JP7395941B2 - Glass interleaving paper, laminates and packaging - Google Patents

Description

The present invention relates to a glass interleaving paper, a laminate, and a package.

On the surface of glass plates used in flat panel displays such as plasma displays and liquid crystal displays, elements and structures such as minute electrodes and partition walls are formed, so the surface is prone to minute defects such as scratches and foreign objects. is required to be small. Therefore, in order to prevent the glass plates from coming into contact with each other and being damaged, when the glass plates are transported, interleaving paper is usually inserted between the glass plates and the glass plates are packaged.

However, in the method of interposing glass interleaving paper between glass plates, particles in the glass interleaving paper (fibers, paper particles, organic and inorganic foreign substances in the paper, etc.) are transferred to the glass plate, and the device on the glass plate is transferred to the glass plate. The problem was that defects caused by the foreign matter occurred during formation. Therefore, various glass interleaving papers have been developed to suppress particles (for example, Patent Documents 1 to 3).

Japanese Patent Application Publication No. 2016-34843 Japanese Patent Application Publication No. 2005-248409 Patent No. 5137063

However, in recent years, devices formed in the shape of a glass plate have become smaller as displays have become more precise, and there has been an even greater demand for suppressing particle adhesion to the glass plate. Therefore, there is a demand for glass interleaving paper that can further suppress the generation of particles.

The present invention has been made in view of the above, and an object of the present invention is to provide a glass interleaving paper that generates particularly few particles. Another object of the present invention is to provide a laminate in which the glass interleaving paper is interposed between a plurality of glass plates, and a package in which the laminate is housed in a packaging container.

A first aspect of the glass interleaving paper of the present invention that solves the above problems is a glass interleaving paper interposed between glass plates, which has an area within 10 μm from the surface in the thickness direction on at least one surface of the glass interleaving paper. The length-weighted average fiber length of the disintegrated pulp obtained by disintegrating the near-surface region is 0.5 to 3.5 mm, and the fibrillation rate is 0.1 to 4%.
A second aspect of the glass interleaving paper of the present invention that solves the above problems is a glass interleaving paper that is interposed between glass plates, and the length-weighted average fiber length of the disintegrated pulp obtained by disintegrating the glass interleaving paper. is 0.7 to 2.5 mm, and the fibrillation rate is 0.3 to 3%.
In one embodiment of the glass interleaving paper of the present invention, the virgin pulp ratio may be 80% or more.
In one embodiment of the glass interleaving paper of the present invention, the basis weight is 20 to 100 g/m ² , the thickness is 30 to 150 μm, the ash content is 0.5% by mass or less, and the resin content is 0.5% by mass or less. Good too.
In one embodiment of the glass interleaving paper of the present invention, the content of fibers having a fiber length of more than 1.2 mm and 3.2 mm or less in the disintegrated pulp may be 40% by mass or more.
In one embodiment of the glass interleaving paper of the present invention, the content of fibers having a fiber length of 0.2 mm or more and 1.2 mm or less in the disintegrated pulp may be 40% by mass or more.
In one aspect of the glass interleaving paper of the present invention, after the glass interleaving paper is brought into contact with the glass substrate, the contact angle of water on the surface of the glass substrate may be 30° or less.
In one embodiment of the glass interleaving paper of the present invention, the R index may be 0.4 or less.
In one embodiment of the glass interleaving paper of the present invention, the glass interleaving paper may have a rectangular shape, and the length of at least one side may be 500 mm or more.
Moreover, the laminate of the present invention is a laminate in which the glass interleaving paper of the present invention is interposed between a plurality of glass plates.
In one embodiment of the laminate of the present invention, the glass plate may have a thickness of 0.1 to 1.5 mm.
Moreover, the package of the present invention is a package that includes a packaging container and the laminate of the present invention accommodated in the packaging container.

The glass interleaving paper of the present invention generates particularly few particles. Furthermore, in the laminate and package of the present invention, adhesion of particles to the glass plate is suppressed.

FIG. 1 is a sectional view showing a schematic configuration of an example of a laminate using glass interleaving paper according to an embodiment of the present invention. FIG. 2 is a side view showing a schematic configuration of an example of a package according to an embodiment of the present invention. FIG. 3 is a side view showing a schematic configuration of another example of the package according to the embodiment of the present invention.

Hereinafter, embodiments of the glass interleaving paper, laminate, and package of the present invention will be described. Note that the present invention is not limited to the embodiments described below. Furthermore, in the following drawings, members and portions that have the same function may be described with the same reference numerals, and overlapping descriptions may be omitted or simplified. Further, the embodiments illustrated in the drawings are schematically illustrated to clearly explain the present invention, and do not necessarily accurately represent the actual size or scale.

[Glass interleaving paper]
FIG. 1 shows a schematic diagram of a laminate 10 in which a glass interleaving paper 1 of this embodiment is interposed between a plurality of glass plates 2. The glass interleaving paper 1 of this embodiment is a glass interleaving paper interposed between glass plates, and the generation of particles is suppressed, and there are few particles attached to the glass plates that come into contact with it. Below, the glass interleaving paper 1 of this embodiment will be explained in detail.

