Room-temperature-curable organopolysiloxane composition and production method for same
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Solution Overview
Problem
Existing room temperature-curable organopolysiloxane compositions used in building sealants face challenges in maintaining low to medium modulus elasticity over a long term, causing bleeding stains on porous materials like natural rock and poor adhesion to substrates, while also suffering from storage stability issues and cure inhibition.
Innovation Solution
A composition comprising diorganopolysiloxane, a hydroxy-containing hydrocarbon compound, chloroplatinic acid, an inorganic filler, an organosilane with hydrolyzable groups, a condensation curing catalyst, and a silane coupling agent is mixed to form a reaction product, minimizing non-functional silicone oil content and ensuring adhesion to substrates, reducing modulus, and enhancing storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plasticizers are added to reduce modulus of elasticity, then low modulus properties are achieved, but staining problems occur during long-term use
Solution Approach 1:
The invention removes the plasticizer component entirely from the sealant formulation. Instead of adding plasticizers to reduce modulus, the patent achieves low modulus properties through careful selection of base polymer viscosity and crosslink density, thereby eliminating the source of staining problems while maintaining the desired elasticity properties.
Solution Approach 2:
The invention changes the approach to achieving low modulus from chemical addition (plasticizers) to parameter control (base polymer viscosity and crosslink density). By adjusting these parameters, the patent achieves the same mechanical properties without the harmful side effects of plasticizer migration and staining.
2Object-generated harmful factors
If plasticizer-free composition is used to avoid staining, then staining is reduced, but cured rubber has high modulus and poor adhesion
Solution Approach 1:
The invention adjusts the viscosity of the base polymer and the crosslink density through controlled crosslinking reactions to achieve the desired balance between modulus and adhesion without requiring plasticizers. This parameter optimization allows plasticizer-free formulations to meet both mechanical performance and aesthetic requirements.
3Stability of the object's composition
If conventional crosslinking agents are used to reduce crosslink density, then storage stability improves, but cure inhibition occurs and residual free oil becomes contamination source
Solution Approach 1:
The invention removes problematic crosslinking agents that cause cure inhibition and residual free oil contamination. Instead, it uses controlled crosslinking mechanisms that form stable networks without leaving harmful residues, thereby eliminating both storage stability issues and contamination problems.
Solution Approach 2:
The invention employs crosslinking mechanisms that complete their function during curing and leave no persistent harmful components. The crosslinking process is designed to be self-limiting, forming stable networks without generating residual free oil or causing cure inhibition, thus eliminating long-term contamination issues.
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 composition cures into a silicone rubber with low modulus elasticity, minimal bleeding stains, and excellent adhesion to substrates, maintaining properties over time and offering improved storage stability.
Implementation Method 1
a room temperature-curable organopolysiloxane composition which crosslinks or cures at room temperature through condensation cure reaction with the aid of airborne moisture
Implementation Method 2
an organosilane having at least 3 hydrolyzable groups per molecule and/or a partial hydrolytic condensate thereof
Implementation Method 3
a condensation curing catalyst
Data Source
AI summary
A room-temperature-curable organopolysiloxane composition that contains: 100 parts by mass of the product of reacting (A) a diorganopolysiloxane that is capped at both ends by a hydroxyl group, a hydroxy-group-containing hydrocarbon compound in such an amount as for there to be 0.01-0.5 mol per 1 mol of hydroxyl groups that are bonded to silicon atoms in the diorganopolysiloxane, and platinic chloride hexahydrate in an amount that is 0.01-1 mass % of the total of component (A); (B) 3-300 parts by mass of an inorganic filler; (C) 1-20 parts by mass of an organosilane that has at least 3 hydrolyzable groups per molecule thereof and/or a partial hydrolysis condensate of an organosilane that has at least 3 hydrolyzable groups per molecule thereof; (D) 0.01-5 parts by mass of a condensation cure catalyst; and (E) 0.1-5 parts by mass of a silane coupling agent (excluding component (C) and component (D)). The room-temperature-curable organopolysiloxane composition gives cured products that retain low-elastic-modulus rubber elasticity over long periods of time and do not readily contaminate natural rock, coated aluminum, or the like.