JP2005248409A - Insertion paper for glass and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide insertion paper which is used for glass, can easily impart high cleanliness, and can exhibit good workability, and to provide a method for producing the same. <P>SOLUTION: This insertion paper used for glass is characterized by being produced from a paper material obtained by beating natural pulp having an average fiber length of 1.6 to 2.5 mm and containing short fibers having fiber lengths of ≤0.3 mm in an amount of ≤7.0 wt. % until to give a Canadian standard freeness (CSF) of 600 to 750 mL, and having an average fiber length of 1.6 to 2.5 mm. The insertion paper for the glass is inserted between glass substrates, when the glass substrates constituting electric / electronic equipments, especially glass substrates for liquid crystal displays, are handled by laminating to each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a glass interleaving paper used when handling a plurality of glass plates and a method for producing the same, and more particularly to a glass interleaving paper used by being sandwiched between a plurality of glass plates and a method for producing the same.

  Conventionally, when handling in the state which laminated | stacked the several glass plate, in order to suppress malfunctions, such as a damage | wound, on the surface of a glass plate, the slip sheet for glass is used. The slip sheet for glass is used by being sandwiched between a glass plate and a glass plate.

  This type of slip paper for glass has required additives (dispersant, paper strength enhancer, etc.) in order to facilitate its manufacture and improve properties such as strength and smoothness. Moreover, when the recycled pulp reproduced | regenerated from used paper is used, impurities, such as printing ink, are contained in the obtained paper for glass. When the glass interleaving paper is used, additives and impurities may be transferred from the glass interleaving paper to the glass plate surface. Further, when this type of glass interleaving paper decreases in hygroscopicity, transfer of additives and impurities is promoted by moisture in the air. It is known that due to the transfer of such additives and impurities, a portion of the glass plate surface with a reduced cleanliness (called “paper burn” or “paper texture”) is generated.

  In recent years, glass substrates used as substrates for electric / electronic devices are handled in a clean room in order to reduce defects in high vacuum processing such as sputtering and etching processing. As the demand for the quality of the glass substrate becomes stricter, the demand for the quality of the slip sheet for glass used for the glass substrate has also become strict. Matters required for glass interleaving paper include: (1) suppressing the occurrence of paper burn, (2) suppressing the generation of paper dust when removing the glass interleaving paper from the glass substrate, Examples include improving workability, (3) suppressing paper breakage when removing glass interleaving paper from a glass substrate, and improving workability.

  Recently, glass substrates constituting liquid crystal displays, touch panels, and the like are subjected to more precise high vacuum processing and etching processing, and transparent conductors, semiconductors, insulators, and the like are formed on the glass substrates. The matters described in the above (1) and (2) for the glass interleaf used for such a glass substrate are required at a higher level. Furthermore, since the weight of the glass substrate increases as the size of the glass substrate increases, the matter described in (3) above for the glass interleaving paper is required at a higher level.

For the matter described in (1) above, slip sheets with reduced resin content (see Patent Documents 1 to 3) and slip sheets with improved hygroscopicity (refer to Patent Documents 4 to 7) have been proposed. Yes. For the matter described in (2) above, a water-soluble resin was applied to a dust-free paper composed of a manufacturing method (see Patent Document 8) for removing fine fibers at the stage of wet paper or natural pulp and a resin binder. A slip (see Patent Document 9) has been proposed.
Japanese Examined Patent Publication No. 4-79914 Japanese Patent Laid-Open No. 2-53987 Japanese Patent Laid-Open No. 7-101483 Japanese Patent Publication No. 4-60933 Japanese Patent Publication No. 1-332171 Japanese Patent Publication No. 2-40798 JP 7-316998 A JP-A-1-260095 JP-A-9-170198

  However, the slip sheets for glass described in Patent Documents 1 to 7 have a problem that they do not meet the requirements (1) and (2) for recent slip sheets for glass. That is, these glass slip sheets have been proposed for the requirement described in (1) above, and the countermeasures for the requirement (2) are insufficient. Furthermore, recent glass slip sheets are not sufficient for the requirement (1).

