JP2019064048A - Laminated paper for glass plate - Google Patents

Abstract

To provide laminated paper for glass plate which prevents contamination of a glass plate.SOLUTION: Laminated paper 1 for glass plate has a thermoplastic resin foam layer 10, an antistatic layer 20 and a thermoplastic resin non-foam layer 30 in this order, where a center line average roughness in an MD direction measured according to JIS B0601(1982) on the surface on the thermoplastic resin non-foam layer 30 side is 10 μm or more, and a center line average roughness in a TD direction measured according to JIS B0601(1982) on the surface on the thermoplastic resin non-foam layer 30 side is 10 μm or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an interleaf for glass plates.

During transport or storage of glass plates for flat panel displays such as liquid crystal displays and plasma displays, glass plates are used for the purpose of preventing adhesion of foreign matter to the glass plates and preventing rubbing between the glass plates. An interleaf sheet is used.
Patent Document 1 proposes a glass sheet paper made of a multi-layer foam sheet having a polyethylene resin foam layer and an antistatic layer on both sides thereof.

Unexamined-Japanese-Patent No. 2016-135582

  However, in the case of the interleaf paper for glass plate of Patent Document 1, since the antistatic layer is on the surface, it is easily scraped off, and there is a possibility that scraps adhere to the glass plate. In addition, there is a possibility that the antistatic agent may adhere to the glass plate, and there is a problem that the glass plate is easily contaminated.

  This invention is made in view of the said situation, and it aims at providing the paper for glass plates which is hard to contaminate a glass plate.

  As a result of intensive investigations, the present inventors have a thermoplastic resin foam layer, an antistatic layer, and a thermoplastic resin non-foam layer in this order, and the center line average roughness of the thermoplastic resin non-foam layer is It has been found that the above-mentioned problems can be solved by using the interleaf sheet for glass plate which is within the specific range.

The present invention has the following aspects.
[1] having a thermoplastic resin foam layer, an antistatic layer, and a thermoplastic resin non-foam layer in this order,
The center line average roughness in the MD direction measured according to JIS B 0601 (1982) on the surface of the thermoplastic resin non-foamed layer side is 10 μm or more,
The paper for glass plates whose center line average roughness of the TD direction measured according to JIS B0601 (1982) on the surface of the thermoplastic resin non-foamed layer side is 10 μm or more.
[2] The paper for glass plate according to [1], wherein the antistatic layer contains a reaction product of a (meth) acrylic resin and a curing agent.
[3] The paper for glass plates as described in [1] or [2] whose 10% compressive strength calculated | required by JISK6767 is 0.1-0.5 MPa.
[4] The paper for glass plates according to any one of [1] to [3], wherein the 50% compressive strength determined by JIS K6767 is 0.3 to 0.7 MPa.
[5] The paper for glass plates according to any one of [1] to [4], wherein the thickness of the non-foamed thermoplastic resin layer is 10 to 50 μm.

  ADVANTAGE OF THE INVENTION According to this invention, the paper for glass plates which is hard to contaminate a glass plate can be provided.

It is sectional drawing which shows an example of the paper for glass plates of this invention. It is a schematic diagram which shows an example of the manufacturing apparatus of a foam sheet.

«Orange paper for glass plate»
The paper sheet for glass plates of the present invention has a thermoplastic resin foam layer, an antistatic layer, and a thermoplastic resin non-foam layer in this order. By the antistatic layer being between the thermoplastic resin foam layer and the thermoplastic resin non-foam layer, it is possible to prevent the glass plate from being contaminated without directly touching the glass plate.
The glass sheet interleaf paper 1 of FIG. 1 comprises a thermoplastic resin foam layer 10, an antistatic layer 20 provided on one surface of the thermoplastic resin foam layer 10, and a thermal layer provided on the antistatic layer 20. And a plastic resin non-foaming layer 30. The glass interleaf 1 has a three-layer structure, and the thermoplastic resin non-foamed layer 30 is located on the surface.
In FIG. 1, the thickness method is enlarged and illustrated.

<Thermoplastic resin foam layer>
The thermoplastic resin foam layer (hereinafter, also simply referred to as "foam layer") is formed by foaming of the resin composition. The resin composition contains a thermoplastic resin and a foaming agent. As a thermoplastic resin, a polystyrene resin, a polyolefin resin, and a polyester resin are preferable.

