JPH0948841A - Copolyester sheet and three-dimensional molded form made thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject sheet of high three-dimensional processability which is, with high productivity, capable of providing three-dimensional molded forms excellent in resistance to moist-heat distortion, transparency, impact resistance, chemical resistance, heat stability, gas barrier property, UV-screening action, heat sealability, recyclability, etc. SOLUTION: This sheet is composed of (1) telephthalic acid as dicarboxylic acid component, and ethylene glycol as diol components, with both the components being the main components, and as copolymer components, (2) 5-25mol% of naphthalene dicarboxylic acid, based on the total of the dicarboxylic acid components, and (3) 0.1-5mol% of diethylene glycol based on the total of the diol components, having (4) intrinsic viscosity of 0.5-1.5dl/g, (5) glass transition temperature (Tg) of 75-95 deg.C, (6) crystallization temperature (Tc) of 160-195 deg.C determined under temperature rise, (7) thickness of 0.1-15 mm, (8) haze of 0-6%, and (9) haze/mm of 0-6%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to wet heat deformation resistance, transparency, impact resistance, chemical resistance, thermal stability, gas barrier property,
The present invention relates to a transparent sheet made of a copolyester excellent in three-dimensional processability, which can provide a three-dimensional molded product excellent in ultraviolet blocking property, heat seal property, recyclability and the like with high productivity.

[0002]

2. Description of the Related Art Polyethylene terephthalate (hereinafter,
It is called "PET". ) Is excellent in mechanical strength, chemical stability, transparency, hygiene and the like, and is lightweight and inexpensive, so that it is widely used as various sheets and containers for packaging materials. In particular, in recent years, from the viewpoint of waste disposal problems and environmental protection, the development of applications such as extruded sheets and squeezed containers, which have been frequently used for polyvinyl chloride and polystyrene, has been remarkable.

For example, in the case of a squeezed container, such a PET is generally manufactured by extruding a sheet with an extruder and then squeezing. However, a transparent squeezing container obtained by squeezing a conventional PET sheet is used in an unstretched state or a low stretched state without being subjected to a crystallization treatment, and therefore it does not necessarily have sufficient wet heat resistance. It is hard to say, especially if it is kept under high temperature and high humidity conditions such as during transportation, side and corner parts will shrink, and deformation such as warpage and swelling will occur on flat parts such as side and bottom. There is a problem that it easily occurs.

On the other hand, as a processing method for improving the heat resistance of the drawn product, the sheet is uniaxially stretched, then heated to a predetermined temperature to shrink it, and then heat-processed (Japanese Patent Laid-Open No. 50-21051). Japanese Patent Laid-Open No. 57-53316), after biaxially stretching the sheet, performing heating in an inert gas and deep drawing, and then rapidly cooling it to a temperature below the second-order transition temperature (Japanese Patent Laid-Open No. 57-53316). A method of axially stretching and heat-treating with a mold having a temperature 70 ° C. lower than the crystallization temperature and lower than the crystallization temperature, and then cooling with a cooling mold (Japanese Patent Publication No. 1-285050, US Pat. No. 4,388,356), sheet Biaxially stretched to 1
180 to 2 after the shrinkage ratio at 50 ° C. is 3% or less
A method of pressure forming at 40 ° C. (Japanese Patent Laid-Open No. 58-67411) and the like have been proposed. However, since a sheet stretching operation is required, the processing cost is higher than that of the conventional processing method, and the production is further improved. There is a problem that it deteriorates. Moreover, after heating the sheet to a temperature lower than the low temperature crystallization temperature to make the hanging length of the sheet 5 to 50% of the diameter of the die opening, the sheet is molded by a die at 70 ° C. or lower (Japanese Patent Publication No. 6-49334). Issue) is also proposed. Although this method has higher productivity than the method requiring the above-mentioned stretching operation, since the sheet is heated to the low temperature crystallization temperature or higher, the PET forming the sheet is easily crystallized, and continuous thermoforming for a long time is performed. Then, there is a problem that the generation rate of the molded body lacking transparency becomes higher than that in the conventional method.

Further, the above-mentioned processing method for improving the heat resistance of the draw-formed product may not be applicable depending on the target shape, size and thickness of the draw-formed product. It is required to improve the heat resistance of the polyester, that is, the heat resistance of the polyester itself. On the other hand, heat-resistant resins such as polycarbonate resins and polyarylate resins are known as resins having excellent resistance to moisture and heat deformation,
Attempts have been made to use these by blending or laminating them with PET, but coloring occurs during molding, the haze value of the resulting molded article becomes high, and the productivity decreases as compared with conventional methods. There is such a problem. Furthermore, because these heat-resistant resins have significantly different structures from PET,
There is a problem in recycling as PET.

By the way, in the three-dimensional processing of a thick sheet (board) having a thickness of more than 2 mm, it becomes difficult to quickly heat the surface and the inside of the sheet without unevenness, and the surface temperature of the sheet is indispensable. It will be higher than that. Therefore, the conventional PET board has a problem that the crystallization proceeds at a high temperature portion of the sheet surface because the crystallization speed is too fast, resulting in low transparency (high haze value). Therefore, conventionally, as a raw material for these boards, an acrylic resin or a polycarbonate resin which is an amorphous and highly transparent resin has been used. However, the acrylic resin has a problem of low impact resistance. Further, although polycarbonate has high resistance to moist heat deformation and impact resistance, it has low chemical resistance and poor moldability, and there is a problem that it is necessary to dry the sheet for three-dimensional processing, for example.

On the other hand, as the polyester board, an amorphous copolymerized PET obtained by copolymerizing PET with a large amount of cyclohexanedimethanol, for example, a transparent board made of Kodar PETG6763 manufactured by Eastman Chemical Company is known. However, there is a problem that the wet heat deformation resistance of the PET board is not substantially improved and the chemical resistance is lowered. Furthermore, a copolymerized PE in which a large amount of cyclohexanedimethanol was copolymerized
Since T is amorphous, it is necessary to dry at the time of forming a sheet at a temperature lower than that of ordinary PET, and since it is more easily thermally decomposed than PET, it causes troubles in color tone deterioration. There is a problem that it is easy.

