TWI679154B - Glass sheet - Google Patents

Abstract

Provided is a glass plate spacer which can reduce wrinkle-like contamination on the surface of a glass plate and which can be manufactured even by ordinary manufacturing equipment. A kind of glass plate spacer paper, characterized in that wood pulp is used as the main component, the longitudinal tensile elasticity coefficient is 7.1 GPa or less, the transverse tensile elasticity coefficient is 4.0 GPa or less, and the unit area weight is 30 to 60 g / m ² The air permeability is below 11 seconds / 100ml. The resin content of the glass plate spacer is preferably 0.10% by mass or less.

Description

Glass sheet

The present invention relates to a glass plate spacer which is used between glass plates and glass plates.

In order to protect the glass plate, a glass plate spacer paper is used in the circulation process or manufacturing process of stacking a plurality of so-called touch panels, displays, or flat panel panels, and glass panels for displays.

A glass plate that is used as a substrate material for a panel display requires higher surface smoothness than a general building window glass plate or a vehicle window glass plate. The glass plate for panel displays is formed as a thin film on the surface of the glass plate, and therefore, the glass plate has a higher degree of cleanliness and surface flatness than glass plates used for other purposes. When a glass plate of such a use is in contact with other glass plates, even if it is slightly damaged or contaminated, the performance as a display may be broken.

In addition, with the increase in the size and mass production of glass sheets, as a countermeasure to improve the conveyance efficiency, a measure of conveyance was adopted by superimposing glass sheets. Therefore, there is a tendency to increase the contact area with the glass sheet . When the contact area or contact pressure between the glass sheet and the glass sheet is increased, the possibility of a flaw on the surface of the glass sheet is increased due to the presence of foreign matter in the glass sheet. In addition, the transfer of resin components and the like contained in the glass sheet spacer paper also increases the possibility of contaminating the surface of the glass sheet.

Therefore, high quality is required for the glass plate spacer paper inserted between the glass plate and the glass plate.

In order to reduce the damage or contamination caused by the glass sheet spacer, for example, Patent Document 1 discloses a glass sheet spacer using a slurry raw material as a main component. The glass sheet spacer has a weight per unit area of 30 to 60 g / m ² , a maximum paper thickness difference between adjacent measurement points is 8 μm or less, and a difference between a maximum value and a minimum value of the paper thickness is 16 μm or less. .

Patent Document 2 discloses that by arranging the slurry, the compression workload is 0.15 J / m ² or more, and the compression recovery rate is 50% or more, which improves cushioning properties and suppresses damage to the surface of the glass plate. Resulting technology. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2009-184704 [Patent Document 2] Japanese Patent Laid-Open No. 2006-44674

The foregoing prior art attempts to improve the physical properties and forms of glass sheet spacers to prevent injury, improve adhesion, prevent pollution, and the like. However, since it is necessary to increase the manufacturing process or new raw materials or specific manufacturing equipment, there is still room for improvement in terms of manufacturing management or productivity.

However, when sodium ions or calcium ions in the glass component dissolve out of the water in the glass sheet, it reacts with carbon dioxide in the air to produce sodium carbonate or calcium carbonate. When this sodium carbonate or calcium carbonate is precipitated on the surface of a glass plate, it becomes wrinkled (wrinkled) -like white turbidity that is not easily dropped even when washed, and it may cause contamination on the surface of the glass plate.

The present invention has been made in view of such circumstances. An object of the present invention is to provide a glass plate spacer which can reduce wrinkle-like contamination on the surface of a glass plate, and which can be manufactured even by ordinary manufacturing equipment.

The present inventors focused on the wrinkle-like contamination on the surface of the glass plate, and reviewed the countermeasures. As a result, it was found that the contamination can be improved by reducing the glass sheet spacer paper to a prescribed coefficient of tensile elasticity. That is, the present invention has the following structure.

(1): A kind of spacer paper for glass plate, which is characterized in that wood pulp is used as the main component, the longitudinal tensile elastic coefficient is below 7.1 GPa, the transverse tensile elastic coefficient is below 4.0 GPa, and the unit area weight is 30 ~ 60g / m ² , air permeability is 11 seconds / 100ml or less.

(2) The glass sheet spacer according to the above (1), wherein the resin content is 0.10% by mass or less.

(3) The glass sheet spacer according to the above (1) or (2), characterized in that the density is 0.55 to 0.75 g / cm ³ .

(4) The glass sheet spacer according to any one of (1) to (3), characterized in that the impregnated freeness of the aforementioned wood pulp system measured in accordance with JIS P8121: 2012 is 350-550 ml.

