JP2022049202A - Laminated porous sintered sheet - Google Patents

Abstract

To provide a laminated porous sintered sheet with excellent effective air permeability minus air leakage from the interface between the porous sheet and a double-sided adhesive sheet during adsorption and excellent adhesive strength at the interface between the porous sheet and the double-sided adhesive sheet.SOLUTION: The laminated porous sintered sheet has a porous sheet that is a sintered body of resin particles and a double-sided adhesive sheet with through holes in the thickness direction that is placed on one side of the porous sheet. A ratio R=(Φ1/Φ2) of a porosity Φ1 at the interface between the porous sheet and the double-sided adhesive sheet to a porosity Φ2 inside the porous sheet is 2.0 or more and 4.0 or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminated porous sintered sheet.

Conventionally, as a means for fixing or transporting a thin film, plate, or film such as a glass plate for liquid crystal or a green sheet for a laminated ceramic capacitor, the thin film, plate, or film is sucked under reduced pressure. A method of adsorbing and fixing or adsorbing and transporting a film-like object on an adsorption stage is known.
The adsorption stage is usually equipped with a porous resin body having air permeability as an adsorption cushioning material on the adsorption surface. This makes it possible to prevent scratches and contact marks from being generated on the member to be adsorbed. As such a resin porous body as an adsorption cushioning material, a sintered compact obtained by sintering and molding polyethylene powder is used from the viewpoint of rigidity, cushioning property and the like.

In recent years, liquid crystal screens and multilayer ceramic capacitors have become smaller and higher in performance, and glass plates for liquid crystals and green sheets for ceramic capacitors, which are raw materials, have become thinner. Therefore, it is necessary to perform very precise adsorption fixing or adsorption transfer.
Therefore, the adsorption cushioning material attached to the adsorption stage by vacuum suction is also required to have excellent surface smoothness and a surface structure for preventing scratches.
Regarding such a porous sheet as an adsorption cushioning material having excellent surface smoothness, Patent Document 1 proposes a method for producing a porous sheet by applying a dispersion liquid of fine particles on the porous sheet and then drying it.

When a porous sheet is attached to the adsorption stage, a laminated porous sintered sheet in which a double-sided adhesive sheet, a double-sided adhesive layer, or the like is arranged on the porous sheet is used.
The laminated porous sintered sheet is, for example, in Patent Document 2, a suction fixing sheet that prevents the suction object from coming into contact with the suction surface by arranging the suction device on the suction surface, and has a thickness. A porous sheet having air permeability in the direction, a double-sided adhesive sheet having a substrate and having air permeability in the thickness direction arranged on one surface of the porous sheet, or the porous sheet. A adsorption and fixing sheet having a substrate-less double-sided pressure-sensitive adhesive layer formed of a crosslinked pressure-sensitive adhesive and having air permeability in the thickness direction, which is arranged on one surface, has been proposed.

Japanese Unexamined Patent Publication No. 2007-283494 Japanese Unexamined Patent Publication No. 2019-52304

However, in the laminated porous sintered sheet that combines the porous sheet and the double-sided adhesive sheet as described above, air leaks from the interface between the porous sheet and the double-sided adhesive sheet during suction, and the laminated porous sheet is laminated in the thickness direction. There is a problem that the effective air flow rate of the porous sintered sheet is reduced, and it becomes difficult for air to flow in the porous sheet portion that is adhered to the non-opening portion of the double-sided adhesive sheet, resulting in variations in the suction force of the suction surface. Therefore, there is a problem that the suction force as a whole is lowered.
In addition, the adhesiveness between the porous sheet and the double-sided adhesive sheet is also an important factor, but it is necessary to adjust it in consideration of the balance between the air permeability in the thickness direction and the effective air permeability considering air leakage from the interface. be.

The porous sheet disclosed in Patent Document 1 has a problem that it does not have sufficient air permeability because it uses fine particles, and a double-sided adhesive sheet is attached to the porous sheet. The effective air volume and adhesive strength at the time have not been examined.
Further, the adsorption fixing sheet disclosed in Patent Document 2 prevents the adsorption fixing sheet from floating and shifting, increases the used area, and unintentionally deforms the adsorption target even when used at a high temperature. Alternatively, the purpose is to make it difficult to damage the surface, and the shape change that occurred on the surface of the object to be adsorbed during adsorption and the air permeability of the adsorption fixing sheet have been investigated, but both sides with the porous sheet during adsorption. The effective air volume and adhesive strength after deducting air leakage from the interface with the adhesive sheet have not been investigated.

Therefore, in the present invention, in view of the above-mentioned problems of the prior art, the effective air flow amount after deducting the air leakage from the interface between the porous sheet and the double-sided adhesive sheet at the time of adsorption is excellent, and the porous sheet and the double-sided adhesive sheet are excellent. It is an object of the present invention to provide a laminated porous sintered sheet having excellent adhesive strength at an interface.

As a result of diligent studies to solve the above problems, the present inventors have found that the above problems can be solved by controlling the state of the interface between the porous sheet and the double-sided adhesive sheet, and complete the present invention. I arrived.
That is, the present invention is as follows.

[1]
Porous sheet, which is a sintered body of resin particles,
It has a double-sided adhesive sheet having through holes in the thickness direction, which is arranged on one surface of the porous sheet.
The porosity Φ1 at the interface between the porous sheet and the double-sided adhesive sheet,
The ratio R = (Φ1 / Φ2) with the porosity Φ2 inside the porous sheet is
2.0 or more and 4.0 or less,
Laminated porous sintered sheet.
[2]
The porosity Φ1 at the interface between the porous sheet and the double-sided adhesive sheet is
The laminated porous sintered sheet according to the above [1], which is 40% or more and 80% or less.
[3]
The ratio of the average maximum diameter (average maximum diameter / average circle equivalent diameter) of the surface of the porous sheet on the side not in contact with the double-sided adhesive sheet to the average circle equivalent diameter of the surface opening is 2.0 or less. The laminated porous sintered sheet according to the above [1] or [2].
[4]
The laminated porous according to any one of the above [1] to [3], wherein the surface roughness (Ra) of the surface of the porous sheet on the side where the double-sided adhesive sheet is not arranged is 16 μm or less. Sintered sheet.
[5]
The laminated porous sintered sheet according to any one of the above [1] to [4], wherein the area ratio of the opening of the through hole to the total area of the double-sided adhesive sheet is 40% or more.
[6]
The laminated porous sintered sheet according to any one of the above [1] to [5], wherein the porous sheet contains a polyethylene resin.
[7]
The laminated porous sintered sheet according to the above [ ⁶ ], wherein the polyethylene-based resin has a viscosity average molecular weight Mv of 1.0 × 105 or more.
[8]
The laminated porous sintered sheet according to any one of the above [1] to [7], which is a sheet for adsorbing and fixing.

According to the present invention, the effective air volume is excellent after deducting air leakage from the interface between the porous sheet and the double-sided pressure-sensitive adhesive sheet at the time of adsorption, and the adhesive strength at the interface between the porous sheet and the double-sided pressure-sensitive adhesive sheet is excellent. A quality sintered sheet can be provided.

