JP3250340B2 - Glassine paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to glassine paper. More specifically, when used as a release paper for adhesive paper composed of a surface substrate, an adhesive, and release paper, light transmission that has no problem with label position detection by a labeler with a transmission type position detector Further, the present invention relates to a glassine paper having good disintegration properties which can be used as a raw material of recycled paper.

[0002]

2. Description of the Related Art Adhesive paper is generally composed of a surface substrate, an adhesive and a release paper.
Labels, stickers, stickers,
It is used after being processed into the form of patches. The surface base material can be classified into a high-quality paper type, a coated paper type, a cast-coated paper type, and other special types according to its type. As special types, aluminum foil laminated paper, aluminum evaporated paper, resin-impregnated paper, thermal recording paper, etc. are used. Adhesives are often rubber-based or acrylic-based.Among these, acrylics are mainly composed of acrylic acid esters, copolymers of acrylic acid, methacrylic acid, acrylamide, vinyl acetate, styrene, acrylonitrile, etc. There are many things of the system.

[0003] Release papers can be classified into polyethylene laminate type, glassine type, super calendered craft type, clay coat type, aqueous resin coat type, film base type and the like. Among them, polyethylene laminate type and glassine type are often used. In the polyethylene laminate type, high-quality paper, kraft paper, or the like is used as base paper, and polyethylene is laminated to prevent penetration of a release agent such as silicon. As the polyethylene, a high pressure method low density polyethylene is typical.

[0004] When glassine paper is used as the base paper, the release agent may be directly applied because the penetration of the release agent is small. This type is characterized by good light transmission. For example, in a supermarket or the like, a weighing label attached to meat, fresh fish, prepared food, or the like is often used by printing a bar code or the like on an adhesive paper having thermal paper as a surface base material. The adhesive paper after printing and die-cutting is rolled, set on a label printer, and barcodes and prices are printed on each sheet. At this time, the adhesive paper is used to detect the position of the surface substrate. And the light transmittance of the release paper. For this reason, a glassine type having good light transmittance is generally used as a release paper used for such purposes.

[0005] In the labeler, after the adhesive paper is used, the release paper is no longer required and is wound up. Such a release paper has been conventionally treated as industrial waste. However, recently, from the standpoint of environmental protection and forest protection, there is an increasing tendency to collect glassine-type release paper as used paper and reuse it. However, the drawback of these types of release paper is that the pulp fibers are highly beaten and densified, so if they are to be reused as raw materials for recycled paper,
The disintegration in water is poor, and even if a disintegration device such as a pulper is used, the pulp fibers are present in a entangled state, resulting in large flocs during papermaking and defects.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide glassine paper having excellent light transmittance and good disintegration properties which can be used as a raw material for recycled paper.

[0007]

According to the present invention, the Cobb method sizing degree (JIS P81) was measured using a pulp having a freeness of 130 to 240 ml CSF and a contact time of 30 seconds.
40) is 35 to 65 g / m ² . The present inventors have conducted intensive studies to obtain a glassine paper having a disintegration property that can be used as a raw material of recycled paper without impairing the light transmittance, and as a result, the disintegration is closely related to the water absorption of the paper. In connection with this, it has been found that the paper having a higher water absorption has a better disintegration property.

Conventionally, glassine paper has used an internal sizing agent so that a water-based paint can be applied after papermaking, and the Cobb method sizing degree has been set to 30 g / m ² or less. , The Cobb method sizing degree (JIS P8140) measured at a contact time of 30 seconds is from 35 to 6
5 g / m ² . More preferably, 40 to 60 g / m ²
It is. If it is less than 35 g / m ² , water does not sufficiently penetrate into the paper layer during pulverization with a pulper,
The bond between the pulp fibers cannot be loosened, the fibers remain unraveled, and large flocs occur,
It becomes a defect. On the other hand, if it is more than 65 g / m ² , the affinity for water becomes too strong, so that in the state of the adhesive paper, the moisture absorption of the release paper is large, and the curl due to the elongation of the release paper being too large compared to the elongation of the surface substrate. Is worse,
This is a practical problem.

In the papermaking process, the pulp is usually beaten using a beater such as a beater, a jordan, a conical refiner, a single refiner, a double refiner, a deluxe refiner, etc., mainly for the purpose of improving the strength of the paper. Is being done. Freeness is
It is used as a measure of the degree of beating of pulp, and it is known that as the beating progresses, the freeness becomes smaller, and that the paper made from pulp having a smaller freeness becomes more transparent.

In the present invention, the pulp has a freeness of 130 to 240 ml CSF. More preferably, it is 150 to 200 ml CSF. If it is smaller than 130 ml, fibrillation of the pulp fiber proceeds, and the bond between the fibers of the formed paper becomes too strong, so that the disintegration at the time of reuse deteriorates. On the other hand, if it is larger than 240 ml CSF, the transparency will be reduced, and there will be a problem in the position detection by the phototube in the labeler, so that an undesirable result will be given.

