JP5417247B2 - Anti-fogging propylene resin sheet - Google Patents

Description

  The present invention relates to a propylene resin sheet excellent in antifogging property and transparency, and more particularly relates to an antifogging propylene resin sheet excellent in transparency and antifogging property and having little discoloration even when recycled.

Polystyrene, polyvinyl chloride, polyethylene terephthalate, etc., which are non-crystalline thermoplastic resins with excellent transparency, can be distinguished from each other, so they are processed into sheets, and food containers are formed by thermoforming. It is widely used as a cover material.
However, these non-crystalline resins have a problem in that the containers and lids are deformed or cracked due to poor heat resistance and shock resistance, etc. in recent years due to the increase in foods heated in microwave ovens. The material has been desired to be transparent, antifogging, heat resistant and impact resistant.
On the other hand, a crystalline polypropylene resin sheet is strong in heat resistance and impact resistance but poor in transparency, and its surface is extremely hydrophobic. There was a problem of anti-fogging property that it adhered to the surface as fine water droplets and it was difficult to distinguish the contents.

  The transparency of the polypropylene resin sheet reduces crystallinity by rapidly cooling and solidifying with a metal roll or metal belt that has been mirror-finished during sheet processing, and by copolymerizing propylene and α-olefin. In addition, a method using a polypropylene resin, a method of adding a nucleating agent to a polypropylene resin, etc. (Patent Document 1) have been improved to a practical level of transparency.

  On the other hand, the antifogging property of the polypropylene resin sheet improves the hydrophobicity by cooling and solidifying the polypropylene resin on the line at the time of sheet processing, and then applying corona treatment, plasma treatment, flame treatment, etc. It has become possible to impart antifogging properties by a method (Patent Document 2, Patent Document 3, Patent Document 4, etc.) of winding and drying a sheet while applying an antifogging agent.

However, in recent years, the reuse of resources has been actively promoted from the viewpoint of economic efficiency and environmental protection. Food containers and lids are no exception, and sheets and products coated with an antifogging agent have been required to be recycled.
In particular, when a container or a lid material is produced from a sheet by thermoforming, a sheet loss portion is inevitably generated after the container or lid material is punched out. Furthermore, it is also required to collect and recycle containers and lid products.
When reusing sheets and products, the sheets and products are pulverized and mixed with virgin raw materials, and then applied to a sheet molding machine. After pulverizing the sheets and products, they are melt-kneaded in an extruder and pellets (grains) The sheet is processed into a shape, mixed with the virgin raw material, and applied to a sheet forming machine.
In this case, although depending on the ratio of recycle use, the sheet forming process is more stable when the raw material is melt kneaded and processed into pellets (grains) because the bulk density of the raw material is more stable.

  At this time, it was found that when a polypropylene resin sheet coated with an antifogging agent or a product obtained using the same was pulverized and formed into a sheet, the color changed to marked brown. In particular, in order to stabilize the bulk density, it has become clear that more severe discoloration occurs when a crushed product of a sheet or product is melt-kneaded with an extruder and processed into a pellet.

  Thus, the polypropylene resin sheet used for solving the problem that the container and the lid are deformed or cracked due to the heat resistance failure and the impact resistance failure which are the disadvantages of the amorphous resin, In order to use it efficiently as a required container or lid, it was necessary to improve this drawback, but it has not been realized yet and its development is desired.

JP-A-4-339847 JP-A-56-166234 JP 57-80431 A Japanese Examined Patent Publication No. 61-36864

  An object of the present invention is to provide an anti-fogging propylene-based resin sheet that is excellent in transparency and anti-fogging properties and has little discoloration even when recycled.

  As a result of intensive studies to solve the above problems, the present inventors have found that a specific propylene resin composition is formed by using a specific propylene resin and a specific fatty acid metal salt blended in a specific ratio. When a specific anti-fogging agent is applied to at least one side of the propylene-based resin sheet at a specific application amount, an anti-fogging propylene-based resin sheet that is less discolored even when recycled is used while maintaining transparency and anti-fogging properties. As a result, the present invention was completed.

