Polyacetal Resin Composition for Hydrochloric Acid Crack Resistance
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Solution Overview
Problem
Polyacetal resin components, such as those used in fuel pump modules, are prone to cracking when exposed to hydrochloric acid-containing detergents, leading to potential damage.
Innovation Solution
Incorporating long chain fatty acid metal salts and stress relaxants with specific melting points into the polyacetal resin composition to enhance resistance against hydrochloric acid, specifically using metal salts of calcium, zinc, or magnesium, and stress relaxants like polyethylene oxide, to prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyacetal resin is used for fuel pump module components, then mechanical strength and chemical resistance are improved, but the components become prone to cracking when exposed to hydrochloric acid-containing detergents
Solution Approach 1:
The patent applies composite materials by combining polyacetal resin with specific additives: fatty acid metal salts (calcium, zinc, or magnesium stearate) and stress relaxants (polyethylene oxide or polypropylene glycol). This composite formulation creates a material that maintains the base resin's mechanical properties while adding resistance to hydrochloric acid stress cracking through the synergistic effect of the additives.
Solution Approach 2:
The patent changes the chemical composition parameters of the polyacetal resin by incorporating specific ratios of fatty acid metal salts (0.01-10 parts per 100 parts resin) and stress relaxants (0.1-5 parts per 100 parts resin). These parameter changes transform the material's resistance properties without fundamentally altering its mechanical function.
2Ease of manufacture
If conventional polyacetal resin composition is used, then ease of processing is maintained, but durability against hydrochloric acid-containing liquids is insufficient
Solution Approach 1:
The patent modifies the compositional parameters of the polyacetal resin by adding small amounts of fatty acid metal salts and stress relaxants within specific ranges. These parameter changes enhance durability while maintaining processability because the additive quantities are small enough not to significantly alter the resin's flow and molding characteristics.
Solution Approach 2:
The fatty acid metal salts and stress relaxants act as intermediary substances that mediate between the polyacetal resin matrix and the hydrochloric acid environment. These intermediaries provide chemical resistance and stress relaxation functionality while remaining compatible with the base resin's processing behavior.
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 modified polyacetal resin composition effectively prevents cracking when exposed to hydrochloric acid-containing liquids, demonstrating improved durability and resistance.
Implementation Method 1
0.1 to 5 parts by mass of a stress relaxant having a melting point of 67.5° C. to 200° C.
Implementation Method 2
0.01 to 10 parts by mass of at least one fatty acid metal salt selected from 1) to 3) below
Data Source
AI summary
To provide a polyacetal resin composition and a molded article thereof, which are less likely to crack even if stressed in contact with any hydrochloric acid-containing liquid. The polyacetal resin composition contains, per 100 parts by mass of a polyacetal resin: 0.01 to 10 parts by mass of at least one fatty acid metal salt selected from 1) to 3) below; and 0.1 to 5 parts by mass of a stress relaxant having a melting point of 67.5° C. to 200° C. when measured by using a differential scanning calorimeter at a flow rate of nitrogen of 20 cm3/min and at a heating rate of 10° C./min.1) metal salt formed of long chain fatty acid having 10 to 34 carbon atoms and calcium;2) metal salt formed of long chain fatty acid having 10 to 34 carbon atoms and zinc; and,3) metal salt formed of long chain fatty acid having 10 to 34 carbon atoms and magnesium.