JPS5811140A - High water-absorbing laminate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminate including a superabsorbent polymer layer.

Films made from highly water-absorbent polymers are cut into thin strips and are expected to be used as water retention agents for plants, i.e., as a substitute for water stains, but since they are flat in shape, they can be used to absorb water and used in pots, etc. When filled, the air permeability is low, and the feel is also unsatisfactory, making it hard to say that it resembles a natural water gob.

The present invention solves these difficulties.

As shown in FIG. 1, the superabsorbent laminate of the present invention is made of a thin layer base material (image of Al and superabsorbent polymer layers), and has the following excellent effects.

(b) When the cut material is soaked with water, it curls into a spiral shape (see Figure 2) or a spiral shape (see Figure 3), and its apparent volume increases significantly.

(Naka) Therefore, even if you suppress this, you will develop a resilience and have what is called a waist.

(c) Due to its curled shape, it has excellent not only water retention but also air permeability, so it is extremely suitable as an evaporation prevention material for plants, a plant transportation material, a plant growing soil, and a soil water retention material.

2) High strength even when water is absorbed.

(e) Favorable appearance and feel.

It has been discovered that when a super absorbent polymer layer () containing an inorganic or organic material is used, the appearance, feel, and texture are further improved in addition to the above effects, and the present invention has been made. I was able to complete it.

The thin layer base material (A) used in the present invention includes a polyolefin film, a nylon film, a polyester film, a polyvinyl alcohol film,
Films such as ethylene-vinyl alcohol copolymer film, polyvinyl chloride film, and cellulose film are mentioned, as well as split cloth, textile fabric, nonwoven fabric, which is made by stacking split films vertically and horizontally and bonding them together.
Net, paper, aluminum foil, etc. are also used. Among these, polyvinyl alcohol (including modified polyvinyl alcohol) films and uniaxially or biaxially stretched polyvinyl alcohol films have excellent adhesion with the superabsorbent polymer layer (A); It is especially good in terms of feel and texture when water is absorbed.

Any conventionally known superabsorbent polymers can be used as the polymer constituting the superabsorbent polymer layer (@), but they are still water-soluble at the time of layer formation and are highly Particularly preferred are polymers that exhibit water absorption properties. Examples of such polymers include vinyl ester-unsaturated carboxylic acid (or derivatives thereof) copolymer silicide, that is, unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, or esters and salts thereof, maleic acid, Typical examples include polyvinyl alcohol modified with unsaturated dicarboxylic acids such as fumaric acid and itaconic acid, or their partial or complete esters, salts, anhydrides, and the like. The amount of modification of unsaturated carboxylic acid (or its derivative) is 0.5 to 5
A suitable content is 0 mol%, especially 1 to 10 mol%.

Note that this modified polyvinyl alcohol is often used in combination with polyvinyl alcohol, for example, the above-mentioned modified polyvinyl alcohol and polyvinyl alcohol? i='flt
It seems to be used at a ratio of about f99-20:1-80.

Other polymers include bonito [, polyethylene oxide, polyvinylpyrrolidone, sulfonated polyethylene, saponified starch-(meth)acrylonitrile copolymer, hydrolyzed polyacrylamide, polyacrylate, starch-(meth)acrylate] Examples include copolymers, saponified ethylene-vinyl ester-unsaturated carboxylic acid (or derivatives thereof) copolymers, pycnized hydroxyacrylate-acrylamide copolymers, and crosslinked products thereof.

The method of providing the highly water-absorbing polymer layer (I3) on the thin-layer base material (4) is as follows: (1) Applying a solution of a polymer that potentially has high water-absorbing capacity on the thin-layer base material (3). After , casting and extrusion coating, high water absorption ability imparting treatment (thermal I18! treatment, acid treatment, radiation.

electron beam irradiation, etc.).

(2) A polymer film potentially having high water absorption capacity is prepared, and this and the thin layer base material η) are adhered by means such as an adhesive or heat sealing, and then a high water absorption capacity imparting treatment is performed.

(3) A thin layer of a polymer film with high water absorption capacity (
4) Glue.

Methods such as these are adopted.

It is extremely desirable to incorporate various inorganic or organic materials into the superabsorbent polymer layer ω) during its manufacture. This is because a more favorable appearance, touch, and texture can be obtained.

Inorganic materials include perlite, zeolite, sand, pumice, slag, volcanic ash, vermiculite, culture soil, silicic anhydride, calcium carbonate, magnesium carbonate, paricum carbonate, clay, diatomaceous earth, talc, feldspar powder, titanium oxide, alumina, stone base, Examples include mineral fibers.

Examples of organic materials include peat moss, bulbs, fibers, leaf mold, and shredded plants.

The amount of organic or inorganic material added to the superabsorbent polymer can be selected from a wide range, but it is desirable that the latter be about 20 times or less, particularly 0.01 to 15 times the former.

