JP2005350489A - Frosted cellophane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize the frosting of a cellophane and provide a beautiful frosted cellophane by reducing the luster of its surface. <P>SOLUTION: This frosted cellophane prepared from viscous and containing 0.8-12 pt. wt. polymethyl methacrylate powder having ≥2 μm mean particle diameter, as dispersed is provided by satisfying 30-90 % haze value in the measurement according to the JIS-K-7361-1 and showing 6-70 % gloss value at 60° in the measurement according to the JIS-Z-8741, 1.0x10<SP>9</SP>-9.9x10<SP>9</SP>Ω/sq. surface intrinsic resistivity in the measurement according to the JIS-K-6911 and ≥0.23 μm (Ra) arithmetic mean coarseness, ≥1.77 μm (Ry) maximum height, ≥1.22 μm (Rz) 10 points mean coarseness and ≥0.30 μm (Rq) square mean coarseness in the measurement according to the JIS-B-0601. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a matte cellophane.

  In general, various resin films such as polypropylene, polyester, and polyethylene often have gloss on the surface of the film or gloss. The resin film is widely used at present because it is inexpensive as a packaging material and excellent in handling. On the other hand, when packaging an article, depending on the article, the gloss specific to the resin film does not match the image of the article itself, and there is a concern about glossiness such as gloss. ) Has been requested.

  In such a case, conventionally, the resin film has been subjected to a treatment for reducing the gloss on the surface of the resin film by applying a treatment such as sand blasting and after-embossing and applying a matte ink. However, since any method and process require a separate process, the manufacturing cost is high.

  Therefore, improvement of the resin itself constituting the film has been proposed. For example, in the case of a polyester film, there is a film in which a polyamide resin is blended with a polyester resin to adjust the translucency (haze value) of the film itself (see, for example, Patent Document 1). Moreover, in the polypropylene film, there is a film prepared by blending a polyamide resin and a modified polyolefin resin in addition to the polypropylene resin (see, for example, Patent Document 2).

  By the way, cellophane is excellent in antistatic property and absorbs moisture etc. in addition to resin film. In addition, it has an appropriate stickiness, and has a good foldability and cutability, so that the folds are relatively easily maintained. Has characteristics. For this reason, cellophane is used for packaging materials different from resin films.

As described above, various methods for matting (translucent) the resin film have been reported. On the other hand, cellophane has not yet found a cellophane having a matte tone with suitable properties despite the various demands, and currently does not fully meet the demands for packaging and the like.
JP-A-7-188534 Japanese Patent Laid-Open No. 10-158445

  The present invention has been made in view of the above points, and provides a beautiful matting cellophane that realizes matting in cellophane and suppresses the gloss of the surface.

  That is, the invention of claim 1 is a cellophane prepared from viscose, comprising 0.8 to 12 parts by weight of polymethyl methacrylate powder dispersed per 100 parts by weight of cellulose in the dry weight of the cellophane. Matte cellophane characterized by the fact that

  The invention of claim 2 relates to the matte cellophane according to claim 1, wherein the haze value is 30 to 90% in the measurement according to JIS-K-7361-1.

  The invention according to claim 3 relates to the matted cellophane according to claim 1 or 2, wherein the gloss value at 60 degrees is 5 to 70% in the measurement according to JIS-Z-8741.

According to a fourth aspect of the present invention, in the measurement according to JIS-K-6911, the surface specific resistivity is 1.0 × 10 ^{9 to} 9.9 × 10 ⁹ Ω / □. Related to the matted cellophane described.

  The invention according to claim 5 relates to the matted cellophane according to any one of claims 1 to 4, wherein an average particle size of the polymethyl methacrylate powder is 2 μm or more.

  In the invention of claim 6, in the measurement according to JIS-B-0601, the arithmetic average roughness (Ra) is 0.23 μm or more, the maximum height (Ry) is 1.77 μm or more, and the 10-point average roughness (Rz) is The matte cellophane according to any one of claims 1 to 5, which has a mean square roughness (Rq) of not less than 1.22 µm and a root mean square roughness (Rq) of not less than 0.30 µm.

  According to the matted cellophane according to the invention of claim 1, since 0.8 to 12 parts by weight of polymethyl methacrylate powder is dispersed and contained per 100 parts by weight of cellulose in the dry weight of cellophane, matting in cellophane is achieved. Can be realized.

  According to the matte cellophane according to the invention of claim 2, in the invention of claim 1, since the haze value is 30 to 90% in the measurement in JIS-K-7361-1, a suitable matte cellophane is obtained. Can do.

