What is the effect of heat sealing temperature on heat seal strength?
The heat sealing temperature has a very important effect on the heat sealing strength. The thickness of the film in the heat sealing layer plays a decisive role in the heat sealing effect.
① When the temperature is relatively low, the heat sealing layer surface is melted, involved in heat sealing film thickness is relatively thin, resulting in lower contact temperature.
② When the temperature is too high, the heat sealing film may be melted or the heat seal layer has the risk of stripping the base layer, resulting in the upper and lower layers of the film involved in heat sealing, which will inevitably lead to decreased heat sealing strength. So we are in the film heat sealing, we must choose the appropriate heat sealing temperature, not too high can not be too low.
The heat sealing time on the heat sealing what effect?
The heat sealing time of the automatic packaging machine or the old bag making machine is determined by the machine speed. In the case of heat sealing temperature and heat sealing pressure, the longer the heat sealing time, the stronger the bonding between the heat sealing layers. However, if the heat sealing time is too long, the composite film heat sealing parts will appear folds, uneven phenomenon, seriously affect the appearance of the product quality.
What is the effect of heat sealing pressure on heat sealing?
In order to ensure the plastic composite flexible packaging heat sealing strength, a certain heat sealing pressure is essential. Therefore, in the heat sealing process requires heat sealing pressure moderate and uniform. If the heat sealing pressure is not enough or uneven, will make the heat sealing parts of the bubble and Weld, resulting in poor heat sealing.If the heat sealing pressure is too large, the heat sealing parts will appear sealing deformation, heat sealing temperature is high, But also squeeze part of the composite material, resulting in heat sealing edge brittle, easy to crack, while leading to heat sealing strength decreased.
What are the reasons for the uneven pressure of the heat seal?
① heat sealing knife deformation. Heat sealing knife is generally made of good heat transfer properties of aluminum or copper, these two kinds of materials are relatively soft material, so the installation of heat sealing knife, if the method of tightening the screw is not correct, will cause heat sealing knife force is not Uniform, after frequent tool change, it caused the heat sealing knife deformation.
② heat sealing knife machining accuracy is low. Heat sealing knife processing accuracy will cause the heat sealing knife surface uneven, so in the heat sealing process, it will cause the heat sealing pressure is not uniform, thus affecting the composite bag heat sealing strength.
③ heat sealing knife surface dirty or injury. Heat sealing knife surface sticky stolen goods or surface bumps, scratches, the same will cause the heat sealing pressure is not uniform, coupled with the melting resin sticky heat sealing knife surface is not cleaned in time, will also affect the heat sealing strength.
④ silicone rubber hardness and strength. The quality of the silicone rubber is to ensure that the heat sealing pressure is evenly overweight.
