Multilayer Solar Module Sealing Sheet Without Crosslinking

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Solution Overview

Problem

Existing sealing material sheets for solar-cell modules, particularly those using polyethylene-based resins, face challenges in achieving high heat resistance, molding characteristics, and high tensile shear adhesion force at normal temperature without crosslinking processing, especially in frameless double-sided glass protecting substrate type modules.

Innovation Solution

A multi-layer sealing material sheet composed of a core layer and skin layers using silane-modified polyethylene-based resins with specific molecular weights and densities, ensuring a melting point of 70°C or higher for the core layer and 90°C or lower for the skin layer, without crosslinking treatment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If crosslinking treatment is performed to improve heat resistance, then heat resistance is reliably improved, but molding characteristics deteriorate and followability to surface irregularities cannot be maintained

Engineering Contradiction:

Improveheat resistanceVSAvoidmolding characteristics

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The sealing material sheet is divided into a core layer and skin layers with different functions. The core layer provides heat resistance through crosslinking, while the skin layers maintain molding characteristics and followability without crosslinking, thus resolving the contradiction between heat resistance and molding characteristics

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the sealing material sheet have different properties: the core layer is crosslinked for heat resistance, while the skin layers remain non-crosslinked for good molding characteristics and followability to surface irregularities

Inventive Principle:

Principle #3Local quality

2Temperature

If crosslinking treatment is performed to improve heat resistance, then heat resistance is improved, but productivity decreases due to additional processing steps and film formation ability loss

Engineering Contradiction:

Improveheat resistanceVSAvoidproductivity

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The crosslinking treatment is performed preliminarily on the core layer before final assembly, allowing the skin layers to maintain their molding characteristics. This preliminary crosslinking of only the necessary portion reduces the impact on overall productivity while achieving the required heat resistance

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If density of polyethylene-based resin is decreased to improve transparency and flexibility, then transparency and flexibility are improved, but heat resistance becomes insufficient

Engineering Contradiction:

ImproveflexibilityVSAvoidheat resistance

Core Design Contradiction:

Ease of operationVSTemperature

Solution Approach 1:

The density of the polyethylene-based resin is optimized to balance transparency, flexibility, and heat resistance. By controlling the density parameter within a specific range, the sealing material achieves adequate flexibility for molding while maintaining sufficient heat resistance for solar cell module application

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sealing material uses a composite structure with a core layer and skin layers made of polyethylene-based resin with optimized density. This composite structure allows the material to exhibit both flexibility from the optimized density and heat resistance from the crosslinked core layer

Inventive Principle:

Principle #40Composite materials

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 provides a sealing material sheet with high productivity, excellent heat resistance, and high tensile shear adhesion force at normal temperature, maintaining molding characteristics and suitability for frameless double-sided glass protecting substrate type solar-cell modules.

Implementation Method 1

the heat resistance is imparted by a crosslinking agent. In this case, the heat resistance is reliably improved. However, when a crosslinking treatment is performed to an extent that is sufficient and necessary for providing sufficient heat resistance

Methodology Applied

Scientific EffectCrosslinking reaction: Chemical Bonding

Implementation Method 2

a problem arises in that followability (hereinafter, referred to as 'molding characteristics') to irregularities on a surface of a facing member cannot be maintained

Methodology Applied

Scientific EffectDeformation: Deformation

Data Source

PatentUS12520604B2Sealing material sheet for solar-cell module and solar-cell module using the same

Publication Date: 2026.01.06 DAI NIPPON PRINTING CO LTD

AI summary

To provide a sealing material sheet for a solar-cell module that has high productivity without performing crosslinking processing, and has a high tensile shear adhesion force at normal temperature at a high level in addition to heat resistance and molding characteristics. A sealing material sheet is a multi-layer sheet using a polyethylene-based resin as a base resin, a core layer has a density of 0.880 g/cm3 to 0.895 g/cm3 and a melting point of 70° C. or higher, a skin layer has a density of 0.880 g/cm3 to 0.910 g/cm3 and a melting point of 90° C. or lower and contains a silane-modified polyethylene-based resin, a weight average molecular weight of the silane-modified polyethylene-based resin contained in the skin layer 11 in terms of polystyrene is 70000 to 120000, and a polymerized silane amount of the skin layer in the whole resin component is 300 ppm to 2000 ppm.