JP2019081377A - Thermoplastic resin sheet and molded article obtained by heat-molding the same - Google Patents

Abstract

To provide a transparent resin sheet that is capable of being formed into a film by a general-purpose casting facility, and that is capable of producing a molded article having high transparency and excellent heat resistance even after heat molding.SOLUTION: A thermoplastic resin composition sheet comprising: at least one kind of a resin composition A selected from a group consisting of a polypropylene resin having a crystallization rate of 0.9 minor more and 3.0 minor less, a polybutylene terephthalate resin, a polyethylene terephthalate resin, a nylon 6 resin and a nylon 66; and a sheet thickness of 10 to 500 μm; a theoretical layer thickness obtained by dividing the sheet thickness by a theoretical number of laminations of 0.05 μm or more and 0.5 μm or less; and a plane orientation coefficient ΔP of 0 to 0.01.SELECTED DRAWING: None

Description

  The present invention relates to a thermoplastic resin sheet. More particularly, the present invention relates to a resin sheet suitable for producing a heat-formed article which can be used at high temperature and has high transparency, and a method of producing the same. Although the most typical use of the molded article of the present invention is a food container which can be heated by a microwave oven, it can be widely used for various containers requiring heat resistance and transparency without being limited thereto.

  The resin sheet is used as various protective films to be bonded to the surface of a sealant and a display material, and is also used as a sheet material for heat molding. Among the sheet materials for thermoforming, in applications such as various food containers, for decoration, and for vending machine displays, particularly excellent in transparency are required, and conventionally, the transparency is lowered due to crystallization etc. Sheet materials such as polystyrene (PSt) without concern have been used. However, these materials have heat resistance of only about 100 ° C., and their use at high temperatures such as microwave cooking is limited in heat resistance including mechanical characteristics, such as limited applications such as lid materials, and so on. And there was no balanced material in terms of price.

  For microwave oven compatible food container applications, molded products of crystalline materials with good heat resistance are used, and in particular polypropylene resin (PP) is preferably used from the viewpoint of high crystallinity and heat resistance. . For PP, the film forming method at the time of sheeting or filming is used properly depending on the application, for example, a stretched PP film is used as various packaging materials which do not require moldability, while an unstretched sheet is a sheet material for thermoforming Are widely used. Future lifestyle trends are forecast to increase use of containers capable of high-temperature use that can be microwave-cooked, but PP has large crystals formed during heat-molding and decreases transparency due to molding As a result, there is a problem that it is not preferable when the container is required to have high transparency in terms of design.

  Several techniques have been disclosed for these issues. According to Patent Document 1, it is possible to suppress whitening during molding and obtain a molded body having high transparency by blending a petroleum resin and a nucleating agent into PP and forming a sheet by using a quenching process at the time of casting. Discloses a technique for producing a transparent sheet. However, in the prior art, if the mold temperature is lowered at molding in order to maintain the transparency of the molded product, the heat resistance of the molded product decreases with the decrease of the crystallinity degree, and the heat resistance of the molded product There is a problem that raising the temperature of the mold at the time of molding to increase the moldability lowers the transparency of the molded product, making it difficult to achieve both moldability and heat resistance. In addition, since special film forming equipment such as a belt process is required for rapid cooling at the time of casting, there is also a problem that sheet production in a general-purpose film forming equipment is difficult.

  In addition, there is known a technology for producing a PP sheet which is excellent in flexibility and has a relatively good balance of moldability and heat resistance by means of inflation film formation (see Patent Document 2). However, such prior art is insufficient in transparency of the sheet, and is not suitable for forming a thick sheet suitable for heat forming.

  On the other hand, in the case of a polyester heat-forming sheet, there is known a technique in which a PET resin called a CPET, which contains a nucleating agent for promoting crystallization, is sheet-formed and heat-formed (see Patent Document 3). However, in such conventional techniques, although heat resistance is greatly improved as compared with a molded product obtained by heat-forming a normal PET sheet, spherulites develop to be opaque and the impact resistance at low temperature is greatly reduced. Further, there is a problem that when molding temperature is lowered and molding is performed in order to solve these problems, the formability and the heat resistance decrease.

  Therefore, it is known that the heat resistance can be improved by stretching the sheet at a low magnification to cause oriented crystallization within a range in which the formability does not decrease, and that the decrease in transparency can be suppressed by the refinement of crystals formed. (See Patent Document 4). However, such conventional techniques require equipment for suppressing shrinkage during heating and molding, and there is a restriction in terms of equipment for manufacturing sheets that stretching equipment becomes large when manufacturing thick sheets. There was a point.

JP, 2012-139826, A Re-table 99/007752 gazette JP 2000-355091 A JP, 2011-245643, A

  The present invention has been made on the background of the problems of the prior art. That is, an object of the present invention is a transparent resin sheet which can be formed into a film by a general-purpose casting equipment, and is transparent which can produce a molded article having high transparency and excellent heat resistance even after heat molding. It is providing a resin sheet.

As a result of intensive studies to achieve such an object, the present inventors have completed the present invention.
That is, the present invention
<1> At least one selected from the group consisting of a polypropylene resin, a polybutylene terephthalate resin, a polyethylene terephthalate resin, a nylon 6 resin, and a nylon 66 having a crystallization rate of 0.9 min-1 to 3.0 min-1 The thickness of the sheet is 10 to 500 μm, the thickness of the theoretical layer is 0.05 μm to 0.5 μm, and the plane orientation coefficient ΔP is 0 to 0. The thermoplastic resin composition sheet which is 01.
<2> A polypropylene resin composition A having a crystallization rate of 0.9 min-1 to 3.0 min-1 and a polypropylene resin composition B having a crystallization rate equal to or less than the crystallization rate of the polypropylene resin composition A A thermoplastic resin having a sheet thickness of 10 to 500 μm, a theoretical layer thickness obtained by dividing the sheet thickness by the number of theoretical laminations of 0.05 μm to 0.5 μm, and a plane orientation coefficient ΔP of 0 to 0.01 Composition sheet.
<3> The haze is 0.1 to 20%, and the rise in the haze (unit:%) when heated at a temperature rising crystallization temperature for 10 minutes is 10 points or less; described in <1> or "<2> Thermoplastic resin composition sheet.
The molded article obtained by heat-molding the thermoplastic resin composition sheet in any one of <4><1>-<3>.
The food container obtained by heat-molding the thermoplastic resin composition sheet in any one of <5><1>-<3>.