On the other hand, many copolyesters having properties similar to PET, for example, copolyesters using terephthalic acid and naphthalenedicarboxylic acid as the dicarboxylic acid component and ethylene glycol and diethylene glycol as the diol component are known. . However, as compared with the conventional PET sheet, the three-dimensional processing made of a specific copolyester that can provide a three-dimensional molded product having improved three-dimensional processing property and improved wet heat deformation resistance and transparency. No clear sheet suitable for use was specifically known.

[0009]

DISCLOSURE OF THE INVENTION An object of the present invention is to improve wet heat deformation resistance and transparency, as well as impact resistance and chemical resistance, as compared with a conventional three-dimensional molded article using a PET sheet. It is possible to provide a transparent three-dimensional molded product having excellent heat resistance, heat stability, gas barrier property, ultraviolet ray blocking property, heat sealing property, recyclability, and the like, and also a highly transparent and thick three-dimensional molded product. Conventional PE that can
It is intended to provide a copolyester sheet having improved three-dimensional processability as compared with a T-made sheet, and a three-dimensional molded body obtained by three-dimensionally processing the copolyester sheet.

[0010]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found a specific copolyester sheet and arrived at the present invention. That is, the gist of the present invention is (1) terephthalic acid as a dicarboxylic acid component, ethylene glycol as a main component as a diol component, and (2) naphthalene dicarboxylic acid as a copolymerization component in an amount of 5 to 25 moles based on all dicarboxylic acid components. %,
(3) Diethylene glycol is contained in an amount of 0.1 to 5 mol% based on all diol components, and (4) the intrinsic viscosity is 0.5 to
1.5 dl / g, (5) glass transition temperature (Tg) is 75
~ 95 ° C, (6) Temperature rising crystallization temperature (Tc) is 160 ~ 1
95 ° C., (7) Thickness is 0.1 to 15 mm, (8) Haze value is 0 to 6%, (9) Haze value per mm of thickness is 0.
The present invention relates to a copolyester sheet and a three-dimensional molded body composed of the copolyester sheet.

The present invention will be described in detail below. The copolyester constituting the sheet of the present invention is a copolyester having terephthalic acid and ethylene glycol as main components, and as a copolymerization component, naphthalene dicarboxylic acid is contained in an amount of 5 to 25 mol% as a ratio to all dicarboxylic acids. Preferably 6-20 mol%, more preferably 7-1
7 mol%, particularly preferably in the range of 8 to 15 mol%, and diethylene glycol is 0.1 to 5 mol% as a ratio to the total diol component, preferably 0.1.
It is contained in an amount of 5 to 4 mol%, more preferably 1 to 3.5 mol%.

When the naphthalene dicarboxylic acid copolymerization amount of the copolyester constituting the sheet is less than 5 mol%, the three-dimensional molded body is resistant to the heat and moisture deformation as compared with the case where the conventional PET sheet is used. Substantially no improvement in properties is observed, and a sufficient whitening-suppressing effect is not observed when a three-dimensional molded body having a large thickness is manufactured by three-dimensional processing. When the amount of naphthalene dicarboxylic acid copolymerization exceeds 25 mol%, the impact resistance of the transparent three-dimensional molded article may be significantly reduced, and the compatibility with PET may be reduced to deteriorate the material recyclability. It is not preferable because it exists.
On the other hand, when the diethylene glycol copolymerization amount exceeds 5 mol%, the degree of improvement in the wet heat deformation resistance of the three-dimensional molded body is small and the thermal decomposition during the melt molding of the sheet becomes remarkable, which is not preferable.

Regarding naphthalenedicarboxylic acid which is a copolymerization component of the copolyester constituting the sheet of the present invention, 2,6-, 2,7-, 1,4-, 1,5-, 1,
Examples of naphthalene dicarboxylic acid such as 8-, and 2,3-, but any naphthalene dicarboxylic acid may be used, and further, these naphthalene dicarboxylic acids may be used alone, You may use it in combination of 2 or more type. Of these naphthalenedicarboxylic acids, 2,6- and 2,7- are preferred.
Naphthalene dicarboxylic acid, more preferably 2,
6-naphthalenedicarboxylic acid.

Further, in the copolyester constituting the sheet of the present invention, a small amount of components other than terephthalic acid, naphthalenedicarboxylic acid, ethylene glycol and diethylene glycol are copolymerized within a range not departing from the constitutional requirements of the present invention. Good. Of these copolymerization components,
As for the difunctional component, as the dicarboxylic acid component, an aromatic dicarboxylic acid such as phthalic acid, isophthalic acid, 4,4′-diphenylsulfone dicarboxylic acid or 4,4′-biphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid Alicyclic dicarboxylic acids such as, aliphatic dicarboxylic acids having an aromatic ring such as 1,3-phenylenedioxydiacetic acid, succinic acid, adipic acid, sebacic acid, and aliphatic dicarboxylic acids such as diglycolic acid. be able to. Examples of the oxycarboxylic acid component include p-hydroxybenzoic acid, 4- (2-hydroxyethoxy) benzoic acid, glycolic acid and the like. further,
As the diol component, 1,2-propanediol, 1,
3-propanediol, 1,4-butanediol, 1,
6-hexanediol, neopentyl glycol, 2-
Aliphatic diols such as butyl-2-ethyl-1,3-propanediol, alicyclic glycols such as 1,4-cyclohexanedimethanol, p-xylylene glycol, 2,2-bis (4- (2- Examples thereof include alkylenediols having an aromatic ring such as hydroxyethoxy) phenyl) propane and 4,4′-bis (2-hydroxyethoxy) diphenylsulfone. In these bifunctional copolymerization components, the ratio of constitutional repeating units containing these components to all constitutional repeating units is usually 10 mol% or less,
The amount is preferably such that the total carboxylic acid component and the total hydroxy component of the copolyester are substantially equal in the range of 5 mol% or less.

