JP2003049397A - Moisture proof sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moisture proof sheet having an excellent moisture proofing property and skid-proof capacity, can be recycled after use, suitable for an underlay paper for a tray of a fast food. SOLUTION: This moisture proof sheet is provided with a coating layer including principal desiccating agent and an inorganic pigment on a side of a paper base, and the sheet has <=40 g/m<2> .24 h or water vapor transmission ratio in conformity to JIS Z 0208 and the coating layer includes 25-100 pts.wt. of the inorganic pigment per 100 pts.wt. of the principal desiccating agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-proof sheet having good disaggregation and capable of recovering used paper, and more particularly to a moisture-proof sheet having excellent anti-slip property on the surface of a coated layer, which is suitable for underlayment paper for fast food trays. .

[0002]

2. Description of the Related Art Hitherto, as a moisture-proof sheet for the purpose of preventing moisture, wax paper or the like having a coating layer containing a wax as a main component on the surface of the sheet and having a moisture-proof property has been used. In recent years, laminated paper laminated with a polymer film has come into wide use due to problems of properties and surface slipperiness.

However, such laminated paper has a problem that although it has good moisture resistance, it cannot be re-disintegrated and is discarded as garbage. Due to recent environmental problems in resource saving, it is recovered as waste paper and reused. The development of usable moisture-proof sheets has been required.

For the purpose of improving the above-mentioned problems and further imparting anti-slip properties, there is an invention in which the blending amounts of an acrylic emulsion, a wax emulsion and an inorganic pigment in a coating layer are specified, and JP-A-8-226096. It is disclosed in the official gazette. Furthermore, for the purpose of improving moisture resistance and preventing wax transfer, styrene-acrylic copolymer, rosin,
An invention in which the blending amounts of wax and pigment are limited is disclosed in JP-A-11-12989.

[0005]

However, in the above invention, the anti-slip property is not sufficient when it is used in applications where high anti-slip property is required due to the coating layer of fast food underlayment paper and the like.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a moisture-proof sheet which has good moisture-proof property and anti-slip property and which can collect used paper after use. To provide.

Other objects and effects of the present invention will be easily understood by those skilled in the art by referring to the following description.

[0008]

In order to achieve the above-mentioned object, the moisture-proof sheet of the present invention is provided with a coating layer containing a moisture-proof main agent and an inorganic pigment on one surface of a paper substrate, and J
Water vapor transmission rate according to IS Z 0208 is 40 g / m ² · 24
It is not more than h, and the coating layer contains 25 to 100 parts by weight of the inorganic pigment with respect to 100 parts by weight of the moisture-proof main agent in terms of solid content.

The term "moisture permeability" as used herein refers to the amount of water vapor that permeates a film material having a unit area in a certain period of time when vapor phases having different water vapor pressures are separated by a moisture-proof sheet or the like. The water vapor in the gas phase moves through the moisture-proof sheet from the higher vapor pressure to the lower vapor pressure, diffuses according to the concentration gradient in the moisture-proof sheet, and permeates the moisture-proof sheet.
This phenomenon is called moisture permeability.

The water vapor permeability is measured according to JIS Z 020.
8 and the unit is represented by g / m ² · 24h. The smaller the numerical value of the moisture permeability, the better the moisture resistance of the moisture-proof sheet.

According to this structure, since the moisture permeability is 40 g / m ² · 24 h or less, good moisture resistance comparable to that of conventional laminated paper can be obtained. Further, since the coating layer contains 25 to 100 parts by weight of the inorganic pigment with respect to 100 parts by weight of the moisture-proof base agent in terms of solid content, the conventional moisture-proof sheet such as the underlayment paper for fast food has slip resistance. It can be used for insufficient applications, and in addition, when a roll is made as a raw sheet of a moisture-proof sheet, the coated layer of the moisture-proof sheet can be prevented from transferring to the opposite surface.

In the present invention, the moisture-proof main agent preferably contains an acrylic synthetic resin, a synthetic rubber latex and a wax emulsion.

According to this structure, the use of the acrylic synthetic resin improves the disintegration property, the use of the synthetic rubber latex improves the flexibility and the covering property, and further the wax emulsion. By using, the moisture resistance can be easily adjusted.

In a preferred embodiment of the invention,
In the moisture-proof base agent, the solid content weight ratio of the acrylic synthetic resin and the synthetic rubber latex is 10:90 to 60:
It may be 40.