The present inventors have discovered that the fibrillation rate of the pulp constituting the glass interleaving paper has a correlation with the amount of particles generated. Fibrillation refers to the fact that fibers that have undergone a treatment such as beating swell, partially tear, and become branched. The fibrillation rate is a value representing the degree of fibrillation, and is the ratio of the projection area of small fibers to the projection area of the entire fiber, measured using a fiber image analysis device. A more detailed measurement method will be explained in the Examples section. The higher the fibrillation rate, the more advanced the fibrillation is.
The present inventors have discovered that the higher the fibrillation rate, the more likely fine fibers are to be exfoliated and particles to be generated. That is, the inventors have found that the fibrillation rate has a correlation with the ease with which particles are generated, and that by lowering the fibrillation rate, the generation of particles can be suppressed. From the viewpoint of suppressing the generation of particles, the lower the fibrillation rate, the more preferable.
On the other hand, if the fibrillation rate is too small, the bonds between fibers in the glass interleaving paper will become weak, resulting in a decrease in paper strength, making the paper more likely to tear during operation or use. In addition, it retains less water and dries easily, making it more likely to be charged with static electricity, which may cause a peeling electrification phenomenon when it is peeled off from the glass plate, making it difficult to peel it off properly.
From the above viewpoint, in this embodiment, the range that the fibrillation rate of the dissociated pulp should satisfy is defined. In this embodiment, the following first or second condition for the fibrillation rate is satisfied.

First, the first condition for the fibrillation rate will be explained.
The amount of particles generated largely depends on the state of the fibers in the region within 10 μm in the thickness direction from the surface of the glass interleaving paper (hereinafter also referred to as "near-surface region"), which is near the part that contacts the glass substrate during use. . From this, the first condition for the fibrillation rate defines the fibrillation rate of the disintegrated pulp in this region.
The first condition for the fibrillation rate is to set the fibrillation rate of the disintegrated pulp obtained by disintegrating the area near the surface of the glass interleaving paper to 0.1% or more, preferably 0.2% or more, and more preferably 0.3%. % or more, and 4% or less, preferably 3% or less, more preferably 2% or less, still more preferably 1.5% or less, particularly preferably 1% or less.
Here, in the glass substrate, suppression of contamination is particularly required, that is, suppression of particle adhesion is required on the surface on which electronic circuits are formed. Therefore, the effects of the present invention can be achieved as long as the fiber state of the surface of the glass interleaving paper that touches the electronic circuit forming surface is controlled. Therefore, in the first condition, it is sufficient that the fibrillation rate of the disintegrated pulp obtained by disintegrating the area near the surface of at least one surface of the glass interleaving paper satisfies the above condition. In addition, in order to further suppress contamination of the glass, it is preferable that the fiber state on both sides of the glass interleaving paper is controlled, and therefore it is more preferable that the first condition is satisfied on both surfaces of the glass interleaving paper. . This is because if the surface of the glass substrate opposite to the electronic circuit forming surface is heavily contaminated, the electronic circuit forming line may be contaminated and the contamination of the line may be transferred to the electronic circuit forming surface. The same applies to the average fiber length described below.

Disaggregated pulp in the region near the surface can be obtained by dividing glass interleaving paper in the thickness direction using an appropriate method to separate only the region near the surface, and then disintegrating it.
When dividing the glass interleaving paper in the thickness direction, it is preferable to use a method that does not involve cutting fibers. For example, a method using a sheet splitter (manufactured by Kumagai Riki) that freezes both sides of wet paper and splits it internally, or a method that separates it with adhesive tape and splits it in the thickness direction can be used.

Next, the second condition for the fibrillation rate will be explained.
The second condition defines the fibrillation rate of the disintegrated pulp obtained by disintegrating the entire glass interleaving paper.
Here, since the entire glass interleaving paper contains various fibers, the fibrillation rate of the dissociated pulp obtained by disintegrating the entire glass interleaving paper is the fibrillation rate of the dissociated pulp obtained by disintegrating the area near the surface. It may be slightly different. Therefore, in this embodiment, in order to achieve the above-mentioned effects (suppression of particle generation and suppression of exfoliation charging phenomenon), the fibrillation rate of the disintegrated pulp obtained by disintegrating the entire glass interleaving paper should satisfy the range. The range to be satisfied by the fibrillation rate of the disintegrated pulp obtained by disintegrating the region near the surface of glass interleaving paper is different. More specifically, the range that the fibrillation rate of the disaggregated pulp obtained by disintegrating the entire glass interleaving paper should satisfy is narrower than the range that the fibrillation rate of the disaggregated pulp obtained by disintegrating the area near the surface should satisfy. Become. Note that the same applies to the average fiber length described below.

In the second condition of the fibrillation rate, the fibrillation rate of the disintegrated pulp obtained by disintegrating the glass interleaving paper is 0.3% or more, preferably 0.4% or more, more preferably 0.5% or more, Further, the content is 3% or less, preferably 2% or less, more preferably 1.5% or less, even more preferably 1% or less, particularly preferably 0.7% or less.

