JPH0819637B2 - Water disintegratable moisture-proof paper - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-proof paper, and more particularly to a moisture-proof moisture-proof paper.

[0002]

BACKGROUND ART Tarpaulin paper and wax paper have long been known as moisture-proof paper, but in recent years, so-called polylaminated paper coated with a polymer film has been widely used. As the polymer film formed in this case, a vinylidene chloride, SBR, and a polyolefin film such as polyethylene are known.

On the other hand, in recent years, the recycling of waste paper has become an important issue from the viewpoint of resource saving, pollution prevention and global environmental protection. However, all of the above moisture-proof papers are not sufficiently reusable because they do not have sufficient disintegration property, and when they are incinerated, they produce black smoke or the combustion heat becomes too large. There were drawbacks such as damage to the incinerator.

[0004] to overcome the shortcomings of, while maintaining the moisture waterproof performance, a method of manufacturing a wastepaper recovery also easy moisture waterproof paper, i.e., blanking Tajien unit mainly 1,4 bonds in the polymer chain of methyl methacrylate - Bed Tajie <br/> emissions based interpolymer aqueous emulsion by blending the Watsukusu system Emarujiyon solids 5-200 parts by weight of polymer relative to the synthetic rubber latexes solids 100 parts by weight as essential components Is applied onto the surface of the base paper by a conventional method and dried at a melting point of the wax or at a temperature higher than the wax, and a method for producing a moisture-proof and waterproof paper for easily recovering waste paper is proposed (Japanese Patent Publication No. 55-22597).

[0005]

The moisture-proof and waterproof paper produced by this method is an excellent one that can be recovered as waste paper, but it is still not sufficient in terms of moisture-proof and waterproof property, and especially wrapping paper. In the case of using as a material, there is a drawback in that a high sealing temperature of about 130 ° C. is required for the heat sealing property which is a new requirement recently.

The inventors of the present invention have conducted extensive studies to solve the above-mentioned drawbacks, and as a result, styrene having a copolymerization ratio of at least a certain range on the surface of kraft paper or high-quality paper. .Applying a coating solution containing a (meth) acrylic acid copolymer emulsion and a wax emulsion
When a more water disintegratable polymer film membrane is provided, it is possible to improve moisture and water resistance more than before.
Together, excellent heat-sealing properties Ruue, times as waste paper
The inventors have found that a moisture-proof paper having a water disintegratable property that can be stored can be obtained, and arrived at the present invention.

Accordingly, an object of the present invention is to provide a moisture-proof moisture-proof paper which is excellent not only in moisture-proofing and waterproofing properties but also in heat-sealing property and which can be recovered as waste paper.

[0008]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
At least styrene and (meth) acrylic on the surface of the paper
Styrene with an acid copolymerization ratio of 10:90 to 60:40
An emulsion of a (meth) acrylic acid copolymer and a wax having a melting point of 140 ° C. or less was prepared by adding 1 to the solid content of the copolymer.
30 to 60 parts by weight of wax as solid content with respect to 00 parts by weight
The coating solution for the additional inclusion so that the parts coated and dried, was achieved by the water defibration properties moistureproof paper which is characterized by comprising providing a MizuHanare disintegrable film layer on the surface of the paper.

The paper used in the present invention is kraft paper.
Alternatively, it is preferable to use high-quality paper. Those skilled in the art are familiar with these craft or fine papers.

The styrene / (meth) acrylic acid copolymer used in the present invention has a copolymerization ratio of styrene: (meth) acrylic acid = 10: 90 from the viewpoint of water disaggregation and moisture resistance.
-60: 40. The moisture-proof property can be adjusted by adding a wax emulsion described later, and therefore the particularly preferable range of the copolymerization ratio is 30:70 to 5.
It is 0:50.

From the viewpoint of film formability, the molecular weight of the styrene / (meth) acrylic acid copolymer is 300,000-12.
Is preferably 00,000, particularly 500,000 to 1,000,000 der
Rukoto is preferable.

