JP4187517B2 - Belt-type continuous plate making apparatus and method for producing plate-like polymer - Google Patents

Description

【００８１】
表１に示す結果から明らかなように、板状製品１（参考例１）の中厚形状Ｔは低い値で導光板用途に十分なフラット性を有していた。さらに、板状製品２（実施例２）の中厚形状Ｔはより低い値であり、板状製品３（実施例３）の中厚形状Ｔはそれよりもさらに低い値であった。
【００８２】
板状製品４（参考例２）も同様に、その中厚形状Ｔは低い値で導光板用途に十分なフラット性を有していた。また、板状製品５、６、７、８（実施例５）の中厚形状Ｔは何れも低い値であり、特に板状製品５は極めて高いフラット性を有していた。
【００８３】
板状製品９、１０、１１（実施例６）の中厚形状Ｔは何れも低い値であった。このことから、運転時の連続的な生産速度を変更しても板状製品の高いフラット性は変わらない事が分かる。
【００８４】
板状製品１２（比較例１）の中厚形状Ｔは高い値であり、板厚精度の悪い板であった。また、板状製品１３（参考例３）の中厚形状Ｔの値は板状製品１（参考例１）に比べて高く、板厚精度が優れた板ではなかったが、比較例１の板よりは優れていた。また、板状製品１４（参考例４）の中厚形状Ｔは板状製品４（参考例２）のそれとほぼ同等であり、加熱ゾーンにおける下側ロールへのクラウンロールの導入数が総数の４％以下であったため効果は大きいとはいえなかった。
【００８５】
【発明の効果】
以上説明したとおり、本発明によれば、装置のベルト幅に関係無く、極めて高い板厚精度を有する板状重合物を製造できるベルト式連続製板装置、および板状重合物の製造方法を提供できる。
【図面の簡単な説明】
【図１】本発明のベルト式連続製板装置の一例を示す模式的断面図である。
【図２】図１の下側ロール４'に用いるクラウンロールの一例を示す模式図である。
【図３】（ａ）（ｂ）は、上側ロールにフラットロール、下側ロールにクラウンロールを用いた線荷重調整機構を有するロール対を例示する模式的断面図であり、両図はバネの圧縮長を変更した２つの状態を表している。
【図４】（ａ）（ｂ）は、上側ロールにフラットロール、下側ロールにクラウンロールを用いた線荷重調整機構を有するロール対を例示する模式的断面図であり、両図は引張りバネの延伸長を変更した２つの状態を表している。
【図５】実施例および比較例における評価の際の板サイズを示す斜視図である。
【図６】実施例および比較例における評価の際の板サイズを示す斜視図である。
【符号の説明】
１、１' エンドレスベルト
２、２' 主プーリ
３、３' 主プーリ
４、４' 上下ロール対
５ 定量ポンプ
６ ノズル
７ ガスケット
８ 温水スプレー
９、９' 遠赤外線ヒータ
１０ 板状製品
１１ フレーム
１２ 側壁
１３ 支持棒
１４ バネ
１５ 台座、または梁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a belt-type continuous plate making apparatus for continuously producing a plate-like product (plate-like polymer) by continuously polymerizing a polymerizable raw material, and a method for producing a plate-like polymer using this apparatus.
[0002]
[Prior art]
Plate polymers obtained using methyl methacrylate as a main raw material are used in a wide range of fields such as signboards, building materials, sanitary applications such as buses, lighting applications, etc., taking advantage of their excellent properties. In recent years, it has also been used as a light guide plate for a display device such as a liquid crystal display, and the demand for IT has been rapidly increasing due to the global trend toward IT.
[0003]
Of course, such a light guide plate is required to have high optical properties as a material. However, in order to prevent the luminance distribution of the display, the dimensional accuracy in the thickness direction (hereinafter referred to as “thickness direction”) is extremely high compared to conventional applications. (Sometimes abbreviated as “plate thickness accuracy”).
[0004]
On the other hand, there is a continuous casting method using a belt type continuous plate making apparatus as a method for continuously producing a plate-like polymer. This belt-type continuous plate-making apparatus supplies a polymerizable raw material from one end between two opposite endless belts that run at the same speed in the horizontal direction, and is heated together with the movement of the endless belt. This is an apparatus for polymerizing by a method and obtaining a plate-like polymer from the other. In such a device, as a belt surface holding mechanism, a plurality of upper and lower roll pairs whose respective axes are orthogonal to the belt traveling direction are arranged along the belt traveling direction. The plate thickness accuracy in the width direction of the plate-shaped polymer is determined by the roll generated by the rigidity of the roll body of the upper and lower roll pairs, the arrangement interval of the upper and lower roll pairs in the belt running direction, and the linear load applied from the upper roll to the belt surface. It is determined by the conditions such as the fluid pressure in the raw material during the process and the tension of the endless belt.
[0005]
As a method for improving the plate thickness accuracy in the width direction in the belt type continuous plate making apparatus, for example, as shown in Patent Document 1, paying attention to the effect of spreading the belt due to the raw material hydraulic pressure between a pair of upper and lower rolls, the roll Designed with high rigidity and a low rigidity shaft, the shaft is deformed preferentially to follow the volume shrinkage of the liquid material, thereby maintaining the linear load on the belt surface and increasing the thickness accuracy. There are ways to improve it.
[0006]
However, when the plate thickness accuracy is entrusted to ensure the rigidity of the roll body as in this method, the plate thickness accuracy is not necessarily improved in a belt type continuous plate making apparatus having a wide endless belt.
