Interleaving paper for glass plates, method for manufacturing interleaving paper for glass plates, and method for reducing adhesion of aggregates

Abstract

To provide an inserting paper for a glass plate with reduced deposition of a resin component-based aggregate on a glass plate, a manufacturing method of an inserting paper for a glass plate, and an aggregate deposition reduction method.SOLUTION: An inserting paper for a glass plate includes a cellulose pulp as the main component, wherein the inserting paper for a glass plate is characterized by including a coniferous tree bleached kraft pulp with a talc percentage content of 0 mass% and having a basis weight of 10-100 g / m2. A manufacturing method of an inserting paper for a glass plate containing a cellulose pulp as the main component is a manufacturing method of an inserting paper for a glass plate characterized by that a pulp slurry used in a papermaking process is a coniferous tree bleached kraft pulp with a talc percentage content of 0 mass% and a basis weight is 10-100 g / m2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an interleaf paper to be inserted between glass plates and a method for manufacturing the same, and more particularly to an interleaf paper for glass plates used in the manufacturing process and distribution process for stacking and storing multiple glass substrates for flat panel displays such as liquid crystal displays, organic electroluminescent displays, and plasma displays, and a method for manufacturing the same. [Background technology]

[0002] In recent years, the diversification of glass applications has led to stricter quality requirements for glass plate interleaving paper. For example, in the case of glass substrates used in flat panel displays such as liquid crystal displays, fine electronic components are formed on the glass substrate surface, and even slight scratches or contamination on the surface can cause defects such as broken wires, resulting in product defects. Therefore, the glass substrate surface must have a high level of clarity.

[0003] In recent years, with the increasing size and mass production of glass substrates, glass substrates are often stacked for transportation to improve transportation efficiency. When glass substrates are stacked, the contact pressure between the glass plate interleaf (hereinafter referred to as "interleaf" where appropriate) and the glass substrate increases, increasing the likelihood that foreign matter in the interleaf will adhere to (contaminate) the glass substrate. On the other hand, as flat panel displays become increasingly high-definition, higher levels of clarity are required for the glass substrate surface. Due to these circumstances, the quality standards required for interleaf paper are becoming more stringent.

[0004] During the process of manufacturing raw pulp and the process of making interleaf paper from raw pulp, foreign matter from the raw material may be mixed into the interleaf paper. Furthermore, various chemical substances are added to the pulp, and these additives may cause contamination. It is desirable to minimize the adhesion of such foreign matter and contaminants to the glass substrate surface during storage or transportation.

[0005] These foreign matter and contaminants include natural resins and gums liberated from wood, pulp, and paper, as well as organic, water-insoluble substances derived from additives, etc. Specifically, these include sticky natural resins (pitch) derived from wood, synthetic resins in additives, and resins such as organic polysiloxane compounds, typified by polydimethylsiloxane.

[0006] Glass plates, especially glass substrates used for flat panel displays, undergo a process of cleaning the glass surface using a water-based medium before shipping or before mounting electronic components, etc. This process washes away most of the paper dust and other foreign matter adhering to the glass substrate surface, but sticky resins (pitch), foreign matter, and substances with a high affinity for glass are likely to remain on the glass surface even after cleaning.

[0007] In the pulp manufacturing process and papermaking process, pitch control agents are sometimes used to reduce the adverse effects of resin (pitch). Pitch control agents are substances that prevent resin (pitch) from adhering during the manufacturing process and papermaking process. Specific examples of pitch control agents include talc, aluminum sulfate (aluminum sulfate), surfactants, and cationic polymers.

[0008] For example, Patent Document 1 discloses that the proportion of talc present on the surface is reduced and instead, surfactants, cationic polymers, aluminum sulfate (aluminum sulfate), etc. are used as non-talc pitch control agents. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-125146 Summary of the Invention [Problem to be solved by the invention]

[0010] However, the method of using a pitch control agent described in Patent Document 1 may produce aggregates of resin (pitch) and pitch control agent, and therefore is not necessarily sufficient for use as an interleaving paper for glass substrates, which require extremely high clarity.