  According to the matte cellophane according to the invention of claim 3, in the invention of claim 1 or 2, since the gross value is 5 to 70% in the measurement in JIS-Z-8741, the cellophane itself is prevented from being shone. It can be matte.

According to the matte cellophane according to the invention of claim 4, in the invention of any one of claims 1 to 3, the surface resistivity is 1.0 × 10 ^{9 to} 9 in the measurement according to JIS-K-6911. Since it is 9 × 10 ⁹ Ω / □, it has an antistatic performance superior to that of a conventional polyolefin film.

  According to the matting cellophane according to the invention of claim 5, in the invention according to any one of claims 1 to 4, the average particle size of the polymethyl methacrylate powder is 2 μm or more. And the feel (texture) of cellophane itself.

  According to the matting cellophane according to the invention of claim 6, in the invention of any one of claims 1 to 5, in order to satisfy each index of surface roughness specified in JIS-B-0601, a matte tone The feel (texture) corresponding to can be maintained.

  The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view of the matted cellophane of the present invention, FIG. 2 is a schematic process diagram of the matted cellophane of the present invention, and FIG. 3 is a surface schematic diagram of the matted cellophane of the present invention.

  As shown in FIG. 1, in the matted cellophane 10 of the present invention, polymethyl methacrylate powder 12 is uniformly dispersed in a base layer portion 11 made of cellulose obtained by coagulation and conversion of viscose. The thickness tc of the cellophane base layer is appropriately selected according to various purposes of use, but is generally 20 to 50 μm, and is mainly formed into a film.

  Then, the manufacturing method of the said matting cellophane is demonstrated using the schematic process drawing shown in FIG. Usually, fiber (cellulose) obtained from cotton, pulp, waste paper and the like is prepared into viscose by reacting with carbon disulfide under alkali. Further, the polymethyl methacrylate powder (denoted as PMMA in the figure) is uniformly dispersed in a mixture of water and a dispersant (surfactant) to form a slurry.

  The slurry is mixed in the viscose so as to prevent foaming, and the polymethyl methacrylate powder is homogeneously mixed in the viscose by appropriate stirring. The viscose containing the slurry is released while being formed into a film by a hopper or the like in a coagulation bath containing sulfuric acid and sodium sulfate. In this way, viscose is converted (regenerated) to cellulose (regenerated cellulose). Thereafter, washing with water, desulfurization, bleaching and the like are performed to obtain the matted cellophane of the present invention.

  In particular, as defined in the invention of claim 1, in the matted cellophane 10, the polymethyl methacrylate powder 12 is preferably 0.8 to 12 parts by weight, preferably 100 parts by weight (dry weight) of cellulose corresponding to the base layer part 11. Is dispersed in an amount of 3 to 12 parts by weight. In addition, since polymethyl methacrylate has acid resistance and alkali resistance, it does not react even in the coagulation bath. Furthermore, since specific gravity is equal to viscose, water, etc., it is preferably used because it is well dispersed during mixing and stirring.

  Usually, when the base layer portion 11 is made of viscose-converted cellulose (99% by weight or more), the completed cellophane (film) is almost transparent. However, when the polymethyl methacrylate powder 12 is dispersed in an amount of 0.8 to 12 parts by weight, preferably 3 to 12 parts by weight, scattering of incident light may occur in the cellophane due to the polymethyl methacrylate powder. It is done. Furthermore, it is assumed that irregular reflection occurs on the surface of the cellophane as the polymethyl methacrylate powder appears on the surface. As a result, as a whole, the transparency of the cellophane film is lowered, resulting in a milky color as a whole and a matte state.

  Therefore, as specified in the invention of claim 2, the haze value is preferably 30 to 90% in the measurement according to JIS-K-7361-1 (1997). Is preferably 60 to 90%.

  Similarly, as defined in the invention of claim 3, the gross value is preferably 6 to 70% at a gloss value of 60 degrees in the measurement of the gross value in JIS-Z-8741 (1983). The gloss value is preferably 6 to 30%.

  By setting the haze value and the gloss value in the above-mentioned range in general, the cellophane film becomes opaque and the matte tone (matte tone) in the cellophane film can be visually recognized. In addition, in the cellophane film, the amount of polymethyl methacrylate powder added can be adjusted according to the demand of the customer, so the haze value and gloss value described above are free as long as the matte tone is secured. Set to

  As will be apparent from Examples described later, as the proportion of the polymethyl methacrylate powder dispersed increases, the haze value increases and the gloss value decreases. However, when the polymethyl methacrylate powder in the cellophane is dispersed in an amount exceeding 12 parts by weight, no significant change in haze value or gloss value is observed, and the matte effect reaches its peak.

