Anti-soiling Agent Composition for Paper Machine Dry Parts
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Solution Overview
Problem
Existing anti-soiling agent compositions for paper-making machines are inadequate in preventing pitch adhesion to dry part regions due to high viscosity and stickiness issues, and insufficient mold-releasing and water-repellent properties.
Innovation Solution
An anti-soiling agent composition combining a low-molecular-weight polysiloxane compound with a high-molecular-weight polysiloxane compound, where the number of modified groups and repeating units satisfy a specific ratio, enhancing pitch dispersibility and adhesion prevention, and including emulsifiers for stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high molecular polysiloxane compound is used as an anti-soiling agent, then mold-releasing and water-repellant properties are improved, but viscosity becomes too high and stickiness increases, reducing effectiveness in preventing pitch adhesion
Solution Approach 1:
The invention divides the single polysiloxane compound into two distinct components: a low molecular polysiloxane compound (with 3-200 repeating units) and a high molecular polysiloxane compound (with 200-2000 repeating units). This segmentation allows each component to perform its specialized function - the low molecular compound provides flowability and pitch dispersibility, while the high molecular compound provides mold-releasing and water-repellant properties, resolving the contradiction between viscosity and effectiveness.
Solution Approach 2:
The invention changes the molecular weight parameter by using a distribution of polysiloxane chain lengths rather than a single molecular weight. The low molecular compound (shorter chains) reduces viscosity and stickiness while the high molecular compound (longer chains) maintains the necessary protective properties. This parameter change enables the composition to overcome the limitations of using a single high molecular weight compound.
2Ease of operation
If a low molecular polysiloxane compound is used, then flowability and pitch dispersibility are improved, but mold-releasing and water-repellant properties become insufficient
Solution Approach 1:
The invention segments the polysiloxane composition into two molecular weight classes, assigning the low molecular compound (3-200 repeating units) the task of providing flowability and pitch dispersibility, while the high molecular compound (200-2000 repeating units) is assigned the task of providing mold-releasing and water-repellant properties. This functional segmentation resolves the contradiction between ease of operation and reliability.
Solution Approach 2:
The invention merges two polysiloxane compounds with different molecular weights into a single anti-soiling agent composition. The low molecular compound contributes flowability and pitch dispersibility, while the high molecular compound contributes mold-releasing and water-repellant properties. The synergistic combination of these two components resolves the limitation of using either compound alone.
3Reliability
If the number of modified groups per polysiloxane molecule is increased, then adhesion prevention is improved, but viscosity and stickiness increase, reducing overall effectiveness
Solution Approach 1:
The invention applies local quality by having different numbers of modified groups in different molecular weight classes. The low molecular polysiloxane compound has 0.1-3 modified groups per molecule (providing flowability), while the high molecular polysiloxane compound has 1.0-10 modified groups per molecule (providing adhesion prevention). This localized differentiation of modified group density resolves the contradiction between adhesion prevention and viscosity control.
Solution Approach 2:
The invention changes the parameter of modified group concentration by using a distribution across different molecular weights rather than uniform modification. The lower molecular weight compounds have fewer modified groups (reducing viscosity), while the higher molecular weight compounds have more modified groups (enhancing adhesion prevention). This parameter differentiation resolves the contradiction between reliability and harmful factors.
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
Effectively prevents pitch adhesion to dry part regions, improving paper yield by forming a coat film and dispersing pitch, while maintaining stability and flowability, even on high-temperature surfaces.
Implementation Method 1
by applying the resultant anti-soiling agent composition to a dry part region, the high molecular polysiloxane compound exerts an effect for preventing pitch adhesion thereto, while the low molecular polysiloxane compound exerts an effect for dispersing the pitch
Implementation Method 2
the low molecular polysiloxane compound exerts an effect for dispersing the pitch
Data Source
AI summary
[Object] To provide an anti-soiling agent compound that can sufficiently prevents adhesion of pitch to a dry part region.[Solution] The present invention provides an anti-soiling agent composition is provided with: a low molecular polysiloxane compound represented by the following formula (1); and a high molecular polysiloxane compound represented by the following formula (2), and characterized in that the number of modified groups per low molecular polysiloxane compound is in a range from 0.1 to 3, the number of modified groups per high molecular polysiloxane compound is in a range from 1.0 to 10, and the number m of repeating polysiloxane units in the low molecular polysiloxane compound and the number n of repeating polysiloxane units in the high molecular polysiloxane compound have the following relationship: 2 m≦n,[in formula (1), substituent R1 represents a methyl group or a modified group, with the repeating number m being set to an integer from 20 to 200], and[in formula (2), substituent R2 represents a methyl group or a modified group, with the repeating number n representing an integer].