JP2000037799A - Impact-resistant methacrylate resin plate excellent in molding appearance and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a methacrylate resin plate excellent in the balance of molding appearance and impact resistance. SOLUTION: In a resin plate comprising a methyl methacrylate resin containing 50 wt.% or more of a methyl methacrylate unit and a multilayered structural copolymer baing a rubbery copolymer layer wherein at least one layer has a crosslinked structure, at least one surface comprises a uniform dispersion layer in which the multilayered structural copolymer is uniformly dispersed and the other surface or interior comprises an aggregated layer wherein the multilayered structural copolymer is aggregated. This resin plate is produced by applying linear load to the polymerizable raw material held between a pair of endless belts in a fluidized state to complete polymn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a methyl methacrylate resin plate having an excellent balance between a molded appearance and impact resistance, and a method for producing the same.

[0002]

2. Description of the Related Art Methyl methacrylate resin plates are widely used for lighting equipment, signboards, various building materials, sound insulation boards, etc. due to their excellent transparency and surface gloss, good weather resistance and mechanical properties. However, the impact strength is not always sufficient, but rather it is fragile, and its improvement has been desired, and various proposals have been made so far.

For example, Japanese Patent Publication No. 55-27576 discloses a method for producing an impact-resistant composition comprising a methacrylic resin containing 4 to 90% by weight of a multistage successively produced polymer containing an elastomer layer by a casting method. ing. Also,
Japanese Patent Application Laid-Open No. 1-252653 discloses that a hard resin component is graft-polymerized to a rubbery copolymer having a crosslinked structure and an average particle diameter of 0.1 to 1 μm in 100 parts by weight of a methyl methacrylate resin. The obtained graft copolymer is
A cast plate dispersed in 30 parts by weight is disclosed. In JP-A-8-151498, 5 to 50 parts by weight of a methyl methacrylate polymer having a viscosity average molecular weight of 10,000 to 300,000 is dissolved in 100 parts by weight of a monomer containing methyl methacrylate as a main component, Furthermore, a method for producing a methyl methacrylate resin plate obtained by casting and polymerizing a syrup in which 1 to 50 parts by weight of a multilayer elastic body is dispersed is disclosed.

[0004]

However, although the methyl methacrylate resin plate obtained by the above method is excellent in impact resistance, there is a problem that the appearance of the molded plate is often deteriorated such as a mat-like surface of the resin plate. was there.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on the above problems, and as a result, controlling the dispersion state of the multilayer structure copolymer present in the methyl methacrylate resin plate has improved the impact resistance. The present inventors have found that a plate excellent in both appearances of the molded product can be obtained, and have reached the present invention.

That is, the gist of the present invention is to provide a resin plate comprising a methyl methacrylate resin containing at least 50% by weight of a methyl methacrylate unit and at least one layer of a multilayer copolymer having a rubbery copolymer layer having a crosslinked structure. The resin plate is characterized in that at least one surface is formed of a uniform dispersion layer in which the multilayer structure copolymer is uniformly dispersed, and the other surface or the inside is formed of an aggregation layer in which the multilayer structure copolymer is aggregated.

[0007] The gist of the present invention is to follow the running of the endless belt in a state where the pair of endless belts are opposed to each other and run at a predetermined interval, and are sandwiched between the pair of endless belts near both ends. A space consisting of two gaskets running in the form of a monomer comprising 50 to 100% by weight of a methyl methacrylate unit and 0 to 50% by weight of a monomer unit copolymerizable therewith from one end thereof; A monomer mixture or a mixture of a (co) polymer in which a part of the monomer is polymerized and a monomer, and a multilayer structure copolymer in which at least one layer is a rubber-like copolymer layer having a crosslinked structure Is continuously supplied to the belt surface from a direction perpendicular to the running direction of the belt and perpendicular to the belt surface while the raw material is in a fluidized state until the material is polymerized and solidified. To at least once 0.001
A method for producing a resin plate, characterized in that after applying a linear load of 0.0 kg / cm, polymerization is completed, and a plate-like polymer is taken out from the other end of the endless belt.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In a methyl methacrylate resin containing 50% by weight or more of methyl methacrylate units constituting a resin plate of the present invention, copolymerizable monomers used in combination with methyl methacrylate include ethyl methacrylate, Isopropyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, methacrylates such as benzyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic esters such as 2-ethylhexyl acrylate, acrylic acid, methacrylic acid, maleic acid, Unsaturated carboxylic acids such as itaconic acid, acid anhydrides such as maleic anhydride and itaconic anhydride, N-phenylmaleimide, N-cyclohexylmaleimide, Nt-butyl Maleimide derivatives such as maleimide, hydroxy group-containing monomers such as 2-hydroxypropyl acrylate, 2-hydroxyethyl acrylate and 2-hydroxypropyl methacrylate, (meth) acrylamide, (meth) acrylonitrile, diacetone acrylamide, dimethylaminoethyl methacrylate Such as nitrogen-containing monomers, epoxy group-containing monomers such as allyl glycidyl ether, glycidyl acrylate and glycidyl methacrylate, styrene monomers such as styrene and α-methylstyrene, ethylene glycol diacrylate, allyl acrylate, and ethylene glycol. Dimethacrylate, allyl methacrylate, divinylbenzene,
Crosslinking agents such as trimethylolpropane triacrylate and the like can be mentioned.

