JP6466780B2 - Manufacturing method of resin sheet for nailing - Google Patents

Description

  The present invention relates to a nailing resin sheet and a method for producing the same.

In a ball game machine, nails for changing the falling direction of the game ball are driven into a plurality of holes (usually through holes) formed by NC (numerical control machining) processing or the like on the game board.
At present, veneer plywood is the mainstream of game board materials used in ball game machines.
In recent years, in order to enhance the entertainment characteristics of ball game machines, a configuration in which a transparent resin sheet is used as a material for the game board and a lighting panel such as a liquid crystal display panel and / or an LED (light emitting diode) is combined. (Patent Documents 1 to 3 etc.).

Examples of the transparent resin include carbonate resins and methacrylic resins.
Since the carbonate-based resin sheet has a relatively low surface hardness, the carbonate-based resin sheet tends to be easily damaged by friction with the game ball or collision of the game ball.
Since the methacrylic resin sheet has a relatively high surface hardness, it is difficult to be damaged even by friction with the game ball or collision of the game ball. However, general methacrylic resins have insufficient impact resistance, and there is a risk of resin cracking when nailing. Therefore, Patent Documents 4 and 5 disclose a nailing resin sheet that has improved impact resistance by adding acrylic rubber particles to a methacrylic resin in order to suppress resin cracking during nailing. (Claim 1 of Patent Document 4 and Claim 1 of Patent Document 5).

JP 2000-061047 A JP 07-000614 A JP 2005-034606 JP 2006-320705 A JP 2008-049137 A

In a conventional nailing resin sheet, nailing or bending may occur when nailing or after nailing, or the nail may loosen or come off after nailing.
Further, the sheet may be warped after nailing, and the nail may be removed or the position of the nail may be changed.
Although the addition of acrylic rubber particles can improve the impact resistance of the resin sheet and suppress resin cracking during nailing, it does not act effectively on the above problems.

  The present invention has been made in view of the above circumstances, and nail breakage and nail bending at the time of nailing or after nailing, nail loosening and nail omission after nailing, warping of a sheet and nail omission and nail by this An object of the present invention is to provide a nailing resin sheet capable of suppressing a change in position of the nail and a method for manufacturing the same.

The resin sheet for nailing of the present invention is
It consists of a resin composition containing a methacrylic resin (A) and an acrylic rubber (B) as the main components,
The acrylic rubber (B) content in the resin composition is 15% by mass or more,
The thickness is 5 mm or more,
When viewed in the thickness direction, the maximum absolute value of the internal residual stress excluding the surface layer portion and the back layer portion is 100 kg / cm ² or less.
This is a resin sheet for nailing.

  In the present specification, the internal residual stress excluding the surface layer portion and the back layer portion is also referred to as “internal residual stress”.

The manufacturing method of the resin sheet for nailing of the present invention,
A method for producing the above-described nail-forming resin sheet of the present invention,
Extruding means for heating and melting the resin composition and extruding it into a sheet,
A cooling roll unit composed of a plurality of cooling rolls arranged adjacent to each other and cooled while pressurizing the sheet-like material extruded by the extrusion molding means;
Using a manufacturing apparatus provided with a pair of take-up rolls that are arranged to face each other and express the force of taking up the manufactured resin sheet,
Adjusting the overall temperature of the resin sheet within a range of 115 to 165 ° C. at the time of leaving the cooling roll on the most downstream side of the plurality of cooling rolls of the cooling roll unit;
Among the plurality of cooling rolls of the cooling roll unit, when the peripheral speed of the second cooling roll located second from the upstream side is V2, and the peripheral speed of the pair of take-up rolls is VX,
Adjusting the ratio (VX / V2) of the peripheral speed VX of the pair of take-up rolls to the peripheral speed V2 of the second cooling roll within a range of 0.98 to 1.01;
Between the cooling roll unit and the pair of take-up rolls, the resin sheet is gradually cooled by passing through an environment adjusted in a range of 5 to 50 ° C.

In the present specification, the “main component” is defined as a component exceeding 50 mass%.
In this specification, the “sheet” is a plate-like object having no flexibility.
In this specification, the “front surface” of the nail driving resin sheet is the sheet surface on the side where the nail is driven, and the “back surface” is the sheet surface on the opposite side. Before hitting the nail, the front surface is one sheet surface, the back surface is the other sheet surface, and “front surface” and “back surface” are not clearly distinguished.
The “surface layer portion” refers to a portion from the surface to a depth of 10 μm. Similarly, the “back layer portion” refers to a portion from the back surface to a depth of 10 μm.

In this specification, unless otherwise specified, “the internal residual stress at an arbitrary in-plane position of the sheet”, “the maximum absolute value εa of the internal residual stress of the sheet”, and “the residual stress of the surface layer portion of the sheet and the back layer portion” The “maximum absolute value of the difference from the residual stress (εb)” is measured by the following method.
The resin sheet is cut in the thickness direction to obtain a strip-shaped sample having a width of 0.1 cm. In this case, in the case of an extruded resin plate, the cut surface is set to be perpendicular to the sheet extrusion direction.
Using a precision strain meter “SVP30” manufactured by Toshiba Corporation, the strain at the surface layer portion and the center portion at a certain arbitrary position is measured on the cut surface of the sample.
Specifically, with respect to the strain zero standard line of the strain gauge, the refractive distance difference X of the strain between the surface layer portion and the central portion at a certain arbitrary position is measured on the cut surface of the sample. As the internal residual stress, the internal stress F is obtained based on the following equation using the obtained data.
In the strip-shaped sample, the above measurement is performed at random at two or more locations on the entire cut surface to obtain the maximum absolute value εa of the internal residual stress.

F = XR / CL
(In the above formula, each abbreviation shows the following parameters.)
F: Internal stress [kg / cm ² ],
X: Refraction distance difference [cm]
R: apparatus coefficient [nm / cm] (62.6 nm / cm in the apparatus used by the present inventors),
C: Photoelastic constant [(nm / cm) / (kg / cm ² )] (in the case of a methacrylic resin composition, 3.8 [(nm / cm) / (kg / cm ² ))],
L: Sample thickness [cm])

  In the strip-shaped sample, five or more virtual straight lines are drawn in the thickness direction at equal intervals over the entire cut surface, and the residual stress of the surface layer portion and the back layer portion on each virtual straight line is obtained by the same measurement as described above. The absolute value of the difference is calculated. Of the absolute values of the differences obtained 5 or more, the largest value is taken as the maximum absolute value (εb) of the difference between the residual stress of the surface layer portion and the back layer portion of the sheet.

In this specification, “weight average molecular weight (Mw) and number average molecular weight (Mn)” are values obtained by converting a chromatogram measured by gel permeation chromatography (GPC) into a molecular weight of standard polystyrene.
In the present specification, the “molecular weight distribution” is defined by the ratio between the weight average molecular weight (Mw) and the number average molecular weight (Mn), that is, Mw / Mn.
In the present specification, the content of a component having a molecular weight of 200,000 or more (defined as “high molecular weight component”) is the molecular weight of 200,000 in the area surrounded by the chromatogram and the baseline measured by GPC. Calculated as the ratio of the area of the retention time portion earlier than the retention time of standard polystyrene.
The content of a component having a molecular weight of less than 15000 (defined as “low molecular weight component”) is based on the retention time of standard polystyrene having a molecular weight of 15000 in the area surrounded by the chromatogram obtained by GPC and the baseline. Calculated as a percentage of the area of the slow holding time portion.

Specifically, the weight average molecular weight (Mw), the molecular weight distribution (Mw / Mn), the content of the high molecular weight component and the low molecular weight component are measured by the following methods.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) are calculated by measuring chromatograms under the following conditions by gel permeation chromatography (GPC) and converting them to the molecular weight of standard polystyrene.
“HLC-8320” manufactured by Tosoh Corporation was used as the GPC apparatus. A differential refractive index detector (RI detector) is used as the detector. As the column, a column in which two “TSKgel Super Multipore HZM-M” manufactured by Tosoh Corporation and “Super HZ4000” are connected in series is used. Tetrahydrofuran (THF) is used as the eluent. A solution obtained by dissolving 4 mg of resin in 5 ml of tetrahydrofuran is used as a measurement sample. The eluent flow rate is 0.35 ml / min. The column temperature is 40 ° C. A chromatogram is measured by injecting 20 μl of sample solution at an eluent flow rate of 0.35 ml / min.
The baseline of the chromatogram shows that the slope of the peak on the high molecular weight side of the GPC chart changes from zero to positive when viewed from the earlier retention time, and the slope of the peak on the lower molecular weight side is viewed from the earlier retention time. The line connecting points that change from minus to zero. If the chromatogram shows multiple peaks, connect the line connecting the point where the slope of the highest molecular weight peak changes from zero to positive and the point where the slope of the lowest molecular weight peak changes from negative to zero. Baseline.
From the integrated molecular weight distribution calculated using the calibration curve, the ratio of components having a molecular weight of 200,000 or more (high molecular weight components) and the ratio of components having a molecular weight of less than 15,000 (low molecular weight components) are calculated.
GPC measurement is performed using standard polystyrene having a molecular weight in the range of 400 to 5000000, and a calibration curve indicating the relationship between the retention time and the molecular weight is created. A calibration curve is prepared using 10 standard polystyrene data.

In this specification, unless otherwise specified, the “glass transition temperature (Tg)” is an intermediate glass transition temperature measured by the following method.
Using a differential scanning calorimeter (“DSC-50” manufactured by Shimadzu Corporation), the temperature of the sample was once raised to 230 ° C. and cooled to room temperature, and then increased again from room temperature to 230 ° C. at a rate of 10 ° C./min. The DSC curve is measured under the condition of raising the temperature at. An intermediate point obtained from the obtained DSC curve is defined as a glass transition temperature (Tg). When a plurality of shoulders appear in the DSC curve, the glass transition temperature (Tg) is determined based on the highest temperature side shoulder.

  According to the present invention, it is possible to suppress nail breaking and nail bending at the time of nail driving or after nail driving, nail loosening and nail omission after nail driving, sheet warping and nail omission and nail position change due to this. A possible nailing resin sheet and a method for producing the same can be provided.

It is a schematic diagram which shows the manufacturing apparatus of the resin sheet for nailing of one Embodiment which concerns on this invention.

"Plastic sheet for nailing"
The present invention relates to a nailing resin sheet (hereinafter sometimes simply referred to as “resin sheet”).
The nail driving application is not particularly limited, and examples thereof include a ball game machine.
In a ball game machine, nails for changing the falling direction of the game ball are driven into a plurality of holes (usually through holes) formed by NC (numerical control machining) processing or the like on the game board.
Other nailing applications include building materials such as resin sashes and joint materials.

The resin sheet for nailing of the present invention comprises a resin composition (C) containing a methacrylic resin (A) and an acrylic rubber (B) as main components.
Hereinafter, the nailing resin sheet of the present invention may be simply abbreviated as “resin sheet” or “sheet”.

Even under a temperature environment of 40 ° C. or higher, warping of the sheet and nail removal or change in the position of the nail are effectively suppressed. Therefore, the resin sheet for nailing of the present invention has a thickness t of 5 mm or more. is there.
If the thickness t is less than 5 mm, the sheet is likely to warp, particularly under a temperature environment of 40 ° C. or more, and this tends to cause nail removal or nail position change.
The upper limit of the thickness t is not particularly limited, and is about 70 mm from the sheet formability.

In applications such as a ball game machine, the thickness t of the resin sheet for nailing of the present invention is preferably 5 to 30 mm, more preferably 5 to 20 mm.
In applications such as ball game machines, if the thickness t is less than 5 mm, the sheet tends to warp, particularly under a temperature environment of 40 ° C. or higher, and this tends to cause nail removal or nail position change. If the thickness t exceeds 30 mm, the sheet becomes heavy and the handling property tends to be lowered.

