JPS61257235A - Water absorbent resin composition, its preparation and water absorbent-water retention agent - Google Patents

Abstract

PURPOSE:To increase the water absorption velocity and the stability for the humidity by imparting water to a mixture of a water insoluble hydrophilic polymer grain which is produced from a hydrophilic and/or water soluble monomer and salt and/or hydroxide of polyvalent metal. CONSTITUTION:A water insoluble and water absorbent resin composition is obtained by preparing a mixture of a water insoluble hydrophilic crosslinked polymer which is produced from a hydrophilic and/or water soluble monomer and salt and/or hydroxide of polyvalent metal and imparting 0.1-50wt% water for this mixture. In the salt or hydroxide of polyvalent metal mixed with the above-mentioned polymer grain, as the polyvalent metal, bivalent metal such as Mg, Ca, Ba, Zn, Fe and trivalent metal such as Al and Fe are used. The mixing of the polymer grain sand salt and/or hydroxide of polyvalent metal is performed by the dry type mixing and as a nauter mixer a ball mill, etc. are used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a water-absorbing resin composition, its production method, and water-absorbing and water-retaining agents.

[Conventional technology]

In recent years, water-absorbing materials with relatively high water-absorbing capacity have begun to appear in sanitary products, disposable diapers, etc., such as cross-linked polyethylene oxide, cross-linked POVAL, and hydrolyzate of starch-polyacrylonitrile graft polymer 1 self-cross-linked polyacrylic acid metal salt. . However, although these materials have water absorption capacity, they are not sufficiently satisfactory for use in sanitary products, disposable diapers, etc., which require a high water absorption rate.

In other words, the higher the water absorption capacity, the stronger the affinity with water, so when these materials come into contact with water, gelation occurs only in the contact area, which prevents the water from permeating uniformly, making it impossible to obtain a rapid water absorption rate. There was a problem (hereinafter referred to as Mamako).

In order to improve this drawback, methods have been used to increase the rate of water absorption by pulverizing these water-absorbing materials to increase their surface area and increasing the contact surface with water.

In this case, the surface area of the water-absorbing material increases, so the water absorption rate becomes somewhat faster (because a film forms on the surface of the particles where water comes into contact with the particles, and water does not penetrate uniformly, it is difficult to improve the water absorption rate). I couldn't connect.

The present inventors proposed in Japanese Patent Application No. 56-140571 to disperse a hydrophilic cross-linked polymer in a dispersion medium and then further cross-link the surface of the hydrophilic cross-linked polymer with a cross-linking agent. This method is effective for increasing the water absorption rate because when the water-absorbing material comes into contact with water, it promotes uniform penetration of water without gelling only at the contact area, but this method also increases the water absorption rate. The improvements were not yet fully satisfactory and were uneconomical.

On the other hand, Japanese Patent Application No. 59-181682 proposes mixing a water-insoluble water-absorbing resin with inorganic particles, but although this method has some effect on improving the water absorption rate, it is not very satisfactory. Ta.

[Problem that the invention seeks to solve]

In order to improve the water absorption rate of water-absorbing materials, the present inventors have conducted intensive research with the aim of solving the problem that cannot be sufficiently solved by conventional techniques, that is, bulge.

As a result of stacking, a small amount of polyvalent metal salt and/or
Alternatively, it has been discovered that by mixing hydroxide and adding a small amount of water, the liquid to be absorbed can easily pass between each polymer particle without adhesion between the polymer particles. Furthermore, it was discovered that the effect is even better when the water added is an aqueous solution of a polyvalent metal salt, leading to the present invention.

[Means to solve the problem]

The present invention provides modified water obtained by adding water to a mixture of water-insoluble and hydrophilic polymer particles made from hydrophilic and/or water-soluble monomers and polyvalent metal salts and/or hydroxides. Insoluble water-absorbing resin composition (first invention) 0 for mixtures of water-insoluble, hydrophilic polymer particles from hydrophilic and/or water-soluble monomers and polyvalent metal salts and/or hydroxides A method for producing a modified water-insoluble water-absorbing resin composition (second invention), characterized by applying .05 to 50% by weight of water to the surface of the particles, and a hydrophilic and/or water-soluble monomer A water-absorbing and water-retaining agent comprising a water-insoluble water-absorbing resin composition obtained by applying urine to a mixture of water-insoluble, hydrophilic polymer particles and polyvalent metal salts and/or hydroxides. (Third invention).

