JPH0363563B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for sulfonating polyolefins having a large specific surface area, such as polyolefin powders or fibers. A method of sulfonating polyolefin in fuming sulfuric acid is known, but it is difficult to obtain a homogeneous sulfonated product for polyolefin powders or fibers that have a large surface area relative to their weight, that is, have a large specific surface area. Have difficulty. The reason for this is that polyolefins are hydrophobic and have poor water wettability, so if they have a shape with a large specific surface area, they cannot be treated uniformly over the entire surface with fuming sulfuric acid. In particular, fine powder polyolefin is
Generally, because of secondary agglomeration, it is difficult for the fuming sulfuric acid to immerse the entire surface of the particles, even between the particles. As a result of conducting research to resolve the difficulties in the above-mentioned conventional methods, the present inventor discovered that before reacting polyolefins in oleum, a cationic surfactant or HLB (hydrophilic-lipophilic balance) was used.
It was discovered that an extremely homogeneous sulfonated product can be obtained by treatment with a nonionic surfactant having a sulfonate of 10 to 18, leading to the completion of the present invention. That is, in the present invention, when polyolefin having a specific surface area of 100 cm ² /g or more is sulfonated in oleum, a cationic surfactant or
This is a method for sulfonating a polyolefin, which is characterized in that a polyolefin treated with a nonionic surfactant having an HLB of 10 to 18 is dispersed in fuming sulfuric acid containing 1 to 20% as SO ₃ and reacted. In the present invention, polyolefin refers to polyethylene, polypropylene, polybutene, a copolymer of two or more olefins such as ethylene, propylene, butene, hexene, vinyl chloride, or a product made of two or more of these polymers. It is a mixture. The present invention is effective for materials with a large specific surface area such as polyolefin powder or fibers, generally those with a specific surface area of 100 cm ² /g or more, and particularly for materials with a specific surface area of 300 cm 2 /g or more.
cm ² /g or more, if particles, fibers, etc. are secondary agglomerated or associated, or if the surface has a complicated shape when observed under a microscope, the method of the present invention can be used for the first time to make it homogeneous and hydrophilic. It can be a product with In the present invention, the surfactants used to pre-treat polyolefins have significant surface activity at low concentrations, have hydrophilic groups and lipophilic groups, and are stable in strong acids, such as higher amine halogenates,
Cationic surfactants such as quaternary ammonium salts and alkylpyridinium halides, and polyethylene glycol alkyl ethers with HLB of 10 to 18.
A nonionic surfactant having an HLB of 10 to 18 is particularly preferred, as is clear from the examples below. The treatment of polyolefin with the above surfactant is carried out by impregnating the polyolefin with an alcoholic solution of the surfactant and then drying and removing the alcohol. Contained in fuming sulfuric acid
The amount of SO ₃ is 1 to 20%, and if it exceeds 20%, it is not appropriate because the degree of sulfonation of the product tends to vary and is difficult to control, and the product tends to be colored. If the amount of SO ₃ is less than 1%, it is not preferable because sulfonation takes a long time. The sulfonated polyolefin according to the present invention is useful as a filler for columns, etc., and as a material for sintered bodies, and is particularly effective in fields where precision is required, such as microfilters, printing rolls, foam plates, etc. be. A product with low uniformity of sulfonation cannot be used as a product in a field that requires high precision as described above, and this can only be achieved with the uniformly sulfonated product of the present invention. Sulfonated polyolefin is usually made into a product by neutralizing it with an alkaline aqueous solution such as caustic soda or ammonia, but the product of the present invention exhibits high hydrophilicity and the polyolefin itself is hydrophobic, making it resistant. Because of its high chemical properties, it does not absorb water and swell like conventional hydrophilic polymers.
There is no possibility that the molded product will deform,
Stable functionality can be maintained for a long period of time. Next, examples of the present invention will be described. Examples After the polyolefin products shown in the table are immersed in a 3% methanol solution of the various surfactants shown in the table, the solvent is removed by drying under reduced pressure. The oleum reaction solution was prepared by diluting commercially available oleum (SO ₃ 28%), and the SO ₃ content was calculated from the degree of dilution. The polyolefin is added to this reaction solution and allowed to react at room temperature for the time shown in the table. The results were as shown in the table.

【table】

[Table] In the above table, the specific surface area was calculated from the density of the product by measuring the required size of particles and fibers by microscopic observation and assuming that the surface was smooth. The exchange equivalent was calculated as follows. A sulfonated sulfonic acid (-SO ₃ H) type polyolefin product (Wg) is taken, immersed in a 1N aqueous solution of calcium chloride to reach an equilibrium state, and the hydrogen chloride generated in the aqueous solution is dissolved in 0.1N caustic soda. It was titrated with an aqueous solution (potency f) to determine the neutralization value (xcc) with phenolphthalein, which was calculated using the following formula. Exchange equivalent = 1/10・f・x/W (milliequivalent/gram) When used for applications that do not require ion exchange ability, sulfonate [-SO ₃ M (M
represents Na, K, Ca, Mg, _NH4, etc.)] type. Water wettability was measured using powder molded products, fibers, and resin pieces (pellets). Powder molded products are
Approximately 22 g of powder was uniformly filled into an aluminum mold that would yield a molded product with a thickness of 5 mm and a diameter of 100 mm.
It is molded by heating for about 20 minutes at a temperature near the softening point of each resin. Water was dropped onto this powder molded product and judgment was made based on the water absorption rate.The fibers and resin pieces (pellets) were gently floated on the water surface and judgment was made based on the contact angle and the degree of sinking into the water. In addition, in the table, the following symbols indicating the degree of water wettability are used. ◎……Absorbs instantly, ○…Absorbs in about 10 seconds, △
...Absorbed in about 30 seconds, ×...Not absorbed at all.

Claims (1)

[Claims] 1. When sulfonating a polyolefin with a specific surface area of 100 cm ² /g or more in oleum, the polyolefin, which has been previously treated with a cationic surfactant or a nonionic surfactant with an HLB of 10 to 18, is converted into SO ₃ with 1 A method for sulfonating polyolefin, which comprises dispersing and reacting in fuming sulfuric acid containing ~20%.