Further, a small amount of trifunctional or higher polyfunctional components may be copolymerized within a range not departing from the constitutional requirements of the present invention. As the trifunctional or higher polyfunctional component, a known compound generally used in PET may be used, but for example, a polyvalent carboxyl component such as trimellitic acid, trimesic acid, and pyromellitic acid, trimethylolethane. Examples thereof include polyhydric hydroxy components such as trimethylolpropane, glycerin and pentaerythritol, and glycidyl ether components of aromatic dihydroxy compounds such as bisphenol A diglycidyl ether and bisphenol S diglycidyl ether. These trifunctional or higher polyfunctional components are not particularly required to be used, but when they are used, they are contained in a range in which gelation does not substantially progress, that is, in all monomer unit components constituting the copolyester. On the other hand, usually 1.0 mol% or less,
It is preferably in the range of 0.6 mol% or less. Since a small amount of the polyfunctional component is copolymerized, the degree of drawdown of the sheet when the sheet is three-dimensionally processed tends to be smaller.

Further, a small amount of monofunctional component may be copolymerized within a range not departing from the constitutional requirements of the present invention. Examples of the monofunctional component include benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, stearic acid, benzyl alcohol and stearyl alcohol. When using these monofunctional components, it is usually 0.005 to all components constituting the copolyester.
It is desirable that the amount is 1.0 mol%, preferably 0.01 to 0.75 mol%. Since the monofunctional component is copolymerized, the thermal stability at the time of forming the sheet is improved, and the acetaldehyde content of the transparent sheet of the present invention can be suppressed to be smaller.

As described above, the copolymerization composition of the copolyester constituting the sheet of the present invention is substantially the same as the copolyester composition of the raw material of the copolyester used for forming the sheet. Incidentally, the sheet of the present invention, within the range not departing from the constitutional requirements of the present invention, hindered phenol-based or phosphorus-based, antioxidants such as thioether-based, coloring agents such as titanium dioxide, nucleating agents such as talc, carbonic acid. Lubricants such as calcium and silica, as well as additives such as release agents, flame retardants, heat stabilizers, hydrolysis resistant agents, antistatic agents, hard coating agents, UV absorbers, light resistant stabilizers, optical brighteners, etc. It may be appropriately contained. These additives may be added as they are during the production of the sheet, or may be added in the form of a masterbatch, or may be added during the production of the raw material copolyester. Furthermore, these additives may be used for the surface treatment of the sheet by a method such as coating or lamination.

The intrinsic viscosity of the copolyester constituting the sheet of the present invention is 30 in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio = 1/1).
0.5-1.5 dl / g, preferably 0.55-1.3 dl / g, more preferably 0.6 when measured at ° C.
~ 1.1 dl / g, particularly preferably 0.65-1.0d
1 / g. If the intrinsic viscosity is less than 0.5 dl / g, it may not have sufficient practical strength, and
Particularly, drawing or blow processing is not preferable because the thickness unevenness of the obtained molded article becomes large. Also, 1.5 dl /
If it exceeds g, the moldability during three-dimensional processing is poor, and when the sheet is melt-formed, the melt viscosity is too high, resulting in large shear heat generation in the molding machine, resulting in thermal decomposition. Is remarkable, which is not preferable.

The sheet of the present invention has a glass transition temperature (hereinafter referred to as "Tg") measured by a differential scanning calorimeter (hereinafter referred to as "DSC") of 75 to 95 ° C, preferably 77. To 93 ° C., particularly preferably 78 to 92 ° C., and the temperature rising crystallization temperature (hereinafter referred to as “Tc”) is 160 to 195 ° C., preferably 165 to 19 ° C.
It is 0 ° C., more preferably 170 to 185 ° C. When the Tg is less than 75 ° C., it is not preferable because the three-dimensional molded body is not substantially improved in the resistance to moist heat deformation as compared with the case where the conventional PET sheet is used. If the Tg exceeds 95 ° C, the sheet should be 3
It is not preferable because the shapeability at the time of dimensioning is deteriorated. On the other hand, when Tc is less than 160 ° C., the whitening suppressing effect during the three-dimensional processing is not substantially recognized as compared with the case where the conventional PET sheet is used, and Not only is it difficult to achieve a high cycle, but it is also difficult to manufacture a thick transparent three-dimensional molded body.
In addition, when Tc exceeds 195 ° C. or when the temperature rising crystallization peak is not observed, the chemical resistance of the three-dimensional molded body is remarkably lowered as compared with the case where the conventional PET sheet is used. Not preferable.

Further, the sheet of the present invention usually has a melting temperature (hereinafter referred to as "Tm") of 20 measured by DSC.
It is in the range of 0 to 245 ° C, preferably 208 to 240 ° C, more preferably 215 to 235 ° C. When the Tm is in this range, the chemical resistance of the three-dimensional molded product obtained by the three-dimensional processing is not substantially deteriorated, which is more preferable. Further, when the Tm of the sheet is within this range, the copolyester itself which is the raw material of the sheet of the present invention also has the crystallinity required for the crystallization treatment and / or the solid phase polymerization treatment. By subjecting the copolyester having a reduced content of acetaldehyde, which causes an offensive odor or taste, to a sheet of the present invention, a transparent sheet having a low acetaldehyde content and further three-dimensional molding thereof by these treatments. The body can be manufactured.