According to such a constitution, by setting the compounding ratio of the acrylic synthetic resin and the synthetic rubber latex to an appropriate value, it has both better moisture resistance and disintegration property, and moreover, it has a good coating layer. A moisture-proof sheet having flexibility can be provided. In addition, the light resistance and the film forming property of the coated layer are also improved.

In a preferred embodiment of the invention,
In the moisture-proof main agent, the wax emulsion may be blended in the range of 2 to 20 parts by weight in terms of solid content with respect to 100 parts by weight of the mixture of the acrylic synthetic resin and the synthetic rubber latex.

With such a structure, the moisture resistance of the moisture-proof sheet can be further improved by setting the compounding ratio of the wax emulsion to an appropriate value.

In a preferred embodiment of the invention,
The coating layer may be provided in an amount of 10 to 30 g / m ^{2 in} terms of solid content.

In a preferred embodiment of the invention,
The inorganic pigment may be ground calcium carbonate having an average particle size of 5 μm to 50 μm.

According to such a constitution, by setting the average particle diameter of the inorganic pigment within the above-mentioned specific range, the anti-slip property of the moisture-proof sheet becomes better. In addition, by using heavy calcium carbonate with good hydrophilicity as the inorganic pigment,
The film forming property is improved.

In a preferred embodiment of the invention,
The acrylic synthetic resin may be styrene-acrylic synthetic resin.

According to such a constitution, by using styrene-acrylic synthetic resin among acrylic synthetic resins, the light resistance of the coating layer of the moisture-proof sheet and the disaggregation property in water can be further improved. it can.

In a preferred embodiment of the invention,
The synthetic rubber latex may be a styrene-butadiene latex.

According to such a constitution, by using the styrene-butadiene latex among the synthetic rubber latex, the film-forming property of the coating layer of the moisture-proof sheet is improved and the moisture-proof property is improved. You can Also,
When the moisture-proof sheet is folded, flexibility can be imparted to the folded portion so that the coating layer does not crack.

Further, the moisture-proof sheet of the present invention is provided with a coating layer containing an acrylic synthetic resin, a synthetic rubber latex, a wax emulsion and an inorganic pigment on both sides of a paper base material, and one side is coated. Layer coating amount is 1 in terms of solid content
0 g / m ^{2 to} 30 g / m ² , the coating amount of the coating layer on the opposite surface is 1 g / m ^{2 to} 10 g / m ^{2 in} terms of solid content, and the moisture permeability according to JIS Z 0208 is 20 g / m ^2. m
It may be implemented as ² · 24 h or less.

According to such a constitution, by forming the coating layers on both sides of the paper base material, the moistureproof property is improved as compared with the moistureproof sheet coated on one side, and the moistureproof property having better slipperiness and moistureproofness is obtained. A sheet is obtained. Further, by making the coating amount on one surface smaller than the coating amount on the other surface, the coating layer is transferred to the surface opposite to the coating layer surface even when the raw material of the product is wound into a roll shape. Can be prevented.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention will be described in detail below, but the present invention is not limited thereto.

As described above, the moisture-proof sheet according to the present invention is provided with the coating layer containing the moisture-proof main agent and the inorganic pigment on one surface of the paper base material, and has a moisture permeability according to JIS Z 0208. The amount is 40 g / m ² · 24 h or less, and the coating layer contains 25 to 100 parts by weight of the inorganic pigment with respect to 100 parts by weight of the moisture-proof main agent in terms of solid content. With such a structure, the moisture-proof sheet of the present invention can be used as an underlay paper for a fast food tray, an underlay paper for a shoe box, a balance paper for a decorative plate, a wrapping paper for electrophotographic transfer paper cut into an oval, etc. It has slipperiness useful as a base material for applications requiring moisture resistance and moisture resistance.

The moisture-proof sheet according to the present invention is coated with a coating layer comprising an inorganic pigment and a moisture-proof main agent on a paper substrate in order to impart sufficient anti-slip properties even in the above-mentioned applications. It has on at least one surface.

In the present invention, as the inorganic pigment to be added to the coating layer, one kind or two or more kinds can be appropriately selected and used from the general inorganic pigments, but it is preferable to use heavy calcium carbonate. is there. It is more preferably ground calcium carbonate having an average particle size of 5 to 50 μm, and particularly preferably ground calcium carbonate having a particle size of 10 to 30 μm. If the average particle size of the inorganic pigment is less than 5 μm, the wax may transfer from the coating layer to the opposite surface,
On the other hand, when the average particle diameter exceeds 50 μm, it becomes difficult for the coating film of the coating layer to coat the inorganic pigment, and it becomes difficult to set the moisture permeability to 40 g / m ² · 24 h.