[0011] The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an interleaf paper for glass plates that reduces adhesion of agglomerates mainly composed of resin to glass plates, a method for manufacturing the interleaf paper for glass plates, and a method for reducing adhesion of agglomerates. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, the present inventors conducted an analysis of the foreign matter that caused product defects due to poor formation of electronic components, etc. As a result, it was found that the foreign matter was agglomerates containing resin, with a size of several tens of micrometers or more. Further analysis revealed that aluminum ions were dissociated from aluminum sulfate added as a pitch control agent, and the strong aggregating action of the aluminum ions caused anionic substances to aggregate, which then coarsened and became the foreign matter.

[0013] The present invention was developed based on these findings, and has the following features.

[0014] (1) A glass sheet interleaf paper mainly composed of cellulose pulp, containing softwood bleached kraft pulp with a talc content of 0% by mass, and having a basis weight of 10 to 100 g / m 2 An interleaving paper for glass plates, characterized in that: (2) The glass plate interleaving paper according to the above item 1, characterized in that the talc content determined from ash obtained in accordance with JIS P8251 is 0% by mass. (3) The glass plate interleaving paper according to item 1 or 2, characterized in that the total content of papermaking chemicals is 0% by mass. (4) A method for producing glass plate interleaf paper mainly composed of cellulose pulp, in which the pulp slurry used in the papermaking process is softwood bleached kraft pulp with a talc content of 0% by mass and a basis weight of 10 to 100 g / m 2 A method for producing interleaf paper for glass plates, characterized by: (5) The method for producing interleaf paper for glass plates according to (4) above, wherein the softwood bleached kraft pulp is obtained by setting the talc addition rate to 0 mass % in the pulp production process. (6) The method for producing interleaf paper for glass plates according to item 4 or 5, characterized in that the talc addition rate in the papermaking process is 0% by mass, and the talc content determined from ash obtained in accordance with JIS P8251 is 0% by mass. (7) The method for producing interleaf paper for glass plates according to any one of (4) to (6), characterized in that the total content of papermaking chemicals is 0 mass %. (8) A method for reducing adhesion of agglomerates of glass plate interleaf paper containing cellulose as a main component to glass plates, the method being characterized in that the pulp slurry used in the papermaking process is softwood bleached kraft pulp with a talc content of 0% by mass, and the talc addition rate in the papermaking process is 0% by mass. (9) The method for reducing adhesion of aggregates according to the above item 8, characterized in that the generation of aggregates of talc and resin (pitch) is completely eliminated. [Effects of the Invention]

[0015] According to the interleaf paper for glass plates of the present invention, adhesion of aggregates mainly composed of resin components to glass plates can be reduced. According to the method for producing an interleaf paper for glass plates of the present invention, it is possible to produce an interleaf paper for glass plates that can reduce adhesion of aggregates mainly composed of resin components to glass plates. According to the method for reducing adhesion of aggregates of the present invention, adhesion of aggregates mainly composed of resin components to a glass plate can be reduced. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below. The embodiments shown below are merely examples, and the present invention should not be construed as being limited to these embodiments.

[0017] The glass plate interleaf paper of this embodiment contains cellulose pulp as a main component, has an aluminum content of less than 0.2% by mass, and has a basis weight of 10 to 100 g / m 2 is.

[0018] (aluminum) The present inventors have conducted an analysis of the foreign matter that causes defects in electronic components and other products. As a result, it was found that the foreign matter is an aggregate of resin components, and has a size of several tens of micrometers or more. Furthermore, it was found that the foreign matter contains aluminum.