As a polystyrene resin, the homopolymer or copolymer of a styrene-type monomer, the copolymer of a styrene-type monomer and another vinyl-type monomer, or these mixtures etc. are mentioned, for example. A polystyrene resin may be used individually by 1 type, and 2 or more types may be combined and used.
The polystyrene resin preferably contains 50% by mass or more, and more preferably 70% by mass or more, of structural units based on a styrene-based monomer, based on the total structural units of the polystyrene resin. It is more preferable that the material is contained by mass% or more.
Further, the mass average molecular weight of the polystyrene resin is preferably 200,000 to 400,000, and more preferably 240,000 to 400,000. The said mass mean molecular weight is the value which converted the value measured by GPC (gel permeation chromatography) based on the calibration curve by standard polystyrene.

Examples of homopolymers or copolymers of the above-mentioned styrene-based monomers include styrene-based monomers such as styrene, α-methylstyrene, vinyltoluene, chlorostyrene, ethylstyrene, i-propylstyrene, dimethylstyrene and bromostyrene. There may be mentioned homopolymers or copolymers of monomers. Among these, those having a structural unit based on styrene in an amount of 50% by mass or more based on all the structural units are preferable, and polystyrene is more preferable.
Further, high impact polystyrene containing a rubber component may be used as the polystyrene resin.

As a copolymer of a styrene-based monomer and another vinyl-based monomer, for example, styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid ester copolymer, styrene-vinyl chloride Copolymer, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, styrene-maleic acid ester copolymer, styrene-fumaric acid ester copolymer, styrene-divinylbenzene copolymer A polymer, a styrene-alkylene glycol dimethacrylate copolymer, a (meth) acrylic acid ester-butadiene-styrene copolymer (for example, MBS resin) etc. are mentioned.
In the present specification, (meth) acrylic acid means acrylic acid or methacrylic acid.

  As a copolymer of a styrene-based monomer and another vinyl-based monomer, one containing a constitutional unit based on a styrene-based monomer in an amount of 50% by mass or more based on the total constitutional units of the copolymer Preferably, those containing 70% by mass or more are more preferable, and those containing 80% by mass or more are more preferable.

As a copolymer of a styrene-based monomer and another vinyl-based monomer, a styrene- (meth) acrylic acid copolymer and a styrene-butadiene copolymer are preferable. Examples of the styrene- (meth) acrylic acid copolymer include styrene-acrylic acid copolymer and styrene-methacrylic acid copolymer.
As the styrene- (meth) acrylic acid copolymer, one having a content of a structural unit based on (meth) acrylic acid in the copolymer is 1 to 14% by mass with respect to all the structural units of the copolymer Is preferable, one having 1% by mass or more and less than 14% by mass is more preferable, and one having 4 to 10% by mass is more preferable.
As the styrene-butadiene copolymer, one having a content of a constituent unit based on butadiene in the copolymer is preferably 1 to 14% by mass with respect to the total constituent units of the copolymer, and 1 to 14% by mass. Those having less than% by mass are more preferable, and those having 4 to 10% by mass are more preferable.

The content of the structural unit based on (meth) acrylic acid in the polystyrene resin is preferably 0.5 to 6.8% by mass with respect to all the structural units constituting the polystyrene resin, and 1.0 to 5. 0 mass% is more preferable, and 1.3 to 3.0 mass% is more preferable. By being in the above numerical range, excellent toughness and heat resistance can be exhibited.
The content of the structural unit based on (meth) acrylic acid in the polystyrene resin can be calculated by calculation from the charged amount of styrene- (meth) acrylic acid.

As for content of the structural unit based on butadiene in polystyrene resin, 0.5-6.8 mass% is preferable with respect to all the structural units which comprise a polystyrene resin, 1.0-5.0 mass% More preferably, 1.3 to 3.0% by mass is more preferable. By being in the above numerical range, excellent toughness and heat resistance can be exhibited.
The content of the structural unit based on butadiene in the polystyrene resin can be calculated from the amount of styrene-butadiene charged.

The content of the styrene- (meth) acrylic acid copolymer in the polystyrene resin is preferably 10% by mass or more based on the total mass of the polystyrene resin. When the content of the styrene- (meth) acrylic acid copolymer is equal to or more than the above lower limit value, it is easy to enhance the fusion property.
The content of the styrene- (meth) acrylic acid copolymer in the polystyrene resin is not particularly limited, and may be 100% by mass with respect to the total mass of the polystyrene resin.

The content of the styrene-butadiene copolymer in the polystyrene resin is preferably 10% by mass or more based on the total mass of the polystyrene resin. When the content of the styrene-butadiene copolymer is equal to or more than the above lower limit value, it is easy to improve the fusion property.
The content of the styrene-butadiene copolymer in the polystyrene resin is not particularly limited, and may be 100% by mass with respect to the total mass of the polystyrene resin.

