JP3250638B2 - Release paper base 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 base paper for release paper having excellent dimensional stability and curling resistance.

[0002]

2. Description of the Related Art Release paper base paper is used for the purpose of applying a release agent such as silicone to the surface thereof and using it as a base paper for adhesive paper. A release agent such as silicone is dissolved in an organic solvent and applied to base paper. At that time, in order to facilitate the separation from the adhesive paper, it is necessary to keep the applied release agent on the paper surface without penetrating into the paper layer. For this reason, the base paper used is polyethylene laminated paper, glassine paper or semi-glassine paper, which has a low penetration of organic solvents.

[0003] Polyethylene laminated paper does not penetrate the release agent dissolved in the organic solvent, and the release can be easily controlled. However, because a polyethylene film is used,
There are problems such as large shrinkage due to heat, inability to recover, and high production cost.

On the other hand, glassine paper or semi-glassine paper is sufficiently beaten to minimize the penetration of a release agent, or as described in JP-A-4-327300, a barrier is provided by PVA smear. I have. In other words, semi-glassine release paper base paper forms a water-soluble polymer layer with high barrier properties, suppresses the penetration of the release agent into the paper layer, does not hinder the cure of silicone, and is economically saponified. Polyvinyl alcohol having a degree of 95% or more, oxidized starch, CMC, MC, alginic acid and the like are used.

Incidentally, a polyurea polyamide resin, a melamine resin, glyoxal, etc. are used in combination to prevent blocking of the release paper base paper. The release paper base paper thus produced has a release property close to that of polyethylene laminated paper, and has a better release property than glassine paper.

However, the dimensional stability is not sufficient only by using the above water-soluble polymer. In a general production process of an adhesive paper, a release agent is smeared and dried on a base paper for a release paper, and then an adhesive is smeared and dried on the surface coated with the release agent and bonded to a surface substrate. Therefore, the base paper of the release paper is dried and shrunk twice in the step of smearing the release agent and the adhesive, and the reactivity to moisture is extremely high. Therefore, curling occurs immediately when moisture absorption or the like occurs due to a change in the external environment. Especially when using high-beaten, high-density paper such as glassine paper as the base paper, it shrinks more than ordinary paper when drying,
There are very few voids that can absorb the expansion of the fiber caused by moisture absorption and the like, and curling is remarkable.

[0007] The curl thus generated is punched out,
At the time of processing such as printing and sheet cutting, troubles such as poor paper feed, paper misalignment, and printing misregistration are caused, resulting in serious obstacles in work and quality. Also, the releasability from adhesive paper is inferior to polyethylene laminated paper.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a base paper for release paper having excellent dimensional stability, which is a problem of conventional glassine paper / semi-glassine paper, and having a releasability from adhesive paper comparable to that of polyethylene laminated paper. To provide.

[0009]

SUMMARY OF THE INVENTION The present invention is a base paper for release paper in which a support made of wood fiber having a pulp freeness of 150 to 250 ml CSF is impregnated with a styrene-butadiene latex having a glass transition point of 2 to 40 ° C. That is, the present invention
A support made of wood fiber having a pulp freeness of 150 to 250 ml CSF is impregnated with a styrene-butadiene-based latex having a glass transition point of 2 to 40 ° C., and is calendered to obtain a release paper having excellent release properties and dimensional stability. Base paper can be obtained. The pulp freeness used in the present invention is 1
Below 50 ml CSF, the dimensional stability deteriorates and
If it exceeds mlCSF, the release agent penetrates into the paper layer, and there is a problem in controlling the release strength. That is, in order to prevent the release agent from penetrating into the paper layer and improve the dimensional stability, it is necessary to use one having a beating degree in this range.

As a method for forming a water-soluble polymer layer having a high barrier property, a styrene-butadiene-based latex having excellent mechanical stability, other chemical stability and storage stability is impregnated, and a roll temperature of 70 ° C. or higher. The film is formed by calendering to prevent the release agent from penetrating into the paper layer. The dimensional stability is further improved by impregnating with a styrene-butadiene-based latex.

[0011] Regarding the latex used here, when the glass transition point is 2 ° C or lower, blocking of the base paper occurs, and when the glass transition point is 40 ° C or higher, the film at the time of calendering is used. Is not sufficiently formed, and the release agent penetrates, and there is a problem in controlling the peel strength. That is, the styrene-butadiene-based latex used here must have a glass transition point of 2 to 40 ° C.

As described above, a release paper base paper having excellent dimensional stability, which is a problem of conventional glassine and semi-glassine papers, and having a releasability from an adhesive comparable to that of a polyethylene laminate could be produced.

[0013]

The present invention will be described in more detail with reference to examples.
The air permeability, water immersion elongation, blocking evaluation, mechanical stability, and heat resistance in the examples were evaluated according to the following contents.

