JPH0441584A - Process for producing oil absorptive material - Google Patents

Abstract

PURPOSE:To obtain an oil absorptive material which is excellent in oil keeping property after oil absorption without dripping by infiltrating a monomer component which comprises two kinds of specific monomers into a hydrophobic and porous base to be adhered thereto and dipping the resultant base into a hot water bath to polymerize the monomer component. CONSTITUTION:90 to 99.999wt.% of a monomer mainly comprising a monomer having a solubility parameter value of 9 or less and having one polymerizable unsaturated group in the molecule, such as methyl acrylate, is mixed with 10 to 0.001wt.% of a crosslinking monomer having two or more polymerizable unsaturated groups in the molecule, such as ethylene glycol diacrylate, so that the sum of them amounts to 100wt.%. Then, the resultant monomer component is infiltrated into a hydrophobic and porous base such as polypropylenic nonwoven fabric and is adhered thereto. An oil absorptive material is obtained by dipping the resultant base into a hot water bath to polymerize the monomer component and produce an oil absorptive crosslinked polymer. This oil absorptive material is suitable for the recovery of thin-film oil floating on the surface of water and the like.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for manufacturing an oil absorbent material.

In more detail, oil in an oil-water mixture system or floating on the water surface.
ii selectively and efficiently absorbs oil even in membranous membranes,
Moreover, the present invention relates to a method for producing an oil absorbing material which has excellent oil retention performance for absorbed oil, has good oil recovery efficiency since there is no re-release of absorbed oil (liquid dripping, etc.), and is easy to perform post-treatment such as incineration.

(Prior Art) In recent years, the recovery of oil spilled onto the sea and oil content from wastewater has become a major problem in terms of environmental conservation.

In addition, there is a strong desire for a simple method for disposing of small-scale waste oil disposed of in homes and factories, as well as oil leaks such as machine oil in factories.

One of the effective methods for recovering the oil content in these spilled oils and wastewater, or for treating waste oil and oil leaks, has traditionally been the method of adsorbing the oil with an oil-absorbing material and then incinerating or other post-treatment. . As such oil-absorbing materials, synthetic resin-based oil-absorbing materials made of hydrophobic fibers such as polyglobylene fibers, polystyrene fibers, and polyethylene fibers, and nonwoven fabrics thereof, have been used.

However, conventional synthetic resin oil-absorbing materials have an oil-absorbing effect that relies on adsorbing and retaining oil in the voids present in the oil-absorbing material.
It had the following drawbacks.

■ Poor oil retention performance after oil absorption; virtually no oil retention ability for low viscosity oil; and even for viscous oil, the absorbed oil is easily re-released by slight external pressure. As a result, liquid bleeds easily occur, and post-processing becomes extremely complicated.

■ When applied to the recovery of oil in an oil-water mixture or thin film of oil floating on the water surface, the oil recovery rate is poor, and since it also absorbs a large amount of water, the oil-absorbing material sinks into the water and is difficult to recover. Otherwise, inconveniences may arise in incineration after collection.

(Problem M to be Solved by the Invention) The present invention solves the above-mentioned problems that conventional oil absorbing materials have.

In other words, the object of the present invention is to selectively and efficiently absorb oil even in the case of oil in an oil-water mixture system or thin film oil floating on the water surface, and to have excellent oil retention performance for the absorbed oil and to retain the oil once absorbed. It is an object of the present invention to provide a method for producing an oil absorbing material with good reproducibility by an industrially simple operation, which has good oil recovery efficiency since there is no re-release (liquid dripping, etc.), and which is easy to perform post-treatments such as incineration.

(Means and effects for solving the problem) The present inventors have developed an oil-absorbing property produced by polymerization by polymerizing a specific monomer component attached to a hydrophobic porous base material under specific conditions. The cross-linked polymer can be evenly and firmly supported on the hydrophobic porous base material, and the oil-absorbing material made by supporting this oil-absorbing cross-linked polymer on the hydrophobic porous base material has excellent oil absorption and oil retention performance. We have found that this is extremely superior, and have completed the present invention.