Furthermore, if the length-weighted average fiber length of the disintegrated pulp obtained by disintegrating glass interleaving paper (hereinafter simply referred to as "average fiber length of disintegrated pulp") is too short, the fibers may fall off and adhere to the glass substrate. There is. Compared to particles generated due to the fibrillation rate, fallen fibers have weak adhesion to the glass substrate and are easily removed by cleaning, so they have little negative impact on the quality (cleanliness) of the glass substrate, but they have a high level of cleanliness. In order to achieve this, it is necessary to suppress this as well. On the other hand, if the average fiber length of the disintegrated pulp is too long, the formation of the glass interleaving paper may deteriorate and the uniformity of the thickness may decrease.

From the above, in this embodiment, the following first or second condition of average fiber length is satisfied.

In the first condition of the average fiber length, the average fiber length of the disintegrated pulp obtained by disintegrating the area near the surface of the glass interleaving paper is 0.5 mm or more, preferably 0.9 mm or more, and more preferably 1.1 mm or more. , and is also 3.5 mm or less, preferably 3.0 mm or less, more preferably 2.5 mm or less, and even more preferably 2.1 mm or less.

In the second condition of the average fiber length, the average fiber length of the disintegrated pulp obtained by disintegrating the glass interleaving paper is 0.7 mm or more, preferably 0.9 mm or more, more preferably 1.1 mm or more, and 2 .5 mm or less, preferably 2.3 mm or less, more preferably 2.1 mm or less, still more preferably 1.9 mm or less.

In addition, in order to further suppress the falling of fibers, the content of fibers with a fiber length of more than 1.2 mm and 3.2 mm or less in the disintegrated pulp of the entire glass interleaving paper or the disintegrated pulp of the area near the surface should be set to 40 mm. The content is preferably at least 60% by mass, more preferably at least 60% by mass, even more preferably at least 80% by mass.
In addition, in order to improve the formation of the glass interleaving paper and improve the uniformity of its thickness and surface flatness, the fiber length of the disintegrated pulp of the entire glass interleaving paper or the disintegrated pulp of the area near the surface should be 0.2 mm or more. The content of fibers having a diameter of 1.2 mm or less (hereinafter also referred to as "short fibers") is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more.
The content of fibers with a fiber length of more than 1.2 mm and 3.2 mm or less and fibers with a fiber length of 0.2 mm or more and 1.2 mm or less can be measured by the method described in the Examples section.

The freeness of the disintegrated pulp is Canadian Standard Freeness (hereinafter referred to as CSF), preferably 200 ml or more, more preferably 300 ml or more, even more preferably 350 ml or more, and preferably 650 ml or less, more preferably 550 ml or less, and 500 ml or less. More preferred.
The freeness of the disintegrated pulp has a correlation with the amount of beating during production of glass interleaving paper, and as the amount of beating increases, the freeness tends to decrease. It is preferable to beat the disaggregated pulp so that the CSF thereof is 200 to 650 ml because the average fiber length and fibrillation rate of the disaggregated pulp tend to be within the preferable range.
The freeness of disintegrated pulp can be measured in accordance with JIS P 8121-2:2012. The detailed measurement method will be explained in the Examples section.

The average fiber length, fiber length distribution, fibrillation rate, and CSF of defibrated pulp depend on the type of raw material, beating conditions (type of beater, structure, blade material, shape (blade width, groove width, blade length, It can be controlled by appropriately adjusting the groove depth, blade angle), rotation speed, refining strength, fiber slurry concentration, temperature, pH, flow rate, pressure, etc.).

Ash content is an indicator of the amount of metal foreign matter contained in glass interleaving paper. The ash content of the glass interleaving paper of this embodiment is preferably 0.5% or less, more preferably 0.3% or less, even more preferably 0.1% or less, and particularly preferably 0.05% or less. Since the content of metal components in the glass interleaving paper is suppressed by suppressing the ash content, it is possible to suppress the glass interleaving paper from causing minute scratches on the glass plate.
Ash content can be measured in accordance with JIS P 8251:2003. The detailed measurement method will be explained in the Examples section.

The resin content is an index representing the amount of organic matter other than cellulose derived from lignin and the like contained in glass interleaving paper. The resin content of the glass interleaving paper of this embodiment is preferably 0.5% or less, more preferably 0.3% or less, even more preferably 0.1% or less, and particularly preferably 0.05% or less. By suppressing the resin content, it is possible to suppress the organic matter (resin component) in the glass interleaving paper from adhering to the glass plate and causing contamination of the glass.
The resin content can be measured in accordance with JIS P 8224:2002. The detailed measurement method will be explained in the Examples section.

If the surface flatness of the glass interleaving paper of this embodiment is low (degree of unevenness on the order of several to tens of mm), the stacking height when laminating the glass interleaving paper and the glass plate to form a laminate becomes large. Therefore, the number of sheets that can be stored in a container of a predetermined height decreases.
As an index of the surface flatness of glass interleaving paper, the R index measured by the method described in the Examples section can be mentioned. The R index of the glass interleaving paper of this embodiment is preferably 0.4 or less, more preferably 0.3 or less, and even more preferably 0.2 or less.
Since surface flatness changes depending on multiple factors, there are multiple methods for improving surface flatness.
For example, when the proportion of short fibers in the raw material pulp fibers is increased, the texture of the glass interleaving paper is improved and the surface flatness is improved. In order to increase the short fiber ratio of raw material pulp fibers, for example, LBKP with a high short fiber ratio may be used as the raw material pulp. Further, when NBKP is used as the raw material pulp, the short fiber ratio may be increased by beating treatment with stronger cutting.
Further, when the uniformity of the moisture profile in the paper width direction during paper making is improved, changes in surface flatness after drying and moisture absorption are suppressed, and thus surface flatness is improved. In order to improve the uniformity of the moisture profile in the paper width direction during paper making, for example, a steam profiler can be used to control the amount of steam jetted in the width direction, or an infrared heater divided in the width direction can be used to control the amount of heating. All you have to do is
Furthermore, the surface flatness can also be improved by subjecting the glass interleaving paper to a calender treatment.