The glass plate spacer paper of the present invention can reduce wrinkle-like contamination on the surface of the glass plate, and can be manufactured even with ordinary manufacturing equipment.

Hereinafter, embodiments of the present invention will be specifically described. It should be noted that the present invention is not limited to these embodiments.

The present inventors first reviewed the situation of wrinkle-like contamination of glass plates. As a result, it became clear that when a wrinkle is generated in the glass sheet, the wrinkle-like stain is generated along the wrinkle. In other words, when the wrinkled portion of the glass plate spacer paper is strongly pressed against the glass plate, sodium carbonate or calcium carbonate generated in the glass plate spacer paper is transferred to the glass plate surface, causing wrinkle-like contamination.

Therefore, when examining the cause of wrinkles in the glass sheet, the following was clearly understood. When the glass spacer paper is sandwiched between the glass plate and the glass plate, the glass spacer paper will absorb and desorb moisture in the air, causing the paper to expand and contract. When the glass sheet is strongly pressed against the glass sheet, it is possible to suppress the expansion and contraction of the paper and to cause a state of accumulation and skewness. However, in the distribution process or manufacturing process, when the pressure of the glass sheet pressing the glass sheet spacer paper is reduced, the accumulated distortion is released and returned to the original state. As a result, the paper expands and contracts irregularly, and the paper is spaced between the glass plates, causing wrinkles.

Next, the relationship between the occurrence of wrinkled contamination and the coefficient of tensile elasticity of the glass sheet spacer paper is further reviewed. It is clearly known that when reviewing the production of glass sheet spacer papers with different tensile elastic coefficients and the occurrence of wrinkle-like contamination of glass plates, glass sheet spacer papers with low tensile elastic coefficients are higher than Glass sheet spacers are also less prone to wrinkle-like contamination. It is presumed that during the time when the glass plate is strongly pressed against the glass sheet, when the accumulated skew is released, the glass sheet with high tensile modulus of elasticity has a stronger force to return to the original state, and it is easy to produce wrinkles.

The glass plate spacer paper is generally continuously produced industrially using a papermaking machine. Therefore, in general, glass sheet paper is anisotropic. The longitudinal direction (mechanical direction, the direction of paper in the machine) is more flexible than the horizontal direction (a right angle to the mechanical direction). Smaller and more difficult to accumulate skew. When investigating the occurrence of wrinkle-like contamination of glass plates, most of the wrinkles occurred in the longitudinal direction of the glass plate spacer paper. It is presumed that this is because the paper's horizontal direction is relatively easy to accumulate skew. Therefore, when the paper is returned to its original state when the skew is released, wrinkles occur in the longitudinal direction of the glass spacer paper due to the strong recovery of the horizontal direction. Therefore, in order to suppress wrinkles, it is required to further reduce the coefficient of tensile elasticity in the lateral direction.

When assessing the results of the above review, as a glass sheet spacer that can reduce the occurrence of wrinkled contamination, the longitudinal tensile modulus of elasticity must be 7.1 GPa or less, and the transverse tensile modulus of elasticity can be 4.0 GPa or less. The tensile modulus of elasticity in the longitudinal direction is preferably below 6.7 GPa, and the tensile modulus of elasticity in the transverse direction is preferably below 3.6 GPa. On the other hand, when considering the processability during use, the tensile elastic modulus in the longitudinal direction is preferably 4.0 GPa or more, and the lateral tensile elastic modulus is preferably 2.0 GPa or more.

The coefficient of tensile elasticity is measured by using a tensile tester as described later. In order to control the longitudinal tensile elasticity coefficient and transverse tensile elasticity coefficient of glass plate spacer paper in a specified range, for example, the freeness of wood pulp, the unit weight of glass plate spacer paper, and the glass plate interval can be adjusted appropriately. Density of paper, finishing conditions of medicines and glass spacer paper etc.

The glass sheet spacer of this embodiment is made of wood pulp as a main component. Here, the term “wood slurry” as a main component refers to a wood slurry containing 50% by mass or more with respect to the entire mass of the glass sheet spacer. The content of the wood pulp is preferably more than 80% by mass, and more preferably more than 90% by mass. The wood pulp system can be used by mixing one or two or more kinds of various components. Examples of the wood pulp system include chemical pulps such as kraft pulp (KP), sulfite pulp (SP), and soda pulp (AP); semi-chemical pulp (SCP), and chemical mechanical wood pulp (CGP). Semi-chemical pulp; mechanical pulp of ground wood pulp (GP), thermomechanical pulp (TMP, BCTMP), homogenizer, chemical mechanical wood pulp (RGP), etc. In addition to these, a synthetic slurry, a synthetic fiber, a rayon fiber, and the like may be blended as necessary. The wood used in the wood slurry can be coniferous or hardwood, and can also be mixed and used. Typical wood pulp systems include sassafras bleached kraft pulp (LBKP) and conifer bleached kraft pulp (NBKP).

