JP2015134868A - Method for manufacturing thick film sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a thick film sheet capable of preventing a reduction in yield and increasing productivity.SOLUTION: The method for manufacturing a thick film sheet includes: a forming step of forming a polymerizable composition into a sheet of a predetermined thickness using a pressure roll; and a polymerizing step of polymerizing the polymerizable composition after the forming step. The polymerizable composition is held at the top and bottom thereof by an upper base material and a lower base material, respectively, and held at opposite ends in a width direction by restraining members. A thickness of the restraining member is equal to or greater than (the predetermined thickness - 2 mm) and equal to or smaller than (the predetermined thickness + 3.5 mm). Angle retaining members are placed between opposite ends in a width direction of the lower base material and a surface on which the lower base material is placed, and an angle θ that is formed between the opposite ends in the width direction of the base material and the surface when the angle retaining members raise the opposite ends in the width direction of the lower base material from the surface is 25 to 70 degrees.

Description

  The present invention relates to a method for producing a thick film sheet.

  In recent years, electronic components such as plasma display panels (PDP), integrated circuit (IC) chips, and the like have increased in heat generation as their performance has increased. As a result, it is necessary to take countermeasures against functional failures due to temperature rise. In general, a method of dissipating heat by attaching a heat sink such as a metal heat sink, a heat radiating plate, or a heat radiating fin to a heat generator provided in an electronic component or the like is employed. In order to efficiently conduct heat conduction from the heat generating body to the heat radiating body, a sheet-like member (heat conductive sheet) having high heat conductivity is sandwiched between the heat generating body and the heat radiating body.

  The thermally conductive sheet is a kind of resin sheet formed by adding various fillers to a resin. Such a resin sheet can be manufactured by, for example, forming a composition constituting the resin sheet into a predetermined thickness and then curing the composition. As a technique applicable to a method for producing a resin sheet, for example, in Patent Document 1, a kneaded material in which a heat conductive filler is mixed with a silicone rubber raw material is sandwiched between resin films and rolled by a calender roll, and a heating furnace (inside the furnace) A method is disclosed in which a sheet-like material is obtained by passing through and solidifying at a temperature of 100 ° C. or higher. According to such a technique, a resin sheet can be manufactured by pressing the composition which comprises a resin sheet with a roll etc., and making it harden | cure, after shape | molding in the sheet form of predetermined thickness.

JP 2002-167511 A

However, in the conventional method for producing a resin sheet as described above, the composition is formed in the width direction after the composition constituting the resin sheet is formed into a sheet having a predetermined thickness and before the shape is fixed. It spreads and becomes thin, and the shape sometimes collapses particularly at the end in the width direction. The portion whose shape has collapsed in this way is not a product but is discarded. Therefore, the yield of a resin sheet will fall, so that the part cut off is increased.
The ratio of the portion where the shape at the end in the width direction is broken is more suitable for the case where a thick film sheet is produced and the sol of the polymerizable composition whose shape is easily broken is used as a raw material. It will be big. Therefore, the decrease in yield in the case of producing a thick film resin sheet using a sol of the polymerizable composition as a raw material has become more remarkable.
Hereinafter, a thick film resin sheet made of the polymerizable composition as a raw material is simply referred to as a “thick film sheet”.

  Then, this invention makes it a subject to provide the manufacturing method of the thick film sheet | seat which can suppress the fall of a yield and can improve productivity.

  As a result of intensive studies in view of the above problems, the present inventors have found that when the polymerizable composition is molded into a sheet having a predetermined thickness and when the polymerization reaction is performed after the molding, And holding the both ends of the width direction with a restraining member having a specific thickness, and the angle holding portion makes the angle between the width direction both ends of the lower substrate and the mounting surface a specific range. By doing so, it was found that the ratio of the portion where the polymerizable composition spreads in the width direction and becomes thin and the shape collapses (hereinafter referred to as the thickness NG ratio) can be lowered.

  That is, the present invention is a method for producing a thick film sheet, a molding step for molding the polymerizable composition into a sheet having a predetermined thickness by a rolling roll, and a polymerization step for polymerizing the polymerizable composition after the molding step. And the polymerizable composition is sandwiched between the upper and lower base materials by the upper and lower base materials, and both ends in the width direction are sandwiched by the restraining member, and the thickness of the restraining member is (predetermined thickness). −2 mm) and (predetermined thickness + 3.5 mm) or less, and an angle holding member is disposed between the width direction both ends of the lower base material and the mounting surface of the lower base material, and the angle The angle θ formed between the both ends in the width direction of the base material and the placement surface formed by rising both ends in the width direction of the lower base material from the placement surface by the holding member is 25 degrees or more and 70 degrees or less. This is a method for producing a thick film sheet.

  In the polymerization step in the method for producing a thick film sheet of the present invention, the angle holding member is preferably arranged until at least the viscosity of the polymerizable composition is 150,000 mPa · s or more.

  Moreover, in the manufacturing method of the thick film sheet | seat of this invention, polymeric composition is (meth) acrylic acid ester polymer (A1), (meth) acrylic acid ester monomer ((alpha) 1), and polymerization initiator (B1). ) Is preferably included.

  In this specification, “(meth) acryl” means “acryl and / or methacryl”.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the thick film sheet which can suppress the fall of a yield and can improve productivity can be provided.

It is the figure which showed roughly a mode that the polymeric composition 1 was conveyed after shaping | molding process S1. FIG. 2A is a vertical sectional view taken along line IIa-IIa in FIG. FIG. 2B is a cross-sectional view from the same viewpoint as FIG. 2A after the polymerization step S2. FIG. 2C is a cross-sectional view from the same viewpoint as that in FIG. It is the schematic which looked at the mode of rolling in forming process S1 from the side.

  The above-mentioned operation and gain of the present invention will be clarified from embodiments for carrying out the invention described below. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to the embodiment. In addition, the figure shown below shows the structure schematically and does not show the magnitude | size and shape of each component accurately.

The method for producing a thick film sheet of the present invention includes a molding step S1 for molding the polymerizable composition into a sheet having a predetermined thickness, and a polymerization step S2 for polymerizing the polymerizable composition after the molding step S1. ing. In addition, the polymerizable composition is sandwiched between the upper and lower substrates and the both ends in the width direction by the restraining member, and the thickness of the restraining member is (predetermined thickness -2 mm) or more. And (predetermined thickness + 3.5 mm) or less, and an angle holding member is disposed between the width direction both ends of the lower base material and the mounting surface of the lower base material. The angle θ formed between the both ends in the width direction of the base material and the placement surface formed by rising both ends in the width direction of the side base material from the placement surface is 25 degrees or more and 70 degrees or less. .
Hereinafter, the manufacturing method of the thick film sheet | seat of this invention is demonstrated in detail, referring FIGS. 1-3.

