JPH02242975A - Production of water-absorptive composite, continuous production thereof and production apparatus therefor - Google Patents

Abstract

PURPOSE:To efficiently obtain the subject composite causing no slipping out by impregnating a base material with a solution containing both a water-soluble ethylenic unsaturated monomer convertible into water absorptive polymer and a radical polymerization initiator, sandwiching the resultant base material with polymerization-inert surfaces and then by carrying out polymerization. CONSTITUTION:A base material 10 (e.g. polypropylene nonwoven fabric) is immersed in an aqueous solution 4 containing (A) a water-soluble ethylenic unsaturated monomer [pref. (meth)acrylic acid or its salt] convertible into water-absorptive polymer through polymerization and (B) a water-soluble radical polymerization initiator (e.g. persulfate). Thence, the resultant base material is put to thermal polymerization in a sandwiched state between a pair of endless belts 1A and 1B consisting of glass fiber or metal such as steel with polymerization-inert surfaces facing each other followed by introduction into a hot air drying machine 6 where a drying is made, and the resulting product is rolled on a roll 8, thus readily obtaining the objective water absorptive composite in high efficiency using simple apparatuses.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a water-absorbing composite in which a water-absorbing polymer is firmly fixed to a base material. More specifically, it is a highly safe water-absorbing composite with excellent water-absorbing ability and significantly less residual monomer in the water-absorbing polymer, in which the water-absorbing polymer does not fall off from the base material even after absorbing a large amount of water. The present invention relates to a method for easily and efficiently manufacturing , a method for continuously manufacturing with high productivity, and an apparatus used to carry out the method.

[Conventional technology]

In recent years, various methods have been proposed in which a water-soluble monomer that can be converted into a water-absorbing polymer is applied to a substrate and then polymerized as a method for obtaining a water-absorbing composite by fixing a water-absorbing polymer to a substrate ( JP-A-60-149609, JP-A-62-243606, JP-A-60-15138
1, Japanese Patent Application Laid-Open No. 62-243612), the polymerization reaction of the water-soluble monomer is inhibited by oxygen in the air, so it is necessary to use an inert atmosphere for polymerization, such as in an oscine atmosphere completely replaced with nitrogen gas. [Problem to be Solved by the Invention] However, according to these known methods, when polymerizing the monomer applied to the base material, the base material is placed in a polymerization zone set under specific conditions. It is essential to hold the polymer for a long time, the polymerization equipment itself becomes large, and there is a lot of energy loss, which is not preferable for the industrial production of water-absorbing composites. Furthermore, the obtained water-absorbing composite had insufficient water-absorbing ability and had a large amount of residual monomer.

This invention solves the above-mentioned problems in industrially manufacturing a water-absorbing composite.

Therefore, an object of the present invention is to firmly fix a water-absorbing polymer to a base material, to exhibit excellent water-absorbing ability without falling off from the base material even after the polymer swells, and to have a water-absorbing polymer that is firmly fixed to a base material. It is an object of the present invention to provide a method for easily and efficiently producing a water-absorbing composite suitable for sanitary materials such as disposable diapers, which has significantly less residual monomer. The next object of this invention is to provide a method by which such a water-absorbing composite can be produced easily, efficiently, and continuously. A further object of the present invention is to provide a manufacturing apparatus for use in implementing a continuous manufacturing method.

[Means to solve the problem]

This invention involves applying an aqueous solution containing a water-soluble ethylenically unsaturated monomer and a water-soluble radical polymerization initiator that can be converted into a water-absorbing polymer by polymerization to a base material, and then facing the base material to which the aqueous solution has been applied. The present invention relates to a method for producing a water-absorbing composite in which the monomers are polymerized while being sandwiched between polymerization-inactive surfaces.

This invention comprises: (1) applying an aqueous solution containing a water-soluble ethylenically unsaturated monomer that can be converted into a water-absorbing polymer by polymerization and a water-soluble radical polymerization initiator to the substrate while moving the substrate; The present invention relates to a method for continuously producing a water-absorbing composite, in which the monomer is continuously passed through polymerization zones in the order in which the monomer is polymerized while the base material is sandwiched between polymerization inert surfaces.

Further, the present invention includes the following means (1) and (2) disposed along the moving route of the base material, and while continuously moving the base material, a water-soluble polymer that can be converted into a water-absorbing polymer by polymerization is provided. An aqueous solution containing an ethylenically unsaturated monomer and a water-soluble radical polymerization initiator is applied to a base material, and the monomer is polymerized while the base material is sandwiched between opposing polymerization-inactive surfaces. This is a water-absorbing composite production device that fixes water-absorbing polymers on the water-absorbing composite.

(2) A means for depositing on the moving substrate an aqueous solution containing a water-soluble ethylenically unsaturated monomer and a water-soluble radical polymerization initiator that can be converted into a water-absorbing polymer by polymerization.

(2) having means for setting opposing polymerization-inactive surfaces and a gap corresponding to the thickness of the base material between the polymerization-inactive surfaces, such that the base material to which the aqueous solution is attached is Polymerizing the monomer while passing through the gap,
Polymerization means for fixing water-absorbing polymers to substrates.

The base material used in this invention is not particularly limited as long as it is desired to impart water absorbency, and can be appropriately selected from various materials depending on the intended use of the resulting water absorbent composite. For example, sponge-like porous substrates such as sponge and synthetic resin foam, synthetic fibers such as polyester and polyolefin, paper made of cellulose fibers such as cotton and bulbs, fiber substrates such as string, nonwoven fabrics, and woven fabrics are used. . The long base material used in the continuous production method is not particularly limited as long as it has a length sufficient to allow continuous passage through the polymerization zone and drying zone described below. Various materials depending on the application (e.g. those mentioned above)
It can be selected and used as appropriate. Alternatively, in the continuous manufacturing method, not only long base materials but also short base materials of various lengths can be used. For example, if the base material is placed on a base material moving table such as a belt or a tray and moved, it can also be applied to a continuous manufacturing method. In this case, it is convenient during polymerization that the surface of the base material moving table that is in contact with the base material is an inactive surface for polymerization.

The water-soluble ethylenically unsaturated monomer used in this invention is not particularly limited as long as it can be polymerized and converted into a water-absorbing polymer, such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, Carboxyl group-containing unsaturated monomers such as unsaturated carboxylic acids such as maleic acid, fumaric acid, and citraconic acid, and their alkali metal salts such as lithium, sodium, and potassium, ammonium salts, and organic substituted ammonium salts; 2 (meth) Acryloylethanesulfonic acid, 2(meth)acryloylpropanesulfonic acid, (meth)acryloylpropane-2-sulfonic acid, 3(meth)acryloylpropanesulfonic acid, 2-(meth)acryloylbutanesulfonic acid, (meth)acryloylbutane- 2-sulfonic acid, 4
(meth)acryloylbutanesulfonic acid, 2-(meth)
Acrylamido-2-methylpropanesulfonic acid, 2-
(meth)acrylamidoethanesulfonic acid, 3-(meth)acrylamidopropanesulfonic acid, 4-(meth)acrylamidobutanesulfonic acid, vinylsulfonic acid, (
Unsaturated monomers containing sulfonic acid groups such as unsaturated sulfonic acids such as meta)allylsulfonic acid, their alkali metal salts, alkaline earth metal salts such as calcium and magnesium, ammonium salts, and organic substituted ammonium salts; ) Water-soluble unsaturated monomers such as acrylamide, (meth)acrylonitrile, vinyl acetate, N,N-dimethylaminoethyl (meth)acrylate and its quaternized products; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate , polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, methoxypolypropylene glycol mono(meth)acrylate, methoxypolybutylene glycol mono(meth)acrylate, ethoxypolyethylene glycol mono(meth)acrylate meth)acrylate, ethoxypolypropylene glycol mono
(meth)acrylate, ethoxypolybutylene glycol mono (meth)acrylate, methoxypolyethylene glycol/polypropylene glycol mono (meth)
(Meth)acrylic acid esters such as acrylate, phenoxypolyethylene glycol mono (meth)acrylate, benzyloxypolyethylene glycol mono (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, etc. These can be used alone or in combination of two or more. Among them, it is preferably selected from the group consisting of (meth)acrylic acid and its salts, 2-(meth)acryloylethanesulfonic acid and its salts, 2-(meth)acrylamido-2methylpropanesulfonic acid and its salts, and (meth)acrylamide. At least one monomer. More preferably, (meth)acrylic acid and/or its salt is the main component of the water-soluble ethylenically unsaturated monomer. In this case, considering the reactivity of the monomers and the water absorption properties of the obtained water-absorbing composite, (meth)acrylic acid and its salts should be present in an amount of 50 to 100 mol% based on the total amount of water-soluble ethylenically unsaturated monomers. It is preferable that there be.

