JPH10249193A - Water absorbing resin and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reutilize scrap as a high molecular material as well as to obtain a water absorbing resin excellent in water absorbing property by introducing ionic groups into a high molecular material contg. an inorg. pigment, a powdery metallic pigment and acrylonitrile. SOLUTION: Ionic groups are introduced into a high molecular material contg. an inorg. pigment, a powdery metallic pigment and acrylonitridle to obtain the objective water absorbing resin. The acrylonitrile unit content is 5-80mol%, preferably about 10-60mol%. The constituent units of the high molecular material except the acrylonitrile units re styrene or conjugated diene (butadiene or isoprene) units and the content is 20-95mol%, preferably about 40-85mol%. The amt. of the pigments is 0.01-20wt.%, preferably about 0.05-10wt.%. The ionic groups are introduced by 5-95mol%, preferably about 10-70mol% of the amt. of all the units.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water-absorbent resin obtained by modifying a polymer material containing acrylonitrile, and a method for producing the same.

[0002]

2. Description of the Related Art Examples of resins containing acrylonitrile include polystyrene resins such as ABS resin (acrylonitrile-butadiene-styrene resin), SAN resin (styrene-acrylonitrile resin), and AAS resin (acrylonitrile-acryl-styrene resin). Resin and N
And a synthetic rubber of BR rubber (acrylonitrile-butadiene rubber). These resins are relatively inexpensive, and in particular, the former polystyrene-based resin has excellent properties such as rigidity, dimensional stability, and workability. It is widely used as a resin material for various component materials. The latter synthetic rubber is widely used as tubes, hoses, and various cushioning materials.

[0003] Under such circumstances, these polymer materials are expected to be further expanded in use, and it is desired to consider a modification to a material having higher added value.

[0004] In addition, products using the above-mentioned polymer materials are generated in large quantities as waste materials with an increase in production volume. In recent years, the amount of waste materials composed of these polymer materials has also been increasing, and the need for effective use of waste materials has been increasing due to the increasing interest in global environmental conservation.

[0005]

By the way, waste materials made of polymer materials are generally roughly classified and treated by three kinds of methods of landfill, incineration and remelting. In Japan, landfill and incineration account for about 90% of the total, and at present it is hardly recycled.

[0006] As for recycling of waste materials, generally, heating and melting and re-forming (however, only a thermoplastic resin) are performed. However, deterioration of quality due to heat (lower molecular weight, oxidation of resin, etc.), mixing of foreign matter such as dust, or mixing of resins containing various colorants, inorganic pigments serving as reinforcing agents, and metal powder pigments. There were many problems, such as the need for color matching. As described above, when the waste material is recycled by heating and melting, the processing technology and the processing cost have been serious obstacles.

Accordingly, an object of the present invention is to provide a water-absorbent resin excellent in water absorbency by modifying a polymer material containing acrylonitrile, and a method for producing the same.

Further, the present invention provides a polymer material comprising:
An object of the present invention is to provide a water-absorbent resin that can effectively use waste materials and a method for producing the same.

[0009]

Means for Solving the Problems The present inventors have intensively studied that the above-mentioned object is achieved, and as a result, inorganic pigments and metal powder pigments effectively act on the modification of acrylonitrile-containing polymer materials. And found that the present invention was completed.

That is, the water-absorbing resin according to the present invention that has achieved the above-mentioned object is characterized in that an ionic group is introduced into a polymer material containing an inorganic pigment and / or metal powder and acrylonitrile. .

The above-mentioned polymer material has the following structural units:
Since it contains an acrylonitrile unit, it does not show water solubility even if an ionic group is introduced. In a polymer material containing an acrylonitrile unit, the modified product exhibits water absorbability due to the hydrolysis of the nitrile portion of the acrylonitrile upon introduction of an ionic group.

The content of the acrylonitrile unit is 5
~ 80 mol%.

If the content of acrylonitrile is too small, the water absorbing effect is reduced, and the water-absorbing resin obtained after the introduction of the ionic group becomes water-soluble, so that it cannot be used as a water-absorbing resin. turn into. On the other hand, when the content of acrylonitrile is too large, the polymer material itself becomes hard, so that it becomes difficult to pulverize and the reforming reaction becomes difficult. In addition, when the content of acrylonitrile is too large, the content of styrene or conjugated diene, which is another constituent unit, becomes small, so that it becomes difficult to swell against an acid such as a solvent or a sulfonating agent, and introduction of an ionic group. Becomes difficult. For this reason, the water absorbing effect on the aqueous electrolyte solution, which is a practical requirement for the water absorbing resin, is reduced.

The structural units other than acrylonitrile of the polymer material include styrene and conjugated dienes (butadiene, isoprene). These constituent units introduce ionic groups (perform acid treatment or alkali treatment)
At this time, an ionic group (acidic group or alkali group) is introduced to improve water absorption.