FIG. 1 is a diagram illustrating a state in which a polymerizable composition 1 is conveyed after the forming step S1 in the method for producing a thick film sheet of the present invention. In FIG. 1, free rolls 6, 6, 6, 6... That are transport means are juxtaposed in the transport direction (the direction indicated by arrow X in FIG. 1), and on the free rolls 6, 6, 6, 6. The polymerizable composition 1, the upper substrate 2, the lower substrate 3, the restraining members 4 and 4, and the angle holding members 5 and 5 are disposed, and these members are conveyed in the direction indicated by the arrow X. The polymerizable composition 1, the upper substrate 2, the lower substrate 3, the restraining members 4 and 4, and the angle holding members 5 and 5 have a cross-sectional shape shown in FIG. Although extending in the transport direction, a part of the extending members is omitted here for easy understanding.
2A is a vertical sectional view taken along the line IIa-IIa in FIG. 1, and FIG. 2B is the same as FIG. 2A after the molding step S1 and further after the polymerization step S2. It is sectional drawing in a viewpoint. FIG. 2C is a cross-sectional view from the same viewpoint as that in FIG. 2A to 2C, the mounting surface 7 means a plane including all the tangent lines between the upper ends of the free rolls 6, 6, 6, 6. To do.
FIG. 3 is a schematic view of the rolling in the forming step S1 as viewed from the side.

  As can be seen from FIG. 1 and FIG. 2 (a), in the method for producing a thick film sheet of the present invention, the polymerizable composition 1 has upper and lower upper and lower bases 2 and 3 at both ends in the width direction. Are respectively held by the restraining members 4 and 4. Further, the angle holding members 5, 5 are arranged between the width direction both ends 3 a, 3 a of the lower base material 3 and the placement surface 7 of the lower base material 3, so that the lower base material 3 The width direction both ends 3a, 3a rise from the placement surface 7 and, as shown in FIG. 2A, the angle between the width direction both ends 3a, 3a of the lower substrate 3 and the placement surface 7 θ is formed.

  The upper substrate 2 and the lower substrate 3 are members that smoothly form into a sheet shape in the forming step S1 and also function as a protective layer that prevents process scratches and conveyance scratches. The upper base material 2 and the lower base material 3 are not particularly limited as long as they can be easily removed from the thick film sheet 10, but process paper such as a release-treated polyester film, for example, release A treated polyethylene terephthalate film, a release-treated polyethylene naphthalate film, or the like can be used. Among these, a polyethylene terephthalate film subjected to a release treatment is preferable.

  The suppressing members 4 and 4 sandwich the both ends of the polymerizable composition 1 in the width direction, and after the molding step S1, the polymerizable composition 1 spreads in the width direction and thins until the polymerization step S2 is completed. This is a member that suppresses the collapse of the shape. The suppressing members 4 and 4 do not damage the rolling roll, the upper base material 2 and the lower base material 3 when being rolled in the forming step S1, and the shape of the polymerizable composition 1 is also maintained after rolling. It is preferable to maintain a shape capable of suppressing collapse. Moreover, when performing thermal polymerization in superposition | polymerization process S2, it is preferable that it can endure the heat required for thermal polymerization. That is, it is preferable that the suppressing members 4 and 4 have flexibility and heat resistance.

  The materials constituting the restraining members 4 and 4 satisfying the above conditions are paper; cotton; hemp; polyolefin; polyimide; polyester such as polyethylene terephthalate and polyethylene naphthalate; fluororesin such as polytetrafluoroethylene; Examples include ether sulfone, polymethylpentene, polyether imide, polysulfone, polyphenylene sulfide, polyamide imide, polyester imide, polyamide, polyarylate, poly (paraphenylene benzobisoxazole), metal, graphite, and the like. Of these, polyester, cotton, polyamide, polyarylate, and poly (paraphenylenebenzobisoxazole) are preferable, polyethylene terephthalate and cotton are more preferable, and cotton is more preferable from the viewpoint of flexibility and availability at low cost. preferable. In addition, the suppression members 4 and 4 may be comprised with 1 type of material, and may be comprised combining the material of multiple types.

The thickness of the restraining members 4 and 4 is T-2 mm or more and T + 3, where T (mm) is the thickness (predetermined thickness) at which the polymerizable composition 1 is molded into a sheet shape by a rolling roll in the molding step S1. 0.5 mm or less, more preferably T-1 mm or more and T + 2 mm or less. By setting the thickness of the suppressing members 4 and 4 within the above range, the thickness NG rate can be easily reduced.
In addition, in FIG. 2 (a), the case where the suppressing members 4 and 4 have a circular cross-sectional shape is shown. However, the polymerizable composition 1 can be prevented from being thinned by spreading in the width direction. If it is, the cross-sectional shape will not be specifically limited.

The angle holding members 5, 5 are arranged between the width direction both ends 3 a, 3 a of the lower base material 3 and the placement surface 7 of the lower base material 3, so that the width direction of the lower base material 3 is set. Both ends 3a, 3a are members that rise from the mounting surface 7 and maintain the angle θ. The angle holding members 5, 5 hold the angle θ between the width direction both ends 3 a, 3 a of the lower substrate 3 and the mounting surface 7, so that the width direction both ends 3 a, 3 a hold the restraining member 4. 4 is restricted to move outward in the width direction (in the direction from the polymerizable composition 1 toward the restraining members 4 and 4), and the shape of the restraining members 4 and 4 becomes thin as the polymerizable composition 1 spreads in the width direction. It becomes possible to reinforce the function of “suppressing collapse”.
The angle θ between the width direction both ends 3a, 3a of the lower substrate 3 and the placement surface 7 is preferably 25 degrees or more and 70 degrees or less, and more preferably 30 degrees or more and 60 degrees or less. By setting the angle θ within the above range, the functions of the suppressing members 4 and 4 can be appropriately reinforced, and the thickness NG ratio can be easily reduced.

In this embodiment, the angle holding members 5 and 5 are arranged after the rolling roll 8, but may be arranged before the rolling roll 8. The angle holding members 5, 5 do not damage the rolling roll 8, the upper base material 2, and the lower base material 3 when being rolled in the forming step S 1, and the restraining members 4, 4 are not damaged after rolling. It is preferable to maintain a shape that can reinforce the function. Moreover, when performing thermal polymerization in superposition | polymerization process S2, it is preferable that it can endure the heat required for thermal polymerization. That is, the angle holding members 5 and 5 preferably have flexibility and heat resistance.
The materials constituting the angle holding members 5 and 5 may be the same as or different from those of the restraining members 4 and 4, but are preferably the same from the viewpoint of handleability and the like. The material which comprises the angle holding members 5 and 5 can mention the thing similar to what was mentioned above as a material which comprises the suppressing members 4 and 4. FIG.

When the thickness (predetermined thickness) for forming the polymerizable composition 1 into a sheet shape by the rolling roll 8 is T (mm) in the forming step S1, the thickness of the angle holding members 5 and 5 is T-2 mm or more, and T + 4 mm or less, more preferably T-1 mm or more and T + 3 mm or less. By setting the thickness of the angle holding members 5 and 5 within the above range, the thickness NG ratio can be easily reduced.
2A shows the case where the cross-sectional shape of the angle holding members 5 and 5 is circular. However, if the function of the restraining members 4 and 4 can be reinforced, the cross-section thereof is used. The shape is not particularly limited.