The inorganic pigment is preferably added in an amount of 25 to 100 parts by weight, and more preferably 60 to 90 parts by weight, based on 100 parts by weight of the moisture-proof main agent in terms of solid content. If the amount is less than 25 parts by weight, the effect of preventing wax transfer and improving the slip resistance of the coating layer of the moisture-proof sheet is small, and if it exceeds 100 parts by weight, the coating film of the coating layer of the moisture-proof sheet covers the inorganic pigment. Becomes difficult, and sufficient moisture resistance cannot be obtained.

As described above, the coating layer of the moisture-proof sheet according to the present invention contains an inorganic pigment and a moisture-proof main agent,
The moisture-proof main agent is preferably a mixture of an acrylic synthetic resin, a synthetic rubber latex and a wax emulsion. The acrylic synthetic resin, synthetic rubber latex and wax emulsion are preferably used as emulsions dispersed in water.

In the present invention, as the acrylic synthetic resin added to the coating layer, styrene and styrene derivatives,
Acrylic acid and methyl acrylate, ethyl acrylate,
Acrylic copolymers obtained by copolymerizing acrylic acid esters such as butyl acrylate and methacrylic acid esters such as methyl methacrylate, ethyl methacrylate and butyl methacrylate are preferred, and styrene-acrylic synthetic resins are particularly preferred. By adding styrene / acrylic synthetic resin as the acrylic synthetic resin to the coating layer of the moisture-proof sheet, good light resistance can be imparted to the coating layer and disintegration in water can be imparted. Furthermore, when the moisture-proof sheet is used as a wrapping paper, a hot-melt type glue such as ethylene-vinyl acetate may be applied to the binding portion during packaging. By blending acrylic synthetic resin,
The affinity between the moisture-proof sheet and the hot melt type glue is improved.

In the present invention, as the synthetic rubber latex to be added to the coating layer, styrene / butadiene latex, acrylonitrile / butadiene latex,
Methacrylate / butadiene latex is preferable, and styrene / butadiene latex is particularly preferable. Styrene-butadiene latex has a high film-forming property, so even if it is used alone, it can be applied to the coated layer of the moisture-proof sheet with a moisture permeability of 100 g.
Moisture-proof property of / m ² · 24 h or less can be imparted.

The term "high film-forming property" means that the coating film of the coating layer sufficiently covers the inorganic pigment, and a substance having high film-forming property generally has a low glass transition point. Conventionally, when a styrene-butadiene latex having a low glass transition point is used for a coating layer of a moisture-proof sheet, the moisture-proof sheet tends to cause blocking. In the present invention, the blocking of the moisture-proof sheet is prevented by blending 25 to 100 parts by weight of the above-mentioned inorganic pigment having an average particle diameter of 5 to 50 μm with respect to 100 parts by weight of the moisture-proof main agent in terms of solid content. You can

Further, by adding a styrene-butadiene latex, flexibility can be imparted to the coating layer of the moisture-proof sheet. If the coating layer is not flexible, it becomes difficult to coat the inorganic pigment having a large particle size, and the moisture resistance is lowered. Moreover, when the moisture-proof sheet is used as a wrapping paper, the moisture-proof sheet may be folded in accordance with the shape of the object to be packaged. If flexibility is not imparted to the coating layer of the moisture-proof sheet, cracking of the coating layer will occur at the fold when the moisture-proof sheet is folded. When the coating layer is cracked, water vapor passes therethrough, so that the moistureproof property of the moistureproof sheet is deteriorated.