In a polymer material containing an inorganic pigment and / or a metal powder pigment, the pigment tends to come off the surface of the material at the time of a reforming reaction, and a porous surface is generated to increase the reaction surface area. As a result, the reforming reaction is promoted. Subsequently, the porous surface is in a softened state as the reforming reaction is activated. For this reason, even the pigment present in the deeper part is desorbed from the same material, and the reforming reaction is further accelerated.

[0016] For such a reason, the modification reaction of the pigment-containing polymer material is promoted, and the surface of the polymer material after the modification is porous to a deep portion. Therefore, the water-absorbing resin obtained from this polymer material has a large water-absorbing area, and thus dramatically improves in terms of water absorption capacity and absorption speed.

The content of the above-mentioned inorganic pigment and / or metal powder pigment is 0.01 to 20% by weight, preferably 0.05 to 20% by weight.
-10% by weight.

When the content of the pigment is too small, the effect of accelerating the modification reaction of the polymer material becomes low. On the other hand, if the content of the pigment is too large, it becomes economically disadvantageous,
It becomes difficult to control the reforming reaction.

The polymer material may be a waste material made of a used resin molded for a specific use, to which the above-mentioned inorganic pigment and / or metal powder has been added in advance. Using waste materials as the polymer material is very effective from the viewpoint of environmental protection.

On the other hand, the method for producing a water-absorbent resin according to the present invention is characterized by introducing an ionic group into a polymer material containing an inorganic pigment and / or a metal powder pigment and acrylonitrile.

The amount of the ionic groups introduced is 5 to 95 mol% based on the polymer material.

The introduction of the ionic group may be carried out by alkali and / or acid treatment.

By reacting the alkali with the polymer material, the acrylonitrile portion and the conjugated diene portion undergo hydrolysis, and amide groups and hydroxyl groups are introduced, respectively. Further, by adding an alkali, the amide group is replaced with a carboxyl group or a salt thereof, and the hydroxyl group is replaced with a hydroxide salt.

Further, by reacting the acid with the polymer material, the acrylonitrile portion undergoes hydrolysis to introduce an amide group or a carboxyl group. On the other hand, a sulfonic acid group, -PO (OH) ₂ ,
An ionic group such as —CH ₂ PO (OH) ₂ and a nitro group is introduced.

In the acid treatment, for example, the polymer material is preferably dispersed in a sulfonating agent to introduce a sulfonic acid group. Specifically, at the time of acid treatment, it is preferable to first add either concentrated sulfuric acid or chlorosulfonic acid, and then add either sulfuric anhydride or fuming sulfuric acid.

The above-described modification treatment may be performed in an alkali or an acid, but the polymer material may be dispersed in a solvent to introduce an ionic group.

In the alkali and / or acid treatment, it is preferable to use a polymer material that passes through a mesh size of 3.5 mesh or more. By increasing the surface area of the polymer material, the area to be modified is increased, and the rate of introduction of ionic groups into the polymer material is improved.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments to which the present invention is applied will be described in detail.

The water-absorbing resin of the present invention is obtained by introducing an ionic group into a polymer material containing an inorganic pigment and / or a metal powder pigment and acrylonitrile.

The above-mentioned polymer material has the following structural units:
Since it contains an acrylonitrile unit, it does not show water solubility even if an ionic group is introduced. In a polymer material containing an acrylonitrile unit, the modified product exhibits water absorbability due to the hydrolysis of the nitrile portion of the acrylonitrile upon introduction of an ionic group.

The content of the acrylonitrile unit is 5
-80 mol%, preferably 10-60 mol%, more preferably 20-50%.

If the content of acrylonitrile is too small, the water absorbing effect is reduced, and the water-absorbing resin obtained after the introduction of the ionic group becomes water-soluble, so that it cannot be used as a water-absorbing resin. turn into.

On the other hand, if the content of acrylonitrile is too large, the polymer material itself becomes hard, so that it becomes difficult to pulverize and the reforming reaction becomes difficult. In addition, when the content of acrylonitrile is too large, the content of styrene or conjugated diene, which is another constituent unit, becomes small, so that it becomes difficult to swell against an acid such as a solvent or a sulfonating agent, and introduction of an ionic group. Becomes difficult. For this reason, the water absorbing effect on the aqueous electrolyte solution, which is a practical requirement for the water absorbing resin, is reduced.

The constituent units of the polymer material other than acrylonitrile include styrene and conjugated dienes (butadiene and isoprene). These constituent units introduce ionic groups (acidic groups or alkaline groups) when introducing ionic groups (perform acid treatment or alkali treatment) to improve water absorption.

The content of the constituent units other than acrylonitrile is at least one of styrene and conjugated diene in the range of 5 to 95 mol%, preferably 20 to 95 wt%, more preferably 40 to 85 mol%, more preferably Is 50 to 80 mol%.