Styrene which can be used in the present invention
Examples of (meth) acrylic acid copolymers include Newcoat S-1380, 1300, 1260 and 12
40 (both are trade names of Shin-Nakamura Chemical Co., Ltd.), Boncoat 5450 and Boncoat U-48 (both are trade names of Dainippon Ink and Chemicals, Inc.) and the like.

The wax emulsion that can be used in the present invention can be appropriately selected from known wax emulsions such as paraffin wax emulsions and polyethylene wax emulsions having a melting point of 140 ° C. or lower, but particularly, A paraffin wax emulsion is preferable because it has a large water repellency, is suitable for adjusting the moisture permeability, and is inexpensive.

The amount of the wax emulsion used is preferably 30 to 60 parts by weight in terms of solid content based on 100 parts by weight of solid content of the styrene / (meth) acrylic acid copolymer. If the amount is less than 30 parts by weight, the effect of adjusting the water vapor transmission rate of the moisture-proof paper as the final product cannot be obtained by adding the wax emulsion. On the other hand, when the amount is more than 60 parts by weight, the film forming property of the film film provided on the surface of the moisture-proof paper is deteriorated.

The coating liquid containing the styrene / (meth) acrylic acid copolymer and the wax emulsion in the present invention can be appropriately adjusted by a known method, but from the viewpoint of economy and working environment, etc. The emulsion of the copolymer and the emulsion of the wax are separately prepared according to a known method, and then, the solid content ratio of the copolymer and the wax is 30 to 60 with respect to 100 parts by weight of the former. It is preferable to mix them so that the weight of the mixture is about 1 part.

In the present invention, a water-soluble binder such as polyolefin, PVA, casein, etc., a thickener, a strengthening agent, a water retention agent, an antifoaming agent and the like are appropriately added to the above coating liquid, if necessary. be able to. These additives are preferably added so as to have a coating amount of 0.5 g to ² g / m ^2, and in particular, PVA having a degree of polymerization of 500 to 1800 is added to 100 parts by weight of the copolymer. It is preferable to add 0.5 to 50 parts by weight.

From the viewpoint of imparting moisture resistance, the coating amount of the above coating liquid on paper is preferably 5 to 25 g / m ² after drying, and particularly preferably 10 to ²⁰ g / m ² . Also, from the viewpoint of sufficient heat sealability, 1
It is preferable that the ^{0g / m 2 ~20g / m 2} . The drying temperature is not particularly limited, but it is preferable to set it to a temperature equal to or higher than the melting point of the wax used.
Generally, drying at 70 ° C to 160 ° C is sufficient.

In the present invention, the moisture-proof coating layer may be applied on both sides of the base paper, or on the surface of the base paper opposite to the moisture-proof coating layer for the purpose of preventing slippage and curling. The back coat layer may be formed using a known material such as PVA or colloidal silica containing an anti-slip agent.

As described above, the moisture-proof coating layer formed on the surface of the base paper has the incompatible wax dispersed in the resin film and the resin is water disintegratable , so that the moisture-proof coating of the present invention can be obtained. The disintegration property is extremely good when the paper is collected and processed as waste paper.

Further, the water permeability can be controlled by the amount of wax added, and since the resin is water degradable , the water permeability can also be controlled by the coating thickness, and the moisture permeability can be controlled by the polyethylene laminate. It is easy to make it equivalent to paper.

Further, while heat resistance is higher than that of polyethylene laminated paper, heat sealability of about 80 ° C. is sufficient,
The moisture-proof paper of the present invention can also be heat-sealed into a bag or cup,

Furthermore, the chemicals used are FDA (FOOD AND
DRUG ADMINISTRATION) Since it can be easily selected from the chemicals that use approved substances, it can be used as a packaging material for foods, and it disappears due to the action of water and light in the natural environment, making it a source of pollution. I won't.

