JPS6063209A - Manufacture of water-swellable crosslinked polymer - Google Patents

Abstract

PURPOSE:To obtain the titled polymer with high water-swellability and transparency, by radical polymerization of a mixture of acrylamide and crosslinkable monomer in the presence of water followed by drying the resultant polymer at specific temperatures. CONSTITUTION:A monomer mixture of (A) 100mol of a (meth)acrylamide [pref. (meth)acrylamide] and (B) 0.01-5mol of a crosslinkable monomer [pref. N,N'- methylenebis(meth)acrylamide] are polymerized in an aqueous medium using (C) radical polymerization initiator (e.g., potassium persulfate) to prepare a water- swellable gel-like crosslinked polymer. Said polymer in then dried at 105-150 deg.C to obtain the objective polymer. Said polymerization is preferably carried out to a conversion >=85%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a crosslinked polymer with excellent water swelling properties and transparency from (meth)acrylamides and a crosslinkable monomer.

Water-swellable crosslinked polymers formed from (meth)acrylamides and crosslinkable monomers are used in applications such as hydroponic soil and soil conditioners. When used for any of these purposes, it is required to have excellent water swelling properties, and when used as artificial soil for hydroponic cultivation, it must also have excellent transparency. required.

Conventionally, as a method for producing water-swellable crosslinked polymers from (meth)acrylamides and crosslinkable monomers, acrylamide and N,N'-methylenebisacrylamide were mixed in water/8 liquid in the presence of a radical polymerization initiator. By polymerizing the water-swelling gel-like crosslinked polymer to i! I. JP-A-56-1'45908 proposes a method of drying the gel-like crosslinked polymer at a temperature below 100°C. However, even if a crosslinked polymer is produced by this method, the water swelling property of the crosslinked polymer is not sufficient, and there is a drawback that the crosslinked polymer cannot exhibit sufficient performance even when used for the above-mentioned purposes.

The present inventors investigated a method for producing a water-swellable crosslinked polymer with excellent water-swellability and transparency from a monomer mixture consisting of (meth)acrylamides (al) and a crosslinkable monomer (b). As a result, the inventors discovered that the above object could be achieved by drying a water-swollen gel-like crosslinked polymer obtained by radical polymerization of the monomer mixture in the presence of water at a specific temperature, and thus arrived at the present invention. .

That is, the present invention provides (meth)acrylamides (al
and the (meth)acrylamide IHa) in an amount of 0.01 to 5 mol per 100 mol of the crosslinking monomer (
A water-swelling gel-like crosslinked polymer is obtained by polymerizing the monomer mixture consisting of b) in the presence of water using a radical polymerization initiator, and the water-swelling gel-like crosslinked polymer is heated at a temperature of 105 to 150°C. The gist of this invention is a method for producing a water-swellable crosslinked polymer, which is characterized by drying at a temperature of .

In the method of the present invention, (meth)acrylamide Jjl (al is acrylamide, methacrylamide, or an N-alkyl substituted product thereof, and specifically, acrylamide, methacrylamide, N- Methylacrylamide 1”, N,N-dimethylacrylamide, N-methylmethacrylamide, N,N
-Dimethylmethacrylamide and the like can be exemplified. Among these (meth)acrylamides,
Acrylamide or methacrylamide is preferred.

In addition, the crosslinkable monomer (b) constituting the raw material monomer mixture
Specifically, N,N'-methylenebis(meth)acrylamide, N,N'-ethylenebis(meth)acrylamide, N,N'-propylenebis(meth)acrylamide, N,N'-hexamethylenebis( meth)acrylamide, bis(meth)acrylamide F such as N,N'-phenylenebis(meth)acrylamide, ethylene bis(meth)acryle-1-, propylene bis(meth)acrylate, hexamethylene bis(meth)acrylate Examples include bis(meth)acrylates such as diethylene glycol bis(meth)acrylate, triethylene glycol bis(meth)acrylate, and polyethylene glycol bis(meth)acrylate, and even if two or more types of mixed components are used, I can't help it. Among these crosslinkable monomer components, N,N'-methylenehis(meth)acrylamide component is particularly preferred.

The monomer mixture used in the method of the present invention may be composed only of the above-mentioned essential monomers, or may further include other unsaturated monomers that are soluble in copolymerization (even if it contains a small amount of C1). No problem. The copolymerizable unsaturated monomer (C) includes common unsaturated monomers such as acrylic acid, methacrylic acid, acid anhydrides, salts or esters of these acids, vinyl acetate, styrene, and vinyltoluene. In addition, in order to impart algae-proofing properties, mildew-proofing properties, and coloring properties to the finally obtained water-swellable crosslinked polymer, the monomer mixture may contain a vinyl bond. Adding unsaturated monomer components such as triazine derivatives, vinyl bond-containing organic tin compounds, anti-algae unsaturated monomers, anti-mildew unsaturated monomers, and young unsaturated monomers, Copolymerization is also possible.