The wood pulp system has a immersion freeness (beating degree) measured in accordance with JIS P8121: 2012 of preferably 350 to 550 ml. Here, the so-called impregnation freeness is measured in accordance with JIS P8121: 2012, and the Canadian standard freeness of the paper pulp impregnated with papermaking in accordance with JIS P8220-1 is measured. By immersion freeness, it can be in the range of 350 to 550ml, which can reduce the coefficient of tensile elasticity of glass plate spacer paper, and has mechanical strength and processability suitable as glass plate spacer paper. In addition, it can reduce the coefficient of tensile elasticity by being 350 ml or more, and effectively suppress the occurrence of wrinkles. On the other hand, it is possible to increase the tensile strength by making it 550 ml or less, and it is not easy to break the paper during operation. The immersion freeness is more preferably 450-550ml. In order to adjust the immersion freeness from 350 to 550 ml, a conventional method can be used as a method for beating the wood slurry.

The basis weight of the glass plate spacer is in the range of 30 to 60 g / m ² . The weight per unit area of the glass plate spacer paper is more preferably 40 to 50 g / m ² . When the basis weight is less than 30 g / m ² , sufficient cushioning properties and handling properties cannot be provided. In addition, when the weight per unit area exceeds 60 g / m ² , the load during transportation becomes large, which is not desirable. The measurement of the basis weight of the glass plate spacer is performed in accordance with JIS P8124: 2011.

From the viewpoints of processability and volume, the density of the glass plate spacer is preferably 0.55 to 0.75 g / cm ^{3, more} preferably 0.55 to 0.70 g / cm ³ , and 0.60 to 0.70 g / cm ^3. Better. From the viewpoints of handleability and volume, the thickness of the glass plate spacer is preferably 40 to 100 μm, and more preferably 50 to 90 μm. The measurement of the thickness and density of the glass plate spacer is performed in accordance with JIS P8118: 2014.

The air permeability of glass sheet spacer paper is 11 seconds / 100ml or less. When the air permeability of the glass sheet spacer paper exceeds 11 seconds / 100ml, there is a situation that the glass and the glass sheet spacer paper are more closely adhered and the glass pollution is promoted. In addition, when the glass and the glass sheet spacer paper are sucked up by vacuum suction at the same time, only the glass sheet spacer paper is sucked up to reduce the working efficiency. The air permeability of the glass sheet spacer paper is preferably 7 seconds / 100ml or less. The measurement of the air permeability was performed in accordance with JAPAN TAPPI-5 by a measurement method using a Gurley tester. The air permeability of the glass sheet spacer paper can be controlled by adjusting the weight and density of the glass sheet spacer paper.

The resin component contained in the glass plate spacer paper becomes a contaminant on the surface of the glass plate. Many of them are natural impurities such as resins contained in wood, and most of them are adhesive substances. Therefore, from the viewpoint of preventing contamination of the glass plate, the amount of resin in the glass plate spacer is preferably 0.10% by mass or less, and more preferably 0.09% by mass or less. Examples of the method for obtaining glass spacer paper with a small amount of resin include: a method of selecting and using wood with a small amount of pitch retention, a method of strengthening pulp washing after steaming or bleaching, and using a permeate wire for the pulp pulp. A method of using a slurry obtained by performing a dehydration treatment, a method of using a slurry obtained by dewatering a sheet of the slurry by pressing a roll press with a roll, and the like.

In the glass sheet spacer paper of this embodiment, the conventionally-applied medicine can be appropriately added in a range where the glass sheet surface does not cause contamination or scratches. Examples of internal medicines include fillers such as rosin, alkenyl succinic anhydride, and alkylketene dimer, fillers such as titanium dioxide, kaolin, talc, and calcium carbonate, paper strength enhancers, yield improvers, pH adjuster, water-repellent enhancer, water-resistant agent, softener, antistatic agent, defoamer, sizing agent, dye, pigment, etc. In addition, the surface and the back surface of the glass sheet may be coated or impregnated with water, a glass cleaner, or the like in addition to the aforementioned chemicals.

Among the enclosed medicines, various resins such as polypropylene amidamine, cationic starch, various modified starches, urea resins, polyamide-polyamine resins, polyvinyl alcohol, and polyethylene oxide are used as paper strength enhancers. . In this embodiment, from the viewpoint of preventing glass contamination, the content of the paper strength enhancer is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less.