Air permeability (denisometer air permeability) According to JIS P-8117, a paper area of 645 mm ^{2 is applied} to air 10
The time for 0 ml to pass is determined.

The dimension in the width direction of the water immersion elongation is measured, and the measured value is defined as A. Next, water temperature 20 ℃
In water for 10 minutes and measure the dimensions at the same location. The water immersion elongation is calculated according to the following equation. Water immersion elongation (%) = (BA) / A × 100

Evaluation of Blocking During the calendering process, the degree of the presence or absence of deposits on the roll was evaluated as follows. ○ No deposits △ Some level but no problem × Deposits

Mechanical stability The impregnating solution or the smear was applied to a Marron tester at a pressure of 20 kg.
Judgment was made based on the presence or absence of a residue after standing for 3 hours at a temperature of 50 ° C. ○ No residue × No residue

Heat-resistant release paper base paper was heated to 200 ° C. to determine whether there was any abnormality. ○ No abnormality × Swelling or peeling occurred between the support base paper and the resin.

Example 1 A pulp raw material composed of 10% NBKP and 90% LBKP was beaten to a freeness of 200 ml CSF, and after adding 0.5% of a wet strength agent (epichlorohydrin resin) to the pulp slurry, the length was increased. Paper having a basis weight of 64 g / m ^{2 was} produced using a mesh paper machine. At this time, a styrene-butadiene-based latex (P-2185 manufactured by Sumitomo Dow) having a glass transition point of 40 ° C. was impregnated at a concentration of 30% by a size press in a process in a paper machine. Thereafter, calendering was performed. Condition is 11Nip
In pressure 60 Kg / cm ² roll temperature was 75 ° C..

Example 2 In the same production method as in Example 1, only the freeness of the pulp raw material was 1
It was beaten to make 50 ml CSF and made into a paper.

Example 3 The same manufacturing method as in Example 1 was applied to only the freeness of the pulp raw material.
It was beaten to make 50 ml CSF and made into a paper.

Example 4 A styrene-butadiene latex having a glass transition point of 2 ° C. (JSR0614 manufactured by Nippon Synthetic Rubber Co., Ltd.) by the same production method as in Example 1.
Was impregnated at a concentration of 30% to produce a paper.

Comparative Example 1 A styrene-butadiene-based latex having a glass transition point of -10 ° C. (JSR0696 made by Nippon Synthetic Rubber) was impregnated at a concentration of 30% by the same production method as in Example 1 to form a paper.

Comparative Example 2 A styrene-butadiene-based latex having a glass transition point of 50 ° C. (Nipoi2507 manufactured by Zeon Corporation) was impregnated at a concentration of 30% in the same production method as in Example 1 to form a paper.

Comparative Example 3 In the same production method as in Example 1, only the freeness of the pulp raw material was 3
It was beaten to make 00 ml CSF and made into a paper.

Comparative Example 4 A pulp raw material having a freeness of 1 was obtained in the same manner as in Example 1.
It was beaten to make 00 ml CSF and made into a paper.

Comparative Example 5 A pulp raw material comprising 10% NBKP and 90% LBKP was beaten to a freeness of 200 ml CSF, and a 0.5% wet strength agent (epichlorohydrin resin) was added to the pulp slurry. With a Fourdrinier paper machine, basis weight 64 g / m ²
Paper was made. Thereafter, the surface was smeared with PVA at a concentration of 30%, and then calendered.

Comparative Example 6 The same manufacturing method as in Comparative Example 5 was carried out except that the surface was changed to a glass transition point of 1 ° C.
Acrylic ester copolymer aqueous dispersion (Furamal B
15 Nippon Acrylic).

Comparative Example 7 Laminated paper in which a paper was used as a base material and a polyethylene film was laminated on one side.

Table 1 shows the measurement results for the examples and comparative examples. In the embodiment, the air permeability of the denisometer is 20,000.
Seconds or more, water immersion elongation is 2% or less, and there is no problem such as blocking. Therefore, a base paper for release paper having excellent release properties and dimensional stability could be obtained.

[0031]

[Table 1]

[0032]

EFFECT OF THE INVENTION Pulp freeness is 150 to 250 ml CS
Glass transition point of 2 to 40 ° C on a support made of wood fiber of F
The styrene-butadiene-based latex was impregnated and calendered to obtain a release paper base paper excellent in releasability, dimensional stability and curling resistance.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) D21H 11/00-27/42

Claims (2)

(57) [Claims] 1. A pulp freeness of 150 to 250 ml CS
Glass transition point 2-4 on base paper made of wood fiber F
Release paper base paper containing styrene butadiene latex at 0 ° C. 2. An air permeability obtained by calendering under a condition where the roll surface temperature is set to 70 ° C. or higher and steam is passed through the inside of the roll is 20,000 seconds or more, and the water immersion elongation is 2% or less. The release paper base paper according to claim 1, wherein