초록 ▼

○ 발포제 혼합비율에 따른 밀도는 31이상㎏/㎥으로 유사한 범위로 나타났다.압축강도는 10:20:35:35%, 25:5:35:35%에서 KS M 3808 발포 폴리스티렌의 기준에 만족하지 못 하였으며, 굴곡파괴하중은 기준 보다 3～41%로 만족함. 또한 투습계수는 기준 보다 9～63%로 만족함.
○ 초기열전도율은 혼합비율 10:20:30:40%, 10:20:35:35%, 25:5:30:40%,25:5:35:35%에서 현행 KS M 3808 초기열전도율 기준에 만족하지 못 하였으며, 장기열전도율은 10:20:20:50%, 15:

○ 발포제 혼합비율에 따른 밀도는 31이상㎏/㎥으로 유사한 범위로 나타났다.압축강도는 10:20:35:35%, 25:5:35:35%에서 KS M 3808 발포 폴리스티렌의 기준에 만족하지 못 하였으며, 굴곡파괴하중은 기준 보다 3～41%로 만족함. 또한 투습계수는 기준 보다 9～63%로 만족함.
○ 초기열전도율은 혼합비율 10:20:30:40%, 10:20:35:35%, 25:5:30:40%,25:5:35:35%에서 현행 KS M 3808 초기열전도율 기준에 만족하지 못 하였으며, 장기열전도율은 10:20:20:50%, 15:15:20:50%, 15:15:25:45%, 20:10:20:50%,20:10:25:45%에서 KS M 3808 기준에 만족함.
○ 발포제 혼합비율 따른 단열재의 압축강도, 굴곡파괴하중, 열전도율(초기, 장기), 투습계수, 연소성 등을 분석한 결과, Cell size가 0.31㎜로 나타난 15:15:20:50%와 0.33㎜로 나타난 20:10:20:50%에서 KS M 3808 기준 보다 상회하는 것으로 나타남.
○ CO₂ 활용을 위한 압출법 단열재의 발포제 혼합비율은 열전도율의 안정성을 고려하여 15:15:20:50%, 20:10:20:50%에서 적용이 가능할 것으로 판단.
○ CO₂를 단열재의 발제로 활용을 위하여 KS M 3808 규격의 종류를 A타입(탄화수소, 이산화탄소 등을 발포제로 사용하여 프레온류를 사용하지 않은 것)과 B타입(프레온류를 발포제로 사용하는 것)으로 적용하여 이에 대한 제한적인 기준이 아니라 국제적인 추세인 발포제 대체재료의 활성화를 위하여 장기열전도율을 삭제하는 방안으로 제안.

Abstract ▼

Ⅳ. Contents and Results of Research and Development Performance

The findings from research and development during the first, second and third year are shown below;

[ First year]

Study contents:▪ Survey on the status of domestic and foreign technology development
Study result

Ⅳ. Contents and Results of Research and Development Performance

The findings from research and development during the first, second and third year are shown below;

[ First year]

Study contents:▪ Survey on the status of domestic and foreign technology development
Study results:
▪ Europe and other foreign countries have used materials from HFC to CO₂ and Japan secured the production technology of replacement with hydrocarbons(applying additives of graphite, carbon black, etc., developing micro cell, complex cell, etc. from the improvement of cell structure as the foaming technology)
▪ It is identified that our country is using HCFC foaming agents. (The XPS business stays at the early stage with a passive approach depending on the technology of companies which have imported extrusion machines from the advanced countries.)

Study contents:▪ Design plans to secure the insulation performance of environmentally friendly foaming agents
Study results:
▪ As CO₂ has high vitality with little role of lowering thermal conductivity, its thermal conductivity increases in a short time without change over time. Use graphite to lower thermal conductivity due to these problems and lower the cell size to design a method in minimizing heat delivery (conductivity, convection current and radiation)

Study contents:▪ Review the production process of partial substitution for environmentally friendly foaming agents
Study results:
▪ Derive process conditions on the first extruder pressure 1,600psi and temperature 200℃ → on the second extruder pressure 850psi and temperature 115℃

