TW201532813A - Thermoplastic resin film - Google Patents

Abstract

This thermoplastic resin film has at least one film layer molded from a resin composition, and is characterized in that the resin composition for forming the film layer contains a thermoplastic resin, a photostabilizer (1) having a molecular weight of 600 or less, and a photostabilizer (2) having a molecular weight of at least 650. In the thermoplastic resin film, photodegradation due to inactivation of the photostabilizers can be suppressed. Through use of the thermoplastic resin film, it is possible to provide: a label and printing paper in which degradation or discoloration of a substrate does not readily occur even in prolonged exposure to light; a reflector whereby excellent performance can be maintained for a long time; and a liquid crystal display device, an electric signboard, and an illumination device which use the reflector.

Description

Thermoplastic resin film

The present invention relates to a thermoplastic resin film which is suitable for light resistance in various applications. The thermoplastic resin film of the present invention has a characteristic that it is not easily deteriorated even when it is exposed to light for a long period of time, and is excellent in durability.

Moreover, the present invention relates to a printing paper and a label using the above thermoplastic resin film. Further, the present invention relates to a reflector using the above thermoplastic resin film. Further, the present invention relates to a liquid crystal display device, a lighting kanban, and a lighting fixture using the above reflector.

The following methods have been increasing in recent years: a thermoplastic resin film, in particular, a composite laminated sheet-like film or a multilayer resin stretched film is used as a printing paper, and the printing paper is printed to obtain a printed matter, and the printed matter is disposed as a poster for a long time. The notice is placed at a place where the sunlight is irradiated, such as an outdoor window or a shop window, or the printed matter is incorporated into the display surface of the lighting kanban (see, for example, Patent Documents 1 and 2).

In such a case, there is a case where the printed matter is exposed to light for a long period of time and the surface of the printed matter is deteriorated or discolored. Depending on the situation, there are cases where problems such as dropping of the printed pattern occur.

Further, even when a composite laminated sheet-like film or a multilayer resin stretched film is used as the printing paper, when the printed matter is used as a label, there is a case where the label is exposed to light for a long period of time, and the printed matter is deteriorated or discolored. Happening.

In addition, a backlit liquid crystal display device or a lighting kanban having a built-in light source and illuminating light from the back surface of the display panel (the opposite side of the display surface) is easily recognized. A reflector is provided in most of the built-in light sources (backlights), and is designed to efficiently reflect light from the light source to the display surface side such as a liquid crystal screen.

Further, a reflector is also provided in the fluorescent lamp or the LED illumination device, and is designed to reflect light from the light source to the irradiation surface side.

Among such reflectors, a thermoplastic resin film has been previously used, in which a white polyester film is often used. In addition, a reflector using a white polyolefin film having a smaller change in color tone than a polyester film has been proposed (see, for example, Patent Documents 3 and 4). Most of the reflectors using the white polyolefin film achieve a high light reflection performance by making a porous or blending a filler having a relatively high refractive index and providing a large amount of light refraction interface.

On the other hand, there have been proposed a number of thermoplastic resin films in which a resin composition in which an additive is added to a thermoplastic resin is formed into a film shape to improve light resistance.

An example of the additive is a hindered amine light stabilizer (hereinafter referred to as "HALS"). Specifically, it is disclosed that the multilayer film of the thermoplastic resin contains 0.01 to 2 parts by mass of HALS (for example, refer to Patent Document 5) or HALS having a molecular weight of 500 or more (for example, refer to Patent Document 6).

Further, in the use of a thermoplastic resin film as a reflector for backlights, the reflector is also exposed to strong light from a light source for several to several decades. Therefore, in the reflector including the white polyolefin film, HALS (0.001 to 1% by mass) may be blended as needed in order to improve light resistance (see, for example, Patent Document 7).

Further, it has been revealed that HALS and an ultraviolet absorber are used in combination (for example, refer to Patent Document 8). Among them, revealing the use of three The ultraviolet absorber is used as an ultraviolet absorber (for example, refer to Patent Document 9), or a combination of a primary antioxidant and a secondary antioxidant is used as the ultraviolet absorber (for example, see Patent Document 10).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-48283

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2002-36470

[Patent Document 3] Japanese Patent Laid-Open No. Hei 8-262208

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2003-176367

[Patent Document 5] Japanese Patent Laid-Open No. Hei 10-315397

[Patent Document 6] Japanese Patent Laid-Open No. Hei 10-16169

[Patent Document 7] Japanese Patent Laid-Open Publication No. 2002-031704

[Patent Document 8] Japanese Patent Laid-Open Publication No. 2010-037442

[Patent Document 9] Japanese Patent Laid-Open Publication No. 2004-317818

[Patent Document 10] Japanese Patent Laid-Open Publication No. 2008-216598

It is considered that the photo-deterioration of the thermoplastic resin film is a process in which the thermoplastic resin is gradually oxidized and decomposed by radicals generated by light or heat. HALS has the function of capturing the free radicals and inactivating them, but if the free radicals are captured, the HALS itself is inactivated.

Therefore, if the content of the HALS in the thermoplastic resin film is too small, discoloration of the thermoplastic resin film cannot be suppressed. On the other hand, even if the content of the HALS is too large, it is not only effective in suppressing discoloration of the thermoplastic resin film, but also discoloration of the thermoplastic resin film due to the color of the HALS itself. Therefore, the amount of HALS added is naturally limited.

On the other hand, for example, printing paper or a reflector used in a lighting kanban is exposed to light for a long time, day and night. Further, as a liquid crystal display using a reflector, a high-intensity built-in light source is further required as its image quality is improved, and thus the power is higher than that of the prior light source. Along with this, the reflector is exposed to light of a greater amount of light.

Due to this situation, even in the long-term exposure to light as in years to decades In this case, it is also highly desirable to maintain the color tone if it is a printing paper, and to maintain excellent light reflection performance when it is a reflector, and to maintain excellent light reflection performance for the thermoplastic resin film used in the above, and to suppress the light stabilizer by the light stabilizer. The necessity of photodegradation caused by inactivation is increasing.

An object of the present invention is to provide a thermoplastic resin film capable of suppressing photodegradation caused by deactivation of a light stabilizer, and using the thermoplastic resin film, and deterioration of the substrate is less likely to occur even when exposed to light for a long period of time or Discolored printing papers and labels, and liquid crystal display devices, lighting panels, and lighting devices that use reflectors that maintain high light reflectance for a long period of time.

Therefore, the inventors of the present invention have conducted intensive studies to solve such problems, and as a result, have found that the intended purpose can be attained by using two or more specific light stabilizers, and the present invention has been achieved. That is, the present invention has the following constitution.

[1] A thermoplastic resin film comprising one or more layers of a resin composition formed of the resin composition, wherein the resin composition forming the film layer contains a thermoplastic resin and has a light stability of 600 or less. The agent (1) and the light stabilizer (2) having a molecular weight of 650 or more.

[2] The thermoplastic resin film according to [1], wherein the light stabilizer (1) is contained in an amount of 0.01 to 1% by mass based on the total amount of the solid content of the resin composition, and the light stabilizer (2) The content of the total solid content of the resin composition is 0.01 to 1% by mass.

[3] The thermoplastic resin film according to [1] or [2] wherein the light stabilizer (2) is a hindered amine light stabilizer.

[4] The thermoplastic resin film according to any one of the above [1], wherein the resin composition further comprises a phenolic antioxidant represented by the following formula (1) and represented by the following formula (2) At least one of the antioxidants,

(In the formula (1), any one of R ¹ and R ³ is a hydroxyl group, the other represents a hydrogen atom; R ² represents an alkyl group having a carbon number of 3 or more; and R ⁴ represents a branched alkyl group having 1 to 6 carbon atoms; n; n represents an integer from 1 to 3; when n is 1, L is a substituent; when n is 2 or 3, L is a linking group, and a plurality of R ¹ to R ⁴ are the same or different from each other);

(In the formula (2), R ⁵ and R ⁶ each independently represent a saturated alkyl group having 1 to 24 carbon atoms).

[5] The thermoplastic resin film according to [4], wherein the resin composition contains the phenolic antioxidant represented by the formula (1).

[6] The thermoplastic resin film according to [4], wherein the content of the phenolic antioxidant relative to the total amount of the solid content of the resin composition is 0.01 to 2% by mass.

[7] The thermoplastic resin film according to any one of [1], wherein the resin composition further contains a filler and is extended at least in a uniaxial direction.

[8] The thermoplastic resin film according to [7], wherein the filler has a volume average particle diameter of At least one of an inorganic filler of 0.05 to 10 μm and an organic filler having an average dispersed particle diameter of 0.05 to 10 μm.

[9] The thermoplastic resin film according to [7], wherein the resin composition contains the filler in an amount of 5 to 75% by mass based on the total amount of the solid content.

[10] The thermoplastic resin film according to any one of [7], wherein the extension is an extension in a uniaxial direction, and the stretching ratio is 1.3 to 15 times.

[11] The thermoplastic resin film according to any one of [7], wherein the extension is an extension in a biaxial direction, and the stretching ratio is 4 to 80 times in terms of area extension magnification.

[12] The thermoplastic resin film according to any one of [7] to [11], comprising one or more porous thermoplastic resin layers, wherein the porous thermoplastic resin layer is obtained by the following formula (3) The porosity is 5 to 70% by volume;

ρ ₀ : true density of porous thermoplastic resin layer

ρ: density of the porous thermoplastic resin layer.

[13] The thermoplastic resin film according to any one of [1] to [12] wherein the thermoplastic resin contained in the resin composition contains at least one of a polyolefin resin and a polyester resin.

[14] A printing paper using the thermoplastic resin film according to any one of [1] to [13].

[15] A label which is a thermoplastic resin film according to any one of [1] to [13].

[16] A reflector using the thermoplastic resin according to any one of [1] to [13] membrane.

[17] A liquid crystal display device using the reflector described in [16].

[18] A lighting kanban using the reflector as described in [16].

[19] A lighting device using the reflector described in [16].

The thermoplastic resin film according to the present invention is not easily deteriorated even when exposed to light for a long period of time. Therefore, by using the thermoplastic resin film, it is possible to provide a printing paper which can suppress deterioration over time or decrease in light reflectance or label.

Further, since the thermoplastic resin film of the present invention can maintain excellent light reflectance for a long period of time, by using the thermoplastic resin film as a reflector, it is possible to provide a liquid crystal display device, a lighting fixture, and a lighting device which can maintain high brightness for a long period of time.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made in accordance with a representative embodiment of the present invention, but the present invention is not limited to such an embodiment.

Further, the numerical range expressed by "~" in the present specification means a range including the numerical values described before and after "~" as the lower limit and the upper limit.

In the present invention, when referring to "main component" and "main", the main component in the copolymerization refers to a component having the largest amount of molybdenum in the copolymerization monomer, and the main component in the composition is a component. Refers to the most used material in the blended material. The so-called main thermoplastic resin refers to the thermoplastic resin used in the formulated thermoplastic resin.

Also, when referring to "(meth)acrylic acid", it is meant to include both acrylic acid and methacrylic acid. The derivatives of the (meth)acrylic acid, such as a salt, an ester, a guanamine or a copolymer are also the same.

<Composition and Structure of Thermoplastic Resin Film>

The thermoplastic resin film of the present invention has a film layer obtained by molding a resin composition containing a thermoplastic resin, a light stabilizer (1) having a molecular weight of 600 or less, and a light stabilizer (2) having a molecular weight of 650 or more. Hereinafter, the components of the resin composition, the layer constitution of the thermoplastic resin film, the surface treatment, and the molding method will be described.

[Resin composition] (light stabilizer)

The term "light stabilizer" means an organic compound having a function of trapping a radical generated on or in the surface of a thermoplastic resin film into a molecule and deactivating it.

The thermoplastic resin film of the present invention is characterized in that a light stabilizer (1) having a molecular weight of 600 or less and a light stabilizer (2) having a molecular weight of 650 or more are used in combination.

In the prior art, for example, in Patent Documents 5 to 7, the light stabilizers used in the thermoplastic resin film may be used singly or in combination of two or more. However, these prior art specifically do not teach what kind of effect or the like is obtained by what kind of light stabilizer is used in combination.