In the nailing resin sheet of the present invention, the maximum absolute value εa of internal residual stress (internal residual stress) excluding the surface layer portion and the back layer portion is 100 kg / cm ² or less as viewed in the thickness direction.

The nailing resin sheet is manufactured by a known molding method such as an extrusion molding method, a cast molding method, and an injection molding method.
Depending on the manufacturing method and manufacturing conditions, residual stress may remain inside the manufactured nailing resin sheet. The internal residual stress is compressive stress and / or tensile stress, and can be released by applying heat.

For example, when a hole for nailing (usually a through hole) is formed in a nailing resin sheet having an internal residual stress, the internal residual stress is released by processing heat, and the diameter of the formed hole is reduced from a desired diameter. There is a risk of shifting.
When the internal residual stress is a compressive stress, the diameter of the hole to be formed becomes smaller than the desired diameter, and there is a possibility that nail breaking or nail bending may occur during or after nail driving.
When the internal residual stress is a tensile stress, the diameter of the hole to be formed becomes larger than the desired diameter, and the driven nail may be loosened or pulled out.

In addition, as described in the “Background Art” section, in recent years, ball game machines have a configuration in which a transparent resin sheet is combined with a display panel such as a liquid crystal display panel and / or an illumination device such as an LED (light emitting diode). It is being considered. In such a configuration, the resin sheet for nailing can be exposed to a temperature of 40 ° C. or higher by heat generated from a backlight of a liquid crystal display panel or an LED (light emitting diode). When a nailing resin sheet having internal residual stress is exposed to such a temperature, the internal residual stress can be released.
When the internal residual stress is a compressive stress, the nail breakage or the nail bending may occur, and when the internal residual stress is a tensile stress, the nail may be loosened or pulled out.

When viewed in the thickness direction, the maximum absolute value εa of the internal residual stress of the resin sheet for nailing is set to 100 kg / cm ² or less, so that the nail breaks and bends during nailing or after nailing, and nailing. Later nail loosening and nail removal can be suppressed.
Note that a-(minus) value residual stress corresponds to a compressive stress, and a + (plus) value residual stress corresponds to a tensile stress.
When the maximum absolute value εa of the internal residual stress is less than −100 kg / cm ² , the internal compressive stress is large, and there is a risk that nail breaking or nail bending may occur during or after nail driving.
When the maximum absolute value εa of the internal residual stress exceeds +100 kg / cm ² , the internal tensile stress is large, and there is a possibility that the nail loosens or the nail comes off after nailing.

Nail breakage and nail bending, as well as nail loosening and nailing, can also occur due to various dimensional change factors other than internal residual stress.
Dimensional change factors other than the internal residual stress include the environmental temperature at the time of processing such as drilling of the nail-forming resin sheet, the water content of the nail-setting resin sheet, and the like.
Considering these dimensional change factors other than the internal residual stress, it is preferable to reduce the internal residual stress as much as possible and suppress the dimensional change caused by the internal residual stress as much as possible.
Specifically, the maximum absolute value εa of the internal residual stress is preferably 60 kg / cm ² or less, more preferably 50 kg / cm ² or less.

In the nailing resin sheet of the present invention,
When viewed in the thickness direction, the maximum absolute value εb of the difference between the residual stress in the surface layer portion and the residual stress in the back layer portion is preferably 80 kg / cm ² or less.
As described above, the nailing resin sheet can be exposed to a temperature of 40 ° C. or higher by heat generated from a backlight of a liquid crystal display panel or an LED (light emitting diode).
When the difference between the residual stress in the surface layer portion and the residual stress in the back layer portion is large, exposure to the above temperature releases the residual stress in the surface layer portion and the residual stress in the back layer portion, causing the sheet to warp. There is a risk of nail dropout or nail position change.
When the maximum absolute value εb of the difference between the residual stress in the surface layer portion and the residual stress in the back layer portion is set to 80 kg / cm ² or less as viewed in the thickness direction, the warp of the sheet and the position of the nail removal or nail caused thereby Change can be suppressed.

The warp of the sheet and the resulting nail drop or nail position change can also occur due to a difference in front and back, other than the difference in residual stress between the front and back. Examples of warping factors other than the residual stress difference between the front and back surfaces include a difference in moisture content between the front and back surfaces of the nailing resin sheet.
In consideration of warp factors other than the residual stress difference between the front and back surfaces, it is preferable to reduce the residual stress difference between the front and back surfaces as much as possible and to suppress the warp of the sheet due to the residual stress difference between the front and back surfaces as much as possible.
Specifically, when viewed in the thickness direction, the maximum absolute value εb of the difference between the residual stress in the surface layer portion and the residual stress in the back layer portion is more preferably 70 kg / cm ² or less, and particularly preferably 50 kg / cm ^2. It is as follows.

The nailing resin sheet is manufactured using a known sheet molding method such as an extrusion molding method, a cast molding method, and an injection molding method.
By devising the production method and production conditions, the maximum absolute value εa of the internal residual stress can be adjusted to 100 kg / cm ² or less, preferably 60 kg / cm ² or less, more preferably 50 kg / cm ² or less.
Further, by devising the production method and production conditions, the maximum absolute value εb of the difference between the residual stress of the surface layer portion and the residual stress of the back layer portion as viewed in the thickness direction is preferably 80 kg / cm ² or less, More preferably, it can be adjusted to 70 kg / cm ² or less, particularly preferably 50 kg / cm ² or less.
The extrusion molding method is particularly preferable because the internal residual stress and the difference between the front and back residual stresses can be effectively reduced. Specific preferred manufacturing conditions will be described later.

"Resin composition (C)"
The resin composition (C) used for the nailing resin sheet contains a methacrylic resin (A) and an acrylic rubber (B) as main components.

(Methacrylic resin (A))
The methacrylic resin (A) is a resin containing at least one monomer unit derived from a methacrylic acid ester.
The methacrylic resin (A) preferably includes a monomer unit derived from methyl methacrylate (MMA).
In the methacrylic resin (A), the content of the monomer unit derived from methyl methacrylate (MMA) is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, particularly preferably 90. ˜100 mass%.
The methacrylic resin (A) can contain one or more monomer units in addition to the monomer unit derived from methyl methacrylate (MMA) as necessary.

Examples of other monomer units other than the monomer unit derived from methyl methacrylate (MMA) include:
(Meth) acrylic acid alkyl esters such as methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate;
(Meth) acrylic acid aryl esters such as phenyl (meth) acrylate;
(Meth) acrylic acid cycloalkyl esters such as cyclohexyl (meth) acrylate and norbornenyl (meth) acrylate;
and,
Monomer units derived from vinyl monomers having a polymerizable carbon-carbon double bond in one molecule such as (meth) acrylamide and (meth) acrylonitrile.

The methacrylic resin (A) preferably has a weight average molecular weight (Mw) of 50,000 to 300,000, more preferably 52,000 to 250,000, and particularly preferably 55,000 to 200,000.
The methacrylic resin (A) preferably has an average degree of polymerization of 500 to 3000, more preferably 520 to 2500, and particularly preferably 550 to 2000.
When the Mw and average degree of polymerization of the methacrylic resin (A) are in the above ranges, a mechanical property such as toughness and impact resistance is good, and a sheet having a uniform thickness and excellent surface smoothness is easily obtained.

The methacrylic resin (A) preferably has a molecular weight distribution (Mw / Mn) of 1.2 to 2.0, more preferably 1.3 to 1.7.
When the molecular weight distribution (Mw / Mn) is in the above range, a sheet having good mechanical properties such as toughness and impact resistance and excellent surface smoothness can be easily obtained.

In the methacrylic resin (A), the content of a component having a molecular weight of 200,000 or more (high molecular weight component) is preferably 0.1 to 10%, more preferably 0.5 to 5%.
In the methacrylic resin (A), the content of a component having a molecular weight of less than 15000 (low molecular weight component) is preferably 0.2 to 5%, more preferably 1 to 4.5%.
When the content of the high molecular weight component and the low molecular weight component of the methacrylic resin (A) is in the above range, molding processability is improved, and a sheet having a uniform thickness is easily obtained.

  From the viewpoint of moldability, the methacrylic resin (A) has a melt flow rate (MFR) measured at 230 ° C. under a load of 3.8 kg in accordance with JIS K 7210, preferably 0.1 g / It is 10 minutes or more, more preferably 0.1 to 30 g / 10 minutes, particularly preferably 0.5 to 20 g / 10 minutes, and most preferably 1.0 to 10 g / 10 minutes.

From the viewpoint of moldability, the glass transition temperature (Tg) of the methacrylic resin (A) is preferably 100 ° C. or higher. The upper limit of the glass transition temperature (Tg) of the methacrylic resin (A) is usually 130 ° C. or lower.
The glass transition temperature (Tg) can be controlled by adjusting the molecular weight or the like.

The production method of the methacrylic resin (A) is not particularly limited, and a known polymerization method such as a radical polymerization method or an anionic polymerization method can be applied.
Solvent-free continuous radical polymerization and anionic polymerization methods are preferred from the viewpoint of obtaining a methacrylic resin having high heat decomposability, little foreign matter, and high transparency.
In the above known polymerization method, by adjusting the polymerization temperature, the polymerization time, the type or amount of the chain transfer agent, or the type or amount of the polymerization initiator, the Mw, the ratio of the high molecular weight component, and the low molecular weight component A methacrylic resin (A) having characteristics such as a ratio within a desired range can be produced.

(Acrylic rubber (B))
The acrylic rubber (B) can improve the impact resistance of the resin sheet for nailing and suppress the resin cracking during nailing.
The acrylic rubber (B) is not particularly limited, and examples thereof include multilayer structure particles (BX) including at least one rubber layer, and a block copolymer (BY).
It is preferable that the acrylic rubber (B) contains the multilayer structure particles (BX) since the effect of improving the impact resistance can be effectively obtained.

<Multilayer structure particles (BX)>
The multilayer structure particle (BX) including at least one rubber layer is an acrylic rubber particle having a so-called core-shell structure including a soft layer (rubber layer) and a hard layer.

If the addition amount of the multilayer structure polymer (BX) is too small, the effect of improving the impact resistance cannot be obtained effectively, and there is a possibility that a resin crack occurs when nailing.
If the addition amount of the multilayer structure polymer (BX) is excessive, the haze value, surface smoothness and surface hardness of the resin sheet may be lowered.
The effect of improving impact resistance is effectively obtained, and the haze value, surface smoothness and surface hardness of the resin sheet are improved, so the inclusion of the multilayer structure polymer (BX) in the resin composition (C) The amount C is preferably 15% by mass or more, more preferably 15 to 45% by mass, further preferably 15 to 30% by mass, further preferably 20 to 30% by mass, and particularly preferably 20 to 20% by mass. 25% by mass.

In the present specification, unless otherwise specified, the content of the multilayer structure polymer (BX) is measured as follows.
One piece of the resin sheet is sufficiently dried to remove moisture, and then its mass (W1) is measured.
Next, the said sheet piece is put into a test tube, acetone is added and melt | dissolved, and an acetone soluble part is removed.
Then, acetone is removed using a vacuum heat dryer, and the mass (W2) of the residue is measured.
Based on the following formula, the content of the multilayer polymer (BX) is determined.
[Content of Multilayer Structure Polymer (BX)] = (W2 / W1) × 100 (%)

  In addition, when the outermost layer of a multilayer structure polymer (BX) melt | dissolves in acetone, the compounding quantity of a multilayer structure polymer (BX) and content calculated | required by the said measurement may not correspond. However, in the present specification, the content of the multilayer polymer (BX) is determined on the assumption that the acetone-insoluble portion is a rubber component contributing to impact resistance.