In general, for paper stock, chemical pulp such as LKP and NKP, mechanical pulp, deinked waste paper pulp and the like are appropriately used according to the desired paper quality. Internal additives such as a retention improver, a drainage improver, a paper strength enhancer, and a dye are added as necessary, and mixed and prepared by various preparation devices. Then, it is guided to a wire part through a selective process such as a screen, and is finished as a paper through a dewatering process and a drying process.

In the present invention, these known techniques can be used without departing from the scope of the present invention. Various pulps can be used as the pulp used in the present invention. Examples of suitable pulp include chemical pulp obtained by digesting lignocellulosic materials derived from softwood and hardwood with an alkaline cooking chemical. it can. As chemical pulp, Kraft pulp (pulping liquor, NaOH + Na ₂ S), polysulfide pulp (pulping liquor, NaOH + Na ₂ S _X ), soda pulp (pulping liquor, NaOH), sulfite pulp (pulping liquor,
Na ₂ SO ₃ ), sodium carbonate pulp (digestion liquor, Na ₂ C
O ₃ ) and oxygen soda pulp (pulping liquor, O ₂ + NaO
H).

In producing the pulp, a cyclic keto compound (for example, anthraquinone, 1,4-dihydro-9,10-diketoanthracene) is added to the cooking liquor as a cooking aid and cooked. Is also good. Further, as the above-mentioned cooking pulp, a kraft pulp that is more suitable for the purpose of the present invention is a so-called modified alkaline pulp, which comprises divided addition of a cooking liquor, co-current cooking and counter-current cooking inside a digester. Cooking method (M
Pulp obtained by the CC method). These chemical pulp, unbleached pulp, in the state of bleached pulp, are used alone or mixed as appropriate, bleached pulp,
It is more suitable for this purpose. Waste ink pulp (DIP)
Of course, it does not matter if it is used in combination with the like.

As fillers for internal addition, talc, kaolin,
Clay, calcined kaolin, calcium carbonate, aluminum hydroxide, polystyrene resin fine particles and the like can be mentioned, but in this paper, it is better to avoid using a large amount of filler or to keep it to a very small amount from the viewpoint of transparency.

Examples of the internal sizing agent include alkyl ketene dimer sizing agent, alkenyl succinic anhydride sizing agent, stearic anhydride sizing agent, petroleum resin sizing agent, rosin sizing agent, and wax sizing agent. I can give it. In the present invention, selection of these sizing agents and adjustment of the addition amount are important for obtaining a target Cobb method sizing degree.

A retention improver and a drainage improver may be selected and used as needed. For example, Al, Fe, Sn, Zn
And polyvalent metal compounds (sulfuric acid band, aluminum chloride, etc.). Examples of the paper strength enhancer include various raw starches, various processed starches, various polyacrylamides, and polyvinyl alcohol. Examples of the wet paper strength enhancer include melamine-formaldehyde resin, urea-formaldehyde resin, epoxidized polyamide polyamine resin, polyethyleneimine and the like. Since these paper strength enhancers and wet paper strength enhancers may cause the disintegration to deteriorate, it is desirable to keep them to the minimum necessary. However, there are some which give good results in terms of transparency.

Other internal additives include dyes, optical brighteners, pH adjusters, defoamers, pitch control agents, slime control agents and the like. The surface size can be adjusted mainly for the purpose of improving the surface strength. Examples of the surface sizing agent include various starches, various polyacrylamides, various polyvinyl alcohols, carboxymethyl cellulose, acrylates, α-olefin maleic anhydride copolymers, styrene acrylic copolymers, and latex.

When the surface sizing agent is applied, the method and the like are not particularly limited. For example, a two-roll or metaling blade type size press, a gate roll, a bill blade, a short dwell coater, a roll coater Various methods such as an air knife coater and a blade coater can be appropriately used. From the aspect of disintegration, a two-roll or metalling blade type size press gives better results.

The papermaking method is not particularly limited. For example, an acidic papermaking method in which the papermaking pH is around 4.5, a neutral papermaking in which the pH during papermaking is from about 6 slightly acidic to about 9 slightly alkaline. Method or the like can be used. As the paper machine, a fourdrinier paper machine, a twin-wire paper machine, a circular net paper machine, a Yankee paper machine, or the like can be appropriately used. It is extremely effective for this purpose to increase the degree of transparency by providing a degree press and a machine calendar to increase the degree of tension. Applying a pressure finish using an on or off super calender, soft calender, or the like is also extremely effective. In this case, the higher the paper moisture, the better the transparency and the better the transparency. The paper moisture is desirably 6% or more and 10% or less.

