JPH0453893B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is directed to cellulose coatings (films) used as coating agents and packaging materials for foods and pharmaceuticals.
Regarding the composition. [Prior art and its problems] Sodium carboxymethyl cellulose (hereinafter referred to as
CMC) Films, either alone or containing polyhydric alcohols such as glycerin or propylene glycol, are not known to be used as packaging or coating materials for food or medicine due to their lack of bending strength and high hygroscopicity. . It is known that the flexibility of methylcellulose (hereinafter referred to as MC) can be improved by adding polyhydric alcohols such as glycerin or propylene glycol to form a film, but it is highly hygroscopic and cannot be exposed to hot water. It has the disadvantage that it does not disperse at all. This drawback of not being completely dispersed in hot water is fatal for applications in which cellulose film is used as a packaging material for processed foods, for example, and the packaging material is used for cooking. [Object of the invention] The present invention relates to the modification of a film composition obtained from a mixture of CMC and MC, specifically
The purpose is to improve the flexibility (bending resistance) and hot water dispersibility of CMC and MC films. [Problems to be Solved by the Invention] As a result of intensive studies aimed at solving the drawbacks of CMC and MC films, the present inventors have found that they use CMC and MC in combination, and also use glycerin, diglycerin and A film ( The inventors discovered that such drawbacks could be solved by converting the material into a film, and completed the present invention. The CMC referred to in the present invention is one in which an average of 0.6 to 1.0 of the three hydroxyl groups per unit of anhydroglucose is substituted with a carboxymethyl group, and is commercially available from Daiichi Kogyo Seiyaku Co., Ltd., Daicel Co., Ltd., etc. You can use what is listed. The MC referred to in the present invention has an average of 1.5 to 2.0 of the 3 hydroxyl groups per unit of anhydroglucose substituted with methoxy groups, and is commercially available from Shin-Etsu Chemical Co., Ltd., Matsumoto Yushi Co., Ltd., etc. You can use what you have. CMC/MC mixing ratio (weight ratio) is 95/5~
It's 10/90. When the CMC ratio is high, the film tends to become brittle, but on the other hand, there is a tendency for it to improve hot water dispersibility, and when the MC ratio is high, the opposite is true. That is, 5% by weight or more of MC is required to improve the brittleness of CMC, and conversely, 10% by weight or more of CMC is required to improve the hot water dispersibility of MC. Therefore, the mixing ratio should be selected depending on the purpose of use. The CMC/MC mixing ratio (weight ratio) is preferably in the range of 90/10 to 60/40. The mixture of CMC and MC is used as an aqueous solution.
The content of CMC and MC in the aqueous solution should be adjusted according to the properties (especially viscosity) caused by the different grades of CMC and MC, but generally 2 to 10% by weight is preferred. If the content is too high, it becomes viscous, making it difficult to remove air bubbles generated during the subsequent mixing or emulsifying process, which is not preferable. Also, if the content is too low, it will take a long time to dry, which is undesirable. The polyhydric alcohol used in the present invention is represented by the following formula. In the common name, n=0 is glycerin, n=1
Those with n = 2 or more are usually called diglycerin, and those with n = 2 or more are called polyglycerin, manufactured by Sakamoto Pharmaceutical Co., Ltd.
Commercially available products can be used. One or two selected from these polyhydric alcohols
The use of more than one species also meets the purpose of the present invention. The amount of polyhydric alcohol used has to be balanced with the amount of acetin fat used, which will be explained later, but usually
0 to 60 parts for a total of 100 parts by weight of CMC and MC,
Preferably it is 20 to 40 parts. When a large amount of acetin fat is used, 0 parts may be sufficient.
If more than 60 parts is used, the strength of the film will drop rapidly, making it inappropriate. As the acetin fat fatty acid used in the present invention, saturated fatty acids and unsaturated fatty acids having 8 to 22 carbon atoms can be used, and specifically, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid,
Saturated fatty acids such as behenic acid, palmitoleic acid,
unsaturated fatty acids such as linoleic acid and ricinolenic acid,
Further, coconut oil, palm oil, soybean oil, rapeseed oil, beef tallow, lard, chicken fat, fish oil, etc., or fatty acids of these hydrogenated oils can be used. As for the degree of acetylation, it is desirable that an average of 1 mol or more of acetyl groups is contained per 1 mol of glycerin fatty acid ester. If the degree of acetylation is lower than 1 mol on average, the amount of non-acetylated glycerin fatty acid ester will increase, the plasticizing ability will decrease, and bleeding will occur easily, making it unsuitable. The amount of acetin fat to be used has to be balanced with the amount of polyhydric alcohol used as mentioned above, and cannot be determined simply.
Usually 0 to 40 per 100 parts by weight of CMC and MC
This is within the scope of the department. When a large amount of polyhydric alcohol is used, 0 parts may be sufficient. If you use more than 40 copies, it will bleed and will not work well. preferably 10
~25 copies range. The total amount of polyhydric alcohol acetin fat used is also important. The total amount of these two substances used is
The amount ranges from 10 to 60 parts per 100 parts by weight of CMC and MC. If it is less than 10 parts, the plasticity will be insufficient, and if it is more than 60 parts, it will be too soft and will not have enough strength and will bleed. Preferably it is in the range of 20 to 40 parts. Examples and comparative examples of the present invention will be shown and specifically explained below. [Examples and Effects of the Invention] Next is the procedure for forming a film. First, a 2 to 10% by weight CMC/MC aqueous solution is prepared.
Next, a specified amount of polyhydric alcohol and/or acetin fat was added to the CMC/MC mixed aqueous solution, and the mixture was heated at 20 to 25°C using a homogenizer.
Stir vigorously for ~3 minutes to form a mixed (or emulsified) solution. Then, use a sprayer to spray this mixed (or emulsified) liquid along the outer periphery of the object, or immerse the object in the mixed (or emulsified) liquid for 20 to 30 seconds,
Alternatively, after defoaming the mixed liquid or emulsified liquid, spread it on a flat plate with an enclosure. Finally, the film can be adjusted by drying it in a room with dry air at 30-35°C. Next, the usefulness of the present invention will be specifically illustrated with examples. Note that parts and % in the examples mean parts by weight and % by weight unless otherwise specified. A solution having the composition shown in Table 1 is vigorously stirred with a homogenizer at a temperature of 20° C. for 3 minutes to obtain a mixture (or emulsion). After degassing the resulting mixed (or emulsified) liquid, it was cast onto a flat plate with an enclosure to give a final film of 0.1 mm and 0.02 mm, and then dried at 35°C to form a film with a thickness of 0.1 mm and 0.2 mm. mm film was obtained. Table 2 shows the physical properties of the film. The evaluation was performed using the following method. (1) Bleeding property The surface of the film prepared by the casting method is traced with a finger to determine whether there is any exudate on the film surface. The film was tested two weeks after preparation, and those with no exudation were marked with ○, and those with oozing were marked with ×. (2) Bending resistance Fold a 0.02 mm thick film prepared by the casting method and pinch it between the pads of your fingers to create a crease. Next, place the folded film on a hard glass plate, and then slide a piece of wood (the head of a red pencil) over the top while firmly pressing it down with the edge of a 100-yen hardener, and observe the degree of cracking in the film. The bending resistance is displayed in the following five stages. XX: Items that are only bent and have cracks. ×: Cracks occur when creating creases with fingers. △: Cracks appear only when pressed with a piece of wood and slid. 〇: Hardened for 100 yen and cracks only when pressed and slid. ◎: No cracks at all after the above steps. (3) Hot water dispersibility When a 0.02 mm thick film prepared by the casting method is cut into 1 cm square pieces and floated in hot water at 85 to 90 degrees Celsius, the ease of water dispersion is evaluated. Displayed in stages. XX: Small pieces that do not lose their original shape at all even when stirred vigorously with a spoon. ×: Pieces can be broken into small pieces when stirred vigorously with a spoon. △: Disperses evenly when gently stirred with a spoon. 〇: Disperses evenly by simply shaking the spoon. ◎: Disperses naturally and evenly. (4) Tensile strength Measured according to the method described in JISK-6723 using a 0.1 mm thick film prepared by the casting method.