Regarding the composition of the monomer mixture used in the method of the present invention, the proportion of the crosslinking monomer (bl) is in the range of C6 old to 5 mol per 100 mol of the (meth)acrylamide (al). If the proportion of the crosslinkable monomer (BL) is less than 0.01 mole, the water-swellable crosslinked polymer becomes too soft. Therefore, when used as artificial soil for hydroponic cultivation, it becomes unable to support plants, and if the amount exceeds 5 mol, the water-swellable crosslinked polymer becomes extremely cloudy and its transparency decreases, making it difficult to use in the above-mentioned applications. There is a drawback that the appearance deteriorates when used.In addition, the proportion of the other copolymerizable unsaturated monomer (C) to be copolymerized as necessary is usually 0.01 to 60 mol, preferably ranges from 1 to 40 moles.

The radical polymerization initiator used in the method of the present invention is water-soluble, specifically ammonium persulfate,
Examples include potassium persulfate, 1-lium persulfate triethanolamine, and 3-dimethylaminopropionitrile, and a mixture of two or more of these may also be used. The ratio of the radical polymerization initiator used is 1 to 1 of the (meth)acrylic acid amide II ta+.
0.00 mol, the current is 0.001 to 10 mol, preferably 0.00 mol. +11 to 5 moles.

In the method of the invention, the monomer mixture is polymerized in the presence of water to form a water-swollen gel-like crosslinked polymer.

The polymerization reaction can be carried out in the form of an aqueous solution of the monomer mixture, or can be dispersed by stirring a mixture consisting of an aqueous solution of the monomer mixture and a solvent that forms phase separation with the aqueous solution under polymerization conditions. A system can also be formed to produce a water-swollen gel-like crosslinked polymer. The proportion of water to be used in this case is arbitrary as long as the monomer mixture forms an aqueous solution, but 100 to 5000 parts by weight, preferably 200 to 5000 parts by weight of energized per 0 parts by weight of the tl', Bt suspension mixture. The range is from 2000 to 2000 and 0 to 2000. The temperature during the polymerization reaction is in the range of 40 to 150° C., preferably 50 to 100° C., and the time required for the polymerization reaction is in the range of 1 to 600 minutes, preferably 3 to 300 minutes. In the method of the present invention, in order to obtain a crosslinked polymer with excellent water swelling properties by drying at a specific temperature described below, it is preferable to increase the polymerization rate in the polymerization reaction, and preferably the polymerization rate is 80. %
Above, the polymerization reaction is particularly preferably carried out until it reaches 85% or more.

In the method of the present invention, the water-swellable gel-like crosslinked polymer produced by the polymerization reaction can be obtained in various shapes, for example, by the following methods. Its shape is cylindrical, prismatic (square, rectangular parallelepiped, triangular prism, square prism, pentagonal prism,
(hexagonal prism, etc.), conical shape, pyramidal shape, spherical shape, donut shape, hollow tubular shape, hollow prismatic shape, foot shape, etc.

(1) A raw material aqueous solution containing a monoplane rib and a radical polymerization initiator is passed through a pipe having a desired shape while being heated.
A method in which various columnar shapes are obtained by extruding the resulting water-swelling gel-like crosslinked polymer and cutting it with a cutter. At that time, the inner surface of the polymerization tube may be coated with a fluororesin such as a polyfluorinated ethylene polymer to improve the 1-h property of the gel-like crosslinkable polymer during extrusion. .

(2) The raw water/8 liquid is polymerized by flowing through a thick tube under heating, and the resulting water-swollen gel-like crosslinked polymer is passed through a mesh-like blade of a desired shape into a plurality of columnar bodies. 111, and a method of cutting 1η of columnar bodies of various shapes by cutting this with a cutter. At that time, the inner surface of the polymerization tube and the surface of the mesh-like blade were coated in the same manner as described above. You may.

(3) A method of obtaining a desired shaped body by LJJ cutting a lump (ingot) obtained by bulk polymerizing a raw material aqueous solution.

(4) A method of polymerizing raw water/liquid into a plate-like material and cutting it into a desired shape with a mesh-like blade or No. J cutter.

(5) Raw water? A method of polymerizing a liquid on a held container having a desired shape of polymerization type.