Moreover, in fact, in the prior art, there is no description of any case in which two or more kinds of light stabilizers (especially HALS) are used in combination, and according to the cited documents, it is not possible to obtain a light stabilizer which selects a specific condition (especially It is the motive of HALS) and the mixing of light stabilizers (especially HALS) that meet specific conditions other than them.

In order to extend the life of the thermoplastic resin film, the inventors of the present invention conducted a detailed investigation on the deterioration mechanism of the thermoplastic resin film hitherto. As a result, it has been found that the light-reflecting surface directly exposed to the light source is deteriorated significantly, and the surface is fine. Crack, discoloration. In particular, it is known that the thermoplastic resin film used as a reflector causes a decrease in light reflectance due to deterioration of such a resin. Based on these facts, it is believed that the low molecular weight of the thermoplastic resin is remarkable on the light-reflecting surface, which is caused by the deactivation of the light stabilizer contained in the portion.

Further, the inventors of the present invention found that the light stabilizer-like additive contributes to the ease of action inside the resin composition when the molecular weight is small in the course of the type or amount of the light stabilizer used in the research. (Easy to seep). And obtained the following structure Thought: By using a low molecular weight light stabilizer in combination with a medium molecular weight or a high molecular weight light stabilizer, the low molecular weight, medium molecular weight or high of the surface of the thermoplastic resin film is utilized in the initial stage of use of the thermoplastic resin film. The molecular weight light stabilizer mainly utilizes a low molecular weight light stabilizer which is easily exuded and gradually oozes out on the printing surface or the back surface and near the light reflecting surface in the middle stage of use, and mainly uses medium molecular weight or high molecular weight in the later stage of use. The light stabilizer can suppress the deterioration of the resin in the vicinity of the light-reflecting surface at any stage, and the life of the thermoplastic resin film can be extended.

Further, according to further studies by the inventors of the present invention, it has been found that in order to achieve a long life of the thermoplastic resin film, it is necessary to use a low molecular weight light stabilizer (1) having a molecular weight of 600 or less and a molecular weight to a high molecular weight having a molecular weight of 650 or more. At least two of the light stabilizers (2) complete the present invention.

Examples of the light stabilizers (1) and (2) which can be used in the thermoplastic resin film of the present invention include HALS (stereoscopic barrier light stabilizer, hindered amine light stabilizer) or benzotriazole light stabilizer. Agent, benzophenone light stabilizer, and the like. Among these, from the viewpoint of higher light stability, it is preferred that either of the light stabilizer (1) or the light stabilizer (2) is HALS, more preferably the light stabilizer (2) is HALS, and further Preferably, the light stabilizer (1) and the light stabilizer (2) are both HALS.

Specific examples of the light stabilizers (1) and (2) which can be used in the thermoplastic resin film include those described in Table 1. However, the light stabilizers (1) and (2) which can be used in the thermoplastic resin film are not limited to the light stabilizers described in Table 1. In addition, these low molecular weight light stabilizers, medium molecular weight light stabilizers, and high molecular weight light stabilizers may be used alone or in combination of two or more.

Among them, as the light stabilizer (1), it is preferred to use any one of 4 and 5 in Table 1, and it is more preferable to use 5. Further, as the light stabilizer (2), it is preferred to use any one of 10, 12, 16, and 18 in Table 1, and it is more preferable to use 16. Further, as a combination of the light stabilizers (1) and (2), a combination of 5 and 16 in Table 1 is preferred.

In order to obtain a thermoplastic resin film excellent in long-term light resistance, the molecular weight of the light stabilizer (1) on the low molecular weight side is 600 or less, preferably 550 or less, more preferably 510 or less. another The light stabilizer (1) on the low molecular weight side preferably has a molecular weight of 300 or more, more preferably 420, from the viewpoint of suppressing volatilization during molding or coloring of the thermoplastic resin film by the deteriorated light stabilizer. the above.

Further, the molecular weight of the light stabilizer (2) on the medium molecular weight to the high molecular weight side is 650 or more, preferably 1,000 or more, and more preferably 2,200 or more. Further, the upper limit of the molecular weight of the photostabilizer (2) is not particularly limited, but is preferably 4,500 or less.

Further, the difference between the molecular weight of the light stabilizer (1) and the light stabilizer (2) contained in the resin composition is preferably 100 or more, more preferably 200 or more, still more preferably 300 or more.

Here, the molecular weight of the polymer when the light stabilizers (1) and (2) contain a polymer is a weight average molecular weight measured by mass spectrometry at a molecular weight of 1000 or less, and a molecular weight of 1,000 or more. In the case of weight average molecular weight as determined by gel permeation chromatography (GPC).

The content of the light stabilizer (1) based on the total amount of the solid content of the resin composition is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, still more preferably 0.06% by mass or more, and particularly preferably 0.1% by mass. %the above. In addition, the content ratio of the light stabilizer (1) to the total amount of the solid content of the resin composition is preferably 1% by mass or less, more preferably 0.8% by mass or less, still more preferably 0.7% by mass or less, and particularly preferably 0.6% by mass or less.

The content of the light stabilizer (2) based on the total amount of the solid content of the resin composition is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, still more preferably 0.06% by mass or more, and particularly preferably 0.1% by mass. %the above. In addition, the content ratio of the light stabilizer (2) to the total amount of the solid content of the resin composition is preferably 1% by mass or less, more preferably 0.8% by mass or less, still more preferably 0.7% by mass or less, and particularly preferably 0.6% by mass or less.

The total content of the light stabilizer (1) and the light stabilizer (2) in the resin composition is preferably 0.2 to 0.8% by mass, more preferably 0.3 to 0.6% by mass based on the total amount of the solid content of the resin composition. .

Further, the mass ratio of the light stabilizer (1) to the light stabilizer (2) is preferably 1:10 to 10: 1, more preferably 1:5 to 5:1, and further preferably 1:3 to 3:1.

In the case where the thermoplastic resin film has a multilayer structure, the resin composition for forming the layer exposed on the surface preferably has a content ratio of the light stabilizer (1) to the total amount of the solid content of 0.01 to 0.6% by mass. Good is 0.1~0.6% by mass. Further, the resin composition for forming the layer which is not exposed on the surface is preferably a content ratio of the light stabilizer (1) to the total amount of the solid content of 0.01 to 0.6% by mass, more preferably 0.01 to 0.5% by mass.

(Antioxidants)

The resin composition used for the thermoplastic resin film preferably further contains an antioxidant in order to suppress deterioration of the thermoplastic resin. The antioxidant has a function of suppressing changes in the thermoplastic resin film due to heat, an oxidizing substance, or ultraviolet rays. Therefore, when the thermoplastic resin film is a reflector, the effect of suppressing a decrease in reflectance is easily exhibited.

Among the antioxidants, the phenolic antioxidant of 2,6-di-t-butyl-4-methylphenol is preferred because it has a high effect of suppressing the change of the thermoplastic resin film, and is preferably used in combination with HALS. . Phenolic antioxidants are often referred to as primary antioxidants because of their direct action. On the other hand, such a phenolic antioxidant has a drawback that it is easily colored if it is oxidized by itself. In particular, when the surface of the thermoplastic resin film is a porous structure, when a phenolic antioxidant is used, the surface tends to be easily colored. Further, when the thermoplastic resin film has a multilayer structure and at least one of the layers contains a porous structure, there is a tendency that the end faces of the film are easily colored.

However, according to the study by the present inventors, it has been found that a phenolic antioxidant having a specific structure represented by the following formula (1) and/or a bis-saturated alkylhydroxylamine represented by the following formula (2) are selected. It is easy to suppress the coloration of these antioxidants themselves.

In view of the fact that the function of maintaining the color tone of the printing paper or the label and effectively suppressing the decrease in the reflectance of the reflector, it is more preferable to use an effect of effectively capturing the radical generated by heat or ultraviolet rays to stabilize the system. A higher phenolic antioxidant represented by the formula (1).

(In the formula (1), any one of R ¹ and R ³ is a hydroxyl group, and the other represents a hydrogen atom. R ² represents an alkyl group having a carbon number of 3 or more. R ⁴ represents a branched alkyl group having 1 to 6 carbon atoms. The base n represents an integer of 1 to 3. When n is 1, L is a substituent. When n is 2 or 3, L is a linking group, and a plurality of R ¹ to R ⁴ may be the same or different.

In the formula (1), R ^{2 is} preferably a third butyl group or a third pentyl group. R ^{4 is} preferably a branched alkyl group having 1 to 5 carbon atoms, more preferably a methyl group, an ethyl group, an isopropyl group, a tert-butyl group or a third pentyl group.

n represents an integer from 1 to 3.

When n is 1, L is a substituent. In this case, as the substituent, a substituted or unsubstituted alkyl group or the like can be used. Preferably, the number of carbon atoms of the alkyl group from which the substituent is removed is from 1 to 20, more preferably from 1 to 10. In the viewpoint of suppressing the coloring of the phenolic antioxidant by itself, a substituent having a phosphate structure represented by the formula (4) and having a function of a secondary antioxidant, or a formula (5) An acryloylphenyl substituted alkyl group represented by a substituent capable of trapping a radical at a position remote from the phenol skeleton. Further, in the formulas (4) and (5), t-Bu is a tertiary butyl.

[Chemical 4]

When n is 2 or 3, L is a linking group. The linking group may, for example, be a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkylene group, a substituted or unsubstituted subring. An alkyl group, a substituted or unsubstituted extended aryl group, a thioether group, a linking group containing an ester bond, and the like. The number of carbon atoms of the alkylene group in which the substituent is removed, the cycloalkyl group in which the substituent is removed, the alkylene group in which the substituent is removed, or the cycloalkylene group in which the substituent is removed is preferably from 1 to 20, more preferably from 1 to 10. . The cycloalkylene or cycloalkylene group may be a spiro structure. Further, the carbon number of the exoaryl group from which the substituent is removed is preferably from 6 to 20, more preferably from 6 to 10. The linking group containing an ester bond may be a group in which a carboxyethyl group or a carboxypropyl group represented by the formula (6) is bonded via a polyoxyethylene chain or a spirodiol.

In the formula (6), m, p and q each independently represent 2 or 3.

Further, the linking group may be symmetrical or asymmetrical. Representative examples of the antioxidant having an asymmetric linking group include 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane (for example, manufactured by ADEKA Corporation). Product name "AO-30").

When L is a linking group in the formula (1), n is preferably 2. The phenolic antioxidant having n of 2 can be represented by the formula (7).

In the formula (7), the description of R ¹ to R ⁴ and L can be referred to the corresponding description of the formula (1). The plurality of R ¹ , R ² , R ³ and R ⁴ may be the same or different from each other. More preferably, the antioxidant represented by the formula (7) has a symmetrical structure, that is, two R ¹ to R ⁴ are identical to each other. Thereby, deterioration of the thermoplastic resin can be effectively suppressed.

Specific examples of the phenolic antioxidant represented by the formula (1) include those described in Table 2. Among these phenolic antioxidants, it is preferred to use the antioxidants of 4 and 8 to 10 in Table 2. However, the antioxidant which can be used is not limited to the antioxidant described in Table 2. Further, these antioxidants may be used alone or in combination of two or more.

Further, as the antioxidant, a bis-saturated alkylhydroxylamine represented by the following formula (2) can also be preferably used.

In the formula (2), R ⁵ and R ⁶ are each independently a saturated alkyl group having 1 to 24 carbon atoms. R ⁵ and R ⁶ are each independently a saturated alkyl group having 8 to 24 carbon atoms, more preferably a saturated alkyl group having 12 to 18 carbon atoms. The bis-saturated alkylhydroxylamine can be produced, for example, by the action of hydrogen peroxide on an amine obtained by using reduced type tallow as a raw material.

