Multilayer Interlayer Film Gap Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional interlayer films for laminated glass often result in gaps at the ends of the glass sheets when exposed to light or heat, leading to reduced adhesive force and increased yellow index values, affecting the appearance and performance of the laminated glass.
Innovation Solution
An interlayer film with a specific multilayer structure, including a first layer with a polyvinyl acetal resin, a higher plasticizer content, and a hindered amine light stabilizer, along with a second and third layer, is used to prevent gap formation and minimize yellow index increases, enhancing adhesive force and penetration resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional interlayer film is used, then the basic lamination function is achieved, but gaps are generated at the end part when exposed to light and heat
Solution Approach 1:
The patent applies local quality by creating a multilayer structure where the first layer (containing hindered amine light stabilizer and higher plasticizer content) is positioned at the end parts of the interlayer film that are most susceptible to gap formation, while the second and third layers provide overall structural support. This localized enhancement of stabilizer and plasticizer concentration at critical areas prevents gap formation without requiring the entire film to have uniformly enhanced properties.
Solution Approach 2:
The patent employs composite materials by combining polyvinyl acetal resin with hindered amine light stabilizers and plasticizers in a multilayer configuration. The first layer contains a higher plasticizer content (greater than 40 parts by weight per 100 parts resin) compared to the second and third layers (30-40 parts), creating a composite structure that leverages the complementary properties of each layer to prevent gap formation while maintaining overall film integrity.
2Reliability
If a conventional interlayer film is used, then the lamination structure is maintained, but the yellow index value increases at the end part under light exposure
Solution Approach 1:
The patent applies local quality by concentrating hindered amine light stabilizers and plasticizers in the first layer at the end parts of the interlayer film, which are most exposed to light and heat. This localized enhancement provides targeted protection against yellowing at the critical end regions without requiring uniform distribution throughout the entire film, thereby maintaining color stability where it is most needed.
Solution Approach 2:
The patent converts the harmful effect of light and heat exposure into a beneficial outcome by using hindered amine light stabilizers that specifically counteract UV-induced degradation. The plasticizers also contribute by maintaining film flexibility and preventing crack formation that would accelerate yellowing, thereby transforming the challenging environmental conditions into an opportunity to demonstrate the effectiveness of the stabilizer system.
3Strength
If the plasticizer content is increased to prevent gap formation, then adhesive force is improved, but the film structure becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the interlayer film into three distinct layers with different compositions and functions. The first layer contains higher plasticizer content (greater than 40 parts per 100 parts resin) for gap prevention and adhesive enhancement, while the second and third layers contain lower plasticizer content (30-40 parts) for structural support. This segmentation allows each layer to be optimized for its specific function, achieving high adhesive force without requiring the entire film to have uniformly high plasticizer content, thereby managing complexity through functional differentiation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The interlayer film effectively prevents gap formation and suppresses yellow index increases, maintaining the integrity and appearance of laminated glass even under prolonged light exposure and high temperatures, while improving adhesive force and sound insulating properties.
Implementation Method 1
the first layer further includes a hindered amine light stabilizer in which an alkyl group or an alkoxy group is bonded to a nitrogen atom of a piperidine structure
Implementation Method 2
a hindered amine light stabilizer in which an alkyl group or an alkoxy group is bonded to a nitrogen atom of a piperidine structure
Implementation Method 3
the content of the plasticizer included in the first layer relative to 100 parts by weight of the polyvinyl acetal resin included in the first layer is greater than the content of the plasticizer included in the second layer
Data Source
Figure 1~2
AI summary
There is provided an interlayer film for laminated glass in which a gap is difficult to be generated at the end part of a sheet of laminated glass and an increase in the YI value measured at the end part of the sheet of laminated glass can be suppressed. The interlayer film for laminated glass according to the present invention is provided with a first layer including a polyvinyl acetal resin and a plasticizer, and a second layer being arranged on a first surface side of the first layer and including a polyvinyl acetal resin and a plasticizer; and the first layer further including a hindered amine light stabilizer in which an alkyl group or an alkoxy group is bonded to a nitrogen atom of a piperidine structure.