JP2009179379A - Slip sheet for glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an slip sheet for glass which is used by inserting between glass sheets needing high surface property and can prevent a surface of the glass sheet from being blemished by a foreign substance or the like existing on the boundary of the glass sheet and the slip sheet when the glass sheets with the slip sheet inserted are conveyed and which can be reused as a high quality pulp raw material for various applications. <P>SOLUTION: In the slip sheet for glass, the weight average fiber length of disintegrated pulp of the slip sheet for glass disintegrated based on JIS P 8220 is 1.0 mm or more and less than 1.6 mm and the micro-topography of both surfaces is 7.0 μm or less under pressurization condition of 23 kgf/cm<SP>2</SP>and the water-disintegration property based on JIS P 4501 is 180 seconds or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention is a slip sheet that is inserted and used between glasses that require a high degree of surface property, and preferably is inserted and used between glass substrates used in flat panel displays such as liquid crystal televisions and plasma televisions. It is related to the interleaving paper, and it can prevent the glass surface from being damaged by foreign matters existing at the boundary between the glass (substrate) and the interleaving paper when transporting with the interleaving paper inserted, and high quality The present invention relates to a glass interleaving paper that can be reused for various uses as a raw material for pulp.

  Conventionally, as a slip sheet for glass that is inserted between glasses and used, double-sided renewal paper or the like has been used mainly for the purpose of preventing scratches caused by rubbing between glasses. Further, in recent years, quality requirements for glass slip sheets have become severe due to diversification of glass. For example, glass substrates used in flat panel displays such as liquid crystal televisions and plasma televisions have a high degree of cleanliness and surface flatness required for the glass surface because electronic members are coated on the glass surface. Quality requirements for slip sheets are becoming stricter. Furthermore, as glass substrates become larger and mass-produced, the glass substrates are transported in layers as much as possible in order to increase transport efficiency, and exist at the boundary between the glass substrate and interleaf when the glass substrate is laterally displaced. The occurrence of scratches due to foreign substances such as glass powder is becoming a problem.

  In order to prevent contamination and scratches on the glass surface, slip sheets used for glass substrates used in flat panel displays, etc. have been controlled for internal chemicals and pulp raw materials so that the resin content in the paper can be reduced. A proposal to reduce the density as much as possible is disclosed (Patent Document 1). However, it has been difficult to cope with the lateral misalignment that occurs during the conveyance of the glass substrate, and there has been a demand for a glass slip sheet that has good adhesion to the glass substrate and has cushioning properties.

On the other hand, since the use amount of the glass slip sheet is increasing due to the mass production and enlargement of the glass substrate, there is a problem in the storage place and the processing method of the used glass slip sheet. However, glass interleaving paper is composed of a pulp material having a lower resin content, and can be reused for a wide range of uses as a virgin pulp material having a high purity. Therefore, paying attention to the excellent recyclability, after the used glass slip paper is generated, it is disaggregated and pulped, that is, the volume can be reduced, and the above problem can be solved by using as raw material pulp. There is also a demand for glass slip sheets that are excellent not only in quality requirements but also in excellent disaggregation after use.
JP 2006-44674 A

  The main problem to be solved by the present invention is a slip sheet that is inserted and used between glasses that require a high degree of surface property, and among them, glass that is preferably used for flat panel displays such as liquid crystal televisions and plasma televisions. Regarding interleaving paper inserted and used between the substrates, it is possible to prevent the glass surface from being damaged by foreign matter existing at the boundary between the glass (substrate) and interleaving paper when transporting with the interleaving paper inserted. Another object of the present invention is to provide a glass interleaving paper that can be reused for various purposes as a high-quality pulp raw material.

The present invention that has solved this problem is as follows.
[Invention of Claim 1]
A slip paper for glass mainly composed of pulp raw material,
The pulp raw material is mainly composed of NBKP and LBKP, and the blended mass ratio (NBKP / LBKP) of the disintegrated pulp of the glass interleaving paper disaggregated according to JIS P 8220 is 15/85 to 50/50,
The weight average fiber length of the disaggregated pulp of the glass interleaving paper disaggregated according to JIS P 8220 is 1.0 mm or more and less than 1.6 mm,
The average Runkel ratio of the disaggregated pulp of the glass interleaving paper disaggregated according to JIS P 8220 is 0.60 to 0.9,
Single-sided or double-sided microtopograph is 2.0 μm to 7.0 μm under a pressure of 23 kgf / cm ² ,
The water decomposability (ease of loosening) in accordance with JIS P 4501 is 180 seconds or less ,
A slip sheet for glass , wherein a glossy surface is formed on one side by a Yankee dryer .