If the basis weight of the glass interleaving paper of this embodiment is small, there is a possibility that the strength will decrease and it will be easily torn. Therefore, the basis weight of the glass interleaving paper of this embodiment is preferably 20 g/m ² or more, more preferably 30 g/m ² or more, even more preferably 40 g/m ² or more, and particularly preferably 45 g/m ² or more.
On the other hand, if the basis weight is large, the weight will increase, and the stacked height will also increase when glass interleaving paper and glass plates are stacked to form a laminate, so it can be stored in a container of a specified height. The number of sheets will decrease. Therefore, the basis weight of the glass interleaving paper of this embodiment is preferably 100 g/m ² or less, more preferably 90 g/m ² or less, even more preferably 80 g/m ² or less, and particularly preferably 70 g/m ² or less.
The basis weight can be measured in accordance with JIS P 8124:2011. The detailed measurement method will be explained in the Examples section.
Further, from the same viewpoint as above, the thickness of the glass interleaving paper of this embodiment is preferably 30 to 150 μm.

Since the glass plate laminated together with the glass interleaving paper of this embodiment is usually rectangular, it is preferable that the glass interleaving paper of this embodiment also has a rectangular shape. Furthermore, so that it can be used for laminating large glass plates, the glass interleaving paper of this embodiment preferably has a length of at least one rectangular side of 500 mm or more, more preferably 1000 mm or more, It is more preferably 1500 mm or more, and particularly preferably 2200 mm or more. The lower limit is not particularly limited, but is, for example, 4000 mm or less.
For example, if the glass plate is rectangular and measures 2200 mm x 2500 mm, the glass interleaving paper preferably has a rectangular shape of about 2280 mm x 2580 mm. When the glass plate is rectangular, the length of each side of the glass interleaving paper is preferably about 1.02 to 1.05 times the length of the corresponding side of the glass plate.

Moreover, it is preferable that the glass interleaving paper of this embodiment not only suppresses adhesion of particles to the glass plate, but also suppresses contamination of the glass plate (for example, contamination due to resin contained in the glass interleaving paper). An example of an index for evaluating the degree of contamination on a glass plate is the contact angle of water on the surface of the glass substrate after the glass interleaving paper is brought into contact with the glass substrate, which is measured by the method described in the Examples section. It will be done. The contact angle of the glass interleaving paper of this embodiment is preferably 30° or less, more preferably 25° or less, and even more preferably 20° or less.

Various chemicals may be added internally or externally (coated, impregnated, etc.) to the glass interleaving paper of this embodiment as long as the effects of the present invention are achieved. Examples of chemicals added internally or externally to glass interleaving paper include aluminum sulfate, antifoaming agents, fixing agents, paper strength enhancers, retention aids, coagulants, surfactants, sizing agents, antistatic agents, Examples include slime control agents, dryer stripping agents, polyvinyl alcohol, polycrylamide, starch, cellulose derivatives such as CMC, and fillers (talc, clay, titanium dioxide, calcium carbonate, etc.).

Below, as an example of the method for manufacturing glass interleaving paper of the present embodiment, a preparation step of preparing pulp as a raw material, a preparation step of manufacturing pulp slurry from pulp, a paper making step of making glass interleaving paper from pulp slurry, and the like will be described. A manufacturing method having the following will be described. Note that the method for manufacturing glass interleaving paper of this embodiment is not limited to the example described below.

The preparation process is a process of preparing raw material pulp for glass interleaving paper.
The type of raw material pulp is not particularly limited, but one having characteristics required for glass interleaving paper is used. For example, chemical pulps such as kraft pulp (KP), sulfite pulp (SP), and soda pulp (AP); mechanical pulps such as ground wood pulp (GP), thermomechanical pulp (TMP), and chemi-thermomechanical pulp (CTMP); Semi-chemical pulps such as chemical ground pulp (CGP) and semi-chemical pulp (SCP) as mechanical and chemical pulps; non-wood fiber pulps made from kenaf, mulberry, mulberry, hemp, etc.; synthetic pulps , synthetic fibers, waste paper pulp (DIP), and the like. The pulp may be bleached or unbleached; for example, among KPs, hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), softwood unbleached kraft pulp (NUKP) is available. It may also contain carbon nanofibers (CNF).
Since glass interleaving paper requires high cleanliness, the raw material pulp is bleached kraft pulp, which is bleached to reduce the amount of resin and other components derived from lignin. (LBKP and NBKP) are particularly preferred.
These raw material pulps may be waste paper pulp, virgin pulp, or a mixture of waste paper pulp and virgin pulp. Here, virgin pulp is pulp that is not made from waste paper pulp, but is made from paper that has never been used for wood, non-wood, or glass loading purposes. In order to particularly suppress contamination of the glass plate by particles and resin components, it is preferable that the weight ratio of virgin pulp to the total amount of raw material pulp (virgin pulp ratio) is high, and the ratio is preferably 80% or more, and 90% or more. Preferably, 100% is most preferred. Glass interleaving paper with a virgin pulp ratio of 80% or more is generally recognized as high-grade glass interleaving paper, and is sometimes used for packaging glass substrates (high-grade substrates) that require particularly high cleanliness. many. On the other hand, glass interleaving paper with a virgin pulp ratio of less than 80% is generally recognized as low-grade glass interleaving paper, and packaging for glass substrates (low-grade substrates) that do not require the same level of cleanliness as high-grade substrates. It is often used for

