Pulp for glass laminating paper, glass laminating paper, and method for producing the same

Abstract

The present invention provides: pulp which is for glass interleaving paper, which can be produced in a pulp production process with suppressed foaming, and in which the occurrence of an aggregate having silicone oil as the main component is reduced; a production method which is for glass interleaving paper, which enables production in a pulp production process with suppressed foaming, and which reduces the occurrence of an aggregate having silicone oil as the main component; and glass interleaving paper which reduces contamination of a glass substrate surface caused by an aggregate having silicone oil as the main component. Provided is a pulp which is for glass interleaving paper and which comprises a hydrophilic modified silicone oil, wherein the content of the silicone oil with respect to pulp is 0.5-2 mg / kg. Also provided is glass interleaving paper in which cellulose pulp is the main component, which comprises a hydrophilic modified silicone oil, and which has a basis weight of 10-100 g / m2, wherein the content of the silicone oil with respect to the glass interleaving paper is 0.01-0.3 mg / kg. Also provided is a production method for the glass interleaving paper.

Description

Technical Field

[0001] The present invention relates to pulp for glass interleaving paper, glass interleaving paper, and a method for manufacturing the same.

Background Art

[0002] With the diversification of uses of glass substrates, the quality requirements for glass interleaving paper have become stricter. For example, in glass substrates used for flat panel displays such as liquid crystal displays, organic electroluminescence displays, touch panels, and plasma displays, since fine electronic components and the like are formed on the surface of the glass substrate, even a slight scratch or contamination on the surface may cause defects such as disconnection and result in product defects. Therefore, a high degree of clarity is required for the surface of the glass substrate. In particular, an extremely high degree of clarity is required for the surface of glass substrates used for liquid crystal displays for TFTs and color filters, and organic electroluminescence displays.

[0003] For the purpose of increasing the transport efficiency of glass substrates, glass substrates are often stacked and transported using glass interleaving paper. When glass substrates are stacked, the contact pressure between the glass interleaving paper and the glass substrates increases due to their weight, so the probability that trace components and foreign substances in the glass interleaving paper cause problems to the glass substrates increases. On the other hand, with the progress of high-definition processing of glass substrates, a higher degree of clarity is required for the surface of the glass substrates. Due to such circumstances, the quality requirement level for glass interleaving paper is becoming increasingly high.

[0004] Foreign substances and contaminants generated in the manufacturing process of raw pulp, and foreign substances and contaminants generated in the process of papermaking glass interleaving paper from raw pulp often mix into the glass interleaving paper. The foreign substances and contaminants mixed into the glass interleaving paper are transferred (contaminated) from the glass interleaving paper to the surface of the glass substrate during storage or transportation, causing problems to the glass substrate.

[0005] Regarding a glass substrate, particularly a glass substrate used for flat panel displays, before shipment or before the mounting process of electronic components and the like, a process of cleaning the surface of the glass substrate using a medium mainly composed of water is carried out. By this process, most of the foreign matters such as paper dust adhering to the surface of the glass substrate are washed away, but some of the foreign matters and contaminants may still adhere to the surface of the glass substrate after cleaning.

[0006] Such foreign matters and contaminants include organic non - water - soluble substances derived from natural resins, gum substances, additives, etc. released from wood, pulp, and paper. Among them, silicone oil contained in the defoaming agent used during pulp production has a strong affinity with glass, and it is difficult to remove even when the glass substrate is cleaned with a brush or the like using a cleaning liquid or water. It generates hydrophobic aggregates on the surface of the glass substrate. As a result, problems such as disconnection occur in the mounting process of electronic components and the like.

[0007] Therefore, for example, in Patent Document 1, it is disclosed that a wood pulp for glass - laminated paper in which the silicone content in wood pulp is 0.5 ppm or less based on the absolutely dry mass of the pulp is used. Further, in Patent Document 2, a wood pulp for glass - laminated paper is disclosed, in which the fluorescence X - ray intensity of silicon on the surface of the hand - made paper prepared by a method conforming to JIS P 8222 using the wood pulp has 50 discontinuous regions of 1 cps or more per 1000 m 2 The following wood pulp for glass - laminated paper is disclosed.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] In Patent Document 1, when the silicone content in the pulp is set to 0.5 ppm or less, it is necessary to lower the addition rate of the antifoaming agent, so that the foaming countermeasures in the pulp manufacturing process may be insufficient. To obtain the pulp described in Patent Document 2, it is necessary to repeat solvent washing in which the pulp is washed with a solvent mixture of toluene and methanol in the washing step and then filtered. Therefore, it is necessary to provide solvent-resistant equipment in a normal pulp production line, which is costly and laborious.