The composition and particle size of the multilayer copolymer constituting the resin plate of the present invention are not limited as long as at least one layer has a rubbery copolymer layer having a crosslinked structure. Examples of the rubbery copolymer having a crosslinked structure include diene polymers such as butadiene, isoprene and chloroprene, and acrylate polymers having an alkyl group having 4 to 10 carbon atoms such as butyl acrylate and 2-ethylhexyl acrylate. And a copolymer with a monomer copolymerizable therewith. As the copolymerizable monomer, styrene, styrene-based monomer such as α-methylstyrene, methyl methacrylate, methacrylic acid ester such as ethyl methacrylate, ethyl acrylate, carbon number of alkyl group such as butyl acrylate is 1 to 1. And vinyl cyanide compounds such as (meth) acrylonitrile, ethylene glycol di (meth) acrylate, allyl (meth) acrylate, divinylbenzene, and 1,3-butylene (meth) acrylate. Particularly, the alkyl group has 4 to 10 carbon atoms.
In the acrylic ester-based copolymer described above, at least one kind of the crosslinking agent component is contained as an essential component.

The multi-layer copolymer preferably has a polymer layer composed of a hard component on the outer layer of the rubbery copolymer layer, and the monomers constituting the hard component include methyl methacrylate and ethyl methacrylate. Examples include acrylates such as methacrylate, methyl acrylate, and ethyl acrylate; nitrogen-containing monomers such as (meth) acrylonitrile; and styrene-based monomers such as styrene and α-methylstyrene. These monomers alone,
Or two or more are used.

In the present invention, the state of dispersion of the multilayer structure copolymer in the resin plate is represented by the degree of aggregation defined by the following equation (1).

Cohesion degree = [{(average number of multilayer structure copolymers occupying each portion Nm Nm−number of multilayer structure copolymers occupying each portion N) ² ｝ ^1/2 ] / 3 (1) Cohesion degree Is an index indicating the state of aggregation of the multilayer structure copolymer dispersed and present in the resin plate, and indicates the degree of aggregation of the multilayer structure copolymer in an arbitrary portion of the resin plate. In the formula (1), a large degree of aggregation means that the degree of aggregation of the multilayer structure copolymer is large, and a small degree of aggregation means that the multilayer structure copolymer is more uniformly dispersed. means. In the present invention, the term “homogeneous dispersion layer” in which the multilayer copolymer is uniformly dispersed (hereinafter, referred to as “homogeneous dispersion layer”) means a layer having a cohesion degree of less than 8, and an aggregate layer in which the multilayer copolymer is aggregated. (Hereinafter, referred to as “aggregated layer”) means a layer having a degree of aggregation of 8 or more. The cohesion degree defined by the formula (1) in each uniform dispersion layer or coagulation layer is as follows:
It is determined at an intermediate point in the thickness direction of each layer.

The degree of agglomeration is determined by first taking a photograph of the multilayer structure copolymer contained in the resin plate at a magnification of, for example, about 4000 times, and setting the average rubber particle diameter of the multilayer structure copolymer to R. In the photo, randomly select 10 square frames each having a size of about 10 ⁵ × R in the photograph. Next, after calculating the number N of the multilayer structure copolymer in each square, it is calculated according to the formula (1). Here, the average value Nm of the number of multilayer structure copolymers occupying each part is the average value of the number of polymers observed in the above-mentioned 10 randomly selected squares.