  The present inventors divide the molten resin composition into 200 or more layers in the thickness direction of the film, and after laminating, in the extruded sheet formed by extrusion from a die, between the laminated layer and the layer It has been found that the interface has the effect of acting as a crystallization initiation point. In addition, since the interface is crystallized earlier than other portions, the vicinity of the interface becomes a wall, and crystal growth is divided by the wall, and further, crystals can not grow beyond the thickness of the interface due to the division. I found that. In addition, it was also found that by increasing the number of interfaces, the number of crystallization start points increases and the distance between the interfaces decreases. As a result, it has been found that the size of spherulites can be suppressed to a small size even after heat forming at a high temperature such as vacuum forming, and a sheet with high transparency can be obtained.

  The present invention provides a transparent resin sheet that can be formed into a film by a general-purpose casting facility, and can produce a molded article having high transparency and excellent heat resistance even after heat molding. can do.

The present invention has a sheet thickness of 10 to 1000 μm having at least the following step (1), step (2) and step (3), and has a theoretical layer thickness of 0.5 μm or less obtained by dividing the sheet thickness by the number of theoretical layers. It is a manufacturing method of a certain thermoplastic resin composition sheet.
Step (1): The thermoplastic resin composition A having a crystallization rate of 0.9 min-1 or more and 3.0 min-1 or less is melted to form a molten fluid A1.
Step (2): forming a laminated fluid A2 composed of the molten fluid A1 and having a laminated number of 200 or more.
Step (3): The laminated fluid A2 is discharged from a die and brought into contact with a cooling roll to solidify. Further, the present invention has a sheet thickness of 10 to 1000 μm at least including the following step (1A), step (1B), step (2) and step (3), and is a theoretical layer obtained by dividing the sheet thickness by the number of theoretical layers. It is a manufacturing method of the thermoplastic resin composition sheet whose thickness is 0.5 micrometer or less.
Step (1A): A thermoplastic resin composition A having a crystallization rate of 0.9 min-1 or more and 3.0 min-1 or less is melted to form a molten fluid A1.
Step (1B): A thermoplastic resin composition B having a crystallization rate equal to or less than the crystallization rate of the thermoplastic resin composition A is melted to form a molten fluid B.
Step (2): forming a laminated fluid AB2 having 200 or more layers of lamination comprising the molten fluid A1 and the molten fluid B1.
Step (3): The laminated fluid AB2 is discharged from a die and brought into contact with a cooling roll to solidify.

  The present invention will be described in detail below.

(Thermoplastic resin composition)
The thermoplastic resin composition A and the thermoplastic resin composition B used in the present invention are composed of a thermoplastic resin, or a thermoplastic resin as a main component and other components. Hereinafter, the thermoplastic resin composition A and the thermoplastic resin composition B will be collectively referred to as a thermoplastic composition in the present invention.

Examples of the thermoplastic resin that can be used for the thermoplastic resin composition in the present invention include polypropylene, polyethylene, polybutylene terephthalate, nylon 6 and the like. Specifically, polypropylene includes Nobrene manufactured by Sumitomo Chemical Co., Ltd., primed polypropylene manufactured by Sumitomo Polymer, polypropylene manufactured by Sun Aromaer, etc., polyethylene as Novatec LL / HD manufactured by Japan Polyethylene, and Hyzex / Neozex manufactured by Prime Polymer. In addition, as polybutylene terephthalate, Mitsubishi Engineering Plastics made by Nova Duran, Wintech polymer made by Juranex, Toray made by Toray, Toraycon made by Japan GE Plastics, etc. as polyethylene terephthalate such as Toyobo, manufactured by Nihon Unipet, etc. And recycled PET resin. Furthermore, Toyobo's Gramide as nylon 6, UBE nylon, UBE nylon etc., nylon 66 as Asahi Kasei Leona, Toray's Amiran, Ube Industries UBE nylon 66, BASF Ultramit, copolyamide such as copolyamide Alchema's Rilsan Daissel Evonik Vestamide / Diamide, Sumitomo Chemical's Sumika Super LCP, Polyplastics's Vectra, etc., Polyplastics Sulfide, DIC's PPS resin, Polyplastics 'Fortlon, etc. Polycarbonate, Teijin Chemicals' Panlite And Mitsubishi Engineering Plastics's Iupilon, Sumika Styron Polycarbonate Gulliver, and polyphenylene ether.
These resins may be used alone or in combination of two or more.

  Examples of other components that can be used for the thermoplastic resin composition in the present invention include crystallization nucleating agent addition and amorphous polymers. The other component may be a thermoplastic resin different from the thermoplastic resin as the main component.