When the particle size of the multilayer structure polymer (BX) in the sheet is too small, the effect of improving the impact resistance cannot be obtained effectively, and there is a possibility that a resin crack occurs when nailing.
If the particle size of the multilayer structure polymer (BX) in the sheet is excessive, especially when the amount of the multilayer structure polymer (BX) added is large, the driven nail tends to come off easily.
Since the effect of improving impact resistance is effectively obtained and nail removal is suppressed, the particle size of the multilayer structure polymer (BX) in the sheet is preferably 0.05 to 0.3 μm.

In this specification, the particle diameter of the polymer particles in the latex containing the polymer particles is measured using a light scattering photometer DLS-600 manufactured by Otsuka Electronics Co., Ltd. unless otherwise specified.
The average particle diameter in the latex of the polymer particles is determined by measuring by a dynamic light scattering method using a sample collected from the latex after the completion of polymerization, and analyzing by a cumulant method.

In the course of sheet production, the non-crosslinked outermost layer of the multilayer structure polymer (BX) may melt to form a matrix. In this case, the particle diameter of the multilayer structure polymer (BX) in the sheet is smaller than the particle diameter of the raw polymer particles.
In the present specification, the particle size of the multilayer structure polymer (BX) in the sheet is determined by cross-sectional observation with a transmission electron microscope (TEM) unless otherwise specified.
Specifically, a part of the resin sheet is cut out, cut in the thickness direction with a microtome under freezing conditions, the obtained section is dyed with ruthenic acid, and the cross section of the dyed rubber particles is observed with a TEM. . The average value of 100 particles is defined as the average particle size.

As a multilayer structure polymer (BX),
The outermost layer is a hard layer containing 40 to 100% by mass of at least one methacrylate unit and 0 to 60% by mass of another monomer unit that can be copolymerized as necessary,
At least one inner layer (layer inside the outermost layer) is at least one acrylate unit unit of 40 to 99.9% by mass, and, if necessary, other monomer units of 0 to 60% by mass, And the multilayer structure polymer (BX-1) which is a soft layer (rubber layer) containing 0.1-5 mass% of polyfunctional monomer units is preferable.

  In the present specification, the “polyfunctional monomer” is a crosslinking agent (crosslinkable monomer) containing two or more polymerizable functional groups.

  From the viewpoint of heat resistance, the hard layer constituting the outermost layer of the multilayer structure polymer (BX-1) has a glass transition temperature (Tg) of 25 ° C. or higher when formed alone. Is preferred. In addition, at least one inner layer is composed of a soft layer (rubber layer), and from the viewpoint of impact resistance, the glass transition temperature (Tg) when the soft layer is formed alone may be less than 25 ° C. preferable.

  The ratio of the outermost layer in the acrylic multilayer structure particles (BX-1) is not particularly limited, but in order to ensure good dispersibility during melt kneading with the methacrylic resin (A), 10 to 80 masses. % Is preferably in the range of%.

  As a monomer for the hard layer of the acrylic multilayer structure particle (BX-1), from the viewpoint of transparency, a methacrylic acid ester is used. Examples thereof include methyl methacrylate, ethyl methacrylate, butyl methacrylate, Examples include benzyl methacrylate and cyclohexyl methacrylate. These can be used alone or in combination of two or more. The methacrylic acid ester used for the hard layer preferably contains methyl methacrylate.

If necessary, a polyfunctional monomer that is a copolymerizable unsaturated monomer and / or a crosslinking agent can be used for the hard layer according to the methacrylic acid ester.
As an unsaturated monomer that can be copolymerized,
Acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, and benzyl acrylate;
Aromatic vinyl compounds such as styrene, vinyltoluene, and α-methylstyrene;
N-substituted maleimide compounds such as N-cyclohexylmaleimide, N-o-chlorophenylmaleimide, and N-tert-butylmaleimide;
And vinyl cyanide compounds such as (meth) acrylonitrile.
These can be used alone or in combination of two or more.

As a polyfunctional monomer,
Allyl (meth) acrylate, triallyl cyanurate, allyl cinnamate, allyl sorbate, diallyl maleate, diallyl phthalate, triallyl trimellitic acid, diallyl fumarate, ethylene glycol di (meth) acrylate, polyethylene glycol di ( And (meth) acrylate, divinylbenzene, and 1,3-butylene glycol di (meth) acrylate.
These can be used alone or in combination of two or more.

  As a monomer for the soft layer (rubber layer) of the acrylic multilayer structure particles (BX-1), from the viewpoint of impact resistance, an acrylate ester and other monomers copolymerizable as necessary , And polyfunctional monomers are used.

Examples of the acrylate ester include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, and benzyl acrylate.
These can be used alone or in combination of two or more.
The acrylate ester used for the soft layer (rubber layer) preferably contains butyl acrylate and / or 2-ethylhexyl acrylate.

As other monomers copolymerizable with acrylic ester,
Diene compounds such as 1,3-butadiene, 2,3-dimethylbutadiene, and isoprene;
Aromatic vinyl compounds such as styrene, vinyltoluene, and α-methylstyrene;
Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, benzyl methacrylate, and cyclohexyl methacrylate;
And vinyl cyanide compounds such as (meth) acrylonitrile.
These can be used alone or in combination of two or more.

Polyfunctional monomers include allyl (meth) acrylate, triallyl cyanurate, allyl cinnamate, allyl sorbate, diallyl maleate, diallyl phthalate, triallyl trimellitic acid, diallyl fumarate, ethylene glycol di ( (Meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, divinylbenzene, and 1,3-butylene glycol di ( And (meth) acrylate.
These can be used alone or in combination of two or more.

  The multilayer structure of the acrylic multilayer structure particles (BX-1) is optional as long as the outermost layer is a hard layer and at least one inner layer is a soft layer. As the multi-layer structure, from the inner layer toward the outer layer, a two-layer structure of soft layer-hard layer, three-layer structure of hard layer-soft layer-hard layer, soft layer-hard layer-soft layer-hard Examples thereof include a four-layer structure of layers and a four-layer structure of hard layer-soft layer-soft layer-hard layer.

The acrylic multilayer structure particles (BX-1) can be produced by a known emulsion polymerization method.
First, one or two or more kinds of raw material monomers are emulsion-polymerized to form core particles, and then one or two or more other monomers are emulsion-polymerized in the presence of the core particles to form core particles. Form a shell around. Next, if necessary, one or more monomers are further emulsion-polymerized in the presence of particles consisting of a core and a shell to form another shell. By repeating such a polymerization reaction, the intended acrylic multilayer structure particles (BX-1) can be produced as an emulsified latex.

A known surfactant can be used for the emulsion polymerization. The surfactant can be selected according to the purpose from the viewpoint of the stability of the polymerization system and the particle diameter of the produced acrylic multilayer structure particles.
Examples of the surfactant include an anionic surfactant, a cationic surfactant, and a nonionic surfactant, and an anionic surfactant is preferable.
These surfactants can be used alone or in combination of two or more.

As an anionic surfactant,
Carboxylates such as sodium stearate, sodium myristate, and sodium N-lauroyl sarcosine;
Sulfonates such as sodium dioctylsulfosuccinate and sodium dodecylbenzenesulfonate;
Sulfate esters such as sodium lauryl sulfate;
Examples thereof include phosphate esters such as sodium mono-n-butylphenylpentaoxyethylene phosphate.

The polymerization initiator used for emulsion polymerization is not particularly limited,
Inorganic peroxides such as potassium persulfate and ammonium persulfate;
Water-soluble redox initiators such as hydrogen peroxide-ferrous salt, potassium persulfate-acid sodium sulfite, and ammonium persulfate-acid sodium sulfite;
Examples thereof include water-oil-soluble redox initiators such as cumene hydroperoxide-sodium formaldehyde sulfoxylate and tert-butyl hydroperoxide-sodium formaldehyde sulfoxylate.

A chain transfer agent can be used for emulsion polymerization as needed.
Examples of the chain transfer agent include alkyl mercaptans such as n-dodecyl mercaptan, n-lauryl mercaptan, tert-dodecyl mercaptan, and sec-butyl mercaptan.

  In the emulsion polymerization of each layer, the addition of monomers, emulsifiers, polymerization initiators, chain transfer agents and other raw materials to the polymerization reaction system may be any known method such as a batch addition method, a split addition method, and a continuous addition method. It can be done by the method.

  The polymerization reaction temperature of each layer is preferably 30 to 120 ° C, more preferably 50 to 100 ° C. The polymerization reaction time for each layer varies depending on the types and amounts of polymerization initiators and emulsifiers used, and the polymerization temperature, but is usually 0.5 to 7 hours for each layer. The mass ratio of monomer to water (monomer / water) is preferably 1/20 to 1/1.

The acrylic multilayer structure particles (BX-1) contained in the polymer latex obtained by emulsion polymerization are granular. The particle diameter is preferably 0.05 to 0.3 μm.
Latex containing acrylic multilayer structure particles (BX-1) can be used for the production of the sheet.
Acrylic multilayer structure particle (BX-1) is a powdered polymer by coagulation, dehydration, drying, etc. by a known method with respect to a polymer latex produced by emulsion polymerization, if necessary. Can be recovered.

(Block copolymer (BY))
The block copolymer (BY) is not particularly limited, and a block copolymer (BY-1) including a methacrylic ester polymer block (b1) and an acrylate polymer block (b2) is preferable.
The number of the methacrylic ester polymer block (b1) in the block copolymer (BY) is not particularly limited, and may be singular or plural.
Similarly, the number of acrylic ester polymer blocks (b2) in the block copolymer (BY) is not particularly limited, and may be one or more.
The acrylic rubber (B) can contain one or more block copolymers (BY).

The methacrylic ester polymer block (b1) is a polymer block containing a structural unit (methacrylic ester unit) derived from a methacrylic ester.
The ratio of the methacrylic acid ester unit in the methacrylic acid ester polymer block (b1) is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably 98% by mass or more. is there.

The methacrylic acid ester is not particularly limited.
For example, methyl methacrylate (MMA), ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, methacryl Isoamyl acid, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, dodecyl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, 2-hydroxyethyl methacrylate , 2-methoxyethyl methacrylate, glycidyl methacrylate, and allyl methacrylate.
These methacrylic acid esters can form a methacrylic acid ester polymer block (b1) by polymerizing alone or in combination of two or more.
Among the above methacrylic acid esters, from the viewpoint of improving transparency and heat resistance, methyl methacrylate (MMA), ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, And alkyl methacrylates such as isobornyl methacrylate are preferred, and methyl methacrylate (MMA) is particularly preferred.

The methacrylic acid ester polymer block (b1) may contain a structural unit derived from a monomer other than the methacrylic acid ester.
The proportion of structural units derived from monomers other than methacrylate ester contained in the methacrylate polymer block (b1) is preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass. Hereinafter, the range is particularly preferably 2% by mass or less.

The monomer other than methacrylic acid ester is not particularly limited.
For example, acrylic ester, unsaturated carboxylic acid, aromatic vinyl compound, olefin, conjugated diene, (meth) acrylonitrile, (meth) acrylamide, vinyl acetate, vinyl pyridine, vinyl ketone, vinyl chloride, vinylidene chloride, and vinylidene fluoride Is mentioned.
These monomers other than methacrylic acid ester can form a methacrylic acid ester polymer block (b1) by copolymerizing together with the above-mentioned methacrylic acid ester alone or in combination of two or more.

The methacrylic acid ester polymer block (b1) is preferably composed of a polymer having a refractive index (n _23D ) in the range of 1.485 to 1.495. Thereby, the transparency of the resin composition (C) can be improved.

In this specification, “refractive index (n _23D )” means a value measured at a measurement wavelength of 587.6 nm (d-line) in an environment of relative humidity (RH) 50% and 23 ° C.

The weight average molecular weight Mw (b1) of the methacrylic acid ester polymer block (b1) is preferably 5000 to 150,000, more preferably 8000 to 120,000, and particularly preferably 12,000 to 100,000.
In addition, when a plurality of methacrylate polymer blocks (b1) are included in the block copolymer (BY), the above weight average molecular weight Mw (b1) is the same for all methacrylate polymer blocks (b1). The weight average molecular weight is calculated and defined as the sum of the numerical values.

