Inserting paper for glass plate, manufacturing method of inserting paper for glass plate, and aggregate deposition reduction method

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 distribution process and manufacturing process for stacking and storing and transporting a plurality of glass substrates for flat panel displays such as liquid crystal displays, organic electroluminescence 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 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 disconnection, resulting in product defects. For this reason, the glass substrate surface is required to have a high degree of clarity.

[0003] In recent years, glass substrates are often stacked for transportation in order to improve transportation efficiency as glass substrates become larger and mass-produced. When glass substrates are stacked, the contact pressure between the glass plate interleaf (hereinafter also referred to as "interleaf") and the glass substrate increases, increasing the probability that foreign matter in the interleaf will adhere to (contaminate) the glass substrate. On the other hand, as flat panel displays become more highly precise, the glass substrate surface is required to have a higher degree of clarity. Due to these circumstances, the quality requirements for interleaf paper are becoming more stringent.

[0004] In the process of manufacturing raw pulp and the process of making interleaf paper from raw pulp, foreign matter in the raw material may be mixed into the interleaf paper. In addition, various chemical substances are added, and these additives may have an effect and cause contamination. It is desirable to prevent such foreign matter and contaminants from adhering to the surface of the glass substrate as much as possible during storage or transportation.

[0005] Such foreign matter and contaminants include natural resins and gum substances liberated from wood, pulp and paper, organic water-insoluble substances derived from additives, etc. Specifically, there are 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 medium mainly consisting of water before shipping or before the mounting process of electronic components, etc. This process washes away almost all foreign matter such as paper powder adhering to the glass substrate surface, but there is a high possibility that sticky resins (pitch), foreign matter, and substances with a high affinity for glass will 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 reducing the proportion of talc present on the surface and using, instead, surfactants, cationic polymers, aluminum sulfate (aluminum sulfate), etc. as non-talc pitch control agents. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2016-125146 A Summary of the Invention [Problem to be solved by the invention]

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

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

[0012] In order to solve the above problems, the present inventors have analyzed the adhering foreign matter that causes product defects due to poor formation of electronic components, etc. As a result, it was found that the adhering foreign matter has a size of several tens of μm or more and is an aggregate containing a resin component. Further analysis revealed that aluminum ions are dissociated from aluminum sulfate added as a pitch control agent, and anionic substances, etc. are aggregated due to the strong aggregating action of the aluminum ions, and the aggregates become coarse and become adhering foreign matter.

[0013] The present invention was created based on these findings. That is, the present invention has the following configuration.

[0014] (1) A glass plate interleaving 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 1. A glass plate interleaving paper comprising: (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 mass%. (3) The glass plate interleaving paper according to item 1 or 2, characterized in that the total content of papermaking chemicals is 0 mass%. (4) A method for producing interleaf paper for glass plates, the main component of which is cellulose pulp, the pulp slurry used in the papermaking process being 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 an interleaving paper for glass plates, comprising the steps of: (5) The method for producing interleaving paper for glass plates according to the above item 4, characterized in that 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 interleaving paper for glass plates according to item 4 or 5, characterized in that the talc addition rate in the papermaking process is 0 mass% and the talc content calculated from the ash obtained in accordance with JIS P8251 is 0 mass%. (7) The method for producing interleaving 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 a glass plate, the method being characterized in that a pulp slurry used in a papermaking process is softwood bleached kraft pulp having 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 item 8 above, characterized in that the generation of aggregates of talc and resin (pitch) is completely eliminated. Effect of the Invention

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

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

[0017] The glass plate interleaving paper of the present embodiment is mainly composed of cellulose pulp, has an aluminum content of less than 0.2% by mass, and has a basis weight of 10 to 100 g / m 2 It is.

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

[0019] 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 inhibits adhesion of pulp residue to papermaking equipment. Therefore, aluminum sulfate is often added to stabilize the operability of slip-making.

[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 the like to the pulp fibers and are incorporated into the paper. As a result, the occurrence of problems caused by resins and the like is suppressed.

[0021] However, when aluminum sulfate is added in an amount exceeding a certain level, the resin (pitch) and other materials aggregate to form coarse aggregates, which become so-called incorporation foreign matter. Such coarse aggregates may cause defects in products such as electronic components.

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

[0023] Furthermore, when talc is present, the talc adsorbing the resin (pitch) may aggregate, and the aggregate may become a foreign object when the talc is incorporated. Therefore, the upper limit of the talc content was also examined. As a result, it was 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 mainly composed of cellulose pulp. As the cellulose pulp, one or more of various cellulose pulps can be used in combination. Examples of the 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 paper mulberry, mitsumata, hemp, kenaf, and the like. In the case of wood pulp, it may be softwood pulp or hardwood pulp, or a mixture of these. Furthermore, as the wood pulp, kraft pulp (KP) with a low content of adhesive natural resin derived from wood is preferable. Here, containing cellulose pulp as a 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 interleaf paper.