  As the crystallization nucleating agent, there are phosphoric acid ester salt type, sorbitol type, carboxylic acid salt type, etc. from the structural classification, and specifically, there are Adeka made Adekastab NA series, Gelall of Shin Nippon Rika, RIKAFAST etc. . Moreover, copolymerized polyester, a polycarbonate, etc. are mentioned as an amorphous polymer. Specific examples of the copolyester include polybasic carboxylic acids other than terephthalic acid such as isophthalic acid, orthophthalic acid, succinic acid, sebacic acid and cyclohexyl dicarboxylic acid, diethylene glycol, neopentyl glycol, 3-methyl-1,5-pentane A copolymer of diol, bisphenol A alkylene oxide adduct, cyclohexane dimethylol and the like can be used. Specific examples of polycarbonates include Sumika-Stylon Gulliver, SD Polyca, Mitsubishi Engineering Plastics Iupilon, Novarex and the like, Teijin Chemical-made pan light, Idemitsu Chemical Taflon. The content of the crystallization nucleating agent is preferably in the range of 1 to 10% by weight with respect to the entire thermoplastic resin composition. The content of the non-crystalline polymer is preferably in the range of 050% by weight, preferably 0 to 45% by weight, based on the total weight of the thermoplastic resin composition. If it exceeds 50 parts by weight, it is not preferable because the crystallinity is lowered and the heat resistance is lowered.

  As other components that can be used for the thermoplastic resin composition in the present invention, various additives can be mentioned. Examples of additives include plasticizers, mold release agents, flame retardants, lubricants, colorants (dyes, pigments), antistatic agents, antifogging agents, adhesion promoters and the like. These additives can be suitably used according to the purpose. The lower limit of the additive amount (% by weight) of the additive is preferably 0, more preferably 0.01, and still more preferably 0.05. It is preferable that these addition amounts be adjusted appropriately according to the purpose. The upper limit of the additive amount (% by weight) is preferably 10, more preferably 8, and further preferably 5. If the above is exceeded, the physical properties of the resin will be greatly degraded, and the appearance may be degraded due to bleed out and the like.

  The other components that can be used in the thermoplastic resin composition of the present invention may be used as they are, together with the resin, put into the extruder for use, but may be mixed with the resin in advance to be used as a masterbatch. . As an example of the masterbatch containing a crystallization nucleating agent, Dainichiseika Clearmaster and the like can be mentioned.

  As the thermoplastic resin in the present invention, one having a specific crystallization rate range is used. The crystallization rate referred to here is P. Y. 117 listed as reference 121 P. Khanna: Polym. Eng. & Sci. , 24, 1615 (1990) were used as a reference. An example of a specific measurement procedure is shown separately in the section of Examples.

  The lower limit of the crystallization rate (min-1) of the thermoplastic resin composition A in the present invention is 0.9, preferably 1.0, and more preferably 1.2. If it is less than the above, crystallization tends to be slow, and the heat resistance of the obtained sheet tends to be poor. The upper limit of the crystallization rate (min-1) of the thermoplastic resin composition is 3.0, preferably 2.9, and more preferably 2.8. If the crystallization rate is too high, the crystallization may be too fast, the transparency of the obtained sheet may be reduced, and the moldability may be inferior. In addition, the molding temperature range of the obtained sheet may be narrowed.

  The lower limit of the crystallization rate of the thermoplastic resin composition B in the present invention is not particularly limited. On the other hand, the upper limit of the crystallization rate (min-1) of the thermoplastic resin composition B in the present invention is the crystallization rate of the thermoplastic resin composition A in the present invention.

  Although the lower limit of the melt viscosity (MFR) of the thermoplastic resin composition in the present invention is not particularly limited, it is preferably 0.01 g / 10 min, more preferably 0.05 g / 10 min, and still more preferably 0. .10 g / 10 min. When it is less than the above, the melt viscosity may be too high, and the productivity at the time of molding may be reduced. The upper limit of the melt viscosity (MFR) of the resin composition is preferably 50, more preferably 45, and still more preferably 40. When the above is exceeded, the pressure at the time of discharge is too low, and it may be difficult to cast with uniform thickness. In addition, MFR in this invention is taken as the value measured by the method of JISK7210: 2014.

  The lower limit of the melting point (° C.) of the thermoplastic resin composition in the present invention is preferably 100, more preferably 110, and still more preferably 120. If it is less than the above, the heat resistance may be poor and the application may be limited. The upper limit of the melting point (° C.) of the resin composition is preferably 350, more preferably 340, and still more preferably 330. If the temperature exceeds the above range, the heat resistance effect may be saturated, and the process temperature needs to be increased during sheet production and production of a sheet heat-formed product, and a corresponding production facility is required. . As the melting point of the thermoplastic resin composition in the present invention, a melting endothermic peak temperature detected when 10 mg of the thermoplastic resin composition is heated at a temperature rising rate of 20 ° C./min using a DSC device is used. Do.

(Method of producing thermoplastic resin composition sheet)
The method for producing a thermoplastic resin composition sheet of the present invention is a method for producing a sheet having a sheet thickness of 10 to 1000 μm and a theoretical layer thickness obtained by dividing the sheet thickness by the number of theoretical layers is 0.5 μm or less The step (1) (or the step (1A) and the step (1B)) of melting the thermoplastic resin in the present invention to form a molten fluid, the number of laminations of 200 or more comprising the molten fluid formed in the step (1) The method further comprises at least the step (2) of forming a laminated fluid, and the step (3) of discharging the laminated fluid formed in the step (2) from a die and bringing it into contact with a cooling roll to solidify it. Other steps may be inserted between the step (1) and the step (2) and between the step (2) and the step (3). For example, a filtration step, a temperature change step and the like may be inserted between the step (1) and the step (2). In addition, a temperature change step, a charge addition step and the like may be inserted between the step (2) and the step (3). However, between the step (2) and the step (3), there should not be a step of destroying the laminated structure formed in the step (2).

  In the step (1) (or the step (1A) and the step (1B)), the method of melting the thermoplastic resin in the present invention to form a molten fluid is not particularly limited, but preferred methods include a single screw extruder and The method of heat-melting using a twin-screw extruder can be mentioned.

  The method for forming the laminated fluid in step (2) is not particularly limited, but the molten resin composition is passed through any one or more of a static mixer, a multilayer feed block and a multilayer manifold installed in a melt line. It is preferable to When forming a laminated fluid consisting of resin composition A and resin composition B, the resin compositions formed in step (1A) and step (1B) are merged to form a resin composition consisting of two layers first Then, it is preferable to pass the molten resin composition through any one or more of a static mixer, a multilayer feed block and a multilayer manifold installed in the melt line.