The X-ray CT measurement chart of the laminated porous sintered sheet of Example 1 is shown.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail.
It should be noted that the following embodiments are not intended to limit the present invention to the following contents, which is an example for explaining the present invention, and the present invention shall be variously modified and carried out within the scope of the gist thereof. Can be done.

[Laminated porous sintered sheet]
The laminated porous sintered sheet of this embodiment is
Porous sheet, which is a sintered body of resin particles,
A double-sided adhesive sheet having through holes in the thickness direction, which is arranged on one surface of the porous sheet, is provided.
The porosity Φ1 at the interface between the porous sheet and the double-sided adhesive sheet,
The ratio R = (Φ1 / Φ2) with the porosity Φ2 inside the porous sheet is
It is 2.0 or more and 4.0 or less.

(Porous sheet)
The porous sheet constituting the laminated porous sintered sheet of the present embodiment is a sintered body of resin particles, and is obtained by sintering the resin particles.
The thickness of the porous sheet is preferably 0.05 mm or more and 5 mm or less, more preferably 0.1 mm or more and 3 mm or less, and further preferably 0.2 mm or more and 2 mm or less. When the thickness of the porous sheet is within the above range, it tends to be more convenient and cost effective in handling. The thickness of the porous sheet can be measured by the method described in Examples.

The resin constituting the porous sheet is not particularly limited, and examples thereof include a thermoplastic resin and a thermosetting resin.
The thermoplastic resin is not particularly limited, but for example, a polyolefin resin, a polyester resin, a polyarylate, a liquid crystal polyester, a polyvinyl chloride, a polyvinyl alcohol, an ethylene vinyl acetate, a polystyrene, an acrylonitrile-butadiene-styrene copolymer resin, and the like. Examples thereof include acrylonitrile-styrene copolymer resin, polymethylmethacrylate, polyamide resin, polyacetal, polycarbonate, fluororesin, polyether ether ketone, polyether sulfone, polyphenylene sulfide and the like.
The thermosetting resin is not particularly limited, and specific examples thereof include a phenol resin, a urea resin, a melamine resin, an allyl resin, and an epoxy resin.
These resins may be used alone or in combination of two or more.

Among the above-mentioned resins, a thermoplastic resin is preferable from the viewpoint of shapeability, secondary processability and the like. Further, among the thermoplastic resins, polyolefin resins typified by polyethylene and polypropylene are more preferable.
Since the porous sheet contains a polyolefin resin, it is cheaper, has better chemical resistance and processability, and tends to have lower hygroscopicity and water absorption of the material.
Such a polyolefin-based resin is not particularly limited, but is, for example, a homopolymer of ethylene such as polyethylene; ethylene and one or more α-olefins such as propylene, butene-1, hexene-1, and octene-1. Copolymer with ethylene; copolymer of ethylene with vinyl acetate, acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, etc .; homopolymer of propylene such as polypropylene; and propylene with ethylene, Examples thereof include a copolymer with one or more α-olefins such as butene-1.
Among the polyolefin resins, polyethylene (homopolymer or copolymer) is preferable. By using polyethylene, the cost is lower, the sintering molding becomes easier, the processability and chemical resistance after molding are excellent, and the hygroscopicity and water absorption of the material itself tend to be lower.

The lower limit of the density of the resin used for the porous sheet is preferably 890 kg / m ³ or more, more preferably 920 kg / m ³ or more, still more preferably 930 kg / m ³ or more, and even more preferably 940 kg / m 3 or more. It is m ³ or more. When the lower limit of the density of the resin is within the above range, the rigidity of the porous sheet tends to be further improved.
The upper limit of the density of the resin used for the porous sheet is preferably 970 kg / m ³ or less, and more preferably 960 kg / m ³ or less. When the upper limit of the density of the resin is within the above range, the handleability at the time of manufacturing the porous sheet and the processability after molding tend to be further improved.

The viscosity average molecular weight (Mv) of the resin particles used in the porous sheet is preferably 100,000 or more and 8 million or less, and more preferably 300,000 or more and 8 million or less.
In particular, the viscosity average molecular weight (Mv) of the polyethylene resin used for the porous sheet is preferably 100,000 or more and 8 million or less, more preferably 200,000 or more and 6 million or less, and further preferably 300,000 or more and 3.5 million or less.
When the viscosity average molecular weight is within the above range, the flow of the resin, which is a factor that hinders the formation of pores during sintering and molding, tends to be smaller, and the fusion property of adjacent resin particles tends to be better.

The viscosity average molecular weight of the resin particles used in the porous sheet can be measured by the method described in Examples described later.
The viscosity average molecular weight of the resin particles can be controlled within the above numerical range by appropriately adjusting the polymerization conditions and the like. Specifically, the viscosity average molecular weight can be controlled by allowing hydrogen to exist in the polymerization system or changing the polymerization temperature.

The resin particles used in the porous sheet may be a mixed raw material of the same type of resin (for example, polyethylene-based resin) having different viscosity average molecular weights and the like, and may be a mixed raw material of different types of resin (for example, polyethylene-based resin and polyethylene-based resin). It may be a mixed raw material with the raw material resin).

The average particle size of the resin particles used in the porous sheet is preferably 30 μm or more and 300 μm or less, more preferably 40 μm or more and 250 μm or less, and further preferably 50 μm or more and 100 μm or less.
When the average particle size of the resin particles is within the above range, the air permeability of the obtained porous sheet tends to be further improved, and the balance between the strength and the rigidity tends to be excellent.
The average particle size of the resin particles is the particle size at which the cumulative mass is 50%, that is, the median size, and a laser diffraction type particle size distribution measuring device (“SALD-2100” manufactured by Shimadzu Corporation) is used. It can be measured using methanol as a dispersion medium.

The bulk density of the resin particles used in the porous sheet is preferably 0.20 g / cc or more and 0.65 g / cc or less, more preferably 0.30 g / cc or more and 0.60 g / cc or less, and further preferably. It is 0.40 g / cc or more and 0.58 g / cc or less.
When the bulk density is 0.20 g / cc or more, the mechanical strength tends to be further improved and the handleability tends to be further improved. Further, when the bulk density is 0.65 g / cc or less, the pore clogging is suppressed and the air permeability tends to be further improved.

The resin particles used in the porous sheet may be subjected to antistatic treatment using known means such as copolymerization with a monomer having a hydrophilic group, grafting of a monomer having a hydrophilic group, addition of a surfactant, and the like. .. In the antistatic treatment, an antistatic treated product may be formed into a porous body in a powder state to obtain an antistatic porous sheet, and a previously molded product may be formed into a porous sheet by a known method. Antistatic treatment may be performed.

