JP3067328B2 - Food packaging sheet or film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a food packaging sheet or film having both antibacterial, antifogging and antistatic properties. More specifically, the present invention relates to a sheet or film having high safety and long-term antibacterial properties, antifogging properties, and antistatic properties even when touching food.

[0002]

2. Description of the Related Art Conventionally, food packaging is packaged with haptron paper or synthetic resin film in order to prevent contamination by dust and bacteria and to keep it clean, but in order to further enhance the effect, this packaging material is treated with an antibacterial agent. It has been proposed to be. For example, paper impregnated with a phenolic or benzoic acid-based disinfectant, or a film in which an organic halogen-based or benzimidazole-based disinfectant is kneaded, are manufactured, but have drawbacks in terms of safety and efficacy. was there.

Focusing on the fact that metal ions such as silver, copper, and zinc have antibacterial properties, a method of bonding or adding a fine metal powder to a polymer compound or a method of including a metal compound in a polymer compound has been proposed. Are known. As one of the methods, there is a method in which a polymer has a functional group having an ion exchange ability or a complex forming ability, and a metal ion is retained in the functional group. However, in this method, the interaction between the functional group and the polymer is performed. Accordingly, the polymer is liable to undergo remarkable change in physical properties, and the type of the polymer and the type and the amount of the functional group that can be used must be extremely limited.

On the other hand, metal ions having an antibacterial action are held by inorganic solid particles having an ion exchange ability,
There is a method of imparting this to a polymer (Japanese Unexamined Patent Publication No.
186804), the antibacterial activity may vary due to aggregation or uneven distribution of solid particles, and the physical properties of the polymer such as flexibility and transparency may be impaired. Usually, a large amount (2 to 3% or more) of kneading is required for embedding or the like. In addition, especially for food packaging film, it has good antibacterial properties, good appearance, high commercial value, anti-fogging properties to prevent water droplets that easily become a culture medium for bacteria, and antistatic to prevent dust from adhering. Therefore, there has been a long-awaited demand for the appearance of a food packaging sheet or film having antibacterial properties as well as antifogging properties and antistatic properties.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the deficiencies of the prior art, has a safe and effective antibacterial effect for a long period of time, and at the same time has both antifogging and antistatic properties. It is an object of the present invention to provide a food packaging article such as a film / sheet and a container processed from the sheet while maintaining suitable physical properties.

[0006]

The present invention SUMMARY OF] is allowed to carry monoglyceride octanoate, a mixture of decanoic acid monoglyceride and lauric acid monoglyceride (hereinafter respectively referred to as C _8, C ₁₀ and C _12.) In the porous silica, this Contains antibacterial properties over the long term,
The inventors have found that they have both antifogging property and antistatic property, and have reached the present invention.

[0007] Fatty acid monoglycerides produced from edible oils and fats are safe compounds as food additives so that no restrictions are imposed on the food used and the amount used. It is known that some of them have antibacterial activity, but no antibacterial properties when melted and mixed with thermoplastic resin were known. Fatty acid monoglycerides used in the present invention is a mixture of either or both the C ₁₂ to C ₈ and C _10.

[0008] Fatty acid monoglycerides C ₈ , C ₁₀ and C
The weight ratio of but the mixing ratio is not particularly limited weight and C ₁₂ to C ₈ or C _10, or C ₈ + C ₁₀ of ₁₂ C _8, C ₁₀ or _{C 8 + C 10: C 12} = 3.3~0.2: 1 exhibits excellent antibacterial properties and is preferred. For the anti-fogging property, the optimum mixing ratio differs between an environment near room temperature and a low-temperature environment such as in a refrigerator. Because of the high C ₈ and C ₁₀ are hydrophilic at 10 ° C. or more environment, easily eluted, to lose antifogging in a relatively short time, C _8, C
₁₀ or C ₈ + C ₁₀ : C ₁₂ = 5 to 0.3: 1 is preferable. At a low temperature of less than 10 ° C, hydrophobicity is emphasized and C ₈
Elution of C ₈ , C ₁₀ or C ₈ +
It is preferable to mix at a mixing ratio of C ₁₀ : C ₁₂ = _{10 to} 0.3: 1. In particular, C ₈ , C ₁₀ or C ₈ + C ₁₀ : C ₁₂ =
At a mixing ratio of 5 to 0.3: 1, relatively long-term anti-fog properties are exhibited over a wide temperature range usually used.

