JP2003286461A - Process for production of ornamental pressure-sensitive adhesive sheet and white toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an advantageous low cost process for production of an ornamental pressure-sensitive adhesive sheet with favorable hiding property of an adherend and a white toner used for its production. <P>SOLUTION: A process for production of the ornamental pressure-sensitive adhesive sheet by preparing a homogenous dispersion of the white toner of a white pigment and an acrylic resin with Tg is -10°C or less and mixing with a pressure-sensitive adhesive to give a white pressure-sensitive adhesive composition comprises 3-50 wt. parts of the white pigment to 100 wt. parts of the pressure-sensitive adhesive and 10-150 wt. parts of the acrylic resin to the white pigment on one side of a colored film with a total light transmittance of 3-80%, and the homogenous dispersion of white toner for the production of the homogeneously dispersed ornamental pressure-sensitive adhesive sheet comprises the white pigment and the acrylic resin with Tg is -10°C or lower. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a decorative pressure-sensitive adhesive sheet used indoors and outdoors and a white toner.

[0002]

2. Description of the Related Art Conventionally, a decorative pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is provided on the surface of a relatively flexible thermoplastic resin film substrate is used, for example, in signboards, advertising towers, shutters, shows used outdoors. A wide range of advertising stickers used for windows, etc .; Stripe stickers for decoration used for vehicles such as automobiles and motorcycles, and ships such as motor boats; Display stickers used for traffic signs, road signs, guide boards, etc. It is used for various purposes and is also called marking sheet (marking film).

The appearance of the product of such a pressure-sensitive adhesive sheet is important, and particularly in the case of a signboard for outdoor decoration, it is required to express a highly saturated color. In order to develop a highly saturated color, two types of methods are roughly known. The first method is a method of applying a white pressure-sensitive adhesive to a transparent colored film and utilizing the fact that the light transmitted through the transparent colored film is reflected by the white pressure-sensitive adhesive layer to improve the saturation. The second method is a method in which a white film layer is further laminated on a transparent colored film and light transmitted through the transparent colored film is reflected by the white film layer to improve the saturation. These two methods are often used in decorative PSA sheets.

However, when the white adhesive is used as in the first method, the amount of the white pigment that can be added to the adhesive is naturally limited, and thus the hiding property of the adherend is limited.
There is a problem that high saturation cannot be obtained, and if the white pigment is added beyond the limit, the required physical properties of the adhesive cannot be satisfied. In addition, it is a good method to make the film into two layers like the second method in order to achieve both the saturation and the hiding property, but it is necessary to produce two kinds of films and laminate them. More processes,
High cost. In addition, since the film thickness is increased due to the two layers, there is a possibility that the workability may be deteriorated or the film may be lifted from the release paper during storage in a roll shape, resulting in an abnormal appearance. .

[0005]

That is, a method for producing a decorative pressure-sensitive adhesive sheet that can satisfy the hiding property of an adherend only by providing a white pressure-sensitive adhesive layer as described above is conventionally known. There wasn't. The present invention has been completed in view of the problems in the conventional method for producing a decorative pressure-sensitive adhesive sheet, focusing on a method for applying a white pressure-sensitive adhesive, the purpose of which is a decoration having excellent adherend concealing properties. An object of the present invention is to provide a cost-effective production method of a pressure-sensitive adhesive sheet for use, and a white toner used in this production method.

[0006]

In order to achieve the above object, the present invention according to claim 1 provides a white pigment and Tg of -10.
A white toner is prepared by uniformly dispersing an acrylic resin having a temperature of not higher than 0 ° C., and a white adhesive composition obtained by mixing the white toner with an adhesive has a total light transmittance of 3 to 80%.
A white adhesive layer containing 3 to 50 parts by weight of a white pigment with respect to 100 parts by weight of an adhesive and containing 10 to 150% by weight of an acrylic resin with respect to the white pigment is formed on one surface of the colored film. A method for producing a decorative pressure-sensitive adhesive sheet is provided.

The present invention according to claim 2 is used in a method for producing a decorative pressure-sensitive adhesive sheet according to claim 1, wherein a white pigment and an acrylic resin having a Tg of -10 ° C or less are uniformly dispersed. Provide white toner. Hereinafter, the present invention will be described in more detail.

