JPH09255925A - Method for winding thermally pressure-sensitive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for winding up a thermally pressure-sensitive sheet without causing blocking or winding slippage. SOLUTION: The method comprises winding up a thermally pressure-sensitive sheet which is nontacky at ordinary temps. but becomes tacky upon heating under the conditions under with the winding index(WI) defined by the equation is 15-60. In the equation, μs is the static coefficient of friction in the widthwise direction of superposed layers in a roll of the sheet (in accordance with the horizontal method of JIS P-8147); T is tension for winding, D is the diameter of the final roll; D0 is core diameter; Z is the thickness of the sheet; and Y is the width of the sheet wound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for winding a heat-sensitive adhesive sheet which is non-adhesive at room temperature but exhibits adhesiveness when heated.

[0002]

2. Description of the Related Art Generally, a heat-sensitive adhesive sheet has a structure in which a heat-sensitive adhesive is applied on one side of a substrate, and is usually used as a label by printing on the other side of the substrate. The heat-sensitive adhesive is non-adhesive at room temperature, but is activated and develops adhesiveness when heated with a labeler or an oven provided with a heating device. Usually, the activation temperature is 50 to 150 ° C. In this temperature range, the thermoplastic resin is plasticized to give adhesiveness to the label. There is.

However, the heat-sensitive adhesive sheet is often stored in a wound state, and in this case, if the storage temperature is higher than room temperature or the winding pressure is too strong, blocking occurs. is there.

In order to solve this problem, for example, a method of weakening the winding pressure of the winding can be considered. However, if the winding pressure is excessively weakened, the heat-sensitive adhesive sheets that overlap each other inside the winding cause side slip, Since the winding deviation easily occurs, a new problem that the handling becomes very difficult occurs.

In addition, a method of adding or mixing an inorganic substance in a heat-sensitive adhesive as an anti-blocking agent (Japanese Patent Laid-Open No. 2-282050), or an inorganic compound or colloidal particles on the surface of a solid plasticizer in the heat-sensitive adhesive And blocking by preventing softening of the solid plasticizer (JP-A-6-57223 and JP-A-6-10084).
No. 7, JP-A-6-100848) and the like are proposed.

However, the blocking resistance is not sufficient by simply adding an ordinary inorganic substance. Further, when the solid plasticizer is protected by an inorganic compound or colloidal particles, when the heat-sensitive adhesive is heated to a temperature of 80 ° C. or lower to be activated,
It takes a long time to melt and diffuse the solid plasticizer, and the adhesiveness of the heat-sensitive adhesive hardly appears, and the adhesive function of the heat-sensitive adhesive sheet is deteriorated.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method for winding a heat-sensitive adhesive sheet so as to prevent blocking and winding deviation.

[0008]

Means for Solving the Problems As a result of intensive studies on the winding method of the heat-sensitive adhesive sheet, the present inventors have found that
It has been found that by winding so that the winding index WI value defined by the following formula falls within a specific range, winding deviation is less likely to occur and excellent blocking can be achieved. . That is, according to the present invention, in a heat-sensitive adhesive sheet that is non-adhesive at room temperature, but exhibits adhesiveness by heating, the winding index WI value defined by the following formula is in the range of 15 to 60. It is a method for winding a heat-sensitive adhesive sheet, which is characterized in that

(Equation 3) In the formula, μ _S : coefficient of static friction in the width direction between heat-sensitive adhesive sheets that overlap each other inside the winding (according to JIS P-8147 horizontal method), T: tension during winding, D: final winding diameter, D ₀ : winding core diameter, Z: thickness of heat-sensitive adhesive sheet,
Y: Shows the winding width. . It is a method for winding a heat-sensitive adhesive sheet, wherein the winding index WI value is in the range of 23 to 37. . It is a method for winding a heat-sensitive adhesive sheet having a static friction coefficient μ _S value of 0.5 or more. . A method for winding a heat-sensitive adhesive sheet, characterized in that the tension T is obtained by the following formula when obtaining the described winding index WI value.