(6) A method of obtaining a nearly spherical shaped body by stirring a mixture consisting of a raw material aqueous solution and a solvent that forms AI (compatible with the aqueous solution under polymerization conditions).

At this time, the shape and size of the water-swellable gel-like crosslinked polymer can be changed as appropriate by changing the type of solvent, the proportion used, stirring conditions, temperature, etc.

In addition to producing the water-swellable gel-like crosslinked polymer of the above-mentioned shape, the water-swellable gel-like crosslinked polymer produced according to the purpose of use of the water-swellable crosslinked polymer can be crushed and powdered. Alternatively, granules can also be obtained.

In the method of the present invention, in the above formulation, δI! d'Jl water-swelled gel-like cross-linked polymer has a molecular weight of 105 to 150
It is necessary to dry at a temperature in the range of 110 to 140'C, more preferably at a temperature in the range of 110 to 140'C. If the drying temperature is lower than 105°C, the water swelling property of the resulting crosslinked polymer will be significantly reduced, and if it is higher than 150°C, the crosslinked polymer will become extremely cloudy when swollen with water, and its transparency will be significantly reduced. Becomes damaged.

The water-swellable crosslinked polymer obtained by the method of the present invention has excellent water-swellability and transparency, and can be used for various purposes in the form of the above-mentioned shapes, and can be further used after drying depending on the purpose. 5) It can be crushed and used as a 1'5) shaped body or granulated body.

Next, the present invention will be specifically explained using examples.

Examples 1 to 8 A homogeneous solution having the composition shown in Table 1 was prepared into a tube with an inner diameter of 7 mm and a length of 300
The mixture was continuously supplied to a Teflon tubular polymerization vessel (mm), and polymerization was carried out at a temperature of 90° C. and a polymerization time of 8 minutes. The obtained strand-shaped water-swellable gel-like crosslinked polymer having a diameter of 7 mm was continuously cut into a length of 7 mm. The obtained water-swellable gel-like crosslinked polymer was washed in running water for 8 hours to remove the monomer remaining in the water-swellable gel-like crosslinked polymer. After washing, the water-swelled gel-like crosslinked polymer was dried in a hot air dryer at the temperature shown in Table 1 for 8 hours. Table 1 shows the physical properties of the resulting semitransparent pellet water-swellable crosslinked polymer.

These pellet-like water-swellable crosslinked polymers were immersed in water containing diluted liquid fertilizer (Beaugland's solution) to obtain transparent water-swellable gel-like crosslinked polymers containing fertilizer. 400 ml of the swollen gel-like crosslinked polymer was placed in a bowl-shaped glass container with a diameter of 130 mm and a height of 140 n+n+, and approximately 10 cm seedlings of begonia and St. Boria were transplanted and cultivated in a room with sunlight, while supplementing with a dilute aqueous solution of liquid fertilizer. However, each of these plants grew smoothly even after 4 months.

Comparative Examples J~8 A homogeneous solution having the composition shown in Table 2 was polymerized in the same manner as in Example 1, washed with running water for 8 hours, and then dried for 8 hours in a hot air dryer at the temperature shown in Table 2. did. Table 2 shows the physical properties of the resulting semitransparent pellet water-swellable crosslinked polymer.

Comparative Examples 9 to 11 A homogeneous solution having the composition shown in Table 3 was polymerized in the same manner as in Example 1, washed in running water for 8 hours, and then dried in a hot air dryer at 160°C for 8 hours. The polymer then foamed and became popcorn-shaped. This popcorn-shaped water-swellable cross-linked polymer absorbed water by immersing it in water and became a water-swellable gel-like cross-linked polymer, but the gel became cloudy over a wide area.
It also contained a large amount of bubbles and had a noticeably dull appearance. Table 3 shows the water swelling ratio of the water-swellable crosslinked polymer.

Procedural amendment dated October 27, 1980, Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office1, Indication of the case, Patent Application No. 16921'9, filed in 1982,2, Name of the invention, Process for producing water-swellable crosslinked polymer3, ? Patent applicant (58B) Mitsui Petrochemical Industries Co., Ltd. Representative: Seiki Nakano 4, Agent: 3-2-5-5 Kasumigaseki, Chiyoda-ku, Tokyo 100, Japan Date of amendment order None 6.Detailed description of the invention to be amended: Column 7, Contents of the amendment (1) "Maleic acid" is added after "Methacrylic acid," in the previous section of the specification, page 5, lines 7-8. .

