JP2008208197A - Colored acrylic resin film for surface skin material of retroreflective sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a colored acrylic resin film for a surface skin material of a retroreflective sheet equipped with weather resistance and visibility required in the case of being used as the retroreflective sheet and also satisfying transparency and hue. <P>SOLUTION: This colored acrylic resin film used as the surface skin material of the retroreflective sheet and containing the acrylic resin, an anthraquinone-based red-colored pigment and anthraquinone-based yellow-colored dyestuff is provided by blending 0.5 to 1 pt.wt. anthraquinone-based red colored pigment based on 100 pts.wt. acrylic resin, and having (1/5) to (10/1) mass ratio of the anthraquinone-based red-colored pigment to the anthraquinone-based yellow-colored dyestuff (the anthraquinone-based red-colored pigment)/(the anthraquinone-based yellow dyestuff) and ≥17% total light transmittance measured by a method prescribed by the JIS K7361-1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is provided for the purpose of protecting retroreflective sheets used for signboards, road signs, etc., and for imparting design properties to the base material of retroreflective sheets, and for transparent and colored retroreflective sheeting materials. Relates to the acrylic resin film.

  Retroreflective sheets that reflect incident light toward the direction of the light source are well known in the art, and are used in various fields by taking advantage of their retroreflective properties and excellent visibility at night. For example, a road sign, a construction sign, etc. using a retroreflective sheet reflects light from a light source such as a headlight of a traveling vehicle at night or the like toward the light source direction, that is, the direction of the traveling vehicle. It provides excellent visibility to the driver of the vehicle who is the viewer of the vehicle and enables clear information transmission. Retroreflective sheets used as such road signs, construction signs, etc. are colored for good visibility, and characters and patterns are directly screen printed on the colored retroreflective sheets. It is formed by.

There are white, yellow, red, yellow-red, green, and blue as the types of colors of the colored retroreflective sheeting. For each color, the range of chromaticity coordinates, the lower limit of the luminance rate (β), the YI value, etc. are JIS. Standards, ASTM standards, DIN standards, etc.
As a method of obtaining the colored retroreflective sheet as described above, (i) a method of coloring the surface layer of the retroreflective sheet by printing; (ii) kneading a colorant in any of the steps until the film is manufactured. A method of laminating the obtained colored film as a protective layer on the base material of the retroreflective sheet is conceivable. Among these methods, the method (ii) is preferable in consideration of the reflection performance and the manufacturing cost of the retroreflective sheet.

As the colored acrylic resin film for the retroreflective sheet skin used in the method (ii), Patent Document 1 discloses a colored acrylic resin film having chromaticity coordinates (x, y) in an XYZ color system in a specific range. Is disclosed.
JP 2005-154720 A

  However, this colored acrylic resin film has a problem that the weather resistance deteriorates when trying to improve visibility while maintaining the chromaticity coordinates (x, y) in the XYZ color system in a specific range. In addition, when the type of the colorant is changed in order to improve weather resistance, there is a problem that visibility is deteriorated.

  Accordingly, an object of the present invention is to provide a colored acrylic resin film for the skin of a retroreflective sheet that has weather resistance and visibility required when used as a retroreflective sheet, and also satisfies transparency and hue. .

The colored acrylic resin film for the skin of the retroreflective sheet of the present invention is a colored acrylic resin film that is used as a skin material for the retroreflective sheet and contains an acrylic resin, an anthraquinone red pigment, and an anthraquinone yellow dye, The anthraquinone red pigment is blended in an amount of 0.5 to 1 part by mass based on 100 parts by mass of the acrylic resin, and the mass ratio of the anthraquinone red pigment to the anthraquinone yellow dye (anthraquinone red pigment / anthra The quinone yellow dye) is 1/5 to 10/1 and has a total light transmittance of 17% or more when measured by a method defined in JIS K7361-1.
The colored acrylic resin film for retroreflective sheeting of the present invention preferably further contains an anthraquinone yellow pigment.
Further, the colored acrylic resin film for the skin of the retroreflective sheet according to the present invention is obtained by superimposing the colored acrylic resin film for the skin of the retroreflective sheet and a gray-colored oily colored paper having a Munsell symbol of N5.5. The Y value measured on the condition of standard light D65 by the illumination and light reception geometric condition a (45 ° illumination, vertical light reception) specified in JIS Z8722 on the colored acrylic resin film side is in the range of 2 to 12. It is preferable.

  According to the colored acrylic resin film for retroreflective sheeting of the present invention, it has weather resistance and visibility required when used as a retroreflective sheet, and also satisfies transparency and hue.

Hereinafter, the present invention will be described in detail.
[Colored acrylic resin film for retroreflective sheeting]
The colored acrylic resin film for the skin of the retroreflective sheeting of the present invention (hereinafter also simply referred to as “colored acrylic resin film”) is a colored acrylic resin film containing an acrylic resin, an anthraquinone red pigment, and an anthraquinone yellow dye. The anthraquinone red pigment is blended in an amount of 0.5 to 1 part by weight, preferably 0.6 to 0.9 parts by weight, based on 100 parts by weight of the acrylic resin constituting the colored acrylic resin film. The mass ratio of the quinone red pigment to the anthraquinone yellow dye (anthraquinone red pigment / anthraquinone yellow dye) is 1/5 to 10/1, preferably 1/4 to 5/1, more preferably 1. / 3 to 3/1.

  When the content of the anthraquinone red pigment and the anthraquinone yellow dye in the colored acrylic resin film satisfies the above range, when the colored acrylic resin film is used as a skin material of the retroreflective sheet, the retroreflective sheet The hue of JIS satisfies the JIS standard, the ASTM standard, etc., and the chromaticity coordinates (x, y) in the XYZ color system of the DIN standard are (0.610, 0.340), (0.638, 0). .312), (0.690, 0.310) and (0.660, 0.340) are satisfied and the visibility is good, and the reflection performance and transparency required for the retroreflective sheet are satisfied. Moreover, when exposed outdoors, discoloration due to color loss due to sunlight or the like is reduced, and weather resistance is also improved.

  Here, “range of (0.610, 0.340), (0.638, 0.312), (0.690, 0.310) and (0.660, 0.340)” is a figure. As shown in FIG. 1, (0.610, 0.340), (0.638, 0.312), (0.690, 0.310), (0.660, 0.340) is connected in order with a straight line, and the region surrounded by connecting the last (0.660, 0.340) and the first (0.610, 0.340) with a straight line means.

  The colored acrylic resin film preferably further contains an anthraquinone yellow pigment. By containing an anthraquinone yellow pigment, the hue and transparency of the resulting colored acrylic resin film become better, and the reflective performance and visibility tend to be better when used as a skin material for a retroreflective sheet It is in. The content of the preferred anthraquinone yellow pigment is 0 to 1 part by mass with respect to 100 parts by mass of the acrylic resin.

Further, the colored acrylic resin film of the present invention has a total light transmittance of 17% or more, preferably 18% or more when measured by the method defined in JIS K7361-1. When the total light transmittance is in such a range, when the colored acrylic resin film is used as the skin material of the retroreflective sheet, the reflection performance and the visibility are improved.
In order to set the total light transmittance of the colored acrylic resin film in such a range, the blending amount of the anthraquinone red pigment and the mass ratio of the anthraquinone red pigment and the anthraquinone yellow dye are in the above ranges. At the same time, the types of acrylic resin, anthraquinone red pigment, and anthraquinone yellow dye to be used may be appropriately selected and combined from those exemplified later.

In addition, the colored acrylic resin film of the present invention is formed by superimposing the colored acrylic resin film on a mouse-colored oil-based colored paper having a Munsell symbol of N5.5, and the colored acrylic resin film side of the illumination and light receiving specified in JIS Z8722. It is preferable that the Y value measured in the condition of the standard light D65 under the geometric condition a (45 ° illumination, vertical light reception) is in the range of 2-12. When the Y value is in such a range, when this colored acrylic resin film is used as the skin material of the retroreflective sheet, the hue of the retroreflective sheet tends to satisfy the JIS standard, the ASTM standard, and the DIN standard. Therefore, when used for road signs, the visibility tends to be good.
In order to set the Y value of the colored acrylic resin film in such a range, the blending amount of the anthraquinone red pigment, the mass ratio of the anthraquinone red pigment and the anthraquinone yellow dye is in the above range, The types of acrylic resin, anthraquinone red pigment, and anthraquinone yellow dye to be used may be appropriately selected from those exemplified later and combined.
In addition, the mouse color of the standard color card 230 of Nippon Color Research Co., Ltd. can be used as the oily colored paper of Munsell symbol N5.5.

<Colorants (pigments and dyes)>
Examples of the anthraquinone red pigment used in the colored acrylic resin film include CI Pigment Red 83, CI Pigment Red 177, and CI Pigment Red 216. Of these, CI Pigment Red 177 is particularly preferred. Examples of products containing CI Pigment Red 177 include “DYMIC MBR 151 Red (content of anthraquinone-based red pigment: 50 mass%)” manufactured by Dainichi Seika Kogyo Co., Ltd., “Ciba Specialty Chemicals Co., Ltd.” It is commercially available as “MICROLEN Red A3B-MC”. The anthraquinone red pigment may be included singly or in combination of two or more.

  Examples of the anthraquinone yellow dye include CI Solvent Yellow 163. Examples of products containing CI Solvent Yellow 163 are “DYMIC MBR D-05 Yellow (content of anthraquinone yellow dye: 91% by mass)” manufactured by Dainichi Seika Kogyo Co., Ltd., Ciba Specialty Chemicals Co., Ltd. It is industrially available as “ORACET Yellow GHS”. The anthraquinone yellow dye may be included singly or in combination of two or more.

  Examples of the anthraquinone yellow pigment include CI Pigment Yellow 24, CI Pigment Yellow 99, CI Pigment Yellow 108, CI Pigment Yellow 123, CI Pigment Yellow 147, and CI Pigment Yellow 199. Of these, CI Pigment Yellow 199 is particularly preferred. A product containing CI Pigment Yellow 199 is industrially available as “DYMIC MBR 421 Yellow (content of anthraquinone-based yellow colorant: 50% by mass)” manufactured by Dainichi Seika Kogyo Co., Ltd. Anthraquinone yellow pigments may be included singly or in combination of two or more.

  In addition, when blending the above pigments and dyes into the acrylic resin, they may be blended in the form of a mixture containing other components as long as they contain these pigments and dyes. For example, when an anthraquinone red pigment is blended with an acrylic resin, a pigment mixture other than red containing an anthraquinone red pigment may be used.

In addition, these pigments and dyes are blended with a binder resin in a high concentration of pigments and dyes, in the form of a so-called colorant masterbatch, mixed with a dispersant and pigments and dyes, and mechanically made into a fine powder. It can also be blended in the form of dry color (dispersible powder colorant).
Examples of the colorant master batch include pellets and soft plates. Moreover, as resin used as a binder, resin same or similar to the acrylic resin used for a colored acrylic resin film is preferable.
Preferable dispersants included in the dry color include calcium stearate and magnesium stearate, and one or more kinds can be used.