The above Tg, Tc, and Tm measurements were performed using a feather-made stainless steel razor blade without shearing as much as possible from one sheet (weight: 5.
0 mg) was placed in an aluminum pan to prepare a sample
In C, the measurement operation is performed in which the temperature is raised from room temperature to 300 ° C. at a heating rate of 20 ° C./min in a nitrogen atmosphere. Tg
Is obtained from the behavior of the specific heat change due to the glass transition of the calorific curve, and is specifically the temperature at the intersection of the tangent line at the midpoint of the specific heat change due to the glass transition and the tangent line before the specific heat change. Further, Tc is the temperature at which the exothermic amount per unit time is maximum at the exothermic peak derived from crystallization, and Tm
Is the temperature at which the amount of endotherm per unit time is maximum at the endothermic peak due to crystal melting.

Next, the sheet of the present invention has an average thickness of 0.1 to 15 mm. The optimum thickness of the sheet used for the three-dimensional processing is the degree of designing the three-dimensional molded body, that is, the size, thickness, shape, weight, mechanical properties of the three-dimensional molded body to be manufactured and the three-dimensional processing. (For example, the drawing ratio in the drawing process). In general,
For example, as a raw sheet for a draw-formed body or a blow-molded body used as a packaging material, the thickness is usually 0.1 to 0.1.
A transparent sheet having a thickness of 2 mm, preferably 0.15 to 1.5 mm, and more preferably 0.2 to 1.2 mm is used. On the other hand, as a raw sheet for a three-dimensional molded article used for materials such as windows, sunroofs, interiors and exteriors, the thickness is usually 1 to 15 mm, preferably 1.5 to
A transparent sheet having a thickness of 12 mm, more preferably 2 to 10 mm is used. The sheet of the present invention has the same shape except the thickness as compared to the conventional PET transparent sheet.
When manufacturing a three-dimensional molded body, it is possible to manufacture a thicker three-dimensional molded body with good transparency. Further, the sheet of the present invention is characterized in that it is possible to manufacture a three-dimensional molded body having a higher resistance to wet heat deformation than when using a conventional PET transparent sheet, even if the sheet is thinner than the conventional PET transparent sheet. Therefore, when designing a three-dimensional molded body, it is not necessary to increase the thickness for the purpose of improving the resistance to moist heat deformation, which is more than necessary from the viewpoint of mechanical strength. Therefore, weight saving, resource saving, and cost reduction can be achieved. Moreover, it is possible to reduce waste.

The sheet of the present invention is excellent in transparency and has a haze value measured in the thickness direction of the sheet (hereinafter, "measured haze value").
I have to say. ) As 0 to 6%, preferably 0 to
4%, more preferably 0 to 3%, particularly preferably 0 to
2%. Further, regarding the transparency of the sheet of the present invention, the haze value obtained by converting the actually measured haze value into the haze value per 1 mm of the sheet thickness (hereinafter, also referred to as “1 mm haze value”) is 0 to 6%, Preferably 0-4%,
It is more preferably 0 to 3%, particularly preferably 0 to 2%. When the actually measured haze value and / or the 1 mm haze value exceeds 6%, the whitening improvement in the three-dimensional processing is substantially not recognized.

The above-mentioned sheet of the present invention can be produced by sheet-forming a copolyester produced by melt polymerization or subsequent solid phase polymerization according to a conventionally known method for PET sheets. it can. Composition of raw material copolyester,
That is, the copolymerization component is substantially the same as the sheet of the present invention. Further, the intrinsic viscosity generally tends to be slightly lowered due to the influence of hydrolysis or thermal decomposition during the production of the sheet, and therefore, the intrinsic viscosity is usually 0.01 to 0 than the intended intrinsic viscosity of the sheet of the present invention. Copolymerized polyester having a high intrinsic viscosity of 0.05 dl / g is used as a raw material.

Regarding the thermal characteristics of the raw material copolyester, any material may be used as long as the sheet of the present invention can be obtained. Above all, the raw copolyester sample is melted by DSC and then re-cooled. Is the glass transition temperature (hereinafter referred to as “Tg ′”) in the range of 80 to 100 ° C., preferably 82 to 95 ° C. and the absence of a crystallization peak when measured at elevated temperature? , Or even if there is a crystallization peak (below,
It is called "Tc '". Is particularly preferably used in the range of 170 to 220 ° C, preferably 180 to 220 ° C. When the copolyester has the above-mentioned thermal characteristics, it is more preferable because the transparent sheet of the present invention has high productivity.

In the present invention, the measurement of Tg 'and Tc' is performed using a stainless steel razor blade made by Feather and cutting one piece without shearing as much as possible (weight: 5.0 m).
A sample prepared by placing g) in an aluminum pan was once heated from room temperature to 300 ° C. at a temperature rising rate of 20 ° C./min in a nitrogen atmosphere in DSC, and subsequently melt-held at 300 ° C. for 10 minutes. After that, the sample is immediately taken out to the outside, immersed in liquid nitrogen and held for 1 minute, and then at room temperature for 30 minutes to 1 minute.
The sample is left standing for a period of time, returned to room temperature, returned to the apparatus, and again heated from room temperature to 300 ° C. at a heating rate of 20 ° C./min. Tg ′ is obtained from the behavior of the specific heat change due to the glass transition of the calorific curve in the reheating process, and specifically, the intersection of the tangent line at the midpoint of the specific heat change due to the glass transition and the tangent line before the specific heat change. Is the temperature of. Also, T
c ′ is the temperature at which the exothermic amount per unit time becomes maximum at the exothermic peak derived from crystallization during the reheating process.

Usually, the raw material copolyester has a polymer skeleton such as manganese, cobalt, zinc, antimony, germanium, titanium and other metal elements derived from the catalyst used, and phosphorus elements derived from the stabilizer, etc. One or more kinds of elements other than the above are included. There is no particular limitation on the type and amount of these contained elements as long as they do not exceed the constitutional requirements of the present invention, but from the viewpoint of color tone, antimony or germanium, more preferably as an element derived from the polycondensation catalyst, and more preferably. A copolyester using germanium is used.