(Double-sided adhesive sheet)
The laminated porous sintered sheet of the present embodiment has a double-sided pressure-sensitive adhesive sheet having through holes in the thickness direction, which is arranged on one surface of the above-mentioned porous sheet.
The double-sided pressure-sensitive adhesive sheet has a base material, a pressure-sensitive adhesive layer arranged on one surface of the base material, and a pressure-sensitive adhesive layer arranged on the other side.
The pressure-sensitive adhesive contained in each pressure-sensitive adhesive layer may be the same or different types. The pressure-sensitive adhesive to be bonded to the adsorption stage preferably has excellent re-peelability.
The base material of the double-sided pressure-sensitive adhesive sheet is not particularly limited, but for example, a resin is used. Examples of the resin for the base material include, but are not limited to, polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate (PET); polycarbonate (PC); and acrylic resins.
The resin is preferably PET or PC, and more preferably PET.
PET and PC are relatively hard as resin materials, and even when the area of the laminated porous sintered sheet of the present embodiment is large, the double-sided adhesive sheet is less likely to sag or wrinkle when bonded to the adsorption stage. In addition, PET and PC can maintain sufficient strength even when used at high temperatures.
The pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet is not particularly limited, and is, for example, polyester-based resin, acrylic-based resin, polyamide-based resin, silicone-based resin, modified silicone-based resin, phenol-based resin, and reactive hot. Existing products such as melt, polyamide resin hot melt, polyurethane hot melt, and polyolefin hot melt can be used. Acrylic resins are particularly preferable from the viewpoint of versatility.

The double-sided adhesive sheet has through holes in the thickness direction. Breathability can be ensured by the through hole.
The shape of the through hole of the double-sided pressure-sensitive adhesive sheet is not particularly limited, but for example, a circle, an ellipse, a square, or a rectangle is preferable, a circle or an ellipse is more preferable from the viewpoint of handleability, and a circle is further preferable.
Further, the shape of the through hole may be one type or two or more types may be used in combination.

The size of the through hole of the double-sided adhesive sheet is not particularly limited, but the long side is preferably 2 mm or more and 16 mm or less, and more preferably 4 mm or more and 12 mm or less in any shape. When the length of the long side is 2 mm or more, breathability is ensured, and when it is 16 mm or less, deformation of the porous sheet at the time of suction can be prevented.

The arrangement of the through holes of the double-sided adhesive sheet is not particularly limited, but the centers of the holes may be arranged in a square grid or a hexagonal grid, or may be randomly arranged.
Further, it is preferable that these through holes are distributed over the entire double-sided pressure-sensitive adhesive sheet, at least the entire region where the suction holes of the adsorption stage are located, from the viewpoint of uniformity of air flow rate.

The aperture ratio of the through hole of the double-sided adhesive sheet is the ratio of the area of the opening to the total area of the double-sided adhesive sheet.
The opening ratio of the through hole of the double-sided pressure-sensitive adhesive sheet is preferably 40% or more, more preferably 40% or more and 80% or less, further preferably 50% or more and 70% or less, still more preferably 50% or more and 60% or less. When the aperture ratio is 40% or more, sufficient air permeability can be ensured. Further, when it is 80% or less, the independence of the double-sided adhesive sheet can be maintained and the handling becomes easy. At the same time, the adhesive strength between the porous sheet and the adhesive sheet can be secured.

(Specific physical characteristics of laminated porous sintered sheet)
The laminated porous sintered sheet of the present embodiment includes the porous sheet and the double-sided pressure-sensitive adhesive sheet, and the two are bonded together.
The method of laminating these is not particularly limited, and examples thereof include a method of stacking a double-sided adhesive sheet on one surface of a porous sheet and applying pressure with a roller, a press machine, or the like.

<Porosity ratio R (Φ1 / Φ2)>
In the laminated porous sintered sheet of the present embodiment, the ratio R = (Φ1 / Φ2) of the porosity Φ1 at the interface between the porous sheet and the double-sided pressure-sensitive adhesive sheet and the porosity Φ2 inside the porous sheet is measured. , The interface between the porous sheet and the double-sided adhesive sheet and the air flowability inside the porous sheet can be evaluated.
The porosity ratio R of the laminated porous sintered sheet of the present embodiment is 2.0 or more and 4.0 or less, preferably 2.2 or more and 3.0 or less, and more preferably 2.4 or more and 2. It is 9 or less.
When the void ratio R is 2.0 or more, the flow of air sucked from the opening of the double-sided pressure-sensitive adhesive sheet spreads to the non-opening, so that the sucked air spreads in the entire surface direction, and the air The flow becomes uniform, the suction efficiency increases, and the overall air permeability increases.
Further, when the porosity ratio R is 4.0 or less, the flow of air sucked from the opening is connected to the direction parallel to the surface of the porous sheet, that is, to the open portion on the side surface, and from the porous sheet. It is possible to prevent the suction power of the material from decreasing. Hereinafter, this phenomenon is referred to as "vacuum leakage". In addition, the adhesive strength between the porous sheet and the double-sided adhesive sheet can be made sufficient.

The porosity Φ1 at the interface between the porous sheet and the double-sided pressure-sensitive adhesive sheet of the laminated porous sintered sheet of the present embodiment and the porosity Φ2 inside the porous sheet can be measured by using an X-ray CT apparatus.
For example, after obtaining a three-dimensional structure of a laminated porous sintered sheet using an X-ray CT device, a cross-sectional image is obtained step by step from one surface of the laminated porous sintered sheet in the thickness direction, and voids in each layer are obtained. The image of is binarized and the cross-sectional porosity is obtained. By this method, the profile of the porosity in the thickness direction of the laminated porous sintered sheet can be obtained.
The porosity Φ1 at the interface between the porous sheet and the double-sided pressure-sensitive adhesive sheet is determined at the interface with the double-sided pressure-sensitive adhesive sheet when the change in porosity is followed from the porous sheet side of the laminated porous sintered sheet in the profile of the porosity. , The highest value before the porosity drops sharply to 0% due to the presence of the double-sided adhesive sheet.
In the porosity profile, the porosity Φ2 inside the porous sheet is the portion from the surface of the side of the porous sheet without the double-sided adhesive sheet to 80 μm inward, and the porous sheet of the laminated porous sintered sheet. When following the change in porosity from the side, the region (porous) excluding the part where the porosity became 0% due to the presence of the double-sided adhesive sheet and the part up to 80 μm inward at the interface with the double-sided adhesive sheet. The average value of the inside of the sheet). In addition, this measurement is performed in the portion of the double-sided adhesive sheet where there is no through hole.
Since the laminated porous sintered sheet of the present embodiment has a porosity ratio R in the above range, the porosity Φ1 at the interface is larger than the porosity Φ2 inside the porous sheet, and the air sucked from the adsorption stage. The flow of the double-sided pressure-sensitive adhesive sheet can be distributed over the entire porous sheet so that the adhesive force of the double-sided adhesive sheet to the porous sheet is sufficient.

