JP6733753B2 - Thermoplastic resin sheet and molded product obtained by heat molding the same - Google Patents

Description

The present invention relates to a thermoplastic resin sheet. More specifically, the present invention relates to a resin sheet that can be used at high temperatures and is suitable for producing a highly transparent heat-molded article, and a method for producing the resin sheet. The most typical application of the molded article of the present invention is a food container that can be heated by a microwave oven, but is not limited thereto and can be widely used for various containers that require heat resistance and transparency.

Resin sheets are used as various protective films to be stuck to the surface of sealants and display materials, and also used as sheet materials for heat molding. Among the sheet materials for heat molding, those with excellent transparency are required for applications such as various food containers, decorations, and vending machine displays. Conventionally, there is a decrease in transparency due to crystallization. Sheet materials such as polystyrene (PSt), which are of no concern, have been used. However, these materials have only a heat resistance of about 100° C., and when used at high temperatures such as microwave oven cooking, the heat resistance including mechanical properties such as the lid material is limited and the performance is insufficient. And there was no material that was well balanced in terms of price.

For food container applications compatible with microwave ovens, molded products of crystalline materials with good heat resistance are used, and polypropylene resin (PP) is particularly preferably used from the viewpoint of high crystallinity and heat resistance. .. For PP, a film forming method for forming a sheet or a film is properly used depending on the application. For example, a stretched PP film is used as various packaging materials that do not require moldability, while an unstretched sheet is a heat-molding sheet material. Is widely used as From future trends in lifestyle, it is expected that the amount of containers that can be used in microwave ovens that can be used at high temperatures will increase, but PP has a large amount of crystals formed during heat molding, resulting in poor transparency. Therefore, there is a problem that it is not preferable when the container is required to have high transparency in terms of designability.

Some techniques are disclosed with respect to these subjects. In Patent Document 1, by blending PP with a petroleum resin and a nucleating agent and forming a sheet using a quenching process during casting, it is possible to suppress whitening during molding and obtain a molded body having high transparency. A technique for manufacturing a transparent sheet is disclosed. However, in such a conventional technique, when the mold temperature during molding is lowered in order to maintain the transparency of the molded product, the heat resistance of the molded product decreases with the decrease in crystallinity, and the heat resistance of the molded product is reduced. There is a problem that the transparency of the molded product is lowered when the temperature of the mold during molding is increased to increase the transparency, and it is difficult to achieve both moldability and heat resistance. Further, there is also a problem that it is difficult to manufacture a sheet using a general-purpose film forming equipment because a special film forming equipment such as a belt process is required for rapid cooling during casting.

Further, there is known a technique for producing a PP sheet having excellent flexibility and a relatively good balance between moldability and heat resistance by inflation film formation (see Patent Document 2). However, such a conventional technique has a problem in that it is insufficient in terms of transparency of the sheet and is not suitable for forming a thick sheet suitable for heat molding.

On the other hand, for a polyester heat-molding sheet, a technique is known in which a PET resin containing a nucleating agent for promoting crystallization called CPET is sheet-molded and heat-molded (see Patent Document 3). However, in such a conventional technique, although heat resistance is significantly improved as compared with a molded product obtained by heat-molding a normal PET sheet, spherulites develop and become opaque, and impact resistance at low temperature is greatly reduced, Further, there has been a problem that if the mold temperature during molding is lowered in order to improve these problems, the moldability and heat resistance are lowered.

Therefore, there is a known technique that the heat resistance is improved by stretching the sheet at a low magnification to cause oriented crystallization within a range where the formability does not decrease, and the decrease in transparency can be suppressed by refining generated crystals. (See Patent Document 4). However, such a conventional technique has a limitation in terms of equipment for manufacturing a sheet, such as equipment for suppressing shrinkage at the time of heat molding is required, and stretching equipment becomes large when a thick sheet is manufactured. There was a point.

JP2012-139826A Re-table 99/007752 JP, 2000-355091, A JP, 2011-245643, A

The present invention has been made against the background of the problems of the related art. That is, an object of the present invention is a transparent resin sheet that can be formed into a film by a general-purpose casting facility, and it is possible to produce a molded product having high transparency and excellent heat resistance even after heat molding. It is to provide a resin sheet.