[0019] The aluminum is mainly derived from aluminum sulfate, which is used as a papermaking chemical. Aluminum sulfate not only functions as a pitch control agent, but also fixes sizing agents, improves drainage, and prevents pulp residue from adhering to papermaking equipment. Therefore, aluminum sulfate is often added to stabilize the operability of interleaf paper production.

[0020] The mechanism by which aluminum sulfate functions as a pitch control agent is as follows: The aluminum ions dissociated from aluminum sulfate are cationic, so they bind anionic resins and other substances to pulp fibers and are incorporated into the paper. As a result, the occurrence of adverse effects caused by resins and other substances is suppressed.

[0021] However, when aluminum sulfate is added in excess of a certain amount, the resin (pitch) and other components aggregate to form coarse aggregates, which become so-called inclusion particles. These coarse aggregates may cause defects in electronic components and other products.

[0022] Based on the above results, the present inventors have found that in order to prevent resin-based aggregates from adhering to the glass plate interleaf, it is necessary to set the aluminum content to less than 0.2% by mass, and it is preferable that the aluminum content be less than 0.01% by mass.

[0023] Furthermore, when talc is present, the talc adsorbing the resin (pitch) may aggregate, and these aggregates may become inclusions. Therefore, we also investigated the upper limit of the talc content. As a result, we found that the talc content is preferably less than 0.1% by mass. The talc content is more preferably less than 0.01% by mass.

[0024] Paper that uses a certain amount or more of aluminum sulfate as a papermaking chemical becomes so-called acidic paper when the hot water extraction pH measured in accordance with JIS P8133 is about 4 to 5.5.

[0025] (cellulose pulp) The glass plate interleaf paper of this embodiment is primarily composed of cellulose pulp. The cellulose pulp may be one or a mixture of two or more different types of cellulose pulp. Examples of cellulose pulp include chemical pulps such as kraft pulp (KP), sulfite pulp (SP), and soda pulp (AP); semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-ground wood pulp (CGP); mechanical pulps such as groundwood pulp (GP), thermomechanical pulp (TMP, BCTMP), and refiner ground wood pulp (RGP); and non-wood fiber pulps made from materials such as paper mulberry, mitsumata, hemp, and kenaf. Wood pulp may be softwood pulp, hardwood pulp, or a mixture of these. Furthermore, kraft pulp (KP), which has a low content of natural adhesive resins derived from wood, is preferred. Here, "containing cellulose pulp as the main component" means that the cellulose pulp accounts for more than 50% by mass, preferably 70% by mass or more, and more preferably 90% by mass or more, of the mass of the slip sheet.

[0026] The beating degree of the cellulose pulp is preferably 200 to 700 mlcsf. Here, the beating degree refers to the Canadian standard freeness according to JIS P8121. By setting the beating degree in the range of 200 to 700 mlcsf, the interleaf paper can have the mechanical strength and processability required. If the beating degree is less than 200 mlcsf, the density of the interleaf paper for glass plates increases, the cushioning properties decrease, and the glass surface becomes more susceptible to scratches. If the beating degree is more than 700 mlcsf, the paper strength decreases and there is a risk of breakage during transportation and distribution or during the manufacturing process. The beating degree is more preferably 350 to 600 mlcsf. Known methods can be used to beat the pulp to adjust the beating degree to 200 to 700 mlcsf.

[0027] (Papermaking chemicals) Various known papermaking chemicals can be used during the production of glass plate interleaf paper, provided they do not contaminate or damage the glass surface. Examples of papermaking chemicals include sizing agents such as rosin, styrene-maleic acid, alkenyl succinic anhydride, and alkyl ketene dimer, paper strength agents such as polyacrylamide, drainage retention aids, water-resistant agents such as polyamide polyamine epichlorohydrin, softeners, antistatic agents, antifoaming agents, slime control agents, fillers, and dyes. Because these papermaking chemicals all have the potential to contaminate glass plates, it is preferable to limit their total amount to 0.1% by mass or less, even if they are added.