That is, the present invention has a solubility parameter (SP value) of 9.
90 to 99.999% by weight of monomer (A) having one polymerizable unsaturated group in the molecule consisting of the following monomers as main components and at least two polymerizable unsaturated groups in the molecule. A monomer component consisting of 0.001 to 1011% by weight of crosslinkable monomer (B) (however, the total of monomers (A) and (B) is 100% by weight) is added to a hydrophobic porous base material. The oil-absorbing crosslinked polymer is applied to a hydrophobic porous substrate by impregnating and adhering the oil-absorbing crosslinked polymer to a hydrophobic porous substrate, and then immersing the substrate with the monomer component attached in a hot water bath to polymerize the monomer component. The present invention relates to a method for manufacturing an oil-absorbing material in which the oil-absorbing material is supported.

Solubility parameter (SP value) is generally used as a measure to express the polarity of a compound, and in the present invention, Sma
The value derived by substituting Hoy's cohesive energy constant into the formula for ll is applied, and the unit is (cal1 country 3)
! /2.

The monomer constituting the main component of the monomer (A) used in the present invention is a monomer having a solubility parameter (SP value) of 9 or less and one polymerizable unsaturated group in the molecule. . If a monomer with a solubility parameter (SP value) exceeding 9 is used as the main component of monomer (A), the monomer component may not be sufficiently impregnated into the hydrophobic porous substrate, or the obtained product may not be obtained. This is not preferable because the oil absorption performance of the oil absorbing material will be significantly reduced.

Examples of monomers having a solubility parameter (SP value) of 9 or less and one polymerizable unsaturated group in the molecule include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and t- Butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, phenyl (meth)acrylate, octylphenyl (meth)acrylate, nonylphenyl ( Unsaturated carboxylic acid esters such as meth)acrylate, dinonylphenyl(meth)acrylate, cyclohexyl(meth)acrylate, menthyl(meth)acrylate, dibutyl maleate, didodecyl maleate, dodecyl crotonate, didodecyl itaconate; di)butyl (meth)acrylamide, (di)dodecyl (meth)acrylamide, (
(Meth)acrylamide having a hydrocarbon group such as di)stearyl(meth)acrylamide, (di)butylphenyl(meth)acrylamide, (di)octylphenyl(meth)acrylamide; 1-hexene, 1-octene, isooctene, 1 α-olefins such as nonene, 1-decene, 1-dodecene; alicyclic vinyl compounds such as vinylcyclohexane; allyl ethers with aliphatic hydrocarbon groups such as dotesyl allyl ether; vinyl caproate, vinyl laurate, palmitin Vinyl esters with aliphatic hydrocarbon groups such as vinyl acid and vinyl stearate; vinyl ethers with aliphatic hydrocarbon groups such as butyl vinyl ether and dodecyl vinyl ether; aromatic vinyl compounds such as styrene, t-butylstyrene, and octylstyrene, etc. These monomers can be used alone or in combination of two or more. Among these, monomers having at least one aliphatic hydrocarbon group having 3 to 30 carbon atoms are preferred as monomers that uniformly adhere to the hydrophobic porous substrate and provide particularly excellent oil absorption and oil retention performance. and at least one unsaturated compound (a ) is particularly preferred.

The amount used in the monomer (A) having a solubility parameter (SP value) of 9 or less is 50% by weight or more, more preferably 70% by weight or more based on the total amount of the monomer (A). This is the ratio. If the amount of the monomer having a solubility parameter (SP value) of 9 or less in the monomer (A, ) is less than 50% by weight, an oil-absorbing material with poor oil-absorbing performance and oil-retaining performance cannot be obtained.

Therefore, in the present invention, it is necessary that the monomer (A) contains 50% by weight or more of a monomer having a solubility parameter (SP value) of 9 or less. A monomer having a solubility parameter (SP value) exceeding 9 may be contained in a proportion of 1% or less. Examples of such monomers include (meth)acrylic acid, acrylonitrile,
Maleic anhydride, fumaric acid, hydroxyethyl (meth)
Examples include acrylate, polyethylene glycol (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate.

