JPS62149779A - Peelable self-adhesive - Google Patents

Abstract

PURPOSE:To obtain the titled self-adhesive which causes neither surface contamination nor paper plucking of an adherend, does not leave fine self-adhesive particles thereon, and has excellent adhesiveness and peelability, by sticking a plurality of fine self-adhesive particles to at least one side of a base material through a specified undercoating layer. CONSTITUTION:An undercoating material is obtained by mixing 15-35wt% vinyl chloride-vinyl acetate resin composed of 85-98wt% vinyl chloride having a glass transition temperature of 50 deg.C or higher and a degree of polymerization of 100 or higher, 15-2wt% vinyl acetate and, if necessary, 0-10wt% PVA, with 85-65wt% inorganic pigment such as zinc white, titanium white, clay or calcium carbonate. 90-100wt% (meth)acrylic ester and 10-0wt% vinyl monomer containing reactive functional groups are polymerized to give fine self-adhesive particles having a glass transition temperature of -10 deg.C or lower and a particle diameter of 1-150mu. A solution of the undercoating material in an organic solvent is applied to at least one side of a base material, such as a sheet of paper, a (nonwoven) fabric or a sheet, and is dried to provide a thickness of the undercoating of 0.5mu or more. A dispersion of the fine self-adhesive particles in an organic solvent is then applied on this undercoating layer in an amount sufficient to provide a coating of 0.1-100g/m<2> (dry weight).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an adhesive material with good removability, and more specifically, even when repeatedly pasted and peeled off from an adherend,
The present invention relates to a releasable adhesive material in which no adhesive microparticles remain on the surface of the adherend.

[Prior Art] Removable adhesive tapes or sheets using adhesive fine particles as constituent elements are already known, but in conventional removable adhesive tapes, etc.,
When pasting and peeling are performed, there is a problem in that fine particles, which are adhesive components, remain on the adherend. This problem was noticeable when the adherend was diazocopy paper.

Therefore, in order to solve this problem, in order to fix the microparticles on the base material, the adhesive spherical amount should be reduced to 1/2.
Removable adhesive tapes using a binder of about 115% are known (for example, West German Patent No. 2,41
(See Japanese Utility Model Application No. 7,312, Japanese Utility Model Application Publication No. 54-60661, and Japanese Utility Model Application Publication No. 55-42881).

However, even when such a binder is used, the adhesion of the microparticles is not sufficient, and when rapid peeling is performed, there is still a problem that the microparticles remain on the adherend.

Furthermore, in order to more firmly adhere microparticles to a base material, a method of using an adhesive such as an acrylic emulsion type adhesive as a binder has been considered (see US Pat. No. 3,857,731).

However, even with this method, the adhesion of the microparticles is still insufficient, and a new problem has arisen in that not only the microparticles but also the adhesive used as a binder remains on the adherend.

Furthermore, an invention is also known in which adhesive microparticles having a substantially semispherical shape are adhered onto an undercoat layer formed on a base material without using a binder (see Japanese Utility Model Publication No. 57-57394).

However, in this invention, the adhesive microparticles are limited to a substantially hemispherical shape, and are always fixed to the substrate with the curved surface facing outward, that is, with the contact area between the substrate and the microparticles being larger. It has become necessary to

[Problems to be Solved by the Invention] The present invention solves the above-mentioned problem, that is, when pasting and happing are repeatedly performed on an adherend, sticky microparticles remain on the surface of the adherend. This was done in an attempt to solve the problem.

[Means for Solving the Problems] The present inventors conducted intensive research to solve the above problems, and found that conventionally, removable adhesive bodies using adhesive microparticles do not have the above-mentioned problems. The microparticles are formed by the action of a binder or by a method of increasing the contact area between the undercoat layer and the microparticles (for example, the method described in Utility Model Publication No. 57-5739 mentioned above).
However, by using an undercoat layer that can specifically bond with adhesive microparticles, it is possible to eliminate the need for a binder.
The present inventors have also discovered that even when the contact area is extremely small, it is possible to bond the base material and the adhesive microparticles more firmly, and have completed the present invention.

That is, the removable adhesive body of the present invention has a plurality of adhesives coated on at least one surface of the base material via an undercoat layer consisting of 35 to 15% by weight of a vinyl chloride-vinyl acetate resin and 65 to 85% by weight of an inorganic pigment. It is characterized by the fact that it has small particles attached to it.

The undercoat layer, which is a component of the adhesive body, is composed of an undercoat consisting of a vinyl chloride-vinyl acetate resin and an inorganic pigment.

