TW201932309A - Sheet material and method for producing sheet material - Google Patents

Abstract

An object of the present invention is to provide a sheet material that can keep a surface of a subject to be protected in a sufficiently clean state after washing with water. Provided is a sheet material including a polyolefin resin foam sheet and a coating film formed on a surface of the polyolefin resin foam sheet, the coating film including an anion surfactant represented by a general formula (1).

Description

Sheet and manufacturing method of sheet

The present invention relates to a sheet and a method for manufacturing the same, and more specifically, to a sheet material (Note: In this case, a sheet material refers to a sheet-like member such as a glass plate, a plastic plate, a metal plate, or a wooden board, which is laminated. Sheets inserted between these components during storage, and not necessarily made of paper) Sheets used and methods of making them.

The polyolefin resin foamed sheet is softer and has better cushioning properties than a polystyrene resin foamed sheet or a polyester resin foamed sheet.

Therefore, polyolefin-based resin foamed sheets are widely used as sheets for packaging electronic parts or home appliances, or as sheets for protecting glass plates.

In particular, when storing members such as glass plates, plate conductor substrates, and metal plates that are substrates for flat display panels, polyolefin resin foamed sheets are widely used as the interleaving paper between the members.

If the polyolefin-based resin foam sheet used as such a backing paper generates static electricity between objects to be protected such as glass plates, foreign matter such as dust may adhere to the surface of the objects to be protected.

Therefore, antistatic properties are expected for polyolefin resin foamed sheet systems.

As a method for causing the polyolefin resin foamed sheet to exhibit antistatic properties, a method is known in which a material for forming a polyolefin resin foamed sheet contains a polymer type antistatic agent called a polymer type antistatic agent.

In addition, as a method for causing the polyolefin resin foamed sheet to exhibit antistatic properties, a method is also known in which a material for forming the polyolefin resin foamed sheet contains a surfactant called a low molecular antistatic agent.

Among them, the surfactant is used as an antistatic agent because it easily leaks out to the surface of the sheet.

On the other hand, when a surfactant is used as the antistatic agent, the surfactant is liable to adhere to the surface of the object to be protected.

Therefore, the surfactant is expected to be easily removed by washing with water or the like even if the surfactant is adhered to the surface of a glass plate or the like.

As described above, for example, in Patent Document 1 described below, a laminated foam sheet using a packaging material for a glass plate for a display is described. The foamed sheet is formed of a polyolefin resin layer on a surface layer portion with a resin composition. The resin composition contains a polyalkylene oxide-based surfactant that can be removed by washing with water even if it is adhered to the surface of a protection object.

[Prior technical literature] [Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2010-42556

In a method for exuding a water-removable surfactant to the surface of a polyolefin resin foamed sheet, the exuded surfactant will adhere to the surface of a glass plate or the like, and the adhered surfactant will have a barrier layer that can be removed by washing. Functions.

That is, the surfactant has a function of effectively forming a barrier layer that prevents foreign matter such as dust from directly attaching to a glass plate.

The dust adhered to the surface of the barrier layer can be easily removed from the surface of the glass plate together with the barrier layer by washing the glass plate.

However, in such a sheet, it may be difficult to make the surface of the protection target after washing with water sufficiently clean.

For example, in recent years, with the diversification of panel sizes, there have been more opportunities to store glass plates for displays for three months or more in a packed state.

Therefore, even when the laminated foamed sheet described in Patent Document 1 is used as a backing paper, it is difficult to make the glass surface sufficiently clean.

Accordingly, it is an object of the present invention to provide a sheet that can sufficiently clean the surface of a protected object after washing, and improve the cleanliness of the protected object even when the protected object is stored for a long time. Sheet.

In order to solve the above-mentioned problems, the present invention provides a sheet, which is a sheet used as a backing paper, which comprises a polyolefin resin foamed sheet and a coating film formed on the surface of the polyolefin resin foamed sheet, and is applied to the aforementioned coating. The film contains an anionic surfactant represented by the following general formula (1).

RO- (CH ₂ -CH ₂ -O) _n -X ... (1)

Here, in the general formula (1), "R-" is a monovalent organic group represented by the following general formula (2), "n" is an integer of 1 to 150, and "-X" is an anionic function base.

H _{2m + 1} C _m -... (2)

Here, "m" in the general formula (2) is an integer of 1 to 14.

In addition, the present invention also provides a method for manufacturing a sheet, which is a method for manufacturing a sheet used as a backing paper. The method is performed on a polyolefin resin foamed sheet by applying a coating material containing the following formula (1) The step of applying a coating solution of an anionic surfactant to produce the sheet having a coating film formed on the surface of the polyolefin resin foamed sheet with the coating liquid.

RO- (CH ₂ -CH ₂ -O) _n -X ... (1)

Here, in the general formula (1), "R-" is a monovalent organic group represented by the following general formula (2), "n" is an integer of 1 to 150, and "-X" is an anionic function base.

H _{2m + 1} C _m -... (2)

Here, "m" in the general formula (2) is an integer of 1 to 14.

Surfactants usually have only thousands of grades even with high molecular weights, and molecular weights are generally hundreds of grades. Therefore, when low molecular weights such as oligomers present in polyolefin resin foamed sheets are exuded, they are accompanied by Risk of exudation.

However, although the surfactant itself can be easily removed by washing with water or the like, there are also substances which cannot be easily removed by washing with water accompanying the exudation.

Therefore, if a barrier layer is formed on the surface of the polyolefin-based resin foamed sheet by the exuded surfactant, a low-molecular-weight compound other than the surfactant may be mixed in the barrier layer.