[0026] The degree of beating of the cellulose pulp is preferably 200 to 700 mlcsf. Here, the degree of beating refers to the Canadian standard freeness according to JIS P8121. By setting the degree of beating in the range of 200 to 700 mlcsf, it is possible to obtain a paper having the mechanical strength and processability required for an interleaf paper. If the degree of beating is less than 200 mlcsf, the density of the interleaf paper for glass plates becomes high, the cushioning property becomes low, and the glass surface becomes easily scratched. If the degree of beating is more than 700 mlcsf, the paper strength becomes weak and there is a risk of breakage during the distribution process or the manufacturing process. The degree of beating is more preferably 350 to 600 mlcsf. In order to adjust the degree of beating to 200 to 700 mlcsf, a known method can be used for beating the pulp.

[0027] (Papermaking chemicals) Regarding the papermaking chemicals used in making the glass plate interleaf paper, various known chemicals can be used within the range that does 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 yield improvers, water resistance agents such as polyamide polyamine epichlorohydrin, softeners, antistatic agents, defoamers, slime control agents, fillers, dyes, etc. Since all of these papermaking chemicals have the potential to contaminate glass plates, it is preferable to limit the total amount to 0.1 mass% or less, even if they are added.

[0028] (Method of manufacturing interleaf paper) The method for producing the glass plate interleaving paper is not particularly limited, and the paper can be produced by using various papermaking machines and selecting appropriate papermaking conditions. Specific examples of the papermaking machine include a Fourdrinier former, a twin-wire former, a cylinder former, and an inclined former. The layer structure of the glass plate interleaving paper may be a single layer or a multilayer.

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

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

[0031] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. The numerical values ​​showing the composition are based on the mass of the solid content or active ingredient. Furthermore, 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 Corporation, PW2404) from a calibration curve that was prepared in advance using slip papers containing a predetermined amount of aluminum.

[0033] <Talc content in slip paper> The glass interleaving paper was incinerated according to JIS P8251. The talc content (mass%) in the obtained ash was determined using a fluorescent X-ray diffraction device (Rigaku Corporation, RINT-UltimaIII) 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: Mass of ash (g) c: Talc content in ash (mass%)

[0034] <Glass plate contamination> (Glass surface contamination test) A 310mm×310mm glass plate interleaf was placed on a 300mm×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 300mm×300mm glass plate for flat panel displays was the same, and the 310mm×310mm glass plate interleaf was changed to a new one for each pressing, and the pressing operation was repeated 100 times to obtain a glass plate for flat panel displays after the test.

[0035] (Evaluation of contamination of glass plate surface) After the above test, the surface of the glass plate for flat panel displays was washed with water, and then a spotlight was applied to the surface of the glass plate to count the amount of stains on the surface of the glass plate visually and under a microscope. The evaluation of the glass plate staining property was performed as follows. ◎: 0 stains ○: 1 stain ×: 2 or more stains

[0036] <Scratch resistance> (Glass 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 2,000 times to obtain a glass plate for flat panel displays after the test.

[0037] (Evaluation of scratch resistance of glass plate surface) After the above test, the surface of the glass plate for flat panel displays was cleaned by brushing, and then a spotlight was applied to the surface of the glass plate, and the number of scratches on the surface of the glass plate was 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 papermaking machine without adding aluminum sulfate or other papermaking chemicals, and the paper was dried to obtain a basis weight of 50 g / m. 2 Thus, a glass plate interleaving paper of 100 g was obtained.

[0039] [Example 2] Except for using a pulp slurry in which 1 mass% of aluminum sulfate 16-hydrate was added to the bone dry pulp mass, an interleaving paper for glass plates was obtained in the same manner as in Example 1. 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 mass%, an interleaving paper for glass plates was obtained in the same manner as in Example 1. The talc content of the obtained interleaving paper for glass plates was 0.05 mass%.

[0041] [Comparative Example 1] Except for adding 4 mass% of aluminum sulfate 16-hydrate, 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 mass%, an interleaving paper for glass plates was obtained in the same manner as in Example 1. The talc content of the obtained interleaving paper for glass plates was 0.25 mass%.

[0043] [Comparative Example 3] An interleaving 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 with 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. A glass plate interleaving paper mainly composed of cellulose pulp, It 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 1. A glass plate interleaving paper comprising:

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

3. 3. The glass plate interleaving paper according to claim 1, wherein the total content of papermaking chemicals is 0% by mass.

4. A method for producing glass plate interleaving paper containing cellulose pulp as a main component, comprising the steps of: 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 A method for producing an interleaving paper for glass plates, comprising the steps of:

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

6. The talc addition rate in the papermaking process is 0% by mass, 6. The method for producing an interleaving paper for glass plates according to claim 4, wherein the talc content determined from the ash obtained in accordance with JIS P8251 is 0 mass%.

7. The method for producing an interleaving paper for glass plates according to any one of claims 4 to 6, characterized in that the total content of papermaking chemicals is 0 mass%.

8. A method for reducing adhesion of aggregates of a glass plate interleaving paper containing cellulose as a main component to a glass plate, comprising: A method for reducing agglomerate adhesion, characterized in that the pulp slurry used in the papermaking process is softwood bleached kraft pulp having a talc content of 0% by mass, and the talc addition rate in the papermaking process is 0% by mass.

9. 9. The method for reducing agglomerate adhesion according to claim 8, characterized in that the generation of agglomerates of talc and resin (pitch) is completely eliminated.

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