  The slip sheet for glass described in Patent Document 8 is proposed for the requirement (2), and the countermeasure for the requirement (1) is insufficient. In addition, since the glass slip sheet described in Patent Document 9 uses a water-soluble resin, it is difficult to say that it is an appropriate measure for the requirements (1) and (2). There was a problem that the level required for slip sheets was not reached.

  That is, the conventional glass slip sheet has a problem that it cannot obtain cleanliness enough to suppress paper burn. Furthermore, there is a problem that the generation of paper dust and paper breakage cannot be sufficiently suppressed, and workability cannot be sufficiently obtained.

  The present invention has been made paying attention to the problems existing in the prior art as described above. The object is to provide a glass interleaving paper that is easy to impart a high degree of cleanliness and that can exhibit good workability, and a method for producing the same.

  In order to achieve the above object, in the interleaving paper for glass according to claim 1, the content of short fibers having an average fiber length of 1.6 to 2.5 mm and a fiber length of 0.3 mm or less is 7.0. It is made from paper stock obtained by beating natural pulp having a weight percent of less than 100% until Canadian Standard Freeness (CSF) is 600 to 750 ml, and has an average fiber length of 1.6 to 2.5 mm. And

In the interleaving paper for glass of the invention described in claim 2, the gist of the invention in claim 1 is that the natural pulp contains 60% by weight or more of softwood bleached kraft pulp.
In the interleaving paper for glass of the invention described in claim 3, the gist of the invention described in claim 1 or claim 2 is that the extract of diethyl ether is 0.1% by weight or less.

  In the interleaving paper for glass of the invention according to claim 4, in the invention according to any one of claims 1 to 3, the tensile strength (T) in the longitudinal direction and the tensile strength (Y) in the transverse direction are All are 10 N or more (15 mm width) or more, and the ratio (ratio = T / Y) of the tensile strength (T) in the longitudinal direction to the tensile strength (Y) in the transverse direction is 1.0 to 3.0. The gist is the range.

In the interleaving paper for glass of the invention according to claim 5, the gist of the invention according to any one of claims 1 to 4 is that the Beck smoothness is 20 seconds or less on both sides.
According to the sixth aspect of the invention, the slip sheet for glass according to the first aspect of the present invention is used by being sandwiched between the glass substrates for liquid crystal displays in the first aspect of the present invention.

  In the manufacturing method of the interleaving paper for glass of invention of Claim 7, average fiber length is 1.6-2.5 mm, and content of the short fiber of fiber length 0.3 mm or less is 7.0 weight% or less. The natural pulp is beaten until the Canadian standard freeness (CSF) reaches 600 to 750 ml to prepare a paper stock, and then the wet paper obtained by making the paper stock is dried by a multi-cylinder dryer. Is the gist.

  According to the present invention, it is easy to impart a high degree of cleanliness and good workability can be exhibited.

Hereinafter, embodiments of the present invention will be described in detail.
The interleaving paper for glass in the present embodiment is obtained by making a paper material using natural pulp as a fiber raw material, and has an average fiber length of 1.6 to 2.5 mm. The average fiber length of natural pulp is 1.6 to 2.5 mm, and the short fiber having a fiber length of 0.3 mm or less in the natural pulp is 7.0% by weight or less. The fiber length here is the length of the fiber in the fiber axis direction. The slip sheet for glass is made from a paper stock obtained by beating until a Canadian standard freeness (CSF) reaches 600 to 750 ml.

  This glass interleaving paper is sandwiched between the glass substrate and the glass substrate when it is handled by laminating a glass substrate for a liquid crystal display, etc. It is used in.

  Natural pulp is a short fibrous material obtained from plants, and is mainly composed of cellulose. Examples of raw materials for this natural pulp include leaf fibers, bast fibers, seed fibers and the like in addition to wood. Examples of the leaf fiber include Manila hemp and sisal hemp, examples of the bast fiber include flax, mulberry, and mitsumata, and examples of the seed fiber include linter. Among the raw materials for natural pulp, wood or bast fibers are preferred because the properties of the glass interleaving paper are easy to adjust and are easily available. Of wood pulp, softwood bleached kraft pulp (N-BKP) or hardwood bleached kraft pulp (L-BKP) is preferable, and bleached manila hemp pulp is preferable among pulps made of bast fibers. Furthermore, since the fiber length is long, it is preferable to contain at least softwood bleached kraft pulp because the required strength is easily imparted to the glass interleaving paper. The content of softwood bleached kraft pulp in the total amount of natural pulp is preferably 60% by weight or more. If the content of the softwood bleached kraft pulp is less than 60% by weight, there is a possibility that sufficient strength cannot be imparted to the interleaving paper for glass.

