JPH06246882A - White laminate - Google Patents

Abstract

PURPOSE:To provide a white laminate, which has excellent antistatic properties at low humidity and favorable water resistance and solvent resistance by a method wherein nitrogen spectra having two kinds of peaks due cationic nitrogen and to un-ionized nitrogen are detected by ESCA measurement of antistatic layer. CONSTITUTION:The base material of white laminate has a thickness of 5-500mum and a light transmission of 50% or less. The antistatic layer laminated onto the base material is made of composition, which is prepared by mixing cationic nitrogen-containing substance and un-ionized nitrogen-containing substance and had film-forming properties. Thus, in the nitrogen spectra obtained by ESCA measurement of the antistatic layer, two kinds of peaks due to the cationic nitrogen and to the un-ionized nitrogen are detected. In this case, the area ratio of the peak due to the cationic nitrogen to the peak due to the un-ionized nitrogen is preferable set to 10/90-99/1. Thus, the white laminate excellent in antistatic properties at low humidity, water resistance and solvent resistance is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a white laminate which is opaque and has excellent antistatic properties at low humidity, water resistance and solvent resistance.

[0002]

2. Description of the Related Art Conventionally, white films and sheets made of thermoplastic resins such as polyolefins and polyesters, papers made of natural pulp, and laminates made of combinations thereof have been used as packaging films and magnetic recording medium substrates. It is widely used in materials and fields where opacity is required, such as general industrial films and books. However, since these base materials are insulators, they have a drawback of being easily charged by static electricity.

Further, conventionally, various measures have been taken to impart antistatic properties to these substrates. For example, a surfactant having an antistatic property, an ionic compound, a conductive substance such as a metal powder or a metal oxide, or the like is kneaded into the composition forming the base material or blended in the coating material. Then, the method of applying to the surface of the substrate has been adopted. However, the method using a surfactant and an ionic compound as the antistatic agent has a problem that the antistatic property is lowered under low humidity. On the other hand, the method using a conductive substance does not have a problem that the antistatic property is lowered even in an environment of low humidity, but it is necessary to add a large amount of a conductive substance in order to impart the antistatic property, There was a problem that transparency was lowered. Further, there is a problem that such a conductive material is expensive. On the other hand, many of these base materials are used by further laminating different types of layers or coating them. In the case of coating, since water-based or solvent-based paint is used, water resistance and solvent resistance become problems.

Therefore, it has been desired to develop a laminate which is transparent and has excellent antistatic properties, water resistance and solvent resistance.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, and an object thereof is to have excellent antistatic property at low humidity, good water resistance and good solvent resistance. To provide a white laminate.

[0006]

The white laminate of the present invention comprises:
A white laminate in which an antistatic layer is laminated on at least one surface of a base material formed of a white film or sheet made of a thermoplastic resin such as polyolefin or polyester, a paper made of natural pulp, and a laminate made of a combination thereof. In the nitrogen spectrum obtained from the ESCA measurement of the surface of the antistatic layer, two types of peaks due to cationic nitrogen and non-ionized nitrogen are detected.

In the present invention, the base material of the white laminate has a thickness of 5 to 500 μm and a light transmittance of 50% or less. This base material is, for example, an olefin resin such as polyethylene or polypropylene, polyethylene terephthalate, polyethylene isophthalate, polyethylene 2,6.
-Polyester resin typified by naphthalate, polybutylene terephthalate and copolymers thereof, polyether resin typified by polyoxymethylene, nylon-
Polyamide resin represented by 6, Nylon-66, polymeta-xylene adipamide, etc., vinyl resin represented by polystyrene, poly (meth) acrylic ester, polyacrylonitrile, polyvinyl acetate and copolymers thereof. , Polycarbonate resins and cellulosic resins represented by cellophane and acetate, and further polyimide, polyetherimide, polyphenylene sulfide, polyether sulfone, polysulfone, polyether ketone, polyether ketone ketone, fluorine-containing polymer, etc. , A material containing inorganic and organic fine particles or air bubbles, a paper made from natural pulp, or the like, and a simple substance, a copolymer, a mixture, or a laminate of many resins and papers.