In the present invention, since a barrier layer can be formed on the surface of an object to be protected by a coating film containing a surfactant, the oligomers existing in the polyolefin resin foamed sheet can be prevented from being mixed into the barrier layer.

That is, according to the present invention, it is possible to provide a sheet in which the surface of the protection target after washing is sufficiently cleaned.

1‧‧‧ sheet

2‧‧‧ glass plate

10‧‧‧Polyolefin resin foam sheet

10’‧‧‧ foam

11‧‧‧The first coating film

12‧‧‧Second coating film

100‧‧‧Laminated body

BE‧‧‧Inlet

CD‧‧‧ Round Die

CT‧‧‧Cutter

DS‧‧‧Die slit

E1‧‧‧The first extrusion machine

E2‧‧‧Second Extrusion Machine

Ex‧‧‧ Tandem Extruder

HP‧‧‧ Feed Hopper

MD‧‧‧ Cooling Mandrel

PL‧‧‧coating solution

WR‧‧‧ Winding roller

SP‧‧‧ Coating device

IV-IV‧‧‧Arrow line

FIG. 1 is a schematic view showing a usage state of one of the known sheets of the present invention.

Fig. 2 is a schematic cross-sectional view of a sheet according to an embodiment of the present invention.

FIG. 3 is a device configuration diagram showing the same state of the equipment for manufacturing a polyolefin resin foamed sheet.

Fig. 4 is a cross-sectional view taken along the line IV-IV of Fig. 3 showing a case where the cylindrical foam extruded by a circular die is cooled by a cooling mandrel.

The sheet of the present invention will be described below.

In the following examples, the case where the base material of the sheet is a polyolefin-based resin foamed sheet, and the polyolefin-based resin foamed sheet is an extruded foam.

Specifically, the following describes a case where a sheet is used as a backing paper for a glass plate, and the embodiment of the present invention is described below. The sheet is provided with a polyolefin resin foamed sheet as a substrate, and the polyolefin The resin foamed sheet is formed into a sheet shape by extrusion-foaming a polyolefin-based resin composition containing a polyolefin-based resin.

The sheet 1 of this embodiment shown in FIG. 1 is used as a user of a stabilizer placed between the glass plates 2 when a plurality of glass plates 2 are laminated in the vertical direction to form a laminated body 100.

The aforementioned glass plate 2 in this embodiment is a glass plate for a flat display panel such as a plasma display panel or a liquid crystal display panel.

The sheet 1 according to this embodiment includes a polyolefin-based resin foamed sheet 10 as a base of the sheet 1 shown in FIG. 2 and a coating film formed on the polyolefin-based resin foamed sheet.

The sheet 1 of this embodiment includes a first coating film 11 laminated on a first surface of a polyolefin resin foamed sheet 10 and a second coating film 12 laminated on a second surface opposite to the first surface. .

In other words, the sheet 1 of this embodiment forms a coating film on both surfaces of the polyolefin resin foamed sheet 10, and includes a first coating film 11 / polyolefin resin foamed sheet 10 / second coating film. Three-layer construction of 12.

Examples of the polyolefin-based resin contained in the polyolefin-based resin foamed sheet 10 of this embodiment include polyethylene-based resins, polypropylene-based resins, and ethylene-α-olefin resins.

The polyolefin-based resin composition constituting the polyolefin-based resin foamed sheet does not need to contain only one kind of polyolefin-based resin alone, and may contain two or more kinds.

The polyolefin-based resin contained in the polyolefin-based resin composition is preferably a low-density polyethylene resin.

The aforementioned low-density polyethylene resin may be, for example, a linear low-density polyethylene resin (LLDPE) polymerized by a low-pressure method, or a low-density polyethylene resin (LDPE) that forms a long-chain branch in a molecular structure by a high-pressure method.

The aforementioned low-density polyethylene resin is preferably a low-density polyethylene having a melt mass flow rate (hereinafter also referred to as "MFR") of 2 to 6 g / 10 min, a resin density of 925 kg / m ³ or more, and 935 kg / m ³ or less. Resin (LDPE).

The reason why the low density polyethylene resin (LDPE) of the MFR as described above is preferable is that when the MFR is less than 2g / 10min, the kneading performance with the polymer-type antistatic agent described below is equal to that in the extruder, During extrusion foaming, foam breakage or the like may occur, and it may be difficult to obtain a good polyolefin resin foamed sheet.

The reason why the above-mentioned MFR low-density polyethylene resin (LDPE) is preferable is that if the MFR exceeds 6g / 10min, the melt tension becomes too low, and it is difficult to obtain a low-density polyolefin resin foamed sheet. Eye-waste deposits are easily generated at the tip of the mold.

The above-mentioned melt mass flow rate, in this specification, unless otherwise specified, the MFR of the polymer-type antistatic agent described below refers to the melt mass flow rate (MFR) of plastics-thermoplastics in accordance with JIS K 7210: 1999. ) And Melt Volume Flow Rate (MVR) Test Method "The value measured by the method described in Method B (where the test temperature is 190 ° C and the load is 21.18 N).

The reason why the aforementioned polyethylene-based resin contained in the polyolefin-based resin foamed sheet 10 according to this embodiment preferably has the above-mentioned density is that when the resin density is less than 925 kg / m ³ , the foamed sheet is derived from the extruded foamed sheet. The foaming agent dissipates quickly, and the resin itself has a small rigidity, and there is a possibility that the shrinkage cannot be suppressed. On the other hand, if the resin density exceeds a value of 935 kg / m ³ , the rigidity of the resin itself is too large, and the sheet may not Shows the possibility of good cushioning.

