JPH07179632A - Sheet or film excellent in antiblocking and slip properties and its production - Google Patents

Abstract

PURPOSE:To improve the antiblocking and slip properties of a sheet or film without detriment to its smoothness or transparency by atomizing a suspension comprising starch particles and water and/or an alcohol and applying the resulting very fine droplets having specified sized to the sheet or film. CONSTITUTION:A suspension of starch particles is atomized into very fine droplets with droplet sizes of 300mum or lower, pref. 10-100mum, and applied to the surface of a sheet or film to film a coating layer with a thickness of 100mum or lower, pref. 5-10mum. Raw starch or a sol. starch pref. having an average particle size of 5-20mum may be used, and 10-20g of it is suspended in 1lambda of water and/or an alcohol. The suspension is atomized at normal temp. and applied with a spray nozzle, etc. A suitable sheet or film is or made from polypropylene, etc., and having a density of 0.9g/cm<3> or higher, a thickness of 10-1,000mum, a smoothness of 1s or lower, a surface gloss of 120 or higher, and a total haze of 10% of lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet or film having excellent blocking resistance and slipperiness, which is useful in the packaging industry and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, when a sheet or film having a smooth surface is wound into a roll or stacked in a sheet, or when its own weight or external force is applied, blocking occurs, slippage is poor, There is a problem in that processing work is hindered. The smoothness of the surface, the slippage of the film or sheet, and the anti-blocking property are trade-offs, and there is a desire to solve them, but at the present stage, we endure by finding a compromise between them. Is the reality.

That is, for example, a method of kneading resin fine powder into a material of a sheet or a film or coating the surface of the material has been proposed. According to this method, slipperiness is obtained, but blocking resistance (anti-blocking) is insufficient, and the fine resin powder to be kneaded is expensive, resulting in cost increase. is there. Next, a method of kneading an inorganic material into a material of a sheet or a film or coating the surface of the material has been proposed. According to this method, although a sheet or film excellent in slipping property and anti-blocking property can be obtained, there is a problem that the transparency of the sheet or film is hindered or the sheet or film is scratched when they are rubbed with each other. .

Further, a method has been proposed for solving the above-mentioned problems by forming minute convex portions on the sheet surface, but not only transparency is impaired, but also the film forming method is limited. In addition, there is a problem that a special device is required. Further, a method of directly sprinkling starch granules on the surface of a sheet or film has been practiced for a long time, but powder is blown on the surface, which is not preferable in appearance and adversely affects printing, and uniform application is difficult. There is a problem.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks and provides a sheet or film having a smooth surface with excellent blocking resistance and slipperiness without impairing the smoothness thereof. Another object of the present invention is to provide a method for inexpensively producing such a sheet or film, and a sheet or film obtained by this method, which is excellent in blocking resistance and slipperiness.

[0006]

That is, the first aspect of the present invention is
In addition, a suspension obtained by mixing starch granules with water and / or alcohol is made into a fine mist or fine mist of 300 μm or less, and then applied on the surface of the sheet or film, and the surface of the sheet or film has a thickness of 100 μm or less. It is intended to provide a method for producing a sheet or film excellent in blocking resistance and slipperiness, which is characterized by forming a coating film.

Further, the present invention secondly provides a suspension of starch granules mixed with water and / or alcohol to 300 μm.
After making the following fine mist or fine mist, apply it on the surface of the sheet or film, and apply a thickness of 10 on the surface of the sheet or film.
The present invention provides a sheet or film excellent in blocking resistance and slipperiness, which is obtained by forming a coating film having a thickness of 0 μm or less. This second sheet or film of the present invention is obtained by the first method of the present invention.

In the method of the present invention, a suspension of starch granules mixed with water and / or alcohol is used. Here, either raw starch or soluble starch may be used as the starch, but the average grain size is 1-5.
It is preferable to use one having a thickness of about 0 μm, particularly 5 to 20 μm. If the size of the starch granules is too large, white powder will precipitate, which is not preferable.

In the method of the present invention, water and / or alcohol is used as a solvent for suspending the above-mentioned starch granules to form a suspension. Thus, as the solvent, either water or alcohol, or a mixed solution thereof can be used. As such a solvent, it is preferable to use a solvent at about room temperature. If you raise the temperature,
It is not preferable because the starch granules swell and gelatinize. In the method of the present invention, the starch granules are in the proportion of 5 to 50 g, preferably 10 to 1 liter of water and / or alcohol.
Used at a rate of 20 g. Here, if the amount of starch granules used is too large, agglomerates and white powder precipitates, while if the amount of starch granules used is too small, the anti-blocking effect is lost, which is not preferable. The starch granules are mixed with water and / or alcohol in the proportions given above to obtain a suspension.

