JPH03229761A - Snow composition - Google Patents

Abstract

PURPOSE:To obtain a snow composition having a freely controllable quality and suited for skiing by mixing natural snow, artificial snow or icy snow with a particulate highly water-absorptive resin. CONSTITUTION:100 pts.wt. snow selected from among natural snow, artificial snow made on an artificial snow making machine and icy snow made by finely dividing lumps of ice is mixed with 0.1-10.0 pts.wt. highly water-absorptive particulate resin having a particle diameter of 20-500mum before absorption of water. The resin is desirably one having a water absorptivity of 30-500 times for ion-exchanged water, and a polyacrylate obtained by reversed phase suspension polymerization in an organic solvent, a vinyl alcohol/acrylate copolymer or a saponified isobutylene/maleic anhydride copolymer is desirable. By the above mixing, a snow composition having a freely controllable quality and suited for skiing can be obtained.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to snow compositions.

More specifically, the present invention relates to freely controlling the snow quality and obtaining a snow composition suitable for skiing by mixing granular superabsorbent resin with natural snow, artificial snow, or ice and snow.

[Prior art] (Natural snow) In recent years, snowfall has been decreasing year by year, which is causing problems for ovens at ski resorts. Moreover, the natural snow that accumulates on the ground is too soft and difficult to ski on, making it unsuitable for ski slopes as it is, so the snow has to be compacted many times with snow compactors. Also, compacting snow using a snow compactor is not suitable for competitions.
Methods such as ``tsuboashi'', where people step on the ground with only their shoes on, and methods of sprinkling water on a layer of snow, have been adopted. The ski slopes created in this way are greatly affected by the outside temperature, and the quality of the snow changes over time. This is because sublimation and condensation occur inside the snowpack, and the snow crystals change, progressing from "plum snow" to "rough snow." Rough snow is extremely difficult for skiers to slip on, and therefore, the work of breaking up the snow, that is, blooming, must be performed frequently, but even this cannot be said to be sufficiently effective.

(Artificial Snow) Artificial snow machines have recently been increasingly introduced at ski resorts in the country in order to hasten or extend the skiing season. There are two types of artificial snowmaking devices: gun type and fan type. The method for making snow using these devices is to use adiabatic expansion of compressed air with high-pressure water in the atmosphere below 0°C, or use cold air to make fine ice. The artificial snow made in this way contains more than 10% water and has a density of 0.3 to 0.4 g/cm3.
The strength is less than I kg/c2, and it is not suitable for skiing unless the snow is compacted. Also, compared to natural snow, the quality of snow changes rapidly, and after a few days, the outer diameter decreases by about 1.
In some cases, it may progress to ~5mm of coarse snow. As mentioned above, rough snow is a troublesome snow quality for skiing, and the same countermeasures as mentioned above are taken.

In addition, in the case of artificial snow made by mixing a water-swellable material (water-absorbing resin) with water and freezing it with an aerator, as disclosed in Patent Application Publication No. 1983-50052Ei, the density of the snow The strength varies easily depending on aeration conditions and freezing conditions, and the density is 0.4 to 0.9 g/cm3, and the strength is 10 to several 100 kg/C2. Such snow is more like rough, fine ice or ice burn than snow. Therefore, when making artificial snow using only water-swellable materials, in order to make it suitable for skiing, it is necessary to add a surfactant or adjust the particle size and water absorption ratio so that the frozen particles do not bond together more than necessary. or blooming frequently. Such snow can be said to be extremely difficult to use at ski resorts.

[Problems to be Solved by the Invention] Various kinds of snow such as natural snow and artificial snow have the following problems.

■If the snow is not compacted, the slope will not be suitable for skiing.

■ Snow of arbitrary density and strength cannot be obtained. In other words,
It is not easy to create snow that suits the skier's level and preferences.

■Snow quality changes significantly over time, making it difficult to maintain the condition of the slopes.

■In early spring, the snow becomes rough, making the slopes unsuitable for skiing.