  In addition, the colored acrylic resin film has, for the purpose of complementary color, perylene, quinacridone, isoindolinone, isoindoline, perinone, thioindigo, quinophthalone, azo, diketopyrrolopyrrole, dioxane, You may add other coloring agents, such as a phthalocyanine type, in the range in which a weather resistance, transparency, etc. do not fall.

<Acrylic resin>
The colored acrylic resin film of the present invention is a film made of an acrylic resin composition containing an acrylic resin as a main component and added with pigments, dyes and the like as described above. By using an acrylic resin as a main component, excellent properties such as weather resistance can be imparted to the film.

  As the acrylic resin, an acrylic ester or vinyl acetate having at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate and having an alkyl group having 1 to 8 carbon atoms as necessary. , Vinyl chloride, styrene, acrylonitrile methacrylonitrile, and the like as a copolymerization component. Further, polymers described in JP-B-59-36646, JP-B-62-19309, JP-B-63-20459 and JP-A-63-77963 may be used.

Preferred acrylic resins used in the present invention are rubber-containing multistage polymers (I), (III), (IV), and acrylic resins in which a thermoplastic polymer (II) is combined with this as necessary, and more Preferably, the rubber-containing multistage polymer (I) and the thermoplastic polymer (II) are combined, the rubber-containing multistage polymer (III) and the thermoplastic polymer (II) are combined, or the rubber-containing multistage polymer. An acrylic resin comprising a combination of (IV) and a thermoplastic polymer (II), or a rubber-containing multistage polymer (III) alone, or an acrylic resin comprising only a rubber-containing multistage polymer (IV).
When the rubber-containing multistage polymer (I) or (III) or (IV) is combined with the thermoplastic polymer (II), the former is 20 to 90 parts by mass and the latter is 80 to 10 parts by mass. Is preferable (however, (I) + (II) = 100 parts by mass).
Since the retroreflective sheet is mainly used outdoors as a road sign or the like, it is preferable to use a skin material having good weather resistance and impact resistance. For example, as a method of imparting impact resistance, there is a method of containing a rubber component, etc., but in this case, the transparency of the skin material changes due to the change in environmental temperature, and the reflection performance important as a retroreflective sheet is present. It may decrease or the hue of the retroreflective sheet may change. The colored acrylic resin film using the above-mentioned preferable acrylic resin has good weather resistance and impact resistance, and has low temperature dependency of transparency, and therefore can be suitably used as a skin material for a retroreflective sheet.
Hereinafter, the acrylic resin of the preferable form mentioned above is demonstrated concretely.

(Rubber-containing multistage polymer (I))
From the center, the rubber-containing multistage polymer (I) is composed of an elastic polymer (IA), a first intermediate polymer (IB), a second intermediate polymer (IC), and a hard polymer (ID). ) Is a rubber-containing multistage polymer arranged in the order of.

The elastic polymer (IA) includes an alkyl methacrylate (I-A1) having an alkyl group having 4 or less carbon atoms, an alkyl acrylate (IA-2) having an alkyl group having 8 or less carbon atoms, an aromatic vinyl monomer It is a polymer having a glass transition temperature of 10 ° C. or higher, obtained by polymerizing the body (I-A3) and the polyfunctional monomer (I-A4).
The use range of the alkyl methacrylate (I-A1) having an alkyl group having 4 or less carbon atoms is preferably 30 to 99.7% by mass in terms of the transparency of the resulting colored acrylic resin film.
The use range of the alkyl acrylate (I-A2) having an alkyl group having 8 or less carbon atoms is preferably 0.1 to 69.8% by mass.
The use range of the aromatic vinyl monomer (I-A3) is preferably 0.1 to 25% by mass.
The use range of the polyfunctional monomer (I-A4) is preferably 0.1 to 10% by mass.
Moreover, you may use a graft crossing agent (I-A5) in 0-5 mass%.
(However, (I-A1) + (I-A2) + (I-A3) + (I-A4) + (I-A5)) = 100% by mass.)

The glass transition temperature (hereinafter referred to as Tg) of the elastic polymer (IA) is preferably 10 ° C. or higher. When Tg is 10 ° C. or higher, the transparency of the resulting colored acrylic resin film tends to be good.
The amount of the elastic polymer (IA) in the rubber-containing multistage polymer (I) (100% by mass) is from 2 to 35% by mass in terms of impact resistance of the resulting colored acrylic resin film. preferable.

The first intermediate polymer (IB) includes an alkyl acrylate (I-B1) having an alkyl group having 8 or less carbon atoms, an aromatic vinyl monomer (I-B2), a polyfunctional monomer (I -B3) and a polymer having a glass transition temperature of 0 ° C. or less obtained by polymerizing the graft crossing agent (I-B4).
The use range of the alkyl acrylate (I-B1) having an alkyl group having 8 or less carbon atoms is preferably 60 to 99.7% by mass in terms of impact resistance of the resulting colored acrylic resin film.
The use range of the aromatic vinyl monomer (I-B2) is preferably 0.1 to 39.8% by mass.
The use range of the polyfunctional monomer (I-B3) is preferably 0.1 to 10% by mass.
The range of use of the graft crossing agent (I-B4) is preferably 0.1 to 5% by mass.
Moreover, you may use the monomer (I-B5) which has a double bond which can be copolymerized in 0-20 mass%.
(However, (I−B1) + (I−B2) + (I−B3) + (I−B4) + (I−B5)) = 100 mass%.)

The Tg of the first intermediate polymer (IB) is preferably 0 ° C. or lower. When Tg is 0 ° C. or lower, the resulting colored acrylic resin film tends to have good impact resistance.
The amount of the first intermediate polymer (IB) in the rubber-containing multistage polymer (I) (100% by mass) is 5 to 60% by mass in terms of impact resistance of the resulting colored acrylic resin film. It is preferable.

The second intermediate polymer (IC) is composed of an alkyl methacrylate (I-C1) having an alkyl group having 4 or less carbon atoms, an alkyl acrylate (I-C2) having an alkyl group having 8 or less carbon atoms, an aromatic vinyl monomer. It is a polymer obtained by polymerizing a monomer (I-C3) and a graft crossing agent (I-C4).
The use range of the alkyl methacrylate (I-C1) having an alkyl group having 4 or less carbon atoms is preferably 20 to 89.8% by mass in terms of the transparency of the resulting colored acrylic resin film.
The use range of the alkyl acrylate (I-C2) having an alkyl group having 8 or less carbon atoms is preferably 10 to 79.8% by mass.
The use range of the aromatic vinyl monomer (I-C3) is preferably 0.1 to 25% by mass.
The range of use of the graft crossing agent (I-C4) is preferably 0.1 to 5% by mass.
(However, (I−C1) + (I−C2) + (I−C3) + (I−C4) = 100 mass%)

  The amount of the second intermediate polymer (IC) in the rubber-containing multistage polymer (I) (100% by mass) is preferably 2 to 20% by mass. Moreover, it is preferable that the latex particle diameter in the 2nd intermediate polymer (IC) stage in manufacture of rubber-containing multistage polymer (I) is 0.03-0.2 micrometer.

Rigid polymer (ID) includes alkyl methacrylate (ID1) having an alkyl group having 4 or less carbon atoms, alkyl acrylate (ID2) having an alkyl group having 8 or less carbon atoms, and aromatic vinyl monomer A polymer having a Tg of 50 ° C. or higher obtained by polymerizing (I-D3).
The use range of the alkyl methacrylate (I-D1) having an alkyl group having 4 or less carbon atoms is preferably 51 to 99.8% by mass in terms of heat resistance of the resulting colored acrylic resin film.
The use range of the alkyl acrylate (I-D2) having an alkyl group having 8 or less carbon atoms is preferably 0.1 to 48.9% by mass.
The use range of the aromatic vinyl monomer (I-D3) is preferably 0.1 to 25% by mass.
(However, (I−D1) + (I−D2) + (I−D3) = 100 mass%)

It is preferable that Tg of a hard polymer (ID) is 50 degreeC or more. When Tg is 50 ° C. or higher, the resulting colored acrylic resin film tends to have good heat resistance.
The amount of the hard polymer (ID) in the rubber-containing multistage polymer (I) (100% by mass) is preferably 10 to 80% by mass in terms of heat resistance of the resulting colored acrylic resin film. .

Here, Tg of a polymer is calculated | required by the following Fox formula, for example in the case of the copolymer which consists of monomer a, b, c ....
1 / Tg = ma / Tga + mb / Tgb + mc / Tgc ...
Tg: Tg [K] of copolymer, ma: mass fraction of monomer a, Tga: Tg [K] of homopolymer obtained from monomer a, mb: mass fraction of monomer b, Tgb: Tg [K] of the homopolymer obtained from the monomer b, mc: Mass fraction of the monomer c, Tgc: Tg [K] of the homopolymer obtained from the monomer c.

  The alkyl methacrylate (I-A1) having an alkyl group having 4 or less carbon atoms may be linear or branched, and examples thereof include butyl methacrylate, propyl methacrylate, ethyl methacrylate, and methyl methacrylate. These may be used alone or in combination of two or more. Of these, methyl methacrylate is preferable from the viewpoint of transparency of the colored acrylic resin film.

  Examples of the alkyl acrylate (I-A2) having an alkyl group having 8 or less carbon atoms include methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, 2-ethylhexyl acrylate, and the like. These may be used alone or in combination of two or more. Of these, butyl acrylate is preferred from the viewpoint of Tg.

  Examples of the aromatic vinyl monomer (I-A3) include styrene, α-methylstyrene, paramethylstyrene, and the like. These may be used alone or in combination of two or more. Of these, styrene is preferable from the viewpoint of economy.

  Examples of the polyfunctional monomer (I-A4) include alkylene glycol dimethacrylates such as ethylene glycol dimethacrylate, 1,3-butylene dimethacrylate, 1,4-butylene glycol dimethacrylate, and propylene glycol dimethacrylate; Examples thereof include polyvinylbenzene such as benzene and trivinylbenzene; alkylene glycol diacrylate and the like. These may be used alone or in combination of two or more. Of these, alkylene glycol dimethacrylate is preferred, and 1,3-butylene glycol dimethacrylate is more preferred.

  Examples of the graft crossing agent (I-A5) include copolymerizable α, β-unsaturated monocarboxylic acid or dicarboxylic acid allyl ester, methallyl ester, crotyl ester, triallyl cyanurate, triallyl isocyanurate, and the like. Is mentioned. These may be used alone or in combination of two or more. Of these, allyl methacrylate and triallyl cyanurate are preferable.

Examples of the alkyl acrylate (I-B1) having an alkyl group having 8 or less carbon atoms include the alkyl acrylates represented by (I-A2). These may be used alone or in combination of two or more.
Examples of the aromatic vinyl monomer (I-B2) include the aromatic vinyl monomer represented by (I-A3). These may be used alone or in combination of two or more.

Examples of the polyfunctional monomer (I-B3) include the polyfunctional monomer represented by (I-A4). These may be used alone or in combination of two or more. Of these, alkylene glycol dimethacrylate is preferred, and 1,3-butylene glycol dimethacrylate is more preferred.
Examples of the graft crossing agent (I-B4) include the graft crossing agent represented by (I-A5). These may be used alone or in combination of two or more. Of these, allyl methacrylate and triallyl cyanurate are preferable.

