JPH0249517A - Artificial sphagnum moss - Google Patents

Abstract

PURPOSE:To provide an artificial sphagnum moss outstanding in water resistance, water retentivity, appearance, hand touch and water absorption rate, comprising a foam derivative produced by sulfonation of a PS foam to its interior. CONSTITUTION:A PS foam is made to react, using e.g., fuming sulfuric acid, pref. at 95-100 deg.C for 72-240hr to effect sulfonation to its interior. The resultant PS foam derivative (its salt, if needed) is the main constituent of the objective artificial sphagnum moss.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to artificial sphagnum moss, and its purpose is to provide an artificial sphagnum moss that has excellent water absorption, water retention, appearance, and feel. .

[Conventional technology]

Demand for natural sphagnum moss, which has traditionally been used in general households, industrial applications, and agriculture, has increased recently, and domestic production alone cannot keep up with the demand. It is strongly requested from all quarters.

However, since it is a naturally occurring product, its supply is limited.

Under these circumstances, various types of artificial sphagnum moss have been developed recently.
Although it is commercially available, sphagnum moss is required to have a good balance of bulk, water absorption, water retention, and air permeability. More desirably, it is also required to have a high water absorption rate and excellent tactility.

The characteristics of this sphagnum moss will be further explained below using potted sphagnum moss as an example.

The basic performance required for potted plants is not only excellent water absorption and water retention, but also uniformity of moisture content and air permeability between the upper and lower layers of the pot, especially for potted plants. Air permeability in the lower layer is extremely important.

When watering from the top of the pot, the water flows down from the top layer to the bottom layer, so normally the upper layer of the pot holds less water, and the lower layer holds more water. Therefore, a material with a high water retention ratio is desirable.

Furthermore, ventilation is required in the lower layer, and even if the water retention difference between the upper and lower layers is small, if the ventilation is insufficient, oxygen supply to the roots will be inhibited, which will have a negative impact on the plants.

At this time, if the air permeability is low, a shortage of oxygen will occur.

Conventional artificial sphagnum moss is mainly prepared from crosslinked products of hydrophilic and water-insoluble polymers such as polyethylene oxide, sodium polyacrylate, and polyvinyl alcohol.

Such conventional artificial sphagnum moss has insufficient water absorption and water retention properties, and its appearance and feel are also unsatisfactory. In addition, it is difficult to say that its water absorption rate is particularly high.

[Problem to be solved by the invention]

The problem to be solved by the present invention is to solve each of the drawbacks of the conventional artificial sphagnum moss mentioned above, and more specifically, it has excellent properties in terms of water absorption, water retention, air permeability, appearance, and water absorption rate. The goal is to develop sphagnum moss that has the following properties.

[Means to solve the problem]

This problem can be solved by sulfonating polystyrene foam with at least one of fuming sulfuric acid, chloro or fluorosulfonic acid, and sulfur trioxide (SO8), and using the resulting product as a salt as sphagnum moss. .

That is, the present invention relates to an artificial sphagnum moss which is mainly composed of sulfonated polystyrene foam, which is actively sulfonated to the inside with a sulfonating agent and further converted into salt if necessary.

[Structure and operation of the invention]

The artificial sphagnum moss of the present invention is characterized by the following two points. That is, (1) the polystyrene foam is actively sulfonated to the inside of the foam with at least one of the above-mentioned sulfonating agents, and (2) the polystyrene foam is further treated with an organic salt or an inorganic salt as necessary.

It has not been known to date that polystyrene foam can be sulfonated by treating it with at least one of fuming sulfuric acid, chloro or fluorosulfonic acid, and sulfur dioxide as described above, and it has been known that sulfonation can be carried out by treating polystyrene foam with at least one of fuming sulfuric acid, chloro or fluorosulfonic acid, and sulfur dioxide. It is only known that polystyrene foams with sulfonated surfaces can be used as soil conditioners. Originally, polystyrene foam is a foam consisting of almost closed pores, and it is a common belief in this type of industry that even if this foam is sulfonated, only the surface thereof will be sulfonated.