That is, according to the first invention of the present invention, an antifogging agent having a solid content of 0.05 to ² g / m ² is applied to at least one surface of a propylene-based resin sheet having a thickness of 0.1 to ² mm. A propylene-based resin sheet, wherein the propylene-based resin sheet is a fatty acid having 6 to 22 carbon atoms with respect to 100 parts by weight of a propylene-based resin having an MFR of 0.3 to 20 g / 10 min obtained using a Ziegler-based catalyst. And at least one fatty acid metal salt of a metal selected from calcium, sodium, zinc, lithium, aluminum or magnesium in a proportion of 0.005 to 0.04 parts by weight. On the other hand, an antifogging propylene-based resin sheet is provided, wherein the antifogging agent comprises a sucrose fatty acid ester of a fatty acid having 6 to 22 carbon atoms. The

  According to the second invention of the present invention, in the first invention, the propylene-based resin is a random copolymer having a propylene content of 100 to 90% by weight and an α-olefin content of 0 to 10% by weight. An antifogging propylene-based resin sheet is provided.

  According to a third aspect of the present invention, there is provided the antifogging propylene-based resin sheet according to the second aspect, wherein the α-olefin is ethylene.

  Furthermore, according to the fourth invention of the present invention, in any one of the first to third inventions, the haze value (HAZE value) of the 0.35 mm thick sheet is 20 or less, and the antifogging propylene A resin sheet is provided.

  According to the present invention, it is possible to provide an anti-fogging propylene-based resin sheet that is excellent in transparency and anti-fogging property and has little discoloration even when recycled. These sheets are excellent in economic efficiency and environmental friendliness, and can be suitably used in the fields of food daily necessities packaging and medical electronic parts.

  As described above, the present invention is an anti-fogging propylene resin sheet that is less discolored even when recycled by coating a specific anti-fogging agent on at least one surface of the specific propylene resin sheet.

  Hereinafter, the components of the composition for forming the antifogging propylene resin sheet of the present invention and the production method thereof, the antifogging agent, and the production method of the antifogging propylene resin sheet using them in detail, etc. explain.

[1] [Components]
1. Propylene Resin The melt flow rate MFR of the propylene resin used in the present invention is usually preferably 0.2 to 30 g / 10 minutes, more preferably 0.3 to 15 g / 10 minutes, and more preferably 0.4 to 10/10. Minutes are particularly preferred. If the MFR is less than the above, the surface during molding is roughened and the appearance of the product is impaired. If the MFR exceeds the above, the impact strength of the product is reduced.

The propylene resin used in the present invention may be a propylene homopolymer, but is preferably a random or block copolymer of propylene and an α-olefin. These may be used alone or in combination.
As the α-olefin, ethylene, butene-1, pentene-1, hexene-1,4-methyl-pentene-1, and the like can be used. Among these, a random copolymer of propylene and ethylene is preferable. In the random copolymer of propylene and ethylene, the ethylene content is preferably 0.1 to 10% by weight, more preferably 0.2 to 5% by weight, and particularly preferably 0.4 to 3.5% by weight. When the ethylene content is less than 0.1% by weight, the impact strength of the product is impaired, and when the ethylene content exceeds 10% by weight, the rigidity of the product is lowered.

The propylene-based resin used in the present invention can be obtained using a Ziegler-based catalyst. The propylene-based resin obtained by the Ziegler-based catalyst has a wide molecular weight distribution, and thus has high melt tension and little drawdown, and therefore has excellent sheet moldability and sheet thermoformability.
Propylene-based resins obtained with Ziegler-based catalysts contain catalyst residues of chlorinated substances, which cause problems such as rusting the molding machine when used for a long period of time. The chlorine content is desirably 50 ppm or less.
Moreover, the polymerization method of the propylene-based resin used in the present invention can be produced by any polymerization method, and a slurry method, a gas phase method, a bulk method, or the like can be used.
As the propylene-based resin, commercially available products can be used in addition to those obtained by the method described later. As a commercial item, as a product using a Ziegler-based catalyst, for example, a product suitable for the scope of the present invention can be used from Novatec PP (trade name) series manufactured by Nippon Polypro Co., Ltd.

2. Fatty acid metal salt The fatty acid metal salt used in the present invention is a fatty acid metal salt of a fatty acid having 6 to 22 carbon atoms, and specific examples include calcium, sodium, zinc, lithium, aluminum or magnesium fatty acid metal salts. It is done. Of these, calcium stearate, lithium stearate, zinc stearate, aluminum stearate and the like are particularly suitable.
The amount of the fatty acid metal salt used in the present invention is in the range of 0.005 to 0.04 parts by weight with respect to 100 parts by weight of the propylene-based resin. If this range is exceeded, discoloration during playback may become severe.
The fatty acid metal salt is generally used as a neutralizing agent for a propylene-based resin mainly using a Ziegler-based catalyst, centering on calcium stearate. Since Ziegler-based catalysts contain chlorine-based compounds, the chlorine-based material remaining in the propylene-based resin usually solves problems such as rusting the molding machine when the propylene-based resin is used for a long time. It is known that about 0.05 to 0.1 part by weight is added to 100 parts by weight of the propylene resin.
However, in the configuration of the present invention, it has been confirmed that the use within this range causes severe discoloration during the recycling of the antifogging propylene resin sheet.