The above-mentioned copolyester is produced by melt polymerization or by subsequent solid phase polymerization according to a conventionally known method for PET. As the melt polymerization method, for example, a method of directly conducting an esterification reaction using a dicarboxylic acid and a diol, then further raising the temperature and gradually reducing the pressure to cause a polycondensation reaction, so-called T
Examples of the PA method include a method in which an ester derivative of a dicarboxylic acid, such as dicarboxylic acid dimethyl ester, is used for a transesterification reaction with a diol, and then the resulting reaction product is further subjected to a polycondensation reaction, a so-called DMT method. The copolyester produced by these melt polymerization methods is usually further subjected to solid phase polymerization treatment in the form of transparent amorphous pellets or in the state of being crystallized.

When the copolyester is subjected to a solid phase polymerization treatment, the oligomer content or acetaldehyde content in the sheet of the present invention is small because the oligomer content or acetaldehyde content is small. The content can be reduced, and therefore, the contamination of the processing apparatus with oligomers when the sheet is three-dimensionally processed can be reduced, and the acetaldehyde content of the three-dimensional molded body can be reduced. In particular, when the three-dimensional molded product using the sheet of the present invention is used as a packaging material that directly contacts food,
The acetaldehyde content in the sheet is usually 0 to 50 p
pm, preferably 0 to 30 ppm, more preferably 0
It is desirable to set the content in the range of ˜20 ppm so that the contents in the packaging material will not change in taste and odor.

Next, the method for producing the sheet of the present invention will be described in detail. The sheet of the present invention can be produced by a melt molding method which has been conventionally used for forming a sheet of PET or polycarbonate. As these melt molding methods, extrusion molding, press molding and the like are used. For example, when the transparent sheet of the present invention is produced by extrusion casting, the raw material copolymerized polyester is usually supplied to the hopper of a single-screw or twin-screw extruder to which a T die is connected via a gear pump, and extrusion is performed. It can be manufactured by melting in a cylinder of a machine, extruding it into a sheet form from a T-die, and cooling it with a casting roll.

The molding temperature in this case, specifically, the temperature of each part of the cylinder of the extruder, the gear pump, and the T-die is usually 22.
Since it is in the range of 0 ° C to 290 ° C, preferably 230 to 280 ° C and can be set lower than in the case of PET, it is possible to suppress thermal deterioration of the copolyester to a low level. The surface temperature of the casting roll is usually 15 to 70 ° C,
Preferably, it may be controlled at 20 to 60 ° C.

The extruder used for extrusion cast molding may or may not have a vent port in the cylinder part. Since the raw material copolyester generally contains several hundred to several thousand ppm of water, when using an extruder without a vent port, the copolyester is prevented from being hydrolyzed in the cylinder. The copolymerized polyester (1) is dried to have a water content of usually 100 ppm or less, preferably 50 ppm or less, and then supplied to the hopper. When an extruder with a vent port is used, the pressure inside the cylinder can be reduced and the copolyester can be dried inside the cylinder. Volatile impurities such as acetaldehyde contained in the polyester can be reduced in the cylinder. The vent port is usually 0 to 7,000 Pa, preferably 0 to 300
It is used by connecting to a reduced pressure system of 0 Pa, more preferably 0 to 700 Pa. Further, when the twin-screw extruder is used, the screw may be a meshing type, a non-meshing type, or an incomplete meshing type.

Regarding the T-die, the melt may be discharged from the lip in the horizontal direction or the vertical direction. Further, an auxiliary device such as a filter or a sampling valve may be connected between the T die and the extruder. As for the casting roll, it is desirable to have a contact device such as an electrostatic contact device or a touch roll. Moreover, when manufacturing a transparent sheet having a thickness of more than 2 mm, a multistage cooling roll or the like is usually used.

The sheet of the present invention is finally obtained by cutting the both ends of the sheet with a trimming cutter after passing through a casting roll and then winding it into a roll or cutting it into a panel. In particular, in the case of a sheet having a thickness of 2 mm or more, it is difficult to wind it into a roll shape, and even when it is wound, it is difficult to apply it to three-dimensional processing due to its strong curl. It is desirable to cut it into a panel and commercialize it as a cut plate. Further, in the case of a cut plate, it is desirable to cover the surface with a protective sheet to form a product in order to prevent the surface from being scratched and scratched.

The sheet of the present invention has a Tc within a specific range as described above. This Tc is controlled by the intrinsic viscosity of the copolyester as a raw material and Tc ', and the shear history during sheet formation is Is controlled by the size and the degree of formation of the crystal nucleus precursor. The sheet produced under the condition where the shear history is considered to be large or the condition where the degree of formation of the crystal nucleus precursor is considered to be high tends to have a lower Tc. These molding controls include screw shape and rotation speed, die shape, filter and gear pump shape, temperature setting and time setting, extrusion speed, take-up speed, casting roll temperature, and vent port decompression degree. Done by adjustment. For example, in the same apparatus, the shearing history increases as the extrusion speed and the take-up speed increase, and the crystal nucleus precursor generation degree increases as the casting roll temperature increases.

The thus-obtained sheet of the present invention has resistance to heat and moisture deformation, transparency, impact resistance, chemical resistance, thermal stability, gas barrier property, ultraviolet ray blocking property, heat sealing property,
A three-dimensional molded product having excellent recyclability can be provided with good productivity. More specifically, by subjecting the sheet of the present invention to three-dimensional processing, it is less likely to be deformed even when exposed to a high temperature and high humidity environment for a long time, as compared with the case where a conventional polyester transparent sheet is used. It is possible to manufacture a transparent three-dimensional molded body having improved properties. Further, since the sheet of the present invention is suppressed in whitening during the three-dimensional processing as compared with the conventional polyester transparent sheet, a transparent three-dimensional molded body can be molded in a high cycle and the thickness is large. It is possible to easily manufacture a three-dimensional molded body having excellent transparency.