[0007]
The reason is as follows. That is, as can be seen from equation (2) described later, generally, the amount of deflection of the roll body when a uniform load in the width direction is applied to the roll body by the internal liquid pressure of the raw material is 4 of the width of the roll body. It is proportional to the power. Therefore, when the endless belt becomes wide, the medium thickness shape of the plate-like product generated by the transfer of the roll body bending shape becomes extreme. Moreover, in order to further increase the rigidity of the roll body, it is necessary to increase the roll body diameter, but if the roll body diameter is designed to be large, it is inevitably necessary to widen the roll arrangement interval in the belt running direction, This promotes the bending of the endless belt between the roll pairs, and eventually reduces the thickness accuracy of the product. Furthermore, if the distance between the upper and lower roll pairs is too wide, the risk of the raw material liquid leaking outside the gasket increases, particularly in the section where the polymer content is low near the raw material supply unit. Is also not preferred.
[0008]
As described above, it has been difficult in the prior art to produce a plate product with high plate thickness accuracy using a wide belt type continuous plate making apparatus with high productivity.
[0009]
[Patent Document 1]
Japanese Patent Publication No.51-27467
[0010]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described problems of the prior art. That is, an object of the present invention is to provide a belt-type continuous plate-making apparatus capable of producing a plate-like polymer having extremely high plate thickness accuracy regardless of the belt width of the apparatus, and a method for producing the plate-like polymer. .
[0011]
[Means for Solving the Problems]
As a result of repeating experiments to achieve the above object, the inventors of the present invention have sufficiently high rigidity of the roll body and a belt running direction if the outer diameter of the roll body of the pair of upper and lower rolls is within a certain range. It has been found that the distance between the roll pairs can be set to an appropriate distance so that the amount of bending of the belt is reduced, and a plate-like product with extremely high plate thickness accuracy in which the medium thickness shape is reduced can be obtained.
[0012]
That is, the present invention is sandwiched between the opposed belt surfaces of two endless belts arranged so that the opposed belt surfaces run in the same direction at the same speed, and the belt surfaces on both side portions thereof. In order to supply a polymerizable raw material from one end to a space surrounded by a continuous gasket running in a state, solidify the polymerizable raw material as the belt runs in the heating zone, and take out a plate-like polymer from the other end In the continuous plate making apparatus, the belt surface holding mechanism in the heating zone of the endless belt that travels relatively includes an upper roll that is in contact with the upper surface of the upper belt and a lower roll that is in contact with the lower surface of the lower belt. A plurality of upper and lower roll pairs perpendicular to the belt running direction are arranged along the belt running direction, and the roll body outer diameter D of the upper and lower roll pairs is 100 mm to 500 mm. When the total number of upper and lower roll pairs is 100%, the lower roll body of the upper and lower roll pairs having a number of 4% or more is crown-shaped. This is a belt type continuous plate making apparatus.
[0013]
Moreover, this invention is a manufacturing method of the plate-shaped polymer characterized by obtaining a plate-shaped polymer from the polymeric raw material containing methyl methacrylate using the said belt type continuous plate-making apparatus.
[0014]
The inventors of the present invention are further examining, among the pair of upper and lower rolls of the belt type continuous plate making apparatus, the upper roll is opposite in the direction of the repulsive force from its own weight and the liquid pressure in the raw material, the amount of deflection Since the lower roll has the same direction of the repulsive force from its own weight and the liquid pressure in the raw material, it has been found that the amount of deflection is much larger than that of the upper roll. In other words, it was found that correcting the deflection shape of the lower roll is the most effective way to eliminate the medium thickness shape of the product most effectively and to obtain a very smooth plate with no warpage. .
[0015]
Results of searching for a method for eliminating the medium-thickness shape of plate products based on this perspective ,under The lower roll barrel is adjusted to the belt surface by adjusting the line load from the upper roll barrel to the belt surface in advance. It was possible to easily control the shape to be transferred to the roller, and an innovative method was found that the medium thickness shape can be essentially eliminated without increasing the roll cylinder diameter and the roll pair interval.
[0016]
That is, according to the present invention, the lower roll shaft of the upper and lower roll pair is supported by the fixed side wall, the upper roll shaft of the upper and lower roll pair is supported by the vertically movable beam, and the spring is provided in contact with the beam. Using the belt type continuous plate making apparatus, the amount of deflection in the width direction of the upper roll and the lower roll is adjusted by adjusting the linear load applied to the belt surface by the upper roll by changing the compression length or stretching length of the spring. And a plate-like polymer obtained from a polymerizable raw material containing methyl methacrylate.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic cross-sectional view showing an example of a belt type continuous plate making apparatus of the present invention.
[0018]
In the apparatus shown in this figure, two endless belts (stainless steel belts, etc.) 1 and 1 ′ are tensioned by main pulleys 2, 3, 2 ′ and 3 ′, respectively, and a lower belt 1 by main pulley 3 ′. 'Start up and run. The liquid polymerizable raw material containing the polymerizable compound is fed by the metering pump 5 and supplied from the nozzle 6 onto the lower belt surface. The width of the endless belts 1 and 1 'is preferably 500 mm to 5000 mm, and the thickness is preferably 0.1 mm to 3 mm. The tension applied to the endless belts 1 and 1 'is a cross-sectional area of 1 mm perpendicular to the traveling direction. ² 1 kg to 15 kg is preferred. The endless belt 1 travels at the same speed in the same direction as the endless belt 1 ′ by a frictional force through a gasket or a plate-shaped polymer described later. The traveling speed is preferably 0.1 m / min to 10 m / min, and can be appropriately changed according to circumstances such as the thickness of the plate to be produced and the timing of product type switching.