Examples of the crosslinkable monomer (B) used in the present invention include:
Ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polyethylene glycol polypropylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate Acrylate, 13-
Butylene glycol di(meth)acrylate, neobentyl glycol di(meth)acrylate, 1,6-hexanethiol di(meth)acrylate, N,N-methylenebisacrylamide, NN-propylenebisacrylamide, glycerin tri(meth)acrylate , trimethylolpropane tri(meth)acrylate, tetramethylolmethanetetra(meth)acrylate, esterification of alkylene oxide adducts of polyhydric alcohols (e.g. glycerin, trimethylol 10 pan or tetramethylolmethane) with (meth)acrylic acid. Polyfunctional (meth)acrylates and di-vinylbenzene obtained by
One species or two or more species can be used.

In the present invention, monomer (A) and crosslinkable monomer (
The ratio of B) is the monomer (A) and the crosslinkable monomer (B).
The monomer (A) is in the range of 90 to 99.999% by weight, and the crosslinkable monomer (B) is in the range of 0.001 to 10% by weight.

If the monomer (A) is less than 90% by weight or the crosslinkable monomer (B) is more than 10% by weight, the crosslinking density of the oil-absorbing crosslinked polymer produced by polymerization will be too high, resulting in a large amount of oil. This is undesirable because the monomer (A
) exceeds 99.999% by weight or crosslinkable monomer (B)
If it is less than 0.001% by weight, the solubility of the oil-absorbing cross-linked polymer produced by polymerization in oil increases, and after oil absorption, the oil-absorbing cross-linked polymer desorbs and elutes from the hydrophobic porous base material, causing the oil-absorbing material to become indispensable. It is not desirable because it makes it impossible to perform its functions.

In order to facilitate the subsequent polymerization, the monomer components used in the present invention are generally mixed with a polymerization initiator and subjected to the impregnating and adhering step to a hydrophobic porous substrate. Such polymerization rwJ initiators include, for example, organic peroxides such as benzoyl peroxide, lauroyl peroxide, and cumene hydroperoxide; 2,2'-azobisisobutyronitrile, 2,2'-azobisdimethyl Examples include azo compounds such as valeronitrile. In addition, in order to facilitate the impregnation and adhesion of the monomer components, the monomer components are diluted with hydrophobic organic abrasion such as toluene or cyclohexane, or the monomer components are thickened with paraffin or a polymer compound. You can leave it there.

The hydrophobic porous base material used in the present invention has hydrophobicity to the extent that it does not dissolve or swell in water, preferably has high lipophilicity to adsorb oil, and has monomer There is no particular restriction as long as it is a porous base material that has a large surface area that can effectively support the oil-absorbing crosslinked polymer produced by polymerization of the components and voids that absorb and retain oil. A base material consisting of various materials can be used. Among these, preferred is a non-woven fabric or woven fabric made of at least one synthetic fiber selected from the group consisting of polyolefins such as polypropylene and polyethylene, polyester, nylon, and polyurethane, as it provides an oil-absorbing material with particularly excellent oil-absorbing performance. .

In the present invention, the method of impregnating and adhering the monomer component to the hydrophobic porous substrate is not particularly limited, and for example, known printing methods such as spraying, spraying, brushing, roller, or screen printing may be used. Examples include applying the monomer component using a hydrophobic porous substrate, or dipping a hydrophobic porous base material in the monomer component and then squeezing it out to a predetermined amount as necessary.

There is no particular restriction on the amount of the monomer component attached to the hydrophobic porous substrate, but the proportion should be in the range of 10 to 500 parts by weight per 100 parts by weight of the hydrophobic porous substrate. If the amount of the monomer component, which is preferably attached, is less than 10 parts by weight, the oil absorption and oil retention performance of the resulting oil absorbing material may be insufficient, which is undesirable. If the adhesion amount exceeds 500% by weight, the oil-absorbing cross-linked polymer produced by polymerization will fill the voids in the hydrophobic porous base material, resulting in a decrease in the oil-absorbing performance of the oil-absorbing material, which is undesirable.

In the present invention, in order to polymerize the monomer component attached to the hydrophobic porous substrate, it is necessary to immerse the hydrophobic porous substrate with the monomer component attached in a hot water bath for polymerization. If the polymerization is carried out in a polymerization atmosphere other than a hot water bath, such as in the air or in an inert scum, the polymerization will need to be controlled and the surface will become partially sticky, resulting in an oil-absorbing cross-linked polymer suitable as an oil-absorbing material. As a result, it becomes impossible to obtain an oil-absorbing material in which an oil-absorbing cross-linked polymer is supported on a hydrophobic porous base material with good reproducibility, and the sticky residue remaining in the obtained oil-absorbing material can be easily stored. This will cause problems in handling during use.