The inventors of the present invention have completed the present invention as a result of earnest studies for achieving the above object.
That is, the present invention is
<1> At least one selected from the group consisting of polypropylene resin having a crystallization rate of 0.9 min-1 or more and 3.0 min-1 or less, polybutylene terephthalate resin, polyethylene terephthalate resin, nylon 6 resin, nylon 66. The resin composition A is used, 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 or more and 0.5 μm or less, and the plane orientation coefficient ΔP is 0 to 0. The thermoplastic resin composition sheet of No. 01.
<2> A polypropylene resin composition A having a crystallization rate of 0.9 min-1 or more and 3.0 min-1 or less and a polypropylene resin composition B having a crystallization rate of the crystallization rate of the polypropylene resin composition A or less. A thermoplastic resin having 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 to 0.5 μm, and a surface orientation coefficient ΔP of 0 to 0.01. Composition sheet.
<3> The haze is 0.1 to 20%, and the increase in the haze (unit: %) when heated for 10 minutes at the elevated temperature crystallization temperature is 10 points or less. <1> or” <2> The thermoplastic resin composition sheet.
<4> A molded product obtained by heat-molding the thermoplastic resin composition sheet according to any one of <1> to <3>.
<5> A food container obtained by heat-molding the thermoplastic resin composition sheet according to any one of <1> to <3>.

In the extruded sheet extruded from the die and molded through the step of dividing the molten resin composition into 200 layers or more in the thickness direction of the film and laminating the layers, the layers between the layers are laminated. It was found that the interface has an effect of functioning as a crystallization starting point. Also, since the interface crystallizes before other parts, the vicinity of the interface becomes a wall and the crystal growth is divided by the wall, and further, the crystal cannot grow beyond the thickness of the interface due to the division. I found that. It was also found that increasing the number of interfaces increases the number of crystallization initiation points and reduces the distance between the interfaces. As a result, they have found that the size of spherulites can be suppressed to be small even after the sheet is heat-formed at a high temperature such as vacuum forming, and a highly transparent sheet can be obtained.

According to the present invention, there is provided a transparent resin sheet which can be formed into a film by a general-purpose casting facility, and which is capable of producing a molded product having high transparency and excellent heat resistance even after being heat-molded. can do.

The present invention has at least the following step (1), step (2) and step (3), the sheet thickness is 10 to 1000 μm, and the theoretical layer thickness obtained by dividing the sheet thickness by the number of theoretical layers is 0.5 μm or less. A method for producing a 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): A laminated fluid A2 composed of the molten fluid A1 and having a laminated number of 200 or more is formed.
Step (3): The laminated fluid A2 is discharged from a die and brought into contact with a cooling roll to be solidified. In addition, the present invention has a sheet thickness of 10 to 1000 μm, which has at least 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. A method for producing a thermoplastic resin composition sheet having a thickness of 0.5 μm or less.
Step (1A): 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 (1B): A thermoplastic resin composition B having a crystallization rate equal to or lower than the crystallization rate of the thermoplastic resin composition A is melted to form a molten fluid B.
Step (2): A laminated fluid AB2 having a laminated number of 200 or more and formed of the molten fluid A1 and the molten fluid B1 is formed.
Step (3): The laminated fluid AB2 is discharged from a die and brought into contact with a cooling roll to be solidified.

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 are collectively referred to as the thermoplastic composition in the present invention.