  When the block copolymer (BY) contains a plurality of methacrylate polymer blocks (b1), the composition and molecular weight of the structural units constituting each methacrylate polymer block (b1) may be the same or non-identical. Good.

The weight average molecular weight (Mw) of the methacrylic resin (A) is defined as “Mw (A)”.
In the resin composition (C), Mw (A) / Mw (b1) is preferably 0.5 to 5.0, more preferably 1.0 to 4.0, and particularly preferably 1.2 to 3.0. is there.
If Mw (A) / Mw (b1) is too small, the impact resistance of the nailing resin sheet tends to decrease.
On the other hand, if Mw (A) / Mw (b1) is excessive, the surface smoothness and transparency of the nailing resin sheet tend to deteriorate.
When Mw (A) / Mw (b1) is within the above range, the dispersed particle diameter of the block copolymer (BY) in the resin sheet for nailing is sufficiently small, and the surface smoothness and transparency are good. It becomes.

  In addition, the weight average molecular weight (Mw) of each block of the methacrylic acid ester polymer block (b1) and the acrylic acid ester polymer block (b2) is an intermediate product and final product in the production process of the block copolymer (BY). It is calculated from the weight average molecular weight (Mw) of the block copolymer (BY) which is a product.

From the viewpoint of transparency, flexibility, molding processability, surface smoothness, and the like, the ratio of the methacrylic ester polymer block (b1) in the block copolymer (BY) is 10 to 80% by mass, preferably 20 to 20%. It is 70 mass%, More preferably, it is 40-60 mass%.
When the proportion of the methacrylic acid ester polymer block (b1) in the block copolymer (BY) is within the above range, the nail driving resin sheet becomes excellent in transparency and impact resistance.

The acrylic ester polymer block (b2) is a polymer block containing a structural unit (acrylic ester unit) derived from an acrylic ester.
The ratio of the acrylate ester unit in the acrylate polymer block (b2) is preferably 45% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, and particularly preferably 90% by mass or more. .

Examples of the acrylic ester include
Methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, acrylic acid n-hexyl, cyclohexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, isobornyl acrylate, phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-acrylate Examples include methoxyethyl, glycidyl acrylate, and allyl acrylate.
An acrylic acid ester polymer block (b2) can be formed by polymerizing these acrylic acid esters alone or in combination of two or more.

  The acrylic ester polymer block (b2) may include a structural unit derived from a monomer other than the acrylic ester. The proportion of structural units derived from monomers other than the acrylate ester contained in the acrylate polymer block (b2) is preferably 55% by mass or less, more preferably 50% by mass or less, and still more preferably 40% by mass. Hereinafter, it is particularly preferably 10% by mass or less.

As monomers other than acrylic esters, methacrylic esters, unsaturated carboxylic acids, aromatic vinyl compounds, olefins, conjugated dienes, (meth) acrylonitrile, (meth) acrylamides, vinyl acetate, vinyl pyridine, vinyl ketone, vinyl chloride , Vinylidene chloride, and vinylidene fluoride.
Monomers other than these acrylic esters can be used alone or in combination of two or more, and can be copolymerized with the above-mentioned acrylic ester to form the acrylic ester polymer block (b2).

  From the viewpoint of improving the transparency of the resin composition (C), the acrylate polymer block (b2) is a non-aromatic structural unit derived from an acrylate ester having no aromatic ring (non-aromatic). (Acrylic acid ester unit) and an aromatic structural unit derived from a (meth) acrylic acid ester having an aromatic ring (aromatic (meth) acrylic acid ester unit).

Examples of non-aromatic acrylic esters include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and dodecyl acrylate.
Of these, n-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable.

Aromatic (meth) acrylic acid esters are those in which an aromatic ring or a group containing it is ester-bonded to (meth) acrylic acid.
Examples of the aromatic (meth) acrylic acid ester include phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, and styryl (meth) acrylate.
Of these, phenyl methacrylate, benzyl (meth) acrylate, phenoxyethyl methacrylate, and the like are preferable.

  When the acrylic ester polymer block (b2) includes a non-aromatic acrylic ester unit and an aromatic (meth) acrylic ester unit, the acrylic ester polymer block (b2) is a non-aromatic acrylic ester unit. It preferably contains 50 to 90% by mass and 50 to 10% by mass of aromatic (meth) acrylate units, and 60 to 80% by mass of non-aromatic acrylate units and 40 units of aromatic (meth) acrylate units. More preferably, it contains ~ 20 mass%.

The acrylate polymer block (b2) is preferably composed of a polymer having a refractive index (n _23D ) in the range of 1.485 to 1.495. Thereby, the transparency of the nailing resin sheet can be improved.

The weight average molecular weight Mw (b2) of the acrylate polymer block (b2) is preferably 5,000 to 120,000, more preferably 15,000 to 110,000, and particularly preferably 30,000 to 100,000.
When the block copolymer (BY) includes a plurality of acrylate polymer blocks (b2), the weight average molecular weight Mw (b2) is the same for all acrylate polymer blocks (b2). Each weight average molecular weight is calculated and defined as the sum of the numerical values.

  When there are a plurality of acrylate polymer blocks (b2) in the block copolymer (BY), the composition and molecular weight of the structural units constituting each acrylate polymer block (b2) are the same or non-identical. Good.

  If Mw (b2) is too small, the impact resistance of the nailing resin sheet tends to decrease. On the other hand, if Mw (b2) is excessive, the surface smoothness and transparency of the nailing resin sheet tend to deteriorate.

From the viewpoint of transparency and surface smoothness, the proportion of the acrylate polymer block (b2) in the block copolymer (BY) is preferably 20 to 90 mass%, more preferably 30 to 80 mass%.
When the ratio of the acrylate polymer block (b2) in the block copolymer (BY) is within the above range, the nail driving resin sheet is excellent in impact resistance.

In the block copolymer (BY), the bonding form of the methacrylic ester polymer block (b1) and the acrylate polymer block (b2) is not particularly limited.
Examples of the bonding form include a structure in which a methacrylic ester polymer block (b1) and an acrylate polymer block (b2) are connected in series.
As a coupling form connected in series, for example,
A methacrylic acid ester polymer block (b1) having one end connected to one end of an acrylic acid ester polymer block (b2) (a diblock copolymer having a (b1)-(b2) structure);
A triblock copolymer having a (b2)-(b1)-(b2) structure in which one end of an acrylate polymer block (b2) is connected to each of both ends of a methacrylate polymer block (b1) );
And a acrylate polymer block (b2) having both ends connected to one end of a methacrylic acid ester polymer block (b1) (a triblock copolymer of (b1)-(b2)-(b1) structure) And the like).

As other coupling forms,
A block copolymer ([(b1)-(b2)-] nX structure) in which one end of a plurality of block copolymers having a (b1)-(b2) structure is connected to form a radial structure;
A block copolymer ([(b2)-(b1)-] nX structure) in which one end of a plurality of block copolymers having the structure (b2)-(b1) is connected to form a radial structure;
A block copolymer ([(b1)-(b2)-(b1)-] nX in which one terminal of a plurality of block copolymers having a structure (b1)-(b2)-(b1) is connected to form a radial structure) Construction);
And a block copolymer ([(b2)-(b1)-(b2)-] in which one end of a block copolymer having a plurality of (b2)-(b1)-(b2) structures is connected to form a radial structure. nX structure) and the like.

  Other bonding forms include block copolymers having a branched structure.

  Note that X in the description of the bonding form is a coupling agent residue.

  Of the above bonding forms, diblock copolymers, triblock copolymers, and star block copolymers are preferred, and (b1)-(b2) -structured diblock copolymers, (b1)-(b2) -(B1) structure triblock copolymer, [(b1)-(b2)-] nX structure star block copolymer, and [(b1)-(b2)-(b1)-] nX structure Star block copolymers are more preferred.

The block copolymer (BY) may have a polymer block (b3) other than the methacrylic acid ester polymer block (b1) and the acrylate polymer block (b2).
The main structural unit constituting the other polymer block (b3) is a structural unit derived from a monomer other than methacrylic acid ester and acrylic acid ester.
Examples of such monomers include:
Olefins such as ethylene, propylene, 1-butene, isobutylene, and 1-octene;
Conjugated dienes such as butadiene, isoprene, and myrcene;
Aromatic vinyl compounds such as styrene, α-methylstyrene, p-methylstyrene, and m-methylstyrene;
Examples include vinyl acetate, vinyl pyridine, acrylonitrile, methacrylonitrile, vinyl ketone, vinyl chloride, vinylidene chloride, vinylidene fluoride, acrylamide, methacrylamide, ε-caprolactone, and valerolactone.
These can be used alone or in combination of two or more.

The bonding form of the methacrylic ester polymer block (b1), the acrylate ester polymer block (b2), and the polymer block (b3) in the block copolymer (BY) is not particularly limited.
As the bonding form, for example, a block copolymer having a structure (b1)-(b2)-(b1)-(b3) and a structure (b3)-(b1)-(b2)-(b1)-(b3) The block copolymer etc. are mentioned.
When there are a plurality of polymer blocks (b3) in the block copolymer (BY), the composition and molecular weight of the structural units constituting each polymer block (b3) may be the same or non-identical.

  The block copolymer (BY) may have a functional group such as a hydroxyl group, a carboxyl group, an acid anhydride, and an amino group in the molecular chain or at the molecular chain terminal, if necessary.

Let the weight average molecular weight (Mw) of a block copolymer (BY) be "Mw (B)." Mw (B) is preferably 32000 to 300000, more preferably 45000 to 230,000.
When Mw (B) is too small, sufficient melt tension cannot be maintained in melt extrusion molding, and it is difficult to obtain a good nail-forming resin sheet, and mechanical properties such as the breaking strength of the obtained nail-forming resin sheet are poor. There is a tendency to decrease. On the other hand, when Mw (B) is excessive, the viscosity of the molten resin is increased, and the surface of the nailing resin sheet obtained by melt extrusion molding is caused by fine grainy unevenness or unmelted material (high molecular weight body). There is a tendency that it is difficult to obtain a good nail-forming resin sheet.

  The molecular weight distribution (Mw / Mn) of the block copolymer (BY) is preferably 1.0 to 2.0, more preferably 1.0 to 1.6. By having the molecular weight distribution (Mw / Mn) within such a range, the content of unmelted material that causes the occurrence of flaws in the nailing resin sheet can be made extremely small.

The refractive index (n _23D ) of the block copolymer (BY) is preferably from 1.485 to 1.495, more preferably from 1.487 to 1.493. When the refractive index (n _23D ) is within this range, the transparency of the nailing resin sheet can be improved.

The manufacturing method of a block copolymer (BY) is not specifically limited, A well-known method can be used.
For example, a method of living polymerizing monomers constituting each polymer block is preferable.
Examples of living polymerization methods include:
A method of anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of a mineral acid salt such as an alkali metal or alkaline earth metal salt;
A method of anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organic aluminum compound;
A method of polymerizing using an organic rare earth metal complex as a polymerization initiator;
and,
Examples include a method of radical polymerization using an α-halogenated ester compound as a polymerization initiator in the presence of a copper compound.
In addition, a method of producing a mixture containing a block copolymer (BY) by polymerizing monomers constituting each block using a polyvalent radical polymerization initiator or a polyvalent radical chain transfer agent is also included. .
Among these methods, in particular, the block copolymer (BY) is obtained with high purity, the molecular weight, the composition, etc. are easily controlled and economical, so an organic alkali metal compound is used as a polymerization initiator. A method in which anionic polymerization is used in the presence of an organoaluminum compound is preferred.