If the uniform dispersion layer has a cohesion degree of 8 or more, the surface of the resin plate at the time of molding is reduced in gloss and the surface becomes mat-like, which is not preferable from the viewpoint of molding appearance. It is preferably 6 or less, more preferably 5 or less.

The uniform dispersion layer needs to be present on at least one surface of the resin plate, and one uniform dispersion layer preferably has a thickness of 1 to 40% of the total thickness of the resin plate. If the uniform dispersion layer is too thin, the appearance of the molded product becomes poor, which is not preferable. Therefore, the lower limit of the ratio of one uniform dispersion layer is 5
% Or more, more preferably 10% or more.
On the other hand, if the uniform dispersion layer is too thick, the impact resistance decreases, which is not preferable. Therefore, the upper limit of the ratio of one uniform dispersion layer is more preferably 35% or less, and further preferably 30% or less.

When the uniformly dispersed layer is present on only one surface of the resin plate, the other surface is an agglomerated layer, and when the uniformly dispersed layer is present on both surfaces, the inside is an agglomerated layer.

If the cohesion of the coagulation layer is less than 8, the impact resistance is undesirably reduced. It is preferably 10 or more, and more preferably 20 or more. On the other hand, if the agglomeration degree is too high, the transparency of the resin plate decreases, so the agglomeration degree is preferably 100 or less.

When the uniform dispersion layer is present only on one surface, the above-mentioned aggregated layer preferably has a thickness of 60 to 99% of the total thickness of the resin plate. If the cohesive layer is too thin, the impact resistance is not sufficiently exhibited, which is not preferable. The lower limit of the ratio of the aggregated layer is more preferably 65% or more, and further preferably 70% or more. On the other hand, if the cohesive layer is too thick, it is not preferable because the appearance of the resin plate becomes poor or other physical properties such as transparency are reduced. The upper limit of the ratio of the aggregated layer is more preferably 95% or less, and further preferably 90% or less.

When a uniform dispersion layer is present on both surfaces, the cohesive layer preferably has a thickness of 20 to 98% of the total thickness of the resin plate. The lower limit is more preferably at least 30%, even more preferably at least 40%. The upper limit is more preferably 90% or less, and further preferably 80% or less.

In the present invention, in order to obtain a methyl methacrylate-based resin plate having a uniform dispersion layer on at least one surface and an aggregated layer on the other surface or inside, a resin plate or film corresponding to the uniform dispersion layer must be prepared in advance. And a method of manufacturing a resin plate or film corresponding to the cohesive layer, and then bonding them together, or a polymerizable material containing a multilayer structure copolymer, by sealing the periphery with a gasket and facing two metal plates facing each other. After pouring into a cell, a linear load is applied while moving a rubber roll or the like back and forth in a water bath to polymerize.

Particularly preferable methods from the viewpoint of productivity and the like include:
Opposing surfaces of a pair of endless belts that run oppositely at a predetermined interval, and two gaskets that run following the running of the endless belt while being sandwiched between the pair of endless belts near both end portions thereof; And a methyl methacrylate unit 5
0 to 100% by weight and a monomer unit 0 copolymerizable therewith
50% by weight of a monomer or monomer mixture or a mixture of a monomer and a (co) polymer in which a part of the monomer is polymerized, and a rubbery copolymer having at least one layer having a crosslinked structure A polymerizable raw material comprising a mixture with a multilayer structure copolymer which is a united layer is continuously supplied, and while the raw material is in a fluidized state until it is polymerized and solidified, it is perpendicular to the running direction of the belt and perpendicular to the belt surface. A method in which a linear load of 0.001 to 10.0 kg / cm is applied to the belt surface at least once from the direction to uniformly disperse the multilayer copolymer on the surface of the resin plate.

As the polymerization apparatus used in this method, which comprises a pair of endless belts running opposite to each other at a predetermined interval, for example, a known apparatus described in JP-B-46-41602 can be used. One specific example is shown in FIG.
Shown in

In FIG. 1, a pair of endless belts 1 and 2 arranged vertically are main pulleys 3, 4, 5, and 6, respectively.
, And are driven to run at the same speed. The upper and lower carrier rolls 7 support the traveling endless belt horizontally, and at least once from the direction perpendicular to the traveling direction of the belt and perpendicular to the belt surface at a rate of 0.001 to 10.0 kg / cm. Apply a linear load. The linear load is more preferably 0.01 kg / cm or more.
In addition, when the number of times of applying the line load increases, the dispersion of the uniform dispersion layer on the surface of the obtained resin plate becomes more uniform.