  As these natural pulps, natural pulp obtained by re-dispersing paper once made can be used. In that case, it is necessary to remove impurities such as resin components and additives such as paper strength enhancers. Natural pulp is preferably 100% virgin pulp because impurities such as resin can be easily removed.

  The average fiber length of natural pulp is 1.6 to 2.5 mm, preferably 1.8 to 2.5 mm, and more preferably 1.9 to 2.5 mm. If the average fiber length is less than 1.6 mm, sufficient strength cannot be obtained. On the other hand, if the thickness exceeds 2.5 mm, binding (a lump of fibers that have not been disaggregated) occurs in a part of the interleaf paper for glass, and the texture deteriorates. Therefore, when laminating the glass interleaving paper and the glass substrate, the adhesion of the glass interleaving paper to the glass substrate is lowered. Therefore, the glass substrate is easily displaced and workability is deteriorated. Further, in the laminated glass substrate, stress is partially generated by the binding, and there is a possibility that the glass substrate is distorted.

  The short fiber having a fiber length of 0.3 mm or less in the natural pulp is 7.0% by weight or less, preferably 6.0% by weight or less, more preferably 5.0% by weight or less. When the content of the short fibers exceeds 7.0% by weight, fluffing occurs on the surface of the glass interleaving paper, and thus generation of paper dust cannot be suppressed. The average fiber length and short fiber content are measured by an image analysis method using a fiber quality analyzer (LDA96, manufactured by Optest Equipment).

  The stock is obtained by beating the natural pulp until the Canadian standard freeness (CSF) reaches 600 to 750 ml. If the CSF is less than 600 ml, fine fibers increase, and thus generation of paper dust cannot be suppressed. Moreover, since the freeness falls, there is a possibility that papermaking becomes difficult, and it is difficult to set the average fiber length and the short fiber content. On the other hand, if it exceeds 750 ml, the fibrillation is insufficient and the strength required for the interleaving paper for glass cannot be obtained. The CSF is measured according to JIS P 8121. Various refiners such as various beaters, conicals, and disks can be used to beat this natural pulp.

  This paper stock contains water and the like in addition to the beaten natural pulp, but it is not necessary to contain substantially organic chemicals. The organic chemical referred to here is a chemical composed of an organic compound, and specifically includes a paper strength enhancer, a dispersant, a sizing agent, a filler, and the like. For example, a polyacrylamide polymer compound, starch, a water-soluble polymer. (Polyvinyl alcohol, etc.). The obtained slip paper for glass is preferably 0.1% by weight or less, more preferably 0.09% by weight or less, and still more preferably 0.08% by weight or less, by extraction with diethyl ether. If this extract exceeds 0.1% by weight, the content of organic chemicals and the like becomes high, and it may be difficult to exhibit a high degree of cleanliness. In addition, the extract by diethyl ether is measured based on JIS P8205.

  This stock is dispersed and diluted to a concentration suitable for the paper machine and paper making method used. As a paper machine, it is possible to use a long net, a short net, a deformation type of these, and a deformation type of a circular net. When the thickness of the interleaving paper for glass is 100 μm or less, the texture and smoothness can be easily controlled, and therefore, a slanted wire that is a short mesh deformation type or a dry mesh deformation type that is a circular mesh deformation type is preferable. The dry method is a system in which a stock inlet (stock stirring tank) for paper stock is directly installed on a circular net and the paper stock flows on the net.