However, according to the research of the present inventor, when polystyrene foam was actively sulfonated to the inside with a sulfonating agent, it was surprisingly possible to sulfonate the polystyrene foam without damaging its individual cell structure in any way. It has been found that polystyrene foam can be sulfonated to the inside, and it has also been found that polystyrene foam that has been sulfonated to the inside has significantly superior properties as a sphagnum moss, compared to one that is sulfonated only on the surface.

It has also been discovered that even when the sulfonated polystyrene foam is converted into a salt, it exhibits almost the same properties as the sulfonated polystyrene foam, and the present invention was completed based on these new facts.

The polystyrene used in the present invention may be a homopolymer or a copolymer with butadiene, acrylonitrile, etc., but the effects of the present invention are more likely to be exhibited as the polystyrene content is higher.

The ratio of styrene to other monomers in the above copolymer is usually 40 mol% or less, preferably 10
It is about 20 mol%. There are no particular limitations on the form of the copolymer, including block copolymerization, graft copolymerization, and other random copolymerization.

In the present invention, it is essential to use foamed polystyrene. Various polystyrene foams can be used as long as they are foamed, and it is particularly preferable to use the polystyrene foam itself, and it is preferable to avoid pulverized polystyrene foams. Polystyrene foam can be used in packaging materials that are cheap and easily available, such as cushioning materials such as sheets, ribbons, and lumps, as well as molded objects such as plates for insulation, cases, objects, containers, etc. It is also possible to utilize already finished polystyrene foam.

In the present invention, it is the polystyrene foam that is subjected to the sulfonation treatment, and even if the styrene monomer is subjected to the treatment and then polymerized (including copolymerization), the intended purpose will not be achieved. Further, even if polystyrene is sulfonated and then foamed, a sufficient foam cannot be obtained. For example, polymerized sodium styrene sulfonate is water-soluble.

In particular, since the present invention uses polystyrene foam, conventional waste materials that have been used as insulation and cushioning materials can also be used, which is significant in that it has developed a new use for waste materials.

The fuming sulfuric acid used in the present invention is 20 to 30% oleum, and a commercially available product can be used as is.

Although chlorosulfonic acid is commonly used, fluorosulfonic acid can also be used. Although liquid sulfur dioxide is used as sulfur trioxide, it is also possible to react in a gaseous state. Conditions for the reaction between the polystyrene foam and these acids are such that the inside of the foam can be positively sulfonated.

There is no particular limitation as long as the inside can be sulfonated, but
For example, usually 90-100°C, preferably 95-1
When the reaction is carried out for about 3 to 8 hours at 00°C, and for more than 72 hours, preferably for about 72 to 240 hours at room temperature, the sulfur content of the product will be 16 to 21 for any sulfonating agent.
% and reach a sulfonated range almost to the inside.

The polystyrene foam treated with the sulfonating agent is washed with water until sulfate ions are no longer detected, neutralized as necessary to form a salt, dried according to a conventional method, and further adjusted to an appropriate size and shape as necessary for production. This is the invention of sphagnum moss.

The method of neutralizing to form a salt is not limited in any way, and may be carried out according to a conventional method. The neutralizing agent in this case is usually an alkali, and the alkali used for neutralization is preferably a common alkali or alkaline earth metal hydroxide, or ammonia or an alkyl amine, such as an organic amine such as ethanolamine. used.

The sulfonated polystyrene foam or its salt according to the present invention is a solid having a cell structure like the raw material polystyrene foam. For example, reference Fig. 1 shows micrographs (magnification: 10
0 times).

However, Reference Figure 1 (A) shows the raw material, Figure 1 (B) shows the foam of the present invention, and the polystyrene foam in Reference Figure 1 (A) is "Asback" manufactured by Asahi Kasei ■. Reference Figure 2 also means the same thing; Figure (A) is a commercially available bead-shaped polystyrene foam, and Figure (B) is a sulfonated product up to the inside thereof.

