JP3008317B2 - Method for producing glassine release paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing adhesive release paper, and more particularly to a method for producing glassine release paper using a solventless silicone release agent.

[0002]

2. Description of the Related Art Adhesive sheets are used in a wide variety of applications such as commercial, office and home use, and are used for labels, seals, stickers, and the like.
It is used as an emblem and the like. The general configuration of this pressure-sensitive adhesive sheet is such that a pressure-sensitive adhesive layer and a release layer are formed between a surface substrate and a base paper for release paper. An intermediate layer may be provided between the base paper for release paper and the release layer. The release paper is obtained by forming a release layer on a base paper for release paper.

As base paper for release paper, glassine paper, clay-coated paper, super calender paper, polylaminate paper, plastic film, or the like is used, and as a release agent, an emulsion or a solvent type or solventless type silicone compound is used. Many. Paper, film, metal foil, and the like are used as the surface substrate, and the adhesive is a rubber-based, acrylic, vinyl ether-based emulsion-based, solvent-based, or solvent-free adhesive.

[0004] Glassine release paper is effectively used in a printing process and a printer labeling process to perform position detection using a photoelectric tube device by utilizing its transparency. Also, since a relatively thin release paper can be obtained,
By taking advantage of the feature that the area can be increased with respect to the winding diameter and the size of the case, it occupies an important position as an adhesive release paper.

In general, in a method for producing a release paper, a release layer is formed by applying a solvent-type silicone release agent, which is used by diluting a silicone compound with a solvent as a release agent, to a base paper for release paper. The solvent-type silicone release agent can appropriately adjust the quality required for the release agent, for example, the setting of the release force or the fluidity when applying the release agent, and the covering of the base paper surface with the release agent is easy. It has been most often used, taking advantage of the characteristic of a solvent-type release agent that can be made into a solvent.

However, in recent years, there has been a strong demand for consideration of safety and pollution, and it has been strongly desired to stop using a solvent and switch to a solventless silicone release agent, especially from the viewpoint of maintaining the health of workers. .

When a solvent type release agent is coated on a base paper, the amount of the coating liquid can be increased since the release agent is diluted with a solvent. Since no solvent is used when coating on top, the amount of liquid to be coated is small because the solid content of the release agent becomes the coating amount as it is.

Therefore, when a solventless release agent is used, a thinner and uniform release agent film must be formed on the base paper for release paper as compared with the solvent type release agent. As the base paper for the release paper, for example, when using conventional glassine paper, it is difficult to sufficiently cover the surface of the glassine paper with the solventless release agent, and a uniform layer of the release agent film can be formed. Did not.

When an adhesive is coated on the release paper in such a state, a step of forming an adhesive layer on the release agent layer is performed,
A phenomenon is observed in which the pressure-sensitive adhesive enters the pinholes or recesses of the release layer, and after the pressure-sensitive adhesive layer is peeled off from the release paper together with the surface substrate, the pressure-sensitive adhesive remains on the release paper (called adhesive residue).

[0010] This adhesive residue is used to print and die cut (punch) the adhesive product in the form printing and seal printing processes.
When removing the cake, the adhesive adheres to a guide roll or the like that comes into contact with the surface of the release agent layer after the cake removal, causing troubles such as poor paper feeding and printing misalignment, which is a very serious obstacle to workability and quality. Also, in the step of performing printing or labeling with an auto-labeler, a handler labeler, or the like, the problem of adhesive residue on the surface of the release agent layer similarly occurs.

[0011]

The present invention relates to a release paper using a solventless silicone release agent for glassine release paper, and more particularly, to a release agent layer (film) constituting the release paper having pinholes or irregularities. It is an object of the present invention to provide a method for producing glassine release paper, which eliminates the adhesive residue phenomenon without generating the problem and improves the workability in a printing process and a labeling process.

[0012]

According to the present invention, there is provided a method for producing a glassine release paper for adhesion, comprising coating a surface of glassine base paper with a coating liquid containing polyvinyl alcohol as a main component using a blade coater type coating machine. A method for producing a glassine release paper, comprising providing an intermediate layer, and applying a solventless silicone release agent thereon to provide a release layer.

[0013]

The present inventors have studied glassine release paper using a solvent-free silicone release agent, especially for a glassine release paper free of glue residue caused by an adhesive entering pinholes or recesses on a release agent layer. We have been conducting diligent research on development. As a result, using a blade coater type coating machine on the release agent-coated surface of the glassine base paper, a coating liquid containing polyvinyl alcohol as a main component was applied to form an intermediate layer, and a solvent-free silicone release agent was formed thereon. It has been found that by coating the composition, excellent glassine release paper having no adhesive residue phenomenon can be obtained.