Study contents:▪ Performance evaluation on insulators using CO₂ as a substitutional foaming agent
Study results:
▪ As a result of performance evaluation on the compression strength, flexural destruction load, thermal conductivity, combustibility and moisture permeance of 50 ~ 75mm insulators with CO₂ substitution under process conditions of the first extruder pressure 1,300psi and temperature 200℃ → the second extruder pressure 700psi and temperature 115℃, it met KSM 3808 foaming polystyrene standards but initial thermal conductivity met the low levels of the current standards and long-term thermal conductivity did not meet standards.
▪ As a result of performance evaluation on the compression strength, flexural destruction load, thermal conductivity, combustibility and moisture permeance of 100 ~ 110mm insulators with CO₂ substitution under process conditions of the first extruder pressure 1,300psi and temperature 220℃ → the second extruder pressure 700psi and temperature 125℃, it met KSM 3808 foaming polystyrene standards but initial thermal conductivity met the low levels of the current standards and long-term thermal conductivity did not meet standards.
▪ 20% or more can be considered applicable for the increased CO₂ use as a substitutional foaming agent, and it can be applied to 50 ~ 75mm thick insulators because performance for 50 ~ 75mm thick insulators appeared to be higher than that for 100 ~ 110mm thick insulators.
▪ As a result of experiments on the compression strength, flexural destruction load, thermal conductivity, combustibility and moisture permeance of insulators according to CO₂ substitution ratios under maximum process conditions of the first extruder pressure 1,600psi and temperature 220℃ → the second extruder pressure 850psi and temperature 125℃, it met KS M 3808 foaming polystyrene standards, 30% or more of CO₂ can be applicable, and performance on thermal conductivity met the low levels of the current standards.
▪ As a result of performance evaluation according to CO₂ substitution ratios for optimal condition setting, compression strength, flexural destruction load, thermal conductivity, combustibility and moisture permeance met 4 ~ 64% to KS M 3808 foaming polystyrene standards,and process conditions are considered applicable to the condition of the first extruder pressure 1,600psi and temperature 200℃ → the second extruder pressure 850psi and temperature 115℃

Study contents:▪ Performance evaluation on insulators with the addition of graphite
Study results:
▪ As a result of performance evaluation on insulators with the addition of graphite, compression strength, flexural destruction load, thermal conductivity, combustibility and moisture permeance met 4 ~ 60% of KSM 3808 foaming polystyrene standards.
▪ Up to 30% substitution can be considered possible for the increased use of CO₂ as a substitutional foaming agent, and performance on thermal conductivity met the low levels of the current standards, but the effect on performance improvement for insulators is thought to exist due to the application of graphite.

[Second year]

Study contents:▪ Supplementary review on production facilities for improvements on insulator performance
Study results:
▪ Problems such as increased density,increased thermal conductivity, unstable surface and decreased thickness occurred due to the increased CO₂ substitution ratios, which are thought to result from unstable cell structure, high temperature, low air pressure, mixed foaming agents, etc. Accordingly, the review on materials such as additional foaming agents was requested as cost problem occurred although extruders had to be replaced.
▪ As a result of the equipment replacement with thickness adjustment of 470mm → 450mm for die supplementation, the cell structure was considered improved due to the increased die pressure from thickness adjustment.

Study contents:▪ Performance evaluation on insulators according to CO₂ substitution ratios where optimal conditions are applied
Study results:
▪ As a result of performance evaluation on insulators according to CO₂ substitution ratios where optimal conditions are applied in the first extruder pressure 1,600psi and temperature 200℃ → the second extruder pressure 850psi and temperature 115℃,compression strength is met by 18% or more, flexural destruction load by 45% or more, moisture permeance by 61% or more and combustibility met KS M 3808 foaming polystyrene standards according to the increase of CO₂ substitution ratio by 35~50%, but initial thermal conductivity and long-term thermal conductivity failed to be met in 35% or more of CO₂ substitution ratio.
▪ As a result of up to 50% application for the increased use CO₂ as a substitutional foaming agent, the improvement and supplementation on the component materials for insulators were considered necessary because performance on thermal conductivity met the low levels of the current standards.

Study contents:▪ Long-term durability review on insulators with the addition of graphite
Study results:
Although compression strength, flexural destruction load, thermal conductivity(initial and long-term), combustibility and moisture permeance met KS M 3808 standards at a 5% addition ratio of graphite with a 30% CO₂ substitution ratio, twist occurred for long-term durability and review on supplementary and additional materials was request for it.

