**5.4 Tensile shear strength vs. environmental condition**

Testing has been conducted to measure and compare using test specimen the tensile shear strength at different high temperature (85°C) and high humidity (85% RH) for max 1000 h aging time. Specimen was glass and ABS, together with painted ABS substrates. After adhesive dispensing and glass part assembly, it was put into environment chamber immediately. As shown in **Figures 25** and **26**, we can see that as the aging time progresses, the tensile shear strength difference is widened explaining that the PUR HM adhesive increases as time goes by, while 1 component silicone has no curing within 1 h of aging and maintains a lower strength than polyurethane hot melt adhesive; especially for painted ABS substrate, it shows a


**Table 5.** *Bonding strength vs. loading.*

**Figure 23.** *Chrome-plated + glass bonding.*

**Figure 24.** *ABS + glass bonding.*

sharp decrease of bonding strength at 1000 h. Polyurethane hot melt adhesive shows an immediate certain strength initially due to pure hot melt fixturing function, but as time goes by, due to the chemical reaction, the adhesion strength increases to a higher reliable level. The assembly of glass to painted ABS shows a higher ultimate strength than the assembly of glass to ABS.

#### **Figure 25.**

therefore, it has a de-bonding even after 10 min of curing time. This explains more compact and process efficient assembly process with less time and less manpower for polyurethane hot melt adhesive compared to 1 component silicone solution.

Testing has been done to measure the bonding strength, failure mode per different loading after a high temperature environmental condition (70°C for 1 week), and a high humidity condition (50°C/95%RH for 1 week). As shown in **Table 5**, polyurethane hot melt adhesive solution has no de-bonding when the weight loading of 25, 50, and 100 kg was placed on top of glass part; then, 3 times of 100 kg impact was applied to the glass part and the bond line remained intact between glass and mating substrates but the glass in the diddle was shattered instead. **Figures 23** and **24** explain the intact bond line area of both chrome-plated + glass

Testing has been conducted to measure and compare using test specimen the tensile shear strength at different high temperature (85°C) and high humidity (85% RH) for max 1000 h aging time. Specimen was glass and ABS, together with painted ABS substrates. After adhesive dispensing and glass part assembly, it was put into environment chamber immediately. As shown in **Figures 25** and **26**, we can see that as the aging time progresses, the tensile shear strength difference is widened explaining that the PUR HM adhesive increases as time goes by, while 1 component silicone has no curing within 1 h of aging and maintains a lower strength than polyurethane hot melt adhesive; especially for painted ABS substrate, it shows a

**Aging condition 25 kg weight 50 kg weight 100 kg weight** 70°C 1 week No de-bonding No de-bonding No de-bonding 50 °C 95%RH 1 week No de-bonding No de-bonding No de-bonding

**5.3 Bonding strength vs. environmental condition 1 vs. loading**

**5.4 Tensile shear strength vs. environmental condition**

and ABS + glass bonding.

*Advanced Functional Materials*

**Table 5.**

**Figure 23.**

**Figure 24.** *ABS + glass bonding.*

**308**

*Bonding strength vs. loading.*

*Chrome-plated + glass bonding.*

*Tensile shear strength comparison for glass + ABS.*

**Figure 26.** *Tensile shear strength comparison for glass + painted ABS.*

#### **Figure 27.**

*Gap change at different corners vs. environment conditions.*

### **5.5 Bond line vs. environmental condition 3**

Testing has been done to measure the difference of bond line gap change before and after three different environmental conditions. As mentioned in the refrigerator section, polyurethane hot melt adhesive provides an excellent environment resistance. As shown in **Figure 27**, polyurethane hot melt adhesive exhibits a minimal gap change before and after three different environmental conditions. Specimens #1, #2, and #3 are the conditions of thermal cycle 4 h at 70°C/65%RH to 4 h at �30°C (10 cycles); specimens #4, #5, and #6 are on the condition of high temperature 168 h at 70°C; and specimens #7 and #8 are on the condition of high humidity 168 h at 40°C/95%RH. The gap change at 4 corner area of top cover that has a biggest tendency of gap change was measured.