In addition, if the polymer material contains styrene and conjugated diene in addition to acrylonitrile,
Further, another constituent unit may be included. These other structural units include maleic anhydride, itaconic anhydride, α-methylstyrene, (meth) acrylamide, (meth) acrylic acid, and (meth) acrylic acid ester (saturated and unsaturated having 1 to 10 carbon atoms). hydrocarbon ),
Examples include vinyl acetate, vinyl chloride, ethylene, propylene, butylene, vinyl pyrrolidone, vinyl pyridine and the like.

The weight-average molecular weight (Mw) of the waste material containing acrylonitrile is 1000 to 20.
000000, further 10,000-1,000,000
Is common. If the molecular weight is less than 1,000, the resulting resin will be water-soluble when subjected to the modification treatment, and a desired water-absorbing resin cannot be obtained. On the other hand, the molecular weight is 20,000
If it is larger than 000, the reforming treatment becomes difficult. However, when the polymer material is a waste material, the molecular weight is not particularly limited because a cross-link may be formed between the resins.

Specific examples of the acrylonitrile-containing polymer material used in the present invention include ABS resin (acrylonitrile-butadiene-styrene resin), SAN resin (styrene-acrylonitrile resin), and ASA resin (acrylonitrile-styrene-acrylate resin). ),
ACS resin (acrylonitrile-chlorinated polyethylene-
Styrene resin), AAS resin (acrylonitrile-acryl-styrene resin), NBR (acrylonitrile-butadiene rubber) and the like.

The above-mentioned polymer material may be a newly manufactured virgin material, or may be used for resin raw materials and discharged products (semi-products) in the production process of molded products, electric appliances, automobiles and the like. Waste materials that are used resins molded for a specific use, such as various component materials such as a molded housing and various cushioning materials such as tubes and hoses, may be used. The place of discharge may be any of factories, dealers, processes, etc., but those collected from factories or dealers are more likely to have relatively uniform compositions than general waste from homes. Therefore, it is more preferable.

The polymer material may be an alloy with another resin, and contains additives such as a face dye, a stabilizer, a flame retardant, a plasticizer, a filler, and other auxiliary agents. Waste materials may be used. Alternatively, it may be a mixture of a waste material that is a used resin and a virgin material.

The above-mentioned polymer material may be mixed with another different resin as long as the resin does not inhibit the modification treatment of the present invention. Examples include polyphenylene ether, polycarbonate, polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate, nylon, polyamide, polyester and the like. In addition,
These other different resins provide 6% of the total polymer material.
It is desirable that the content be 0% by weight or less. If the content of another different resin exceeds 60% by weight, the reaction of introducing ionic groups into waste material may be hindered.

Next, the polymer resin of the present invention is characterized by containing an inorganic pigment and / or a metal powder pigment.

In a polymer material containing an inorganic pigment and / or a metal powder pigment, the pigment tends to come off from the surface of the material at the time of the modification reaction, and a porous surface is generated to increase the reaction surface area. As a result, the reforming reaction is promoted. Subsequently, the porous surface is in a softened state as the reforming reaction is activated. For this reason, even the pigment present in the deeper part is desorbed from the same material, and the reforming reaction is further accelerated.

For the above reasons, the modification reaction of the pigment-containing polymer material is promoted, and the surface of the polymer material after the modification is in a porous state up to the deep portion. Therefore, the water-absorbing resin obtained from this polymer material has a large water-absorbing area, and thus dramatically improves in terms of water absorption capacity and absorption speed.

The content of the above-mentioned inorganic pigment and / or metal powder pigment is 0.01 to 20% by weight, preferably 0.05 to 20% by weight.
-10% by weight.

If the content of the pigment is too small, the effect of accelerating the modification reaction of the polymer material becomes low. On the other hand, if the content of the pigment is too large, it becomes economically disadvantageous,
It becomes difficult to control the reforming reaction.

These inorganic pigments and metal powder pigments include:
Those having good dispersibility with respect to the above-mentioned polymer materials are preferable, and carbon black, iron black, titanium oxide, zinc white, red iron, ultramarine, navy blue, cobalt blue, lithopone, zinc sulfide, antimony oxide, and yellow iron oxide , Amber, sienna, ocher, viridian, aluminum powder, brass powder, bronze powder and the like. Particularly, carbon black and titanium oxide are preferable.

The carbon black may be produced by any of a channel method, a furnace method and a thermel method, and may be used alone or in combination of two or more. In addition, as an average particle diameter, 5-500μ
m, preferably 10 to 50 μm.

Titanium oxide includes rutile type, anatase type,
Any type of long particulate titanium may be used, and each may be used alone or in combination of two or more. The average particle size is 0.01 to 50 μm, preferably 0.1 to 50 μm.
05 to 10 μm.

