JPH08116803A - Flame-retardant mulching material - Google Patents

Abstract

PURPOSE: To obtain a hardly ignitable mulching material prevented from a fire, retaining its flame retardancy even after subjected to rainfall etc., by curing a silicate on the surface of the bark fibers of broadleaf tree etc., with a curing agent followed by incorporation of an aqueous emulsion resin. CONSTITUTION: A silicate on the surface of the bark fibers of broadleaf and/or coniferous tree (pref. water-glass) is cured with a curing agent (pref. a phosphoric acid solution) followed by incorporation of an aqueous emulsion resin (pref. an acrylic emulsion resin), to obtain the objective mulching material. The respective amounts of the components to be used are pref. as follows: 100 pts.wt. of the ground bark, 0.1-20 pts.wt. of the silicate, 0.1-20 pts.wt. of the curing agent, and 0.1-30 pts.wt. of the aqueous resin emulsion.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flame-retardant mulching material. More specifically, it relates to a flame-retardant mulching material used for greening projects and agriculture.

[0002]

2. Description of the Related Art It is common to lay mulching material between roots of trees that have been planted and between trees in order to suppress evaporation of water from the ground surface and to prevent weeds from growing. Is. It has been proposed that this mulching material be mixed with vegetation paste in order to prevent the mulching material from scattering and being washed away after being spread (Japanese Patent Laid-Open No. 06-133652).

[0003]

However, in the conventional mulching materials, regardless of whether vegetation paste is mixed or not, a fire is often caused by throwing tobacco, etc.,
It is desired to develop a mulching material that prevents fires caused by these types of fires and does not easily ignite. Further, the conventional flame-retardant mulching material has a drawback that the flame-retardant effect lasts for a relatively short time because the flame-retardant agent is gradually washed away when it receives rainfall after construction. Therefore, a flame-retardant mulching material having a flame-retardant effect for a long time is desired.

[0004]

Means for Solving the Problems As a result of intensive studies to solve this problem, the present inventors have mixed a silicate with a conventional mulching material, and after coating the fiber surface with a curing agent, After curing, this is used as a flame retardant and mixed with an aqueous emulsion resin as a vegetation paste that exerts adhesiveness when the water content adhering to the fiber surface escapes. The inventors of the present invention have found that the problem of fire occurrence can be solved without the fuel agent being washed away, and have reached the present invention.

That is, the present invention relates to a flame-retardant mulching material obtained by incorporating an aqueous emulsion resin into the bark of a hardwood and / or a softwood, the surface of which has been hardened with a curing agent using a silicate.

The present invention will be described in detail below. The bark used in the present invention may be either a broad-leaved tree and / or a coniferous tree. Also, these pieces of wood may be used. In the present invention, a silicate cured with a curing agent is used. As the silicate, water glass (sodium silicate), potassium silicate, ammonium silicate or the like is used.

As the curing agent for the silicate, a phosphoric acid solution or a mineral acid such as sulfuric acid or hydrochloric acid, a silica fluoride such as sodium silicofluoride or potassium silicofluoride, carbon dioxide, glyoxal or trioxane can be used. A phosphoric acid solution is preferable because of its low cost, safety, and its effect.

A material obtained by curing a silicate with a curing agent serves as a flame retardant. However, the flame retardant of the present invention is preferably manufactured inexpensively from its application, and relatively inexpensive water glass (sodium silicate) is suitable. The water glass may be any of No. 1, 2 and 3. The flame retardant effect is further enhanced by uniformly dispersing the added silicate and curing agent on the fiber surface.

The addition amount of silicate as a flame retardant and curing agent is 0.1 to 20 with respect to 100 parts by weight of ground bark.
A weight part (solid content) is desirable, and if less than 0.1 part by weight, the flame retardant effect cannot be exhibited, which is not preferable. Moreover, even if the amount added exceeds 20 parts by weight, the flame retardant effect is not further improved, which is uneconomical.