In the method of the present invention, the suspension obtained as described above is made into a fine mist, specifically 300
A fine mist or fine mist having a size of less than or equal to μm, preferably 10 to 100 μm, is applied to the surface of the sheet or film. The size of the atomized suspension particles (water droplets) is 300μ.
If it exceeds m, the object to be coated will be wet, or starch particles will agglomerate and white powder will precipitate, which is not preferable. The surface of the sheet or film may be coated with, for example, a spray nozzle.

In this way, a coating film having a thickness of 100 μm or less, preferably about 5 to 10 μm is formed on the surface of the sheet or film. Here, if the thickness of the coating film exceeds 100 μm, the object to be coated may be wet, or starch particles may agglomerate and white powder may precipitate, which is not preferable.

As the sheet or film, a sheet or film having a smooth surface and excellent transparency is targeted. Specific examples of the material of the sheet or film having a smooth surface and excellent transparency include polypropylene, polyethylene terephthalate, polycarbonate, and various engineering plastics. The density of these resins may be 0.9 g / cm ³ or more, and the thickness of the sheet or film is about 10 to 1000 μm. The sheet or film having a smooth surface and excellent transparency (highly transparent / high gloss) used in the present invention specifically includes smoothness of 1 s or less (1
μ), surface glossiness of 120 or more and total haze of 10% or less.

As the sheet or film used in the method of the present invention, a sheet or film which has been previously subjected to surface treatment such as corona discharge treatment on the surface to which the suspension is applied to improve its wettability is used. You can also Further, not only a single layer sheet or film but also a laminated sheet may be used.

As described above, it is possible to produce a sheet or film having a smooth surface and excellent blocking resistance and slipperiness. It is the second aspect of the present invention to provide a sheet or film thus obtained.

[0015]

EXAMPLES The present invention will now be described in more detail with reference to examples.

Example 1 As a coating solution, 20 g of soluble starch (average particle size: 15 μm) was mixed in 1 liter of water, and while stirring this,
Atomization of about 20 μm with a fine atomizing nozzle, transparent polypropylene sheet (thickness: mm, surface gloss: 130 °, total haze: 2.6%, coating surface corona discharge treated, wet A film having a thickness of around 20 μm was applied on the surface having a tension of 52 dyne / cm ² ) to obtain a sheet having a thickness of around 20 μm. The results of evaluating the physical properties of the obtained sheet are shown in Table 1.

The blocking property was evaluated by the following 3 grades of the degree of blocking when 100 sheets of the obtained sheets were stacked and a pressure of 7 kg / cm ² was applied thereto [A = no blocking, Δ = blocking 10% or less, × = blocking 10% or more]. The dynamic friction coefficient was measured according to JIS K 7125. Further, the transparency was visually evaluated by the following three grades [◎ =
No cloudiness, △ = Slightly cloudy, × = Cloudy.] Next, the scratch resistance was evaluated by visually observing the state of the appearance when the coated surface and the non-coated surface were rubbed together and rubbed with a finger in the following three levels [◎ = no scratches, ○ = slight scratches, △ = large scratches]. Furthermore, the printability (offset) can be confirmed by visually observing the uniformity of ink and rubbing scratch resistance with a nail.
Both were evaluated comprehensively in the following three grades [A = ink is uniform and scratch resistance is good, Δ = ink is uniform, but scratch resistance is a little weak, x = ink is not uniform, scratch resistance is weak ]. In addition, whether or not the drying step after coating is necessary for the drying is indicated by "necessary" or "unnecessary".

Comparative Example 1 In Example 1, except that the coating solution prepared by suspending soluble starch in water was not used (not coated).
A sheet was obtained in the same manner as in Example 1. The results of evaluating the physical properties of the obtained sheet are shown in Table 1.

Comparative Example 2 In Example 1, instead of the coating solution prepared by suspending soluble starch in water, silicone resin fine powder (spherical, particle size 2 to 4.5 μm) was added to 1 liter of water. Example 1 except that 0.5 g was added.
A sheet was obtained in the same manner as in. The results of evaluating the physical properties of the obtained sheet are shown in Table 1.

Comparative Example 3 The procedure of Example 1 was repeated except that the fluororesin fine powder (dispersion 30% concentration) was used in place of the coating solution prepared by suspending soluble starch in water. Got a sheet. The results of evaluating the physical properties of the obtained sheet are shown in Table 1.

Comparative Example 4 A sheet was obtained in the same manner as in Example 1 except that the atomizing nozzle was changed to a fog of about 500 μm. The results of evaluating the physical properties of the obtained sheet are shown in Table 1.

