JP2021088787A - Multilayer paper for beverage and food - Google Patents

Abstract

To provide a multilayer paper for beverage and food having excellent food sanitation.SOLUTION: A multilayer paper for beverage and food includes a plurality of paper layers and, in interlayers thereof, a starch-based adhesive, wherein a bacterial count in the paper is 250/g or under.SELECTED DRAWING: None

Description

The present invention relates to a multilayer paper for food and drink.

The slurry (aqueous dispersion) for making paper contains nutrient sources such as pulp and additives, and is an environment suitable for the growth of microorganisms. When microorganisms grow in the slurry, a biofilm called slime is formed, and deterioration of quality due to contamination of foreign substances derived from this slime becomes a problem. Slime control agents and bactericidal agents are used to suppress the growth of microorganisms in the slurry (Patent Documents 1 and 2).

Very high food hygiene standards are required for food and drink paper that comes into contact with food and drink, and for example, the number of bacteria in the paper is required to be a certain number or less. Food and beverage paper is made using the above-mentioned slime control agent and bactericide at a high concentration, but it is difficult to reduce the number of bacteria in the paper to zero, and microorganisms are mixed in although it is below the standard value. It may end up.

When the present inventors investigated food and drink paper containing microorganisms, most of the mixed microorganisms were spore-forming bacteria. The spore-forming bacterium becomes dormant by becoming a spore under high stress, and when the environment suitable for growth is reached, the spore-forming bacterium germinates from the spore and resumes its activity. Spore-forming spore-forming bacteria are excellent in chemical resistance, heat resistance, etc., and can survive in a harsh environment. It is considered that the spore-forming bacteria, by becoming spores, withstood exposure to bactericides and the like in the papermaking process and high heat during drying, and were mixed in food and drink paper.

As a result of further investigation, it was found that spore-forming bacteria were abundantly inhabited in the aqueous dispersion of the interlayer starch at the time of bonding. Since spore-forming bacteria are widely distributed in soil, they adhere to raw materials such as corn, potatoes, and cassava. They survive the process of processing these raw materials into starch for papermaking in the spore state and are mixed in the interlayer starch. It is presumed that it was done. On the other hand, at the time of papermaking, inner starch and outer starch were also used, but spore-forming bacteria did not inhabit the aqueous dispersion of the inner starch and the outer starch. This is because the inner starch and the outer starch are made into a paste by the steaming process. In this steaming process, the spore-forming bacteria were also sterilized by being exposed to a high temperature of about 130 ° C. It is presumed that this is because there is no step such as a step that can sterilize spore-forming bacteria.

JP-A-2002-294591 Japanese Unexamined Patent Publication No. 2014-176801

An object of the present invention is to provide a multilayer paper for food and drink having excellent food hygiene.

The means for solving the problem of the present invention is as follows.
1. 1. It has a plurality of paper layers and a starch-based adhesive between the layers.
A multi-layer paper for food and drink, characterized in that the number of bacteria in the paper is 250 cells / g or less.
2. The starch-based adhesive is characterized by containing modified starch processed by a dry method. Multi-layer paper for food and drink described in.
3. 3. The starch-based adhesive is characterized by containing one or more of urea phosphorylated ester starch, phosphate esterified starch, dry low molecular weight hydroxyethylated starch, and roasted dextrin. Or 2. Multi-layer paper for food and drink described in.

The multi-layer paper for food and drink of the present invention is excellent in food hygiene because the number of bacteria in the paper is small even though a starch-based adhesive is used. Modified starch processed by the dry method reduces spore bacteria when heated by the dry method, so even if it is used as an interlayer adhesive for multi-layer paper for food and drink, the number of microorganisms mixed in the paper can be suppressed. it can.

-Multilayer Paper for Foods The present invention relates to a multilayer paper for foods and drinks, which has a plurality of paper layers and a starch-based adhesive between the layers, and the number of bacteria in the paper is 250 cells / g or less.
In the multi-layer paper for food and drink of the present invention, the number of bacteria in the paper is preferably 200 cells / g or less, more preferably 150 cells / g or less, and further preferably 100 cells / g or less. preferable.

