Laminated Glass Interlayer Composition for TD Protrusion Suppression
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Solution Overview
Problem
Conventional interlayer films for laminated glass often result in protrusion issues during the production process, particularly in the transverse direction, due to air removal in vacuum bags, leading to inefficiencies and quality concerns.
Innovation Solution
The interlayer film incorporates a thermoplastic resin and a plasticizer, with controlled birefringence indices and glass transition temperatures, to suppress protrusion by maintaining a specific thickness and structural configuration, ensuring proper alignment and bonding between glass plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional interlayer film is used with vacuum bag for air removal, then laminated glass can be produced, but interlayer film protrudes from end part especially in TD direction
Solution Approach 1:
The patent applies parameter changes by controlling the glass transition temperature of the interlayer film to be 35°C or less and specifying birefringence index ranges (ΔnMDA, ΔnMDB, ΔnMDC each 0.03 to 0.25). These parameter adjustments modify the film's physical properties to reduce protrusion during vacuum bagging while maintaining bonding performance.
Solution Approach 2:
The patent uses composite materials by combining thermoplastic resin with plasticizer in specific ratios (plasticizer content 10-50 parts by weight per 100 parts resin). This composite structure achieves the desired glass transition temperature and mechanical properties that prevent protrusion during manufacturing.
2Ease of manufacture
If interlayer film is press-bonded and vacuumized to remove air, then laminated glass structure is formed, but interlayer film portion protrudes from end part
Solution Approach 1:
The patent modifies manufacturing parameters by controlling the interlayer film's glass transition temperature (≤35°C) and birefringence indices. These changes allow the film to maintain proper dimensions and flexibility during press-bonding and vacuumization, preventing protrusion while enabling easy production.
Solution Approach 2:
The patent applies preliminary action by pre-controlling the interlayer film's physical properties (glass transition temperature and birefringence) before the manufacturing process. This preliminary preparation ensures the film resists protrusion during subsequent press-bonding and vacuumization steps.
3Strength
If interlayer film has standard properties, then bonding between glass plates is achieved, but protrusion occurs in TD direction during vacuumization
Solution Approach 1:
The patent changes critical parameters by setting glass transition temperature ≤35°C and specifying birefringence index ranges. These parameter modifications create a balance where the film maintains sufficient adhesion strength while resisting protrusion forces during vacuumization, particularly in the TD direction.
Solution Approach 2:
The patent applies local quality by creating specific property zones within the interlayer film through controlled plasticizer distribution and orientation. The film exhibits different local characteristics that simultaneously provide adhesion to glass plates and resistance to protrusion during manufacturing.
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
This configuration effectively reduces protrusion of the interlayer film during laminated glass production, enhancing the manufacturing efficiency and quality by maintaining the interlayer film's position and adhesion, particularly in the transverse direction.
Implementation Method 1
the interlayer film contains a thermoplastic resin and a plasticizer... ΔnMDA, ΔnMDB, and ΔnMDC each are 0.03 to 0.25... glass transition temperatures
Implementation Method 2
ΔnMDA, ΔnMDB, and ΔnMDC each are 0.03 to 0.25... birefringence index in the machine flow direction
Data Source
Figure 1~3
Figure 4~5(c)
Figure 6(a)~6(c)
AI summary
There is provided an interlayer film for laminated glass with which protrusion of an interlayer film portion in the TD direction can be suppressed at the time of producing laminated glass. In the interlayer film for laminated glass according to the present invention, when, in the MD direction of the interlayer film, a birefringence index of the first surface part, a birefringence index of the second surface part, and a birefringence index of the center part are defined as ΔnMDA, ΔnMDB, and ΔnMDC, respectively, ΔnMDA, ΔnMDB, and ΔnMDC each are 0.25 × 10-3 or less.