[0014] The glassine paper is mainly composed of softwood chemical pulp as a raw material for papermaking, is strongly beaten, is made acidic or neutral, and is finished by super calendering. As the pulp, for example, pulp from high-grade softwood such as spruce and hemlock is optimal. Mix and blend to take advantage of its properties. Further, papermaking raw materials are adjusted and blended with various papermaking chemicals such as sizing agents, paper strength agents, drainage agents, dyes and the like as various additives.
The beating degree of pulp can be improved to oil resistance and transparency by strongly beaten to 250 ml or less with Canadian Standard Freeness. However, problems are likely to occur in papermaking properties and humidity dimensional stability, so that the medium is beaten to a medium degree and the quality characteristics of glassine are assisted by a size press or the like. In the super calendering, for example, pressure, temperature, speed, paper moisture and the like are adjusted.

The method for producing glassine release paper of the present invention is characterized in that an intermediate layer is provided by using a blade coater type coating machine. By this manufacturing method, it becomes possible to apply the solvent-free silicone release agent without pinholes and unevenness. The blade coater method is a method in which a large amount of coating liquid once applied is directly contacted with a blade or rod to scrape off the coating liquid and smooth the measurement.If this method is used to apply an intermediate layer of glassine paper, it will have a pinhole barrier property. Has a significant effect.

When a solventless silicone release agent is applied to glassine paper coated with an intermediate layer using a transfer or printing type coating machine such as a roll size press method or a roll coater method to produce a release paper, for example, Even if the coating amount of the intermediate layer is increased, defects such as pinholes still remain, and the adhesive residue phenomenon cannot be improved unless the coating amount of the release agent layer is increased. Coating of these systems is performed within the range where the tension, Beck smoothness and Gurley high-pressure air permeability of glassine paper can be satisfied by the penetration pattern of the intermediate layer coating liquid into the base paper due to the nip pressure of the roll and the coating pattern at the time of transfer. Even so, the pinhole barrier property is not sufficient.

The intermediate layer coating solution is an aqueous coating solution containing polyvinyl alcohol as a main component. Polyvinyl alcohol is used by appropriately selecting the degree of saponification and the degree of polymerization. For example, various modified polyvinyl alcohols such as carboxy-modified, acetoacetyl-modified, and silicon-modified can also be used effectively.
Further, for example, other adhesives, water-proofing agents, oil-proofing agents, curing agents, clarifying agents, coloring agents, defoaming agents, lubricants, release agents, inorganic organic pigments, and the like are appropriately added as assistants.

In the present invention, an intermediate layer is coated on glassine base paper using a blade coater type coating machine. The coating amount of the intermediate layer is 0.4 to 1.6 g / solid as solid content.
m ² , more preferably 0.5 to 1.0 g / m ² .
When the amount is less than 0.4 g / m ² , the pinhole barrier property is not sufficient, and beating, papermaking conditions, and coating with a release agent are undesirably increased. On the other hand, a large amount of coating exceeding 1.6 g / m ² is not preferable because it burdens the economy and coating suitability of the intermediate layer.

As the coating machine of the blade coater type of the present invention, for example, trailing blades, flooded nip blades, fountain blades, short dwell blades, differential building blades, velvapa blades and the like are used. Dwell blades are preferred. It is also possible to use rods for the blade holders of these coaters. Further, whether the coater is installed on-machine or off-machine is optimally selected depending on the manufacturing process and the type of manufacturing in the factory. In the case of mainly making glassine paper, it is preferable to use an on-machine machine, since the efficiency of the process and the comprehensive control of quality can be achieved. On the other hand, when the intermediate layer is applied after the super calender treatment after being turned off machine, the coating amount can be further reduced, and a soft calender or the like may be provided after the coater is dried.

The glassine paper has a tension of 1.00 to 1.25 g.
/ Cm ³ , more preferably 1.05 to 1.20 g / cm
^{Assume 3} . By the way, if the tension is less than 1.00 g / cm ³ , transparency and sufficient smoothness as glassine paper cannot be obtained. Therefore, when the solvent-free silicone release agent is applied, the covering of the release agent becomes poor, and pinholes and the like are easily generated on the release paper, which is not preferable. It should be noted that this problem can be solved by using a large amount of the release agent, but using a large amount of the release agent is problematic in terms of economy. On the other hand, 1.
If it exceeds 30 g / cm ³ , the voids between the fibers become small, and if placed in a humid atmosphere, moisture is absorbed into the fibers, and the distortion between the fibers due to the expansion of the fibers cannot be absorbed. It is not preferable because the processability and workability during application of an agent, application of an adhesive, printing, use of labeling, etc. are liable to be reduced.