(Equation 4) In the equation, the tension is changed from T ₁ to T _n during winding.
D: final winding diameter, D ₀ : winding core diameter, D _X : winding diameter after winding with tension T _X when changing as described above.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-sensitive adhesive sheet as used in the present invention is a sheet-shaped substrate on which a heat-sensitive adhesive is applied and dried. Many heat-sensitive adhesives mainly consist of a thermoplastic resin, a solid plasticizer, a tackifier, etc., and their forms include emulsion type, organic solvent type, solventless type and the like. In addition, it is generally classified into hot melt type adhesives, heat seal type adhesives, delayed tack type adhesives, etc. from the time until the adhesiveness generated by heat activation of the heat sensitive adhesive disappears after removing the heat source. Has been done. Among them, the emulsion-type delayed tack adhesive is preferably applied to one surface of the substrate and dried, but the present invention is not limited to this.

The types of thermoplastic resins used in the heat-sensitive adhesive include vinyl acetate-ethylene-styrene copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-ethylene-vinyl chloride copolymer, vinyl acetate. -Acrylic acid ester copolymer, vinyl acetate-ethylene-acrylic acid ester copolymer, ethylene-vinyl chloride copolymer, (meth) acrylic acid ester copolymer, styrene-isoprene copolymer, styrene-butadiene copolymer Examples thereof include coalesce and acrylonitrile-butadiene copolymer. These thermoplastic resins are used alone or in combination.

The glass transition temperature of the thermoplastic resin is in the range of -35 to 80 ° C, more preferably-.
It is 10-70 degreeC. If the glass transition temperature of the thermoplastic resin is lower than -35 ° C, the thermoplastic resin has tackiness even at room temperature, resulting in poor blocking resistance. On the other hand, when the temperature exceeds 80 ° C., when applied as a heat-sensitive adhesive to a substrate, the surface strength of the surface coated with the heat-sensitive adhesive becomes weak and the printability becomes poor when used as a label.

The types of solid plasticizers used in heat-sensitive adhesives include dihexyl phthalate (melting point 65 ° C.), dicyclohexyl phthalate (melting point 63 to 65 ° C.), dihydroabietyl phthalate (melting point 65 ° C.), Dimethyl isophthalate (melting point 66-67 ° C), N-cyclohexyl-p-
Toluenesulfonamide (melting point 86 ° C), sucrose benzoate (melting point 98 ° C), ethylene glycol dibenzoate (melting point 70 ° C), trimethylolethane tribenzoate (melting point 73 ° C), pentaerythritol tetrabenzoate (melting point 95).
), Sucrose octaacetate (melting point 89 ° C), tricyclohexyl citrate (melting point 57 ° C), etc.
It is preferable to use By the way, the melting point is 50 ° C.
If it is less than 100 ° C., the blocking resistance is poor, and if it exceeds 100 ° C., it is difficult to activate by heating. The solid plasticizer melts at a temperature equal to or higher than the melting point when activated by heating to plasticize the thermoplastic resin, and thus provides tackiness as a heat-sensitive adhesive, but the duration of tackiness varies depending on the solid plasticizer. It is preferable to use dicyclohexyl phthalate when the stickiness is prolonged. The solid plasticizers may be used alone or in combination of two or more.

Further, as the heat-sensitive adhesive, in addition to the thermoplastic resin and the solid plasticizer, a rosin-based tackifier, a phenol resin-based tackifier, a terpene resin-based tackifier,
The adhesion function may be adjusted by adding a tackifier such as a xylene-based tackifier or a petroleum resin-based tackifier, or by adding ink or the like to the heat-sensitive adhesive layer to color the heat-sensitive adhesive. Alternatively, a heat-expandable microsphere may be contained to adjust the adhesive function.

The coating amount of the heat-sensitive adhesive is preferably 5 to 30 g / m ^{2 in} dry weight. More preferably 10
Is about 20 g / m ² . Incidentally, when the coating amount is less than 5 g / m ² , there is a problem that when used as a label, a sufficient adhesive function cannot be obtained and the label cannot be used. On the other hand, if it exceeds 30 g / m ² , it takes time to heat and activate the heat-sensitive adhesive, and the adhesive function is saturated, resulting in poor economy.