In the present invention, the colored film used as the base material of the adhesive sheet for decoration has a total light transmittance of 3 to.
What is 80% is used. If it is lower than 3%, the saturation will not be improved even if a white layer is arranged as a base. On the other hand, if it exceeds 80%, a sufficient hiding property cannot be obtained even if a white layer is arranged as a base. Examples of the material of such a colored film include soft vinyl chloride resin, acrylic resin, polyethylene terephthalate, polyurethane and the like, and soft vinyl chloride resin is preferably used from the viewpoint of various physical properties and cost. A desired color is obtained by blending these resins with various pigments conventionally used for coloring.

Examples of the above-mentioned pigments include azo-based pigments such as lake red C and Hansa yellow, phthalocyanine-based pigments such as phthalocyanine blue and phthalocyanine green, slene-based pigments such as induslen blue and perylene orange, and dye lakes such as rhodamine lake and eosin lake. Examples include quinacridone red, quinacridone magenta, dioxane violet, cadmium yellow, chrome vermillion, carbon black, and titanium oxide.

If desired, a plasticizer, a pigment, a heat stabilizer, a filler, an ultraviolet absorber, a solvent and the like may be added. Examples of the plasticizer include tributyl phosphate, tri-2-ethylhexyl phosphate, triphenyl phosphate, and other phosphate plasticizers, diethyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, and phthalic acid. Examples thereof include phthalic acid-based plasticizers such as diisononyl, adipic acid-based plasticizers such as dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, and diisononyl adipate.

Examples of the heat stabilizer include epoxidized vegetable oils such as epoxidized soybean oil and epoxidized linseed oil, epoxidized fatty acid esters, epoxidized alicyclic compounds such as epoxidized tetrahydrophthalate, and bisphenol A.
Diglycidyl ether, epoxidized polybutadiene, organic stabilizers such as tributyl phosphite, triisooctyl phosphite, Ba / Zn stabilizers, Ba
Examples include metal-based stabilizers such as / Pb-based stabilizers and Ca / Zn-based stabilizers. Among them, the epoxidized soybean oil has a function as a plasticizer in addition to a heat stabilizer, and is suitable for calender molding. 1

Examples of the above-mentioned extender include calcium carbonate, talc (chlorinated magnesium silicate), kaolin (
Aluminum silicate), silica and the like. Examples of the ultraviolet absorber include salicylate-based, O-hydroxybenzophenone-based, and O-hydroxyphenylbenzotriazole-based ultraviolet absorbers, and those having a high molecular weight are excellent in stability over time.

When a vinyl chloride resin is used as a resin for a colored film, as a solvent for the sol, a dispersion solvent that slightly swells the resin at room temperature to promote dispersion and a dispersion solvent that is insoluble in the resin and reduces the sol viscosity are dispersed. It is preferable to mix and use a diluting solvent for suppressing the swelling property of the solvent. In addition, a mixed solvent consisting of petroleum fraction may be used in consideration of industrial profitability. As a dispersion solvent, DIBK, M
Ketones such as IBK, esters such as butyl acetate, glycol ethers, paraffins, naphthenic hydrocarbons, aromatic hydrocarbons, terpenes, etc. as diluent solvents, Solvesso, Exol, petroleum fractions, etc. Isopar (manufactured by Exxon Chemical Co.) is used.

In the present invention, when a white pressure-sensitive adhesive composition is applied to one side of the above colored film, first, a white pigment and an acrylic resin having a Tg of -10 ° C or less are uniformly dispersed to obtain a white toner. Prepare. The acrylic resin used for preparing the white toner has a Tg (glass transition temperature) of −
It needs to be 10 ° C or lower. If the Tg exceeds −10 ° C., when kneading the white pigment and the acrylic resin,
This is because it is difficult to uniformly disperse the white pigment because the acrylic resin is hard. By using an acrylic resin having a Tg of −10 ° C. or less, as will be described later, a sufficient amount of white pigment that can secure the hiding property of the adherend only by the action of the white adhesive is added to the acrylic resin. It can be dispersed uniformly.