3. Nucleating Agent In the present invention, at least one nucleating agent selected from an aromatic carboxylic acid metal salt-based, aromatic phosphate metal salt-based, sorbitol-based, or amine-based nucleating agent may be used.

  Examples of the aromatic carboxylic acid metal salt nucleating agent include aluminum benzoate, potassium benzoate, sodium benzoate, lithium benzoate, aluminum di-para-t-butylbenzoate, di-para-t-butylbenzoate. Examples thereof include titanium oxide, chromium di-para-t-butylbenzoate, aluminum hydroxy-di-t-butylbenzoate, aluminum-p-butylbenzoate, and sodium β-naphthoate.

  Examples of the aromatic metal phosphate nucleating agent include sodium bis (4-t-butylphenyl) phosphate, lithium bis (4-t-butylphenyl) phosphate, and bis (4-t-butylphenyl). ) Aluminum phosphate, 2,2'-methylene-bis (4,6-di-t-butylphenyl) sodium phosphate, 2,2'-methylene-bis (4,6-di-t-butylphenyl) ) Lithium phosphate, 2,2′-methylene-bis (4,6-di-t-butylphenyl) aluminum phosphate, 2,2′-methylidene-bis (4,6-di-t-butylphenyl) ) Calcium phosphate, 2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphate sodium salt, 2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphorus Lithium salt, 2 2'-ethylidene-bis (4,6-di-t-butylphenyl) aluminum phosphate, bis- (4-tert-butylphenyl) calcium phosphate, and the like are commercially available. “Adeka Stub NA-11”, “Adeka Stub NA-21”, “Adeka Stub NA-71” and the like sold by the company are preferably mentioned.

  Examples of the sorbitol-based nucleating agent include dibenzylidene sorbitol, 1,3-di (methylbenzylidene) sorbitol, 2,4-di (methylbenzylidene) sorbitol, 1,3-di (ethylbenzylidene) sorbitol, 2,4 -Di (ethylbenzylidene) sorbitol, 1,3-di (butylbenzylidene) sorbitol, 2,4-di (butylbenzylidene) sorbitol, 1,3-di (methoxybenzylidene) sorbitol, 2,4-di (methoxybenzylidene) Examples include sorbitol, 1,3-di (ethoxybenzylidene) sorbitol, 2,4-di (ethoxybenzylidene) sorbitol, 1.3-chlorobenzylidene, 2.4-methylbenzylidene sorbitol, mono (methyl) dibenzylidene sorbitol and the like. .

  Among these nucleating agents, p-t-butylbenzoate aluminum, 2,2′-methylenebis (4,6-di-t-butylphenyl) sodium phosphate, 2,2′-methylenebisphosphate (4 , 6-Di-t-butylphenyl) aluminum, p-methyl-benzylidene sorbitol, p-ethyl-benzylidene sorbitol, 1,3: 2,4-dibenzylidene sorbitol, 1,3: 2,4-bis (p- Methylbenzylidene) sorbitol, 1,3-p-chlorobenzylidene-2,4-p-methylbenzylidenesorbitol, 1,3: 2,4-bis (p-ethylbenzylidene) sorbitol, 1,3: 2,4 -Bis (3,4-dimethylbenzylidene) sorbitol, triaminobenzene derivatives and the like are preferred. These may be used as a mixture of two or more.

  The blending ratio when the nucleating agent is added is preferably 0.001 to 1 part by weight, more preferably 0.005 to 0.8 part by weight, particularly 100 parts by weight of the propylene-based resin. Preferably it is a ratio of 0.01-0.6 weight part. If the blending amount of the nucleating agent is less than the above range, the transparency may be insufficient. On the other hand, if the blending amount exceeds the above range, the effect of imparting transparency will reach its peak, leading to a mere increase in cost.

4). Other Additives In the present invention, in addition to these essential components, additional components can be added as long as the effects of the present invention are not impaired. These additional components include antioxidants, light stabilizers, UV absorbers, lubricants, antistatic agents, antifogging agents, molecular weight modifiers (peroxides), colorants, neutralizing agents used in ordinary polypropylene. Agents, hydrotalcites, various auxiliary agents such as various fillers, propylene alone or copolymers with other α-olefins, other polymers such as low density polyethylene and high density polyethylene, various thermoplastic elastomers, etc. be able to.