Polymerization conditions such as polymerization temperature and polymerization time when polymerizing in a hot water bath vary depending on the type and amount of the polymerization initiator or the type and composition of the monomer components, but generally the temperature is 40-100°C, preferably 50-100°C. The oil-absorbing material of the present invention can be obtained by keeping the base material to which the monomer component is attached in a hot water bath maintained at 95° C. for several minutes to several hours.

Moreover, more preferably, by bubbling an inert gas into a hot water bath to remove dissolved oxygen in the hot water bath, a more uniform oil absorbing material of the present invention can be obtained in a shorter time and more uniformly.

Although it is industrially preferable to use a hot water bath as the hot water bath used in the present invention, it may cause adverse effects such as elution of monomer components from the hydrophobic porous substrate or deterioration of the substrate. Organic thermal spraying such as ethylene glycol or a hot water bath mixed with various additives may be used as long as it does not cause any damage.

Further, the oil-absorbing material of the present invention thus obtained may be used as it is after being taken out of the hot water bath, but it may be used after drying if necessary.

Any method can be used for drying, such as hot air,
Examples include microwaves, infrared rays, and ultraviolet rays.

(Effects of the Invention) According to the production method of the present invention, it is possible to uniformly and firmly immobilize an oil-absorbing crosslinked polymer on a hydrophobic porous substrate by simply performing an industrially simple operation. Moreover, the oil-absorbing material obtained by the production method of the present invention has superior performance compared to conventional oil-absorbing materials.

That is, the oil absorbent obtained by the production method of the present invention is
Since it has an oil-absorbing mechanism in which the oil-absorbing crosslinked polymer further absorbs the oil adsorbed on the hydrophobic porous base material and swells, it exhibits the following excellent oil-absorbing performance compared to conventional oil-absorbing materials.

■ Excellent oil retention performance after oil absorption, no dripping, and post-treatment such as incineration is extremely easy.

■ Because it absorbs almost no water and only selectively absorbs oil, it is highly effective in recovering oil from oil-water mixed systems and thin oil films floating on the water surface.

Therefore, the present invention provides a method for producing an oil-absorbing material that is suitable for household waste oil treatment, industrial waste oil treatment, oil leak treatment, waste water treatment, and treatment of floating oil spilled into bits, ports, lakes, and the sea. It is extremely useful as a

(Example) Next, the present invention will be explained in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to L. shall represent the division.

Example 1 In a stainless steel vat with a capacity of 1.9 J, nonyl phenyl acrylate (SP value: 8.3>9
A solution consisting of 9.794 parts of 1,6-hexanediol diacrylate as a crosslinkable monomer (B) and 0.206 parts of benzoyl peroxide as a polymerization initiator was charged.

Then, in this solution, a polypropylene nonwoven fabric cut into 20cm x 15cm pieces (basis weight 200t/rr?) was added.

After dipping the sample with a bulk density of 0.1 trl (3), it was pulled up and squeezed using a simple roller. The amount of the monomer solution deposited at this time was 100 parts per 100 parts of the polypropylene nonwoven fabric.

Thereafter, the polypropylene nonwoven fabric to which this monomer solution was attached was immersed in a hot water bath (warm water) maintained at 80°C under nitrogen bubbling for 2 hours, and then further heated to 90°C and kept open at the same temperature for 2 hours. Polymerization was carried out. Oil absorbent material (1) was obtained by drying the polypropylene nonwoven fabric taken out of the hot water bath at 100° C. for 1 hour in a hot air dryer.

Example 2 In Example 1, 49°930 parts of hexadecyl methacrylate (SP value near, 8) and N-octyl methacrylamide (SP value: 8.6>49) were used as monomers (A>).
．． An oil absorbent material (2) was obtained in the same manner as in Example 1, except that 930 parts of divinylbenzene was used instead of 930 parts of divinylbenzene as the crosslinkable monomer (B). The amount of the monomer solution deposited at this time was 100 parts per 100 parts of the polypropylene nonwoven fabric.