Examples of thermoplastic resins that can be used in the thermoplastic resin composition of the present invention include polypropylene, polyethylene, polybutylene terephthalate, nylon 6 and the like. Specific examples thereof include Noblene manufactured by Sumitomo Chemical Co., polypropylene polypropylene manufactured by Prime Polymer, polypropylene manufactured by Sun Allomer, and the like. Examples of polyethylene include Novatec LL/HD manufactured by Nippon Polyethylene and Hi-Zex/Neo-Zex manufactured by Prime Polymer. Also, as polybutylene terephthalate, Mitsubishi Engineering Plastics Nova Duran, Wintech Polymer Duranex, Toray Toraycon, Nippon GE Plastics Barox, etc., Polyethylene terephthalate made by Toyobo, Nippon Unipet Unipet, etc., and also sold by each company. Examples of the recycled PET resin include: In addition, nylon 6 as Toyobo grammide, Ube Industries UBE nylon, etc., nylon 66 as Asahi Kasei Leona, Toray Amylan, Ube Industries UBE nylon 66, BASF Ultramit, copolyamides and other polyamides Arkema Rilsan , Daicel-Evonik Vestamid/Daiamide, Sumitomo Chemical Sumika Super LCP as liquid crystalline polyester, Polyplastics Vectra, Polyphenylene sulfide DIC PPS resin, Polyplastics Fortron, etc. Polycarbonate Teijin Chemical Panlite , Mitsubishi Engineering Plastics Iupilon, Sumika Stylon Polycarbonate Gulliver, and polyphenylene ether.
These resins may be used alone or in combination of two or more.

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

Crystallization nucleating agents include phosphoric acid ester salt-based, sorbitol-based, and carboxylate-based based on their structural classification, and specifically include ADEKA ADEKA STAB NA series, Shin Nippon Rika Gelol, and RIKAFAST. .. Examples of the amorphous polymer include copolyester and polycarbonate. Specific examples of the copolyester include polyphthalic acid other than terephthalic acid such as isophthalic acid, orthophthalic acid, succinic acid, sebacic acid and cyclohexyldicarboxylic acid, diethylene glycol, neopentyl glycol, 3-methyl-1,5-pentane. The thing which copolymerized the diol, the bisphenol A alkylene oxide adduct, cyclohexane dimethylol, etc. can be used. Specific examples of the polycarbonate include Gulliver manufactured by Sumika Stylon, SD Polycarbonate, Iupilon manufactured by Mitsubishi Engineering Plastics, Novalex, Panlite manufactured by Teijin Chemicals, and Teflon manufactured by Idemitsu Kagaku. The content of the crystallization nucleating agent is preferably in the range of 1 to 10% by weight based on the whole thermoplastic resin composition. Further, the content of the amorphous polymer is preferably 050% by weight, and more preferably 0 to 45% by weight, based on the whole thermoplastic resin composition. If it exceeds 50 parts by weight, crystallinity is lowered and heat resistance is lowered, which is not preferable.

As other components that can be used in the thermoplastic resin composition of the present invention, various additives can be mentioned. Examples of the additives include a plasticizer, a release agent, a flame retardant, a lubricant, a coloring agent (dye or pigment), an antistatic agent, an antifogging agent, an adhesion promoter and the like. These additives can be appropriately 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 further preferably 0.05. It is preferable that the addition amount of these is appropriately adjusted according to the purpose. The upper limit of the additive amount (% by weight) is preferably 10, more preferably 8, and even more preferably 5. If it exceeds the above range, the physical properties of the resin are largely deteriorated, and the appearance may be deteriorated due to bleeding out or the like.

Other components that can be used in the thermoplastic resin composition according to the present invention may be used by directly entering the extruder together with the resin, or may be mixed with the resin in advance and used as a masterbatch. .. Examples of master batches containing a crystallization nucleating agent include Clear Master manufactured by Dainichi Seika.

As the thermoplastic resin in the present invention, one having a specific crystallization rate range is used. The crystallization rate referred to here is as described in P. of New Polymer Experimental Science 8 edited by The Polymer Society of Japan. 117 as reference 121. Y. P. Khanna: Polym. Eng. & Sci. , 24, 1615 (1990) were used. An example of a specific measurement procedure is separately shown 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 and the transparency of the obtained sheet may be lowered, and the moldability may be poor. Further, 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.