Representative examples of the bis-saturated alkylhydroxylamine represented by the formula (2) include N,N-dioctadecylhydroxylamine, CAS. No. [143925-92-2], and trade name "Irgastab FS042". (Manufactured by BASF Corporation of Japan). Such an antioxidant is mainly composed of a octadecyl group having a carbon number of 18 and a bis-saturated alkylhydroxylamine having R ⁵ and R ⁶ as a main component. Further, such a bis-saturated alkylhydroxylamine may also be referred to as a primary antioxidant which can directly stabilize the resin composition.

The resin composition is preferably contained in an amount of 0.01% by mass or more based on the total amount of the solid content component, more preferably 0.02% by mass or more, and still more preferably 0.05% by mass or more. When the content of the antioxidant in the resin composition is 0.01% by mass or more, oxidative degradation of the thermoplastic resin by the oxidizing gas is effectively suppressed, and the coloring or light reflectance of the film due to deterioration of the resin is easily suppressed. The tendency to decline. In the same manner, the resin composition is preferably contained in an amount of 2% by mass or less based on the total amount of the solid content component, more preferably 1.5% by mass or less, and still more preferably 1% by mass or less. When the content of the antioxidant in the resin composition is 2% by mass or less, the coloring of the film by the antioxidant is easily lowered.

When the thermoplastic resin film contains one or more layers having a porous structure, if the porous layer contains an antioxidant, the coloring of the film or the decrease in the light reflectance can be effectively suppressed. However, it is possible to use an antioxidant even in other layers.

The thermoplastic resin film may also contain both the above antioxidant and secondary antioxidant. Thereby, the effect of suppressing the coloring of the above-mentioned antioxidant (primary antioxidant) itself is exerted. Examples of the secondary antioxidant include a phosphorus-based antioxidant, an amine-based antioxidant, and a sulfur-based antioxidant. Moreover, the content of the secondary antioxidant in the resin composition is preferably 0.001% by mass or more, and more preferably 0.1% by mass or more based on the total amount of the solid content of the resin composition. In addition, the amount of the secondary antioxidant added to the resin composition is preferably 1% by mass or less, and more preferably 0.4% by mass or less based on the total amount of the solid content of the resin composition.

(thermoplastic resin)

The thermoplastic resin used in the thermoplastic resin film of the present invention is a substrate for forming a film, and the kind thereof is not particularly limited. Examples of the thermoplastic resin used in the thermoplastic resin film include polyolefin resins such as an ethylene resin, a propylene resin, a polymethyl-1-pentene, and an ethylene-cyclic olefin copolymer; and nylon-6 and nylon- 6,6, nylon-6,10, nylon-6,12 and other polyamine resin; including polyethylene terephthalate or its copolymer, polyethylene naphthalate, polybutylene terephthalate a polyester resin such as an aromatic polyester such as a diester, a polybutylene succinate or an aliphatic polyester such as polylactic acid; a styrene resin such as polycarbonate, atactic polystyrene or syndiotactic polystyrene; Polyphenylene sulfide. These may be used alone or in combination of two or more.

Among these, a polyolefin resin or a polyester resin is preferably used, and a polyolefin resin is more preferably used. Among the polyolefin resins, an ethylene resin or a propylene resin is preferably used.

In the case of a thermoplastic resin film using a polyolefin resin, the color change (yellowing) caused by ultraviolet light from the light source is smaller than that of the polyester resin, and particularly in the reflector, there is a long-term use. The light reflectance is also less prone to decline. On the other hand, the film of the polyester resin tends to be less stretched or deformed by heat from the light source, and thus tends to be easily applied to a larger printing paper or a built-in light source.

As the vinyl resin, high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, or ethylene as a main component, 1-butene, 1-hexene, 1-heptene, or the like can be used. A copolymer of an α-olefin such as 4-methyl-1-pentene.

As the propylene-based resin, a copolymer of propylene homopolymer or propylene as a main component and an α-olefin such as ethylene, 1-butene, 1-hexene, 1-heptene or 4-methyl-1-pentene can be used. Things. The stereoregularity is not particularly limited, and those who exhibit isotactic or syndiotactic and various degrees of stereoregularity can be used. Further, the copolymer may be a ternary system, a ternary system, or a quaternary system, or may be a random copolymer or a block copolymer.

Further, as the vinyl resin or the propylene resin, a functional group-containing polyolefin tree can be used. The functional group-containing polyolefin resin is obtained by appropriately selecting one or two or more kinds of monomers containing functional groups such as the following monomers: vinyl acetate, vinyl alcohol, vinyl propionate , carboxylic acid of vinyl butyrate, vinyl pivalate, vinyl hexanoate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl butyl benzoate, vinyl cyclohexane carboxylate Vinyl esters; (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, (A) (meth) acrylates such as dicyclopentanyl acrylate, (meth) acrylamide, N-methylol (meth) acrylamide; methyl vinyl ether, ethyl vinyl ether, propyl ethylene Vinyl ethers such as ether, butyl vinyl ether, cyclopentyl vinyl ether, cyclohexyl vinyl ether, benzyl vinyl ether, and phenyl vinyl ether.

Further, the polyolefin-based resin and the functional group-containing polyolefin-based resin may be modified by grafting as needed. A known method can be used for the graft modification. Specific examples include graft modification using an unsaturated carboxylic acid or a derivative thereof. Examples of the unsaturated carboxylic acid include (meth)acrylic acid, maleic acid, fumaric acid, and itaconic acid. Further, examples of the derivative of the unsaturated carboxylic acid include an acid anhydride, an ester, a decylamine, a quinone imine, and a metal salt. Specific examples of the derivative of the unsaturated carboxylic acid include maleic anhydride, itaconic anhydride, citraconic anhydride, methyl (meth)acrylate, ethyl (meth)acrylate, and (methyl). Butyl acrylate, glycidyl (meth)acrylate, monoethyl maleate, diethyl maleate, monomethyl fumarate, dimethyl fumarate, y Monomethyl formic acid, diethyl itaconate, (meth) acrylamide, monodecyl maleate, diammonium maleate, maleic acid-N-monoethyl Indoleamine, maleic acid-N,N-diethylguanamine, maleic acid-N-monobutylamine, maleic acid-N,N-dibutylguanamine, anti Butenoic acid monodecylamine, dimethyl fumarate, fumaric acid-N-monoethyl decylamine, fumaric acid-N,N-diethyl decylamine, anti-butene Diacid-N-monobutyl hydrazine Amine, fumaric acid-N,N-dibutylguanamine, maleimide, N-butyl maleimide, N-phenyl maleimide, (A) Sodium acrylate, potassium (meth) acrylate, and the like. The graft modified product is graft-modified with a polyolefin resin and a functional group-containing polyolefin resin by adding a grafting monomer of usually 0.005 to 10% by mass, preferably 0.01 to 5% by mass. By.

The resin composition and the thermoplastic resin film obtained by molding the resin composition are easy to handle by extending the resin composition into a film shape, and imparting physical strength such as rigidity to the obtained thermoplastic resin film. In particular, it is preferably contained in an amount of 25% by mass or more based on the total amount of the solid content component, more preferably 35% by mass or more, and still more preferably 45% by mass or more. On the other hand, the resin composition and the resin composition are formed from the viewpoint of easily controlling the porosity or easily controlling the opacity of the substrate, particularly in the reflector, which is easy to achieve a high light reflectance. The thermoplastic resin film preferably contains 99.5% by mass or less of the thermoplastic resin based on the total amount of the solid content component, more preferably 95% by mass or less, further preferably 85% by mass or less, and particularly preferably 80% by mass or more. the following.

In the case where the thermoplastic resin film is composed of a plurality of layers, the extrusion molding and the stretching process are easy, and from the viewpoint of imparting mechanical strength to the obtained thermoplastic resin film, it is preferable to exceed the total thickness of the thermoplastic resin film. 30% or more of the layers contain 25% by mass or more of the thermoplastic resin, more preferably 35% by mass or more, and still more preferably 45% by mass or more. On the other hand, it is preferable that one or more layers which are more than 30% of the total thickness of the thermoplastic resin film contain 99% or less of the thermoplastic resin, more preferably 95% by mass or less, and still more preferably 80% by mass or less. It is particularly preferable to contain 70% by mass or less.

In addition, as described in the following [Structural Structure of Thermoplastic Resin Film], the content of one or more thermoplastic resins may be less than 25% by mass in a thickness of 30% or less of the total thickness of the thermoplastic resin film. a layer or a layer exceeding 95% by mass as another functional layer (for example, a gloss adjustment layer, a gas barrier layer, a light diffusion layer, an open line prevention layer, an easy adhesion layer, and an easy layer) Destruction layer, etc.). The layer may be a layer exposed on the surface of the thermoplastic resin film or an inner layer not exposed on the surface of the thermoplastic resin film.

(filler)

The thermoplastic resin film preferably contains a filler as a nucleating agent for forming pores therein or as a high refractive index material. The above fillers can also function as both a nucleating agent and a high refractive index material. The filler used herein may be an inorganic filler or an organic filler, preferably a filler which can form pores upon stretching, or a filler which imparts mechanical strength to the thermoplastic resin film as a filler.

Specific examples of the inorganic filler include heavy calcium carbonate, precipitated calcium carbonate, calcined clay, talc, titanium oxide, barium sulfate, aluminum sulfate, cerium oxide, zinc oxide, magnesium oxide, diatomaceous earth, and titanium. Sour and so on. Further, a surface-treated product obtained by subjecting the above inorganic filler to surface treatment with various surface treatment agents can also be exemplified. Among the inorganic fillers, the heavy calcium carbonate, the precipitated calcium carbonate, and the surface-treated products, clay, and diatomaceous earth are preferred because they have a low porosity and good hole formation property when extended. Further, titanium oxide, such surface-treated products, barium titanate or the like are preferred because they have a high refractive index and a high whiteness and a high light reflectance. Further preferably, the inorganic filler is heavy calcium carbonate, precipitated calcium carbonate, and titanium oxide which have been surface-treated with various surface treatment agents.

Examples of the surface treatment agent for the inorganic filler include an acid such as a resin acid, a petroleum resin acid, or an organic acid, a salt such as sodium, potassium or ammonium of the acid, or an ester of the acid; a sulfate type anionic surfactant; Sulfonic acid type anionic surfactant; nonionic surfactant; wax, paraffin; diene polymer; various coupling agents; inert inorganic oxide.

Here, specific examples of the organic acid include hexanoic acid, caprylic acid, capric acid, capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, and oleic acid. Fatty acids such as linoleic acid, linoleic acid, and tungstic acid or maleic acid or hexadienoic acid.

Specific examples of the above sulfate type anionic surfactant include long chain An alcohol sulfate, a polyoxyethylene alkyl ether sulfate, a sulfated oil, or the like, or a salt such as sodium or potassium. Specific examples of the sulfonic acid type anionic surfactant include alkylbenzenesulfonic acid, alkylnaphthalenesulfonic acid, paraffin sulfonic acid, α-olefin sulfonic acid, alkylsulfosuccinic acid, and the like, or the like. Potassium and other salts.

Examples of the nonionic surfactant include fatty acid esters such as alkyl diols, polyalkylene glycols, glycerin, monosaccharides, and disaccharides.

Examples of the diene polymer include polybutadiene and isoprene.

Examples of the various coupling agents include titanate coupling agents, aluminate coupling agents, and decane coupling agents.

Examples of the inert inorganic oxide include alumina and cerium oxide.

Among these, an organic acid, an organic acid ester, an organic acid salt, an anionic surfactant, a nonionic surfactant, a decane coupling agent, and an inert inorganic oxide are preferable.

These surface treatment agents may be used alone or in combination of two or more. As a surface treatment method of the inorganic filler using the surface treatment agent, for example, Japanese Patent Laid-Open No. Hei 5-43815, Japanese Patent Laid-Open Publication No. Hei No. Hei No. Hei No. Hei. Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. The method described in JP-A-2002-665443, JP-A-2010-66512, and the like.