The polyolefin-based resin composition constituting the polyolefin-based resin foamed sheet 10 may optionally contain a polymer-type antistatic agent.

Examples of the polymer-type antistatic agent include ionic polymers such as polyethylene oxide, polypropylene oxide, polyethylene glycol, polyester ammonium amine, polyether ester ammonium amine, and ethylene-methacrylic acid copolymer. Quaternary ammonium salts such as polyethylene glycol methacrylate copolymers, and the copolymers of olefin-based blocks and hydrophilic blocks described in Japanese Patent Application Laid-Open No. 2001-278985.

Among these, a copolymer of an olefin block and a hydrophilic block is preferred, and a polyether-polyolefin block copolymer (block copolymerization of a polyether block and a polyolefin block) is more preferred.物).

In addition, the polymer antistatic agent may be a mixture of two or more substances. In order to further improve the antistatic performance, it may be a mixture of polyamine with the above-mentioned block copolymer, or a polyamine based block. Co-aggregators.

The polymer-type antistatic agent is more preferably a polyether-based block and a copolymer containing an olefin-based block containing 70 mol% or more of propylene as a main component.

In the polymer-type antistatic agent, the proportion of the polyether-polyolefin block copolymer is preferably 70% by mass or more, and more preferably 80% by mass or more.

The polymer type antistatic agent constituting the foamed sheet together with the polyolefin resin is preferably a polymer type having a crystallization temperature of 10 to 90 ° C, a melting point of 100 to 130 ° C, and an MFR of 20 to 40g / 10min. Antistatic agent.

The reason why the polymerized antistatic agent has a crystallization temperature of 90 ° C or lower is that, if the crystallization temperature exceeds 90 ° C, crystallization in the extruded preparation proceeds and the dispersion becomes worse. During foaming, when the bubble film is extended, the polymeric antistatic agent will not deform and become agglomerated, and the distance between the dispersed particles of the antistatic agent will increase, making it difficult to exhibit the antistatic function in accordance with the amount added.

The reason why the MFR of the polymer-type antistatic agent is preferably within the aforementioned range is that when the MFR of the polymer-type antistatic agent is less than 20 g / 10min, the polyolefin resin is extruded in an extruder or a mold. The dispersion is uneven, and the static decay rate tends to be deteriorated.

The reason why MFR is preferably within the above range is that when a polymer-type antistatic agent having an MFR of more than 40 g / 10min is used, the dispersibility in the polyolefin resin is reduced, and the melt tension of the polyolefin resin composition is reduced. It reduces the possibility that a low-density foamed sheet cannot be obtained, or that a plurality of air bubbles communicate with each other to become a large air bubble.

In addition, in the present specification, the crystallization temperature refers to a value measured according to a method described in JIS K122 "Method for Measuring the Transition Temperature of Plastics" unless otherwise specified.

Specifically, a differential scanning thermal analyzer (for example, "DSC6220" manufactured by SII Technology) can be used to fill a measuring container with about 6.5 mg of sample, and cool at a temperature of 10 ° C / min under a nitrogen flow of 30ml / min. The temperature was raised and cooled between 30 ° C and 200 ° C, and the exothermic peak temperature during cooling was measured as the crystallization temperature.

When there are two or more exothermic peaks, the temperature of the peak of the peak measured at the highest temperature is used as the crystallization temperature in the area peaks having 5% or more of the total peak area.

When the polyolefin-based resin composition contains the polymer-type antistatic agent, when the total amount of the polyolefin-based resin contained in the polymer-type resin composition is 100 parts by mass, it is preferably 2 The polyolefin resin composition is contained in a proportion of at least 15 parts by mass.

Since the polyolefin-based resin foamed sheet 10 of this embodiment is manufactured by an extrusion foaming method, in addition to the components described above, it may further contain components that are more important for foaming.

Examples of the component for foaming include a foaming agent and a bubble regulator.

Examples of the blowing agent include hydrocarbons such as isobutane, n-butane, propane, pentane, hexane, cyclobutane, and cyclopentane; and inorganic gases such as carbon dioxide and nitrogen.

Among them, the aforementioned blowing agent is preferably a mixed butane of isobutane and n-butane.

If such a mixture of isobutane and n-butane is used, the rapid escape of the foaming agent in the extrusion step can be suppressed by isobutane.

On the other hand, n-butane, which has excellent compatibility with polyolefin resins, can suppress an increase in the continuous cell ratio.

When such a mixed butane is used, a polyolefin-based resin foamed sheet 10 having small shrinkage and excellent cushioning properties with low continuous cell ratio can be obtained.

In addition, although the amount of the foaming agent used in the extrusion foaming depends on the desired degree of foaming, it is relative to 100 parts by mass of the total of the polyolefin resin and the polymer antistatic agent. It is usually 5 parts by mass or more and 25 parts by mass or less.

Generally, the reason why the addition ratio of the foaming agent is in such a range is that if the foaming agent is less than 5 parts by mass, it is difficult to obtain sufficient foaming, and if it exceeds 25 parts by mass, the bubble film is broken and it is difficult There is a fear of obtaining a good polyolefin resin foamed sheet.

In addition, the aforementioned bubble adjusting agent for adjusting the bubbles formed by the blowing agent may be, for example, inorganic powder such as talc, silica, or a polycarboxylic acid that can also be used as a decomposition type blowing agent, and sodium carbonate. Or a mixture of sodium bicarbonate (sodium bicarbonate), azomethoxamine, and the like.