Comparative Example 5 A sheet was obtained in the same manner as in Example 1 except that the thickness of the coating film was changed to 150 μm. The results of evaluating the physical properties of the obtained sheet are shown in Table 1.

[0023]

[Table 1]

[0024]

INDUSTRIAL APPLICABILITY According to the method of the present invention, for a sheet or film having a smooth surface, a sheet or film excellent in blocking resistance and slipperiness can be obtained at low cost without impairing the smoothness and transparency. Can be obtained. Furthermore, according to the method of the present invention, it is possible to obtain a sheet or film that is not easily scratched, is harmless, has no adverse effect on subsequent secondary processing (printing, adhesion), and does not require drying after application. it can. Further, the sheet or film obtained by the method of the present invention is excellent in smoothness and transparency, and is excellent in blocking resistance and slipperiness as well as being resistant to scratches. Therefore, the sheet or film obtained by the method of the present invention can be effectively used particularly in the packaging industry.

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[Procedure amendment]

[Submission date] July 8, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

Further, a method has been proposed for solving the above-mentioned problems by forming minute convex portions on the sheet surface, but not only transparency is impaired, but also the film forming method is limited. In addition, there is a problem that a special device is required. Furthermore, the method of directly sprinkling starch granules on the surface of a sheet or film has been practiced for a long time, but powder is blown on the surface, which is not preferable in appearance and is not suitable for printing.
Adversely affect. It is difficult to apply a small amount and evenly
This is because.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

That is, the first aspect of the present invention is
In addition, a suspension obtained by mixing starch granules with water and / or alcohol is made into a fine mist or fine mist of 300 μm or less and then applied to the surface of a sheet or film, which is blocking resistance and slipperiness. And a method for producing a sheet or film excellent in

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

Further, the present invention secondly provides a suspension of starch granules mixed with water and / or alcohol to 300 μm.
Blocking resistance obtained by applying to the surface of a sheet or film after making the following fine mist or fine mist,
It is intended to provide a sheet or film having excellent slipperiness. This second sheet or film of the present invention is obtained by the first method of the present invention.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

In the method of the present invention, the suspension obtained as described above is made into a fine mist, specifically 300
A fine mist or fine mist having a size of less than or equal to μm, preferably 10 to 100 μm, is applied to the surface of the sheet or film. The size of the atomized suspension particles (water droplets) is 300μ.
If it exceeds m, the material to be coated will be extremely wet and it will take time to dry.
It takes. Also, the application to the surface of the sheet or film,
For example, a spray nozzle or the like may be used.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

In this way, a coating film having a thickness of 100 μm or less, preferably about 5 to 10 μm is formed on the surface of the sheet or film. If the thickness of the coating film exceeds 100 μm, the material to be coated will be extremely wet and it will take time to dry.
It

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

As the sheet or film, a sheet or film having a smooth surface and excellent transparency is targeted. As a material of such a sheet or film having a smooth surface and excellent transparency, specifically, polypropylene, polyethylene terephthalate, polycarbonate,
In addition to polystyrene and the like , various engineering plastics and the like can be mentioned. The thickness of the sheet or film is 10
It is about 1000 μm. Specifically, the sheet or film having a smooth surface and excellent transparency (high transparency / high gloss) used in the present invention has a smoothness of 1 s or less (1 μ),
The surface glossiness is 120 or more and the total haze is 10% or less.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Example 1 As a coating solution, 20 g of soluble starch (average particle size: 15 μm) was mixed in 1 liter of water, and while stirring this,
Atomization of about 20 μm with a fine atomizing nozzle, transparent polypropylene sheet ( thickness 0.3 mm , surface gloss 1
30 degree, total haze is 2.6%, coating surface is corona discharge treated, wetting tension = 52 dyne / cm ² ), and a coating thickness of about 20 μm is applied to the surface of the sheet. A coating film with a thickness of around 20 μm is formed, water evaporates, and the surface has
A sheet having finely dispersed particles was obtained. The results of evaluating the physical properties of the obtained sheet are shown in Table 1.

Claims (2)

[Claims] 1. A suspension in which starch granules are mixed with water and / or alcohol is made into a fine mist or fine mist of 300 μm or less and then applied on the surface of a sheet or film to obtain a thickness on the surface of the sheet or film. A method for producing a sheet or film having excellent blocking resistance and slipperiness, which comprises forming a coating film having a thickness of 100 μm or less. 2. A suspension in which starch granules are mixed with water and / or alcohol is made into a fine mist or fine mist of 300 μm or less and then applied onto the surface of a sheet or film to obtain a thickness on the surface of the sheet or film. A sheet or film having excellent blocking resistance and slipperiness, which is obtained by forming a coating film having a thickness of 100 μm or less.