Example 3 In Example 1, dodecyl acrylate (SP value: 7.9>55.704 parts and N
, N-dioctyl acrylamide (SP value: 8.2) 3
7.136 parts, polypropylene glycol dimethacrylate (molecular weight 4000) as crosslinkable monomer (B)7.
An oil-absorbing material (3) was obtained in the same manner as in Example 1 except that 160 parts was used instead. The amount of monomer solution deposited at this time is 1 part per 100 parts of polypropylene nonwoven fabric.
The ratio was 0.00 parts.

Example 4 In Example 1, 99.823 parts of dodecyl acrylate (SP value near, 9) was used as the monomer (A), and 0.823 parts of ethylene glycol diacrylate was used as the crosslinkable monomer (B).
An oil absorbent material (4) was obtained in the same manner as in Example 1 except that 177 parts was used instead. The amount of monomer solution deposited at this time is 1 part per 100 parts of polypropylene nonwoven fabric.
The ratio was 0.00 parts.

Example 5 In Example 1, the monomers (A) were 54.881 parts of t-butylstyrene (SP value = 7°9), 44.903 parts of 1-dezene (SP value near, 0), and a crosslinkable monomer. Quantity (
Oil absorbent material (5) was prepared in the same manner as in Example 1, except that 0.216 parts of divinylbenzene was used instead of B).
I got it. The amount of the monomer solution deposited at this time was 100 parts per 100 parts of the polypropylene nonwoven fabric.

Example 6 In Example 1, nonylphenyl acrylate (SP value: 8.3>74°793 parts) and hydroxyethyl acrylate (SP value: 10.3) were used as the monomer (A).
) 24.931 parts, 1.6- as crosslinkable monomer (B)
The oil-absorbing material (
6) was obtained.

The amount of the monomer solution deposited at this time was 100 parts per 100 parts of the polypropylene nonwoven fabric.

Example 7 In Example 4, polyester nonwoven fabric (basis weight 200 t/d) was used instead of polypropylene nonwoven fabric.

An oil-absorbing material (7) was obtained in the same manner as in Example 4, except that a bulk density of 0 and Ig/■5) was used. The amount of the monomer solution deposited at this time was 200 parts per 100 parts of the polyester nonwoven fabric.

Example 8 Nylon nonwoven fabric cut into 20×151 pieces (basis weight 20
0g/I, bulk density 0.1sr/■3) and monomer (A> dodecyl acrylate (SP value near, 9) 99.8
A solution consisting of 23 parts of ethylene glycol diacrylate, 0.177 parts of ethylene glycol diacrylate as a crosslinkable monomer (B), and benzoyl peroxide as a polymerization initiator was uniformly sprayed using a sprayer. The amount of the monomer solution deposited at this time was 50 parts per 100 parts of the nylon nonwoven fabric.

Thereafter, the nylon nonwoven fabric to which this monomer solution was attached was immersed in a hot water bath (warm water) kept at 80°C under nitrogen bubbling for 2 hours, then further heated to 90°C, and maintained at the same temperature for 2 hours. Polymerization was performed. The nylon nonwoven fabric taken out of the hot water bath was dried in a hot air dryer at 100°C for 1 hour to obtain an oil absorbent material (8).

Comparative Example 1 In Example 1, 89.820 parts of dodecyl acrylate (SP value: 7.9) was used as the monomer (A), and 1 ethylene glycol diacrylate was used as the crosslinkable monomer (B).
A comparative oil absorbent material (1) was obtained in the same manner as in Example 1 except that 0.180 part was used instead. The amount of the monomer solution deposited at this time was 100 parts per 100 parts of the polypropylene nonwoven fabric.

Comparative Example 2 In Example 1, 39.854 parts of dodecyl acrylate and methacrylic acid (SP value:
10.1) Comparative oil-absorbing material (2) was obtained in the same manner as in Example 1, except that 59.780 parts and 0.366 parts of ethylene glycol diacrylate were used as the crosslinkable monomer (B). Ta. The amount of the monomer solution deposited at this time was 100 parts per 100 parts of the polypropylene nonwoven fabric.

Comparative Example 3 A comparative oil-absorbing material (3) was obtained in the same manner as in Example 4, except that ethylene glycol diacrylate as the crosslinkable monomer (B) was not used. The amount of the monomer solution deposited at this time was 100 parts per 100 parts of the polypropylene nonwoven fabric.