These may be used alone or in combination. The added amount of the bubble regulator is preferably such that the polyolefin-based resin is 0.5 parts by mass or less per 100 parts by mass.

In addition to the above-mentioned components, the polyolefin-based resin foamed sheet 10 in this embodiment may need to contain additives such as a heat stabilizer, an ultraviolet absorber, an antioxidant, and a colorant.

The ratio of the polyolefin-based resin to the components contained in the polyolefin-based resin foamed sheet 10 other than the polymer-type antistatic agent is preferably 10% by mass or less, and more preferably 5 parts by mass or less.

That is, in the polyolefin-based resin composition constituting the polyolefin-based resin foamed sheet 10, the total ratio of the polyolefin-based resin and the polymer antistatic agent is preferably 90% by mass or more, and more preferably 95% by mass or more. .

The content of other components is preferably 10% by mass or less, and more preferably 5 parts by mass or less. The same applies when the polyolefin-based resin foamed sheet 10 does not contain a polymer-type antistatic agent of any component. .

The density (appearance density) of the polyolefin-based resin foamed sheet 10 constituted by such a polyolefin-based resin composition is not particularly limited as long as it can exhibit a generally required cushioning property as a glass plate liner, etc. Yes, it is usually less than 70 kg / m ³ , preferably 10 kg / m ³ or more and 60 kg / m ³ or less.

The reason for selecting such a density is that when the density is 70 kg / m ³ or more, the flexibility of the polyolefin-based resin foamed sheet 10 is insufficient and the cushioning property may be low. If the density is too small, the polyolefin-based resin may have a low density. The strength of the foamed sheet 10 may be insufficient, and as a result, there may be a case where the cushioning property is low.

Furthermore, if the thickness of the bubble film becomes too thin, the shrinkage becomes large. As a result, when the long polyolefin-based resin foamed sheet 10 is produced, it is difficult to wind it into a roll.

Therefore, the density of the polyolefin-based resin foamed sheet 10 is preferably 10 kg / m ³ or more, and more preferably 15 kg / m ³ or more.

The sheet material of this embodiment has coating films 11 and 12 containing an anionic surfactant on both sides of the polyolefin resin foamed sheet 10 as described above.

The types and contents of the anionic surfactants contained in the first coating film 11 and the second coating film 12 of the polyolefin resin foamed sheet 10 may be the same or different.

When the sheet is used as a backing sheet for a glass plate, from the viewpoint that both the front surface and the back surface can be used, the type and content of the anionic surfactant of the first coating film 11 are preferably the same as those of the second coating film 12.

The first coating film 11 and the second coating film 12 may contain components other than the anionic surfactant, but each of the first coating film 11 and the second coating film 12 preferably contains an anionic surfactant in a proportion of 90% by mass or more.

The content of the anionic surfactant in the first coating film 11 or the second coating film 12 is more preferably 95% by mass or more, and particularly preferably 98% by mass or more.

The first coating film 11 and the second coating film 12 are particularly preferably composed of substantially only an anionic surfactant.

In the first coating film 11 and the second coating film 12, the anionic surfactant includes a polyoxyethylene alkyl ether structure as the aforementioned anionic surfactant in order to make the surface of the glass plate 2 washed with water clean. An anionic surfactant having an anionic functional group at the end of the ethylene structure (hereinafter, also referred to as "polyoxyethylene alkyl ether type anionic surfactant").

In addition, in the first coating film 11 and the second coating film 12, as the polyoxyethylene alkyl ether type anionic surfactant as described above, the polyoxyethylene alkyl group having a carbon number of 14 or less in the alkyl chain is included. Ether type anionic surfactant.

Specifically, the first coating film 11 and the second coating film 12 include an anionic surfactant represented by the following general formula (1).

RO- (CH ₂ -CH ₂ -O) _n -X ... (1)

Here, in the general formula (1), "R-" is a monovalent organic group represented by the following general formula (2), "n" is an integer of 1 to 150, and "-X" is an anionic function base.

H _{2m + 1} C _m -... (2)

Here, "m" in the general formula (2) is an integer of 1 to 14.

That is, "R-" in the general formula (1) is a monovalent group in which one hydrogen atom is removed from a linear or branched alkane.

Examples of the anionic functional group "-X" include the following general formulae (a1) to (a4).

(a1) -COO ^- M ⁺

(a2) -SO ₃ ^- M ⁺

(a3) -O-SO ₃ ^- M ⁺

(a4) -O-PO (OH) O ^- M ⁺

Here, "M ⁺ " in the general formulae (a1) to (a4) represents a monovalent cation.

The "m" in the general formula (2) is preferably 6 or more (6 to 14), more preferably 8 or more (8 to 14), and particularly preferably 10 or more (10 to 14).

"M" is more preferably any one of 12 or 13.

The anionic functional group "-X" may be, for example, a sulfate represented by the general formula (a2).

The cation (M ⁺ ) is preferably a metal ion such as a lithium ion, a potassium ion, or a sodium ion, or an ammonium ion.

Among them, the cation (M ⁺ ) is preferably a sodium ion.

That is, the polyoxyethylene alkyl ether anionic surfactant represented by the general formula (1) is particularly preferably any one of polyoxyethylene lauryl ether sodium sulfate or polyoxyethylene tridecyl ether sodium sulfate. .

The first coating film 11 and the second coating film 12 may individually contain one kind of the polyoxyethylene alkyl ether represented by the general formula (1), or may contain two or more kinds.

The first coating film 11 and the second coating film 12 may contain an anionic surfactant other than the polyoxyethylene alkyl ether represented by the general formula (1). The first coating film 11 and the first The anionic surfactant contained in the second coating film 12 is preferably 95% by mass or more of a polyoxyethylene alkyl ether represented by the general formula (1).

