JP2012171972A - Acrylic resin film, method of manufacturing the same, and retroreflection sheet using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic resin film which has excellent blocking property, even when made into a roll-formed article obtained by winding up the acrylic resin film, has excellent releasability at high temperature from the mold having a fine structure, and to provide a method of manufacturing the acrylic resin film and a retroreflection sheet using the acrylic resin film.SOLUTION: The acrylic resin film is obtained from an acrylic resin composition (C) containing 100 pts.mass of an acrylic resin (A) and 0.1 to 3.8 pts.mass of a surfactant (B), in which a heat distortion temperature (HDT) is 80 to 130°C, when the heat deformation amount of a test piece is 0.25 mm after measuring the HDT under a specified condition according to ASTM D648. There are provided the method of manufacturing the acrylic resin film having a fine structure on its surface, which is obtained by releasing it from the mold after thermal pressing of the mold having the fine structure on its surface onto the surface of the acrylic resin film, and the retroreflection sheet using the acrylic resin film having the fine structure on the surface.

Description

  The present invention relates to an acrylic resin film, a method for producing an acrylic resin film, and a retroreflective sheet using the same.

  Retroreflective sheets that reflect incident light in 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 in dark places.

  For example, a sign such as a road sign or a construction sign using a retroreflective sheet reflects light from a light source of a headlight of a vehicle traveling in a dark place such as at night toward the light source, that is, the direction of the traveling vehicle. It has excellent characteristics of providing excellent visibility to a vehicle driver who is a viewer of a sign and enabling clear information transmission.

  By using an acrylic film as a skin material as a retroreflective sheet used as a sign such as a road sign or a construction sign, excellent characteristics such as weather resistance and visibility can be imparted.

As a retroreflective sheet used for the above-mentioned applications, the use of a retroreflective sheet using a prism is expanding due to its excellent retroreflective performance. (For example, Patent Document 1 and Patent Document 2)
As one of the methods for producing the prism type retroreflective sheet, there is a method in which the prism shape on the surface of the prism type retroreflective sheet is formed by a thermal transfer method using a mold having a prism shape.

  However, in the above method, in order to produce an acrylic resin film having a good prism shape under high production conditions such as continuous production, releasability may be a problem when transferring and peeling continuously. is there.

As one of the methods for solving the above problem, it is conceivable to use an acrylic resin film having improved releasability. (For example, Patent Document 3)
However, the use of the acrylic resin film improves the mold releasability. However, when the acrylic resin film is wound up, the acrylic resin films are easily attached to each other, and the acrylic resin film is unwound from the roll-shaped article. There is a problem of blocking property that cannot be performed.

Japanese Patent Laid-Open No. 10-105,091 JP 2001-264525 A JP 2003-238,704 A

  The subject of the present invention is that even if it is a roll-shaped article obtained by winding an acrylic resin film, the blocking property is good, and the releasability at a high temperature from a mold having a fine structure is excellent. An acrylic resin film, a method for producing the same, and a retroreflective sheet using the same.

The gist of the present invention is that HDT when the amount of thermal deformation of the test piece after measuring the thermal deformation temperature (HDT) under the following conditions according to ASTM D648 is 0.25 mm (hereinafter referred to as “present HDT”). Resin composition containing 100 parts by mass of acrylic resin (A) having a temperature of 80 to 130 ° C. and 0.1 to 3.8 parts by mass of surfactant (B) (relative to 100 parts by mass of acrylic resin (A)) An acrylic resin film obtained from the product (C) (hereinafter referred to as “the present acrylic resin film”) is the first invention.
<HDT measurement conditions>
Test piece: 127 mm in length, 6.4 mm in width and 12.7 mm in height
Span length by Method A: 101.3mm
Load: 0.45 MPa
Temperature rise rate: 2 ° C / min load test piece part: edgewise Further, the gist of the present invention is that the mold having a microstructure on the surface of the acrylic resin film is hot-pressed and then the mold is used. The manufacturing method of this acrylic resin film which peels this acrylic resin film and has the fine structure on the surface is made into 2nd invention.

  Furthermore, the gist of the present invention is a retroreflective sheet using the present acrylic resin film having a fine structure on the surface as a third invention.

  According to the present invention, even in the case of a roll-shaped article obtained by winding up the acrylic resin film, the blocking property is good, and the release property at a high temperature from the mold having a fine structure is excellent. Since this acrylic resin film having a fine structure is obtained under high production conditions, it is suitable for optical member applications such as retroreflective sheets.

Acrylic resin (A)

The HDT of the acrylic resin (A) used in the present invention is 80 to 130 ° C.

  In a roll-shaped article (hereinafter referred to as “this roll-shaped article”) in which the present HDT is 80 ° C. or more and the acrylic resin film is wound up, it is possible to suppress adhesion between the acrylic resin films. The blocking property of the roll-shaped article is good. In addition, the HDT is 130 ° C. or lower, and it is possible to reduce the heating temperature when transferring the fine structure to the surface of the acrylic resin film by the thermal transfer method, and the process passability is good even under high production conditions. Can be economically advantageous.

  As the acrylic resin (A), for example, an alkyl acrylate having at least one selected from methyl methacrylate, ethyl methacrylate, propyl methacrylate and n-butyl methacrylate as a main raw material and having an alkyl group having 1 to 8 carbon atoms as necessary And a single polymer or copolymer obtained from a monomer raw material having other copolymerizable monomers such as vinyl acetate, vinyl chloride, styrene, acrylonitrile, methacrylonitrile and the like.

  In addition to the above, the acrylic resin (A) is disclosed in JP-A 52-56,150, JP-A 57-140,161, JP-A 58-215,444 and JP-A 63-. The polymer described in 77,963 gazette can be used.

  In the present invention, examples of the acrylic resin (A) include those containing an acrylic polymer having a multilayer structure shown below (hereinafter referred to as “multilayer structure polymer (1)”).

  In the present invention, the acrylic resin (A) includes a multilayer polymer (1) and a polymer having the following alkyl methacrylate units as main components (hereinafter referred to as “thermoplastic polymer (2)”). What is contained is preferable in that the heat resistance and flexibility of the acrylic resin film can be easily adjusted by changing the ratio between the multilayer structure polymer (1) and the thermoplastic polymer (2).

  As a compounding quantity of a multilayer structure polymer (1), with respect to the softness | flexibility and heat resistance of this acrylic resin film, with respect to 100 mass parts of total amounts of a multilayer structure polymer (1) and a thermoplastic polymer (2). 1-99 mass parts is preferable, 50-95 mass parts is more preferable, 70-95 mass parts is still more preferable.

Moreover, as a compounding quantity of a thermoplastic polymer (2), 1-99 mass parts is preferable with respect to 100 mass parts of total amounts of a multilayer structure polymer (1) and a thermoplastic polymer (2). When the blending amount of the thermoplastic polymer (2) is 99 parts by mass or less, preferably 50 parts by mass or less, more preferably 30 parts by mass or less, the acrylic resin film tends to be flexible. Moreover, the blending amount of the thermoplastic polymer (2) is 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and the heat resistance of the acrylic resin film tends to be good. is there.

<Multilayer structure polymer (1)>

Examples of the multilayer structure polymer (1) used in the present invention include the innermost layer polymer (1-A), the intermediate layer polymer (1-B), and the outermost layer polymer (1-C) shown below. ) Having a multilayer structure.

  In the present invention, the multilayer structure polymer having the innermost layer polymer (1-A), the intermediate layer polymer (1-B) and the outermost layer polymer (1-C) is first the innermost layer polymer (1 -A), and then the intermediate layer polymer (1-B) is prepared in the presence of the innermost layer polymer (1-A), and further in the presence of the intermediate layer polymer (1-B). A polymer obtained by producing the outer layer polymer (1-C). Further, in the following, a multilayer having two or more layers refers to a multistage polymer having two or more stages obtained by polymerization in the presence.

Moreover, as a manufacturing method of a multilayer structure polymer (1), the manufacturing method of the multilayer structure polymer (1) shown below is mentioned.