  The monomer (I-B5) having a copolymerizable double bond is a monomer having a double bond copolymerizable with the above-mentioned monomer other than the above-mentioned monomer. Examples of the monomer (I-B5) include acrylic monomers such as lower alkoxy acrylate, cyanoethyl acrylate, acrylamide, acrylic acid, and methacrylic acid, alkyl-substituted styrene, acrylonitrile, and methacrylonitrile. These may be used alone or in combination of two or more.

  Examples of the monomer and graft crossing agent constituting the second intermediate polymer (IC) and the hard polymer (ID) include the elastic polymer (IA) and the first intermediate polymer (IB). ) And the like. These may be used alone or in combination of two or more.

The final latex particle diameter of the rubber-containing multistage polymer (I) is preferably 0.03 to 0.2 μm, more preferably 0.04 to 0.15 μm, and particularly preferably 0.05 to 0.1 μm. When the final latex particle size is too large, not only the transparency of the colored acrylic resin film is lowered, but also the transparency may be changed due to a temperature change. When used as a skin material for a retroreflective sheeting outdoors such as a road sign, if the transparency changes due to a change in the outside air temperature, there is a possibility that the reflection performance is lowered and the hue is changed. On the other hand, if the particle size is too small, the impact resistance may be reduced.
The acrylic resin used as the skin material of the retroreflective sheet is preferably highly transparent in terms of reflection performance, and is mainly used outdoors as a road sign or the like, so that it is preferable to have high impact resistance.

  Furthermore, in order to reduce the temperature dependence of the total light transmittance and the haze value, the amount of alkyl methacrylate units having 4 or less carbon atoms in each layer in the rubber-containing multistage polymer (I) is reduced by the first intermediate polymer ( The amount of alkyl methacrylate units monotonically increasing from IB) toward the second intermediate polymer (IC) and hard polymer (ID), and occupying the elastic polymer (IA). It is preferable that it is more than the quantity which occupies for 1 intermediate polymer (IB).

  In addition, aromatic vinyl monomers and carbon in the layers (IA), (IB), (IC), and (ID) made of each polymer of the rubber-containing multistage polymer (I). The mass ratio (aromatic vinyl monomer / alkyl acrylate) to the alkyl acrylate having an alkyl group of several 8 or less is preferably 5/95 to 50/50, and 10/90 to 30/70. Is more preferable. As the mass ratio goes away from this range, the transparency decreases, and the reflection performance tends to decrease when used as a skin material for a retroreflective sheet.

As a method for producing the rubber-containing multistage polymer (I), a sequential multistage polymerization method by an emulsion polymerization method is the most suitable polymerization method. The production of the rubber-containing multistage polymer (I) is not particularly limited. For example, the emulsion-suspension polymerization method may be used in which emulsion polymerization is followed by conversion to a suspension polymerization system when each hard polymer is polymerized. It can be carried out.
In addition, when the rubber-containing multistage polymer (I) is produced by emulsion polymerization, an emulsion is prepared by previously mixing a monomer mixture that gives the elastic polymer (IA) with water and a surfactant. After the emulsion is supplied to the reactor and polymerized, the monomer mixture constituting the remaining layers is sequentially supplied to the reactor and polymerized.

  When the monomer mixture that gives the elastic polymer (IA) is mixed with water and a surfactant in advance and supplied to the reactor, the emulsion is polymerized, and particularly when dispersed in acetone. In addition, a rubber-containing multistage polymer in which the number of particles having a diameter of 55 μm or more present in the dispersion is 0 to 50 per 100 g of the rubber-containing multistage polymer (I) can be easily obtained. The colored acrylic resin film using the rubber-containing multistage polymer (I) thus obtained as a raw material has a characteristic that the number of fish eyes in the film is small, and is preferable because the appearance is good.

  Examples of the surfactant used in preparing the emulsion include anionic, cationic, and nonionic surfactants. Of these, anionic surfactants are particularly preferred. Examples of the anionic surfactant include rosin soap; potassium oleate, sodium stearate, sodium myristate, sodium N-lauroyl sarcosinate, dipotassium alkenyl succinate, and the like; sulfate salts such as sodium lauryl sulfate Sulfonic acid salts such as sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, sodium alkyldiphenyl ether disulfonate; phosphate esters such as polyoxyethylene alkylphenyl ether sodium phosphate; polyoxyethylene alkyl ether sodium phosphate And phosphoric acid ester salts. Of these, phosphate ester salts such as polyoxyethylene alkyl ether sodium phosphates are particularly preferred from the viewpoint of ecological protection from endocrine disrupting chemicals that have become a problem in recent years.

  Preferable specific examples of the surfactant include NC-718 manufactured by Sanyo Chemical Industries, Ltd., Phosphanol LS-529, Phosphanol RS-610NA, Phosphanol RS- manufactured by Toho Chemical Industry Co., Ltd. 620NA, Phosphanol RS-630NA, Phosphanol RS-640NA, Phosphanol RS-650NA, Phosphanol RS-660NA, Latemul P-0404, Latemul P-0405, Latemul P-0406 manufactured by Kao Corporation Latemul P-0407 and the like.

  As a method for preparing an emulsion, a method of charging a monomer mixture into water and then adding a surfactant; a method of charging a surfactant into water and then charging the monomer mixture; a monomer For example, a method of charging water after charging a surfactant into the mixture may be used. Among these, the rubber-containing multistage polymer (I) is a method in which a monomer is charged in water and then a surfactant is charged, and a method in which a surfactant mixture is charged and then a monomer mixture is charged. As a method for obtaining

In addition, as a mixing device for preparing an emulsion prepared by mixing a monomer mixture that gives the elastic polymer (IA) constituting the rubber-containing multistage polymer (I) with water and a surfactant. These include a stirrer equipped with a stirring blade; various forced emulsifiers such as a homogenizer and a homomixer; a membrane emulsifier.
Further, the emulsion to be prepared may have either a W / O type or an O / W type dispersion structure, particularly an O / W type in which oil droplets of a monomer mixture are dispersed in water, and oil droplets in a dispersed phase. The diameter is preferably 100 μm or less.

  Elastic polymer (IA), first intermediate polymer (IB), second intermediate polymer (IC), and hard polymer (ID) constituting rubber-containing multistage polymer (I) As the polymerization initiator used when forming (), known ones can be used. As the addition method, a method of adding to one or both of the aqueous phase and the monomer phase can be employed. Examples of the polymerization initiator include a peroxide, an azo initiator, or a redox initiator in which an oxidizing agent / reducing agent is combined. Of these, redox initiators are preferable, and sulfoxylate initiators in which ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, longalite, and hydroperoxide are combined are particularly preferable.

In particular, an emulsion prepared by mixing a monomer mixture that gives the above-mentioned elastic polymer (IA) with water and a surfactant is supplied to the reactor and polymerized, and then the first intermediate polymer (I -B), a monomer mixture that gives the second intermediate polymer (IC) and the hard polymer (ID) is fed to the reactor in order, and in the polymerization method, ferrous sulfate / ethylenediamine The aqueous solution containing tetrasodium disodium salt and Rongalite is heated to the polymerization temperature, and then the prepared emulsion is supplied to the reactor for polymerization, and then a first intermediate polymer containing a polymerization initiator such as peroxide ( IB), a second intermediate polymer (IC), and a monomer mixture that gives a hard polymer (ID) are sequentially fed to the reactor and polymerized to form a rubber-containing multistage polymer ( The most preferred method for obtaining I).
In addition, although superposition | polymerization temperature changes with kinds and quantity of the polymerization initiator to be used, 40-120 degreeC is preferable and 60-95 degreeC is more preferable.

(Thermoplastic polymer (II))
The thermoplastic polymer (II) includes 50 to 100% by mass of a structural unit derived from an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, and a structural unit derived from another vinyl monomer copolymerizable therewith. It is a polymer comprising 0 to 50% by mass and having a reduced viscosity (measured at 25 ° C. of 0.1 g of polymer dissolved in 100 ml of chloroform) of 0.1 l / g or less.

Examples of the alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Of these, methyl methacrylate is most preferred.
Examples of other vinyl monomers include alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, and 2-ethylhexyl acrylate; aromatic vinyl monomers such as styrene, α-methyl styrene, and paramethyl styrene Body; vinylcyan compounds such as acrylonitrile and methacrylonitrile.

The reduced viscosity of the thermoplastic polymer (II) is 0.1 l / g or less. When the reduced viscosity exceeds 0.1 l / g, the fluidity is deteriorated, which is not preferable in terms of film moldability.
The polymerization method for obtaining the thermoplastic polymer (II) is not particularly limited, and various methods such as a known suspension polymerization method and emulsion polymerization method are applied.
The thermoplastic polymer (II) is industrially available as the Mitsubishi Danyon BR series.

(Rubber-containing multistage polymer (III))
The rubber-containing multistage polymer (III) is a rubber-containing multistage polymer arranged in the order of an elastic polymer (III-A), an intermediate polymer (III-B), and a hard polymer (III-C) from the center. .
The rubber-containing multistage polymer (III) may be mixed with the thermoplastic polymer (II) as long as the film properties are not impaired.

  The elastic polymer (III-A) has 50 to 99.9% by mass of a structural unit derived from an alkyl acrylate (III-A1) having an alkyl group having 1 to 8 carbon atoms and an alkyl group having 1 to 4 carbon atoms. 0 to 49.9 mass% of structural units derived from alkyl methacrylate (III-A2), 0 to 20 mass% of structural units derived from another monomer (III-A3) having a copolymerizable double bond, It is a polymer composed of 0 to 10% by mass of structural units derived from the polyfunctional monomer (III-A4) and 0.1 to 10% by mass of structural units derived from the graft crossing agent (III-A5) (however, (III-A1) + (III-A2) + (III-A3) + (III-A4) + (III-A5) = 100% by mass).

  The intermediate polymer (III-B) has 9.9 to 90% by mass of a structural unit derived from an alkyl acrylate (III-B1) having an alkyl group having 1 to 8 carbon atoms and an alkyl group having 1 to 4 carbon atoms. 9.9 to 90% by mass of a structural unit derived from alkyl methacrylate (III-B2), 0 to 20% by mass of a structural unit derived from another monomer (III-B3) having a copolymerizable double bond, It is composed of 0 to 10% by mass of structural units derived from the polyfunctional monomer (III-B4) and 0.1 to 10% by mass of structural units derived from the graft crossing agent (III-B5), and an elastic polymer ( (III-A) is a polymer having a different composition (however, (III-B1) + (III-B2) + (III-B3) + (III-B4) + (III-B5)) = 100% by mass is there.).

  The hard polymer (III-C) is an alkyl acrylate having 80 to 100% by mass of structural units derived from an alkyl methacrylate (III-C1) having an alkyl group having 1 to 4 carbon atoms and an alkyl group having 1 to 8 carbon atoms. A polymer comprising 0 to 20% by mass of the structural unit derived from (III-C2) and 0 to 20% by mass of the structural unit derived from another monomer (III-C3) having a copolymerizable double bond. (However, (III-C1) + (III-C2) + (III-C3) = 100 mass%).

