JPH02294378A - Adhesive of pressure-activating type and adhesive sheet - Google Patents

Abstract

PURPOSE:To obtain the subject adhesive having excellent safety in handling and sufficient adhesive force without adhering in normal condition and adhering under pressure by dispersing microcapsule containing plasticizer in vinyl chloride-based resin, etc. CONSTITUTION:Microcapsule containing plasticizer (preferably phthalic acid derivative, maleic acid derivative or fumaric acid derivative) is dispersed in vinyl chloride-based resin or cellulosic resin (e.g. nitrocellulose, acetylcellulose or cellulose acetate butyrate) to afford the aimed adhesive.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a pressure-activated adhesive used for labels, stickers, tapes, etc., which normally adhere by applying pressure instead of adhesion, and The present invention relates to pressure-activated adhesive sheets such as labels, stickers, tapes, etc., in which an activated adhesive is coated on a support.

(Prior Art) Conventionally, adhesives, rewetting adhesives, and the like have been used to adhere labels, stickers, and tape necks.

However, when an adhesive is used, it is necessary to protect the adhesive layer with a release paper except when adhering.

The release paper is not required after adhesion, and the product cost increases accordingly. Also, when adhering, it is easy to bond because it adheres just by coming into contact with the adherend, but on the other hand, the adhesive may stick to areas other than the adherend, such as hands or the neck of the garment, and it may be difficult to decide the adhesion position. It has the disadvantage that it is very troublesome. Furthermore, when the adhesive is large, wrinkles and misalignment are particularly likely to occur, and in such cases it is difficult to reattach. Remoistening adhesive is used as a method that does not use release paper, but it is difficult to control the moisture content during adhesion and tends to cause wrinkles and dimensional changes after adhesion. or,
As with the case of using adhesive, it is very troublesome to determine the adhesion position.

Various adhesives using microcapsules are known to solve these problems.

For example, an adhesive tape that contains an adhesive in microcapsules and coats the surface of the support wear (Japanese Patent Publication No. 35-9039)
There is a method of microcapsulating an adhesive or a pressure-sensitive adhesive, as shown in FIG. However, many of these adhesive components have high viscosity, and during the microcapsule process, the adhesive may adhere to the microcapsule manufacturing equipment, making it impossible to continue manufacturing, or making it difficult to uniformly reduce the microcapsule particle size. Therefore, the microcapsules are non-uniform and have a large particle size. When an adhesive containing such non-uniform, large-sized microcapsules is applied to an adhesive surface, the coated surface becomes rough and the appearance is damaged, and the non-uniform particle size causes microcapsules to resist pressure. Disadvantages include nonuniform destructibility, and excess adhesion or uneven adhesion during adhesion during processing processes other than the adhesive application process, or during storage after adhesive application and before adhesion. There is. Furthermore, adhesives often contain organic solvents, and the odor of the solvent is a problem, and there are strict restrictions on the usage environment.

Another example that can be used in this field is a method in which an organic solvent is micro-encapsulated and the micro-capsule is destroyed to activate a pre-prepared polymer resin layer (Japanese Patent Laid-Open No. 58-103571, Showa 58-1 36670,
JP-A-59-129281, JP-A-60-60 1 7
3rd prize). However, in these examples, since the organic solvent is microencapsulated, the solvent is released during bonding and not only produces a bad odor, but also has an adverse effect on the human body, and if used in large quantities, there is a risk of fire or explosion. However, there was a problem in that the usage environment was extremely restricted. It is conceivable to use microcapsules of substances that do not have the drawbacks of the above organic solvents, such as oils and odorless plasticizers with low volatility.In fact, the only known substances are plasticizers and aromatic A combination of microencapsulated oil and acrylic resin is known. However, what is proposed here is a combination of plasticizer-containing microcapsules and acrylic resin, and there are only a limited number of acrylic resin components that can provide room-temperature pressure adhesion, so it is necessary to use a flexible acrylic resin in advance. Large amounts of plasticizer may be required to provide adhesive properties.

(Problems to be solved by the present invention) However, when Dairyu's plasticizer is used, the pressure applied during bonding causes the plasticizer to penetrate into the adherend, causing adhesion inhibition or supporting the adhesive. When applied to the body and used as an adhesive sheet, if stored in sheets stacked together, the sheets will adhere to each other before use due to the influence of this resin film due to long-term storage, load during storage, and environmental changes. (called blocking) becomes unusable.