  Further, in order to obtain a clearly recognized good haze value and gloss value, the dispersion amount of the polymethyl methacrylate powder is 0.8 parts by weight or more, preferably 3 parts by weight or more with respect to 100 parts by weight of cellulose. It is desirable.

As already described in the background art, the cellophane film has excellent antistatic performance as compared with a polyolefin resin film. Therefore, the surface resistivity can be used as an index for the antistatic performance. That is, as specified in the invention of claim 4, the surface resistivity of the matted cellophane of the present invention is 1.0 × 10 ^{9 to} 9.9 × 10 as measured in JIS-K-6911 (1995). ^{The range of 9} Ω / □ (or Ω / sq.) Is preferably used. In the present specification, the surface resistivity is simply expressed as “Ω / □” to distinguish it from resistance (Ω).

  As obvious from comparison with the matte-tone polyolefin resin film (polypropylene film) in the examples, the matte cellophane of the present invention has a surface resistivity that is extremely lower than that of the resin film. Therefore, the charge amount of the cellophane film is small, and it becomes difficult to draw the contents to the cellophane film surface. For example, it is also promising as a packaging material for matte granules, especially for encapsulating and packaging powdered drugs or granules by dispensing prescriptions, and for packaging powdered foods such as bonito and sprinkles. In addition, it is difficult to attract foreign substances such as dust and dust in the air, which is preferable in terms of hygiene.

  For polymethyl methacrylate, as specified in the invention of claim 5, a substantially spherical product having an average particle size of 2 μm or more is preferably used, and the average particle size is generally 2 to 12 μm. In particular, as disclosed in the examples, an average particle size of around 4.5 μm is suitable.

  According to the verification by the inventors, when the content of polymethyl methacrylate powder having different average particle diameters in the cellulose is the same (the same weight part), for example, the average particle diameter is 4.5 μm and the average particle diameter is 10 μm. It is shown that when 10 parts by weight of both are dispersed, the haze value increases (the gloss value decreases) as the cellophane is added with polymethyl methacrylate powder having a small average particle diameter. Thus, it is estimated that the smaller the average particle size, the easier it is for incident light scattering and irregular reflection to occur (see the surface schematic diagram of FIG. 3).

  In the schematic diagrams (a) and (b) of FIG. 3, reference numeral 10A denotes a matted cellophane (added polymethyl methacrylate powder having a large average particle size), and 10B denotes a matted cellophane (polymethacrylic having a small average particle size). 11a and 11b are base layer portions, 12a is a polymethyl methacrylate powder (average particle size is large), and 12b is a polymethyl methacrylate powder (small average particle size).

  When the average particle size of polymethyl methacrylate is made finer than 2 μm, it becomes extremely difficult to disperse polymethyl methacrylate powder into viscose. Moreover, since it is difficult to obtain a feel (texture) such as surface roughness, it is considered that the lower limit is approximately 2 μm.

  On the other hand, when the average particle diameter of the polymethyl methacrylate powder to be added is larger than 15 μm, depending on the thickness of the cellophane film, the cellophane film itself may feel rough due to dispersion of the polymethyl methacrylate powder. End up. Therefore, it is considered that the upper limit is generally an average particle diameter of 10 to 12 μm.

  In the matte cellophane of the present invention, in addition to the optical characteristics such as the haze value and the gloss value described so far, the feel (texture) of the cellophane surface is also an index of the surface roughness defined in the invention of claim 6 Indicated by. That is, in the measurement according to JIS-B-0601 (1994), the matted cellophane of the present invention has an arithmetic average roughness (Ra) of 0.23 μm or more, a maximum height (Ry) of 1.77 μm or more, and a 10-point average roughness. The thickness (Rz) satisfies the physical properties of 1.22 μm or more, and the root mean square roughness (Rq) satisfies the properties of 0.30 μm or more.

  Each physical property index of the surface roughness increases almost in proportion to the blending amount of the polymethyl methacrylate powder as in Examples described later. Further, it is preferable to satisfy at least the above range in order to maintain a touch (texture) corresponding to a matte tone (matte tone).

  As apparent from the above description, the matted cellophane contains polymethyl methacrylate powder, and thus has a cloudy color tone as a whole. Therefore, it is useful as a packaging material for which a calm color tone, a high-class feeling, and the like are desired. In particular, individual packaging of chocolate, strawberries, caramel, gum, etc. is also possible in consideration of the folding property and twistability peculiar to cellophane. Further, it can be substituted for glassine paper depending on the application. For example, in addition to uses such as sticking to visible portions of envelopes with windows, they are also considered as packaging materials for butter and confectionery.

