JP3039016B2 - label - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a label having heat resistance. More specifically, the present invention relates to a label having excellent heat stability.

[0002]

2. Description of the Related Art In general, paper substrates have been dominant in label substrates, but in recent years, those using film supports instead of paper supports have been spreading in various fields. In terms of surface, those using a heat-resistant base material have been actively proposed. Among them, a label using a polyphenylene sulfide film as a base material, which has extremely excellent properties such as heat resistance, chemical resistance, and mechanical properties, as a film support, has attracted attention.

[0003]

However, a label using a polyphenylene sulfide film as a support,
For example, when used in a high-temperature environment of 250 ° C. or higher, there is a disadvantage that the thermal dimensional stability is insufficient, so that the material is easily deformed on an adherend and further easily peeled off. In addition, when applied to an adherend such as a steel building material and applied, and then subjected to high-temperature baking, uncoated portions are generated around the label due to heat shrinkage of the film support, which easily causes rust. There is. That is, a label having excellent thermal dimensional stability has not been obtained.

An object of the present invention is to provide a label which is excellent in adhesion between a film support and a receiving layer and an adhesive layer, and which is excellent in thermal dimensional stability.

[0005]

The present invention has the following configuration to achieve the above object. That is, in a label in which an adhesive layer is provided on one surface of a polyphenylene sulfide film having a receiving layer on at least one surface, the polyphenylene sulfide film has a heat shrinkage at 250 ° C. of less than 5% and a surface wetting index. Is 55 dyn / cm or more.

In the present invention, a polyphenylene sulfide film (hereinafter sometimes abbreviated as a PPS film) is a biaxially oriented film of a resin composition containing poly-p-phenylene sulfide as a main component. The film is preferably a crystallized film having a crystallinity of 25% to 45% by an X-ray diffraction method. Further, the orientation degree OF determined for the crystal peak at 2θ = 20 to 21 ° C. by wide-angle X-ray diffraction is 0.07 to less in the End direction and the Edge direction.
It is preferable that the film is a biaxially oriented film in the range of 0.5 to 0.6 to 1.0 in the through direction.

Here, a resin composition containing poly-p-phenylene sulfide as a main component (hereinafter sometimes abbreviated as a PPS-based composition) is a composition containing at least 70% by weight of poly-p-phenylene sulfide. Say When the content of poly-p-phenylene sulfide is less than 70% by weight, the crystallinity and the heat transition temperature of the composition are low, and the heat resistance, dimensional stability and mechanical properties, which are characteristics of a film composed of the composition, are obtained. Etc. are impaired. The remaining less than 30% by weight of the composition may contain additives other than poly-p-phenylene sulfide, such as polymers, inorganic or organic fillers, lubricants, coloring agents, and UV absorbers. The melt viscosity of the resin composition is 500 to 12,000 poise (more preferably, 7 to 70 ° C.) at a temperature of 300 ° C. and a shear rate of 200 l / sec.
The range of (00 to 10,000 poise) is preferable from the viewpoint of film formability. The melt viscosity of the resin composition is equal to the melt viscosity of the finally obtained polyphenylene sulfide film.

In the present invention, poly-p-phenylene sulfide (hereinafter sometimes abbreviated as PPS) means that at least 70 mol% (preferably at least 85 mol%) of the repeating unit has the structural formula

[0009]

Embedded image

A polymer comprising the structural unit represented by If the content of such a component is less than 70 mol%, the crystallinity of the polymer, the thermal transition temperature, and the like will be low, and the heat resistance, dimensional stability, mechanical properties, and the like, which are characteristics of a film composed of a resin composition containing PPS as a main component, will be impaired.

If the amount of the repeating unit is less than 30 mol%, preferably less than 15 mol%, a unit containing a copolymerizable sulfide bond may be contained.