The porous silica used in the present invention is an ultrafine silica obtained by a wet method and has an oil absorption of 120 to 280 ml / 100.
g, an average particle diameter of 6 μm or less is desirable. Oil absorption is 1
If it is less than 20 ml / 100 g, a long-term antibacterial antifogging property cannot be sufficiently exhibited, and if it exceeds 280 ml / 100 g, a large amount of fatty acid monoglyceride is included, and the efficiency of the effective fatty acid monoglyceride is small, resulting in poor efficiency. If the average particle size is larger than the upper limit, the haze of the film increases,
It is not good because the contents of the package are difficult to see. The mixing ratio of the porous silica and the fatty acid monoglyceride was 0.1% by weight.
~ 1.0: 1 is desirable. More preferably, 0.2 to
0.4: 1. If it is below the lower limit, the fatty acid monoglyceride not supported on the porous silica is too large and there is no long-term release effect, and if it is above the upper limit, the fatty acid monoglyceride is almost completely supported on the porous silica and released to the film surface. Monoglycerides are too low, and antibacterial and antifogging properties are lost.

As a method for supporting the fatty acid monoglyceride on the porous silica, a method in which the fatty acid monoglyceride is heated to a molten state, mixed with the dried porous silica, and then oil-absorbed is preferred. The amount of the silica supporting the glyceride is 0.01 to 5% by weight, preferably 0.1% by weight in terms of the total weight of the glyceride with respect to the thermoplastic resin.
To 3% by weight, particularly preferably 0.3 to 2% by weight.
Below the lower limit, both the antibacterial and antifogging effects are insufficient.
It is not preferable to add more than the upper limit, for example, the stickiness which is unnecessary as a practical antibacterial effect is increased, and the physical properties of the sheet and the film are greatly changed.

The thermoplastic resin applied to the present invention is a polyolefin resin composed of any one of polyethylene, polypropylene, ethylene-vinyl acetate copolymer and ethylene-α-olefin copolymer, or a mixture thereof. (Here, the α-olefin of the ethylene-α-olefin copolymer
The olefin has 4 to 10 carbon atoms, 1-butene,
1-pentene, isobutene, 3-methyl-1-butene,
1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, etc.), polyamide resins such as nylon 6, nylon 12, polystyrene resins such as polystyrene and ABS resin, and polychlorinated resins. Vinyl resins such as vinyl, polyvinyl acetate, and polymethyl methacrylate; polyether resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyacetal, and polyphenylene oxide; and polyurethane resins. Among them, polyolefin resins, polyvinyl chloride, and polyamide resins are preferred.

A known method can be used as a method of forming a sheet or film. The thermoplastic resin is uniformly kneaded in advance with a Banbury-type mixer, a single-shaft or multi-shaft kneader, and processed by a usual forming method such as an inflation method, a T-die method, and a calender method to provide other functions. For this purpose, multi-layering by coextrusion or lamination with other sheets and films is also possible. It is also preferable to perform tubular biaxial stretching and tenter biaxial stretching. A commonly used thickness is 0.01 to 2 mm, preferably 0.03 to 1.5 mm.

Incidentally, plasticizers, heat stabilizers, antioxidants, fillers, lubricants, antiblocking agents, ultraviolet absorbers, coloring agents, modifiers and the like which are usually added to the resin should be used as required. I can't wait.