In the present invention, the number of bacteria in paper is a value measured by the following method with reference to "Food Sanitation Inspection Guideline-Microorganisms-" supervised by the Ministry of Health, Labor and Welfare.
1. 1. The portion of the food and drink paper other than the outer edge of 5 cm is cut into 0.5 cm squares, and a sample of 0.3 to 0.5 g is collected and weighed precisely.
2. Phosphate buffer (pH 7.2) is added so that the sample becomes 1% by weight, and the pulp is sufficiently stirred using a homogenizer until the pulp is dissociated, and then heated at 100 ° C. for 10 minutes to cause bacteria other than heat-resistant spore-forming bacteria. Is sterilized to obtain a sample stock solution.
3. 3. 1 ml of the obtained stock solution of the sample is dispensed into a petri dish having 9 ml of a standard agar medium prepared and sterilized in advance, and allowed to stand at 32 ° C. for 48 hours.
4. After standing, the number of colonies expressed on the petri dish is defined as the number of bacteria, and the number of bacteria in paper (pieces / g) is determined from the dilution ratio and the weight of the finely weighed sample.

<Paper layer>
In the present invention, the paper layer is a sheet made of pulp, filler, various auxiliaries and the like.
As the pulp, chemical pulp of wood such as bleached kraft pulp of coniferous tree (NBKP), unbleached kraft pulp (NUKP), bleached kraft pulp of broadleaf tree (LBKP), unbleached kraft pulp (LUKP), sulfite pulp (SP) , Grand pulp (GP), refiner ground pulp (RGP), stone ground pulp (SGP), chemi-grand pulp (CGP), semi-chemical pulp (SCP), thermomechanical pulp (TMP), chemi-thermomechanical pulp (CTMP) Machine pulp of wood such as, Kenaf, Bagus, non-wood pulp obtained from bamboo, hemp, straw, etc., used paper pulp from which the ink contained in these used papers has been removed by the deinking process, etc. Pulp can be appropriately blended and used. Among these, chemical pulps such as LBKP and NBKP, which are less likely to be mixed with foreign substances, are preferable, and the amount of used paper pulp is preferably small. Specifically, the blending amount of the chemical pulp with respect to the total amount of pulp is preferably 80% by weight or more, more preferably 90% by weight or more, and most preferably 100% by weight.

Fillers include talc, kaolin, calcined kaolin, clay, heavy calcium carbonate, light calcium carbonate, white carbon, zeolite, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, and aluminum hydroxide. , Use known fillers such as inorganic fillers such as calcium hydroxide, magnesium hydroxide, zinc hydroxide, barium carbonate, calcium sulfate, and organic fillers such as urea-formalin resin, polystyrene resin, phenol resin, and fine hollow particles. Can be done. In the laminated body of the present invention, the paper layer does not have to use a filler, and it is preferable not to use a filler.

As various auxiliaries, various internal sizing agents such as rosin, alkyl ketene dimer (AKD), alkenyl succinic acid anhydride (ASA), various nonionic, cationic and amphoteric yield improvers, and drainage level improvers. , Paper strength improver, various starches, polyacrylamide, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide, polyamine resin, polyamine, polyethyleneimine, plant gum, polyvinyl alcohol, latex, polyethylene oxide, hydrophilic cross-linked polymer Particle dispersions and derivatives or modified products thereof, basic aluminum compounds such as sulfate bands, aluminum chloride, sodium aluminate, basic aluminum chloride, and basic polyaluminum hydroxide, and water-soluble such as alumina sol easily decomposable in water. Examples thereof include polyurous metal compounds such as sex aluminum compounds, ferrous sulfate and ferric sulfate, silica sol, antifoaming agents, coloring dyes, coloring pigments, pH adjusters, pitch control agents, slime control agents and the like. It can be selected and used as needed.

<Multilayer paper for food and drink>
The multi-layer paper for food and drink has the above-mentioned paper layer and a starch-based adhesive between the layers. The number of paper layers constituting the multi-layer paper for food and drink may be selected from two or more layers according to the desired thickness and the like, but for simplification of the manufacturing process, the number of paper layers may be two or more and five or less. It is preferably two or three layers, more preferably. In the multi-layer paper for food and drink of the present invention, the raw materials, basis weight, density, and the like of the paper layers may be the same or different.
The thickness of the multilayer paper for food and drink is not particularly limited, but is preferably 100 μm or more, more preferably 120 μm or more, still more preferably 140 μm or more. The upper limit of the thickness of the multilayer paper for food and drink is not particularly limited, but is preferably 600 μm or less, more preferably 550 μm or less, and further preferably 500 μm or less.