The solid content weight ratio of the acrylic synthetic resin and the synthetic rubber latex is acrylic synthetic resin: synthetic rubber latex = 10: 90 to 60:40, particularly preferably 30:70 to 40:60. Is desirable. Acrylic synthetic resin solid content weight ratio is 10% by weight
When it is below the range, the film-forming property of the coating layer of the moisture-proof sheet becomes too strong, and it becomes difficult to disintegrate in water after collecting the moisture-proof sheet. Furthermore, when a hot-melt type adhesive is applied to the moisture-proof sheet, the affinity between the moisture-proof sheet and the hot-melt type adhesive is deteriorated, and it becomes difficult to apply the glue to the coating layer surface of the moisture-proof sheet. On the other hand, when the distribution ratio of the acrylic synthetic resin exceeds 60% by weight, the film-forming property of the coating layer of the moisture-proof sheet deteriorates, and it becomes difficult to set the moisture permeability to 40 g / m ² · 24 hr or less. Further, the flexibility of the coating layer of the moisture-proof sheet is deteriorated, and when the moisture-proof sheet is folded, cracks of the coating layer are likely to occur at the folded portion, and the moisture-proof property is deteriorated.

In the present invention, the wax-based emulsion to be added to the coating layer includes plant-based waxes such as candelilla wax and carnauba wax, animal-based waxes such as lanolin and derivatives thereof, mineral waxes such as montan wax and ceresin wax. Wax, paraffin wax and derivatives thereof, petroleum wax such as microcrystalline wax, polyethylene wax, montan wax and derivatives thereof, synthetic wax such as microcrystalline wax and derivatives thereof are preferable, and especially polyethylene derivative, rosin and derivatives thereof Carnauba wax and shellac with many functional groups are used together,
It is desirable that the particles are emulsified by mechanically high shear stress without using a surfactant and finished into fine particles that are nearly translucent. Such an emulsified wax has a stable moisture-proof property, and even when the base paper is wound into a roll, the transfer of the wax from the coated layer surface to the opposite surface is reduced.

Further, since this type of wax-based emulsion has heat-sealing properties, when the moisture-proof sheet is used as a wrapping paper, the moisture-proof sheet can be sealed by heat. However, if you want to firmly seal the wrapping paper,
It is desirable to apply hot-melt type glue to the binding portion of the moisture-proof sheet.

The wax-based emulsion is calculated in terms of solid content,
It is desirable that the amount is 2 to 20 parts by weight, particularly preferably 3 to 15 parts by weight, based on 100 parts by weight of the mixture of the acrylic synthetic resin and the synthetic rubber latex. If the blending amount of the wax-based emulsion is less than 2 parts by weight, good moisture resistance of the wax-based emulsion cannot be sufficiently imparted to the moisture-proof sheet. Therefore, keep the moisture permeability at 40 g / m ² · 24 hr or less. Becomes difficult. On the other hand, even if the amount exceeds 20 parts by weight, the effect of increasing the moisture-proof property is the upper limit, and further compounding is disadvantageous in cost. Further, when the base paper of the moisture-proof sheet is manufactured in a roll shape by a paper machine, the wax is transferred from the coating layer of the moisture-proof sheet to the opposite surface by pressure, and the opposite surface of the coating layer becomes slippery.

The moisture-proof main agent and the inorganic pigment to be blended in the moisture-proof sheet of the present invention are kept in balance in their physical properties by specifying the substances and blending ratios specified in the present invention, and a better coefficient of static friction ( It exhibits slipperiness) and moisture permeability (moisture resistance). That is, the inorganic pigment is used to prevent transfer of the wax coating layer surface to the opposite surface,
Anti-slip, blocking, moisture-proof, and the main moisture-proof agent is
By using a mixture of acrylic synthetic resin, synthetic rubber latex and wax emulsion, the acrylic synthetic resin is mainly used for disintegration and hot melt sizing.
The synthetic rubber latex affects the coverage of the inorganic pigment and the flexibility of the moistureproof sheet, and the wax emulsion affects the moistureproofness and heat sealability.

When used as a general wrapping paper, the moisture-proof sheet of the present invention is packed by laminating the coated layer surfaces, the coated layer surface and its opposite surface, and the opposite surface of the coated layer surface depending on the packaging form. Sometimes. If these surfaces are slippery with each other, for example, when articles packed on a pallet are piled up, the cargo tends to collapse during transportation.

In order to prevent the occurrence of the load collapse problem as described above, the moisture-proof sheet of the present invention is provided with the JIS P of the coated layer surfaces, the coated layer surface and its opposite surface, and the opposite surface of the coated layer surface.
The static friction coefficient according to 8147 is preferably in the range of 0.4 to 0.8. If the coefficient of static friction is less than 0.4, the superposed surfaces will be slippery and the load will be easily collapsed. On the other hand, if the coefficient of static friction exceeds 0.8, the superposed surfaces will not slip and the workability of packaging and packing will deteriorate.