The definition of three-dimensional forming or three-dimensional processing in the present invention is that a sheet which is originally a two-dimensional shape is heat-processed at a temperature lower than its melting temperature to obtain a molded article having a stable three-dimensional shape at room temperature. It refers to the processing, specifically, drawing processing,
Bending, twisting, blow processing, etc. can be mentioned.

In drawing the sheet of the present invention, any method conventionally known as a drawing method of a polyester sheet may be used. Examples of the drawing method include vacuum forming, pressure forming, snapback forming, revers draw forming, air slip forming, plug assist forming, and a combination of these processing methods. Good. The processing temperature is a sheet temperature of usually 80 to 150 ° C., preferably 90.
˜140 ° C., and the drawing ratio is usually 0.01 to 10 times, preferably 0.05 to 5 times. Regarding the sheet temperature, the temperature may differ between the surface and the inside of the sheet,
It is desirable to process all the parts to be processed within the above temperature range. Further, it is generally desirable that the sheet temperature is such that the temperature unevenness in the thickness direction is as small as possible. In particular, the transparent sheet of the present invention is processed under the condition that the temperature unevenness is larger than that of the PET sheet. Also, since it has a feature that it is possible to provide a drawn product having excellent transparency in which whitening is suppressed, it is possible to shorten the temperature rising time of the sheet by setting the temperature of the preheating heater at the time of drawing processing high. Therefore, the productivity of the drawn product can be improved.

In bending or twisting, the sheet temperature is usually 80 to 150 ° C., preferably 90 to 140 ° C., and then stress is applied to one side or both sides to form the shape along the mold. It is common. Regarding the sheet temperature, the temperature may be different between the surface and the inside of the sheet, but it is desirable that all the portions to be processed are processed within the above temperature range. Furthermore, the seat temperature is
Generally, it is desirable to reduce the temperature unevenness in the thickness direction as much as possible. In particular, the sheet of the present invention is made of PET.
Compared with the sheet, even if processed under conditions of greater temperature unevenness, because it has a feature that it is possible to provide a bent molded article and a twist molded article having excellent transparency with suppressed whitening,
By setting the temperature of the heater for preheating at the time of these processings high, the heating time of the sheet can be shortened, and the productivity of these molded products can be improved. The stress applied during processing is generally applied directly from the mold, but it may also be applied by means such as compressed air or vacuum, or a combination thereof. The bending angle, the twisting angle, and the radius of curvature at the time of processing are not particularly limited, and may be set according to the target final shape.

In the blow processing, after the sheet temperature is usually 80 to 150 ° C., preferably 90 to 140 ° C.,
It is blown into a predetermined mold to have a shape along the mold. At this time, for example, the blowing property can be improved by mechanically extending the sheet in the direction perpendicular to the sheet surface by the rod at the start of blowing. Further, by forming the mold as a split movable mold as exemplified by a mold for stretch blow for PET bottles, it is possible to obtain a molded product having an opening smaller than the cross section of the main body. Regarding the sheet temperature, the temperature may be different between the surface and the inside of the sheet, but it is desirable that all the portions to be processed are processed within the above temperature range. Further, it is generally desirable that the sheet temperature is such that the temperature unevenness in the thickness direction is as small as possible. In particular, the transparent sheet of the present invention is processed under the condition that the temperature unevenness is larger than that of the PET sheet. Also,
Because of the feature that it is possible to provide a blow-molded body that is suppressed in whitening and has excellent transparency, the temperature of the heater for preheating during processing can be set high to shorten the heating time of the sheet, The productivity of the molded product can be increased. By blow-processing a sheet, a large blow-molded article, which has been very expensive in the conventional blow-molding of an injection-molded article, can be manufactured at a low cost with high productivity.

The draw-formed product obtained by subjecting the sheet of the present invention to three-dimensional processing has high resistance to moisture and heat deformation such as packaging materials, windows, sunroofs, interiors and exteriors that are exposed to high temperature and high humidity environments. It is suitable as a required transparent material. First, for the packaging material that is one of the applications of the sheet of the present invention, for example, food packaging trays and cups for side dishes, fruits, dumplings, tea bags, etc., and their lids, for packaging electronic components, etc. Examples include industrial trays used, blister packages for toothbrushes and headphones, and packaging cases for gifts and character goods. By using the transparent sheet of the present invention for these packaging materials, it has an advantage that it is difficult to be deformed even when it is held in a high temperature and high humidity environment during transportation or storage. Usually, these packaging materials are those of the sheet of the present invention having a thickness of 0.1 to 2 mm,
It consists of a molded product obtained by three-dimensional processing such as drawing and blow processing, and the thickness is generally 0.05 to 1.5 m.
m.

Next, as a transparent material for a thick window, a sunroof, an interior, an exterior, etc., in which the sheet of the present invention is used, for example, a window or door of a bathroom, a shower room, a solarium, a light bulb or a brooch type. Covers for lighting equipment such as fluorescent lights, car windows and sunroofs,
Transparent materials for lighting, see-through, lighting, display, etc., such as transparent windows for electric appliances such as automatic dishwashers and microwave ovens, road display devices, indoor parking lots and car wash lots, gas station guide plates, etc. Can be mentioned. In addition to these applications, cooking utensils such as bowls, kitchen trays and jelly cups, and storage and transportation products such as cases and containers and bags can be cited. By using the sheet of the present invention for these thick transparent materials, there is an advantage that it is difficult to deform even when it is repeatedly used for a long period of time under a high temperature and high humidity environment. Usually, these transparent materials are molded articles obtained by subjecting the transparent sheet of the present invention having a thickness of 1 to 15 mm to three-dimensional processing such as drawing, bending, twisting and blowing. And has a thickness of 0.8 to 10 mm.