  The wet paper obtained by making the paper is squeezed by a press part and then dried by a dryer. Examples of the dryer include a Yankee dryer and a multi-cylinder dryer. A Yankee type dryer is a dryer that dries one side of a wet paper with the surface of the wet paper in close contact with the dryer surface. The multi-cylinder dryer is a dryer in which both sides of a wet paper are alternately brought into close contact with a dryer surface and dried stepwise. Among these dryers, it is preferable to use a multi-cylinder dryer because moderate smoothness can be imparted to the front and back surfaces of the interleaving paper for glass. Moreover, when using a multi-cylinder dryer, it is preferable to maintain the moisture content of the wet paper in the first cylinder at 65% by weight or more. When the moisture content is less than 65% by weight, the smoothness on both surfaces of the glass interleaving paper varies, and the laminated glass substrates may be easily displaced.

  The Beck smoothness of the obtained slip paper for glass is preferably 20 seconds or less, more preferably 18 seconds or less, and most preferably 16 seconds or less for both front and back. If this Beck smoothness exceeds 20 seconds, the glass slip sheet is likely to adhere to the glass substrate due to static electricity or the like, and it may be difficult to place the glass slip sheet on the glass substrate. On the other hand, if the Beck smoothness exceeds 20 seconds, the hygroscopicity is lowered and paper burns may occur. The Beck smoothness is measured according to JIS P 3119.

  The tensile strength (T) in the longitudinal direction and the tensile strength (Y) in the transverse direction of the interleaving paper for glass are both 10 N or more (15 mm width), and the tensile strength in the transverse direction of the tensile strength (T) in the longitudinal direction. The ratio to (Y) (ratio = T / Y) is preferably in the range of 1.0 to 3.0, and more preferably in the range of 1.0 to 2.5. Here, the vertical direction means the flow direction of the paper machine, and the horizontal direction means the width direction of the paper machine. When this tensile strength (T, Y) is less than 10 N (15 mm width), the strength required for a slip sheet for glass cannot be obtained sufficiently. Further, glass slip sheets having a ratio of tensile strength (T) to tensile strength (Y) of less than 1.0 cannot be easily produced. On the other hand, if this ratio exceeds 3.0, the anisotropy in the strength between the vertical direction and the horizontal direction is high, so that there is a risk that wrinkles and tears are likely to occur during use.

  Now, in order to manufacture a glass interleaving paper, a natural pulp having an average fiber length of 1.6 to 2.5 mm and a short fiber content of 0.3 mm or less is prepared by 7.0 wt% or less. . Paper stock is prepared by beating this natural pulp until the CSF reaches 600-750 ml. By making this paper with a paper machine, a slip sheet for glass is produced. This interleaving paper for glass is used by being sandwiched between glass substrates. At this time, since the interleaving paper for glass is made from a paper material beaten from the above-mentioned natural pulp, a predetermined strength is imparted without using an organic chemical such as a paper strength enhancer. That is, when it is used by being sandwiched between glass substrates, strength sufficient to withstand is given. In addition, since it is not necessary to use organic chemicals, the cleanliness of the interleaving paper for glass is sufficiently ensured. Furthermore, since the content of short fibers is set in the above range and the CSF is set in the above range, dropping of fine fibers, which are mainly fibrillated fibers from the glass interleaving paper, is suppressed. That is, the generation of paper dust during use of the glass slip sheet is reduced as much as possible.

The effects exhibited by this embodiment will be described below.
-In the slip sheet for glass of this embodiment, natural pulp having an average fiber length of 1.6 to 2.5 mm and a short fiber content of 0.3 mm or less is 7.0% by weight or less. Yes. The paper stock is obtained by beating the natural pulp until the CSF reaches 600 to 750 ml. The slip sheet for glass is made from the stock and has an average fiber length of 1.6 to 2.5 mm. When comprised in this way, predetermined intensity | strength is provided even if it does not use an organic chemical | medical agent. Moreover, since content of a short fiber is 7.0 weight% or less, generation | occurrence | production of paper dust is suppressed. Accordingly, it is possible to suppress the generation of paper dust and paper breakage during the operation of sandwiching the glass interleaving paper into the glass substrate and removing the glass interleaving paper from the glass substrate. In addition, since it is not necessary to use an organic chemical during papermaking, the cleanliness of the glass interleaving paper is ensured. Therefore, it is easy to impart a high degree of cleanliness and good workability can be exhibited. Therefore, if this glass interleaving paper is used, the productivity of an electric / electronic device provided with a glass substrate can be improved, and the production cost can be reduced.