As the organic filler, particles of a thermoplastic resin or a thermosetting resin having a melting point or a glass transition point higher than a melting point or a glass transition point of a main thermoplastic resin constituting the thermoplastic resin film can be preferably used. For example, when a propylene-based resin is used as the main thermoplastic resin constituting the thermoplastic resin film, specific examples of the organic filler include polyethylene terephthalate, polybutylene terephthalate, and polyfluorene. Amine, polycarbonate, polynaphthalene Ethylene glycol diester, polystyrene, melamine resin, cyclic olefin homopolymer, ethylene-cyclic olefin copolymer, polyethylene sulfide, polyimide, polyethyl ether ketone, polyphenylene sulfide, and the like. Since the melting point or the glass transition point is higher than the propylene-based resin which is the main thermoplastic resin constituting the film, and is incompatible with the propylene-based resin, the pore formation property at the time of film extension is good, which is preferable. Further, in the case where the organic filler is a thermoplastic resin, it is also preferred to crosslink the thermoplastic resin from the viewpoint of increasing the melting point or the glass transition point.

The thermoplastic resin film may be used singly or in combination of two or more kinds selected from the group consisting of inorganic fillers and organic fillers. When two or more types are used in combination, the void forming nucleating agent may be used in combination with the high refractive index material, or the organic filler may be mixed with the inorganic filler.

The volume average particle diameter of the inorganic filler or the average dispersed particle diameter of the organic filler affects the reinforcing effect of the thermoplastic resin film or the pore size caused by the stretching. In order to adjust these characteristics, the volume average particle diameter of the inorganic filler and the average dispersed particle diameter of the organic filler are preferably 0.01 μm or more, more preferably 0.05 μm or more, and still more preferably 0.1 μm or more. In particular, when a filler having an average particle diameter or an average dispersed particle diameter of 0.1 μm or more, preferably 0.5 μm or more is used, voids are not obtained by extension molding. On the other hand, the volume average particle diameter of the inorganic filler or the average dispersed particle diameter of the organic filler is preferably 10 μm or less, more preferably 5 μm or less, further preferably 1.5 μm or less, and particularly preferably 1.3 μm or less. When a filler having an average particle diameter or an average dispersed particle diameter of 10 μm or less, preferably 4 μm or less is used, there is a tendency that an independent uniform pore is easily formed. In particular, when a filler having an average particle diameter or an average dispersed particle diameter of 1.5 μm or less, preferably 0.8 μm or less, and more preferably 0.5 μm or less is used, there is a void which is particularly easy to obtain a size which allows visible light to be efficiently reflected. tendency.

The volume average particle diameter of the inorganic filler and the volume average particle diameter when the organic filler is a particle of a thermosetting resin can be measured by a laser diffraction method. As a laser Specific examples of the diffraction method include the Microtrac method.

When an inorganic filler is extracted from a resin composition containing an inorganic filler or a thermoplastic resin film for measurement, a resin composition or a thermoplastic resin film of a sample may be used in accordance with JIS P 8251:2003 "Paper, Paperboard, and Pulp - The method specified in the ash test method - 525 ° C combustion method burns the resin to extract an inorganic filler.

When the average particle diameter of the inorganic filler and the average dispersed particle diameter of the organic filler present in the resin composition or the thermoplastic resin film are determined, the resin composition or the thermoplastic resin film of the sample can be cut using a microtome or the like. The cross section was observed by a scanning electron microscope, at least 20 monodisperse particles were selected from the observed image, and the primary particle diameter of each particle was calculated by image analysis, and the average value thereof was defined as the average particle diameter of the inorganic filler and the organic filler. Average dispersed particle size.

The resin composition of the molded thermoplastic resin film preferably contains at least one of the above inorganic filler and organic filler in an amount of 0.5% by mass or more based on the total amount of the solid content of the resin composition, more preferably 5% by mass or more, and further It is preferably 15% by mass or more, and more preferably 20% by mass or more. When the content of the filler in the resin composition is 0.5% by mass or more, the reinforcing effect of the thermoplastic resin film is easily obtained, and if it is 5% by mass or more, it is easy to achieve a high whiteness, a high opacity, and a high The tendency of light reflectivity. On the other hand, the resin composition of the formed film layer is preferably the total amount of the solid content relative to the resin composition from the viewpoint of uniformly dispersing the inorganic filler or the organic filler in the thermoplastic resin film and the surface is not easily damaged. Further, at least one of the inorganic filler and the organic filler containing 75% by mass or less is more preferably 65% by mass or less, and still more preferably 55% by mass or less. In the case where the inorganic filler is used in combination with the organic filler, it is preferred to set the blending amount of each filler so that the total amount of the inorganic filler and the organic filler is the above-described content.

In the case where the thermoplastic resin film has a multilayer structure, it is preferred to form a resin composition of a layer constituting more than 30% of the total thickness of the thermoplastic resin film with respect to the total amount of the solid content component. The filler is contained in an amount of 1% by mass, more preferably 5% by mass or more, further preferably 15% by mass or more, and particularly preferably 20% by mass or more. On the other hand, it is preferable that the resin composition in which the layer constituting the total thickness of the thermoplastic resin film is more than 30% is contained in an amount of 75% by mass or less based on the total amount of the solid content component, and more preferably 65% by mass or less. Further, it is preferably contained in an amount of 55% by mass or less.

(other ingredients)

In the resin composition, an additive such as a dispersant or a lubricant or a fluorescent whitening agent may be formulated as needed.

Specific examples of the dispersant include a decane coupling agent, a higher fatty acid such as oleic acid or stearic acid, a metal soap, poly(meth)acrylic acid, polymethacrylic acid, or the like. The dispersibility of the inorganic filler and the organic filler is improved by the addition of the dispersant. The content of the dispersant relative to the total amount of the solid content of the resin composition is preferably from 0.01% by mass to 4% by mass.

Specific examples of the fluorescent whitening agent include the product name "Tinopal OB" (manufactured by BASF Corporation of Japan), the product name "Hakkol STR" (manufactured by Showa Chemical Industry Co., Ltd.), and the product name "Hakkol STB" (Showa Chemical Industry). The company is manufactured under the trade name "Kayalight OS" (manufactured by Nippon Kayaku Co., Ltd.). The content of the fluorescent whitening agent relative to the total amount of the solid content of the resin composition is preferably 0.001% by mass to 0.1% by mass.

In the case where the main thermoplastic resin constituting the thermoplastic resin film is a propylene-based resin, in order to improve the stretchability, it may be contained in an amount of 0% by mass or more and 25% by mass or less based on the total amount of the solid content of the resin composition. A resin having a melting point lower than that of the propylene-based resin such as ethylene or ethylene vinyl acetate.

When the thermoplastic resin film has a multilayer structure, it is preferable that the low melting point resin is contained in one or more layers exceeding 30% of the total thickness of the thermoplastic resin film. Thereby, even if the resin having no low melting point is contained in the other layer, the overall elongation of the thermoplastic resin film is easily improved. The resin having a low melting point is more than 30% of the total thickness of the thermoplastic resin film. The content in the upper layer is preferably in a range of 0.5% by mass or more and 25% by mass or less based on the total amount of the solid content of the layer, and does not exceed the blending amount of the propylene-based resin.

[Layer composition of thermoplastic resin film]

The structure of the thermoplastic resin film may be a single layer structure composed of a single layer of a film layer, or a multilayer structure in which a plurality of layers are laminated. In the case of a multilayer structure, the combination of the composition of the resin composition and the film forming method can be applied to the layer existing on the surface of the thermoplastic resin film and the inner layer of the thermoplastic resin film. Characteristic features. In the multilayer thermoplastic resin film, all of the layers may contain the light stabilizer (1) and the light stabilizer (2), or a part of the layer may contain the light stabilizer (1) and the light stabilizer (2). In the case where a part of the layer contains the light stabilizer (1) and the light stabilizer (2), it is preferred that the layer be the layer constituting the outermost surface.

Further, when the thermoplastic resin film is used for printing paper or a label, a layer for imparting ink adhesion or paper discharge property at the time of printing can be provided on the outermost layer. Further, when the thermoplastic resin film is used for a reflector, it may be a single layer of a layer which serves as a light-reflecting function, or a layer of more than 30% of the total thickness. The material layer is provided with a light reflecting function, and a multilayer structure of another functional layer (for example, a protective layer, a light diffusion layer, a bright line preventing layer, a gas barrier layer, or the like) is laminated on at least one surface of the substrate layer.

As a specific example of the other functional layer, for example, the protective layer is described in Japanese Laid-Open Patent Publication No. 2005-031653. For example, the light-diffusing layer is described in Japanese Patent Laid-Open Publication No. Hei. No. 2006-018244, for example, a clear line preventing layer. Japanese Patent Publication No. 2007-148391, Japanese Patent Laid-Open No. 2010-049231, Japanese Patent Laid-Open No. 2010-085843, Japanese Patent Laid-Open No. 2011-200337, and Japanese Patent Laid-Open No. 2012-158167 The person who is listed in the bulletin.

In either case, the layer which becomes the outermost surface preferably contains the above light stabilizer, and more preferably contains the above light stabilizer and antioxidant.

[Surface Treatment of Thermoplastic Resin Film]

The surface of the thermoplastic resin film can be subjected to surface treatment in order to impart antistatic properties or printability. Regarding the surface treatment, it is not easy to cause trouble in the printing step by imparting antistatic properties, thereby improving handleability, and improving the adhesion between the surface of the thermoplastic resin film and the printing ink. As a result, the thermoplastic resin film is suitable for a variety of printing methods.

The surface treatment is preferably carried out by a step of coating and drying the surface oxidation treatment and the surface treatment agent.

The surface treatment agent preferably contains 0.1 to 100% by mass of an antistatic agent, 0 to 99.9% by mass of a polymer binder, and 0 to 70% by mass of pigment particles, based on the total solid content ratio of the surface treatment agent. More preferably, it contains 0.5 to 70% by mass of an antistatic agent, 30 to 99.5% by mass of a polymer binder, and 0 to 69.5% by mass of pigment particles, and further preferably contains 1 to 50% by mass of an antistatic agent, 50 ~99% by mass of polymer binder and 0 to 49% by mass of pigment particles.

(antistatic agent)

The antistatic agent is added to the surface treatment agent in order to impart antistatic properties to the surface of the thermoplastic resin film. Specific examples of the antistatic agent include low molecular weight such as stearic acid monoglyceride, alkyl diethanolamine, sorbitan monolaurate, alkylbenzenesulfonate, and alkyl diphenyl ether sulfonate. Organic compound antistatic agent; conductive inorganic filler such as ITO (indium-doped tin oxide), ATO (antimony-doped tin oxide), graphite whisker, colloidal alumina, alumina-coated colloidal cerium oxide; polythiophene, polypyrrole a so-called electronically conductive polymer that exhibits conductivity by π-electrons in a molecular chain, a nonionic polymer-based antistatic agent such as polyethylene glycol or polyoxyethylene diamine; and a polyvinyl benzyl group; a quaternary ammonium salt type copolymer such as trimethylammonium chloride or polydimethylaminoethyl methacrylate quaternary compound, and an alkali metal ion added to the epoxy group-containing and/or hydroxyl group-containing polymer A polymer containing an alkali metal salt such as a compound.

When the thermoplastic resin film is a printing paper, the polymer having an antistatic function has less influence on the adhesion and transferability of the ink, and the antistatic effect is more persistent. It is high and has almost no coloration, so it is preferred among antistatic agents. Further, among them, the quaternary ammonium salt type copolymer or the alkali metal salt-containing polymer has good antistatic property and is less affected by the antistatic property due to environmental humidity, and thus is more preferable.

The quaternary ammonium salt type copolymer: As an example of the polymer having an antistatic function, a polycationic water-soluble polymer containing a quaternary ammonium salt type copolymer may be mentioned. The copolymer is a quaternary ammonium salt type copolymer containing a quaternary ammonium salt type structural unit (a) represented by the following formula (8) and a hydrophobic structural unit represented by the following formula (9) (b) And the structural unit (c) derived from the monomer copolymerizable with the above, and the mass ratio of the structural units is (a): (b): (c) = 30 to 70: 30~ A range of 70:0 to 40 (% by mass), and a quaternary ammonium salt type copolymer obtained by copolymerization.

The mass ratio of each structural unit (a), (b) and (c) is preferably 35 to 65:35 to 65:0 to 20 (% by mass), and more preferably 40 to 60:40 to 60:0 to 10 (quality%).