  The polymerizable composition 1 held by each member described above is subjected to the molding step S1 and the polymerization step S2.

FIG. 3 is a schematic view of the rolling in the forming step S1 as viewed from the side. Molding process S1 can be made into the process rolled with the rolling roll 8, for example in the state hold | maintained by the above-mentioned each member in the polymeric composition 1. FIG. In FIG. 3, the side surfaces of the upper base material 2, the lower base material 3, the suppressing member 4, the angle holding member 5, and the width direction end portion 3 a of the lower base material 3 appear.
The polymerizable composition 1 sandwiched between the upper base material 2 and the lower base material 3 in the upper and lower directions is passed through the upper base material 2 between the upper roll 8a and the lower roll 8b in the direction indicated by the arrow Y. Since it is pressed by the upper roll 8a from above and by the lower roll 8b from the lower side through the lower substrate 3, the polymerizable composition is adjusted by adjusting the interval between the upper roll 8a and the lower roll 8b. 1 can be formed into a sheet having a predetermined thickness. The thickness of the polymerizable composition 1 in the molding step S1 corresponds to the thickness of the thick film sheet after the polymerization step S2.
Although the thickness of the thick film sheet which can be manufactured by this invention is not specifically limited, For example, it is 2 mm or more and about 20 mm or less.
In addition, after passing the upper roll 8a and the lower roll 8b, the angle holding members 5 and 5 are disposed on the lower sides of both side end portions of the lower base material 3.

  Although the method of shape | molding the polymeric composition 1 in predetermined | prescribed thickness in shaping | molding process S1 is not specifically limited, Mass production of a thick film sheet becomes easy by taking the method mentioned above.

  The polymerization step S2 is a step of polymerizing the polymerizable composition 1 after the molding step S1. The polymerization method is not particularly limited, and can be appropriately selected depending on the components contained in the polymerizable composition 1. For example, polymerization can be performed by heating in a heating furnace or the like.

  In the conventional method for producing a thick film sheet, after the polymerizable composition 1 is molded to a predetermined thickness as described above, the shape of the end portion is liable to be collapsed until it is polymerized and cured, resulting in a decrease in yield. It was a factor. In the present invention, as described above, during the period from the molding step S1 to the polymerization step S2, and in the polymerization step S2, the upper and lower sides of the polymerizable composition 1 are formed by the upper base material 2 and the lower base material 3 in the width direction. Are held by the restraining members 4 and 4 having a specific thickness, and the angle θ between the both ends in the width direction of the lower substrate and the mounting surface is set to a specific range by the angle holding members 5 and 5. As a result, it is possible to prevent the polymerizable composition 1 molded to a predetermined thickness from spreading in the width direction and becoming thin and losing its shape, thereby suppressing a decrease in yield.

In the polymerization step S2 in the method for producing a thick film sheet of the present invention, the angle holding members 5 and 5 are preferably arranged until at least the viscosity of the polymerizable composition 1 becomes 150,000 mPa · s or more, and 180000 mPa · s or more. It is more preferable to arrange until it becomes. In the polymerization step S2, by arranging the angle holding members 5 and 5 until the viscosity of the polymerizable composition 1 is equal to or higher than the above lower limit, the viscosity of the polymerizable composition 1 is likely to be deformed depending only on the suppressing members 4 and 4. In the range, since the angle holding members 5 and 5 can obtain the effect of reinforcing the suppressing members 4 and 4, the thickness NG ratio is easily lowered.
In the polymerization step S2, when the viscosity of the polymerizable composition 1 is equal to or higher than the lower limit, the angle holding members 5 and 5 can be removed even during the polymerization reaction. Therefore, when the angle holding members 5 and 5 are used in a loop in the molding step S1 and the polymerization step S2, it is possible to design a production line by shortening the total length of the angle holding members 5 and 5.
FIG. 2 (b) is a cross-sectional view from the same viewpoint as FIG. 2 (a) after the polymerization step S2, and after the viscosity of the polymerizable composition 1 exceeds the above lower limit, the angle holding members 5 and 5 are removed. Then, after that, the polymerization reaction is completed, and a thick film sheet 10 is obtained. By removing the angle holding members 5 and 5, the angle θ becomes smaller than that in FIG. 2A, but since the curing proceeds further after the viscosity of the polymerizable composition 1 becomes equal to or higher than the above lower limit, The thick film sheet 10 having a low thickness NG ratio can be obtained without breaking the shape.
In addition, the manufacturing method of the thick film sheet | seat of this invention does not exclude the form which removes the angle holding members 5 and 5 after superposition | polymerization process S2 is completed.

  FIG. 2C is a cross-sectional view from the same viewpoint as that in FIG. According to the conventional thick film manufacturing method that does not use the restraining members 4, 4 and the angle holding members 5, 5, the deformed portions 21, 21 whose shapes have collapsed are generated at both ends in the width direction. As described above, only the portion sandwiched between the dotted lines becomes the thick film sheet 20 suitable for the product, and the deformed portions 21 and 21 are discarded, so that the yield decreases.

  Hereinafter, the polymerizable composition applicable to the method for producing a thick film sheet of the present invention will be described by taking as an example the case of producing a heat conductive pressure-sensitive adhesive sheet-like molded product (G) as a heat polymerization type thick film sheet. To do.

<Polymerizable composition>
The method for producing a thick film sheet of the present invention can be particularly suitably used when the polymerizable composition is a thermopolymerizable composition that takes time to cure and tends to spread in the width direction and become thin. However, the polymerizable composition is not limited to the thermally polymerizable composition, and may be a photopolymerizable composition.

The polymerizable composition may include a (meth) acrylic acid ester polymer (A1), a (meth) acrylic acid ester monomer (α1), and a polymerization initiator (B1). Moreover, as described later, the polymerizable composition may contain a polyfunctional monomer (C1), a phosphate ester (D1), and a heat conductive filler (E1). In the polymerization step S2, a polymerization reaction of at least the (meth) acrylic acid ester monomer (α1) is performed. By performing the polymerization reaction, the polymer containing the structural unit derived from the (meth) acrylate monomer (α1) is mixed and / or partially bonded to the component of the (meth) acrylate polymer (A1). .
In the present invention, the (meth) acrylic acid ester polymer (A1), the (meth) acrylic acid ester monomer (α1), and the optionally used polyfunctional monomer (C1) are collectively referred to as “(meth)”. It may be referred to as “acrylic resin precursor (P1)”.