<Innermost layer polymer (1-A)>

The innermost layer polymer (1-A) used in the present invention is for constituting the central portion of the multilayer structure polymer (1).

  The content of the innermost layer polymer (1-A) in the multilayer structure polymer (1) can be any content.

  The innermost layer polymer (1-A) may be a single layer or a multilayer. When the innermost layer polymer (1-A) has two layers, the monomer composition of each layer may be the same or different.

When the innermost layer polymer (1-A) has two layers, the glass transition temperature (Tg) of the inner layer (1-A ₁ ) and the Tg of the outer layer (1-A ₂ ) may be the same or different. .

  Examples of the innermost layer polymer (1-A) include alkyl acrylate (1-A1), alkyl methacrylate (1-A2), and other monomers having a double bond copolymerizable therewith (1 -A3), the polymer obtained by superposing | polymerizing the monomer component which uses a polyfunctional monomer (1-A4) and a graft crossing agent (1-A5) as a structural component is mentioned.

  As the Tg of the innermost layer polymer (1-A), when the intermediate layer polymer (1-B) described later is included, the intermediate layer polymer (1- Preferably it is lower than the Tg of B).

  The Tg of the innermost layer polymer (1-A) is preferably less than 25 ° C., more preferably 10 ° C. or less, and still more preferably 0 ° C. or less in view of the flexibility of the multilayer structure polymer (1).

  In the present invention, Tg is a value calculated from the FOX equation using the values described in Polymer Handbook (Polymer Handbook (J. Brandrup, Interscience, 1989)).

  In the above monomer component, the alkyl acrylate (1-A1) and the graft crossing agent (1-A5) are essential components, and the alkyl methacrylate (1-A2) and other single units having a double bond. The monomer (1-A3) and the polyfunctional monomer (1-A4) are optional components.

  Examples of the alkyl acrylate (1-A1) include those in which the alkyl group is linear or branched.

  Specific examples of the alkyl acrylate (1-A1) include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and n-octyl acrylate. These can be used alone or in admixture of two or more.

  Examples of the alkyl methacrylate (1-A2) include those in which the alkyl group is linear or branched.

  Specific examples of the alkyl methacrylate (1-A2) include methyl methacrylate, ethyl methacrylate, propyl methacrylate and n-butyl methacrylate. These can be used alone or in admixture of two or more.

  Examples of the other monomer (1-A3) having a double bond include acrylic monomers such as lower alkoxy acrylate, cyanoethyl acrylate, acrylamide, acrylic acid, and methacrylic acid; and aromatics such as styrene and alkyl-substituted styrene. And vinyl cyanide monomers such as acrylonitrile and methacrylonitrile. These can be used alone or in admixture of two or more.

  Examples of the polyfunctional monomer (1-A4) include a crosslinkable monomer having two or more copolymerizable double bonds in one molecule.

  Specific examples of the polyfunctional monomer (1-A4) include ethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butylene glycol di (meth) acrylate, propylene Examples include alkylene glycol di (meth) acrylates such as glycol di (meth) acrylate; polyvinylbenzenes such as divinylbenzene and trivinylbenzene; and cyanurate monomers such as triallyl cyanurate and triallyl isocyanurate. These can be used alone or in admixture of two or more.

  In the present invention, “(meth) acrylate” means “acrylate” or “methacrylate”.

  In the present invention, the monomer component for obtaining the innermost layer polymer (1-A) is at least selected from the polyfunctional monomer (1-A4) and the graft crossing agent (1-A5) described later. One kind can be contained.

  Examples of the graft crossing agent (1-A5) include monomers having two or more different copolymerizable double bonds in one molecule.

  Specific examples of the graft crossing agent (1-A5) include allyl, methallyl, or crotyl esters of copolymerizable α, β-unsaturated carboxylic acid or dicarboxylic acid. These can be used alone or in admixture of two or more.

  In the present invention, cyanurate monomers such as triallyl cyanurate and triallyl isocyanurate used as the polyfunctional monomer (1-A4) are used as the graft crossing agent (1-A5). be able to.

  In the polymerization of the monomer containing the graft crossing agent (1-A5), the conjugated unsaturated bond constituting the ester in the graft crossing agent (1-A5) is an allyl group, a methallyl group or a crotyl group. The polymerization takes place with a much faster reaction. Accordingly, a significant portion of the allyl group, methallyl group or crotyl group in the graft crossing agent (1-A5) after polymerization remains unreacted, and when the intermediate layer polymer (1-B) of the next layer is obtained. It is used to effectively polymerize and to provide a graft bond between adjacent two layers.

  In the present invention, a chain transfer agent can be contained in the monomer component for obtaining the innermost layer polymer (1-A).

As said chain transfer agent, a C2-C20 alkyl mercaptan, mercapto acids, thiophenol, and carbon tetrachloride are mentioned, for example. These can be used individually or in mixture of 2 or more types.

The total amount of alkyl acrylate (1-A1) and alkyl methacrylate (1-A2) in the monomer component for obtaining the innermost layer polymer (1-A) is 80 to 99.9% by mass. It is done.

  Examples of the content of the alkyl acrylate (1-A1) in the monomer component for obtaining the innermost layer polymer (1-A) include 50 to 99.9% by mass.

  Examples of the content of alkyl methacrylate (1-A2) in the monomer component for obtaining the innermost layer polymer (1-A) include 0 to 49.9% by mass.

  The content of the other monomer (1-A3) having a copolymerizable double bond in the monomer component for obtaining the innermost layer polymer (1-A) is 0 to 20% by mass. It is done.

  0-10 mass% is mentioned as content of the polyfunctional monomer (1-A4) in the monomer component for obtaining an innermost layer polymer (1-A).

The content of the graft crossing agent (1-A5) in the monomer component for obtaining the innermost layer polymer (1-A) is 0.1 to 10% by mass.


<Intermediate layer polymer (1-B)>

Examples of the intermediate layer polymer (1-B) include alkyl acrylate (1-B1), alkyl methacrylate (1-B2), and other monomers having a double bond copolymerizable with these (1-B3). ), A polymer obtained by graft polymerization of a monomer component having a polyfunctional monomer (1-B4) and a graft crossing agent (1-B5) as constituent components.

  The intermediate layer polymer (1-B) is obtained by polymerizing the above monomer components in the presence of the innermost layer polymer (1-A).

  The content of the intermediate layer polymer (1-B) when the intermediate layer polymer (1-B) is present in the multilayer structure polymer (1) is 5 to 35% by mass, preferably 5 to 20% by mass. preferable. Within this range, the content of the intermediate layer polymer (1-B) tends to be compatible with molding whitening resistance, heat resistance and flexibility of the acrylic resin film, and an acrylic resin composition described later. It exists in the tendency which can make favorable film forming property when shape | molding a thing (C) in a film form.

  The Tg of the intermediate layer polymer (1-B) is preferably higher than the Tg of the innermost layer polymer in terms of the resistance to molding whitening of the acrylic resin film.

  In the above monomer components, alkyl acrylate (1-B1), alkyl methacrylate (1-B2), and graft crossing agent (1-B5) are essential components, and other single components having a double bond. The monomer (1-B3) and the polyfunctional monomer (1-B4) are optional components.

  Examples of the alkyl acrylate (1-B1) include those in which the alkyl group is linear or branched.

  Specific examples of alkyl acrylate (1-B1) include the same monomers as alkyl acrylate (1-A1). These can be used alone or in admixture of two or more.

  Examples of the alkyl methacrylate (1-B2) include those in which the alkyl group is linear or branched.

Specific examples of alkyl methacrylate (1-B2) include the same monomers as alkyl methacrylate (1-A2). These can be used alone or in admixture of two or more.

Examples of the other monomer (1-B3) having a double bond include the same monomers as the other monomer (1-A3) having a double bond. These can be used alone or in admixture of two or more.

  Examples of the polyfunctional monomer (1-B4) include the same monomers as the polyfunctional monomer (1-A4). These can be used alone or in admixture of two or more. These can be used alone or in admixture of two or more.