In addition, there is no particular restriction on the monomer concentration in the aqueous solution, but considering the time and effort required for drying the resulting water-absorbing composite, it is possible to
The concentration is preferably from 0% by weight to saturation, more preferably from 30 to 70% by weight.

Examples of the water-soluble radical polymerization initiator used in this invention include persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate; peroxides such as hydrogen peroxide and t-butyl hydroperoxide; 2. 7-azobis(2-amidinopropane) dihydrochloride, 2. Examples include conventionally known azo compounds such as r-azobis(N,N'dimethyleneisobutyramidine) dihydrochloride. These polymerization initiators may be used alone, but it is also possible to use a mixture of two or more, and furthermore, sulfites, L
- It can also be used as a redox initiator system in combination with reducing agents such as ascorbic acid and ferrous chloride.

In this invention, it is preferable to include a crosslinking agent in addition to the water-soluble ethylenically unsaturated monomer in the aqueous solution applied to the base material. Examples of crosslinking agents include compounds fa) having two or more ethylenically unsaturated groups in one molecule, and/or functional groups such as carboxyl groups and sulfonic acid groups in the water-soluble ethylenically unsaturated monomer. A compound having two or more reactive groups (bl) can be used, and one or more of these can be used. Examples of the compound (al) include, for example, ethylene glycol di(
meth)acrylate, diethylene glycol di(meth)
Acrylate, triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol di(meth)acrylate, N,N'-methylenebis(meth)acrylamide, triallyl isocyanurate , trimethylolpropane diallyl ether, etc. Examples of the compound (b) include ethylene glycol, diethylene glycol triethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, jetanolamine, triethanolamine, polypropylene glycol, polyvinyl alcohol, pentaerythritol, sorbitol, sorbitan, Polyhydric alcohols such as glucose, mannitol, mannitan, sucrose; ethylene glycol diglycidyl ether, glycerin diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether , 1,6-
These include polyepoxy compounds such as hexanegelicol diglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, and glycerin triglycidyl ether; and polyamine compounds such as ethylenediamine and polyethyleneimine. Compounds Ta) and (bl) may each be used singly or in combination of two or more.

When a polyhydric alcohol is used as a crosslinking agent, the ambient temperature (in the continuous production method, the ambient temperature in the drying zone) is maintained in the range of 150 to 250°C after polymerization, and when a polyepoxy compound is used, it is maintained at 50 to 250°C. It is preferable to heat-treat the water-absorbing composite while maintaining the temperature within this range.

Use of a crosslinking agent is preferable in that the water absorption capacity of the resulting water-absorbing composite can be easily controlled. In addition, the crosslinking agent can be used not only in the aqueous solution applied to the substrate, but also by spraying it on the substrate after polymerization (for example, a substrate that is passing through a drying area). It is also possible to secondary crosslink the water-absorbing polymer.

The ratio of the water-soluble radical polymerization initiator to the water-soluble ethylenically unsaturated monomer is not particularly limited, but it is preferably 0.01 to 5 parts (weight ratio) of the initiator to 100 parts of hexamer. If the amount of initiator used is less than 0.01 parts, the polymerization of the monomer may not be completed, and if it is more than 5 parts, the water absorption capacity of the water-absorbing polymer produced by polymerization may be reduced. In addition, when a crosslinking agent is used, the proportion of the crosslinking agent used is not particularly limited, but it is preferably 0.005 to 5 parts (weight ratio) of the crosslinking agent to 100 parts of the monomer; Even if the amount is small, the water absorbing ability of the water absorbing polymer produced by polymerization may be reduced.

Methods for applying the aqueous solution containing the water-soluble ethylenically unsaturated monomer and the water-soluble radical polymerization initiator (hereinafter sometimes abbreviated as monomer aqueous solution) to the substrate include, for example, spraying or spraying using a sprayer. , coating using a known printing method such as brush coating or roller screen, or a method of impregnating a base material with the aqueous solution and then squeezing it out to a predetermined amount as necessary. The application area is thus equipped with means for applying an aqueous solution. There is no particular limit to the amount of the monomer aqueous solution attached to the base material, but - for boat fishing, 7-mer aqueous solution O4 per 1 part by weight of the base material.
The range is 1 to 100 parts by weight, preferably 0.5 to 2 parts by weight.
It is in the range of 0 parts by weight. Further, the form of adhesion of the aqueous monomer solution may be uniform over the entire surface of the substrate, or may be non-uniform such as various patterns such as stripes, grids, and polka dots.

Further, in order to improve the adhesion efficiency when applying the monomer aqueous solution to the substrate and the water absorption capacity of the obtained water absorbent composite, a thickener and other additives can be included in the 7-mer aqueous solution. Examples of such additives include polyacrylic acids (or salts thereof), polyvinylpyrrolidone, hydroxyethyl cellulose, pulp fibers, etc. In the present invention, a polymerized inert material that faces the base material to which the aqueous 7-mer solution has been applied is used. It is essential to carry out the polymerization reaction in a state where the two surfaces are sandwiched. The water-absorbing composite of the present invention is obtained by polymerization or, if necessary thereafter, by drying the polymerized base material. In the case of a continuous production method, specifically, a substrate coated with an aqueous monomer solution is introduced into a polymerization zone equipped with a device having polymerization-inactive surfaces that sandwich the substrates, and the substrate is introduced into a polymerization zone equipped with a device having polymerization-inactive surfaces that sandwich the substrates. After polymerization, the substrate is continuously passed through a drying area equipped with equipment to heat the substrate while still retaining the substrate in the gas. One example is how to do it.

The polymerization-inactive surface may be any surface that does not transmit oxygen, which inhibits the polymerization of the water-soluble monomer, such as ceramics such as glass fiber, metals such as steel, fluororesin, silicone resin, polyester resin, etc. Examples include surfaces of belts, rolls, films, sheets, plates, etc. made of plastic. These surfaces are preferably treated with fluororesin or mirror-finished to prevent adhesion of water-absorbing polymers produced during polymerization.

The distance (clearance) between opposing polymerization-inactive surfaces is set, for example, to correspond to the normal thickness of the substrate used, that is, the thickness measured without pressure.

An adjuster (e.g., a screw) is placed between the support members supporting each opposing polymerization-inert surface, and rotation of the screw advances or retracts one surface relative to the other to create the appropriate spacing. Adjust to. In this case, it is easy to use base materials with different thicknesses.

Alternatively, if a press plate or the like is used, a spacer with a desired thickness (for example, the same thickness as the base material) may be interposed between both surfaces. In order to advance the polymerization to a high polymerization rate and to produce a water-absorbing composite with excellent water-absorbing ability, it is preferable to raise the temperature of the base material during polymerization while sandwiching the base material between opposing polymerization-inactive surfaces. Specifically, contact heating polymerization is performed with the base material sandwiched between opposing belts, etc., which are set at a predetermined temperature using an electric heater, steam, etc.; A method of non-contact heating polymerization of the base material using microwaves, a method of polymerizing the base material by sandwiching the base material between two heated press plates, etc. can be employed.

The temperature of the substrate at the start of polymerization varies depending on the type and amount of the radical polymerization initiator, the type and concentration of the monomer, etc., but it is generally preferable to keep it at or above the decomposition temperature of the radical polymerization initiator. Specifically, in the case of contact heating, it is preferable to maintain the temperature of the surface on which the base material is sandwiched between 50 and 150°C, and between 100 and 150°C.
It is more preferable to maintain the temperature at 120°C. If the temperature is lower than 50°C, it will be difficult to rapidly advance the polymerization to a high polymerization rate, and if the temperature is higher than 150°C, the base material may deteriorate or the polymerization may proceed rapidly, resulting in poor polymerization. This is not preferable because it may be difficult to control, and since heat is generated once polymerization starts, it is preferable to control the polymerization by adjusting the temperature of the surfaces on which the base materials are sandwiched.