The polymerizable raw material is supplied between a pair of endless belts by a raw material injection device 14. Two elastic gaskets 12 are provided near both ends of the pair of endless belts.
Sealed with.

The polymerizable raw material is heated by the hot water spray 9 in the first polymerization zone 8 and polymerized as the endless belt runs, and then heated by the far-infrared heater in the second polymerization zone 10 to complete the polymerization. Zone 11
, And is taken out as a plate-like polymer 13.

The mixture of the monomer and the (co) polymer obtained by partially polymerizing the monomer in the above-mentioned polymerizable raw material comprises methyl methacrylate or methyl methacrylate and a monomer copolymerizable therewith. It is preferable that the monomer or a part of the monomer mixture is polymerized and has a polymerization rate of 35% by weight or less.

Further, a chain transfer agent can be added to the polymerizable raw material. The chain transfer agent may be selected from those usually used in radical polymerization, and is preferably a mercaptan-based chain transfer agent such as an alkyl mercaptan having 2 to 20 carbon atoms, mercapto acid, thiophenol or a mixture thereof. It is. Still more preferably, it is a mercaptan having a short alkyl chain such as n-octyl mercaptan or n-dodecyl mercaptan.

In order to polymerize this polymerizable raw material, it is preferable to use a radical polymerization initiator such as an azo compound or an organic peroxide. As the azo compound, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,
4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile) and the like. On the other hand, as the organic peroxide, benzoyl peroxide, lauroyl peroxide and the like can be mentioned. Is mentioned. Further, a redox-based polymerization initiator, for example, a combination of an organic peroxide and an amine can also be used.

The polymerization temperature for producing the resin plate of the present invention by the casting polymerization method varies depending on the type of radical polymerization initiator used, but is generally from 10 to 150 ° C.

The thickness of the cast plate obtained by the casting polymerization method is not particularly limited, but is preferably a commercially available thickness, that is, in the range of 1 to 120 mm.

Further, in the method of the present invention, a colorant and an ultraviolet ray may be used in any convenient step from the step of mixing a monomer or the step of polymerizing a part of the monomer to the step of continuously supplying a polymerizable raw material. Absorbers, heat stabilizers, other antistatic agents, fillers and the like can be added.

[0032]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In each example, “parts” means parts by weight unless otherwise specified.

In the examples, each abbreviation indicates the following compound.

MMA: methyl methacrylate MA: methyl acrylate BA: n-butyl acrylate St: styrene AMA: allyl methacrylate BDMA: 1,3-butylene glycol dimethacrylate n-OM: n-octyl mercaptan n-DM: n-dodecyl mercaptan CHP: cumene hydroperoxide t-BH: t-butyl hydroperoxide AIBN: azobisisobutyronitrile PHPV: t-hexylperoxybivalate EAP: ethyl acid phosphate TV-P: 2- (5-methyl- 2-hydroxyphenyl) benzotriazole sanol LS-2626: 1- {2- [3- (3,5-
Di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl {-4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy]-
2,2,6,6-tetramethylpiperidine sanol LS-770: bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate AOT: dioctyl sodium sulfosuccinate AO-50: octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate EDTA · 2Na: disodium ethylenediaminetetraacetate dihydrate SFS: sodium formaldehyde sulfoxylate Emulsifier (X): mono (polyoxyethylene nonylphenyl) Partially neutralized product of a mixture of 40% of ether) phosphoric acid and 60% of di (polyoxyethylene nonylphenyl ether) phosphoric acid in sodium hydroxide The physical properties in Examples and Comparative Examples were evaluated by the following methods.