In the present invention, an antistatic layer is laminated on a substrate. The antistatic layer is a coating film containing a substance containing cationic nitrogen and a substance containing non-ionized nitrogen. It was formed using a composition having a forming ability, and thus, two kinds of peaks due to cationic nitrogen and non-ionized nitrogen were detected in the nitrogen spectrum obtained from the ESCA measurement of the antistatic layer surface as described above. To do.

Examples of the substance that produces a peak due to cationic nitrogen include organic cationic compounds. Further, a low molecular weight or high molecular weight substance having a quaternized nitrogen is mentioned, but a cationic polymer is preferable.

Examples of the cationic polymer include polyethyleneimine, polydimethyldiallylammonium chloride, polyalkylenepolyamine dicyandiamide ammonium condensate, polyvinylpyridinium halide, alkyl (meth) acrylate quaternary ammonium salt,
(Meth) acrylamidoalkyl quaternary ammonium salt,
ω-chloro-poly (oxyethylene-polymethylene-alkyl quaternary ammonium salt), polyvinylbenzyltrimethylammonium salt and the like can be mentioned.

Further, as the cationic polymer, particularly as a quaternary ammonium salt polymer, polystyrene type cationic polymer, acrylic type cationic polymer, polyvinyl pyridine type polymer, cyclic integral type polymer, linear integral type polymer, so-called pendant type polymer. Examples thereof include polymers of aromatic vinyl monomers having two or more quaternary ammonium ion groups, and further polymers having a pyrrolidinium ring in the main chain.

As the counter anion of the cation, for example, halogen ions such as F ⁻ , Cl ⁻ , Br ⁻ and I ⁻ , alkyl sulphates such as methoxysulfate, ethoxysulfate, dodecylbenzene sulfonic acid, dodecyl sulfonic acid and dioctyl. Examples thereof include phosphate esters.

These polymers may be homopolymers or copolymers. Known monomers can be used as the copolymerizable monomer.

Examples of the substance which produces a peak due to non-ionized nitrogen include those obtained by tertiaryizing the above cationic nitrogen and other compounds. As the other compound, a crosslinking agent is preferable in consideration of the water resistance and solvent resistance of the coating film. The cross-linking agent is not particularly limited as long as it has non-ionized nitrogen, and is preferably an isocyanate-based or melamine-based cross-linking agent.
Particularly preferably, considering compatibility with a cationic polymer, polyether type blocked isocyanate and the like can be mentioned.

The area ratio of the peaks of cationic nitrogen and non-ionized nitrogen determined from the ESCA spectrum of the surface of the antistatic layer in the present invention is 10/90 to 99/1.
Is preferred. More preferably, the area ratio is 1
It is 0/90 to 60/40. Area ratio of peak is 10 /
When it is less than 90, the amount of cationized nitrogen component is small and the antistatic property is insufficient. On the other hand, the peak area ratio is 9
When it exceeds 9/1, the amount of non-ionized nitrogen is small and the water solubility of the coating film becomes large, resulting in insufficient water resistance.

When a coating film is formed using the coating film forming composition of the present invention, an organic or inorganic alkaline compound such as an organic or inorganic alkaline compound, for example, is added to accelerate the crosslinking reaction of the crosslinking agent.
It is desirable to use a small amount of a cross-linking curing agent composed of amine, polyamine, amidoamine, polyamidoamine, imidazole, alkali metal carbonate, and derivatives thereof.

The coating film forming composition of the present invention is water-soluble and therefore, it is preferable to use it in an aqueous solution. However, an organic solvent such as alcohol may be used in combination for the purpose of improving wettability with a substrate. Is also good. Further, other cross-linking agents, catalysts, wetting agents and the like can be added if necessary. Further, an ultraviolet absorber, a pigment, an organic filler, an inorganic filler, a lubricant, an antiblocking agent and the like may be used in combination unless the object of the present invention is impaired. Also use other binder resin together,
You may improve characteristics, such as adhesiveness and blocking property. Means for mixing when mixing and laminating multi-components is not limited, and known methods such as a high-speed stirring method, a high-pressure dispersion method, and an ultrasonic dispersion method can be arbitrarily used. A method combining these methods is also suitable.