  In the glass interleaving paper of this embodiment, it is preferable that the natural pulp contains 60% by weight or more of softwood bleached kraft pulp. When comprised in this way, it is easy to set an average fiber length to the said range, and can obtain the intensity | strength required as a slip sheet for glass easily.

  -In the slip paper for glass of this embodiment, it is preferable that the extract by diethyl ether is 0.1 weight% or less. When comprised in this way, a high degree of cleanliness can be exhibited and defects, such as paper burns, in a glass substrate can be reduced as much as possible.

  In the glass slip sheet of this embodiment, the tensile strength (T, Y) is 10 (N / 15 mm width) or more and the ratio of the tensile strength (T) to the tensile strength (Y) (ratio = T / Y) is preferably in the range of 1.0 to 3.0. When configured in this way, the glass interleaving paper may be wrinkled or torn during the operation of sandwiching the glass interleaving paper into the glass substrate or removing the glass interleaving paper from the glass substrate. This can be further suppressed and workability can be further improved. In particular, when this glass interleaving paper is made flat and an operator manually handles the square glass interleaving paper, since the anisotropy in the strength of the glass interleaving paper is reduced, the glass interleaving paper Occurrence of wrinkles and paper breaks can be effectively suppressed, and work efficiency can be improved.

  In the glass slip sheet of this embodiment, it is preferable that the Beck smoothness is 20 seconds or less on both the front and back sides. When comprised in this way, since the smoothness in the front and back surfaces of the interleaving paper for glass is moderately adjusted, it can be made to fit along a glass substrate easily. Therefore, it can be easily sandwiched between the glass substrates, and workability can be further improved. Moreover, since smoothness is adjusted moderately, the hygroscopic property in the front and back of glass interleaving paper is ensured. Therefore, paper burn caused by moisture on the front and back surfaces of the glass substrate can be suppressed.

  In the glass slip sheet of this embodiment, it is preferably used for a glass substrate for a liquid crystal display. When comprised in this way, a high degree of cleanliness and favorable workability | operativity are fully exhibited, and the malfunction of a glass substrate can be reduced. Recently, as the size of liquid crystal displays increases, the weight of the glass substrate increases. Even in such a glass substrate, good workability can be exhibited.

  -In the manufacturing method of the interleaving paper for glass of this embodiment, the wet paper obtained by making the said paper stock is dried with the multi-cylinder dryer. In the case of this manufacturing method, moderate smoothness can be imparted to the front and back surfaces of the interleaving paper for glass, and variations in the smoothness of the front and back surfaces can be suppressed.