It is possible to reduce the amount of plasticizer by using acrylic resin, which forms a flexible resin film with pressure-adhesive properties, but as in the case above, storing them in sheet form can cause blockage. .

To solve this blocking problem, it is necessary to add a mold release agent or the like, which not only increases costs but also makes it difficult to select a mold release agent, and incorrect addition can cause adhesion inhibition.

The purpose of the present invention is to (l) bond by simply applying pressure; (2)
It does not adhere under any conditions other than the pressure conditions required for adhesion, (3) it is easy to handle during adhesion and does not cause unpleasant smells such as solvent odor, and (4) it can be manufactured at low cost. The object of the present invention is to provide a satisfactory pressure-activated adhesive or an adhesive sheet coated with this adhesive.

(Means and effects for solving the problems) The present invention is the result of intensive studies to solve the above-mentioned drawbacks of conventional adhesives.The present invention is based on the results of intensive studies to solve the above-mentioned drawbacks of conventional adhesives. It has been found that all of the above drawbacks can be overcome by using vinyl chloride resin or cellulose resin as the polymeric resin component activated by the released plasticizer. That is, the present invention provides a pressure-activated adhesive characterized in that microcapsules containing a plasticizer are dispersed in a vinyl chloride resin or cellulose resin film. Furthermore, the present invention provides a pressure-activated adhesive sheet in which the pressure-activated adhesive is coated on a support.

The present invention will be explained in more detail below.

The plasticizer used in the present invention contained in the microcapsules is
Examples include phthalic acid derivatives, maleic acid derivatives, fumaric acid derivatives, phosphoric acid derivatives, adivic acid derivatives, ricinoleic acid derivatives, eboxy derivatives, etc., and they are not limited to single use, but can be used in combination of two or more types as necessary. I can do it.

These plasticizers are appropriately selected depending on the type of vinyl chloride resin or cellulose resin, but for vinyl chloride resin, phthalic acid derivatives, maleic acid derivatives, and fumaric acid derivatives are preferable, and for cellulose resin, preferably phthalic acid derivatives, maleic acid derivatives, and fumaric acid derivatives is preferably a phthalic acid derivative. More preferably, dibutyl phthalate is used as a plasticizer for both the vinyl chloride resin and the cellulose resin to improve adhesiveness after plasticization, hinyl chloride resin,
It is most effective in terms of diffusion into cellulose resin and plasticization efficiency.

Here, the vinyl chloride resin refers to polyvinyl chloride and copolymers whose main components are vinyl chloride monomers, such as vinyl chloride-vinyl acetate copolymers, vinyl chloride-acrylic acid ester copolymers, vinyl chloride-methacrylate copolymers, etc. Examples of cellulose resins include acid copolymers, vinyl chloride-maleic acid copolymers, vinyl chloride-vinylidene chloride copolymers, vinyl chloride-acrylonitrile copolymers, vinyl chloride-vinyl acetate-maleic acid copolymers, etc. Nitrocellulose, acetylcellulose, cellulose acetate butyrate, cellulose brobionate, ethylcellulose, etc. can be used, and can be selected from the above polymer resins depending on the purpose of use and the type of plasticizer.

For example, if a sheet coated with this adhesive is manufactured in roll form, and the support surface facing the coated surface is uneven and easy to adhere to, such as ordinary paper, when the roll is stored, Adhesion between the adhesive layer and the support surface may occur before use due to environmental changes (particularly at high temperatures), storage days, winding pressure, etc. In order to avoid this, a polymer resin component that forms a hard film with good heat resistance is used.

Furthermore, depending on the hardness of the resin used, it is possible to add a polymer plasticizer or the general plasticizer described above to the polymer resin in advance to increase the initial adhesive strength. As the polymer plasticizer, nitrile synthetic rubber, acrylic ester with a low degree of polymerization, etc. are used. The amount of these non-microencapsulated plasticizers added is 30 parts by weight or less, and if it is more than that, it causes excessive adhesion (blocking phenomenon) during storage and before use.