The method of laminating the solution of the composition thus obtained on the surface of the substrate is not particularly limited, but a coating method of coating the surface of the substrate film with the solution or dispersion is particularly preferable. That is, it is preferable to apply the composition on the surface of the base material film, followed by drying and heat treatment. As a method of applying the coating layer on the base film, a known method can be applied. For example, a spray coating method, an air knife method, a river coating method, a kiss coating method, a gravure coating method, a Meyer bar method, a roll brush method and the like can be applied. The coating may be performed on the surface of the substrate after the production is completed, and in the case of a biaxially stretched film, for example, the coating may be performed after the film production process, that is, the cast raw fabric or the uniaxial stretching, and then the stretching treatment may be performed. Particularly in the case of a film, it is preferable to perform the stretching treatment in a state where the water content of the coating film after coating is 2% or less after the raw material for casting or uniaxial stretching. Two
If the stretching treatment is performed in a state of not less than 100%, the amount of cationic nitrogen on the surface increases and water resistance becomes insufficient. The ratio of cationic nitrogen to non-ionized nitrogen determined by ESCA of the present invention is smaller in the amount of cationic nitrogen than the ratio at the time of charging in the coating liquid. This is because the difference in water solubility between the cationic nitrogen-containing compound and the non-ionized nitrogen-containing compound suggests that a large amount of non-ionized nitrogen having high water solubility is present on the surface by coating and drying.
The coating amount of the aqueous solution of the coating film forming composition applied to the substrate is 0.01 to 5 g / m ² as a solid content. If the coating amount is less than 0.01 g / m ² , sufficient antistatic properties cannot be obtained. If 5 g / m ² or more is applied, blocking becomes a problem.

The white laminate produced by the above method is used as a base material for magnetic recording media such as magnetic cards, tapes and floppy disks, and for general industrial applications.
For example, it is also useful as a membrane, a telephone card, a label, a microfilm, a diazo film, an art paper, a poster paper, an antistatic plotter paper, a thermal paper, a base material of an image receiving sheet for thermal transfer recording, and a general packaging base material.

[0020]

EXAMPLES Next, examples and comparative examples of the present invention will be shown. The following evaluation methods were used in these examples. 1) Surface resistance Takeda Riken Co., Ltd. specific resistance measuring device applied voltage 500V, 2
It was measured under the conditions of 3 ° C. and 40% RH. 2) Evaluation of water resistance and solvent resistance The film was immersed in water, MEK, ethyl acetate, and acetone, and the surface resistance was measured after standing at room temperature (26 ° C) for 16 hours. No change in surface resistance before and after immersion was evaluated as ◯, and surface resistance increased after immersion was evaluated as x. 3) ESCA measurement The ESCA spectrum of the laminated surface of the film was measured with an ESCA-850 manufactured by Shimadzu Corporation using Mg-Kα as a light source with an output of 8 kW x 30 mA and a vacuum degree of 5 x 10 ^-6 Pa. The peak of cationic nitrogen is detected near 403 eV, and the peak of non-ionized nitrogen is detected near 400 eV. The area of each peak was calculated and the area ratio was calculated.

Example 1 Copolymerization of methyl methacrylate / ethyl acrylate / 2-hydroxyethyl methacrylate / dimethylaminoethyl methacrylate quaternary compound at a weight composition ratio of 50/5/15/30 was carried out by a conventional method. An aqueous polymer solution was obtained. Elastron MF-9 (Daiichi Kogyo,
20% by weight of polyalkylene oxide type) based on the solid content of the copolymer, and C as a crosslinking curing agent.
At64 (manufactured by Dai-ichi Kogyo Co., Ltd.) was added and mixed in an amount of 5.0% by weight with respect to the blocked isocyanate to obtain an aqueous solution of a composition for forming a coating film having a solid content of 7% by weight. Intrinsic viscosity 0.62
90 parts by weight of polyethylene terephthalate resin and 10 parts by weight of titanium oxide are mixed, melt-extruded at 280 to 300 ° C., and cooled by a cooling roll at 15 ° C. to obtain an unstretched white film. 85 with different speed
After being stretched 3.5 times in the machine direction between a pair of rolls at a temperature of 10 ° C., an aqueous solution of the coating film-forming composition described above was applied to a kiss coat method to give 10
g / m ² coating and drying with hot air at 70 ° C. so that the water content of the coating film is about 1%, then stretching with a tenter at 98 ° C. in the transverse direction 3.5 times, and further 200-210 ° C. After heat-setting, a biaxially stretched coated polyester film having a thickness of 100 μm was obtained. The characteristics of the obtained film are shown in Table 1.