safety too; it also increases the quality of the assembly as the time to be exposed to the ambient environment contamination such as dirt sticking to silicone surface is minimal due to its fast cure while the 1 component silicone solution is difficult to avoid such appearance and contamination quality issue. **Figure 28** explains the fast fixture time of 2 component silicone within a short time (3 min) compared to 1 component silicone that takes 24 h to achieve the same initial strength. Using 2 component silicone solution, within a few minutes, the assembly can moves to the

Testing has been carried out to measure a tensile shear strength to compare the bonding reliability before and after aging condition between 2 component silicone solution and tape solution as some manufacturers use tape only without 1 component silicone. Substrate was a ink printed glass and ABS or polycarbonate. Testing conditions were at room temperature (23°C), low temperature (40°C for 2 h), high temperature (80°C for 2 h), high temperature and high humidity (80°C for 8 h, 40° C for 8 h as 1 cycle for 27 days) and thermal cycle tests (60°C for 4 h to 30°C for 4 h as 1 cycle for 27 days). As shown in **Figures 29**, 2 component silicone solution has at least 3–5 times higher bonding strength for all aging conditions compared to tape solution. Overall, it is very clear that as for environmental durability, 2 component

As reviewed and compared for three appliances on the above such as refrigerator, washing machine, and microwave, those new technologies such as polyurethane hot melt and 2 component silicone solution can help appliance manufacturers open their eyes much wider for new assembly solutions that can provide overall assembly process efficiency such as faster work in process (WIP), automated assembly that can reduce overall man powers and reduce assembly space, increase assembly reliability such as higher bonding strength after severe environment conditions and ultimately the assembly can receive a better reputation and high end

This work was supported by various lab engineers who have devoted their time for various and lengthy testing. Great thanks to them for their professional and

silicone solution provides a far more reliable bonding than tape solution.

next process [3].

**Figure 29.**

**7. Conclusions**

image at the market place.

**Acknowledgements**

**311**

**6.2 Tensile shear strength vs. aging condition**

*Tensile shear strength vs. different aging conditions.*

*DOI: http://dx.doi.org/10.5772/intechopen.90515*

*Global Trend of Glass Bonding for Appliance Industry Assemblies*

#### **6. Microwave**

In this section, we are going to compare 2 component silicone vs. 1 component silicone in terms of process efficiency. Application is for bonding of glass plate to plastic case in the external three front door [3].

#### **6.1 Production efficiency**

The 1 component silicone solution is to apply a primer onto plastic case by 0.5 operator (15 s) ! place double-sided tape on a few location by 0.5 operator for instant fixing (20 s) ! silicone is dispensed by dispenser (15 s) ! glass plate is placed on the plastic case and pressed (5 s) ! clip and tape are used to fix the bonded assembly by one operator (20 s) ! fixed assemblies go through a heating conveyor ! after conveyor, tapes and clips are removed by 0.5 operators (15 s) ! the assembly stacked onto rack by 0.5 operator (10 s) ! rack is placed in the corner of plant for 24 h curing ! cured assembly transfer to next process.

The 2 component silicone solution is to apply primer by machine (10 s) ! primer drying by fan (10 s) ! adhesive dispensing by machine (15 s) ! glass plate placed onto plastic case by machine (15 s) ! glass plate pressing by machine (45 s) ! initial fixture of assembly achieved and transfer to next process.

The 1 component silicone solution takes three operators and many steps, and especially takes minimum 1 day for silicone curing before transferring to next process, while the 2 component silicone solution requires no operator and its processing time from primer application to initial fixture takes only 3 min which is a dramatic improvement of its assembly efficiency, and this solution required a minimal space for the whole process which is another benefit; it requires no heating conveyor, thus eliminates the concern on extra energy consumption and is operator

**Figure 28.** *Fixture time between 2C silicone and 1C silicone.*

*Global Trend of Glass Bonding for Appliance Industry Assemblies DOI: http://dx.doi.org/10.5772/intechopen.90515*

#### **Figure 29.**

**5.5 Bond line vs. environmental condition 3**

*Advanced Functional Materials*

biggest tendency of gap change was measured.

plastic case in the external three front door [3].