(Optional component)
The nailing resin sheet of the present invention can contain optional components other than those described above, if necessary.
The nailing resin sheet of the present invention can contain one or more other resins.
The nailing resin sheet of the present invention can contain one or more additives.

As other resins,
Olefin resins such as polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, and polynorbornene;
Ethylene ionomers;
Styrene resins such as polystyrene, styrene-maleic anhydride copolymer, high impact polystyrene, AS resin, ABS resin, AES resin, AAS resin, ACS resin, and MBS resin;
Ester resins such as polyethylene terephthalate and polybutylene terephthalate;
Amide resins such as nylon 6, nylon 66, and polyamide elastomer;
Halogen-containing resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and polyvinylidene fluoride;
Acetal resin;
Urethane resin;
Modified polyphenylene ether and polyphenylene sulfide;
Silicone modified resin;
Silicone rubber;
Styrenic thermoplastic elastomers such as SEPS, SEBS, and SIS;
And olefinic rubbers such as IR, EPR, and EPDM.

  The amount of other resin that can be contained in the nailing resin sheet of the present invention is preferably 10% by mass or less, more preferably 5% by mass or less, and most preferably 0% by mass.

  Additives include lubricants, UV absorbers, fillers, antioxidants, thermal degradation inhibitors, light stabilizers, mold release agents, polymer processing aids, antistatic agents, flame retardants, dyes and pigments, light diffusing agents, Organic dyes, matting agents, phosphors and the like can be mentioned.

(Lubricant)
In applications such as ball game machines, cutting processing for cutting a resin sheet into a predetermined shape using a saw or the like for a resin sheet for nailing, a hole for nailing and various game members using a drill, etc. A drilling process for opening a mounting hole and an outer shape process for adjusting the shape using a router or the like are performed.
The lubricant is a component that imparts lubricity to the resin sheet and lowers the coefficient of friction of the resin sheet. By adding this component, the resin sheet can be combined with the resin sheet by a lubricating effect in processing such as cutting or perforating the resin sheet. The frictional heat with the tool can be suppressed, and the deterioration of the appearance quality of the processed surface of the resin sheet and the resin fusion to the tool can be suppressed.

Examples of the lubricant include hydrocarbons, fatty acids, aliphatic alcohols, fatty acid esters, fatty acid amides, and metal soaps.
These can use 1 type (s) or 2 or more types.

  As the hydrocarbon used as a lubricant, an aliphatic hydrocarbon is preferable. Examples of the aliphatic hydrocarbon include liquid paraffin, microcrystalline wax, natural paraffin, synthetic paraffin, and polyolefin wax. Aliphatic hydrocarbons having an average carbon number of 12 or more are preferred. The hydrocarbon may be a partial oxide or halide of an aliphatic hydrocarbon.

As the fatty acid used as the lubricant, fatty acids having 12 or more carbon atoms such as lauric acid, palmitic acid, stearic acid, behenic acid, oleic acid, and erucic acid are preferable.
Among these, fatty acids having 16 to 24 carbon atoms such as palmitic acid, stearic acid, behenic acid, oleic acid, and erucic acid are more preferable, and saturation with 16 to 24 carbon atoms such as palmitic acid, stearic acid, and behenic acid. Fatty acids are particularly preferred.
As the fatty acid, a fatty acid having a hydroxyl group such as hydroxyl stearic acid is also preferred.
As fatty acid, what is contained in fats and oils, such as animal oil, vegetable oil, and mineral wax, may be used. Animal oils include beef tallow and fish oil. Examples of vegetable oils include coconut oil, soybean oil, rapeseed oil, and rice bran wax. Examples of the mineral wax include montan wax, ozokerite, ceresin, and oil shell.

The aliphatic alcohol used as a lubricant is preferably an aliphatic alcohol having 12 to 18 carbon atoms such as lauryl alcohol, palmityl alcohol, stearyl alcohol, and oleyl alcohol.
Among the above, C12-18 saturated aliphatic alcohols such as lauryl alcohol, palmityl alcohol, and stearyl alcohol are more preferable, and C16-18 saturated aliphatic alcohols such as palmityl alcohol, stearyl alcohol, and the like. Particularly preferred. Such aliphatic alcohols may be contained in the above-described oils and fats such as animal oils, vegetable oils, and mineral waxes.

The fatty acid ester used as a lubricant is preferably an ester (including a partial ester) of the fatty acid and a monovalent or polyvalent (divalent or higher) alcohol containing the aliphatic alcohol.
The fatty acid is preferably a saturated fatty acid, and the alcohol is preferably a saturated alcohol.
Examples of the alcohol include monohydric alcohols such as butanol, lauryl alcohol, palmityl alcohol, stearyl alcohol, behenyl alcohol, and oleyl alcohol; polyhydric alcohols such as ethylene glycol, glycerin, and sorbitol.
As fatty acid ester, the partial ester of the said fatty acid and the said polyhydric alcohol is preferable, and the fatty acid monoglyceride which is a partial ester of a C16-C22 fatty acid and glycerol is more preferable.

  Examples of fatty acid amides used as lubricants include amides and bisamides of the above fatty acids. Such fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxyl stearic acid amide, oleic acid amide, erucic acid amide, N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N -Stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide, methylene bis stearic acid amide, methylene bis capric acid amide, ethylene bis lauric acid amide, etc. are mentioned.

Examples of the metal soap used as the lubricant include alkaline earth metal salts or typical metal salts of the above fatty acids.
Examples of such metal soaps include barium stearate, calcium stearate, magnesium stearate, zinc stearate, and aluminum stearate.

The ultraviolet absorber is a compound having an ability to absorb ultraviolet rays. The ultraviolet absorber is a compound that is said to have a function of mainly converting light energy into heat energy.
Examples of the ultraviolet absorber include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, succinic anilides, malonic esters, and formamidines.
These can use 1 type (s) or 2 or more types.
Among these, benzotriazoles, triazines, or ultraviolet absorbers having a maximum molar extinction coefficient ε _{max at a} wavelength of 380 to 450 nm of 1200 dm ³ · mol ⁻¹ cm ⁻¹ or less are preferable.

Benzotriazoles are highly effective in suppressing deterioration of optical properties such as coloring due to ultraviolet irradiation.
As benzotriazoles,
2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (manufactured by BASF; trade name TINUVIN329),
2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (manufactured by BASF; trade name TINUVIN234),
and,
2,2′-methylenebis [6- (2H-benzotriazol-2-yl) -4-tert-octylphenol] (manufactured by ADEKA; LA-31) is preferred.

An ultraviolet absorber having a maximum molar extinction coefficient ε _{max at a} wavelength of 380 to 450 nm of 1200 dm ³ · mol ⁻¹ cm ⁻¹ or less can suppress yellowness of the resulting molded article. Examples of such an ultraviolet absorber include 2-ethyl-2′-ethoxy-oxalanilide (manufactured by Clariant Japan, trade name: Sundebore VSU).

  Among the above-described ultraviolet absorbers, benzotriazoles and the like are preferably used from the viewpoint that resin degradation due to ultraviolet irradiation can be suppressed.

Further, when it is desired to efficiently absorb a wavelength around 380 nm, a triazine ultraviolet absorber is preferably used.
As such an ultraviolet absorber,
2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine (manufactured by ADEKA; LA-F70),
And hydroxyphenyltriazine-based ultraviolet absorbers (manufactured by BASF; TINUVIN477-D and TINUVIN460) which are analogs thereof.

In addition, the maximum value ε _max of the molar extinction coefficient of the ultraviolet absorber is measured as follows.
Add 10.00 mg of UV absorber to 1 L of cyclohexane and dissolve it so that there is no undissolved material by visual observation. This solution is poured into a 1 cm × 1 cm × 3 cm quartz glass cell, and the absorbance at a wavelength of 380 to 450 nm is measured using a U-3410 spectrophotometer manufactured by Hitachi, Ltd. The maximum value ε _max of the molar extinction coefficient is calculated from the molecular weight (M _UV ) of the ultraviolet absorber and the maximum value (A _max ) of the measured absorbance according to the following formula.

ε _max = [A _max / (10 × 10 ⁻³ )] × M _UV

The antioxidant alone has an effect of preventing oxidative deterioration of the resin in the presence of oxygen.
Examples thereof include phosphorus antioxidants, hindered phenol antioxidants, and thioether antioxidants. These antioxidants can be used alone or in combination of two or more.
Among these, from the viewpoint of the effect of preventing deterioration of optical properties due to coloring, a phosphorus-based antioxidant and a hindered phenol-based antioxidant are preferable, and a combined use of a phosphorus-based antioxidant and a hindered phenol-based antioxidant is more preferable. .
When using together phosphorus antioxidant and hindered phenolic antioxidant, the usage-amount of phosphorus antioxidant: The usage-amount of hindered phenolic antioxidant is 1: 5-2 by mass ratio. 1 is preferable, and 1: 2 to 1: 1 is more preferable.

  As phosphorus antioxidants, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite (manufactured by ADEKA; trade name: ADK STAB HP-10), tris (2,4-di-) t-Butylphenyl) phosphite (manufactured by BASF; trade name: IRGAFOS168) and 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa 3,9-diphosphaspiro [5.5] undecane (manufactured by ADEKA; trade name: ADK STAB PEP-36) and the like are preferable.

  As the hindered phenol-based antioxidant, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (manufactured by BASF; trade name: IRGANO01010), and octadecyl-3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (manufactured by BASF; trade name IRGANO01076) is preferred.

The thermal degradation inhibitor can prevent thermal degradation of the resin by scavenging polymer radicals generated when exposed to high heat in a substantially oxygen-free state.
As the thermal degradation inhibitor, 2-t-butyl-6- (3′-t-butyl-5′-methyl-hydroxybenzyl) -4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd .; trade name Sumilyzer GM), and 2,4-di-t-amyl-6- (3 ′, 5′-di-t-amyl-2′-hydroxy-α-methylbenzyl) phenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd .; trade name Sumitizer GS) preferable.

As the polymer processing aid, polymer particles having a particle diameter of 0.05 to 0.5 μm, usually produced by an emulsion polymerization method, are used. Such polymer particles may be single layer particles composed of a single composition and single intrinsic viscosity polymer, or may be multilayer particles composed of two or more polymers having different compositions or intrinsic viscosities. Good.
In particular, particles having a two-layer structure having a polymer layer having a relatively low intrinsic viscosity in the inner layer and a polymer layer having a relatively high intrinsic viscosity of 5 dl / g or more in the outer layer are preferable.

  The average degree of polymerization of the polymer processing aid is preferably 3,000 to 40,000, more preferably 6,000 to 30,000, and particularly preferably 10,000 to 25,000.

  As the composition of the polymer processing aid, a polymer compound comprising 60% by mass or more of methyl methacrylate units and 40% by mass or less of vinyl monomer units copolymerizable therewith is preferable.

As a vinyl monomer copolymerizable with methyl methacrylate,
Methacrylic acid esters such as ethyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate;
Acrylic esters such as ethyl acrylate, methyl acrylate, butyl acrylate, and cyclohexyl acrylate,
Aromatic vinyl compounds such as styrene, p-methylstyrene, and o-methylstyrene;
Maleimide compounds such as N-propylmaleimide, N-cyclohexylmaleimide, and N-o-chlorophenylmaleimide;
Multifunctional, such as ethylene glycol dimethacrylate, propylene glycol dimethacrylate, triethylene glycol dimethacrylate, hexanediol dimethacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, triethylene glycol diacrylate, allyl methacrylate, and triallyl isocyanurate And monomers.

  Specifically, the polymer processing aid is preferably the METABRENE-P series manufactured by Mitsubishi Rayon Co., or the paraloid series manufactured by Rohm and Haas.

  The polymer processing aid preferably has an intrinsic viscosity of 3 to 6 dl / g. If the intrinsic viscosity is too small, the effect of improving the moldability of the nailing resin sheet of the present invention tends to be low. If the intrinsic viscosity is excessive, the moldability of the nailing resin sheet of the present invention tends to be lowered.