It has also surprisingly been found that by adding a so-called tackifier to the polymer resin, the adhesive force can be significantly increased with a small amount of plasticizer. In other words, we have found that the synergistic effect of the combination of the polymeric resin component, the plasticizer, and the tackifier significantly increases the adhesion strength.As the tackifier, for example, rosin resin , natural resins such as terpene resins, modified rosins such as ester rosin, glycerin ester rosin, pentaerythritol ester rosin, derivatives of rosin and modified rosin, terbenphenol, polymers of α and β pinene. Polyterbene resins such as polyterbenes or their modified products; aliphatic hydrocarbon resins such as olefin and diolefin polymers; phenolic resins such as phenol resins, alkylphenols and modified phenols; xylene resins such as xylene-formaldehyde resins; Coal-based resins such as coumaron indene resins, cyclopentadiene resins, aromatic petroleum resins, alkylphenol-acetylene resins, styrene resins, etc. are used.The softening point of this tackifier is 50- The temperature is preferably 150°C, and if it is lower than that, the anti-blocking property during storage of the vinyl chloride resin or cellulose resin to which a tackifier is added may deteriorate, or the cohesive force may decrease during adhesion. .

Further, if the temperature is 150°C or higher, the effect on the initial adhesive force is halved. The amount of these tackifiers added depends on their softening point, the type of polymer resin used, the type of tackifier,
Although it depends on the combination of types of plasticizers and the usage ratio of plasticizer-containing microcapsules to the polymer resin, it is preferable to add 10 to 100 parts by weight to the polymer resin component from the viewpoint of adhesiveness and cost.

The above plasticizer can be easily microencapsulated by a conventionally known method. For example, a typical microencapsulation method is the interfacial polymerization method (Japanese Patent Publication No. 38-195
74, Japanese Patent Publication No. 42-446, etc.), In Situ Polymerization Method (Japanese Patent Publication No. 37-14327, Special Publication No. 37-1 238)
0, etc.), phase separation method from aqueous solution system (Japanese Patent Publication No. 37-772
4, Special Publication No. 37-3878, etc.), submerged drying method (Special Publication No. 3, No. 3
9-28744, etc.). The essential conditions for this microcapsule are that it is not permeable to plasticizers and that no q-agent is released due to pressure, etc. during the microcapsule manufacturing process, the main adhesive coating process, and processing processes other than bonding. However, it is also possible to adjust the microcapsule rupture property by changing the particle size, film thickness, and film strength depending on the intended use.

In addition, in this adhesive sheet, if the microcapsules satisfy the above-mentioned essential conditions, in addition to the microcapsule breakability, the distribution state of the microcapsules in the adhesive containing the above-mentioned polymeric resin as a main component will also break the microcapsules. It is possible to adjust the gender.

For example, it can be adjusted by adjusting the adhesive coating strength, the ratio of microcapsules to polymer resin, the microcapsule particle size and adhesive layer thickness, the microcapsule coating method, etc. Therefore, when strong pressure is applied during sheet processing, storage, etc., the particle size of the microcapsules must be reduced to prevent excessive adhesion at times other than adhesion. Preferably, microcapsules with a particle size of 5 μm or less are used, and in that case, the amount of the microcapsulated plasticizer added is 10 to 200 parts by weight per 100 parts by weight of the polymer resin. Preservability can be satisfied. In addition, when high adhesive strength is required, if the amount of microcapsules (that is, the amount of plasticizer) is large, the plasticizer will penetrate into the adherend when the microcapsules break, causing adhesion inhibition and at the same time reducing the cohesive force of the adhesive layer. On the other hand, if the amount of plasticizer is small, the adhesive layer will not be sufficiently plasticized and high pressure will be required for bonding. Therefore, if you want to obtain high adhesive strength, preferably add 20 parts of microcapsules to 100 parts by weight of polymer resin.
It is preferable to add up to 150 parts by weight.

The pressure-activated adhesive of the present invention can be applied to labels, stickers, tapes, etc. by coating the above-mentioned adhesive on a suitable support such as paper, plastic film, aluminum foil, aluminum vapor-deposited paper, aluminum laminated paper, etc. It also includes a mold adhesive sheet.

The pressure-activated adhesive of the present invention is particularly useful when used as an adhesive sheet as described above, and furthermore, when the adhesive sheet is to be bonded in large quantities in a short period of time, the adhesive sheet is passed through a pressure roll. It is particularly useful for adhesives that are used alone.