  As polystyrene resins, commercially available polystyrene resins, polystyrene resins synthesized by a suspension polymerization method, etc., polystyrene resins (virgin polystyrene) which are not recycled materials can be used, and polystyrene foams already used, polystyrene resins The recycled raw material obtained by reprocessing resin foam molded articles (trays for food packaging etc.) etc. can be used. Examples of the recycled raw materials include recycled raw materials obtained by recovering used polystyrene foams and polystyrene resin foam molded bodies and regenerating them by a limonene dissolution method or a heating volume reduction method.

  Examples of polyolefin resins include polypropylene resins, polyethylene resins, cyclic polyolefin resins and the like. The polyolefin resins may be used alone or in combination of two or more.

  As the polypropylene-based resin, for example, a homopolymer of propylene (homoPP), a random copolymer of ethylene and propylene copolymerized (random PP), a homopolymer of polypropylene, and the like are prepared. The block copolymer (block PP) etc. which copolymerized ethylene are mentioned.

As the polyethylene resin, for example, low density polyethylene resin (LDPE) in which ethylene is polymerized under high pressure to form long chain branches in the molecule, ethylene is polymerized under medium and low pressure using Ziegler Natta catalyst or metallocene catalyst High density polyethylene resin (HDPE) having a density of 0.942 g / cm ³ or more, and a small amount of α-olefin such as 1-butene, 1-hexene, 1-octene or the like added in the polymerization process of the HDPE Examples thereof include linear low density polyethylene resin (LLDPE) having a density of less than 0.942 g / cm ^{3 in} which short chain branches are formed.

  Examples of the cyclic polyolefin resin include a copolymer (COC) of ethylene and norbornene, and a polymer (COP) obtained by polymerizing cyclopentanediol by a metathesis reaction.

  50 mass% or more is preferable with respect to all the structural units which comprise polyolefin resin, and, as for content of the structural unit based on propylene in polyolefin resin, 80 mass% or more is more preferable. The entire amount of the polyolefin resin may be a polypropylene resin.

  Examples of polyester resins include polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polyethylene furanoate resin, polybutylene naphthalate resin, copolymers of terephthalic acid, ethylene glycol and cyclohexane dimethanol, and mixtures thereof, and mixtures thereof Mixtures of these with other resins may, for example, be mentioned. Also, plant-derived polyethylene terephthalate resin and polyethylene furanoate resin may be used. The polyester resins may be used alone or in combination of two or more.

The resin composition contains a foaming agent.
Examples of the blowing agent include hydrocarbons such as propane, butane and pentane. Among them, butane is preferred, and a mixture of normal butane and isobutane is preferred. These foaming agents may be used alone or in combination of two or more.
When a mixture of isobutane and normal butane is used as a foaming agent, the mass ratio represented by isobutane: normal butane is preferably 80:20 to 55:45, and more preferably 70:30 to 60:40. If the proportion of isobutane is equal to or more than the above lower limit, the temporal deterioration of the secondary foamability in the foam layer is suppressed, and if it is less than the above upper limit, the maturation period of the foam layer can be shortened until the container and the like are formed. .

The content of the foaming agent in the resin composition is appropriately determined in consideration of the type of the foaming agent, specific gravity, etc. For example, 0.5 to 6.0 parts by mass is preferable with respect to 100 parts by mass of the resin, 0.8 to 5.5 parts by mass is more preferable.
0.3-3.6 mass% is preferable with respect to the gross mass of a foaming layer, and, as for content (the so-called residual gas amount) of the foaming agent in a foaming layer, 0.5-3.3 mass% is more preferable.

  The resin composition includes other resins, surfactants, cell regulators, crosslinking agents, fillers, flame retardants, flame retardant aids, lubricants (hydrocarbons, fatty acids, fatty acid amides, esters, alcohols, metals) Additives such as soap, silicone oil, waxes such as low molecular weight polyethylene, spreading agents (liquid paraffin, polyethylene glycol, polybutene etc.), coloring agents may be added.

  Examples of other resins include (meth) acrylic resins, acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, polyphenylene ether resins, and the like.

Examples of the cell regulator include talc, sodium hydrogencarbonate, ammonium hydrogencarbonate, calcium carbonate, clay, citric acid and the like. Among them, talc is preferred.
The cell regulator may be used alone or in combination of two or more.
The addition amount of the air bubble regulator is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the resin.

The thickness _{T 1} of the foam layer is suitably determined in accordance with the determined strength or the like, for example, preferably 0.5 to 1.5 mm, 0.6 to 1.2 mm is more preferable. When the thickness of the foam layer is within the above-mentioned numerical range, the interleaf for glass plate is excellent in bending strength, and the handleability is improved.
In the present specification, the thickness is a value obtained by measuring 20 points at regular intervals in the width direction (TD direction) of the object to be measured with a macro gauge and calculating the arithmetic mean value thereof.