The lower limit of the melt viscosity (MFR) of the thermoplastic resin composition of the present invention is not particularly limited, but is preferably 0.01 g/10 minutes, more preferably 0.05 g/10 minutes, and further preferably 0. It is 10 g/10 minutes. If it is less than the above range, the melt viscosity may be too high and the productivity during molding may be reduced. The upper limit of the melt viscosity (MFR) of the resin composition is preferably 50, more preferably 45, and further preferably 40. If it exceeds the above range, the pressure during discharge may be too low, and it may be difficult to perform casting with a uniform thickness. The MFR in the present invention is a value measured by the method described in JIS K7210:2014.

The lower limit of the melting point (°C) of the thermoplastic resin composition of the present invention is preferably 100, more preferably 110, and further preferably 120. If it is less than the above range, the heat resistance may be poor and the applications may be limited. The upper limit of the melting point (° C.) of the resin composition is preferably 350, more preferably 340, still more preferably 330. If it exceeds the above, the effect of heat resistance may be saturated, and it is necessary to raise the process temperature during the production of the sheet and the production of the heat-formed product of the sheet, and the production equipment corresponding thereto is required. .. As the melting point of the thermoplastic resin composition in the present invention, the 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. To do.

(Method for 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. A step (1) of melting a thermoplastic resin in the present invention to form a molten fluid (or steps (1A) and (1B)), and a stacking number of 200 or more comprising the molten fluid formed in the step (1) The method further includes at least a step (2) of forming a laminated fluid and a 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. 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 changing step, etc. may be inserted between the step (1) and the step (2). Further, a temperature changing step, a charge adding step, etc. may be inserted between the step (2) and the step (3). However, there must be no step between the step (2) and the step (3) to destroy the laminated structure formed in the step (2).

In the step (1) (or the step (1A) and the step (1B)), the method of forming the molten fluid by melting the thermoplastic resin in the present invention is not particularly limited, but a preferable method includes a single-screw extruder and A method of heating and melting using a twin-screw extruder can be mentioned.

The method for forming the layered 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. Preferably. When forming a laminated fluid composed of the resin composition A and the resin composition B, the resin compositions formed in the step (1A) and the step (1B) are merged to form a resin composition having two layers first. Then, it is preferable to pass the molten resin composition through any one or more of a static mixer, a multi-layer feed block and a multi-layer manifold installed in the melt line.

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

The theoretical number of layers in the step (2) needs to be 200 or more. The lower limit of the theoretical number of layers is preferably 500, more preferably 1000. If the theoretical number of layers is too small, the effect of accelerating crystallization is insufficient, or the distance between layer interfaces becomes long and the crystal size becomes too large, so that the effect of the present invention tends to be unobtainable. In addition, the transparency after molding may decrease near the 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 further preferably 7,000. Even if the theoretical number of layers is extremely increased, the effect is saturated, and a problem may occur in terms of production efficiency.

When the lamination in the step (2) is performed with a static mixer, the theoretical number of laminations can be adjusted by selecting the number of elements of the static mixer. The static mixer is generally known as a static mixer (line mixer) having no drive unit, and the fluid that has entered the mixer is sequentially stirred and mixed by the elements. However, when the high-viscosity fluid is passed through the static mixer, the high-viscosity fluid is divided and laminated, and a laminated fluid is formed. Each time one element of the static mixer is passed, the high-viscosity fluid is divided into two and then merged and laminated. Therefore, when the high-viscosity fluid is passed through the static mixer with the number of elements n, the laminated fluid with the theoretical number of layers N=2n is formed. Further, it is also possible to use a laminating fluid as the high-viscosity fluid supplied to the static mixer. When the number of layers of the high-viscosity fluid supplied to the static mixer is m, the theoretical number of layers N of the layered fluid is N=m×2n.

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

When the stacking in the step (2) is performed by a multilayer feed block, the theoretical number of stacks can be adjusted by selecting the number of divisions/stacking of the multilayer feed block. Multiple multi-layer feed blocks can be installed in series. Further, the high-viscosity fluid itself supplied to the multi-layer feed block can be used as a laminated fluid. For example, when the number of laminated high-viscosity fluids supplied to the multilayer feed block is p, the number of divided/laminated multilayer feed blocks is q, and the number of installed multilayer feed blocks is r, the number N of laminated fluids is N=p. Xqr.