In order to obtain such a laminated porous sintered sheet, that is, to control the porosity ratio R of the laminated porous sintered sheet within the above range, it is possible to control the state of the interface between the porous sheet and the double-sided pressure-sensitive adhesive sheet. is important.
As a method of controlling the state of the interface between the porous sheet and the double-sided adhesive sheet, (1) the surface on which the double-sided adhesive sheet of the porous sheet is arranged is not filled with the interface space even if the double-sided adhesive sheet is attached. (2) A method of adjusting the adhesive layer on the side in contact with the porous sheet of the double-sided adhesive sheet so that the interface space is not filled even if the adhesive layer is bonded to the porous sheet, and (3) Porous. A method of preventing the space at the interface from being filled when the sheet and the double-sided adhesive sheet are bonded to each other can be mentioned.
As a method of adjusting the surface of the (1) porous sheet on which the double-sided adhesive sheet is arranged so that the space at the interface is not filled even if the double-sided adhesive sheet is attached, the surface on which the double-sided adhesive sheet is arranged is appropriately adjusted. There is a method of arranging large particles and melting and fusing the particles more than necessary to prevent the surface from becoming smooth when sintering. Specifically, a method of using two or more types of powder with a particle size and placing a powder with a fine particle size first and sintering it, or using a powder with a particle size distribution and vibrating the hopper to classify. When heating in an oven after depositing resin particles on an endless conveyor belt, the upper temperature is set to a range of 10 ° C higher than the melting point of the resin particles in the first heating zone, and the lower temperature is set to 10 ° C higher than the melting point of the resin particles. The side is set to 60 ° C to 70 ° C or higher, which is the melting point of the resin particles, and heated for 4 to 6 minutes. In the second heating zone, the upper temperature is 40 ° C to 50 ° C higher than the melting point of the resin particles, and the lower temperature. Is set to 60 ° C. to 70 ° C. or higher than the melting point of the resin particles and heated for 2 to 3 minutes. A method of heating for up to 6 minutes can be mentioned.
As a method of adjusting the adhesive layer on the side of the double-sided adhesive sheet in contact with the porous sheet so that the space at the interface is not filled even when the adhesive layer is bonded to the porous sheet, the adhesive layer is immersed in the porous sheet more than necessary. The use of a non-penetrating adhesive layer is mentioned. Specifically, the holding force of the adhesive on the side to be bonded to the porous sheet is 1.0 mm / 50,000 seconds or less, preferably 0.5 mm / 50,000 seconds. The thickness of the adhesive layer on the side to be bonded to the porous sheet may be 10 μm or more and 30 μm or less. The holding force can be measured as follows. The test piece is cut into a width of 25 mm and a length of 130 mm. The end "25 mm x 25 mm" portion of the test piece is attached to one end of the test plate and crimped once with a 1 kg roller. After crimping, the mixture is left at a temperature of 23 ± 2 ° C. for 1 hour, and after a predetermined time, a 9.8 N weight is hung from the lower end of the test piece, and the distance at which the weight is displaced is measured after 50,000 seconds.
As a method of preventing the space at the interface from being filled when the porous sheet and the double-sided adhesive sheet are bonded, the pressure-sensitive adhesive layer should not be infiltrated into the porous sheet more than necessary during the bonding. To do. The method of applying pressure is not particularly limited, and examples thereof include a method of pressing with a rubber roller and a method of pressing with a metal press. Specifically, the porous sheet is preheated at a temperature of 50 ° C. or higher and 80 ° C. or lower at the time of bonding, and pressed at 0.05 or more and 0.15 MPa or less at the time of bonding for 5 or more and 10 seconds or less.

<Porosity Φ1 at the interface>
The porosity Φ1 at the interface between the porous sheet and the double-sided pressure-sensitive adhesive sheet of the laminated porous sintered sheet of the present embodiment is preferably 40% or more and 80% or less, more preferably 50% or more and 70% or less, and further. It is preferably 50% or more and 60% or less.
By setting the porosity Φ1 at the interface to 40% or more, the air flow in the plane direction can be ensured, and the overall air permeability can be ensured. Further, when it is set to 80% or less, the adhesive strength between the porous sheet and the adhesive sheet can be secured.
The method for measuring Φ1 is as described above.

As a method of controlling the void ratio Φ1 at the interface within the above range, in a method of depositing resin particles on an endless conveyor belt in a continuous sintering step when obtaining a porous sheet and then heating in an oven, the heating is performed. At this time, in the first heating zone, the upper temperature is set in the range of 10 ° C higher than the melting point of the resin particles to the melting point, and the lower temperature is set to 60 ° C to 70 ° C or higher of the melting point of the resin particles and heated for 4 to 6 minutes. In the second heating zone, the upper temperature is set to 40 ° C to 50 ° C higher than the melting point of the resin particles, and the lower temperature is set to 60 ° C to 70 ° C or higher than the melting point of the resin particles, and heating is performed for 2 to 3 minutes. However, in the third heating zone, a method of raising the temperature of the upper side and the lower side by 60 ° C. to 70 ° C. higher than the melting point of the resin particles and heating for 4 to 6 minutes can be mentioned.
Further, in the method using a mold in the step of sintering resin particles, powder having a small particle size is spread on the bottom surface of the mold laid sideways, and then particles having a large particle size are spread on the powder. A method of sintering can be mentioned.
Further, the holding force of the surface to be bonded to the porous sheet of the double-sided adhesive sheet to be used is 1.0 mm / 50,000 seconds or less, preferably 0.5 mm / 50,000 seconds or less, and the thickness is 1 μm or more and 50 μm or less, preferably 10 μm. When the double-sided pressure-sensitive adhesive sheet and the porous sheet are bonded together, the porous sheet is preheated to 50 ° C. or higher and 80 ° C. or lower in advance, and the press machine is used at 0.05 or higher and 0.15 MPa or lower for 5 seconds. Examples thereof include a method of pressing for 10 seconds or less.

<Ratio of the average maximum diameter to the average circle equivalent diameter of the opening on the surface of the surface on the side where the double-sided adhesive sheet of the laminated porous sintered sheet is not arranged>
The ratio of the average maximum diameter to the average circle equivalent diameter (average maximum diameter / average circle equivalent diameter) of the opening on the surface of the surface of the laminated porous sintered sheet of the present embodiment on the side where the double-sided adhesive sheet is not arranged is 2. It is preferably 0.0 or less, more preferably 1.0 or more and 2.0 or less, still more preferably 1.0 or more and 1.9 or less, and even more preferably 1.3 or more and 1.7 or less.
When the ratio of the average maximum diameter to the average circle equivalent diameter is within the above range, scratches and contact marks are generated on the adsorbed member when the laminated porous sintered sheet of the present embodiment is used as an adsorption cushioning material. Can be prevented more effectively.

The ratio of the average maximum diameter to the average circle equivalent diameter is obtained as follows.
The surface of the surface of the laminated porous sintered sheet on the side where the double-sided adhesive sheet is not arranged is measured with a shape measurement laser microscope (“VK-X100” manufactured by KEYENCE) with an objective lens of 10 times, and 5 × The images of 5 are connected to obtain a field of view of 6284 μm in width × 3658 μm in length.
Using the analysis application (VK-H1X4A: Ver.3.4) attached to the device in this field of view, the value between the lowest part and the highest part is set to 100% from the obtained shape data, and the threshold value is 2 from the lowest part to 30%. Threshold and identify the opening.
The area of up to 1000 of these openings is obtained, and the equivalent circle diameter and the maximum diameter are obtained from the results. Calculate the average value of each and calculate the ratio of the average maximum diameter to the average circle equivalent diameter.