Examples 2 to 5 The same procedure as in Example 1 was repeated except that the composition of the coating film forming composition and the substrate were changed as shown in Table 1. The properties of the obtained laminate are shown in Table 1.

Example 6 The coating composition of acrylic polymer / MF-9 = 80/20 shown in Table 2 was adjusted to an aqueous solution having a solid content of 5% by weight and applied to a commercial art paper by a hand coating method and dried at 60 ° C. Heat treatment 20
A temperature of 0 ° C. was applied to obtain a laminate. The characteristics are shown in Table 1.

Examples 8 to 10 The same processes as in Example 1 were carried out except that the base material and the coating film forming composition of Example 1 were changed as shown in Table 1 and the stretching and heat setting conditions were appropriately changed. The properties of the obtained laminate are shown in Table 1.

Comparative Examples 1 to 6 Comparative Examples 1 to 6 were carried out in the same manner except that the composition of the coating film forming composition and the substrate were changed as shown in Table 1. The properties of the obtained laminate are shown in Table 1.

Comparative Example 7 The same procedure was carried out except that the aqueous solution of the coating film forming composition of Example 1 was not applied. The properties of the obtained laminate are shown in Table 1.

[0027]

[Table 1]

The composition of each polymer in Table 1 is shown in Table 2 below.

[0029] MMA; methyl methacrylate EA; ethyl acrylate HEMA; 2-hydroxyethyl methacrylate DM; trimethylaminoethyl methacrylate hydrochloride ST; sodium parastyrene sulfonate

As shown in Table 1, the antistatic white laminates of the examples of the present invention have small surface resistance and excellent antistatic properties.
It also has excellent water resistance and solvent resistance. On the other hand, Comparative Example 1 is poor in water resistance, and Comparative Example 2 is inferior in antistatic property. Comparative Examples 2 and 3 are inferior in antistatic property. Comparative Example 4 is excellent in antistatic property but inferior in water resistance and solvent resistance. Comparative Example 5
Has excellent water resistance but poor antistatic property. Comparative Example 6 is inferior in antistatic property at low humidity and inferior in water resistance. Comparative Example 7 has no antistatic property.

[0031]

As described above, the white laminate of the present invention is excellent in antistatic property at low humidity, and is also excellent in water resistance and solvent resistance. It can be widely and suitably used for applications and various packaging applications.

[Brief description of drawings]

FIG. 1 is an ESCA spectrum obtained in Example 1. The vertical axis in the figure represents the peak intensity, and the horizontal axis represents the binding energy. The vertical axis represents the intensity of the largest of the two peaks as 100%. The peaks in the figure are obtained by mechanically smoothing the spectrum.

[Explanation of symbols]

 1 Peak of cationic nitrogen 2 Peak of non-ionized nitrogen

Front page continuation (72) Inventor Kazuhiro Abe 2-1-1 Katata, Otsu City, Shiga Prefecture, Toyobo Co., Ltd. (72) Inventor Mutsuko Kawaguchi 2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo Ltd. Inside General Research Institute, Inc. (72) Inventor Koji Yamada, 1-1 1-1 Katata, Otsu City, Shiga Prefecture Inside Toyobo Co., Ltd.

Claims (2)

[Claims] 1. A laminate in which an antistatic layer is laminated on at least one surface of a substrate having (a) a thickness of 5 to 500 μm and (b) a light transmittance of 50% or less, and the ESCA of the antistatic layer surface. In the nitrogen spectrum obtained from the measurement, two types of peaks due to cationic nitrogen and non-ionized nitrogen are detected, and a white laminate. 2. The white laminate according to claim 1, wherein the area ratio of the peaks of the cationic nitrogen and the non-ionized nitrogen is in the range of 10/90 to 99/1.