In step (3), the lamination fluid is discharged from the die and brought into contact with a cooling roll to be solidified.

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, more preferably the melting point +10. The upper limit of the die temperature (°C) is preferably melting point +60, more preferably melting point +50.

The lower limit of the cooling roll temperature (° C.) is preferably 5, more preferably 10, and further 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 further preferably 20. If the above value is exceeded, it may be necessary to take measures such as wrinkles during cooling in the subsequent equipment.

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

The lower limit of the theoretical layer thickness (μm) in the present invention is preferably 0.001, more preferably 0.01, and further preferably 0.05. If it is less than the above range, the effect is saturated, which may cause a problem in production efficiency. The upper limit of the theoretical layer thickness (μm) is preferably 0.45, more preferably 0.3, even more preferably 0.2, and even more preferably 0.1. If it exceeds the above range, the size of the spherulites becomes large after molding, and the transparency decreases.

The lower limit of the sheet thickness (μm) in the present invention is preferably 10, more preferably 100, and further preferably 200. If it is less than the above range, 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 further preferably 500. If it exceeds the above range, the thickness may be too large and the moldability may be deteriorated.

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

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

When layers with high crystallization speed and layers with low crystallization speed are alternately stacked, spherulites start to grow at the interface between the layer with high crystallization speed and the layer with low crystallization speed as a starting point. Therefore, a crystal wall is formed at the interface and the crystal growth is divided. Further, a layer having a slow crystallization rate is also crystallized with a delay, but the crystallization is divided by the crystal wall.

The ratio of the theoretical layer thickness of the layer made of the thermoplastic resin composition A and the layer made 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 formula.
Theoretical thickness of layer composed of thermoplastic resin composition A=[sheet thickness×[volume discharge rate of thermoplastic resin composition A/(volume discharge rate of thermoplastic resin composition A+volume discharge of thermoplastic resin composition B Speed)]]/(theoretical number of layers/2)
Theoretical thickness of layer composed of thermoplastic resin composition B=[sheet thickness×[volume discharge rate of thermoplastic resin composition B/(volume discharge rate of thermoplastic resin composition A+volume discharge of thermoplastic resin composition B Speed)]]/(theoretical number of layers/2)

The lower limit of the sheet thickness (μm) of the present invention is preferably 10, more preferably 100, and further preferably 200. If it is less than the above range, 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 further preferably 500. If it exceeds the above range, the thickness may be too large and the moldability may be deteriorated.

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 further preferably 0.08. If it exceeds the above range, the malleability at the time of drawing may be lowered, and the formability may be lowered. If the molecular chains are oriented parallel to the film surface, the transparency tends to be improved, but this may hinder the molding of the container. The plane orientation coefficient is related to the degree of stretching during film production, and tends to increase with stretching. At the time of producing the thermoplastic resin composition sheet of the present invention, it is necessary to take care not to excessively stretch it.

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

The lower limit of the crystallinity (%) of the sheet of the present invention is preferably 20, more preferably 25, and further preferably 30. If it is less than the above, deformation due to progress of crystallization over time or heat resistance may decrease.
The upper limit of the crystallinity (%) of the sheet of the present invention is preferably 80, more preferably 75. If it exceeds the above, the effect will be 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 the elevated 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. If the haze rise exceeds 10 points, the transparency after molding into a container or the like is low, and the object of the present invention is not met. In order to reduce the amount of haze increase, it is necessary that the size of the crystals generated in the crystallization process is small, and it is effective to reduce the theoretical layer thickness and to add a crystal nucleating agent.

In addition, the temperature rising crystallization temperature in the present invention is obtained by analyzing a thermoplastic resin sheet using a DSC apparatus, holding the resin sheet at a high temperature of 30° C. for 5 minutes, and then rapidly cooling and solidifying at a cooling rate of 20° C./min. Then, it is a crystallization peak temperature in a DSC chart obtained by heating at a temperature rising 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 apparatus is used.

The lower limit of haze (%) after forming the sheet of the present invention into a container is preferably 1, more preferably 1.5, and further preferably 1.5. If it is less than the above, scratches may be more noticeable.