Seals coated with this adhesive do not require the conventional release paper, making it possible to produce inexpensive stickers. Furthermore, since it will not adhere at all under pressure lower than the pressure required for adhesion, when determining the adhesion position, it can be placed freely at the adhesion point, and it will adhere if pressure is applied as it is, making positioning very easy and accurate. . In addition, it is easy to print on the surface of the support other than the adhesive surface, and there is no need to worry about problems such as the release paper and adhesive layer shifting due to the printing pressure during printing, the adhesive sticking to the printing machine, and printing being interrupted. Not at all.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, parts indicate parts by weight.

Microcapsule manufacturing method 1> 60 parts of plasticizer is emulsified in an aqueous solution of 1 part of polyvinyl alcohol, 3.5 parts of styrene-maleic anhydride, and 65.5 parts of water, and while stirring is continued, emulsion is added to 1 mole of melamine. After adding 3.5 moles of formalin and 30 parts of melamine-formalin Hatsutomo condensate into the emulsion, the pH was adjusted to 5.
A conventionally known method in which a melamine-formalin resin microcapsule film containing a plasticizer is produced by lowering the temperature to 60 to 60 °C and raising the temperature of the system to 60 to 80 °C.

Microcapsule manufacturing method 2> Emulsify 15 parts of plasticizer in an aqueous solution of 0.5 parts of gelatin, 0.5 parts of carboxymethylcellulose, and 19 parts of water at 40°C, and add 20 parts of dilution water while continuing to stir. After adding, the pH is adjusted to 3.5 to 4.5 to cause phase separation of seratin and carboxyl methyl cellulose, and each time the temperature of the system is lowered to 10 ° C. or less, the phase separated gelatin and carboxyl methyl cellulose are gelled.
Next, after adding 3 parts of a 37% by weight formaldehyde aqueous solution, a NaOH aqueous solution was added until the pH of the system was 9.0-10.
Conventionally known methods of curing them with each addition until 0.

<Example 1> Dibutyl phthalate-containing microcapsules obtained in Production Method 1 ( A pressure-activated adhesive of the present invention was obtained in which 120 parts (particle size: 44 μm or less) were uniformly dispersed.

This adhesive was coated onto coated paper having a weight of about 84 g/rn2 after drying to form a pressure adhesive sheet.

<Example 2> Vinyl chloride-vinyl acetate copolymer 100 parts (manufactured by Denki Kagaku Kogyo ■; Denka Vinyl 1000) phenolic resin
60 copies (Arakawa Chemical eu!; Tamanol,
Dibutyl phthalate-containing microcapsules (particle size: 44μ
A pressure-activated adhesive of the present invention was obtained in which 85 parts (below) were uniformly dispersed.

This adhesive was coated onto coated paper having a weight of about 84 g/rn2 after drying to give a weight of about 21 g/m2 to form a pressure adhesive sheet.

Example 3 Dibutyl phthalate-containing microcapsules (particle size 28μ or less) obtained by manufacturing method 1 were added to a solution in which 100 parts of nitrocellulose (manufactured by Daicel Chemical) and 15 parts of dibutyl phthalate were dissolved in 560 parts of ethyl acetate.
130 parts were uniformly dispersed to obtain a pressure-activated adhesive of the present invention.

After drying this adhesive on coated paper with a weight of about 76 g/m2,
It was coated to a weight of 3 g/m2 to form a pressure-adhesive sheet.

Example 4 A solution prepared by dissolving 100 parts of nitrocellulose (manufactured by Daicel Chemical Co., Ltd.), 15 parts of dibutyl phthalate, and 50 parts of special-purpose gin ester (manufactured by Arakawa Chemical ■; super ester, softening point 120-130°C) in 560 parts of ethyl acetate. Then, dibutyl phthalate-containing microcapsules (particle size 2
8μ or less) was uniformly dispersed to obtain a pressure-activated adhesive of the present invention.

After drying this adhesive on coated paper with a weight of about 76 g/m2,
It was coated to give a weight of 0 g/m'' to form a pressure-adhesive sheet.

<Example 5> Vinyl chloride latex solid content 47% 213 parts (manufactured by Nippon Zeon ■; Geon Latex) special mouth gin ester solid content 55% 109 parts (manufactured by Arakawa Chemical ■; super ester, softening point 120-130°C) NBR The pressure-activated adhesive of the present invention was prepared by uniformly dispersing 75 parts of dibutyl phthalate-containing microcapsules (particle size of 44 μm or less) obtained in Production Method 1 in 58 parts (manufactured by Nippon Zeon ■; Nipol) with a solid content of 41.5%. I got it.