[Invention of Claim 2 ]
The pulp raw material contains 0.01 to 0.50 mass% of a wetting improver having at least a polyoxyalkylene fatty acid ester ,
The slip sheet for glass according to claim 1 .

  According to the present invention, a slip sheet that is inserted and used between glasses that require a high degree of surface property, and among them, is preferably inserted between glass substrates used in flat panel displays such as liquid crystal televisions and plasma televisions. The interleaving paper that is used, and prevents the glass surface from being damaged by foreign matter, etc. existing at the boundary between the glass (substrate) and the interleaving paper when transported with the interleaving paper inserted, and high quality It becomes a glass slip sheet that can be reused for various applications as a raw material for pulp.

Next, an embodiment of the present invention will be described.
The slip paper for glass of this form has a pulp raw material as a main component. Although the kind of the pulp raw material is not particularly limited, bleached kraft pulp (NBKP, LBKP) in which bleaching treatment is performed and the resin content is controlled to be low is suitable for glass that requires high cleanliness. As a pulp raw material, the use of used paper recycled pulp (generally called DIP) made of used paper is also considered, but if there is a large amount of resin contained in the paper, polar organic substances strongly adhere to the silanol groups on the glass surface due to hydrogen bonding, On top of that, a hydrocarbon-based organic layer is formed by van der Waals force, which may contaminate the glass surface. In paper measured according to the method of measuring the amount of resin present in ISO624-1974 pulp It has been reported that if the resin content contained in the glass exceeds 0.2%, the glass surface is likely to be contaminated, so that it must be suppressed to 0.2% or less (for example, JP-A-2006 2006). (See paragraph 0028 of No. 44746). Therefore, when using DIP, after removing impurities contained in waste paper and further disaggregating, using an alkali or other chemicals, the ink film composed of inorganic substances and resin components is removed from the pulp fiber, and the surfactant is used. It is preferable to use a DIP obtained by collecting it in a similar manner and separating and removing it from the fiber.

  In addition, considering the function of preventing scratches on the glass surface when it is in close contact with glass, transportability, and contamination resistance, the weight average fiber length of the disintegrated pulp of the glass interleaving paper disaggregated according to JIS P 8220 is 1. The pulp raw material treated by beating or classification means is blended so that the weight average fiber length is preferably 1.30 mm or more and less than 1.50 mm so that the weight average fiber length is 1.0 mm or more and less than 1.6 mm.

  The weight average fiber length referred to in the present invention is a weight average fiber length measured using a Kayani fiber length measuring machine (FS-100) for disaggregated pulp after disaggregation according to JIS P 8220, and the unit is mm. It is.

  In adjusting the fiber length in this way, the main components of the pulp raw material are NBKP and LBKP, and the blending ratio (NBKP / LBKP) is disaggregated according to JISP8220, and the fiber composition test according to JIS P8120. Depending on the method (coloration with the C staining solution), it is 15/85 to 50/50% by mass, preferably 20/80 to 40/60% by mass. If the weight average fiber length of the disaggregated pulp is less than 1.0 mm, the tension increases, so that sufficient cushioning properties cannot be obtained, and when compressed, foreign matter cannot be absorbed and the glass surface is damaged. It becomes easy to do. On the other hand, when the weight average fiber length is 1.6 mm or more, because of the long fiber, the entanglement between the pulp fibers is increased, the formation unevenness is generated, and the surface flatness is lowered. The adhesiveness of the slip sheet is lowered, and scratches due to lateral displacement are likely to occur during conveyance.

  Also, kraft pulp has a rigid fiber, and when paper is used without mechanical treatment like conventional glass interleaving paper, the paper structure obtained has many voids and low strength due to low bonding between fibers. In addition, because the paper is only inferior in surface smoothness, the long fibers tend to be considered to have good water dispersibility, but the long fibers are more entangled with each other than the short fibers (and hence the formation is also poor), Water dispersibility due to water is reduced, and when the used metal interleaving paper is water-dispersed, non-dispersion is likely to occur, and it cannot be reused for various purposes as a high-quality pulp raw material. Further, if the blending ratio of NBKP is less than 15% by mass, sufficient cushioning properties cannot be imparted to the interleaving paper for glass, and if it exceeds 50% by mass, binding of pulp fibers occurs. Adhesion with glass is reduced, and damage due to lateral displacement is likely to occur during conveyance.