  In the present invention, the use ratio of the (meth) acrylic acid ester polymer (A1) and the (meth) acrylic acid ester monomer (α1) is 100% by mass of the total of the (meth) acrylic resin precursor (P1). The (meth) acrylic acid ester polymer (A1) is preferably 15% by mass to 80% by mass, and the (meth) acrylic acid ester monomer (α1) is preferably 20% by mass to 85% by mass. More preferably, the (meth) acrylic acid ester polymer (A1) is 20% by mass or more and 75% by mass or less, and the (meth) acrylic acid ester monomer (α1) is 25% by mass or more and 80% by mass or less. By setting the use ratio of the (meth) acrylic acid ester polymer (A1) and the (meth) acrylic acid ester monomer (α1) within the above range, the thick film sheet can be easily molded.

((Meth) acrylic acid ester polymer (A1))
The (meth) acrylic acid ester polymer (A1) that can be used in the present invention is not particularly limited, but the (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower. It is preferable to contain the unit (a1) and the monomer unit (a2) having an organic acid group.

  The (meth) acrylate monomer (a1m) that gives the unit (a1) of the (meth) acrylate monomer is not particularly limited. For example, ethyl acrylate (the glass transition temperature of the homopolymer is -24 ° C), n-propyl acrylate (-37 ° C), n-butyl acrylate (-54 ° C), sec-butyl acrylate (-22 ° C), n-heptyl acrylate (-60) ° C), n-hexyl acrylate (-61 ° C), n-octyl acrylate (-65 ° C), 2-ethylhexyl acrylate (-50 ° C), n-octyl methacrylate (-25 ° C) (Meth) acrylic acid alkyl ester forming a homopolymer having a glass transition temperature of −20 ° C. or lower, such as n-decyl methacrylate (-49 ° C.); 2-methoxyethyl acrylate ( −50 ° C.), 3-methoxypropyl acrylate (-75 ° C.), 3-methoxybutyl acrylate (-56 ° C.), ethoxymethyl acrylate (-50 ° C.), and the like. (Meth) acrylic acid alkoxyalkyl ester forming a homopolymer having a temperature of 0 ° C. or lower. Among them, (meth) acrylic acid alkyl ester that forms a homopolymer having a glass transition temperature of −20 ° C. or lower, and (meth) acrylic acid alkoxyalkyl ester that forms a homopolymer that has a glass transition temperature of −20 ° C. or lower. (Meth) acrylic acid alkyl ester forming a homopolymer having a glass transition temperature of −20 ° C. or lower is more preferable, and 2-ethylhexyl acrylate is more preferable.

  These (meth) acrylic acid ester monomers (a1m) may be used individually by 1 type, and may use 2 or more types together.

  In the (meth) acrylic acid ester monomer (a1m), the monomer unit (a1) derived therefrom is preferably 80% by mass or more and 99.9% by mass in the (meth) acrylic acid ester polymer (A1). Hereinafter, it is used for polymerization in such an amount that it is more preferably 85% by mass or more and 99.5% by mass or less. When the amount of the (meth) acrylic acid ester monomer (a1m) is within the above range, it becomes easy to keep the viscosity of the polymerizable composition at the time of polymerization in an appropriate range.

  Next, the monomer unit (a2) having an organic acid group will be described. The monomer (a2m) that gives the monomer unit (a2) having an organic acid group is not particularly limited, but representative examples thereof include organic acid groups such as a carboxyl group, an acid anhydride group, and a sulfonic acid group. The monomer which has can be mentioned. In addition to these, monomers containing sulfenic acid groups, sulfinic acid groups, phosphoric acid groups, and the like can also be used.

  Specific examples of the monomer having a carboxyl group include, for example, α, β-ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and α, such as itaconic acid, maleic acid, and fumaric acid. In addition to β-ethylenically unsaturated polyvalent carboxylic acid, α, β-ethylenically unsaturated polyvalent carboxylic acid partial esters such as monomethyl itaconate, monobutyl maleate and monopropyl fumarate can be used. Moreover, what has group which can be induced | guided | derived to a carboxyl group by hydrolysis etc., such as maleic anhydride and itaconic anhydride, can be used similarly.

  Specific examples of the monomer having a sulfonic acid group include allyl sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, styrene sulfonic acid, α, β-unsaturated sulfonic acid such as acrylamide-2-methylpropane sulfonic acid, And salts thereof.

  As the monomer (a2m), among the monomers having an organic acid group exemplified above, a monomer having a carboxyl group is more preferable, and an α, β-ethylenically unsaturated monocarboxylic acid is more preferable. (Meth) acrylic acid is particularly preferred. These monomers are industrially inexpensive and can be easily obtained, have good copolymerizability with other monomer components, and are preferable in terms of productivity. In addition, a monomer (a2m) may be used individually by 1 type, and may use 2 or more types together.

  In the monomer (a2m) having an organic acid group, the monomer unit (a2) derived from the monomer unit (a2) is preferably 0.1% by mass or more and 20% by mass or less in the (meth) acrylic acid ester polymer (A1). More preferably, it is used for the polymerization in such an amount that it is 0.5 to 15% by mass. When the usage-amount of the monomer (a2m) which has an organic acid group exists in the said range, it will become easy to maintain the viscosity of the polymeric composition at the time of superposition | polymerization in an appropriate range.

  The monomer unit (a2) having an organic acid group is introduced into the (meth) acrylic acid ester polymer (A1) by polymerization of the monomer (a2m) having an organic acid group as described above. Although it is simple and preferable to perform, an organic acid group may be introduced by a known polymer reaction after the (meth) acrylic acid ester polymer (A1) is formed.

  The (meth) acrylic acid ester polymer (A1) may contain a monomer unit (a3) derived from a monomer (a3m) having a functional group other than an organic acid group. Examples of the functional group other than the organic acid group include a hydroxyl group, an amino group, an amide group, an epoxy group, and a mercapto group.

  Examples of the monomer having a hydroxyl group include (meth) acrylic acid hydroxyalkyl esters such as (meth) acrylic acid 2-hydroxyethyl and (meth) acrylic acid 3-hydroxypropyl.

  Examples of the monomer having an amino group include N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and aminostyrene.

  Examples of monomers having an amide group include α, β-ethylenically unsaturated carboxylic acid amide monomers such as acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, and N, N-dimethylacrylamide. Can be mentioned.

  Examples of the monomer having an epoxy group include glycidyl (meth) acrylate and allyl glycidyl ether.

  As the monomer (a3m) having a functional group other than the organic acid group, one type may be used alone, or two or more types may be used in combination.

  In the monomer (a3m) having a functional group other than these organic acid groups, the monomer unit (a3) derived therefrom is 10% by mass or less in the (meth) acrylate polymer (A1). It is preferable to use it for polymerization in such an amount. By using the monomer (a3m) of 10% by mass or less, it becomes easy to keep the viscosity of the polymerizable composition at the time of polymerization in an appropriate range.

  The (meth) acrylic acid ester polymer (A1) has a (meth) acrylic acid ester monomer unit (a1) that forms a homopolymer having the above-described glass transition temperature of −20 ° C. or lower, and an organic acid group. In addition to the monomer unit (a2) and the monomer unit (a3) having a functional group other than an organic acid group, a monomer derived from the monomer (a4m) copolymerizable with the above-described monomer. The monomer unit (a4) may be contained.