(2) From page 6, line 14 to page 7, line 2 of the specification, “Specifically, ammonium persulfate, potassium persulfate,
It is preferably in the range of 0.01 to 5 mol. "Specifically, ammonium persulfate, potassium persulfate, thorium persulfate, etc. can be exemplified.
It can also be used as a mixture of two or more of these. The proportion of the radical polymerization initiator used is usually 0.001 to 10 mol, preferably 0.01 to 5 mol, per 100 mol of the (meth)acrylic acid amide (a+). If necessary, amines such as triethanolamine and 3-dimethylaminopropionitrile may be used in combination with the initiator.

(3) Next to Table 6 on page 16, the following “Example 9” and “
Comparative Example 12” is added.

[Example 9] 88 g of acrylamide, 3 g of acrylic acid, and 2.0 g of N,N-methylene acetate acrylamide were added to 900 g of water, and 0.1 g of ammonium persulfate was added thereto, melted and homogenized. As. This has an inner diameter of 7cm and a length of 300n.
Continuously feed to +m Teflon tubular polymerization vessel,
Polymerization was carried out at a temperature of 90° C. and a polymerization time of 10 minutes. The obtained strand-shaped water-swellable gel-like crosslinked polymer having a diameter of 7 mm was continuously cut into a length of 71 um. The obtained water-swelled gel-like crosslinked polymer was washed in running water for 8 hours to remove the monomer remaining in the water-swelled gel-like crosslinked polymer. After washing, the water-swelled gel-like crosslinked polymer was dried in a hot air dryer at 125°C for 15 hours. The water swelling rate of the obtained translucent pellet-shaped swellable crosslinked polymer at room temperature was 120 times its own weight.

Comparative Example 12 A homogeneous/8 solution having the same composition as in Example 9 was polymerized in the same manner as in Example 9, washed in running water for 8 hours, and then dried in a hot air drier at 60°C. The water swelling rate of the water-swellable cross-linked polymer in the form of translucent pellets (1-1) subjected to f-H at room temperature is 80% of its own weight.
It was double that. ” Procedural amendment January 2, 1948 Kazuo Wakasugi, Commissioner of the Japan Patent Office 1. Description of the case 1982 Patent Application No. 169219 2. Name of the invention Process for producing water-swellable crosslinked polymer 3. Amendment Patent applicant (58B) Mitsui Petrochemical Industries, Ltd. 4, Agent 'i'+00 3-2-5, Kasumigaseki, Chiyome-ku, Tokyo Date of amendment order 6 Amendment Detailed Description of the Invention in the Target Specification Column 7 Contents of the Amendment (1) ``In the first ON6 line of the original specification can be obtained.

”, then add a new line and add the following sentence.

[The water-swellable gel-like crosslinked polymer is a water-swellable gel-like crosslinked polymer consisting of only two essential components, the (meth)acrylamide component unit (a) and the crosslinkable monomer component unit (b). In addition to the above two essential components, if necessary, unsaturated monomers such as acrylic acid, methacrylic acid, maleic acid, anhydrides, salts or esters of these acids, vinyl acetate, styrene, vinyl toluene, etc. There is no problem even if it contains ht ffi minute unit (c). These component units can be contained by copolymerization as described above, or the (meth)acrylamide component unit (a), the crosslinkable monomer component unit (b), and the above-mentioned if necessary It can also be contained by hydrolyzing or saponifying a water-swellable gel-like crosslinked polymer composed of other unsaturated single body component units (c) that may be contained. (2) Original specification, page 11, line 2, 1. '', add the following sentence without starting a new line.

[The density and degree of swelling of the dried crosslinked polymer are the values measured by the following method.

(1) Density The constant weight (ft) (Wg) of the dry double coalesce is 2
The samples were collected in a 5mj7 vicinometer. The vicinometer containing the polymer was then placed in a constant temperature bath at 24°C and filled with toluene at 24°C. The toluene volume (V) was determined from the toluene weight required for this, and was calculated using the following formula.

(2) Swelling degree; constant weight of dry polymer (' W 1
g) was collected and immersed in water at 24 degrees for 24 hours to sufficiently swell the polymer.

Then remove excess water and swell. Measure the weight (W2g) of the moisturizing gel-like material. It was calculated using the following formula.

Swelling degree (24°C) -w2-wl 1 ”

Claims (1)

[Claims] (1) 0.0% per 100 mol of (meth)acrylamide (al) and the (meth)acrylamide fil.
A water-swellable gel-like crosslinked polymer is obtained by polymerizing a monomer mixture consisting of the crosslinkable monomer (b) in a range of 01 to 5 moles using a radical polymerization initiator in the presence of water, and A method for producing a water-swellable crosslinked polymer, which comprises drying the water-swellable gel-like crosslinked polymer at a temperature in the range of 105 to 150°C.