These inorganic pigments and metal powder pigments may be contained alone in the polymer material, or may be contained as a mixture of two or more kinds.

These inorganic pigments and metal powder pigments may be added to the above-mentioned polymer materials for the purpose of producing a water-absorbing resin, or may be a coloring agent, a hiding agent, a reinforcing agent,
The electric conductivity imparting agent may be added for another purpose, or may be used for both purposes.

As described above, the present invention relates to a waste material in which a pigment, such as a polystyrene resin product or a nitrile rubber product mass-produced as a general-purpose material, is added to a polymer material as a raw material in advance. This is very effective as a method for reusing these waste materials.
Therefore, from the viewpoint of environmental protection, it is preferable to use a waste material made of a resin used for the polymer material.

By the way, as the ionic group to be introduced,
Sulfonic acid, sulfonic acid salt, carboxyl group (carboxylic acid group), carboxylic acid salt, -PO (OH) ₂ , -PO (O
H) _{2 salt, -CH 2 PO (OH) 2} , -CH 2 PO (OH)
₂ salt, -NO _2, chloromethylated amine groups include chloromethylated amine salt. Among them, sulfonic acid,
Sulfonates, carboxylates and chloromethylated amine salts are preferred. These ionic groups may be used alone or two or more of them may be introduced.

As described above, the water-absorbing resin in which an ionic group has been introduced into a polymer material containing an inorganic pigment and / or metal powder and acrylonitrile promotes a reforming reaction by the pigment and has excellent water absorption. Water absorbent resin.

The introduction amount of the ionic group is 5 to 95 mol%, preferably 10 to 70 mol%, based on all units.

If the amount of the introduced ionic group is too large, the modified polymer material exhibits water solubility, and cannot be used as a water-absorbing resin. On the other hand, when the introduction amount of the ionic group is small, the water absorbing effect is reduced, and particularly, the water absorbing effect for the aqueous electrolyte solution is reduced.

Hereinafter, a method for producing a water-absorbing resin in which an ionic group is introduced into a polymer material containing the above-mentioned inorganic pigment and / or metal pigment and acrylonitrile will be described.

In the method for producing a water-absorbent resin to which the present invention is applied, a polymer material containing an inorganic pigment and / or a metal pigment and acrylonitrile is subjected to an alkali treatment and / or an acid treatment to introduce an ionic group, It is used to modify the water-absorbent resin.

In the alkali treatment and / or the acid treatment,
An ionic group such as an amide group, a carboxyl group, or a substituent of a salt thereof is introduced into acrylonitrile in the polymer material. On the other hand, an ionic group such as a sulfonic acid group is introduced into the styrene portion, and an ionic group such as a substituent of a hydroxyl group or a salt thereof or a sulfonic acid group is introduced into the conjugated diene portion.

The alkali used for the alkali treatment is preferably an inorganic alkali. As inorganic alkalis,
Alkali metals (sodium, lithium, potassium, etc.)
And alkaline earth metals (magnesium, calcium, etc.)
Oxides, hydroxides, carbonates, bicarbonates, acetates, sulfates, phosphoric acid baits in excess of compounds and aqueous solutions.

By reacting the above-mentioned alkali with the polymer material, the acrylonitrile part and the conjugated diene part undergo hydrolysis, and an amide group and a hydroxyl group are introduced, respectively. Further, by adding an alkali, the amide group becomes a carboxyl group or a salt thereof,
In addition, the hydroxyl group will be replaced by a hydroxyl salt.

The acid used for the acid treatment is preferably an inorganic acid. Examples of the inorganic acid include a sulfonating agent such as concentrated sulfuric acid, sulfuric anhydride, fuming sulfuric acid, and chlorosulfonic acid, and nitric acid, fuming nitric acid, phosphoric acid, phosphorus chloride, and phosphorus oxide. Among them, concentrated sulfuric acid, sulfuric anhydride, fuming sulfuric acid, and chlorosulfonic acid are preferred, and concentrated sulfuric acid of 70% by weight or more is particularly preferred.

By reacting the above-described inorganic acid with the polymer material, the acrylonitrile portion undergoes hydrolysis,
An amide group or a carboxyl group is introduced. On the other hand, a sulfonic acid group or -PO (O (O)
_{H) 2, -CH 2 PO (} OH) 2, so that the ionic group such as a nitro group is introduced.

When a sulfonating agent is used in the above-mentioned acid treatment, a Lewis base may be used in combination. Examples of the Lewis base include alkyl phosphate (triethyl phosphate, trimethyl phosphate), dioxane, acetic anhydride, ethyl acetate, ethyl palmitate, diethyl ether, thioxane, and the like. In this acid treatment, the amount of the Lewis base used in combination is
1 to 20 with respect to the whole monomer unit in the polymer material
0 mol%, preferably 2 to 100 mol%. In this acid treatment, if the amount of the Lewis base added is less than the above-mentioned range, a gel is easily generated during the reaction, which is not preferable. On the other hand, when the amount of the Lewis base added is larger than the above range, the sulfonation reaction hardly proceeds, which is not preferable.