[0010] The present invention has been made in view of the above circumstances. That is, an object of the present invention is to provide a pulp for glass laminated paper that can be manufactured while suppressing foaming in the pulp manufacturing process and reducing the generation of aggregates mainly composed of silicone oil. Another object is to provide a method for manufacturing glass laminated paper that can be manufactured while suppressing foaming in the pulp manufacturing process and reducing the generation of aggregates mainly composed of silicone oil. Still another object is to provide a glass laminated paper with reduced contamination of the glass substrate surface by aggregates mainly composed of silicone oil.

Means for Solving the Problems

[0011] The inventor of the present invention studied an antifoaming agent added to suppress foaming in the pulp manufacturing process. As a result, it was found that by using a specific type of antifoaming agent in a specific amount, both suppression of foaming in the pulp manufacturing process and reduction of contamination of the glass substrate surface by aggregates of silicone oil can be solved simultaneously, leading to the creation of the present invention. That is, the present invention has the following configuration.

[0012] (1) A pulp for glass laminated paper containing a hydrophilic-modified silicone oil, wherein the content of the hydrophilic-modified silicone oil with respect to the pulp is 0.5 to 2 mg / kg as a silicone content.

[0013] (2) The hydrophilic modified silicone oil is contained in a silicone-based defoaming agent, and the silicone-based defoaming agent is an oil-in-water type silicone-based defoaming agent. The pulp for glass laminated paper according to (1) above is characterized in that.

[0014] (3) A method for producing glass laminated paper using a silicone-based defoaming agent containing a hydrophilic modified silicone oil as a defoaming agent in the pulp manufacturing process, wherein the addition rate of the silicone-based defoaming agent to the pulp is 0.5 to 2 mg / kg as the silicone content. A method for producing glass laminated paper, characterized in that.

[0015] (4) The method for producing glass laminated paper according to (3) above, wherein the silicone-based defoaming agent containing the hydrophilic modified silicone oil is an oil-in-water type silicone-based defoaming agent.

[0016] (5) A glass laminated paper mainly composed of cellulose pulp, containing a hydrophilic modified silicone oil, and having a basis weight of 10 to 100 g / m 2 The glass laminated paper is characterized in that the content of the hydrophilic modified silicone oil in the glass laminated paper is 0.01 to 0.3 mg / kg as the silicone content.

[0017] (6) The hydrophilic modified silicone oil is contained in a silicone-based defoaming agent, and the silicone-based defoaming agent is an oil-in-water type silicone-based defoaming agent. The glass laminated paper according to (5) above is characterized in that.

[0018] (7) The glass laminated paper according to (5) or (6) above, characterized in that the content of talc added as a pitch control agent is less than 0.1% by mass.

Advantages of the Invention

[0019] The pulp for glass lamination paper of the present invention can be manufactured by suppressing foaming in the pulp manufacturing process, and can reduce the generation of aggregates mainly composed of silicone oil. Further, the method for manufacturing glass lamination paper of the present invention can be manufactured by suppressing foaming in the pulp manufacturing process, and can reduce the generation of aggregates mainly composed of silicone oil. Further, the glass lamination paper of the present invention can reduce the contamination of the surface of the glass substrate by aggregates mainly composed of silicone oil.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, the present invention will be specifically described. The following embodiments are examples, and the present invention is not construed as being limited to these embodiments.

[0021] The present inventor has advanced the analysis of adhering (contaminating) foreign matters that cause defects in electronic components and the like formed on the surface of the glass substrate. As a result, it has been found that the residual foreign matter adhering to the surface of the glass substrate even after the water washing process is an aggregate containing silicone oil, and may have a size of several μm or more.