Quaternary ammonium salt type structural unit (a)

In the copolymer, the quaternary ammonium salt type monomer which forms the structural unit (a) is an ester of (meth)acrylic acid or a guanamine having a terminal structure represented by the following formula (8). The unit contributes to the antistatic function of the copolymer by having more than one cation in the molecular structure. In order to impart a sufficient antistatic effect, it is preferred that the structural unit (a) in the copolymer be 30% by mass or more. Further, in order to reduce the lithographic suitability without excessively water-soluble, or to prevent adhesion under high humidity conditions, it is preferred that the structural unit (a) in the copolymer be 70% by mass or less.

[化8]

In the formula (8), A represents an ester bond (-COO-), a guanamine bond (-CONH-) or a single bond. R ⁷ represents a hydrogen atom or a methyl group, R ⁸ represents an alkylene group having a carbon number of 2 to 4 or a 2-hydroxyl-propyl group (-CH ₂ CH(OH)-CH ₂ -), and R ⁸ may be adjacent thereto. The two A bonds to form an annular structure. R ⁹ to R ¹² each independently represent an alkyl group having 1 to 3 carbon atoms, and R ¹³ represents an alkyl group having 1 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms. X represents a residue of a chlorine atom, a bromine atom, an iodine atom or a quaternizing agent. R represents an integer from 0 to 3.

In the copolymer, the quaternary ammonium salt type monomer represented by the formula (8) which forms the structural unit (a) can be obtained by using 3-chloro-2-hydroxypropyldimethylamine, 3- a modifier such as chloro-2-hydroxypropyltrimethylammonium chloride or a quaternizing agent such as dimethylsulfuric acid or methyl iodide, or dimethylaminoethyl (meth)acrylate or (methyl) a monomer containing a tertiary amine such as diethylaminoethyl acrylate and dimethylaminopropyl (meth) acrylamide, dimethylallylamine or methyl diallylamine Modified before or after polymerization.

Hydrophobic structural unit (b)

In the copolymer, the structural unit forming the structural unit (b) is an ester of (meth)acrylic acid represented by the formula (9) or a decylamine. This structural unit imparts lipophilicity (reduction of hydrophilicity) to the copolymer, and contributes to water resistance or transfer ink transferability of the thermoplastic resin film containing the same. From the viewpoint of coexistence of antistatic property and printability, it is preferred to copolymerize the structural unit of the above (a) with the structural unit of the above (b), and the structural unit (b) in the copolymer has 30 masses. %the above. Further, in order to obtain the antistatic effect obtained by the structural unit (a), it is preferred The structural unit (b) in the copolymer is present in an amount of 70% by mass or less.

(wherein A represents an ester bond (-COO-) or a guanamine bond (-CONH-). R ¹⁴ represents a hydrogen atom or a methyl group. R ¹⁵ represents an alkyl group having 1 to 30 carbon atoms and a carbon number of 7~ 22 aralkyl groups, or a cycloalkyl group having a carbon number of 5 to 22)

Specific examples of the monomer which forms the structural unit represented by the above formula (9) include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and (methyl). Isobutyl acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, (meth)acrylic acid A (meth)acrylic acid alkyl ester such as a tridecyl ester or a stearyl (meth) acrylate.

Other structural units (c)

In the copolymer, specific examples of the monomer which forms the other structural unit (c) copolymerizable with the above structural unit (a) and the structural unit (b) include styrene, vinyl toluene, and vinyl acetate. A hydrophobic monomer such as a vinylpyrrolidone or a (meth)acrylamide. These monomers may be preferably incorporated as a structural unit (c) into a quaternary ammonium salt type copolymer. This unit facilitates the copolymerization of the copolymer and adjusts the solubility in the solvent when the coating liquid is adjusted.

As the copolymerization method for obtaining the above copolymer, a known polymerization method such as bulk polymerization, solution polymerization or emulsion polymerization using a radical initiator can be employed. Among these, a preferred polymerization method is a solution polymerization method, which is carried out by dissolving each monomer in a solvent, adding a radical polymerization initiator thereto, and flowing under a nitrogen stream. Heat and stir. The solvent is preferably water or an alcohol such as methanol, ethanol, isopropanol or cellosolve. Further, several solvents may be used in combination. As the polymerization initiator, a peroxide such as benzamidine peroxide, a peroxide such as laurel, a azo compound such as azobisisobutyronitrile or azobisvaleronitrile can be preferably used. The concentration of the monomer solid content during the polymerization is usually from 10 to 60% by mass, and the concentration of the polymerization initiator is usually from 0.1 to 10% by mass based on the monomer. The molecular weight of the quaternary ammonium salt type copolymer can be prepared according to polymerization conditions such as polymerization temperature, polymerization time, type and amount of polymerization initiator, solvent usage amount, chain transfer agent and the like.

The molecular weight of the quaternary ammonium salt type copolymer is usually in the range of from 1 to 1,000,000, preferably from 1 to 500,000, as measured by gel permeation chromatography (GPC).

Polymer containing an alkali metal salt: Another example of a polymer having an antistatic function is a polymer containing an alkali metal salt. The alkali metal salt-containing polymer contains the polyalkylene oxide compound structural unit (d) represented by the formula (10), the hydrophobic monomer structural unit (b) represented by the above formula (9), and The above structural unit (c) of the copolymerized monomers, and the mass ratio of the structural units is set to (d): (b): (c) = 1 to 99: 0 to 99: 0 to 40 ( The range of mass %), the copolymer obtained by copolymerization.

The mass ratio of each structural unit (d), (b), and (c) is preferably 20 to 70:30 to 80:0 to 20 (% by mass), and more preferably 30 to 60:40 to 70:0 to 10 (quality%).

Polyalkylene oxide compound structural unit (d)

In the copolymer, the polyalkylene oxide compound monomer forming the structural unit (d) is an alkoxylate of (meth)acrylic acid represented by the formula (10) or a decylamine. The structural unit is a component which contributes to the antistatic function of the alkali metal salt-containing polymer by an anion and an alkali metal ion in the structure. From the viewpoint of exhibiting an antistatic effect, it is preferred that the structural unit (d) in the polymer is 1% by mass or more. Further, in order to reduce the lithographic suitability without excessively becoming water-soluble or to adhere without being subjected to high humidity, the structural unit in the polymer is preferred. (d) It is 99% by mass or less.

(wherein R ¹⁶ represents a hydrogen atom or a methyl group, and R ¹⁷ represents a hydrogen atom, a chlorine atom or a methyl group. A represents a linking group selected from the group <1> below, or is selected from the group <1 below) A linking group or a single bond in which one or more of the linking groups are alternately bonded to one or more of the following <2 groups>. M represents an alkali metal ion. s represents an integer of 1 to 100. .

<1 group> an alkylene group having 1 to 6 carbon atoms which may have a substituent or a 6 to 20 carbon extended group having a substituent

<2 group>-CONH-, -NHCO-, -OCONH-, -NHCOO-, -NH-, -COO-, -OCO-, -O-)

Examples of the alkylene group having 1 to 6 carbon atoms of the <1 group> include a methylene group, an exoethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. These may be linear. It may be branched, preferably linear. Examples of the substituent include a hydroxyl group, an aryl group and the like. Examples of the aryl group having 6 to 20 carbon atoms include a stretching phenyl group, a stretching naphthyl group, and a stretching group. Examples of the substituent include a hydroxyl group, an alkyl group, and the like. Examples of the alkyl group-substituted aryl group include a tolyl group and a xylylene group.

Moreover, as a linking group selected from <2 group>, a urethane group or an ester group is preferable.

Specific examples of the polyalkylene oxide compound monomer forming the structural unit (d) can be listed Lift: (poly) ethylene glycol (meth) acrylate, (poly) propylene glycol (meth) acrylate, (poly) chloroethylene glycol (meth) acrylate, (poly) tetramethylene glycol ( (poly)alkylene oxide (meth) acrylate such as methyl acrylate, methoxy (poly)ethylene glycol (meth) acrylate, methoxy (poly) propylene glycol (meth) acrylate.

Moreover, in these specific examples, an alkylene oxide monomer having a linking group other than a single bond in the portion corresponding to A in the above formula (10) may be mentioned. For example, a compound described in JP-A-H09-113704 can be used as a compound having a urethane bond on A.

Examples of the alkali metal ion in the above formula (10) include lithium, sodium, and potassium ions. Among them, lithium ions having a small ionic radius are preferable. In addition, the alkali metal ion concentration on the surface of the thermoplastic resin film is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more from the viewpoint of obtaining an antistatic effect. On the other hand, from the viewpoint of maintaining adhesion to the printing ink, it is preferably 0.70% by mass or less, and more preferably 0.50% by mass or less.

The alkali metal salt-containing polymer can be obtained by using the polyalkylene oxide compound structural unit (d) represented by the above formula (10), the hydrophobic monomer structural unit (b) represented by the above formula (9), and It is produced by copolymerization with other structural units (c) of the above-mentioned copolymerization.

The method for producing the alkali metal salt-containing polymer is not particularly limited, and a known polymerization method may be used alone or a known polymerization method may be appropriately used in combination, and it is preferred to use a bulk polymerization using a radical initiator. A known polymerization method such as solution polymerization or emulsion polymerization.

As the polymerization method, a solution polymerization method using an inert organic solvent under a nitrogen stream is preferred, and a fat-soluble radical initiator such as an organic peroxide or azonitrile is preferably used.

The molecular weight of the alkali metal salt-containing polymer is preferably in the range of from 10,000 to 1,000,000 by weight average molecular weight as measured by gel permeation chromatography (GPC). When the molecular weight is 10,000 or more, the polymer does not easily bleed out from the coating layer of the surface treatment agent to be formed, and thus it is easy to obtain sufficient water resistance. If the molecular weight is less than 1 million, it is easy to stick The mixture components are mixed, and there is a tendency that coating defects are less likely to occur and a uniform antistatic effect is easily obtained.

(polymer binder)

In the surface treatment agent, in order to have adhesion to the surface layer of the thermoplastic resin film and to improve adhesion to the printing ink, it is preferred to contain a polymer binder of 0 to 99.9% by mass.

Specific examples of the polymer binder include polyethyleneimine, alkyl-modified polyethyleneimine having a carbon number of 1 to 12, poly(ethyleneimine-urea), and poly(ethyleneimine-urea). a polyethyleneimine polymer such as an ethyleneimine adduct, a polyamine polyamine, an ethyleneimine adduct of a polyamine polyamine, and an epichlorohydrin adduct of a polyamine polyamine; an acrylate Copolymer, methacrylate copolymerization, decylamine-acrylate copolymer, decylamine-acrylate-methacrylate copolymer, derivatives of polypropylene decylamine and Acrylate polymer such as oxazolyl acrylate polymer; polyvinylpyrrolidone, polyethylene glycol, vinyl acetate resin, urethane resin, polyether resin, polyester resin, urea resin , terpene resin, petroleum resin, ethylene-vinyl acetate copolymer, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinylidene chloride resin, vinyl chloride-vinylidene chloride copolymer resin, vinyl chloride resin A chloropropene resin, a butyral resin, a polyoxyxylene resin, a nitrocellulose resin, a styrene-acrylic copolymer resin, a styrene-butadiene copolymer resin, an acrylonitrile-butadiene copolymer, or the like.

In the surface treatment agent, the polymer binders may be separately formulated, or two or more of the polymer binders may be mixed and formulated. The polymer binders are preferably dilutable or dispersed in an organic solvent or water. Among these, urethane resin such as polyethyleneimine, alkyl-modified polyethyleneimine, polyether urethane, polyester polyurethane, urethane acrylate or the like The acrylate copolymer has good phase (compatibility) with the polymer having an antistatic function of the above ionic polymer, and is preferable because it is miscible and stable in coating and easy to apply.

(pigment particles)

In the surface treatment agent, the fixing property of the printing ink due to the oil absorption property is improved, the texture or glossiness of the surface is improved as a body pigment, the whiteness is improved as a white pigment, and the adhesion is enhanced by imparting surface irregularities. The performance is improved, and the performance as a UV-reflecting material, such as light resistance or weather resistance, may be 0 to 70% by mass of pigment particles.