<Adhesive>
The present invention has a starch-based adhesive between the layers of the paper layer. The starch-based adhesive used preferably has a small number of mixed microorganisms, particularly spore-forming bacteria. As such a starch-based adhesive, a starch or modified starch known in the papermaking field that has been sterilized by gas sterilization, gamma ray sterilization, high-pressure steam sterilization, intermittent sterilization, or the like can be used. Modified starch used in the papermaking field is roughly classified into those processed by a wet method in which the starch is reacted in a starch slurry and those processed by a dry method in which the starch is heated and reacted in a solid state. Since the modified starch processed in (1) is exposed to a high temperature in the process and therefore has a small number of bacteria without a special sterilization process, it can be preferably used. Examples of the dry processed starch include urea phosphorylated ester starch, phosphate esterified starch, dry low molecular weight hydroxyethylated starch, roasted dextrin and the like. In the starch-based adhesive used in the present invention, the number of bacteria contained per 1 g measured by the same method as in the number of bacteria in the paper is preferably 90 cells / g or less, preferably 60 cells / g or less. More preferably, 30 pieces / g or less is further preferable, and 15 pieces / g or less is most preferable.

-Manufacturing method For multi-layer paper for food and drink, a paper material containing pulp, filler, auxiliary agent, etc. is made into paper to form a first wet paper layer. Step A, starch-based adhesion is performed on the first wet paper layer. Step B of applying or spraying the aqueous dispersion containing the agent, step C of forming a second wet paper layer on the surface on which the aqueous dispersion is applied or sprayed, and if necessary, step B, step. It can be manufactured by repeating C.

・ Process A
The first wet paper layer is produced by a known papermaking method.
Paper making may be performed by means such as hand-making or machine-making, and as machine-making, long-net paper machine, twin-wire paper machine, Yankee paper machine, circular net paper machine, circular net short-net combination paper making A known paper machine such as a machine can be appropriately selected and used. In the present invention, it is preferable to use a multi-layer paper machine from the viewpoint of work efficiency and the like. In particular, a papermaking net, an upstream headbox provided upstream of the papermaking net, one or more downstream headboxes provided downstream of the upstream headbox, and between the upstream headbox and the downstream headbox. Further, it is preferable to form a wet paper layer by supplying the paper material from the upstream head box to the papermaking net by using a paper machine provided with a supply device for supplying the aqueous dispersion containing the starch-based adhesive.

・ Process B
In step B, an aqueous dispersion containing a starch-based adhesive is applied or sprayed onto the first wet paper layer. The solid content concentration of the starch-based adhesive in the aqueous dispersion is not particularly limited as long as it has a viscosity that can be applied or sprayed and has an adhesive effect, and is preferably 0.5 to 10% by weight. It is more preferably 0.0 to 7.0% by weight, and even more preferably 2.0 to 5.0% by weight.

A known device such as a dispenser can be used for coating. Further, a known device such as a spray nozzle can be used for spraying. From the viewpoint of increasing the interlayer adhesion strength, the amount (solid content) of the starch-based adhesive to be applied or sprayed is 0.001% by weight or more and 30% by weight or less with respect to the solid content of the wet paper layer formed in step A. , 0.01% by weight or more and 30% by weight or less is preferable, 0.05% by weight or more and 10% by weight or less is more preferable, and 0.1% by weight or more and 5% by weight or less is further preferable. The solid content of the wet paper layer is a solid content obtained by drying the wet paper layer.

As described in step A, it is preferable to use the above-mentioned paper machine in the present invention. In this case, the aqueous dispersion containing the starch-based adhesive is applied or sprayed onto the first wet paper layer obtained in step A via a feeder. The feeder is specifically a dispenser or a spray nozzle, and it is preferable that the spray nozzle is used for spraying. Further, the application or spraying of the aqueous dispersion containing the starch-based adhesive is performed over the entire width of the wet paper layer in the paper machine width direction. When an aqueous dispersion containing a starch-based adhesive is applied or sprayed over the entire width of the paper machine, the starch-based adhesive is present in a very thin layer on the entire surface of the paper layers, resulting in higher interlayer adhesion strength. ..

・ Process C
In step C, a second wet paper layer is formed on the surface on which the aqueous dispersion obtained in step B is applied or sprayed.
The method for forming the second wet paper layer is not limited, and for example, a wet paper layer is prepared in the same manner as in step A, and the wet paper layer is opposed to the surface on which the aqueous dispersion obtained in step B is applied or sprayed. A second wet paper layer can be formed by laminating in such a manner. Alternatively, a second wet paper layer may be formed by supplying a paper material on the surface on which the aqueous dispersion obtained in step B is applied or sprayed. The paper charge used in step C may be the same as or different from the paper charge used in step A.
As described above, since it is preferable to use the paper machine in the present invention, the paper material is supplied from the downstream head box onto the surface on which the aqueous dispersion obtained in step B is applied or sprayed. It is preferable to form a wet paper layer of.

