JP2006183221A - Oil resistant paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide oil-resistant paper safe and friendly to the environment, and suitably usable as food packaging paper or the like. <P>SOLUTION: The oil-resistant paper is such that at least one side of a paper substrate is borne with an oil-resistant layer comprising a hydrogen-bonding resin and oil-absorbing particles. Specifically, the oil-absorbing particles are starch particles. Further specifically, the hydrogen-bonding resin is polyvinyl alcohol. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides an oil-resistant paper excellent in oil resistance for packaging articles and foods containing a large amount of oil components.

When packaging articles and foods rich in oil components such as chocolate and hamburgers, fried pork cutlet, mentaka cutlet, tempura, etc., they are often wrapped in oil-resistant paper or paperboard.
The paper used for the packaging as described above needs to have oil resistance so that oil in articles and foods is repelled and oil does not ooze out on the surface not in contact with food.

As a method for imparting oil resistance to a paper material, a nonionic or cationic polyvinyl alcohol coating layer and a fluorine-based oilproofing agent coating layer are provided on at least one side of an internally added size paper of single-layer papermaking. The use of oil-resistant paper provided sequentially has been proposed (see Patent Document 1).
Moreover, the food heating packaging paper which has a polyvinyl alcohol layer and a silicone resin layer as what does not use a fluorine compound is proposed (refer patent document 2).

Patent Document 3 proposes a water / oil repellent composition comprising a specific fluorine copolymer, a non-fluorine surfactant, a medium and a specific water-soluble polymer as essential components.
Patent Document 4 discloses a coating layer of nonionic or cationic polyvinyl alcohol on at least one surface of an internally-added size paper that is a single-layer paper having a Cobb water absorption of 100 g / m ² or less, and a fluorine-based oilproofing agent. Oil-resistant paper has been proposed in which coating layers are sequentially provided.
Patent Document 5 uses wood pulp containing a saponification degree of 85 to 100% and an average polymerization degree of 500 to 2500 with a crosslinking agent added, and an aspen material containing 30% by weight or more. There has been proposed an oil-resistant paper in which a processing layer of 1 to 8 g / m ² is provided on at least one side of a main base paper.

Patent Document 6 is characterized in that an oil-resistant coated paper in which an oil-resistant coating layer and a clay coating layer are sequentially applied to the outer surface of the paper base material, and is boxed with the inner surface of the oil-resistant coated paper inside. An oil-resistant paper container having an oil absorbing function is proposed.
Patent Document 7 proposes an oil- and water-resistant sheet having a coating layer containing at least polyvinyl alcohol and shellac (shellac) on at least one surface of a base sheet.
Patent Document 8 proposes an oil- and water-resistant sheet having a coating layer containing at least polyvinyl alcohol cured with an isocyanate compound on at least one surface of a base sheet.
Patent Document 8 proposes an oil and water resistant sheet having a coating layer containing at least polyvinyl alcohol and silicone oil on at least one surface of a base sheet.

JP-A-7-12849 JP-A-8-232194 Patent Publication WO2002 / 031261 JP 08-209590 A Japanese Unexamined Patent Publication No. 2004-68180 JP 2004-217296 A JP 2004-256926 A JP 2004-270049 A JP 2004-270050 A

Among the background art described above, oil-resistant paper using an oil-resistant agent containing a fluorine-based compound is said to generate fluorine compounds such as hydrogen fluoride, carbonyl fluoride, and hydrofluoric acid from the oil-resistant agent under high temperature conditions. When oil-resistant paper is used for food packaging, a toxic fluorine compound may be generated during cooking, or after being discarded after being used and incinerated, which is problematic in terms of safety.
In addition, laminated paper coated and impregnated with a polyvinyl alcohol compound improves water resistance, and the current situation is that the improvement in oil resistance is still insufficient.
An object of the present invention is to provide an oil-resistant paper that can be used for a food wrapping paper that is safe and environmentally friendly and has oil resistance.