Beck smoothness of glassine paper (JIS-P-
8119) is adjusted to 400 seconds / 10 ml or more, more preferably 500 seconds / 10 ml or more. 400 seconds / 10m
When the value is less than 1, the covering of the release agent is poor because the smoothness is not sufficient, and pinholes and the like occur on the release paper,
Next, after the pressure-sensitive adhesive layer is applied, a glue residue phenomenon occurs to cause a problem.

Gurley high-pressure air permeability of glassine paper (TAPP)
(IT536-om88) is set to 3000 seconds / 100 ml or more, more preferably 5000 seconds / 100 ml or more. If it is less than 3,000 seconds / 10 ml, the coating suitability of the release agent when applying the solvent-free silicone release agent cannot be sufficiently obtained.

The solvent-free silicone release agent used in the present invention includes a thermosetting silicone compound, a UV curing silicone compound, and an EB curing silicone compound. As a method of applying these, a multi-stage roll coater, a gravure coater or the like is used. Coating amount is 0.5 to 1.5 g / m ² approximately in this case, more preferably is appropriately adjusted in the range of about 0.5 to 1.0 g / m ^2.
When the coating amount is less than 0.5 g / m ² , the effect as a release agent layer is inferior. On the other hand, when the coating amount exceeds 1.5 g / m ² , it is not economically practical.

Examples of the pressure-sensitive adhesive include natural rubber, styrene-butadiene copolymer, styrene-isoprene block copolymer, recycled rubber, synthetic rubber and other rubber-based, acrylic and silicone-based adhesives. These pressure-sensitive adhesives are applied in the form of a solvent system, an aqueous emulsion system, a hot melt system, a liquid curing type or the like, for example, by a knife coater, a roll coater, a die coater, a gravure coater, screen printing, or the like. The coating amount in this case is 10% by dry weight.
To 40 g / m ² approximately, it is preferably adjusted in the range of about 15-25 g / m ^2. If the amount is less than 10 g / m ² , the effect of the pressure-sensitive adhesive layer is poor, and if the amount exceeds 40 g / m ² , the effect is saturated, and it is economically undesirable.

As a method for producing a pressure-sensitive adhesive sheet, a transfer method in which a pressure-sensitive adhesive layer is formed on a release paper and then a surface substrate is bonded, or a pressure-sensitive adhesive is directly applied to the surface substrate, and then a release paper is bonded. A direct method can also be used. As the surface substrate, for example, cast coated paper, art paper, coated paper, high quality paper, thermal paper, synthetic paper, vapor-deposited paper, cloth,
Non-woven fabric, metal foil, various polymer films and the like can be used as appropriate.

[0026]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted to such specific Examples. Unless otherwise specified, parts and% in the examples indicate “parts by weight” and “% by weight”, respectively, and the coating amount, the number of parts, the mixing ratio, and the like are all indicated by solid content.

Examples 1 to 3 NBKP 80 parts each having a freeness of 190 ml and LB
Rosin size as a sizing agent in pulp slurry of 20 parts of KP (trade name "Size Pine E", manufactured by Arakawa Chemical Industries)
Was added to the absolutely dry pulp at 0.4%. After adding a sulfuric acid band to the pulp slurry and fixing it, papermaking was carried out with a fourdrinier paper machine, and 2.0 g of an aqueous solution of oxidized starch (trade name "Ace A", manufactured by Oji Cornstarch Co., Ltd.) was solidified on both sides.
/ M ² by size press coating with a two-roll size press to obtain a base paper having a basis weight of 70 g / m ² .

An aqueous solution of polyvinyl alcohol (trade name “PVA117” manufactured by Kuraray Co., Ltd.) was applied to the release paper coating surface of the base paper by an off-machine short dowel coater in an amount of 1.5 g / m ² (Example 1). , 1.0 g / m
² (Example 2), 0.5 g / m ² (Example 3) After coating, the paper moisture was adjusted to 9 to 10%, and the intermediate paper was prepared using a multi-stage super calender comprising a metal roll and an elastic roll. The paper is passed so that the layer surface is entirely in contact with the metal roll and the back surface is in contact with the elastic roll. Tension 1.08 ± 0.02, Beck smoothness 800 ± 200 seconds / 10ml, Gurley high-pressure air permeability 5000 ± 2000 seconds / 100 ml to obtain glassine paper.

Solvent-free silicone release agent (a mixture of 100 parts of KNS-320 and 2 parts of PL-56, manufactured by Shin-Etsu Chemical Co., Ltd.) on the surface of the intermediate layer of the glassine paper. With a gravure coater, each 0.6
5 g / m ² (Example 1), 0.77 g / m ² (Example 2), and 0.82 g / m ² (Example 3) were applied and dried with hot air to obtain glassine release paper.