[0019]
Both side portions between the belt surfaces are sealed with an elastic gasket 7. The polymerizable material solidifies the polymerizable material in the heating zone as the endless belts 1 and 1 ′ run. As a heating zone, the zone heated with the warm water sprays 8 and 8 'is mentioned, for example. Polymerization proceeds in the heating zone and reaches a temperature peak due to polymerization exotherm at a certain position. Thereafter, heat treatment is performed by, for example, far-infrared heaters 9 and 9 ′ to complete the polymerization, and a plate-like product (plate-like polymer) 10 is taken out. The section of the hot water sprays 8 and 8 ′ is preferably in the temperature range of 50 to 100 ° C., and the section of the far infrared heaters 9 and 9 ′ is preferably in the temperature range of 100 to 150 ° C. Moreover, you may use other heating systems, such as a hot air, in both areas. In addition, the upper and lower roll pairs of the present invention are intended for rolls in the heating zone and not for rolls in the section to be heat-treated.
[0020]
The belt surface holding mechanism in the heating zone of the endless belts 1, 1 ′ includes an upper roll in contact with the upper surface of the upper belt and a lower roll in contact with the lower surface of the lower belt, and each axis is orthogonal to the belt traveling direction. Upper and lower roll pairs 4, 4 'are used. And the effect of this invention is acquired by making roll trunk | drum outer diameter D of this upper and lower roll pair 4, 4 'into 100 mm-500 mm. If the outer diameter D is less than 100 mm, the amount of deflection of the roll body part may become so large that it exceeds the thickness of the plate-like product, and there is a risk that the upper and lower endless belt width direction end parts are in contact with each other. Arise. Further, when the outer diameter D exceeds 500 mm, it is necessary to increase the roll arrangement interval P in the belt running direction, and further, the roll self-weight increases, so that it is necessary to design the entire belt polymerization machine to have extremely high rigidity. Also, the equipment cost is not preferable. Furthermore, in the case of a large plate making apparatus having a belt width of 1800 mm or more, it is preferable that the outer diameter D of the roll body is 130 mm to 500 mm. Moreover, as for the dimensional accuracy of the roll trunk | drum in a flat roll, it is preferable that the tolerance of an outermost diameter is less than 0.1 mm.
[0021]
The difference PD between the arrangement interval P of the plurality of upper and lower roll pairs 4, 4 ′ in the belt running direction and the outer diameter D of the roll body should be as small as possible for the plate thickness accuracy. However, in the heating zone, if the difference PD is less than 50 mm, the contact area between the heating medium such as hot water spray and hot air and the belt surface may not be secured, resulting in a delay in the polymerization reaction and productivity. This is not preferable because it is significantly reduced. Further, if the difference PD exceeds 500 mm, it is not preferable because the endless belt bends between the roll pairs. Therefore, in the heating zone, it is preferable to design the difference PD between the roll arrangement interval P in the belt running direction and the roll body outer diameter D to be 50 mm to 500 mm. Moreover, all the roll pairs 4, 4 'may be arranged at equal intervals in the belt traveling direction, or may be arranged with partial intervals being changed.
[0022]
The polymerizable raw material is heated as the endless belts 1 and 1 ′ run, and the polymerization and solidification proceed. At a certain position, the temperature reaches a temperature peak due to the polymerization heat generation. The heating zone including the position showing the polymerization exothermic peak is usually provided with a plurality of upper and lower roll pairs 4, 4 '. In this section, a so-called crown roll having a roll body having a crown shape is used for at least a part of the plurality of lower rolls 4 ′. . This By introducing this crown roll, the medium thickness shape of the plate-like product derived from the deflection of the roll barrel can be substantially eliminated.
[0023]
Regarding the number of introduced crown rolls, when the total number of the upper and lower roll pairs 4 and 4 'disposed in the section is 100%, the lower roll 4' is a crown roll and the upper and lower roll pairs 4 and 4 ' The number should be 4% or more of the total number Is necessary 8% or more Prefer Preferably 10% or more Than preferable. The plurality of crown rolls may be continuously arranged in the belt traveling direction, or a flat roll (hereinafter simply abbreviated as “flat roll”) having a tolerance of the outermost diameter of the roll body within 0.1 mm. May be alternately or intermittently arranged every few.
[0024]
When producing a plate-like polymer using the belt-type continuous plate-making apparatus of the present invention, in the process of solidifying the polymerizable raw material while traveling with the belt, it is more than the position showing the polymerization exothermic peak in the heating zone. When the total number of upper and lower roll pairs disposed on the raw material supply side is 100%, the lower roll body portion of the upper and lower roll pairs having a number of 4% or more is preferably crown-shaped, and 8% or more. More preferably, it is more preferably 10% or more.
[0025]
When the travel speed of the endless belt varies depending on the production conditions and the position of the polymerization exothermic peak differs, the production supply condition is such that the position of the polymerization exothermic peak is closest to the raw material supply side. By introducing a crown roll as the lower roll 4 ′ of the upper and lower roll pairs, the effect can be exhibited for all production conditions.
[0026]
As for the introduction position of the crown roll, when the section from the entrance to the exit of the heating zone is 0% to 100%, the section between 0% and 90% is effective, and further within the section between 30% and 90%. It is more effective and preferable when concentrated.
[0027]
When producing a plate-like polymer using the belt type continuous plate making apparatus of the present invention, if the introduction position of the crown roll is upstream of the polymerization exothermic peak, solidification of the raw material by the polymerization reaction is still completed. Since it is not in a state, the shape of the roll body is effectively transferred to the shape of the raw material. In the process of solidifying the polymerizable raw material while traveling with the belt, when the section from the entrance of the heating zone to the position showing the polymerization exothermic peak is 0% to 100%, the lower roll body is crown-shaped. A certain pair of upper and lower rolls is preferably disposed in a section of 0% to 90%, and more preferably disposed in a section of 30% to 90%.
[0028]
FIG. 2 is a schematic cross-sectional view showing an example of a crown roll. In such a crown shape, the outermost diameter d of the end of the roll body shown by the following formula (1) ₁ And the outermost diameter d at the center ₂ It is preferable that the crown amount x expressed by a half of the difference in diameter with respect to the roll body self-weight deflection amount y calculated by the following equation (2) is in the relationship of the following equation (3).