As is clear from these Reference Figures 1 and 2, there is almost no change in the cell structure in any case, and it is clearly revealed that the cell structure is sulfonated to the inside while maintaining the original cell structure.

Furthermore, the sulfonated polystyrene foam and its salts of the present invention are hydrophilic but water-insoluble.

In addition, while the raw material polystyrene foam is hydrophobic, sulfonated polystyrene foam or its salt (hereinafter simply referred to as sulfonated polystyrene foam) is hydrophilic, and the cell structure that makes up the foam is hydrophilic. Because it itself is hydrophilic, it can quickly absorb and retain water, and its water absorption amount reaches about 20 to 80 times its own weight. As described above, the sulfonated polystyrene foam of the present invention has a high water absorption capacity, has a cellular structure, and easily releases the absorbed water, so the sulfonated polystyrene foam according to the present invention has excellent water retention properties, and the absorbed and retained water can be easily used by plants. This leads to

- For boat fishing, it is said that it is preferable that sphagnum moss has good adsorption and retention of plant nutrients such as nitrogen (ammonia), potassium, magnesium, calcium, manganese, iron, copper, and zinc. On the other hand, the sulfonated polystyrene foam according to the present invention has a large cation exchange capacity of 4.5 to 6 milligram equivalents/g and has a cell structure that can easily and quickly absorb water. It enters the water, undergoes ion exchange, and is retained by adsorption. Furthermore, since cation exchange is performed by sulfonic acid groups, the adsorbed and retained nutrients are not easily leached out and are fully utilized. As described above, the sulfonated polystyrene foam according to the present invention has a significantly improved ability to retain these nutrients.

In addition, when the sphagnum moss of the present invention absorbs water, it has a volume of 2.5 to 2.5% of its dry volume.
Because it expands to about three times its size, there are many voids even though it retains sufficient moisture, and the amount of air created by these voids increases, resulting in good breathability even though there is sufficient moisture. Become.

In the present invention, this polystyrene foam is used to make sphagnum moss, but the shape of the sphagnum moss is not particularly limited. For example, specifically, the shape is a thin string, a small piece, a sheet, a ring, a tube, a granule, a powder, etc., and a thin string is particularly preferable. It may also be in granular form, and it is also possible to use it by crushing polystyrene foam.

〔Effect of the invention〕

In principle, a wide variety of sulfonated polystyrene foams can be used as the sulfonated polystyrene foam according to the present invention, regardless of the shape of the raw material polystyrene foam. In particular, scraps or cut ends of polystyrene foam discharged from factories can be used as raw materials, so they can be produced at a very low cost and are extremely meaningful industrially.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples.

Example 1 String polystyrene foam (
Asahi Kasei ■ "Aspac") 3g and 25% oleum 50
IIIl! and shake it so that the surface of the polystyrene gets wet with the fuming sulfuric acid. Next, a condenser was attached to the flask, outside air was shut off, and the reaction was allowed to take place in a boiling water bath for 8 hours. Unreacted fuming sulfuric acid is collected and the reactant is poured into water. After filtration, the washing solution was washed with water until no sulfate ions were observed, and then dried at 105°C to a constant weight, and the S content was 20.0.
% sulfonated polystyrene foam was obtained.

It is clear from the S content that the inside is sulfonated. This can be used as is as sphagnum moss.

Figure 3 shows the relationship between the reaction time and the S content of the obtained sulfonated polystyrene foam.The sulfonation reaches a certain value after several hours of reaction, and that value is the same as that of the polystyrene foam. This clearly shows that all phenyl nuclei are substituted with at least one sulfonic acid group. However, the quantification of sulfur was carried out according to a method in which the sample was melted in an alkali with anhydrous sodium carbonate and sodium peroxide, and the sulfur was precipitated as barium sulfate.