Furthermore, in order to smoothly advance the polymerization to a high polymerization rate,
It is preferable to create a polymerization-inactive gas atmosphere such as nitrogen around the opposing polymerization-inactive surfaces.

The time for polymerization is not particularly limited, but it is preferably 1 to 10 minutes in the case of contact heating polymerization, 10 to 60 seconds in the case of non-contact heating polymerization, and in the case of a continuous production method. , it is sufficient to allow the polymer to pass between opposing polymerization-inactive surfaces for this amount of time.

In this invention, polymerization can be controlled directly through the surfaces that sandwich the substrate, and since the substrates are sandwiched between opposing surfaces, the monomer concentration changes due to evaporation of water. Since it is possible to eliminate the effects of oxygen, etc., which inhibit polymerization, it is possible to easily produce a water-absorbing composite with excellent water-absorbing ability and significantly less residual monomer, with high productivity.

In this way, if the monomer attached to the substrate is sandwiched between opposing polymerization-inactive surfaces on which the monomer aqueous solution has been applied, then the hydrogel of the water-absorbing polymer produced by the polymerization will form. A water-absorbing composite firmly fixed to the substrate is obtained. However, depending on the concentration of the 1,000-sumer aqueous solution used, the obtained water-absorbing composite may become sticky and have poor handling properties.
After polymerization, it is preferable to dry the water-absorbing composite if necessary.

Any method can be used as the drying method, and examples thereof include hot air, microwaves, infrared rays, ultraviolet rays, and the like.

Even in continuous production methods, the base material that has passed through the polymerization zone is
If drying is required, it is subsequently led to a drying zone, where the substrate is dried to obtain the desired water-absorbing composite.

The drying zone in the present invention is equipped with a device that heats the substrate while holding it in a gas, and the gas includes, for example, air, an inert gas such as nitrogen, a water vapor-air mixture, and a water vapor-air mixture. Examples include an inert gas mixture, water vapor, etc. Devices for holding the substrate in the gas atmosphere include, for example, rotatable support rolls and support belts, and heating devices include, for example, heaters with fans that generate hot air, or Examples include devices that generate microwaves, infrared rays, and ultraviolet rays.

The heating temperature of the base material in the drying area may be appropriately set in consideration of drying efficiency, but it is preferably 250'C or less so as not to cause deterioration of the water-absorbing polymer. It is preferable to heat to a temperature of 80° C. or higher.

The residence time of the base material in the drying zone is arbitrary, but it is preferable to let the base material stay in the drying zone until the resulting water-absorbing composite loses its tackiness. Further, the water-absorbing composite and another base material can be bonded together by pressing the other base material onto the water-absorbing composite before the adhesiveness disappears and drying the adhesive.

In the case of a continuous production method, the moving speed of the substrate may be appropriately set depending on the time required for polymerization or drying in the polymerization zone or drying zone and the size of those zones, and is not particularly limited. From the viewpoint of industrial productivity, the moving speed of the substrate is preferably 0.1 to 100 m/min, for example.

In addition, in dry regions, polyvalent metal salts,
A compound having two or more functional groups capable of reacting with a functional group such as a carboxyl group or a sulfonic acid group such as polyethylene glycol diglycidyl ether may be partially added to the base material.

Next, the continuous manufacturing method of the present invention will be explained with reference to the drawings. FIG. 1 is a schematic explanatory diagram showing an example of an apparatus for carrying out the continuous manufacturing method of the present invention, FIG. 2 is a schematic explanatory diagram enlarging a part of the apparatus, and FIG. It is a schematic explanatory diagram showing an example.

In the apparatus shown in FIG. 1, the polymerization zone is composed of endless belts IA and IB that sandwich the base material 10, and the base material 10 is heated near the surfaces of the endless belts IA and IB that are in contact with the base material 10. Steam heaters 3A and 3B are provided for this purpose. Further, in the apparatus shown in FIG. 1, the drying area consists of a hot air dryer 6,
The substrate IO is held by support rolls 9 in air in which hot air is circulated.

On the other hand, in the apparatus shown in FIG. It is sandwiched between the circumferential surface of the roll 13 and the endless belt 14 surface. Further, in the apparatus shown in FIG. 3, the drying area consists of a chamber in which the substrate 10 is heated by infrared rays from an infrared lamp 15.

A long base material 10 is unwound from an unwinding roll 7, passes through a polymerization zone and a drying zone, and is continuously wound up onto a winding roll 8. It is rotated in the winding direction.

In the apparatus shown in FIG. 1, the substrate 10 is first immersed in a seven-mer aqueous solution 4, and then the excess seven-mer aqueous solution is squeezed out by a squeezing roll 5.

The base material IO coated with the aqueous monomer solution is sandwiched between the opposing surfaces of the endless belts IA and IB, and Motsumer polymerization is performed thereon. Clearance C between opposing surfaces of endless belts IA and IB
is set, for example, by a clearance adjuster 20 shown in FIG. The clearance adjuster 20 supports the support members 21A and 21 of the belt drive rolls 2A and 2B.
It is attached between B. The support member 21A is provided at both ends of the two belt drive rolls 2A, and the support member 21B is provided at each end of the two belt drive rolls 2A.
The rollers are attached to both ends of two belt-driven rolls 2B. The clearance adjuster 20 is screwed into the support members 21A and 21B with opposite windings. Clearance adjuster 20 on one side (for example,
Turning it clockwise) brings support members 21A and 21B closer together, thereby reducing the clearance C, while turning it the other way (e.g., counterclockwise) brings support members 21A and 21B closer together.
1B move away from each other, thereby increasing the clearance C. The clearance C is adjusted in this way, for example, to a size corresponding to the thickness of the base material 10. The endless belts IA and IB are driven by heald drive rolls 2A and 2B, respectively, in the moving direction of the base material IO, and the circumferential speeds of the endless belts I-IA and IB are synchronized with the circumferential speed of the take-up roll 8. is preferable. Endless belt IA and IB
Steam heaters 3A and 3B are disposed near the surface in contact with the base material 10 to heat the base material 10 in order to promote the polymerization reaction.

The base material that has passed through the polymerization zone is led to a hot air dryer 6. In the dryer 6 in which hot air is circulated, the substrate is dried while being held in the air by support rolls 9.

Once the base material has been dried in the drying area to such an extent that its tackiness disappears, the base material comes out of the dryer 6 and is wound up on a winding roll 8 to become a product of the water-absorbing composite 11.

In the apparatus shown in FIG. 3, in order to apply the seven-mer aqueous solution to the base material, a method is adopted in which the monomer aqueous solution is sprayed onto the base material lO from the spray nozzle 12. The base material 10 first passes through a polymerization zone while being sandwiched between a portion of the circumferential surface of the heated drum roll 13 and the surface of the endless belt 14, where the monomers are polymerized. Next, base material 1
0 passes near the infrared lamp 15 and is heated and dried by the infrared rays emitted from the lamp 15 to become the water-absorbing composite 11.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the scope of the present invention is not limited only to these Examples. In addition, the water absorption performance (water absorption capacity) of the water-absorbing composite described in the examples, the amount of residual upper bulk in the water-absorbing polymer in the water-absorbing composite, and the shedding rate of the water-absorbing polymer were measured by the following test method. .

(2) Water absorption capacity 0.5 g of the finely cut water-absorbent composite was placed in a tea bag-type bag made of non-woven fabric (40 cranes x 150 fins) and immersed in a 0.9% by weight aqueous sodium chloride solution for 30 minutes. Thereafter, the tea bag was pulled up and drained for 5 minutes, and then the weight of the tea bag was measured, and the water absorption capacity was calculated using the following formula.

■ Amount of residual polymer The amount of water-absorbing polymer contained in the water-absorbing composite is 0.5
The water-absorbent composite was weighed and cut into pieces, and then dispersed in 1 liter of pure water with stirring. 2
After a period of time, the dispersion liquid was filtered using Whatman filter paper, and the amount of residual monomer in the filtrate was measured by high performance liquid chroma-graphing (HPL).
C). The amount of residual upper layer in the water-absorbing polymer was determined from the measured value.