Among the enclosed medicines, as the pH adjuster, alumina sulfate (aluminum sulfate), aluminum chloride, sulfuric acid, hydrochloric acid, soda aluminate, basic aluminum compounds, sodium hydroxide, potassium hydroxide, ammonia, various Amine, etc. In this embodiment, from the viewpoint of preventing paper powder contamination from a papermaking machine, a glass sheet containing aluminum sulfate is preferred. The content of aluminum sulfate is preferably 0.2% by mass or more, and more preferably 0.3 to 1.0% by mass.

As a means for coating or impregnating the aforementioned medicines, for example, a two-press roll size punch, a transfer press roll applicator (brake press applicator, Massey applicator, KCM applicator, Champion mechanical applicators, etc.), film transfer size punches (gap classifiers, blade metering size punches, etc.), Bill blade coaters (standard applicators, differential applicators, comprehensive applicators) , Two-pass coater, BEL-BAPA coater, bar coater, blade coater, air knife coater, rod coater, calender coater, etc.

The manufacturing apparatus and manufacturing conditions for manufacturing the glass plate spacer of this embodiment are not particularly limited, and a conventional manufacturing apparatus and manufacturing conditions can be appropriately selected and used. For example, a single-layer or multi-layer paper can be formed by a fourdrinier former, a two-wire former, a cylinder former, or an inclined former to perform papermaking. In addition, the texture can be adjusted moderately, and an embossing roller is used for the purpose of controlling the smoothness of the paper surface and the uniformity in the width direction.

The glass plate spacer paper of this embodiment can be subjected to embossing processing or wrinkling processing with fine unevenness on the surface. The embossing process is performed using a pattern embossing machine, a concave-convex mold, or the like, and has a shape such as a dot shape, a chain line shape, a linear shape, or a wave shape. As a series of methods for performing the wrinkle treatment, a method of wrinkling is carried out by peeling off the adhered sheet by a blade provided on a press roller or a dryer of a wet part of a paper machine. [Example]

Hereinafter, the present invention will be described in detail by examples. However, the present invention is not limited by these examples. In addition, the numerical value shown as a formula is a numerical value of the mass standard of a solid component or an active ingredient. In addition, in particular, a paper system in which papermaking is performed in an undocumented state is processed in accordance with JIS P8111: 1998 and then supplied for measurement and testing. (Example 1)

100% pulp of LBKP (Bleafwood Bleached Kraft Pulp) sold on the market by a two-disc refiner was beaten until the immersion freeness became 470 ml. The obtained slurry was subjected to papermaking and drying by a Fourdrinier paper machine to obtain a glass plate spacer paper having a weight per unit area of 46.8 g / m ² and a density of 0.64 g / cm ³ . (Example 2)

Except that the pulp becomes 81% of LBKP sold on the market and 19% of NBKP (coniferous bleached kraft pulp) on the market, and the impregnation freeness becomes 550ml, the rest is the same as in Example 1, and the weight per unit area is 42.9g / M ² , 0.65g / cm ³ glass sheet spacer paper. (Example 3)

Except that the immersion freeness was 390 ml, the rest was the same as in Example 1, and a glass plate spacer having a basis weight of 42.0 g / m ² and a density of 0.67 g / cm 3 was obtained. (Comparative Example 1)

Except that the immersion freeness was 434 ml, the rest was the same as in Example 1, and a glass plate spacer having a basis weight of 46.6 g / m ² and a density of 0.75 g / cm ³ was obtained. (Comparative Example 2)

In addition to the pulp body become commercially trafficking and 50% of the market selling LBKP pulp mixture thereof, 50% of the impregnated freeness 405ml become NBKP, the rest of the same system as in Example 1, to give a basis weight of 55.0g / m ^2, a density of 0.70g / cm ³ glass plate spacer. (Comparative Example 3)

Except that the immersion freeness was 424 ml, the rest was the same as in Example 1, and a glass plate spacer having a basis weight of 50.3 g / m ² and a density of 0.68 g / cm ³ was obtained.

The evaluation method of the obtained glass plate spacer is as follows. <Immersion Freeness>

The measurement was performed in accordance with JIS P8121-2: 2012. ＜ Weight per unit area ＞

The measurement was performed in accordance with JIS P8124: 2011. <Density>

The measurement was performed in accordance with JIS P8118: 2014. ＜ Measurement of resin content ＞

Generally, the measurement is performed in accordance with ISO624-1974, which is a method for measuring the amount of resin present in a slurry. Soxhlet extraction was performed on a glass plate spacer paper with absolute dryness of about 10 g as a sample, dichloromethane as a solvent, and a constant temperature heater for 4 hours, by the following formula 1 Then, the amount of resin m in the paper is determined.