[0029]
x = (d ₂ -D ₁ ) / 2 ... (1)
y = 5S × ρ × RW ^Four / (384 × E × I) (2)
x ≧ y (3)
S: Area of the cross section perpendicular to the axial direction of the roll body
ρ: Density of roll body material
RW: Roll body width
E: Young's modulus of roll body material
I: Second moment of the cross section perpendicular to the axial direction of the roll body.
[0030]
The crown shape may be either a radial type or a tapered type. In the present invention, the outer diameter D of the roll body is the outermost diameter d of the central portion in the case of a crown roll. ₂ It is.
[0031]
In the present invention, the distance in the belt traveling direction is represented by “length”, and the distance orthogonal to the belt traveling direction, that is, the distance in the roll axis direction is represented by “width”.
[0032]
Regarding the material of the body of the roll used for the upper and lower roll pairs 4, 4 ′, for example, a roll body made of various metals such as stainless steel, iron, and aluminum may be used, or a carbon-based composite such as a carbon roll. A roll body made of a material may be used. In addition, rubber may be coated on the surface of the roll body for the purpose of reducing damage to the stainless steel belt surface due to contact. Further, the outermost diameter after the rubber coating may be a crown shape. However, when the thickness of the rubber is increased, the roll cylinder diameter becomes too large, and the contact between the heating medium and the belt surface is hindered, and the amount of deflection of the roll cylinder is increased. Considering these points, the thickness of the coated rubber is preferably 3 mm to 20 mm.
[0033]
As the upper roll 4 of the upper and lower roll pairs 4, 4 ', either a flat roll or a crown roll can be used. However, when a crown roll is used, it is desirable that the crown amount x is smaller than that of the lower crown roll 4 ′ in consideration of warpage of the plate-like product.
[0034]
Next, a mechanism capable of changing the line load from the upper roll shaft portion of the upper and lower roll pairs 4, 4 'to the belt surface, and a method for controlling the plate thickness accuracy by load adjustment using this mechanism will be described in detail. .
[0035]
3A and 3B are schematic cross-sectional views illustrating a roll pair having a linear load adjusting mechanism using a flat roll as the upper roll 4 and a crown roll as the lower roll 4 ′. Both shaft portions of the lower roll 4 ′ are supported by a side wall 12 which is fixed to the base and does not move via a bearing. Both shaft portions of the upper roll 4 are supported via a bearing on a frame 11 that can be smoothly moved up and down by the vertical movement of the support bar 13.
[0036]
First, as shown in FIG. 3A, the natural length Z is provided on both sides of the frame 11. ₀ Spring 14 is Z ₀ Smaller value Z ₁ It is compressed between the frame 11 and the pedestal 15 so as to be (compression length). At this time, if the spring constant of the spring 14 is k, the force F that the spring 14 tries to push up the frame 11 ₁ Can be expressed by the following equation (4).
[0037]
F ₁ = K (Z ₀ -Z ₁ (4)
Here, the total weight of the upper roll 4 and the frame 11 is W _r When the belt width is BW, the load w per belt unit width transmitted from the upper roll 4 to the upper belt surface 1 ₁ Can be expressed by the following equation (5).
[0038]
w ₁ = (W _r -2F ₁ ) / BW (5)
In accordance with equation (4), the lower crown roll 4 ′ has a load w via the belt surface and the raw material. ₁ Is acting downward and this load w ₁ The roll body bends with the roll's own weight. However, by giving an appropriate crown shape to the lower crown roll 4 ′ in advance, the upper side of the roll body becomes a convex shape upward, and the cross-section of the liquid in the raw material becomes slightly thin in the width direction.
[0039]
Next, as shown in FIG. 3B, when the base 15 is moved downward and fixed, the spring length is Z ₁ Value Z greater than ₂ (Compression length) and force F ₁ Is the force F expressed by the following equation (6) ₂ It changes to.
[0040]
F ₂ = K (Z ₀ -Z ₂ (6)
As is clear from equations (4) and (6), F ₁ > F ₂ Therefore, the load w from equation (5) ₁ Is a larger load w ₂ The deformation of the lower roll 4 ′ is promoted, and the shape in the width direction of the raw material portion surrounded by the belts 1, 1 ′ and the gasket 7 becomes flat on both the upper and lower surfaces. That is, it is possible to obtain a width direction shape with extremely high flatness by adjusting the line load from above.
[0041]
Even if the spring incorporated in the load adjusting mechanism is a tension type, as shown in FIG. ₁ From the above, adjust the vertically movable beam 15 connected to the spring to make the extension length Z smaller than this ₂ (Z ₁ > Z ₂ ), The line load can be adjusted in exactly the same manner as when a compression spring is used.
[0042]
Load w per unit width transmitted from the upper roll 4 to the belt surface ₁ , W ₂ If it is too small, the adhesiveness between the gasket 7 and the upper and lower stainless steel belts 1, 1 ′ is lowered, and the risk of leakage of the raw material liquid to the outside is also not preferable. On the contrary, when the load is too large, it is necessary to extremely strengthen the shaft portion structure of the lower roll 4 ′, and the deformation of the side wall 12 cannot be ignored, and rather the plate thickness accuracy is lowered. . A preferable range of the load per unit width transmitted from the upper roll 4 to the belt surface is 10 kg / m to 200 kg / m.
[0043]
The mechanism for adjusting the load from the upper side of the present invention is not limited to the method of adjusting the force for supporting the frame supporting the shaft portion of the upper roll from below by the spring 14 as shown in FIG. For example, a system in which a force is directly applied to the connecting portion with the shaft portion of the upper roll may be used. Further, the direction of the force is not limited to the upward force as shown in FIG. 3, but may be a method in which the load is increased downward. One part for applying force may be provided for each pair of rolls, or a plurality of pairs of rolls may be connected by a frame, and a part for applying force to the frame via a spring may be provided.