■ A sample with a water-absorbing polymer shedding rate of 5 x 5 cse was immersed in excess 0.9% by weight saline for 1 hour, then the swollen sample was pulled out, and the remaining saline was filtered through a 100-mesh wire mesh. It was dried with hot air at 120° C. for 1 hour and weighed to determine the amount of polymer that had fallen off, and the rate of polymer shedding was determined from the following formula.

Note that the sample was dried in advance at 120° C. for 1 hour, and the weight of the water-absorbing composite was determined.

Example 1 - Partially neutralized aqueous acrylic acid solution (monomer concentration 40% by weight) 75 mol % neutralized with sodium hydroxide 10
0 parts by weight, 0.2 parts by weight of 2,2'-azobis(NN'-dimethyleneisobutyramidine) dihydrochloride and N,N'
-Methylenebisacrylamide After dissolving 5 parts by weight of O, OO, dissolved oxygen in the monomer aqueous solution was removed with nitrogen gas.

This monomer aqueous solution was screen printed on a polypropylene non-woven fabric with a thickness of 30 g/m to give a coating amount of the monomer aqueous solution of 250 g/lrr.

The non-woven fabric coated with the seven-layer aqueous solution was heated at 60°C through a spacer having the same thickness as the normal thickness of the non-woven fabric.
The monomer was polymerized by sandwiching it between heated mirror-finish steel press plates for 5 minutes.

After polymerization, the nonwoven fabric was taken out from between the press plates and heated to 120°C.
The mixture was dried for 5 minutes in a hot air dryer to obtain a water absorbent composite (1).

The performance evaluation results of the obtained water absorbent composite (1) are shown in Table 1.

Example 2 The same monomer aqueous solution used in Example 1 was added to 1 tsubo! ! t
Screen printing was performed on a 45 g/rd polyester nonwoven fabric to give a coating weight of the monomer aqueous solution of 250 g/m.

The monomer was polymerized while the nonwoven fabric coated with the aqueous monomer solution was sandwiched for 5 minutes between the surfaces of a pair of opposing endless belts made of glass fibers treated with fluororesin and heated to 60°C. At this time, the distance between the belt surfaces is
Using an adjuster, the spacing was set to be the same as the normal thickness of the nonwoven fabric.

After polymerization, the nonwoven fabric was taken out from between the belt surfaces and heated to 120°C.
The mixture was dried for 5 minutes in a hot air dryer to obtain a water absorbent composite (2).

The performance evaluation results of the obtained water absorbent composite (2) are shown in Table 1.

Example 3 The same monomer aqueous solution used in Example 1 was
g/rd adhesion amount to polypropylene nonwoven fabric is 300
It was sprayed using a spray nozzle so that the amount was 100 g/g.

While sandwiching the non-woven fabric coated with the 7-summer aqueous solution between a pair of opposing endless belts made of glass fiber treated with fluororesin, a frequency of 2450 MHz was generated at an ambient temperature of 25°C.
The monomer was polymerized by irradiating the nonwoven fabric with microwaves at output 4 (10 W) for 30 seconds. At this time, the distance between the belt surfaces was adjusted using an adjuster so that the distance was the same as the normal thickness of the nonwoven fabric. set.

After polymerization, the nonwoven fabric was taken out from between the belt surfaces and heated to 120°C.
The mixture was dried in a hot air dryer for 5 minutes to obtain a water absorbent composite (3).

The performance evaluation results of the obtained water absorbent composite (3) are shown in Table 1.

Example 4 Partially neutralized aqueous acrylic acid solution (monomer concentration 60% by weight) in which 75 mol% was neutralized with potassium hydroxide 100
0.2 parts by weight of potassium persulfate and N, N'-
After melting parts by weight of methylene bisacrylamide o, oos, dissolved oxygen in the aqueous solution of 7-mer was removed with nitrogen gas.

This aqueous monomer solution was screen printed on a polyethylene non-woven fabric having a thickness of 130 g/m to give a coating weight of 400 g/m.

This nonwoven fabric coated with the aqueous monomer solution was then inserted between two 80'
Clamp for 5 minutes with a steel press plate heated to C.
Polymerization of monomers was carried out.

After polymerization, the nonwoven fabric was taken out from between the press plates and heated to 120°C.
The mixture was dried for 5 minutes in a hot air dryer to obtain a water absorbent composite (4).

Table 1 shows the performance evaluation results of the obtained water absorbent composite (4).

Example 5 The same seven-day aqueous solution used in Example 4 was added to 14 tsubo ff14.
The amount of adhesion is 400g on a 5g/rd hydrophilic pulp cloak.
/rd was gravure printed in a polka dot pattern.

While sandwiching the pulp cloak coated with this monomer aqueous solution between a pair of opposing endless belts made of glass fiber treated with fluororesin,
The pulp mantle was irradiated with microwaves of 0 MHz at an output of 400 W for 30 seconds to polymerize the monomer. At this time, the distance between the belt surfaces was set using an adjuster so that the distance was the same as the thickness of the pulp cloak in its normal state.

Take out the pulp mat after polymerization from between the belt surfaces and
Dry for 5 minutes in a hot air dryer at 20°C to form a water absorbent composite (5
) was obtained.

The performance evaluation results of the obtained water absorbent composite (5) are shown in Table 1.

Example 6 Acrylic acid 20 mol%, potassium acrylate 60 mol%
and potassium 2-methacryloylethanesulfonate 2
After dissolving 0.5 parts by weight of potassium persulfate, 0.003 parts by weight of ethylene glycol diacrylate, and 0.1 parts by weight of hydroxyethyl cellulose in 100 parts by weight of a 50% monomer aqueous solution consisting of 0 mol%, the monomer aqueous solution was dissolved with nitrogen gas. The dissolved oxygen inside was removed.

After immersing a polypropylene non-woven fabric with a basis weight of 30 g/rrr in this 7-summer aqueous solution, the nonwoven fabric whose entire surface was impregnated with the 7-summer aqueous solution was squeezed to reduce the adhesion amount of the 7-summer aqueous solution to 1.
It was set to 50 g/rd.

The nonwoven fabric coated with this 1,000 ml aqueous solution was heated at 80°C through a spacer with the same thickness as its normal thickness.
The monomers were polymerized by clamping them between heated steel press plates for 5 minutes.

The nonwoven fabric after polymerization was taken out from between the press plates and heated at frequency 2.
The nonwoven fabric was dried by irradiating microwaves at 450 MHz and an output of 600 W for 30 seconds to obtain a water absorbent composite (6).

The performance evaluation results of the obtained water absorbent composite (6) are shown in Table 1.

Example 7 Methacrylic acid 15 mol%, sodium methacrylate 45
mol%, sodium 2-acrylamido-2-methylfurohanesulfonate 20 mol% and acrylamide 20
After dissolving 0.2 parts by weight of ammonium persulfate and 0.005 parts by weight of trimethylolpropane triacrylate in 100 parts by weight of a 40% monomer aqueous solution consisting of mol %, dissolved oxygen in the aqueous seven-mer solution was removed with nitrogen gas.

This 7-summer aqueous solution was screen printed on a nonwoven fabric made of polyethylene-polypropylene composite fiber (ES fiber) with a weight of 140 g/rd, and the adhesion amount of the 7-summer aqueous solution was 200 g/I.
It was set as Tr.

The nonwoven fabric coated with the aqueous seven-mer solution was sandwiched between a pair of opposing mirror-finished endless steel belts heated to 80° C. for 5 minutes to polymerize the monomer. At this time, the spacing between the heald surfaces was set using an adjuster so that the spacing was the same as the normal thickness of the nonwoven fabric.

After polymerization, the nonwoven fabric was taken out from between the belt surfaces and heated to 120°C.
The mixture was dried in a hot air dryer for 5 minutes to obtain a water absorbent composite (7).

The performance evaluation results of the obtained water absorbent composite (7) are shown in Table 1.

-Comparative Example 1- In Example 1, instead of sandwiching the nonwoven fabric coated with an aqueous monomer solution between two steel press plates to polymerize the monomer, the nonwoven fabric was placed in a steel plate heated to 60°C under a nitrogen atmosphere. A comparative water absorbent composite (1
) was obtained.

The performance evaluation results of the obtained comparative water absorbent composite (1) were
Shown in the table.