[2] [Preparation of propylene-based resin composition]
The production method of the propylene-based resin composition used in the present invention is not particularly limited to the order of addition of the above components and the apparatus to be used, but generally used Henschel mixer, V blender, ribbon blender, Banbury mixer, kneader blender or extruder A method of mixing for a predetermined time using an ordinary mixer or kneader as described above and granulating with an ordinary extruder is preferred.
Also, the propylene resin composition used in the present invention is a so-called masterbatch method in which a nucleating agent is added in advance in a larger amount than the target compounding amount, and diluted to the target amount with the propylene resin before manufacturing the sheet. You can also take.

In the present invention, in order to recycle and use the antifogging sheet produced according to the present invention, the used antifogging sheet is pulverized by a pulverizer or the like, or the pulverized product is melt-kneaded. After making a regenerated pellet, it can be mixed with a virgin raw material to obtain a new propylene-based resin composition. At that time, the blending of the regenerated pellets is naturally limited in terms of discoloration that is expected to occur due to the fatty acid metal salt and sucrose fatty acid ester therein.
For the reasons described above, in the present invention, in the composition as a whole, the amount of the fatty acid metal salt is in the range of 0.005 to 0.04 parts by weight with respect to 100 parts by weight of the propylene-based resin. Then, it is necessary to make the application amount of the anti-fogging agent comprising sucrose fatty acid ester be in the range of 0.05 to ² g / m ² in terms of solid content.

[3] [Sheet and its manufacturing method]
1. Propylene-based resin sheet The thickness of the propylene-based resin sheet used in the present invention is 0.1 to 2 mm, preferably 0.15 to 1.5 mm, and particularly preferably 0.2 to 1 mm.
When the thickness is much less than 0.1 mm, the rigidity of the product is impaired, and when the thickness is much more than 2 mm, the transparency of the sheet is not sufficient.

  Moreover, as for the propylene-type resin sheet used for this invention, it is desirable for the haze value (HAZE value) of a 0.35 mm thickness sheet to be 20 or less. When the HAZE value is within this range, it can be suitably used for packaging foods that require transparency.

2. Sheet Forming The propylene-based resin sheet used in the present invention is obtained by extrusion sheet forming, calendar forming, or the like.
As extrusion sheet forming, the sheet is extruded from a coat hanger die through a single-screw or twin-screw extruder. The extruded sheet is pressed and solidified by cooling with an air knife, an air chamber, a hard rubber roll, a steel belt, a metal roll or the like on the surface of a metal roll through which cooling water or oil circulates, and is manufactured into a sheet. It is also possible to cool and solidify both sides of the sheet with a steel belt. Extrusion sheet molding can use a multilayer sheet in addition to a single layer. As a multilayer sheet, in addition to the propylene-based resin composition extruder of the present invention, a plurality of extruders are used, and a gas barrier resin layer, an adhesive resin layer, a recycled resin layer, and a decorative resin layer are used using a feed block and a multi-manifold. , Etc. can be made into a multilayer sheet.
Further, extruded sheet molding and calendered sheet can be processed into various containers and lid materials by thermoforming such as vacuum forming, vacuum pressure forming, hot platen pressure forming and the like.

[4] [Anti-fogging sheet and manufacturing method thereof]
1. Antifogging agent The antifogging agent used in the present invention is a sucrose fatty acid ester of a fatty acid having 6 to 22 carbon atoms, and this compound is recognized as an additive for foods and is most preferable from the viewpoint of safety.
Of these, sucrose fatty acid esters of stearic acid, palmitic acid, myristic acid, oleic acid, behenic acid, lauric acid and ericic acid are particularly preferred.
A commercial item can be used for the sucrose fatty acid ester used in the present invention. Commercially available products include “Ryoto Sugar Ester” (trade name) manufactured by Mitsubishi Chemical Foods Corporation.

The coating amount of the antifogging agent used in the present invention is 0.05 to ² g / m ² . If the coating amount is less than this range, the antifogging property of the sheet is insufficient. If the coating amount is more than this range, not only a further effect cannot be expected, but the sheet surface becomes sticky and the transparency is impaired.

2. Application method of anti-fogging agent When applying the anti-fogging agent to the propylene-based resin sheet used in the present invention, the sheet is subjected to oxidation treatment such as corona treatment, plasma treatment, flame treatment, etc. in advance. It is effective for stability. Among these, the sheet surface is preferably treated by corona treatment so that the wetting tension of the sheet surface is in the range of 35 to 55 dynes, preferably 36 to 45 dynes. If the wetting tension exceeds this range, an oxidized odor of the sheet is generated, which is not preferable. If the wetting tension is below this range, the adhesion of the antifogging agent to the sheet is impaired.