  Next, examples of the present invention will be described. First, matted cellophane samples (Sample 1 to Sample 10) in which the amount of polymethyl methacrylate powder added (PMMA content) was changed were prepared. The physical properties of Sample 1 to Sample 10 and Comparative Example were measured by the following method.

[Sample preparation]
In a slurry preparation tank, polymethyl methacrylate powder (manufactured by Nippon Shokubai Co., Ltd .: Eposta MA1004 (average particle size 4-5 μm)) is uniformly stirred into a water / dispersant (surfactant) mixture to form a slurry. I made a thing. In a viscose prepared by a conventional method, the added amount of the slurry was changed for each sample and mixed. Subsequently, viscose containing polymethyl methacrylate powder was released into the coagulation bath while forming a film. The regenerated cellulose obtained by conversion in this way was washed with water, desulfurized, bleached, etc., and each matted cellophane was prepared (Sample 1 to Sample 10).

[Measurement of content of polymethyl methacrylate powder]
Samples 1 to 10 prepared according to the above production method were each cut out by a predetermined weight, and sulfuric acid solution (50%) was added to dissolve cellulose from each matted cellophane of the sample. This solution was washed with water and filtered, and the dry weight of the polymethyl methacrylate powder remaining as a residue was measured and calculated as the weight ratio (parts by weight) of the polymethyl methacrylate powder to the unit cellulose weight.

〔Measurement condition〕
The measurement and evaluation of the following items were performed under the conditions of standard temperature state class 2 (temperature 20 ± 2 ° C.) and standard humidity condition class 5 (65 ± 5%) in JIS-Z-8703 (1983).

[Measurement of surface roughness]
Arithmetic average roughness (Ra), maximum height (Ry), 10-point average roughness (Rz), and root mean square roughness (Rq) were adopted as indices of surface roughness. Measurement is performed under the conditions of the above standard temperature condition level 2 and standard humidity condition level 5 for 8 hours or more, then using Mitutoyo Corporation contact type surface roughness measuring machine Surf Test SJ-301, JIS-B- In accordance with 0601 (1994), the measurement speed was 0.5 mm / s.

[Measurement of thickness]
After conditioning for 8 hours or more under the conditions of standard temperature level 2 and standard humidity level 5 described above, Citizen Watch Co., Ltd .: MEI-10 Thickness measurement by stacking 10 samples with a JIS paper thickness measuring machine The thickness per sheet was calculated.

(Measurement of basis weight)
After conditioning for 8 hours or more under the conditions of the above standard temperature condition class 2 and standard humidity condition class 5, each sample is cut to a size of 0.1 m ² and the weight is made by Shimadzu Corporation: Electronic Analytical Balance AGE- The weight per 1 m ² was calculated as basis weight as measured by 320G.

[Measurement of tensile strength and elongation]
After conditioning for 8 hours or more under the conditions of standard temperature level 2 and standard humidity level 5 described above, Orientec Co., Ltd .: Tensilon Universal Testing Machine RTA-100 is used, based on JIS-Z-1521 (1995), The measurement was performed with a grip interval of 100 mm, a sample length of 250 mm, and a tensile speed of 300 mm / min.

[Measurement of haze value]
After conditioning for 8 hours or more under the conditions of the above-mentioned standard temperature state grade 2 and standard humidity state grade 5, using Nippon Denshoku Industries Co., Ltd .: Haze Meter NDH2000, in accordance with JIS-K-7361-1 (1997) The haze value was measured by a single sheet transmission method.

[Measurement of gross value]
After conditioning for 8 hours or more under the conditions of the above-mentioned standard temperature state class 2 and standard humidity state class 5, using Nippon Denshoku Industries Co., Ltd .: Gloss Meter VG2000, in accordance with JIS-Z-8741 (1983), 60 The degree of gloss value was measured.

[Measurement of surface resistivity]
After conditioning for 8 hours or more under the conditions of the above standard temperature state class 2 and standard humidity condition class 5, Mitsubishi Oil Chemical Co., Ltd .: JIS-K-6911 (high resistance-resistivity meter (MCP-HT260) is used. 1995), the surface resistivity (Ω / □) was measured with a measured applied voltage of 100V.

  Table 1 below shows the measurement results of the physical properties of Samples 1 to 10. In addition, as a comparative example 1, a matte (matte) polypropylene film (Nimura Chemical Co., Ltd .: FOR-M), and as a comparative example 2, a matte (matte) processed acetate film (manufactured by Clarifoil Co., Ltd.) : Measurement of M28) was also attempted. In the table, PMMA represents polymethyl methacrylate powder. In addition, “longitudinal” and “lateral” in tensile strength and elongation are vertical in the direction according to the film forming direction and horizontal in the direction perpendicular to the film forming direction.

