KR102267153B1 - Producing Method of Amorphous Alumino silicate - Google Patents

Abstract

The present invention relates to a method for producing an amorphous aluminosilicate, and more particularly, to a method for producing an amorphous aluminosilicate having excellent anti-blocking properties and optical properties.

Description

Manufacturing method of amorphous alumino silicate {Producing Method of Amorphous Alumino silicate}

The present invention relates to amorphous aluminosilicates.

Films or sheets with smooth surfaces stick to each other and do not come off easily. This phenomenon is called blocking, and the opening becomes worse in the production process or post-processing stage, which causes a lot of inconvenience in use as well as product defects.

In general, when forming a film, if the distance between the die and the nip-roll is widened and the cooling time is extended to maintain the temperature of the nip roll below the softening point of the resin, the blocking occurrence rate is reduced. In addition, fine particles of inorganic minerals such as silica, diatomaceous earth, kaolin and talc are added to roughen the film surface to form a thin space between adjacent film layers, thereby preventing adhesion and reducing blocking. However, this method cannot sufficiently prevent the blocking phenomenon, but also has a problem of lowering the optical properties of the film, so a method capable of more effectively preventing the blocking phenomenon is required.

In order to solve the blocking problem, research on an anti-blocking agent is in progress. An anti-blocking additive is an additive that can be used by mixing it with a resin in the production of a film, but a sheet. Recently, research on using aluminosilicate as an anti-blocking additive has been conducted, but due to the crystalline structure of aluminosilicate, there is a limitation in using it as an anti-blocking additive for polymer films requiring transparency and high physical properties. It is difficult to apply in the required field.

In order to solve the above problem, synthesized silica has been used recently, but it is difficult to make the shape of the particles uniform, so after the production is completed, the physical properties are matched by classifying the product by particle size through classification in the post-process. , there is a problem that the production efficiency is low. In addition, there is a limitation in increasing the addition amount due to the high specific surface area of silica, and in particular, in the case of a process of manufacturing a master batch, there is a problem in that it is difficult to make a highly concentrated product.

Therefore, in the market, it is possible to manufacture a masterbatch with a high concentration, and anti-blocking additives with excellent anti-blocking properties and optical properties are required.

Korean Patent Publication No. 10-0393538

It is an object of the present invention to provide a method for producing amorphous aluminosilicate that is capable of producing a masterbatch of high concentration, has excellent anti-blocking properties and optical properties, and has excellent processability.

the present invention

a) gelling by mixing an aqueous solution containing a silica source and an alumina source;

b) preparing an aluminosilicate by hydrothermal synthesis of the gelled product;

c) reacting the prepared aluminosilicate with an inorganic acid, and

d) heat-treating the product obtained by reacting with the inorganic acid

It provides a method for producing an amorphous aluminosilicate comprising a.

In one embodiment according to the present invention, the amorphous aluminosilicate ^{may satisfy a specific surface area of 100 m 2} /g or less.

In one embodiment according to the present invention, the aluminosilicate may include 300 to 400 parts by weight of the aluminosilicate based on 100 parts by weight of the inorganic acid.

In one embodiment according to the present invention, the inorganic acid may include at least one selected from sulfuric acid, nitric acid and hydrochloric acid.

In one embodiment according to the present invention, the inorganic acid may include at least one selected from sulfuric acid, nitric acid and hydrochloric acid in a concentration of 5 to 20%.

In one embodiment according to the present invention, the heat treatment may be performed at 200 to 500 ℃.

In one embodiment according to the present invention, the aqueous solution may contain 10 to 150 parts by weight of the silica source based on 100 parts by weight of the alumina source.

In one embodiment according to the present invention, the hydrothermal synthesis may be a reaction at 80 to 150 ℃.

The present invention also provides an anti-blocking additive (Anti-blocking Agent) comprising an amorphous aluminosilicate prepared by the method for producing an amorphous aluminosilicate according to an embodiment of the present invention.

In one embodiment according to the present invention, the amorphous aluminosilicate may be an anti-blocking additive that satisfies the following formulas 1 and 2.