As the pigment particles, organic or inorganic fine powders can be used, and specific examples thereof include cerium oxide, calcium carbonate, calcined clay, titanium oxide, zinc oxide, barium sulfate, diatomaceous earth, acrylic particles, and styrene particles. Polyethylene particles, polypropylene particles, and the like. In the surface treatment agent, the pigment particles may be separately formulated or two or more of the pigment particles may be mixed and formulated.

The particle diameter of the pigment particles is preferably 20 μm or less, and more preferably 15 μm or less, in order to suppress the powder particles from falling off from the coating layer of the surface treatment agent. Further, in order not to reduce the amount of the polymer binder in the surface treatment layer, the content of the pigment particles in the surface treatment layer is more preferably from 0 to 60% by weight, still more preferably from 0 to 45% by weight. Thereby, the binder resin is sufficient and the printing ink becomes less likely to be peeled off.

(surface oxidation treatment)

The surface treatment of the thermoplastic resin film is carried out by the application of the above surface treatment agent, and the surface treatment agent is preferably an aqueous solution or an aqueous dispersion from the viewpoints of safety, cost, and the like. However, when an aqueous solution or an aqueous dispersion is applied to the surface of the thermoplastic resin film, it is easily repelled. Therefore, it is preferred to subject the surface of the thermoplastic resin film to surface oxidation treatment in advance. By performing the surface oxidation treatment, the adhesion between the surface of the thermoplastic resin film and the surface treatment layer formed by the application of the surface treatment agent can be improved.

Examples of the surface oxidation treatment include corona discharge treatment, flame treatment, plasma treatment, glow discharge treatment, and ozone treatment. Among them, corona discharge treatment and plasma treatment are preferably used.

Regarding the amount of oxidation treatment, in the case of corona discharge treatment, in order to carry out stable and effective oxidation treatment, it is preferably 10 W ‧ min/m ² (600 J/m ² ) or more, more preferably 20 W ‧ min/m ² ( 1,200J/m ² ) or more. On the other hand, if the oxidation treatment is excessive, the adhesion to the surface treatment layer formed in the subsequent step is rather decreased. Therefore, the oxidation treatment amount is preferably 200 W‧ min/m ² (12,000 J/m ² ) or less, more preferably 180 W ‧ min / m ² (10,800 J / m ² ) or less.

(coating)

A coating liquid containing the above components can be prepared, and if necessary, the coating liquid is applied onto the surface of the thermoplastic resin film subjected to surface oxidation treatment, and further dried and solidified to provide a surface treatment layer. Previously known methods or devices can be utilized for application.

Examples of the solvent for adjusting the coating liquid include water, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, ethyl acetate, toluene, xylene, and the like. These solvents may be used singly or in combination of two or more. Among them, the management of the coating step is facilitated by using water. Further, the antistatic agent and the polymer binder may be insoluble in water depending on the composition thereof, and alcohols and ketones which are compatible with water may be used as a solubilizing agent.

The solid content concentration of the total amount of the above components in the coating liquid is preferably 0.1% by mass or more, and more preferably 0.2% by mass or more. Further, the solid content concentration of the total amount of the above components in the coating liquid is preferably 20% by mass or less, and more preferably 10% by mass or less.

As a coating method of a coating liquid, a pattern coater, a roll coater, a gravure coater, a spray coater, a knife coater, a reverse coater, an air knife coater, etc. are used. In addition to the method of applying a coating device such as a size press coater, a dipping method can also be used.

When a thermoplastic resin film is used as the printing paper, one of the causes of the decrease in the adhesion between the film and the ink, the printing ink, the thermal coating liquid, and the like is that the surface treatment layer is too thick. If the surface treatment layer is too thick, it may be damaged inside it. Therefore, the coating amount of the coating liquid on the thermoplastic resin film is preferably 5 g/m ² or less, more preferably 2 g/m ² or less, in terms of the dry solid content per unit area (m ² ), and further It is preferably 1 g/m ² or less. Further, in order to form a surface-treated layer homogeneously on the surface of the thermoplastic resin film to obtain a sufficient antistatic effect, or to improve the adhesion with ink, printing ink, thermal coating liquid or the like, the coating amount of the coating material is preferably It is 0.005 g/m ² or more, more preferably 0.01 g/m ² or more, still more preferably 0.02 g/m ² or more.

After applying a surface treatment agent to the surface of the thermoplastic resin film, the coating film is dried to obtain a surface treatment layer. The drying of the coating film may be natural drying, or may be heat drying using an oven or the like.

[Formation of Thermoplastic Resin Film] (film forming)

As a method of forming the thermoplastic resin film, a usual resin film forming method, a lamination method, and an extension method can be used.

Specific examples of the molding method include a method in which a molten resin (resin composition) is extrusion-molded in a sheet form using a single layer or a plurality of T-die or I-die connected to a screw-type extruder.

[Multilayered]

The thermoplastic resin film has one or more layers including a light stabilizer (1) and a light stabilizer (2), and may have a two-layer structure or a multilayer structure of three or more layers, and the number of extension axes of the multilayer structure may be Single axis / single axis, single axis / two axis, two axis / single axis, single axis / single axis / two axis, single axis / two axis / single axis, two axis / single axis / single axis, single axis / two Axis / two axes, two axes / two axes / single axis, two axes / two axes / two axes. By multilayering the thermoplastic resin film, various functions such as printability, additional recording property, abrasion resistance, and secondary processing suitability can be improved.

Specific examples of the lamination method in the case where the thermoplastic resin film has a multilayer structure include laminating a molten resin in a mold using a multilayer T-die or an I-die, and extruding it in a sheet form, using a metal roll or a rubber. A co-extrusion method of obtaining a multilayer sheet by cooling a roll, a metal strip, or the like; a lamination method of a multilayer sheet by laminating a molten resin on another sheet using a plurality of T-die or I-die. Among these, it is preferred that the thermoplastic resin composition constituting the thermoplastic resin film is supplied to an extruder and melted, and a T die connected to the extruder is used. Casting method in which a sheet is extruded and pressed onto a cooling roll for cooling.

(extend)

The thermoplastic resin film is preferably formed by stretching the above-mentioned sheet (resin composition) in at least a uniaxial direction. A porous film is obtained by stretching, and a film having a uniform thickness is easily obtained, and the thermoplastic resin film is suitable as a printing paper or a reflector.

Specific examples of the stretching method include a method of uniaxially stretching the sheet in a machine direction by a circumferential speed difference of a roll group, and a uniaxial stretching method in a lateral direction (width direction) by a tenter oven. And, in turn, a sequential two-axis extension method using a longitudinal extension of the circumferential speed difference of the roll group and a lateral extension using a tenter oven; a simultaneous two-axis extension method using a combination of a tenter oven and a linear motor; using a tenter oven A simultaneous biaxial stretching method of a combination of the pantilizers; or a simultaneous biaxial stretching method using an inflation molding method (tubular method) using an O-die and a pressure. Among these, it is particularly preferable to use a sequential two-axis stretching method in which the stretching ratio is easily changed on the extension axis, and the longitudinal extension of the circumferential speed difference by the roll group is combined with the lateral extension by the tenter oven.

The stretching ratio at the time of the stretching is preferably 1.3 times or more, more preferably 2 times or more, further preferably 4 times or more, and particularly preferably 6 times or more. Similarly, the stretching ratio at the time of the stretching is preferably 15 times or less, more preferably 14 times or less, still more preferably 12 times or less, and still more preferably 10 times or less.

Moreover, the sheet (resin composition) may be extended in the biaxial direction to obtain a thermoplastic resin film. In the case of the biaxial stretching, it is preferable that the product of the longitudinal stretching ratio and the lateral stretching ratio, that is, the area stretching ratio is 4 times or more, preferably 9 times or more, more preferably 12 times or more, and further preferably 20 times or more. , especially good for 30 times or more. Similarly, the area stretching ratio is preferably 80 times or less, more preferably 70 times or less, further preferably 60 times or less, and particularly preferably 50 times or less.

When the stretching ratio is within the above range, it is easy to obtain fine pores, and it is easy to adjust opacity or achieve high reflectance by obtaining a desired porosity.

The extension temperature at the time of the extension is a temperature lower than the melting point of the thermoplastic resin to be used by 2 ° C or more and 60 ° C or less, and is a temperature higher than the glass transition point of the thermoplastic resin to be used by 2 ° C or more and 60 ° C or less. For example, when the thermoplastic resin is a propylene homopolymer (melting point: 155 to 167 ° C), it is preferably 95 ° C or more and 165 ° C or less. By performing film formation at the above extension temperature, it is easy to form desired pores inside the film.

Further, the stretching speed at the time of the stretching is preferably 20 m/min or more and 350 m/min or less.

Further, by heat treatment by stretching the obtained thermoplastic resin film, the heat shrinkage rate in the extending direction is lowered, and the curl during storage of the product or the surface waviness due to shrinkage during heat and fusion sealing is reduced. The heat treatment method is usually carried out using a roll and a hot oven, or may be combined. From the viewpoint of obtaining a higher treatment effect, the heat treatment is preferably carried out while maintaining the stretched film under tension.

<Properties of thermoplastic resin film> [thickness]

The thickness of the thermoplastic resin film was measured in accordance with JIS P8118:1998 "Testing methods for paper and paperboard - thickness and density" using a constant pressure thickness measuring device. The thickness of the thermoplastic resin film is preferably 20 μm or more, more preferably 40 μm or more, and still more preferably 60 μm or more from the viewpoint of obtaining sufficient rigidity in the use of the outdoor notice as a large poster or the like. On the other hand, the thickness of the thermoplastic resin film is preferably 250 μm or less, and more preferably 200 μm or less from the viewpoint of avoiding excessive weight of the printing paper or the label.

[density]

The density of the thermoplastic resin film is a value obtained by the above method according to JIS P8118:1998 "Test method for paper and paperboard - thickness and density", and a method for measuring paper and paperboard - basis weight according to JIS P8124:2011. The value of the basis weight obtained by punching a sample into a size of 10 cm × 10 cm and measuring the mass was calculated by the following calculation formula.

ρ=Wf/(Tf×1000)

In the above formula, ρ, Wf and Tf respectively mean the following values.

ρ: density of thermoplastic resin film (g/cm ³ ), Wf: basis weight of thermoplastic resin film (g/m ² ), Tf: thickness of thermoplastic resin film (mm)

The thermoplastic resin film preferably has a density of 0.5 g/cm ³ or more, more preferably 0.6 g/cm ³ or more, from the viewpoint of maintaining the surface strength of the printing paper or the label. On the other hand, the density of the thermoplastic resin film is preferably 1.3 g/cm ³ or less, and more preferably 1.0 g/cm ³ or less from the viewpoint of avoiding excessive use of the printing paper or the label.

[void rate]

When the thermoplastic resin film contains one or more layers of a porous thermoplastic resin layer having a plurality of pores formed therein by the above-described stretching or the like, the amount of pores per unit volume can be expressed as pores. rate. The porosity of the porous thermoplastic resin layer was calculated by the following calculation formula 3 using the density ρ obtained by the above measurement and the true density ρ ₀ measured by the density of the resin composition used for the layer formation.

ρ ₀ : true density of porous thermoplastic resin layer

ρ: density of porous thermoplastic resin layer

Here, the true density of the porous thermoplastic resin layer is equal to its density as long as the resin composition before stretching does not contain a large amount of air. When the true density is obtained from the porous thermoplastic resin layer, the porous thermoplastic resin layer is completely shrunk at a temperature higher than the elongation temperature by 5 ° C or higher and 5 ° C or lower from the melting point to obtain a true density measurement. Sample. When the true density of the resin composition is determined, the particles of the resin composition are directly used as Sample for true density measurement. The true density of the sample was measured by the A method (aqueous substitution method) of JIS K7112:1999 "Method for Measuring Density and Specific Gravity of Plastic-Non-Foamed Plastics".