  The alkyl acrylate (III-A1) having an alkyl group having 1 to 8 carbon atoms may be either linear or branched. Specific examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate and the like. These may be used alone or in combination of two or more. Of these, n-butyl acrylate is preferred.

  The alkyl methacrylate (III-A2) having 1 to 4 carbon atoms may be linear or branched. Specific examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate and the like. These may be used alone or in combination of two or more. Of these, methyl methacrylate is preferred.

  Examples of other monomers (III-A3) having a copolymerizable double bond include acrylic monomers such as lower alkoxy acrylate, cyanoethyl acrylate, acrylamide, acrylic acid, methacrylic acid; styrene, alkyl-substituted Styrene, acrylonitrile, methacrylonitrile, etc. are mentioned.

  The polyfunctional monomer (III-A4) can be used as necessary. The polyfunctional monomer (III-A4) is defined as a monomer having two or more copolymerizable double bonds in one molecule. Specific examples thereof include alkylene glycol dimethacrylates such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate and propylene glycol dimethacrylate; polyvinylbenzene such as divinylbenzene and trivinylbenzene. Etc. Of these, alkylene glycol dimethacrylate is preferred, and 1,3-butylene glycol dimethacrylate is particularly preferred. Even if the polyfunctional monomer does not act at all, as long as the grafting agent is present, a fairly stable rubber-containing multistage polymer is obtained. For example, when the hot strength or the like is strictly required, a polyfunctional monomer may be arbitrarily added depending on the purpose of addition.

The graft crossing agent (III-A5) is defined as a monomer having two or more different copolymerizable double bonds in one molecule. Specific examples thereof include allyl, methallyl, or crotyl ester of copolymerizable α, β-unsaturated carboxylic acid or dicarboxylic acid; triallyl cyanurate, triallyl isocyanurate, and the like. Among these, acrylic acid, methacrylic acid, maleic acid, or fumaric acid acrylic ester is preferable, and methacrylic acid allyl ester is particularly preferable because of its excellent effect. In the graft crossing agent (III-A5), mainly the conjugated unsaturated bond of the ester reacts much faster than the allyl group, methallyl group, or crotyl group and chemically bonds. A substantial portion of the allyl, methallyl, or crotyl group works effectively during the polymerization of the next layer polymer to provide a graft bond between adjacent two layers.
In addition, you may superpose | polymerize in presence of a chain transfer agent.

  The content of the structural unit derived from the alkyl acrylate (III-A1) having an alkyl group having 1 to 8 carbon atoms in 100% by mass of all monomer units constituting the elastic polymer (III-A) is rubber-containing. From the viewpoint of physical properties such as film moldability and impact resistance of the multistage polymer (III), it is 50 to 99.9% by mass, preferably 55 to 77.9% by mass, particularly 60 to 69.9% by mass. preferable.

  Content of the structural unit derived from the alkyl methacrylate (III-A2) which has a C1-C4 alkyl group in 100 mass% of all the monomer units which comprise an elastic polymer (III-A) is 0- It is 49.9 mass%, More preferably, it is 20 mass% or more, Most preferably, it is 30 mass% or more. Further, it is more preferably 44.9% by mass or less, and most preferably 39.9% by mass or less.

  The structural unit derived from the other monomer (III-A3) having a copolymerizable double bond in 100% by mass of all the monomer units constituting the elastic polymer (III-A) is 0-20. It is mass%, and 0-15 mass% is preferable.

  Content of the structural unit derived from the polyfunctional monomer (III-A4) in 100 mass% of all monomer units constituting the elastic polymer (III-A) is 0 to 10 mass%, 0.1-6 mass% is preferable.

Content of the structural unit derived from the graft crossing agent (III-A5) in 100% by mass of all monomer units constituting the elastic polymer (III-A) is 0.1 to 10% by mass, 0 0.5-2 mass% is preferable. When the content is 0.1% by mass or more, the obtained rubber-containing multistage polymer (III) can be formed into a film without deteriorating optical properties such as transparency. When the content is 10% by mass or less, sufficient flexibility and toughness can be imparted to the rubber-containing multistage polymer (III).
The content of each structural unit in the elastic polymer (III-A) is in the above range, and the transparency and impact resistance of the colored acrylic resin film obtained by molding the rubber-containing multistage polymer (III). From the viewpoint of physical properties of

From the viewpoint of impact resistance of the colored acrylic resin film obtained by molding the rubber-containing multistage polymer (III), the Tg of the elastic polymer (III-A) alone is an intermediate polymer (III-B) alone described later. Is preferably less than 25 ° C, more preferably 10 ° C or less, and particularly preferably 0 ° C or less.
The content of the elastic polymer (III-A) in the rubber-containing multistage polymer (III) (100% by mass) is the transparency of the colored acrylic resin film obtained by molding the rubber-containing multistage polymer (III). The point is preferably 15 to 50% by mass, and more preferably 15 to 35% by mass. In this case, it is advantageous in terms of reflection performance when the rubber-containing multistage polymer (III) is used as a skin material for the retroreflective sheet.

The elastic polymer (III-A) may be a single layer or two layers. Of these, those consisting of two layers are more preferred. Moreover, it is preferable that the component ratios of the monomer units of the two layers in the elastic polymer (III-A) are different from each other.
When the elastic polymer (III-A) consists of two layers, from the viewpoint of impact resistance and transparency of the colored acrylic resin film obtained by molding the rubber-containing multistage polymer (III), the inner layer (III-A The Tg of -1) is preferably lower than the Tg of the outer layer (III-A-2). Specifically, the Tg of the inner layer (III-A-1) is preferably less than −30 ° C. from the viewpoint of impact resistance, and the Tg of the outer layer (III-A-2) is from the viewpoint of transparency— 15 ° C to 10 ° C is preferred.

In addition, from the viewpoint of transparency, the content of the inner layer (III-A-1) in the elastic polymer (III-A) (100 mass%) is preferably 1 to 20 mass%, and the outer layer (III-A The content of A-2) is preferably 80 to 99% by mass. The acrylic resin used as a skin material of a retroreflective sheet mainly used outdoors, such as a road sign, is preferably high in transparency.
Preferred examples of the rubber-containing multistage polymer when the elastic polymer (III-A) is composed of two layers include the polymers described in JP-B-62-19309.

  The alkyl acrylate (III-B1) having an alkyl group having 1 to 8 carbon atoms may be either linear or branched. Specific examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate and the like. These may be used alone or in combination of two or more. Of these, methyl acrylate and n-butyl acrylate are preferred.

  The alkyl methacrylate (III-B2) having an alkyl group having 1 to 4 carbon atoms may be linear or branched. Specific examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate and the like. These may be used alone or in combination of two or more. Of these, methyl methacrylate is preferred.

  Other monomers (III-B3) having a copolymerizable double bond include acrylic monomers such as lower alkoxy acrylate, cyanoethyl acrylate, acrylamide, acrylic acid, methacrylic acid; styrene, alkyl-substituted styrene, Examples include acrylonitrile and methacrylonitrile.

  The polyfunctional monomer (III-B4) may be used as necessary. Specific examples thereof include alkylene glycol dimethacrylates such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate and propylene glycol dimethacrylate; polyvinylbenzene such as divinylbenzene and trivinylbenzene. Etc. Of these, alkylene glycol dimethacrylate is preferred, and 1,3-butylene glycol dimethacrylate is particularly preferred. Even when the polyfunctional monomer does not act at all, as long as the grafting agent is present, a fairly stable rubber-containing multistage polymer is obtained. For example, when the hot strength or the like is strictly required, a polyfunctional monomer may be arbitrarily added depending on the purpose of addition.

Examples of the grafting agent (III-B5) include copolymerizable α, β-unsaturated carboxylic acid or dicarboxylic acid allyl, methallyl, or crotyl ester; triallyl cyanurate, triallyl isocyanurate, and the like. Among these, acrylic acid, methacrylic acid, maleic acid, or fumaric acid acrylic ester is preferable, and methacrylic acid allyl ester is particularly preferable because of its excellent effect. In the graft crossing agent (III-B5), mainly the conjugated unsaturated bond of the ester reacts much faster than the allyl group, methallyl group, or crotyl group, and chemically bonds. A substantial portion of the allyl, methallyl, or crotyl group works effectively during the polymerization of the next layer polymer to provide a graft bond between adjacent two layers.
In addition, you may superpose | polymerize in presence of a chain transfer agent.

  The content of the structural unit derived from alkyl acrylate (III-B1) having an alkyl group having 1 to 8 carbon atoms in 100% by mass of all monomer units constituting the intermediate polymer (III-B) is 9. 9-90% by mass. From the viewpoint of transparency of the colored acrylic resin film obtained by molding the rubber-containing multistage polymer (III), it is more preferably 19.9% by mass or more, and most preferably 29.9% by mass or more. Further, it is more preferably 60% by mass or less, and most preferably 50% by mass or less.

  Content of the structural unit derived from the alkyl methacrylate (III-B2) which has a C1-C4 alkyl group in 100 mass% of all the monomer units which comprise an intermediate polymer (III-B) is 9. 9-90% by mass. From the viewpoint of transparency of the colored acrylic resin film obtained by molding the rubber-containing multistage polymer (III), it is more preferably 39.9% by mass or more, and most preferably 49.9% by mass or more. Further, it is more preferably 80% by mass or less, and most preferably 70% by mass or less.

Content of the structural unit derived from the other monomer (III-B3) having a copolymerizable double bond in 100% by mass of all the monomer units constituting the intermediate polymer (III-B) is: It is 0-20 mass%, and 0-15 mass% is preferable.
Content of the structural unit derived from the polyfunctional monomer (III-B4) in 100 mass% of all monomer units constituting the intermediate polymer (III-B) is 0 to 10 mass%, 0-6 mass% is preferable.
Content of the structural unit derived from the graft crossing agent (III-B5) in 100% by mass of all monomer units constituting the intermediate polymer (III-B) is 0.1 to 10% by mass, 0 0.5-2 mass% is preferable. When the content is 0.1% by mass or more, the obtained rubber-containing multistage polymer (III) can be formed into a film without deteriorating optical properties such as transparency. When the content is 10% by mass or less, sufficient flexibility and toughness can be imparted to the rubber-containing multistage polymer (III).

  The composition of the monomer unit of the intermediate polymer (III-B) is preferably different from the composition of the monomer unit of the elastic polymer (III-A). When the compositions of these polymers are different, film properties such as impact resistance and transparency can be satisfied. In the present invention, “different composition” refers to alkyl acrylate, alkyl methacrylate, other monomers having a copolymerizable double bond, a polyfunctional monomer, and a graft crossing agent. The type and / or amount is different.

  The Tg of the intermediate polymer (III-B) alone is preferably 25 to 100 ° C. When Tg is 25 ° C. or higher, the heat resistance, scratch resistance and transparency of the colored acrylic resin film obtained by molding the rubber-containing multistage polymer (III) are improved. More preferably, it is 40 degreeC or more, Most preferably, it is 50 degreeC or more. Moreover, when Tg is 100 degrees C or less, rubber-containing multistage polymer (III) with favorable film forming property is obtained. More preferably, it is 80 degrees C or less, Most preferably, it is 70 degrees C or less.

