JPH05331298A - Production of delustered thermoplastic resin sheet - Google Patents

Abstract

PURPOSE:To obtain a delustered thermoplastic resin sheet by dispersing delustering polymer particles and/or inorganic fine particles in a thermoplastic resin followed by putting the mixture through rolls and by cooling it under specified conditions with its surface being out of contact with the rolls brought to a specified temperature to effect intense and homogeneous incorporation of the particles in the mixture. CONSTITUTION:Delustering polymer particles (e.g. cross-linked methacrylic resin particles) and/or inorganic fine particles (e.g. glass beads) are dispersed in a thermoplastic resin (e.g. methacrylic resin), and the resulting mixture is put through two or more rolls to produce a resin sheet. In this case, just after releasing off the final roll, the temperature Tr of the surface of the resin sheet being out of contact with this roll is brought to a temperature between Th and (Th+70 deg.C) (where, Th is the heat distortion temperature of the thermoplastic resin) followed by cooling the temperature of the sheet from Tr to Th in such a time as to be expressed as the number of seconds equal to the numerical value at least ten times that corresponding to the thickness of this resin sheet in terms of mm, thus obtaining the objective delustered thermoplastic resin sheet with the delustering fine particles more intensely and homogeneously incorporated even with the same amount thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a matte thermoplastic resin sheet. More specifically, it relates to a method for producing a matte resin sheet based on a method for producing a resin sheet via a roll.

[0002]

2. Description of the Related Art Molded products manufactured from thermoplastic resins often have gloss. However, there are applications where it is preferred to remove gloss. Examples thereof include a surface plate of a transmissive display, a lighting cover, interior / exterior parts for automobiles, and exterior parts for household electric appliances. Conventionally, as a method of reducing the gloss of a synthetic resin molded article, there are a method of subjecting a molding die surface such as a mold to unevenness, and a method of applying a matting agent to the surface of the molded article.

Further, there is a resin in which inorganic fine particles and polymer particles which are not melted at the processing temperature of the resin are mixed to form unevenness on the surface of the resin. For example, as disclosed in JP-A-53-147748, JP-A-58-29622 and JP-A-58-141232, talc, barium sulfate, white carbon and calcium carbonate are mixed in an acrylic resin and melted. An extruded resin plate after kneading is disclosed. Further, JP-A 1-287161 discloses a composition in which an acrylic high molecular weight or cross-linked polymer is mixed in an acrylic resin and a method of obtaining a matte molded article by injection molding the composition. ing.

[0004]

A method for producing a plate-like composition by using a plurality of rolls, such as extrusion molding, of a composition in which inorganic fine particles and unmelted polymer particles are mixed in a resin has a mirror surface. The finished roll surface is transferred, and it is difficult for matte to develop sufficiently. This is also described in JP-A-1-287161. Further, if a large amount of the particles are mixed to develop matte, the impact strength of the resin plate is lowered.

However, the resin sheet is manufactured by using a plurality of rolls like the extrusion molding method and the calendering method.
Since it is a very general method and is excellent in mass productivity, the present invention provides a method for producing a sufficient matt even in a method for producing a sheet by using these plural rolls.

[0006]

Means for Solving the Problems In the present invention, when a matting polymer particle and / or an inorganic fine particle is dispersed in a thermoplastic resin and a resin sheet is produced by using this dispersed particle through two or more rolls, Immediately after peeling from the final roll, the surface temperature Tr of the resin sheet on the side not in contact with the roll is set to the heat deformation temperature Th of the thermoplastic resin or more to Th + 70 ° C., and then the Tr is cooled to Th. In addition, the present invention provides a method for producing a matte thermoplastic resin sheet, which is characterized in that a time which is 10 times or more the numerical value of the thickness of the resin sheet expressed in mm is set as the number of seconds.