Comparative Example 2 - Instead of sandwiching the nonwoven fabric coated with an aqueous monomer solution between two steel press plates to polymerize the monomer in Example 4, the nonwoven fabric was sandwiched between two steel press plates, and the nonwoven fabric was sandwiched between steel plates heated to 80°C under a nitrogen atmosphere. Comparative water absorbent composite (2) was prepared in the same manner as in Example 4, except that it was placed on top and polymerized for 20 minutes.
I got it.

The performance evaluation results of the obtained comparative water absorbent composite (2) were
Shown in the table.

Comparative Example 3 In Example 6, instead of sandwiching the nonwoven fabric coated with an aqueous monomer solution between two steel press plates to polymerize the monomer, the nonwoven fabric was heated to 80°C under a nitrogen atmosphere. Comparative water absorbent composite (3) was prepared in the same manner as in Example 6, except that it was placed on a plate and polymerized for 20 minutes.
I got it.

The performance evaluation results of the obtained comparative water absorbent composite (3) are
Shown in the table.

Next, examples and comparative examples of the continuous manufacturing method of the present invention will be shown.

Example 8 - Partially neutralized aqueous acrylic acid solution (75 mol % neutralized by potassium hydroxide) (75 mol % 60 wt %) 100
0.2 parts by weight of potassium persulfate and N, N'-
After dissolving 0.005 parts by weight of methylenebisacrylamide, dissolved oxygen in the aqueous solution was removed with nitrogen gas.

Using the apparatus shown in Fig. 1, a polyethylene nonwoven fabric with a basis weight of 30 g/rd was immersed in this 7-sum aqueous solution, and then
The nonwoven fabric whose entire surface was impregnated with the monomer aqueous solution was squeezed to give an adhesion amount of the monomer aqueous solution of 400 g1rd.

Subsequently, the nonwoven fabric to which the aqueous monomer solution had been adhered was moved while being sandwiched between opposing surfaces of a pair of opposing endless steel belts treated with fluororesin shown in FIG. The interval C between the belt surfaces was set using the clearance adjuster shown in FIG. 2 to be the same as the thickness of the nonwoven fabric in its normal state. The residence time during which the heald was clamped between the belt surfaces was 3 minutes, during which time the temperature of the heald surface was maintained at 80° C. under a nitrogen atmosphere to carry out continuous polymerization. The moving speed of the nonwoven fabric was 1 m/min.

Thereafter, the polymerized nonwoven fabric was introduced into the hot air dryer shown in FIG. 1 and continuously dried at 120° C. to obtain a water absorbent composite (8). The residence time in the dried product was 3 minutes.

The performance evaluation results of the obtained water absorbent composite (8) are shown in Table 2.

Example 9 - In the apparatus shown in Fig. 1, a gravure printing machine was installed in place of the immersion tank for the monomer aqueous solution as a device for applying the monomer aqueous solution to the substrate, and an endless steel belt and a steam heater in the polymerization zone were installed. Instead, an endless belt made of glass fiber and a microwave generator with an output of 400 W that generates microwaves with a frequency of 2450 MHz were provided.

Using such a water-absorbing composite production apparatus, first, the same monomer aqueous solution used in Example 8 was mixed with a basis weight of 45 g/
Gravure printing was carried out in a polka dot pattern on a hydrophilic pulp cloak of 400 g/m2.

Subsequently, the pulp mat to which the aqueous monomer solution had adhered was moved while being sandwiched between a pair of opposing endless belts made of glass fiber treated with fluorine resin. The interval C between the belt surfaces was set to be the same interval as the normal thickness of the pulp mat using the clearance adjuster shown in FIG.

Frequency 2 is applied to the pulp mart sandwiched between the belt surfaces.
Polymerization was carried out continuously by irradiating microwaves at 450 MHz and an output of 400 W. Note that the atmospheric temperature during polymerization was 25
℃, and the residence time between the belt surfaces was 3
It was 0 seconds. The movement speed of the pulp mat was 1 m/min.

Subsequently, the pulp mat after polymerization is introduced into a hot air dryer and continuously dried at 120°C, resulting in a water-absorbing composite (9).
I got it. The residence time in the dried product was 3 minutes.

The performance evaluation results of the obtained water absorbent composite (9) are shown in Table 2.

Example 10 Partially neutralized aqueous acrylic acid solution (monomer concentration 40% by weight) in which 75 mol% was neutralized with sodium hydroxide 10
0 parts by weight, 0.2 parts by weight of 2,2''-azobis(NN'-dimethyleneisobutyramidine) dihydrochloride and N,N'
- After dissolving 0.005 parts by weight of methylenebisacrylamide, dissolved oxygen in the aqueous solution of 7-mer was removed with nitrogen gas.

Using the device shown in Figure 3, 30 g/rd
Adhesion to polypropylene non-woven fabric of 1250 g/m
The monomer aqueous solution was sprayed from a spray nozzle so that

Subsequently, the nonwoven fabric to which the aqueous monomer solution had been adhered was moved while being sandwiched between the heated drum roll shown in FIG. 3 and the surface of an endless belt made of glass fiber treated with fluorine resin and covering the half circumferential surface of the drum roll.

The drum roll peripheral surface and the belt surface were set by a clearance adjuster so that the distance between them was the same as the normal thickness of the nonwoven fabric, and the residence time during which the nonwoven fabric was sandwiched between them was 3 minutes. During this time, the temperature of the drum roll was maintained at 60° C. under a nitrogen atmosphere, and polymerization was carried out continuously. The moving speed of the nonwoven fabric was 0.3 m/min.

Subsequently, the polymerized nonwoven fabric was guided under the infrared lamp shown in Fig. 3, and was continuously dried by infrared irradiation.
A water absorbent composite (10) was obtained. Note that the output of the infrared lamp was 400 W, and the irradiation time was 3 minutes.

The performance evaluation results of the obtained water absorbent composite (10) are shown in Table 2.

Example 11 A water-absorbing composite (11) was prepared in the same manner as in Example 10, except that in Example 1O, a polyester nonwoven fabric with a basis weight of 45 g/rd was used instead of the polypropylene nonwoven fabric.
I got it.

The performance evaluation results of the obtained water absorbent composite (11) are shown in Table 2.

Example 12 In Example 8, the same seven-mer aqueous solution as used in Example 1O was used as the monomer aqueous solution), and the amount of the monomer aqueous solution attached to the polyethylene nonwoven fabric was 300 g/m
A water-absorbing composite (12) was obtained in the same manner as in Example 8 except for the following adjustments.

The performance evaluation results of the obtained water absorbent composite (12) are shown in Table 2.

Example 13 - 20 mol% acrylic acid, 60 mol% potassium acrylate
and potassium 2-methacryloylethanesulfonate 2
After dissolving 0.5 parts by weight of potassium persulfate, 0.003 parts by weight of ethylene glycol diacrylate, and 0.1 parts by weight of hydroxyethyl cellulose in 100 parts by weight of a 50% monomer aqueous solution consisting of 0% by weight, the solution was dissolved with nitrogen gas. Dissolved oxygen in the aqueous solution was removed.

Using the apparatus shown in Figure 1, a polypropylene non-woven fabric with a basis weight of 30 g/m was immersed in this aqueous solution of 7-summer, and then the nonwoven fabric whose entire surface was impregnated with the aqueous 7-summer solution was squeezed to reduce the adhesion amount of the aqueous 7-summer solution to 150 g/m. g/rrr.

Subsequently, the nonwoven fabric to which the aqueous solution of 7-mer was adhered was moved while being sandwiched between the surfaces of a pair of opposing endless steel belts treated with fluororesin as shown in FIG. The interval C between the belt surfaces was set using the clearance adjuster shown in FIG. 2 to be the same as the thickness of the nonwoven fabric in its normal state. The residence time between the belt surfaces was 3 minutes, during which time the temperature of the belt surface was maintained at 80° C. under a nitrogen atmosphere to carry out continuous polymerization. The moving speed of the nonwoven fabric was 1 m/min.

Subsequently, an output 6 that generates microwaves with a frequency of 2450 MHz is used instead of the hot air dryer in FIG.
The substrate after polymerization was introduced into a drying room equipped with a 00W microwave generator and was continuously dried to obtain a water-absorbing composite (13). Note that the residence time in the drying chamber was 30 seconds.

The performance evaluation results of the obtained water absorbent composite (13) are shown in Table 2.

