Solar Cell Back Sheet Coating Using Blocked Isocyanate
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Solution Overview
Problem
The existing solar cell module back sheet coatings suffer from poor glossiness, inadequate solvent resistance, adhesive properties, and high yellowing, which affect storage stability and performance.
Innovation Solution
A curable composition comprising a blocked isocyanate, a curable functional group-containing fluorine polymer, and an alkoxysilane, with titanium oxide as an optional component, is used to create a coating material that enhances glossiness, solvent resistance, and adhesive properties while maintaining low yellowing and storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a curable functional group-containing fluorine polymer and a blocked isocyanate based on hexamethylene diisocyanate are used as coating materials, then the coating film can be formed with basic protective properties, but the glossiness of the coating film deteriorates
Solution Approach 1:
The invention changes the chemical parameters of the isocyanate compound from hexamethylene diisocyanate to bis(isocyanatomethyl)cyclohexane, and specifies a particular molar ratio range (0.05-0.5) between the curable functional group and isocyanate group. This parameter optimization resolves the contradiction by achieving both good glossiness and reliable coating film quality simultaneously.
2Reliability
If conventional coating materials are used to form a curing coating film, then the film can provide basic protection, but solvent resistance deteriorates
Solution Approach 1:
The invention creates a composite curing system combining curable functional group-containing fluorine polymer, specific blocked isocyanate, and silane compound. This composite material approach achieves both excellent solvent resistance and adhesive properties that cannot be obtained with single materials.
3Shape
If the coating material formulation is optimized for glossiness, then storage stability may deteriorate
Solution Approach 1:
The blocked isocyanate based on bis(isocyanatomethyl)cyclohexane acts as an intermediary that provides both glossiness enhancement and storage stability. The blocking mechanism allows the isocyanate to remain stable during storage while still providing the desired gloss effect, and activates only during curing.
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 solution achieves a curing coating film with improved glossiness, solvent resistance, adhesive properties, and low yellowing, ensuring excellent storage stability and performance, particularly suitable for solar cell modules.
Implementation Method 1
a curable composition containing a blocked isocyanate, a curable functional group-containing fluorine polymer, and an alkoxysilane as essential components
Implementation Method 2
the alkoxysilane has a functional group including at least one kind of element selected from the group consisting of a group 15 element to a group 16 element of the periodic table
Implementation Method 3
an alkoxysilane as essential components
Data Source
AI summary
A curable composition includes a blocked isocyanate in which an NCO group of an isocyanate compound having a H6XDI skeleton is blocked by a blocking agent having an O═C—CH—C═O skeleton, a curable functional group-containing fluorine polymer, and an alkoxysilane having a functional group including at least one element of a group 15 element to a group 16 element of the periodic table (excluding oxygen). In the curable composition allowing a titanium oxide to be contained, the molar ratio of the curable functional group to the NCO group is 0.5 to 10; the content ratio of the alkoxysilane with respect to 100 pans by mass of the total amount of the blocked isocyanate and the fluorine polymer is 0.2 to 8 parts by mass; and the content ratio of the titanium oxide with respect to 100 parts by mass of the fluorine polymer is 0 to 200 parts by mass.