  The monomer (a4m) is not particularly limited, and specific examples thereof include (meth) acrylate monomers other than the (meth) acrylate monomer (a1m), α, β-ethylenic monomers. Saturated polyvalent carboxylic acid complete ester, alkenyl aromatic monomer, vinyl cyanide monomer, carboxylic acid unsaturated alcohol ester, olefin monomer and the like can be mentioned.

  Specific examples of the (meth) acrylate monomer other than the (meth) acrylate monomer (a1m) include methyl acrylate (homopolymer having a glass transition temperature of 10 ° C.), methyl methacrylate. (105 ° C.), ethyl methacrylate (63 ° C.), n-propyl methacrylate (25 ° C.), and n-butyl methacrylate (20 ° C.).

  Specific examples of the α, β-ethylenically unsaturated polyvalent carboxylic acid complete ester include dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, dimethyl itaconate and the like.

  Specific examples of the alkenyl aromatic monomer include styrene, α-methylstyrene, methyl α-methylstyrene, vinyltoluene and the like.

  Specific examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile and the like.

  Specific examples of the carboxylic acid unsaturated alcohol ester monomer include vinyl acetate.

  Specific examples of the olefin monomer include ethylene, propylene, butene, pentene and the like.

  A monomer (a4m) may be used individually by 1 type, and may use 2 or more types together.

  In the monomer (a4m), the amount of the monomer unit (a4) derived therefrom is preferably 10% by mass or less, more preferably 5% by mass or less in the (meth) acrylate polymer (A1). It is subjected to polymerization in such an amount.

  The (meth) acrylic acid ester polymer (A1) has a (meth) acrylic acid ester monomer (a1m) and an organic acid group, which form the homopolymer having a glass transition temperature of −20 ° C. or lower. Monomer (a2m), a monomer containing a functional group other than an organic acid group (a3m) used as necessary, and a monomer copolymerizable with these monomers used as needed It can be particularly suitably obtained by copolymerizing the monomer (a4m).

  The polymerization method for obtaining the (meth) acrylic acid ester polymer (A1) is not particularly limited, and may be any of solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, and the like, or any other method. . However, among these polymerization methods, solution polymerization is preferable, and among them, solution polymerization using a carboxylic acid ester such as ethyl acetate or ethyl lactate or an aromatic solvent such as benzene, toluene or xylene is more preferable. In the polymerization, the monomer may be added in portions to the polymerization reaction vessel, but it is preferable to add the whole amount at once. The method for initiating the polymerization is not particularly limited, but it is preferable to use a thermal polymerization initiator as the polymerization initiator. The thermal polymerization initiator is not particularly limited, and for example, a peroxide polymerization initiator or an azo compound polymerization initiator can be used.

  Peroxide polymerization initiators include hydroperoxides such as t-butyl hydroperoxide, peroxides such as benzoyl peroxide and cyclohexanone peroxide, and persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate. Can be mentioned. These peroxides can also be used as a redox catalyst in appropriate combination with a reducing agent.

  As the azo compound polymerization initiator, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile) And so on.

  Although the usage-amount of a polymerization initiator is not specifically limited, It is preferable that it is the range of 0.01 to 50 mass parts with respect to 100 mass parts of monomers.

  Other polymerization conditions (polymerization temperature, pressure, stirring conditions, etc.) of these monomers are not particularly limited.

  After completion of the polymerization reaction, the obtained polymer is separated from the polymerization medium as necessary. The separation method is not particularly limited. For example, in the case of solution polymerization, the (meth) acrylic acid ester polymer (A1) can be obtained by placing the polymerization solution under reduced pressure and distilling off the polymerization solvent.

  The weight average molecular weight (Mw) of the (meth) acrylic acid ester polymer (A1) is measured by gel permeation chromatography (GPC method) and may be in the range of 1,000 to 1,000,000 in terms of standard polystyrene. Preferably, it is in the range of 100,000 or more and 500,000 or less. The weight average molecular weight of the (meth) acrylic acid ester polymer (A1) can be controlled by appropriately adjusting the amount of the polymerization initiator used in the polymerization and the amount of the chain transfer agent.

((Meth) acrylic acid ester monomer (α1))
The (meth) acrylate monomer (α1) is not particularly limited as long as it contains a (meth) acrylate monomer, but forms a homopolymer having a glass transition temperature of −20 ° C. or lower. It is preferable to contain the (meth) acrylic acid ester monomer (a5m).

  As an example of the (meth) acrylic acid ester monomer (a5m) that forms a homopolymer having a glass transition temperature of −20 ° C. or lower, it is used for the synthesis of a (meth) acrylic acid ester polymer (A1) (meta ) The same (meth) acrylate monomer as the acrylate monomer (a1m) can be mentioned. A (meth) acrylic acid ester monomer (a5m) may be used individually by 1 type, and may use 2 or more types together.

  The ratio of the (meth) acrylate monomer (a5m) in the (meth) acrylate monomer (α1) is preferably 50% by mass to 100% by mass, more preferably 75% by mass to 100% by mass. It is as follows. By setting the ratio of the (meth) acrylic acid ester monomer (a5m) in the (meth) acrylic acid ester monomer (α1) to the above range, a thick film sheet excellent in pressure-sensitive adhesiveness and flexibility is obtained. It becomes easy.

  The (meth) acrylic acid ester monomer (α1) is a (meth) acrylic acid ester monomer (a5m) that forms a homopolymer having a glass transition temperature of −20 ° C. or lower. It is good also as a mixture of the monomer (a6m) which has a polymerizable organic acid group.

  Examples of the monomer (a6m) include monomers having an organic acid group similar to those exemplified as the monomer (a2m) used for the synthesis of the (meth) acrylic acid ester polymer (A1). be able to. A monomer (a6m) may be used individually by 1 type, and may use 2 or more types together.

  The ratio of the monomer (a6m) in the (meth) acrylic acid ester monomer (α1) is preferably 30% by mass or less, and more preferably 10% by mass or less. By setting the ratio of the monomer (a6m) in the (meth) acrylic acid ester monomer (α1) to the above range, it becomes easy to obtain a thick film sheet excellent in pressure-sensitive adhesiveness and flexibility.

  The (meth) acrylic acid ester monomer (α1), in addition to the (meth) acrylic acid ester monomer (a5m) and the monomer (a6m) having an organic acid group that can be optionally copolymerized, It is good also as a mixture containing the monomer (a7m) copolymerizable with these.

  Examples of the monomer (a7m) include the monomer (a3m) used for the synthesis of the (meth) acrylic acid ester polymer (A1) and the same amount as those exemplified as the monomer (a4m). The body can be mentioned. A monomer (a7m) may be used individually by 1 type, and may use 2 or more types together.

