JPS59172530A - Improved method for modification of cellulose film - Google Patents

Abstract

PURPOSE:To obtain a cellulose film having moisture resistance and undergoing substantially no morphological changes when wetted and redried, by impregnating a cellulose film with a mercerizing agent. CONSTITUTION:A cellulose film (e.g., cellulose acetate film) having a moisture content >=5wt% is immersed for at least one sec in at least one mercerizing agent selected from the group consisting of an aqueous solution of a caustic alkali (e.g., NaOH) of a concentration of 1-60wt%, an aqueous solution of an organic amine (e.g., methylamine) of a concentration >=20wt%, an aqueous ammonia solution of a concentration >=40wt%, and an aqueous solution of a quaternary ammonium salt (e.g., tetramethylammonium hydroxide) of a concentration of 15-85wt%, and the mercerizing agent is then removed by neutralizing with a strong or weak acid or by washing with hot water of 80-100 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for modifying modified cellulose films. More specifically, the purpose is to improve the water vapor permeability of the cellulose film and the morphological changes after wet N4'J and drying.

Cellulose film 12 has advantages such as excellent transparency and low static electricity generation, so it is widely used in clothing packaging materials, adhesive tape materials, materials, etc. However, although cellulose film has various advantages, it has disadvantages such as poor moisture resistance, large dimensional change rate after wetting and drying, and low strength when wet.

Conventionally, there have been methods to improve these drawbacks, such as adjusting the film forming speed and stretching in the warp and weft during film forming. It is true that these methods can slightly improve water vapor permeability and morphological change after wetting and drying, but the degree of improvement is not sufficient.

The present inventors have intensively studied a method of imparting moisture resistance to a cellulose film and causing almost no change in form after wetting and drying, and as a result, they have arrived at the present invention.

That is, the present invention is a method for modifying a modified cellulose film, which is characterized by impregnating the cellulose film with a mercerizing agent.

According to the present invention, since the cellulose film has excellent moisture resistance and does not change its form after wetting and drying, it is easier to handle than conventional cellulose films, and at the same time, it is possible to obtain a high-quality film. .

The present invention will be explained in detail below.

Examples of the cellulose film used in the present invention include a viscose method rayon film, a cupcyammonium method rayon film, and a cellulose acetate film.

-f, /H may be substituted with various reactive groups as long as they do not substantially impair the properties of the cellulose film.

The method for producing cellulose film includes conventional film forming methods such as solvent evaporation method and solvent substitution method. The mercerizing agent is then removed from the film.

The mercerization agents used in the present invention include caustic alkali,
One or a mixture of two or more selected from among amines, ammonia, and quaternary ammonium salts may be used. The mercerizing agent may be diluted with other substances as long as it does not interfere with the processing of the mercerizing agent. The usage properties of these mercerizing agents are 1 to 6% by weight for caustic alkali, 3 to 40% by weight for organic amines, and 20 to 40% by weight for organic amines.
An aqueous solution or 100% organic amine with a weight% or more, preferably 4oM or more, and an aqueous solution of ammonia with a content of 40ii or more, preferably 60 or more by weight, or 100% organic amine.
Ammonia, quaternary ammonium salts: 15 to 85
In terms of weight, preferably 20 to 60 M aqueous solution. When using 100% mercerizing agent, it can be used in either gas or liquid form, but it is easier to process if it is used in liquid form.

Examples of caustic alkalis include sodium hydroxide, potassium hydroxide, lithium hydroxide, and cesium hydroxide.

Yes (Aramines include methylamine, ethylamine,
Propylamine, butylamine, amylamine, heptylamine, ethylenediamine, monoethanolamine,
Examples include hydrazine hydrazide.

Examples of quaternary ammonium salts include dimethylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, and dimethylammonium hydroxide.

Methods for impregnating the material with the mercerizing agent include commonly used methods such as spraying, coating, and dipping, but any method may be used. Two u4 impregnated with mercerizing agent
is 10 to 150% by weight of caustic alkali, 20 to 150% by weight of nucleated amine, 40 to 150% of ammonia based on the weight of the film, and 3M'A of quaternary ammonium.
It is 15-150ffii%. The time for which the mercerizing agent is impregnated varies depending on the properties of the mercerizing agent, and generally cannot be specified or may be 1 second or more, and is preferably 2 seconds or more. The temperature of the mercerizing agent to be impregnated is 10°C to 100°C for caustic alkaline water, the freezing point for organic amines to 100°C for organic amines, 7°C to 100°C for ammonia, and 7°C to 100°C for quaternary ammoniums. The temperature range is from 0°C to 100°C. To remove the impregnated mercerizing agent, neutralize the mercerizing agent's glaze with a strong acid such as hydrochloric acid or sulfuric acid (or a weak acid such as acetic acid, lactic acid, or succinic acid), or use hot water at 80 to 100°C. There are methods for removing the mercerizing agent alone, or by heating it to a temperature higher than the boiling point of the mercerizing agent, but a combination of these methods can be used as long as the method does not interfere with the effects of the present invention.

In short, the time for removing the mercerizing agent may be longer than the time required to remove the mercerizing agent from the film. However, if the heating temperature exceeds 200°C, yellowing and embrittlement will occur, so it is not desirable to exceed 200°C.

In the present invention, in order to further enhance the processing effect, it is preferable to impregnate the film with water prior to mercerization. The moisture b: to be included is adjusted to 5% or more, preferably 1z% or more based on the absolute dry weight.

If the ratio is less than 5, it will take a long time for the treatment effect of the mercerizing agent to be fully exhibited, and the quality of the resulting film may not be stable.