Equation 1: 5㎛ ≤ D ₅₀ ≤8㎛

(In Equation 1, D50 is the particle size corresponding to 50% of the cumulative particle size distribution)

Equation 2: 2㎛ ≤ D ₉₀ ≤10㎛

(In Equation 2, D90 is the particle size corresponding to 90% of the cumulative particle size distribution)

In one embodiment according to the present invention, the amorphous aluminosilicate may be an anti-blocking additive that satisfies a ^{specific surface area of 100 m 2 /g or less.}

The present invention also provides a polyolefin film comprising an anti-blocking additive according to an embodiment of the present invention.

In one embodiment according to the present invention, when the polyolefin film contains 0.1 to 1 part by weight of the anti-blocking additive based on 100 parts by weight of the polyolefin resin, the haze value may be 60% or less.

The present invention also comprises the steps of preparing an amorphous aluminosilicate according to an embodiment of the present invention; extruding the polyolefin resin; and introducing the amorphous aluminosilicate during the extrusion process. It provides a method for producing a polyolefin film comprising an anti-blocking additive comprising a.

The method for producing amorphous aluminosilicate according to an embodiment of the present invention has the advantage that a high concentration masterbatch can be prepared. In addition, by improving the uniformity of the particles and lowering the specific surface area, there is an advantage in that not only the anti-blocking effect is improved, but also the optical properties and processability are improved.

Even if the effects are not explicitly mentioned in the present invention, the effects described in the specification expected by the technical features of the present invention and the inherent effects thereof are treated as described in the specification of the present invention.

1 shows a scanning electron microscope photograph of amorphous aluminosilicate particles prepared according to an embodiment of the present invention.
Figure 2 shows the particle size distribution of the amorphous aluminosilicate particles prepared according to an embodiment of the present invention.

Hereinafter, a method for producing an amorphous aluminosilicate according to the present invention will be described in detail. At this time, unless there are other definitions in the technical terms and scientific terms used, it has the meaning commonly understood by those of ordinary skill in the art to which this invention belongs, and in the following description, the subject matter of the present invention may be unnecessarily obscured. Descriptions of possible known functions and configurations will be omitted.

The present invention comprises the steps of: a) gelling an aqueous solution containing a silica source and an alumina source;

b) preparing an aluminosilicate by hydrothermal synthesis of the gelled product;

c) reacting the prepared aluminosilicate with an inorganic acid, and

d) heat-treating the product obtained by reacting with the inorganic acid

It relates to a method for producing an amorphous aluminosilicate comprising a.

The method for producing an amorphous aluminosilicate according to the present invention has the advantage of not only improving processability, but also enabling the preparation of a high concentration masterbatch, and the film containing the amorphous aluminosilicate produced by the present invention is excellent It has the advantage of exhibiting anti-blocking properties and optical properties.

Specifically, in the method for producing an amorphous aluminosilicate according to the present invention, a silica source and an aqueous solution containing an alumina source are uniformly mixed, gelled, and hydrothermal synthesis is performed to prepare an aluminosilicate, which is then reacted with an inorganic acid again. Through the heat treatment method, there is an advantage that amorphous aluminosilicate having a more uniform particle size and a low specific surface area can be prepared, and there is an advantage that can be applied to products requiring high transparency due to improved optical properties.

The amorphous aluminosilicate prepared by the method for producing an amorphous aluminosilicate according to an embodiment of the present invention may satisfy the following formulas 1 and 2.

Equation 1: 5㎛ ≤ D ₅₀ ≤8㎛

Equation 2: 2㎛ ≤ D ₉₀ ≤10㎛

In Equation 1, D ₅₀ is the particle size corresponding to 50% of the cumulative particle size distribution of amorphous aluminosilicate, and in Equation 2, D ₉₀ is the particle size corresponding to 90% of the cumulative particle size distribution of amorphous aluminosilicate. The specific surface area of the amorphous aluminosilicate having the above particle size range ^{may satisfy 100 m 2} /g or less. Specifically, the amorphous aluminosilicate may have a specific surface area of 30 to 100 m ² /g, but is not limited thereto. More specifically, the present invention converts an aluminosilicate having a crystalline structure into an amorphous aluminosilicate having a uniform particle size and specific surface area in the above-described ranges through reaction with an inorganic acid. In general, a high specific surface area value limits the addition amount as an additive to a certain extent, making it difficult to prepare a high concentration masterbatch. Therefore, since the particle size and specific surface area of the amorphous aluminosilicate according to the present invention have the above ranges, it is possible not only to suppress the change in anti-blocking properties due to size deviation, but also to use a high concentration of the masterbatch. It has the advantage of exhibiting excellent anti-blocking properties and optical properties.