The porosity of the porous thermoplastic resin layer is preferably 5% by volume or more, more preferably 10% by volume or more, and still more preferably 15 from the viewpoint of achieving high opacity and light reflectance of the thermoplastic resin film. More than 5% by volume, particularly preferably 20% by volume or more.

On the other hand, the porosity of the porous thermoplastic resin layer is preferably 70% by volume or less, more preferably 65% by volume or less, and still more preferably 63% by volume or less from the viewpoint of maintaining the surface strength of the thermoplastic resin film. .

Further, the thermoplastic resin film may have a porous thermoplastic resin layer as a whole and have a porosity in the above range, and the thermoplastic resin film may have one or more porous thermoplastic resin layers and the layer has a porosity in the above range.

[Opacity]

Regarding the opacity of the thermoplastic resin film, a black and white standard plate is attached to the back surface of the measurement sample in accordance with JIS P8149:2000 "Paper and Paperboard - Opacity Test Method (Paper Backing) - Diffusion Illumination Method" The percentage indicates the ratio of the reflectance of light (black plate/white plate) to indicate the opacity of the thermoplastic resin film.

The opacity of the thermoplastic resin film is preferably from 5 to 100% when used as a printing paper and for use in a poster or the like, and is preferably from 10 to 40% when used for a lighting kanban or the like. Further, when used as a printing paper and used for a white film, it is preferably 60 to 100%, more preferably 70 to 100%. Further, when used for a reflector, it is preferably 95 to 100%, more preferably 98 to 100%.

[surface resistivity]

Regarding the surface resistivity of the thermoplastic resin film, by performing the above surface treatment, it can be suppressed to be lower than that of the untreated one, and it is difficult to carry static electricity.

The surface resistivity of the thermoplastic resin film is 23 ° C and 50% relative humidity, and the surface resistivity is 1 × 10 ⁷ Ω or more, in accordance with JIS-K6911:2006 "Test of thermosetting plastics. The method was carried out using an electrode of a double loop method. When the surface resistivity is less than 1 × 10 ⁷ Ω, the resistance is determined by a four-probe method in accordance with JIS-K7194 "Resistance test method using a four-probe method for conductive plastics". (R) is multiplied by the correction factor F, and the obtained value is taken as the surface resistivity. The surface resistivity of the thermoplastic resin film is preferably 1 × 10 ¹² Ω or less, more preferably 5 × 10 ¹¹ Ω or less, and still more preferably 2 × 10 ¹¹ Ω from the viewpoint of efficient printing or post-treatment. the following. Further, from the viewpoint of reducing the cost due to the use of the antistatic agent and making the surface of the thermoplastic resin film less likely to be colored, the surface resistivity of the thermoplastic resin film is preferably 7 × 10 ⁹ Ω or more, more preferably 8 × 10 ^{9 .} Ω or more, and further preferably 9 × 10 ⁹ or more.

[surface water contact angle]

The water contact angle of the surface of the thermoplastic resin film can be adjusted from the untreated person by performing the above surface treatment, and it becomes easier to print.

The water contact angle of the surface-treated surface of the thermoplastic resin film was measured in accordance with the static dropping method of JIS R3257:1999 "Test method for wettability of substrate glass surface". When the thermoplastic resin film is lithographically printed, the water contact angle is preferably 75 or more, more preferably 80 or more, and still more preferably 85 or more from the viewpoint of printing failure due to emulsification. On the other hand, the water contact angle is preferably 120 or less, more preferably 110 or less, and further preferably 100, from the viewpoints of transfer of printing ink, performance of antistatic property, easiness of post-treatment property, and the like. the following.

[light reflectance]

The thermoplastic resin film contains a porous thermoplastic resin layer in which a large number of pores are formed in the film along with the above extension, whereby the light reflectance can be improved and it is useful as a reflector. The light reflectance of the thermoplastic resin film is as follows: According to the method described in JIS-Z8722:2009 "Method for measuring color - reflection and transmission of object color", a spectrophotometer equipped with an integrating sphere having a diameter of 150 mm is used. , in the form of a relative value when the light reflectance of the alumina plate as a standard plate is set to 100%, measured in units of 5 nm The light reflectance at a wavelength of 430 to 550 nm of the measuring portion on the side of the light reflecting surface of the test piece, and the obtained measured value is averaged.

In the present invention, first, the light reflectance of the test piece is obtained, and then the light resistance test described in the following examples is carried out, and then the light reflectance of the test piece is obtained again, and the light reflectance before and after the light resistance test is calculated. The amount of decrease △. When a thermoplastic resin film is used as the reflector, the amount of decrease Δ of the light reflectance before and after the test is preferably 2% or less from the viewpoint that the light reflectance hardly decreases and the excellent light reflection performance is maintained. More preferably, it is 1.5% or less, further preferably 1.2% or less, and particularly preferably 0.7 or less.

<Use of thermoplastic resin film> [printing paper]

The thermoplastic resin film of the present invention can be directly printed as printing paper by a method such as lithography, flexographic printing, gravure printing, letterpress printing, screen printing, or electrophotographic recording. From the viewpoint of the fineness of printing, it is preferably a gravure printing, an inkjet recording method, or an electrophotographic recording method, and it is preferably a relief printing or a flexographic printing from the viewpoint of a small batch size.

The printed matter containing the thermoplastic resin film has water resistance and high resistance to light, and thus is particularly suitable for posters used for outdoor posters or lighting kanbans.

Further, the thermoplastic resin film may be provided as a label by providing a layer of an adhesive on one surface thereof. The label can also be printed on its display surface. Further, the label may further laminate the release sheet on the layer of the adhesive.

Specific examples of the above-mentioned adhesives include known adhesives such as a rubber-based adhesive, an acrylic adhesive, and a polyoxygen-based adhesive. Further, the adhesive may be used singly or in combination of two or more.

When the wetting of water on the surface of the printing paper by one of the printing methods is too good due to the surface treatment layer, there is a case where the printing ink is easily emulsified and the ink is difficult to transfer. On the other hand, when the moisture of the surface of the printing paper is too wet, The case where the ink adheres to the non-printing portion of the lithographic printing material to cause scumming. Therefore, when a thermoplastic resin film is used as the printing paper for lithography, it is important that the water contact angle of the surface subjected to the surface treatment is controlled within the above-mentioned appropriate range.

An oil-based ink and an ultraviolet-curable ink can be used for the ink used in the printing. Among these, it is preferable to use an ultraviolet curable ink from the viewpoint of quick-drying property and abrasion resistance of a printed matter. In the case of performing printing using an ultraviolet curable ink, the ink is dried and cured by ultraviolet irradiation. The ultraviolet irradiation method is not particularly limited as long as it is a method of curing the ultraviolet curable ink, and examples thereof include a metal halide lamp (light wavelength of 200 to 400 nm), a low pressure mercury lamp (180 to 250 nm), and a high pressure mercury lamp (250~). 365nm), black light (350~360nm), UV-LED (Ultraviolet-Light Emitting Diode) lamp (355~375nm), to be 300~3000mJ/cm ² , preferably 400~1000mJ A method of irradiating ultraviolet rays irradiated from the light source or the like in a manner of an irradiation amount of /cm ² .

[reflector]

The reflector of the present invention can efficiently reflect light from the source in the normal direction due to its higher light reflectivity. Moreover, the resistance to light emitted from the light source is high, and the long-term decrease in light reflectance is small. Therefore, it is extremely useful as a built-in light source reflector used in a backlight for a liquid crystal display device such as a liquid crystal TV (TV) or a liquid crystal monitor, and a backlight for a lighting fixture. Further, it is also useful as a reflector that is provided on the back surface of a fluorescent lamp or an LED illumination device and that can reflect light from a light source to the irradiation surface side. When the thermoplastic resin film is used as the reflector, the light reflectance calculated by the above method is preferably 96% or more, more preferably 97% or more, still more preferably 97.5% or more. When the light reflectance of the thermoplastic resin film is 96% or more, it has excellent reflection performance as a reflector, and a liquid crystal display device or a lighting bezel incorporating such a reflector can achieve sufficient brightness of the screen.

Further, in the case where a thermoplastic resin film is used as the reflector, it is preferably utilized. After the continuous weathering test for 500 hours, no crack due to deterioration of the resin was observed on the surface to be irradiated. Further, the amount of decrease in the light reflectance after the light resistance test is preferably 2% or less, more preferably 1.5% or less, further preferably 1.2% or less, and particularly preferably 1% or less. When the amount of decrease is 2% or less, no crack is observed as a solid after the light resistance test, and the decrease in the light reflectance under the actual use environment of the reflector can be sufficiently suppressed.

[Examples]

The present invention will be further specifically described below by way of examples, comparative examples and test examples. The materials, usage amounts, ratios, operations, and the like shown below may be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the invention is not limited to the specific examples shown below.

[test] (thickness)

The thickness of the thermoplastic resin film obtained in the following Examples and Comparative Examples was measured by using a thickness gauge (manufactured by HIGH BRIDGE Co., Ltd.) in accordance with the method described in JIS P8118:1998. The results are shown in Table 4.

(base weigh)

The basis weight of the thermoplastic resin film obtained in each of the following Examples and Comparative Examples was punched into a square of 10 cm × 10 cm in accordance with the method described in JIS P8124:2011, and the mass thereof was measured. The results are shown in Table 4.

(density)

The density of the thermoplastic resin film obtained in each of the following examples and comparative examples was determined by dividing the thickness measured by the above method by the basis weight measured by the above method in accordance with the method described in JIS P8118:1998.

(empty porosity)

The porosity of the thermoplastic resin film obtained in each of the following examples and comparative examples is a measured value of the true density ρ ₀ of the resin composition obtained by the method described in JIS K7112:1999, and the thermoplasticity determined by the above method. The calculated value of the density ρ of the resin film was calculated according to the above formula.

[Light resistance evaluation]

The thermoplastic resin film obtained in each of the following Examples and Comparative Examples was cut into a square of 5 cm × 5 cm to prepare a test piece. The test piece was placed at a position of 5 cm from an ultraviolet lamp having a dominant wavelength of 310 nm under an environmental condition of 63 ° C, and the surface of the test piece was continuously irradiated with ultraviolet rays for 500 hours with a surface irradiation intensity of 0.76 W/m ² to promote the light resistance test. . Then, the surface to be irradiated of the test piece after the light resistance test was visually observed using an optical microscope, and the presence or absence of deterioration of the resin was evaluated according to the following criteria.

○: no crack was observed

×: Crack can be confirmed

Moreover, the light reflectance of the surface to be irradiated of the test piece before and after the light resistance test was measured by the above method, and the difference between the two was taken as the rate of decrease Δ.

[Oxidation Gas Evaluation]

The thermoplastic resin film obtained in the following Examples and Comparative Examples was cut into a square of 10 cm × 10 cm, and a joint was inscribed at the center portion to prepare a test piece. The test piece was placed in a desiccator of about 15 L in a non-overlapping manner, and then an aqueous solution of 30 mg of sodium nitrite and 11 g of phosphoric acid was mixed in a desiccator so that the concentration of the nitrogen oxide gas in the drier was about 650 ppm. Immediately thereafter, the lid of the dryer was closed and sealed, and left in the dark room for 3 days. The test piece after standing was visually observed, and the discoloration property by an oxidizing gas was evaluated on the following basis.

◎: Discoloration could not be confirmed.

○: Discoloration is permitted at the seam portion or end portion.

△: Discoloration was clearly visible at the edge of the test piece.

×: Discoloration was observed on the entire test piece.

[Printing test]

The thermoplastic resin film obtained in each of the following Examples and Comparative Examples was cut into a square of 10 cm × 10 cm to prepare a test piece. After one side of the test piece was subjected to corona discharge treatment at a treatment amount of 60 W ‧ min/m ² , a printing test machine (manufactured by Mingsho Co., Ltd., trade name: RI-III type printability test machine) was used. Printing ink (manufactured by T&K TOKA Co., Ltd., trade name: BEST CURE-161 ink) was uniformly printed on the corona discharge treated surface so as to have a thickness of 1.5 g/m ² . Thereafter, the printed surface of the test piece was subjected to UV irradiation at a UV irradiation intensity of 0.04 W/cm ² in a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd., power: 80 W/cm) to dry and solidify the printing ink. Stored in an environment with a temperature of 23 ° C and a relative humidity of 50% for 1 day.