The receiving layer of the present invention is a layer composed of a composition containing a white hidden pay pigment and a polymer resin binder as main components. The layer as the main component refers to a layer which is 50% by weight or more in the receiving layer, and other substances may be appropriately added. In the present invention, such a receiving layer is provided on at least one surface of the film support. When both of the receiving layers are provided, the description of the receiving layer described below applies to at least one of them.

The polymer resin binder as referred to in the present invention is:
Thermoplastic resins, selected from thermosetting resins, resins that are soluble in well-known organic solvents, and those having less hydrophilic groups or hydrophilic components are preferred in terms of water resistance, moisture resistance, etc. of the receiving layer, Specific examples include, for example, acrylic, vinyl, urethane, epoxy, polyester, polypropylene, melamine, carbonate, butyral, etc., and copolymers and mixtures thereof.

In the present invention, the water resistance, solvent resistance,
From the viewpoint of heat resistance, abrasion resistance, mechanical strength, and the like, it is preferable to use a thermosetting resin, and more preferably, a resin which can be crosslinked by using a well-known crosslinking agent. In addition, examples of the organic solvent include, for example, alcohols, carboxylate esters, ketones, aliphatic hydrocarbons, alicyclic or aromatic hydrocarbons, and mixtures thereof, and do not adversely affect coating properties and the like. The choice of one is preferred.

The white hidden pay pigment referred to in the present invention is an inorganic or organic pigment that exhibits a white receiving layer. Examples of the inorganic pigment include zinc carbonate, zinc oxide, zinc sulfide, and the like.
Talc, kaolin, heavy / light or synthetic calcium carbonate, titanium oxide, silica, lithium fluoride, calcium fluoride, barium sulfate, alumina, zirconia, calcium phosphate, natural or synthetic swellable or non-swellable mica, etc. Examples of organic pigments include, for example, polystyrene, polymethylstyrene, polymethoxystyrene, polyvinyl chloride, polyethylene, polypropylene, polyvinylidene chloride, polymethacrylate, polymethylmethacrylate, polychloroacrylate, and the like. At least one kind selected from the following is applied, but is not particularly limited. The pigment may be in a hollow porous or non-hollow porous state. Further, the pigment may be subjected to a treatment such as adding a functional group such as glycidyl or methylol group to the surface in order to improve dispersibility in the resin.

The average particle size of the white hidden pay pigment is 0.1 to 25.
μm, preferably in the range of 1.0 to 10 μm, is preferred in terms of handleability, coatability and the like. Further, the content of the white hidden pay pigment in the receiving layer is preferably 0.1 to 70% by weight, more preferably 5 to 50% by weight. Content is 0.
If the amount is less than 1% by weight, the white concealing payability becomes insufficient, and if the amount is 70% by weight or more, the adhesion between the receiving layer and the film substrate tends to be reduced.

In the present invention, the adhesiveness of the receiving layer, the solvent resistance,
In order to further improve the heat resistance, it is preferable that the receiving layer contains a crosslinking agent.

The cross-linking agent referred to in the present invention is a functional group present in a polymer resin binder, for example, a hydroxyl group,
It is not particularly limited as long as it is a cross-linking agent for performing a cross-linking reaction with a carboxyl group, a glycidyl group, an amide group, etc., and finally as a receiving layer having a three-dimensional network structure. Examples include urea-based, melamine-based, acrylamide-based, and polyamide-based resins, and epoxy compounds, isocyanate compounds, and aziridine compounds.

These crosslinking agents may be used alone or in combination of two or more. The amount of the cross-linking agent to be added is appropriately selected depending on the type of the cross-linking agent, but is usually preferably 0.01 to 50 parts by weight, more preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the solid content of the polymer resin. preferable. Further, it is more preferable to use a crosslinking catalyst in combination with the crosslinking binder because crosslinking proceeds more. Known catalysts such as salts, inorganic substances, organic substances, acid substances, and alkaline substances can be used as the crosslinking catalyst. The amount of the crosslinking catalyst to be added is 0.001 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the solid content of the polymer resin. The polymer resin to which the cross-linking agent is added is cross-linked by heating, ultraviolet rays, electron beams or the like after being applied to the film support, but a method by heating is generally used.