  The method for forming the laminated fluid in step (2) is not particularly limited, but a static mixer and / or a multilayer feed block is more preferable from the viewpoint of facility simplicity and maintainability. Further, from the viewpoint of uniformity in the sheet width direction, one having a rectangular melt line is more preferable. It is further preferred to use a static mixer or multilayer feed block with rectangular melt lines. The resin composition composed of a plurality of layers formed by combining a plurality of resin compositions may be passed through any one or two or more of a static mixer, a multilayer feed block and a multilayer manifold.

  The theoretical number of layers in step (2) needs to be 200 or more. The lower limit of the theoretical stacking number is preferably 500, and more preferably 1000. If the theoretical number of layers is too small, the effect of accelerating the crystallization is insufficient, or the distance between layer interfaces is long, the crystal size becomes too large, and the effect of the present invention tends not to be obtained. In addition, the transparency after molding may be reduced in the vicinity of both ends of the sheet. The upper limit of the theoretical number of layers in step (2) is not particularly limited, but is preferably 100,000, more preferably 10,000, and still more preferably 7,000. Even if the theoretical stacking number is extremely increased, the effect is saturated and problems may occur in terms of production efficiency.

  When the lamination in step (2) is performed by a static mixer, the number of theoretical laminations can be adjusted by selecting the number of elements of the static mixer. A static mixer is generally known as a static mixer without a drive (line mixer), and the fluid entering the mixer is sequentially stirred and mixed by the elements. However, when the high viscosity fluid is passed through a static mixer, division and lamination of the high viscosity fluid occur to form a laminated fluid. The high-viscosity fluid is split into two and then merged and stacked each time it passes through one element of the static mixer. Therefore, when the high-viscosity fluid is passed through a static mixer with the number n of elements, a layered fluid with a theoretical number of stacking of N = 2n is formed. It is also possible to use a laminated fluid as the high viscosity fluid that feeds the static mixer. When the number of layers of high viscosity fluid supplied to the static mixer is m, the theoretical number N of layers of laminated fluid is N = m × 2 n.

  A typical static mixer element has a structure in which a rectangular plate is twisted 180 degrees, and depending on the direction of twist, there are right and left elements, and the dimension of each element is 1.5 times the length of the diameter Is based on The static mixer that can be used in the present invention is not limited to such.

  When the lamination in the step (2) is performed with a multilayer feed block, the number of theoretical laminations can be adjusted by selecting the number of divisions / laminations of the multilayer feed block. A plurality of multilayer feed blocks can be installed in series. Further, it is also possible to use the high viscosity fluid itself supplied to the multilayer feed block as a laminated fluid. For example, when the number of layers of high viscosity fluid supplied to the multilayer feed block is p, the number of divisions / layers of the multilayer feed block is q, and the number of multilayer feed blocks installed is r, the number N of layers of laminated fluid is N = p It becomes × qr.

  In step (3), the laminated fluid is discharged from the die and brought into contact with the cooling roll to solidify.

  The lower limit of the die temperature (° C.) is preferably the melting point of the thermoplastic resin used in the thermoplastic resin composition of the present invention, and more preferably the melting point +10. The upper limit of the die temperature (° C.) is preferably the melting point +60, more preferably the melting point +50.

  The lower limit of the cooling roll temperature (° C.) is preferably 5, more preferably 10, and still more preferably 15. If it is less than the above, the effect of quenching is saturated. The upper limit of the cooling roll temperature (° C.) is preferably 60, more preferably 40, and still more preferably 20. If the above is exceeded, it may be necessary to take measures such as wrinkles at the time of cooling in the subsequent facilities.

(Sheet)
The theoretical layer thickness in the present invention is calculated by the following equation.
Theoretical layer thickness = sheet thickness / theoretical stacking number

  The lower limit of the theoretical layer thickness (μm) in the present invention is preferably 0.001, more preferably 0.01, and still more preferably 0.05. If the amount is less than the above, the effect is saturated, which may cause problems in terms of production efficiency. The upper limit of the theoretical layer thickness (μm) is preferably 0.45, more preferably 0.3, still more preferably 0.2, and still more preferably 0.1. If the above is exceeded, the size of the spherulite will increase after molding, and the transparency will decrease.

  The lower limit of the sheet thickness (μm) in the present invention is preferably 10, more preferably 100, and still more preferably 200. If it is less than the above, the strength as a thin molded product may be insufficient and it may not be put to practical use. The upper limit of the sheet thickness (μm) of the present invention is preferably 1000, more preferably 800, and still more preferably 500. When it exceeds the above, the thickness may be too large and the moldability may be reduced.

  In the thermoplastic sheet of the present invention, although it is preferable that the entire cross section of the sheet is filled with the laminated structure of the theoretical number of layers, it is extremely difficult to actually manufacture such a sheet. Therefore, the laminated structure in the vicinity of the surface may be disturbed or another layer may be formed on the surface of the laminated structure as long as the effects of the present invention are not impaired.

  The thermoplastic resin composition sheet of the present invention may be either a laminate of a single resin composition or a laminate of a plurality of resin compositions. When it is a laminate of a single resin composition, the above-described resin composition A is used as a raw material. In the case of a laminate of a plurality of resin compositions, the above-described resin composition A and resin composition B are used as raw materials.

  In the case where layers having a high crystallization rate and a layer having a low crystallization rate are alternately stacked, in the layer having a high crystallization rate, spherulites start to grow from the interface between the layer having a high crystallization rate and the layer having a low crystallization rate. Therefore, a crystal wall is formed at the interface and the crystal growth is divided. In addition, although a layer having a slow crystallization rate is also crystallized later, crystallization is divided at the wall of the crystal.