By repeating step B and step C as necessary after this step C, a multilayer paper for food and drink having a desired number of layers can be produced. At this time, the paper material of the wet paper layers to be laminated may be the same as or different from the paper material forming the first and second wet paper layers.

-Other Steps The multilayer body containing at least the layers obtained in steps A to C obtains known steps such as a pressing step, a drying step, and a calendar step to become a multilayer paper for food and drink. The pressing step can be performed by a known method such as a plain press, a suction press, and a shoe press. The drying step can be performed by a known method such as a steam heater, a gas heater, an infrared heater, an electric heater, a hot air heater, a microwave, and a cylinder dryer. The calendar process can be performed by a known method such as a super calendar, a gloss calendar, a soft nip calendar, a thermal calendar, and a shoe calendar.

Further, the multi-layer paper for food and drink of the present invention may be provided with a thermoplastic resin layer, a water-resistant varnish, a water-repellent agent, or the like to enable heat-sealing processing, if necessary.
As the thermoplastic resin, polyethylene, polypropylene, polyvinyl acetate polymer and the like can be used, and polyethylene and polypropylene are preferably used from the viewpoint of productivity at the time of heat sealing and barrier property. The method for laminating the thermoplastic resin layer is not particularly limited, but a known method such as a conventional melt-extruded laminating method, a dry laminating method using a film, or a direct melt coating method can be used.
As the water resistant varnish and water repellent, it is preferable to use those that are approved as food additives as raw materials or that have obtained FDA certification and that are compatible with food safety. For example, petroleum-based resins (styrene). -Butadiene-based, acrylic-based, etc.), petroleum-based wax, etc. can be used. The coating method is not particularly limited, and known methods such as air knife coating, bar coating, blade coating, and curtain coating can be used.

In the multi-layer paper for food and drink of the present invention, the basis weight of the paper layer ^{is preferably 20 g / m 2} or more, and more preferably 30 g / m ² or more. Further, it is preferably 300 g / m ² or less, and ^{more preferably 270 g / m 2} or less.
The basis weight of the multi-layer paper for food and drink of the present invention ^{is preferably 100 g / m 2} or more, and more preferably 150 g / m ² or more. Further, it is preferably 500 g / m ² or less, and ^{more preferably 450 g / m 2} or less.

The multi-layer paper for food and drink of the present invention has a small number of bacteria in the paper and can be used for various purposes for food and drink. For example, it can be suitably used for food containers, beverage containers, yogurt containers, paper plates, paper cups, paper sheets and the like.

"Example 1"
Urea phosphorylated ester starch produced by the dry method (number of bacteria per 1 g of starch: less than 10) was dispersed in water at 100 ° C. so as to have a solid content of 3% to produce an interlayer starch.
Using 100% coniferous kraft pulp raw material, in the wire part of a multi-layer paper machine, ^{a back layer with a basis weight of 50 g / m 2} and a 2 g / m ^2- layer starch, a middle layer of 156 g / m ² , 2 g / m, respectively. Wet paper was obtained by laminating and spraying in order to form a ^two- layer starch and a surface layer of 50 g / m ^2.
Then, the obtained wet paper was squeezed and dried so that the water content in the paper was 8% to obtain a multi-layer paper for food and drink ^{having a basis weight of 260.2 g / m 2.}

The obtained multi-layer paper for food and drink was evaluated as follows. The results are shown in Table 1.
Basis weight: Measured according to JIS P 8124.
-Paper thickness: Measured according to JIS P 8118.
-Number of bacteria in paper: The number of bacteria in paper was measured by the above method.

"Comparative Example 1"
A multilayer paper for food and drink was produced and evaluated in the same manner as in Example 1 except that the interlayer starch used was acetylated starch produced by a wet method (number of bacteria per 1 g of starch: 160).

The multi-layer paper for food and drink of the present invention had a small number of bacteria in the paper and was hygienic.

Claims (3)

It has a plurality of paper layers and a starch-based adhesive between the layers.
A multi-layer paper for food and drink, characterized in that the number of bacteria in the paper is 250 cells / g or less. The multilayer paper for food and drink according to claim 1, wherein the starch-based adhesive contains modified starch processed by a dry method. The invention according to claim 1 or 2, wherein the starch-based adhesive contains one or more of urea phosphorylated ester starch, phosphate esterified starch, dry low molecular weight hydroxyethylated starch, and roasted dextrin. Multi-layer paper for food and drink.