Further, if the Tg of the acrylic resin is high, the Tg of the whole white pressure-sensitive adhesive also becomes high, and the tackiness at low temperature is lowered. This may adversely affect, for example, the workability in cold regions. If the Tg of the acrylic resin is -10 ° C or lower, such a problem does not occur.

Polymers of (meth) acrylic acid ester monomers are often used for acrylic resins having a Tg of -10 ° C. or lower, and generally (meth) acrylic acid ester of alcohol having an alkyl group having 1 to 12 carbon atoms, A (meth) acrylic acid ester having an alkyl group having 4 to 12 carbon atoms is preferably used. The (meth) acrylic acid ester means an acrylic acid ester and / or a methacrylic acid ester. Specific examples of the (meth) acrylic acid ester monomer include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate,
2-ethylhexyl acrylate, methyl methacrylate,
Examples thereof include ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, and lauryl methacrylate.

Further, as the monomer constituting the acrylic resin, acrylic acid, methacrylic acid, maleic acid, itaconic acid, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, acrylamide, N-methylol, N- Methylol acrylamide,
Examples thereof include diacetone acrylamide, glycidyl methacrylate, styrene, vinyl acetate, acrylonitrile, etc. These monomers and the above (meth) acrylic acid ester monomers are used alone or in combination for polymerization, and have a Tg of -10. It is an acrylic resin having a temperature of ℃ or less.

The white pigment used for preparing the white toner is not particularly limited as long as it does not affect the performance of the pressure-sensitive adhesive and can be colored in white. For example, titanium oxide, zinc oxide, calcium carbonate, aluminum oxide and the like can be mentioned, and titanium oxide is preferably used from the viewpoint of coloring power and hiding power. Further, in order to improve the stability, dispersibility, and weather resistance of the white pigment, the pigment may be subjected to surface treatment such as organic treatment, silicone treatment, and alumina treatment.

In the method for producing a decorative pressure-sensitive adhesive sheet of the present invention, by appropriately setting the ratio of the white pigment and the acrylic resin when producing the white toner, 3 to 100 parts by weight of the pressure-sensitive adhesive can contain 3 to 3 parts of the white pigment. A white pressure-sensitive adhesive composition containing 50 parts by weight and an acrylic resin in an amount of 10 to 150% by weight with respect to a white pigment is obtained. If the ratio of the acrylic resin is too low, the dispersibility of the white pigment and the acrylic resin will be insufficient, and if it is too high, the concentration of the acrylic resin in the adhesive will be high, which may adversely affect the adhesiveness.

To prepare a white toner by uniformly dispersing the white pigment and the above acrylic resin, for example, a method of kneading both using a roll mill, a ball mill or the like can be mentioned. The average particle size of the white toner is preferably 10 μm or less. When the average particle diameter of the white toner exceeds 10 μm, when the white toner is mixed with the pressure-sensitive adhesive to form a white pressure-sensitive adhesive, a poor appearance occurs or sufficient light diffusivity cannot be obtained due to the relationship with the thickness of the white pressure-sensitive adhesive layer. Since the surface of the adherend is insufficiently concealed, the intended decorative pressure-sensitive adhesive sheet with high saturation cannot be obtained.

As the adhesive used in the white adhesive,
It is possible to use general-purpose adhesives such as rubber-based, acrylic-based, and silicone-based adhesives. Among them, it is desirable to use an acrylic adhesive from the viewpoint of weather resistance and cost. Further, in order to further improve the weather resistance, an ultraviolet absorber may be blended in the adhesive. The number of parts to be added is preferably 1 to 6 parts by weight with respect to 100 parts by weight of the resin component of the adhesive.

As a method for producing a white pressure-sensitive adhesive composition, it is desirable to mix a white toner prepared in advance with a solvent to dilute the toner and then add the diluted toner into the pressure-sensitive adhesive solution.
If only the white toner is directly added to the pressure-sensitive adhesive, the solid content increases and the viscosity of the pressure-sensitive adhesive solution increases, which may deteriorate workability and coatability. The solvent used for dilution is preferably the same as the solvent contained in the adhesive, ethyl acetate, toluene, xylene, methyl ethyl ketone,
Aromatic, polyester, and ketone solvents such as methyl isobutyl ketone can be used. A curing agent may be added to the white pressure-sensitive adhesive composition.