  Further, the content of the intermediate polymer (III-B) in the rubber-containing multistage polymer (III) (100% by mass) is preferably 5 to 35% by mass, and more preferably 15 to 20% by mass. If it is in this range, functions necessary as an intermediate, for example, transparency can be expressed.

  The alkyl methacrylate (III-C1) having an alkyl group having 1 to 4 carbon atoms may be either linear or branched. Specific examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate and the like. These may be used alone or in combination of two or more. Of these, methyl methacrylate is preferred.

  The alkyl acrylate (III-C2) having an alkyl group having 1 to 8 carbon atoms may be either linear or branched. Specific examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate and the like. These may be used alone or in combination of two or more. Of these, methyl acrylate and n-butyl acrylate are preferred.

  Other monomers (III-C3) having a copolymerizable double bond include acrylic monomers such as lower alkoxy acrylate, cyanoethyl acrylate, acrylamide, acrylic acid, methacrylic acid; styrene, alkyl-substituted styrene, Examples include acrylonitrile and methacrylonitrile.

Content of the structural unit derived from the alkyl methacrylate (III-C1) which has a C1-C4 alkyl group in 100 mass% of all the monomer units which comprise a hard polymer (III-C) is 80- 100% by mass, more preferably 90% by mass or more, and most preferably 93% by mass or more. Moreover, it is 99 mass% or less more preferably.
Content of the structural unit derived from the alkyl acrylate (III-C2) which has a C1-C8 alkyl group in 100 mass% of all the monomer units which comprise a hard polymer (III-C) is 0-. It is 20 mass%, More preferably, it is 1 mass% or more. Further, it is more preferably 10% by mass or less, and most preferably 7% by mass or less.

Content of the structural unit derived from the monomer (III-C3) having a copolymerizable double bond in 100% by mass of all the monomer units constituting the hard polymer (III-C) is 0 to It is 20 mass%, and 0-15 mass% is preferable.
The content of each constituent unit of the hard polymer (III-C) is in the above range, and the film moldability and transparency of the colored acrylic resin film obtained by molding the rubber-containing multistage polymer (III) It is preferable from the viewpoint.

  Further, a chain transfer agent may be used during the polymerization of the monomers ((III-C1) to (III-C3)) to adjust the molecular weight of the hard polymer (III-C). This chain transfer agent is usually selected from those used for radical polymerization. Specific examples include alkyl mercaptans having 2 to 20 carbon atoms, mercapto acids, thiophenol, carbon tetrachloride and the like. These may be used alone or in combination of two or more. The content of the chain transfer agent is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the monomers ((III-C1) to (III-C3)). More preferably, it is 0.2 mass part or more, Most preferably, it is 0.4 mass part or more.

  The Tg of the hard polymer (III-C) alone is preferably 60 ° C. or higher. When Tg is 60 ° C. or higher, a colored acrylic resin film having good film properties such as scratch resistance when the rubber-containing multistage polymer (III) is formed into a film can be obtained. More preferably, it is 80 degreeC or more, Most preferably, it is 90 degreeC or more.

  Further, the content of the hard polymer (III-C) in the rubber-containing multistage polymer (III) (100% by mass) is preferably 15 to 80% by mass, and preferably 45 to 80% by mass in terms of film properties. More preferred is 45 to 70% by mass.

As a method for producing the rubber-containing multistage polymer (III), a sequential multistage polymerization method by an emulsion polymerization method is the most suitable polymerization method as with the rubber-containing multistage polymer (I). The production of the rubber-containing multistage polymer (III) is not particularly limited. For example, after the emulsion polymerization, an emulsion suspension polymerization method in which each of the hard polymers is converted into a suspension polymerization system at the time of polymerization. It can be carried out.
In addition, when the rubber-containing multistage polymer (III) is produced by emulsion polymerization in the same manner as the rubber-containing multistage polymer (I), part or all of the monomer mixture that gives the elastic polymer (III-A) Are mixed with water and a surfactant in advance to prepare an emulsion, and after the emulsion is supplied to the reactor and polymerized, the monomer mixture constituting the remaining layers is supplied to the reactor in order, A polymerization method is preferred.

  When the monomer mixture that gives the elastic polymer (III-A) is mixed with water and a surfactant in advance and supplied to the reactor, the emulsion is polymerized, particularly when dispersed in acetone In addition, a rubber-containing multistage polymer in which the number of particles having a diameter of 55 μm or more present in the dispersion is 0 to 50 per 100 g of the rubber-containing multistage polymer (III) can be easily obtained. A colored acrylic resin film using the rubber-containing multistage polymer (III) thus obtained as a raw material has a characteristic that the number of fish eyes in the film is small, and is preferable because the appearance is good.

As the surfactant used in preparing the emulsion, the same surfactant as that used in preparing the emulsion with the rubber-containing multistage polymer (I) can be used.
The method for preparing the emulsion is also preferably the same method as for the rubber-containing multistage polymer (I).
Also, as a mixing device for preparing an emulsion prepared by mixing a monomer mixture that gives the elastic polymer (III-A) constituting the rubber-containing multistage polymer (III) with water and a surfactant. Examples thereof include an apparatus used for preparing an emulsion for producing a rubber-containing multistage polymer (I).
Further, the emulsion to be prepared may have either a W / O type or an O / W type dispersion structure, particularly an O / W type in which oil droplets of a monomer mixture are dispersed in water, and oil droplets in a dispersed phase. The diameter is preferably 100 μm or less.

  As a polymerization initiator used in forming the elastic polymer (III-A), the intermediate polymer (III-B), and the hard polymer (III-C) constituting the rubber-containing multistage polymer (III) Well-known ones can be used. As the addition method, a method of adding to one or both of the aqueous phase and the monomer phase can be employed. Examples of the polymerization initiator include a peroxide, an azo initiator, or a redox initiator in which an oxidizing agent / reducing agent is combined. Of these, redox initiators are preferable, and sulfoxylate initiators in which ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, longalite, and hydroperoxide are combined are particularly preferable.

In particular, an emulsion prepared by mixing a monomer mixture giving the above-mentioned elastic polymer (III-A) with water and a surfactant is supplied to the reactor and polymerized, and then the intermediate polymer (III-B) is prepared. ) And a monomer mixture giving a hard polymer (III-C) are sequentially fed to the reactor, and in the polymerization method, an aqueous solution containing ferrous sulfate, ethylenediaminetetraacetic acid disodium salt and Rongalite is used as the polymerization temperature. The temperature of the emulsion is increased to a temperature, and the prepared emulsion is supplied to the reactor for polymerization, and then an intermediate polymer (III-B) and a hard polymer (III-C) containing a polymerization initiator such as peroxide are obtained. The method of sequentially supplying the monomer mixture to the reactor and polymerizing is the most preferable method for obtaining the rubber-containing multistage polymer (III).
In addition, although superposition | polymerization temperature changes with kinds and quantity of the polymerization initiator to be used, 40-120 degreeC is preferable and 60-95 degreeC is more preferable.

(Rubber-containing multistage polymer (IV))
The rubber-containing multistage polymer (IV) is a rubber-containing multistage polymer having an alkyl acrylate, an alkyl methacrylate, and a graft crossing agent, which are known in the art, as constituent components of the polymer.

  More specific examples of the rubber-containing multistage polymer (IV) are preferably an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and / or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms and a graft crossing agent. A first elastic polymer (IV-A) as a constituent component of the coal, a second elastic polymer (IV-A) having at least an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and a graft crossing agent as constituent components of the polymer B), an intermediate polymer (IV-D) comprising at least an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and / or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms and a graft crossing agent as a constituent of the polymer. ), At least a polymer having an alkyl group having 1 to 4 carbon atoms. Rigid polymer comprising as a component (IV-C) are those which are polymerized in this order.

  The first elastic polymer (IV-A) constituting the preferred rubber-containing multistage polymer (IV) is an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms ( IV-A1), another monomer having a copolymerizable double bond used as necessary (IV-A2), a multifunctional monomer used as needed (IV-A3), A polymer comprising a graft-crossing agent (IV-A4) as a constituent component, which is polymerized first when the rubber-containing multistage polymer (IV) is polymerized.

  Of the components (IV-A1) constituting the first elastic polymer (IV-A), the alkyl acrylate having an alkyl group having 1 to 8 carbon atoms may be either linear or branched. Specific examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate and the like. These may be used alone or in combination of two or more. Among these, those having a low Tg are more preferable. In addition, among the components (IV-A1), the alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms may be either linear or branched. Specific examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate and the like. These may be used alone or in combination of two or more.

  The alkyl (meth) acrylate (IV-A1) is preferably used within a range of 80 to 100 parts by mass with respect to 100 parts by mass of the total amount of components (IV-A1) to (IV-A3). Further, the alkyl (meth) acrylate of the type used in the first elastic polymer (IV-A) is unified when the polymers (IV-A) to (IV-D) are subsequently polymerized. Most preferably it is used. However, in each polymer of (IV-A) to (IV-D), two or more kinds of alkyl (meth) acrylates may be mixed, or another kind of acrylate may be used. “(Meth) acrylate” means acrylate and / or methacrylate.

  The other monomer (IV-A2) having a copolymerizable double bond constituting the first elastic polymer (IV-A) may be used as necessary. Specific examples thereof include acrylate monomers such as higher alkyl acrylate, lower alkoxy acrylate and cyanoethyl acrylate having an alkyl group having 9 or more carbon atoms, acrylamide, acrylic acid, methacrylic acid, styrene, alkyl-substituted styrene, acrylonitrile, methacrylo A nitrile etc. are mentioned. The monomer (IV-A2) is preferably used in the range of 0 to 20 parts by mass with respect to 100 parts by mass in total of the components (IV-A1) to (IV-A3).

  What is necessary is just to use the polyfunctional monomer (IV-A3) which comprises a 1st elastic polymer (IV-A) as needed. Specific examples thereof include alkylene glycol dimethacrylates such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, and propylene glycol dimethacrylate. Further, polyvinyl benzene such as divinyl benzene and trivinyl benzene can also be used. Moreover, even when the polyfunctional monomer (IV-A3) does not act at all, a rubber-containing multistage polymer is obtained which is considerably stable as long as the graft crossing agent is present. For example, when the hot strength or the like is strictly required, it may be arbitrarily used depending on the purpose of addition. The polyfunctional monomer (IV-A3) is preferably used in the range of 0 to 10 parts by mass with respect to 100 parts by mass in total of the components (IV-A1) to (IV-A3).

  Examples of the graft crossing agent (IV-A4) constituting the first elastic polymer (IV-A) include allyl, methallyl or crotyl ester of copolymerizable α, β-unsaturated carboxylic acid or dicarboxylic acid. . Particularly preferred are acrylic esters of acrylic acid, methacrylic acid, maleic acid or fumaric acid. Among these, allyl methacrylate has an excellent effect. In addition, triallyl cyanurate, triallyl isocyanurate and the like are also effective. Graft-crossing agent (IV-A4) reacts much faster than the allyl group, methallyl group or crotyl group and chemically bonds mainly with the conjugated unsaturated bond of the ester.