In the present invention, the polyvalent metal salt or hydroxide mixed with the polymer particles is Kg, Ca/Ba as the polyvalent metal.
*Divalent metals such as Zn + Fe and Al, F
trivalent metals such as e; inorganic normal and double salts of these metals such as halides, nitrates, phosphates, monosulfates, carbonates, or lower organic salts such as oxalates and acetates; It is a hydroxide; specific compounds include calcium chloride, magnesium chloride, ferrous chloride, aluminum chloride, polyaluminum chloride, ferric chloride, iron nitrate,
Calcium nitrate, aluminum nitrate, magnesium phosphate, calcium phosphate, aluminum phosphate, magnesium sulfate, ferrous sulfate, aluminum sulfate, potassium aluminum sulfate, ammonium aluminum sulfate, calcium carbonate, magnesium carbonate, calcium magnesium carbonate, magnesium oxalate, Examples include calcium oxalate, magnesium acetate, calcium acetate, aluminum acetate, calcium hydroxide, and aluminum hydroxide.

These compounds may be used alone or in combination,
Among these, preferred are compounds that are sparingly soluble in water, and particularly preferred are calcium phosphate, aluminum phosphate/calcium oxalate, and calcium hydroxide/aluminum hydroxide.

The amount of polyvalent metal salt and/or hydroxide mixed with the polymer particles is usually 0.01 to 10% by weight, preferably o
, i~5% by weight. If it is less than 0.01% by weight, no effect will be observed, and if it is greater than 10% by weight, no particular improvement in the effect will be observed and the water absorption capacity will decrease, which is not preferable.

The polymer particles and the polyvalent metal salt and/or hydroxide are mixed by dry mixing, but the dry mixing device is not particularly limited as long as it can mix uniformly, and is usually a V-type mixing device. Examples of water used in the present invention include tap water, industrial water, ground water, ion exchange water, and pure water. Preferably it is tap water.

Furthermore, a better water absorption rate can be obtained by containing a water-soluble polyvalent metal salt that can react with the polymer component to form a three-dimensional structure. This polyvalent metal salt used as a crosslinking agent has polyvalent metals such as Mg, Ca,
Divalent metals such as Ba, Zn, F6 and Al, Fe
trivalent metals such as; salts include inorganic normal salts and double salts such as halides, nitrates, and sulfates, or water-soluble compounds such as acetates and lactates; specific compounds include μsium chloride, magnesium chloride, 1st chloride
Iron, aluminum chloride, polyaluminum chloride, ferric chloride, iron nitrate, p-sium nitrate, aluminum nitrate, magnesium sulfate, ferrous sulfate, aluminum sulfate, potassium aluminum sulfate, ammonium aluminum sulfate, magnesium acetate, calcium acetate, Examples include aluminum acetate and calcium lactate.

Among these, preferred are calcium salts and aluminum salts, and particularly preferred are sulfates and acetates.

Water-insoluble, hydrophilic polymers from hydrophilic and/or water-soluble monomers used in the present invention include (R water-soluble and/or water-soluble monomers) and/or (hydrophilic and/or or water-soluble monomer) (A)
and polysaccharide (B), such as starch-acrylonitrile, /1/graft copolymer hydrolyzate, cellulose-acrylic acid graft copolymer and salts thereof;
Polymer of (A) and crosslinking agent (C), such as polyacrylamide crosslinked with a divinyl compound (methylenebisacrylamide, etc.) and its partial hydrolyzate, crosslinked poval, JP-A-52-14689, JP-A-52 -274
Saponified crosslinked vinyl ester-unsaturated carboxylic acid copolymer described in No. 55, crosslinked polyethylene oxide, etc.; (A), (B), and (C) are polymerized as essential components and hydrolyzed if necessary. For example, Japanese Patent Publication No. 6B-46199, Japanese Patent Publication No. 5B-46
Examples thereof include crosslinked starch-acrylamide graft copolymers, crosslinked starch-acrylic acid graft copolymers and salts thereof described in No. 200 and Japanese Patent Publication No. 55-4462. Two or more of these hydrophilic crosslinked polymers may be used in combination.

The particle size of the polymer particles is usually 5 to 5000 microns or less, preferably 20 to 500 microns.

Polymer particles are usually 60m1! Water absorption capacity of /g or more It is something that

The amount of water based on the mixture of polymer particles and polyvalent metal salt and/or hydroxide is usually 0.05 to 150% by weight, preferably 0.5 to 10%. The amount of water is 0.0
If it is less than 5%, the surface modification of the polymer particles is insufficient;
If it exceeds 50 inches, heat treatment becomes necessary and the density of the surface layer of the polymer particles becomes too high, which actually reduces the absorption rate.

The amount of the water-soluble polyvalent metal salt used as a crosslinking agent is usually 0 to 10% by weight, preferably 0.1 to 5% by weight, and less than 10% by weight, based on the hydrophilic crosslinked polymer. If it is too large, the water absorption rate can be improved, but the water absorption capacity will drop significantly, making it difficult to use it practically as a water absorbent resin.