  In the present invention, the monomer component for obtaining the intermediate layer polymer (1-B) is at least selected from the polyfunctional monomer (1-B4) and the graft crossing agent (1-B5) described later. By including one kind, for example, even when heat resistance or the like is strictly required for the acrylic resin (A), a stable intermediate layer polymer (1-B) tends to be obtained.

  Examples of the graft crossing agent (1-B5) include the same monomers as the graft crossing agent (1-A5). These can be used alone or in admixture of two or more.

  In the present invention, cyanurate monomers such as triallyl cyanurate and triallyl isocyanurate used as the polyfunctional monomer (1-B4) are used as the graft crossing agent (1-B5). be able to.

  In the polymerization of the monomer containing the graft crossing agent (1-B5), the conjugated unsaturated bond constituting the ester in the graft crossing agent (1-B5) is an allyl group, methallyl group or crotyl group. The polymerization takes place with a much faster reaction. Accordingly, a significant portion of the allyl group, methallyl group or crotyl group in the graft crossing agent (1-A5) after polymerization remains unreacted, and when the intermediate layer polymer (1-B) of the next layer is obtained. It is used to effectively polymerize and to provide a graft bond between adjacent two layers.

  In the present invention, a chain transfer agent can be contained in the monomer component for obtaining the intermediate layer polymer (1-B).

As said chain transfer agent, the chain transfer agent similar to the chain transfer agent used in order to obtain innermost layer polymer (1-A) is mentioned, It can use individually or in mixture of 2 or more types.

The total amount of alkyl acrylate (1-B1) and alkyl methacrylate (1-B2) in the monomer component for obtaining the intermediate layer polymer (1-B) is 19.8 to 99.9% by mass. Is mentioned.

  9.9-90 mass% is mentioned as content of the alkyl acrylate (1-B1) in the monomer component for obtaining an intermediate | middle layer polymer (1-B).

  9.9-90 mass% is mentioned as content of the alkyl methacrylate (1-B2) in the monomer component for obtaining an intermediate | middle layer polymer (1-B).

  The content of the other monomer (1-B3) having a copolymerizable double bond in the monomer component for obtaining the intermediate layer polymer (1-B) is 0 to 20% by mass. It is done.

  0-10 mass% is mentioned as content of the polyfunctional monomer (1-B4) in the monomer component for obtaining an intermediate | middle layer polymer (1-B).

0.1-10 mass% is mentioned as content of the graft crossing agent (1-B5) in the monomer component for obtaining an intermediate | middle layer polymer (1-B).

In the present invention, the composition of the intermediate layer polymer (1-B) is preferably different from the composition of the innermost layer polymer (1-A). By differentiating the compositions of the innermost layer polymer (1-A) and the intermediate layer polymer (1-B), the whitening resistance of the acrylic resin film tends to be improved.

  The “different composition” as used in the present invention refers to those in which at least one of the types and amounts of monomers forming each polymer is different.

In the present invention, the Tg of the intermediate layer polymer (1-B) alone is preferably 25 to 100 ° C. When the Tg of the intermediate layer polymer (1-B) alone is 25 ° C. or higher, preferably 40 ° C. or higher, more preferably 50 ° C. or higher, the heat resistance and flexibility of the acrylic resin (A) tend to be good. Further, the Tg of the intermediate layer polymer (1-B) alone is 100 ° C. or less, preferably 80 ° C. or less, more preferably 70 ° C. or less, and the film forming property when the acrylic resin (A) is formed into a film is obtained. It tends to be good, and the acrylic resin film tends to have good molding whitening resistance.

<Outermost layer polymer (1-C)>

As the outermost layer polymer (1-C), alkyl methacrylate (1-C1), alkyl acrylate (1-C2) and other monomers having a double bond copolymerizable therewith (1-C3) ) Is a polymer obtained by polymerizing a monomer component.

  The outermost layer polymer (1-C) is prepared in the presence of the intermediate layer polymer (1-B) obtained by polymerization in the presence of the innermost layer polymer (1-A) or the innermost layer polymer (1- It can be obtained by graft polymerization of the above monomer components in the presence of A).

  The Tg of the outermost layer polymer (1-C) is preferably 60 ° C. or higher. When the Tg of the outermost layer polymer (1-C) is 60 ° C. or higher, preferably 80 ° C. or higher, more preferably 90 ° C. or higher, the acrylic resin film having good heat resistance tends to be obtained. Further, the Tg of the outermost layer polymer (1-C) is 105 in terms of the solidification property of the multilayer structure polymer (1) and the handleability of the multilayer structure polymer (1) when obtained by emulsion polymerization. C. or lower is preferable.

  The outermost polymer (1-C) can be a single layer or a multilayer of two or more layers depending on the purpose. When the outermost layer polymer (1-C) having two or more layers is used, the outermost layer polymer is obtained by polymerizing the monomer component for obtaining the outermost layer polymer (1-C) in two or more stages. (1-C) can be obtained.

  As content of outermost layer polymer (1-C) in a multilayer structure polymer (1), 10-80 mass% is mentioned.

  In the monomer component for obtaining the outermost layer polymer (1-C), alkyl methacrylate (1-C1) is an essential component, and alkyl acrylate (1-C2) and a double copolymerizable therewith The other monomer (1-C3) having a bond is an optional component.

  Examples of the alkyl methacrylate (1-C1) include those in which the alkyl group is linear or branched.

  Specific examples of alkyl methacrylate (1-C1) include the same monomers as alkyl methacrylate (1-A2). These can be used alone or in admixture of two or more.

  Examples of alkyl acrylate (1-C2) include those in which the alkyl group is linear or branched.

  Specific examples of alkyl acrylate (1-C2) include the same monomers as alkyl acrylate (1-A1). These can be used alone or in admixture of two or more.

As another monomer (1-C3) which has a double bond, the monomer similar to the other monomer (1-A3) which has a double bond is mentioned, for example. These can be used alone or in admixture of two or more.

51-100 mass% is mentioned as content of the alkyl methacrylate (1-C1) in the monomer component for obtaining outermost layer polymer (1-C).

  Examples of the content of the alkyl acrylate (1-C2) in the monomer component for obtaining the outermost layer polymer (1-C) include 0 to 20% by mass.

  0-49 mass% is mentioned as content of the monomer (1-C3) which has a double bond.

  As said chain transfer agent, the chain transfer agent similar to the chain transfer agent used in order to obtain innermost layer polymer (1-A) is mentioned, It can use individually or in mixture of 2 or more types.

The content of the chain transfer agent in the monomer component for obtaining the outermost layer polymer (1-C) is 100 parts by mass of the monomer component for obtaining the outermost layer polymer (1-C). 0.01 to 5 parts by mass.


<Method for Producing Multilayer Structure Polymer (1)>

As a production method of the multilayer structure polymer (1), for example, a sequential multistage emulsion polymerization method, and an innermost layer polymer (1-A) and an intermediate layer polymer (1-B) were obtained by a sequential multistage emulsion polymerization method. An emulsion suspension polymerization method in which the outermost layer polymer (1-C) is converted into a suspension polymerization system later when polymerized is used.

  As a method for producing the multilayer structure polymer (1) by the sequential multi-stage emulsion polymerization method, for example, the monomer component for obtaining the innermost layer polymer (1-A), water and a surfactant are mixed and prepared. After supplying the obtained emulsion to the reactor for polymerization, a monomer component for obtaining the intermediate layer polymer (1-B) and a monomer component for obtaining the outermost layer polymer (1-C) Examples thereof include a method in which each is supplied to the reactor in order and polymerized.

  By obtaining the multilayer structure polymer (1) by the above-described method, when the obtained latex is dispersed in acetone, the number of particles having a diameter of 55 μm or more present in the dispersion is reduced to the multilayer structure polymer ( 1) The multilayer structure polymer (1) which is 0-50 per 100g can be obtained easily.

  The acrylic resin film obtained by using the multilayer structure polymer (1) obtained by the above method is preferable in terms of the characteristic that the number of fish eyes in the film is small.

  Examples of the surfactant used when producing the multilayer structure polymer (1) by the sequential multistage emulsion polymerization method include anionic, cationic and nonionic surfactants. These can be used alone or in admixture of two or more.