  The ratio of the monomer (a7m) in the (meth) acrylic acid ester monomer (α1) is preferably 20% by mass or less, and more preferably 15% by mass or less.

(Polymerization initiator (B1))
In the polymerization step S2, it is preferable to use a polymerization initiator (B1) in order to accelerate the polymerization reaction. Examples of the polymerization initiator (B1) include a photopolymerization initiator, an azo thermal polymerization initiator, and an organic peroxide thermal polymerization initiator. However, from the viewpoint of effectively imparting adhesive force to the resulting thick film sheet, it is preferable to use an organic peroxide thermal polymerization initiator.

  Various known photopolymerization initiators can be used as the photopolymerization initiator. Of these, acylphosphine oxide compounds are preferred. Examples of the acylphosphine oxide compound that is a preferred photopolymerization initiator include bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

  As the azo thermal polymerization initiator, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile) ) And the like.

  As the organic peroxide thermal polymerization initiator, hydroperoxide such as t-butyl hydroperoxide, benzoyl peroxide, cyclohexanone peroxide, 1,6-bis (t-butylperoxycarbonyloxy) hexane, 1,1-bis ( and a peroxide such as t-butylperoxy) -3,3,5-trimethylcyclohexanone. However, those that do not release volatile substances that cause odor during thermal decomposition are preferred. Among organic peroxide thermal polymerization initiators, those having a 1-minute half-life temperature of 100 ° C. or more and 170 ° C. or less are preferable.

The amount of the polymerization initiator (B1) used is preferably 0.01 parts by mass or more and 10 parts by mass or less with respect to a total of 100 parts by mass of the (meth) acrylic resin precursor (P1). More preferably, it is more than 5 parts by mass and more preferably less than 0.3 part by mass and less than 2 parts by mass.
By making the usage-amount of a polymerization initiator (B1) into the said range, it becomes easy to make the polymerization conversion rate of a (meth) acrylic acid ester monomer ((alpha) 1) into an appropriate range, and a monomer odor remains on a thick film sheet. It becomes easy to prevent this.
The polymerization conversion rate of the (meth) acrylic acid ester monomer (α1) is preferably 95% by mass or more. When the polymerization conversion rate of the (meth) acrylic acid ester monomer (α1) is 95% by mass or more, it becomes easy to prevent the monomer odor from remaining on the thick film sheet.
Moreover, by setting the usage-amount of a polymerization initiator (B1) to the said range, a polymerization reaction advances too much and the thick film sheet 10 does not become a smooth sheet form, but it says that an unevenness | corrugation and a pinhole generate | occur | produce on the surface. It becomes easy to prevent the situation.

(Polyfunctional monomer (C1))
In the present invention, the polymerizable composition may contain a polyfunctional monomer (C1). Usually, at the time of polymerization such as radical thermal polymerization, a certain degree of crosslinking reaction proceeds without using the polyfunctional monomer (C1). However, a polyfunctional monomer (C1) may be used in order to form a desired amount of a crosslinked structure more reliably.

  As the polyfunctional monomer (C1) that can be used in the present invention, a monomer that is copolymerizable with the monomer contained in the (meth) acrylic acid ester monomer (α1) is used. Moreover, the polyfunctional monomer (C1) has a plurality of polymerizable unsaturated bonds, and preferably has the unsaturated bond at the terminal. By using such a polyfunctional monomer (C1), intramolecular and / or intermolecular crosslinking can be introduced into the copolymer, and the cohesive force as a pressure-sensitive adhesive can be enhanced.

  Examples of the polyfunctional monomer (C1) include 1,6-hexanediol di (meth) acrylate, 1,2-ethylene glycol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, and polyethylene. Glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ditri Multifunctional (meth) acrylates such as methylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and 2,4-bis (tri Other substituted triazines, such as Roromechiru) -6-p-methoxystyrene-5-triazine, etc. monoethylenically unsaturated aromatic ketones such as 4-acryloxy benzophenone can be used. Polyfunctional (meth) acrylates are preferred, and pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth) acrylate are more preferred. A polyfunctional monomer (C1) may be used individually by 1 type, and may use 2 or more types together.

  The amount of the polyfunctional monomer (C1) used is preferably 10% by mass or less, preferably 5% by mass or less, with the total of the (meth) acrylic resin precursor (P1) being 100% by mass. More preferred. By making the usage-amount of a polyfunctional monomer (C1) into the said range, it becomes easy to provide suitable cohesion force to a thick film sheet.

<Phosphate ester (D1)>
The polymerizable composition may contain a phosphate ester (D1). By containing the phosphate ester (D1), it becomes easy to impart excellent flame retardancy to the thick film sheet.

  The phosphate ester (D1) used in the present invention preferably has a viscosity at 25 ° C. of 3000 mPa · s or more. By making the viscosity of phosphoric acid ester (D1) into the said range, the deterioration of the moldability of a thick film sheet can be suppressed. In the present invention, the “viscosity” of the phosphate ester (D1) means the viscosity measured by the method described below.

(Method for measuring viscosity of phosphate ester (D1))
The viscosity of the phosphoric acid ester (D1) is measured using a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd.) according to the following procedure.
(1) Weigh 300 ml of phosphate ester in a normal temperature environment and place it in a 500 ml container.
(2) Stirring rotor No. Select one from 1, 2, 3, 4, 5, 6, and 7 and attach to the viscometer.
(3) The container containing the phosphate ester is placed on the viscometer, and the rotor is submerged in the condensed phosphate ester in the container. At this time, the dent which becomes a mark of a rotor sinks so that it may just come to the liquid interface of phosphate ester.
(4) The rotation speed is selected from 20, 10, 4, and 2.
(5) Turn on the stirring switch and read the value after 1 minute.
(6) The value obtained by multiplying the read numerical value by the coefficient A is the viscosity [mPa · s].
The coefficient A is the selected rotor No. as shown in Table 1 below. And the number of revolutions.

  Moreover, it is preferable that the phosphate ester (D1) used for this invention is always a liquid in the temperature range of 15 degreeC or more and 100 degrees C or less under atmospheric pressure. If the phosphate ester (D1) is liquid when mixed, the workability is good and it becomes easy to form a thick film sheet. When forming the thick film sheet containing the phosphate ester (D1), it is preferable to mix the substances constituting the polymerizable composition that is the precursor of the thick film sheet in an environment of 15 ° C. or more and 100 ° C. or less. . By setting the temperature at the time of mixing in the above range, the glass transition temperature of the polymerizable composition is set to be equal to or higher, and it is easy to prevent volatilization of the monomer or the like contained in the polymerizable composition or the start of the polymerization reaction. , Environmental performance and workability can be improved.

  In the present invention, either a condensed phosphate ester or a non-condensed phosphate ester can be used as the phosphate ester (D1). As used herein, “condensed phosphate ester” means one having a plurality of phosphate ester moieties in one molecule, and “non-condensed phosphate ester” means one phosphate ester moiety in one molecule. It means something that exists only. Specific examples of the phosphate ester (D1) that satisfies the conditions described so far are listed below.

