JPH09305117A - Delayed tack type tacky adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a delayed tack type tacky adhesive sheet for ink jet recording having durability and water resistance on a printing surface. SOLUTION: The same surface as the surface provided with an ink receptive layer of the ink jet recording sheet provided with the ink receptive layer on at least one surface on a base material is provided with the delayed tack type tacky adhesive layer consisting of a solid plasticizer, tacky adhesive and tackifier. The purposes are achieved even in the case of the constitution obtd. by laminating the ink receptive layer and the delayed tack layer in this order on the base material or in the case of the constitution obtd. by forming the components described above as a single layer. The case of the lamination has preferably the constitution obtd. by incorporating inorg. pigments into the delayed tack layer. The inorg. pigments of colloidal silica are more adequate in both terms of adhesive power and ink absorptivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a delayed tack type pressure-sensitive adhesive sheet in which ink jet recording suitability and delayed tack characteristics are provided on the same surface of a substrate such as paper or film. The delayed tack type pressure-sensitive adhesive sheet of the present invention exhibits tackiness after being printed on the tack surface for a short period of time by being exposed to a heat source such as a heater or a hot air burner, and then tacked on cans, bottles, boxes, etc. which are packaging materials for products. It can be attached as a label. Further, the present invention relates to an adhesive sheet which has an advantage that unnecessary dust is not generated because a release paper is not required.

[0002]

2. Description of the Related Art Conventionally, paper coated with an ink receiving layer,
When characters, symbols, patterns, etc. are printed on a base material such as a film and then attached to an article, the back surface of the base material is permanently tacked and a release paper is temporarily attached, or a delayed tack type adhesive material. A delayed tack type adhesive sheet coated with is used. The delayed tack type pressure-sensitive adhesive sheet has a feature that it is non-tacky at room temperature, but develops tackiness by heating, and maintains tackiness for a while even if it is not heated thereafter.

As a delayed tack type adhesive sheet for ink jet recording, a sheet in which a delayed tack layer is provided on one surface of a substrate and ink jet suitability is provided on the opposite surface is reported in Japanese Utility Model Publication No. 6-50221.
However, the printed surface is always exposed to the surface, which causes problems in durability and water resistance. After printing on such a sheet, it is possible to adhere another transparent film to protect the printed surface, but this is not preferable because the work process becomes complicated.

A pressure-sensitive adhesive label obtained by imparting inkjet suitability to a pressure-sensitive adhesive sheet having room temperature is disclosed in JP-A-8-30.
No. 198 is reported. However, with this configuration, when printing with an inkjet printer, handling becomes complicated because the printing surface has adhesiveness. Further, it is necessary to temporarily attach release paper when the above-mentioned sheet is stored, which is inferior in workability and productivity when it is automatically applied as a label to an article, a product, etc. on a factory site line, and a release paper is required. As a result, the cost increases, and problems such as discarding the release paper after use occur.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the quality of the printing surface can be maintained for a long period of time by protecting the printing surface from the outside air and moisture without complicating the working process. Provided is a delayed tack type pressure-sensitive adhesive sheet which is non-adhesive at room temperature but has an inkjet suitability that develops adhesiveness when heated.

[0006]

An object of the present invention is to provide an ink receiving layer on at least one side of a base material, and a solid plasticizer, a pressure sensitive adhesive, and a tackifier on the same side as the surface on which the ink receiving layer is provided. The solution was to provide a delayed tack layer containing the agent.

The delayed tack type pressure-sensitive adhesive sheet of the present invention preferably has a constitution in which an ink receiving layer and a delayed tack layer are laminated in this order on a substrate.

Further, it is preferable that the delayed tack layer contains an inorganic pigment.

The inorganic pigment contained in the delayed tack layer is preferably colloidal silica.

The mixing ratio of the pigment and the pressure-sensitive adhesive contained in the delayed tack layer is preferably in the range of 20 to 200 solid parts by weight of pigment with respect to 100 parts by weight of solid adhesive.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As the base material according to the present invention, either a transparent material or an opaque material may be adopted. When a transparent sheet of polyethylene terephthalate is used as the substrate, after printing the reverse image of the normal printed image,
By sticking it on an opaque adherend, the printed surface can be protected. When an opaque sheet such as paper is used as the base material, the printed surface can be protected by sticking it on a transparent adherend after printing a normal printed image. Further, in the opaque base material, a constitution in which the other surface not provided with the delayed tack layer is provided with the ink jet recording suitability is also adopted. That is, by printing on both surfaces of the base material and then sticking it to a transparent adherend, the printed surface can be identified from either side of the adherend. Examples of such applications include labels for glass containers.