Comparative Example 4 A polypropylene nonwoven fabric coated with the same monomer solution as obtained in Example 1 was placed in a hot air dryer kept at 80°C under a nitrogen atmosphere, heated at 80°C for 2 hours, and then dried at 90°C. Comparative oil absorbent material (4) was obtained by increasing the temperature to 100% and maintaining the same temperature for 2 hours to carry out polymerization. When this comparative oil-absorbing material (4) was compared to the oil-absorbing material (1) obtained in Example 1 by touch, stickiness remained in some parts and non-uniformity of polymerization was observed.

Example 9 (Oil absorption performance test) Oil absorbing materials (1) to (8) obtained in Examples 1 to 8, comparative oil absorbing materials (1) to <4> obtained in Comparative Examples 1 to 4, and Example 1 Each of the same polypropylene nonwoven fabrics used in Example 1 was cut into 10 x 101 pieces, and each of the cut samples was immersed in gelosin or spindle oil at 20°C. After 24 hours, lift the sample, clamp the sample with clips, and leave it hanging in the air for 30 minutes to allow the oil not retained in the sample to flow down sufficiently. Measure the weight of the sample, and hold it on the oil absorbing material according to the following formula. Calculate the amount of oil absorbed (oil absorption amount).

Oil absorption amount (g) = weight of sample after oil absorption - weight of sample before immersion The results are shown in Table 1.

Example 10 (i-oil performance test) Each of the oil-absorbed samples obtained in Example 9 was placed on a 200-mesh wire mesh, and a load of 10 kg/cd was applied to the sample.
The amount of oil flowing out at that time was measured, and the oil retention rate after weight was calculated according to the following formula.

Oil retention rate (%) = ((oil absorption amount - spilled oil amount) / oil absorption amount) x 1
00 (The oil absorption amount (g) is calculated using the formula % in Example 9.
) The results are shown in Table 1.

Table 1 Example 11 (Floating oil recovery test) 30j of water in a water tank with a capacity of 361 (area of water surface = 1350
cd) and then add 15g of heavy oil A to the water surface.
On this water surface, the oil absorbing materials (1) to (1) obtained in Examples 1 to 8 are
8) and comparative oil absorbing materials (1) obtained in Comparative Examples 1 to 4.
(4) and samples of the same polypropylene nonwoven fabric used in Example 1 cut into 10 cm x 10 cm were floated for 4 hours and then pulled up. Based on the residual A heavy oil on the water surface, the floating oil recovery ability was evaluated according to the following criteria. evaluated.

○: No heavy oil A remains on the water surface.

Δ: Heavy oil A is slightly scattered on the water surface.

×: A considerable amount of heavy oil A remains on the water surface.

The results are shown in Table 2.

Claims (1)

[Claims] 1. Monomer (A) having one polymerizable unsaturated group in the molecule, which is mainly composed of a monomer with a solubility parameter (SP value) of 9 or less, from 90 to 99.999. Weight% and crosslinkable monomer (B) having at least two polymerizable unsaturated groups in the molecule 0.001 to 10% by weight (however, monomer (A)
and (B) (total of 100% by weight) is impregnated onto a hydrophobic porous substrate, and then the substrate with the monomer component attached is immersed in a hot water bath. A method for producing an oil-absorbing material in which an oil-absorbing crosslinked polymer is supported on a hydrophobic porous base material, the method comprising polymerizing a monomer component. 2. Monomer (A) has at least one aliphatic hydrocarbon group having 3 to 30 carbon atoms, and alkyl (meth)acrylate, alkylaryl (meth)acrylate, alkyl (meth)acrylamide, alkylaryl 2. The method for producing an oil absorbing material according to claim 1, wherein the main component is at least one unsaturated compound (a) selected from the group consisting of (meth)acrylamide, alkylstyrene, and α-olefin. 3. Monomer (A) is the unsaturated compound (a) according to claim 2
3. The method for producing an oil-absorbing material according to claim 1, wherein the monomer (A) contains 50% by weight or more of the following. 4. The method for producing an oil-absorbing material according to claim 1, wherein the hydrophobic porous base material is a nonwoven or woven fabric of at least one synthetic fiber selected from the group consisting of polyolefin, polyester, nylon, and polyurethane.