In the preparation step, the raw material is diluted with water or the like, and is appropriately beaten using a conical refiner, double disc refiner, etc. to obtain a raw material liquid (pulp slurry).
At this time, the various drugs mentioned above may be added internally. During beating, the beating conditions are changed depending on the type of pulp used and the intended glass interleaving paper, in other words, the characteristics of the disintegrated pulp. Viscosity beating, etc., with the main effect of fibrillation, etc. may be performed as appropriate.

In the papermaking process, the obtained pulp slurry is made into paper using, for example, a Fourdrinier paper machine, a cylinder paper machine, an inclined wire paper machine, or a twin wire paper machine. After passing through the wet end, the wet paper is dehydrated and dried using a multi-barrel dryer, Yankee dryer, etc. If necessary, the above-mentioned chemicals may be applied or impregnated using a roll coater or a blade coater. Further, various types of calendars such as soft calendars and super calendars may be used online or offline.

In particular, methods for producing glass interleaving paper with controlled fiber length distribution and fibrillation rate near the surface layer include a method of adjusting dehydration conditions (number of suction boxes, number of hydrofoils, degree of vacuum, etc.) in the wire part; There is a method of combining papers made of more than one type of pulp with different disintegration states. Examples of methods for combining papers include a method of combining two types of wet paper, a method of joining papers together using an adhesive, and a method of welding them together using a heat press using a heat-melting substance.
The glass interleaving paper of this embodiment is obtained as described above.

[Laminated body]
The laminate 10 of this embodiment is a laminate 10 in which the above-mentioned glass interleaving paper 1 is interposed between a plurality of glass plates 2.

The glass plate laminate 10 shown in FIG. 1 has a structure in which five glass interleaving papers 1 and five glass plates 2 are alternately laminated. Note that the number of laminated sheets of glass interleaving paper 1 and glass plate 2 is not limited to this, and may be changed as appropriate depending on various conditions such as the strength and size of glass plate 2 and the size of the packaging container. The number of laminated glass plates may be two or more, and the upper limit is, for example, 300 or less. Usually, the laminates are stacked so that the total mass of the laminate 10 is 2000 kg or less.
The number of laminated sheets of glass plate 2 and glass laminated paper 1 is usually determined by whether the number of glass plate 2 and glass laminated paper 1 is the same, or the number of glass laminated paper 1 is one more than the number of glass plate 2. Either.

The use of the glass plate 2 is not particularly limited, but since the glass interleaving paper 1 of this embodiment generates particularly few particles, the glass plate 2 can be used for glass plates etc. used in the manufacture of semiconductor products. It is applied to glass plates whose surfaces are required to be kept highly clean, such as flat panel displays such as glass substrates for liquid crystal displays and glass substrates for plasma displays, organic EL lighting, and electronic devices such as solar cells. It is preferable that the glass plate is made of glass.

The material of the glass plate 2 is not particularly limited and may be appropriately selected depending on the application, and examples include soda lime glass, aluminosilicate glass, borosilicate glass, alkali-free aluminosilicate glass, and quartz glass. It is also possible to use a glass plate made of glass or tempered glass that absorbs ultraviolet and infrared rays.

The shape, size, thickness, etc. of the glass plate 2 are not particularly limited, and may be any shape, size, thickness, etc. that allows two or more sheets to be stacked and stored and transported.
The shape of the glass plate 2 may be, for example, a flat plate like the glass plate shown in FIG. 2, or may be a curved surface having a curvature on the entire surface or a part thereof.
The thickness of the glass plate 2 may be adjusted as appropriate depending on the application, and is, for example, 0.01 to 10 mm.
The size of the glass plate may be, for example, about the 8th generation (2200 mm x 2500 mm) developed in recent years. In this case, the thickness of the glass plate is preferably 0.2 to 0.8 mm from the viewpoint of ensuring strength, and more preferably about 0.3 to 0.7 mm.
Further, the glass plate 2 may be a laminated glass in which a plurality of glass plates are bonded with an interlayer interposed therebetween.

The manufacturing method of the glass plate 2 is not particularly limited either, but for example, it is formed to a predetermined thickness by a method such as a press method, a down-draw method, or a float method, and after being slowly cooled, it is processed by grinding, polishing, etc. to a predetermined size. , a glass plate having a shape may be used.