  The ratio of the theoretical layer thickness of the layer composed of the thermoplastic resin composition A and the layer composed of the thermoplastic resin composition B in the thermoplastic resin composition sheet of the present invention is not particularly limited.

The theoretical thickness of the layer made of the thermoplastic resin composition can be calculated by the following equation.
Theoretical thickness of layer consisting of thermoplastic resin composition A = [sheet thickness × [volume discharge speed of thermoplastic resin composition A / (volume discharge speed of thermoplastic resin composition A + volume discharge of thermoplastic resin composition B Speed)]] / (theoretical stack number / 2)
Theoretical thickness of layer consisting of thermoplastic resin composition B = [sheet thickness × [volume discharge speed of thermoplastic resin composition B / (volume discharge speed of thermoplastic resin composition A + volume discharge of thermoplastic resin composition B Speed)]] / (theoretical stack number / 2)

  The lower limit of the sheet thickness (μm) of the present invention is preferably 10, more preferably 100, and still more preferably 200. If it is less than the above, the strength as a thin molded product may be insufficient and it may not be put to practical use. The upper limit of the sheet thickness (μm) of the present invention is preferably 1000, more preferably 800, and still more preferably 500. When it exceeds the above, the thickness may be too large and the moldability may be reduced.

The upper limit of the plane orientation coefficient ΔP (−) of the sheet of the present invention is preferably 0.1, more preferably 0.09, and still more preferably 0.08. When the above is exceeded, the spreadability at the time of drawing processing may fall, and a moldability may fall. When the molecular chains are oriented parallel to the film surface, the transparency is likely to be improved, but there may be problems in container formation. The plane orientation factor is related to the degree of stretching at the time of film production, and tends to be higher when stretching is added. In the production of the thermoplastic resin composition sheet of the present invention, care must be taken not to carry out excessive stretching.

The lower limit of the haze (%) of the sheet of the present invention is preferably 0, more preferably 0.5. If it is less than the above, the scratch may be noticeable.
The upper limit of the haze (%) of the sheet of the present invention is preferably 20, more preferably 18. When it exceeds the above, the transparency may be lowered and the quality of the container may be lowered.

The lower limit of the degree of crystallinity (%) of the sheet of the present invention is preferably 20, more preferably 25, and still more preferably 30. If it is less than the above, deformation may occur due to the progress of crystallization over time, or heat resistance may be reduced.
The upper limit of the degree of crystallinity (%) of the sheet of the present invention is preferably 80, more preferably 75. If the above is exceeded, the effect is saturated.

  The resin sheet of the present invention preferably has a haze of 10 points or less, which is increased by holding the sheet for 10 minutes at a temperature rising crystallization temperature. The amount of increase in haze is 10 points or less, preferably 8 points or less, and more preferably 5 points or less. When the haze rise exceeds 10 points, the transparency after molding to a container or the like is low, and the object of the present invention is not met. In order to reduce the amount of increase in haze, it is necessary that the size of crystals formed in the crystallization process be small, and it is effective to reduce the thickness of the theoretical layer and to add a crystal nucleating agent.

  In the present invention, the temperature rising crystallization temperature is determined by analyzing the thermoplastic resin sheet using a DSC device and holding it at 30 ° C. high temperature of the melting point of the resin sheet for 5 minutes, and then rapidly solidified at a cooling rate of 20 ° C./min. Then, it is the crystallization peak temperature in the DSC chart obtained by raising the temperature at a heating rate of 20 ° C./min. As the melting point of the resin sheet, a melting endothermic peak temperature detected when 10 mg of the thermoplastic resin composition sheet is heated at a temperature rising rate of 20 ° C./min using a DSC device is used.

  After the sheet of the present invention is formed into a container, the lower limit of the haze (%) is preferably 1, more preferably 1.5, and still more preferably 1.5. If it is less than the above, the scratch may be noticeable.

  After the sheet of the present invention is formed into a container, the upper limit of the haze (%) is preferably 20, more preferably 18, and particularly preferably 15. When it exceeds the above, the transparency may be lowered and the quality of the container may be lowered.

  A molded article can be obtained by heat-molding the thermoplastic resin composition sheet of the present invention. The heating and molding method is not particularly limited, and general methods such as vacuum molding and hot plate molding can be used. The molding temperature is determined in accordance with the thermoplastic resin composition to be used. If the molding temperature is too low, the difference from the residual heat temperature will be large, which may result in rapid cooling and poor heat resistance. If the molding temperature is too high, the transparency may be lowered, and it may become brittle or may be easily warped when it is cooled after molding.

  The moldability in the present invention is obtained by molding a cup from the sheet of the present invention by vacuum molding using a thermoforming machine, observing the obtained molded product for transparency and shapeability, and evaluating both of them collectively did.

  The heat resistance in the present invention is obtained by forming a cup from the sheet of the present invention by vacuum forming using a thermoforming machine, and changing the heat treatment before and after 30 seconds of heat treatment with hot water at 98 ° C. The transparency and the deformation of the film were observed, and both were comprehensively evaluated.

  Although the use of the molded article of the present invention is not particularly limited, it is suitable for food containers because of its excellent transparency and heat resistance, and is particularly suitable for microwave oven-compatible food containers that can withstand heating by a microwave oven.

  EXAMPLES The present invention will next be described in more detail by way of Examples and Comparative Examples, which should not be construed as limiting the invention thereto.

[Crystallization rate]
The following operation was performed using a SII differential scanning calorimeter (DSC 6200). 10 mg of the resin composition sample was further heated from room temperature to 40 ° C. higher than the melting point of the resin composition at 40 ° C./min, and held at that temperature for 5 minutes. It was then cooled to -30 ° C at 1.25 ° C / min and the crystallization peak temperature was read. Next, the crystallization peak temperature was similarly read at a cooling temperature of 40 ° C./min. For the two crystallization temperatures obtained, the horizontal axis represents the crystallization temperature (° C.), and the vertical axis represents the cooling rate (° C./min), and the absolute value of the slope was taken as the crystallization rate (min-1). .