The proportion of the polyoxyethylene alkyl ether represented by the general formula (1) in the anionic surfactant contained in the first coating film 11 and the second coating film 12 is particularly preferably 98% by mass or more.

The first coating film 11 and the second coating film 12 are more particularly preferably composed of only the polyoxyethylene alkyl ether represented by the general formula (1).

The anionic surfactant contained in the coating films 11 and 12 migrates to the surface of the glass plate 2 through contact between the glass plate 2 and the sheet 1 belonging to the protection object protected by the surface of the sheet 11. A hydrophilic protective film is formed on the surface of the glass plate 2.

Thereby, the glass plate 2 is protected by the adhesion of foreign matter, and a clean surface state can be obtained after washing with water.

In addition, the state where the glass plate 2 can obtain a clean surface state after being washed with water can be maintained for a long time.

Therefore, the glass plate 2 can be easily cleaned even after the sheet 1 of this embodiment is used as a backing paper in an inserted state for a long period of time for more than 3 months.

In addition, in the present embodiment, the reason why the coating film contains an anionic surfactant having an alkyl group having the above-mentioned chain length is that even if the alkyl group has the same chain length, when the surfactant is a nonionic surfactant, Or even if it is the same anionic surfactant, but when the chain length of the alkyl group is long, the protective film on the surface of the glass plate 2 cannot exhibit sufficient hydrophilicity, and the surface of the glass plate 2 is likely to produce relatively anionic Surfactants are lipophilic deposits that are not easily removed by washing with water.

In this embodiment, as described above, the reason why the anionic surfactant is not exuded from the inside of the polyolefin resin foamed sheet, but is maintained on the surface of the polyolefin resin foamed sheet in the state of a coating film is because When the anionic surfactant is fully exuded, it is possible to suppress the formation of lipophilic deposits on the surface of the glass plate 2 and to suppress the oligomerization of the anionic surfactant from the inside of the polyolefin resin foam sheet with the exudation of the anionic surfactant Low-molecular-weight compounds that are lipophilic.

Therefore, the polyolefin-based resin composition constituting the polyolefin-based resin foamed sheet 10 of this embodiment may contain an anionic surfactant or a non-ionic surfactant if necessary. And other low-molecular-type antistatic agents, but for the reasons described above, it is preferred to limit the low-molecular-type antistatic agent contained in the polyolefin-based resin composition as much as possible.

Specifically, the content of the low-molecular-weight antistatic agent in the polyolefin-based resin composition is preferably 2% by mass or less, more preferably 1% by mass, and particularly preferably not substantially contained.

The content of the polyoxyethylene alkyl ether anionic surfactant per unit area (1 m ² ) of the polyolefin-based resin foamed sheet 10 of the first coating film 11 and the second coating film 12 is preferably, It is 3 mg / m ² or more and 100 mg / m ² or less.

The content of the polyoxyethylene alkyl ether anionic surfactant in each coating film is more preferably 3 mg / m ² or more and 80 mg / m ² or less, and particularly preferably 4 mg / m ² or more and 50 mg / m ² or less. The content of the surfactant per unit area of the coating film can be obtained in the following manner.

(Quantitative of surfactant)

A square sample with a side of about 10 cm was cut from the sheet.

Next, the sample was immersed in 50 ml of distilled water and stored at room temperature of 23 ° C for 40 minutes to dissolve the surfactant.

The obtained eluate was measured by a liquid chromatography tandem mass spectrometer (LC / MS / MS). Based on the calibration curve obtained from the standard solution, the concentration of the surfactant (d (%) in the eluate ).

From the concentration (d (%)) and the amount of distilled water (50 ml) used in the eluate, the mass of the surfactant contained in the eluate (m ₁ (mg) = 50 × d) was obtained.

The eluted sample was immersed in 50 ml of distilled water, and the same measurement was performed to determine the mass (m ₂ (mg)) of the surfactant contained in the eluted solution.

This measurement was repeatedly performed, and the elution of the surfactant was performed below the detection limit, and the total amount of the surfactant (M = m ₁ + m ₂ + ...) attached to the sample piece was determined.

Measure the surface area of the sample as accurately as possible (S: about 200 cm ² (about 100 cm ² × 2 (both sides))), and divide the total amount (M) of the surfactant obtained before by the surface area (S). The interfacial active dose (M / S) per unit area of the coating film can be obtained.

When it is necessary to measure the first coating film 11 and the second coating film 12 separately, the sample can be cut from the central part in the thickness direction to make two horizontal slices, or the single side of the sample can be sufficiently wiped to perform the above measurement. .

The test conditions of LC / MS / MS can be as follows.

(LC / MS / MS test conditions)

． Device used:

Liquid chromatography tandem mass spectrometer (LC / MS / MS) (model "UHLCACCELA" manufactured by Thermo SCIENTIFIC)

． Tubing:

Hypersil GOLD C18 manufactured by Thermo 1.9μm (2.1mm I.D. * 10mmL)

． Measurement conditions:

Column temperature (40 ° C), mobile phase (A: 10mM ammonium acetate / B: acetonitrile = 10/90)

． Method of making calibration curve:

Prepare several tested standard solutions of surfactants at a concentration between 0.01ppm and 10ppm, and perform LC / MS / MS measurement under the same conditions to prepare a calibration curve of the detected peak area and standard solution concentration.

The sheet 1 having the aforementioned coating films 11 and 12 can be produced by applying a coating solution containing the aforementioned anionic surfactant to a polyolefin resin foamed sheet.