The amount of the alkali and / or acid to be charged is largely affected by the concentration of the alkali or acid, but is generally 1 to 500 times, preferably 5 to 200 times the weight of the polymer material. is there.

If the charge of the alkali and / or acid is too small, the rate of introduction of ionic groups into styrene or conjugated diene and the rate of hydrolysis of acrylonitrile decrease.
The performance (water absorption) as a water absorbent resin is reduced.
On the other hand, if the charged amount of alkali and / or acid is too large, it is necessary to wash and neutralize excess alkali and acid, which is disadvantageous in terms of economy and work.

These alkalis and acids may be used alone or in combination of two or more. When used in combination, they may be mixed (however, the alkali and the acid are not mixed and used) or may be added sequentially. For example,
After the acid treatment, an alkali treatment may be carried out, or after the alkali treatment, an acid treatment may be carried out, or after treatment with concentrated sulfuric acid, treatment with sulfuric anhydride (acid treatment → acid treatment) May be.

Here, specifically, the alkali treatment and / or the acid treatment are performed as follows.

(1) First, it is preferable to add either concentrated sulfuric acid or chlorosulfonic acid to the polymer material, and then to add either sulfuric anhydride or fuming sulfuric acid. In this method, a sulfonic acid group is first introduced into styrene or a conjugated diene portion of a polymer material by adding either concentrated sulfuric acid or chlorosulfonic acid. Then, by adding either sulfuric anhydride or fuming sulfuric acid, the polymer material is subjected to sulfone crosslinking. Therefore, according to this method, a water-absorbing resin having a high degree of crosslinking can be obtained. Therefore, according to this method, a functional resin having excellent shape stability in an aqueous system can be obtained.

(2) First, a sulfonating agent (sulfuric anhydride, fuming sulfuric acid, chlorosulfonic acid, concentrated sulfuric acid, etc.) is reacted with a polymer material in a solvent to introduce a sulfonic acid group into the polymer material. can do. Alternatively, a carboxyl group can be introduced into a polymer material by adding n-butyllithium to a solvent and further reacting with dry ice. Alternatively, phosphorus trichloride is added to a solvent and the resultant is further hydrolyzed to introduce a —PO (OH) ₂ group into the polymer material.

(3) Waste polystyrene resin is chloromethylated with chloromethyl ether and a Lewis acid, and further reacted with ammonia or various amine compounds to convert the resin into a tertiary or quaternary amine salt. Can be introduced. Alternatively, the —PO (OH) ₂ group can be introduced into the waste polystyrene resin by reacting the waste polystyrene resin with a chloromethylated product and phosphorus trichloride and further hydrolyzing it.

Further, the above-mentioned modification treatment may be performed in an alkali or an acid, or may be performed in a system using an organic solvent.

As a solvent used in the reaction system, an aliphatic halogenated hydrocarbon having 1 to 2 carbon atoms (preferably 1, 2
-Dichloroethane, chloroform, dichloromethane,
1,1-dichloroethane), aliphatic cyclic hydrocarbon (preferably, cyclohexane, methylcyclohexane, cyclopentane), nitromethane, nitrobenzene, sulfur dioxide, paraffin hydrocarbon having 1 to 7 carbon atoms, acetonitrile, carbon disulfide, tetrahydrofuran , Tetrahydropyran, 1,2-dimethoxyethane, acetone, methyl ethyl ketone, thiophene and the like. Preferred are aliphatic halogenated hydrocarbons having 1 to 2 carbon atoms, aliphatic cyclic hydrocarbons, nitromethane, nitrobenzene, and sulfur dioxide. These solvents may be used alone or as a mixture of two or more. The mixing ratio in the above-mentioned solvent is not particularly limited.

The amount of the organic solvent to be added is preferably less than about 200 times the weight of the polymer material. When the amount of the organic solvent added is larger than this range, the reaction rate of the reforming treatment becomes low and it is economically disadvantageous.

The alkali, acid and organic solvent once used in the above-mentioned reforming treatment may be recovered and used as it is after completion of the reaction, or may be recovered by a technique such as extraction or distillation and used again in the reaction.

In the above-described alkali treatment and / or acid treatment, it is preferable to reduce the particle size of the polymer material as a raw material. By increasing the surface area of the polymer material, the portion to be modified is increased, and the introduction rate of ionic groups into the polymer material can be improved.

In order to reduce the particle size of the polymer material as described above, a method of pulverizing a lump of the polymer material with a pulverizer or the like and sorting the pulverized material may be used.
When a waste material is used as a polymer material, a rubber component may be contained in the polymer material. Therefore, it is preferable to perform a pulverization process after freezing the waste material at a low temperature.