The adhesive layer in the present invention is not particularly limited. (1) Polymers such as natural rubber, styrene / butadiene rubber, polyisobutylene, polychloroprene, polyacrylate rubber and polyvinyl ether rubber;
(2) Polyvinyl chloride, a copolymer of vinyl chloride and vinyl acetate, polyvinyl butyral, chlorinated rubber, hydrochloride rubber, a mixture of a polymer material such as polyacrylate and its copolymer, and a plasticizer, (3 ) Rosin, rosin ester,
Tackifiers such as coumarone resin, terpene resin, hydrocarbon resin, oil-soluble phenol resin, (4) fillers, pigments,
Various additives such as anti-aging agents, stabilizers, etc. (1) ~
Various combinations of (4) and silicone-based pressure-sensitive adhesives can be mentioned as typical examples.

The PPS film constituting the label of the present invention must have a heat shrinkage of less than 5%, preferably less than 3% at 250 ° C. in both the longitudinal and width directions. When the heat shrinkage is 5% or more, the label has poor thermal dimensional stability, and is easily deformed at high temperatures or easily peeled off from the adherend, which is not preferable. In particular, the heat shrinkage at 250 ° C. is often important. Further, in the present invention, PP
It is necessary that the surface wetting index of the S film is 55 dyn / cm or more. Preferably it is 60 dyn / cm or more. When the surface wetting index is less than 55 dyn / cm, the adhesion between the receiving layer and the adhesive layer is insufficient, and it is difficult to obtain a label having heat resistance and durability. Although the thickness of the PPS film is not particularly limited, it is preferably 10 to 500 μm, and more preferably 25 to 300 μm.
Is more preferable and the handleability in practical use as a substrate base is excellent. The surface roughness, optical haze, and the like of the PPS film are not particularly limited, and may be desired.

It is desirable that the receiving layer constituting the label of the present invention has a smoothness of from 2 to 3000 seconds, preferably from 10 to 1500 seconds. When the smoothness is out of this range, for example, when printing is performed using a fabric ribbon, the ink permeability does not match, the printing becomes lighter, and the ink tends to remain on the surface of the receiving layer. In the present invention, the hunter whiteness of the receiving layer is 40% or more,
Preferably, it is 60% or more. If the Hunter whiteness is less than 40%, the hidden payability becomes insufficient, and the resolution and sharpness of printing are reduced, and reading errors such as in the case of bar codes are liable to occur, which is not preferable.
The layer thickness of the receiving layer is not particularly limited, but is preferably 0.5 to 50 μm, and preferably in the range of 1.0 to 20 μm in terms of uniformity of the receiving layer, adhesion and the like. In addition, if necessary, known additives such as antifoaming agents, coating improvers, thickeners, antistatic agents, antioxidants, and ultraviolet absorbers may be added to the receiving layer in amounts that do not impair the effects of the present invention. Agent,
A dye or the like may be contained.

The thickness of the pressure-sensitive adhesive layer constituting the label of the present invention is not particularly limited to a thickness of 1.0 to 100 μm.
m, preferably in the range of 5.0 to 50 μm, in terms of uniform formability, adhesive strength and the like. If necessary, a release layer may be further provided on the adhesive layer side, or a substrate having a release property may be laminated on the adhesive layer side before use.

Next, a method for producing a label of the present invention will be described. However, it is not limited to this.

First, the PPS film is melt-extruded from a die with an extruder by an extruder, cast into a sheet, and if necessary, stretched and heat-treated by a known method to obtain a biaxially stretched film. After winding the obtained biaxially stretched film in the film forming process or as a single film base film,
Further, at a temperature below the melting point, preferably at 150 to 250 ° C, 1
Relax for seconds to 60 minutes.