  Examples of anionic surfactants include rosin soap, potassium oleate, sodium stearate, sodium myristate, sodium N-lauroylsarcosate, dipotassium alkenyl succinate; sulfate esters such as sodium lauryl sulfate Salts: Sodium dioctyl sulfosuccinate, sodium dodecylbenzenesulfonate, sodium alkyldiphenyl ether disulfonate, etc .; and phosphate esters such as polyoxyethylene alkylphenyl ether sodium phosphate, polyoxyethylene alkyl ether sodium phosphate Salt.

  Specific examples of commercially available anionic surfactants include Eleminol NC-718 manufactured by Sanyo Kasei Kogyo Co., Ltd., Phosphanol LS-529, Phosphanol RS-610NA manufactured by Toho Chemical Co., Ltd., Phosphanol RS-620NA, Phosphanol RS-630NA, Phosphanol RS-640NA, Phosphanol RS-650NA and Phosphanol RS-660NA, and LATEMUL P-0404 and LATEMUL P-0405 manufactured by Kao Corporation , Latemul P-0406 and Latemul P-0407 (both are trade names).

  As a method for preparing an emulsion by mixing the monomer component, water and a surfactant for obtaining the innermost layer polymer (1-A), for example, the innermost layer polymer (1-A) is submerged in water. Method of charging a surfactant after charging a monomer component for obtaining; Method of charging a monomer component for obtaining an innermost layer polymer (1-A) after charging a surfactant in water And a method of adding water after charging the surfactant into the monomer component for obtaining the innermost layer polymer (1-A).

  As a mixing device for preparing an emulsion by mixing the monomer component for obtaining the innermost layer polymer (1-A) with water and a surfactant, for example, a stirrer equipped with a stirring blade; a homogenizer, And a forced emulsification device such as a homomixer; and a membrane emulsification device.

  As the above-mentioned emulsion, W / O type in which water droplets are dispersed in oil as a monomer component for obtaining the innermost layer polymer (1-A), the innermost layer polymer (1-A) is obtained in water. Therefore, any O / W type dispersion in which oil droplets of the monomer component are dispersed can be used.

  The latex of the multilayer structure polymer (1) obtained by the above method can be treated by using a filtration device provided with a filter medium as necessary. This filtration treatment is used to remove scales generated during the polymerization from the latex of the multilayer structure polymer (1), or to remove foreign substances mixed in the polymerization raw material or during the polymerization.

  As a filtering device in which the above filter medium is arranged, for example, a GAF filter system of ISP Filters PTE Ltd. using a bag-like mesh filter, a cylindrical filter medium is arranged on the inner surface of a cylindrical filter chamber, Examples thereof include a centrifugal separator having a stirring blade disposed in the filter medium, and a vibration filter apparatus in which the filter medium performs a horizontal circular motion and a vertical amplitude motion with respect to the filter medium surface.

  The multilayer structure polymer (1) is obtained as a powder by recovering from the latex of the multilayer structure polymer (1).

  Examples of the method for recovering the multilayer structure polymer (1) from the latex of the multilayer structure polymer (1) include a coagulation method by salting out or acid precipitation, a spray drying method, and a freeze drying method.

  When the multilayer structure polymer (1) is recovered by a coagulation method by salting out using a metal salt, the residual metal content in the finally obtained multilayer structure polymer (1) is 800 ppm or less. It is preferable that a smaller amount is more preferable.

  When a metal salt having a strong affinity with water such as calcium, magnesium, sodium, etc., preferably a calcium salt, is used as the metal salt in the salting-out treatment, the residual metal content in the multilayer structure polymer (1) As much as possible, the whitening phenomenon when the acrylic resin film is immersed in boiling water tends to be suppressed.

  As a polymerization initiator used in forming the innermost layer polymer (1-A), the intermediate layer polymer (1-B) and the outermost layer polymer (1-C) in the multilayer structure polymer (1). Known methods can be used, and examples of the addition method include a method of adding to one of the aqueous phase and the monomer phase, or a method of adding to both.

Examples of the polymerization initiator include peroxides, azo initiators, and redox initiators in which a peroxide or azo initiator is combined with an oxidizing agent / reducing agent.

Specific examples of redox initiators include sulfoxylate initiators in which ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, longalite, and hydroperoxide are combined.

  In the present invention, as a method for producing a latex of the multilayer structure polymer (1), an emulsion prepared by mixing a monomer component for obtaining the innermost layer polymer (1-A) with water and a surfactant. When the intermediate layer polymer (1-B) is formed after supplying the polymer to the reactor, the monomer component for obtaining the intermediate layer polymer (1-B), and the outermost layer polymer ( In the case where the monomer components for obtaining 1-C) are sequentially supplied to the reactor for polymerization, an aqueous solution in a polymerization vessel containing ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, Rongalite Is heated to the polymerization temperature, and then an emulsion prepared by mixing the monomer component for obtaining the innermost layer polymer (1-A) with water and a surfactant is supplied to the reactor for polymerization. Next, when forming the intermediate layer polymer (1-B), a polymerization initiator is added. The monomer component mixture for obtaining the intermediate layer polymer (1-B) and the monomer component mixture for obtaining the outermost layer polymer (1-C) are sequentially supplied to the reactor for polymerization. Is preferred.

In the present invention, the polymerization temperature for obtaining the latex of the multilayer structure polymer (1) varies depending on the kind and amount of the polymerization initiator to be used, and examples thereof include 40 to 120 ° C.

<Thermoplastic polymer (2)>

As a thermoplastic polymer (2) used by this invention, the polymer which has an alkyl methacrylate unit as a main component is mentioned, for example.

  As the polymer having an alkyl methacrylate unit as a main component, from the viewpoint of heat resistance of the acrylic resin film, the alkyl methacrylate is 50 to 100% by mass, the alkyl acrylate is 0 to 50% by mass, and these are copolymerizable with these. A polymer obtained by polymerizing a monomer component containing 0 to 49% by mass of another monomer having a heavy bond is preferred.

  The load of the thermoplastic polymer (2) obtained by measuring according to JIS K 7191 with a load of 1.82 MPa when using a test specimen for measuring the deflection temperature under load based on JIS K 7191 created from the thermoplastic polymer (2). The deflection temperature is preferably 90 to 150 ° C. The deflection temperature under load of the thermoplastic polymer (2) is 90 ° C. or higher, and the main HDT of the acrylic resin (A) tends to be easily set to 80 to 130 ° C.

  Examples of the alkyl methacrylate used for the monomer component for obtaining the thermoplastic polymer (2) include the same monomers as the alkyl methacrylate (1-A2). These can be used alone or in admixture of two or more.

  As content of the alkyl methacrylate in the monomer component for obtaining a thermoplastic polymer (2), 50-100 mass% is preferable at the heat resistant point of this acrylic resin film, and 85-99.9. The mass% is more preferable, and 92 to 99.9 mass% is still more preferable.

  Examples of the alkyl acrylate contained as necessary in the monomer component for obtaining the thermoplastic polymer (2) include the same monomers as the alkyl acrylate (1-A1). These can be used alone or in admixture of two or more.

  As content of the alkyl acrylate in the monomer component for obtaining a thermoplastic polymer (2), 0-50 mass% is preferable at the heat resistant point of this acrylic resin film, 0.1-40 % By mass is more preferable, 0.1 to 15% by mass is further preferable, and 0.1 to 8% by mass is particularly preferable.

  The other monomer having a double bond in the monomer component for obtaining the thermoplastic polymer (2) is the same amount as the other monomer (1-A3) having a double bond. The body is mentioned. These can be used alone or in admixture of two or more.

  As content of the other monomer which has a double bond in a monomer component for obtaining a thermoplastic polymer (2), 0-49 mass% is a heat resistant point of this acrylic resin film. preferable.

Examples of the polymerization method of the thermoplastic polymer (2) include a suspension polymerization method, an emulsion polymerization method, and a bulk polymerization method.

Surfactant (B)

Examples of the surfactant (B) used in the present invention include anionic, cationic and nonionic surfactants. These can be used alone or in admixture of two or more.