The aqueous emulsion resin as a vegetation paste is one or two of acrylic emulsion resin, urethane emulsion resin, acetic acid emulsion resin, vinyl chloride emulsion resin, vinylidene chloride emulsion resin and styrene-butadiene emulsion resin. A mixture of one or more kinds is used, but an acrylic emulsion resin is preferably used from the viewpoint of compatibility with a flame retardant, economy, and the like.

The acrylic emulsion resin as the vegetation paste used in the present invention is usually produced by the following method. It can be obtained by emulsion polymerization of a monomer mixture containing a vinyl monomer containing styrene and / or methyl methacrylate as a main component and a crosslinkable monomer. Further, a functional monomer is used together with the monomer mixture for imparting the stability of the emulsion. In addition, a surfactant as an emulsifier, a polymerization initiator and the like are used.

The amount of the acrylic emulsion resin thus produced, which is used as a vegetation paste, is preferably 0.1 to 30 parts by weight (solid content) with respect to 100 parts by weight of pulverized bark. More preferably, 0.3 to 20 parts by weight is suitable. If the addition amount is less than 0.1 parts by weight, the moldability of the mulching material is not sufficient and the scattering prevention effect cannot be exhibited. Further, if it exceeds 30 parts by weight, the molding effect is not further improved, which is uneconomical. The addition of the acrylic emulsion resin as the vegetation paste to the hardwood and / or coniferous bark is preferably diluted several times to several tens of times so as to facilitate uniform mixing.

Next, an example of the method for producing the flame-retardant mulching material of the present invention will be described. That is, hardwood and / or coniferous bark crushed using a conventional crusher, for example, a chopper-type crusher, put a certain amount in a conventional mixer, for example a ribbon mixer, add silicate to it, After applying it evenly to the bark, add a curing agent and mix well to cure. Then, an aqueous emulsion resin as a vegetation paste is added to the mixture, and the mixture is uniformly mixed.

The effect of the vegetation paste is expressed by the fact that when mulching material is laid and then pressure is applied from the upper surface, the moisture adhering to the fiber surface moves to the lower layer and the water content on the surface decreases, and the adhesive strength of the aqueous emulsion is reduced. Is supposed to appear.

However, the inventors of the present invention have found through various experiments and observations that the flame-retardant mechanism of the flame-retardant mulching material to which the flame-retardant agent of the present invention is added is that the silicate and the curing agent (phosphoric acid solution) are in a combustion atmosphere. It is presumed that the non-combustible coating coats the wood fibers with the generated polyphosphoric acid and prevents the ignition, by being heated by the heat. In addition, it is presumed that this is due to the cooling action by evaporation of the structural water in the silicic acid content of the silicate.

As described above, the flame-retardant mulching material containing the silicate, the curing agent and the aqueous emulsion resin suppresses the evaporation of water from the conventional ground surface and prevents the growth of weeds. Effectively, it excels in safety of preventing fire, and its flame retardancy does not decrease even in rainfall. Moreover, it is a flame-retardant mulching material that can be manufactured at low cost.

[0017]

EXAMPLES The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited thereto. Hereinafter, all parts and% refer to parts by weight and% by weight.

The ignition test was carried out by the following method. That is, the mulching material was molded into a 30 cm square with a thickness of 5 cm, left at 30 ° C. for 5 days, and then 5 to 6 m from the diagonal upper part.
With a wind speed of / sec, place the ignited cigarette on the mulching material and observe the combustion state until the cigarette burns.