1) Measurement of agglomeration degree When the length direction of the resin plate is the X direction, the width direction is the Y direction, and the thickness direction is the Z direction, the X direction is 0.1 m in the X direction.
The size is about 0.1 mm in the m and Z directions and the thickness is 70 nm.
A thin section was cut out using a microtome over the entire thickness direction of the resin plate. The flakes were dyed by leaving them in the gas phase of a sample bottle containing a 0.5% by weight ruthenium tetroxide aqueous solution at room temperature for 2 hours. The stained slice was photographed under a transmission electron microscope (TEM) at a magnification of 4200 times. 2.4 × 2.4 for each photo
10 frames are randomly selected from the photograph as an arbitrary part, the number N of the multilayer structure copolymer in each frame is counted, the degree of agglomeration is calculated according to the equation (1), and the uniform dispersion layer is calculated. The approximate thickness of the aggregation layer was calculated. From the calculated approximate thickness, select a photograph of a slice containing both the uniform dispersion layer and the aggregation layer, divide the Z direction on the photograph into equal parts, and determine the degree of aggregation of each divided area by the same method. The thickness of the uniformly dispersed layer and the aggregated layer was determined. Regarding the thickness of each layer of the uniform dispersion layer and the cohesion layer determined in this way, the cohesion degree at the middle point in the thickness direction of each layer is calculated by the same method, and these values are calculated. Degree.

2) Hydroshot high-speed surface impact strength A resin plate was cut out to a size of 100 × 100 mm, and a shot core diameter: 1/2 inch, a punching speed: 2 m / sec, and a measurement temperature of 23 ° C. were measured using a hydroshot manufactured by Shimadzu Corporation. The surface impact strength was measured under the conditions.

3) Surface gloss A resin plate having a thickness of 3 mm or 6 mm is 170 × 170 mm.
Cut into corners, vacuum forming machine (Model FK-0) manufactured by Asano Lab.
431-1-10), the resin plate having a thickness of 3 mm is biaxially stretched to 1 mm at a temperature of 160 ° C. and the resin plate having a thickness of 6 mm is stretched at 2 mm to obtain a digital gloss meter (20 °, 60 °).
°) Using a GM-26D type [manufactured by Murakami Color Research Laboratory Co., Ltd.], the gloss of the resin plate surface in the stretched portion was measured.

4) Measurement of Surface Roughness After the resin plate was biaxially stretched in the same manner as in 3) Surface gloss, the surface of the stretched portion was subjected to surf test 20 manufactured by Mitutoyo Corporation.
1 was measured. Measure the unevenness of the surface of the stretched resin plate surface in a section of 5 mm in any direction in the arbitrary direction, and select five places from the obtained chart as the concave parts in the section in the order of the lowest peak, and as the convex parts, start from the highest peak. I chose 5 places. The difference between the average value of the height at five places and the average value of the height at five places was expressed in μm. In the chart, 0.3μ
LESS PEAK was described for the case where three or more peaks of m or more were not measured in the measurement section.

[Embodiment 1] This embodiment is an example in which a line load is applied only to the upper cell.

To a reaction vessel equipped with a reflux condenser, 300 parts of ion-exchanged water was added, the temperature was raised to 80 ° C., 4 × 10 ⁻⁵ parts of iron (II) sulfate heptahydrate, 1.2 × 10 ⁵ of EDTA · 2Na
^-4 parts and 0.4 parts of SFS were added and maintained for 10 minutes. Thereafter, 40 parts of the monomer mixture (a-1) having the composition shown in Table 1 (hereinafter, the monomer mixture given a reference number is the same as described in Table 1), and a polymerization initiator. t-BH0.
1/10 of a mixture of 07 parts and 1.2 parts of emulsifier (X) was added and the mixture was kept for 15 minutes. Thereafter, the remaining mixture of the monomer mixture, the polymerization initiator, and the emulsifier was continuously added at a rate of 20 parts / hour, and then kept for 1 hour to perform polymerization of the innermost layer to obtain a latex.

Then, in the presence of this latex, SFS
0.2 part was added and the mixture was held for 15 minutes, and the monomer mixture (b-
1) A mixture of 60 parts, a polymerization initiator CHP 0.17 part, and an emulsifier (X) 1.8 parts was continuously added at a rate of 20 parts / hour, and then maintained for 2 hours to polymerize the intermediate layer. went.

Next, in the presence of this latex, SFS
0.2 part was added and the mixture was held for 15 minutes, and the monomer mixture (c-
1) A mixture of 60 parts and 0.1 part of a polymerization initiator t-BH,
It was added continuously at a rate of 30 parts / hour, and then kept for 2 hours to polymerize the outermost layer, thereby obtaining a latex of a multilayer copolymer.