【table】

[Table] Comparative Example 1 When the cellulose component was CMC alone, the bending resistance was completely poor. Comparative Example 2 When the cellulose component was MC alone, the dispersibility in hot water was completely poor. Comparative example 3 Mixing ratio of cellulose component is CMC/MC=
In 96/4, the improvement in bending resistance was insufficient. Comparative example 4 Mixing ratio of cellulose component is CMC/MC=
At 4/96, the improvement in hot water dispersibility was insufficient. Comparative Example 5 When glycerin is used at 70 degrees with respect to cellulose component 100, the film becomes slightly sticky and the strength becomes extremely weak. Comparative Example 6 When 50 parts of acetin fat is used per 100 parts of the cellulose component, it bleeds and the film becomes sticky. Examples 1 to 12 CMC, MC,
It can be seen that the total performance is improved compared to the comparative example in terms of the usage ratios of glycerin, polyglycerin, and acetin fat.

Claims (1)

[Claims] 1. Glycerin, a mixed aqueous solution of sodium carboxymethylcellulose and methylcellulose,
A cellulose film composition obtained by mixing one or more polyhydric alcohols selected from digcerin and polyglycerin and/or acetylated glycerin fatty acid ester, and drying this mixture into a film. 2 The mixing ratio (weight ratio) of sodium carboxymethylcellulose and methylcellulose is 95:5.
The cellulose coating composition according to claim 1, wherein the ratio is 10:90. 3 The mixing ratio of one or more polyhydric alcohols selected from glycerin, diglycerin and polyglycerin is 100% in total of sodium carboxymethylcellulose and methylcellulose.
The cellulose film composition according to claim 1 or 2, wherein the amount is 0 to 60 parts by weight. 4. The cellulose coating composition according to any one of claims 1 to 3, wherein the acetylated glycerin fatty acid ester is present in an amount of 0 to 40 parts based on 100 parts by weight of sodium carboxymethylcellulose and methylcellulose. . 5 The total usage ratio of one or more polyhydric alcohols selected from glycerin, diglycerin, and polyglycerin and acetylated glycerin fatty acid ester is 10 parts by weight per 100 parts by weight of sodium carboxymethylcellulose and methylcellulose. 60 parts of the cellulose coating composition according to any one of claims 1 to 4.