Examples of the thermoplastic resin in the present invention include acrylic resin, polycarbonate resin, styrene resin, vinyl chloride resin, polyethylene resin, polypropylene resin, polyester resin, polyacetal resin, fluorine resin, nylon resin, and the like. It can be processed into a shape and has a glass transition temperature Tg of room temperature or higher.

The acrylic resin referred to here is a methyl methacrylate homopolymer or a methyl methacrylate as a main component, and a (meth) acrylic acid ester or (meth) acrylic acid, styrene or acrylonitrile. , Those obtained by copolymerizing α-methylstyrene, maleic anhydride, glutaric anhydride, glutarimide, diene rubber, or those reinforced with an elastomer such as acrylic rubber or butadiene rubber are applicable. In addition,
Examples of the (meth) acrylic acid ester include methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and cyclohexyl methacrylate.

Similarly, in other resins, not only a homopolymer but also various copolymers are collectively referred to.

The matting polymer particles are those which do not melt at the molding and processing temperature of the thermoplastic resin. Although these are well known, specifically, a polymer having a cross-linked structure, or a polymer having a high degree of polymerization, fine powder obtained by crushing these polymers, or emulsion polymerization, suspension polymerization method, The fine particles produced by the micro suspension polymerization method or the like are applicable.

Among the crosslinked polymers, there are so-called thermosetting resins, polymers of polyfunctional monomers having two or more ethylenically unsaturated groups in one molecule, or ethylenically unsaturated groups in one molecule. And other polymers of polyfunctional monomers having a polycondensation functional group, and further, a copolymerization of a monofunctional monomer having one ethylenically unsaturated group in one molecule and the polyfunctional monomer. There is coalescence.

Examples of polyfunctional monomers having two or more ethylenically unsaturated groups in one molecule include polyhydric alcohols such as ethylene glycol dimethacrylate, polyethylene glycol diacrylate, trimethylolpropane trimethacrylate, and pentaerythritol tetramethacrylate. (Meth) acrylic esters of; allyl (meth)
Allyl esters such as acrylate, diallyl phthalate and diallyl adipate, divinyl ethers; divinylbenzene and the like, but not limited to these.

Polyfunctional monomers having a polyfunctional group having an ethylenically unsaturated group and other polycondensation functional groups in one molecule include allyl glycidyl ether and glycidyl (meth) acrylate. It is not limited.

Specific examples of the monofunctional monomer having one ethylenically unsaturated group per molecule include alkyl methacrylate such as methyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate. Esters; acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid; acrylonitrile, methacrylonitrile, Aromatic vinyl monomers such as styrene and α-methylstyrene; vinyl acetate, vinyl chloride, vinylidene chloride and the like.

As the matte inorganic particles, well-known particles such as calcium carbonate, barium sulfate, silica, aluminum hydroxide, talc, mica, titanium oxide, glass beads, calcium silicate and the like are applicable.

When selecting these matting particles, by matching the refractive index with the thermoplastic resin, it is possible to manufacture a matting sheet having excellent transparency.

The particle size of the matting polymer particles and / or the inorganic particles used in the present invention is not particularly limited, but may be 0.
It is about 1 to 1000 μm. The smaller the particle size, the smaller the matting effect itself, but a finer matte is exhibited. The larger the particle size, the coarser the matte texture. If it is too large, the matting effect will rather decrease. Therefore, the particle size may be selected according to the use of the resin sheet.

The amount of the particles to be blended is appropriately selected depending on the application, but in the present invention, even if used in an equivalent amount, the matting effect is more exerted than in the conventional method. For example, in the case of a resin sheet to which particles having a refractive index very similar to that of a thermoplastic resin are added, and in the case where the importance is attached to the transparency, 0.1 to 5% by weight,
When it is mainly used for the purpose of preventing reflection of light, it is about 5 to 30% by weight.