[Heated temperature crystallization temperature]
Using a differential scanning calorimeter (DSC 6200) manufactured by SII, 10 mg of the thermoplastic resin composition sheet was heated at a temperature rising rate of 20 ° C./min, and the detected melting endothermic peak temperature was defined as the melting point. Next, 10 mg of the thermoplastic resin composition sheet is further heated from room temperature to a high temperature of 30 ° C. relative to the melting point of the resin at 40 ° C./min, held at that temperature for 5 minutes, and 20 ° C./hour using liquid nitrogen. The crystallization peak temperature was read from a DSC chart obtained by cooling to −30 ° C. in min and then raising the temperature at 20 ° C./min, and this was taken as the temperature rising crystallization temperature.

[Thickness]
It measured by the method of JIS-Z-1702 conformity.

[Plane orientation]
Three sample points were taken in the width direction from the roll sample. About the sample according to JIS K 7142-1996 5.1 (Method A), using a sodium D line as a light source, the refractive index (Nx) in the film longitudinal direction, the refractive index in the width direction (Ny), the refraction in the thickness direction The rate (Nz) was measured, and the plane orientation coefficient (ΔP) was calculated by the following equation. In addition, the average value of the obtained surface orientation coefficient was made into the surface orientation coefficient.
ΔP = (Nx + Ny) / 2-Nz

[Haze]
The sample was measured at three different places using a haze meter (manufactured by Nippon Denshoku Co., Ltd., NDH 2000) by a method according to JIS-K-7136: 2000, and the average value was taken as the haze.

[Haze rise by heating for 10 minutes at elevated crystallization temperature]
The sample was heat treated for 10 minutes in air of elevated temperature crystallization temperature as measured by the method described above and then allowed to cool at ambient temperature. The haze of the sample after cooling was measured by the above-mentioned method, and the difference from the haze before the heat treatment was calculated.

[Moldability]
Using a thermoforming machine, vacuum forming was performed at a forming pressure of 0.5 MPa and at a mold temperature at the time of forming shown in Table 1 to obtain a cup from a sheet. The obtained molded product was evaluated for transparency and shapeability, and the both were integrated to determine the evaluation point in 6 steps of 5 to 0. The transparency was evaluated by visual observation as to how much the transparency changed from the sheet at the bottom of the molded article. The evaluation of formability was evaluated by visual observation with respect to the three parts of the bottom, the body and the mouth edge, with respect to the followability to the mold and the presence or absence of breakage.
Evaluation points Evaluation of transparency Evaluation of shapeability 5 No reduction to slight reduction Good 4 No reduction to slight reduction There is a part where transcription deficiency is observed in one site 3 no reduction to slight degradation in two sites There is a part that has been recognized 2 There is no reduction-a slight reduction There is a part where a transcription deficiency is observed at 3 sites 1 A significant reduction It is shaped without breaking (a transcription deficiency does not matter)
0 Unreliable Not shaped or broken

[Haze of molded products]
Samples were taken from three different places at the bottom of a molded product (cup) obtained in the same manner as in the above-mentioned moldability test, the haze of each sample was measured, and the average value was taken as the haze of the molded product. The haze of each sample was measured using a haze meter (NDH 2000, manufactured by Nippon Denshoku Co., Ltd.) according to JIS-K-7105.

[Degree of crystallinity]
A sample was taken from the bottom of a molded article (cup) obtained in the same manner as in the section of the moldability test above, and the density of the sample was measured. The resin component is a mixture of completely amorphous and completely amorphous, and its density is as described later, and the density of the sample is a value obtained by dividing the sum of the masses of the respective components constituting the sample by the sum of the volumes of the respective components. The degree of crystallization (weight ratio) of each resin was estimated based on the assumption that In addition, the density measurement of the sample was performed according to the method (density gradient tube method) based on JISK-7112-1980. Moreover, the density of each component single-piece used the following value (unit: g / cm <3>); polyethylene terephthalate resin: completely amorphous 1.34, completely crystal 1.46. Polyethylene terephthalate resin: completely amorphous 1.28, completely crystalline 1.40. Polypropylene resin: completely amorphous 0.86, completely crystalline 0.95. Nylon 6 resin: completely amorphous 1.11, completely crystalline 1.23. MXD nylon resin: 1.21. Sorbitol derivative master batch (manufactured by Riken Vitamin Co., Ltd., trade name "Rikemaster PN-10R") 0.3 parts, petroleum resin (made by Idemitsu Kosan Co., Ltd., trade name "P-140") 10 parts, petroleum resin (Idemitsu A mixture of 6 parts of Kosan Co., Ltd., trade name "P-125" and 3 parts of polystyrene-poly (ethylene / propylene) block-polystyrene copolymer (Kuraray Co., Ltd., trade name "Septon 2004"): 0. 95. Organically Modified Magnesium Aluminum Silicate Plate (Cloisite 10A from Southern Clay Products): 1.93.

[Boiling resistance]
The molded product (cup) obtained in the section of the moldability test was subjected to a heat treatment of immersion in hot water of 98 ° C. for 30 seconds and subsequently cooling in air at ordinary temperature for 5 minutes. The change in state before and after heat treatment was evaluated by visual observation for the transparency of the entire molded product and the deformation of the form, and the two were combined to determine the evaluation point in five steps of 5 to 1. In the moldability test, no boil resistance evaluation was performed for those having an evaluation point of 0.
Evaluation points Evaluation of deformation Evaluation of deformation of the form 5 No reduction No deformation 4 No reduction Slight deformation 3 Slight reduction 2 Slight deformation 2 Slight reduction Slight deformation 1 Unrecognized large deformation

Example 1
A polypropylene resin (Sumitomo Chemical FS 2011 DG3) was supplied to a single screw extruder. After melt extrusion at 250 ° C. and passing through a filtration filter, it was passed through a 12-element static mixer so as to have a theoretical layer number of 4096 and multilayered, and then extruded into a sheet shape with a T-die. It was cast on a 25 ° C. cooling roll to obtain a 250 μm thick sheet. The details are shown in Table 1.