The method for applying the heat-sensitive adhesive on the substrate is brush coating, spray coating, screen printing, gravure printing, offset printing, letterpress printing, Meyer bar coater, kiss roll coater, lip coater, direct roll coater. , An offset roll coater, a gravure roll coater, a reverse roll coater, a rod coater, a blade coater, an air knife coater, and the like. The drying can be carried out by a conventional method combined with the above-mentioned device for coating.

Examples of the material of the base material used in the heat-sensitive adhesive sheet of the present invention include papers, synthetic papers, films, metal foils, non-woven fabrics, woven fabrics, and sheets in which these are appropriately laminated. . Needless to say, various layers such as a heat-sensitive recording layer, a pressure-sensitive recording layer, a thermal transfer image-receiving layer, an inkjet recording layer, and a pigment coating layer may be provided on the surface of these base materials. On the other hand, the surface to which the heat-sensitive adhesive is applied may be provided with a barrier layer to reinforce the strength or prevent the heat-sensitive adhesive from penetrating into the substrate and deteriorating the adhesive function.
When used as a label, printability and the like are required. In particular, when used as a label to be attached to a glass bottle containing a liquid such as soft drink, alcoholic beverage, and chemical bottle, it is preferable to use a substrate having excellent water resistance.

The heat-sensitive adhesive sheet thus prepared is usually wound up after coating and drying the heat-sensitive adhesive,
In many cases, it is stored as it is, or if necessary, it is cut and stored in small rolls. In addition, the heat-sensitive adhesive sheet may be stored after being rewound after printing or the like. However, depending on the storage condition, problems such as blocking of winding and winding deviation occur easily.

In order to solve such a problem, the present invention conducts a detailed research, investigation and analysis on the conditions for making the winding and the easiness of winding misalignment.

(Equation 5) (In the formula, μ _S : coefficient of static friction in the width direction between heat-sensitive adhesive sheets that overlap each other inside the winding (according to JIS P-8147 horizontal method), T: tension during winding, D: final winding diameter, D ₀ : winding core diameter, Z: thickness of heat-sensitive adhesive sheet,
Y: Shows the winding width. By winding so that the winding index WI value represented by (4) is in the range of 10 to 55, preferably 18 to 32, winding deviation is less likely to occur and it is possible to achieve winding excellent in blocking. I found that.

By the way, if the WI value is less than 18, winding misalignment may occur, so care must be taken in handling the winding, and if it is less than 10, handling of the winding becomes very difficult. On the other hand, if the WI value exceeds 32, the winding may cause blocking, and if the WI value exceeds 55, the winding may cause blocking at room temperature or higher. Therefore, storage at low temperature is required.

The static friction coefficient μ _S value (in accordance with JIS P-8147 horizontal method) of the heat-sensitive adhesive sheet inside the winding is usually in the range of 0.3 to 0.6,
Although it is difficult to set the value outside this range, if the μ _S value is high, winding deviation is unlikely to occur even if the winding pressure is low. Therefore, the μ _S value of 0.5 or more is particularly preferable. To set the coefficient of static friction μ _S to 0.5 or more, for example, a material having a large friction coefficient of the base material or a method of adjusting the smoothness of the heat-sensitive adhesive coated surface can be used.

In the present invention, the tension T when obtaining the WI value may change during winding. When the tension is changed from T ₁ to T _{n in} n ways during winding,

(Equation 6) (D: final winding diameter, D ₀ : winding core diameter, D _X : tension T
_The tension T may be obtained by the formula represented by ( _X is the winding diameter after winding).

[0022]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, "parts by weight" means "parts by weight of solid" unless otherwise specified.