  Specific examples of the condensed phosphate ester include aromatic condensed phosphate esters such as 1,3-phenylene bis (diphenyl phosphate), bisphenol A bis (diphenyl phosphate), resorcinol bis (diphenyl phosphate); polyoxyalkylene bisdichloroalkyl And halogen-containing condensed phosphates such as phosphates; non-aromatic non-halogen-based condensed phosphates; Among these, aromatic condensed phosphates are preferred because of their relatively low specific gravity, no danger of releasing harmful substances (such as halogens), and availability, and 1,3-phenylenebis (diphenyl phosphate). ), Bisphenol A bis (diphenyl phosphate) is more preferred.

  Specific examples of the non-condensed phosphate ester include aromatics such as triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-xylenyl phosphate, 2-ethylhexyl diphenyl phosphate And phosphoric acid esters; halogen-containing phosphoric acid esters such as tris (β-chloropropyl) phosphate, trisdichloropropylphosphate, tris (tribromoneopentyl) phosphate; Of these, aromatic phosphates are preferred because no harmful substances (such as halogen) are generated.

  A phosphate ester (D1) may be used individually by 1 type, and may use 2 or more types together.

  When using the phosphoric ester (D1) for the thick film sheet, the amount is preferably 120 parts by mass or less, and 100 parts by mass or less, with the total of the (meth) acrylic resin precursor (P1) being 100 parts by mass. It is more preferable that By making content of phosphate ester (D1) into the said range, it becomes easy to maintain the pressure-sensitive adhesiveness of a thick film sheet.

<Thermal conductive filler (E1)>
The polymerizable composition may contain a heat conductive filler (E1). The thermally conductive filler (E1) used in the present invention is an inorganic compound that can improve the thermal conductivity of the thick film sheet when added, and has a thermal conductivity of 0.3 W / m · K or more.

  Specific examples of the thermally conductive filler (E1) include metal hydroxides such as aluminum hydroxide, gallium hydroxide, indium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide; aluminum oxide ( Alumina), metal oxides such as magnesium oxide and zinc oxide; metal carbonates such as calcium carbonate and aluminum carbonate; metal nitrides such as boron nitride and aluminum nitride; zinc borate hydrate; kaolin clay; calcium aluminate water Examples thereof include: Japanese; Dosonite; Silica; Expanded graphite powder, artificial graphite, carbon black, carbon fiber, and other carbon-containing conductive fillers. Of these, metal hydroxides and metal oxides are preferred, metal hydroxides are more preferred, aluminum hydroxide and aluminum oxide (alumina) are more preferred, and aluminum hydroxide is even more preferred. A heat conductive filler (E1) may be used individually by 1 type, and may use 2 or more types together.

  The amount of the thermally conductive filler (E1) used for the thick film sheet is 1100 parts by mass or less and 1050 parts by mass or less with respect to a total of 100 parts by mass of the (meth) acrylic resin precursor (P1). Preferably, it is 1000 parts by mass or less. By making content of a heat conductive filler (E1) below the said upper limit, it becomes easy to suppress that the viscosity of the polymeric composition which is a precursor of a thick film sheet becomes high too much. Therefore, it is possible to prevent a situation in which it becomes difficult to form the thick film sheet, or even if the thick film sheet can be formed, the hardness of the thick film sheet increases and the shape followability (adhesion to the adherend) decreases. .

<Other additives>
Various known additives can be added to the thick film sheet in addition to the substances described so far as long as required performances such as pressure-sensitive adhesiveness and thermal conductivity can be satisfied.
Known additives include foaming agents (including foaming aids); glass fibers; thermally conductive inorganic compounds such as PITCH carbon fibers excluding the above-described thermally conductive filler (E1); external crosslinking agents; Pigments such as titanium dioxide; other fillers such as clay; nanoparticles such as fullerenes and carbon nanotubes; antioxidants such as polyphenols, hydroquinones and hindered amines; thickeners such as acrylic polymer particles; be able to.

  When manufacturing a thick film sheet as described above (when it contains a heat conductive filler (E1), it becomes a heat conductive pressure-sensitive adhesive sheet-like molded body (G)), first, each of the above-described items The polymerizable composition is prepared by mixing the substances. Thereafter, as described above, the polymerizable composition is subjected to the forming step S1 while being held by each member as shown in FIGS. 1 and 2A, and is formed into a sheet having a predetermined thickness. . Thereafter, in the polymerization step S2, a polymerization reaction of the polymerizable composition is performed. When performing the said polymerization reaction, it is preferable to heat. For the heating, for example, hot air, an electric heater, infrared rays, or the like can be used. The heating temperature at this time is preferably a temperature at which the polymerization initiator is efficiently decomposed and the polymerization reaction of the polymerizable composition proceeds easily. The temperature range varies depending on the type of polymerization initiator used, but is preferably 100 ° C. or higher and 200 ° C. or lower, and more preferably 130 ° C. or higher and 180 ° C. or lower.

  According to the method for producing a thick film sheet of the present invention, even when a polymerizable composition having a relatively low viscosity is used as a raw material, a thick film sheet in which the shape of the end portion in the width direction does not collapse is produced. Can do. For example, the method for producing a thick film sheet of the present invention can be particularly suitably applied when a polymerizable composition having a viscosity at 40 ° C. of 1000 mPa · s or more and less than 180000 mPa · s is used as a raw material.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the examples. The “parts” and “%” used here are based on mass unless otherwise specified.

<Thickness NG ratio>
Using a thickness meter (manufactured by TOYOSEIKI, a digital thickness gauge) in increments of 5 mm from the end in the width direction of the thick film sheet produced as described later, from the one end in the width direction of the thick film sheet to the other The thickness was measured to the end of, the thickness NG ratio was calculated by the following formula (1), and the result is shown in Table 3. In addition, when the thickness NG ratio is less than 15%, a decrease in yield is suppressed and productivity is excellent.
Thickness NG ratio [%] = 100 × B / (A + B) (1)
A: Total weight of the sheet portion having a thickness of ± 10% in the center in the width direction B: Total weight of the sheet portion other than A

<Production of thick film sheet>
Example 1

  Two substrates (an upper substrate and a lower substrate) obtained by cutting a polyethylene terephthalate film (hereinafter sometimes referred to as “release PET film”) having a thickness of 75 μm into a 150 mm × 150 mm square. ) And a marking line was drawn so that a square of 100 mm × 100 mm was formed at a position of 25 mm from four sides of one substrate (lower substrate). Among the square marking lines, a sheet having a width of 3 mm (manufactured by Zeon Kasei Co., Ltd., trade name “TIMS-ZS1B2”)) was attached along the front and rear marking lines, and the sheet was fixed to the lower substrate. Next, on the left and right marking lines, a restraining member (tako yarn manufactured by Yutaka Make Co., Ltd.), which is a cotton thread (tako thread) having a circular shape with a cross-sectional diameter of 3 mm (corresponding to a thickness of 3 mm), was arranged.