[0023]

As described above in detail, according to the present invention, although it can be recovered and reused as waste paper, it is sufficiently moisture-proof and has a good heat-sealing property. Can be greatly expanded. Especially F
Not only can it be made suitable as a food packaging material by using chemicals that use DA-approved substances, but it can also be used for practically unrecoverable uses such as dynamite wrapping paper, etc. It can also contribute to prevention of occurrence.

[0024]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

[0025]

Example 1 Nucoat S-1300 (trade name of styrene-acrylic milk-white emulsion manufactured by Shin-Nakamura Chemical Co., Ltd.) in which the solid content is 100 parts by weight and the melting point is 6
Purnit 101Z as 0 ° C paraffin wax
The (milky white emulsion) (trade name of Shin-Nakamura Chemical Co., Ltd.) is weighed out so that the solid content is 50 parts by weight, and mixed according to a conventional method so that the viscosity at 25 ° C. is 50 Cp to 100 Cp.
The coating liquid was adjusted so that

The coating liquid thus obtained was applied to Kraft paper of 75 g / m ^{2 with} a Meyer bar and dried at 120 ° C. for 40 seconds.
The coating amount was 12.4 g / m ² after drying. The moisture-proof paper obtained as described above was subjected to a moisture permeability test according to JIS Z0208, and as a result, after 4 hours, 44.0 g /
m ² .

Then, using a small household mixer (internal capacity 1.2 liters, rotation speed 11,000 rpm), the moisture-proof paper obtained in this example was added to tap water at room temperature to give a pulp concentration of 1% by weight. %, And agitated for 3 minutes, almost no suspended matter was observed. This demonstrates that the moisture-proof paper of the present invention has excellent disintegration properties and is suitable for being recovered and recycled as waste paper.

If a press pressure of 0.5 kg / cm ² is applied using a sealer manufactured by Toyo Tester Co., Ltd.,
When the heating conditions for complete sealing were examined, it was 80 ° C.
It required heating for 2 seconds.

[0029]

Example 2 The coating amount of Example 1 was changed from 12.4 g to 14.2 g.
A moisture-proof paper was prepared in the same manner as in Example 1 except that The moisture vapor permeability of the obtained moisture-proof paper is 37.8 after 24 hours.
It was g / m ² , and the disaggregation was exactly the same as in Example 1 and was good.

From these results, it was proved that the moisture permeability can be adjusted by changing the coating amount without adversely affecting the disintegration property. Further, heating for complete sealing required 2 seconds at 80 ° C. as in the case of Example 1.

[0031]

Example 3 Newcoat S-13 used in Example 1
In the same manner as in Example 1 except that Newcoat S-3300 (styrene-acrylic emulsion manufactured by Shin-Nakamura Chemical Co., Ltd.) was used instead of 00, and the coating amount after drying was 14.1 g / m ^2. A moisture-proof paper was prepared. With respect to the obtained moisture-proof paper, the moisture vapor transmission rate and the disintegration property were evaluated in the same manner as in Example 1. The moisture vapor transmission rate after 24 hours was 37.7 g / m ^2.
And the disaggregation was good. Also, heating for a complete seal required 80 ° C. for 2 seconds.

[0032]

[Example 4] As a paraffin wax, pull knit 1
Paraffin wax 32 with a melting point of 60 ° C. instead of 01Z
And parts by weight, vinyl acetate content of 28% ethylene - using paraffin wax emulsion containing a vinyl copolymer 8 parts by weight of acetic acid, the coating amount after drying 13.5 g / m
^With respect to the moisture-proof paper produced in exactly the same manner as in Example 3 except that 2, the moisture permeability and disintegration property were evaluated in the same manner. The water vapor transmission rate after 24 hours was 57.7 g / m ² , and the disaggregation was good. Heating at 80 ° C. for 1 second was sufficient for complete sealing.

[0033]

Example 5 Newcoat S-33 used in Example 4
Example 4 was repeated except that Newcoat S-1240 (styrene-acrylic emulsion manufactured by Shin-Nakamura Chemical Co., Ltd.) was used instead of 00. The coating amount after drying was 15.7 g / m ² .

