humidity
- Cure to become elastomers
Physical properties of the non-cured adhesive:
- Paste-like or solid, depending on the product; in some cases thixotropic properties
Processing properties:
- Manual, semi-automated or fully automated processing
- For preferred equipment contact the adhesive manufacturer
- Processing temperature: room temperature
- Normal contact pressure; for very firm adhesives: no positioning/securing necessary
- Adhesive film thickness: in general 5 – 25 mm
- Curing method: at room temperature with air humidity (40 – 80 % rel. humidity)
- Curing from outside to inside
- Heed the skinning time!
- The skinning time is the processing time of the non-cured adhesive
- Curing time: several mm in the first 24 hours, then slower; depends on the available humidity/moisture
- Secure until the bonded joint has reached hand strength
- Certain products allow accelerated and uniform curing via the introduction of moisture (booster systems)
- Take relevant measures for health and safety at work and environmental protection (General: see Section 7; Details: see safety data sheet)
Typical properties of the cured adhesives:
- Flexible-elastic, medium to high elongation at fracture
- Medium strength
- Use at temperatures from -40 °C to max. +100 °C
- In some cases, adhesion without a primer is problematic
- Sensitive to UV radiation
- Repair-bonding on open bead possible
- Can be coated/lacquered in the cured state
- Lower resistance to physical and chemical loads than epoxides
Relative humidity
Water content of air in g per kg dry air [g/kg] at standard pressure (1013 hPa)
Curing of moisture curing polyurethanes
Arrangement of adhesive beads on moisture-impermeable substrates
Air circulation possible after joining
Air circulation not possible after joining → No curing of the inner adhesive beads!
Points to heed:
- Heed the required humidity limit at the workplace when processing the adhesives (see the technical data sheet)
- Usually process in combination with a primer
- Once the processing time / skinning time has lapsed, do not further process any more of the adhesive and dispose of any unused adhesive in the proper way!
- Once the processing time / skinning time has lapsed, the position of the bonded substrates may not be further altered
If you have questions about the product then see the technical data sheet or contact the adhesive manufacturer
Polyaddition adhesives: Reactive PUR hotmelts
General description:
- Solvent-free one-component adhesive (1-C)
- Dual solidification mechanism involving physical hardening on cooling and post-crosslinking via air humidity
Physical properties of the non-cured adhesive:
- Paste-like or solid, depending on the product; in some cases thixotropic properties
Processing properties:
- Manual, semi-automated or fully automated processing
- For preferred equipment contact the adhesive manufacturer
- Processing temperature: room temperature
- Normal contact pressure; for very firm adhesives no positioning/securing necessary
- Adhesive film thickness: usually: 5 – 25 mm; sometimes less
- Application at high temperatures (50 – 100 °C) as a melt; hand strength reached on cooling provides suitable positional integrity and resistance to washing out for subsequent processing steps (e.g. coating/lacquering)
- Final curing via air humidity (40 – 70 % rel. humidity); several mm/day
- Take relevant measures for health and safety at work and environmental protection (General: see Section 7; Details: see safety data sheet
Processing a reactive 1-C polyurethane hotmelt
Typical properties of the cured adhesives:
- Flexible-elastic, medium to high elongation at fracture
- Medium strength
- Use at temperatures from -40 °C to max. +100 °C
- Sensitive to UV radiation
- Repair-bonding on open bead possible
- Can be coated/lacquered in the cured state
- Lower resistance to physical and chemical loads than epoxides
Points to heed:
- Post-crosslinking via humidity (moisture)
- Heed the air humidity limit for post-crosslinking (see technical data sheet)
If you have questions about the product then see the technical data sheet or contact the adhesive manufacturer
Polyaddition adhesives: 1-C polyurethanes, hot curing
General description:
- Solvent-free one-component adhesive (1-C)
- Curing via heat
- Cure to become elastomers
Physical properties of the non-cured adhesive:
- Paste-like or solid, depending on the product; in some cases thixotropic properties
Processing properties:
- Manual, semi-automated or fully automated processing
- For preferred equipment contact the adhesive manufacturer
- Processing temperature: room temperature
- Normal contact pressure
- Adhesive film thickness: usually: 5 – 25 mm; sometimes less
- Curing: several minutes to hours at 100 – 200 °C
- Uniform curing
- Secure in position during the entire oven process; in some cases no securing necessary for very firm systems
- Take relevant measures for health and safety at work and environmental protection (General: see Section 7; Details: see safety data sheet)
Typical properties of the cured adhesives:
- Flexible-elastic to tough-elastic
- Medium strength
- Use at temperatures from -40 °C to max. +100 °C
- Sensitive to UV radiation
- Can be lacquered/painted
Points to heed:
- Check the thermal stability of the substrates prior to curing (in an oven)
- Take into account the heating-up time and cooling-down time for the substrates; this time must be added to the curing time for the adhesive
→ Take special care with thick substrates - The heating temperature refers to the temperature in the joint
→ Take special care with thick substrates - Stress can develop in the joint on heating and cooling
If you have questions about the product then see the technical data sheet or contact the adhesive manufacturer
Polyaddition adhesives: Hot curing natural rubbers
General description:
- Solvent-free one-component adhesive (1-C)
- Curing via heat
- Cure to become elastomers
Physical properties of the non-cured adhesive:
- Very paste-like to solid
Processing:
- In general apply with robots
- For preferred equipment contact the adhesive manufacturer
- Processing temperature: room temperature
- Adhesive film thickness: usually 0.2 – 5 mm
- Normal contact pressure
- Curing in the e-coat oven at 150 – 200 °C via vulcanisation of the resin by the hardener (sulphur)
- Secure in position during the entire oven process
- Take relevant measures for health and safety at work and environmental protection (General: see Section 7; Details: see safety data sheet)
Typical properties of the cured adhesive:
- Flexible-elastic to tough-elastic, also available as foam
- Medium strength
- Medium to high elongation at fracture
- Can be used from -30 °C to +90 °C
- High fatigue strength
- Good stability to moisture
- Adhesion to many different materials and to oiled metal sheets
Points to heed:
- Check robot application, e.g. with templates
- Check the thermal stability of the substrates prior to curing (in an oven)
- Take into account the heating-up time and cooling-down time for the substrates; this time must be added to the curing time for the adhesive
→ Take special care with thick substrates - The heating temperature refers to the temperature in the joint
→ Take special care with thick substrates - Stress can develop in the joint on heating and cooling
If you have questions about the product then see the technical data sheet or contact the adhesive manufacturer