In order to reduce the particle size of a polymer material such as a polystyrene resin, a method of melting the polymer material by heating and making the polymer material heated and melted into fine particles may be used. It can also be used.

Specifically, in the present invention, in order to improve the introduction rate of ionic groups, it is preferable that the small size of the polymer material is set to a size that passes through a mesh of 3.5 mesh or more. If the particle size of the polymer material is larger than this, the surface area of the reactant becomes small and it is difficult to perform the modification treatment, so it takes a long reaction time and is practical, and the performance (water absorption) as a water-absorbing resin is greatly increased Will decrease.

In the above-described reaction for introducing an ionic group into a polymer material, a dispersant may be added to the reaction system when introducing the ionic group. As a result, the polymer material is well dispersed in the reaction system, and the introduction rate of the ionic group is improved.

Further, the reaction temperature of the above-mentioned reforming treatment is as follows:
It varies greatly depending on the type of alkali or acid, and whether or not an organic solvent is used, but it is 0 to 200 ° C, preferably 30 to 15 ° C.
0 ° C. If the temperature is too low, the reaction rate becomes too slow to be practical, and the introduction rate of ionic groups is reduced, so that a good water absorbing effect cannot be obtained. On the other hand, when the temperature is too high, the molecular chain of the polymer material is easily broken by thermal decomposition, and the resin shows water solubility, and cannot be used as a water-absorbing resin.

The reaction time varies greatly depending on the reaction temperature, but is generally about 1 minute to 80 hours.
5 minutes to 20 hours. If the reaction time is too short, the reaction does not proceed sufficiently. On the other hand, if the reaction time is too long, the production efficiency will deteriorate.

As described above, the reaction product into which the ionic group has been introduced by the alkali treatment or the acid treatment may be washed with a large amount of water or neutralized with a reverse aqueous solution. Alternatively, the reaction product from the reaction system may be first filtered through a filter or the like, and the reaction product may be poured into a large amount of water or a reverse aqueous solution for washing. In the washed reactant, part of the acrylonitrile group is hydrolyzed to form acrylamide, and the hydrophilicity is further improved.

Since the modified product obtained as described above is in a gel state, it is subjected to drying treatment such as sunlight, heating, decompression, centrifugation, and pressing to obtain a desired water-absorbing resin.

In the present invention, a water-absorbing resin can be obtained from a polymer material containing an inorganic pigment and / or a metal powder pigment and acrylonitrile by the above-described treatment method. This water-absorbing resin has a large water-absorbing surface, and has an amide group and a hydroxyl group that are excellent in water absorption and an ionic group of a strong acid such as a sulfonic acid group. It shows a high water absorption effect not only for water but also for an aqueous electrolyte solution.

The water-absorbing resin thus obtained is used for sanitary materials such as disposable diapers and sanitary articles, and for construction, agriculture, forestry, and horticultural materials for imparting water retention to soil (for greening deserts and the like). , Fragrance for long lasting fragrance, dehydrating agent from organic and inorganic substances, digestive agent, sealing agent, packing agent, anti-condensation agent, antistatic agent, coating agent,
It can be used for various uses such as a desiccant and water treatment.

[0087]

The present invention will be described below in more detail with reference to examples. It goes without saying that the present invention is not limited to this embodiment.

Example 1 ABS resin of a chemical product (constituting units: styrene unit: 52 mol%, acrylonitrile unit: 29
Mol%, butadiene unit contained 19 mol%. Contains 1% by weight of carbon black as an inorganic pigment. ) Was freeze-pulverized to obtain a pulverized product of 16 to 65 mesh. And
3 g of this pulverized product was added to 90 g of 89% by weight concentrated sulfuric acid, and reacted at 80 ° C. for 20 minutes. After the completion of the reaction, the solid matter in the reaction system is filtered with a glass filter, washed with water,
It dried at 115 degreeC with the circulating air dryer for 2 hours. Thereby, a black water-absorbing resin (Example 1) was obtained.

The sulfonic acid groups in this water-absorbent resin (Example 1) accounted for 42 mol% of all monomer units.

Example 2 Guard panel (transparent part) of used 8 mm cassette tape (SAN resin waste material; 64 mol% of styrene unit and 3 units of acrylonitrile unit as constituent units)
Contains 6 mol%. Contains no inorganic pigments. ) And crush
A crushed product of 6 to 65 mesh was used. Then, 2% by weight of titanium oxide powder was added to the pulverized product, and kneaded with a small extruder (250 ° C.).