Example 2 5I! In an Erlenmeyer flask, add 20 g of S-shaped polystyrene foam (Asahi Kasei's "Aspac") and 50 g of 25% oleum.
0g and shut off outside air. The reaction was allowed to proceed at room temperature for 7 days while shaking the polystyrene to wet the surface.

Thereafter, the same operations as in Example 1 are carried out, starting from the recovery of unreacted fuming sulfuric acid. 35.9 g of sulfonated polystyrene foam with an S content of 17.8% was obtained.

FIG. 4 shows the relationship between S content and reaction time in the case of sulfonation at room temperature. The foam thus obtained can be used as is as sphagnum moss.

Example 3 3.0 g of string polystyrene foam (Asahi Kasei's "Aspac") and 501 dl of chlorosulfonic acid were placed in a 200 rtll flask, a cooler was attached, and outside air was shut off.
The reaction was carried out in a boiling water bath for 8 hours. After the reaction, the chlorosulfonic acid is recovered and the reactant is placed in water.

The reaction product is washed with warm water at about 60°C until the washing solution becomes neutral, and dried at 100-110°C to a constant weight. 4.84 g of sulfonated polystyrene foam with S content of 16.4%
I got it. This can be used as is as sphagnum moss.

Example 4 2.2 g of commercially available bead-shaped polystyrene foam and 10.9 g of sulfur trioxide (303) were placed in a 500 mR Erlenmeyer flask, the outside air was shut off, and the flask was allowed to react at room temperature for 10 days. After the reaction, the reactants are poured into water. After washing with water until sulfate ions are no longer detected in the washing solution, it is dried at 105°C to a constant weight. 4.64 g of sulfonated polystyrene foam with an S content of 20.6% was obtained. This can be used as is as sphagnum moss.

Example 5 A column with a diameter of 50 mm and a length of 150 mm was filled with 3 g of string-like polystyrene foam (Asahi Kasei's "Aspa Soku"), one end of the column was filled with an aspirator, and the other end was filled with 30 g of sulfur trioxide.
Connect it to the flask containing the. Then, the pressure inside the column was slightly reduced using an aspirator, and sulfur trioxide was introduced into the column and brought into contact with the polystyrene foam to carry out a sulfonation reaction for 7 days. The operations after the reaction were carried out in the same manner as in Example 4. 6.1 g of sulfonated polystyrene foam with an S content of 19.38% was obtained. This can be used as is as sphagnum moss.

Example 6 2 g of sulfonated polystyrene foam obtained in Example 2
2% calcium chloride (CaCβ22H20) aqueous solution 2
00 ml, left overnight, filtered, washed with water, and dried at 105°C to obtain 2.2 g of calcium salt with a Ca content of 9.47%. This was ground into particles with a particle size of 4 to 10 mesh to obtain sphagnum moss.

Examples 7 to 10 In Example 6 above, aqueous solutions of caustic soda, caustic potash, magnesium chloride, and ammonia were used in place of the aqueous calcium chloride solution, and all other treatments were carried out in the same manner.

The properties of the sphagnum moss obtained in Examples 1 to 10 were measured. The results are shown in Table 1. S by gravimetric method
The fact that the S content is always slightly higher than the S content determined by titration indicates that crosslinking by sulfones occurs in addition to free sulfonic acids.

1) The values measured by gravimetric method as BaSO4 are shown.

2) Free sulfonic acid groups are reduced to 0. Titrate with INNaOH,
The value calculated from the consumption amount is shown.

3) Cation exchange capacity: Powder sphagnum moss, take 1 g of it, fill it in a column with an inner diameter of 15 mm and a length of 250 mm.
% anhydrous sodium sulfate solution and drain the effluent to 0.0%. Titration was performed with IN specified NaOH, and the cation exchange capacity was determined from the amount consumed.

However, when the sphagnum moss is a salt, the free sulfonic acid was converted to free sulfonic acid with hydrochloric acid, and then the same procedure as described above was performed to obtain the free sulfonic acid.