The constituent components of the ink receiving layer according to the present invention include silica, colloidal silica, surface-treated cationic colloidal silica, alumina sol, cationic aluminum oxide or its hydrate, pseudoboehmite, aluminum silicate, magnesium silicate, Inorganic pigments such as magnesium carbonate can be used.

In addition to the above-mentioned components, the constituent components of the ink receiving layer according to the present invention include commonly used aqueous polymer binders such as polyvinyl alcohol, silyl-modified polyvinyl alcohol, vinyl acetate, oxidized starch, etherified starch, Cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, casein, gelatin, soybean protein, etc .; Maleic anhydride resin, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, etc., conjugated diene copolymer aqueous binder; acrylic acid Acrylic polymer aqueous binder such as ester or methacrylic acid ester polymer or copolymer, acrylic acid and methacrylic acid polymer or copolymer; vinyl polymer aqueous binder such as ethylene vinyl acetate copolymer; or these Aqueous binders of functional polymers modified with functional group-containing monomers such as carboxyl groups of various polymers; Aqueous binders of thermosetting synthetic resin such as melamine resin and urea resin; Polymethylmethacrylate, polyurethane resin, unsaturated polyester Examples thereof include resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, alkyd resins, and other synthetic resin binders, and at least one or more types can be used. Further, a cationic resin may be used together for the purpose of fixing the dye contained in the inkjet ink.

The mixing ratio of the aqueous polymer binder in the ink receiving layer according to the present invention is preferably 5 to 50 parts by weight based on 100 parts by weight of the inorganic pigment. When the mixing ratio is less than this range, the surface of the ink receiving layer is easily cracked,
It is not preferable because the gloss is lowered, the dot reproducibility is deteriorated, and an image with high sharpness cannot be obtained. On the other hand, if it exceeds this range, the ink absorbency is lowered, which is not preferable.

Further, in the present invention, when the ink receiving layer is formed on a transparent substrate, in order to enhance transparency and / or glossiness, an organic system is used instead of the composition of the inorganic pigment-aqueous binder. It is also possible to use a polymer. For example, polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymer, a resin composition mainly composed of polyvinyl alcohol, a copolymer of vinyl alcohol and an olefin, a copolymer of styrene and maleic anhydride,
Cross-linked product of polyethylene oxide and isocyanate,
A mixture of carboxymethyl cellulose and polyethylene oxide, a polymer obtained by grafting methacrylamide on polyvinyl alcohol, an acrylic polymer having a carboxyl group, a polyvinyl acetal polymer,
Examples include crosslinkable acrylic polymers.

In the ink receiving layer according to the present invention, in addition to the above-mentioned components, various kinds of pigments, hardening agents, preservatives, dyes, ultraviolet absorbers, antioxidants, pH adjusters, defoaming agents and the like may be added as required. Additives can be added.

As the solid plasticizer used in the delayed tack layer in the present invention, diphenyl phthalate, dihexyl phthalate, dicyclohexyl phthalate, dihydroabietyl phthalate, dimethyl isophthalate, sucrose benzoate, ethylene glycol dibenzoate, Melting point of tribenzoic acid glyceride, pentabenzotrilitate tetrabenzoate, sucrose octaacetate, tricyclohexyl citrate, etc., catechol dipalmitate, catechol distearate, catechol dibenzoate, stearyl stearate, behenic acid monoglyceride, monoglyceride stearate, etc. Examples include various ester compounds having a temperature of about 40 to 130 ° C., and these are used as an aqueous dispersion after being atomized by a wet or dry pulverization method. Also,
Instead of the above solid plasticizer, liquid plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate and dibutyl maleate can also be used as the solid plasticizer according to the present invention if they are microencapsulated into an apparent solid. Is.

The pressure-sensitive adhesive used in the delayed tack layer in the present invention has a glass transition temperature (Tg) of 20 ° C.
Below, preferably a thermoplastic resin emulsion having a temperature of 0 ° C. or lower is used, and examples thereof include acrylic acid ester copolymer, styrene-acrylic acid ester copolymer, styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, vinyl acetate. -Acrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-acrylic acid ester copolymer, ethylene-acrylic acid copolymer, polybutadiene,
Examples of the resin include polyurethane. These may be used alone or in combination.