The apparent density of the expanded layer is preferably ^{0.1~0.4g / cm 3, 0.13~0.2g / cm} 3 is more preferable. When the apparent density of the foam layer is within the above numerical range, the handling property is excellent.

70-500 g / m < ² > is preferable and, as for the basic weight of a foam layer, 100-400 g / m < ² > is more preferable. When the basis weight of the foam layer is within the above numerical range, the handleability is excellent.
The basis weight can be measured by the following method.
10 pieces of 10 cm × 10 cm pieces are cut out at equal intervals in the width direction except for 20 mm at both ends in the width direction of the foam layer, and the mass (g) of each piece is measured to 0.001 g unit. A value of the average value was converted into mass per 1 m ² of the mass (g) of each section, the basis weight of the foam layer (g / m ^2).

<Production method of foam sheet>
The foam sheet which forms a foam layer is manufactured according to the conventionally well-known manufacturing method.
Examples of the method for producing a foam sheet include a method of preparing a resin composition, extruding the resin composition into a sheet, and foaming (primary foaming) (extrusion and foaming method).
An example of a method for producing a foam sheet will be described with reference to FIG.
The foam sheet manufacturing apparatus 200 of FIG. 2 is an apparatus for obtaining a foam sheet by inflation molding, and includes an extruder 202, a foaming agent supply source 208, a circular die 210, a mandrel 220, and two winding machines 240. Equipped with
The extruder 202 is a so-called tandem-type extruder, and is configured such that a first extrusion unit 202 a and a second extrusion unit 202 b are connected by a pipe 206. The first extruding unit 202a includes a hopper 204, and a foaming agent supply source 208 is connected to the first extruding unit 202a.
The circular die 210 is connected to the second extruding unit 202 b, and a mandrel 220 is provided downstream of the circular die 210. The mandrel 220 is provided with a cutter 222.

  First, the raw material which comprises a resin composition is supplied from the hopper 204 to the 1st extrusion part 202a. The raw materials supplied from the hopper 204 are a resin constituting the foam sheet, and an additive which is blended as needed.

In the first extrusion unit 202a, the raw materials are mixed while heating to an arbitrary temperature to form a resin melt, and the foaming agent is supplied from the foaming agent supply source 208 to the first extrusion unit 202a, and the foaming agent is added to the resin melt Are mixed to form a resin composition.
The heating temperature is appropriately determined in the range in which the resin is melted and the additive is not modified in consideration of the type of the resin and the like.

The resin composition is supplied from the first extruding unit 202 a to the second extruding unit 202 b through the pipe 206, further mixed, cooled to an arbitrary temperature, and then supplied to the circular die 210. The temperature of the resin composition at the time of extruding from the circular die 210 is 140 to 190 ° C., more preferably 150 to 190 ° C.
The resin composition is extruded from the circular die 210, and the foaming agent foams to form a cylindrical foam sheet 101a. The foamed sheet 101 a extruded from the circular die 210 is supplied to the mandrel 220 after being blown with the cooling air 211. The cooling rate of the foam sheet 101 a can be adjusted by the combination of the temperature, the amount, and the spraying position of the cooling air 211.
The cylindrical foam sheet 101 a is brought to an arbitrary temperature with a mandrel 220, sized, and cut into two sheets by a cutter 222 to form the foam sheet 101. The foam sheet 101 is wound around the guide roll 242 and the guide roll 244, and taken up by the winder 240 to form the foam sheet roll 102.
The foaming ratio of the foam sheet is, for example, 2 to 20 times.
In addition, a foam sheet may be manufactured by methods other than inflation molding.

<Antistatic layer>
The antistatic layer is made of a cured product of an antistatic agent containing a resin and a curing agent. The cured product is a reaction product of a resin and a curing agent. As the resin, a (meth) acrylic resin having a structure represented by the following formula (1) is preferable. The term "(meth) acrylic" as used herein means either or both of "methacrylic" and "acrylic".

(In formula (1), R ¹ and R ³ are each independently an alkyl group of 1 to 5 carbon atoms, R ² is an alkylene group of 1 to 5 carbon atoms, and R ⁴ is 1 to 2 carbon atoms Is an alkylene group of

The (meth) acrylic resin can be obtained by polymerizing an acrylic monomer.
It is preferable that the structural unit which has a structure represented by the said Formula (1) is derived | led-out from the (meth) acrylic acid ester monomer which has a structure represented by said (1).
Other acrylic monomers include maleic anhydride, (meth) acrylamide, (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, itaconic anhydride, crotonic acid, ethyl (meth) acrylate, (meth) acrylic acid Acid methyl acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, maleic acid amide, maleic acid imide, etc. Be Among these, (meth) acrylic acid, ethyl (meth) acrylate, methyl (meth) acrylate, maleic anhydride and (meth) acrylamide are preferable.
An acrylic monomer may be used individually by 1 type, and may be used combining 2 or more types.