[0014]

[Function] C₈, C_TenAnd C₁₂Each single antibacterial activity is a species of bacteria
Type, but generally C₈≧ C_Ten> C₁₂In order
Become small. However, when each is kneaded with resin, approximately C
₈≤C_Ten<C₁₂It becomes in order. The reason is C₈And C_Ten
Is a substance with a relatively high boiling point, but still kneads with the resin
Due to considerable heat loss due to heat treatment during heating
Conceivable.

[0015] Therefore C _8, C ₁₀ mixtures hold back losses volatilization of C ₈ or C ₁₀ by adding the C ₁₂ to each alone, or C _8, C ₁₀ can be significantly reduced, further C _8, antimicrobial efficacy each antimicrobial spectrum acts Retained to phase to C ₁₀ and C ₁₂ but also is enhanced. The easy C ₈ and C ₁₀ is C _8, C ₁₀ on the surface portion of the resin due to the relatively high hydrophilicity is eluted by a sessile drop of water, therefore it antifogging effect is lowered, less hydrophilic C ₁₂ By mixing with, the dissolution can be suppressed, the anti-fogging effect can be enhanced, and the effective period can be extended.

The antistatic effect is due to a moderate surface active effect of the fatty acid monoglyceride. The long-term antibacterial, antifogging, and antistatic effects are due to the release of fatty acid monoglycerides carried on the porous silica by supplementing the fatty acid monoglycerides eluted from the surface.

[0017]

Next, the present invention will be described with reference to examples.
The invention is not limited to these examples. Example C₈And C₁₂Are 1: 2, 1: 3, 3: 1 by weight, respectively.
A composition mixed with C _TenAnd C₁₂To 1: 3, 3:
A composition mixed in a weight ratio of 1 and C₈And C _TenEqual weight
A mixture of C and C₁₂Were mixed in a 3: 1 weight ratio
Each of the compositions was made of porous silica (E silica manufactured by
200A, oil absorption 250ml / 100g, average particle size 2.5
μm) 13% by weight and 87% by weight of the composition.
This is a low-density polyethylene (Mitsubishi Kasei Co., Ltd.
F131 MFR = 1.3 ρ = 0.924)
Mixes evenly into the ground pulverized product, and twin-screw type kneading
5% by weight master batch
did. This masterbatch is mixed with low-density polyethylene (F1
31) Pellets containing 0.1%, 0.3% and 0.5%
And inflation of a 50 μm thick film
Obtained by the 法 method. Film properties were tested as described below.

Comparative Example 1 A film having a thickness of 50 μm was obtained in exactly the same manner as the sample of the present invention except that the resin was kneaded directly without using porous silica.

Comparative Example 2 A thickness of 50 was obtained in exactly the same manner as in Comparative Example 1 except that C ₈ , C ₁₀ or C ₁₂ was used alone as a monoglyceride.
A μm film was obtained. Further, a film having a thickness of 50 μm was obtained in the same manner as described above except that silver zeolite (abbreviated as X) and butyl paraoxybenzoate (abbreviated as Y) were used instead of monoglyceride.

(Sample without Addition) A film having a thickness of 50 μm was obtained by an inflation method using F131 pellets.

Test-1 An antibacterial efficacy test was carried out using the above-mentioned film sample by the following method. Antibacterial efficacy test method Staphylococcus aureus FD
A "209P (Staphylococcus aureus) Bacillus cereus (Bacillus cereus) Bacillucs Subtilis ATCC 6
633 (Bacillus subtilis) Escherichia coli IFO 3301
(Escherichia coli) was tested, and an antibacterial test was carried out according to AATCC-90. That is, each bacterium was adjusted so that the number of bacteria was about 2 to 5 × 10 ^{6 in a} plastic petri dish having a diameter of 85 mm, and was uniformly dispersed and solidified in 5 ml of an ordinary agar medium.