Furthermore, since the coating layer of the moisture-proof sheet of the present invention itself has good slip resistance, the coating layer can be provided on both sides of the base paper. The moisture-proof sheet having a coating layer provided on both sides has a coating amount of the coating layer on one side in terms of solid content,
By adjusting the coating amount of the coating layer on the opposite surface to 10 to 30 g / m ² and the solid content of 1 to 10 g / m ² ,
Water vapor transmission rate according to S Z 0208 is 20 g / m ² · 24
It can be h or less. The amount of coating on one side should be small enough to achieve the target of 20g / m ² · 24h, and after coating and drying one side, coating the other side. This is to prevent the phenomenon of blistering called blisters from occurring during drying.

The base paper used as the paper substrate in the present invention can be appropriately selected from unbleached paper, kraft paper, high-quality paper, medium-quality paper, single-glossy paper and the like.

In the present invention, as a method for applying a coating layer to a substrate, a general coating method such as a bar coater, an air knife coater, a blade coater or a curtain coater which is generally used is used. it can. In the case of the present invention, a curtain coater is particularly desirable for forming a uniform thin film.

[0047]

Examples <Example 1> 25.0 parts by weight of emulsion of styrene / acrylic synthetic resin (UC-404: Saiden Chemical Co., Ltd.), styrene / butadiene latex (P-6X20: Japan A & L Co., Ltd.) 25. 0 parts by weight, wax emulsion (WR988: Japan PMC
Inc.) After mixing 10.0 parts by weight to obtain a mixture,
Heavy calcium carbonate (BF200 (average particle size 5.0μ
m): Bihoku Powder Industrial Co., Ltd.) 5 against the above mixture
Dispersing 0% by weight, paper base material (bleached kraft paper: 80 g /
m ² ) was coated on one side so that the solid content was 25 g / m ² to prepare a moisture-proof sheet.

Example 2 Styrene / acrylic synthetic resin emulsion (EK-65: Saiden Chemical Co., Ltd.) 20.0 parts by weight, styrene / butadiene latex (P-6X20: Japan A & L Co., Ltd.) 30.0 Parts by weight, wax emulsion (WR988: Japan PMC
After mixing 10.0 parts by weight, 50% by weight of heavy calcium carbonate (BF300 (average particle diameter 8.0 μm): Bihoku Kouka Co., Ltd.) is dispersed in the mixture to prepare a paper base. On one side of the material (bleached kraft paper: 80 g / m ² ),
The coating was applied so that the solid content was 18 g / m ² .

Example 3 25.0 parts by weight of emulsion of styrene / acrylic synthetic resin (UC-404: Saiden Chemical Co., Ltd.), 25.0 of styrene / butadiene latex (P-6X20: Japan A & L Co., Ltd.) Parts by weight, wax emulsion (WR988: Japan PMC
After mixing 10.0 parts by weight, 50% by weight of heavy calcium carbonate (BF200 (average particle size 5.0 μm): Bihoku Kouka Co., Ltd.) is dispersed in the mixture to prepare a paper base. On one side of the material (bleached kraft paper: 80 g / m ² ),
The coating amount was 15 g / m ^{2 in} terms of solid content and 5 g / m ^{2 on the} opposite surface.

<Comparative Example 1> The coating amount of the coating layer was 5 g / m ^2.
Example 1 was repeated except that

<Comparative Example 2> 2.0 parts by weight of emulsion of styrene / acrylic synthetic resin (UC-404: Saiden Chemical Co., Ltd.), 48.0 of styrene / butadiene latex (P-6X20: Japan A & L Co., Ltd.) The same procedure as in Example 1 was carried out except that the parts by weight were used.

Comparative Example 3 40.0 parts by weight of a styrene / acrylic synthetic resin emulsion (UC-404: Saiden Chemical Co., Ltd.), and a styrene / butadiene latex (P-6X20: Japan A & L Co., Ltd.) ) Was carried out in the same manner as in Example 1 except that the compounding amount of) was 10.0 parts by weight.

<Comparative Example 4> Wax emulsion (W
R988: Japan PMC Co., Ltd.) was carried out in the same manner as in Example 1 except that the compounding amount was 2.0 parts by weight.

<Comparative Example 5> Wax emulsion (W
R988: Japan PMC Co., Ltd.) in an amount of 5.0 parts by weight, except that the amount of heavy calcium carbonate (BF200 (average particle size 5.0 μm): Bihoku Powder Co., Ltd.) was set to 5% by weight. Was carried out in the same manner as in Example 1.