[Preparation of heat-sensitive adhesive sheet] [Preparation of heat-sensitive adhesive sheet (A)] As a thermoplastic resin, an ethylene-vinyl chloride copolymer having a glass transition temperature of 20 ° C (trade name "Sumieryte 1210", Sumitomo (Chemical Industry Co., Ltd.) 25 parts by weight, and a solid content concentration of 5 parts by weight of an aqueous dispersion of dicyclohexyl phthalate (melting point 64.7 ° C., Osaka Organic Chemical Industry Co., Ltd.) as a solid plasticizer 5
A 0% heat sensitive adhesive emulsion was prepared. Using a reverse roll coater on one side of a double-sided coated paper of 81.4 g / m ² (trade name “New Age”, manufactured by Shin Oji Paper Co., Ltd.), a dry weight of 15 g / m ² was obtained. After coating and drying, the heat-sensitive adhesive sheet (A) was wound up. The coefficient of static friction μ _S between the coated surface of the heat-sensitive adhesive sheet and the surface coated with the heat-sensitive adhesive was 0.56,
The paper thickness was 98 μm.

[Preparation of heat-sensitive adhesive sheet (B)] A heat-sensitive adhesive emulsion having a solid content concentration of 53% (trade name "Heat Magic DW2000", manufactured by Toyo Ink Mfg. Co., Ltd.) was used in an amount of 84.9 g / m 2. ² single-sided cast paper (trade name "Mirror Coat Gold", manufactured by Shin Oji Paper Co., Ltd.)
The surface of the base paper was coated with an air knife coater so that the dry weight was 18 g / m ^2, and dried to obtain a heat-sensitive adhesive sheet (B). The coefficient of static friction μ _S between the cast paper surface and the heat-sensitive adhesive-coated surface of this heat-sensitive adhesive sheet was 0.51, and the paper thickness was 122 μm.

[Preparation of heat-sensitive adhesive sheet (C)] A heat-sensitive adhesive emulsion having a solid content concentration of 53% (trade name "Heat Magic DW1040", manufactured by Toyo Ink Mfg. Co., Ltd.) was used in an amount of 84.9 g / m 2. ^The heat-sensitive adhesive sheet ( ²⁾ is coated on a single-sided art paper (trade name "Kinto single-sided", manufactured by Shin-Oji Paper Co., Ltd.) using a bar coater so that the dry weight is 12 g / m ² and dried. The winding of C) was obtained. The coefficient of static friction μ _S between the art paper surface and the heat-sensitive adhesive-coated surface of this heat-sensitive adhesive sheet was 0.39, and the paper thickness was 79 μm.

Example 1 The heat-sensitive adhesive sheet (A) was cut and rewound under the following conditions to prepare a roll for storage. Winding core diameter: 89mm Winding width: 200mm Tension: 75N Winding diameter: 600mm

Example 2 The heat-sensitive adhesive sheet (A) was cut and rewound under the following conditions to prepare a roll for storage. Winding core diameter: 89mm Winding width: 40mm Tension: 20N Winding diameter: 320mm

Example 3 Thermosensitive adhesive sheet (A) prepared under the following winding conditions
It was taken as it was for storage without cutting it. Winding core diameter: 215mm Winding width: 1050mm Tension: 130N Winding diameter: 1450mm

Example 4 The heat-sensitive adhesive sheet (A) was cut and rewound under the following conditions to prepare a winding for storage (tension was changed on the way). Winding core diameter: 117mm Winding width: 650mm Tension (before change): 150N Midway winding diameter: 1020mm Tension (after change): 75N Final winding diameter: 1480mm

Example 5 The heat-sensitive adhesive sheet (B) was cut and rewound under the same conditions as in Example 1 to prepare a roll for storage.

Example 6 The heat-sensitive adhesive sheet (C) was cut and rewound under the same conditions as in Example 1 to prepare a roll for storage.

Example 7 The heat-sensitive adhesive sheet (B) was cut and rewound under the same conditions as in Example 2 to prepare a roll for storage.