Next, after a receiving layer is provided on at least one surface of the film, an adhesive layer is provided on one surface. Usually, a receiving layer is provided on one surface and an adhesive layer is provided on the other surface. As a method for providing the receiving layer and the adhesive layer, a coating agent adjusted to a predetermined amount in a film forming process is applied, and then dried, or wound up as a base film single film, followed by a coating-drying process. Is preferably applied. The coating method is not particularly limited, and a known method such as a gravure coating method, a reverse coating method, a kiss coating method, a die coating method, a metaling bar coating method, and a knife coating method can be applied. In addition, by applying a known surface treatment such as a corona discharge treatment in the air or in various other atmospheres before coating, not only the coating properties are improved, but also each layer is more firmly applied to the substrate. Can be formed on a surface. The concentration of the coating material and the conditions for drying the coating film are not particularly limited, but the drying conditions for the coating film are desirably performed within a range that does not adversely affect the properties of the base film.

[0027]

[Evaluation method] The characteristic values of the present invention are based on the following measuring methods and evaluation criteria.

(1) Adhesiveness of Receptive Layer The adhesiveness of the receiving layer / film support was measured by inserting a cross cut (100 pieces / cm ² ) on the receiving layer and making a cellophane tape (CT) at 45 ° to the cross cut surface. -24 (Nichiban Co., Ltd.)
Product) and apply 10kg with a load of about 5kg using a hand roller.
The cellophane tape was forcibly peeled in the direction of 180 ° by hand, and the degree of peeling of the receiving layer was observed and evaluated. The criteria were: ○: very good (no peeling), Δ: slightly inferior (less than 20% peeled area), ×: poor (20% or more peeled area).

(2) Smoothness Smoothness was measured by an Oken type air permeability smoothing tester “Model KB15” (Asahi Seiko Co., Ltd.).

(3) Hunter whiteness Using a Macbeth 2000 manufactured by Kolmorgen, L
a and b were measured, and Hunter whiteness (W) was calculated by the following formula (measured at 550 nm). W = 100 [(100−L) ² + a ² + b ² ] ^1/2

(4) Heat shrinkage The film is 10 mm wide and 300 mm long in the longitudinal or width direction.
And fixed to the support plate under constant tension (5 g), and then the original length a (m
m). Next, a load was applied using a 3 g clip and the coating was treated for 10 minutes while rotating in a hot air oven at 250 ° C., and the marking interval b (m
m). The heat shrinkage is determined by the following equation, and the average value of five pieces is used. Heat shrinkage (%) = (ab) / a

(5) Recordability Serial printer “PC-PR20” manufactured by NEC Corporation
1U ", and the character pattern is changed to the fabric ribbon" O
AR-NF-2 "(manufactured by Pilot Co., Ltd.), and the print quality and ink absorbability were evaluated, and the recordability was determined as follows.The print quality was evaluated by visual observation, and the ink absorption was evaluated. Immediately after printing, the character pattern was rubbed back and forth five times with a finger, and evaluated by the degree of smearing of the ink receiving layer by the ink: ○: Both print quality and ink absorbency were good Δ: Print quality and ink absorbency were slightly inferior ×: Both print quality and ink absorbency are poor

(6) Thermal stability The label was attached to the surface of a degreased clean SUS304 plate, pressed and reciprocated once with a hand roller having a load of 2 kg, and then heat-treated at 250 ° C. for 60 minutes to change the appearance of the label. Was observed and judged as follows. ：: no change in appearance △: slight shrinkage deformation observed ×: remarkable shrinkage deformation

(7) Surface Wetting Index The surface wetting index was measured based on JIS-K-6768 to determine the wetting index.

[0035]

According to the present invention, since the receiving layer and the adhesive layer are formed on the surface of the PPS film having specific characteristics, the following excellent effects can be obtained.

(1) Since the label has excellent thermal dimensional stability, it has sufficient durability even in a high temperature environment. (2) The label has excellent handleability since it has excellent adhesion between the receiving layer and the adhesive layer. (3) The label receiving layer is excellent in printability with various inks such as a thermal transfer ink ribbon, a fabric ribbon, an electrophotographic toner, and an oil-based ink.

