Pressure-Sensitive Adhesive Composition Low-Temperature Performance
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Solution Overview
Problem
Existing adhesive materials fail to maintain effective adhesion and cohesion at low temperatures, particularly in cold and moist conditions, often relying on C1-C2 alkyl (meth)acrylates, sulfonic groups, or diesters of unsaturated dicarboxylic acids which are not used in this composition.
Innovation Solution
A pressure-sensitive adhesive composition based on an aqueous polymer dispersion with a monomeric mixture of 2-ethylhexyl acrylate, n-butyl methacrylate, vinyl aromatic monomers, ethylenically unsaturated acid, and vinylic esters, excluding C1-C2 alkyl (meth)acrylates, sulfonic groups, and diesters, utilizing a chain transfer agent to control molecular weight, enhancing adhesion and cohesion at temperatures below 10°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If C1-C2 alkyl (meth)acrylates are used to improve adhesion at low temperatures, then adhesion performance is improved, but the composition becomes less environmentally friendly and more expensive
Solution Approach 1:
The patent changes the chemical parameters of the adhesive composition by replacing C1-C2 alkyl (meth)acrylates with alternative monomers (C3-C12 alkyl (meth)acrylates, vinyl esters, and carboxylic acid monomers) that achieve similar low-temperature adhesion performance without the environmental and cost drawbacks of the conventional monomers
Solution Approach 2:
The patent uses readily available, cost-effective monomers such as vinyl acetate and common alkyl (meth)acrylates to replace more expensive specialized monomers, achieving comparable performance at lower cost
2Reliability
If C1-C2 alkyl (meth)acrylates are used to maintain adhesion at low temperatures, then adhesion is improved, but production cost increases
Solution Approach 1:
The patent modifies the monomeric composition parameters to use more cost-effective monomers (vinyl acetate, C3-C12 alkyl (meth)acrylates) that are commercially more available and less expensive than C1-C2 alkyl (meth)acrylates, while maintaining the required adhesion performance through optimized formulation
Solution Approach 2:
The patent employs vinyl acetate and other versatile monomers that can serve multiple functions (adhesion, flexibility, low-temperature performance) in a single composition, reducing the need for multiple specialized additives and simplifying the formulation process
3Reliability
If sulfonic groups are used to enhance adhesion in cold conditions, then adhesion performance is improved, but the composition becomes less environmentally friendly
Solution Approach 1:
The patent changes the chemical composition by excluding sulfonic groups and instead using carboxylic acid monomers (acrylic acid, methacrylic acid) and vinyl esters that provide similar adhesion enhancement in cold conditions without the environmental concerns associated with sulfonic groups
Solution Approach 2:
The patent uses conventional, readily biodegradable monomers like acrylic acid and vinyl acetate that are environmentally more friendly than sulfonic group-containing compounds, achieving the same functional effect with more sustainable materials
4Strength
If diesters of unsaturated dicarboxylic acids are used to improve cohesion, then cohesion is improved, but the composition becomes more complex and expensive
Solution Approach 1:
The patent simplifies the composition by using single-function monomers (vinyl esters, alkyl (meth)acrylates) that provide both adhesion and cohesion properties, eliminating the need for complex diester additives and reducing overall formulation complexity
Solution Approach 2:
The patent employs vinyl esters and alkyl (meth)acrylates that serve multiple functions simultaneously (adhesion promotion, cohesion maintenance, flexibility), replacing the need for separate specialized additives and simplifying the overall composition
5Reliability
If conventional monomers are used to achieve adhesion, then adhesion is maintained, but the adhesive fails to maintain cohesion at low temperatures
Solution Approach 1:
The patent optimizes the balance between adhesion and cohesion by carefully controlling the ratios of different monomers in the composition, ensuring that the adhesive maintains both properties at low temperatures through compositional optimization rather than relying on single-component extremes
Solution Approach 2:
The patent creates a composite monomeric system where different monomers (alkyl (meth)acrylates for adhesion, vinyl esters for flexibility, carboxylic acids for bonding) work synergistically to provide both adhesion and cohesion at low temperatures, achieving a balanced performance that neither component could provide alone
Data Source
AI summary
The invention relates to a pressure sensitive adhesive composition, which comprises an aqueous polymer dispersion which comprises at least one polymer with monomeric units from a monomeric composition comprising : a) 60 to 95% by weight of 2-ethylhexyl acrylate, b) 0.1 to 15% by weight of butyl (meth)acrylate, c) 0.5 to 5% by weight of a vinyl aromatic monomer, d) 0.1 to 4% by weight of at least one ethylenically unsaturated acid, e) 0 to 20% by weight of a vinylic ester of C 2 -C 8 carboxylic acid, f) optionally, a monomer different from a), b), c), d) and e) as defined above g) at least 0.005% by weight with respect to the total weight of monomers a) + b) + c) + d) + e) + f) of at least one chain transfer agent the sum of a) + b) +c) + d) + e) + f) being equal to 100% and with the proviso that said monomeric composition does not comprise any C -C 2 alkyl (meth)acrylate. The invention does also relate to said aqueous polymer dispersion and its use in PSA compositions.