Specific examples of commercially available surfactants (B) include Phosphanol RS-610NA manufactured by Toho Chemical Industry Co., Ltd. and Aerosol OT (all trade names) manufactured by Mitsui Cytec Co., Ltd.

Acrylic resin composition (C)

The acrylic resin composition (C) used in the present invention contains an acrylic resin (A) and a surfactant (B).

  As content of the acrylic resin (A) and surfactant (B) in an acrylic resin composition (C), surfactant (B) 0.1-3. 8 parts by mass.

  Examples of the shape of the acrylic resin composition (C) include a lump, a powder, and a pellet. Among these, pellets are preferable from the viewpoint of the handleability of the acrylic resin composition (C).

  By making content of surfactant (B) into 0.1 mass part or more, the mold release of this acrylic resin film mentioned later from the metal mold | die which has a fine structure becomes easy. Moreover, blocking of the acrylic resin composition (C) when pelletizing the acrylic resin composition (C) can be suppressed by setting the content of the surfactant (B) to 3.8 parts by mass or less. The extrusion process of the resin composition (C) becomes easy.

  As a method for adding the surfactant (B) to the acrylic resin (A), for example, a method of adding the acrylic resin composition (C) before making it into a pellet and an acrylic resin (A) as a pellet The method of adding to is mentioned. Among these, the method of adding before making an acrylic resin composition (C) into a pellet-like thing is preferable at the point of the handleability of an acrylic resin composition (C).

  In the present invention, in the acrylic resin composition (C), if necessary, a stabilizer, a lubricant, a processing aid, a matting agent, a light diffusing agent, a plasticizer, an impact resistance aid, a foaming agent, a filling agent. Various compounding agents such as an agent, a colorant, an antibacterial agent, an antifungal agent, a mold release agent, an antistatic agent, a light stabilizer, and an ultraviolet absorber can be included.

  In the present invention, the acrylic resin composition (C) may contain an ultraviolet absorber in terms of imparting the weather resistance of the acrylic resin film for protecting the product using the acrylic resin film. preferable.

  As a molecular weight of the ultraviolet absorber mix | blended in an acrylic resin composition (C), 300 or more are preferable and 400 or more are more preferable. The molecular weight of the ultraviolet absorber is 300 or more, and the mold used for producing the acrylic resin film tends to be prevented from being soiled.

  As a kind of ultraviolet absorber, a benzotriazole type ultraviolet absorber and a triazine type ultraviolet absorber are mentioned, for example.

  Examples of commercially available benzotriazole-based ultraviolet absorbers include Ciba Geigy's Tinuvin 234 and Adeka Stub LA-31 manufactured by Asahi Denka Kogyo Co., Ltd.

As a commercial item of a triazine type ultraviolet absorber, for example, Tinuvin 1577 (trade name) manufactured by Ciba Geigy is listed.

This acrylic resin film

This acrylic resin film is obtained by molding the acrylic resin composition (C).

  As thickness of this acrylic resin film, 10-500 micrometers is preferable and 30-200 micrometers is more preferable at the point of the handleability of this acrylic resin film.

  As the elongation of the acrylic resin film, a tensile test piece based on the test piece type 2 described in JIS K7127 obtained by using the acrylic resin film having a thickness of 175 μm was used. The elongation when measured according to JIS K7127 at a speed of minutes is preferably 10 to 350% in terms of process passability when transferring the fine structure to the surface of the acrylic resin film. When the elongation of the acrylic resin film is 10% or more, preferably 20% or more, more preferably 30% or more, and the microstructure is formed on the surface of the acrylic resin film by transfer from a mold having a microstructure. The acrylic resin film tends to be handled without breaking, and the handling property of the acrylic resin film tends to be kept good. Further, the elongation of the acrylic resin film is 350% or less, preferably 340% or less, more preferably 330% or less, and the release property of the acrylic resin film from the mold having a fine structure can be kept good. It tends to be possible.

  Examples of the method for producing the acrylic resin film include a melt extrusion method such as a melt casting method, a T-die method, and an inflation method, and a calendar method, but the T-die method is preferable from the viewpoint of economy.

  When the acrylic resin film is produced by a melt extrusion method such as a T-die method, an acrylic resin composition (C) in a molten state with a screen mesh of 200 mesh or more, preferably 300 mesh or more, more preferably 500 mesh or more. ) Is preferably extruded while filtering.

  The acrylic resin film can be formed into a roll-shaped article by forming the film with an extruder or the like and then winding the film on a tubular object such as a paper tube with a winder.

  Examples of a method for forming a fine structure on the surface of the acrylic resin film include a thermal transfer method and an etching method.

  Among these, the thermal transfer method that forms a microstructure on the surface of the acrylic resin film by pressing the heated mold on the surface of the acrylic resin film after heating the mold having a microstructure is productive. And preferable in terms of economy.

  As the above-mentioned thermal transfer method, for example, a method of heating and pressing a fine structure on a single sheet by heating and pressing the acrylic resin film cut out from the roll-shaped article with a fine structure and a heated belt-like fine structure There is a continuous forming method in which the acrylic resin film unwound from the roll-shaped article is sandwiched and pressed using a nip roll in a mold having a structure, and the microstructure is thermally transferred onto the surface of the acrylic resin film.

  The mold temperature of the mold having a fine structure at the time of thermal transfer is 130 to 250 ° C, preferably 140 to 240 ° C, and more preferably 150 to 230 ° C. When the mold temperature is 130 ° C. or higher, a uniform fine structure tends to be formed on the surface of the acrylic resin film. Further, the mold temperature is 250 ° C. or less, and the process tends to be allowed to pass through without deforming the fine structure formed on the surface of the acrylic resin film.

  Examples of a method for producing a mold having the above-described fine structure include a sand blast method, an etching method, and an electric discharge machining method.

  Specific examples of the method for producing a mold having a fine structure include the following methods.

  First, a fine structure of a desired size is formed on a metal base material such as copper whose surface is ground flat by a cutting method, and a male mold having the fine structure is created.

  Next, a metal film is formed on the surface of the obtained male mold by electroforming, and the metal film having a fine structure obtained by removing the metal film from the male mold is defined as a mold. To do.

The obtained mold can be joined and processed into a desired size or belt shape.

Retroreflective sheet

The retroreflective sheet of the present invention is obtained by heat-pressing a mold having a fine structure on the surface of the acrylic resin film and then removing the acrylic resin film from the mold, and having an acrylic resin film having a fine structure on the surface. It is manufactured using it.

Hereinafter, the present invention will be described based on examples. In the following, “part” represents “part by mass”, and “%” represents “mass%”. The abbreviations used in the following description are as follows.
MMA: methyl methacrylate MA: methyl acrylate n-BA: n-butyl acrylate St: styrene 1,3-BD: 1,3-butylene glycol dimethacrylate AMA: allyl methacrylate CHP: cumene hydroperoxide t-BH: t-butyl Hydroperoxide n-OM: n-octyl mercaptan EDTA: disodium ethylenediaminetetraacetate SFS: sodium formaldehyde sulfoxylate RS610NA: sodium polyoxyethylene alkyl ether phosphate (trade name: Phospha Nord RS610NA)
In the present invention, various evaluations on the multilayer structure polymer (1), the thermoplastic polymer (2), the acrylic resin film, and the retroreflective sheet were performed by the following methods.
(1) Deflection temperature under load of thermoplastic polymer (2) Using the thermoplastic polymer (2), a test piece for measurement of deflection temperature under load according to JIS K 7191 was prepared by injection molding, and annealed at 60 ° C for 4 hours. After the measurement, the deflection temperature under load of the thermoplastic polymer (2) was measured according to JIS K 7191 with a load of 1.82 MPa.
(2) Extrudability of acrylic resin composition Acrylic resin composition powder is supplied to a degassing extruder (Toshiba Machine Co., Ltd., trade name: TEM-35B) heated to 230 ° C and kneaded. The extrudability of the acrylic resin composition when obtaining the pellets was evaluated according to the following criteria.
○: Good extrusion (no blocking of powder in raw material supply hopper)
×: Cannot be extruded (powder blocking occurs in the raw material supply hopper, and cannot be pelletized)
(3) Acrylic resin HDT
Using a pellet-shaped acrylic resin used as a raw material for the acrylic resin film, a heat deformation temperature measurement test piece having a length of 127 mm, a width of 6.4 mm and a height of 12.7 mm based on ASTM D648 is prepared by an injection molding method. Annealing was performed at 60 ° C. for 4 hours.