  The amount of the graft crossing agent (IV-A4) used is extremely important, and is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the total amount of the components (IV-A1) to (IV-A3). -2 mass parts is more preferable. The lower limit of these ranges is significant in terms of the effective amount of graft bonds. Further, the upper limit value moderately suppresses the amount of reaction with the second elastic polymer (IV-B) formed in the second stage and reduces the elasticity of the two-stage crosslinked rubber elastic body having a two-stage elastic body structure. Significant in terms of prevention.

  The content of the first elastic polymer (IV-A) in 100% by mass of the preferred rubber-containing multistage polymer (IV) is preferably 5 to 35% by mass, and more preferably 5 to 15% by mass. Further, it is preferable that the content is less than the content of the second elastic polymer (IV-B).

  The second elastic polymer (IV-B) constituting the preferred rubber-containing multistage polymer (IV) is a main component that imparts rubber elasticity to the rubber-containing multistage polymer (IV), and is an alkyl having 1 to 8 carbon atoms. An alkyl acrylate having a group (IV-B1), another monomer having a copolymerizable double bond (IV-B2) used if necessary, and a polyfunctional monomer (optional) This is a second elastic polymer (IV-B) comprising IV-B3) and a graft crossing agent (IV-B4) as constituent components.

  Preferred specific examples of the components (IV-B1) to (IV-B4) are the same as those described for the components (IV-A1) to (IV-A4) of the first elastic polymer (IV-A), respectively. . The amount of component (IV-B1) used is preferably 80 to 100 parts by mass. The amount of component (IV-B2) used is preferably 0 to 20 parts by mass. The amount of component (IV-B3) used is preferably 0 to 10 parts by mass. The amount of component (IV-B4) used is preferably 0.1 to 5 parts by mass. The range of these amounts used is based on a total of 100 parts by mass of components (IV-B1) to (IV-B3).

  The Tg of the second elastic polymer (IV-B) alone is preferably 0 ° C. or lower, and more preferably −30 ° C. or lower. When this Tg is 0 ° C. or lower, there is a tendency to exhibit excellent elasticity. The content of the second elastic polymer (IV-B) in 100% by mass of the preferred rubber-containing multistage polymer (IV) is preferably 10 to 45% by mass, and the content of the first elastic polymer (IV-A) More than the amount is preferred.

  The hard polymer (IV-C) constituting the preferred rubber-containing multistage polymer (IV) is involved in, for example, moldability when molding using the rubber-containing multistage polymer (IV), mechanical properties of the molded product, etc. And an alkyl methacrylate (IV-C1) having an alkyl group having 1 to 4 carbon atoms and another monomer (IV-C2) having a copolymerizable double bond used as necessary. A polymer as a constituent component, which is polymerized at the end of the rubber-containing multistage polymer (IV).

  Preferred specific examples of the components (IV-C1) and (IV-C2) are the same as those mentioned for the components (IV-A1) and (IV-A2) of the first elastic polymer (IV-A), respectively. . The amount of component (IV-C1) used is preferably 51 to 100 parts by mass. The amount of component (IV-C2) used is preferably 0 to 49 parts by mass. The range of these amounts used is based on a total of 100 parts by mass of components (IV-C1) and (IV-C2).

  The Tg of the hard polymer (IV-C) alone is preferably 60 ° C. or higher, and more preferably 80 ° C. or higher. The content of the hard polymer (IV-C) in 100% by mass of the preferred rubber-containing multistage polymer (IV) is preferably 10 to 80% by mass, more preferably 40 to 60% by mass.

  A preferable rubber-containing multistage polymer (IV) has the first elastic layer polymer (IV-A), the second elastic polymer (IV-B) and the hard polymer (IV-C) described above as a basic structure. Have. Then, after the second elastic polymer (IV-B) is polymerized, the intermediate polymer (IV-D) is polymerized before the hard polymer (IV-C) is polymerized.

The intermediate polymer (IV-D) includes an alkyl acrylate (IV-D1) having an alkyl group having 1 to 8 carbon atoms, an alkyl methacrylate (IV-D2) having an alkyl group having 1 to 4 carbon atoms, and Other monomer (IV-D3) having a copolymerizable double bond used as appropriate, polyfunctional monomer (IV-D4) used as required, and graft crossing agent (IV-D5) And the amount of the alkyl acrylate component monotonously decreases from the second elastic polymer (IV-B) toward the hard polymer (IV-C).
Here, monotonically decreasing means that the intermediate polymer (IV-D) has a composition at a certain point between the second elastic polymer (IV-B) and the hard polymer (IV-C). This means that the composition gradually (continuously) approaches the polymer (IV-B) to the hard polymer (IV-C), and the composition approaches stepwise, and in particular, has a composition at one intermediate point. Since the transparency when molding the rubber-containing multistage polymer (IV) is improved, it is preferable.

  Preferred specific examples of the components (IV-D1) to (IV-D5) are the same as those described for the components (IV-A1) to (IV-A4) of the first elastic polymer (IV-A), respectively. . In particular, the graft crossing agent (IV-D5) used for the intermediate polymer (IV-D) is a component necessary for tightly bonding the polymers and obtaining excellent properties.

  As for the usage-amount of a component (IV-D1), 10-90 mass parts is preferable. As for the usage-amount of a component (IV-D2), 10-90 mass parts is preferable. The amount of component (IV-D3) used is preferably 0 to 20 parts by mass. The amount of component (IV-D4) used is preferably 0 to 10 parts by mass. The amount of component (IV-D5) used is preferably 0.1 to 5 parts by mass. The range of these amounts used is based on a total of 100 parts by mass of components (IV-D1) to (IV-D4).

  The content of the intermediate polymer (IV-D) in 100% by mass of the preferred rubber-containing multistage polymer (IV) is preferably 5 to 35% by mass. If the content is 5% by mass or more, it functions well as an intermediate polymer, and if it is 35% by mass or less, the balance of the final polymer is good.

  The average particle size of the rubber-containing multistage polymer (IV) produced by the emulsion polymerization method of the present invention is 0.08 to 0.2 μm in consideration of the mechanical properties and transparency of a molded product containing this as a main component. A range is preferred.

  Further, when the rubber-containing multistage polymer (IV) is dispersed in acetone, the number of particles having a diameter of 55 μm or more present in the dispersion is 0 to 50 per 100 g of the rubber-containing multistage polymer. When the containing multistage polymer (IV) is formed into a film, the appearance tends to be good. When the rubber-containing multistage polymer is dispersed in acetone, the number of particles having a diameter of 55 μm or more present in the dispersion is 0 to 50 per 100 g of the rubber-containing multistage polymer (IV ) By emulsion polymerization is not particularly limited. For example, when the above-mentioned preferable rubber-containing multistage polymer (IV) is produced by emulsion polymerization, the first elastic polymer (IV-A) is particularly preferred. A monomer mixture comprising at least an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and / or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, and a graft crossing agent to give a layer, water and a surfactant After the emulsion prepared by mixing with the polymer was fed to the reactor and polymerized, the second elastic polymer (IV-B), the intermediate polymer (IV-D) and the hard polymer (IV-C) were obtained. Method of polymerizing supplying a monomer or monomer mixture in each reactor in order is preferred.

When the monomer mixture that gives the first elastic polymer (IV-A) is mixed with water and a surfactant, an emulsion prepared by feeding it to the reactor and polymerizing it, particularly when dispersed in acetone In addition, the rubber-containing multistage polymer (IV) in which the number of particles having a diameter of 55 μm or more present in the dispersion is 0 to 50 per 100 g of the rubber-containing multistage polymer can be easily obtained.
The mass ratio of the monomer mixture and water used at that time is preferably 10 parts to 500 parts of water with respect to 100 parts of the monomer mixture, more preferably 100 parts to 300 parts of water with respect to 100 parts of the monomer mixture. Part range.

  As the surfactant used in preparing the emulsion, an anionic, cationic, and nonionic surfactant can be used, and an anionic surfactant is particularly preferable. Examples of anionic surfactants include rosin acid soap, potassium oleate, sodium stearate, sodium myristate, sodium N-lauroylsarcosate, alkenyl succinate dipotassium salt, sulfate ester such as sodium lauryl sulfate, etc. Examples thereof include salts, sulfonic acid salts such as sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium alkyldiphenyl ether disulfonate, and phosphoric acid ester salts such as sodium polyoxyethylene alkylphenyl ether phosphate.

  In addition, as a method for preparing an emulsion, a method of charging a surfactant after charging a monomer mixture in water, a method of charging a monomer mixture after charging a surfactant into water, a monomer Examples thereof include a method in which water is added after charging a surfactant into the mixture. Of these, the method of charging the surfactant after charging the monomer mixture into water and the method of charging the monomer mixture after charging the surfactant into water include the rubber-containing multistage polymer (IV). It is preferable as a method of obtaining.

Moreover, as a mixing device for preparing an emulsion prepared by mixing a monomer mixture that gives the first elastic polymer (IV-A) with water and a surfactant, a stirrer equipped with a stirring blade and Various forced emulsifiers such as homogenizers and homomixers, membrane emulsifiers, and the like can be mentioned.
In addition, as the emulsion to be prepared, any dispersion structure of W / O type and O / W type can be used, but in particular, O / W type in which oil droplets of a monomer mixture are dispersed in water, The diameter of the oil droplets in the dispersed phase is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 15 μm or less. When it exceeds 100 μm, when the obtained rubber-containing multistage polymer (IV) is dispersed in acetone, the number of particles having a diameter of 55 μm or more present in the dispersion tends to increase.

  On the other hand, the first elastic polymer (IV-A), the second elastic polymer (IV-B), the intermediate polymer (IV-D) and the hard polymer (IV) constituting the preferred rubber-containing multistage polymer (IV). As the polymerization initiator used in forming -C), a known one can be used, and the addition method can be a method of adding to one or both of the aqueous phase and the monomer phase. As a particularly preferred example of the initiator, a peroxide, an azo initiator, or a redox initiator combined with an oxidizing agent / reducing agent is used. Among these, a redox initiator is more preferable, and a sulfoxylate initiator combined with ferrous sulfate / ethylenediaminetetraacetic acid disodium salt / longalite / hydroperoxide is particularly preferable.

In particular, a monomer mixture that gives the first elastic polymer (IV-A) described above is mixed with water and a surfactant and polymerized by supplying an emulsion to the reactor, and then the second elastic polymer. In the method in which the monomer or monomer mixture that gives (IV-B), the intermediate polymer (IV-D), and the hard polymer (IV-C) is sequentially fed to the reactor and polymerized, After heating the aqueous solution containing iron, ethylenediaminetetraacetic acid disodium salt and Rongalite to the polymerization temperature, the prepared emulsion is supplied to the reactor for polymerization, and then a second elasticity containing a polymerization initiator such as peroxide. A method in which a monomer mixture giving a polymer (IV-B), an intermediate polymer (IV-D) and a hard polymer (IV-C) is sequentially fed to a reactor and polymerized is preferred. Most preferred as a method for obtaining IV).
The polymerization temperature varies depending on the type and amount of the polymerization initiator used, but is preferably 40 to 120 ° C, and more preferably 60 to 95 ° C.