Application of the antifogging agent to the oxidized sheet is preferably performed by applying the antifogging agent as an antifogging agent solution of 0.01 to 10% by weight and then drying. As the solvent used in the antifogging agent solution, for example, a solution that dissolves the antifogging agent with water, alcohol, etc. and that does not dissolve the polypropylene resin sheet, and depending on the application field, appropriately select a solvent that satisfies safety. It is good to use. As an antifogging agent solid content to this sheet | seat, 0.05-2.0 g / m < ² > is apply | coated. When the coating amount of the antifogging agent is below this range, the antifogging performance is insufficient, and when the coating amount of the antifogging agent exceeds this range, blocking between the sheets due to stickiness is not preferable.
The above antifogging agent can be applied by any method such as various roll printing methods, soaking methods, and spraying methods. The coating method can be carried out by in-line coating performed after sheet forming or outline coating performed in a rewinding step after sheet forming / winding.
Examples of the drying method after applying the antifogging agent include a method of evaporating the solvent through a sheet through a drying furnace heated by steam or electricity (when the solvent is water, 100 ° C. or higher is preferable). There is no limit.

3. Anti-fogging sheet, etc. The anti-fogging polypropylene resin sheet of the present invention is extremely excellent in anti-fogging property, transparency and reusable use, so that it can be used for packaging products for food, cosmetics, daily necessities, electronic devices such as IC chips and liquid crystal panels. Most suitable for industrial parts such as parts packing trays and display boxes.
When reusing sheets and products, the sheets and products are pulverized and mixed with virgin raw materials, and then applied to a sheet molding machine. After pulverizing the sheets and products, they are melt-kneaded in an extruder and pellets (grains) The sheet is processed into a shape, mixed with the virgin raw material, and applied to a sheet forming machine.
In this case, although depending on the ratio of recycle use, the sheet forming process is more stable when the raw material is melt kneaded and processed into pellets (grains) because the bulk density of the raw material is more stable.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist. In addition, the measurement method, evaluation method, and material of the physical property values used in each example and comparative example are as follows.

I. Measurement method and evaluation method 1) MFR
MFR was measured based on JIS K7210 (230 degreeC, 2.16kg load).
2) Tensile elastic modulus Tensile elastic modulus was measured based on JIS K7127 after 1 day for a sheet having a thickness of 0.35 mm.
3) Haze value (HAZE value)
HAZE was measured on a sheet having a thickness of 0.35 mm in accordance with JIS K7136 one day after molding.

4) Ethylene content The ethylene content is a value measured by the ¹³ C-NMR method under the following conditions.
Apparatus: FT-NMR JEOL-GSX270 manufactured by JEOL Ltd.
Concentration: 300 mg / 2 mL
Solvent: Orthodichlorobenzene

5) Antifogging property The antifogging material application surface of the sheet was held over 80 ° C. hot water, and the state of water droplet adhesion was observed.
○: Water droplets do not adhere at all and can be seen well.
(Triangle | delta): A big water droplet is attached and 70% or more can be seen through.
X: A fine water droplet is attached and only 30% or less can be seen through.

6) Melt tension Melt tension was measured with a melt tension tester manufactured by Toyo Seiki Seisakusho.
Temperature: 190 ° C
Extrusion speed: 10mm / min
Take-up speed: 4m / min
Orifice: L / D = 8mm / 2.095mm

II. Material 1) Propylene resin The following propylene resin (A), propylene resin (B), propylene resin (C) and propylene resin (D) were used as the propylene resin.

(1) Production of propylene-based resin (A) In a gas phase fluidized bed reactor having an internal volume of 200 liters, ethylene, propylene, and hydrogen are respectively 0.31 vol%, 76.5 vol%, and 0.15 vol%. Propylene resin (A) which is a propylene homopolymer by supplying a solid catalyst component, a triethylaluminum solution, and an organosilicon compound under a continuously supplied condition, and performing polymerization at a polymerization temperature of 75 ° C. and a polymerization pressure of 3.0 MPaG. Got. The obtained propylene-based resin (A) was MFR = 1.4 g / 10 min.