[0044]
The thickness of the plate-like polymer (methacrylic resin plate) produced according to the present invention is preferably about 0.3 to 20 mm.
[0045]
The raw material of the plate polymer can be appropriately selected depending on the target plate polymer. The continuous plate making apparatus of the present invention is particularly suitable for the production of a methacrylic resin plate mainly composed of methyl methacrylate. When producing a methacrylic resin plate, it is preferable to use a polymerizable raw material containing 50% by mass or more of methyl methacrylate. Typically, methyl methacrylate alone or a mixture with other monomers copolymerizable with methyl methacrylate can be mentioned. Furthermore, syrup obtained by dissolving a methyl methacrylate polymer in methyl methacrylate or a mixture thereof, and syrup obtained by polymerizing a part of methyl methacrylate or a mixture thereof in advance are also included.
[0046]
Examples of other copolymerizable monomers include acrylic acid esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate; ethyl methacrylate, n-butyl methacrylate, methacryl Methacrylic acid esters other than methyl methacrylate such as 2-ethylhexyl acid; vinyl acetate, acrylonitrile, methacrylonitrile, styrene and the like. In the case of syrup, it is preferable to adjust the polymer content to 50% by mass or less in consideration of the fluidity of the polymerizable raw material.
[0047]
A chain transfer agent may be added to the polymerizable raw material as necessary. As the chain transfer agent, for example, a primary, secondary or tertiary mercaptan having an alkyl group or a substituted alkyl group can be used. Specific examples thereof include n-butyl mercaptan, i-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, s-butyl mercaptan, s-dodecyl mercaptan, t-butyl mercaptan and the like.
[0048]
Further, a polymerization initiator is usually added to the polymerizable raw material. Specific examples thereof include tert-hexyl peroxypivalate, tert-hexyl peroxy-2-ethylhexanoate, di-isopropyl peroxydicarbonate, tert-butyl neodecanoate, tert-butyl peroxy Organic peroxides such as pivalate, lauroyl peroxide, benzoyl peroxide, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxybenzoate, dicumyl peroxide, di-tert-butyl peroxide; 2,2'- Azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1-1′-azobis (1-cyclohexanecarbonitrile), 2,2′-azobis (2,4,4- Azo compounds such as trimethylpentane);
[0049]
In addition, various additives such as an ultraviolet absorber, a light stabilizer, an oxidation stabilizer, a plasticizer, a dye, a pigment, a release agent, an acrylic multilayer rubber, and the like can be added to the raw material as necessary.
[0050]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, these do not limit this invention.
[0051]
< Reference example 1 >
100 parts of methyl syrup methacrylate (viscosity 1 Pa · s, 20 ° C.) with a polymerization rate of 20%, tert-hexyl peroxypivalate (manufactured by NOF Corporation, trade name: perhexyl PV) 0.1 as a polymerization initiator As a mold release agent, 0.005 part of sodium dioctylsulfosuccinate was added and mixed uniformly to obtain a liquid polymerizable raw material. This polymerizable raw material was degassed in a vacuum vessel, and a plate-like product 1 having a thickness of 5 mm and a width of 1800 mm was produced using the apparatus shown in FIG.
[0052]
In the present embodiment, the apparatus of FIG. 1 has a total length of 10 m, the two stainless steel endless belts 1, 1 ′ have a thickness of 1.5 mm and a width of 2 m. ² Is given tension. Further, as the gasket 7, a gasket made of polyvinyl chloride is installed.
[0053]
The first half of the apparatus has a heating zone of 5 m for 76 ° C. hot water sprays 8 and 8 ′. In this heating zone, a total of 12 pairs of upper and lower roll pairs 4, 4 ′ are arranged at equal intervals so that the arrangement interval P of the roll pairs is 400 mm. Each of the upper and lower roll pairs 4, 4 'is composed of a stainless steel hollow body whose surface is covered with rubber and solid stainless steel shafts on both sides thereof. The outer diameter of the stainless body of each of the upper and lower roll pairs 4, 4 ′ is 160 mm, the outermost diameter including the rubber part is 180 mm, the width is 2200 mm, the stainless steel wall thickness is 4.5 mm, and the outermost diameter tolerance. Is a flat roll within 0.1 mm, the outer diameter of the solid shaft is 20 mm, and the width of the solid shaft is 125 mm.
[0054]
The self-weight deflection of this flat roll is 0.06 mm from the formula (2). Here, the difference PD between the arrangement interval P of the upper and lower roll pairs 4, 4 ′ in the heating zone and the roll body outer diameter D is 400 mm−180 mm = 220 mm.
[0055]
In the pair of upper and lower rolls 4 and 4 ′, the shaft of the upper roll 4 is supported via a bearing on a frame that can be moved up and down by the vertical movement of the support bar. Moreover, the axis | shaft of lower roll 4 'is supported through the bearing on the side wall 12 fixed to the base.
[0056]
Further, in the sixth and seventh upper and lower roll pairs 4 and 4 ′ from the raw material supply side in the heating zone, as shown in FIG. 3, the base 11 for supporting the shaft of the upper roll 4 and the support bar 13. A spring 14 is attached between the upper and lower rollers 15 to adjust the line load from the upper side. During operation, both the sixth and seventh upper and lower roll pairs 4, 4 ′ from the raw material supply side in the heating zone are on the upper side. The spring 14 was adjusted so that the load from the belt was 20 kg / m per belt unit width.
[0057]
After the heating zone by the hot water sprays 8 and 8 ', there is a section of 2 m for heat treatment by the far infrared heaters 9 and 9'.