Further, the glass plate 2 may have a functional thin film on its surface. Specifically, functional thin films include conductive films (tin-doped indium oxide (ITO), zinc oxide (ZnO), tin oxide (SnO ₂ ), Ag, films having a Cr/Cu/Cr structure, etc.) and heat ray shielding films. A film (a layer having an oxide (eg, zinc oxide, titanium oxide, ITO, etc.)/Ag/oxide structure, etc.), etc. Here, zinc oxide may be doped with Al, Ga, hydrogen, or the like. Furthermore, tin oxide may be doped with F or Sb. Furthermore, Ag may be doped with Pd or Au.

[Package]
The package of this embodiment is a package that includes a packaging container and the laminate of this embodiment accommodated in the packaging container.
When transporting or storing glass plates, glass plates and glass interleaving paper are alternately laminated to form a laminate, which is then placed in a packaging container and then packed to form a package (glass plate package). . There are two types of glass plate packages: a horizontal type in which the glass plates are stacked horizontally, and a vertical type in which the glass plates are stacked in an inclined state, and the present invention can be applied to either type. FIG. 2 shows a schematic configuration of an example of a vertically stacked glass plate package. Further, FIG. 3 shows a schematic configuration of an example of a horizontally placed glass plate package.

In the glass plate package 30 shown in FIG. 2, a glass plate laminate 10 in which a plurality of glass plates 2 are laminated with a glass interleaving paper 1 interposed therebetween is packed in a packaging container 31. Note that the glass interleaving paper 1 is also placed between the packaging container 31 and the glass plate 2. The packaging container 31 is a well-known vertically stacked packaging container for glass plate packaging, and includes a base 33, an inclined table 32 erected on the top surface of the base 33, and a tilted table 32 placed on the top surface of the base 33. A mounting table 34 is provided.

One vertical surface (contact surface with the glass plate laminate 10; hereinafter also referred to as "slanted surface") of the inclined table 32 is inclined with respect to the vertical direction. The angle of this inclined surface (indicated by α in FIG. 2) may be any angle that allows the laminated glass plate laminate 10 to be stably loaded, stored, and transported, and is usually 85° with respect to the horizontal direction. or less, for example, 85° to 70°.

Moreover, the upper surface of the mounting table 34 is inclined so as to descend toward the inclined table 32 with respect to the horizontal direction. In the illustrated example, the upper surface of the mounting table 34 is configured to form an angle of 90 degrees with respect to the inclined surface of the inclined table 32, as an example.

In the packaging container 31 , the glass plates 2 are placed on the upper surface of the mounting table 34 and stacked against the inclined surface of the inclined table 32 . Further, a glass interleaving paper 1 is interposed between each glass plate. Further, the surface of the frontmost glass plate may be covered with glass interleaving paper.

In the glass plate package 50 shown in FIG. 3, a glass plate laminate 10 in which a plurality of glass plates 2 are laminated with glass interleaving paper 1 interposed therebetween is packed in a packaging container 51. Note that the glass interleaving paper 1 is also placed between the packaging container 51 and the glass plate 2. The packaging container 51 is a known packaging container for horizontally placed glass plate packaging, and includes a base 53 and a mounting base 54 placed on the upper surface of the base 53. Further, at the corners of the upper surface of the base 53 (for example, at least four corners if the upper surface of the base 53 is rectangular), there are struts 52 for stacking the packaging containers 51.

The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto.

<Manufacture of glass interleaving paper>
(Example 1)
Water is added to NBKP (virgin pulp ratio 100%) prepared as raw material pulp to form a slurry, aluminum sulfate (1 part by mass per 100 parts by mass of raw material pulp) is added to the bone-dry pulp, and then double The pulp was refined using a disc refiner until the CSF was reduced to 500 ml to obtain a pulp slurry. The obtained pulp slurry was made into paper using a Fourdrinier paper machine and a multi-tube dryer at a papermaking speed of 400 m/min to obtain the glass interleaving paper of Example 1.

(Example 2)
The glass interleaving paper of Example 2 was obtained in the same manner as in Example 1, except that 80% of NBKP (100% virgin pulp) and 20% of LBKP (100% virgin pulp) were used as the raw material pulp. Ta.

(Example 3)
Glass interleaving paper of Example 3 was obtained in the same manner as Example 1 except that LBKP (virgin pulp ratio 100%) was used as the raw material pulp.

(Examples 4 and 5)
Glass interleaving papers of Examples 4 and 5 were obtained in the same manner as in Example 2 except that the mixing ratio of NBKP and LBKP was changed as shown in Table 1.

( Reference example 6)
Glass interleaving paper of Reference Example 6 was obtained in the same manner as in Example 1 except that 80% of NBKP and 20% of waste paper pulp (DIP) were mixed and used as the raw material pulp.

(Example 7)
Glass interleaving paper of Example 7 was obtained in the same manner as Example 3 except that aluminum sulfate was not added.

( Reference example 8)
Water is added to NBKP (virgin pulp ratio 100%) to form a slurry, aluminum sulfate (1 part by mass per 100 parts by mass of raw material pulp) is added to the bone-dry pulp, and then a double disc refiner is used. Pulp slurry A was obtained by beating until the CSF was reduced to 500 ml. Further, pulp slurry B was obtained in the same manner as pulp slurry A except that the pulp slurry was beaten until the CSF became 550 ml. Pulp slurry A is introduced into the outer wire and pulp slurry B is introduced into the inner wire using a two-layer crescent former consisting of twin wires and a head box equipped with an injection port that can inject two types of raw materials without mixing them. Then, these were combined to form a two-layer paper, and the paper was passed through a Yankee dryer to obtain glass interleaving paper of Reference Example 8.