( Comparative Example 8 )
A sheet was produced in the same manner as in Example 1 except that a 16-element static mixer was used instead of the 12-element static mixer in Example 1, to obtain a 500-μm-thick sheet with 65536 theoretical layers. The details are shown in Table 1.

(Example 3)
A polypropylene resin (Sumitomo Chemical FLX 80E4) was supplied to a single screw extruder. After melt extrusion at 250 ° C. and passing through a filtration filter, the mixture was passed through an 8-element static mixer to form a multilayer, and then extruded into a sheet with a T-die. It was cast on a cooling roll at 25 ° C. to obtain a sheet having a thickness of 100 μm and 256 theoretical layers. The details are shown in Table 1.

(Comparative Examples 1 and 2)
A polypropylene resin (Sumitomo Chemical FS 2011 DG3) was supplied to a single screw extruder. The mixture was melt extruded at 250 ° C., passed through a filter, and then extruded into a sheet with a T-die. It was cast on a cooling roll at 25 ° C. to obtain a 250 μm thick single-layer sheet. The details are shown in Table 1.

(Comparative example 3)
A Toyobo polypropylene film (P216, 50 μm) was used. The details are shown in Table 1.

(Comparative example 4)
Polypropylene resin (FS2011 DG3 manufactured by Sumitomo Chemical Co., Ltd.) 80.7 parts, sorbitol derivative master batch (manufactured by Riken Vitamin Co., Ltd., trade name "Rikemaster PN-10R") 0.3 parts, petroleum resin (made by Idemitsu Kosan Co., Ltd., trade name) 10 parts of “P-140”, 6 parts of petroleum resin (made by Idemitsu Kosan Co., Ltd., trade name “P-125”), polystyrene-poly (ethylene / propylene) block-polystyrene copolymer (made by Kuraray, products Three parts of the name "Septon 2004") were fed to a single screw extruder. After melt extrusion at 250 ° C and passing through a filter,
The sheet was extruded with a T-die. It was cast on a 25 ° C. cooling roll to obtain a 300 μm thick single layer sheet. The details are shown in Table 1.

(Comparative example 5)
Polypropylene resin (FS2011 DG3 manufactured by Sumitomo Chemical Co., Ltd.) 80.7 parts, sorbitol derivative master batch (manufactured by Riken Vitamin Co., Ltd., trade name "Rikemaster PN-10R") 0.3 parts, petroleum resin (made by Idemitsu Kosan Co., Ltd., trade name) 10 parts of “P-140”, 6 parts of petroleum resin (made by Idemitsu Kosan Co., Ltd., trade name “P-125”), polystyrene-poly (ethylene / propylene) block-polystyrene copolymer (made by Kuraray, products Three parts of the name "Septon 2004") were fed to a single screw extruder. After melt extrusion at 250 ° C. and passing through a filtration filter, the mixture was passed through a 12-element static mixer to form a multilayer, and then extruded into a sheet with a T-die. It was cast on a cooling roll at 25 ° C. to obtain a sheet with a thickness of 300 μm and 4096 theoretical layers. The details are shown in Table 1.

  Comparative Examples 1 and 2 use the same polypropylene resin as in Example 1 and Example 2 as a raw material, but have a theoretical layer thickness of 0.5 μm or less and do not have a multilayer laminate structure. It is. In Comparative Example 1 in which the molding temperature was 170 ° C., a molded article showing good boiling resistance could be obtained, but the haze increased and the transparency was significantly reduced. On the other hand, in Comparative Example 2 in which the molding temperature was 120 ° C., it was possible to obtain a molded product having relatively high transparency, but the low degree of crystallization of the molded product significantly reduced the boiling resistance, and the moldability It was also inferior.

  Comparative Example 3 is a commercially available polypropylene film. When the molding temperature was set to 170 ° C. at which the film was softened, the moldability was inferior and the degree of crystallinity was not increased.

  Comparative Example 4 and Comparative Example 5 are cases where other components are added to the polypropylene resin used in Example 1 and Example 2 to increase the crystallization rate outside the scope of the present invention. The comparative example 4 is a single layer sheet which does not have a multilayer laminated structure whose theoretical layer thickness is 0.5 micrometer or less. In Comparative Example 4, molding was inferior when molding at 120 ° C. to maintain transparency. Even when multilayered as in Comparative Example 5, the formability was not improved, and the haze was also equivalent to the haze at 170 ° C. of Example 2.

(Example 4)
What added 5 weight% of organically modified magnesium aluminum silicate plates (Cloisite 10A made by Southern Clay Products) to polyethylene terephthalate resin (PET, Toyobo RE 530) was supplied to a single screw extruder. After melting at 285 ° C, after passing through a filtration filter, the multi-layer feed block (ED is divided and laminated 12 times)
After passing through a multi-layer (product I) to make a multilayer, it was extruded into a sheet shape with a T-die. It was cast on a cooling roll at 25 ° C. to obtain a sheet with a thickness of 300 μm and 4096 theoretical layers. Details are shown in Table 2.

(Comparative example 6)
Polyethylene terephthalate resin (PET, Toyobo RE 530) was supplied to a single screw extruder. After melting at 285 ° C., after passing through a filter, it was extruded into a sheet shape with a T-die. It was cast on a cooling roll at 25 ° C., pressed by a touch roll and quenched to obtain a sheet 500 μm in thickness. The film was stretched twice in length and twice in width at 100 ° C. using a batch-type simultaneous biaxial stretching machine, and then thermally fixed at 200 ° C. to obtain a sheet with a thickness of 100 μm. Details are shown in Table 2.