Study contents:▪ Performance evaluation on insulators according to mixing ratios of a subsidiary foaming agent(ethanol)
Study results:
▪ As a result of performance evaluation on insulators according to mixing ratios of a subsidiary foaming agent (ethanol), compression strength is met by 29% or more, flexural destruction load by 31% or more, moisture permeance by 60% or more and combustibility met KSM 3808 foaming polystyrene standards according to the increase of mixing ratios of a subsidiary foaming agent (ethanol) by 5~ 25%, and initial and long-term thermal conductivity is met at 20% or more of mixing ratios with a subsidiary foaming agent (ethanol).
▪ The review on the second subsidiary foaming agent was requested as 20% or more of mixing ratios with a subsidiary foaming agent (ethanol) was considered applicable to the increased use of CO₂ as a substitutional foaming agent.

Study contents:▪ Cell structure improvement according to pressure variations at the second extruder
Study results:
▪ As a result of cell structure improvement according to pressure variations at the second extruder, initial thermal conductivity is met by 4% or more and long-term thermal conductivity by 2% or more than KS M 3808 foaming polystyrene standards at 900psi or more for insulation performance according to the increase of pressure to 850 ~ 1,000psi at the second extruder, and 950psi for the second extruder pressure was considered applicable stably in consideration of insulation performance and economy.

Study contents:▪ Performance evaluation where CO₂, subsidiary foaming agent and cell structure improvement technology are applied
Study results:
▪ As a result of performance evaluation on insulators where CO₂, subsidiary foaming agent and cell structure improvement technology are applied, compression strength is met by 22% or more, flexural destruction load by 29% or more, initial thermal conductivity by 5% or more, moisture permeance by 58% or more and combustibility meet KS M 3808 foaming polystyrene standards according to mixing ratios of foaming agents, and long-term thermal conductivity is met at mixing ratios of foaming agents for 30:20:50% or more.
▪ Optimal conditions of insulators where CO₂, subsidiary foaming agent and cell structure improvement technology are applied were considered applicable at mixing ratios of foaming agents for 30:20:50% or more based on long-term thermal conductivity.

[Third year (Final year) ]

Study contents:▪ Optimization and practical use of temperature and pressure control flow using environmentally friendly foaming agents
Study results:
▪ As a result of our review on extrusion process conditions with the first extruder pressure 1,400psi, 1,500psi and 1,600psi at temperature 200℃ → the second extruder pressure 750psi, 850psi and 950psi at temperature 115℃, optimal conditions were derived with the first extruder pressure 1,600psi and temperature 200℃→ the second extruder pressure 950psi and temperature 115℃.

Study contents:▪ Performance evaluation on insulators using 50% of environmentally friendly foaming agents
Study results:
▪ Density according to mixing ratios of foaming agents appeared in the similar range with 31㎏/㎥ or more. Compression strength failed to meet KS M 3808 foaming polystyrene standards at 10:20:35:35% and 25:5:35:35%, and flexural destruction load was met at 3 ~ 41% comparing to that of standards In addition, moisture permeance was met at 9～63% compparing to that of standards.
▪ Initial thermal conductivity failed to met current KS M 3818 initial thermal conductivity standards at mixing ratios of 10:20:30:40%, 10:20:35:35%, 25:5:30:40% and 25:5:35:35%, whereas long-term thermal conductivity met KS M 3808 standards at 10:20:20:50%, 15:15:20:50%, 15:15:25:45%, 20:10:20:50% and 20:10:25:45%.
▪ As a result of analysis on compression strength, flexural destruction load, thermal conductivity (initial and long-term), moisture permeance and combustibility of insulators according to mixing ratios of foaming agent, they appeared to be higher at 15:15:20:50% with the cell size at 0.31mm and 20:10:20:50% with the cell size of 0.33mm than those of KS M 3808 standards.
▪ Mixing ratios of foaming agents for extrusion insulators using CO₂ were considered applicable at 15:15:20:50% and 20:10:20:50% in consideration of stability of thermal conductivity.

Study contents: ▪ Suggestions for the related specifications revision (draft) for policy suggestions using environmentally friendlyhigh-per formance insulators
Study results:
We suggest a plan to activate substitutional foaming agent materials as the international trend, not as the restriction standards, by applying the types of KS M 3808 standards to Type A (things not using freons but using hydrocarbon or carbon dioxide as a foaming agent) and Type B (using freons as a foaming agent).