The upper limit of haze (%) after forming the sheet of the present invention into a container is preferably 20, more preferably 18, and particularly preferably 15. If it exceeds the above range, the transparency may be deteriorated and the quality as a container may be deteriorated.

A molded product can be obtained by heat-molding the thermoplastic resin composition sheet of the present invention. The heat 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 according to the thermoplastic resin composition used. If the molding temperature is too low, the difference from the residual heat temperature becomes large, so that the temperature is rapidly cooled and the heat resistance may deteriorate. If the molding temperature is too high, the transparency may decrease, and the composition may become brittle or warp during cooling after molding.

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

Regarding the heat resistance in the present invention, the molded product obtained by molding a cup from the sheet of the present invention by vacuum molding using a thermoforming machine, shows the change in the molded product before and after the heat treatment for 30 seconds with hot water at 98°C. The transparency and deformation were observed, and both were evaluated comprehensively.

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

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Crystallization rate]
The following operation was performed using the differential scanning calorimeter (DSC6200) manufactured by SII. 10 mg of the resin composition sample was heated at 40° C./min from room temperature to a temperature higher than the melting point of the resin composition by 30° C. and held at that temperature for 5 minutes. Next, it cooled at 1.25 degreeC/min to -30 degreeC, and read the crystallization peak temperature. Then, the cooling temperature was set to 40° C./min and the crystallization peak temperature was read in the same manner. For the two obtained crystallization temperatures, the horizontal axis is the crystallization temperature (°C) and the vertical axis is the cooling rate (°C/min), and the absolute value of the slope is the crystallization rate (min-1). ..

[Raised temperature crystallization temperature]
Using a differential scanning calorimeter (DSC6200) manufactured by SII, 10 mg of the thermoplastic resin composition sheet was heated at a heating rate of 20° C./minute, and the detected melting endothermic peak temperature was taken as the melting point. Next, 10 mg of the thermoplastic resin composition sheet was heated at 40° C./min from room temperature to a temperature higher than the melting point of the resin by 30° C., held at that temperature for 5 minutes, and heated at 20° C./min using liquid nitrogen. The crystallization peak temperature was read from the DSC chart obtained by cooling to −30° C. for min and then raising the temperature at 20° C./min, and set it as the temperature rising crystallization temperature.

[Thickness]
It was measured by the method according to JIS-Z-1702.

[Face orientation]
Three point samples were taken from the roll sample in the width direction. Regarding the sample, according to JIS K 7142-1996 5.1 (method A), the refractive index in the longitudinal direction of the film (Nx), the refractive index in the width direction (Ny), and the refractive index in the thickness direction were measured by an Abbe refractometer using sodium D line as a light source. The rate (Nz) was measured, and the plane orientation coefficient (ΔP) was calculated by the following formula. The average value of the obtained surface orientation coefficients was defined as the surface orientation coefficient.
ΔP=(Nx+Ny)/2−Nz

[Haze]
The sample was measured by a method according to JIS-K-7136:2000 using a haze meter (NDH2000 manufactured by Nippon Denshoku Co., Ltd.) at three different points, 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 the air having the elevated crystallization temperature measured by the method described above, and then allowed to cool at room temperature. The haze of the sample after allowed to cool was measured by the method described above, and the difference from the haze before the heat treatment was calculated.

[Moldability]
Using a thermoforming machine, vacuum molding was performed at a molding pressure of 0.5 MPa and the mold temperature during molding shown in Table 1 to obtain a cup from the sheet. The obtained molded product was evaluated for transparency and shapeability, and the two were comprehensively evaluated at 6 points from 5 to 0. The transparency was evaluated by visually observing how much the transparency of the bottom of the molded product changed from the sheet. The shapeability was evaluated by visually observing the goodness of the ability to follow the mold and the presence or absence of breakage in the three parts of the bottom part, the body part, and the rim part.
Evaluation point Transparency evaluation Shape-forming property evaluation 5 No decrease-slight decrease Satisfactory 4 No decrease-slight decrease 1 There is a portion where transcription deficiency is observed at 1 site 3 No decrease-slight reduction 2 Deficiency of transcription at 2 sites There is a recognized part 2 No decrease to slightly decreased 3 There is a part where transcription deficiency is recognized at 1 site 1 Significant decrease Shaped without breakage (transcription deficiency does not matter)
0 Undescribed or broken

[Haze of molded products]
Samples were taken from three different locations on the bottom of the 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 used as the haze of the molded product. The haze of each sample was measured by a method according to JIS-K-7105 using a haze meter (NDH2000 manufactured by Nippon Denshoku Co., Ltd.).