Next, the embodiment will be described more specifically with reference to production examples and comparative examples.
(Production Example 1)
N-BKP (average fiber length of 2.35 mm, short fiber of 0.3 mm or less, 4.8 wt%) was used as natural pulp, and 2.5 parts by weight of a sulfuric acid band was added to 100 parts by weight of this natural pulp. This was beaten with a double disc refiner (DDR) to 650 ml of CSF to prepare a stock. The paper stock was made with an inclined wire so that the ratio of the tensile strength (T) to the tensile strength (Y) was about 2.0. The obtained wet paper was dried using a multi-cylinder dryer so that the wet water content of the first tube was adjusted to 75% by weight and dried.
(Production Example 2)
Natural pulp was prepared by adding 10 parts by weight of L-BKP (average fiber length of 0.9 mm, short fiber of not more than 0.3 mm, 4.4% by weight) to 90 parts by weight of N-BKP described in Production Example 1. Glass interleaving paper was produced from this natural pulp in the same manner as in Production Example 1.
(Production Example 3)
A blend of 90% by weight of N-BKP described in Production Example 1 with Manila hemp pulp (average fiber length of 3.45 mm, 0.2% by weight of short fibers of 0.3 mm or less) was used as a natural pulp. Glass interleaving paper was produced from this natural pulp in the same manner as in Production Example 1 except that CSF was beaten to 660 ml.
(Production Example 4)
A glass interleaving paper was produced in the same manner as in Production Example 2, except that 70 parts by weight of N-BKP and 30 parts by weight of L-BKP were used as natural pulp.
(Production Example 5)
A slip sheet for glass was produced in the same manner as in Production Example 3, except that 70 parts by weight of N-BKP and 30 parts by weight of Manila hemp pulp were used as natural pulp.
(Production Example 6)
Glass interleaving paper was produced in the same manner as in Production Example 1, except that a paper machine was used instead of the slanted wire as a paper machine, using a dry type paper machine (Lot former, manufactured by Sandy Hill).
(Production Example 7)
Glass interleaving paper was produced in the same manner as in Production Example 1 except that the paper was made using a long paper machine instead of the inclined wire as the paper machine.
(Comparative Example 1)
A glass interleaving paper was produced in the same manner as in Production Example 1 from natural pulp in which 50 parts by weight of N-BKP described in Production Example 1 was blended with 50 parts by weight of L-BKP described in Production Example 2.
(Comparative Example 2)
A slip sheet for glass was produced in the same manner as in Production Example 3 except that 50 parts by weight of N-BKP and 50 parts by weight of Manila hemp pulp were used as natural pulp.
(Comparative Example 3)
Glass interleaving paper was produced in the same manner as in Production Example 1 except that the CSF was beaten until it reached 550 ml.
(Comparative Example 4)
A glass interleaving paper was produced in the same manner as in Production Example 2 except that 50 parts by weight of N-BKP and 50 parts by weight of waste paper were mixed with natural pulp.
(Reference Example 1)
A slip sheet for glass was produced in the same manner as in Production Example 1 except that the paper was made with an inclined wire so that the ratio of the tensile strength (T) to the tensile strength (Y) was about 4.1. .
(Reference Example 2)
Glass interleaving paper was produced in the same manner as in Production Example 1 except that a Yankee dryer was used instead of the multi-cylinder dryer, and one side of the wet paper was brought into close contact with the dryer surface and dried.
(Measurement of physical properties)
(A) Average fiber length of natural pulp and short fiber content of 0.3 mm or less It was measured by an image analysis method using a fiber quality analyzer (LDA96, manufactured by Optest Equipment).

(B) Canadian Standard Freeness (CSF)
The measurement was performed according to JIS P 8121.
(C) Basis weight of interleaving paper for glass Measured according to JIS P 8124.

(D) Tensile strength of interleaving paper for glass It was measured using an outer micrometer (manufactured by Mitutoyo Corporation) in accordance with JIS P 8118.
(E) Beck smoothness Based on JIS P 3119, it was measured using a Beck smoothness tester (manufactured by Toyo Seiki Co., Ltd.).

(F) Resin content Based on JIS P 8205, the content of the extract by diethyl ether was measured.
(Evaluation methods)
(Evaluation 1) Paper Discoloration Two glass substrates (100 mm × 200 mm) used for a liquid crystal display were prepared, and a glass interleaving paper was sandwiched between the glass substrates. Next, the glass substrate was left to stand for 120 hours in an atmosphere of 50 ° C. and a relative humidity of 95% under a load of 100 g. Thereafter, the glass interleaving paper was removed from the glass substrate, and the glass surface with which the glass interleaving paper was in contact was visually observed. A sample in which no cloudiness or foreign matter remained was defined as “good: ◯”, and a sample in which cloudiness or foreign matter remained was defined as “defective: x”.

(Evaluation 2) Along the glass substrate Two glass substrates (1000 mm × 1000 mm) used for the liquid crystal display were prepared, and a glass interleaving paper was sandwiched between the glass substrates. At that time, the ease of alignment of the slip sheet for the glass with respect to the glass substrate was evaluated. The slip of the slip sheet for glass on the glass substrate is moderately adjusted, and “good: ○” is easily along the glass substrate, slipping of the slip sheet for glass on the glass substrate becomes excessive or insufficient, and from the glass substrate A sample in which deviation is likely to occur is defined as “defect: x”.