(2) Production of propylene-based resin (B) Propylene-ethylene random copolymer was produced in a stirring polymerization tank having an internal volume of 200 liters. After sufficiently replacing the inside of the polymerization tank with propylene, 60 liters of dehydrated and deoxygenated n-heptane was introduced, and 30.0 g of diethylaluminum chloride and 10 g of Solvay type titanium trichloride catalyst were introduced at 60 ° C. in a propylene atmosphere. .
After raising the temperature in the polymerization tank to 60 ° C., propylene is introduced at a feed rate of 5.9 kg / hour and ethylene is introduced at a feed rate of 0.18 kg / hour. . %. After the polymerization was continued for 6 hours, the introduction of propylene and ethylene was stopped, and the temperature in the polymerization tank was further continued at 60 ° C. for 60 minutes.
The slurry thus obtained was filtered and dried to obtain 32.0 kg of a propylene-based resin (B) which is a powdery propylene-ethylene random copolymer. The obtained propylene-based resin (B) had MFR = 1.0 g / 10 min and ethylene content = 2.5% by weight.

(3) Propylene resin (C): Commercial product Propylene homopolymer manufactured by Nippon Polypro Co., Ltd. MFR = 1.4 g / 10 min.

(4) Propylene-based resin (D) production [catalyst production]
Into a 5 L separable flask equipped with a stirring blade and a reflux apparatus, 1,700 g of pure water was added, and 500 g of 98% sulfuric acid was added dropwise. Thereto, 300 g of montmorillonite granulated to an average particle size of 18 μm (product name “Benclay SL” manufactured by Mizusawa Chemical Industry Co., Ltd. was used as a raw material) was added and stirred. Thereafter, the mixture was reacted at 90 ° C. for 2 hours. This slurry was filtered and washed. To the collected cake, 1,230 g of a 27% lithium sulfate aqueous solution was added and reacted at 90 ° C. for 2 hours. This slurry was filtered and further washed until the pH of the filtrate reached 4 or higher. The recovered cake was pre-dried at 100 ° C. and then dried at 200 ° C. for 2 hours. As a result, 275 g of chemically treated montmorillonite was obtained.
To a 1 L flask, 20 g of chemically treated montmorillonite was added, 129 ml of heptane and 71 ml (50 mmol) of a heptane solution of triisobutylaluminum were added, and the mixture was stirred at room temperature for 1 hour. Thereafter, the residue was washed with heptane to a residual liquid ratio of 1/100, and finally the amount of slurry was adjusted to 100 ml. Furthermore, 3 ml (1 mmol) of a heptane solution of trinormal octyl aluminum was added and stirred at room temperature for 10 minutes.
In a 200 ml flask, heptane (50 ml) was added to (r) -dimethylsilylenebis [1,1 ′-{2-methyl-4- (4-chlorophenyl) -4H-azurenyl}] hafnium (300 μmol) to form a slurry. Then, in addition to the 1 L flask, the mixture was stirred at room temperature for 60 minutes. Thereafter, 181 ml of heptane was added to prepare a catalyst slurry.

[Preliminary polymerization]
The entire amount of the catalyst slurry was introduced into a stirring autoclave having an internal volume of 1.0 L that had been sufficiently replaced with nitrogen. When the temperature was stabilized at 40 ° C., propylene was supplied at a rate of 10 g / hour to maintain the temperature. After 4 hours, the supply of proprene was stopped and maintained for another hour. After completion of the prepolymerization, the residual monomer was purged, the stirring was stopped, and the slurry was extracted into a 1 L flask that had been sufficiently purged with nitrogen. This slurry was dried under reduced pressure to recover 63.4 g of a prepolymerized catalyst.

[polymerization]
After sufficiently replacing the interior of the autoclave with an induction stirrer with an internal volume of 200 L with propylene, 45 kg of sufficiently dehydrated liquefied propylene was introduced and maintained at 30 ° C. To this, 470 ml (50 g / l) of a heptane solution of triisobutylaluminum was added. Hydrogen 2.0NL and ethylene 0.9kg were introduced, and 1.7g of the prepolymerized catalyst was injected with argon. The temperature was raised to 65 ° C. over 40 minutes, and the reaction was carried out at 65 ° C. for 2 hours. During this time, hydrogen was introduced at a constant speed of 0.12 g / hr. Thereafter, 100 ml of ethanol was injected to stop the reaction, and the remaining gas was purged. As a result, 18.4 kg of propylene-based resin (D) was obtained. The resin had an MFR of 1.4 g / 10 min and an ethylene content of 1.3% by weight.

2) Fatty acid metal salt The following compounds were used as fatty acid metal salts.
(1) Calcium stearate (2) Aluminum stearate: trade name “Al-ST (103)” manufactured by Nitto Kasei Kogyo Co., Ltd.