Further, the sheet of the present invention can be used as it is as a transparent material for daylighting, see-through, illumination, display, etc. without being subjected to three-dimensional processing. The copolyester used in the sheet of the present invention is compatible with PET in any proportion when mixed in a molten state, so that the PET
As a result, it is possible to easily recycle the material, and it is also possible to apply the chemical recycling performed by PET, which is represented by the methanolysis method, the glycolysis method or the like, under the same conditions. Therefore, the sheet of the present invention and the three-dimensional molded body using the sheet have high recyclability and also have an effect of suppressing the influence on the environment to be small.

[0044]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. <Measurement Method and Calculation Method> The measurement method and calculation method used in this example are shown below. The method for measuring the intrinsic viscosity is as described above.

(1) Copolymerization component 10 mg of a polyester sample was deuterated with 2,2,2-trifluoroacetic acid / deuterated chloroform (volume ratio = 1 /
The product dissolved in 1 cc of the mixed solvent of 3) was subjected to proton NMR measurement at 23 ° C. using an AM500 type NMR apparatus manufactured by Bruker Co. to identify the copolymerization component and to quantify the content.

(2) Measured Haze Value and 1 mm Haze Value The measured haze value was measured by cutting out a test piece of 3 to 6 cm square from a sheet and using a HGM-2DP type direct reading haze computer manufactured by Suga Test Instruments Co., Ltd. Further, the 1 mm haze value was calculated from the measured haze value and the thickness of the measurement site using the following formula.

[0047]

## EQU1 ## K = 100-100 × {(100-H) / 100} ^{1 / S In} this formula, K is a 1 mm haze value (unit:%), H is a measured haze value (unit:%), and S is It is the thickness (unit: mm) of the site where the actually measured haze of the sample was measured. (4) DSC measurement Using a TA2000 type thermal analyzer manufactured by TA Instruments, the measurement was performed by the measurement method as described above.

<Test Method> The test method used in this example is shown below. (1) Moisture and heat deformation resistance test The maximum temperature at which substantially no deformation was observed when a three-dimensional molded body was allowed to stand in an environment with a relative humidity of 90% for 24 hours was defined as the humidity and heat deformation resistance temperature. The test temperature is 2 ℃
It was set as the temperature at every step (even temperature). The higher the moisture-heat deformation resistance temperature, the higher the moisture-heat deformation resistance.

(2) Impact resistance test Ten three-dimensional molded bodies as they are, or in a state of being filled with water, in an environment of a temperature of 23 ° C. and a relative humidity of 50%, a height of 2 m
Alternatively, from the position of 3 m, it was continuously dropped 5 times on concrete with a smooth surface, and the number of cracks generated during that period was used as an index of impact resistance. The smaller the number of cracks, the higher the impact resistance.

<Raw Material Polyester> The raw material polyester used for sheet formation in this example is shown in Table 1.

[0051]

[Table 1]

[Example 1] The raw material polyester C-2 shown in Table 1 was used as a sheet forming device, and a gear pump, a filter, a T-die, and the like were connected to TEX6 manufactured by Japan Steel Works Ltd.
5 type 65mmφ direction twin screw extruder (with vent port), set temperature 280 ° C, vent port internal pressure 1m
The sheet was extruded under a condition of mHg or less and wound through a casting roll (with a touch roll) having a surface temperature of 40 ° C. to form a sheet having a thickness of 600 μm. Table 2 shows the physical property values of the sheet.

Next, the sheet was heated for 4 hours by using a plug-assist type vacuum pressure forming machine manufactured by Asano Laboratory.
Second, under the conditions of a sheet surface temperature of 135 ° C. and a mold temperature of 40 ° C., the bottom surface is a rectangle of 11 cm in length and 14 cm in width, and the upper end opening is a rectangle of 12.5 cm in length and 15.5 cm in width, and the height is Is a truncated pyramid shape of 3 cm (drawing ratio = 0.
24) and adjacent to the outside of the opening with a flat flange having a width of 5 mm. The draw-formed product was excellent in transparency, had well-formed sides and corners, had sufficient tactile strength, and was good in appearance. Table 1 shows the results of the wet heat deformation resistance test and the impact resistance test performed on the drawn molded product.
It is shown in FIG. In the impact resistance test, the undrawn sheet is attached to the flange of the drawn body, and the inside of the drawn body is filled with demineralized water and is allowed to freely fall from a height of 2 m with the bottom face down. It was carried out by

[Examples 2 to 4] Using the copolyesters shown in Table 2, the same operations as in Example 1 were carried out to form a sheet and a draw-formed product. However, in Example 2, the molding temperature at the time of sheet molding was 275 ° C. Table 2 shows the physical property values of these sheets and the test results of the drawn and molded products. The impact resistance test was carried out under the same conditions as in Example 1. In addition, each of the obtained draw-formed products had the sides and corners firmly formed, had sufficient tactile strength, and had a good appearance.

[Comparative Examples 1 to 6] Using the copolyesters shown in Table 2, a sheet and a draw-molded body were molded in the same manner as in Example 1. However, in Comparative Example 4, the molding temperature at the time of molding the transparent sheet was 265 ° C. Table 2 shows the physical property values of these transparent sheets and the test results of the drawn and molded products. The impact resistance test was carried out under the same conditions as in Example 1. The draw-formed body obtained in Comparative Example 1 was slightly whitened and cloudy, which was not preferable in appearance. Further, the draw-formed bodies obtained in Comparative Example 3 and Comparative Example 4 were clearly whitened to be frosted glass,
It was not desirable in appearance. Comparative Examples 3 to 5
In the impact resistance test of the draw-formed body of No. 3, it was found that the content liquid leaked due to cracking during five consecutive drops.