The method for dispersing the particles in the thermoplastic resin may be a known method. That is, it is a method of mechanically mixing both with a Henschel mixer, a tumbler, etc., and melt-kneading with a Banbury mixer or a single-screw or twin-screw extruder. Alternatively, in the case of a vinyl chloride resin, as described in JP-A-54-134793, a vinyl chloride monomer containing a polyfunctional monomer is polymerized, and a vinyl chloride resin having crosslinked particles dispersed therein is used. There is also a method of obtaining a resin.

During the above mixing, if necessary, an antioxidant, a weatherproofing agent, a lubricant, a plasticizer, a dye / pigment, a filler and the like can be added.

A method for producing a resin plate through two or more rolls is a typical method for producing a resin plate / sheet, for example, "Handbook of Plastic Processing Technology" (October 20, 1979). Pp.254-260: "Plastic sheet extrusion technology" (19)
May 29, 1969 (published by the Industrial Research Board): "Plastics" vol.33, No. 10 (October 1982 issue, published by the Industrial Research Board) 49-56, "Appearance Improved plastic sheet molding technology ”: Japanese Patent Publication Sho 61-4
"Extruder", "Die", "Rolled roll unit (polishing roll machine)", "Roller table", "Ear trimming device", "Take-off roll", "Cutting," There is a so-called extrusion molding method using a device having a structure of a "stacking device". In addition, as described on pages 323 to 360 of the above "Handbook of Plastic Processing Technology", there is a so-called calendar processing method using a device of "kneading device" for resin and "calender roll".

In any case, in order to make the surface of the resin sheet smooth, the roll group in contact with the resin in a molten state is usually a glossy roll. In the present invention, the temperature Tr of the surface of the resin sheet immediately after peeling from the final roll of the roll group, which is not in contact with the final roll, exceeds the heat distortion temperature Th of the resin and is within the range of Th + 70 ° C., preferably Is within the range of Th + 15 ° C to Th + 50 ° C. The heat distortion temperature Th is a value measured according to ASTM D-648.

The adjustment of Tr is performed by adjusting the temperature of the extruded or rolled resin before being applied to the glossy roll, adjusting the temperature of the glossy roll, and adjusting the residence time of the glossy roll. This is done by one of a method of externally heating the resin sheet which is in contact with the glossy roll or a combination thereof, which is well known to those skilled in the art as described in JP-B-61-46305. Can be done very easily.

When Tr is less than Th, the matte expression is not sufficient and it is unevenly expressed. If the Tr is too high, the sheet cannot be normally and smoothly peeled off from the roll, and it takes a long time to cool.

The present invention has found that after the sheet is peeled from the final roll, matte is mainly developed, and that the thickness of the sheet and the cooling rate are involved.
Specifically, in order to reduce Tr to Th, the cooling time is set to the number of seconds which is 10 times or more the numerical value representing the thickness of the sheet in mm. If the cooling time is shorter than this condition, the matte appearance is not sufficient.

The cooling time of the sheet may be adjusted by a known cooling method while observing the transition of the temperature of Tr. For example, the roller table through which the sheet passes after the final roll,
Use a structure that allows temperature control through the heat medium, and change the temperature of this heat medium to adjust the temperature of the roller table to control the cooling rate of the sheet; or the atmosphere through which the sheet from which the final roll has been peeled passes. The temperature of the sheet is adjusted to control the cooling rate of the sheet; there is a method of externally heating the sheet after peeling the final roll. You may combine these adjustment methods.

After passing through the above cooling conditions, a sheet is obtained through known steps thereafter.

[0028]

According to the present invention, in a method for producing a matte resin sheet by an extrusion molding method, a calender molding method or the like, it is stronger even if the mixing amount of the matting fine particles is the same,
A uniform matte sheet can be obtained.