Next, using this test piece, an HDT measurement test was performed in accordance with ASTM D648 under the conditions of a span length of 101.6 mm by Method A, a load of 0.45 MPa, a temperature rising rate of 2 ° C./min, and an edgewise condition. This HDT of the acrylic resin was measured when the amount of deformation reached 0.25 mm.
(4) Elongation of acrylic resin film An acrylic resin film having a thickness of 175 μm was prepared, and a tensile test piece based on the test piece type 2 described in JISK7127 was used as a tensile test piece with a distance between chucks of 100 mm and a tensile speed of 100 mm / In minutes, the elongation of the acrylic resin film was measured according to JIS K7127.
(5) Mirror Mold Releasability of Acrylic Resin Film Acrylic resin film having a thickness of 175 μm cut to a width of 10 cm and a length of 25 cm is sandwiched between a stainless steel mirror mold and a polytetrafluoroethylene sheet, and a temperature of 200 ° C. and 0 After pressurizing for 10 minutes at a pressure of 5 MPa, pressurization was further performed for 10 minutes at a pressure of 2.0 MPa, and an acrylic resin film was attached to the mold.

Next, the mirror surface metal of the acrylic resin film when the film is peeled by hand at an angle of 90 ° at each temperature when the surface temperature of the acrylic resin film attached to the mold becomes 110 ° C., 90 ° C., and 70 ° C. Mold releasability was evaluated according to the following criteria.
A: It peels off without difficulty.
○: Peel off with slight force.
Δ: Peel off when force is applied.
X: Even if force is applied, it does not peel off or the film tears when it is peeled off.

In addition, the surface roughness (Ra) of a stainless steel mirror mold was measured at a measurement magnification of 100 times and a measurement pitch of 0.05 μm using an ultra-deep surface shape measurement microscope (manufactured by Keyence Corporation, product name: VK-8500). As a result, it was 20 to 40 nm.
(6) Blocking property of acrylic resin film during prism shape transfer Acrylic resin film unwound from a roll-shaped article of acrylic resin film and conveyed to a belt-shaped mold having a prism shape heated to 150 to 180 ° C. In the step of transferring the prism shape by pressing the acrylic resin film to the mold by sandwiching with a nip roll, the blocking property of the acrylic resin film when the acrylic resin film was unwound was evaluated according to the following criteria.
○: Can be transported without sticking.
X: There is sticking and conveyance is impossible.
(7) Prism mold releasability of acrylic resin film during prism shape transfer Belt shape having a prism shape in which an acrylic resin film unwound from a roll-shaped article of acrylic resin film and heated to 150 to 180 ° C. In the process of releasing the acrylic resin film from the mold after the prism shape is transferred by pressing the acrylic resin film to the mold by sandwiching the mold with a nip roll, the release of the acrylic resin film from the mold Sex was evaluated according to the following criteria.
○: Good releasability.
Δ: Slight film sticks to the mold, but release is possible.
X: The film sticks to the mold and cannot be released.
(8) Handling of acrylic resin film during prism shape transfer Acrylic resin film unwound from a roll-shaped article of acrylic resin film and conveyed to a belt-shaped mold having a prism shape heated to 150 to 180 ° C Handling the acrylic resin film during mold release from the mold in the process of releasing the acrylic resin film from the mold after transferring the prism shape by pressing the acrylic resin film to the mold by sandwiching with a nip roll Sex was evaluated according to the following criteria.
○: No breakage of the film.
Δ: Although the film may break, it can be used.
X: Always broken. Cannot be used.

[Preparation Example 1] Production of multilayer structure polymer (1-1) In a nitrogen atmosphere, 204 parts of deionized water was placed in a reaction vessel equipped with a stirrer and a reflux condenser, and the temperature was raised to 80 ° C. Raw material (I) was added.

  Next, 1/10 of the mixture of raw materials (b) shown below was charged while stirring the liquid in the reaction vessel, and held for 15 minutes.

Further, the remainder of the raw material (b) was continuously added to the reaction vessel so that the rate of increase of the monomer mixture with respect to water was 8% / hour, and then held for 1 hour, and the innermost polymer inner layer ( 1-1-A ₁ ) latex was obtained.

Subsequently, 0.12 part of SFS was added to the latex of the innermost layer polymer inner layer (1-1-A ₁ ), held for 15 minutes, and stirred at 80 ° C. in a nitrogen atmosphere, with the following raw materials (c) Was added continuously so that the rate of increase of the monomer mixture with respect to water was 4% / hour, and then kept for 2 hours to form the innermost polymer outer layer (1-1-A ₂ ), A latex of the innermost layer polymer (1-1-A) was obtained.

  Next, 0.12 part of SFS was added to the latex of the innermost layer polymer (1-1-A), held for 15 minutes, and while stirring at 80 ° C. in a nitrogen atmosphere, the following raw material (d) was simply added to water. After the continuous addition so that the rate of increase of the monomer mixture is 10% / hour, the outermost layer polymer (1-1-C) is formed by holding for 1 hour, and the multilayer structure polymer (1- The latex of 1) was obtained.

The latex of the obtained multilayer structure polymer (1-1) was filtered using a vibration type filtration device in which a SUS mesh (average opening: 150 μm) was attached to the filter medium, and then acetic acid was added to 306 parts of deionized water. After salting out in an aqueous solution containing 3 parts of calcium, washing with water and recovering, it was dried to obtain a powdery multilayer structure polymer (1-1). The composition of the multilayer structure polymer (1-1) is shown in Table 1.
<Raw material (I)>
SFS 0.25 part Ferrous sulfate 0.00002 part EDTA 0.00007 part <Raw material (b)>
MMA 11.2 parts n-BA 12.4 parts St 1.2 parts AMA 0.1 part 1,3-BD 0.7 part t-BH 0.04 part RS610NA 0.7 part <Raw material (c)>
n-BA 30.7 parts St 6.5 parts AMA 0.65 parts 1,3-BD 0.1 part CHP 0.11 part RS610NA 0.59 parts <Raw material (d)>
MMA 35.3 parts MA 1.9 parts n-OM 0.11 parts t-BH 0.06 parts

★
表１中の略号は以下の化合物を示す。
ＭＭＡ： メチルメタクリレート
ｎ−ＢＡ： ｎ−ブチルアクリレート
Ｓｔ： スチレン
ＡＭＡ： アリルメタクリレート
１，３−ＢＤ： １，３−ブチレングリコールジメタクリレート
ｔ−ＢＨ： ｔ−ブチルハイドロパーオキサイド
ＲＳ６１０ＮＡ：ポリオキシエチレンアルキルエーテルリン酸ナトリウム（東邦化学工業（株）製、商品名：フォスファノールＲＳ６１０ＮＡ）
ＣＨＰ： クメンハイドロパーオキサイド
ＭＡ： メチルアクリレート
ｎ−ＯＭ： ｎ−オクチルメルカプタン
［調製例２］多層構造重合体（１−２）の製造
攪拌機を備えた容器内に脱イオン水１０．８部を仕込んだ後、ＭＭＡ０．３部、ｎ−ＢＡ４．５部、１，３−ＢＤ０．２部、ＡＭＡ０．０５部及びＣＨＰ０．０２５部を含有する単量体成分を投入し、室温下にて攪拌混合した。

★
The abbreviations in Table 1 indicate the following compounds.
MMA: methyl methacrylate n-BA: n-butyl acrylate St: styrene AMA: allyl methacrylate 1,3-BD: 1,3-butylene glycol dimethacrylate t-BH: t-butyl hydroperoxide RS610NA: polyoxyethylene alkyl ether Sodium phosphate (trade name: Phosphanol RS610NA, manufactured by Toho Chemical Industry Co., Ltd.)
CHP: cumene hydroperoxide MA: methyl acrylate n-OM: n-octyl mercaptan [Preparation Example 2] Production of multilayer structure polymer (1-2) 10.8 parts of deionized water was charged in a vessel equipped with a stirrer. Thereafter, a monomer component containing 0.3 part of MMA, 4.5 part of n-BA, 0.2 part of 1,3-BD, 0.05 part of AMA and 0.025 part of CHP is added and stirred and mixed at room temperature. did.