The vinyl chloride-vinyl acetate resin, which is a component of the undercoat, has a glass transition temperature of usually 50° C. or lower and a degree of polymerization of 100 or higher, preferably 300 or lower. Moreover, this resin consists of 85-98% vinyl chloride and 15-11% vinyl acetate. In addition, 0-10% by weight of borihinyl alcohol can also be contained.

In addition, examples of inorganic pigments include monochrome, titanium white, warping force, calcium carbonate, clay, lead white, and magnesium oxide, which can be used in one weighed amount.

The blending ratio of resin and inorganic pigment in the undercoat is 15
~35% by weight/85-65% by weight, preferably 20-3
0% by weight/80-70% by weight. The amount of resin blended is 1
In the case of 5% by weight non-cat, a part of the pigment does not mix with the resin and there is a pigment-only part, which not only makes it impossible to obtain a uniform system as an undercoat, but also significantly reduces the strength and causes scratches and scratches.
It may peel off when bent. Moreover, if it exceeds 35% by weight, the anchoring properties of the adhesive microparticles will deteriorate and detachment of the microparticles will occur.

Furthermore, if necessary, a water resistance agent, a stabilizer, a barrier property improver, an antiblocking agent, a dye, etc. can be added to the undercoat within a range that does not impair the performance.

The undercoat layer can be formed by adding the undercoat to an organic solvent, kneading and dissolving the mixture, and then applying the mixture to at least one surface of the base material.

Examples of the organic solvent used here include esters such as ethyl acetate and butyl acetate. In addition, these esters include alcohols such as methyl alcohol and butyl alcohol, ketones such as acetone and methyl ethyl ketone, n-hexane, cyclohexane, heptane,
Organic solvents such as mineral spirits, toluene, aliphatic and aromatic hydrocarbons such as xylene, and the like can be used in one weight mixture.

The kneading and dissolution can be carried out using a ball mill, a sand mill, a three-roll mill, or the like after adding the undercoating agent to an organic solvent.

In this case, if a ball mill or sand mill is used, the total solid content in the primer solution is 30% by weight.
In order to improve the kneading effect, it is preferable to adjust the kneading amount to a certain degree, and in the case of three rolls, to make it more than that. Further, the obtained undercoat has a nominal viscosity of 1 to 1ooOcp (2
It is preferable that the temperature is 0° C. and the total solid content concentration is 3Qi%.

The primer solution thus obtained is then applied to at least one surface of the substrate to form a primer layer.

Examples of base materials used here include fibrous base materials such as paper, cloth, and nonwoven fabrics, as well as polyethylene, polypropylene, polyester, polyvinyl chloride, cellulose acetate,
Examples include smooth films and sheets such as polycarbonate, cellophane, polyvinylidene fluoride sheets and films, and composite substrates of these materials.

The undercoat can be applied to the base material using, for example, a gravure coater, a mare coater, a roll coater, an air knife coater, or the like.

In this case, the thickness of the undercoat layer is 0.5 g or more, preferably 1 to 5 g.

After forming the undercoat layer in this way,
Drying is carried out for 20 to 300 seconds at a temperature of 0.degree. C. Next, adhesive microparticles are applied and adhered onto the undercoat layer.

Adhesive microparticles can be prepared, for example, from (meth)acrylic esters or (meth)acrylic esters and vinyl monomers containing reactive functional groups, such as those described in US Pat. No. 3,691,140. It can be produced by a turbidity polymerization method.

(Meth)acrylic acid ester usually has a glass transition temperature of 1.
The temperature is preferably 0°C or lower, preferably 0°C or lower. Such (meth)acrylic esters usually have 2 carbon atoms.
having ~12 linear or branched alkyl groups (
meth)acrylic acid esters, such as butyl (meth)acrylate, isobutyl (meth)acrylate, 5ec
-Butyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, inoctyl (meth)acrylate
Acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, methyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl (
Meth)acrylate, stearyl (meth)acrylate, etc. can be mentioned, and these can be used in one weight amount. In order to increase the cohesive force of the microparticles, in other words, when using the microparticles as an adhesive, it is necessary to prevent the adhesive from remaining on the adherend by causing a stringing phenomenon when peeled from the adherend. In order to achieve
You can add it below.

The reactive functional group-containing vinyl thread polymer to be copolymerized with (meth)acrylic acid ester contains a carboxyl group, hydroxyl group, amino group, glycidyl group, methyl group, formyl group, mercapto group, etc. in one molecule. or acid anhydrides. Examples of such vinyl yarn picks include (meth)acrylic acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, N-methylol (meth)acrylamide, and N-butoxy Examples include methyl (meth)acrylamide, (meth)acrylic acid amide, and maleic anhydride.