(Example 9)
Glass interleaving paper of Example 9 was obtained in the same manner as in Example 1 except that the papermaking speed was increased to 1.5 times.

(Comparative example 1)
A glass interleaving paper of Comparative Example 1 was obtained in the same manner as in Example 1 except that the paper was refined using a double disc refiner until the CSF became 30 ml (mainly free form refining).

(Comparative example 2)
Glass interleaving paper of Comparative Example 2 was obtained in the same manner as in Example 3, except that the pulp was refined using a double disc refiner until the weighted average fiber length of the pulp was 0.6 mm (mainly free beating). Ta.

( Reference Example 10, Comparative Example 3)
In Reference Example 10 and Comparative Example 3, low-grade glass interleaving paper with a virgin pulp ratio of less than 80% was produced.
Glass interleaving paper of Reference Example 10 was obtained in the same manner as in Example 1 except that 70% of LBKP and 30% of waste paper pulp were mixed and used as the raw material pulp.
Further, a glass interleaving paper of Comparative Example 3 was obtained in the same manner as in Example 1 except that only waste paper pulp was used as the raw material pulp.

<Evaluation of glass interleaving paper>
Regarding the glass interleaving paper of each example, the average fiber length of the disintegrated pulp, the content of fibers with a fiber length of 0.2 mm or more and 1.2 mm or less, and the content of fibers with a fiber length of more than 1.2 mm and 3.2 mm or less , the fibrillation rate was measured. In addition, the basis weight, thickness, Bekk smoothness, resin content, ash content, contact angle of water on the glass substrate surface after contact with the glass substrate, (R index), and particle generation amount were measured. The measurement method will be explained below. Moreover, the measurement results are shown in Tables 1 and 2.
In addition, for the measurement, in accordance with JIS P8111: 1998 "Paper, paperboard and pulp - standard conditions for humidity control and testing", the sample was left standing in air under standard conditions (23±1℃, 50±2RH%). The sample used was one in which humidity control had been completed and the moisture in the sample was in equilibrium with the water vapor in the test chamber under standard conditions.

(pulp disintegration)
JIS P8220-1:2012 "Pulp - Disintegration method - Part 1: Disintegration of chemical pulp" Using water purified to an electrical conductivity of 0.25 mS/m or less at 25°C, pulp is Dissociation was performed.
In Examples 1 to 5, 7, and 9, Reference Examples 6 and 10, and Comparative Examples 1 and 2, glass interleaving paper torn into a size of about 25 mm x 25 mm was added to 2000 ± 25 mL of water at 20 ± 5 ° C. In addition to using a disintegrator, disintegration was performed until the fibers were completely dispersed to obtain disintegrated pulp.
In Reference Example 8, the glass interleaving paper was divided in the thickness direction to separate only the area near the surface, and this was torn into a size of approximately 25 mm x 25 mm, added to 2000 ± 25 mL of water at 20 ± 5 ° C, and placed in a standard disintegrator. In addition, disintegration was performed until the fibers were completely dispersed to obtain disintegrated pulp. The glass interleaving paper was divided using a transparent tape whose base film was polyester and an acrylic resin adhesive, and repeated application and peeling of the tape until the thickness reached 10 μm.

(Average fiber length [mm] of disintegrated pulp, content rate [%] of fibers whose fiber length is 0.2 mm or more and 1.2 mm or less and fiber length more than 1.2 mm and 3.2 mm or less, fibrillation rate [%] )
The average fiber length and fiber length classification/distribution of the obtained disintegrated pulp were measured using a fiber image analyzer (Valmet FS5, manufactured by Valmet), and the fiber length was determined to be between 0.2 mm and 1.2 mm. The content of fibers having the following values and the content of fibers having a fiber length of more than 1.2 mm and less than 3.2 mm were determined, and the fibrillation rate was measured. Note that the ISO fiber length range (0.20 to 7.0 mm) was adopted for the measurement, and the average value of the values measured five times for each sample was used.

(Basic weight [g/m ² ])
The basis weight of the glass interleaving paper of each example was measured in accordance with JIS P8124:2011 "Paper and Paperboard - Method for Measuring Basis Weight."

(Thickness [μm])
The thickness value of the glass interleaving paper of each example was measured in accordance with JIS P 8188:2014 "Paper and paperboard - Test method for thickness, density and specific volume".

(Bekk smoothness [seconds])
The Bekk smoothness of the glass interleaving paper of each example was measured by the method specified in JIS P8119:1998 "Paper and paperboard - Smoothness test method using Bekk smoothness tester".

(Resin content [%])
The amount of substance (resin content) extracted with acetone from the glass interleaving paper of each example was measured by the method specified in JIS P8224:2002 "Pulp - Acetone Soluble Content Test Method".

(ash[%])
The amount of residue ( Ash content) was measured.