As a method of setting the ratio of the average maximum diameter to the average circle equivalent diameter to 2.0 or less, preferably 1.0 or more and 2.0 or less, for example, when obtaining a porous sheet, in continuous sintering, an endless conveyor is used. In the method of depositing resin particles on a belt and then heating in an oven, in the first heating zone, the upper temperature is set in the range of 10 ° C. higher than the melting point of the resin particles, and the lower temperature is 60, which is the melting point of the resin particles. Set to ° C to 70 ° C or higher and heat for 4 to 6 minutes. In the second heating zone, the upper temperature is 40 ° C to 50 ° C higher than the melting point of the resin particles, and the lower temperature is 60 ° C higher than the melting point of the resin particles. There is a method of setting the temperature to about 70 ° C. or higher and heating for 2 to 3 minutes, and in the third heating zone, raising the temperature of the upper side and the lower side by 60 ° C. to 70 ° C. higher than the melting point of the resin particles and heating for 4 to 6 minutes. ..
In addition, in the method of using a mold for sintering, there is a method in which powder having a small particle size is spread on the bottom surface of the mold laid sideways, and particles having a large diameter are spread on the bottom surface and then sintered. Can be mentioned.

<Surface roughness (Ra) of the surface of the laminated porous sintered sheet on the side where the double-sided adhesive sheet is not arranged>
The surface roughness (Ra) of the surface of the laminated porous sintered sheet of the present embodiment on the side where the double-sided adhesive sheet is not arranged is preferably 16 μm or less, more preferably 3 μm or more and 16 μm or less, and further preferably. It is 3 μm or more and 12 μm or less, and more preferably 3 μm or more and 10 μm or less.
When the surface roughness Ra is within the above range, when the laminated porous sintered sheet of the present embodiment is used as an adsorption cushioning material, scratches and contact marks are more effectively prevented on the adsorbed member. be able to.

As a method for adjusting the surface roughness (Ra) of the surface of the laminated porous sintered sheet on the side where the double-sided adhesive sheet is not arranged within the above range, for example, a method of producing a porous sheet by a deposition method can be obtained. Examples thereof include a method of producing a porous sheet by cutting a porous sintered body, a method of pressing the produced porous sheet with a hot press, and the like.
The surface roughness (Ra) is a stylus type surface roughness meter (“Handy Surf E-35B” manufactured by Tokyo Seimitsu Co., Ltd.), tip diameter R: 5 μm, speed: 0.6 mm / s, measurement length: It can be measured under the conditions of 12.5 mm, a cutoff value λc: 2.5 mm, and the number of measurements: n = 5.

[Manufacturing method of laminated porous sheet]
The laminated porous sheet of the present embodiment can be obtained by manufacturing a porous sheet and a double-sided pressure-sensitive adhesive sheet by a manufacturing method described later and laminating them.

(Manufacturing method of porous sheet)
The porous sheet constituting the laminated porous sintered sheet of the present embodiment can be manufactured by using a known sintering molding method.
The sintering molding method is not particularly limited as long as it is a method of obtaining a porous sheet by sintering resin particles, and for example, a "sedimentation method" for obtaining a porous sheet through a deposition step and a sintering step. , "Mold method" in which resin particles are filled in a mold and sintered.

<Deposition method>
The deposition method is a method for producing a porous sheet, which includes a deposition step and a sintering step.
The deposition step and the sintering step can also be performed as a continuous step. Such a deposition method is preferable from the viewpoint of continuous productivity of the porous sheet and the degree of freedom in thickness.
Examples of the deposition step in the deposition method include a method of depositing resin particles in a sheet shape on an endless conveyor belt by vibrating a raw material hopper filled with resin particles.
When the resin particles are supplied onto the endless conveyor belt, the raw material hopper filled with the resin particles is vibrated, so that the raw material resin particles can be uniformly deposited. The moving speed of the supply roller under the raw material hopper is preferably 3% to 5% slower than the moving speed of the endless conveyor belt.
The sintering step in the deposition method is a step of obtaining a porous sheet by sintering resin particles deposited in the form of a sheet. The sintering temperature is not particularly limited, but is preferably Tm to Tm + 80 ° C., more preferably Tm to Tm + 70 ° C., and even more preferably Tm to Tm + 60 ° C., based on the melting point Tm of the resin used. A more specific sintering temperature is preferably 190 ° C. to 230 ° C., although it depends on the resin type.
The sintering time depends on the fluidity of the resin, but is preferably 1 minute to 30 minutes, more preferably 3 minutes to 20 minutes, and further preferably 5 minutes to 15 minutes.
When producing the porous sheet, after the sintering step, a compression step of compressing the porous sheet may be further performed by using a heated pressure roller. Further, instead of the pressure roller, a pressure member such as a pressure plate or an endless belt-shaped pressure device can be used for pressure compression. After the compression process, the porous sheet is quickly peeled off from the pressure member. It is preferable to cool it.

<Mold method>
The mold method is a method for producing a porous sheet by filling a mold with resin particles and sintering the mold.
For example, when forming a sheet-shaped sintered porous body, resin particles are filled in the gaps between two metal (for example, aluminum) plates adjusted so that the porous sheet has a desired thickness, and then resin particles are filled. Examples thereof include a method in which a porous sintered body having continuous pores is taken out from a mold by putting it in a heating furnace whose temperature is maintained above the melting point, sintering it, and then cooling it.
Then, the obtained porous sintered body is sliced or skived to obtain a porous sheet.
After filling the resin particles, the mold is placed horizontally and vibrated by a vibrator, so that finer particles can be unevenly distributed on one side of the sheet.

(Hydrophilic resin)
In the process of manufacturing the porous sheet, the resin particles may be used after being mixed with the surfactant.
The surfactant is not particularly limited, and examples thereof include polyoxysorbitan monolaurate and the like.
In the method for producing a porous sheet constituting the laminated porous sintered sheet of the present embodiment, a method of using powders having two or more kinds of particle sizes and placing a powder having a fine particle size first and sintering the sheets, or It is preferable to use a powder having a particle size distribution and vibrate the hopper to classify and place the powder on it for sintering.

(Preferable form by deposition method)
In the porous sheet constituting the laminated porous sintered sheet of the present embodiment, the upper temperature is set in the range of 10 ° C. higher than the melting point to the melting point of the resin particles in the first heating zone, and the lower temperature is the melting point of the resin particles. Set to 60 ° C to 70 ° C or higher and heat for 4 to 6 minutes. In the second heating zone, the temperature on the upper side is 40 ° C to 50 ° C higher than the melting point of the resin particles, and the temperature on the lower side is 60 from the melting point of the resin particles. It is preferable to set the temperature to ℃ to 70 ℃ or higher and heat for 2 to 3 minutes, and in the third heating zone, raise the upper and lower temperatures by 60 ℃ to 70 ℃ above the melting point of the resin particles and heat for 4 to 6 minutes. ..
By heating in this way, the surface on the side on which the double-sided adhesive sheet is arranged can be sintered without heating more than necessary, leaving irregularities.