In the method for producing an amorphous aluminosilicate according to an embodiment of the present invention, the aqueous solution may contain 10 to 150 parts by weight of a silica source, more preferably 20 to 90 parts by weight, based on 100 parts by weight of the alumina source. In general, there is a problem in that the addition of the anti-blocking agent reduces the optical properties of the film including the same. However, when an alumina source and a silica source are included in the above range, amorphization may be more likely to occur in the process of reacting with the inorganic acid of step c). Accordingly, the optical properties of the film including the same may maintain better optical properties. The alumina source may include at least one of sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum hydroxide, aluminum alkoxide, and alumina gel, but is not limited thereto. In addition, the silica source may include at least one of colloidal silica, fumed silica, sodium silicate and silica gel, but is not limited thereto.

After preparing an aqueous solution using a solvent and a mixture containing a silica source and an alumina source in the above range, the mixture is stirred at room temperature to gel. The solvent may be distilled water, but is not limited thereto. In addition, the mixture containing the silica source and the alumina source may contain 20 to 30 parts by weight based on 100 parts by weight of the solvent, but is not limited thereto. Specifically, the stirring may be performed at 200 to 600 rpm, preferably 300 to 500 rpm, and may be performed for 1 to 5 hours, preferably 1 to 3 hours, but is not limited thereto. When stirring in the above range, it can be gelled more sufficiently.

The gelled product undergoes hydrothermal synthesis, and then undergoes amorphization and heat treatment through a reaction with an inorganic acid. Through this process, the amorphous aluminosilicate of the present invention can be finally prepared.

Specifically, in the method for producing amorphous aluminosilicate according to an embodiment of the present invention, the hydrothermal synthesis may be a reaction at 80 to 150 ℃, more preferably 80 to 120 ℃. Specifically, it is more economical as the reaction time is reduced during hydrothermal synthesis in the above temperature range, and the particle size is not sensitively changed according to the stirring speed. Therefore, the aluminosilicate that has undergone hydrothermal synthesis in the above temperature range can be converted into an amorphous alumina silicate having a more uniform particle size and specific surface area through the amorphous process according to step c) described above. More specifically, the hydrothermal synthesis is preferably performed for 1 to 12 hours, preferably 1 to 8 hours, but is not limited thereto. The precipitate prepared through the hydrothermal synthesis, that is, the aluminosilicate having crystallinity may be washed three or more times with distilled water, but is not limited thereto.

The above-described crystalline aluminosilicate undergoes an amorphous process through a reaction with an inorganic acid. Specifically, through a reaction with an inorganic acid, the crystal structure of the crystalline aluminosilicate is broken and converted into an aluminosilicate having an amorphous structure. In the method for producing an amorphous aluminosilicate according to an embodiment of the present invention, the aluminosilicate may include 300 to 400 parts by weight, more preferably 330 to 380 parts by weight, based on 100 parts by weight of the inorganic acid. In the above range, the bonding between the aluminum and silicon elements is weakened, and thus the crystal structure of the aluminosilicate is weakened, so that the aluminosilicate can more easily participate in the amorphization reaction.

Specifically, the inorganic acid may include at least one selected from sulfuric acid, nitric acid and hydrochloric acid. More specifically, the inorganic acid may have a concentration of 5 to 20%, more preferably 10 to 20%. In addition, the reaction with the inorganic acid may be carried out at 200 to 1000 rpm, preferably at 400 to 900 rpm for 1 to 5 hours, preferably for 1 to 3 hours. The reaction with the inorganic acid can be carried out at room temperature, but it is more preferred to carry out while heating at 40 to 60 °C. It is possible to prepare an amorphous aluminosilicate having a more uniform particle size and specific surface area than in the above range, so there is an advantage in that not only the anti-blocking effect but also the optical properties can be improved. In addition, it is possible to shorten the amorphous reaction time of the alumina silicate and at the same time reduce the washing time after the reaction, thereby reducing the overall process time. Specifically, the washing may be performed three or more times with distilled water, but is not limited thereto. The inorganic acid may be added in the above-mentioned gelation step a), but in this case, the prepared alumino silica has porosity, so it exhibits a high specific surface area and causes diffuse reflection to deteriorate optical properties. Since the high specific surface area limits the amount of additives added to a certain degree, it is difficult to prepare a high-concentration masterbatch, and it is difficult to apply to fields requiring transparency.