[0058]
The driving speed of the endless belts 1 and 1 ′ was operated at 130 mm / min. Moreover, in order to grasp the polymerization exothermic peak, a thermocouple was introduced together with the raw material from the raw material supply side, and the temperature change of the liquid in the raw material in the vicinity of the thermocouple was measured to match the position of the polymerization apparatus. As a result, the polymerization exothermic peak was located 4.2 m from the raw material supply side of the heating zone by the hot water sprays 8 and 8 ′.
[0059]
<Example 2>
In the heating zone of the apparatus shown in FIG. 1, a crown roll is used instead of a flat roll as the second and third upper and lower roll pairs 4 and 4 'from the raw material supply side, that is, the raw material supply side. Except that the crown roll is used for the section of the warm water zone 12% to 28%, 17% of the total number of the lower rolls, Reference example 1 In the same manner, a plate-like product 2 was obtained. This crown roll has an outermost diameter d including rubber at the center. ₂ Is 180.0 mm (stainless steel barrel outer diameter 160.0 mm), outermost diameter d including rubber at the end ₁ Is 179.8 mm (stainless steel barrel outer diameter 160.0 mm), Reference example 1 The same structure and size as the flat roll used in The self-weight deflection of this crown roll is 0.06 mm from the formula (2).
[0060]
<Example 3>
In the heating zone of the apparatus of FIG. 1, the sixth and seventh upper and lower roll pairs 4, 4 ′ (with a linear load adjusting mechanism) from the raw material supply side are used as lower rolls 4 ′ instead of flat rolls. That is, except that the crown roll was used in the section of the hot water zone 44% to 60% as viewed from the raw material supply side, and 17% of the total number of the lower rolls, Reference example 1 In the same manner, a plate-like product 3 was obtained. This crown roll has the same structure and size as the crown roll used in Example 2.
[0061]
< Reference example 2 >
After degassing the polymerizable raw material 1 in a vacuum vessel, Reference example 1 A plate-like product 4 having a thickness of 3 mm and a width of 2800 mm was produced using the apparatus of FIG.
[0062]
In this embodiment, the apparatus of FIG. 1 has a total length of 100 m, the two stainless steel endless belts 1, 1 ′ have a thickness of 1.5 mm and a width of 3000 mm. ² Is given tension. Further, as the gasket 7, a gasket made of polyvinyl chloride is installed.
[0063]
The first half of the apparatus has a heating zone of 48 m for 80 ° C. hot water sprays 8 and 8 ′. In this heating zone, a total of 120 pairs of upper and lower roll pairs 4, 4 ′ are arranged at equal intervals so that the arrangement interval P of the roll pairs is 400 mm. Each of the upper and lower roll pairs 4 and 4 'includes a hollow body made of iron whose surface is covered with rubber, and solid stainless steel shafts on both sides thereof. And, the outer diameter of the iron barrel of each roll of the upper and lower roll pairs 4, 4 ′ is 264 mm, the outermost diameter including the rubber part is 280 mm, the width is 3200 mm, the iron part thickness is 7.6 mm, and the outermost diameter is The flat roll has a tolerance within 0.1 mm, the solid shaft has an outer diameter of 80 mm, and the solid shaft has a width of 400 mm.
[0064]
The self-weight deflection of this flat roll is 0.08 mm from the formula (2). Here, the difference PD between the arrangement interval P of the upper and lower roll pairs 4, 4 ′ and the roll body outer diameter D is 400 mm−280 mm = 120 mm.
[0065]
In the pair of upper and lower rolls 4, 4 ′, the shaft of the upper roll 4 is supported via a bearing on a frame that can be moved up and down by the vertical movement of the support bar. Moreover, the axis | shaft of lower roll 4 'is supported through the bearing on the side wall 12 fixed to the base.
[0066]
Further, in all the upper and lower roll pairs 4, 4 ′ in the heating zone, as shown in FIG. 3, a spring 14 is provided between the frame 11 that supports the shaft of the upper roll 4 and the base 15 of the support bar 13. Attach and adjust the line load from the upper side. During operation, the load from the upper side of the upper and lower roll pairs 4 and 4 'in the section of 20 to 28 m from the raw material supply side in the heating zone is 30 kg per belt unit width. The spring 14 was adjusted to be / m.
[0067]
After the heating zone by the hot water sprays 8 and 8 ′, there is a section for 15 m of heat treatment by the far infrared heaters 9 and 9 ′.
[0068]
In the heating zone with the hot water sprays 8 and 8 ', the temperature at the end in the width direction of the lower endless belt 1' is measured with a total of 12 thermocouples every 4 m, and the section showing the highest temperature is the position of the polymerization exothermic peak. It was said that. When the running speed of the endless belts 1 and 1 ′ was operated at 2.3 m / min, the polymerization exothermic peak was located in the section of 40 to 44 m.
[0069]
<Example 5>
The use of crown rolls instead of flat rolls as a total of 20 lower rolls 4 ′ in the section 20 to 28 m from the raw material supply side of the heating zone by the hot water sprays 8 and 8 ′ of the apparatus of FIG. Except for using the crown roll in the section of the warm water zone 42% to 58% as seen from the side, 17% of the total number of the lower rolls, Reference example 2 In the same manner, a plate-like product 5 was obtained. This crown roll has an outermost diameter d including rubber at the center. ₂ Is 280.0 mm (iron barrel outer diameter 264 mm), outermost diameter d including rubber at the end ₁ Is 269.6 mm (iron barrel outer diameter 264 mm), and the iron thickness is 7.6 mm, Reference example 2 The same structure and size as the flat roll used in The self-weight deflection of this crown roll is 0.08 mm according to the formula (2).