An emulsion type adhesive (trade name "TS-662", manufactured by Nippon Carbide Co., Ltd.) is applied to each release paper.
Was applied with a reverse roll coater so as to have a weight of 22 g / m ² , dried, and then bonded to a high-quality paper having a basis weight of 64 g / m ² to obtain an adhesive paper, and the adhesive residue was evaluated.

Examples 4 to 6 70 parts of NBKP and LB each having a freeness of 170 ml
Alkyl ketene dimer (trade name "Size Pine K901" manufactured by Arakawa Chemical Industries) is used as a sizing agent in 30 parts of pulp slurry with respect to pulp at 0.13%, cationic polymer, polyamide epichlorohydrin resin (trade name "Kaimen 557H" Dick Hercules) Was added to the pulp at 0.13%, and the paper was made in the same manner as in Examples 1-3.
A size press was performed to obtain a base paper having a basis weight of 87 g / m ² .

An aqueous solution of modified polyvinyl alcohol (trade name “T-350” manufactured by Nippon Synthetic Chemical Co., Ltd.) was applied to the base paper at a coating amount of 1.5 g / m ² (Example 4) and 1.0 g / m ² , respectively.
² (Example 5), 0.5 g / m ² (Example 6) Glassin paper was obtained in the same manner as in Examples 1 to 3, except that coating was performed.

A solvent-free silicone release agent (trade name "BY24-551A" was
Parts, a mixture obtained by adding 30 parts of a product name "BY24-551B", manufactured by Dow Corning Toray Silicone Co., Ltd.) to 0.65 g / m ² (Example 4) and 0.74 g / m ² (Example 5), 0.80 g
/ M ² (Example 6) and UV cured to obtain glassine release paper.

A hot-melt type pressure-sensitive adhesive (trade name “Durotack MQ940K”, manufactured by Kanebo NSC) was applied to this glassine release paper with a die coater to a weight of 25 g / m ² , dried, and then dried to obtain a basis weight of 85 g / m ^2. to obtain a pressure-sensitive paper by bonding a cast coated paper m ^2, it was subjected to adhesive residue evaluation.

Comparative Example 1 A paper was made with a fourdrinier paper machine in the same manner as in Example 1, and an aqueous solution of polyvinyl alcohol (trade name “PVA117”, manufactured by Kuraray Co., Ltd.) became 2.5 g / m ^{2 in} solid content on both sides. And apply it to the intermediate layer using a two-roll size press.

The subsequent intermediate layer was not coated and the paper
A glassine paper was obtained in the same manner as in Example 1 except that the amount was adjusted to 10% and the coating amount of the release agent was 0.86 g / m ^2, and the pressure-sensitive adhesive paper was evaluated.

The release paper and adhesive paper thus obtained were evaluated by the following methods and are shown in Table 1.

[Evaluation of Pinhole Barrier Property] The surface of the release agent of the release paper was uniformly coated with a commercially available oil-based pen, and evaluated by the number of pinholes in 10 cm ² appearing on the back surface. (Evaluation criteria)…: 0 ○: 1 to 10 ×: 10 or more

[Evaluation of Adhesive Remaining Phenomenon] After the surface substrate and the pressure-sensitive adhesive layer were peeled off from the pressure-sensitive adhesive paper, the release agent surface of the release paper and P
The ET film surface was rubbed, the adhesive remaining on the release agent surface was transferred to the PET surface, and the amount of the transferred adhesive was evaluated. (Evaluation criteria)…: Adhesive residue is not so noticeable. Δ: Glue residue is somewhat noticeable. ×: The adhesive residue is conspicuous.

[0040]

[Table 1]

[0041]

As is evident from the results of the examples, both the comparative examples and the comparative examples have the following advantages as glassine paper:
The quality control items of Gurley high-pressure air permeability are all within the preferred range, whereas the comparative examples have problems with pinhole barrier properties and adhesive residue, whereas glassine release paper obtained by the production method of the present invention. Has good release agent covering when coated with solventless silicone release agent on glassine paper, provides a uniform release agent coating, has excellent pinhole barrier properties, and adhesive residue phenomenon that occurs after adhesive application. It was an excellent glassine release paper with no blemishes.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-1043 (JP, A) JP-A-2-191796 (JP, A) JP-A-49-55753 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) D21H 19/00-27/10

Claims (3)

(57) [Claims] In a method for producing an adhesive glassine release paper, an intermediate layer is provided on a surface of glassine base paper by applying a coating liquid containing polyvinyl alcohol as a main component using a blade coater type coating machine. A method for producing glassine release paper, comprising applying a solventless silicone release agent to form a release layer. 2. The method for producing glassine release paper according to claim 1, wherein the coating amount of the intermediate layer is 0.4 to 1.6 g / m ² per one side as a solid content. 3. The coating amount of the solvent-free silicone release agent is 0.
5~1.5g / m ² a glassine release paper manufacturing method according to claim 1, wherein.