(Contact angle [deg] of water on the surface of the glass substrate after contact with the glass substrate, amount of particles)
First, the glass substrate was washed with an alkaline liquid such as a 5% NaOH aqueous solution to remove organic and inorganic contamination from the surface, and then dried with CDA (clean dry air). Next, a glass interleaving paper was placed on this glass substrate, a surface pressure of 3 kPa was applied, and the temperature was kept at 80°C and 60RH% for 24 hours in a constant temperature bath (the temperature was increased from 25°C and 50RH% for 5 hours). , the temperature was lowered to 25°C and 50RH% over 5 hours). Thereafter, the glass interleaving paper was removed from the glass substrate.
Thereafter, the contact angle of water on the surface of the glass substrate on which the glass interleaving paper was placed was measured. In addition, the glass substrate was measured in standard sensitivity mode using a foreign matter inspection device for FPD (HS-830 manufactured by Toray Engineering Co., Ltd.) to count the number of particles. Thereafter, a value (particle amount index) was calculated by dividing the number of particles measured in each example by the number of particles measured in Example 1. Note that the number of particles in Example 1 was used as the reference because the number of particles in Example 1 was the smallest.

(R index)
A glass interleaving paper was placed on a white plate, and a glass substrate with a thickness of 0.5 mm was placed on top of it. An area camera is placed vertically above this glass substrate, and from a line-shaped illumination placed at an angle of 30 degrees from the camera, an amount of light is emitted that gives an illuminance of 3,000 Lux when measured at a distance of 5 mm from the illumination light emission. Images were acquired with a camera while irradiating. The acquired image was image-processed to extract points with large variations in gradation value relative to the surroundings, and the value obtained by dividing the number of such points by the number of pixels of the entire paper was defined as the R index. The point where the gradation value fluctuates greatly is the point where ABS ((average gradation value in the range of ±10 pixels surrounding the pixel)−(gradation value of the pixel))>2.

In the glass interleaving paper of Comparative Example 1, the fibrillation rate of the disintegrated pulp obtained by disintegrating the glass interleaving paper was high, and therefore the amount of particles was large.
In the glass interleaving paper of Comparative Example 2, the fibrillation rate of the disintegrated pulp obtained by disintegrating the glass interleaving paper was high, and the average fiber length was short, so the amount of particles was large.
On the other hand, in Examples 1 to 5, 7, and 9, the average fiber length of the disintegrated pulp obtained by disintegrating glass interleaving paper was 0.7 to 2.5 mm, and the fibrillation rate was 0.3 to 3%. , and the glass interleaving paper of Reference Example 6 had a small amount of particles. Furthermore, even with the glass interleaving paper of Reference Example 8, in which the average fiber length of the disintegrated pulp obtained by disintegrating the area near the surface is 0.5 to 3.5 mm, and the fibrillation rate is 0.1 to 4%, particles The quantity was small.

Comparing Reference Example 10, which is a low-grade glass interleaving paper, with Comparative Example 3, the glass interleaving paper of Comparative Example 3, in which the average fiber length of the disintegrated pulp obtained by disintegrating the glass interleaving paper is short, has a remarkable amount of particles. There were many.
On the other hand, in the glass interleaving paper of Reference Example 10, in which the average fiber length of the disintegrated pulp obtained by disintegrating the glass interleaving paper is 0.7 to 2.5 mm, and the fibrillation rate is 0.3 to 3%, the particle The quantity was relatively small.

1 Glass interleaving paper; 2 Glass plate; 10 Laminated body; 30 Packing body; 31 Packing container; 32 Inclined table; 33 Base; 34 Mounting table; 50 Packing body; 51 Packing container; 52 Support column; 53 Base; Stand.

Claims (11)

A glass interleaving paper interposed between glass plates,
A glass interleaving paper, wherein the length-weighted average fiber length of the disintegrated pulp obtained by disintegrating the glass interleaving paper is 0.7 to 2.5 mm, and the fibrillation rate is 0.3 % or more and less than 2% . The glass interleaving paper according to claim 1 , having a virgin pulp ratio of 80% or more. The glass interleaving paper according to claim 1 or 2, which has a basis weight of 20 to 100 g/m ² , a thickness of 30 to 150 μm, an ash content of less than 0.15% by mass , and a resin content of 0.5% by mass or less . The glass interleaving paper according to any one of claims 1 to 3 , wherein the content of fibers having a fiber length of more than 1.2 mm and 3.2 mm or less in the disintegrated pulp is 40% by mass or more. The glass interleaving paper according to any one of claims 1 to 4 , wherein the content of fibers having a fiber length of 0.2 mm or more and 1.2 mm or less in the disintegrated pulp is 40% by mass or more. The glass interleaving paper according to any one of claims 1 to 5 , wherein the contact angle of water on the surface of the glass substrate after the glass interleaving paper is brought into contact with the glass substrate is 20 ° or less. The glass interleaving paper according to any one of claims 1 to 6 , having an R index of 0.4 or less. The glass interleaving paper according to any one of claims 1 to 7 , which has a rectangular shape and has at least one side length of 500 mm or more. A laminate in which the glass interleaving paper according to any one of claims 1 to 8 is interposed between a plurality of glass plates. The laminate according to claim 9 , wherein the glass plate has a thickness of 0.1 to 1.5 mm. A package comprising a packaging container and the laminate according to claim 9 or 10 accommodated in the packaging container.

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