Example 14 - 15 mol% methacrylic acid, 45 mol% sodium methacrylate
mol%, sodium 2-acrylamido-2-methylpropanesulfonate 20 mol% and acrylamide 20
After dissolving 092 parts by weight of ammonium persulfate and o, o s parts by weight of trimethylolpropane triacrylate in 100 parts by weight of a 40% monomer aqueous solution consisting of mol %, dissolved oxygen in the aqueous monomer solution was removed with nitrogen gas.

Using the apparatus shown in FIG. 3, an aqueous monomer solution was sprayed from a spray nozzle onto a nonwoven fabric made of polyethylene-polypropylene composite fiber (ES fiber) having a tsubo of 140 g/rd so that the amount of adhesion was 200 g/nf.

Subsequently, the nonwoven fabric to which the aqueous monomer solution was adhered was moved while being sandwiched between the drum roll shown in FIG. 3 and the surface of an endless belt made of glass fiber treated with fluororesin and covering the half circumferential surface of the drum roll. The drum roll circumferential surface and heald surface are
The gap was set by a clearance adjuster so that the thickness was the same as the normal thickness of the nonwoven fabric, and the residence time during which the nonwoven fabric was sandwiched between them was 3 minutes, during which the temperature of the drum roll was maintained under a nitrogen atmosphere. Polymerization was carried out continuously while maintaining the temperature at 80°C. The moving speed of the non-woven fabric is 0.0 per minute.
It was 3m.

Subsequently, the polymerized nonwoven fabric was introduced into a hot air dryer instead of the drying chamber equipped with an infrared lamp in FIG. 3, and was continuously dried at 120° C. to obtain a water absorbent composite (14). The residence time in the dried product was 3 minutes.

The performance evaluation results of the obtained water absorbent composite (14) are shown in Table 2.

Comparative Example 4 - Upper endless belt (
The following operation was carried out in the same manner as in Example 8 using the same apparatus except that IA) was removed.

The same monomer aqueous solution used in Example 8 was
After soaking the polyethylene nonwoven fabric of g/rd,
The nonwoven fabric whose entire surface was impregnated with the monomer aqueous solution was squeezed so that the adhesion amount of the monomer aqueous solution was 400 g/rrf.

Subsequently, the nonwoven fabric to which the aqueous monomer solution was attached was placed on an endless steel belt (lB) treated with fluororesin and moved. The residence time on the belt was 20 minutes, during which time the temperature of the belt surface was increased to 8.
Polymerization was carried out continuously while maintaining the temperature at 0°C. The moving speed of the nonwoven fabric was 0.15 m/min.

Subsequently, the polymerized nonwoven fabric is introduced into a hot air dryer.
It was continuously dried at 120°C to obtain a comparative water absorbent composite (4). Note that the residence time in the dryer was 5 minutes.

The performance evaluation results of the obtained comparative water absorbent composite (4) were
Shown in the table.

Comparative Example 5 - Using the same equipment as shown in Figure 3, except that the endless belt (14) covering the drum roll (13) was removed and a hot air dryer was installed in place of the infrared lamp. The following operation was performed in the same manner as in Example 14.

The same monomer aqueous solution as that used in Example 14) was sprayed from a spray nozzle to a nonwoven fabric made of polyethylene-polypropylene composite fiber (ES fiber) with a basis weight of 40 g/cd so that the adhesion amount was 200 g/nr. The nonwoven fabric to which it was attached was moved along the circumferential surface of the drum roll (13).

The residence time during which the nonwoven fabric was in contact with the drum roll circumferential surface was 20
During this time, the temperature of the drum roll was maintained at 80° C. under a nitrogen atmosphere, and polymerization was carried out continuously. The moving speed of the nonwoven fabric was 0.045 m/min.

Subsequently, the polymerized nonwoven fabric was introduced into a hot air dryer and continuously dried at 120°C, resulting in a comparative water absorbent composite (5).
I got it. Note that the residence time in the dryer was 5 minutes.

The performance evaluation results of the obtained comparative water absorbent composite (5) were
Shown in the table.

Example 15 In the apparatus shown in FIG. 1, a gravure printing machine was provided in place of the dipping tank for the 7-mer aqueous solution as a device for applying the 7-mer aqueous solution to the substrate.

Using such an apparatus, the same monomer aqueous solution used in Example 8 was gravure printed in a polka dot pattern on a rayon nonwoven fabric with a tsubo fi of 80 g/n so that the adhesion amount was 400 g/m.

Subsequently, the nonwoven fabric to which the monomer aqueous solution was attached was moved while being sandwiched between the opposing surfaces of a pair of opposing endless steel healds treated with fluororesin. The distance C between the belt surfaces is determined by the clearance adjuster shown in Figure 2.
The spacing was set to be the same as the normal thickness of the nonwoven fabric.

The residence time between the heald surfaces was 2 minutes, during which the temperature of the belt surface was maintained at 120°C under a nitrogen atmosphere.
The water-absorbing composite (15) is continuously polymerized while maintaining the
I got it. The moving speed of the nonwoven fabric was 25 m/min.

The performance evaluation results of the obtained water absorbent composite (15) are shown in Table 2.

Example 16 Partially neutralized aqueous acrylic acid solution in which 75 mol% was neutralized with sodium hydroxide (7mer concentration 37% by weight) 10
0 parts by weight of sodium persulfate and 0.2 parts by weight of N, N
After dissolving 0.05 parts by weight of '-methylenebisacrylamide, dissolved oxygen in the monomer aqueous solution was removed with nitrogen gas.

Using the apparatus shown in Fig. 1, a polyester nonwoven fabric with a basis weight of 30 g/n was immersed in this monomer aqueous solution.
The nonwoven fabric whose entire surface was impregnated with the monomer aqueous solution was squeezed so that the adhesion amount of the monomer aqueous solution was 80 g/d.

Subsequently, the nonwoven fabric to which the aqueous monomer solution had been adhered was moved while being sandwiched between opposing surfaces of a pair of opposing fluororesin-treated glass fiber endless belts shown in FIG. The interval C between the belt surfaces was set using the clearance adjuster shown in FIG. 2 to be the same as the thickness of the nonwoven fabric in its normal state. The residence time between the belt surfaces was 3 minutes, during which time the temperature of the belt surface was maintained at 100° C. under a nitrogen atmosphere to carry out continuous polymerization. The moving speed of the nonwoven fabric was 1 m/min. Subsequently, the nonwoven fabric after polymerization was introduced into the hot air dryer shown in Figure 1, and was continuously dried at 120°C to obtain a water absorbent composite (16). . The residence time in the drying dish was 3 minutes.

The performance evaluation results of the obtained water absorbent composite (16) are shown in Table 2.

Example 17 In Example 16, 1 part by weight of trimethylolpropane triacrylate O was used in place of N,N'-methylenebisacrylamide, and the amount of adhesion of the 7-mer aqueous solution was reduced to 25%.
g/n (stitched), the temperature of the glass fiber endless belt was maintained at 120° C., and polymerization was carried out in the same manner as in Example 16 to obtain a water absorbent composite (17).

The performance evaluation results of the obtained water absorbent composite (17) are shown in Table 2.

Example 18 Partially neutralized aqueous acrylic acid solution (monomer concentration 35% by weight) in which 75 mol% was neutralized with sodium hydroxide 10
0 parts by weight of 2,2'-azobis(2-amidinopropane) dihydrochloride and 0.4 parts by weight of polyethylene glycol diacrylate (average number of oxyethylene units 8)
．． After dissolving 2 parts by weight, dissolved oxygen in the aqueous solution of 7-mer was removed with nitrogen gas.

Using the apparatus shown in Figure 1, a polyester nonwoven fabric with a basis weight of 30 glrd was immersed in this monomer aqueous solution, and then the nonwoven fabric, the entire surface of which was impregnated with the Neptumer aqueous solution, was squeezed until the adhesion amount of the Neptumer aqueous solution was 300 g/rd. did.

Subsequently, the nonwoven fabric to which the aqueous solution of 7-mer was adhered was moved while being sandwiched between opposing surfaces of a pair of opposing endless steel belts treated with fluororesin shown in FIG. The interval C between the belt surfaces was set using the clearance adjuster shown in FIG. 2 to be the same as the thickness of the nonwoven fabric in its normal state. The residence time between the belt surfaces was 3 minutes, during which time the temperature of the belt surface was maintained at 120° C. under a nitrogen atmosphere to carry out continuous polymerization.