4) Sphagnum moss was soaked in water overnight, filtered, and its weight was measured using the following formula.

5) The volume when dry and when water is absorbed was measured and calculated from the following formula.

Example 11 (Measurement of cation adsorption amount) Each of the sphagnum moss of Examples 2 and 6 was powdered, and 1 g was powdered with an inner diameter of 15
Fill a column with a length of 250 mm x 250 mm, flow a solution containing the cation to be measured, measure the amount of cations contained in the flowing water, and subtract the amount of cations that flowed out from the amount of cations added at the beginning. It was taken as the adsorption amount of cations. The adsorption amounts of various cations are shown in Table 2.

Table 2 Example I2 1 g of sphagnum moss was immersed in water, and the amount of water absorbed after a predetermined immersion time was measured. However, the amount of water absorbed at the immersion time of O minutes was measured as follows. That is, place a fine wire mesh on top of the funnel, weigh out 1 g of sphagnum moss on the wire mesh, and pour 100 g of purified water on top.
td was poured, and the amount of water absorbed immediately after that was measured. The relationship between immersion time and water absorption amount is shown in Figure 3. As is clear from FIG. 3, the sphagnum moss of the present invention made of expanded polystyrene sulfonic acid or its salt has a faster water absorption rate than natural sphagnum moss or artificial sphagnum moss, and instantly reaches its full water absorption capacity. It turns out that it absorbs water.

However, in FIG. 3, (1) is of Example 1, (2) is of Example 9,
(3) represents natural sphagnum moss, and (4) represents commercially available artificial sphagnum moss.

Example I3 1 g of sphagnum moss is soaked in water to absorb sufficient water, and excess water is removed by filtration. This was transferred to a 10 (1+fi) beaker and left in a 30℃ constant temperature box, and after being kept in a constant state, the amount of retained water remaining without evaporation of the sphagnum moss was measured. The amount of water retained after a certain period of incubation was expressed as a ratio, expressed as a percentage of retained water, and calculated using the following formula.

The relationship between the standing time and the retained water rate is shown in Figure 4.

However, in Figure 4, (1) is from Example 4, (2) is from Example 2, (3) is natural sphagnum moss, (4) is natural mountain moss, and (5) is natural sphagnum moss.
) indicates commercially available artificial sphagnum moss.

Example 14 Sphagnum moss is often used as soil when replanting pothos, which is an ornamental plant. Therefore, replanting was performed using the sphagnum moss of Example 6 of the present invention. At the same time, we also replanted the plants using sphagnum moss and compared them. The pothos I used was about 20cm tall.
The size of the pot is 18 cm in diameter and 20 cm in height.
It was CI11. The pothos plants replanted using sphagnum moss in Example 6 showed good growth, similar to the pothos plants using sphagnum moss.

Example 15 When cultivating plants in pots, spreading sphagnum moss on the surface of the soil prevents the soil from drying out or becoming hard, and sphagnum moss is often used for this purpose. Therefore, from the time when Satsuki was replanted in mid-May, the sphagnum moss of Example 6 of the present invention was spread on the surface of the soil, and the growth and degree of dryness of the soil were observed. It tended to lag behind moss.

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 and 2 are graphs showing the relationship between sulfur content and reaction time when polystyrene foam is sulfonated. Further, FIG. 3 is a graph showing the relationship between the amount of water absorbed by various types of sphagnum moss and time, and FIG. 4 is a graph showing the relationship between the amount of retained water and time. (The above) Patent applicant: Asahi Chemical Industry Co., Ltd. Sakoda Chemical Development Laboratory Co., Ltd. Reaction/Time-opening (Time-opening) No.? Figure anti-cancer/wait open (Sunday) '/5 stone time n (now) 20rr^ 1λO Tokikawa

Claims (1)

[Claims] (1) An artificial sphagnum moss characterized by comprising as a main component a polystyrene foam derivative obtained by sulfonating the inside of the polystyrene foam and further converting it into a salt if necessary.