That is, the manufacturing method of the sheet 1 of this embodiment is a manufacturing method of a sheet used as a backing paper, and it is a method of coating the polyolefin resin foamed sheet 10 with an anion represented by the general formula (1). It is a step of applying a coating solution of a surfactant, and the sheet 1 having the coating films 11 and 12 formed of the coating solution on the surface of the polyolefin-based resin foamed sheet is produced.

The content per unit area of the aforementioned anionic surfactant contained in the coating films 11 and 12 of the sheet 1 manufactured as described above is preferably within a predetermined range.

More specifically, the step of applying the coating liquid is preferably performed in such a manner that the content of the anionic surfactant in the coating film per unit area is 3 mg / m ² or more and 100 mg / m ² or less. .

The formation of the coating films 11 and 12 as described above can be continuously performed in the production of the polyolefin-based resin foamed sheet 10.

As mentioned above, the polyolefin resin foamed sheet 10 of this embodiment is manufactured by the extrusion foaming method.

Specifically, the polyolefin resin foamed sheet 10 can be produced by continuously extruding and foaming the polyolefin resin composition into a sheet shape from a round die installed at the front end of an extruder to produce the polyolefin resin composition. Extrusion step of extruded foamed sheet; the extruded sheet is wound by a winding roll to produce a sheet roll winding step.

In the production of the polyolefin-based resin foamed sheet 10, for example, the manufacturing equipment shown in Figs. 3 and 4 can be used.

The manufacturing equipment shown in the drawings includes: a tandem extruder Ex, which is two extruders connected to the upstream first extruder E1 and the downstream second extruder E2; a round die CD is installed at the front end of the tandem extruder Ex; cylindrical cooling mandrel MD is a circle ejected from the inside by the circular die slit DS opening in the front of the round die CD. The cylindrical foam body 10 'is used for cooling the foam body 10'; the cutter CT is used to expand the cylindrical foam body 10 'cooled by the cooling mandrel MD to The polyolefin-based resin foamed sheet 10 having a belt shape is formed; and the winding roller WR is a polyolefin-based resin foamed sheet 10 which is formed into a belt shape by the cutter CT, and is wound into a drum on the most downstream side of the equipment. It is on the upstream side of the winding roll WR, and further includes a coating device SP for spray-coating the coating liquid PL on both sides of the polyolefin-based resin foamed sheet 10.

In the above-mentioned extrusion step in this embodiment, the first extruder E1 having a feeding hopper HP and a blowing agent introduction port BE having a raw material input port for polyolefin resin and the like is used to make the polyolefin containing the blowing agent The resin composition is melt-kneaded, and the melt-kneaded material obtained in the first extruder E1 is further kneaded in the second extruder E2 on the downstream side.

Next, the molten polyolefin-based resin composition kneaded in the second extruder E2 is extruded into a circular shape by a circular die slit DS of a circular die CD installed at the front end of the second extruder E2. The cylindrical shape is a cylindrical foam 10 '.

In this extrusion step, the aforementioned foam body 10 'is continuously extruded from the aforementioned round die CD. Immediately after the extrusion, the foam body 10' is blown with cooling air (not shown) from the inside to perform air cooling The primary cooling is performed, and the air-cooled foam is cooled again using a cooling mandrel MD to perform secondary cooling.

In the aforementioned extrusion step, the cylindrical foam 10 'is cut in the extrusion direction by a cutter CT provided on the downstream side of the cooling mandrel MD, and wound by a winding roll WR.

In the aforementioned extrusion step in this embodiment, the secondary cooling is performed using a cooling mandrel MD having a larger outer diameter than the diameter of the die slit DS.

Accordingly, the secondary cooling is performed by sliding the outer peripheral surface of the cooling mandrel MD to the inner peripheral surface of the cylindrical foamed body 10 'after the primary cooling.

In this secondary cooling, while cooling the primary-cooled cylindrical foam 10 ', the diameter is also expanded by the cooling mandrel MD.

As described above, the foam cut by the cutter CT in the extrusion direction is unrolled into a belt shape and then wound by a winding roll WR constituting the raw material film roll.

The coating films 11 and 12 are formed by applying a coating solution PL to the polyolefin-based resin foamed sheet 10 thus prepared.

In the equipment illustrated in the figure, a coating device SP is used to spray the entire coating liquid on both sides of the polyolefin-based resin foamed sheet 10, thereby forming the aforementioned coating films 11 and 12.

The coating films 11 and 12 can be formed by performing the following steps: a coating liquid preparation step to prepare a coating liquid containing the anionic surfactant, and a coating step to apply the coating on both sides of the polyolefin resin foamed sheet 10. liquid.

The coating liquid can be applied in parallel with the extrusion step or after the extrusion step is completed.

That is, the sheet roll produced in the winding step may be a sheet roll with a coating film formed thereon, or a sheet roll made of only a polyolefin resin foam sheet.

In the aforementioned coating solution preparation step, a coating solution containing only an anionic surfactant may be prepared, or a coating solution containing a solvent for adjusting the viscosity of the coating solution together with the anionic surfactant may be prepared.

The aforementioned coating step can be performed by a general method such as roll coating, contact coating, spray coating, and bristle coating.

When the application of the coating liquid and the extrusion step are carried out in parallel, the application of the coating liquid may be performed on the upstream side of the cooling mandrel MD or on the downstream side thereof.

The coating liquid may be applied by spraying the coating liquid inside and outside the extruded cylindrical foam if necessary, or it may be performed together with the primary cooling performed before the secondary cooling by the cooling mandrel MD.