**6. Microwave**

**Figure 28.**

**310**

*Fixture time between 2C silicone and 1C silicone.*

**6.1 Production efficiency**

Testing has been done to measure the difference of bond line gap change before and after three different environmental conditions. As mentioned in the refrigerator section, polyurethane hot melt adhesive provides an excellent environment resistance. As shown in **Figure 27**, polyurethane hot melt adhesive exhibits a minimal gap change before and after three different environmental conditions. Specimens #1, #2, and #3 are the conditions of thermal cycle 4 h at 70°C/65%RH to 4 h at �30°C (10 cycles); specimens #4, #5, and #6 are on the condition of high temperature 168 h at 70°C; and specimens #7 and #8 are on the condition of high humidity 168 h at 40°C/95%RH. The gap change at 4 corner area of top cover that has a

In this section, we are going to compare 2 component silicone vs. 1 component silicone in terms of process efficiency. Application is for bonding of glass plate to

The 1 component silicone solution is to apply a primer onto plastic case by 0.5 operator (15 s) ! place double-sided tape on a few location by 0.5 operator for instant fixing (20 s) ! silicone is dispensed by dispenser (15 s) ! glass plate is placed on the plastic case and pressed (5 s) ! clip and tape are used to fix the bonded assembly by one operator (20 s) ! fixed assemblies go through a heating

(15 s) ! the assembly stacked onto rack by 0.5 operator (10 s) ! rack is placed in the corner of plant for 24 h curing ! cured assembly transfer to next process.

The 2 component silicone solution is to apply primer by machine (10 s) ! primer drying by fan (10 s) ! adhesive dispensing by machine (15 s) ! glass plate placed onto plastic case by machine (15 s) ! glass plate pressing by machine (45 s) ! ini-

The 1 component silicone solution takes three operators and many steps, and especially takes minimum 1 day for silicone curing before transferring to next process, while the 2 component silicone solution requires no operator and its processing time from primer application to initial fixture takes only 3 min which is a dramatic improvement of its assembly efficiency, and this solution required a minimal space for the whole process which is another benefit; it requires no heating conveyor, thus eliminates the concern on extra energy consumption and is operator

conveyor ! after conveyor, tapes and clips are removed by 0.5 operators

tial fixture of assembly achieved and transfer to next process.

*Tensile shear strength vs. different aging conditions.*

safety too; it also increases the quality of the assembly as the time to be exposed to the ambient environment contamination such as dirt sticking to silicone surface is minimal due to its fast cure while the 1 component silicone solution is difficult to avoid such appearance and contamination quality issue. **Figure 28** explains the fast fixture time of 2 component silicone within a short time (3 min) compared to 1 component silicone that takes 24 h to achieve the same initial strength. Using 2 component silicone solution, within a few minutes, the assembly can moves to the next process [3].

#### **6.2 Tensile shear strength vs. aging condition**

Testing has been carried out to measure a tensile shear strength to compare the bonding reliability before and after aging condition between 2 component silicone solution and tape solution as some manufacturers use tape only without 1 component silicone. Substrate was a ink printed glass and ABS or polycarbonate. Testing conditions were at room temperature (23°C), low temperature (40°C for 2 h), high temperature (80°C for 2 h), high temperature and high humidity (80°C for 8 h, 40° C for 8 h as 1 cycle for 27 days) and thermal cycle tests (60°C for 4 h to 30°C for 4 h as 1 cycle for 27 days). As shown in **Figures 29**, 2 component silicone solution has at least 3–5 times higher bonding strength for all aging conditions compared to tape solution. Overall, it is very clear that as for environmental durability, 2 component silicone solution provides a far more reliable bonding than tape solution.

#### **7. Conclusions**

As reviewed and compared for three appliances on the above such as refrigerator, washing machine, and microwave, those new technologies such as polyurethane hot melt and 2 component silicone solution can help appliance manufacturers open their eyes much wider for new assembly solutions that can provide overall assembly process efficiency such as faster work in process (WIP), automated assembly that can reduce overall man powers and reduce assembly space, increase assembly reliability such as higher bonding strength after severe environment conditions and ultimately the assembly can receive a better reputation and high end image at the market place.

#### **Acknowledgements**

This work was supported by various lab engineers who have devoted their time for various and lengthy testing. Great thanks to them for their professional and