Examples of the tackifier used in the delayed tack layer in the present invention include terpene resin, aliphatic petroleum resin, aromatic petroleum resin, coumarone-indene resin, styrene resin, phenol resin and terpene-phenol resin. , Rosin derivatives (rosin, polymerized rosin, hydrogenated rosin and their esters with glycerin, pentaerythritol, etc., resin acid dimers, etc.).

The delayed tack layer according to the present invention comprises:
Further, an inorganic pigment having a good ink absorbability used for the ink receiving layer may be used in combination. As the inorganic pigment, particles having a small particle size, for example, colloidal silica are preferable. When a pigment such as silica having an average particle diameter of the order of 1 μm and a relatively large particle diameter is used, the pigment sticks out from the delayed tack layer, which hinders the adhesiveness during heat activation.

The mixing ratio of the tackifier in the delayed tack layer in the delayed tack type pressure-sensitive adhesive sheet of the present invention is preferably 50 to 250 parts by weight per 100 parts by weight of the solid adhesive. When the mixing ratio is less than this range, the tackiness is extremely poor, and when it exceeds this range, the composition becomes too hard and the tackiness is poor. The mixing ratio of the solid plasticizer is 50 to 50 with respect to 100 parts by weight of the solid adhesive.
A range of 0 parts by weight is preferred. If the mixing ratio is less than this range, blocking is very likely to occur, and if it exceeds this range, the adhesive strength is lowered and choking is likely to occur.

In the present invention, when the delayed tack layer is made to contain a pigment having good ink absorbency, the mixing ratio of the pigment is 2 with respect to 100 parts by weight of the adhesive.
A range of 0 to 200 parts by weight is preferable. Furthermore, 30-
A range of 160 parts by weight is preferred. Furthermore, 40-14
A range of 0 is preferred. If the mixing ratio is less than this range,
Bleeding is likely to occur in an inkjet image, and if it exceeds this range, the adhesive strength is reduced.

The layer structure of the delayed tack type pressure-sensitive adhesive sheet of the present invention may be a laminated layer or a single layer. In the case of stacking, the ink receiving layer and the delayed tack layer are applied in this order on the substrate. In the opposite layer structure, the delayed tack layer does not exist on the surface, so that the tackiness does not appear even when activated. The coating amount of the ink receiving layer varies depending on the type of the substrate and the composition of the coating liquid, but is usually 0.5 to 5 in dry coating amount.
It is applied in the range of 0 g / m ² . The coating amount of delayed tack layer varies depending on the material of the packaging material to be adhesive composition and adhesive, but usually 1 to 30 g / m ² on a dry coating amount, preferably is coated in the range of 5 to 25 g / m ² It In the case of a single layer, the delayed tack layer coating liquid and the ink receiving layer coating liquid are mixed in advance and the dry coating amount is applied in the range of 1 to 50 g / m ² .

The drying temperature after coating is set to 50 ° C. or lower, preferably 40 ° C. or lower. If the drying temperature is higher than that, the delayed tack layer is activated and develops tackiness, which is not preferable.

The delayed tack type pressure-sensitive adhesive sheet of the present invention is activated by being heated for a short time with a heater, a hot air burner, a heat stamp or the like, and exhibits tackiness. The activation time is preferably in the range of 1 to 30 seconds. Activation is carried out at a temperature 5-10 ° C below the melting point of the solid plasticizer.

[0026]

EXAMPLES The present invention will now be described with reference to examples, but the contents of the present invention are not limited to the examples. In addition,
The percentages and parts in the examples refer to solid parts by weight.

Production Example 1 of Ink Receptive Layer Colloidal silica (trade name: Snowtex-20, average particle size of about 0.01 μm) is used as a medium for absorbing ink.
m, manufactured by Nissan Chemical Co., Ltd.) and 10 parts of a water-soluble polymer (trade name: PVA117, manufactured by Kuraray Co., Ltd.) as an adhesive were uniformly mixed to prepare an ink receiving layer coating liquid. An ink jet recording sheet was prepared by applying a coating solution having the above composition to a base paper of LBKP having a basis weight of 85 g / m ^{2 so} that the dry coating amount was 25 g / m ² and drying.

Production Example 2 of Ink Receiving Layer In Production Example 1 of ink receiving layer, silica (trade name: Nipsil E220A, trade name:
An inkjet recording sheet was produced in exactly the same manner except that an average particle diameter of about 1.0 μm, manufactured by Nippon Silica Industry Co., Ltd. was used.