Example 8 The heat-sensitive adhesive sheet (B) was cut and rewound under the following conditions to prepare a roll for storage. Winding core diameter: 89mm Winding width: 40mm Tension: 50N Winding diameter: 320mm

Comparative Example 1 The heat-sensitive adhesive sheet (A) was cut and rewound under the following conditions to prepare a roll for storage. Winding core diameter: 89mm Winding width: 40mm Tension: 10N Winding diameter: 320mm

Comparative Example 2 The heat-sensitive adhesive sheet (A) was cut and rewound under the following conditions to prepare a roll for storage. Winding core diameter: 89mm Winding width: 40mm Tension: 50N Winding diameter: 320mm

Comparative Example 3 Heat-sensitive adhesive sheet (A) prepared under the following winding conditions:
It was taken as it was for storage without cutting it. Winding core diameter: 215 mm Winding width: 1050 mm Tension: 400 N Winding diameter: 1450 mm

Comparative Example 4 The heat-sensitive adhesive sheet (A) was cut and rewound under the following conditions to prepare a roll for storage. Winding core diameter: 89mm Winding width: 200mm Tension: 20N Winding diameter: 600mm

"Evaluation" Regarding the winding of the obtained heat-sensitive adhesive sheet, the easiness of blocking and winding deviation was evaluated, and the results are shown in Table 1.

[Blocking] Winding of the heat-sensitive adhesive sheet was treated at 45 ° C. for 7 days to evaluate the occurrence of blocking. ⊚: Very good with no blocking. ◯: A little blocking occurs, but there is no practical problem. Δ: There is a problem in practical use because of blocking. X: Severe blocking, which is not practical.

[Rolling Deviation] Winding of the heat-sensitive adhesive sheet was actually moved and transported to evaluate the occurrence of winding deviation. ⊚: In normal handling, winding does not occur at all. ◯: If handled carefully, there is almost no winding deviation and there is no practical problem. Δ: If it is not handled very carefully, winding will be misaligned, which is a practical problem. X: The winding misalignment is so great that it cannot be put to practical use.

[0041]

[Table 1]

[0042]

As is clear from the results shown in Table 1, in the method for winding a heat-sensitive adhesive sheet of the present invention, it is possible to prepare a winding in which winding deviation is less likely to occur and blocking is less likely to occur.

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[Procedure amendment]

[Submission date] September 24, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

In order to solve such a problem, the present invention conducts a detailed research, investigation and analysis on the conditions for making the winding and the easiness of winding misalignment.

(Equation 5) (In the formula, μ _S : coefficient of static friction in the width direction between heat-sensitive adhesive sheets that overlap each other inside the winding (according to JIS P-8147 horizontal method), T: tension during winding, D: final winding diameter, D ₀ : winding core diameter, Z: thickness of heat-sensitive adhesive sheet,
Y: Shows the winding width. By winding so that the winding index WI value represented by) is in the range of 15 to 60, preferably 23 to 37, winding deviation is less likely to occur and it is possible to achieve winding excellent in blocking. I found that.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

By the way, if the WI value is less than 23, winding misalignment may occur, so that care must be taken in handling the winding, and if it is less than 15, handling of the winding becomes very difficult. On the contrary, if the WI value exceeds 37, the winding may be blocked, and if the WI value exceeds 60, the winding may be blocked at room temperature or higher. Therefore, storage at low temperature is required.

Claims (4)

[Claims] 1. A heat-sensitive adhesive sheet which is non-adhesive at room temperature, but exhibits adhesiveness when heated, and has a winding index WI value defined by the following formula of 15 to 15.
A method for winding up a heat-sensitive adhesive sheet, which comprises winding up to 60. [Equation 1] In the formula, μ _S : coefficient of static friction in the width direction between heat-sensitive adhesive sheets that overlap each other inside the winding (according to JIS P-8147 horizontal method), T: tension during winding, D: final winding diameter, D ₀ : winding core diameter, Z: thickness of heat-sensitive adhesive sheet,
Y: Shows the winding width. 2. A winding index WI value of 23 to 37.
The method for winding up the heat-sensitive adhesive sheet according to claim 1, wherein 3. The method for winding a heat-sensitive adhesive sheet according to claim 1, wherein the static friction coefficient μ _S value is 0.5 or more. 4. The winding index WI according to claim 1.
A winding method for a heat-sensitive adhesive sheet, characterized in that the tension T is obtained by the following formula when obtaining the value. [Equation 2] In the equation, the tension is changed from T ₁ to T _n during winding.
D: final winding diameter, D ₀ : winding core diameter, D _X : winding diameter after winding with tension T _X when changing as described above.