3) Nucleating agent The following compounds were used as the nucleating agent.
(1) Product name “Adeka Stub NA-11” manufactured by ADEKA
Phosphoric acid 2,2′-methylenebis (4,6-di-t-butylphenyl) sodium salt nucleating agent (2) “ADEKA STAB NA-21” manufactured by ADEKA
Phosphate-2,2′-methylenebis (4,6-di-tert-butylphenyl) aluminum salt nucleating agent (3) “ADEKA STAB NA-71” manufactured by ADEKA
Phosphate-2,2′-methylenebis (4,6-di-tert-butylphenyl) lithium salt nucleating agent

4) Antifogging agent The following compounds were used as an antifogging agent.
(1) Ryoto sugar ester LWA-1570: Sucrose laurate (manufactured by Mitsubishi Chemical Foods)

[Example 1]
1-1) Preparation of composition With respect to 100 parts by weight of the propylene-based resin (A), 0.01 part by weight of calcium stearate as a fatty acid metal salt, and [tetrakis (3,5-di-t-butylphenylpropylene as an antioxidant) ONATE)] 0.03 part by weight of methane (trade name: “Irganox RA1010” manufactured by Ciba Specialty Chemicals Co., Ltd.) and Tris (dibutylphenyl) phosphite (trade name: “Irgaphos manufactured by Ciba Specialty Chemicals Co., Ltd.) 168 ") 0.1 part by weight was added and mixed with a Henschel mixer to obtain a propylene-based resin composition, which was then extruded into a granulated product by an extruder having a screw diameter of 50 mm heated to 260 ° C.

1-2) Production of Extruded Sheet The obtained granular material was extruded in a horizontal direction from a coat hanger die having a width of 750 mm and a die lip interval of 0.8 mm in an extrusion sheet molding machine heated to 230 ° C. and having a screw diameter of 40 mm, and 30 ° C. The sheet was cooled and solidified with a mirror-finished hard chrome-plated metal roll in which water was circulated, and a sheet having a thickness of 0.35 mm was manufactured while corona treatment was applied to one side to make 40 dynes. Table 1 shows the measurement results of the physical properties of the obtained sheet.

1-3) Application of antifogging agent Next, a 50 times aqueous solution of Ryoto Sugar Ester LWA-1570 (sucrose laurate) manufactured by Mitsubishi Chemical Foods Co., Ltd. was applied to the corona-treated surface of the above sheet with a gravure coater. No. ² was applied, dried with a drier in which air at 120 ° C. was circulated, and wound up with a winder to prepare an antifogging sheet. The antifogging agent solid content is a coating amount of 0.08 g / m ² . Five of these anti-fogging sheets were stacked and the YI value was measured with a color machine manufactured by Nippon Denshoku. The results are shown in Table 1.

1-4) Production of Recycled Pellet Then, the above antifogging sheet was applied to a φ9 mm screen with a crusher UI03-30120MRFS manufactured by Horai Co., Ltd. to obtain a pulverized product. This pulverized product was melt-kneaded with an extruder having a screw diameter of 40 mm heated to 230 ° C. to produce recycled pellets.

1-5) Production of Recycled Sheet 50 parts by weight of the granulated material of 1-1) is mixed with 50 parts by weight of the regenerated pellets of 1-4), and regenerated antifog by the method of 1-1) to 1-3) Created a sheet. Five of these anti-fogging sheets were stacked and the YI value was measured with a color machine manufactured by Nippon Denshoku. The results are shown in Table 1.

[Example 2]
For 100 parts by weight of the propylene-based resin (B), 0.01 part by weight of calcium stearate as a fatty acid metal salt and 2,2′-methylenebis (4,6-di-t-butylphenyl) sodium phosphate as a nucleating agent ( "ADK STAB NA-11") 0.1 parts by weight, and further [Tetrakis (3,5-di-t-butylphenylpropionate)] methane 0.03 parts by weight ("Irganox RA1010") and Tris as an antioxidant (Dibutylphenyl) phosphite ("Irgaphos 168") 0.1 part by weight was added and mixed in a Henschel mixer to obtain a propylene-based resin composition, and then an extruder having a screw diameter of 50 mm heated to 260 ° C. Extruded granules were obtained.
Thereafter, the same method as in 1-3) to 1-5) of Example 1 was applied to the granular material to prepare a regenerated antifogging sheet. The results are shown in Table 1.

[Example 3]
In Example 1, the amount of calcium stearate used was reduced from 0.01 parts by weight to 0.007 parts by weight, and DHT-4A (hydrotalcite compound, trade name, manufactured by Kyowa Chemical Industry Co., Ltd.) was used as a Ziegler catalyst scavenger. A recycled antifogging sheet was prepared by applying the same method as in 1-1) to 1-5) of Example 1 except that 0.02 part by weight was blended. The results are shown in Table 1.