The present invention adopts the following method in order to solve the above problems.
That is, the first of the present invention is an oil-resistant paper having an oil-resistant layer containing a hydrogen bonding resin and oil-absorbing particles on at least one surface of the paper support.

  A second aspect of the present invention is the oil-resistant paper according to the first aspect of the present invention, wherein the oil-absorbing particles are starch particles.

  3rd of this invention is the oil-resistant paper in any one of 1-2 of this invention whose hydrogen bond resin is polyvinyl alcohol.

  According to the present invention, it is possible to provide an oil-resistant paper excellent in oil resistance.

Hereinafter, the present invention will be described in detail.
In particular, the inventors of the present invention further studied to impart oil resistance to a laminate such as paperboard provided with a hydrogen bonding resin layer such as polyvinyl alcohol resin.
First, hydrophobic resins such as paraffin wax, silicone resin, and acrylic styrene resin were added to polyvinyl alcohol (hereinafter referred to as PVA) to study the improvement in oil resistance.
However, it has been found that the PVA layer in which the above resin layer contains oil-absorbing particles, particularly starch particles not gelatinized, exhibits very high oil resistance. The reason for this is thought to be that the starch particles selectively take in the oil and prevent the oil from penetrating into the paper substrate. This is supported by the fact that the oil resistance of the PVA layer containing gelatinized starch is not improved.

The oil-absorbing particles in the present invention refer to those having an oil absorption amount measured by JIS K-5101 of 10 ml / 100 g or more, and the type is not particularly limited as long as this condition is satisfied. If the oil absorption is less than 10 ml / 100 g, the oil absorption is insufficient and sufficient oil resistance cannot be imparted.
Further, as the oil-absorbing particles satisfying the above conditions, silica, calcium carbonate, calcined clay, kaolin and the like can be used as inorganic particles, and polysaccharide particles, polystyrene particles, acrylic particles and the like as organic particles. Of these, silica and polysaccharides can be suitably used because of their excellent oil absorption. Among the polysaccharide particles, starch particles are particularly preferred because they are most excellent in oil absorption and dispersibility in a hydrogen bonding resin.

In the present invention, the polysaccharide is a biopolymer synthesized in a biological system by condensation polymerization of various monosaccharides, and includes those chemically modified based on them.
For example, cellulose and cellulose derivatives such as hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, amylose, amylopectin, pullulan, curdlan, xanthan, chitin, chitosan, starch and the like can be mentioned.

As the polysaccharide used as the oil-absorbing particles in the present invention, starch (starch) can be suitably used. Starch particles not only have excellent oil absorbability, but also have excellent dispersibility in aqueous solutions of hydrogen bonding resins.
The starch (starch) used in the present invention may be, for example, corn starch, wheat starch, sago starch, ground starch such as rice starch, tapioca starch, potato starch, or underground starch such as sweet potato starch, but stable. From the viewpoint of supply and economy, corn starch, wheat starch and tapioca starch are advantageous.
If necessary, modified products such as enzyme modified, thermochemical modified, acetate ester modified, phosphate ester modified, carboxy ether modified, hydroxy ether modified, cation modified may be used. It is.

The average particle diameter of the oil-absorbing particles used in the present invention is a value measured in a particle size distribution measuring apparatus by laser diffraction applying a light scattering theory to a water dispersion of oil-absorbing particles, and is in the range of 0.1 to 100 μm. More preferably, it is 1.0-50 micrometers, Most preferably, it is 3.0-20 micrometers.
When the average particle size is less than 0.1 μm, it is difficult to classify the oil-absorbing particles into a uniform particle size, which not only increases the cost but also improves the oil resistance effect, which is not preferable. On the other hand, when the average particle size exceeds 100 μm, the oil-resistant layer is likely to be lost and as a result, the oil resistance may be deteriorated.

