KR19990070515A - Manufacturing Method of Adhesive Using Sodium Silicate - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method for producing an adhesive using sodium silicate.

2. The technical problem to be solved by the invention

SUMMARY OF THE INVENTION The present invention solves the problems associated with conventionally using sodium silicate alone as an adhesive, by using sodium silicate as a main material and adding a tacky organic compound having excellent compatibility with it in an appropriate proportion. In addition, the object of the present invention is to provide a method for producing an adhesive using sodium silicate, which has excellent flexibility and prevents phase separation during long-term storage, thereby greatly improving storage.

3. Summary of Solution to Invention

The present invention for achieving the above object provides a method for producing an adhesive using sodium silicate of stirring by mixing 78 to 82 parts by weight of sodium silicate and 18 to 22 parts by weight of ethylene vinyl acetate emulsion.

4. Important uses of the invention

It has a use as an adhesive agent, such as papers of this invention.

Description

Manufacturing Method of Adhesive Using Sodium Silicate

The present invention relates to a method for producing an adhesive using sodium silicate, and more particularly, to a method for producing an adhesive using sodium silicate added by adding ethylenevinyl acetate emulsion to sodium silicate.

Sodium silicate, also called water glass, is a type of silicate compound that exists in nature in various forms, ranging from Na ₂ O · 3.75SiO ₂ to 2Na ₂ O · SiO ₂ , and is generally a method of melting sodium carbonate and quartz powder. It is a white odorless substance obtained by the back.

Sodium silicate as described above has inherent adhesive power and has been widely used as a binder for papers and castings in the past, and in particular, it is inexpensive to produce compared to other organic adhesives, and does not cause pollution during manufacturing or after manufacturing. Has the advantage of.

However, when using sodium silicate alone as an adhesive, it has a disadvantage in that the water resistance is weak when exposed to moisture or moisture in the air. It is easy to bend when bent (면) has a characteristic that represents a big problem in terms of flexibility.

As described above, in order to solve the problem when using sodium silicate alone as an adhesive, a method of improving physical properties such as flexibility and water resistance by mixing a tacky organic compound with sodium silicate has been considered. Since the tacky organic compound does not exhibit hydrophilicity, when the adhesive is prepared by mixing it with water-soluble sodium silicate, it is very difficult to select a solvent for diluting it.

That is, when an inorganic solvent such as water is used, it is difficult to dissolve the tacky organic compound, and when an organic solvent such as benzene is used, dissolution of sodium silicate is difficult.

In addition, when stored for a long time in a state in which sodium silicate is mixed with a viscous organic compound, the added viscous organic compound exhibits phase separation with sodium silicate, which results in difficulty in uniform mixing during dissolution mixing at the work site. Has a big disadvantage.

As such, when the sodium silicate and the tacky organic compound are not mixed in a uniform state, the adhesive layer is easily chopped because the adhesive layer may not exhibit a desirable effect in terms of flexibility, and ultimately, a desired adhesive force may not be obtained.

In connection with the above-mentioned problems, Japanese Patent Laid-Open No. 61-252395 and Japanese Patent Laid-Open No. 5-32931 produce a strength strengthening agent or a coating agent by mixing a tacky organic compound such as water-soluble polyvinyl alcohol with sodium silicate. Introducing the technology.

The polyvinyl alcohol used as a tacky organic compound in the above technique has a hydroxyl group as a hydrophilic group in the molecule and shows excellent water solubility, so that water can be used as a solvent even when mixed with sodium silicate. The pressure-sensitive adhesive composition also has a problem in that it is difficult to homogeneously mix when dissolving and mixing due to serious phase separation when stored for about one week or more. Other sticky organic compounds that do not exhibit water solubility are not mentioned.

As described above, the present invention is to solve various problems that occur when conventionally using sodium silicate alone as an adhesive. By using sodium silicate as a main material and adding a tacky organic compound having excellent compatibility therewith in an appropriate ratio, It is an object of the present invention to provide a method for preparing an adhesive using sodium silicate, which has excellent water solubility, water resistance, and flexibility, as well as prevents phase separation during long-term storage, thereby greatly improving storage.

In order to achieve the above object, the present invention provides a method for producing an adhesive using sodium silicate in a method of mixing and stirring 78 to 82 parts by weight of sodium silicate and 18 to 22 parts by weight of ethylene vinyl acetate emulsion.

As described above, the sodium silicate used as the main material in the present invention exists in various forms according to the molar ratio of Na ₂ O and SiO ₂ constituting the molecule, but among them, Na ₂ O: SiO ₂ is 1 Sodium silicate, consisting of a molar ratio of 3.2 to 3.4, is commonly used, which has a specific gravity at 20 ° C of 1,260 or higher, insoluble in water of 0.2% or less, and Na ₂ It has a component composition corresponding to four kinds of sodium silicate including O 6 to 7% and SiO ₂ 23 to 25%.