The content of the structural unit derived from the (meth) acrylic acid ester having the structure represented by the above formula (1) is preferably 15 to 25 mol% with respect to all the structural units constituting the (meth) acrylic resin .
The content of the structural unit derived from (meth) acrylic acid is preferably 5 to 10 mol% with respect to all the structural units constituting the (meth) acrylic resin.

  An epoxy compound, an isocyanate compound, etc. are mentioned as a curing agent.

The antistatic agent may contain a solvent. Examples of the solvent include water, alcohol-based organic solvents such as ethanol and isopropyl alcohol, and ester-based organic solvents such as ethyl acetate.
The antistatic agent is obtained by mixing the solution A containing a resin and the solution B containing a curing agent. The cured product of the antistatic agent can be obtained by mixing the solution A and the solution B, and leaving the mixture at 35 to 40 ° C. for 24 to 48 hours.

The thickness _{T 2} of the antistatic layer is appropriately determined in accordance with the determined strength or the like, for example, preferably 0.5 to 5 [mu] m, 1 to 4 [mu] m is more preferable. When the thickness of the antistatic layer is within the above-mentioned numerical range, the glass sheet is excellent in bending strength, and the handleability is improved.

<Thermoplastic resin non-foamed layer>
The thermoplastic resin non-foamed layer (hereinafter, also simply referred to as "non-foamed layer") contains a thermoplastic resin.
As a thermoplastic resin, the thing similar to what was described by said <thermoplastic resin foam layer> is mentioned.

The thickness _{T 3} of the non-foamed layer is suitably determined in accordance with the determined strength or the like, for example, 10 to 50 [mu] m is preferable, 15 to 45 m is more preferable. If it is more than the said lower limit, sufficient intensity | strength will be easy to be acquired. If it is the said upper limit or less, a shaping | molding process is easy and it can have an antistatic function, without impairing the antistatic performance by an antistatic layer.

The non-foamed layer may contain an additive. Examples of the additive include other resins, flame retardants, flame retardant aids, lubricants, spreading agents, coloring agents and the like.
As other resin, the thing similar to what was described by said <thermoplastic resin foam layer> is mentioned.
When the additive is contained in the non-foamed layer, the content is preferably more than 0 parts by mass and not more than 30 parts by mass with respect to 100 parts by mass of the resin.

The center line average roughness in the MD direction measured according to JIS B0601 (1982) on the non-foamed layer side of the interleaf paper for glass plate is 10 μm or more, preferably 10 to 30 μm, more preferably 10 to 25 μm. preferable.
It becomes easy to prevent that a glass plate is contaminated as center-line average roughness of MD direction is in the said numerical range.
The center line average roughness in the TD direction measured according to JIS B0601 (1982) on the non-foamed layer side of the interleaf paper for glass plate is 10 μm or more, preferably 10 to 30 μm, more preferably 10 to 25 μm. preferable.
When the center line average roughness in the TD direction is within the above-mentioned numerical range, it becomes easy to prevent the glass plate from being contaminated.

The 10% compressive strength determined by JIS K6767 of the interleaf paper for glass plates is preferably 0.1 to 0.5 MP, and more preferably 0.15 to 0.45 MPa. If the 10% compressive strength is within the above range, appropriate cushioning can be secured during glass substrate transport.
0.2-0.8MP is preferable and, as for 50% compressive strength calculated | required by JISK6767 of the paper for glass plates, 0.25-0.7MPa is more preferable. When the 50% compressive strength is within the above range, appropriate cushioning properties can be secured when the glass substrates are stacked.

  The thickness T of the interleaf sheet 1 for glass plate is appropriately determined in consideration of applications and the like, and is preferably 0.5 to 1.5 mm, and more preferably 0.6 to 1.2 mm. If it is more than the said lower limit, sufficient intensity | strength will be easy to be acquired. If it is below the said upper limit, molding processing is easy.

The apparent density of the slip sheet glass plate is preferably ^{0.1~0.4g / cm 3, 0.15~0.35g / cm} 3 is more preferable.
If an apparent density is more than the said lower limit, a buffer effect can be improved. If it is below the said upper limit, handleability can be improved more by weight reduction of the paper for glass plates.