Next, this latex was coagulated with an aqueous solution of calcium acetate, washed, dehydrated and dried to obtain a multilayer copolymer (hereinafter referred to as polymer A).

12.8 parts of polymer A, 100 parts of a mixture of a polymer of methyl methacrylate and a monomer (viscosity: 100 centipoise, conversion: 10% by weight) were mixed. Further, 0.008 part of polymerization initiator AIBN was added to this mixture, and PHP was added.
0.35 parts of V, 0.005 parts of mold release agent AOT (trade name, manufactured by American Cyanamid Co.), 0.01 parts of EAP,
0.06 part of chain transfer agent n-DM, ultraviolet absorber TV-
0.3 parts of P (trade name, manufactured by Ciba Geigy) and 0.5 parts of light stabilizer SANOL LS2626 (trade name, manufactured by Sankyo Co., Ltd.)
To obtain a polymerizable raw material. The raw material was reduced in pressure to remove dissolved air, and then poured into a cell formed of a gasket and two 1.5 mm-thick mirror-finished 50 × 50 cm square stainless steel plates formed at intervals of 4.2 mm. . This cell was immersed in warm water of 76 ° C. and polymerized for 40 minutes. At this time, a diameter of 8 cm and a length of 2 cm
By applying a 7 cm rubber roll, a linear load of 1 kg / cm was applied from the vertical direction of the cell surface. During the polymerization for 40 minutes, the roll was reciprocated 9 cm at a time in both directions in which the roll rotated from the center of the cell in parallel with the sides of the cell. The moving speed of the roll was 4 cm / sec. Then, polymerization was carried out in a heating furnace at 125 ° C. for 60 minutes to obtain a plate thickness of 3 mm.
Was obtained.

A portion where a linear load was applied was cut out from the obtained resin plate, and the portion was evaluated. The results shown in Table 2 were obtained.

[Embodiment 2] This embodiment is an example in which a line load is applied only to the upper cell.

A mixture of 12.8 parts of the polymer A described in Example 1, a polymer of methyl methacrylate and a monomer (having a viscosity of 1
(100 centipoise, polymerization rate: 10% by weight). Further, the polymerization initiator AIBN was added to the mixture at 0.0
08 parts, PHPV 0.32 parts, mold release agent AOT 0.0
05 parts, EAP 0.01 parts, chain transfer agent n-DM 0.06 parts, ultraviolet absorber TV-P 0.3 parts, light stabilizer SANOL LS770 (trade name, manufactured by Sankyo Co., Ltd.) 0.
3 parts and 0.2 part of Stabilizer Mark AO-50 (trade name, manufactured by Asahi Denka Kogyo KK) were added to obtain a polymerizable raw material. The raw material was reduced in pressure to remove dissolved air, and then poured into a cell formed of a gasket and two 1.5 mm-thick mirror-finished 50 × 50 cm square stainless steel plates formed at an interval of 7.7 mm. . This cell was immersed in warm water of 72 ° C. and polymerized for 60 minutes. At that time, a rubber roll having a diameter of 9 cm and a length of 27 cm was applied to the upper surface cell from the outside to apply a linear load of 2.5 kg / cm from the vertical direction of the cell surface. During this 60-minute polymerization, the roll was repeatedly rotated in both directions from the center of the cell parallel to the sides of the cell.
The roll was reciprocated by cm. The moving speed of the roll was 4 cm / sec. Then, in a heating furnace at 125 ° C., 60
Polymerization was performed for 1 minute to obtain a methacrylate resin plate having a plate thickness of 6 mm.

A portion where a linear load was applied was cut out from the obtained resin plate, and the portion was evaluated. The results shown in Table 2 were obtained.

[Embodiment 3] This embodiment is an example in which a line load is applied to both the upper cell and the lower cell.