In this case, it is possible to reduce the frictional force generated between the polyolefin resin foamed sheet (cylindrical foam) and the cooling mandrel MD.

Even if it is a polyolefin-based resin foamed sheet after secondary cooling with a cooling mandrel, its surface temperature is generally higher than normal temperature (23 ° C). Therefore, when the coating liquid coating and extrusion steps are carried out in parallel, Where the coating liquid is applied, the coating liquid is applied to a polyolefin resin foamed sheet in a warm state.

In this way, in the film, the anionic surfactant is in a state of easy molecular movement, and the hydrophilic functional groups are easy to be concentrated on the surface, which is beneficial for the glass plate to form a protective film that can be easily washed and removed.

In the coating step, in order to form a coating film on both sides of the polyolefin-based resin foamed sheet, it is not necessary to apply the coating solution to both sides of the polyolefin-based resin foamed sheet.

For example, a method may be adopted in which a coating film is formed only on one side of the polyolefin resin foamed sheet, and when forming a sheet roll, a part of the coating liquid is transferred on the other side where the coating film is not formed.

When the application of the coating liquid is not performed in parallel with the extrusion step, but is performed after the extrusion step is completed, the application of the coating liquid may be performed at the time of rewinding the sheet roll.

Moreover, in this embodiment, the case where the polyolefin resin foamed sheet manufactured by extrusion foaming is used as a stabilizer for a glass plate is illustrated. However, the sheet of the present invention is not limited to its use. The same effect can also be expected when using a liner for a glass plate as a liner for a glass plate, even if members other than the glass plate are intended to be washed with water by using the packaging or the like.

That is, the present invention is not limited in any way by the above examples.

[Example]

Next, the present invention will be described in more detail with examples, but the present invention is not limited to these.

(Example 1)

Relative to 100 parts by mass of a low-density polyethylene resin (trade name: "LF580", density: 931 kg / m ³ , MFR = 4.0g / 10min) made by Japan Polyethylene Co., Ltd. 4 parts by mass of molecular antistatic agent (polyether-polyolefin block copolymer, trade name: "PELECTRON LMP", crystallization temperature: 56 ° C, melting point: 115 ° C, MFR = 30g / min) The company's masterbatch (Masterbatch containing azodicarbamide: brand name "CellmicMB 1023") is a compound with a ratio of 0.15 parts by mass and supplied to the first extruder (cylinder of the tandem extruder). path: 90 mm), melt-kneaded in the extruder so that the maximum temperature reached 210 ° C.

In the middle of this first extruder, mixed butane (isobutane / n-butane = 50/50 (mole ratio)) as a foaming agent was used in an amount of 100 mass relative to the aforementioned low density polyethylene resin. The ratio of 18 parts by mass is squeezed in.

After the melt-kneading of the first extruder, the second extruder (cylinder diameter: 150mm) cooled to a temperature range suitable for foaming (111 ° C), extruded from a round die with an outlet diameter of 222mm (slit 0.04mm) into the atmosphere, and made into a cylindrical polyolefin resin foam Sheet (cylinder foam).

The resin temperature during extrusion was 116 ° C.

The foamed cylindrical foam was extruded, cooled by blowing air, and then cooled along a cooling mandrel having a diameter of 770 mm and a length of 650 mm.

The cylindrical foam was cut in the extrusion direction by a cutter provided on the rear side of the cooling mandrel, thereby obtaining a long-belt-shaped polyolefin-based resin foamed sheet.

A 10% aqueous solution of sodium polyoxyethylene lauryl ether sulfate was prepared as a coating liquid for forming a coating film on the long-belt-shaped polyolefin-based resin foamed sheet.

The coating liquid was sprayed on one side of the polyolefin-based resin foamed sheet (the inner peripheral surface side in the state of the cylindrical foam) with a sprayer to prepare a coating film.

The sheet having the thickness of the coating film was formed into a roll shape at a winding speed of 50 m / min.

The physical properties of the obtained sheet of Example 1 are as shown in the table.

Regarding Example 2 and below, the type and amount of the surfactant to be applied were changed as shown in the table.

The details of the surfactants shown in the table are as follows.

In addition, in Comparative Example 3, a coating film was not formed, and instead, a polyolefin-based resin composition for producing a polyolefin-based resin foamed sheet by an extrusion foaming method was allowed to contain a surfactant.

1) Anionic surfactant 1 (A-SSA1):

Polyoxyethylene lauryl (C12) sodium ether sulfate

2) Anionic surfactant 2 (A-SSA2):

Polyoxyethylene tridecane (C13) sodium ether sulfate

3) Anionic surfactant 3 (A-SSA3):

Polyoxyethylene alkyl (C12-C14) sodium ether sulfate

4) Anionic surfactant 4 (A-SSA4):

Polyoxyethylene alkyl (C16-C18) sodium sulfate

5) Non-ionic surfactant 1 (N-SSA1):

Polyethylene glycol (molecular weight 1500)

6) Non-ionic surfactant 2 (N-SSA2):

Polyoxydecane tridecyl ether

(Quantitative of surfactant)

From the sheets of each of the examples and comparative examples, a square sample having a side length of about 10 cm was cut, and the surface area of the sample (S ≒ 200 cm ² ) was accurately determined.

Next, this sample was immersed in 50 ml of distilled water and stored at a room temperature of 23 ° C for 40 minutes to dissolve the surfactant.

The obtained eluate was measured by a liquid chromatography tandem mass spectrometer (LC / MS / MS), and the concentration (d (%)) of the surfactant in the eluate was calculated based on the calibration curve obtained from the standard solution. .