In the method for producing an amorphous aluminosilicate according to an embodiment of the present invention, the heat treatment may be performed at 200 to 500° C., but preferably, heat treatment at 300 to 400° C. is more advantageous. More specifically, by performing the heat treatment within the above range, not only the amorphous aluminosilicate can be sufficiently dried, but also the reaction residue and the like can be sufficiently removed to obtain the amorphous aluminosilicate in a more uniform particle state. This is because, when there is residual moisture, a bubbling phenomenon occurs in the manufacturing process of the masterbatch, resulting in a problem in the process. Specifically, the heat treatment may be performed for 2 to 12 hours, preferably 3 to 10 hours, and more preferably 4 to 8 hours, but is not limited thereto.

The present invention also provides an anti-blocking additive, and the anti-blocking agent according to the present invention includes an amorphous aluminosilicate prepared by the amorphous aluminosilicate manufacturing method of an embodiment of the present invention. In the anti-blocking additive according to an embodiment of the present invention, the amorphous aluminosilicate may satisfy Equations 1 and 2 below.

Equation 1: 5㎛ ≤ D ₅₀ ≤8㎛

Equation 2: 2㎛ ≤ D ₉₀ ≤10㎛

In Equation 1, D ₅₀ is the particle size corresponding to 50% of the cumulative particle size distribution of amorphous aluminosilicate, and in Equation 2, D ₉₀ is the particle size corresponding to 90% of the cumulative particle size distribution of amorphous aluminosilicate. The specific surface area of the amorphous aluminosilicate having the above particle size range ^{may satisfy 100 m 2} /g or less. Specifically, the amorphous aluminosilicate may have a specific surface area of 30 to 100 m ² /g, but is not limited thereto. More specifically, the present invention converts an aluminosilicate having a crystalline structure into an amorphous aluminosilicate having a uniform particle size and specific surface area in the above-mentioned ranges through reaction with an inorganic acid. In general, a high specific surface area value limits the addition amount as an additive to a certain extent, making it difficult to prepare a high concentration masterbatch. Therefore, since the particle size and specific surface area of the amorphous aluminosilicate according to the present invention are within the above ranges, it is possible not only to suppress the change in anti-blocking properties due to size deviation, but also to use a high concentration of the masterbatch. There is no such thing, and it has the advantage of exhibiting excellent anti-blocking properties and optical properties.

The present invention also provides a polyolefin film comprising an anti-blocking additive according to an embodiment of the present invention. Polyolefin refers to a compound having a double bond between carbons, that is, a polymer obtained by polymerizing olefin. Specifically, the polyolefin may include, but is not limited to, polyethylene, polypropylene, and polyisobutylene. Specifically, by adding the anti-blocking additive, the blocking phenomenon of the polyolefin film can be significantly reduced, and excellent optical properties are provided, so excellent transparency of the polyolefin film without problems such as a decrease in transparency due to the addition of the anti-blocking additive has the advantage of being able to represent

In the polyolefin film according to an embodiment of the present invention, when 0.1 to 1 part by weight of the anti-blocking additive is included with respect to 100 parts by weight of the polyolefin resin, the haze value may be 60% or less. In general, due to the crystalline structure of the anti-blocking additive, the addition of the anti-blocking additive reduces the transparency of the polyolefin film requiring transparency, there is a problem of increasing the degree of haze. However, the polyolefin film according to an embodiment of the present invention, by including the anti-blocking additive in the above range, not only can significantly improve the anti-blocking effect, but also can exhibit a haze value of 60% or less, so anti-blocking properties and optical properties can be simultaneously improved. Specifically, the haze value may be a haze value for a polyolefin film with an average thickness of 50 to 100 μm.

The present invention also comprises the steps of preparing an amorphous aluminosilicate by the method for preparing an amorphous aluminosilicate of an embodiment of the present invention, extruding a polyolefin resin; And it provides a method for producing a polyolefin film comprising an anti-blocking additive comprising the step of introducing the amorphous aluminosilicate during the extrusion process. Specifically, the polyolefin film including the anti-blocking additive prepared according to the present invention may exhibit a haze value of 60% or less. Therefore, without the problem of reducing the transparency of the film due to the addition of the anti-blocking additive that occurs in general, the polyolefin film containing the anti-blocking additive according to the present invention has the advantage of maintaining excellent anti-blocking effect while maintaining excellent optical properties. have.