After drying this adhesive on a high-quality paper of approximately 76 g/m", approximately 18 g/m"
g/m": Coated in a continuous manner to form a pressure-adhesive sheet.

Example 6 A pressure-activated adhesive of the present invention was obtained in the same manner as in Example 5, except that 40 parts of dibutyl phthalate-containing microcapsules (particle size 63 to 125 μ) obtained by microcapsule production method I were uniformly dispersed. Ta.

After drying this adhesive on high-quality paper of about 76g/rn2,
It was coated at a weight of 5 g/rn2 to form a pressure adhesive sheet.

Example 7 A pressure-activated adhesive of the present invention was obtained in the same manner as in Example 5, except that 90 parts of dibutyl malate-containing microcapsules (particle size of 44 μm or less) obtained by Microcapsule Production Method 2 were uniformly dispersed. Ta.

After drying this adhesive on high-quality paper of about 76 g/m2,
．． It was coated to give a pressure adhesive sheet of g/m2.

<Comparative Example 1> 130 parts of dibutyl phthalate-containing microcapsules (particle size 44 μm or less) obtained by microcapsule manufacturing method 1 were added to 340 parts of acrylic resin with a solid content of 29.5% (manufactured by Mitsubishi Rayon ■; Dianal LR-269). A pressure-activated adhesive with uniformly dispersed particles was obtained.

This adhesive was coated on coated paper with a weight of about 76 g/rn2 to a weight of about 30 g/m2 after drying to form a pressure adhesive sheet.

<Comparative Example 2> Acrylic resin solid content 29.5% 340 parts (manufactured by Mitsubishi Rayon ■: Dianal LR-269) dibutyl phthalate 100 parts and microcapsules obtained by microcapsule manufacturing method 1 (particle size 44μ or less)
A pressure-activated adhesive was obtained in which 130 parts of the adhesive was uniformly dispersed.

After drying this adhesive on coated paper of about 76 g/m2, about 1
It was coated to give a weight of 8 g/m2 to form a pressure adhesive sheet.

Comparative Example 3> Vinyl acetate emulsion solid content 50% 200 parts (Showa Kobunshi Kyoku Co., Ltd.; Vorisol S-50) Water
A pressure-activated adhesive was obtained by uniformly dispersing 130 parts of dibutyl phthalate-containing microcapsules (particle size of 44 μm or less) obtained by microcapsule manufacturing method 1 in 100 parts.

After drying this adhesive on high-quality paper of about 76 g/m2,
g/m2 coating to make a pressure adhesive sheet.

<Comparative Example 4> Hinyl acetate emulsion solid content 50% 200 parts (manufactured by Showa Kobunshi Koji; Vorisol S-5) water
A pressure-activated adhesive was obtained by uniformly dispersing 30 parts of dibutyl phthalate-containing microcapsules (particle size of 44 μm or less) obtained by Microcapsule Production Method 1 into 100 parts.

After drying this adhesive on high-quality paper of about 76 g/m2,
g/m" to make a pressure adhesive sheet.

Adhesive properties after stacking the above pressure adhesive sheets and 86 g/m2 foam paper and passing them through a pressure roll with a linear pressure of 30.9 kg/c1I1, and the adhesive properties of these adhesive sheets in roll form.
Blocking resistance (storage stability) after storage at 0℃ for 1 week
is as shown in the table below. ○ indicates almost no blocking, and × indicates blocking and unusable.

When using the adhesive of the present invention, the adhesive of the present invention can be easily bonded by applying pressure without causing excessive adhesion, is safe to handle, has sufficient adhesive strength, and has great industrial utility value. It increases the

Claims (1)

[Scope of Claims] 1) In a pressure-activated adhesive that normally does not adhere but adheres upon application of pressure, microcapsules containing a plasticizer are dispersed in a vinyl chloride resin or a cellulose resin. A pressure-activated adhesive characterized by: 2) The pressure-activated adhesive according to claim 1, characterized in that a tackifier is added to the vinyl chloride resin or the cellulose resin. 3) A pressure-activated adhesive sheet characterized in that at least one side thereof is coated with a pressure-activated adhesive in which microcapsules containing a plasticizer are dispersed in a vinyl chloride resin or a cellulose resin. 4) The pressure-activated adhesive sheet according to claim 3, characterized in that a tackifier is added to the vinyl chloride resin or the cellulose resin.