[Means for Solving the Problem] As a result of intensive research to solve the conventional problems, the present inventors have found that by mixing super absorbent resin granules with snow, snow of arbitrary density and strength can be produced. In addition, a snow composition has been obtained which suppresses changes in snow quality over time and allows easy and inexpensive production and maintenance of ski slopes that are preferred by skiers.

According to the present invention, 100 parts by weight of snow selected from natural snow, artificial snow made by an artificial snow-making device, and snow made by crushing ice blocks into fine powder, and a particle size of 20 to 500 μm before water absorption are used.
Provided is a snow composition characterized by comprising a mixture with 0.1 to 10.0 parts by weight of super absorbent resin granules of m.

The superabsorbent resin particles used in the present invention are commercially available starch-polyacrylates, polyacrylates obtained by reverse-phase suspension polymerization in an organic solvent, and polyacrylic acids obtained by stationary aqueous solution polymerization. Examples include saponified copolymers of salt, vinyl alcohol and acrylate copolymers, and isobutylene and maleic anhydride copolymers, but especially spherical polyacrylics obtained by reverse-phase suspension polymerization in organic solvents. Preferred are acid salts, saponified copolymers of vinyl alcohol and acrylic acid salts, or copolymers of imbutylene and maleic anhydride.

The reasons why spherical superabsorbent resin granules are preferable are that they are easy to mix uniformly with snow, and that after freezing, the "ice bridges" between the particles are finely and evenly dispersed, so they do not become too hard.
One example is that even when exposed to the surface layer of snow, it does not make slipping worse because it is granular.

Further, the super absorbent resin granules of the present invention preferably have a particle size of 0.05 mm to 2II11 after absorbing water, in order to mix uniformly with snow.
0μ- is suitable. If it is less than 20 μm, it is too fine and it is difficult to mix uniformly with the snow, and if it is more than 500 μm, it will be scattered in the snow, which is undesirable.

The super absorbent resin granules used in the present invention have a water absorption capacity of 30 to 500 times, preferably 50 to 2 times, relative to ion-exchanged water.
00 times better. If the water absorption capacity is less than 30 times, a large amount is required for snow, which is not economical. If it is larger than 500 times, the gel strength will be weak when water is absorbed, and it will be easily broken when pressure is applied, which is not preferable. Furthermore, it is preferable that when water is absorbed, the material does not become pasty but remains granular and exhibits fluidity. When it becomes paste-like, it freezes into one large block of ice and cannot be used as a ski slope unless it is crushed into small pieces. To avoid this, there is a method of atomizing the snow before freezing, but it is highly viscous and requires a large amount of power, so it is not an economical method for improving snow quality. In order to maintain fluidity in granular form even after absorbing water, it is possible to increase the degree of crosslinking with polyvalent epoxy or polyvalent amine, but excessive crosslinking will reduce the water absorption capacity, so Adjust the amount of crosslinking agent.

For example, the following method can be used to mix the superabsorbent resin granules of the present invention and snow.

■5 to 100 particles of super absorbent resin of the present invention are added in advance.
After absorbing twice as much water, mix it evenly with the snow.

(2) The superabsorbent resin granules of the present invention are uniformly mixed with snow without being made to absorb water in advance.

The method (2) of mixing after water absorption is mainly used to obtain snow of arbitrary density and strength. For 100 parts by weight of snow,
Take 0.1 to 10.0 parts by weight of super absorbent resin granules (unabsorbed), absorb 5 to 100 times the water so that the water-swollen material after water absorption does not exceed 200 parts by weight, and mix uniformly with the following. .

The mixed snow composition freezes due to the latent heat of the snow and the outside air, but at that time, water seeps out from inside the water-swollen body,
Microscopic observation of thin sections confirmed that water freezes on the surface of the material, creating an "ice bridge" with the surrounding snow.