The hydrogen bonding resin that can be used in the present invention has a hydrogen bonding group or an ionic group in the resin. Although it will not be restrict | limited especially if it is resin which satisfy | fills this condition, The thing whose solubility in a pure water (23 degreeC) is 1 mass g / 100 mass g water or more is preferable.
The hydrogen bonding resin preferably has a mass percentage of hydrogen bonding groups or ionic groups per unit mass of the resin of 20 to 60%, more preferably 30 to 50%.
Examples of the hydrogen bonding group of the hydrogen bonding resin include a hydroxyl group, an amino group, a thiol group, a carboxyl group, a sulfonic acid group, and a phosphoric acid group, and the ionic group includes a carboxylate group and a sulfonic acid ion group. , Phosphate ion group, ammonium group, phosphonium group and the like. Of these hydrogen bonding groups or ionic groups, preferred are hydroxyl group, amino group, carboxyl group, sulfonic acid group, carboxylate group, sulfonic acid ion group, ammonium group and the like.

  Specific examples of the hydrogen bonding resin include, for example, polyvinyl alcohol, an ethylene-vinyl alcohol copolymer having a vinyl alcohol fraction of 41 mol% or more, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, amylose, amylopectin, pullulan, curdlan. , Polysaccharides such as xanthan, chitin, chitosan, cellulose, polyacrylic acid, sodium polyacrylate, polybenzenesulfonic acid, sodium polybenzenesulfonate, polyethyleneimine, polyallylamine, its ammonium salt polyvinylthiol, polyglycerin, etc. Is mentioned.

More preferable examples of the hydrogen bonding resin include polyvinyl alcohol and ethylene-vinyl alcohol copolymer.
Polyvinyl alcohol (hereinafter referred to as PVA) is a polymer having a vinyl alcohol monomer unit as a main component. As such PVA, for example, a polymer obtained by hydrolysis or transesterification (saponification) of an acetate portion of a vinyl acetate polymer (exactly a copolymer of vinyl alcohol and vinyl acetate) or , A polymer obtained by saponifying a vinyl trifluoroacetate polymer, a vinyl formate polymer, a vinyl pivalate polymer, a t-butyl vinyl ether polymer, a trimethylsilyl vinyl ether polymer, or the like.

The degree of saponification in the PVA used in the present invention is preferably 70% or more, more preferably 85% or more, and more preferably 98% or more of a so-called fully saponified product. The degree of polymerization is preferably 100 to 5000 or less, and more preferably 200 to 3000.
The PVA may be modified with a functional group such as a silanol group (—Si (OH) ₃ ), an amino group, or a carboxylic acid as necessary.

In the present invention, the content of the oil-absorbing particles is 5 to 90% by mass in terms of mass to solid content with respect to the hydrogen bonding resin. More preferably, it is 10-90 mass%, Most preferably, it is 20-90 mass%.
When the oil-absorbing particles are less than 5% by mass, it is difficult to obtain the effect of improving oil resistance by the oil-absorbing particles, which is not preferable. On the other hand, if it exceeds 90% by mass, pinholes are likely to be formed in the oil-resistant layer, and the oil resistance may be lowered.

In the present invention, a hydrogen bonding group crosslinking agent can be used for the purpose of improving the water resistance of the hydrogen bonding resin.
Examples of the hydrogen bonding group crosslinking agent include titanium coupling agents, silane coupling agents, copper compounds, zirconium compounds, boron compounds, colloidal silica, and the like. Among these, a zirconium compound, a silane coupling agent, and a boron compound can be preferably used.