  In the present specification, unless otherwise specified, the average degree of polymerization of the polymer processing aid is a PMMA equivalent degree of polymerization measured at 20 ° C. using chloroform as a solvent using an automatically diluted capillary viscometer (Ubbelohde type). .

  The total amount of additives that can be contained in the nailing resin sheet of the present invention is preferably 7% by mass or less, more preferably 5% by mass or less, and particularly preferably 4% by mass or less.

(Manufacturing method of resin sheet for nailing)
The nailing resin sheet of the present invention is produced by a known molding method such as an extrusion molding method, a cast molding method, and an injection molding method.
As described above, since the internal residual stress and the residual stress difference between the front and back surfaces can be effectively reduced, the extrusion molding method is preferable.

According to the present invention, a method for producing a nailing resin sheet is obtained by melting and kneading a plurality of kinds of raw materials including a methacrylic resin (A) and an acrylic rubber (B) as main components to obtain a resin composition (C). Preparing step (1);
It is preferable to have a step (2) of extruding the resin composition (C).

<Step (1)>
For example, the resin composition (C) can be produced by melt-kneading the methacrylic resin (A), the acrylic rubber (B), and the optional components as necessary, which are the main components.
In the step (1), a plurality of types of raw materials may be melt-kneaded all at once, or a plurality of types of raw materials may be divided into a plurality of times and melt-kneaded.
The melt-kneading can be performed using, for example, a melt-kneader such as a kneader ruder, an extruder, a mixing roll, and a Banbury mixer.
The kneading temperature is appropriately adjusted according to the melting temperature of the resin component, and is usually preferably in the range of 150 ° C to 300 ° C.

  The melt flow rate (MFR) determined by measuring the resin composition (C) at 230 ° C. and a load of 3.8 kg is preferably 0.1 g / 10 min or more, more preferably 0.2 to 30 g / 10 minutes, more preferably 0.5 to 20 g / 10 minutes, particularly preferably 1.0 to 10 g / 10 minutes.

  The glass transition temperature (Tg) of the resin composition (C) is preferably 100 ° C. or higher. The upper limit of the glass transition temperature (Tg) of the resin composition (C) is not particularly limited, and is preferably 130 ° C.

  The resin composition (C) can be in the form of pellets or the like as necessary in order to enhance convenience during storage, transportation, or molding.

<Step (2)>
With reference to drawings, the structure of the manufacturing apparatus of the resin sheet of one Embodiment which concerns on this invention, and the manufacturing method using the same are demonstrated.
FIG. 1 is a schematic diagram of a manufacturing apparatus.

As shown in FIG. 1, the resin sheet manufacturing apparatus 1 includes an extrusion molding unit 110 that heats and melts a raw material resin composition 210M (resin composition (C)) and extrudes it into a sheet shape.
In this embodiment,
The extrusion means 110 is
A raw material charging unit 111 such as a hopper into which the raw material resin composition 210M is charged;
A screw part 112 that heats and melts and extrudes the resin composition 210M;
It is an extruder with a T die provided with a T die 113 including a discharge port 113A for discharging the heat-melted resin composition 210M into a sheet shape.

  The temperature of the resin sheet 210 discharged from the T die 113 is preferably 160 to 270 ° C, more preferably 220 to 260 ° C.

The nail driving resin sheet manufacturing apparatus 1 also adds a sheet-like material that is arranged adjacent to each other with a separation distance of a separation distance corresponding to a desired thickness of the resin sheet 210 and is extruded by the extrusion molding means 110. It has the cooling roll unit 120 which consists of several cooling rolls cooled while pressing.
The cooling roll unit 120 includes at least a first cooling roll 121 and a second cooling roll 122 having a separation portion below the discharge port 113 </ b> A of the T die 113.

  The sheet-like material pushed out from the T die 113 is sandwiched between the first cooling roll 121 and the second cooling roll 122, and is pressurized and cooled to become the resin sheet 210. At this time, the resin sheet 210 is not sufficiently cooled and is not completely solidified.

In the illustrated example, the cooling roll unit 120 includes a first cooling roll 121, a second cooling roll 122, a third cooling roll 123, and a fourth cooling roll 124.
The obtained resin sheet 210 sandwiched between the first cooling roll 121 and the second cooling roll 122 and pressurized and cooled is separated from the first cooling roll 121 by the second cooling roll 122. It is cooled while passing on the surface, and is supplied between the second cooling roll 122 and the third cooling roll 123 and pressurized.
The resin sheet 210 is further cooled while passing on the surface of the third cooling roll 123 away from the second cooling roll 122, and is provided between the third cooling roll 123 and the fourth cooling roll 124, Pressurized.
The resin sheet 210 is further cooled while passing through the surface of the fourth cooling roll 124 away from the third cooling roll 123 and then moves away from the fourth cooling roll 124 and proceeds to the next step. At this point, the resin sheet 210 has not been sufficiently cooled and has not completely solidified.

In the present embodiment, the T die 113 and the cooling roll unit 120 of the extrusion molding unit 110 are disposed in the first manufacturing chamber R1.
The environmental temperature T1 in the first manufacturing chamber R1 is not particularly adjusted, and is, for example, about 35 to 40 ° C. higher than normal temperature (20 to 25 ° C.) due to the presence of the heated molten resin.

In the present embodiment, a second manufacturing chamber R2 is provided adjacent to the first manufacturing chamber R1.
The environmental temperature T2 in the second manufacturing chamber R2 is adjusted within the temperature range described below in order to gradually cool the resin sheet 210 obtained by being pressurized and cooled by the cooling roll unit 120.
The environmental temperature T2 in the second manufacturing room R2 can be adjusted using a known air conditioner or the like.

The nail driving resin sheet manufacturing apparatus 1 also includes a protective film bonding means 130 for bonding the protective film 220 to the front and back surfaces of the manufactured resin sheet 210.
The protective film sticking means 130 includes a first protective film roll 131 that supplies the protective film 220 to the surface of the resin sheet 210, and a second protective film roll 132 that supplies the protective film 220 to the back surface of the resin sheet 210. Including.
The protective film sticking means 130 is provided outside the second manufacturing chamber R2.
Since the resin sheet 210 after being gradually cooled in the second manufacturing room R2 is sufficiently cooled and sufficiently solidified, the attaching process of the protective film 220 needs to adjust the environmental temperature in particular. Absent.

  The nail driving resin sheet manufacturing apparatus 1 also includes a pulling means 140 that expresses a force to pull the manufactured resin sheet 210. The take-up means 140 includes a pair of take-up rolls 141 and 142 that are arranged vertically so as to face each other with a separation portion having a separation distance corresponding to a desired thickness of the resin sheet 210.

The nailing resin sheet manufacturing apparatus 1 also includes a known cutting means (not shown) for cutting the resin sheet 210 having the protective film 220 attached on both sides into a plate shape.
In addition, the structure of the manufacturing apparatus 1 of the nailing resin sheet of this embodiment is only an example, and can change a design suitably.

The resin sheet 210 is manufactured as follows by using the manufacturing apparatus 1 for a nail driving resin sheet of the present embodiment.
First, the resin composition 210M as a raw material is heated and melted by the extrusion molding means 110 and extruded into a sheet shape.
Next, the sheet-like material extruded by the extrusion molding unit 110 is pressurized and cooled by the cooling roll unit 120, and the resin sheet 210 is obtained.
Next, the obtained resin sheet 210 is gradually cooled in the second manufacturing chamber R2.
Next, the protective film 220 is attached to both surfaces of the resin sheet 210 by the protective film attaching means 130.

In the above-mentioned extrusion molding method, the present inventors define the following three manufacturing conditions (manufacturing conditions 1 to 3) within a suitable range among a number of manufacturing conditions, whereby the surface layer portion and the back layer portion. The maximum absolute value εa of the internal residual stress excluding is adjusted to 100 kg / cm ² or less, preferably 60 kg / cm ² or less, more preferably 50 kg / cm ² or less, and when viewed in the thickness direction, The maximum absolute value εb of the difference between the residual stress and the residual stress in the back layer can be adjusted to preferably 80 kg / cm ² or less, more preferably 70 kg / cm ² or less, and particularly preferably 50 kg / cm ² or less. Is heading.

When carrying out the post-process (3), the maximum absolute value εa of the internal residual stress excluding the surface layer part and the back layer part is 100 kg / cm ² or less, regardless of whether the following production conditions 1 to 3 are satisfied. The maximum absolute value εb of the difference between the residual stress in the surface layer portion and the residual stress in the back layer portion is preferably adjusted to 60 kg / cm ² or less, more preferably 50 kg / cm ² or less, and as viewed in the thickness direction. , Preferably 80 kg / cm ² or less, more preferably 70 kg / cm ² or less, particularly preferably 50 kg / cm ² or less.

In the present embodiment, as the manufacturing condition 1, the temperature TS of the entire resin sheet 210 is set to 115 at the time when the cooling roll unit 120 moves away from the cooling roll (the fourth cooling roll 124 in the example shown in FIG. 1). It adjusts in the range of -165 degreeC, Preferably it is 120-160 degreeC.
By satisfying the manufacturing condition 1, the maximum absolute value εb of the difference between the residual stress in the surface layer portion and the residual stress in the back layer portion is preferably 80 kg / cm ² or less, more preferably in the thickness direction. It can be adjusted to 70 kg / cm ² or less, particularly preferably 50 kg / cm ² or less.

When the temperature TS of the resin sheet 210 at the time of moving away from the most downstream cooling roll (the fourth cooling roll 124 in the example shown in FIG. 1) of the cooling roll unit 120 is less than 115 ° C., the absolute value of the difference in residual stress between the front and back surfaces Tend to be larger. This is presumably because the surface of the resin sheet 210 in the cooling roll unit 120 tends to be rapidly cooled.
When the temperature of the resin sheet 210 at the time of moving away from the cooling roll at the most downstream side of the cooling roll unit 120 (the fourth cooling roll 124 in the example shown in FIG. 1) exceeds 165 ° C., the surface smoothness of the obtained nailing resin sheet is obtained. Tend to decrease.

In this embodiment, at the time of leaving from the most downstream cooling roll of the cooling roll unit 120, the cooling roll is set so that the entire temperature TS of the resin sheet 210 is within a range of 115 to 165 ° C, preferably 120 to 160 ° C. The number of cooling rolls used in the unit 120 and the temperature of each cooling roll are set.
The number of cooling rolls is preferably 3-4.
As for the temperature of each cooling roll, 70-110 degreeC is preferable.

  The temperature of the resin sheet 210 on the production line can be measured by a known method. For example, the surface temperature of the resin sheet 210 can be measured using a non-contact thermometer such as an infrared radiation thermometer. .

In the cooling roll unit 120,
The circumferential speed of the first cooling roll 121 is V1, the circumferential speed of the second cooling roll 122 is V2, the circumferential speed of the third cooling roll 123 is V3, and the circumferential speed of the fourth cooling roll 124 is V4. And
The peripheral speed of the pair of take-up rolls 141 and 142 is VX.
In order to smoothly take out the resin sheet 210, VX is usually set equal to or higher than V1 to V4.
The temperature of the resin sheet 210 passing between the pair of take-up rolls 141 and 142 is lower than the temperature of the resin sheet 210 passing through the cooling roll unit 120. In consideration of the thermal contraction amount of the temperature difference resin sheet 210, VX may be set slightly lower than V1 to V4.