Therefore, to obtain snow of arbitrary density and strength, "ice bridge" is required.
All you have to do is adjust the amount of water supplied from within the water-swollen body. In other words, by arbitrarily changing the parameters such as the particle size of the superabsorbent resin granules, the ratio of water absorption capacity/water absorption capacity, and the amount of water-swollen bodies, the amount of water supplied from the water-swelled bodies can be controlled. You can get snow with density and strength. For example, if you want to obtain hard and heavy snow quality, the particle size should be small (20 to 150 μm).
The ratio of water absorption capacity/water absorption capacity is large (30 to 80%), and the amount of water-swollen material is large (30 to 200 parts by weight). On the other hand, if you want to get soft and light snow, use large grain size (150-500
μ11), water absorption capacity/water absorption capacity ratio is small (10-50%)
The amount of water-swollen material may be reduced (10 to 80 parts by weight). In addition, these water-swellable bodies have a lower water absorption capacity than the superabsorbent resin granules, so they absorb liquid water generated due to increases in outside temperature and maintain the desired snow quality so that it does not change. be able to.

The method (3) of mixing without water absorption is mainly used to suppress deterioration of snow quality. 0.1 to 10.0 parts by weight of super absorbent resin granules (unabsorbed) are mixed with 1.0 parts by weight of snow. Generally, snow that has just been created by an artificial snow-making device is a mixture of about 60-90% ice particles and about 40-10% liquid water, and this kind of wet snow is difficult for beginners and intermediate skiers to use. It is difficult to slip.

For such snow, when superabsorbent resin granules are mixed, it absorbs unfrozen water and improves the wet snow condition to a dry one, making the slope popular with beginners and intermediate skiers. .

Also, in early winter and early spring, when the outside temperature rises and water (liquid phase) is generated by melting snow, if super absorbent resin granules are mixed in, the deterioration of snow quality can be suppressed.

The ratio of super absorbent resin granules to 100 parts by weight of snow is 0.
．． 1 to 10.0 parts by weight, but for particularly wet snow, increase the mixing ratio (1.0 to 10.0 parts by weight), and for slightly damp snow, use 0.1 to 1.0 parts by weight. Preferably, the addition of 50% is preferred.

The method of mixing superabsorbent resin granules and snow is to place unabsorbed superabsorbent resin granules or water-swollen materials that have previously absorbed water to a predetermined water absorption capacity in a container equipped with a device for supplying the material to the bottom of the container. There is a method in which the container is loaded into a vehicle for ski slope maintenance, and the material is mixed in parallel with ski slope maintenance while being sprayed from a supply device. This method can be used with natural snow, artificial snow, or frozen snow.

Another method is to attach a device that directly sprays super-absorbent resin granules using compressed air to an artificial snow-making device such as a gun type or fan type, so that the super-absorbent resin granules are spread simultaneously while making artificial snow. There is a method of scattering and mixing.

Yet another method is to mix superabsorbent resin granules that have been air-transported with water to absorb water in an artificial snowmaking device, and then disperse the water-swollen material into the atmosphere using compressed air. At this time, since the artificial snow making device is simultaneously making artificial snow, it can be mixed.

[Example] Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

In addition, the water absorption capacity, fluidity, density and strength of the snow composition after freezing in the following Examples and Comparative Examples are determined by the following operations.

(Water absorption capacity for ion-exchanged water) Disperse 0.5 g of dry polymer in 11 ion-exchanged water,
After being allowed to stand for 24 hours, the water-swelled weight (W) of the resulting polymer was measured by filtration through a 60-mesh wire mesh, and this value was divided by the initial dry polymer weight (W).

(Fluidity after water absorption) After 50 cc of ion-exchanged water was added to 1.0 g of dry polymer and the water was completely absorbed, the water-swollen body was observed without moving, and the fluidity was expressed as 01×1△.

(Density of snow composition after freezing) Take out snow whose volume is known, weigh it, and divide the weight by the volume. The unit is g/C113°.When the snow is soft, insert a thin stainless steel box with a known internal volume into the snow to remove the snow with a known volume. In case of hard snow,
Cut the snow into squares with a saw, measure the dimensions with a ruler, and calculate the volume.