Each film sample 25 × was placed on the surface of the agar medium.
After attaching a 25 mm piece and culturing at 37 ° C. for 24 hours, the presence or absence of an inhibition circle was examined. The above test was performed one day after molding and one year after molding and compared. The results are shown in Tables 1-1 and 1-1.
It is shown in FIG. The examples show that they are much more effective than the comparative examples. Further, it can be seen that the result is effective not only in the film contact surface but also in the non-contact range.

[0023]

[Table 1]

[0024]

[Table 2]

Test-2 The above-mentioned film samples and strains were tested and tested according to the method of measuring the number of bacteria of the Japan Textile Hygiene Council. Table 2-1 and Table 2-2 show the results of two methods of film sterilization and non-sterilization and autoclave sterilization at 121 ° C for 20 minutes.
Shown in The film samples were obtained one day after molding and one year after molding.

As compared with the comparative examples, each of the examples of the present invention is superior, and it can be seen that they are not bacteriostatic but bactericidal.

[0027]

[Table 3]

[0028]

[Table 4]

Test-3 An antifogging test was performed on the film sample prepared above. The test was performed one day after molding and one year after molding. For high temperature test, put water in cup and 50 ± 1 ℃
Adjust to When the film of Example 1 was covered and sealed and left in an environment of 23 ° C. and 50% RH, the area of the film free from fogging at each elapsed time is shown in percentage.

In the low temperature test, place water in a cup and place at 18 ° C. ± 1 ° C.
And the film of Example 1 was covered and sealed.
The area without cloudiness for each elapsed time when left in a refrigerator at ° C. is shown in percentage. Table 3-1 shows the results.
It is shown in Table-3-2. C _8, C ₁₀ by mixing the _{C 12 C 8, C 10,} C 12 it can be seen that each anti-fogging than alone improved.

[0031]

[Table 5]

[0032]

[Table 6]

Test-4 Antistatic Effect Test Using the above-mentioned film sample, the surface resistivity was measured at 23 ° C. and 50% RH. The measurement was performed one day after molding and one year after molding. Table 4-1 and Table 4-2
Shown in All exhibited good antistatic properties.

[0034]

[Table 7]

[0035]

[Table 8]

[0036]

According to the present invention, an antibacterial property, an antifogging property, which is extremely safe and has a long-lasting effect even when in contact with the human body or food,
A food packaging sheet or film having both antistatic properties can be provided.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08K 13/02 C08K 13/02 C08L 23/00 C08L 23/00 27/06 27/06 77/00 77/00 // (C08K 13/02 3:36 5: 103) C08L 23:00 27:06 77:00 (72) Inventor Miho Hanafusa 1000 Kamoshita-cho, Midori-ku, Yokohama-shi, Kanagawa Prefecture, Mitsubishi Chemical Corporation Research Institute (56) References JP JP-A-60-49047 (JP, A) JP-A-3-9940 (JP, A) JP-A-2-58549 (JP, A) JP-A-61-120840 (JP, A) JP-A-54-36359 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08K 5/18 C08L 1/00-101/16 C08K 3 / 36,5 / 103 B65D 65/38 A23B 7/14

Claims (4)

(57) [Claims] 1. A thermoplastic resin containing 0.01 to 5% by weight of a porous silica carrying octanoic acid monoglyceride and / or decanoic acid monoglyceride and lauric acid monoglyceride based on the resin based on the content of the glyceride. A sheet or film for food packaging, comprising: 2. The thermoplastic resin is a polyolefin resin,
The food packaging sheet or film according to claim 1, which is either a polyvinyl chloride resin or a polyamide resin. 3. The food packaging sheet or film according to claim 1, wherein the weight ratio of octanoic acid monoglyceride and / or decanoic acid monoglyceride to lauric acid monoglyceride is (10 to 0.3): 1. 4. The food packaging according to claim 1, wherein the weight ratio of the porous silica to octanoic acid monoglyceride and / or decanoic acid monoglyceride to lauric acid monoglyceride is (0.1 to 1): 1. Sheet or film