  By the way, there is a microtopograph that can measure the smoothness under a pressure condition as an index for knowing the adhesion state between the glass and the interleaving paper in a state compressed between the glasses. In the slip sheet for glass, a concavo-convex structure is provided on the surface by a creping treatment from the viewpoint of cushioning properties (see claim 4 of JP-A-2006-44474), or embossing, creping, pinhole processing, etc. It is preferable to provide unevenness (see paragraph 0020 of JP 2007-131965 A) or to make the Beck smoothness 20 seconds or less (see claim 5 of JP 2005-248409 A). Higher smoothness without these irregularities (structures), more preferably higher smoothness in the compressed state results in better adhesion to the glass, resulting in damage to the glass surface due to lateral misalignment. It becomes difficult to do. In this embodiment, the cushioning property of the slip sheet is supplemented by adjusting the basis weight, the weight average fiber length and type of the disaggregated pulp, the average Runkel ratio described later, and the like.

Here, if the microtopograph on one side, preferably both sides of the slip sheet, exceeds 7.0 μm under a 23 kgf / cm ² condition that is assumed to be a pressure applied during conveyance, the boundary between the glass and the slip sheet even under compression conditions. In this case, a lateral shift occurs, and glass damage due to protruding foreign matters such as glass powder existing on the glass surface is likely to occur. Therefore, the thickness is preferably 7.0 μm or less, preferably 2.0 to 7.0 μm. The method of adjusting the microtopograph is not particularly limited, but may be based on a method of appropriately adjusting the type of pulp raw material, the weight average fiber length of the disaggregated pulp, the beating degree, the pressing method, the Runkel ratio, the wet paper drying method, and the like. it can.

  On the other hand, the interleaving paper for glass of this embodiment has a water decomposability (easiness of unraveling) according to JIS P 4501 of 180 seconds or less, preferably 120 to 180 seconds, and when the water decomposability exceeds 180 seconds. In addition, the disaggregation property in the pulper facility is reduced and the volume reduction effect is lowered, and undisaggregation (a state in which the pulp fibers are not completely unraveled) is likely to occur, so that reusability as a pulp raw material is lowered. This method of adjusting water disintegration is performed by beating or classifying so as to have a predetermined weight average fiber length when disaggregated in accordance with JIS P 8220, as well as types of pulp raw materials, types of added chemicals and additions. The amount, pressing method, basis weight and the like can be appropriately adjusted and combined.

The interleaving paper for glass in this embodiment is preferably made in a range of a basis weight of 30 to 60 g / m ² . More preferably, it is 35-50 g / m < ² >. When the basis weight is less than 30 g / m ² , sufficient cushioning properties cannot be obtained. On the other hand, when the basis weight exceeds 60 g / m ² , not only the surface flatness is lowered and it becomes difficult to obtain adhesion with glass, but also the disaggregation property is lowered.

  However, as a factor contributing to cushioning properties, there is a physical structure of the pulp fiber itself in addition to the basis weight and tension of the slip sheet itself as described above. The pulp fiber has a lumen (lumen), which collapses itself and leads to a cushion function as a whole paper. Therefore, the ratio between the lumen and the thickness of the outer ring (cell wall) is important for cushioning. . Therefore, in this embodiment, the cushioning property is optimized by adjusting the average Runkel ratio of the disaggregated pulp of the glass interleaving paper disaggregated according to JIS P 8220. Here, the Runkel ratio R is a value obtained from the width (diameter) L of the lumen of the fiber and the thickness t of the cell wall, and is represented by R = 2 · t / L. This Runkel ratio means that the lower the value, the thinner the fiber wall with respect to the same diameter, and the fiber is more flexible. If the average Runkel ratio is 0.9 or less, it becomes easy to absorb foreign substances such as glass powder at the boundary with the glass under compression conditions into the paper, and the glass is less likely to be damaged. In order to obtain pulp fibers having an average Runkel ratio of 0.9 or less, it is preferable to use planted trees or thinned wood that have been cut at a relatively young stage as wood used as a raw material for pulp. Further, in order to maintain the original shape of the pulp fiber, which is important as a cushion function, the beating is suppressed as much as possible, and the disintegration pulp freeness of the glass interleaving paper disaggregated according to JIS P 8220 is 500 cc or more, preferably 580 to 680 cc. Is desirable. A preferred average Runkel ratio is 0.60 to 0.90.

