What is the chemical resistance of Rogers foam?
The chemical resistance of Rogers foam is not a single fixed attribute, but highly depends on the composition of the substrate, the design of molecular structure of the specific product series, and the types of chemical media (such as solvents, oils, acids and alkalis, detergents, etc.). Different series of Rogers foam have different optimization directions for chemical tolerance, so it is necessary to judge its applicability in combination with specific scenarios. The following is a detailed explanation from three dimensions: classification characteristics of substrates, tolerance performance of typical chemical media and application precautions:
1. Basic differences between core substrate series and chemical resistance
The mainstream product series of Rogers foam shows significant differences in chemical resistance due to different base materials, which is the core premise to judge its chemical tolerance.
The core characteristics of chemical resistance of core substrate of product series are applicable to the scene direction.
PORON® polyurethane (PU) has moderate chemical resistance and good tolerance to polar solvents (such as water and alcohol) and weak acid and alkali (pH 4-9). Sensitive to strong solvents (such as toluene and acetone), strong acid and alkali, and petroleum solvents, and prone to swelling, softening or performance degradation. Consumer electronics, medical equipment (contact with mild detergent)
BISCO® Silicone) rubber has excellent chemical resistance, especially high-temperature oil, strong oxidant and most acids and bases (except concentrated strong acid/fluoride), and is extremely stable to water, steam, ozone and ultraviolet rays. It slightly swells some nonpolar solvents (such as n-hexane), but it does not affect the core properties. Automobile power system, industrial high-temperature equipment
FOAM-4000® polyethylene (PE) has stable chemical resistance, excellent resistance to most solvents (alcohols, esters, weak acids and bases) and oils (mineral oil and vegetable oil), and is insoluble in water and most organic solvents. Weak tolerance to strong oxidizing acids (such as concentrated nitric acid) and halogenated hydrocarbons (such as carbon tetrachloride). Industrial seal, rail transit (contact with lubricating oil)
HT-800 chloroprene rubber (Cr) has good oil resistance (especially mineral oil) and weather resistance, and good tolerance to weak acid, weak alkali, water and alcohol. Sensitive to strong solvents (such as benzene and ketone) and strong oxidizing reagents, easy to age and harden. Automobile chassis, outdoor industrial equipment
Second, the tolerance performance of typical chemical media (scene description)
In view of the common chemical media in industrial scenes, combined with the actual performance of Rogers mainstream foam series, the applicable boundary can be further defined:
1. Water and polar solvent (the most common contact medium)
Tolerance: almost all Rogers foams have good water resistance, and will not be obviously absorbed, dissolved or degraded after long-term immersion (such as tap water at 25℃); PORON®, BISCO® and FOAM-4000® are stable to polar solvents such as medical alcohol (75% ethanol), isopropanol, ethylene glycol, etc., and only the surface may be slightly wet without swelling or cracking.
Exceptions: some low-hardness PORON® (such as 20-30 Shore OO) may have slight hardness changes after long-term contact with high-concentration alcohol (> 95%), but the buffering and sealing function will not be affected; HT-800® of polychloroprene rubber substrate should be dried after contact with water to avoid slight mildew caused by long-term humidity (additional mildew prevention treatment is needed).
2. Oils and lubricants (automobile and industrial core scenes)
Mineral oil/engine oil: BISCO® silicone rubber foam shows the best performance, and can be exposed to mineral oil and engine oil for a long time at-40℃~150℃, without swelling, oiling or performance degradation (in line with TL-VW 52625 and other standards of automobile industry); FOAM-4000® polyethylene foam takes the second place, and there is no obvious change in short-term contact, and slight volume expansion (< 5%) may occur in long-term (> 1000 h), which will not affect the sealing; PORON® polyurethane foam is sensitive to mineral oil, which is easy to soften, swell and even lose elasticity after contact. It is strictly prohibited to use it in the scene of direct contact with oil.
Vegetable oil/food-grade oil: FOAM-4000® meets the FDA food contact standard (21 CFR 177.1520), and is stable in tolerance to vegetable oil and edible oil, with no migration; BISCO® medical grade silicone rubber foam can also be tolerated, but the specific model of food contact certification needs to be confirmed.
3. Acid-base medium (industrial cleaning and medical disinfection scene)
Weak acid and alkali (pH 4-10, such as citric acid and baking soda solution): All series perform well. PORON®, BISCO® and FOAM-4000® have no corrosion or performance change after long-term contact (such as daily cleaning). It is suitable for surface disinfection of medical equipment (such as wiping with weak acid disinfectant) and mild cleaning of industrial equipment.
Strong acid and alkali (pH < 2 or pH > 12, such as concentrated hydrochloric acid and sodium hydroxide solution): only BISCO® silicone rubber foam can endure for a short time (such as occasional splashing), but long-term contact will lead to surface aging; PORON®, FOAM-4000® and HT-800® are all sensitive, and will swell, decompose or suddenly drop in strength after contact, so they are strictly prohibited.
4. Strong solvents (industrial painting and printing scenes)
Non-polar solvents (such as toluene, xylene, gasoline, n-hexane): Almost all Rogers foams are sensitive, PORON® will swell and soften rapidly, and FOAM-4000® may crack. BISCO® silicone rubber foams will lose their elasticity although their swelling degree is low, so contact is not recommended.
Strong polar solvents (such as acetone and ethyl acetate): PORON® and HT-800® are extremely resistant, and they deform within a few seconds after contact; BISCO® and FOAM-4000® can be exposed briefly (e.g. wiped in a few seconds), but long-term exposure will still lead to performance degradation, so continuous exposure should be avoided.
Three, the key points for attention in the application
Give priority to the official technical documents: Rogers provides a Chemical Resistance Guide (such as PORON®'s Technical Data Sheet (TDS)) for each foam series, clearly indicating the "tolerance level" of the series to specific chemical media (such as "excellent/good/limited/not recommended"), and consulting the corresponding documents in combination with the actual contact media type, concentration, temperature and contact duration before selecting the type, so as to avoid judging by experience only.
Considering the superimposed influence of environmental temperature: temperature will significantly aggravate the corrosion of chemical media on foam-for example, BISCO® can tolerate mineral oil at 25℃, but at 180℃, mineral oil will accelerate its aging; Therefore, it is necessary to confirm whether the "temperature resistance range" and "chemical resistance" of foam meet the application environment.
Verification of small batch test: If the application scenario involves special chemical media (such as customized cleaning agents and industrial additives), it is recommended to take a small amount of foam samples and simulate the actual contact conditions (temperature, duration and media concentration) for testing, and observe whether the samples have swelling, discoloration, hardness change, elastic attenuation and other problems before deciding whether to use them in batches.
Avoid "multi-media mixed contact": some chemical media can be tolerated when contacted alone, but more corrosive substances may be produced after mixing (such as alcohol mixed with some detergents may produce acidic substances), so the influence of mixed media should be evaluated in advance.
summary
The chemical resistance of Rogers foam is characterized by "significant difference and strong scene dependence": silicone rubber substrate (BISCO®) is the best in oil resistance, high and low temperature resistance and weak acid and alkali resistance; Polyethylene substrate (FOAM-4000®) has more advantages in solvent resistance and food-grade scenes. Polyurethane substrate (PORON®) is only suitable for mild environment (such as water and alcohol). The four elements of "medium type-concentration-temperature-contact time" should be closely followed in the selection, and the long-term stability of foam in chemical contact scenarios can be ensured by combining official documents with actual tests.