[0037]

Uses of the product of the present invention The use of the label of the present invention is not particularly limited. For example, display labels for name, price, quality, etc., various stickers, for cans, for surface protection, for cutting paper and film, etc. Widely adaptable. Among them, it is particularly useful for bar code labels, display labels, and the like that are applied to the manufacturing process, quality control, and the like of products particularly in a high-temperature region.

[0038]

The present invention will be described with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

Example 1 A PPS film having a thickness of 38 μm and a heat shrinkage at 250 ° C. of 13/11 (%) in a longitudinal direction / width direction = 10 ° C. at 220 ° C.
After annealing treatment for two minutes, both surfaces of the film were subjected to corona discharge treatment. The film thus obtained had a heat shrinkage of 2.3 / 1.9 (%) in the longitudinal direction / width direction and a surface wetting index of 68 dyn / cm.

Next, toluene / ethyl acetate (mixing ratio;
1: 1) as a diluting solvent, and heat-crosslinkable acrylic resin “KOTAX” LH-613 (manufactured by Toray Industries, Inc.) and titanium oxide having an average particle size of 1.0 μm as a white concealed pay pigment were added to a solid content of 40 μm. A 25% by weight of a uniformly dispersed coating material having a concentration of 25% by weight is applied on one surface of the film by a gravure coating method, and the applied layer is dried at 120 ° C. for 1 minute to provide a receiving layer having a thickness of 3.0 μm. Was. Further, on the opposite side of the receiving layer, a silicone adhesive "SH4570" having a concentration of 30% by weight using toluene as a diluting solvent (Tore Dow Corning Co., Ltd.)
Co., Ltd.) is applied by a gravure coat method,
For 1 minute to provide an adhesive layer having a thickness of 20 μm, and a label was obtained by overlapping with a commercially available release film. The properties of the label were as shown in Table 1 and were excellent in recording properties and thermal stability.

Comparative Examples 1 and 2 Based on Example 1, a PPS film having a thickness of 38 μm and a heat shrinkage ratio of 13/11 (%) in the longitudinal direction / width direction (Comparative Example 1) and annealing conditions were changed. A label was obtained by the same method except that a PPS film (Comparative Example 2) having an obtained heat shrinkage of 7.9 / 6.5 (%) in the longitudinal direction / width direction was used. The label characteristics were as shown in Table 1 and the thermal stability was insufficient.

Comparative Examples 3 and 4 Based on Example 1, the same PPS film as in Example 1 was used, and the surface wetting index was changed by changing the corona treatment strength. As shown in Table 1, the label characteristics were insufficient adhesion of the receiving layer, and it was found that the durability was uneasy.

Example 2 The same PPS film as in Example 1 was used, and titanium oxide having an average particle size of 0.5 μm was used as a white opaque pigment in the same polymer resin binder as in Example 1 in an amount of 30% by weight based on the solid content. 1 μm of porous amorphous silica having a particle size of 4.0 μm per solid content
A label was obtained in the same manner as in Example 1 using a uniformly dispersed coating material having a concentration of 30% by weight to which 0% by weight was added. As shown in Table 1, each of the label characteristics was excellent.

[0044]

[Table 1]

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-65784 (JP, A) JP-A-4-67087 (JP, A) JP-A-3-136847 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G09F 3/00-3/20 B32B 1/00-35/00 C08J 5/18

Claims (3)

(57) [Claims] 1. A label having an adhesive layer on one surface of a polyphenylene sulfide film having a receptor layer on at least one surface, wherein the polyphenylene sulfide film has a heat shrinkage of less than 5% at 250 ° C. A label having a wetting index of 55 dyn / cm or more. 2. The label according to claim 1, wherein the smoothness of the receiving layer is from 2 to 3000 seconds. 3. The label according to claim 1, wherein the hunter whiteness of the receiving layer is 40% or more.