Hereinafter, the present invention will be described in detail by way of Examples, but these are for describing the present invention in more detail, and the scope of the present invention is not limited by the Examples below.

An aqueous solution was prepared by adding 100 g of sodium silicate to 140 ml of distilled water, and 120 g of sodium aluminate was added to 640 ml of distilled water to prepare an aqueous solution, and then the two aqueous solutions were sufficiently mixed and then put into a 1L reactor. Then, the gel was subjected to aging treatment at room temperature at 400 rpm on a mechanical stirrer for 1 hour. After the gelled gel composition was reacted at 95° C. for 1 hour, the precipitate was separated and washed 5 times with distilled water. The washed precipitate was put back into a 1L reactor together with 200 ml of distilled water, and then stirred at 400 rpm for 1 hour. Then, the mixture was mixed with 370 ml of 15% sulfuric acid solution and stirred again at 400 rpm for 1 hour to react, filtered to separate the precipitate, and washed with distilled water 5 times or more. Finally, the precipitate was sufficiently heat-treated at 350° C. for 6 hours to obtain an amorphous aluminosilicate powder.

The specific surface area of the prepared amorphous aluminosilicate powder was measured by the BET measurement method, and the results are shown in Table 1.

In Example 1, the same procedure was performed except that 18% sulfuric acid solution was used instead of 15% sulfuric acid solution, and after mixing with sulfuric acid solution, stirring was performed at 800 rpm instead of 400 rpm.

The same procedure was carried out in Example 1, except that 20% sulfuric acid solution was used instead of 15% sulfuric acid solution, and after mixing the sulfuric acid solution, the mixture was stirred for 3 hours instead of 1 hour.

The same procedure was carried out in Example 1, except that 18% sulfuric acid solution was used instead of 15% sulfuric acid solution, and after mixing the sulfuric acid solution, the mixture was stirred while heating at 50° C. instead of room temperature.

(Comparative Example 1)

After sufficiently mixing 620 ml of a 10% sulfuric acid solution with 380 ml of an aqueous solution containing 40% by weight of sodium silicate, it is put into a 1L reactor. Then, the gel was subjected to aging treatment at room temperature at 400 rpm on a mechanical stirrer for 1 hour. After the gelled gel composition was reacted at 95° C. for 1 hour, the precipitate was separated and washed 5 times with distilled water. Finally, the precipitate was heat-treated at 200° C. for 5 hours to obtain silica powder.

The specific surface area of the prepared silica powder was measured by the BET measurement method, and the results are shown in Table 1.

Specific surface area (m ² /g) Example 1 80 Example 2 78 Example 3 75 Example 4 70 Comparative Example 1 300

As can be seen in Table 1, it can be seen that the amorphous aluminosilicate prepared according to an embodiment of the present invention exhibited a lower specific surface area value than the silica according to the comparative example. Therefore, it can be seen that the aluminosilicate of an amorphous structure prepared according to an embodiment of the present invention not only enables the preparation of a highly concentrated product, for example, a masterbatch, but also has excellent processability.

In addition, from FIGS. 1 and 2, it can be seen that the D ₅₀ value of the amorphous aluminosilicate particles prepared according to an embodiment of the present invention is in the range of 5 to 8 μm, and the D ₉₀ value is in the range of 2 to 10 μm. Therefore, the uniformity of the particles can be known.

During the extrusion process of 1000 g of low-density polyethylene resin (Equistar Chemicals, LP, L5906), 2.5 g of the amorphous aluminosilicate powder prepared in Example 1 was directly added to prepare a masterbatch containing an anti-blocking additive, and then, the low-density poly A polyethylene film having an average thickness of 75 μm was prepared using a blown film processing machine used for film products of tin resin.

For the prepared polyethylene film, haze was measured using BYK's Haze Gard according to ISO 147823, and the results are shown in Table 2.

In addition, the produced polyethylene film was measured for friction coefficient using a universal testing machine (UTM) according to the standard of ASTM D1894, the results are shown in Table 3.