100-300 g / m < ² > is preferable and, as for the basic weight of the paper for glass plates, 130-200 g / m < ² > is more preferable.
If a basis weight is more than the said lower limit, a buffer effect can be improved. If it is below the said upper limit, handleability can be improved more by weight reduction of the paper for glass plates.

<Method of manufacturing interleaf paper for glass plate>
An example of the manufacturing method of the interleaf 1 for glass plates is demonstrated.
The method for producing the interleaf paper 1 for glass plate includes, for example, a foamed sheet forming step of obtaining a foamed sheet for forming a thermoplastic resin foam layer, and a non-foamed sheet forming step for obtaining a non-foamed sheet for forming a thermoplastic resin non-foamed layer. It is preferable to provide an antistatic agent application step of applying the antistatic agent to the non-foamed sheet, and a laminating step of laminating the non-foamed sheet coated with the antistatic agent and the foamed sheet.

  The foam sheet forming step is the same as the method for producing the foam sheet described above.

  The non-foamed sheet forming step can adopt a conventionally known non-foamed sheet manufacturing method, and examples thereof include an inflation molding method, an extrusion molding method, and the like.

A conventionally known coating method can be employed for the antistatic agent application step. For example, a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, comma coater, direct coater and the like can be mentioned.
It may have the process of laminating an adhesive ink layer etc. after the antistatic agent application process, and the process of laminating with a non-foamed sheet via an adhesive.

  The laminating step is a step of laminating the foamed sheet on the side of the non-foamed sheet coated with the antistatic agent, to which the antistatic agent is applied. As a lamination method, a conventionally known lamination method can be adopted, and examples thereof include a thermal lamination method and an extrusion lamination method. Thereby, the non-foamed sheet can be adhered to the foamed sheet via the antistatic layer.

Furthermore, the surface of the laminate obtained in the laminating step may have a concavo-convex forming step of transferring the concavo-convex pattern of the press plate.
After the laminate is heated to any temperature in the heater, both sides are pressed with a pressing plate of any temperature. At this time, the uneven pattern on the press surface is transferred to the surface of the non-foamed sheet. The uneven pattern to be transferred can be arbitrarily changed by changing the shape of the press plate to be used.
Next, the obtained glass sheet paper is cut into arbitrary dimensions by a cutting machine.

(Other embodiments)
In the above embodiment, the antistatic layer and the non-foamed layer are provided on one side of the foam layer, but the present invention is not limited to this, and the antistatic layer and the non-foamed layer may be provided on both sides of the foam layer. It may be a layered structure.
Moreover, although the non-foamed layer is located in the surface in the above-mentioned embodiment, you may have another layer (for example, the layer containing a thermosetting resin etc.) on a non-foamed layer.

  Hereinafter, the present invention will be more specifically described by way of Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1
The foam sheet of this example was molded using the same foam sheet manufacturing apparatus as in FIG.
50 parts by mass of a polystyrene resin (product name: XC-515 manufactured by DIC), 50 parts by mass of a polystyrene resin (product name: G9305 manufactured by PS Japan), and a nucleating agent (product name manufactured by Toyo Styrene Co., Ltd.) : 1 part by mass of DSM 1401A) was charged into a first extruded portion (diameter φ 115 mm), heated at 250 ° C., and melt-kneaded to obtain a resin melt.
A foaming agent (a mixture of isobutane: normal butane = 70: 30 (mass ratio)) was supplied to the first extrusion section, and the resin melt and the foaming agent were mixed to form a mixture. The compounding amount of the foaming agent was 2 parts by mass with respect to 100 parts by mass of the resin.
The mixture is fed from the first extrusion section to the second extrusion section (diameter 180 mm), cooled to 165 ° C., extruded using a circular die and foamed, and a cylindrical foam sheet is drawn at a take-up speed of 23 m / min. Obtained. The obtained cylindrical foam sheet was cut along the extrusion direction to obtain a foam sheet having an apparent density of 0.22 g / cm ³ and a thickness of 0.60 mm.
Next, a non-foamed sheet obtained by applying an antistatic agent (Konishi Co., Ltd., product name BONDEIP-PA100) to a biaxially stretched polystyrene film (manufactured by Asahi Kasei Chemicals, product name: OPS GM 25 μm) is antistatically applied to the foam sheet. It was laminated on one side of the foam sheet so that the agent coated surface was on the foam sheet side, and this was heat-sealed with a heat laminator to obtain a laminate.
The resulting laminate is heated with a heater so that the thickness of the laminate is approximately doubled, and then pressed with a press so that the width (a direction perpendicular to the advancing direction of the paper in the paper manufacturing apparatus for paper is taken Orientation) A 1040 mm glass sheet paper was obtained. The center line average roughness of the concavo-convex pattern formed on the surface of the press plate of the press used was 10.4 μm in the MD direction and 11.7 μm in the TD direction.