The thickness of the white pressure-sensitive adhesive layer is preferably 20 to 50 μm. If it is less than 20 μm, the adhesive property and hiding property may not be sufficiently exhibited, and if it exceeds 50 μm, it is not realistic from the viewpoint of cost and productivity.

In order to obtain the above-mentioned colored film in the present invention, for example, a casting molding method obtained by casting a polyvinyl chloride sol dispersed in a solvent on the surface of the process paper, drying and curing, or a calendar molding with high productivity. The law etc. can be adopted. The thickness of this colored film is 40-1
20 μm is practically preferable. When the thickness is less than 40 μm, the sheet is too thin and the tensile strength is weakened, and the workability is likely to be adversely affected. If it exceeds 120 μm, the sheet becomes stiff, and in this case also, workability is likely to be adversely affected.

In order to form a pressure-sensitive adhesive layer on one surface of the colored film in the present invention, it is usually necessary to apply the above-mentioned pressure-sensitive adhesive composition to one surface of a high-quality paper or the like, which has been subjected to a release treatment on both surfaces. After drying and curing to form an adhesive layer, the colored film is superposed and pressed with the adhesive layer under heating at about 35 to 45 ° C., and the adhesive layer is transferred and laminated. In some cases, the pressure-sensitive adhesive composition may be directly applied onto the colored film and dried to form the pressure-sensitive adhesive layer.

(Function) In the method for producing a decorative pressure-sensitive adhesive sheet of the present invention, the Tg of the acrylic resin used for producing the toner is set to -10 ° C. or lower to increase the filling amount of the white pigment, It is possible to dramatically improve the uniform dispersibility, and only by providing the white pressure-sensitive adhesive layer,
It is possible to satisfy the sufficient covering property of the adherend.
Further, since the Tg of the entire white pressure-sensitive adhesive layer is not increased, workability in cold regions and the like can be improved.

[0027]

EXAMPLES Examples and comparative examples of the present invention will be specifically described below. The present invention is not limited to the following examples.

The colored film having a thickness of 50 μm, which was commonly used in Examples and Comparative Examples of the present invention, was prepared by the casting method by blending the following materials. Total light transmittance is 30%
Met. In the following, "parts" means "parts by weight". [Raw material blending for colored film] Vinyl chloride resin (Kanefuchi Chemical Co., PSH-10) ... 100 parts Polyester plasticizer (Asahi Denka Co., P-300)・ 30 parts yellow pigment (Dainichi Seika VT-6420) ・ ・ ・ ・ ・ ・ 4 parts Heat stabilizer (Asahi Denka MARK AR551) ・ ・ ・ ・ 5 parts UV absorber (Sumitomo Chemistry, Sumisorb 140) ..... 1 part Solvent (Exxon Chemical Co., Solvesso 100) ..... 60 parts

Example 1 White pigment (titanium oxide) 70
Parts and acrylic resin (Toagosei UP-1000, Tg
= -60 ° C, 30 parts of an acrylic copolymer using butyl acrylate as a comonomer) was mixed with a three-roll mill to prepare a white toner. 20 parts of a solvent (ethyl acetate) was kneaded with 15 parts of this toner and uniformly dispersed, and the obtained white solution was used as an acrylic pressure-sensitive adhesive (SK manufactured by Soken Chemical Co., Ltd.).
1335) It was added to 100 parts by weight and stirred with a dissolver until uniform to obtain a white pressure-sensitive adhesive composition. A curing agent (M-5A manufactured by Soken Chemical Co., Ltd.) was added to the white adhesive composition in an amount of 5
What was mixed and stirred in parts was applied to a release substrate (3) which had been subjected to a release treatment on both sides of a high-quality paper to obtain a pressure-sensitive adhesive layer having a thickness of 30 μm. 40 parts of the obtained pressure-sensitive adhesive layer and the colored film (1)
The pressure-sensitive adhesive layer is superposed on the pressure-sensitive adhesive layer under heating at a temperature of 50 ° C., and the pressure-sensitive adhesive layer is transferred and laminated to form a colored film (1) as shown in FIG.
A target adhesive pressure-sensitive adhesive sheet sample in which the white pressure-sensitive adhesive layer (2) was formed on one surface of was obtained.