[0029]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The evaluation method is as follows. -Glossiness: Measure the matte resin sheet surface not in contact with the final roll with a glossmeter (UGV-4D made by Suga Test Instruments) at 60 ° reflection in accordance with the glossiness measurement of JIS Z-8741. did.・ Total light transmittance and haze; Poic integrating sphere type haze meter (SEP-HS-3 manufactured by Nippon Seimitsu Optical Co., Ltd. according to ASTM -1003
0D). -Surface roughness: Ten-point average roughness was measured by a surface roughness profile measuring device (Surfcom 550A manufactured by Tokyo Seimitsu Co., Ltd.) according to JIS-B0601. Resin sheet surface temperature: The resin surface temperature was measured with a contact thermometer (TD-150 manufactured by Shibaura Electronics Co., Ltd.).・ Surface appearance judgment: The light from a fluorescent lamp is reflected indoors on the matte resin sheet of the sample to visually observe the uniformity of matte, and a uniform one is ○, a little uneven △, and a lot of unevenness It was represented by x.

The apparatus used is as follows.・ Extruder: Screw diameter 40 mm, uniaxial, manufactured by Tanabe Plastic Co., Ltd. ・ T die: width 220 mm, lip gap 4 mm ・ Polishing roll: diameter 200 mm, width 300 mm, 3 pieces ・ Roller table: diameter 50 mm, width 350 mm, 3 pieces Installed at intervals of 30cm, 50cm, 80cm from the roll

Example 1 Methacrylic resin (Sumihex B EX heat distortion temperature Th 97 ° C.)
Sumitomo Chemical Co., Ltd. 100 parts by weight with hollow glass beads (Micro Balloon S40, manufactured by Fuji Devison Chemical Co., Ltd.)
Particle size distribution 8-150μm, average particle size 38μm) 0.5
After adding by weight and mixing with a Henschel mixer, the molten resin sheet was extruded with an extruder at a resin temperature of 265 ° C. at the die exit. The temperature of the polishing roll is set to the upper roll 110.
C., middle roll 118.degree. C., lower roll 120.degree. C., the molten resin sheet is passed along the middle roll through the gap between the upper roll and the middle roll, and is passed along the lower roll through the gap between the middle roll and the lower roll. Immediately after the peeling, the Tr of the sheet was set to 110 ° C., then the sheet was passed over a roller table set to 80 ° C., and the Tr was cooled to 97 ° C. of Th over 24 seconds after peeling from the lower roll. A sheet having a thickness of 2 mm was obtained. The evaluation results of the obtained sheet are shown in Table 1.

Example 2 The same procedure as in Example 1 was repeated except that the amount of hollow glass beads added was 2 parts by weight. The evaluation results of the obtained sheet are shown in Table 1.

Comparative Examples 1 and 2 In Examples 1 and 2, the temperature of the polishing roll was set to 95 ° C. for the upper roll, 108 ° C. for the middle roll and 110 ° C. for the lower roll, and the Tr of the sheet immediately after the peeling was Th or less. Of 93
It carried out similarly except having set it as (degreeC). The evaluation results of the obtained sheet are shown in Table 1.

Example 3 In place of the hollow glass beads in Example 1, crosslinked methacrylic resin beads (Sumi-Pex B XC-01 manufactured by Sumitomo Chemical Co., Ltd., particle size distribution 8 to 80 μm, average particle size 40 μm)
A molten resin sheet was extruded in the same manner except that 1 part by weight of was added. The temperature of the polishing roll is set to the upper roll 115.
C., the middle roll 123.degree. C., and the lower roll 110.degree.
Then, the roll non-contact surface of the sheet along the lower roll is heated by a pipe heater to set the Tr of the sheet immediately after peeling the lower roll to 102 ° C., and the surface of the sheet passing on the roller table is also piped. After being heated with a heater and peeled from the lower roll, Tr was cooled to Th over 14 seconds to obtain a sheet having a thickness of 1 mm. The evaluation results of the obtained sheet are shown in Table 1.

Example 4 The same procedure as in Example 3 was carried out except that 10 parts by weight of the crosslinked methacrylic resin beads were added and a molten resin sheet was extruded, and that the Tr of the sheet immediately after the lower roll was peeled was 103 ° C. A sheet having a thickness of 1 mm was obtained. The evaluation results of the obtained sheet are shown in Table 1.