In this embodiment, as the manufacturing condition 2, the ratio of the peripheral speed VX of the pair of take-up rolls 141 and 142 to the peripheral speed V2 of the second cooling roll 122 (peripheral speed ratio VR = VX / V2) is 0.98 to 1. 01, preferably within the range of 0.99 to 1.01.
Moreover, in this embodiment, as manufacturing conditions 3, environmental temperature T2 of 2nd manufacturing chamber R2 between the cooling roll unit 120 and a pair of take-up rolls 141 and 142 is 5-50 degreeC, Preferably it is 20-50 degreeC. Adjust the temperature within the range.
By satisfying the production conditions 2 and 3, the maximum absolute value εa of the internal residual stress excluding the surface layer portion and the back layer portion is 100 kg / cm ² or less, preferably 60 kg / cm ² or less, more preferably 50 kg / cm. It can be adjusted to ² or less.

When the peripheral speed ratio VR (VX / V2) exceeds 1.01 and the environmental temperature T2 of the second manufacturing chamber R2 is less than 5 ° C., the internal residual tensile stress in the flow direction tends to increase.
This is presumed to be due to the following reason.
When the peripheral speed ratio VR exceeds 1.01, the tensile stress applied to the resin sheet 210 tends to increase. In addition, when the environmental temperature T2 in the second manufacturing chamber R2 is less than 5 ° C., the temperature of the resin sheet 210 passing through the second manufacturing chamber R2 is lowered similarly to the environmental temperature T2. There is a tendency for thermal shrinkage to increase and tensile stress in the flow direction to increase.

When the peripheral speed ratio VR (VX / V2) is less than 0.98, the surface smoothness of the resin sheet 210 tends to be lowered. When the peripheral speed ratio VR is less than 0.98, the resin sheet 210 is cooled most downstream. In some cases, surface shape unevenness may occur due to a change in the position when peeling from the roll (the fourth cooling roll 124 in the example shown in FIG. 1). This surface shape unevenness is generally called “chatter mark”.
When the environmental temperature T2 of the second manufacturing room R2 exceeds 50 ° C., the nail driving resin sheet is not efficiently cooled, and the manufacturing efficiency tends to be poor.

<Step (3)>
Method of manufacturing a nailing resin sheet of the present invention, the step (2) further after the (extrusion step), the obtained resin sheet at a temperature higher than the room temperature (20-25 ° C.), and the configuration A step (3) of heating at a temperature lower than the glass transition temperature (Tg) of the resin composition can be included.

  Step (3) can be carried out, for example, by cutting resin sheet 210 obtained after step (2) (extrusion molding step) with protective film 220 attached on both sides into a length of about 5 m. .

The present inventors can reduce the internal residual stress and the difference between the residual stresses on the front and back sides by performing the step (3) after the step (2) regardless of the satisfaction of the manufacturing conditions 1 to 3 in the step (2). Is heading.
Specifically, the present inventors carry out the step (3) after the step (2) regardless of the satisfaction of the production conditions 1 to 3 in the step (2), so that the surface layer portion and the back layer portion are The maximum absolute value εa of the internal residual stress is adjusted to 100 kg / cm ² or less, preferably 60 kg / cm ² or less, more preferably 50 kg / cm ² or less. The maximum absolute value εb of the difference between the stress and the residual stress in the back layer can be adjusted to preferably 80 kg / cm ² or less, more preferably 70 kg / cm ² or less, and particularly preferably 50 kg / cm ² or less. Heading.

Since the internal residual stress and the residual stress difference between the front and back surfaces can be effectively reduced, it is particularly preferable to carry out the step (3) after satisfying the manufacturing conditions 1 to 3 in the step (2).
The heating method is not particularly limited, and examples include an infrared method, a warm air method, and an electric heater method. A plurality of heating methods may be combined.
The heating temperature in this step is preferably 60 to 100 ° C.
The heating time in this step is not particularly limited and is determined according to the heating temperature, and is preferably 5 minutes to 60 minutes.
In order to maintain the reduced residual stress, the resin sheet after the heat treatment is preferably cooled (including natural cooling) in an environment where no stress is generated. For example, the resin sheet after the heat treatment is preferably naturally cooled in a stationary state in an environment of 25 to 30 ° C.

(Process (4))
After performing the step (1), the step (2), and the step (3) as necessary, the resin sheet 210 having the protective film 220 bonded on both sides is formed into a plate shape by a known cutting means (not shown). Disconnect.
As described above, the plate-like resin sheet 210 is manufactured.

  As described above, according to the present invention, the nail breaks and bends at the time of nailing or after nailing, the nail loosening and nailing after nailing, the warpage of the sheet, and the nail omission and the position of the nail by this. It is possible to provide a nailing resin sheet capable of suppressing changes and a method for manufacturing the same.

  Examples and comparative examples according to the present invention will be described.

Example 1
<Production of Acrylic Three-Layer Structure Particle (BX-1a)>
In a reactor equipped with a reflux condenser, 145 parts by mass of ion-exchanged water, 0.45 parts by mass of sodium stearate (SS), 0.08 parts by mass of sodium lauryl sarcosinate (LSS), and 0.05% of sodium carbonate (SC) After adding parts by mass and stirring and dissolving, 32.9 parts by mass of methyl methacrylate (MMA), 2.1 parts by mass of methyl acrylate (MA), and allyl methacrylate (ALMA) 0.07 as a crosslinking agent. A mass part was added and the temperature was raised to 80 ° C. while stirring. Next, 1.8 parts by mass of a 2% potassium persulfate aqueous solution was added, and the temperature was raised to 80 ° C. and held for 60 minutes to obtain a latex.
In the presence of the latex, 2.2 parts by mass of a 2% aqueous potassium persulfate solution was added, and 36.99 parts by mass of butyl acrylate (BA), 8.01 parts by mass of styrene (ST), and methacryl as a crosslinking agent. A monomer mixture consisting of 0.9 parts by mass of allyl acid (ALMA) was continuously added over 60 minutes, and held for 30 minutes after completion of the addition.
Next, 1.0 part by mass of a 2% aqueous potassium persulfate solution was added in the presence of the latex, 18.8 parts by mass of methyl methacrylate (MMA), 1.2 parts by mass of methyl acrylate (MA), and n-octyl mercaptan. (N-OM) A monomer mixture consisting of 0.04 parts by mass was continuously added over 30 minutes, and held for 60 minutes after completion of the addition.
As described above, an acrylic having an average particle diameter of 0.23 μm, which is composed of a hard layer (first layer), a soft layer (second layer, rubber layer), and a hard layer (third layer) from the center side. A latex containing 40% by mass of system three-layer structured particles (BX-1a) was obtained.
The monomer composition of each layer and the mass ratio of each layer of the resulting acrylic three-layer structured particle (BX-1a) are as shown in Table 1.

<Manufacture of raw material resin composition>
For dispersing the acrylic three-layer structure particles (BX-1a) obtained in Production Example 1, 90 mass parts of MMA and 10 mass parts of MA are obtained by emulsion polymerization, and the average particle diameter is 0.13 μm. A latex of the first methacrylic resin (A-1) having a polymerization degree of 960 was prepared.
A latex obtained by mixing the acrylic three-layer structured particle (BX-1a) latex obtained in Production Example 1 and the first methacrylic resin (A-1) latex at a mass ratio of 67:33 is coagulated by a known method. Filtration, washing, dehydration and drying yielded a first methacrylic resin composition (C-1). The MVR (melt volume flow rate) of the first methacrylic resin composition (C-1) (impact methacrylic resin composition) was 1.5 g / 10 min.

  Separately, a powdery second methacrylic resin obtained by suspension polymerization of 94 parts by mass of MMA and 6 parts by mass of MA, having an average particle diameter of 0.13 μm and a polymerization degree of 1550 ( A-2) ("Parapet (registered trademark) EH" manufactured by Kuraray Co., Ltd.) was prepared.The MVR of the second methacrylic resin (A-2) was 1.3 g / 10 min.

Using a mixer mixer manufactured by Kubota Corporation, the first methacrylic resin composition (C-1) and the second methacrylic resin (A-2) were mixed at a mass ratio of 43:57. The mixture was melt-mixed to obtain a second methacrylic resin composition (C-2). This second methacrylic resin composition (C-2) was used as a raw material resin composition for the resin sheet.
Content C of the acrylic three-layer structure particles (BX-1a) in the second methacrylic resin composition (C-2) was 23% by mass.

<Manufacture of resin sheet>
Using the above-obtained second methacrylic resin composition (C-2), a methacrylic resin sheet having a sheet thickness t of 10 mm was extrusion molded using a manufacturing apparatus as shown in FIG.
As the extrusion molding means 110, a 150 mmφ single screw extruder manufactured by Toshiba Machine Co., Ltd. was used.
By adjusting the temperature of the second cooling roll 122 and the fourth cooling roll 124, the overall temperature of the methacrylic resin sheet at the time of leaving from the most downstream cooling roll (in this example, the fourth cooling roll 124) TS was adjusted to 140 ° C.
The environmental temperature (environment temperature between the cooling roll unit and the pair of take-up rolls) T2 of the second manufacturing chamber R2 was 25 ° C.
The ratio of the peripheral speed VX of the pair of take-up rolls 141 and 142 to the peripheral speed V2 of the second cooling roll 122 (peripheral speed ratio VR = VX / V2) was 1.00.

  When the cross section of the obtained resin sheet was observed using TEM, the average particle diameter of the acrylic three-layer structure particles (BX-1a) in the sheet was 0.21 μm.

Table 2 shows the main production conditions.
Each abbreviation in Table 2 is as follows.
C: Content of acrylic three-layer structure particles (BX-1a) in the raw material resin composition,
t (mm): thickness of the produced resin sheet,
TS: the overall temperature of the resin sheet at the time of leaving the most downstream cooling roll,
VR: ratio of the peripheral speed VX of the pair of take-up rolls 141 and 142 to the peripheral speed V2 of the second cooling roll 122 (peripheral speed ratio, VX / V2),
T2: Environmental temperature of the second manufacturing chamber R2 (environment temperature between the cooling roll unit and the pair of take-up rolls).

(Examples 2 to 12)
In each example of Examples 2-12, it is the same as Example 1 except having changed parameter C, t, TS, VR, T2 of the manufacturing conditions of an extrusion molding process (process (2)) into what is shown in Table 2. Thus, a methacrylic resin sheet was obtained.

(Examples 21 to 26)
In each example of Examples 21 to 26, a methacrylic resin sheet was extruded under the conditions shown in Table 3 in the same manner as Example 1 (step (2)). Furthermore, in each of these examples, the resin sheet after extrusion molding was cut out to a length of 5 m in the extrusion direction, the sheet cut out by the hot air method was heated under the conditions shown in Table 3, and then placed in an environment of 25 to 30 ° C. It left still and cooled naturally (process (3)). Then, it cut | disconnected in plate shape.

(Comparative Examples 1-4)
In each example of Comparative Examples 1 to 4, the same as Example 1 except that the parameters C, t, TS, VR, and T2 of the manufacturing conditions in the extrusion process (step (2)) were changed to those shown in Table 4. Thus, a methacrylic resin sheet was obtained.

(productivity)
In each of Examples 1 to 12, Examples 21 to 26, and Comparative Examples 1 to 4, the productivity of the obtained resin sheets was evaluated according to the following criteria.
<Criteria>
A (excellent): Chatter marks are not seen on the surface of the resin sheet.
○ (good): A slight chatter mark was observed on the surface of the resin sheet.
Δ (possible): Some chatter marks were seen on the surface of the resin sheet, but there is no practical problem for a ball game machine.
X (impossible): Many chatter marks are seen on the surface of the resin sheet, which impedes practical use for a ball game machine.

(Evaluation of residual stress)
In each of Examples 1 to 12, Examples 21 to 26, and Comparative Examples 1 to 4, the obtained resin sheets were subjected to the method defined in the section “Means for Solving the Problems” The maximum absolute value εa of the internal residual stress excluding the surface layer portion and the back layer portion, and the maximum absolute value εb of the difference between the residual stress in the surface layer portion and the residual stress in the back layer portion were determined.