The moving speed of the nonwoven fabric was tom per minute.

Thereafter, the polymerized nonwoven fabric was introduced into the hot air dryer shown in FIG. 1 and continuously dried at 120° C. to obtain a water absorbent composite (18). The residence time in the drying dish was 3 minutes.

The performance evaluation results of the obtained water absorbent composite (18) are shown in Table 2.

Example 19 - 100 parts by weight of a partially neutralized aqueous acrylic acid solution (monomer concentration 60% by weight) in which 60% by mole was neutralized with potassium hydroxide was mixed with 0.0% of 2,2'-azobis(2-amidinopropane) dihydrochloride. 6 parts by weight and N.

After dissolving 0.09 parts by weight of N'-methylenebisacrylamide, dissolved oxygen in the aqueous monomer solution was removed with nitrogen gas.

Using the apparatus shown in FIG. 1, a polyester non-woven fabric with a basis weight of 30 g/rri was immersed in this monomer aqueous solution, and then the non-woven fabric, the entire surface of which was impregnated with the 7-summer aqueous solution, was squeezed to cause the 10-summer aqueous solution to adhere to it, 1r+o.

It was set as glrd.

Subsequently, the nonwoven fabric to which the aqueous monomer solution had been adhered was moved while being sandwiched between the opposing surfaces of a pair of opposing endless steel belts treated with fluororesin shown in FIG. The interval C between the belt surfaces was set using the clearance adjuster shown in FIG. 2 to be the same as the thickness of the nonwoven fabric in its normal state. The residence time between the belt surfaces was 3 minutes, during which time the temperature of the belt surface was maintained at 120° C. under a nitrogen atmosphere to carry out continuous polymerization.

The moving speed of the nonwoven fabric was 1 m/min.

Thereafter, the polymerized nonwoven fabric was introduced into the hot air dryer shown in FIG. 1 and continuously dried at 120° C. to obtain a water absorbent composite (19). The residence time in the drying dish was 3 minutes.

The performance evaluation results of the obtained water absorbent composite (19) are shown in Table 2.

Example 2 - 100 parts by weight of a 40% by weight aqueous solution of 7-mer aqueous solution consisting of 20% by mole of acrylic acid, 60% by mole of sodium acrylate and 20% by mole of ammonium acrylate, 0.2 parts by weight of sodium persulfate and N,N 'After dissolving 4.5 parts by weight of methylenebisacrylamide, dissolved oxygen in the monomer aqueous solution was removed with nitrogen gas.

Using the apparatus shown in Figure 1, add 1 tsubo (1 tsubo) to this 7-sum aqueous solution.
After a 30 g/rrf polyester nonwoven fabric was immersed, the nonwoven fabric whose entire surface was impregnated with the monomer aqueous solution was squeezed so that the amount of the monomer aqueous solution attached was 250 g1rd.

Subsequently, the nonwoven fabric to which the aqueous monomer solution had been adhered was moved while being sandwiched between opposing surfaces of a pair of opposing endless steel belts treated with fluororesin shown in FIG. The interval C between the belt surfaces was set using the clearance adjuster shown in FIG. 2 to be the same as the thickness of the nonwoven fabric in its normal state. The residence time between the belt surfaces was 3 minutes, during which time the temperature of the belt surface was maintained at 110° C. under a nitrogen atmosphere to carry out continuous polymerization.

The moving speed of the nonwoven fabric was 10 m/min.

Thereafter, the polymerized nonwoven fabric was introduced into the hot air dryer shown in FIG. 1 and continuously dried at 120° C. to obtain a water absorbent composite (20). The residence time in the dried product was 3 minutes.

The performance evaluation results of the obtained water absorbent composite (20) are shown in Table 2.

Example 21 Partially neutralized aqueous acrylic acid solution in which 60 mol% was neutralized with sodium hydroxide (7mer concentration 40% by weight) 10
After dissolving 0.2 parts by weight of sodium persulfate and 0.05 parts by weight of ethylene glycol diglycidyl ether in 0 parts by weight, dissolved oxygen in the aqueous monomer solution was removed with nitrogen gas.

Using the apparatus shown in Figure 11, a polyester nonwoven fabric with a basis weight of 60 g/rrr was immersed in this monomer aqueous solution, and then the nonwoven fabric whose entire surface was impregnated with the 7-mer aqueous solution was squeezed to reduce the adhesion amount of the monomer aqueous solution to 400 g/rd. And so.

Subsequently, the nonwoven fabric to which the aqueous monomer solution had been adhered was moved while being sandwiched between opposing surfaces of a pair of opposing endless steel belts treated with fluororesin shown in FIG. The interval C between the belt surfaces was set using the clearance adjuster shown in FIG. 2 to be the same as the thickness of the nonwoven fabric in its normal state. The residence time between the belt surfaces was 1 minute, during which time the temperature of the belt surface was maintained at 150° C. under a nitrogen atmosphere to carry out continuous polymerization.

The moving speed of the nonwoven fabric was 50 m/min.

Thereafter, the polymerized nonwoven fabric was introduced into the hot air dryer shown in FIG. 1 and continuously dried at 120° C. to obtain a water absorbent composite (21). The residence time in the dried product was 3 minutes.

The performance evaluation results of the obtained water absorbent composite (21) are shown in Table 2.

Example 22 Partially neutralized aqueous acrylic acid solution (monomer concentration 40% by weight) 85 mol % neutralized with sodium hydroxide 10
0 parts by weight of N,N'-methylenebisacrylamide.
0.5 parts by weight of sodium persulfate, 0.2 parts by weight of sodium peroxide, and 0.2 parts by weight of hydrogen peroxide, then 10 parts by weight of hydrophilic pulp fibers with a fiber length of 50 μm were added, and then nitrogen gas was added to the solution. of dissolved oxygen was removed.

Using the apparatus shown in Figure 1, a polyester nonwoven fabric with a basis weight of 30 g/I is immersed in this monomer aqueous solution, and then the nonwoven fabric whose entire surface is impregnated with the monomer aqueous solution is squeezed to reduce the adhesion amount of the 7-mer aqueous solution to 300 g/I. It was made into a CD.

Subsequently, the nonwoven fabric to which the aqueous monomer solution had been adhered was moved while being sandwiched between opposing surfaces of a pair of opposing endless steel belts treated with fluororesin shown in FIG. The interval C between the belt surfaces was set using the clearance adjuster shown in FIG. 2 to be the same as the thickness of the nonwoven fabric in its normal state. The residence time between the belt surfaces was 3 minutes, during which time the temperature of the belt surface was maintained at 120° C. under a nitrogen atmosphere to carry out continuous polymerization.

The moving speed of the nonwoven fabric was 10 m/min.

Subsequently, the polymerized nonwoven fabric was introduced into the hot air dryer shown in FIG. 1 and continuously dried at 120° C. to obtain a water absorbent composite (22). The residence time in the dried product was 3 minutes.

The performance evaluation results of the obtained water absorbent composite (22) are shown in Table 2.

Example 23 Acrylic t1120 mol%, sodium acrylate 65
mol%, 15 mol% of methoxypolyethylene glycol acrylate (average number of oxyethylene units 1O) aqueous solution of 7mer (7mer concentration 50% by weight) 100
0.35 parts by weight of IJum and N,
0.05 parts by weight of N'-methylenebisacrylamide was dissolved, and then dissolved oxygen in the aqueous solution of 7-mer was removed with nitrogen gas.

Using the apparatus shown in Fig. 1, a polyester nonwoven fabric with a basis weight of 30 g/rd was immersed in this 7-sum aqueous solution, and then
The nonwoven fabric whose entire surface was impregnated with the aqueous 7-summer solution was squeezed so that the amount of the 7-sum aqueous solution deposited was 200 g/rd.

Subsequently, the nonwoven fabric to which the aqueous solution of 7-mer was adhered was moved while being sandwiched between the opposing surfaces of a pair of opposing endless steel healds treated with fluororesin shown in FIG. The interval C between the belt surfaces was set using the clearance adjuster shown in FIG. 2 to be the same as the thickness of the nonwoven fabric in its normal state. The residence time between the belt surfaces was 5 minutes, during which time the temperature of the belt surface was maintained at 100° C. under a nitrogen atmosphere to carry out continuous polymerization.