The laminate consisting of the thin base material and the super absorbent polymer can be used as is or cut into appropriate sizes.

When cut into thin strips and brought into contact with water, it curls into a spiral or spiral shape, which is typical of the prefecture, so it can be used as a substitute for water stains, as a water retention material, as a soil improvement material, and for vegetables, fish, and shellfish. It is particularly useful for applications such as freshness-preserving materials and artificial baits. When cut into small pieces, they curl and increase in bulk when they come into contact with water and enclose air, making them useful for applications such as water retention materials and soil improvement materials.

Next, the laminate of the present invention will be further explained by giving an example. "1 part" and "96" below are expressed on a weight basis unless otherwise specified.

Example 1 1750 parts of monomethyl maleate-modified polyvinyl alcohol obtained by saponifying 98 mol% of the vinyl acetate component of a monomethyl maleate-vinyl acetate copolymer with a monomethyl maleate content of 5 mol%, a polymerization degree of 1700, and a saponification degree of A 20% aqueous solution was prepared by dissolving 750 parts of 99.7 mol% polyvinyl alcohol in 10,000 parts of water, and 500 parts of perlite was added thereto and mixed.

A two-wheeled stretched polyvinyl alcohol film with a thickness of 14 μm was placed on the release paper, and the mixture was cast onto it.
After being placed in the dryer at 00℃ for about 10 minutes, it became 0.5 m thick.
A sheet-like laminate was obtained, and when drying was completed, the laminate was heat-treated in a dryer at 155°C for 1.5 hours to give it a high water absorption property, and then placed in a steam tank. It softened for about 1 minute.

The thus obtained laminated sheet has a medium size of 2 to 5 mm and a length of 20 to 20 mm.
It was cut in a direction perpendicular to the casting direction so that 60 countries were formed. When this strip was put into water, it became spiral-shaped as shown in FIG. 2 as it absorbed water, and when it was stirred, it gradually curled into a spiral shape as shown in FIG. 6.

The results are shown in Table @1.

Comparative Example 2 A single-layer sheet was prepared and cut in the same manner as in Example 1, except that the mixture was cast on a glass plate without using the stretched polyvinyl alcohol film. Even when the obtained strips were put into water, they only swelled and no curling was observed.

The results are also shown in Table 1.

Table 1 (Note) The volume after water absorption is the apparent volume when the dry strip toy is placed in water and squeezed strongly after it has been soaked in water, and the weight after immersion and squeezing is the weight at that time.

The time it takes for the sample to return to its original dry weight when opened during drying at 40°C, spread the sample after immersion and squeezing into a 10a square glass container, and leave it in a room at 40'C.

Example 2 A laminated sheet was prepared in the same manner as in Example 1 except that peat moss 20 (1) with a moisture content of 15% was further blended in Example 1.
This sheet was cut in a direction perpendicular to the casting direction to have a medium size of 2 to 5N1 and a length of 20 to 605+. When this strip was put into water, it curled into a spiral shape as it absorbed water. The volume after water absorption is 605 squares, and the weight after soaking and drawing is 6
The drying time at 4.5 f and 40° C. was 12.5 hours.

Example 6 The water-containing particles consisting of 600 parts of monomethyl maleate-modified polyvinyl alcohol particles used in Example 1 and 210 parts of water were fed into an extruder having a diameter of 601 WII, and 1o.

While kneading at ~145°C and discharging from the T-die,
The biaxially oriented polyvinyl alcohol film used in Example 1 was extrusion coated to a thickness of 0.5 fl. 14 pieces of this laminate
The material was heat-treated in a dryer at 0° C. for 1.5 hours to impart high water absorption properties, and then passed through a steam bath to soften it. .

The thus obtained laminated sheet has a medium size of 2 to 6 cm and a length of 10σ.
I cut it diagonally so that it would fit. When this strip was put into water, it curled into a spiral shape as shown in Figure 6 as it absorbed water. Volume after water absorption is 200 mark, weight after immersion and squeezing Vi+ 50.51 When drying at 40℃ 5
It took 4.5 hours.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the laminate of the present invention, and FIGS. 2 and 6 are sketches showing an example of the shape of the cut product of the laminate of the present invention when placed in water. . A... Thin layer base material B... Super absorbent polymer patent applicant Nippon Gosei Chemical Industry Co., Ltd.

Claims (1)

[Claims] 1. A super absorbent laminate consisting of a thin layer base material) and a super absorbent polymer +jp10S). The laminate according to claim 1, wherein 2.0) is a super absorbent polymer layer containing an inorganic or organic material. 5. The laminate according to claim 1, wherein (4) is a film. 4. (A) 81 Footwear according to claim 1, which is a di-polyvinyl alcohol film. 5. The laminate according to claim 1, which has the shape of a cut product.