From the concentration (d (%)) and the amount of distilled water (50 ml) used in the eluate, the mass of the surfactant contained in the eluate (m ₁ (mg) = 50 × d) was obtained.

The eluted sample was immersed in 50 ml of distilled water, and the same measurement was performed to determine the mass (m ₂ (mg)) of the surfactant contained in the eluted solution.

Divide the first dissolution mass (m ₁ ) by the surface area (S) to calculate the “first dissolution amount”, and divide the second dissolution mass (m ₂ ) by the surface area (S) to calculate the “second Secondary Dissolution ".

The test conditions of LC / MS / MS are as follows.

(LC / MS / MS test conditions)

Device used:

Liquid chromatography tandem mass spectrometer (LC / MS / MS) (model "UHLCACCELA" manufactured by Thermo Scientific Corporation)

Tubing:

Hypersil GOLD C18 manufactured by Thermo 1.9μm (2.1mm I.D. * 100mmL)

Measurement conditions:

Column temperature (40 ° C), mobile phase (A: 10mM ammonium acetate / B: acetonitrile = 10/90)

Method of making calibration curve:

Prepare several tested standard solutions of surfactants at a concentration between 0.01ppm and 10ppm, and perform LC / MS / MS measurement under the same conditions to prepare a calibration curve of the detected peak area and standard solution concentration.

(Measurement of contact angle)

When the display glass is stored for a long time in the state of the sheets obtained from the examples and comparative examples, the evaluation of whether or not it has the effect of exhibiting the cleanness of the glass surface is judged by the contact angle after heating in the following cycle .

First, cut a foamed sheet of backing paper into a size of 5 cm × 10 cm, and place it on a washed and dried glass plate (alkali-free glass OA-10G manufactured by Japan Electric Glass Co., Ltd.) to In the manner of applying a load to the entire sheet, a weight of 1 kg was applied, and heating was performed in a constant temperature and humidity tank (manufactured by ISUZU, trade name "HPAV-120-40") in the following cycle.

(Circulation conditions)

The heating of the sheet is performed by using the following (1) to (4) as a cycle.

(1) From 20 ° C. 60% RH was heated to 60 ° C in 1 hour. 90% RH

(2) At 60 ° C. 90% RH for 1 hour

(3) From 60 ° C. 90% RH is reduced to 20 ℃ in 1 hour. 60% RH

(4) At 20 ° C. 90% RH for 1 hour

The sheet was removed from the surface of the glass plate after the above-mentioned cycle heating test, and the glass plate was washed with washing water containing 0.4% household alkaline detergent (manufactured by Kao Corporation, trade name "Attack"). After rinsing with distilled water, it was dried at a temperature of 30 ° C and a relative humidity of 0% for 24 hours.

A solid-liquid interface analyzer (trade name "DROP MASTER 300") manufactured by Kyowa Interface Chemical Co., Ltd. was used to measure the contact angle of the purified water on the surface of the glass plate in contact with the sheet.

The measurement was performed three times after performing cyclic heating for 60 cycles, after performing 120 cycles, and after performing 180 cycles.

The contact angle was measured at 20 points each, and the average value was calculated.

The results are shown in Table 2.

In addition, using the same surfactant as in Example 1, the coating amount of the surfactant to the polyolefin resin foamed sheet was greatly reduced, and the same evaluation as described above was carried out. The results are as follows.

From the above results, it can be seen that when the content of the anionic surfactant in the unit area of the coating film is 1 mg / m ² or less, a sufficiently significant effect cannot be confirmed. Considering the significance of the effect, it is preferable to ensure 3 mg / Content of m ² or less.

It can also be seen from the above that when a sheet of the present invention is used as a protection object, the surface after washing with water can be effectively cleaned.

Claims (4)

A sheet is a sheet used as a stabilizer. The sheet includes a polyolefin resin foamed sheet and a coating film formed on the polyolefin resin foamed sheet. The coating film includes the following An anionic surfactant represented by formula (1); RO- (CH ₂ -CH ₂ -O) _n -X ... (1) Here, in the general formula (1), R- is the following: A monovalent organic group represented by formula (2), n is an integer of 1 to 150, -X is an anionic functional group; H _{2m + 1} C _m -... (2) Here, the general formula (2) Where m is an integer from 1 to 14. The sheet according to item 1 of the scope of patent application, wherein the content of the anionic surfactant in the coating film is 3 mg / m ² or more and 100 mg / m per unit area in the polyolefin resin foamed sheet. ² or less. A method for manufacturing a sheet is a method for manufacturing a sheet used as a backing paper. The method is to apply an anionic interfacial activity to a polyolefin resin foamed sheet containing an anionic system represented by the following general formula (1). Step of a coating solution of an agent, and the aforementioned sheet having a coating film formed from the aforementioned coating solution on the surface of the aforementioned polyolefin resin foamed sheet; RO- (CH ₂ -CH ₂ -O) _n -X .. (1) Here, in the general formula (1), R- is a monovalent organic group represented by the following general formula (2), n is an integer of 1 to 150, and -X is an anionic functional group; H _{2m + 1} C _m -... (2) Here, m in the general formula (2) is an integer of 1 to 14. The method for manufacturing a sheet according to item 3 of the scope of patent application, wherein the aforementioned step of applying the aforementioned coating solution is such that the content of the aforementioned anionic surfactant in the aforementioned coating film is in each of the polyolefin resin foamed sheet. The unit area is implemented in a range of 3 mg / m ² or more and 100 mg / m ² or less.