[0022] In the pulp manufacturing process, in the pulp washing process and the pulp bleaching process, it is essential to use an antifoaming agent in order to reduce the adverse effects caused by foaming. Silicone oil is widely used as an antifoaming agent in the pulp manufacturing process. Therefore, the present inventor has studied the antifoaming agent used in the pulp manufacturing process.

[0023] Typical defoamers include mineral oil-based defoamers and silicone-based defoamers. The composition of mineral oil-based defoamers consists of mineral oil, hydrophobic silica, silicone oil, extender solvent, emulsifier, water, etc. Silicone-based defoamers include oil-based emulsion types (W / O type: water-in-oil type) and self-emulsifying water-based emulsion types (O / W type: oil-in-water type). The composition of both types consists of silicone oil, extender solvent, emulsifier, water, etc. Thus, the defoamers used in the pulp manufacturing process contain silicone oil, whether they are mineral oil-based or silicone-based.

[0024] Silicone oil is a linear polymer connected by siloxane bonds with dimethylsiloxane as the main monomer unit. A part of methylphenylsiloxane or methylhydroxysiloxane can be contained in the main chain. Also, modified silicone oils are those in which various functional groups are introduced and modified at the ends or side chains (described later).

[0025] Silicone-based defoamers have a higher defoaming effect compared to mineral oil-based defoamers, so the addition amount can be reduced to 1 / 5 to 1 / 10 compared to mineral oil-based defoamers. Therefore, silicone-based defoamers are often used.

[0026] Silicone oil has a high affinity for pulp fibers and is usually adsorbed uniformly on the surface of pulp fibers. In such cases, problems such as disconnection are less likely to occur in the mounting process of electronic components, etc. However, since silicone oil is hydrophobic and insoluble in water, it exists as an oily substance in water. Therefore, silicone oil is likely to aggregate with hydrophobic substances in water to generate coarse aggregates. When the silicone oil aggregates and coarsens to become foreign matter with a size of, for example, several μm or more, problems will occur due to the transfer (contamination) of the aggregates or components mainly composed of a part of the silicone oil in the aggregates to the surface of the glass substrate.

[0027] Natural resins (colloidal pitch) and gum substances liberated in the pulp manufacturing process are water-insoluble hydrophobic substances. Also, talc used as a pitch control agent in the pulp manufacturing process is a hydrophobic substance. The hydrophobic talc adsorbs the same hydrophobic natural resins and gum substances to form aggregates. Similarly, hydrophobic silicone oil adsorbs natural resins, gum substances, and talc to form aggregates.

[0028] Among defoamers, when a mineral oil-based defoamer or an oil-based emulsion type (W / O type: water-in-oil type) silicone-based defoamer is used, there is a great concern that the silicone oil contained in the defoamer combines with organic water-insoluble substances derived from natural resins and gum substances liberated in the pulp manufacturing process and talc used as a pitch control agent in the pulp manufacturing process to form coarse aggregates.

[0029] As described above, silicone-based defoamers include an oil-based emulsion type (water-in-oil type: W / O type) and a self-emulsifying water-based emulsion type (O / W type: oil-in-water type). Among these, the oil-in-water type silicone-based defoamer has high water dispersibility.

[0030] In recent years, various modified silicone oils have been developed to functionalize silicone oil. Modified silicone oil has a structure in which a part of the methyl groups of polydimethylsiloxane is replaced with an organic functional group. Examples of modified silicone oils include amino modification, epoxy modification, carboxyl modification, polyether modification, etc.

[0031] As an organic functional group, for example, polyether-modified silicone oil with a polyether group introduced is added with polyethylene glycol, polypropylene glycol, polyethylene glycol - polypropylene glycol copolymer, etc. By changing the ratio of the organic functional group in the polyether-modified silicone oil and the ethylene oxide (EO) / propylene oxide (PO) ratio, the solubility in water or alcohol can be changed, and a hydrophilic (water-soluble) modified silicone oil can be obtained.

[0032] Therefore, the present inventor focused on a self-emulsifying water-based emulsion type (O / W type: oil-in-water type) silicone-based defoamer containing a hydrophilic (water-soluble) modified silicone oil. Examples of the hydrophilic (water-soluble) modified silicone oil include the product named "SN Deformer 503K" by Sannopco.