  Next, 1.3 parts of RS610NA as an emulsifier was charged into the container while stirring in the container, and stirring was continued for 20 minutes to prepare an emulsion.

  Into a reaction vessel equipped with a stirrer and a reflux condenser, 139.2 parts of deionized water was charged and the temperature was raised to 75 ° C.

  Further, a mixture prepared by adding 0.20 part of SFS, 0.0001 part of ferrous sulfate and 0.0003 part of EDTA to 5 parts of ion-exchanged water was put into the above reaction vessel at once.

Next, while stirring the inside of the reaction vessel under nitrogen, the above emulsion was dropped into the polymerization vessel over 8 minutes while stirring at 75 ° C. under a nitrogen atmosphere, and then the reaction was continued for 15 minutes, and the innermost layer weight was increased. A latex of the combined inner layer (1-2-A ₁ ) was obtained.

Subsequently, the monomer component containing 9.6 parts of MMA, 14.4 parts of n-BA, 1.0 part of 1,3-BD, and 0.25 part of AMA was stirred together with 0.016 part of CHP at 75 ° C. in a nitrogen atmosphere. Then, after dropping into the reaction vessel over 90 minutes, the reaction is continued for 60 minutes to form the innermost layer polymer outer layer (1-2-A ₂ ) to form the innermost layer polymer (1-2-A). Latex was obtained.

  Furthermore, the monomer component containing 6 parts of MMA, 4 parts of MA and 0.075 part of AMA was dropped into the reaction vessel over 45 minutes while stirring at 75 ° C. in a nitrogen atmosphere together with 0.0125 part of CHP, and then reacted for 60 minutes. Was continued to form an intermediate layer polymer (1-2-B).

  Subsequently, a monomer component containing 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 reaction vessel over 140 minutes while stirring at 75 ° C. in a nitrogen atmosphere. Thereafter, the reaction was continued for 60 minutes to form the outermost layer polymer (1-2C) to obtain a latex of the multilayer structure polymer (1-2).

The latex of the obtained multilayer structure polymer (1-2) was filtered using a vibration type filtration device in which a SUS mesh (average opening: 62 μm) was attached to the filter medium, and acetic acid was added to 257 parts of deionized water. After salting out in an aqueous solution containing 3.5 parts of calcium, washing with water, and recovering, a powdery multilayer structure polymer (1-2) was obtained. The composition of the multilayer structure polymer (1-2) is shown in Table 1.
[Preparation Example 3] Production of multi-layered polymer (1-3) Raw material (e) was charged into a reaction vessel equipped with a stirrer and a reflux condenser, and the temperature was raised to 70 ° C. I put it in.

  Next, while stirring the raw material (g) in a reaction vessel at 80 ° C. in a nitrogen atmosphere, the solution was dropped in 185 minutes and then held for 120 minutes to obtain a latex of the innermost layer polymer (1-3-A). .

  Subsequently, the raw material (h) was charged all at once at 80 ° C. in a nitrogen atmosphere while stirring in the reaction vessel, and then 15 minutes later, the raw material (li) was dropped over 90 minutes and then held for 60 minutes. The outer layer polymer (1-3-C) was formed to obtain a latex of the multilayer structure polymer (1-3).

The latex of the obtained multilayer structure polymer (1-3) was filtered using a vibration type filtration device in which a SUS mesh (average opening: 62 μm) was attached to the filter medium, and then acetic acid was added to 296 parts of deionized water. Salting out was carried out in an aqueous solution containing 2.5 parts of calcium, and the polymer was washed with 20 times the amount of pure water, dehydrated and dried to obtain a powdery multilayer structure polymer (1-3). The composition of the multilayer structure polymer (1-3) is shown in Table 1.
<Raw material (e)>
Ion-exchanged water 188 parts Sodium carbonate 0.03 parts RS610NA 0.63 parts <Raw material (f)>
Ion-exchanged water 53.1 parts SFS 0.3 parts Ferrous sulfate 0.00003 parts EDTA 0.00008 parts <Raw material (g)>
n-BA 50.9 parts St 11.6 parts AMA 0.56 parts t-BH 0.19 parts RS610NA 1.0 part <Raw material (H)>
Deionized water 3.1 parts SFS 0.08 parts <Raw material (re)>
MMA 35.6 parts MA 1.9 parts n-OM 0.16 parts t-BH 0.06 parts RS610NA 0.25 parts [Preparation Example 4] Production of multilayer structure polymer (1-4) Container equipped with a stirrer Monomer containing 8.5 parts deionized water, 4.5 parts MMA, 4.5 parts n-BA, 0.2 parts 1,3-BD, 0.05 parts AMA and 0.025 parts CHP The components were added and stirred and mixed at room temperature.

  Next, 1.3 parts of RS610NA as an emulsifier was charged into the container while stirring, and stirring was continued for 20 minutes to prepare an emulsion.

  Into a reaction vessel equipped with a stirrer and a reflux condenser, 186.5 parts of deionized water was charged and the temperature was raised to 70 ° C.

  Further, a mixture prepared by adding 0.20 part of SFS, 0.0001 part of ferrous sulfate and 0.0003 part of EDTA to 5 parts of ion-exchanged water was put into the above reaction vessel at once.

Next, while stirring the reaction vessel at 75 ° C. in a nitrogen atmosphere, the above emulsion was dropped into the reaction vessel over 8 minutes, and then the reaction was continued for 15 minutes, whereby the innermost polymer inner layer (1-4 obtain a latex of -A _1).

Subsequently, the monomer component containing 1.5 parts of MMA, 22.5 parts of n-BA, 1.0 part of 1,3-BD and 0.25 part of AMA was stirred together with 0.016 part of CHP at 75 ° C. in a nitrogen atmosphere. Then, after dropping into the reaction vessel over 90 minutes, the reaction was continued for 60 minutes to form the innermost layer polymer outer layer (1-4-A ₂ ), and the innermost layer polymer (1-4-A) Furthermore, a monomer component containing 6 parts of MMA, 4 parts of n-BA and 0.075 part of AMA was dropped into the reaction vessel over 45 minutes while stirring at 75 ° C. in a nitrogen atmosphere together with 0.0125 part of CHP. Then, the reaction was continued for 60 minutes to form an intermediate layer polymer (1-4-B).

  Subsequently, while stirring the monomer component containing 55.2 parts of MMA, 4.8 parts of n-BA, 0.19 part of n-OM and 0.08 part of t-BH at 75 ° C. in a nitrogen atmosphere, over 140 minutes. After dripping in the reaction vessel, the reaction was continued for 60 minutes to form the outermost layer polymer (1-4-C) to obtain a latex of the multilayer structure polymer (1-4).

The latex of the obtained multilayer structure polymer (1-4) was filtered using a vibration type filtration device in which a SUS mesh (average opening: 62 μm) was attached to the filter medium, and then acetic acid was added to 302 parts of deionized water. Salting out was carried out in an aqueous solution containing 3 parts of calcium, washed with water, recovered, and dried to obtain a powdery multilayer structure polymer (1-4). The composition of the multilayer structure polymer (1-4) is shown in Table 1.
[Example 1]
MMA / MA copolymer (MMA / MA = 99/1 (mass ratio) as multilayer polymer (1-1) 10 parts, multilayer polymer (1-2) 70 parts and thermoplastic polymer (2) , Deflection temperature under load: 101 ° C.) 100 parts of acrylic resin (A) containing 20 parts, Adeka Stub LA-31RG (trade name) manufactured by ADEKA as a compounding agent, 0.6 part of Adeka Stub LA-57 (( ADEKA Co., Ltd., trade name: 0.2 parts and Irganox 1076 (Ciba Specialty Chemicals Co., Ltd., trade name) 0.1 parts were added, and phosphanol RS610NA as a surfactant (B). (Toho Chemical Industry Co., Ltd. polyoxyethylene alkyl ether sodium phosphate, trade name) 0.275 parts was added and mixed with a Henschel mixer, acrylic resin composition (C) Obtained.