  A reactor was charged with 100 parts of a monomer mixture composed of 94% 2-ethylhexyl acrylate and 6% acrylic acid, 0.03 parts 2,2′-azobisisobutyronitrile and 700 parts ethyl acetate. Then, after substitution with nitrogen, a polymerization reaction was carried out at 80 ° C. for 6 hours. The polymerization conversion rate was 97%. The obtained polymer was dried under reduced pressure to evaporate ethyl acetate to obtain a viscous solid (meth) acrylic acid ester polymer (A1-1). The weight average molecular weight (Mw) of the (meth) acrylic acid ester polymer (A1-1) was 270,000, and the weight average molecular weight (Mw) / number average molecular weight (Mn) was 3.1. The weight average molecular weight (Mw) and the number average molecular weight (Mn) were determined in terms of standard polystyrene by gel permeation chromatography using tetrahydrofuran as an eluent.

  Next, 29 parts of 2-ethylhexyl acrylate (2EHA) and an organic peroxide thermal polymerization initiator (1,6-bis (t-butylperoxycarbonyloxy) hexane (1 minute half-life temperature is 150 ° C.). )) 1 part was weighed with an electronic balance, and these were mixed with 70 parts of the (meth) acrylic acid ester polymer (A1-1). For the mixing, a thermostatic bath (manufactured by Toki Sangyo Co., Ltd., trade name “Viscomate 150III”) and Hobart mixer (manufactured by Kodaira Seisakusho, trade name “ACM-5LVT type”, capacity: 5 L) were used. The temperature control of the Hobart container was set to 50 ° C., vacuum (−0.1 MPaG) was performed, the rotation speed scale was set to 3, and the mixture was stirred for 30 minutes to obtain a polymerizable composition A.

  60 g of the sol of the polymerizable composition A is hung on a substantially square surface surrounded by the left and right restraining members and the upper and lower sheets on the lower substrate, and the sol of the polymerizable composition A is dropped. The upper base material was put on the polymerizable composition A so as to be sandwiched with the lower base material. Thus, what rolls up and down the said polymeric composition A by the base material of a mold release PET film and the width direction both ends by the suppression member (henceforth only a laminated body) is roll. The polymerizable composition A was molded into a sheet having a thickness of 3 mm by passing between two rolls adjusted to a distance of 3.15 mm. Next, fold the both ends of the lower substrate so that the angle θ between the mounting surface and both ends of the lower substrate is 45 degrees along the left and right marking lines, An angle holding member (manufactured by Yutaka Make Co., Ltd.), which is a circular thread with a diameter of 3 mm (equivalent to a thickness of 3 mm) under both end portions of the lower base so as to hold Tako thread) was placed. Thereafter, from the upper base material side of the laminate, the sol temperature is adjusted to 80 ° C. with a dryer, and the angle holding material is removed when the sol viscosity becomes 180,000 mPa · s, and then in an oven at 120 ° C. Heated for 30 minutes. As a result, a thick film sheet was obtained in which the upper and lower sides were sandwiched by the release PET film base and the width direction both ends by the suppressing member. The polymerization conversion rate of all monomers was calculated from the amount of residual monomers in the thick film sheet, and found to be 99.9%.

(Examples 2 to 8 and Comparative Examples 1 to 7)
In place of the polymerizable composition A in Table 2 used in Example 1, the polymerizable composition B to D were used, and the angle θ and the thickness of the suppressing member were changed as shown in Table 3. Except for the above, the sheets according to Examples 2 to 8 and the sheets according to Comparative Examples 1 to 7 were produced in the same manner as Example 1.
The polymerizable composition B used in Example 6 was aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., trade name “BF-083”, average particle size: 8 μm, BET specific surface area: as the heat conductive filler (E1). 0.8 m ² / g). The polymerizable composition C used in Example 7 and the polymerizable composition D used in Example 8 were prepared by mixing pentaerythritol triacrylate, pentaerythritol tetraacrylate and pentaerythritol diacrylate in a ratio of 60: 35: 5. Polyfunctional monomer (C1) (light acrylate PE-3A, manufactured by Kyoeisha Chemical Co., Ltd.), phosphoric ester (D1) (manufactured by Ajinomoto Fine-Techno Co., Ltd., trade name “Reophos 65”, compound name, which is a crosslinking agent Alumina (trade name “AL-47-H” manufactured by Showa Denko KK) together with aluminum hydroxide contained in the polymerizable composition B as a “triaryl isopropylated product” and a thermally conductive filler (E1) Average particle size: 3 μm, BET specific surface area: 1.1 m ² / g).

As shown in Table 3, all of the thick film sheets according to Examples 1 to 8 had a thickness NG ratio of less than 15%, suppressed a decrease in yield, and were excellent in productivity.
On the other hand, the thick film sheet according to Comparative Example 1 that did not use the angle holding member and the suppressing member, the thick film sheet according to Comparative Examples 2 and 3 in which the angle θ is outside the range of the present invention, and the comparison that did not use the angle holding member In the thick film sheet according to Example 4, the thick film sheet according to Comparative Example 5 in which the suppressing member was not used, and the thick film sheet according to Comparative Examples 6 and 7 in which the thickness of the suppressing member was outside the scope of the present invention, Was over 15%, yield was lowered, and productivity was inferior.

DESCRIPTION OF SYMBOLS 1 Polymerizable composition 2 Upper side base material 3 Lower side base material 3a Width direction (both) edge part 4 Control member 5 Angle holding member 6 Free roll 7 Mounting surface 8 Roll roll 8a Upper roll 8b Lower roll 10, 20 Thick film Sheet 21 shape collapse part

Claims (3)

A method for producing a thick film sheet,
A molding step of molding the polymerizable composition into a sheet having a predetermined thickness by a rolling roll;
A polymerization step of polymerizing the polymerizable composition after the molding step,
The polymerizable composition is sandwiched between the upper base material and the lower base material on the upper and lower sides, and both ends in the width direction are sandwiched between the suppressing members,
The thickness of the suppression member is (the predetermined thickness-2 mm) or more and (the predetermined thickness + 3.5 mm) or less,
An angle holding member is disposed between the width direction both ends of the lower substrate and the mounting surface of the lower substrate, and the width direction both ends of the lower substrate are described above by the angle holding member. A method for producing a thick film sheet, characterized in that an angle θ formed between both end portions in the width direction of the substrate formed by rising from a placement surface and the placement surface is 25 degrees or more and 70 degrees or less.   In the said superposition | polymerization process, the said angle holding member is a manufacturing method of the thick film sheet of Claim 1 arrange | positioned until the viscosity of the said polymeric composition becomes 150000 mPa * s or more.   The said polymeric composition contains (meth) acrylic acid ester polymer (A1), (meth) acrylic acid ester monomer ((alpha) 1), and a polymerization initiator (B1) of Claim 1 or 2. A method for producing a thick film sheet.