[0033] The present inventor found that a self-emulsifying water-based emulsion type (O / W type: oil-in-water type) silicone-based defoamer containing a hydrophilic (water-soluble) modified silicone oil has poor affinity with hydrophobic natural resins, gum substances, and talc, and it is difficult to generate aggregates. As a result, it was found that the generation of coarse aggregates that cause problems such as disconnection in the mounting process of electronic components and the like is greatly reduced.

[0034] The defoamer used in the pulp manufacturing process is an auxiliary agent required in the cooking process and bleaching process of wood chips, but it is usually unnecessary in the refined pulp after washing. Therefore, it is preferable that the defoamer does not remain in the refined pulp. Furthermore, it is preferable that the defoamer does not remain in the papermaking process of glassine paper using the pulp.

[0035] Therefore, the inventor used a silicone-based defoaming agent containing a hydrophilic (water-soluble) modified silicone oil in the pulp manufacturing process. As a result, due to the shear force during washing in the pulp manufacturing process and the subsequent papermaking process, the defoaming agent was easily refined in water and was easy to wash away. Thus, it was found that the residual amount in the glass paper was significantly reduced compared to the addition amount to the pulp during pulp manufacturing.

[0036] Furthermore, in a glass substrate, particularly a glass substrate used for flat panel displays, there is a step of cleaning the surface of the glass substrate using a water-based medium before shipment or before the mounting process of electronic components or the like. The hydrophilic (water-soluble) modified silicone oil that remains slightly in the glass paper and is transferred to the glass substrate is also washed away and removed in this cleaning step.

[0037] The inventor actually used an oil-in-water type silicone-based defoaming agent containing a hydrophilic (water-soluble) modified silicone oil (hereinafter simply referred to as "silicone-based defoaming agent containing a hydrophilic (water-soluble) modified silicone oil") in the pulp manufacturing process, and varied the addition amount to create glass paper. Furthermore, the inventor conducted a transport test of the glass substrate using the glass paper and confirmed the disconnection status of the wiring formed on the glass substrate.

[0038] As a result, in the pulp manufacturing process, when a silicone-based defoaming agent containing a hydrophilic (water-soluble) modified silicone oil was added to the pulp and the content of the hydrophilic (water-soluble) modified silicone oil in the finished pulp after pulp manufacturing was 0.5 to 2 mg / kg as the silicone content, it was possible to suppress foaming during pulp manufacturing, reduce the generation of aggregates mainly composed of silicone oil, and suppress the occurrence of disconnection. The addition rate of the silicone-based defoaming agent containing a hydrophilic (water-soluble) modified silicone oil to the pulp is more preferably 0.6 to 1.5 mg / kg as the silicone content.

[0039] In addition, the silicone content is a value obtained by measuring the 1 H-NMR spectrum of the extract obtained from pulp or glassine paper by Soxhlet extraction using hexane and determining it as the mass content of dimethylsiloxane units (described later). 1 H-NMR spectrum was measured and determined as the mass content of dimethylsiloxane units (described later).

[0040] Similarly, as for the pulp for glassine paper, when the content of hydrophilic (water-soluble) modified silicone oil with respect to the pulp is 0.5 to 2 mg / kg as the silicone content, the generation of aggregates mainly composed of silicone oil can be reduced, and the occurrence of wire breakage can be suppressed.

[0041] Furthermore, a silicone-based antifoaming agent containing a hydrophilic (water-soluble) modified silicone oil was added to the pulp for glassine paper, and when the content of the hydrophilic (water-soluble) modified silicone oil with respect to the finished pulp after pulp production was 0.5 to 2 mg / kg as the silicone content, the content of the hydrophilic (water-soluble) modified silicone oil in the obtained glassine paper was measured. As a result, for a glassine paper in which the content of the hydrophilic (water-soluble) modified silicone oil with respect to the pulp for glassine paper is 0.01 to 0.3 mg / kg as the silicone content, the generation of aggregates mainly composed of silicone oil can be reduced, and the occurrence of wire breakage can be suppressed. A glassine paper having a silicone content of 0.01 to 0.3 mg / kg is preferred.