  Zirconium compounds that can be used as a crosslinking agent include zirconium halides such as zirconium oxychloride, hydroxyzirconium chloride, zirconium tetrachloride and zirconium bromide, zirconium salts of mineral acids such as zirconium sulfate, basic zirconium sulfate and zirconium nitrate, Zirconium salts of organic acids such as zirconium formate, zirconium acetate, zirconium propionate, zirconium caprylate, zirconium stearate, ammonium zirconium carbonate, sodium zirconium sulfate, ammonium zirconium acetate, sodium zirconium oxalate, sodium zirconium citrate, zirconium ammonium citrate Zirconium complex salts such as

Examples of silane coupling agents that can be used as crosslinking agents include vinyltrimethoxysilane, vinyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane. , Γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxy Examples thereof include silanephenyl triethoxysilane, γ-fluoropropyltrimethoxysilane, and N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane. Among these, amino group-containing silane coupling agents can be preferably used.
The silane coupling agent also has an effect of hydrophobizing the surface of the polysaccharide oil-absorbing particles. By hydrophobizing the particle surface of the polysaccharide, the oil resistance and water resistance of the oil resistant layer in the present invention are improved.
Examples of boron compounds that can be used as a crosslinking agent include boron oxide, ammonium tetraborate, sodium tetraborate, boric acid, and anhydrous boric acid.

In order to improve the oil resistance and water resistance of the oil resistant layer of the present invention, an inorganic layered compound can be further added to the oil resistant layer.
As the inorganic layered compound to be used, natural mica, synthetic mica, clay minerals such as smectite and montmorillonite, and synthetic smectite are preferable.
The particle size of the inorganic layered compound is preferably 10 nm to 100 μm, and the thickness is preferably 1 nm to 1 μm. Among inorganic layered compounds, water-swellable inorganic layered compounds are more preferably used because they have a strong interaction with the hydrogen bonding resin and are excellent in oil resistance and water resistance.

As the paper base material constituting the oil-resistant paper of the present invention, high-quality paper having a basis weight of about 30 to 500 g / m ² , glassine paper, unbleached kraft paper, bleached kraft paper, coated paper, paperboard, white paperboard and Manila A ball or the like is preferable.

The present invention will be specifically described below with reference to examples.
Unless otherwise specified, parts in the examples represent parts by mass.
<Example 1>
To 100 parts by mass of water, 5 parts of starch particles (trade name: Ace K100, average particle size 10 μm, manufactured by Oji Cornstarch Co., Ltd.) were added with stirring to obtain an aqueous dispersion of starch particles.
To 50 parts of the obtained aqueous dispersion, 100 parts of an aqueous solution (5% as solid content) of PVA (trade name: PVA105, degree of saponification 98.5%, degree of polymerization 500, manufactured by Kuraray Co., Ltd.) was stirred. Then, an oil resistant paint was obtained. In addition, preparation of the coating material was performed while always maintaining the temperature of the coating material at 20 ° C. so that the starch particles would not be gelatinized.
The oil-resistant paint obtained above was coated on the non-coated surface of white paperboard (basis weight 250 g / m ² , MC ball (f) 250) with a Mayer bar so that the solid content was 2 g / m ² . Then, it dried at 110 degreeC for 1 minute using the hot air dryer, and obtained oil-resistant paper.

<Example 2>
An oil-resistant paper was obtained in the same manner as in Example 1 except that the amount of the starch particle aqueous dispersion added was 10 parts.

<Example 3>
An oil-resistant paper was obtained in the same manner as in Example 1 except that the amount of the starch particle aqueous dispersion added was 150 parts.

<Example 4>
To 100 parts by mass of water, 5 parts of starch particles having an average particle diameter of 10 μm (trade name: Ace K100, average particle diameter of 10 μm, manufactured by Oji Cornstarch Co., Ltd.) are added with stirring to obtain an aqueous dispersion of starch particles. It was.
After adding 1 part by mass of a hydrolyzed aqueous solution of an aminosilane coupling agent to 50 parts by mass of the obtained aqueous dispersion and stirring, silyl group-modified PVA (trade name: PVA105, saponification degree 98.5%, polymerization) 100 parts of an aqueous solution (5% as a solid content) having a degree of 500, manufactured by Kuraray Co., Ltd. was added with stirring, and further 3 parts of an aqueous solution of boron oxide was added and stirred to obtain an oil-resistant paint. In addition, preparation of the coating material was performed while always maintaining the temperature of the coating material at 20 ° C. so that the starch particles would not be gelatinized.
The oil-resistant paint obtained above was coated on the non-coated surface of white paperboard (basis weight 250 g / m ² , MC ball (f) 250) with a Mayer bar so that the solid content was 2 g / m ² . Then, it dried at 110 degreeC for 1 minute using the hot air dryer, and obtained oil-resistant paper.