Next, 3 g of the pulverized product was added to 90 g of 96% by weight concentrated sulfuric acid and reacted at 60 ° C. for 60 minutes. Thereafter, it is cooled to room temperature, and 60% by weight of fuming sulfuric acid:
An additional 0.5 g was added, and the mixture was further reacted for 30 minutes. After the completion of the reaction, the solid matter in the reaction system was filtered with a glass filter, washed with water, and then dried with a dryer for 2 hours. Thereby, a pale yellow water-absorbing resin (Example 2) was obtained.

The sulfonic acid groups in this water-absorbent resin (Example 2) accounted for 51 mol% of all monomer units.

Example 3 Used personal computer housing (ABS resin waste material; constituent units include 45 mol% of a styrene unit, 36 mol% of an acrylonitrile unit, and 19 mol% of a butadiene unit. Carbon black as an inorganic pigment Was contained in 1% by weight.), And the same treatment as in Example 1 was performed. Thereby, a black water-absorbing resin (Example 3) was obtained.

The sulfonic acid groups in this water-absorbent resin (Example 3) accounted for 38 mol% of all monomer units.

Example 4 The same pulverized ABS resin as the raw material used in Example 1 was added to a 7% by weight aqueous sodium hydroxide solution and reacted at 98 ° C. for 2 hours. After completion of the reaction, the solid matter in the reaction system is filtered,
After washing with water, it was dried in a dryer for 2 hours. This allows
A black water-absorbing resin (Example 4) was obtained.

The sodium carboxylate group in this water absorbent resin (Example 4) was 34 mol% of the total monomer units.

Comparative Example 1 An ABS resin (natural type) having the same resin composition as in Example 1 and containing no pigment (carbon black) was freeze-pulverized to obtain a pulverized product having a mesh size of 16 to 65 mesh. This pulverized material is treated in the same manner as in Example 1,
A pale orange water absorbent resin (Comparative Example 1) was obtained.

The sulfonic acid groups in this water absorbing resin (Comparative Example 1) accounted for 27 mol% of all monomer units.

Comparative Example 2 A transparent water-absorbent resin (Comparative Example 2) was obtained in the same manner as in Example 2 except that titanium oxide was not added.

The sulfonic acid groups in this water-absorbent resin (Comparative Example 2) accounted for 33 mol% of all monomer units.

Comparative Example 3 An ABS resin (natural type) having the same resin composition as in Example 1 and containing no pigment (carbon black) was freeze-pulverized to obtain a pulverized product of 16 to 65 mesh. This pulverized material is treated in the same manner as in Example 4,
A yellow water absorbent resin (Comparative Example 3) was obtained.

The sodium carboxylate group in this water-absorbent resin (Comparative Example 3) was 22 mol% of the total monomer units.

Characteristic Evaluation 1 The water absorbency of each of the water absorbent resins of Examples 1 to 4 and Comparative Examples 1 to 3 was examined as described below.

1 g of the water-absorbing resin of each of the examples and comparative examples was immersed in pure water, and the weight was measured after 30 seconds, 2 minutes, and 5 minutes. Table 1 shows the results.

[0105]

[Table 1]

From the results in Table 1, it can be seen that the water-absorbing resin containing an inorganic pigment (Examples 1 to 4) has a higher water absorption than the water-absorbing resin containing no inorganic pigment (Comparative Examples 1 to 3). It can be seen that both the speed and the water absorption are excellent.

Further, by applying the production method of the present invention, the water absorbing resin using the ABS resin waste material having substantially the same composition and pigment as in Example 1 (Example 4) has excellent water absorption rate and water absorption. It can be seen that the magnification is shown.

Characteristic Evaluation 2 The water absorbency of each of the water absorbent resins of Examples 1 to 4 and Comparative Examples 1 to 3 was examined as described below.

1 g of the water-absorbent resin of each of the examples and comparative examples was immersed in artificial urine and 1% by weight of calcium chloride, and the weight after 5 minutes was measured. Table 2 shows the results.

[0110]

[Table 2]

From the results shown in Table 2, the water-absorbent resin containing an inorganic pigment (Examples 1 to 4) was more artificial than the water-absorbent resin containing no inorganic pigment (Comparative Examples 1 to 3). It can be seen that it exhibits excellent water absorption even in urine and an aqueous electrolyte solution (a bivalent metal salt aqueous solution).

Further, as in the case of the property evaluation 1, it can be seen that by applying the production method of the present invention, the water absorbent resin using the ABS resin waste material (Example 4) also shows excellent water absorbency.

[0113]

As is clear from the above description, according to the present invention, a water-absorbing resin having excellent water-absorbing properties can be obtained.