[0042] Furthermore, the present inventor also studied the upper limit of the content of talc added as a pitch control agent during the production of pulp or glassine paper. As a result, it was found that in order to reduce the generation of aggregates of silicone oil and suppress the occurrence of wire breakage, the content of talc in pulp or glassine paper is preferably less than 0.1% by mass. More preferably, the content of talc in pulp or glassine paper is less than 0.01% by mass.

[0043] (Pulp) The glass interleaving paper is mainly composed of cellulose pulp with a low content of sticky natural resin (pitch) derived from wood. As the cellulose pulp, chemical pulp is preferred, and kraft pulp (KP) is particularly preferred. Here, the phrase "mainly composed of cellulose pulp" means that the content of cellulose pulp exceeds 50% by mass based on the mass of the glass interleaving paper. The cellulose pulp content is preferably 70% by mass or more, and more preferably 90% by mass or more, based on the mass of the glass interleaving paper. Examples of chemical pulps other than kraft pulp include sulfite pulp (SP), soda pulp (AP), and the like.

[0044] The beating degree of the pulp is preferably 200 - 700 mlcsf. Here, the beating degree refers to the Canadian standard freeness according to JIS P8121. By setting the beating degree of the pulp in the range of 200 - 700 mlcsf, it is possible to obtain a product having the mechanical strength and processability required for glass interleaving paper. When the beating degree of the pulp is less than 200 mlcsf, the density of the glass interleaving paper tends to be high and the cushioning property tends to be low, so there is a risk that the surface of the glass substrate will be easily scratched. On the other hand, when the beating degree of the pulp is higher than 700 mlcsf, the paper strength becomes weak, so there is a risk of breakage during the distribution process or the manufacturing process. The beating degree of the pulp is more preferably 350 - 600 mlcsf. As for the method of beating the pulp, known methods can be used.

[0045] Regarding the papermaking chemicals used during the papermaking of the glass interleaving paper, various known chemicals can be used as long as they do not contaminate the glass surface. Examples of papermaking chemicals include paper strength enhancers such as polyacrylamide, water resistance agents such as polyamide polyamine epichlorohydrin, softeners, antistatic agents, defoamers, slime control agents, fillers, dyes, and the like. Since all of these papermaking chemicals have the potential to contaminate the glass substrate, even when adding them, the total amount is preferably 0.1% by mass or less.

[0046] (Method for manufacturing glass interleaving paper) The manufacturing method of the glass interleaving paper is not particularly limited, and it can be manufactured by selecting appropriate papermaking conditions using various papermaking machines. Specifically, examples of the papermaking machines include a Fourdrinier former, a twin-wire former, a cylinder former, and an inclined former. The layer structure of the glass interleaving paper may be single-layer or multi-layer.

[0047] (Glass interleaving paper) The basis weight of the glass interleaving paper is preferably small because the mass during transportation is reduced, but if it is too small, a sufficient buffering function cannot be imparted to the glass substrate. On the other hand, a somewhat larger basis weight of the glass interleaving paper is preferable in terms of the buffering function, but if it is too large, the mass during transportation becomes large, which is not preferable. Considering the balance between the buffering function and the mass, and the application, the basis weight of the glass interleaving paper is 10~100 g / m 2 It is set as follows. A more preferable basis weight of the glass interleaving paper is 30~80 g / m 2 It is.

[0048] From the viewpoints of cushioning property and workability, the thickness of the glass interleaving paper is preferably 25~250 μm. Also, the density of the glass interleaving paper is preferably 0.4~1.2 g / cm 3 It is.

[0049] The glass interleaving paper of this embodiment is suitably used for protecting glass substrates when a plurality of glass substrates for flat panel displays such as liquid crystal displays, organic electroluminescence displays, touch panels, and plasma displays are stacked and stored or transported. Among them, it is suitably used for liquid crystal displays (for TFTs, for color filters) and organic electroluminescence displays that require extremely high clarity.

Example

[0050] Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. The numerical values indicating the formulation are values (mass %) based on the mass of the solid content or the active ingredient. In addition, unless otherwise specified, the paper after papermaking was processed according to JIS P8111 and then subjected to measurement and evaluation tests.