[0070]
In addition, the set value of the spring 14 attached to the frame 11 is changed with respect to the upper and lower roll pairs 4 and 4 ′ 20 to 28 m from the raw material supply side in the heating zone so that the load on the belt surface per belt unit width. Except having been set to 80 kg / m, 130 kg / m, and 180 kg / m, the plate-like product 6, the plate-like product 7, and the plate-like product 8 were obtained similarly to the case where the plate-like product 5 was obtained. .
[0071]
<Example 6>
The use of crown rolls instead of flat rolls as a total of 70 lower rolls 4 ′ in the section from 0 to 28 m from the raw material supply side of the heating zone by the hot water sprays 8 and 8 ′ of the apparatus of FIG. Except that the crown roll was used for the section of the warm water zone 0% to 58% as viewed from the side, 58% of the total number of the lower rolls, Reference example 2 In the same manner, a plate-like product 9 was obtained. This crown roll has the same structure and size as those used in Example 5.
[0072]
Further, the plate-like products 10 and 11 were obtained in the same manner as when the plate-like product 9 was obtained except that the running speed of the endless belt was changed to 1.8 m / min and 1.3 m / min. In addition, the polymerization heat_generation | fever peak position at this time was the area of 32-36m, 20-24m, respectively.
[0073]
<Comparative Example 1>
Except that the outer diameter of the stainless steel barrel is changed to 80 mm and the outermost diameter including the rubber part is changed to 96 mm in a total of 12 upper and lower roll pairs 4 and 4 ′ in the heating zone by the hot water sprays 8 and 8 ′. Reference example 1 In the same manner, a plate-like product 12 was obtained.
[0074]
< Reference example 3 >
The upper and lower roll pairs 4 and 4 'in the heating zone by the hot water sprays 8 and 8' are changed to a total of 6 pairs by thinning out every other pair, and the arrangement interval P of the lower roll pairs 4 and 4 'and the roll body are changed. Except that the difference PD with the part outer diameter D is 800 mm-180 mm = 620 mm. Reference example 1 In the same manner, a plate-like product 13 was obtained.
[0075]
< Reference example 4 >
Of the total of 20 lower rolls 4 ′ in the section 20 to 28 m from the raw material supply side of the heating zone by the hot water sprays 8 and 8 ′, four from the raw material supply side were changed to the crown rolls used in Example 5. That is, except that the crown roll is used for the section of the hot water zone 42% to 45% as viewed from the raw material supply side and 3.3% of the total number of the lower rolls. Reference example 2 In the same manner, a plate-like product 14 was obtained.
[0076]
<Evaluation>
Products 1-3 ( Reference Example 1, Examples 2, 3 ) And products 12, 13 (Comparative Examples 1 and 2) were evaluated by the following method. First, as shown in FIG. 5, the plate-like product taken out continuously was cut every 1000 mm to obtain 50 1800 mm × 1000 mm × 5 mm size plates. And about all 50 sheets, B in the 100 mm inner side from the cross-section width direction center A point and both ends. ₁ , B ₂ The thickness of the points was measured, the average value was calculated, and the intermediate thickness T represented by the following formula (7) was determined.
[0077]
T = A- (B ₁ + B ₂ ) / 2 (7)
In the plate thickness accuracy evaluation, the smaller the absolute value of the medium thickness T, the higher the flatness in the width direction.
[0078]
In addition, products 4-11 ( Reference Example 2, Examples 5 and 6 ) And product 14 (Comparative Example 3), as shown in FIG. 6, the size of 50 plates is 2800 mm × 1000 mm × 3 mm, and 200 mm inside from both ends is B ₁ , B ₂ The evaluation was performed in the same manner as described above except that the points were used.
[0079]
The evaluation results are shown in Table 1.
[0080]
[Table 1]

[0081]
As is apparent from the results shown in Table 1, the plate-like product 1 ( Reference example 1 ) Medium thickness shape T had a low value and sufficient flatness for light guide plate applications. Further, the medium thickness T of the plate-like product 2 (Example 2) has a lower value, and the medium thickness T of the plate-like product 3 (Example 3) has a lower value.
[0082]
Plate product 4 ( Reference example 2 In the same manner, the medium-thick shape T had a low value and was sufficiently flat for use as a light guide plate. Further, the medium thickness T of the plate-like products 5, 6, 7, and 8 (Example 5) are all low values, and the plate-like product 5 has particularly high flatness.
[0083]
The plate thickness products 9, 10 and 11 (Example 6) all had a low value for the medium thickness T. This shows that even if the continuous production speed during operation is changed, the high flatness of the plate-like product does not change.
[0084]
The medium thickness shape T of the plate-like product 12 (Comparative Example 1) was a high value and was a plate with poor plate thickness accuracy. Further, the plate-like product 13 ( Reference example 3 The value of medium thickness T is the plate product 1 ( Reference example 1 ) And the plate thickness accuracy was not excellent, but was superior to the plate of Comparative Example 1. Further, the plate-like product 14 ( Reference example 4 ) Medium thickness T is a plate-like product 4 ( Reference example 2 ) And the number of crown rolls introduced into the lower roll in the heating zone was 4% or less of the total number, so the effect was not significant.
[0085]
【The invention's effect】
As described above, according to the present invention, there are provided a belt-type continuous plate making apparatus capable of producing a plate-like polymer having extremely high plate thickness accuracy regardless of the belt width of the apparatus, and a method for producing the plate-like polymer. it can.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an example of a belt type continuous plate making apparatus of the present invention.
2 is a schematic view showing an example of a crown roll used for the lower roll 4 ′ of FIG. 1. FIG.
FIGS. 3A and 3B are schematic cross-sectional views illustrating a roll pair having a linear load adjusting mechanism using a flat roll as an upper roll and a crown roll as a lower roll. Two states in which the compression length is changed are shown.
FIGS. 4A and 4B are schematic cross-sectional views illustrating a roll pair having a linear load adjusting mechanism using a flat roll as an upper roll and a crown roll as a lower roll. Both figures are tension springs. Two states are shown in which the stretch length is changed.