(Manufacturing method of double-sided adhesive sheet)
The double-sided adhesive sheet constituting the laminated porous sintered sheet of the present embodiment is formed by applying, for example, punching with a Thomson blade, laser irradiation, or a method using a plotter cutter to the double-sided adhesive sheet having no predetermined through hole. It can be manufactured by forming.

(Laminating method)
The laminated porous sintered sheet of the present embodiment can be obtained by laminating the porous sheet produced as described above and the double-sided pressure-sensitive adhesive sheet.
The method of laminating these is not particularly limited, and examples thereof include a method of pressing a double-sided adhesive sheet against a porous sheet with a rubber roller, a method of pressing with a metal press machine, and the like.
In the laminated porous sintered sheet of the present embodiment, when the porous sheet and the double-sided pressure-sensitive adhesive sheet are bonded together, the porous sheet is preheated to 50 ° C. or higher and 80 ° C. or lower in advance, and 0.05 or higher in a press machine. It is preferable to press at 0.15 MPa or less for 5 or more and 10 seconds or less.

[Use]
The laminated porous sintered sheet of the present embodiment has excellent breathability and surface smoothness, and has an adhesive layer, so that it can be easily replaced with a substrate to be bonded, and is therefore suitable as an adsorption cushioning material. Can be used.
The adsorption cushioning material is an adsorption fixing or adsorption at an adsorption stage with vacuum suction in order to fix or convey a thin film, plate, or film such as a glass plate for liquid crystal or a sheet for a laminated ceramic capacitor. In the method of transporting, it is attached to the suction surface of the suction stage.
That is, the laminated porous sintered sheet of the present embodiment can be suitably used as a sheet for adsorbing and fixing and transporting.
Examples of the thin film include a ceramic green sheet.
Ceramic green sheets are usually ceramic powders, binders (acrylic resins, butyral resins, etc.), plasticizers (phthalates, glycols, adipic acids, phosphate esters) and organic solvents (toluene, MEK, acetone). Etc.) was prepared, and this ceramic paint was applied onto a carrier sheet by a doctor blade method or the like and dried by heating.

Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples.
The measurement of each physical property of each material was performed as follows.

[Porosity Φ1 at the interface between the porous sheet and the double-sided adhesive sheet]
Using an X-ray CT device (micro focus X-ray CT system HPCinspeXioSMX-225CT: manufactured by Shimadzu Corporation), X-ray conditions are 160 kV / 40 μA, no metal filter, and shooting conditions are 1200 images with an exposure time of 0.33 seconds / A three-dimensional structure of a laminated porous sintered sheet was obtained at an image size of 1024 × 1024 pix and a spatial resolution of 5 μm / pix at 360 ° rotation.
A cross-sectional image was obtained from one surface of the laminated porous sintered sheet in each step in the thickness direction, and the voids of each layer were binarized by the Otsu method of the image to obtain the cross-sectional porosity.
By this method, the profile of the porosity in the thickness direction of the laminated porous sintered sheet was obtained.
The porosity Φ1 at the interface between the porous sheet and the double-sided adhesive sheet is 0% due to the presence of the double-sided adhesive sheet at the interface with the double-sided adhesive sheet when the change in the porosity is followed from the porous sheet side. The highest price before the plunge.

[Ratio R of the porosity Φ1 and the porosity Φ2 inside the porous sheet]
In the porosity profile, the porosity is 0% on the side without the double-sided adhesive sheet, except for the portion from the surface to the inside of 80 μm, and on the side with the double-sided adhesive sheet, due to the presence of the double-sided adhesive sheet. The average value of the porosity in the region excluding the portion having a porosity of 80 μm inside was defined as the porosity Φ2 inside the porous sheet.
These ratios (Φ1 / Φ2) were defined as the porosity ratio R.

[Ratio of average maximum diameter to average circle equivalent diameter]
The surface of the surface of the laminated porous sintered sheet on the side where the double-sided adhesive sheet is not arranged is measured with a shape measurement laser microscope (“VK-X100” manufactured by KEYENCE) with an objective lens of 10 times, and 5 × The images of 5 were concatenated to obtain a field of view of 6284 μm in width × 3658 μm in length.
Using the analysis application (VK-H1X4A: Ver.3.4) attached to the device in this field of view, the value between the lowest part and the highest part is set to 100% from the obtained shape data, and the threshold value is 2 from the lowest part to 30%. It was binarized and the opening was identified.
The area of up to 1000 of these openings was determined, and from the results, the equivalent circle diameter and the maximum diameter were determined.
The average value of these was calculated, and the ratio of the average maximum diameter to the average circle equivalent diameter (average maximum diameter / average circle equivalent diameter) was obtained.

[Surface roughness (Ra)]
Using a stylus type surface roughness meter ("Handy Surf E-35B" manufactured by Tokyo Seimitsu Co., Ltd.), tip diameter R: 5 μm, speed: 0.6 mm / s, measurement length: 12.5 mm, cutoff value λc : Under the condition of 2.5 mm, the surface roughness Ra of the surface of the laminated porous sintered sheet on the side where the double-sided adhesive sheet was not arranged was measured.
As for the measurement positions, one point at the center of the surface of the porous sheet and one point at the center of the four equal parts when the surface is divided into four equal parts so as to have the same shape as possible, a total of five points are measured. , The average value was calculated, and this was taken as the surface roughness Ra.

[Viscosity average molecular weight (Mv)]
The viscosity average molecular weight of the polyethylene resin was measured according to ISO1628-3 (2010) by the method shown below.
First, polyethylene resin particles are weighed in the dissolution tube within the range of 4.0 to 4.5 mg (the weighed mass is expressed as "m" in the following formula), and the air inside the dissolution tube is pumped. 20 mL of decahydronaphthalene (2,6-di-t-butyl-4-methylphenol added 1 g / L) degassed with, degassed with nitrogen, degassed with a vacuum pump and replaced with nitrogen, and the following , Decalin) was added, and the mixture was stirred at 150 ° C. for 90 minutes to dissolve the polyethylene resin particles to prepare a decalin solution.
After that, the decalin solution was put into a Cannon-Fenceke viscometer (manufactured by Shibata Kagaku Kikai Kogyo Co., Ltd./viscometer number: 100) in a constant temperature liquid bath at 135 ° C., and the drop time (ts) between marked lines was measured. did.
Further, the drop time (tb) of decalin alone without polyethylene resin particles as a blank was measured, and the specific viscosity (ηsp) was determined according to the following (Formula A).
ηsp = (ts / tb) -1 (Formula A)
From the specific viscosity (ηsp) and the concentration (C) (unit: g / dL), the ultimate viscosity IV was calculated using the following (Formula B) and (Formula C).
Concentration C = m / (20 × γ) / 10 (Unit: g / dL) (Formula B)
γ = (Density of decalin at 20 ° C) / (Density of decalin at 135 ° C)
= 0.888 / 0.802 = 1.107
Extreme Viscosity IV = (ηsp / C) / (1 + 0.27 × ηsp) (Formula C)
This limit viscosity IV was substituted into the following (Formula D) to determine the viscosity average molecular weight (Mv).
Viscosity average molecular weight (Mv) = (5.34 × 10 ⁴ ) × [η] ^1.49 (Formula D)