<Comparative Example 6> Wax emulsion (W
R988: Japan PMC Co., Ltd.) in an amount of 13.0 parts by weight, and the amount of heavy calcium carbonate (BF200 (average particle size 5.0 μm): Bihoku Kouka Co., Ltd.) in an amount of 7
Example 1 was repeated except that the amount was 5% by weight.

<Comparative Example 7> In Example 1, the heavy calcium carbonate was mixed with Softon # 2200 (average particle diameter 1.0 μm).
m: Bihoku Flour Milling Co., Ltd.), but the same procedure as in Example 1 was performed.

Comparative Example 8 The procedure of Example 1 was repeated except that the heavy calcium carbonate having an average particle size of 55.0 μm was used.

<Comparative Example 9> In Example 1, the heavy calcium carbonate was replaced with talc (KST-W (average particle size 15.
2 μm): Example 1 except that it was changed to Shokoyama Mining Co., Ltd.
It carried out similarly to.

The moisture-proof sheet thus prepared was evaluated by measuring moisture permeability, coefficient of static friction, blocking property, disintegration property, hot-melt adhesive property (hot-melt adhesive property), and heat-sealing property. In addition, each evaluation method was implemented as follows.

<Moisture Permeability> The moisture permeability test method of the present invention is described in J
It was carried out based on IS Z 0208 Condition B.

<Static friction coefficient> The static friction coefficient is JIS P
According to the 8147 paper and paperboard friction coefficient test method,
It was measured. The static friction coefficient was measured by overlapping the coated layer surface and the coated layer surface, the coated layer surface and the opposite surface, and the opposite surface of the coated layer surface and the opposite surface of the coated layer surface.

<Blocking Property> After coating the base paper with the coating layer, the dried moisture-proof sheet is wound up by the winder section of the coating machine. When unwinding this roll-shaped base paper, ○ when the coating layer and the surface in contact with the coating layer do not adhere, × when adhering
It was determined.

<Disintegration property> A sample of about 20 g (BD) hand-split into about 5 cm square in about 1 liter of tap water was disintegrated with a disintegrator (National MX-V-100, Slidar (made by Tokushu Kika Kogyo)). Use the scale 8 to disintegrate and disintegrate, measure the time until the binding fibers disappear, and disaggregate time 10
If it is within minutes, the disaggregation property is judged to be ○, and conversely the disaggregation time is 10
When it exceeded the minutes, it was judged as x.

<Adhesion of Hot Melt Glue> When an ethylene / vinyl acetate-based hot melt adhesive is applied to the coating layer, when the adhesive can be uniformly applied to the coating layer, ○, conversely When the adhesive was repelled and the adhesive could not be uniformly applied to the coating layer, it was judged as x.

<Heat Sealing Property> The coated layer surfaces are superposed on each other and heat-pressed for about 4 seconds under the conditions of a temperature of 180 ° C. and a pressure of 2.0 kg / cm ² , and when the coated layer surfaces adhere to each other, ○, conversely. When not adhered, it was judged as x.

The moisture-proof sheets obtained in Examples 1 to 3 and Comparative Examples 1 to 9 were measured according to the above-mentioned method, and the moisture permeability, static friction coefficient, blocking property, and Table 1 shows the results of evaluation of disintegration property, hot melt adhesive property, and heat seal property.

[Table 1]

The moisture-proof sheets obtained in Examples 1 to 3 had good results in all the measurement results of moisture permeability, static friction coefficient, blocking property, disintegration property, hot melt adhesive property, and heat sealability. It was However, in the measurement of the heat-sealing property of Example 3, a coating layer is provided on both sides of the moisture-proof sheet, and the coating layer is melted by heat and adheres to the heat-sealing portion. It is not suitable, and sealing with hot melt glue is desirable.