  The above acrylic resin composition (C) is supplied to a degassing extruder (trade name: TEM-35B, manufactured by Toshiba Machine Co., Ltd.) heated to 230 ° C. and kneaded to obtain an acrylic resin composition (C). Pellets were obtained. When the acrylic resin composition (C) was supplied to the extruder, blocking of the acrylic resin composition (C) at the hopper portion of the extruder did not occur and good extrudability was exhibited.

  When this HDT was measured using the pellet of the obtained acrylic resin composition (C), this HDT was 88.2 degreeC.

  The obtained acrylic resin composition (C) pellets were subjected to a cylinder temperature of 200 ° C. to 240 ° C. and a T die using a 40 mmφ non-vent screw extruder (L / D = 26) equipped with a 300 mm wide T die. A film was formed under conditions of a temperature of 250 ° C. and a cooling roll temperature of 80 ° C., and the obtained acrylic resin film was wound around a paper tube with a winder to obtain a roll-shaped article of 175 μm thick acrylic resin film. The elongation of the obtained acrylic resin film was 85%, and the mold release property was good.

  Next, the acrylic resin film is unwound and conveyed from the roll-shaped article of the acrylic resin film, and the acrylic resin film is sandwiched between belt-shaped molds having a prism shape heated to 150 to 180 ° C. using a nip roll, The prism shape was transferred to the surface of the acrylic resin film. In this step, there was no sticking between the films when the acrylic resin film was unwound from the roll-shaped article of the acrylic resin film, and the blocking property of the acrylic resin film was good. Furthermore, the release of the acrylic resin film from the mold was possible although the acrylic resin film was slightly attached to the mold. Further, the film was not broken after the release. The results are shown in Table 2.

  In the above process, a metal mold having a surface temperature of about 190 ° C., in which an acrylic resin film having a prism shape transferred on its surface and a polyethylene terephthalate film having a binder layer are subjected to a mesh-like convex sculpture with a line width of 0.3 mm Between the rubber roll and the rubber roll, the prism shape was passed while pressing so as to be in contact with the rubber roll to form a hermetically sealed structure by a heat sealing method, and a retroreflective sheet was produced. The obtained retroreflective sheet exhibited good retroreflective performance.

★
表２中の略号は以下の化合物を示す。
ＲＳ６１０ＮＡ：ポリオキシエチレンアルキルエーテルリン酸ナトリウム（東邦化学工業（株）製、商品名：フォスファノールＲＳ６１０ＮＡ）
ＡＯＴ：スルホコハク酸ジ（２−エチルヘキシル）ナトリウム（三井サイテック（株）製、商品名：エアロゾルＯＴ）
ＬＡ−３１ＲＧ：アデカスタブＬＡ−３１ＲＧ（（株）ＡＤＥＫＡ製、商品名）
ＬＡ−５７：アデカスタブＬＡ−５７（（株）ＡＤＥＫＡ製、商品名）
イルガノックス１０７６：チバ・スペシャルティ・ケミカルズ（株）製、商品名
［実施例２〜５］
界面活性剤であるＲＳ６１０ＮＡの添加量を表２に示す量とした以外は実施例１と同様にしてアクリル樹脂フィルムのロール状物品を得た。各種評価結果を表２に示す。

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The abbreviations in Table 2 indicate the following compounds.
RS610NA: Sodium polyoxyethylene alkyl ether phosphate (manufactured by Toho Chemical Co., Ltd., trade name: Phosphanol RS610NA)
AOT: Sodium di (2-ethylhexyl) sulfosuccinate (Mitsui Cytec Co., Ltd., trade name: Aerosol OT)
LA-31RG: ADK STAB LA-31RG (trade name, manufactured by ADEKA Corporation)
LA-57: ADK STAB LA-57 (trade name, manufactured by ADEKA Corporation)
Irganox 1076: Ciba Specialty Chemicals Co., Ltd., trade name [Examples 2 to 5]
A roll-shaped article of an acrylic resin film was obtained in the same manner as in Example 1 except that the addition amount of RS610NA as the surfactant was changed to the amount shown in Table 2. Various evaluation results are shown in Table 2.

Moreover, the retroreflective sheet produced from the obtained acrylic resin film showed favorable retroreflective performance.
[Examples 6 to 8]
Example: AOT (sulfosuccinate di (2-ethylhexyl) sodium (Mitsui Cytec Co., Ltd., trade name: Aerosol OT)) was used as the surfactant, and the amount of AOT added was changed to the amount shown in Table 2. In the same manner as in Example 1, a roll-shaped article of an acrylic resin film was obtained. Various evaluation results are shown in Table 2.

Moreover, the retroreflective sheet produced from the obtained acrylic resin film showed favorable retroreflective performance.
[Examples 9 and 10]
The multilayer structure polymer (1) shown in Table 2 was used, and the amounts of the multilayer structure polymer (1), the thermoplastic polymer (2) and the surfactant (B) were set to the amounts shown in Table 2. . Other than that was carried out similarly to Example 1, and obtained the roll-shaped article of the acrylic resin film. Various evaluation results are shown in Table 2.
Moreover, the retroreflective sheet produced from the obtained acrylic resin film showed favorable retroreflective performance.
[Comparative Example 1]
A roll-shaped article of an acrylic resin film was obtained in the same manner as in Example 4 except that 100 parts of the multilayer structure polymer (1-4) was used as the acrylic resin (A). Various evaluation results are shown in Table 2.

When the acrylic resin film was unwound from the roll-shaped article of the acrylic resin film, the films adhered to each other, and the acrylic resin film could not be conveyed.
[Comparative Example 2]
A roll-shaped article of an acrylic resin film was obtained in the same manner as in Comparative Example 1 except that the surfactant was 0.3 part. Various evaluation results are shown in Table 2.

When the acrylic resin film was unwound from the roll-shaped article of the acrylic resin film, the films adhered to each other, and the acrylic resin film could not be conveyed.
[Comparative Examples 3 to 5]
A roll-shaped article of an acrylic resin film was obtained in the same manner as in Example 1 except that the type and addition amount of the surfactant were changed to those shown in Table 2. Various evaluation results are shown in Table 2.

  In Comparative Example 3, the mirror mold mold releasability of the acrylic resin film and the prism mold releasability of the acrylic resin film at the time of prism shape transfer were poor. In Comparative Examples 4 and 5, the acrylic resin composition (C) was supplied to a degassing type extruder and kneaded to obtain pellets of the acrylic resin composition (C). When supplying (C) to the extruder, blocking of the acrylic resin composition (C) occurred in the hopper portion of the extruder, and pellets of the acrylic resin composition (C) could not be obtained.

Claims (4)

100 parts by mass of acrylic resin (A) having an HDT of 80 to 130 ° C. and a surface activity when the thermal deformation amount of the test piece after measuring the thermal deformation temperature (HDT) under the following conditions in accordance with ASTM D648 is 0.25 mm An acrylic resin film obtained from an acrylic resin composition (C) containing 0.1 to 3.8 parts by mass of the agent (B) (based on 100 parts by mass of the acrylic resin (A)).
<HDT measurement conditions>
Test piece: 127 mm in length, 6.4 mm in width and 12.7 mm in height
Span length by Method A: 101.3mm
Load: 0.45 MPa
Temperature increase rate: 2 ° C / min load test piece part: Edgewise   The acrylic resin film according to claim 1, wherein the surfactant (B) contains at least one surfactant selected from a phosphate ester salt (B-1) and a sulfonate salt (B-2).   The manufacturing method of the acrylic resin film which has a fine structure on the surface which peels an acrylic resin film from a metal mold | die after heat-pressing the metal mold | die which has a fine structure on the surface of the acrylic resin film of Claim 1 or 2.   A retroreflective sheet using the acrylic resin film obtained by the method of claim 3.