[Draft]
The air permeability of the laminated porous sheet was measured using an air permeability measuring machine (“FX3360 PORTAIR” manufactured by TEXTEST) under the conditions of a measuring range of 20 cm ² and a measurement differential pressure of 125 Pa, and evaluated based on the following criteria.
〇: Air permeability is 8 cm ³ / cm ² / sec or more △: Air permeability is 5 cm ³ / cm ² / sec or more and less than 8 cm ³ / cm ² / sec ×: Air permeability is less than 5 cm ³ / cm ² / sec

[Vacuum leak]
The vacuum leakage of the laminated porous sintered sheet was measured by the following method.
A polyethylene terephthalate sheet having a thickness of 25 μm as a non-breathable sheet was attached to the surface of the laminated porous sintered sheet on the porous sheet side with a spray glue, and the air permeability was measured by the above-mentioned air permeability measuring machine.
This air permeability was used as the value of vacuum leakage and evaluated based on the following criteria.
〇: Air permeability is less than 0.15 cm ³ / cm ² / sec Δ: Air permeability is 0.15 cm ³ / cm ² / sec or more 0.20 cm ³ / cm ² / sec Insufficient ×: Air permeability is 0.20 cm ³ / Cm ² / sec or more

[Adhesive strength]
The adhesive strength between the porous sheet and the double-sided adhesive sheet in the laminated porous sintered sheet was measured by the following method.
The laminated porous sintered sheet was cut into a size of 2.5 cm in width and 20 cm in length, the release paper of the double-sided adhesive sheet was peeled off, and the sheet was attached to a stainless plate having a thickness of 5 cm × 20 cm and a thickness of 2 mm.
The porous sheet was peeled off from the double-sided adhesive sheet by about 2 cm, and the peeled double-sided adhesive sheet was attached to a stainless steel plate with masking tape. The peeled porous sheet was peeled off at a speed of 100 mm / min at an angle of 90 °, and the strength at that time was measured and evaluated based on the following criteria.
〇: Strength is less than 2.2N / 25mm ×: Strength is 2.2N / 25mm or more

〔Comprehensive evaluation〕
The comprehensive evaluation of the laminated porous sintered sheet was performed by evaluating the balance between the air permeability, the vacuum leakage, and the adhesive force, and evaluated based on the following criteria.
〇: The above three items, that is, the evaluation of air permeability, vacuum leakage, and adhesive strength are all 〇 △: One of the above three items is △ or × ×: Items other than 〇, △, XX XX : At least two of the above three items are x

[Evaluation of adsorption state]
The laminated porous sintered sheet is attached to a suction stage (an aluminum plate with a thickness of 15 mm and a length and width of 200 mm, and vents with a diameter of 1 mm are provided at a pitch of 10 mm in length and width so that suction can be performed from one side with a suction pump). A silver foil having a thickness of 50 μm was adsorbed and fixed at a pressure of 60 Pa via a laminated porous sintered sheet, and it was visually confirmed whether or not unevenness was observed on the surface of the silver foil, and evaluation was performed based on the following criteria.
〇: No unevenness that can be visually confirmed.
×: Those with irregularities that can be visually confirmed.

[Example 1]
0.3 parts by mass of polyoxysorbitan monolaurate with respect to 100 parts by mass of ultra-high molecular weight polyethylene (PE) having a viscosity average molecular weight (Mv) of 300,000, an average particle size of 97 μm, and a bulk density of 0.53 g / cc. It was added and mixed with a blender to obtain an ultra-high molecular weight polyethylene composition.
The ultra-high molecular weight polyethylene composition was put into a hopper and the roller at the lower part of the hopper was rotated at a moving speed (circumference) of 9.5 cm / min to supply the ultra-high molecular weight polyethylene composition.
The supplied ultra-high molecular weight polyethylene composition was heated to 140 ° C. and deposited on a metal endless conveyor belt rotating at a moving speed of 10 cm / min to a thickness of 0.505 mm.
Next, the first heating zone set at 120 ° C. on the upper side and 190 ° C. on the lower side is passed over 5 minutes, and then the second heating zone set at 160 ° C. on the upper side and 200 ° C. on the lower side is passed. It was passed over 3 minutes and then through a third heating zone set at 200 ° C. on the upper side and 200 ° C. on the lower side over 5 minutes.
The temperature of the ultra-high molecular weight polyethylene composition at the outlet of the heating zone was 190 ° C.
After 15 seconds, it was peeled off from the endless conveyor belt to obtain the original fabric of the porous sintered body.
Subsequently, the raw fabric of the porous sintered body was pressure-pressed at 100 ° C. at a mold thickness of 0.500 mm under the condition of 1 MP for 90 seconds to obtain a porous sheet having a thickness of 0.501 mm.
Next, Nissei Shinka's double-sided adhesive sheet NE-take transparent PET21-WF-R / S (the base material is a polyester film with a thickness of 21 μm, and the re-peelable side (the side to be attached to the adsorption stage) is acrylic. The pressure-sensitive adhesive RC-910 was formed with a thickness of 15 μm, and the acrylic pressure-sensitive adhesive L-100 was formed with a thickness of 25 μm on the strong adhesive side (the side to be attached to the porous sheet). A circular hole having a diameter of 9 mm was formed over the entire surface so that the distance between the centers was 12 mm in a hexagonal lattice, and an opening was formed in the double-sided adhesive sheet.
The area ratio of the opening to the whole was 50%.
Next, the porous sheet was placed on the lower plate of a metal press heated to 80 ° C. with the side in contact with the endless conveyor belt facing down for 60 seconds to preheat the porous sheet, and then the above. A laminated porous sintered sheet was obtained by lightly pressing the strongly adhesive side of the double-sided adhesive sheet having an opening and then pressing at 0.1 MPa for 10 seconds.
The profile of the cross-sectional porosity of the obtained laminated porous sintered sheet is shown in FIG.
The characteristics of the laminated porous sintered sheet are shown in Table 1 below.

[Example 2]
A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that ultra-high molecular weight polyethylene having an average particle size of 120 μm and a bulk density of 0.48 g / cc was used.
The characteristics of the laminated porous sintered sheet are shown in Table 1 below.

[Example 3]
A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that ultra-high molecular weight polyethylene having a viscosity average molecular weight (Mv) of 3.4 million, an average particle size of 101 μm, and a bulk density of 0.42 g / cc was used. rice field.
The characteristics of the laminated porous sintered sheet are shown in Table 1 below.