Example 2
A paper for glass plate was obtained in the same manner as in Example 1, except that the center line average roughness of the concavo-convex pattern formed on the surface of the press plate of the press was 21 μm in the MD direction and 19.4 μm in the TD direction.

[Examples 3 to 5]
A paper for glass plate was obtained in the same manner as in Example 1 except that the apparent density and basis weight of the foam sheet were changed as shown in the table.

Comparative Example 1
High-impact polystyrene-based resin (made by PS Japan Co., Ltd., product name: RH455, containing 20% by mass of Pellestat NC6321 (manufactured by Sanyo Chemical Industries)) 75 parts by mass of non-foamed sheet A paper for paper for glass plate was obtained in the same manner as in Example 1 except that 25 parts by mass of impact polystyrene resin (product name: 475D) was mixed and changed into a film shape. The

Comparative Example 2
A laminated paper for glass plate was obtained in the same manner as in Example 1 except that the antistatic agent coated surface of the thermoplastic resin non-foamed layer was laminated so as to come to the surface and heat sealed with a thermal laminating machine.

Comparative Example 3
A laminated paper for glass plate is obtained in the same manner as in Example 1 except that the center line average roughness of the concavo-convex pattern formed on the surface of the press plate of the press machine is 5.1 μm in the MD direction and 6.4 μm in the TD direction. The

  The apparent density, basis weight, thickness, center line average roughness, compressive strength and fouling resistance of the obtained foam sheet and glass sheet interleaf paper were evaluated, and the results are shown in Table 1.

<Measurement method of thickness>
Except for 20 mm at both ends in the width direction of the foam sheet or the interleaf sheet for glass plate, 21 points were taken as measurement points at intervals of 50 mm in the width direction. About this measurement point, thickness was measured to 0.01 mm of minimum units using dial thickness gauge SM-112 (made by Techlock Co., Ltd.). The average value of the measured values was taken as the thickness T (mm).

<Method of measuring basis weight>
Ten pieces of 10 cm × 10 cm were cut at equal intervals in the width direction except for both ends 20 mm in the width direction of the foam sheet or the interleaf sheet for glass plate, and the mass (g) of each section was measured to 0.001 g. A value of the average value was converted into mass per 1 m ² of the mass (g) of each section, and a basis weight M (g / m ^2).

<Apparent density>
From the thickness T and the basis weight M, the apparent density 厚 み (g / cm ³ ) was determined by the following equation (2).
ρ = M / (T × 10 ³ ) (2)

<Center line average roughness in the MD direction>
According to JIS B0601 (1982), the centerline average roughness of the surface on the non-foamed layer side was measured according to the following procedure using a surface roughness measuring machine.
A surface roughness measuring machine (SJ-201) manufactured by Mitutoyo Corp. is used as a test piece by cutting out 20 sheets in width (TD direction) and 100 mm in length (MD direction) from arbitrary three places of the paper of each example. The center line average roughness of a plane including the center of gravity of each test piece (a plane including positions of 50 mm from both short sides and 10 mm from both long sides) was measured using each test piece, and the average value was determined.
The measurement conditions of centerline average roughness (Ra) are as follows.
When Ra ≦ 12.5 μm, cutoff value: 0.8 mm, measurement length: 2.4 mm or more.
Cut-off value: 2.5 mm, measurement length: 7.5 mm in the case of 12.5 μm <Ra ≦ 100 μm.

<Center line average roughness in the TD direction>
According to JIS B0601 (1982), the centerline average roughness of the surface on the non-foamed layer side was measured according to the following procedure using a surface roughness measuring machine.
A surface roughness measuring machine (SJ-201) manufactured by Mitutoyo Co., Ltd. is used as a test piece by cutting out 20 sheets in any width (MD direction) and 100 mm in length (TD direction) from the three interleaf sheets of each example. The center line average roughness of a plane including the center of gravity of each test piece (a plane including positions of 50 mm from both short sides and 10 mm from both long sides) was measured using each test piece, and the average value was determined.
The measurement conditions of centerline average roughness (Ra) are as follows.
When Ra ≦ 12.5 μm, cutoff value: 0.8 mm, measurement length: 2.4 mm or more.
Cut-off value: 2.5 mm, measurement length: 7.5 mm in the case of 12.5 μm <Ra ≦ 100 μm.