Production Example 3 of Ink Receiving Layer In Production Example 1 of ink receiving layer, about 100 as a substrate
An inkjet recording sheet was produced in exactly the same manner except that a polyethylene terephthalate film having a thickness of μm was used.

Example 1 200 parts of dicyclohexyl phthalate (manufactured by Chukyo Yushi Co., Ltd.) as a solid plasticizer, 150 parts of ethylene / vinyl acetate copolymer (trade name: Sumikaflex-751, manufactured by Sumitomo Chemical Co., Ltd.) as an adhesive, adhesive 100 parts of a rosin-based resin (trade name: SE-E-720, manufactured by Arakawa Chemical Co., Ltd.) as an imparting agent, colloidal silica (trade name: Snowtex-20, average particle size of about 0.01 μm, Nissan as an ink absorbing medium) (Manufactured by Kagaku) was uniformly mixed to prepare a delayed tack layer coating liquid. Bg 85g / m consisting of LBKP
The base paper of No. ² is coated with the above-mentioned coating solution in a dry coating amount of 20 g / m ²
And was dried at 40 ° C. to prepare a delayed tack type pressure-sensitive adhesive sheet having an ink receiving layer.

Example 2 200 parts of dicyclohexyl phthalate (produced by Chukyo Yushi Co., Ltd.) as a solid plasticizer, 150 parts of ethylene / vinyl acetate copolymer (trade name: Sumikaflex-751, manufactured by Sumitomo Chemical Co., Ltd.) as an adhesive, adhesive A delayed tack layer coating liquid was prepared by uniformly mixing 100 parts of a rosin-based resin (trade name: SE-E-720, manufactured by Arakawa Chemical Co., Ltd.) as an imparting agent. On the ink-receiving layer of the ink jet recording sheet shown in Production Example 1 of ink-receiving layer, the coating liquid having the above-mentioned composition was applied at a dry coating amount of 6 g
/ M ² was laminated and coated and dried at 40 ° C. to prepare a delayed tack type pressure-sensitive adhesive sheet having an ink receiving layer.

Example 3 200 parts of dicyclohexyl phthalate (produced by Chukyo Yushi Co., Ltd.) as a solid plasticizer, 150 parts of ethylene / vinyl acetate copolymer (trade name: Sumikaflex-751, manufactured by Sumitomo Chemical Co., Ltd.) as an adhesive, adhesive 100 parts of a rosin-based resin (trade name: SE-E-720, manufactured by Arakawa Chemical Co., Ltd.) as an imparting agent, colloidal silica (trade name: Snowtex-20, average particle size of about 0.01 μm, Nissan as an ink absorbing medium) (Manufactured by Kagaku) was uniformly mixed to prepare a delayed tack layer coating liquid. Ink-Receptor Layer The ink-receptive layer of the ink jet recording sheet shown in Production Example 1 was coated with the coating solution having the above composition so that the dry coating amount was 10 g / m ² , and dried at 40 ° C. A delayed tack type pressure-sensitive adhesive sheet having a receiving layer was produced.

Example 4 Example 3 was repeated except that the ink jet recording sheet shown in Production Example 2 of the ink receiving layer was used in place of the ink jet recording sheet shown in Production Example 1 of the ink receiving layer used in Example 3. A delayed tack type pressure-sensitive adhesive sheet having an ink receiving layer was prepared in the same manner as in.

Example 5 Example 3 was repeated except that the ink jet recording sheet shown in Production Example 3 of ink receiving layer was used in place of the ink jet recording sheet shown in Production example 1 of ink receiving layer used in Example 3. A delayed tack type pressure-sensitive adhesive sheet having an ink receiving layer was prepared in the same manner as in.

Example 6 Instead of 150 parts of colloidal silica which is the medium for absorbing ink used in Example 4, 100 parts of silica (trade name: Nipsil E220A, average particle diameter about 1.0 μm, manufactured by Nippon Silica Industry Co., Ltd.) A delayed tack-type pressure-sensitive adhesive sheet having an ink receiving layer was prepared in the same manner as in Example 4, except that the coating liquid for delayed tack layer was applied.

Example 7 100 parts of silica (trade name: Nipsil E220A, average particle diameter of about 1.0 μm, manufactured by Nippon Silica Industry Co., Ltd.) instead of 150 parts of the colloidal silica which is the medium for absorbing ink used in Example 5 A delayed tack type pressure-sensitive adhesive sheet having an ink receiving layer was prepared in the same manner as in Example 5, except that the coating liquid for delayed tack layer was applied.