The moisture-proof sheet obtained in Comparative Example 1 was
Since the coating amount of the coating layer was small, the water vapor permeability (moisture resistance) and the heat sealability were deteriorated. The moisture-proof sheet obtained in Comparative Example 2 had a low blending ratio of the acrylic synthetic resin, so that the adhesiveness and disintegration of the hot melt paste were deteriorated. Since the moisture-proof sheet obtained in Comparative Example 3 had a low compounding ratio of the synthetic rubber latex, the moisture permeability (moisture-proof property) was deteriorated. The moisture-proof sheet obtained in Comparative Example 4 was poor in moisture permeability (moisture-proof) and heat-sealing property because the amount of the wax-based emulsion was low. Since the moisture-proof sheet obtained in Comparative Example 5 has a small amount of the inorganic pigment added,
The moisture permeability (moisture resistance), blocking property, and static friction coefficient (anti-slip property) deteriorated, and along with the blocking of the coated layer of the moisture-proof sheet, transfer of the coated layer to the opposite surface occurred. The moisture-proof sheet obtained in Comparative Example 6 contained a large amount of the inorganic pigment, and thus the moisture permeability (moisture-proof property) of the moisture-proof sheet deteriorated.
Since the moisture-proof sheet obtained in Comparative Example 7 has a small particle size of the inorganic pigment, the moisture permeability (moisture-proof property), blocking property, and static friction coefficient (anti-slip property) are deteriorated as in Comparative Example 5, and the moisture-proof sheet With the blocking of the coated layer, there was also a transfer of the coated layer to its opposite side. Since the moisture-proof sheet obtained in Comparative Example 8 has a large particle size of the inorganic pigment,
The moisture permeability (moisture-proof property) deteriorated, and the contact area of the wax-based emulsion having heat-sealing property in the coating layer of the moisture-proof sheet became too small, and the heat-sealing property deteriorated. In the moisture-proof sheet obtained in Comparative Example 9, talc having a tabular structure was used as the inorganic pigment, but the coefficient of static friction (slip resistance) could not be improved.

[0069]

As is clear from the above, the moisture-proof property of the present invention
The sheet is provided with a coating layer containing a moisture-proof main agent and an inorganic pigment,
100 parts by weight of the moisture-proof main agent based on the solid content of the inorganic pigment
25 to 100 parts by weight relative to JIS Z 02
The moisture vapor transmission rate according to 08 is 40 g / m ²・ Being under 24h
By using, it has both good moisture resistance and slip resistance, and is used
It is possible to collect used paper later.

Furthermore, when a mixture of acrylic synthetic resin, synthetic rubber latex and wax emulsion is used as the moisture-proof main agent, a moisture-proof sheet having higher moisture resistance and disaggregation can be obtained.

Claims (9)

[Claims] 1. A coating layer containing a moisture-proof main agent and an inorganic pigment is provided on one surface of a paper substrate, and JIS Z 02 is used.
A moisture-proof sheet having a water vapor transmission rate of not more than 40 g / m ² · 24 h according to 08, and 25 to 100 parts by weight of an inorganic pigment in 100 parts by weight of the moisture-proof base agent in terms of solid content in the coating layer. 2. The moisture-proof sheet according to claim 1, wherein the moisture-proof main agent contains an acrylic synthetic resin, a synthetic rubber latex and a wax emulsion. 3. In the moisture-proof main agent, the solid content weight ratio of the acrylic synthetic resin and the synthetic rubber latex is 10:
The moisture-proof sheet according to claim 2, which is 90 to 60:40. 4. The wax-based emulsion is compounded in the moisture-proof main agent in an amount of 2 to 20 parts by weight in terms of solid content with respect to 100 parts by weight of a mixture of an acrylic synthetic resin and a synthetic rubber latex. The moisture-proof sheet according to claim 2, wherein: 5. The coating layer is 10 to 3 in terms of solid content.
The moisture-proof sheet according to claim 1, wherein the moisture-proof sheet is provided at 0 g / m ² . 6. The moisture-proof sheet according to claim 1, wherein the inorganic pigment is ground calcium carbonate having an average particle size of 5 μm to 50 μm. 7. The acrylic synthetic resin is styrene.
The moisture-proof sheet according to claim 2, which is an acrylic synthetic resin. 8. The moisture-proof sheet according to claim 2, wherein the synthetic rubber-based latex is a styrene-butadiene-based latex. 9. A coating layer containing an acrylic synthetic resin, a synthetic rubber latex, a wax emulsion and an inorganic pigment is provided on both sides of a paper substrate, and the coating amount of one coating layer is solid. It is 10 g / m ^{2 to} 30 g / m ² in terms of minutes, and the coating amount of the coating layer on the opposite surface is 1 g / in terms of solids.
m ² to a 10 g / m ^2, moisture permeability according to JISZ 0208 is not more than 20 g / m ² · 24h moistureproof sheet.