When the rubber-containing multistage polymers (I), (III), and (IV) are obtained by emulsion polymerization as described above, a chain transfer agent, other polymerization aids, and the like may be used. Known chain transfer agents can be used, and mercaptans are preferred.
The rubber-containing multistage polymer (I), (III), (IV) can be produced by recovering the rubber-containing multistage polymer from the polymer latex produced by the above-described method. The method for recovering the rubber-containing multistage polymer from the polymer latex is not particularly limited, and examples thereof include salting out or acid precipitation coagulation, spray drying, freeze drying and the like. By these methods, the rubber-containing multistage polymers (I), (III) and (IV) are recovered in powder form.
In the powdery rubber-containing multistage polymer (I), (III), (IV) obtained by the above method, a diameter of 55 μm or more present in the dispersion when dispersed in acetone is used. The number of the particles is preferably in the range of 0 to 50 per 100 g of each rubber-containing multistage polymer.

<Manufacture of colored acrylic resin film>
Examples of a method for forming the colored acrylic resin film of the present invention include known solution casting methods, melt extrusion methods such as a T-die method, and an inflation method. Of these, the T-die method is particularly preferable from the viewpoint of economy.
The thickness of the colored acrylic resin film is preferably 10 to 500 μm from the viewpoint of film properties. When the thickness of the colored acrylic resin film is from 10 to 500 μm, the film has an appropriate rigidity, so that the laminating property, the secondary processability, etc. are facilitated, the film forming property is stabilized, and the production of the film is facilitated. The thickness of the colored acrylic resin film is more preferably 15 μm to 200 μm, and further preferably 30 μm to 200 μm.

  For the colored acrylic resin film, if necessary, usual compounding agents such as stabilizers, lubricants, processing aids, plasticizers, impact aids, foaming agents, fillers, antibacterial agents, antifungal agents, foaming Agents, mold release agents, antistatic agents, matting agents, ultraviolet absorbers, and the like may be added. In terms of protecting the substrate (retroreflective sheet), it is particularly preferable to add an ultraviolet absorber in order to impart weather resistance. The molecular weight of the ultraviolet absorber is preferably 300 or more, particularly preferably 400 or more. When an ultraviolet absorber having a molecular weight of less than 300 is used, it may volatilize on a transfer roll or the like when producing a film, thereby causing roll contamination. As the ultraviolet absorber, a benzotriazole-based ultraviolet absorber having a molecular weight of 400 or more or a triazine-based ultraviolet absorber having a molecular weight of 400 or more is particularly preferable. Specific examples of the benzotriazole ultraviolet absorber having a molecular weight of 400 or more include Tinuvin 234 manufactured by Ciba Specialty Chemicals Co., Ltd. and Adeka Stub LA-31 manufactured by Asahi Denka Kogyo Co., Ltd. Specific examples of the triazine-based ultraviolet absorber having a molecular weight of 400 or more include Tinuvin 1577 manufactured by Ciba Specialty Chemicals.

  Examples of the method of adding the compounding agent include a method of supplying the film forming machine for film formation together with the acrylic resin; and a method of kneading and mixing the mixture obtained by adding the compounding agent to the acrylic resin in advance with various kneaders . Examples of the kneader used in the latter method include ordinary single screw extruders, twin screw extruders, Banbury mixers, roll kneaders, and the like.

[Retroreflective sheet]
The retroreflective sheet having the colored acrylic resin film for the skin of the retroreflective sheet according to the present invention on the surface is mainly used for road signs, display boards, or safety devices for the purpose of visibility.
The types of retroreflective sheets include capsule-type retroreflective sheets in which glass beads subjected to aluminum vapor deposition are embedded in the base material, and prism-type retroreflective sheets that use a prism-processed resin sheet as a reflector. The colored acrylic resin film for retroreflective sheeting of the present invention is used as a surface material laminated on the surface of the retroreflective sheet.

For example, a capsule-type retroreflective sheet is manufactured as follows.
The upper half of the glass bead is temporarily embedded in the temporary support layer, and a metal film is deposited on the entire surface across the gap between the lower hemisphere of the bead and the beads, and then a support film made of a thermoplastic resin is applied in close contact therewith. Then, the surface is further covered with a film made of a heat-resistant resin and the like, the temporary support layer on the opposite side is peeled off, and the colored acrylic resin film of the present invention is overlaid on the upper hemisphere portion of the exposed glass beads . Next, this is heated and pressed from the film side made of a heat-resistant resin, etc. by a mold having a convex mesh pattern for making a desired independent small compartment vacant space, and the support film is thermally melted to give a colored acrylic resin film The capsule-type retroreflective sheet is manufactured by forming a connection wall according to the above pattern to form independent small compartment vacancies. At this time, if the adhesion area between the support film and the colored acrylic resin film is large, reflection performance important as a retroreflective sheet tends to be impaired.

Hereinafter, the present invention will be described by way of examples.
Here, “part” in Examples and Comparative Examples represents “part by mass”, and “%” represents “mass%”. Abbreviations in the preparation examples are as follows.
Methyl methacrylate: MMA
Butyl acrylate: BA
Methyl acrylate: MA
Styrene: ST
Allyl methacrylate: AMA
1,3-butylene glycol dimethacrylate: BD
t-Butyl hydroperoxide: tBH
Cumene hydroperoxide: CHP
n-octyl mercaptan: n-OM

In Examples and Comparative Examples, evaluation of the prepared rubber-containing multistage polymer and measurement of various physical properties of the colored acrylic resin film were carried out by the following test methods.
(1) Mass average particle diameter of rubber-containing multistage polymer:
The polymer latex of a rubber-containing multistage polymer obtained by emulsion polymerization was measured and determined by a dynamic light scattering method using a light scattering photometer DLS-700 manufactured by Otsuka Electronics Co., Ltd.
(2) Total light transmittance of colored acrylic resin film:
It measured based on JISK7361-1.
(3) Chromaticity coordinates (x, y) and Y value of the colored acrylic resin film:
The standard color card 230 of NIPPON KENKEN CO., LTD. (Mouse color with Munsell symbol N5.5) and a colored acrylic resin film are overlaid, and the colored acrylic resin film side is the illumination and light receiving geometry specified in JIS Z8722. The measurement was performed under the condition of standard light D65 under the general condition a (45 ° illumination, vertical light reception).
(4) Chromaticity coordinates (x, y) and Y value of the colored acrylic resin film on the white reflective sheet:
A colored acrylic resin film is placed on a commercially available capsule lens type retroreflective sheet (white) (trade name: Nikkalite ULS, manufactured by Nikka Polymer Co., Ltd.), and the colored acrylic resin film side is illuminated and received according to JIS Z8722. The measurement was performed under the condition of standard light D65 under the geometric condition a (45 ° illumination, vertical light reception).
(5) Visibility:
A commercially available capsule lens type retroreflective sheet (white) (made by Nikka Polymer Co., Ltd., trade name: Nikkalite ULS) is pasted with a colored acrylic resin film, and a donut-shaped retroreflective sheet having an outer diameter of 10 cm and a width of 2 cm is cut out from this. It was. The cut-out retroreflective sheet is affixed to a 20cm x 20cm white blank paper, installed perpendicular to the ground, the car is stopped at a distance of about 50m from the retroreflective sheet, and the retroreflective sheet is observed from the driver's seat. did. In addition, the headlight of the motor vehicle was used as light which illuminates the cut out donut-shaped retroreflection sheet.
○: The cut out donut-shaped circle can be clearly confirmed.
X: The cut-out donut-shaped circle cannot be confirmed clearly.
(6) Weather resistance:
A colored acrylic resin film is heat-laminated at 140 ° C. on an acrylic plate having a thickness of 3 mm, and the colored acrylic resin film side of the sample is used with a sunshine weatherometer (manufactured by Suga Test Instruments Co., Ltd.). [Raining cycle: 18 minutes (rainfall) / 102 minutes (no rain)], the accelerated exposure test was conducted for 2200 hours under conditions of a temperature of 63 ° C. and an irradiance of 300 to 700 nm of 255 W / m ^2. The subsequent change in hue was visually evaluated, and ○ was given when almost no color change was observed, and x was given when the color change was significant.
(7) Haze Measured according to JIS K7136.

(Preparation Example 1)
Preparation of rubber-containing multistage polymer (I):
195 parts of ion-exchanged water was put in a polymerization vessel equipped with a condenser, and the temperature was raised to 70 ° C., and further, 0.10 parts of sodium formaldehyde sulfoxylate and 0.0002 part of ferrous sulfate were added to 5 parts of ion-exchanged water. The mixture prepared by adding 0.0006 parts of EDTA was added all at once. Next, while stirring under nitrogen, the first monomer mixture and emulsifier (Toho Chemical Co., Ltd.) consisting of 2.3 parts of MMA, 2.13 parts of BA, 0.37 part of ST, 0.2 part of BD and 0.01 part of CHP. ): Phosphanol RS610NA) A mixture of 1.3 parts was dropped into the polymerization vessel over 8 minutes, and then the reaction was continued for 15 minutes to obtain an elastic polymer (IA). Here, Tg of the elastic polymer (IA) was 13 ° C.
Subsequently, after adding a second monomer mixture consisting of 24.54 parts of BA, 4.26 parts of ST, 1.2 parts of BD, 0.225 parts of AMA and 0.03 parts of CHP to the polymerization vessel over 90 minutes, The reaction was continued for 60 minutes to obtain a first intermediate polymer (IB) containing a crosslinked elastic polymer. Here, Tg of the first intermediate polymer (IB) was −40 ° C.
Subsequently, after a third monomer mixture consisting of 6 parts of MMA, 3.28 parts of BA, 0.72 parts of ST, 0.15 part of AMA, and 0.02 part of CHP was dropped into the polymerization vessel over 30 minutes, The reaction was continued for a minute to form a second intermediate polymer (IC). At this time, the latex particle diameter was 0.06 μm.
Next, a fourth monomer mixture consisting of 52.25 parts of MMA, 2.26 parts of BA, 0.49 parts of ST, 0.193 parts of n-OM and 0.055 parts of t-BH was placed in the polymerization vessel over 130 minutes. After the dropping, the reaction was continued for 60 minutes to form a hard polymer (ID), and a polymer latex containing a rubber-containing multistage polymer (I) was obtained. Here, Tg of the hard polymer (ID) was 94 ° C. The mass average particle diameter measured after polymerization was 0.09 μm.
The polymer latex of the obtained rubber-containing multistage polymer (I-1) is filtered using a vibration type filtration device in which a SUS mesh (average opening 62 μm) is attached to the filter medium, and then contains 3 parts of calcium acetate. Salting out was carried out in an aqueous solution, and after washing with water and drying, a powdery rubber-containing multistage polymer (I) was obtained.