Methods for impregnating the film with moisture include placing it in an atmosphere that maintains a certain amount of moisture in the film, spraying it with water, coating it with water, immersing it in a bath containing water, or After the above method, there is a method of removing some of the moisture from the film to maintain a constant moisture content in the film, but it is also possible to collapse the film.

In the present invention, the mercerizing agent formulation (
In order to do this, prior to the mercerizing agent impregnation treatment, a liquid that is poorly soluble in the mercerizing agent and can be adsorbed to the film, or a liquid that is insoluble in the mercerizing agent and is adsorbed on the film surface. It is desirable to use a substance that has the ability to form a film because it prevents adhesion between films during the mercerization process.

Liquids that can be adsorbed onto the cellulose film include aliphatic/aromatic hydrocarbons, oils and fats, and surfactants, among which liquids that are liquid at room temperature are preferred. Here, "mercerizing agent KM-soluble" means that the solubility at the mercerizing temperature is 10 f for 100 f of the mercerizing agent.
Refers to substances that exhibit the following solubility. 1BC [capable of being adsorbed to a cellulose film] means that the contact angle formed between the liquid and the cellulose film is 110 degrees or less.

The amount of the above liquid attached is 5 to 15"i based on the weight of the film.
The range of the amount φ is preferable. The substance having film-forming ability preferably has a molecular weight of 10,000 or more, and the adhesion amount is preferably in the range of 0.5 to 10% by weight based on the weight of the film. Polymers capable of forming a film include water-soluble polymers and water-dispersible polymers.

Further, in the present invention, the film may be shrunk by 0 to 20 inches in the warp and weft relative to the dimensions before impregnation (hereinafter referred to as original size) while impregnated with the mercer agent, or by 0.
It may be elongated by 1 to 20%. In the case of zero elongation, it is preferable to elongate the material while impregnated with a mercerizing agent, and remove the mercerizing agent in the elongated state. Although relaxation may be performed in the process of removing the mercerizing agent, new stretching increases the internal structural distortion of the film, which is not preferred.

As a stretching method, a so-called roll stretching method that utilizes the surface speed ratio of two sets of presser rollers, a pinch/tar, a clip tenter, or the like can be used.

The absolute dry weight mentioned in the text is based on Japanese Industrial Standard J.
The method described in IS L-1015, i.e.
Dry in heated air at a temperature of 105±2℃,
Humidity control of measurement sample> At Himi JIT 4, before measuring the various physical properties of the film, it was heated in an atmosphere of 20°C and humidity of 65°C.
The sample was left for more than an hour to adjust the humidity and used as a test sample.

Morphological changes after wetting and drying〉 A sample with a length of 10t:m was placed in distilled water at a temperature of 20°C for 30 minutes.
Soak for a minute, then remove from distilled water at a temperature of 20°C.
, and dried for 24 hours in a constant temperature room with a relative humidity of 40%. In addition, drying was carried out by hanging to avoid applying external force as much as possible. The degree of morphological change after drying was visually judged in five stages.

Grade 5: There is no dimensional change in warp or weft, and it is the same as the original cloth.

Grade 4: There are slight changes in warp and weft dimensions, and small wrinkles appear here and there.

Grade 3 warp, cotton size is υ, mottled thick/J% wrinkles occur.

Grade 2: A; A1, dimensional change in cotton is kana, and kana wrinkles occur on the entire surface.

Grade 1: The warp and weft dimensions have changed significantly, and severe wrinkles have appeared on the entire surface.

Moisture-proof evaluation: The moisture-proof property was evaluated based on the amount of water vapor passing through (1/day) in an atmosphere with a flow rate of 50°C and a relative humidity of 40%. Specifically, 15F distilled water was placed in an aluminum container, and the sample was sandwiched between rubber gaskets and pressed down from above to prevent water vapor from leaking. The container was left in an atmosphere at a temperature of 50° C. and a relative humidity of 40% for 15 hours, and the weight loss (Δm) was measured.

Calculate the amount of water vapor passing (f/go・Day) from the following formula: 0 Amount of water vapor passing (?/m'・Day) = 566.
２ 30. A commercially available Shichirono \/ (manufactured by Tokyo Shichirono 17 Co., Ltd.) was left in a constant temperature and humidity chamber at a temperature of 20°C and a relative humidity of 65% for 24 hours, and 10
2%''-/I, z knee d+1--
.

Country: φ Sodium hydroxide aqueous solution, ethylenediamine, liquid ammonia, and 40-J tetramethylammonium water bath solution were immersed for 60 seconds. Squeeze the liquid so that the pickup rate is 100% and size before mercerization (hereinafter referred to as original size)
can be retained.

Furthermore, place B! The temperature is 20℃ for sodium hydroxide aqueous solution,
20℃ for ethylenediamine, 14℃ for liquid ammonia
At 0°C, the temperature was 25°C for a 40% weight tetramethylammonium aqueous solution.

Then, the mercerizing agent was removed from the film. During the removal of the mercerizing agent, no new stretching was performed and the original size was maintained. To remove sodium hydroxide, immerse in hot water at 90°C for 60 seconds, then neutralize with 3-thiacetic acid at 20°C and wash with water.
In the case of 40% by weight tetramethylammonium, the same procedure as with sodium hydroxide was carried out. The results are shown in Table 1.

According to the present invention, moisture resistance is significantly improved, and there is almost no change in shape after wetting and drying.

Table 1

Claims (1)

[Claims] A method for modifying a modified cellulose film, which comprises impregnating the cellulose film with a mercerizing agent.