On the other hand, when the average Runkel ratio of the disaggregated pulp of the glass interleaving paper disaggregated according to JIS P 8220 is set to 0.9 or less, the papermaking method is performed by dewatering with a circular net or a long net, and a Yankee dryer by it is preferable to employ a kraft paper to form a gloss surface on one surface. By producing kraft paper using a Yankee paper machine, the weight average fiber length of the disaggregated pulp of the glass interleaving paper disaggregated according to JIS P 8220 is 1.0 mm or more and less than 1.6 mm. Even when NBKP and LBKP are blended in a mass ratio (ratio) of 15/85 to 50/50, surface flatness is obtained in which the microtopograph on one side, preferably both sides, is 7.0 μm or less under 23 kgf / cm ² conditions. It has a performance that combines both adhesion to the glass and cushioning properties under compression conditions, and the glass and interleaf do not shift laterally during transport, etc. The foreign matter can be absorbed into the interleaf and the glass surface can be prevented from being damaged.

  Furthermore, in this embodiment, by containing a wetting improver (surfactant) in the pulp raw material, even if a substance in the paper adheres to the glass surface, the adhering substance itself contains the wetting improver. Improves the cleaning performance of the glass with the cleaning liquid without reducing the wettability. The kind of wettability improver is not particularly limited, and examples thereof include polyoxyalkylene fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyethylene nonylphenyl ethers, and the like. Among them, in particular, polyoxyalkylene fatty acid esters are present on the surface or in the interior of the most abundant fat component as an adhering component that is transferred from the glass interleaf to the glass surface, so that the adhering material itself has excellent wettability and emulsification. Since it comes to have a function, it is effective in reducing the stain resistance of glass glass and improving the glass cleanability when glass interleaving paper and glass come into contact with each other. In addition, since the fixing to the pulp fiber is good, it is suitable because it greatly contributes to the improvement of the disaggregation of the pulp fiber. External addition means such as film transfer and spraying can be suitably used as a measure for including a wetting improver (surfactant) in the pulp raw material.

The content of the wetting improver in the metal interleaving paper is preferably 0.01 to 0.5% by mass, and more preferably 0.10 to 0.30% by mass. If the content exceeds 0.5% by mass, the hygroscopicity is increased and creases tend to occur, so that the possibility of damaging the glass surface increases. On the other hand, when the content is less than 0.01% by mass, the characteristic effect is not exhibited on the glass surface. Moreover, since the measure to contain a wetting improver has the effect of increasing the water absorption of the slip sheet itself, it also contributes to the improvement of disaggregation, especially when the rice basis weight is high (preferably 50-60 g / m ² ). It is valid.

  In addition to the wetting improver, sizing agents, dryer release agents, sulfuric acid bands, etc. can be used as chemicals to be incorporated in the metal interleaving paper according to the present invention, but in order to reduce the transfer of substances in the paper, such as resin components, to glass. Furthermore, it is preferable that the amount is as small as possible as long as the dryer peeling is not affected.

Next, examples according to the present invention will be described.
The test piece of disaggregated pulp shown in Table 1, the papermaking format, and physical properties were obtained, and for each test piece, the adhesion to glass, the ability to scratch glass, and the contamination to glass were similarly evaluated. It is shown in Table 1.

  In Table 1, a commercially available metal slip paper (commercial A), metal slip paper (commercial B), and a Yankee dryer are used in the same manner as in the present invention to provide a wrapping paper (hand bag). As an example, the glossy kraft paper (commercially available C) was compared as a conventional product approximate to the present invention. Since commercially available C does not take measures against contamination of glass, the resin component in the paper is large, glass stains are remarkable, and the quality cannot be diverted to glass interleaving paper.

[Basis weight]
It is a value measured according to JIS P 8124.

[Strength]
It is a value measured according to JIS P 8118.

[Microtopograph]
Using a microtopograph tester, both sides of the test piece were measured under a pressure of 23 kgf / cm ² , and a low value was shown.

