Starch-Containing Polymer Dispersions for Paper Sizing
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Solution Overview
Problem
There is a need for new, effective bulking and surface sizing agents for the production of paper, paperboard, and cardboard that offer improved performance compared to existing solutions.
Innovation Solution
Finely divided, starch-containing polymer dispersions are produced through free-radically initiated emulsion polymerization using ethylenically unsaturated monomers, redox initiators, and terpene-containing regulators, with specific compositions of styrene, acrylic acid esters, and degraded starch to enhance sizing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional emulsion polymerization is used with peroxide initiators and degraded starch, then polymer dispersions can be produced for paper sizing, but the sizing effect is insufficient and application quantities must be large
Solution Approach 1:
The patent changes the chemical parameters of the polymerization system by introducing terpene-containing regulators (specifically hydroperoxides of terpenes like limonene or terpinolene) and using redox initiator systems instead of conventional peroxide initiators. This parameter change results in polymer dispersions with significantly improved sizing effect, allowing reduction of application quantities while maintaining or enhancing performance.
2Reliability
If polymerization regulators are not used, then the polymerization process is simpler, but the molecular weight and sizing performance are insufficient
Solution Approach 1:
The patent introduces terpene-containing polymerization regulators (hydroperoxides of terpenes) to control molecular weight and improve sizing performance. The specific parameter change involves using these natural terpene derivatives as regulators, which provides the necessary molecular weight control for effective sizing while maintaining process simplicity.
3Reliability
If redox initiators and terpene-containing regulators are used, then the sizing effect is significantly increased, but the formulation complexity increases
Solution Approach 1:
The patent creates a composite polymerization system combining redox initiators (such as ammonium persulfate/sodium bisulfite or hydrogen peroxide/ferrous sulfate) with terpene-containing regulators. This composite approach leverages the synergistic effects of different components to achieve superior sizing effect while managing formulation complexity through systematic combination of well-defined chemical systems.
Solution Approach 2:
The terpene-containing regulators act as intermediary substances that mediate between the redox initiator system and the polymerization process. These intermediaries control the polymerization kinetics and molecular weight distribution, enabling the redox system to produce polymers with optimized sizing properties without requiring direct complex interaction between all components.
4Reliability
If conventional polymerization methods are used, then the process is well-established, but the effectiveness as sizing agent is limited
Solution Approach 1:
The patent modifies conventional polymerization parameters by introducing terpene-containing regulators and redox initiator systems, transforming a well-established process into one that produces polymers with significantly enhanced sizing effectiveness. The parameter changes maintain the fundamental emulsion polymerization framework while optimizing performance through controlled molecular weight and polymer structure.
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 resulting polymer dispersions demonstrate a significantly increased sizing effect on paper, cardboard, and cardboard, providing better performance even with small application quantities, especially on uncoated wood-free papers.
Implementation Method 1
emulsion polymerization of ethylenically unsaturated monomers in the presence of at least one redox initiator
Implementation Method 2
polymerization takes place in the presence of at least 0.01% by weight, based on the monomers used, of at least one terpene-containing polymerization regulator
Implementation Method 3
free-radically initiated emulsion polymerization of ethylenically unsaturated monomers
Data Source
AI summary
The invention relates to finely divided starch-containing polymer dispersions, which can be obtained by the radically initiated emulsion polymerization of ethylenically unsaturated monomers in the presence of at least one redox initiator and starch, wherein the ethylenically unsaturated monomers used are (a) 30 to 60% by weight of at least one optionally substituted styrol, (b) 1 to 60% by weight of at least one acrylic acid-C1-C12-alkyl ester and/or methacrylic acid-C1-C12-alkyl ester, (c) 0 to 10% by weight of at least one other ethylenically unsaturated copolymerizable monomer, and the starch used is (d) 15 to 40% by weight of at least one degraded starch having a molar mass Mw of 1000 to 65000 g/mol, wherein the sum (a) + (b) + (c) + (d) = 100% and relates to the total solid matter content, and wherein the polymerization is carried out in the presence of at least 0.01% by weight, relative to the monomers used, of at least one terpene-containing polymerization regulator. The invention further relates to a method for producing the finely divided starch-containing polymer dispersions by means of the emulsion polymerization of monomers (a), (b) and (c) using redox initiators in the presence of (d) degraded starch and at least 0.01% by weight, relative to the monomers used, of at least one terpene-containing polymerization regulator, and to the use of the finely divided starch-containing polymer dispersions as a sizing agent for paper, paperboard and cardboard.