(Strength of snow composition after freezing) A weight is dropped onto the snow composition using a Kinoshita hardness meter, and the falling strength is measured. The unit is kg/c. Replace the adapter so that the 2° disc sinks into the snow composition at a distance of 7 to 30 m.
Find the strength from the conversion table.

Example 1 (Type of super absorbent resin granules) Super absorbent resin granules absorb 50 times as much water to make a water-swollen body, and the weight ratio of the super absorbent resin granules to ice and snow (16 mesh) made by crushing ice is 33. : 100 and frozen at -5°C.

After 16 hours had passed after mixing, the density and strength of the snow composition were measured and shown in Table 1.

In general, the strength at which a skier can easily slide is about 1.0 kg/cm2 for beginners, and as he progresses to harder snow, it is about 10 kg/cm2 for Olympic-level skiers.
Hard snow of about 12 is required. However, snow that is harder than that is disliked by both amateur and professional skiers, and the probability of injury in the event of a fall is extremely high.

Example 2 (Particle size of super absorbent resin granules) A snow composition was prepared in the same manner as in Example 1 except for changing the particle size of the super absorbent resin granules, and the density and strength were measured. -2.

Example 3 (Water absorption capacity of super absorbent resin granules) A snow composition was prepared in the same manner as in Example 1 except for changing the water absorption capacity of the super absorbent resin granules, and the density and strength were measured.
It is shown in Table-3.

Example 4 (Ratio of water-swollen material) A snow composition was prepared in the same manner as in Example 1, except that the weight ratio of water-swollen material and ice and snow was changed, and the density and strength were measured.
4.

Example 5 (Slope skiing test) (Teine Ski Resort) A slope with a width of 3 slopes, a length of 15 cm, and a depth of 15 cm was installed, and the slope was covered with 10 natural snow.
Water-swelled body 3 made by absorbing 0 parts by weight and BL-151 50 times as much water
Spread a uniform mixture of 3 parts by weight on the ski slope, -
After being left for 14 hours at an outside temperature of 5 to 12 degrees Celsius, the density and strength of the snow composition and the glide properties of the ski were examined. The results are shown in Table-5.

Example 6 (Unabsorbed super absorbent resin granules) Unabsorbed super absorbent resin granules were mixed with Ice M (16 mesh pass) made by crushing ice, and stored at -1°C to determine density and strength. The changes over time were measured. Table 6 shows the results.
Shown below.

[Effect of the invention] The snow composition of the invention has arbitrary density and strength,
We provide ski slopes according to the level and preferences of skiers. It also has the effect of suppressing changes in snow quality over time, helping to maintain the condition of the slopes. In particular, it exhibits an effective suppressing effect against changes to "rough snow" due to changes in outside temperature and rapid changes in snow quality in artificial snow made with artificial snowmaking equipment, and maintains ski slopes suitable for skiing for a long period of time. I can do it.

Claims (5)

[Claims] (1) 10 pieces of snow selected from natural snow, artificial snow made using artificial snowmaking equipment, and ice and snow made by crushing ice blocks into fine powder.
1. A snow composition comprising a mixture of 0 parts by weight and 0.1 to 10.0 parts by weight of super absorbent resin particles having a particle size of 20 to 500 μm before water absorption. (2) The snow composition according to claim 1, wherein the superabsorbent resin granules have a water absorption capacity of 30 to 500 times as much as ion-exchanged water. (3) The snow composition according to claim (1), wherein the super absorbent resin granules are a saponified product of polyacrylate, a copolymer of vinyl alcohol and acrylate, or a copolymer of isobutylene and maleic anhydride. . (4) The snow composition according to claim 1, wherein the superabsorbent resin granules have previously absorbed 5 to 100 times more water. (5) The snow composition according to claim (1), wherein the superabsorbent resin granules are not pre-absorbed with water. (6) The snow composition according to claim (1), wherein the superabsorbent resin granules are spherical.