[0051] <Silicone content in pulp or glass laminated paper> The pulp was cut into pieces of about 1 cm square. Also, the glass laminated paper was cut into pieces of about 1 cm square. Soxhlet extraction was carried out for about 3 hours and 30 minutes using hexane as a solvent to extract components from the pulp or glass laminated paper. The obtained extract was concentrated to dryness using a rotary evaporator and redissolved in 1 mL of deuterated chloroform to obtain a sample for measurement. As a measuring device, a nuclear magnetic resonance (NMR) spectrometer (manufactured by Bruker Biospin, AVANCE500 type) was used, 1 the 1H-NMR spectrum was measured, and the quantification of dimethylsiloxane units was performed. For this quantification, a calibration curve was prepared using a deuterated chloroform solution of polydimethylsiloxane as a standard product, and quantification was performed by the multi-point calibration curve method.

[0052] <Talc content in pulp or glass laminated paper> The pulp or glass laminated paper was ashed according to JIS P8251. Next, the talc content (mass %) in the obtained ash was determined by a calibration curve prepared using a glass laminated paper containing a predetermined amount of talc in advance, using a fluorescence X-ray diffractometer (manufactured by Rigaku Corporation, RINT-UltimaIII). The talc content m in the glass laminated paper was determined by the following formula (1). m = (b / a) × c × 100 ··· (1) Here, m: talc content (mass %) a: mass of glass laminated paper (g) b: mass of ash (g) c: talc content in ash (mass %)

[0053] <Glass plate transport test> Foam urethane was laid on the glass placement surface of an aluminum L-shaped pedestal with a 75-degree angle, and 120 glass plates sized 680 mm × 880 mm × 0.7 mm were stacked with glass interleaving paper inserted between each glass plate to form a placement surface for vertically placing the glass plates and a backrest surface extending vertically from the rear end of the placement surface. They were then leaned against the backrest surface so as to be parallel to it. A belt-shaped belt fixed to the pedestal was hung across the entire circumference from the rear end to the backrest surface to fix the glass plates. The pedestal set as described above was covered entirely with packaging materials to prevent the intrusion of dust, dirt, etc. from the outside. Subsequently, a transportation test was conducted by truck over a transportation distance of 1100 km (stored for 5 days in an environment of 40°C × 95% RH during transportation).

[0054] <Performance Evaluation> On the surfaces of the 120 glass plates after the transportation test, linear wirings with a width of 5 μm were formed at intervals of 80 μm by an existing method. Next, the disconnection status of the formed wirings was checked. The performance evaluation was conducted as follows. ○: No disconnection in the wirings of all glass plates. ×: Disconnection in the wirings of multiple glass plates.

[0055] [Example 1] As the raw material pulp, commercially available NBKP (softwood kraft pulp) A without talc was used. In the pulp washing process and bleaching process during the pulp manufacturing process, an oil-in-water (O / W) type silicone-based defoaming agent mainly composed of hydrophilic (water-soluble) modified silicone oil was used. A pulp slurry with a freeness of 450 mlcsf was prepared to obtain pulp with a silicone content of 1.3 mg / kg and a talc content of 0% by mass. Then, using this pulp, papermaking was carried out using a Fourdrinier paper machine without adding papermaking chemicals. After papermaking, it was dried to obtain glass interleaving paper with a basis weight of 50 g / m 2 , a silicone content of 0.2 mg / kg, and a talc content of 0% by mass.

[0056] [Example 2] As the raw material pulp, commercially available NBKP (softwood kraft pulp) B without talc addition was used. In the pulp washing process and bleaching process during the pulp manufacturing process, a water-in-oil (W / O type) silicone-based defoaming agent mainly composed of unmodified silicone oil was used. A pulp slurry with a freeness of 450 mlcsf was prepared to obtain pulp with a silicone content of 0.7 mg / kg and a talc content of 0% by mass. Then, under the same conditions as in Example 1 for other conditions, a glassine paper with a basis weight of 50 g / m 2 and a silicone content of 0.1 mg / kg and a talc content of 0% by mass was obtained.

