Polyamide Hose Inner Layer Acid Acceptors for Refrigerant Durability
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Solution Overview
Problem
Conventional rubber hoses for car air conditioning systems using HFO-1234yf as a refrigerant exhibit low deterioration resistance due to chemical attacks, leading to hydrolysis of the polyamide innermost layer and subsequent decline in performance.
Innovation Solution
A hose with an innermost layer formed from a polyamide resin composition containing a polyamide and an acid acceptor, such as hydrotalcite, magnesium oxide, or calcium hydroxide, which traps acidic components and suppresses hydrolysis, combined with a carboxyl group-containing modified polyolefin and an acid sealing agent to enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional polyamide innermost layer is used in rubber hoses for HFO-1234yf refrigerant systems, then the hose structure is simple and manufacturing is easy, but the deterioration resistance performance is low due to chemical attacks causing hydrolysis
Solution Approach 1:
The patent applies composite materials by combining polyamide resin with specific additives (acid acceptors like metal hydroxides or oxides, and acid sealing agents) to create a multi-functional innermost layer. This composite structure provides both the inherent chemical resistance of polyamide and the protective functions of the additives, preventing hydrolysis from acidic decomposition products while maintaining structural integrity and durability in HFO-1234yf refrigerant systems
Solution Approach 2:
The patent uses acid acceptors (such as metal hydroxides or oxides) as intermediary substances that neutralize acidic decomposition products before they can attack the polyamide resin. These intermediaries act as a protective buffer between the refrigerant environment and the polyamide structure, preventing direct chemical attack and hydrolysis while allowing the polyamide to maintain its barrier properties
2Reliability
If acid acceptors and acid sealing agents are added to the polyamide resin composition, then deterioration resistance improves, but manufacturing precision and composition control become more difficult
Solution Approach 1:
The patent specifies precise parameter ranges for the additive concentrations (0.1-10 parts by mass of acid acceptor and 0.01-5 parts by mass of acid sealing agent per 100 parts of polyamide resin) to optimize performance while ensuring manufacturability. These parameter specifications provide clear manufacturing targets that balance deterioration resistance improvement with composition control feasibility, allowing consistent quality through defined compositional parameters
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 solution provides a hose with superior deterioration resistance performance, maintaining mechanical properties and flexibility over extended periods, even under high-temperature conditions, while preventing refrigerant permeation and reducing vibration-induced noise.
Implementation Method 1
an innermost layer formed using a polyamide resin composition comprising a polyamide and, per 100 parts by mass thereof, from 0.5 to 20 parts by mass of an acid acceptor
Implementation Method 2
laminated structures of a rubber and a resin comprising an innermost layer formed from a polyamide resin material in order to suppress the permeation of a refrigerant
Data Source
Figure 1
AI summary
The purpose of the present invention is to provide a hose for refrigerant transport use comprising an inner layer with superior deterioration resistance performance. The innermost layer comprised in the hose for refrigerant transport use of the present invention is formed using a polyamide resin composition comprising a polyamide and, per 100 parts by mass thereof, from 0.5 to 20 parts by mass of an acid acceptor.