Comparative Examples 3 and 4 The same procedure as in Examples 3 and 4 was carried out except that the heating of the pipe heater was not performed and the peeled sheet had a Tr of 90 ° C. or lower. Table 1 shows the evaluation results of the obtained sheets.
Shown in.

Example 5 The temperature of the polishing roll in Example 3 was set to 95 ° C. for the upper roll, 108 ° C. for the middle roll and 110 ° C. for the lower roll, and the Tr of the sheet immediately after peeling was 107.
The same procedure was performed except that the temperature was set to 0 ° C., Tr was cooled to Th over 25 seconds after peeling from the lower roll, and the sheet thickness was set to 2 mm. Table 1 shows the evaluation results of the obtained sheets.
Shown in.

Example 6 The temperature of the polishing roll in Example 4 was set to 95 ° C. for the upper roll, 108 ° C. for the middle roll and 110 ° C. for the lower roll, and the Tr of the sheet immediately after peeling off the lower roll was 104.
The same procedure was performed except that the temperature was set to 0 ° C., the Tr was cooled to Th over 27 seconds after peeling from the lower roll, and the sheet thickness was set to 2 mm. Table 1 shows the evaluation results of the obtained sheets.
Shown in.

Comparative Example 5 Without heating the pipe heater in Example 5,
Immediately after peeling the sheet from the lower roll to 98 ° C. immediately after peeling the lower roll, cooling was performed to Th for 5 seconds after peeling from the lower roll. The evaluation results of the obtained sheet are shown in Table 1.

Comparative Example 6 The heating of the pipe heater in Example 6 was not performed at all,
Immediately after the lower roll was peeled, the Tr was 97 ° C. The evaluation results of the obtained sheet are shown in Table 1.

Example 7 The temperature of the polishing roll in Example 3 was set to 90 ° C. for the upper roll, 103 ° C. for the intermediate roll and 105 ° C. for the lower roll, and the Tr of the sheet immediately after peeling off was 106.
The same procedure was performed except that the temperature was set to 0 ° C, Tr was cooled to Th over 40 seconds after peeling from the lower roll, and the sheet thickness was 3.5 mm. The evaluation results of the obtained sheet are shown in Table 1.

Example 8 The temperature of the polishing roll in Example 4 was set to 90 ° C. for the upper roll, 103 ° C. for the intermediate roll and 105 ° C. for the lower roll, and the Tr of the sheet immediately after peeling off was 108.
The same procedure was performed except that the temperature was set to 0 ° C, Tr was cooled to Th over 44 seconds after peeling from the lower roll, and the sheet thickness was 3.5 mm. The evaluation results of the obtained sheet are shown in Table 1.

Comparative Example 7 Without heating the pipe heater in Example 7,
Immediately after removing the lower roll, the Tr of the sheet was set to 103 ° C., and the Tr was cooled to Th for 23 seconds after peeling from the lower roll. The evaluation results of the obtained sheet are shown in Table 1.

Comparative Example 8 Without heating the pipe heater in Example 8,
Immediately after the lower roll was peeled off, the sheet had a Tr of 104 ° C., and the peeling from the lower roll was performed for 23 seconds, and then the Tr was cooled to Th. The evaluation results of the obtained sheet are shown in Table 1.

[0045]

[Table 1]

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Claims (1)

[Claims] 1. Dispersing polymer particles for matting and / or inorganic fine particles in a thermoplastic resin, and producing a resin sheet through two or more rolls, immediately after peeling from the final roll, The surface temperature Tr of the resin sheet on the side not in contact with the roll is set to not less than the thermal deformation temperature Th of the thermoplastic resin to Th + 70 ° C., and subsequently, the thickness of the resin sheet is set to cool the Tr to Th. A method for producing a matte thermoplastic resin sheet, which comprises applying a time which is 10 times or more the value expressed in mm and which is the number of seconds.