Example 1 100 parts of crushed bark was charged into a ribbon mixer, 0.5 part of water glass (No. 3 water glass manufactured by Dokai Kagaku) was diluted with 15 parts of water, and then sprayed evenly on the crushed product. And mixed evenly. Next, 0.5 part of a 75% phosphoric acid solution as a hardening agent was diluted with 15 parts of water and then added, and they were mixed sufficiently, and water glass was cured on the surface of the ground fiber. Acrylic emulsion resin (Almatex E-175 manufactured by Mitsui Toatsu Chemicals, Inc. was added to this mixture.
0.5 part of solid content 45%) was diluted with 15 parts of water, and then uniformly sprayed and mixed to obtain a flame-retardant mulching material. The result of the ignition test of the obtained material was good with no evidence of charring or smoking. Further, water was sprayed onto this flame-retardant mulching material at 5 L / min for 24 hours and left at 30 ° C. for 5 days.
As a result of the ignition test, no scorching or smoke was observed and it was good.

Examples 2 to 6 Example 1 was repeated except that the water glass, phosphoric acid solution and aqueous acrylic emulsion resin of Example 1 were changed to the values shown in Table 1.
I went the same way. As a result, no scorching or smoke was observed and it was good. Further, water was sprayed onto this flame-retardant mulching material at 5 L / min for 24 hours and left at 30 ° C. for 5 days.
As a result of the ignition test, no scorching or smoke was observed and it was good.

Example 7 The procedure of Example 1 was repeated, except that the silicate of Example 1 was changed to potassium silicate. As a result, no scorching or smoke was observed and it was good. Water was sprayed onto this flame-retardant mulching material at 5 L / min for 24 hours and left at 30 ° C. for 5 days. As a result of an ignition test, no charring or smoking was observed, and the result was good.

[0022]

[Table 1]

Comparative Example 1 100 parts of crushed bark was charged into a ribbon mixer, 0.5 part of an acrylic resin emulsion (Almatex E-175 manufactured by Mitsui Toatsu Chemicals, Inc.) was diluted with 15 parts of water, and then crushed product. And evenly mixed. As a result of the ignition test of the obtained mulching material, it was ignited and combustion started after about 1 minute.

Comparative Example 2 The procedure of Comparative Example 1 was repeated, except that the acrylic resin emulsion of Comparative Example 1 (ALMATEX E-175 manufactured by Mitsui Toatsu Chemicals Inc.) was changed to 10 parts. As a result of the ignition test of the obtained mulching material, it was ignited and combustion started after about 1 minute.

Comparative Example 3 Example 1 was repeated except that the curing agent was omitted. The result of the ignition test of the obtained mulching material was good without any scorching or smoking. Water was sprayed on this mulching material at 5 L / min for 48 hours and left at 30 ° C. for 5 hours. The result of the ignition test was that ignition started after about 1 minute and combustion started.

[0026]

EFFECTS OF THE INVENTION According to the present invention, a fire is often caused by throwing away cigarettes or the like by mixing vegetation paste, which has not been achieved by the prior art. Therefore, it has been desired to develop a flame-retardant mulching material that does not deteriorate this effect even when it is rained.
The inventors of the present invention were able to achieve the object by coating the fiber surface with a flame retardant containing a silicate and a curing agent, and adding an acrylic emulsion resin as a vegetation paste. That is, the comparative example of the present invention, the result of the ignition test,
The purpose cannot be achieved due to burning and smoke generation. On the other hand, in the examples, not only these objects are achieved, but also the effect of the flame retardant is sustainable because there is no outflow of the flame retardant due to rainfall or the like.

Claims (4)

[Claims] 1. A flame-retardant mulching material obtained by curing a silicate on a bark fiber surface of a hardwood and / or a softwood with a curing agent and then adding an aqueous emulsion resin. 2. The flame-retardant mulching material according to claim 1, wherein the silicate is water glass. 3. The flame-retardant mulching material according to claim 1, wherein the aqueous emulsion resin is an acrylic emulsion resin. 4. A bark comprising 100 parts by weight of ground bark, 0.1 to 20 parts by weight of a silicate, 0.1 to 20 parts by weight of a curing agent, and 0.1 to 30 parts by weight of an aqueous emulsion resin. Flame-retardant mulching material.