Example 8 A delayed tack type pressure-sensitive adhesive sheet having an ink receiving layer was prepared in the same manner as in Example 3 except that the colloidal silica used in Example 3 was changed to 30 parts.

Example 9 A delayed tack type pressure-sensitive adhesive sheet having an ink receiving layer was produced in the same manner as in Example 3 except that the colloidal silica used in Example 3 was changed to 300 parts.

Comparative Example 1 A delayed tack type was carried out in the same manner as in Example 2 except that a base paper of LBKP having a basis weight of 85 g / m ² was used in place of the ink jet recording sheet shown in Production Example 1 of the ink receiving layer. An adhesive sheet was produced.

The delayed tack type pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were heated in an atmosphere of 80 ° C. for 30 seconds to develop their tackiness, and then rapidly adhered to a stainless steel plate to measure a 180 ° peel force. The following criteria were evaluated. A: 800 g / 25 mm or more C: 300 g / 25 mm or more and less than 800 g / 25 mm X ... 300 g / 25 mm or less

The printed surface was evaluated by rubbing the image area with a finger 5 minutes after printing with an ink jet printer (BJC-600J; manufactured by Canon Sales Co., Ltd.) and evaluating the ink absorbency according to the following criteria. ○… Good △… Within practical limits ×… Inferior

[0042]

[Table 1]

In Example 1, the ink receiving layer and the delate tack layer were formed as a single layer. Example 2 has a structure in which an ink receiving layer and a delate tack layer are laminated in this order on a substrate. In any case, it was possible to produce a delayed tack type pressure-sensitive adhesive sheet having both the adhesive strength and the ink absorbability. In Examples 3 to 5, the ink receiving layer and the delayed tack layer were laminated in this order on the substrate, and the delayed tack layer further contained colloidal silica. Examples 3 to 5
In the form (3), the ink absorbency was improved, which was more preferable. In Examples 6 and 7, the ink receiving layer and the delayed tack layer were laminated in this order, and the delayed tack layer contained silica. With this configuration, although the adhesive force was slightly reduced, the ink absorbability was improved. Since the average particle size of silica is 1.0 μm, which is larger than 0.01 μm of colloidal silica, the pigment sticks out from the delayed tack layer, which hinders the adhesion to the adherend during heat activation. Conceivable. In Examples 8 and 9, the ink receiving layer and the delayed tack layer were laminated in this order on the substrate, and the content of colloidal silica in the delayed tack layer was set to 100
The composition is 20 and 200 solid parts by weight with respect to the solid parts by weight, respectively. When the content of colloidal silica is less than the value shown in Example 8, ink bleeding occurs, which is not preferable. Further, when the content of colloidal silica is higher than that in Example 9, the adhesive force when activated is lowered.

Comparative Example 1 has a structure in which only the delayed tack layer is provided on the base material. In this constitution, although the adhesive force at the time of heat activation was sufficient, almost no ink absorption was observed.

[0045]

As is apparent from the examples, the surface of the substrate on which the ink receiving layer is provided has thermotack characteristics so that a delayed tack type pressure-sensitive adhesive sheet which can be printed on the pressure-sensitive adhesive surface can be obtained. became. With respect to the constitution, the object can be achieved even when the ink receiving layer and the delayed tack layer are laminated in this order on the substrate, or when the above components are constituted by a single layer. INDUSTRIAL APPLICABILITY The delayed tack type pressure-sensitive adhesive sheet of the present invention can be used as a label or tape which is required to have durability and water resistance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Takagami 3-4-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Paper Mills, Ltd.

Claims (5)

[Claims] 1. An ink receiving layer is provided on at least one surface of a substrate, and a delayed tack layer comprising a solid plasticizer, a pressure sensitive adhesive and a tackifier is provided on the same surface as the surface having the ink receiving layer. Delayed tack type adhesive sheet characterized by. 2. The delayed tack type pressure-sensitive adhesive sheet according to claim 1, wherein an ink receiving layer and a delayed tack layer are laminated in this order on a substrate. 3. The delayed tack type pressure-sensitive adhesive sheet according to claim 2, wherein the delayed tack layer contains an inorganic pigment. 4. The delayed tack type pressure-sensitive adhesive sheet according to claim 3, wherein the inorganic pigment is colloidal silica. 5. The mixing ratio of the pigment and the pressure-sensitive adhesive contained in the delayed tack layer is in the range of 20 to 200 solid parts by weight of pigment with respect to 100 parts by weight of solid adhesive. Delayed tack type adhesive sheet.