The moisture-proof paper thus obtained had a water vapor transmission rate of 62.2 g / m ² after 24 hours and had good disintegration property. or,
Heating at 80 ° C. for 1 second was sufficient for complete sealing.

[0035]

Comparative Example 1 With respect to a commercially available polykraft paper laminated with polyethylene, the moisture permeability and the disintegration property were measured in the same manner as in Example 1. The water vapor transmission rate is 16.
In the case of polykraft paper laminated with 0 μm polyethylene (ratio 1-1), 35.7 g / m ² , 20.1 μm
Polycraft paper laminated with polyethylene (compared to 1
It was 26.6 g / m ² in -2), but it was confirmed by the disaggregation test that suspended matter was observed and the disaggregation was poor.

Further, when a sealer manufactured by Toyo Tester Co., Ltd. was used and the complete sealing condition was examined at a press pressure of 0.5 kg / cm ² , heating at 130 ° C. for 4 seconds was required.

[0037]

Example 6 was prepared except that using high-quality paper of 82.4 g / m ² instead of kraft paper 75 g / m ² in the same manner as in Example 1 moistureproof paper used in Example 1, the When the performance was evaluated, the moisture vapor transmission rate after 24 hours was 39.0 g /
m ² was even better than that of Example 1, and the disintegration property and heat sealability were the same as those of Example 1.

[0038]

Comparative Example 2 Various performance evaluations were carried out in the same manner as in Example 1 for a commercial product having a coating layer composed of a methyl methacrylate / butadiene copolymer and paraffin wax, which corresponds to the product of JP-B-55-22597. Where I went,
The dispersibility was good, but the water vapor permeability after 24 hours was 128.0 g / m ² and the amount of heat required for complete sealing was 130 ° C. for 4 seconds, both of which are inferior to the moisture-proof paper of the present invention. It was confirmed.

[0039]

Example 7 Instead of using 100 parts by weight of Newcoat S-1300, 90 parts by weight of Newcoat S-1300 in solid content and polyvinyl alcohol (PVA105:
A moisture-proof paper was produced in the same manner as in Example 1 except that 10 parts by weight of Kuraray Co., Ltd.) was used, and the moisture permeability was measured. The moisture permeability after 24 hours was 38.3 g / m ^2. The moisture permeability was further improved as compared with the case of Example 1.

[0040]

[Embodiment 8] The results of the following crease test of the moisture-proof papers of Examples 2, 3, 5 and Comparative Example 2 are shown in Table 1. Folding test: The sample moisture-proof paper was folded in a cross shape from the front and then hung once with a 2 kg covering roller, then folded back from the back side and hung once again with the covering roller to make a creaseed sample. Was produced. From each of the obtained samples, sampled centering on the cross part of the cross,
The moisture permeability after 24 hours was measured.

[0041]

[Table 1]

As is clear from the results shown in Table 1, the moisture-proof paper obtained by the present invention was found to be significantly stronger against creases than the conventional products. The results of the above Examples and Comparative Examples are summarized in Table 2.

[0043]

[Table 2]

[0044]

[0045]

[0046]

Claims (2)

[Claims] 1. At least styrene is provided on the surface of the paper.
The copolymerization ratio of (meth) acrylic acid is 10:90 to 60:
Styrene (meth) acrylic acid copolymer of 40, and a melting point of 140 ° C. or less of the wax emulsion, the co
The solid content of wax is 100 parts by weight of the solid content of the polymer.
In a coating solution for the additional inclusion so that 30 to 60 parts by weight coated and dried, the water defibration properties moistureproof paper which is characterized by comprising providing a MizuHanare disintegrable film layer on the surface of the paper. 2. The coating solution further has a polymerization degree of 500 to 1,
The water disintegratable moisture-proof paper according to claim 1, wherein 1.5 to 50 parts by weight of 800 polyvinyl alcohol is contained.