[Comparative Example 1]
Evaluation was performed in the same manner as in Example 1 except that the composition of the propylene-based resin composition was changed as shown in Table 2. The results are shown in Table 2.

[Comparative Example 2]
Evaluation was performed in the same manner as in Example 1 except that the propylene resin composition was changed to the trade name “Novatec PP EA7A” manufactured by Nippon Polypro Co., Ltd., which is the following commercial grade, and the formulation was as shown in Table 2. The results are shown in Table 2.
"Novatech PP EA7A" is 0.05 parts by weight of "Irganox RA1010", 0.1 parts by weight of "Irgaphos 168" and 0.05 parts of calcium stearate with respect to 100 parts by weight of the propylene-based resin (C). Part by weight is added.

[Comparative Example 3]
Evaluation was made in the same manner as in Comparative Example 3 except that the antifogging agent was not applied in Comparative Example 2. The results are shown in Table 2.

[Comparative Example 4]
0.01 parts by weight of calcium stearate as a fatty acid metal salt, and [tetrakis (3,5-di-t-butylphenylpropionate)] methane 0.03 as an antioxidant with respect to 100 parts by weight of the propylene-based resin (D) After adding 0.1 part by weight of “Irganox RA1010” and 0.1 part by weight of tris (dibutylphenyl) phosphite (“Irgaphos 168”) and mixing with a Henschel mixer to obtain a propylene-based resin composition, 260 Extruded granules were obtained with an extruder having a screw diameter of 50 mm heated to ° C.
Thereafter, the same method as in 1-3) to 1-5) of Example 1 was applied to the granular material to prepare a regenerated antifogging sheet. The results are shown in Table 2.

[Examples 4 to 6]
Example 1 was carried out in the same manner as in Example 1 except that the formulation was changed as shown in Table 3. The results are shown in Table 3.

As is clear from these results, in Examples 1 to 6, the propylene-based antifogging sheet of the present invention has a small HAZE value (excellent transparency), excellent antifogging properties, and changes in hue even when reproduced. I understand that there are few things.
On the other hand, in Comparative Examples 1 and 2, since the amount of the fatty acid metal salt specified in the present application exceeded, the hue of the recycled sheet was extremely bad. In Comparative Example 3, although the amount of the fatty acid metal salt specified in the present application exceeds, the hue change of the recycled sheet is small because no antifogging agent is applied, but there is no antifogging performance. In Comparative Example 4, a propylene-based resin obtained using a catalyst different from the present application was used, which was inferior in terms of melt tension and inferior in moldability.

  From the data of each of the above examples and the comparison result with each comparative example, the antifogging propylene-based resin sheet of the present invention has better transparency and antifogging properties than conventional materials, and even when reproduced, the hue. It is clear that there is little change, the rationality and significance of the requirements that make up the present invention are demonstrated, and the superiority to the prior art is also revealed.

  As described above, according to the present invention, an antifogging propylene-based resin sheet that is excellent in transparency and antifogging properties and has little discoloration even after being recycled can be obtained. It can be suitably used in the field of food daily necessities packaging and medical electronic parts, and its industrial utility is very high.

Claims (4)

A propylene-based resin sheet obtained by applying an antifogging agent having a solid content of 0.05 to ² g / m ^{2 on} at least one surface of a propylene-based resin sheet having a thickness of 0.1 to ² mm,
The propylene-based resin sheet has a fatty acid of 6 to 22 carbon atoms, calcium, sodium, zinc and lithium with respect to 100 parts by weight of a propylene-based resin having an MFR of 0.3 to 20 g / 10 min obtained using a Ziegler-based catalyst. , Formed from a propylene-based resin composition formed by blending at least one fatty acid metal salt with a metal selected from aluminum or magnesium in a proportion of 0.005 to 0.04 parts by weight,
On the other hand, the said antifogging agent consists of sucrose fatty acid ester of a C6-C22 fatty acid, The antifogging propylene-type resin sheet characterized by the above-mentioned.   The anti-fogging propylene resin sheet according to claim 1, wherein the propylene resin is a random copolymer having a propylene content of 100 to 90% by weight and an α-olefin content of 0 to 10% by weight.   The anti-fogging propylene resin sheet according to claim 2, wherein the α-olefin is ethylene.   The haze value (HAZE value) of a 0.35 mm thick sheet is 20 or less, The antifogging propylene-based resin sheet according to any one of claims 1 to 3.