[0028] (Interleaf Paper Manufacturing Method) There are no particular limitations on the method for producing the glass plate interleaf paper, and it can be produced using various papermaking machines by selecting appropriate papermaking conditions. Specific examples of papermaking machines include Fourdrinier formers, twin-wire formers, cylinder formers, and inclined formers. The layer structure of the glass plate interleaf paper may be single-layered or multi-layered.

[0029] (Characteristics of glass plate interleaf paper) The smaller the basis weight of the glass plate interleaf paper, the less weight it will have during transportation, which is preferable, but if it is too small, it will not be able to provide sufficient cushioning to the glass plate. On the other hand, a somewhat larger basis weight of the interleaf paper is preferable in terms of cushioning, but if it is too large, the weight will increase during transportation, which is not preferable. Considering the balance between cushioning properties and ease of transportation, the basis weight of the interleaf paper should be 10 to 100 g / m 2 The basis weight of the slip sheet is preferably 35 to 80 g / m 2 is.

[0030] The thickness of the glass plate interleaf paper is preferably 25 to 250 μm from the viewpoint of cushioning properties and workability. The density of the glass plate interleaf paper is preferably 0.4 to 1.2 g / cm. 3 It is preferable that: [Example]

[0031] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The numerical values ​​indicating the composition are based on the mass of the solid content or active ingredient. Unless otherwise specified, the paper produced was treated in accordance with JIS P8111 and then subjected to measurement and evaluation tests.

[0032] <Aluminum content in slip paper> The aluminum content (mass %) in the slip paper was determined using a fluorescent X-ray analyzer (Spectris, PW2404) based on a calibration curve prepared in advance using slip paper containing a predetermined amount of aluminum.

[0033] <Talc content in slip paper> The glass interleaving paper was ashed according to JIS P8251. Next, the talc content (mass%) in the resulting ash was determined using a fluorescent X-ray diffractometer (Rigaku Corporation, RINT-Ultima III) with a calibration curve prepared in advance using interleaving paper containing a predetermined amount of talc. The talc content m in the glass interleaving paper was calculated using the following formula (1): m = (b / a) × c × 100 (1) Where m: talc content (mass%) a: Mass of glass interleaving paper (g) b: Ash mass (g) c: Talc content in ash (mass%)

[0034] <Glass plate contamination> (Glass plate surface contamination test) A 310mm x 310mm glass plate interleaf paper was placed on a 300mm x 300mm glass plate for flat panel displays, and a pressing operation was repeatedly performed in which a pressure of 0.7 MPa was applied for 10 seconds. That is, the same 300mm x 300mm glass plate for flat panel displays was used, and the 310mm x 310mm glass plate interleaf paper was changed to a new one each time, and the pressing operation was repeated 100 times to obtain a glass plate for flat panel displays after the test.

[0035] (Evaluation of contamination on glass plate surface) After the above test, the surface of the glass plate for a flat panel display was rinsed with water, and then a spotlight was shone on the surface of the glass plate, and the amount of stains on the surface of the glass plate was counted visually and under a microscope. The evaluation of glass plate staining was performed as follows. ◎: 0 stains ○: 1 stain ×: Two or more stains

[0036] <Scratch resistance> (Glass plate surface scratch test) A 310mm x 310mm glass interleaving paper was placed on a 300mm x 300mm glass plate for flat panel displays and pressed at 0.7 MPa for 10 seconds. The 300mm x 300mm glass plate for flat panel displays was the same, but the 310mm x 310mm glass interleaving paper was changed to a new one after each pressing, and the pressing was repeated 2000 times to obtain a glass plate for flat panel displays after the test.