(Example 2) Other than using 70 parts of a white pigment (titanium oxide) and 30 parts of an acrylic resin (UT-200 manufactured by Soken Chemical Industry Co., Ltd.) having a Tg of about -70 ° C. in producing a white toner. Was obtained in the same manner as in Example 1 to obtain a decorative adhesive sheet sample.

Comparative Example 1 A white toner was prepared by using a masterbatch in which 70 parts of a white pigment (titanium oxide) and 30 parts of an acrylic resin having a Tg of about 100 ° C. were preliminarily dispersed. In the same manner as in Example 1, a decorative adhesive sheet sample was obtained. (Comparative Example 2) 15 parts of a white pigment (titanium oxide) was used as an acrylic pressure-sensitive adhesive (SK1335 manufactured by Soken Chemical Co., Ltd.) instead of producing a white toner.
The mixture was added to 0 parts by weight, and thereafter, a decorative pressure-sensitive adhesive sheet sample was obtained in the same manner as in Example 1.

[Evaluation] The following evaluations were performed on the above samples. 1) Evaluation of dispersibility: Evaluation of dispersibility and uniformity of white pressure-sensitive adhesive solution When there is no particle having a particle gauge of 10 μm or more ◎ When there is a small proportion of particles having a particle gauge of 10 μm or more ○ Particle having a particle gauge of 10 μm or more Is high ratio x 2) Working time: Time from the start of mixing the white toner and the pressure-sensitive adhesive until it becomes uniform 20 minutes or less ○ 20 to 60 minutes △ 60 minutes or more × 3) Appearance: The surface of the pressure-sensitive adhesive sheet The appearance was visually confirmed. Judgment Appearance Good ○ Poor part △ Grain foreign matter × 4) Saturation: Visually comparing the decorative pressure-sensitive adhesive sheets obtained in each of the Examples and Comparative Examples with the colored film not having the pressure-sensitive adhesive layer formed. Then, we checked for differences. Judgment: Saturation improvement was definitely observed. ◎ Saturation improvement was slightly recognized. ○ Saturation improvement was not recognized. × 5) Concealability: For decoration obtained in each Example and Comparative Example. The pressure-sensitive adhesive sheet was placed on the white and black sheets and visually checked for differences. Judgment No difference was recognized ◎ A slight difference was recognized ○ A difference was clearly recognized ×

[0033]

[Table 1]

[0034]

The method for producing a decorative pressure-sensitive adhesive sheet of the present invention is configured as described above, and by the configuration of the white pressure-sensitive adhesive layer,
It is possible to obtain a decorative pressure-sensitive adhesive sheet having sufficient adherend concealing properties in terms of cost. Further, it is possible to provide a decorative pressure-sensitive adhesive sheet that can improve workability in cold regions and the like.

The white toner of the present invention can be used in the method for producing the decorative pressure-sensitive adhesive sheet, and can exhibit the above effects.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a decorative pressure-sensitive adhesive sheet obtained by the method for producing a decorative pressure-sensitive adhesive sheet of the present invention.

[Explanation of symbols]

1: Transparent colored film 2: White adhesive layer 3: Base material for release

Claims (2)

[Claims] 1. A white pressure-sensitive adhesive composition obtained by uniformly dispersing a white pigment and an acrylic resin having a Tg of −10 ° C. or less to prepare a white toner, and mixing the white toner and the pressure-sensitive adhesive. In one side of the colored film having a total light transmittance of 3 to 80%, the white pigment is contained in an amount of 3 to 50 parts by weight with respect to 100 parts by weight of the adhesive, and the acrylic resin is contained in an amount of 10 to 150 with respect to the white pigment. A method for producing a decorative pressure-sensitive adhesive sheet, which comprises forming a white pressure-sensitive adhesive layer that is contained by weight. 2. The white toner used in the method for producing a decorative pressure-sensitive adhesive sheet according to claim 1, wherein a white pigment and an acrylic resin having Tg of −10 ° C. or less are uniformly dispersed.