A polymerizable raw material similar to that of Example 1 was prepared, and after removing dissolved air under reduced pressure, a mirror-finished stainless steel endless belt having a thickness of 1.5 mm and a width of 3000 mm was prepared as shown in FIG. The feed was injected into the indicated continuous polymerization apparatus. In this continuous polymerization apparatus, the belt interval was adjusted to 4.2 mm at the raw material injection section. At right angles to the running direction of the endless belt with carrier rolls that are paired up and down,
Polymerization was carried out while applying a linear load of 1 kg / cm from the vertical direction to the belt surface and applying 78 ° C. warm water from the back surface of the belt under the condition that the residence time was 35 minutes in the first polymerization zone. In the second polymerization zone, the residence time was 5 minutes, and the polymerization was completed under the condition that the belt back surface temperature was 120 ° C. by the far infrared heater. Thus, a methacrylate resin plate having a thickness of 3 mm was obtained. The resin plate was evaluated, and the results shown in Table 2 were obtained.

Comparative Example 1 A methacrylate resin plate having a thickness of 3 mm was obtained in the same manner as in Example 1 except that polymerization was performed without applying a linear load to the cells. Was obtained. The cohesion of the resin plate was substantially uniform in all the thickness directions of the plate.

Comparative Example 2 A methacrylate resin plate having a thickness of 6 mm was obtained in the same manner as in Example 2 except that polymerization was performed without applying a linear load to the cell. Was obtained. The cohesion of the resin plate was substantially uniform in all the thickness directions of the plate.

Comparative Example 3 A methyl methacrylate resin plate having a thickness of 3 mm was obtained in the same manner as in Example 3, except that a polymerizable raw material was prepared without adding a multilayer structure copolymer. It was evaluated and the results in Table 2 were obtained. The resin plate did not contain the multilayer structure copolymer, and the cohesion was uniform in all the thickness directions.

Comparative Example 4 12.8 parts of polymer A and MFR
= 2 after mixing with 100 parts of a general purpose methacrylic resin.
Using a twin screw extruder with a mm vent, melt-knead into pellets and extrude with a T-die extruder to obtain a plate thickness of 3 mm
To obtain a methacrylate resin plate, and evaluate the resin plate,
The results in Table 2 were obtained. The cohesion of the resin plate was substantially uniform in all the thickness directions of the plate.

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

The resin plate of the present invention has good molded appearance after molding and is excellent in impact resistance. The range of use of this resin board in various fields such as signboards, various panels, covers, building materials, sound insulation boards, etc. is expanded. Further, a resin plate can be obtained with high productivity by the production method of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic view of a continuous polymerization apparatus in Example 3 of the present invention.

[Description of Signs] 1, 2 ... Endless belt 3, 4, 5, 6 ... Main pulley 7 ... Carrier roll 8 ... First polymerization zone 9 ... Hot water spray 10 ... Second polymerization zone 11 ... Cooling zone 12 ... Gasket 13 ... Plate-like polymer 14: Raw material injection device

Continued on the front page F term (reference) 4F100 AK25A AL05A AN02A AN02J BA01 EJ05A EJ05J GB07 GB90 JK10 JK15 4F204 AA21K AA45 AG02 AH46 AH51 AH81 AR02 EA03 EB02 EK04 EK10

Claims (2)

[Claims] 1. The method according to claim 1, wherein the methyl methacrylate unit is 50% by weight.
In a resin plate comprising a methyl methacrylate-based resin and a multilayer copolymer having at least one layer of a rubbery copolymer layer having a crosslinked structure, at least one surface has a uniform dispersion in which the multilayer copolymer is uniformly dispersed. A resin plate comprising a layer, and the other surface or inside of the resin plate is formed of an aggregated layer in which a multilayer copolymer is aggregated. 2. The vehicle runs following the running of the endless belt while being sandwiched between the pair of endless belts near the opposite end portions thereof at the opposing surfaces of the pair of endless belts running opposite to each other at a predetermined interval. A monomer or monomer mixture consisting of 50 to 100% by weight of a methyl methacrylate unit and 0 to 50% by weight of a monomer unit copolymerizable with the methyl methacrylate unit from one end of a space formed by the two gaskets. Or some of those monomers polymerized (co)
A polymerizable raw material comprising a mixture of a mixture of a polymer and a monomer and at least one of a multilayer structure copolymer which is a rubbery copolymer layer having a crosslinked structure is continuously supplied, and the raw material is polymerized. While in the fluidized state until solidification, at least once from the direction perpendicular to the running direction of the belt and from the direction perpendicular to the belt surface to the belt surface at least 0.001 to 10.0 kg / cm.
The method according to claim 1, wherein after the linear load is applied, the polymerization is completed, and the plate-like polymer is taken out from the other end of the endless belt.