Further, according to the present invention, waste materials used as polymer materials can be used, which leads to effective use of resources and contributes to environmental conservation of the earth.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08J 3/20 CEZ C08J 3/20 CEZC

Claims (26)

[Claims] 1. A water-absorbing resin comprising an ionic group introduced into a polymer material containing an inorganic pigment and / or metal powder and acrylonitrile. 2. The water-absorbent resin according to claim 1, wherein the polymer material contains acrylonitrile in an amount of 5 to 80 mol%. 3. The water-absorbent resin according to claim 1, wherein the polymer material contains at least one of styrene and conjugated diene. 4. The water-absorbent resin according to claim 1, wherein said polymer material contains at least one of styrene and conjugated diene in an amount of 20 to 95 mol%. 5. The polymer material is acrylonitrile-
The water-absorbent resin according to claim 1, wherein the water-absorbent resin is at least one of butadiene-styrene resin, styrene-acrylonitrile resin, and acrylonitrile-butadiene rubber. 6. The water-absorbent resin according to claim 1, wherein the polymer material contains 0.01 to 20% by weight of an inorganic pigment and / or a metal powder pigment. 7. The inorganic pigment and / or metal powder pigment,
Carbon black, iron black, titanium oxide, zinc white, red iron, ultramarine, navy blue, cobalt blue, lithopone, zinc sulfide, antimony oxide, yellow iron oxide, amber, sienna, ocher, viridian, aluminum powder, brass powder,
The water-absorbent resin according to claim 1, wherein the resin is at least one kind of bronze powder. 8. The water-absorbent resin according to claim 1, wherein the polymer material is a waste material composed of a used resin molded for a specific use. 9. The ionic group is 5 to the polymer material.
2. The composition according to claim 1, wherein the amount is about 95 mol%.
The water-absorbing resin as described in the above. 10. The ionic group includes a sulfonic acid group, a carboxyl group, a —PO (OH) ₂ group, and —CH ₂ PO (OH).
₂ group, -NO ₂ group, according to claim 1, wherein the water-absorbent resin, characterized in that at least one chloromethylated amine group. 11. A polymer material containing an inorganic pigment and / or a metal powder pigment and acrylonitrile is alkali and / or
Alternatively, a method for producing a water-absorbent resin, which comprises performing an acid treatment to introduce an ionic group. 12. The method for producing a water-absorbent resin according to claim 11, wherein the acid treatment is at least one or more inorganic acids. 13. The method according to claim 12, wherein the inorganic acid is at least one of concentrated sulfuric acid, sulfuric anhydride, fuming sulfuric acid, chlorosulfonic acid, nitric acid, fuming nitric acid, phosphoric acid, phosphorus chloride, and phosphorus oxide. A method for producing a water-absorbing resin. 14. The method for producing a water-absorbent resin according to claim 11, wherein the polymer material is dispersed in a sulfonating agent to introduce a sulfonic acid group. 15. In the acid treatment, first, one of concentrated sulfuric acid and chlorosulfonic acid is added.
The method for producing a water-absorbent resin according to claim 11, wherein one of sulfuric anhydride and fuming sulfuric acid is added. 16. The polymer material is dispersed in a solvent,
The method for producing a water-absorbent resin according to claim 11, wherein ionic groups are introduced. 17. The method for producing a water-absorbent resin according to claim 12, wherein a polymer material having a mesh size of 3.5 mesh or more is used in the alkali and / or acid treatment. 18. The polymer material according to claim 11, wherein the polymer material contains acrylonitrile in an amount of 5 to 80 mol%.
A method for producing the water-absorbent resin according to the above. 19. The method according to claim 11, wherein the polymer material contains at least one of styrene and conjugated diene. 20. The method according to claim 11, wherein the polymer material contains at least one of styrene and conjugated diene in an amount of 20 to 95 mol%. 21. The method according to claim 11, wherein the polymer material is at least one of acrylonitrile-butadiene-styrene resin, styrene-acrylonitrile resin, and acrylonitrile-butadiene rubber. 22. The method for producing a water-absorbent resin according to claim 11, wherein an inorganic pigment and / or a metal powder pigment is added to the polymer material in an amount of 0.01 to 20% by weight. 23. The inorganic pigment and / or metal powder pigment may be carbon black, iron black, titanium oxide, zinc white, red bengal, ultramarine, cobalt blue, lithopone, zinc sulfide,
Antimony oxide, yellow iron oxide, amber, sienna,
The method for producing a water-absorbent resin according to claim 11, wherein the method is at least one of ocher, viridian, aluminum powder, brass powder, and bronze powder. 24. The method for producing a water-absorbent resin according to claim 11, wherein the polymer material is a waste material composed of a used resin molded for a specific application. 25. The method according to claim 25, wherein the ionic group is
The method for producing a water-absorbent resin according to claim 11, wherein the amount of the water-absorbent resin is about 95 mol%. 26. The ionic group includes a sulfonic acid group, a carboxyl group, a —PO (OH) ₂ group, and —CH ₂ PO (OH).
₂ group, -NO ₂ group, method for producing a water-absorbent resin according to claim 11, wherein the at least one chloromethylated amine group.