<Example 5>
An oil-resistant paper was obtained in the same manner as in Example 1 except that silica particles (trade name: Silojet P416, average particle size 12.0 μm, manufactured by Grace Devison Co., Ltd.) were used instead of starch particles.

<Comparative Example 1>
An aqueous solution of PVA (trade name: PVA105, degree of saponification of 98.5%, degree of polymerization of 500, manufactured by Kuraray Co., Ltd.) (5% as solid content) so that it may be ² g / m ² in terms of solid content. After coating on the non-coated surface of white paperboard (basis weight 250 g / m ² , MC ball (f) 250), it was dried at 110 ° C. for 1 minute using a hot air dryer to obtain oil-resistant paper.

<Comparative example 2>
To 100 parts by mass of water, 5 parts of starch particles (trade name: Ace K100, average particle size 10 μm, manufactured by Oji Corn Starch Co., Ltd.) were added and stirred at 100 ° C. for 1 hour to obtain a gelatinized starch aqueous solution. .
To 50 parts by mass of the obtained gelatinized starch aqueous solution, 100 parts of an aqueous solution (5% as solid content) of PVA (trade name: PVA105, saponification degree 98.5%, polymerization degree 500, manufactured by Kuraray Co., Ltd.) The mixture was added with stirring to obtain an oil resistant paint.
The obtained oil-resistant paint is coated on a paperboard (basis weight 250 g / m ² ) with a Mayer bar so that the solid content is 2 g / m ^2, and then dried at 110 ° C. for 1 minute using a hot air dryer. As a result, oil-resistant paper was obtained.

<Comparative Example 3>
To 100 parts by mass of water, 5 parts of starch particles (trade name: Ace K100, average particle size 10 μm, manufactured by Oji Cornstarch Co., Ltd.) were added with stirring to obtain an oil resistant paint. The paint preparation was always carried out with the temperature of the paint kept at 20 ° C. so that the starch did not gelatinize.
The obtained oil-resistant paint is coated on a paperboard (basis weight 250 g / m ² ) with a Mayer bar so that the solid content is 2 g / m ^2, and then dried at 110 ° C. for 1 minute using a hot air dryer. As a result, oil-resistant paper was obtained.

<Test method>
(1) Tempura (a black tiger with a shell length of about 150 mm) is sprinkled with a garment solution (about 20 g) prepared by adding 540 cc of water and egg yolk to 360 g of flour, and about 180 ° C. with commercially available corn oil. (2 minutes heating) was placed directly on the oil-resistant layer of the oil-resistant paper, and the presence or absence of oil stain on the surface of the oil-resistant layer after 3 hours and the state thereof were visually determined.
(2) A commercially available chocolate with almonds (5 spherical chocolates with a diameter of about 20 mm) is placed directly on the oil-resistant layer of oil-resistant paper, and after a week at 23 ° C. and 50%, the oil stain on the surface of the oil-resistant layer Presence / absence and state were visually determined.

Claims (3)

An oil-resistant paper comprising an oil-resistant layer containing a hydrogen bonding resin and oil-absorbing particles on at least one surface of a paper support. The oil-resistant paper according to claim 1, wherein the oil-absorbing particles are starch particles. The oil-resistant paper according to claim 1, wherein the hydrogen bonding resin is polyvinyl alcohol.