As a method for applying water or water containing a polyvalent metal salt soluble in water (represented by water unless otherwise specified) to a mixture of polymer particles and a polyvalent metal salt and/or hydroxide, ( 1) Method of contact treatment by spraying water onto a mixture of water-insoluble, hydrophilic polymer particles and polyvalent metal salts and/or hydroxides, (++) Method of contact treatment of water vapor with water-insoluble, hydrophilic polymer particles and polyvalent metal A method of contact treatment in which water vapor is converted into water droplets on the surface of polymer particles by contacting with a mixture of metal salts and/or hydroxides is mentioned.

The temperature in the contact treatment is room temperature (although heating is not particularly necessary, heating may be performed for 1 to 120 minutes, preferably 2 to 80 minutes).

The improved water absorbent resin composition of the present invention contains fillers, pigments, ultraviolet absorbers, antioxidants, fungicides, fungicides, herbicides, fertilizers, fragrances, deodorants, reducing agents, etc. It may also be used. In particular, when a reducing agent is included in the resin composition of the present invention, the metal salt used also in the present invention is
It becomes a salt, and this secondary salt has the added feature of exhibiting deodorizing ability. Examples of reducing agents include thiourea and L-ascorbic acid.

The water-insoluble water-absorbing resin composition of the present invention can be used as a water-absorbing and water-retaining agent. The water absorbing and water retaining agents include the following.

(1) Water absorption and water retention agents for water absorbent articles, disposable diapers, sanitary napkins, wound dressings, incontinence bats, water absorption improvers for various paper and textile products, sweat absorbency imparting agents, etc., for example, patent application No. 149090/1983 1977
- Those described in No. 82566, etc.

(11) Water retention materials for agriculture, forestry and horticulture Soil water retention improvers, efficacy sustaining agents for agricultural chemicals and fertilizers, sphagnum moss substitutes, water retention agents for plant transplants, water retention agents for pots for growing plants, etc. For example, Japanese Patent Publication No. 55-4462, Japanese Patent Publication No. 52-827
No. 15, JP 56-45882, JP 58-81
What is described in No. 919, etc.

in) Water-absorbing materials for construction Anti-condensation agents for interior building materials such as wall materials and ceiling materials, such as those described in JP-A-58-65075.

(1v) Other dehydrating agents for civil engineering and various industries (methanol 1 ethanol,
dehydrating agents for liquids such as benzene, petroleum ether, gasoline, vegetable oil, heavy oil, etc.), heavy metal adsorbents, sludge coagulants,
Control and release agents for various drugs, fragrances, etc., such as Japanese Patent Publication No. 58-1624 and Japanese Patent Application Laid-open No. 58-107.
What is described in 480 etc.

〔Example〕

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto.

Examples 1 to 4 Water-insoluble, hydrophilic polymer particles (Sanyo Chemical Co., Ltd. Sanwet) IM-1000U; Contains about 15 microparticles of 50μ or less > 100 parts and 1 part of Ihyaluminum hydroxide
The mixture was mixed in a V-type mixer for 10 minutes. This mixture 40
into the chamber (1, 81) of a device (for example, spray dryer OA-21' manufactured by Yamato Scientific Co., Ltd.) equipped with an air inlet and an air outlet, and a water spray nozzle. , 1% water to the mixture while blowing air at a flow rate of 0-2 m”/min, respectively.
s 1%*5ch, 10% water absorbent resin compositions (A), (B), (C).

CD).

Examples 5-8 In Examples 1-4, 10 aluminum sulfate in water
water-absorbent resin compositions (E), (F), CG), and (H) were obtained by dissolving the water-absorbing resin compositions (E), (F), CG), and (H).

Example 9 The water-absorbing resin compositions obtained in Examples 1 to 8 had 0.
The absorption amount and absorption rate of 94 saline solution were measured.

The results are shown in Table-1. The absorption amount is measured using 20
0 mesh nylon nonwoven fabric is made into a bag shape, and resin composition 1! ! was encapsulated, immersed in 0.9% saline for 80 minutes, taken out, drained for 15 minutes, and then measured for increased weight. Regarding the absorption rate, a 200-mesh nylon nonwoven fabric was placed on a support plate with small holes. Place the o, i, and p resin compositions on top of this, contact with the liquid from the bottom, and measure the amount that the resin composition absorbs 0.9 i saline in 2 minutes, and calculate the amount absorbed per 1 g of the resin composition. It was converted into

Comparative examples 1 to 8 Comparative Example 1 Sanwet) IM-1000U untreated product.

Comparative Example 2 In Example 1, Sanwet) IM-10
Absorbent resin composition 11''J) was obtained by mixing aluminum hydroxide with 00U.