[0037] (Evaluation of scratch resistance on glass plate surface) After the above test, the surface of the glass plate for a flat panel display was cleaned by brushing, and then a spotlight was shone on the surface of the glass plate, and scratches on the surface of the glass plate were counted visually and under a microscope. ○: 0 to 4 scratches ×: 5 or more scratches

[0038] [Example 1] A pulp slurry (beaten to a degree of 450 mlcsf) containing 100% commercially available bleached softwood kraft pulp (NBKP) with a talc content of 0% by mass was used to make paper on a fourdrinier paper machine without adding aluminum sulfate or other papermaking chemicals, and the paper was dried to a basis weight of 50 g / m. 2 As a result, an interleaf paper for glass plates of 100g was obtained.

[0039] [Example 2] An interleaving paper for glass plates was obtained in the same manner as in Example 1, except that a pulp slurry in which aluminum sulfate hexahydrate was added in an amount of 1 mass% relative to the bone-dry pulp mass was used. The aluminum content of the obtained interleaving paper for glass plates was 0.08 mass%.

[0040] [Example 3] Except for using a commercially available 100% pulp slurry of NBKP (softwood bleached kraft pulp) with a talc content of 0.2% by mass, an interleaf paper for glass plates was obtained in the same manner as in Example 1. The talc content of the obtained interleaf paper for glass plates was 0.05% by mass.

[0041] [Comparative Example 1] Except for adding 4 mass% of aluminum sulfate hexahydrate, an interleaving paper for glass plates was obtained in the same manner as in Example 2. The aluminum content of the obtained interleaving paper for glass plates was 0.31 mass%.

[0042] Comparative Example 2 Except for using a commercially available 100% pulp slurry of NBKP (softwood bleached kraft pulp) with a talc content of 1% by mass, an interleaf paper for glass plates was obtained in the same manner as in Example 1. The talc content of the obtained interleaf paper for glass plates was 0.25% by mass.

[0043] Comparative Example 3 An interleaf paper for glass plates was obtained in the same manner as in Comparative Example 2, except that the beating degree was set to 150 mlcsf.

[0044] [Table 1]

[0045] Table 1 shows the evaluation results of Examples 1 to 3 and Comparative Examples 1 to 3. The glass plate interleaving papers of Examples 1 to 3 were excellent in glass plate contamination resistance. Furthermore, compared to Example 3, which contained talc, Examples 1 and 2, which did not contain talc, were even more excellent in glass plate contamination resistance. On the other hand, the glass plate interleaving papers of Comparative Examples 1 and 2 were poor in glass plate contamination resistance. The glass plate interleaving paper of Comparative Example 3 was poor in glass plate contamination resistance and scratch resistance.

Claims

1. An interleaving paper for glass plates containing cellulose pulp as a main component, Contains softwood bleached kraft pulp with a talc content of 0% by mass, and has a basis weight of 10 to 100 g / m ２ and the total content of papermaking chemicals is 0% by mass.

2. 2. The glass plate interleaving paper according to claim 1, wherein the talc content determined from ash obtained in accordance with JIS P8251 is 0% by mass.

3. A method for producing interleaving paper for glass plates containing cellulose pulp as a main component, comprising: The pulp slurry used in the papermaking process is softwood bleached kraft pulp with a talc content of 0% by mass, Basis weight: 10 to 100 g / m ２ and a total content of papermaking chemicals of 0 mass %.

4. 4. The method for producing interleaf paper for glass plates according to claim 3, wherein the softwood bleached kraft pulp is obtained by setting the talc addition rate to 0 mass % in a pulp production process.

5. The talc addition rate in the papermaking process is 0% by mass, 5. The method for producing an interleaf paper for glass plates according to claim 3, wherein the talc content determined from the ash obtained in accordance with JIS P8251 is 0% by mass.

6. 1. A method for reducing adhesion of agglomerates of glass plate interleaf paper containing cellulose as a main component to a glass plate, the method comprising: A method for reducing aggregate adhesion, characterized in that the pulp slurry used in the papermaking process is softwood bleached kraft pulp with a talc content of 0% by mass, has a basis weight of 10 to 100 g / m 2 , and contains 0% by mass of the total content of papermaking chemicals.

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