[Hydrolysis (easy to loosen)]
It is a value measured according to JIS P 4501. Specifically, 300 cc water (water temperature 20 ± 5 ° C.) and a disk-shaped magnet rotor having a diameter of 35 mm and a thickness of 12 mm are placed in a 500 cc beaker. This is placed on a magnet stirrer, and the rotational speed of the magnet rotor is adjusted to 600 ± 10 rotations / minute. A 114 mm square test piece was put into the beaker, and after the test piece was completely disaggregated, the time (seconds) until the rotational speed of the rotor in the beaker recovered to 540 rotations was measured.

[Adhesion with glass]
Using glass and test pieces with a size of 500 mm x 500 mm x 0.7 mm in thickness with a cross line clearly specified on the surface, insert the test piece between 100 glasses and each glass so that the cross lines overlap, and set the glass It was created. The entire circumference of the glass set was covered with a moisture-permeable packaging material to prevent external dust and the like from entering. Assuming the environment, vertical load, and horizontal vibration when transporting glass by truck, a glass set is placed on a vibrator frame installed in a constant temperature and humidity chamber maintained at a temperature of 50 ° C and a humidity of 90%. A weight was placed on the upper surface of the glass set so that a pressure of 23 kgf / cm ² was applied, and in this state, a horizontal vibration was performed for 100 hours at a frequency of 15 Hz. After the vibration test, the amount of lateral deviation of the test piece at the glass center point was measured with a ruler, digitized per test piece, and evaluated according to the following criteria.
5: The amount of lateral deviation between the glass and the test piece is less than 1 mm / sheet 4: The amount of lateral deviation between the glass and the test piece is 1 mm or more and less than 2 mm / sheet 3: The amount of lateral deviation between the glass and the test piece is 2 mm or more and less than 3 mm / Sheet 2: The amount of lateral displacement between the glass and the test piece is 3 mm or more and less than 4 mm / sheet 1: The amount of lateral displacement between the glass and the test piece is 4 mm or more / sheet. Is a level.

[Permeability to glass]
In the adhesion evaluation with the glass, the glass after removing the test piece was washed with pure water using an ultrasonic cleaner, the state of the glass surface was observed with a magnifying microscope, and the following criteria were evaluated.

5: Glass surface scratches 0 / sheet 4: Glass surface scratches 1 / sheet 3: Glass surface scratches 2 / sheet 2: Glass surface scratches 3 or more and less than 5 / sheet 1: If the number of scratches on the glass surface is 5 or more / evaluation 3 to 5, it is an acceptable level as a slip sheet for glass.

[Contamination to glass]
In the evaluation of scratchability on the glass, the contact angle with pure water was measured with a contact angle measuring device on the glass surface after ultrasonic cleaning. This measured value was compared with the contact angle of the glass surface before contacting the test piece, and the rate of change of the contact angle of the glass surface was evaluated according to the following criteria.

5: Change rate of contact angle is less than 10% / sheet 4: Change rate of contact angle is 10% or more and less than 20% / sheet 3: Change rate of contact angle is 20% or more and less than 30% / sheet 2: Contact angle Change rate is 30% or more and less than 50% / sheet 1: If the change rate of contact angle is 50% or more / sheet Evaluation 3-5, it is an acceptable level as a slip sheet for glass.

  INDUSTRIAL APPLICABILITY The present invention is a slip sheet that is inserted and used between glasses that require a high degree of surface property, and preferably is inserted and used between glass substrates used in flat panel displays such as liquid crystal televisions and plasma televisions. It can be applied as a glass slip sheet.

Claims (4)

A slip paper for glass mainly composed of pulp raw material,
Under pressure conditions where the weight average fiber length of the disaggregated pulp of the glass interleaving paper disaggregated according to JIS P 8220 is 1.0 mm or more and less than 1.6 mm, and the single-sided or double-sided microtopograph is 23 kgf / cm ² . 7.0 μm or less and water disintegration (easiness to loosen) in accordance with JIS P 4501 is 180 seconds or less.
A slip sheet for glass. The pulp raw material is mainly composed of NBKP and LBKP, and the blended mass ratio (NBKP / LBKP) of the disintegrated pulp of the glass interleaving paper disaggregated according to JIS P 8220 is 15/85 to 50/50,
And basis weight is 30-60 g / m < ² >,
The slip sheet for glass according to claim 1. Kraft paper with a glossy surface on at least one side,
The average Runkel ratio of the disaggregated pulp of the glass interleaving paper disaggregated according to JIS P 8220 is 0.9 or less,
The interleaving paper for glass according to claim 1 or claim 2. The pulp raw material contains a wetting improver,
The interleaving paper for glass according to any one of claims 1 to 3.