(Preparation Example 2)
Preparation of rubber-containing multistage polymer (III):
After charging 10.8 parts of deionized water into a vessel equipped with a stirrer, it consists of MMA 0.3 parts, n-BA 4.45 parts, 1,3-BD 0.2 parts, AMA 0.05 parts, CHP 0.025 parts. The monomer mixture was added and stirred and mixed at room temperature. Next, 1.3 parts of an emulsifier (Toho Chemical Industry Co., Ltd .: Phosphanol RS610NA) was added to the vessel while stirring, and stirring was continued again for 20 minutes to prepare an emulsion.
Next, 139.2 parts of deionized water was put into a polymerization vessel equipped with a condenser, the temperature was raised to 75 ° C., and 0.20 part of sodium formaldehyde sulfoxylate was added to 5 parts of ion-exchanged water. A mixture prepared by adding 0.0001 part of iron and 0.0003 part of EDTA was charged all at once into the polymerization vessel. Next, the emulsion was dropped into the polymerization vessel over 8 minutes while stirring under nitrogen, and then the reaction was continued for 15 minutes to complete the polymerization to obtain an inner layer (III-A-1) of an elastic polymer. It was. Subsequently, a monomer mixture consisting of 9.5 parts of MMA, 14.25 parts of n-BA, 1.0 part of BD, and 0.25 part of AMA was dropped into the polymerization vessel over 90 minutes together with 0.016 part of CHP, and then reacted for 60 minutes. Then, a cross-linked elastic polymer (III-A-2), which is an outer layer of the elastic polymer, was formed to obtain an elastic polymer (cross-linked rubber elastic body) (III-A). Here, the Tg of the inner layer (III-A-1) alone was −48 ° C., and the Tg of the outer layer (III-A-2) alone was −10 ° C.
Subsequently, a monomer mixture consisting of 5.96 parts of MMA, 3.97 parts of MA and 0.07 part of AMA was added dropwise to the polymerization vessel over 45 minutes together with 0.0125 part of CHP, and then the reaction was continued for 60 minutes to obtain an intermediate polymer. (III-B) was formed. Here, the Tg of the intermediate polymer (III-B) alone was 60 ° C.
Next, a monomer mixture consisting of 57 parts of MMA, 3 parts of MA, 0.264 part of n-OM and 0.075 part of t-BH was dropped into the polymerization vessel over 140 minutes, and then the reaction was continued for 60 minutes to obtain a hard polymer ( III-C) was formed, and a polymer latex of a rubber-containing multistage polymer (III) was obtained. Here, the Tg of the hard polymer (III-C) alone was 99 ° C. The mass average particle diameter measured after polymerization was 0.11 μm.
The polymer latex of the obtained rubber-containing multistage polymer (III) is filtered by the same method as in Preparation Example 1, salted out in an aqueous solution containing 3.5 parts of calcium acetate, washed with water, collected and dried. A powdery rubber-containing multistage polymer (III) was obtained.

(Preparation Example 3)
Preparation of rubber-containing multistage polymer (IV):
After charging 10.8 parts of deionized water into a container equipped with a stirrer, it consists of MMA 0.3 part, n-BA 4.5 part, 1,3-BD 0.2 part, AMA 0.05 part, CHP 0.025 part. The monomer mixture was added and stirred and mixed at room temperature. Subsequently, 1.1 parts of an emulsifier (Toho Chemical Industries, Ltd .: Phosphanol RS610NA) was added to the vessel while stirring, and stirring was continued again for 20 minutes to prepare an emulsion.
Next, 139.2 parts of deionized water was put into a polymerization vessel equipped with a condenser, the temperature was raised to 75 ° C., and 0.20 part of sodium formaldehyde sulfoxylate was added to 5 parts of ion-exchanged water. A mixture prepared by adding 0.0001 part of iron and 0.0003 part of EDTA was charged all at once into the polymerization vessel. Next, the emulsion was dropped into the polymerization vessel over 8 minutes while stirring under nitrogen, and then the reaction was continued for 15 minutes to complete the polymerization to obtain the first elastic polymer (IV-A). Subsequently, a monomer mixture composed of 1.5 parts of MMA, 22.5 parts of n-BA, 1.0 part of BD, and 0.25 part of AMA was dropped into the polymerization vessel over 90 minutes together with 0.016 part of CHP, and then reacted for 60 minutes. Was continued to form a second elastic polymer (IV-B) to obtain a two-stage crosslinked rubber elastic body. Here, the Tg of the first elastic polymer (IV-A) alone and the Tg of the second elastic polymer (IV-B) alone were both −48 ° C.
Subsequently, a monomer mixture consisting of 6.0 parts of MMA, 4.0 parts of BA, and 0.075 part of AMA was dropped into the polymerization vessel over 45 minutes together with 0.0125 part of CHP, and then the reaction was continued for 60 minutes to obtain an intermediate polymer. (IV-D) was formed. Here, the Tg of the intermediate polymer (IV-D) alone was 20 ° C.
Subsequently, a monomer mixture consisting of 55.2 parts of MMA, 4.8 parts of BA, 0.192 parts of n-OM and 0.075 parts of t-BH was dropped into the polymerization vessel over 140 minutes, and then the reaction was continued for 60 minutes. A hard polymer (IV-C) was formed to obtain a polymer latex of a rubber-containing multistage polymer (IV). Here, Tg of the rigid polymer (IV-C) alone was 84 ° C. The mass average particle diameter measured after polymerization was 0.12 μm.
The obtained rubber-containing multistage polymer (IV) polymer latex is filtered in the same manner as in Preparation Example 1, and then salted out in an aqueous solution containing 3.5 parts of calcium acetate. A powdery rubber-containing multistage polymer (IV) was obtained.

[Examples 1 to 6, Comparative Examples 4 and 5]
Rubber-containing multistage polymer (I) obtained in Preparation Example 1, rubber-containing multistage polymer (III) obtained in Preparation Example 2, rubber-containing multistage polymer (IV) obtained in Preparation Example 3, thermoplasticity Polymer (II-1), thermoplastic polymer (II-2), LA-31RG (trade name) manufactured by ADEKA as an ultraviolet absorber, and LA-57 (trade name) manufactured by ADEKA as a light stabilizer ), Irganox 1076 (trade name) manufactured by Ciba Specialty Chemicals Co., Ltd. as an antioxidant, pigments and dyes were mixed at a blending amount (mass ratio) shown in the table using a Henschel mixer, and the mixture was mixed at 230 ° C. Was supplied to a deaeration type extruder (PCM-30 manufactured by Ikekai Tekko Co., Ltd.) heated and kneaded to obtain pellets.

Here, as the thermoplastic polymer (II-1), Dianal BR-75 (manufactured by Mitsubishi Rayon Co., Ltd., reduced viscosity 0.057 l / g) is used, and as the thermoplastic polymer (II-2), Dianal BR-80 (manufactured by Mitsubishi Rayon Co., Ltd., reduced viscosity 0.059 l / g) was used.
As pigments and dyes, “Daimic Seika Kogyo Co., Ltd., trade name Dimic Color MBR 151” containing 50% by mass of anthraquinone red pigment (CI Pigment Red 177), anthraquinone yellow dye (CI Solvent) “Daiichi Seika Kogyo Co., Ltd., trade name Dymic Color MBR D-05” containing 91% by mass of Yellow 163), “Dainsei Co., Ltd.” containing 50% by mass of anthraquinone yellow pigment (CI Pigment Yellow 199) "Product name: Dimic Color MBR 421" manufactured by Chemical Industries, Ltd., "Product name: Dimic Color MBR 155, manufactured by Dainichi Seika Kogyo Co., Ltd." containing 50% by mass of perylene red pigment (CI Pigment Red 149). 91 grades of anthraquinone red dye (CI Disperse Red 22) “Daimic Seisaku Kogyo Co., Ltd., trade name Dymic Color MBR D-09” was used.

The pellets produced by the above method were dried overnight at 80 ° C., and a cylinder temperature of 200 ° C. to 240 ° C. was measured using a 40 mmφ non-vented screw type extruder (L / D = 26) equipped with a 300 mm wide T die. A colored acrylic resin film having a thickness of 75 μm was formed at a die temperature of 250 ° C. and a cooling roll temperature of 80 ° C.
The chromaticity coordinates (x, y) in the XYZ color system of the colored acrylic resin film obtained are shown in FIGS. 2 to 3, and the Y value, the total light transmittance measurement results, the visibility, the weather resistance evaluation results, etc. Shown in the table.

[Examples 7 to 9, Comparative Examples 1 to 3]
A colored acrylic resin film having a thickness of 75 μm was obtained in the same manner as in Example 1 except that Tinuvin 1577 manufactured by Ciba Specialty Chemicals Co., Ltd. was used as the ultraviolet absorber.
The chromaticity coordinates (x, y) in the XYZ color system of the colored acrylic resin film obtained are shown in FIGS. 2 to 3, and the Y value, the total light transmittance measurement results, the visibility, the weather resistance evaluation results, etc. Shown in the table.

  The blending amounts of pigments and dyes described in each table are blending amounts as products. That is, for example, in Example 1, “1.5 parts by mass” is described for “MBR 151”, which means that “0.75 parts by mass” is blended as the net pigment amount. To do.

From the examples and comparative examples, the following became clear.
It was shown that when the colored acrylic resin films in Examples 1 to 9 were used, a retroreflective sheet satisfying DIN standards, good visibility and weather resistance, and high industrial utility value could be provided.

On the other hand, when the colored acrylic resin films of Comparative Examples 1, 2, and 5 are used, the obtained retroreflective sheet has good weather resistance but has low transparency and poor visibility. When an acrylic resin film was used, the obtained retroreflective sheet had poor visibility but good weather resistance.
Therefore, since the retroreflective sheet using the colored acrylic resin films of these comparative examples 1 to 5 cannot obtain the hue, high visibility, and weather resistance required as a retroreflective sheet, industrial utility value is obtained. It was shown to be low.

  By using the colored acrylic resin film for the skin of the retroreflective sheet according to the present invention, it is possible to provide a retroreflective sheet that has weather resistance and visibility, and also satisfies transparency and hue. Such a retroreflective sheet can be used for various displays such as road signs and construction signs, and has an extremely high industrial utility value.

It is a graph which shows the range of the chromaticity coordinate (x, y) in the XYZ color system which the colored acrylic resin film for retroreflective sheeting of this invention satisfies. It is a graph which shows the chromaticity coordinate (x, y) in the XYZ color system of the colored acrylic resin film of an Example and a comparative example. It is the graph which expanded FIG.

Claims (3)

A colored acrylic resin film used as a skin material for a retroreflective sheet, containing an acrylic resin, an anthraquinone red pigment and an anthraquinone yellow dye,
The anthraquinone red pigment is blended in an amount of 0.5 to 1 part by mass based on 100 parts by mass of the acrylic resin, and the mass ratio of the anthraquinone red pigment to the anthraquinone yellow dye (anthraquinone red pigment / anthra Quinone yellow dye) is 1/5 to 10/1,
A colored acrylic resin film for a retroreflective sheeting having a total light transmittance of 17% or more as measured by a method defined in JIS K7361-1.  The colored acrylic resin film for retroreflective sheeting according to claim 1, further comprising an anthraquinone yellow pigment.  The colored acrylic resin film for the retroreflective sheet skin according to claim 1 or 2 and the murine colored oily colored paper having a Munsell symbol of N5.5 are overlapped, and the colored acrylic resin film side for the retroreflective sheet skin is attached to JIS Z8722. Retroreflective sheet skin characterized in that the Y value measured in the standard light D65 condition is in the range of 2 to 12 according to the specified illumination and reception geometric condition a (45 ° illumination, vertical light reception) Colored acrylic resin film.

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