[0056]

[Table 2]

[Embodiment 5] In the sheet molding of Embodiment 1, the T die is made of T with a large opening for slits for board molding.
The die was replaced, and the cooling roll was a double-sided cooling type three-stage roll, and the same operation as in Example 1 was carried out to form a sheet having a thickness of 3 mm. At this time, the sheet was obtained as a panel-shaped cut plate without being wound up. Table 3 shows the physical property values of the sheet.
Then, the sheet was subjected to a drawing process under the conditions of a sheet heating time of 30 seconds, a sheet surface temperature of 130 ° C., and a mold temperature of 30 ° C. in the same manner as in Example 1 to obtain a drawn molded product.
The draw-formed product was excellent in transparency, had well-formed sides and corners, had sufficient tactile strength, and was good in appearance. Table 3 shows the results obtained by performing a wet heat deformation resistance test and an impact resistance test on the drawn product. The impact resistance test was carried out by allowing the draw-formed body to drop freely from a height of 3 m.

[Examples 6 to 7] Using the copolymerized polyesters shown in Table 3, the same operations as in Example 5 were carried out to form sheets and draw-formed articles having the thicknesses shown in Table 3. Table 3 shows the physical property values of these sheets and the test results of the drawn and molded products. The impact resistance test was carried out under the same conditions as in Example 5. In addition, each of the obtained draw-formed products had the sides and corners firmly formed, had sufficient tactile strength, and had a good appearance.

[Comparative Examples 7 to 12] The copolymerized polyesters shown in Table 3 were used and the same operation as in Example 5 was carried out.
The sheet and the draw-formed body having the thickness shown in (1) were formed. Table 3 shows the physical property values of these sheets and the test results of the drawn molded product.
Shown in In the drawing of the 6 mm thick sheet obtained in Comparative Example 7, the drawing could not be performed successfully because the crystallization proceeded excessively during the heating of the sheet. Further, the drawn products using the sheet having a thickness of 4 mm obtained in Comparative Example 7 and the drawn products obtained in Comparative Examples 9 and 10 were both whitened and not preferable in appearance. . In addition, in the impact resistance test of the draw-formed products of Comparative Examples 9 to 11, it was confirmed that cracks and cracks were generated during five consecutive drops.

[0060]

[Table 3]

Example 8 Thickness produced in Example 6 3.
A 0 mm sheet is cut into a rectangle with a length of 7 cm and a width of 20 cm, preheated for 20 seconds to bring the sheet surface temperature to 100 ° C., and then bent along the sheet surface with a position of 10 cm from the edge as the center. Then, an L-shaped bent compact having a bending angle of 90 ° C. and a radius of curvature of 2 cm was obtained. The bent body had excellent transparency, sufficient tactile strength, and good appearance. In addition, the moisture-heat-resistant deformation temperature of the bent molded body was 72 ° C.

[Comparative Example 13] Using the sheet having a thickness of 3.0 mm manufactured in Comparative Example 7, L was obtained in the same manner as in Example 8.
A bent bent body was obtained. . The bending molded article is excellent in transparency and has sufficient tactile strength,
Although the appearance was good, the bending heat resistance of the bent molded article was 64 ° C.

[0063]

EFFECTS OF THE INVENTION The copolyester sheet of the present invention is poor in workability and difficult to realize with conventional polyester sheets due to three-dimensional processing such as drawing, bending, twisting and blowing. , A three-dimensional molded body with high resistance to moist heat deformation, high transparency, and a large thickness,
It can be provided with high productivity. The three-dimensional molded body obtained by subjecting the sheet of the present invention to three-dimensional processing has suppressed whitening during the three-dimensional processing, so that a transparent three-dimensional molded body can be molded in a high cycle. It is exposed to high temperature and high humidity environment because it has improved resistance to moisture and heat deformation and transparency, and has excellent impact resistance, chemical resistance, thermal stability, gas barrier property, UV blocking property and heat seal property. It is preferably used as a transparent material such as packaging material, window, sunroof, interior, exterior, cooking utensil, storage article, and transportation article, which is required to have high resistance to heat and heat deformation. Further, the sheet of the present invention can be used as it is as a transparent material for daylighting, see-through, illumination, display, etc. without performing three-dimensional processing. Since the copolyester used in the transparent sheet of the present invention has high recyclability, the sheet of the present invention and a three-dimensional molded article using the same also have an effect of suppressing the influence on the environment to a small extent.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C08J 5/18 CFD C08J 5/18 CFD // B29K 7:00 67:00 C08L 67:00

Claims (6)

[Claims] 1. A terephthalic acid as a dicarboxylic acid component, an ethylene glycol as a diol component as a main component, and a naphthalene dicarboxylic acid as a copolymerization component are contained in an amount of 5 to 25 mol% based on all dicarboxylic acid components. 3)
Diethylene glycol is added to all diol components in 0.1
Content of ~ 5 mol%, (4) intrinsic viscosity 0.5-1.5d
1 / g, (5) glass transition temperature (Tg) is 75 to 95
(6) Temperature rising crystallization temperature (Tc) is 160 to 195
C., (7) thickness is 0.1 to 15 mm, (8) haze value is 0 to 6%, (9) haze value per mm is 0 to 6
%, A copolyester sheet. 2. A terephthalic acid as a dicarboxylic acid component, an ethylene glycol as a main component as a diol component, and a naphthalenedicarboxylic acid as a copolymerization component are 5 to 25 mol% of all dicarboxylic acid components.
(3) Diethylene glycol is contained in an amount of 0.1 to 5 mol% based on all diol components, and (4) the intrinsic viscosity is 0.5 to
1.5 dl / g, (5) Glass transition temperature (Tg ′) after melt quenching treatment is 80 to 100 ° C., (6) Temperature rising crystallization temperature (Tc ′) after melt quenching treatment is 170 to 220 ° C. or The sheet according to claim 1, which is obtained by melt-extruding a copolyester having no crystallization peak. 3. The sheet according to claim 1, wherein the sheet has a melting temperature of 200 to 245 ° C. 4. A three-dimensional molded body obtained by drawing the sheet according to claim 1. 5. A three-dimensional molded body obtained by bending and / or twisting the sheet according to any one of claims 1 to 3. 6. A three-dimensional molded body obtained by blow processing the sheet according to any one of claims 1 to 3.