The glassine paper produced in this way has excellent light transmittance and good disintegration that can be used as a raw material for recycled paper. Its use is most suitable for paper used as release paper in labelers and the like having a transmission type position detector, but other than that, for example, food packaging, pharmaceutical packaging, cakes, chocolate cups, transparent envelopes It can be used in many fields, such as windows.

When the glassine paper of the present invention is used as a release paper, in order to efficiently prevent the release agent such as silicon from penetrating into the base paper, a known polyethylene or the like may be laminated, or polyvinyl alcohol, casein may be used. It can also be efficiently prevented by providing an undercoat layer mainly composed of, for example. It may be applied directly on glassine paper. The processing into the adhesive paper may be performed by any known method.

[0022]

The present invention will be described below with reference to Examples 1 to 9 and Comparative Examples 1 to 8.
However, the scope of the present invention is not limited thereto. % Indicates% by weight. Unbleached pulp is produced by a Kraft cooking method using a conifer consisting of domestic hardwood, 15% Douglas fir, 10% hemlock, and 75% domestic pine in a Kamiya continuous digester, followed by oxygen bleaching and CEH. -D bleached hardwood bleached pulp (hereinafter referred to as LB) having a whiteness of 85
KP) and softwood bleached pulp (hereinafter referred to as NBKP). These pulp are LBKP: NBKP
= 50: 50 and freeness is 10
A double disc refiner (DDR) and a deluxe refiner were combined and beaten to obtain 0, 130, 180, 240, and 270 ml CSF. Further, a rosin-based sizing agent (SPE, manufactured by Arakawa Chemical Co., Ltd.) and a sulfuric acid band were added so that the ratio of the absolutely dried pulp was 100%, and the ratio was as shown in Table 1.

This stock was converted to a rice net by 64 g / m by a fourdrinier paper machine.
Paper ^{2 was formed} , and after pressing with tension, PVA was applied by a ^two- roll size press such that the coating amount was 0.5 g / m ^2.
(Nippon Synthetic Chemical Co., GH-20, saponification degree: 88) was applied and dried to reduce the water content to 7.0%. Each of the papers thus obtained was super-calendered. Further, a release agent silicone SRX-211 (manufactured by Toray Silicone Co., Ltd.) was applied to a Meyer bar at 1.0 g / m ² (in terms of solid content).
It was applied, dried and cured to produce a release paper.

An acrylic emulsion pressure-sensitive adhesive (Sibinol AT-560, manufactured by Seiden Chemical Co., Ltd.) was applied to the release-coated surface of these release papers with a Mayer bar so that the dry weight was 25 g / m ² . Subsequently, a rice tsubo 7 having a protective layer provided on the heat-sensitive recording layer as a surface base material on the pressure-sensitive adhesive layer was used.
A 2 g / m ² leuco dye-based thermosensitive recording paper was overlaid and bonded with a press roll.

The thus obtained 17 kinds of adhesive papers were subjected to label punching to prepare a label for thermal recording, and a label printer DP-2600IV manufactured by Teraoka Seiko was used.
The suitability for detecting the position of the surface paper when issuing labels was examined. In Table 1, ○ indicates that the position could be detected without any problem, and X indicates that there was a problem with the position detection by the phototube and label flow occurred.

Curling characteristics under high humidity are as follows: 30 ° C., 85%
The sample cut to A4 size under the RH environment was placed on a horizontal table, and the heights of the four corners from the horizontal table were examined and averaged. Table 1
The symbol ○ in the figure indicates that the level is 15 mm or less, which is no problem, and the symbol X, which is larger than 15 mm, is a level that is problematic in practical use. Furthermore, the disintegration properties of each release paper were tested in order to determine whether or not it could be used as recycled paper. The disintegration was performed by cutting 40 g of release paper into 1.5 cm × 1.5 cm, adding 2 liters of hot water (60 ° C.), and disintegrating (disintegrator).
After disintegration for a certain period of time (10 minutes), 71 g of these
The paper was dried with a paper machine and dried, and the presence or absence of floc was visually evaluated. In Table 1, ○ indicates that the material has been sufficiently disintegrated and is at a level that can be used practically as a recycled material, and X indicates that the material has poor disintegration and cannot be used as a recycled material.

[0027]

[Table 1]

[0028]

According to the present invention, it is possible to produce a light-transmitting release paper having no problem in the positioning of the surface substrate by the photoelectric tube, and to provide a glassine paper excellent as a recycled material.

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

Claims (1)

(57) [Claims] 1. Freeness is 130 to 240 ml CS
Using the pulp of F, the Cobb method size (JIS P8140) measured at a contact time of 30 seconds was from 35 to 65 g / m ^2.
Glassine paper characterized by the following.