FIG. 5 is a perspective view showing a plate size at the time of evaluation in Examples and Comparative Examples.
FIG. 6 is a perspective view showing a plate size at the time of evaluation in Examples and Comparative Examples.
[Explanation of symbols]
1, 1 'endless belt
2, 2 'main pulley
3, 3 'main pulley
4, 4 'Vertical roll pair
5 Metering pump
6 nozzles
7 Gasket
8 Hot water spray
9, 9 'far infrared heater
10 Plate products
11 frames
12 Side wall
13 Support rod
14 Spring
15 Pedestal or beam

Claims (13)

The two belts are arranged in such a way that the opposite belt surfaces run in the same direction at the same speed, and the two belts that are sandwiched between the opposite belt surfaces and the belt surfaces on both sides of the belts In a continuous plate making apparatus for supplying a polymerizable raw material from one end to a space surrounded by a gasket, solidifying the polymerizable raw material as the belt runs in a heating zone, and taking out a plate-like polymer from the other end The belt surface holding mechanism in the heating zone of the endless belt that travels relative to each other consists of an upper roll that contacts the upper surface of the upper belt and a lower roll that contacts the lower surface of the lower belt, and each axis is orthogonal to the belt traveling direction. upper and lower roll pairs are more disposed along a belt travel direction, the roll body outer diameter D of the upper and lower roll pairs is the 100Mm～500mm, the upper and lower rolls to total When defined as 100%, the belt type continuous steel plate and wherein the roll body portion of the lower side of the upper and lower roll pairs of more than 4% of the number is crown shape.   The belt-type continuous plate making apparatus according to claim 1, wherein the widths of the two endless belts are both 1800 mm or more and the outer diameter D of the roll body of the pair of upper and lower rolls is 130 mm to 500 mm.   The belt type continuous plate making apparatus according to claim 1 or 2, wherein a difference PD between an arrangement interval P and a roll body outer diameter D in the belt running direction of the plurality of upper and lower roll pairs is 50 mm to 500 mm. When the section from the entrance to the exit of the heating zone is 0% to 100%, the upper and lower roll pairs whose lower roll body is crown-shaped are arranged in the section of 0% to 90%. Item 2. The belt-type continuous plate making apparatus according to Item 1 . When the section from the entrance to the exit of the heating zone is 0% to 100%, the upper and lower roll pairs whose lower roll body is crown-shaped are disposed in the section of 30% to 90%. Item 2. The belt-type continuous plate making apparatus according to Item 1 . In the crown shape of the lower roll body, it is represented by half of the difference in diameter between the outermost diameter d ₁ at the end of the roll body and the outermost diameter d ₂ at the center shown by the following formula (1). The belt type continuous product according to any one of claims 1 to 5, wherein a crown amount x and a self-weight deflection amount y of the roll body calculated by the following formula (2) are in a relationship of the following formula (3). Board equipment.
x = (d ₂ −d ₁ ) / 2 (1)
y = 5S × ρ × RW ⁴ / (384 × E × I) (2)
x ≧ y (3)
S: Area of the cross section perpendicular to the axial direction of the roll body ρ: Density of the roll body material RW: Width of the roll body material E: Young's modulus of the roll body material I: Cross section perpendicular to the axial direction of the roll body Second moment The belt type continuous plate making apparatus according to any one of claims 1 to 6 , wherein all upper rolls of the upper and lower roll pairs are flat rolls having a tolerance of a roll body portion outermost diameter of 0.1 mm or less.   A plate-like polymer is obtained from a polymerizable raw material containing methyl methacrylate using the belt-type continuous plate-making apparatus according to claim 1. 9. The method for producing a plate-like polymer according to claim 8 , wherein the polymerizable raw material is disposed closer to the raw material supply side than a position showing a polymerization exothermic peak in the heating zone in the process of solidifying while the polymerizable raw material travels with the belt. When the total number of upper and lower roll pairs is 100%, a plate-like polymer manufacturing method using a belt-type continuous plate-making apparatus in which the lower roll body of the upper and lower roll pairs having a number of 4% or more has a crown shape . It is a manufacturing method of the plate-shaped polymer of Claim 9, Comprising: In the process which a polymeric raw material solidifies while drive | working with a belt, the area from the entrance of a heating zone to the position which shows a polymerization exothermic peak is 0%- When 100%, a pair of upper and lower rolls whose lower roll body is crown-shaped is a production of a plate-like polymer using a belt-type continuous plate making apparatus disposed in a section of 0% to 90%. Method. It is a manufacturing method of the plate-shaped polymer of Claim 9, Comprising: In the process which a polymeric raw material solidifies while drive | working with a belt, the area from the entrance of a heating zone to the position which shows a polymerization exothermic peak is 0%- When 100%, a pair of upper and lower rolls whose lower roll body is crown-shaped is a production of a plate-like polymer using a belt-type continuous plate making apparatus disposed in a section of 30% to 90%. Method. The belt according to claim 1, wherein a lower roll shaft of the upper and lower roll pairs is supported by a fixed side wall, an upper roll shaft of the upper and lower roll pairs is supported by a vertically movable beam, and a spring is provided in contact with the beam. Using a continuous plate making machine,
The amount of deflection in the width direction of the upper roll and the lower roll is adjusted by adjusting the linear load applied to the belt surface by the upper roll by changing the compression length or extension length of the spring, and the plate is formed from a polymerizable raw material containing methyl methacrylate. A method for producing a plate-like polymer, characterized in that a plate-like polymer is obtained. The method for producing a plate-like polymer according to claim 12 , wherein a linear load applied to the belt surface by the upper roll is adjusted to be within a range of 10 kg / m to 200 kg / m per belt unit width.

Images