Ethylene vinyl acetate emulsion mixed with the above-mentioned sodium silicate is an elastomer used as a material added as an adhesion improving agent, and has excellent water resistance and weather resistance, and can be used as an adhesive of various materials such as paper, wood, glass, metal, and silicic acid. It is excellent in compatibility with soda and can be easily dissolved and mixed using water as a solvent even after two weeks or more have elapsed in a state of mixing with sodium silicate.

In addition, since the ethylene vinyl acetate emulsion exhibits ductility upon curing, when used in combination with the sodium silicate, the ethylene vinyl acetate emulsion may exhibit a remarkable improvement effect on many problems in terms of water resistance and flexibility when using sodium silicate alone.

As the mixing amount of the ethylene vinyl acetate emulsion is increased, the above-mentioned improvement effect can be further increased. However, when the mixing ratio of 78 to 82 wt% of sodium silicate exceeds 22 wt%, the ethylene vinyl acetate emulsion may be mixed. Due to the relatively high price, it is a rising factor of the overall manufacturing cost, so there is a problem in that the economic advantages of using relatively low-cost sodium silicate cannot be sufficiently taken into consideration. Since the improvement effect mentioned above is hard to be obtained, it is preferable to mix in the range of 18-22 weight%.

The above-mentioned sodium silicate and ethylene vinyl acetate emulsions are mixed in an appropriate mixing ratio range as described above, and then, by adding an appropriate amount of water as a solvent, the mixture is stirred at an appropriate speed of a conventional method at room temperature (preferably 20 to 30 ° C). When mixed, the adhesive of the present invention can be produced.

Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples, and Experimental Examples.

<Example 1>

An adhesive was prepared by adding 8 kg of sodium silicate, 2 kg of ethylene vinyl acetate emulsion, and an appropriate amount of water, which were prescribed in Korean Industrial Standard KS M 1415, to a calibrated mixer and stirring and mixing at 25 ± 5 ° C. for 35 minutes.

<Example 2>

In the same manner as in Example 1, the mixing amount of sodium silicate was 8.2 kg and the addition amount of ethylene vinyl acetate emulsion was 1.8 kg.

<Example 3>

In the same manner as in Example 1, the mixing amount of sodium silicate was 7.8 kg and the addition amount of ethylene vinyl acetate emulsion was 2.2 kg.

Comparative Example

In the same manner as in Example 1, 9 kg of sodium silicate and 1 kg of polyvinyl alcohol were added instead of ethylene vinyl acetate emulsion as a tacky organic compound.

Experimental Example

Water resistance test

Each of the adhesives prepared in Examples 1 to 3 and Comparative Examples were mixed with a pulp material to produce a paper particle board having a size of butterfly × length × thickness of 50 × 200 × 10 mm. The particle board was impregnated with water at 30 ° C. for 3 hours, and then dried at 20 ° C. for 10 minutes to prepare a test piece.

Each of the test pieces prepared above was loaded using a UTM (model UEH-200A) tester manufactured by Japan S with a three-point loading method (span length: 150 mm) with an average strain rate of about 10 mm / min. The maximum load was measured and the bending strength was measured by substituting this in Equation 1, and the results are shown in Table 1 below.

In Equation 1,

P: Maximum load (N)

L: Span (cm)

b: butterfly of test piece (cm)

t: thickness of test piece (cm)

Test piece Example 1 Example 2 Example 3 Comparative example Bending Strength (N / cm ² ) 0.86 0.72 1.0 Adhesive layer separation

As can be seen from the results shown in Table 1, in Examples 1 to 3 according to the present invention, there was a slight difference in bending strength as the mixing ratio of ethylene vinyl acetate mixed with sodium silicate was changed. On the other hand, the overall bending strength of 0.86 to 1.0 N / cm ^{2 was shown} , whereas in the comparative example using only sodium silicate as the adhesive, separation of the adhesive layer occurred and thus strength measurement itself was impossible.

Storage Experience

As in the water resistance test example, the adhesive prepared in Examples 1 to 3 and Comparative Example was placed in each storage container, and then allowed to stand for 1 week, 2 weeks, and 3 weeks, respectively, and then observed delamination in the adhesive composition. As a result, the adhesive of Examples 1 to 3 of the present invention exhibited a slight gelation phenomenon after 2 weeks, and after standing for 3 weeks, a layer separation phenomenon that could be visually confirmed in the lower layer of the storage container was found, but was stirred. In this case, it could be observed that the above-mentioned layer separation phenomenon was removed by mixing evenly.

On the other hand, in the comparative example, a considerable amount of gel layer was formed in the lower part of the reservoir after two weeks, and was not uniformly mixed even when stirred.

As described above, the present invention not only solves the problems in terms of water resistance and flexibility when using sodium silicate alone by mixing ethylene vinyl acetate emulsion at an appropriate ratio using sodium silicate as a main material, but also for a long time. It is a useful invention that can prevent the separation of the sodium silicate and the tacky organic compound during storage and ultimately improve the utilization efficiency of sodium silicate as an adhesive.

Claims (1)

78 to 82 parts by weight of sodium silicate and 18 to 22 parts by weight of an ethylene vinyl acetate emulsion are mixed and stirred.