[Example 4]
A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that ultra-high molecular weight polyethylene having an average particle size of 50 μm and a bulk density of 0.58 g / cc was used.
The characteristics of the laminated porous sintered sheet are shown in Table 1 below.

[Example 5]
A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that the polyethylene used in Example 3 and Example 4 were mixed and used in an amount of 50 parts by mass.
The characteristics of the laminated porous sintered sheet are shown in Table 1 below.

[Example 6]
A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that the temperature conditions of the heating zone were changed as follows.
A heating zone set at 200 ° C. on the upper side and 200 ° C. on the lower side was passed over 8 minutes.
The resin temperature at the outlet of the heating zone was 190 ° C.

[Example 7]
A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that the pressure condition for bonding the porous sheet and the double-sided adhesive sheet was set to be pressed at 0.5 MPa for 20 seconds.
The characteristics of the laminated porous sintered sheet are shown in Table 1 below.

[Example 8]
A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that ultra-high molecular weight polyethylene having a viscosity average molecular weight (Mv) of 6.5 million, an average particle size of 151 μm, and a bulk density of 0.42 g / cc was used. ..
The characteristics of the laminated porous sintered sheet are shown in Table 1 below.

[Example 9]
As a double-sided adhesive sheet, NE-take transparent PET21-WF-R / S manufactured by Nikkei Shinka has a circular hole with a diameter of 7 mm drilled over the entire surface so as to form a hexagonal grid with a center-to-center distance of 11 mm. A laminated porous sintered sheet was obtained in the same manner as in Example 3 except that the area ratio of the opening to the whole was 37%).
The characteristics of the laminated porous sintered sheet are shown in Table 1 below.

[Comparative Example 1]
A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that ultra-high molecular weight polyethylene having a viscosity average molecular weight (Mv) of 50,000, an average particle size of 97 μm, and a bulk density of 0.53 g / cc was used. ..
The characteristics of the laminated porous sintered sheet are shown in Table 2 below.

[Comparative Example 2]
A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that ultra-high molecular weight polyethylene having a viscosity average molecular weight (Mv) of 8.5 million, an average particle size of 200 μm, and a bulk density of 0.40 g / cc was used. ..
The characteristics of the laminated porous sintered sheet are shown in Table 2 below.

[Comparative Example 3]
A porous sheet was obtained in the same manner as in Example 1 except that the temperature conditions of the heating zone were changed as follows.
A heating zone set at 200 ° C. on the upper side and 200 ° C. on the lower side was passed over 8 minutes.
The resin temperature at the outlet of the heating zone was 190 ° C.
Using the obtained porous sheet and the same double-sided adhesive sheet as in Example 1, the press machine for bonding was not heated, and the conditions were set to 0.2 MPa for 10 seconds to obtain a laminated porous sintered sheet.
The characteristics of the laminated porous sintered sheet are shown in Table 2 below.

[Comparative Example 4]
Using the same ultra-high molecular weight polyethylene as in Example 1, the aluminum mold adjusted to a clearance of 1.0 mm was filled with the ultra-high molecular weight polyethylene while vibrating with a vibrator for 30 seconds, and the mold temperature was 200 ° C. After heating and cooling until the temperature became low, the mold was released to obtain a porous sheet having a thickness of 0.99 mm.
A double-sided pressure-sensitive adhesive sheet was attached to the obtained porous sheet by the same method as in Example 1 to obtain a laminated porous sintered sheet.
The characteristics of the laminated porous sintered sheet are shown in Table 2 below.

[Comparative Example 5]
Using the same ultra-high molecular weight polyethylene as in Example 1, the mesh-shaped cylindrical mold (inner diameter 250 mm, height 500 mm) was filled, and the ultra-high molecular weight polyethylene was filled while vibrating with a vibrator for 30 seconds.
This is placed in a pressure-resistant container, steam (160 ° C., 8 atm) is introduced, heat-sintered for 10 hours, and then left at room temperature of 25 ° C. for cooling to obtain a cylindrical porous sintered body block. rice field.
By cutting the obtained cylindrical porous sintered body block, a porous sheet having a thickness of 0.50 mm was obtained.
A double-sided pressure-sensitive adhesive sheet was attached to the obtained porous sheet by the same method as in Example 1 to obtain a laminated porous sintered sheet.
The characteristics of the laminated porous sintered sheet are shown in Table 2 below.

[Comparative Example 6]
A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that the pressure was 0.02 MPa when the porous sheet and the double-sided adhesive sheet were attached.
The characteristics of the laminated porous sintered sheet are shown in Table 2 below.

[Comparative Example 7]
Ultra-high molecular weight polyethylene with a viscosity average molecular weight (Mv) of 300,000, an average particle size of 120 μm, and a bulk density of 0.48 g / cc is used, and is used on the strong adhesive side (the side to be attached to the porous sheet) for the double-sided adhesive sheet. A laminated porous sintered sheet was obtained in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive L-100 was changed to a thickness of 8 μm.
The characteristics of the laminated porous sintered sheet are shown in Table 2 below.

The laminated porous sintered sheet of the present invention is an adsorption cushioning material used for fixing or transporting a thin film, plate, or film such as a glass plate for liquid crystal and a green sheet for a laminated ceramic capacitor. It has industrial applicability as a fixed transport sheet.

Claims (8)

Porous sheet, which is a sintered body of resin particles,
A double-sided adhesive sheet having through holes in the thickness direction, which is arranged on one surface of the porous sheet, is provided.
The porosity Φ1 at the interface between the porous sheet and the double-sided adhesive sheet,
The ratio R = (Φ1 / Φ2) with the porosity Φ2 inside the porous sheet is
2.0 or more and 4.0 or less,
Laminated porous sintered sheet. The porosity Φ1 at the interface between the porous sheet and the double-sided adhesive sheet is
40% or more and 80% or less,
The laminated porous sintered sheet according to claim 1. The ratio of the average maximum diameter (average maximum diameter / average circle equivalent diameter) of the surface of the porous sheet on the side not in contact with the double-sided adhesive sheet to the average circle equivalent diameter of the surface opening is 2.0 or less. be,
The laminated porous sintered sheet according to claim 1 or 2. The surface roughness (Ra) of the surface of the porous sheet on the side where the double-sided adhesive sheet is not arranged is 16 μm or less.
The laminated porous sintered sheet according to any one of claims 1 to 3. The area ratio of the opening of the through hole to the total area of the double-sided adhesive sheet is 40% or more.
The laminated porous sintered sheet according to any one of claims 1 to 4. The porous sheet contains a polyethylene resin,
The laminated porous sintered sheet according to any one of claims 1 to 5. The viscosity average molecular weight Mv of the polyethylene resin is 1.0 × ¹⁰⁵ or more.
The laminated porous sintered sheet according to claim 6. Adsorption fixed transport sheet,
The laminated porous sintered sheet according to any one of claims 1 to 7.

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