Although the shape of the microparticles is not particularly limited, it is preferably spherical because it provides the best removability. Moreover, the average particle system is 1 to 150 pL, preferably 5
~1 ooll is good.

A method for applying such adhesive microparticles onto the undercoat layer is to coat the microparticles with n-hexane, n-hebutane, toluene, xylene, ethyl acetate, butyl acetate,
, 1.1-) After dispersing in an organic solvent such as dichloroethane, the usual coating method using a knife coater, reverse roll coater, gravure coater, or screen printing machine,
Alternatively, a spraying method or the like can be used.

In this case, the amount of coating is calculated as: 1 on dry weight basis
~100g/ln', preferably 1-30g/rr+'
Good.

After applying and adhering the adhesive microparticles in this manner, the adhesive body of the present invention can be obtained by drying at 60 to 120°C for 30 to 300 seconds.

[Effects of the Invention] As explained above, in the removable adhesive body of the present invention, the undercoat layer formed on Omura and the adhesive microparticles are strongly bonded to each other without using a binder. Therefore, it maintains excellent adhesion to the adherend, and at the same time, when pasting and peeling are repeated,
Furthermore, it also has excellent removability in that even if rapid peeling is performed, no sticky microparticles remain on the adherend.

Therefore, there is no surface staining that occurs when the adherend is a transparent material such as plastic, and there is no so-called "paper stain" that occurs when the adherend is paper such as diazocopy paper.

Furthermore, since the adhesive body of the present invention does not use a binder, it is possible to shorten manufacturing time and reduce manufacturing costs.

[Examples of the Invention] Hereinafter, the present invention will be described in detail with reference to Examples, but the scope of the present invention is not particularly limited by the Examples. In the examples, "parts" and "1%" refer to "parts by weight" and "% by weight," respectively.

Example 1 Vinyl chloride-vinyl acetate resin consisting of 91% vinyl chloride, 3% vinyl acetate, and 6% polyvinyl alcohol (trade name Denkavinyl #1000GKT Denki Kagaku Kogyo ■
Next, 24 parts of zinc white was added to the solution and stirred for 10 minutes in a sand mill. This was applied to one side of a sheet of high-quality paper weighing 70 g/rn' using a gravure coater to a coating thickness of 1 tt. Adhesive microparticles (average particle diameter: 508 L) obtained by suspension polymerization were coated onto this by a screen printer at a dry weight of 10 g/g.

The resulting adhesive sheet was cut to a width of 25 mm, and then crimped onto wet diazo copy paper once with a 5 kg roll.
After 1 hour, the copy paper was peeled off in a 180 degree direction at a peeling speed of foCm/min, and no paper stains or adhesive residue was observed on the copy paper. Note that the peel strength at this time was 250 g/25 mm.

Example 2 Vinyl chloride-vinyl acetate resin (Denkarac #21
(manufactured by Denki Kagaku Kogyo ■) 9g toluene, ethyl acetate l:1
Next, 21 g of rutile titanium white dissolved in 70 g of the mixed liquid was added thereto, and the mixture was mixed and ground for 12 hours using a ball mill. This was applied to a 25 μm thick polyester film using a mare bar to give a coating thickness of 1 μm. This was coated with the same adhesive fine particles as in Example 1 using a knife coater so that the drying weight was 8 g/m', thereby obtaining the adhesive body of the present invention.

When an adhesion test similar to that in Example 1 was conducted using this adhesive, there was no diazo copying paper or adhesive residue. At this time, the peel strength was 220 g/25 mm.

Comparative Example 1 Vinyl chloride-vinyl acetate resin (Denkarac #10
A 10% vinegar solution (manufactured by Denki Kagaku Kogyo Co., Ltd.) was applied to a 1.5-thickness coat of high-quality paper with a weight of 70 g/m' using a mare bar. The adhesive fine particles used in Example 1 were applied to this using a screen printer to give a dry weight of 10 g/m' to obtain a sticky body.

When an adhesion test was conducted using this adhesive, there was no paper smearing, but residual adhesive microparticles were observed on the entire surface of the peeled copy paper.

The peel strength in this case was 150 g/25 mm.

Claims (2)

[Claims] (1) A plurality of adhesive microparticles are attached to at least one surface of the base material via an undercoat layer consisting of 35 to 15% by weight of vinyl chloride-vinyl acetate resin and 65 to 85% by weight of inorganic pigment. A removable adhesive body characterized by: (2) The adhesive microparticles are a copolymer consisting of 90 to 100% by weight of ester of acrylic acid or methacrylic acid and 0 to 10% by weight of a vinyl monomer containing a reactive functional group, and the particle size is in the range of 1 to 150μ. The removable adhesive body according to claim 1, which has a glass transition temperature of −10° C. or less.