In Example 5, the same procedure was performed except that the amorphous aluminosilicate powder prepared in Example 2 was used.

In Example 5, the same procedure was performed except that the amorphous aluminosilicate powder prepared in Example 3 was used.

In Example 5, the same procedure was performed except that the amorphous aluminosilicate powder prepared in Example 4 was used.

(Comparative Example 2)

In Example 5, the same procedure was performed except that the silica prepared in Comparative Example 1 was used.

Haze (%) Example 5 60 Example 6 57 Example 7 50 Example 8 45

As can be seen in Table 2, it can be seen that the polyethylene film prepared according to an embodiment of the present invention using amorphous aluminosilicate as an anti-blocking additive has a much lower haze. Due to these excellent optical properties, it was possible to apply to all polyolefin films as well as polyethylene films requiring transparency.

coefficient of friction Example 5 0.21 Example 6 0.20 Example 7 0.18 Example 8 0.15 Comparative Example 2 0.29

As can be seen in Table 3, it can be seen that the polyethylene film prepared according to an embodiment of the present invention using amorphous aluminosilicate as an anti-blocking additive exhibits a lower coefficient of friction. Since the low coefficient of friction indicates excellent anti-blocking properties, it can be seen that the polyethylene film prepared by using the amorphous aluminosilicate prepared according to an embodiment of the present invention as an anti-blocking additive exhibits excellent anti-blocking properties.

Claims (14)

a) gelling by mixing an aqueous solution containing a silica source and an alumina source;
b) preparing an aluminosilicate by hydrothermal synthesis of the gelled product;
c) reacting the prepared aluminosilicate with an inorganic acid, and
d) heat-treating the product obtained by reacting with the inorganic acid
includes,
The aqueous solution contains 20 to 90 parts by weight of a silica source based on 100 parts by weight of the alumina source,
The heat treatment is performed at 300 to 400 ℃ for 3 to 10 hours, a method for producing amorphous aluminosilicate. According to claim 1,
The method for producing an amorphous aluminosilicate, wherein the amorphous aluminosilicate satisfies a specific surface area of 100 m ^{2 /g or less.} According to claim 1,
The aluminosilicate is a method for producing an amorphous aluminosilicate comprising 300 to 400 parts by weight of the aluminosilicate based on 100 parts by weight of the inorganic acid. According to claim 1,
The inorganic acid is a method for producing an amorphous aluminosilicate comprising at least one selected from sulfuric acid, nitric acid and hydrochloric acid. 4. The method of claim 3,
The inorganic acid is a method for producing an amorphous aluminosilicate comprising at least one selected from sulfuric acid, nitric acid and hydrochloric acid in a concentration of 5 to 20%. delete delete According to claim 1,
The hydrothermal synthesis is a method for producing an amorphous aluminosilicate that is reacted at 80 to 150 ℃. An anti-blocking additive (Anti-blocking Agent) comprising an amorphous aluminosilicate prepared by the method for preparing an amorphous aluminosilicate according to any one of claims 1 to 5 and 8. 10. The method of claim 9,
The amorphous aluminosilicate is an anti-blocking additive that satisfies the following formulas 1 and 2.
Equation 1: 5 μm ≤ D ₅₀ ≤ 8 μm;
(In Equation 1, D ₅₀ is the particle size corresponding to 50% of the particle size cumulative distribution)
Equation 2: 2 _{μm ≤ D 90} ≤ 10 μm;
(In Equation 2, D ₉₀ is the particle size corresponding to 90% of the particle size cumulative distribution) 10. The method of claim 9,
The amorphous aluminosilicate anti-blocking additive that satisfies a specific surface area of 100 m ^{2 /g or less.} 10. A polyolefin film comprising the anti-blocking additive according to claim 9. 13. The method of claim 12,
The polyolefin film has a haze value of 60% or less when 0.1 to 1 part by weight of an anti-blocking additive is included with respect to 100 parts by weight of the polyolefin resin. A method for preparing an amorphous aluminosilicate according to any one of claims 1 to 5 and 8, comprising the steps of: preparing an amorphous aluminosilicate;
extruding the polyolefin resin; and
Injecting the amorphous aluminosilicate during the extrusion process
Method for producing a polyolefin film comprising an anti-blocking additive comprising

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