[0057] [Comparative Example 1] As the raw material pulp, commercially available NBKP (softwood kraft pulp) C without talc addition was used. In the pulp washing process and bleaching process during the pulp manufacturing process, a water-in-oil (W / O type) silicone-based defoaming agent mainly composed of unmodified silicone oil was used. A pulp slurry with a freeness of 450 mlcsf was prepared to obtain pulp with a silicone content of 1.1 mg / kg and a talc content of 0% by mass. Then, under the same conditions as in Example 1 for other conditions, a glassine paper with a basis weight of 50 g / m 2 and a silicone content of 0.8 mg / kg and a talc content of 0% by mass was obtained.

[0058] [Comparative Example 2] As the raw material pulp, commercially available NBKP (softwood kraft pulp) D with talc added was used. In the pulp washing process and bleaching process during the pulp manufacturing process, a water-in-oil (W / O type) silicone-based defoaming agent mainly composed of unmodified silicone oil was used. A pulp slurry with a freeness of 450 mlcsf was prepared to obtain pulp with a silicone content of 1.2 mg / kg and a talc content of 0.7% by mass. Then, under the same conditions as in Example 1 for other conditions, a glassine paper with a basis weight of 50 g / m 2 and a silicone content of 0.9 mg / kg and a talc content of 0.3% by mass was obtained.

[0059] [Comparative Example 3] As the raw material pulp, commercially available NBKP (softwood kraft pulp) E without talc was used. In the pulp washing process and bleaching process during the pulp manufacturing process, a non-emulsion type mineral oil-based defoaming agent was used. A pulp slurry with a freeness of 450 mlcsf was prepared to obtain pulp with a silicone content of 3.5 mg / kg and a talc content of 0% by mass. Thereafter, under the same conditions as in Example 1, a glass laminated paper with a basis weight of 50 g / m 2 was obtained, with a silicone content of 1.8 mg / kg and a talc content of 0% by mass.

[0060]

Table 1

[0061] Table 1 shows the evaluation results of Examples 1 and 2 and Comparative Examples 1 to 3. As a result, in the glass plates laminated using the glass laminated papers of Examples 1 and 2, no disconnection was observed in the wiring of all the glass plates. On the other hand, in the glass plates laminated using the glass laminated papers of Comparative Examples 1 to 3, a plurality of glass plates with disconnection in the wiring were confirmed. From the above results, it became clear that the glass laminated paper of the present invention is effective in suppressing defects such as disconnection caused by contamination.

Claims

1. A pulp for glassine paper containing a hydrophilic modified silicone oil, wherein the content of the hydrophilic modified silicone oil with respect to the pulp is 0.5 to 2 mg / kg as the silicone content, and the pulp for glassine paper is characterized thereby.

2. The hydrophilic modified silicone oil is contained in a silicone-based defoaming agent, and the pulp for glassine paper according to Claim 1, wherein the silicone-based defoaming agent is an oil-in-water type silicone-based defoaming agent.

3. A method for producing glassine paper, wherein in the pulp production process, a silicone-based defoaming agent containing a hydrophilic modified silicone oil is used as a defoaming agent, and the addition rate of the silicone-based defoaming agent with respect to the pulp is 0.5 to 2 mg / kg as the silicone content, and the method for producing glassine paper is characterized thereby.

4. The method for producing glassine paper according to Claim 3, wherein the silicone-based defoaming agent containing the hydrophilic modified silicone oil is an oil-in-water type silicone-based defoaming agent.

5. A glassine paper mainly composed of cellulose pulp, containing a hydrophilic modified silicone oil, The basis weight is 10 to 100 g / m ２ and is a glassine paper wherein the content of the hydrophilic modified silicone oil with respect to the glassine paper is 0.01 to 0.3 mg / kg as the silicone content, and the glassine paper is characterized thereby.

6. The hydrophilic modified silicone oil is contained in a silicone-based defoaming agent, and the glassine paper according to Claim 5, wherein the silicone-based defoaming agent is an oil-in-water type silicone-based defoaming agent.

7. The glassine paper according to Claim 5 or Claim 6, wherein the content of talc added as a pitch control agent is less than 0.1% by mass.

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