Then, a transparent tape (manufactured by Nichiban Co., Ltd., trade name: CT-18) was attached to the printing surface, and an internal bond tester (Kumai Rico Industry Co., Ltd.) was used in accordance with JAPAN TAPPI No. 18-2 (internal bond strength test method). The company's manufacturing, trade name) determines the peel strength of the ink. The average value of the two measurement results was used as the adhesion strength, and the evaluation was performed according to the following criteria.

○: Qualified, the adhesion strength is 1.4kg‧cm or more

×: Unqualified Bonding strength is less than 1.4kg‧cm

[Material of thermoplastic resin film]

In each of the examples and comparative examples, those shown in Table 3 were used as the material of the thermoplastic resin film.

(Example 1)

Using the two-axis kneading machine set to 210 ° C, the PP1 (54.3 quality) listed in Table 3 will be included. a mixture of CA1 (40 parts by mass), TI (5 parts by mass), LS1 (0.2 parts by mass), LS5 (0.2 parts by mass), AO1 (0.1 parts by mass), and AO7 (0.2 parts by mass) after melt-kneading The pellet was extruded in a strand shape using an extruder set at 230 ° C, and after cooling, it was cut by a strand cutter to prepare pellets of the resin composition.

Next, the above resin composition was melt-kneaded at 250 ° C using an extruder, extruded in a sheet form from a T mold, and cooled to about 60 ° C by a cooling roll, whereby a resin sheet was obtained. After reheating the resin sheet to 145 ° C, the longitudinal stretching sheet was obtained by stretching at a peripheral speed difference of a plurality of roll groups in the longitudinal direction at 4.8 times.

Then, the longitudinally stretched sheet was further heated to 160 ° C, and then stretched by 9 times in the transverse direction by a tenter, then annealed at 165 ° C to be cooled to 60 ° C, and the edges were cut to obtain a thickness of 100 μm. A thermoplastic resin film having a porosity of 54%.

(Examples 2 to 11, 15, 16 and Comparative Examples 1 and 2)

In the same manner as in Example 1, except that the composition of the resin composition, the stretching ratio in the longitudinal direction, and the stretching ratio in the transverse direction were changed as described in Table 4, the thickness and the space described in Table 4 were obtained in the same manner as in Example 1. A thermoplastic resin film having a porosity.

(Embodiment 12)

The HDPE (29.6 parts by mass), CA-3 (69.8 parts by mass), LS1 (0.2 parts by mass), LS5 (0.2 parts by mass), AO1 described in Table 3 were contained in a two-axis kneading machine set at 180 °C. The mixture of (0.1 part by mass) and AO7 (0.1 part by mass) was melt-kneaded, and then supplied to a T die set at 190 ° C, extruded in a sheet form, and the resulting sheet was cooled to about 40 ° C by a cooling roll. An unstretched sheet of 285 μm was obtained.

Then, after the unstretched sheet was reheated to 110 ° C, the circumferential speed difference of the roll group was doubled in the longitudinal direction, the uniaxially stretched sheet was cooled to 60 ° C, and then heated using a tenter oven to After 120 ° C, the tenter was stretched twice in the transverse direction, and then annealed by a heat setting region adjusted to 130 ° C, cooled to about 60 ° C by a cooling roll, and the edge portion was cut to obtain a thickness of 122 μm. A thermoplastic resin film having a porosity of 58%.

(Example 13)

In Example 12, AO6 (0.1 parts by mass) was used instead of AO1 (0.1 parts by mass), and AO9 (0.1 parts by mass) was used instead of AO7 (0.1 parts by mass), except that the same procedure as in Example 12 was obtained. A thermoplastic resin film having a thickness of 125 μm and a porosity of 58%.

(Example 17)

The HDPE (5 parts by mass), PP1 (84.8 parts by mass), AC1 (15 parts by mass), AO1 (0.1 parts by mass), and AO7 (0.1) described in Table 3 were used in a two-axis kneading machine set at 210 °C. After the mixture of the mass parts was melt-kneaded, it was extruded in a strand shape by an extruder set at 230 ° C, and after cooling, it was cut by a strand cutter to prepare pellets of the resin composition a which became a porous thermoplastic resin layer.

On the other hand, a mixture containing PP2 (98.8 parts by mass), LS1 (0.6 parts by mass), and LS5 (0.6 parts by mass) described in Table 3 was melted and kneaded by a two-axis kneading machine set at 210 ° C, and then used. The extruder set to 230 ° C was extruded in a strand shape, and after cooling, it was cut by a strand cutter to prepare pellets of the resin composition b which became the surface layer.

Then, the resin composition a and the resin composition b were separately melted and kneaded by three extruders set at 230 ° C, and then supplied to a feed block type multilayer mold set at 250 ° C to become b/a/. The order of b was laminated in a mold and extruded in a sheet form, and the sheet was cooled to 60 ° C by a cooling device to obtain a three-layered unstretched sheet.

Then, the unstretched sheet was heated to 145 ° C, and the circumferential speed difference of the roll group was used to extend 4 times in the longitudinal direction, the uniaxially stretched sheet was cooled to 60 ° C, and then heated to 155 ° C using a tenter oven. Thereafter, the film was stretched 9 times in the transverse direction by a tenter, and further annealed by a heat setting zone adjusted to 160 ° C, cooled to about 60 ° C by a cooling roll, and the side portion was cut to obtain a thickness of 130 μm. A thermoplastic resin film having a porosity of 65%.

The appearance of the thermoplastic resin film of Examples 1 to 17 and Comparative Examples 1 and 2 was evaluated for the appearance of the weather resistance test and the appearance of the oxidizing gas evaluation. Further, with respect to Examples 1 to 11, Examples 14 to 16, and Comparative Examples 1 and 2, the light reflectance decrease amount Δ before and after the weather resistance test was evaluated. The results are shown in Table 5.

The thermoplastic resin film of Example 1 was cut into a width direction of 210 mm and a machine direction of 297 mm, and a printing test was carried out as a test piece. As a result, the adhesion strength was 2.4 kg‧cm, and there was no particular problem in ink adhesion.

As shown in Table 5, the thermoplastic resin film of Examples 1 to 17 containing the light stabilizer (1) having a molecular weight of 600 or less and the light stabilizer (2) having a molecular weight of 650 or more was not confirmed to have cracks after the light resistance test. , showing good weatherability.

In the thermoplastic resin film of Examples 1 to 10, the light reflectance at a wavelength of 430 to 550 nm is 82% or more, preferably 99% or more, and further, the amount of decrease in light reflectance is Δ2 or less, and the light resistance test is performed. Excellent light reflectance is also maintained afterwards, thus exhibiting a preferred property as a reflector.

On the other hand, it was found that the thermoplastic resin film of Comparative Examples 1 and 2 containing one of the light stabilizer (1) and the light stabilizer (2) and containing the other one was confirmed to have cracks on the surface after the light resistance test. The amount of decrease in reflectance was 3% or more, which was inferior to the thermoplastic resin film of each example.

Further, in Example 16, as compared with Example 15, the light reflectance before the weather resistance test was improved, and it was found that the antioxidant represented by the formula (1) or (2) has thermal deterioration during the resin molding process. The function. However, the oxidizing gas of Example 16 was evaluated as Δ, and the oxidizing gas of Example 15 was evaluated as ◎, and it was found that the antioxidant represented by Formula (1) or Formula (2) was easily oxidized by itself. Coloring.

In the examples of the single-layer structure, the oxidizing gases of Examples 1 to 10, 12, and 14 were evaluated as ○ ◎ ◎, and it was found that a phosphorus-based antioxidant was used in combination as a secondary antioxidant, or a combination of phosphoric acid was used in the molecule. The antioxidant of the ester structure serves as a primary antioxidant, and the discoloration caused by the oxidizing gas can be satisfactorily suppressed.

Further, in the case of the laminate having the porous layer, it is effective in that the layer in which the surface is exposed contains the light stabilizer (1) and the light stabilizer (2), and the porous layer contains the formula. (1) or an antioxidant represented by the formula (2).

Moreover, the results of the printing test of the thermoplastic resin film of Example 1 were good, and it was considered that the thermoplastic resin films of Examples 2 to 17 also had good printing suitability.

[Industrial availability]

The thermoplastic resin film of the present invention is less prone to deterioration such as cracks even when exposed to light for a long period of time, and can suppress discoloration caused by an oxidizing gas, and thus can be preferably used for long-term exposure to light. Printing paper, etc. Again, there is almost no Since the light reflectance due to ultraviolet rays is lowered and the excellent light reflectance can be maintained for a long period of time, it can be preferably used as a reflector for a liquid crystal display device such as a liquid crystal display, a lighting fixture, an illumination device, or the like.

Claims (19)

A thermoplastic resin film comprising one or more film layers obtained by molding a resin composition, and the resin composition forming the film layer contains a thermoplastic resin and a light stabilizer having a molecular weight of 600 or less (1) And a light stabilizer (2) having a molecular weight of 650 or more. The thermoplastic resin film of claim 1, wherein the content of the light stabilizer (1) relative to the total solid content of the resin composition is 0.01 to 1% by mass, and the light stabilizer (2) is relative to the resin The content of the total solid content of the composition is 0.01 to 1% by mass. The thermoplastic resin film of claim 1, wherein the light stabilizer (2) is a hindered amine light stabilizer. The thermoplastic resin film according to claim 1, wherein the resin composition further comprises at least one of a phenolic antioxidant represented by the following formula (1) and an antioxidant represented by the following formula (2). (In the formula (1), any one of R ¹ and R ³ is a hydroxyl group, the other represents a hydrogen atom; R ² represents an alkyl group having a carbon number of 3 or more; and R ⁴ represents a branched alkyl group having 1 to 6 carbon atoms; n; n represents an integer from 1 to 3; when n is 1, L is a substituent; when n is 2 or 3, L is a linking group, and a plurality of R ¹ to R ⁴ are the same or different from each other); (In the formula (2), R ⁵ and R ⁶ each independently represent a saturated alkyl group having 1 to 24 carbon atoms). The thermoplastic resin film of claim 4, wherein the resin composition comprises a phenolic antioxidant represented by the formula (1). The thermoplastic resin film according to claim 4, wherein the content of the phenolic antioxidant relative to the total amount of the solid content of the resin composition is 0.01 to 2% by mass. The thermoplastic resin film according to any one of claims 1 to 6, wherein the above resin composition further comprises a filler and is extended at least in a uniaxial direction. The thermoplastic resin film according to claim 7, wherein the filler is at least one of an inorganic filler having a volume average particle diameter of 0.05 to 10 μm and an organic filler having an average dispersed particle diameter of 0.05 to 10 μm. The thermoplastic resin film according to claim 7, wherein the resin composition contains the filler in an amount of 5 to 75% by mass based on the total amount of the solid component. The thermoplastic resin film of claim 7, wherein the extension is an extension in a uniaxial direction, and the stretching ratio is 1.3 to 15 times. The thermoplastic resin film according to claim 7, wherein the extension is an extension in the biaxial direction, and the stretching ratio is 4 to 80 times in terms of area stretching ratio. The thermoplastic resin film of claim 7, which contains one or more porous thermoplastic resin layers, and the porosity of the porous thermoplastic resin layer obtained by the following formula (3) is 5 to 70% by volume. ρ ₀ : true density of the porous thermoplastic resin layer ρ: density of the porous thermoplastic resin layer. The thermoplastic resin film according to any one of claims 1 to 6, wherein the thermoplastic resin contained in the resin composition contains at least one of a polyolefin resin and a polyester resin. A printing paper using the thermoplastic resin film of any one of claims 1 to 13. A label using the thermoplastic resin film of any one of claims 1 to 13. A reflector using the thermoplastic resin film of any one of claims 1 to 13. A liquid crystal display device using a reflector as claimed in claim 16. A lighting kanban that uses a reflector as claimed in claim 16. A lighting device that uses a reflector as claimed in claim 16.