Comparative Example 3 In Example 8, Sanwet) IM-10
An absorbent resin composition (K) was obtained by spraying only water to 00U without mixing aluminum hydroxide.

Table 1 [Effects of the invention] Water absorbent resin composition of the present invention and water absorbent containing the same,
The water-retaining agent is a water-absorbing resin composition that promotes uniform permeability of water and has a significantly high water absorption rate.

In addition to the above-mentioned improvement in water absorption rate, the product of the present invention is characterized by its stability against humidity, that is, even when the water-absorbing resin composition of the present invention is left under high humidity, resin particles do not block each other. It is also excellent in terms of being difficult to peel, and stability over time, that is, maintaining water retention and shape retention during long-term use.

Furthermore, it has the advantage of generating less dust when handling powder.

Procedural amendment dated June 1, 1985 Manabu Shiga, Commissioner of the Patent Office, 1985 Patent Application No. 98782 2, Name of the invention: Water-absorbing resin composition, its manufacturing method and water absorption, Water-retaining agent 3, Person making the amendment Column 7 of ``Scope of Claims'' and 7 Detailed Description of the Invention in the Description of the Invention, Contents of Amendment, Attachment 1, Claims from page 1, line 1 to page 4, line 9 of the specification Correct as follows.

-” [Examples 10 to 13 (See next page) Table-2

Claims (1)

[Claims] 1. Water is added to a mixture of water-insoluble and hydrophilic polymer particles made from hydrophilic and/or water-soluble monomers and polyvalent metal salts and/or hydroxides. A modified water-insoluble water-absorbing resin composition characterized by the following. 2. The water-absorbing resin composition according to claim 1, wherein the amount of the polyvalent metal salt and/or hydroxide is 0.01 to 10% by weight based on the polymer component. 3. The water-absorbing resin according to claim 1 or 2, wherein the water contains a water-soluble polyvalent metal salt capable of reacting with the polymer component to form a three-dimensional structure. Composition. 4. Water-insoluble, hydrophilic polymers include hydrolysates of starch-acrylonitrile graft copolymers, cellulose-acrylic acid graft copolymers and salts thereof, polyacrylamide crosslinked with divinyl compounds and partial hydrolysates thereof, crosslinked selected from the group consisting of poval, saponified vinyl ester-unsaturated carboxylic acid copolymer, cross-linked polyethylene oxide, cross-linked starch-acrylamide graft copolymer, cross-linked starch-acrylic acid graft copolymer, and salts thereof. The water-absorbing resin composition according to claim 1, 2 or 3, which is a polymer. 5. Water-insoluble, hydrophilic polymers (hydrophilic and/or water-soluble monomers) and/or (monomers that become hydrophilic and/or water-soluble monomers upon hydrolysis) (A) A polymer with saccharide (B); a polymer with (A) and a crosslinking agent (C); or by polymerizing (A), (B), and (C) as essential components and performing hydrolysis if necessary. The water-absorbing resin composition according to any one of claims 1 to 4, which is the obtained polymer. 6. 0.1 to 50% by weight of water based on the mixture of water-insoluble, hydrophilic crosslinked polymer particles from hydrophilic and/or water-soluble monomers and polyvalent metal salts and/or hydroxides; 1. A method for producing a modified water-insoluble water-absorbent resin composition, characterized by imparting the following properties. 7. The manufacturing method according to claim 6, wherein the polymer particles are particles of a super absorbent resin having a water absorption capacity of 60 ml/g or more. 8. The production method according to claim 6 or 7, wherein the amount of the polyvalent metal salt and/or hydroxide is 0.01 to 10% by weight based on the polymer component. 9. Claim 6, 7 or 8, wherein the water contains a water-soluble polyvalent metal salt capable of reacting with the polymer component to form a three-dimensional structure. manufacturing method. 10. Water-insoluble water-absorbent resin composition obtained by adding water to a mixture of water-insoluble and hydrophilic polymer particles made from hydrophilic and/or water-soluble monomers and polyvalent metal salts and/or hydroxides. A water-absorbing and water-retaining agent containing substances. 11. The water absorbing/water retaining agent according to claim 10, wherein the water absorbing/water retaining agent is a water absorbing/water retaining agent for absorbent articles. 12. Absorbent articles are disposable diapers, sanitary napkins,
Claim 1, which is a water absorption improver or sweat absorption agent for wound dressings, incontinence pads, various papers and textile products
The water absorbing and water retaining agent described in item 1. 13. Claims in which the water absorbing and water retaining agent is a water retaining agent for agriculture, forestry and horticulture, a water absorbing material for construction, a dehydrating agent for civil engineering and various industries, a heavy metal adsorbent, a sludge coagulant, a drug, and a fragrance control/release agent. Water absorbing and water retaining agent according to item 10.