(Evaluation 3) Generation | occurrence | production of wrinkles Two glass substrates (1000 mm x 1000 mm) used for a liquid crystal display were prepared, and the glass interleaving paper was inserted | pinched between the glass substrates. At that time, the case where no wrinkle was generated on the interleaving paper for glass was defined as “good: ○”, and the case where wrinkle was generated was defined as “defective: ×”.

(Evaluation 4) Occurrence of Bundling The number of bindings present in the glass interleaving paper 1000 m ² was 2 or less as “good: ◯”, and the number exceeding 2 as “bad: x”.

The evaluation results of each example are shown in Table 2.
The measurement results of physical properties in each example are shown in Table 1, and the evaluation results are shown in Table 2.

表１の結果から、製造例１〜７では樹脂分が０．１重量％以下の値を示し、ガラス用合紙に高度な清浄性が付与されることがわかる。従って、表２に示す評価１について良好な結果が得られている。また、製造例１〜７では評価２〜４の結果が良好であることから、良好な作業性が発揮されることがわかる。加えて、製造例１〜７ではガラス用合紙の表裏面に毛羽立ちが発生しないため、紙粉の発生が抑制されている。

From the results of Table 1, it can be seen that in Production Examples 1 to 7, the resin content shows a value of 0.1% by weight or less, and a high degree of cleanliness is imparted to the glass interleaving paper. Therefore, good results are obtained for evaluation 1 shown in Table 2. Moreover, since the result of evaluation 2-4 is favorable in manufacture examples 1-7, it turns out that favorable workability | operativity is exhibited. In addition, in Production Examples 1 to 7, since the fluff does not occur on the front and back surfaces of the glass interleaving paper, the generation of paper dust is suppressed.

  In Comparative Example 1, since the average fiber length is less than 1.6 mm, the fine fibers fall off from the front and back surfaces of the interleaving paper for glass, and the generation of paper dust cannot be suppressed. In Comparative Example 2, since the average fiber length exceeds 2.5 mm, it is understood that the evaluation 4 is poor and the workability is deteriorated. In Comparative Example 3, since the CSF is less than 600 ml, fluffing on the front and back surfaces occurs and evaluation 1 is poor. In Comparative Example 4, since the short fiber exceeds 7.0% by weight, fluffing on the front and back surfaces occurs, and the evaluation 1 is poor. In Reference Example 1, since the tensile strength ratio (T / Y) exceeds 3.0, the evaluation 3 is poor. In Reference Example 2, since a Yankee dryer was used, the surface Beck smoothness exceeded 20 seconds. Therefore, evaluation 1 and evaluation 2 are defective.

Claims (7)

Natural pulp having an average fiber length of 1.6 to 2.5 mm and a short fiber content of 0.3 mm or less of 7.0% by weight or less has a Canadian standard freeness (CSF) of 600 to 750 ml. A glass interleaving paper, which is made from a paper stock obtained by beating up to and having an average fiber length of 1.6 to 2.5 mm. The said natural pulp is a paper for glass of Claim 1 which contains 60 weight% or more of softwood bleached kraft pulp. The glass interleaving paper according to claim 1 or 2, wherein an extract of diethyl ether is 0.1% by weight or less. The tensile strength (T) in the longitudinal direction and the tensile strength (Y) in the transverse direction are both 10N or more (15 mm width) and the tensile strength (Y) in the transverse direction of the tensile strength (T) in the longitudinal direction. The glass interleaving paper according to any one of claims 1 to 3, wherein a ratio (ratio = T / Y) to is in a range of 1.0 to 3.0. The interleaving paper for glass according to any one of claims 1 to 4, wherein the Beck smoothness is 20 seconds or less on both sides. The interleaving paper for glass according to any one of claims 1 to 5, wherein the interleaving paper is used by being sandwiched between glass substrates for liquid crystal displays. Natural pulp having an average fiber length of 1.6 to 2.5 mm and a short fiber content of not more than 0.3 mm is 7.0% by weight or less, with a Canadian standard freeness (CSF) of 600 to 750 ml. A method for producing glass interleaving paper, characterized in that a paper stock is prepared by beating until a wet paper obtained by papermaking the stock is dried by a multi-cylinder dryer.