<Compression strength>
Using a Tensilon Universal Testing Machine (manufactured by A & D Co., Ltd., Model: RTG-1301) and attached universal testing machine data processing software, the value measured by the following method is 10% compression stress of the glass sheet, 50 % Compression stress.
The test piece size was 50 × 50 × 50 mm thick, and the test pieces were stacked to a thickness of about 2 mm.
The width and length of the test piece are measured to 1/100 mm using a digital caliper (product name: Digimatic Caliper, model: CD-15, manufactured by Mitutoyo Co., Ltd.), and the thickness of the test piece is a Tentilon universal testing machine The test piece is compressed using (A & D Co., Ltd., model: RTG-1301, load cell: 5 kN, model: UR-5KN-D), and the upper and lower compression plates have a load of 15 N / 25 cm ^2. It measured to 100 mm and was taken as the test start point.
The starting point of displacement was a test start point, the compression rate was 1 mm / min, the stress at 10% compression at the initial thickness was 10% compression stress, and 50% compression stress was 50% compression stress. Three test pieces were measured, and the average of the compressive stress calculated by following Formula was made into 25% compressive stress (kPa) of the paper for glass plates.
σ = (F / A0) × 10 ³
σ: compressive stress (kPa)
F: Load at deformation (N)
A0: Initial cross-sectional area of test piece (mm ² )
The test pieces are conditioned under the conditions of JIS K 7100: 1999 symbol “23/50” (temperature 23 ° C., relative humidity 50%) and a second grade standard atmosphere for 16 hours or more, and then under the same standard atmosphere It measured.

<Method for evaluating the contamination prevention of glass plate surface>
One glass plate (7.5 cm × 2.5 cm) for liquid crystal glass was prepared, and was sandwiched between two sheets of paper for glass plate (8.5 cm × 3.5 cm) to be stacked and placed flat. At this time, by arranging the glass plate and the interleaf for glass plate so as not to protrude from the four sides of the glass plate from the interleaf for glass plate, the contact surface of the glass plate with the interleaf for glass plate is for glass plate It was completely covered by the interleaf. In addition, the paper for glass plates was arrange | positioned so that the non-foamed layer side (in the comparative example 2, antistatic layer side) may contact | connect a glass plate. The resulting laminate was left under an environment of a temperature of 23 ° C. and a humidity of 50% for 4 days while being applied a load of 4 kg / cm ² from above using a pressing jig.
Next, using an optical microscope, the number of foreign substances having a size of 1 μm or more attached to the surface of the glass plate was measured, and the contamination prevention property of the surface of the glass plate was determined according to the determination criteria shown below.
[Criteria for preventing pollution]
◎: not contaminated (the number of foreign particles (particles) adhering to the surface of the glass is 2 pieces / cm ² or less)
○: Partially contaminated but there is no problem in practical use (the number of foreign particles (particles) deposited on the glass surface is 3 to 6 / cm ² )
X: Contaminated (the number of foreign particles (particles) adhering to the surface of the glass is 7 pieces / cm ² or more) or fogging such as oil film is observed on the surface of the glass plate)

In Examples 1 to 5 to which the present invention is applied, the contamination resistance is excellent.
Comparative Example 1 in which the center line average roughness in the MD direction is less than 10 μm was inferior in antifouling properties.
Comparative Example 2 in which the antistatic layer was not located between the foamed layer and the non-foamed layer was inferior in the antifouling property.
Comparative Example 3 in which the center line average roughness in the MD direction is less than 10 μm and the center line average roughness in the TD direction is less than 10 μm was inferior in anti-staining properties.

  DESCRIPTION OF SYMBOLS 1 ... Interleaf paper for glass plates, 10 ... Thermoplastic resin foam layer, 20 ... Antistatic layer, 30 ... Thermoplastic resin non-foam layer

Claims (5)

Having a thermoplastic resin foam layer, an antistatic layer, and a thermoplastic resin non-foam layer in this order,
The center line average roughness in the MD direction measured according to JIS B 0601 (1982) on the surface of the thermoplastic resin non-foamed layer side is 10 μm or more,
The paper for glass plates whose center line average roughness of the TD direction measured according to JIS B0601 (1982) on the surface of the thermoplastic resin non-foamed layer side is 10 μm or more.   The paper for glass plates according to claim 1, wherein the antistatic layer contains a reaction product of a (meth) acrylic resin and a curing agent.   The interleaf paper for glass plates of Claim 1 or 2 whose 10% compressive strength calculated | required by JISK6767 is 0.1-0.5 MPa.   The paper for glass plates according to any one of claims 1 to 3, wherein the 50% compressive strength determined by JIS K6767 is 0.3 to 0.7 MPa.   The paper for glass plates as described in any one of Claims 1-4 whose thickness of the said thermoplastic resin non-foaming layer is 10-50 micrometers.

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