(Comparative example 7)
A Toyobo polyester film (E5100, 50 μm) was used. Details are shown in Table 2.

  The comparative example 6 is a single layer sheet which does not have a multilayer laminated structure whose theoretical layer thickness is 0.5 micrometer or less. In Comparative Example 6, when forming at 200 ° C. in order to obtain heat resistance, the container was deformed at the time of forming, and the formability was poor.

  Comparative Example 7 is the case of a commercially available polyethylene terephthalate film. When molding was performed at 200 ° C. at which the film is softened, the container was deformed at the time of molding, and the moldability was poor.

(Example 5)
Polybutylene terephthalate resin (NV5020 manufactured by Mitsubishi Engineering Plastics) was supplied to a single screw extruder. After melt extrusion at 240 ° C. and passing through a filtration filter, a multilayer feed block (Nordson EDI Multiplier) with division and lamination times of 10 was passed through to make a multilayer, and then extruded into a sheet shape with a T-die. It was cast on a cooling roll at 25 ° C. to obtain a 250 μm thick sheet having 1024 theoretical layers. Details are shown in Table 2.

(Example 6)
Nylon 6 resin (Toyobo Co., Ltd. T800) was fed to a single screw extruder. After melt extrusion at 270 ° C., and passing through a filter, it was passed through a 10-element static mixer to form a multilayer, and then extruded into a sheet with a T-die. It was cast on a cooling roll at 25 ° C. to obtain a 250 μm thick sheet having 1024 theoretical layers. Details are shown in Table 2.

(Example 7)
A mixture of a polypropylene resin (Sumitomo Chemical FS 2011 DG3) and a polypropylene resin (Sumitomo Chemical FLX 80E4) at a weight ratio of 10/90 was used as the resin composition A, and a polypropylene resin (FS 2011 DG3 manufactured by Sumitomo Chemical) was used as the resin composition B. The resin composition A and the resin composition B were each separately fed to a single screw extruder, melted at 250 ° C., and passed through a filtration filter. Thereafter, they were combined so that the ratio (weight ratio) of resin composition A / resin composition B = 50/50, and then passed through a 12-element static mixer to be multilayered, and then extruded into a sheet shape with a T-die . It was cast on a cooling roll at 25 ° C. to obtain a sheet 250 μm thick and having 4096 theoretical layers. Details are shown in Table 3.

( Comparative Example 9 )
What added 5% of organically modified magnesium aluminum silicate plate (Closite 10A made by Southern Clay Products) to polyethylene terephthalate resin (PET, RE 530 manufactured by Toyobo Co., Ltd.) as resin composition A, polyethylene terephthalate resin (PET, Toyobo RE 530) was used. The resin composition A and the resin composition B were separately fed to a single screw extruder, melted at 285 ° C., and passed through a filter. Then, it laminated | stacked by the feed block so that it might become the ratio (weight ratio) of resin composition A / resin composition B = 40/60. After that, a multi-layer feed block (EDI multiplier) of which the number of divisions / stacking was 12 was passed to make a multi-layer, and then extruded into a sheet shape by a T-die. It was cast on a cooling roll at 25 ° C. to obtain a sheet with a thickness of 300 μm and 4096 theoretical layers. Details are shown in Table 3.

( Comparative Example 10 )
As the resin composition A, an MXD nylon resin (T600, manufactured by Toyobo Co., Ltd.) was used, and as the resin composition B, a polyethylene terephthalate resin (PET, RE530, manufactured by Toyobo Co., Ltd.) was used. The resin composition A and the resin composition B were separately fed to a single screw extruder, melted at 285 ° C., and passed through a filter. Then, it laminated | stacked by the feed block so that it might become the ratio (weight ratio) of resin composition A / resin composition B = 70/30. After that, a multi-layer feed block (EDI multiplier) of which the number of divisions / stacking was 12 was passed to make a multi-layer, and then extruded into a sheet shape by a T-die. It was cast on a cooling roll at 25 ° C. to obtain a sheet with a thickness of 300 μm and 4096 theoretical layers. Details are shown in Table 3.

  According to the present invention, a transparent resin sheet, which is a transparent resin sheet capable of producing a molded article having high transparency and excellent heat resistance even after heat molding, is formed into a film by general-purpose casting equipment It becomes possible. Moreover, the molded article obtained by heat-molding the thermoplastic resin composition sheet of this invention is excellent in heat resistance and transparency, for example, can be widely used for the food container etc. which can be heated with a microwave oven.

Claims (5)

  At least one resin composition selected from the group consisting of a polypropylene resin, a polybutylene terephthalate resin, a polyethylene terephthalate resin, a nylon 6 resin, and a nylon 66, the crystallization rate of which is 0.9 min-1 or more and 3.0 min-1 or less A, the sheet thickness is 10 to 500 μm, the theoretical layer thickness obtained by dividing the sheet thickness by the theoretical number of layers is 0.05 μm to 0.5 μm, and the plane orientation coefficient ΔP is 0 to 0.01 Thermoplastic resin composition sheet.   It is composed of a polypropylene resin composition A having a crystallization rate of 0.9 min-1 to 3.0 min-1 and a polypropylene resin composition B having a crystallization rate equal to or less than the crystallization rate of the polypropylene resin composition A, and the sheet thickness A thermoplastic resin composition sheet having a thickness of 0.05 to 0.5 μm and a plane orientation coefficient ΔP of 0 to 0.01; .   The thermoplastic resin composition according to claim 1 or 2, wherein the haze is 0.1 to 20%, and the rise in the haze (unit:%) when heated for 10 minutes at a temperature rising crystallization temperature is 10 points or less. Object sheet.   The molded article obtained by heat-molding the thermoplastic resin composition sheet in any one of Claims 1-3.   The food container obtained by heat-molding the thermoplastic resin composition sheet in any one of Claims 1-3.