The moving speed of the nonwoven fabric was 0.5 m/min.

Thereafter, instead of leading the polymerized nonwoven fabric to the hot air dryer shown in Figure 1, it was led to a drying room equipped with a 3kW high-pressure mercury lamp, and was continuously dried by irradiating ultraviolet rays to form a water-absorbing composite (23 ) was obtained. The distance between the nonwoven fabric and the mercury lamp is 10cm.
The residence time was 15 seconds... The performance evaluation results of the obtained water absorbent composite (23) are shown in Table 2.

Example 24 - The nonwoven fabric after polymerization in Example 16 was irradiated with ultraviolet rays and dried in the same manner as in Example 23 to obtain a water absorbent composite (24).

The performance evaluation results of the obtained water absorbent composite (24) are shown in Table 2.

Example 25 In Example 16, the amount of monomer aqueous solution attached was 200
A water-absorbing composite (25) was obtained in the same manner as in Example 16, except that polymerization was carried out by using glrd and maintaining the temperature of the heald surface at 120°C.

The performance evaluation results of the obtained water absorbent composite (25) are shown in Table 2.

Comparative Example 6 In Example 15, the upper bell) IA was removed, the temperature of the belt surface was maintained at 120°C, and the monomers attached to the nonwoven fabric were polymerized in a nitrogen atmosphere. ) was obtained. The residence time on the belt was 5 minutes, and the moving speed of the nonwoven fabric was 10 m/min.

The performance evaluation results of the obtained comparative water absorbent composite (6) were
Shown in the table.

Comparative Example 7 In Example 16, the upper bell) IA was removed, the temperature of the belt surface was maintained at 100°C, and the monomer attached to the nonwoven fabric was polymerized in a nitrogen atmosphere, and then the temperature was maintained at 120°C.
The mixture was dried in a hot air dryer to obtain a comparative water absorbent composite (7). The residence time on the belt and in the drying tray was 5.
The moving speed of the nonwoven fabric was 0.6 m/min.

The performance evaluation results of the obtained comparative water absorbent composite (7) were
Shown in the table.

Comparative Example 8 The upper belt IA in Example 21 was removed, the temperature of the belt surface was maintained at 150°C, and the monomers attached to the nonwoven fabric were polymerized in a nitrogen atmosphere to form a comparative water absorbent composite (8). Obtained. The residence time on the belt was 2 minutes, and the moving speed of the nonwoven fabric was 25 m/min.

The performance evaluation results of the obtained comparative water absorbent composite (8) were
Shown in the table.

〔Effect of the invention〕

According to the production method of the present invention, a water-absorbing composite in which the water-absorbing polymer is firmly fixed without falling off the base material can be easily and efficiently produced using a simple device.

According to the continuous production method of the present invention, such a water-absorbing composite can be continuously produced easily and efficiently.

The manufacturing apparatus of the present invention makes it easy to set the distance between the polymerization-inactive surfaces, and can easily carry out the continuous manufacturing method described above.

In addition, the water-absorbing composite produced by the method of the present invention has excellent water-absorbing ability, and since the amount of residual monomer in the polymer is extremely low, there is no adverse effect on the human body or the environment.
It can be used in a wide range of fields that require water absorption and water retention, such as sanitary materials, food products, civil engineering, building materials, electricity, and agriculture.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing one embodiment of an apparatus for carrying out the continuous manufacturing method of the present invention, FIG. 2 is a schematic explanatory diagram of a part thereof, and FIG. FIG. 2 is a schematic explanatory diagram showing another embodiment of an apparatus for carrying out a manufacturing method according to the present invention. IA, IB... Endless belt 3A, 3B...
Steam heater 4... Nanatsumar aqueous solution 6 River hot air dryer 8... Winding roll 9... Support roll I
O... Base material 11... Water-absorbing composite 12... Spray nozzle 13... Drum roll 14... Endless belt 15... Infrared lamp 2o...
Clearance adjuster C...Clearance ♂ff Dera 3 figure agent Patent attorney Takehiko Matsumoto

Claims (1)

[Scope of Claims] 1. After applying an aqueous solution containing a water-soluble ethylenically unsaturated monomer and a water-soluble radical polymerization initiator that can be converted into a water-absorbing polymer by polymerization to a base material, the base material to which the aqueous solution has been applied A method for producing a water-absorbing composite, wherein the monomer is polymerized while the monomers are sandwiched between opposing polymerization-inactive surfaces to produce a water-absorbing composite. 2. The method for producing a water-absorbing composite according to claim 1, wherein after polymerizing the monomer, the base material on which the produced water-absorbing polymer is fixed is dried in gas. 3 While moving the substrate, (1) an application area where an aqueous solution containing a water-soluble ethylenically unsaturated monomer and a water-soluble radical polymerization initiator that can be converted into a water-absorbing polymer by polymerization is applied to the substrate; (2) A method for continuous production of a water-absorbing composite, in which monomers are sequentially passed through polymerization zones in which a substrate is sandwiched between opposing polymerization-inert surfaces. 4. The method for continuously producing a water-absorbing composite according to claim 3, wherein, after the polymerization zone, the base material is passed through a drying zone where the base material is heated while being held in a gas. 5. A substrate coated with an aqueous solution containing a water-soluble ethylenically unsaturated monomer and a water-soluble radical polymerization initiator that can be converted into a water-absorbing polymer by polymerization is (1) sandwiched between opposing polymerization-inactive surfaces. (2) a drying zone where the monomer is heated while being held in a gas; and (2) a drying zone where the monomer is heated while being held in a gas. 6. The drying area blows hot air while holding the substrate in the gas by rotatable support rolls and/or support belts.
6. The continuous manufacturing method according to claim 4, wherein the heating is performed using microwaves, infrared rays, or ultraviolet rays. 7. The manufacturing method according to any one of claims 1 to 6, wherein the water-soluble ethylenically unsaturated monomer contains (meth)acrylic acid or a salt thereof as a main component. 8. The manufacturing method according to claim 1, wherein the monomer is polymerized by heating the base material. 9. The manufacturing method according to claim 8, wherein the heating is performed to a temperature in the range of 50 to 150°C. 10. The manufacturing method according to claim 8, wherein the heating is performed using microwaves. 11. The manufacturing method according to any one of claims 1 to 10, wherein the base material is a fiber base material. 12. The manufacturing method according to any one of claims 1 to 11, wherein the aqueous solution also contains a water-soluble crosslinking agent. 13. The manufacturing method according to any one of claims 1 to 12, wherein the polymerization-inactive surface is a fluororesin-treated or mirror-finished surface. 14 The following means (
1) and (2), and while continuously moving the base material, an aqueous solution containing a water-soluble ethylenically unsaturated monomer and a water-soluble radical polymerization initiator that can be converted into a water-absorbing polymer by polymerization is applied to the base material. An apparatus for producing a water-absorbing composite, in which the monomer is polymerized while the base material is sandwiched between opposing polymerization-inactive surfaces, and the water-absorbing polymer is fixed to the base material. (1) Application means for applying the aqueous solution to a moving substrate. (2) A substrate to which the aqueous solution is attached, the substrate having opposing polymerization-inactive surfaces and means for setting a gap between the polymerization-inactive surfaces at an interval corresponding to the thickness of the substrate. A polymerization means for polymerizing the monomer while the water-absorbing polymer is passing through the gap and fixing the water-absorbing polymer to the base material. 15. The manufacturing apparatus according to claim 14, wherein the polymerization means also includes means for heating the base material. 16. The manufacturing apparatus according to claim 14 or 15, further comprising a winding means for winding up the obtained water absorbent composite after the polymerization means. 17. The manufacturing apparatus according to claim 14 or 15, further comprising drying means for heating in gas while moving the base material to which the water-absorbing polymer is fixed next to the polymerization means. 18. The manufacturing apparatus according to claim 17, wherein the drying means includes at least one of a hot air blowing source, a microwave application means, an infrared ray irradiation means, and an ultraviolet irradiation means. 19. The manufacturing apparatus according to claim 18, wherein the drying means also includes rotatable support rolls and/or support belts for holding the moving substrate in gas. 20. Claim 17, further comprising a winding means for winding up the dried water-absorbing composite next to the drying means.
20. The manufacturing apparatus according to any one of 19 to 19.