(Nail driveability)
In each example of Examples 1-12, Examples 21-26, and Comparative Examples 1-4, a drilling machine with a diameter of 1.73 mmφ was used to form one through hole with respect to the obtained resin sheet. Formed.
Next, using “Autograph AG-2000B” manufactured by Shimadzu Corporation, brass threaded nails (with a diameter of 1.85 mmφ, excluding the nail head) inside the through hole at a speed of 500 mm / min. 26.5 mm in length and 5.5 mm in length of the threaded portion) was driven by the depth of the sheet thickness.
The nail driveability was visually evaluated according to the following criteria.
<Criteria>
○ (good): Nail breakage and nail bending did not occur.
Δ (possible): Nail breakage did not occur, but nail bending occurred.
X (impossible): Nail breakage occurred.

(Punching ability)
In each example of Examples 1-12, Examples 21-26, and Comparative Examples 1-4, a drilling machine with a 1.73 mmφ diameter was used for the obtained resin sheets, and a total of 10 pieces at 10 mm intervals Through-holes were formed.
Next, using “Autograph AG-2000B” manufactured by Shimadzu Corporation, brass threaded nails (with a diameter of 1.85 mmφ, excluding the nail head) are inserted into each through-hole at a speed of 500 mm / min. 26.5 mm in length and 5.5 mm in length of the threaded portion) was driven by the depth of the sheet thickness.
Next, using a hot air oven, the resin sheet was heated at 45 ° C. for 1 hour in a suspended state, and then the resin sheet was taken out of the hot air oven and sufficiently naturally cooled at room temperature.
Next, using an autograph “AG-2000B” manufactured by Shimadzu Corporation, an arbitrary nail is selected from a total of 10 nails driven into the resin sheet, and the nail head is held with a chuck. The maximum load (kg) when pulled out at a speed of 25 mm per minute was measured.
The above measurements were carried out for each of ten nails, and the average value of the maximum loads was determined as the nail pulling strength.
<Criteria>
○ (good): The nail pull strength is greater than 50 kgf.
Δ (possible): Nailing strength is 20 kgf or more and less than 50 kgf.
X (impossible): The measurement cannot be performed because the nail pulling strength is less than 20 kgf or the nail is broken when the nail is driven.

(Nail position change)
In each of Examples 1 to 12, Examples 21 to 26, and Comparative Examples 1 to 4, the drilling of the 1.73 mmφ diameter was performed on the obtained resin sheet using a drilling machine, and two through holes were formed. Formed. The distance between the central axes of the two through-holes was set to 13 mm. Next, using “Autograph AG-2000B” manufactured by Shimadzu Corporation, a brass twisted screw was introduced into each through-hole at a speed of 500 mm / min. A nail tip (1.85 mmφ diameter, length of the portion excluding the nail head 26.5 mm, length of the screw portion 5.5 mm) was driven by the depth of the sheet thickness. The center axis interval (nail interval) between the two nails was 13 mm.
Next, a liquid crystal display panel with a backlight was installed 30 mm behind the surface (back surface) opposite to the nail driving surface of the resin sheet. In addition, air was circulated between the resin sheet and the liquid crystal display panel with a backlight so as not to collect heat.
When the liquid crystal display panel with a backlight was operated in a state where the surface temperature of the resin sheet was 22 ° C. in an environment of room temperature 22 ° C., the back surface temperature of the resin sheet reached 40 ° C. after 4 to 5 hours. The back surface temperature remained at 40 ° C. after 10 hours from the start of operation.
The operation was stopped when 10 hours passed from the start of operation, and the distance between the central axes of the two nails (nail interval) was measured again.
In this evaluation, a digital microscope (VHX-900 manufactured by Keyence) was used for measuring the distance between the central axes of the nails.
Prior to the start of operation of a liquid crystal display panel with a backlight, the change in nail position after 10 hours from the start of operation was evaluated according to the following criteria.
<Criteria>
○ (good): The change in nail spacing was less than 0.05 mm.
Δ (possible): The change in nail interval was 0.05 mm or more and 0.12 mm or less.
X (impossible): The change in nail interval was more than 0.12 mm.

(Haze value)
In each example of Examples 1 to 12, Examples 21 to 26, and Comparative Examples 1 to 4, the obtained resin sheets were subjected to a haze meter (Murakami Color Research Laboratory, HM-150) according to JIS K7136. The haze value was measured at 23 ° C.

(Evaluation results)
The evaluation results are shown in Tables 2 to 4.
In Examples 1 to 12 and Examples 21 to 26, the content C of the acrylic three-layer structure particles (BX-1a) in the raw resin composition was set in the range of 15 to 50% by mass.
In Examples 1 to 12 and Examples 21 to 26, the sheet thickness t was set in the range of 5 to 10 mm.

In Examples 1 to 12, the overall temperature TS of the methacrylic resin sheet at the time of leaving the most downstream cooling roll among the plurality of cooling rolls of the cooling roll unit was adjusted within the range of 115 to 165 ° C.
In Examples 1 to 12, the ratio of the peripheral speed VX of the pair of take-up rolls to the peripheral speed V2 of the second cooling roll (peripheral speed ratio VR = VX / V2) is adjusted within the range of 0.98 to 1.01. did.
In Examples 1-12, between the cooling roll unit and the pair of take-up rolls, the methacrylic resin sheet was passed through the environment adjusted to a temperature of 5 to 25 ° C.
In Examples 1 to 12, the heating step (step (3)) was not performed after the extrusion step (step (2)).
In Examples 1 to 12, when viewed in the thickness direction, the maximum absolute value εa of the internal residual stress excluding the surface layer portion and the back layer portion is 100 kg / cm ² or less. A resin sheet having a maximum absolute value εb of a difference between the residual stress and the residual stress of the back layer portion of 80 kg / cm ² or less could be stably produced.

Each of the resin sheets obtained in Examples 1 to 12 had relatively good productivity, nail breaking and bending during nailing or nailing, nail loosening and nailing after nailing, and sheet Warping and nail omission or nail position change due to this are suppressed, making it suitable for use in ball game machines and the like.
From a comparison between Example 1 and Example 4, it was found that the sheet thickness t is preferably 5 mm or more, and more preferably 10 mm or more.
From a comparison between Example 1 and Example 7, the environmental temperature (the environmental temperature between the cooling roll unit and the pair of take-up rolls) T2 of the second manufacturing chamber R2 is preferably 5 to 50 ° C., and 20 to 50. It has been found that ° C is more preferred.
From a comparison between Example 1, Example 8 and Example 12, the content C of the acrylic rubber (B) in the raw resin composition is preferably 15% by mass or more, more preferably 15 to 45% by mass. More preferably, it is 15 to 30% by mass, more preferably 20 to 30% by mass, and particularly preferably 25 to 30% by mass.
In Example 12, in which the content C of the acrylic rubber (B) in the raw resin composition was 50% by mass more than in the other examples, the haze value was higher than in the other examples. It was.

In Examples 21 to 26, the heating step (step (3)) was performed after the extrusion step (step (2)).
In Examples 21 to 26, the effect of reducing the residual stress and the difference between the residual stresses on the front and back sides was observed with respect to Example 1 in which the process (2) was performed under the same conditions and the process (3) was not performed.
In Examples 21 to 26, the maximum absolute value εa of the internal residual stress excluding the surface layer portion and the back layer portion when viewed in the thickness direction is 100 kg / cm ² or less. A resin sheet having a maximum absolute value εb of a difference between the residual stress and the residual stress of the back layer portion of 80 kg / cm ² or less could be stably produced.
All of the resin sheets obtained in Examples 21 to 26 had relatively good productivity, nail breaking and bending at the time of nailing or after nailing, nail loosening and nailing after nailing, and sheets Warping and nail omission or nail position change due to this are suppressed, making it suitable for use in ball game machines and the like.

In Comparative Example 1 in which the ratio of the peripheral speed VX of the pair of take-up rolls to the peripheral speed V2 of the second cooling roll (peripheral speed ratio VR = VX / V2) is 1.02, the surface layer portion is seen in the thickness direction. The maximum absolute value εa of the internal residual stress excluding the back layer is more than 100 kg / cm ² , and nail breakage or bending during nailing or nailing, and nail loosening or nailing after nailing It was easy to occur and was unsuitable for a ball game machine.

  In Comparative Example 2 in which the sheet thickness t is less than 5 mm, the nail breaks or bends when nailing or after nailing, the nail loosening or nailing after nailing, warping the sheet, and the nail missing or nailing due to this. Changes in position are likely to occur, making it unsuitable for use in ball game machines.

In Comparative Example 3 in which the environmental temperature of the second manufacturing chamber R2 (environmental temperature between the cooling roll unit and the pair of take-up rolls) T2 was 0 ° C., the surface layer part and the back layer part were viewed in the thickness direction. The maximum absolute value εa of the internal residual stress excluding is more than 100 kg / cm ² , and it is easy to cause nail breakage or bend when nailing or after nailing, as well as loosening or nailing after nailing. It was unsuitable for gaming machines.

  In Comparative Example 4 in which the content C of the acrylic rubber (B) in the raw material resin composition was less than 15% by mass, nail breaking or nail bending at the time of nailing or after nailing, and nail loosening after nailing or Nails are easily removed, making them unsuitable for ball game machines.

  The present invention is not limited to the above-described embodiments and examples, and can be appropriately modified without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 110 Extrusion molding means 111 Raw material input part 112 Screw part 113 T die 113A Discharge port 120 Cooling roll unit 121 1st cooling roll 122 2nd cooling roll 123 3rd cooling roll 124 4th cooling roll 130 Protection Film sticking means 131, 132 Protective film roll 140 Take-up means 141, 142 Take-up roll 210 Resin sheet 210M Resin composition 220 Protective film R1 First manufacturing room R2 Second manufacturing room

Claims (4)

It consists of a resin composition containing a methacrylic resin (A) and an acrylic rubber (B) as the main components,
The acrylic rubber (B) content in the resin composition is 15% by mass or more,
The thickness is 5 mm or more,
A method for producing a resin sheet for nailing in which the maximum absolute value of the internal residual stress excluding the surface layer portion and the back layer portion is 100 kg / cm ² or less as viewed in the thickness direction,
Extruding means for heating and melting the resin composition and extruding it into a sheet,
A cooling roll unit composed of a plurality of cooling rolls arranged adjacent to each other and cooled while pressurizing the sheet-like material extruded by the extrusion molding means;
Using a manufacturing apparatus provided with a pair of take-up rolls that are arranged to face each other and express the force of taking up the manufactured resin sheet,
Adjusting the overall temperature of the resin sheet within a range of 115 to 165 ° C. at the time of leaving the cooling roll on the most downstream side of the plurality of cooling rolls of the cooling roll unit;
Among the plurality of cooling rolls of the cooling roll unit, when the peripheral speed of the second cooling roll located second from the upstream side is V2, and the peripheral speed of the pair of take-up rolls is VX,
Adjust the ratio of the peripheral speed VX of the pair of take-up rolls to the circumferential velocity V2 of the second cooling roll (VX / V2) in the range of 0.98 to 1.01,
Between the cooling roll unit and the pair of take-up rolls, an extrusion molding step of allowing the resin sheet to pass through an environment adjusted in a range of 5 to 50 ° C. and gradually cooling the molding,
A heating step of heating at 60 to 100 ° C. with respect to the resin sheet obtained after the extrusion molding step,
Manufacturing method of resin sheet for nailing. 2. The maximum absolute value of the difference between the residual stress of the surface layer portion and the residual stress of the back layer portion is 80 kg / cm ² or less when the nailing resin sheet is viewed in the thickness direction. Method for manufacturing a resin sheet for nailing. The method for producing a nailing resin sheet according to claim 1 or 2, wherein the acrylic rubber (B) includes multilayer structure particles (BX) including at least one rubber layer. The method for producing a resin sheet for nailing according to claim 1 or 2, wherein the acrylic rubber (B) contains a block copolymer (BY).

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