  As understood from Table 1, as the content of polymethyl methacrylate powder increased in any sample, an increase in haze value and a decrease in gloss value were confirmed. Among the samples 1 to 10, the cellophane film having a good matte tone is the sample 3 to the sample 10, and the matte tone of the samples 5 to 10 is particularly remarkable. As apparent from the comparison with Sample 9 and Sample 10, when the content of the polymethyl methacrylate powder exceeds 12 parts by weight, the change in haze value and gloss value slows down. The part is considered the upper limit delimiter.

When the surface resistivity is compared, all samples are sufficiently lower than the polypropylene film of Comparative Example 1. That is, it can be seen that the cellophane film of each sample is less likely to be charged with static electricity and is less likely to attract dust, dust, and the like. Therefore, it was concluded that the surface resistivity was preferably in the range of 1.0 × 10 ^{9 to} 9.9 × 10 ⁹ Ω / □ while including each sample and taking into account the measurement difference. In addition, it can be said that the surface seen in Comparative Example 2 is inferior in the matte tone as compared with the acetate film in which the matte process (matte process) is performed.

[Evaluation of average particle size of polymethyl methacrylate powder]
The inventors have found that it is preferable that the content of polymethyl methacrylate powder per 100 parts by weight of cellulose is 0.8 to 12 parts by weight, more preferably 3 to 12 parts by weight. The following samples were prepared to evaluate the relationship between the particle size of the powder and the matte tone (matte tone).

  Instead of polymethyl methacrylate powder having an average particle size of 4 to 5 μm (made by Nippon Shokubai Co., Ltd .: Eposta MA1004) used for the matted cellophane of Sample 1 to Sample 10, the average particle size of the powder was 10 μm (8 to 12 μm). Sample 11 containing approximately 10 parts by weight of polymethyl methacrylate powder per 100 parts by weight of cellulose in the dry weight of cellophane in accordance with the above-mentioned production method using polymethyl methacrylate powder (manufactured by Eposta MA1010). Created.

  Here, the above-mentioned sample 8 has a haze value of 86.5% and a gloss value of 6.9% (see Table 1). On the other hand, the sample 11 has a haze value of 83.1% and a gloss value of 8.7%. As a result, when the contents are substantially the same, the degree of matte tone increases as the average particle size decreases.

  However, when the average particle size is less than 2 μm, the dispersibility of the polymethyl methacrylate powder in viscose becomes a problem. On the other hand, when polymethyl methacrylate powder (for example, average particle diameter of 15 μm) greatly exceeding the average particle diameter of 10 μm is contained, a feeling of roughness somewhat increases in the feeling (touch) of the matted cellophane itself.

  Therefore, the average particle size of the polymethyl methacrylate powder is desirably 2 μm or more in consideration of the feel of the matted cellophane itself, the ease of production, and the like. It is estimated that the average particle size is preferably about 2 to 12 μm.

It is a cross-sectional schematic diagram of the matted cellophane of the present invention. It is a schematic process drawing of the matted cellophane of the present invention. It is a surface schematic diagram of the matted cellophane of this invention.

Explanation of symbols

10, 10A, 10B Matte cellophane 11, 11a, 11b Base layer part 12, 12a, 12b Polymethyl methacrylate powder

Claims (6)

  A matte cellophane prepared from viscose, comprising 0.8 to 12 parts by weight of polymethyl methacrylate powder dispersed per 100 parts by weight of cellulose in the dry weight of the cellophane .   The matted cellophane according to claim 1, wherein the haze value is 30 to 90% in the measurement according to JIS-K-7361-1.   The matted cellophane according to claim 1 or 2, wherein the gloss value at 60 degrees is 5 to 70% in the measurement according to JIS-Z-8741. The matted cellophane according to any one of claims 1 to 3, wherein the surface resistivity is 1.0 × 10 ^{9 to} 9.9 × 10 ⁹ Ω / □ in the measurement according to JIS-K-6911.   The matted cellophane according to any one of claims 1 to 4, wherein an average particle diameter of the polymethyl methacrylate powder is 2 µm or more.   In the measurement according to JIS-B-0601, the arithmetic average roughness (Ra) is 0.23 μm or more, the maximum height (Ry) is 1.77 μm or more, the 10-point average roughness (Rz) is 1.22 μm or more, and the mean square The matte cellophane according to any one of claims 1 to 5, wherein the roughness (Rq) is 0.30 µm or more.

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