Formula 1: m = (m0 / m1) × 100 m: resin amount (% by mass) m0: dichloromethane extract (g) m1: absolute dry mass of the sample (g) <air permeability>

The measurement was performed in accordance with JAPAN TAPPI-5 by the Gurley tester method. ＜ Smoothness ＞

In accordance with JAPAN TAPPI No. 5-2: 2000, the W surface (line surface) and F surface (front surface) of the glass sheet spacer were measured using a Wang Yan-type smoothness meter. ＜ Tensile strength and coefficient of tensile elasticity ＞

In accordance with JIS P8113: 2006, the tensile strength and the coefficient of tensile elasticity of the glass sheet spacer paper were measured in the longitudinal and transverse directions. Regarding the tensile strength, the relative ratio between the longitudinal direction and the transverse direction was determined. <Crem-type water absorption>

According to JIS P8141: 2004, it measured about the longitudinal direction and the horizontal direction of the glass plate spacer. The lower end of the paper was immersed vertically in water, and the height (mm) of the water was raised by the capillary phenomenon over 10 minutes and measured. ＜ Glass pollution promotion test ＞ (Test conditions)

Between the two glass plates (floating glass: manufactured by Asahi Glass Co., Ltd., 200mm × 200mm × 3mm thickness), sandwich the glass plate spacer paper and place it on a horizontal table. A 10kgf weight was placed on a glass plate, placed in a high-temperature and high-humidity tank, and left to stand for 4 days.

Weight: 0.025 kgf / cm ² Temperature: 60 ° C Humidity: 95% RH Weight: 4 days (96 hours) (Evaluation method)

After 4 days, take out from the high-temperature and high-humidity tank, remove the weight, and sandwich the two glass plates with a glass plate interval paper. Observe the occurrence of wrinkles by visual inspection. And evaluate.

5: No wrinkles are observed at all 4: Only slight wrinkles are generated 3: Several fine wrinkles are generated 2: Several coarse wrinkles are generated 1: Many thick wrinkles are generated

Next, the two glass plates were removed, and the glass plate spacer was taken out. Without cleaning the glass plate, blow the steam inside the glass plate (the glass plate is separated from the paper side). The degree of contamination that appeared was observed visually, and evaluated based on the following criteria.

5: No wrinkle-like pollution is observed at all 4: Only slight wrinkle-like pollution is generated 3: Several fine wrinkle-like pollution is generated 2: Several coarse wrinkle-like pollution is generated 1: Many coarse wrinkle-like pollution is generated

Table 1 shows various evaluation results of the glass plate spacers of Examples 1 to 3 and Comparative Examples 1 to 3.

[Table 1]

The glass-sheet spacer papers of Examples 1 to 3 have low tensile elastic coefficients in the longitudinal and transverse directions, and a small air permeability value. In the test for promoting glass pollution, there are fewer wrinkles and less wrinkle-like pollution. Its performance.

On the other hand, the tensile elastic modulus of the glass sheet spacer of Comparative Example 1 in the transverse direction is slightly higher. In addition, since the value of the air permeability is high, the glass sheet is adhered to the glass. Therefore, in the test for promoting glass contamination, a large number of coarse wrinkles are generated on the glass sheet, and a large number of coarse wrinkles are generated on the glass sheet. In addition, the numerical value of the air permeability of Comparative Example 2 is slightly higher, and the elastic coefficient of Comparative Example 3 is slightly higher in the longitudinal direction. Therefore, in the test for promoting glass contamination, several rough wrinkles are generated in the glass sheet spacer paper. , All produced several thick wrinkle-like pollution.

Claims (4)

A kind of glass plate spacer paper, characterized in that wood pulp is used as the main component, the longitudinal tensile elasticity coefficient is 7.1 GPa or less, the transverse tensile elasticity coefficient is 4.0 GPa or less, and the unit area weight is 30 to 60 g / m ² The air permeability is below 11 seconds / 100ml. For example, the glass sheet spacer paper of the first patent application range, wherein the resin content of the glass sheet spacer paper is 0.10% by mass or less. For example, the glass sheet spacer paper of item 1 or 2 of the patent application scope, wherein the density of the glass sheet spacer paper is 0.55 to 0.75 g / cm ³ . For example, the glass sheet spacer paper of the scope of application for item 1 or 2, in which the aforementioned wood pulp system has an impregnation freeness measured in accordance with JIS P8121: 2012 of 350 ~ 550ml.