[Crystallinity]
A sample was taken from the bottom of the molded product (cup) obtained in the same manner as in the above-mentioned moldability test, 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 below, and the density of the sample is a value obtained by dividing the total sum of the masses of the respective components constituting the sample by the total volume of the respective components. The crystallinity (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 JIS K-7112-1980. The following values were used for the density of each component alone (unit: g/cm3); 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 and completely crystalline 1.23. MXD nylon resin: 1.21. Sorbitol derivative masterbatch (Riken Vitamin Co., Ltd., trade name "Rikemaster PN-10R") 0.3 parts, petroleum resin (Idemitsu Kosan Co., Ltd., trade name "P-140") 10 parts, petroleum resin (Idemitsu Mixture of 6 parts of trade name "P-125" manufactured by Kosan Co., Ltd. and 3 parts of polystyrene-poly(ethylene/propylene) block-polystyrene copolymer (manufactured by Kuraray Co., Ltd., trade name "Septon 2004"): 0. 95. Organically modified magnesium aluminum silicate plate (Cloisite 10A from Southern Clay Products): 1.93.

[Boil resistance]
The molded product (cup) obtained in the item of the moldability test was immersed in hot water of 98° C. for 30 seconds, and subsequently subjected to a heat treatment of allowing it to cool in air at room temperature for 5 minutes. The change in the state before and after the heat treatment was evaluated by visually observing the transparency of the entire molded product and the deformation of the form, and the evaluation points were evaluated on the basis of 5 to 5 in total. Boil resistance was not evaluated for those having a rating of 0 in the moldability test.
Evaluation point Transparency evaluation Deformation evaluation of form 5 No decrease No deformation 4 No decrease Slight deformation is observed 3 Slight decrease Slight deformation is observed 2 Significant decrease Slight deformation is observed 1 Unquestionably large deformation is observed

(Example 1)
Polypropylene resin (FS2011DG3 manufactured by Sumitomo Chemical) was supplied to a single-screw extruder. The mixture was melt extruded at 250° C., passed through a filtration filter, passed through a 12-element static mixer so as to have a theoretical layer number of 4096 layers, and multilayered, and then extruded into a sheet by a T die. It was cast on a cooling roll at 25° C. to obtain a sheet having a thickness of 250 μm. Details are shown in Table 1.

( Comparative Example 8 )
A sheet was manufactured in the same manner as in Example 1 except that a 16-element static mixer was used in place of the 12-element static mixer in Example 1, to obtain a sheet having a thickness of 500 μm and a theoretical layer number of 65536 layers. Details are shown in Table 1.

(Example 3)
A polypropylene resin (FLX80E4 manufactured by Sumitomo Chemical Co., Ltd.) was supplied to a single-screw extruder. The mixture was melt extruded at 250° C., passed through a filtration filter, 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 a theoretical number of layers of 256 layers. Details are shown in Table 1.

(Comparative Examples 1 and 2)
Polypropylene resin (FS2011DG3 manufactured by Sumitomo Chemical) was supplied to a single-screw extruder. The mixture was melt extruded at 250° C., passed through a filtration filter, and then extruded into a sheet with a T die. It was cast on a cooling roll at 25° C. to obtain a single layer sheet having a thickness of 250 μm. Details are shown in Table 1.

(Comparative example 3)
A polypropylene film (P2161, 50 μm) manufactured by Toyobo was used. Details are shown in Table 1.

(Comparative Example 4)
80.7 parts of polypropylene resin (FS2011DG3 manufactured by Sumitomo Chemical), 0.3 parts of sorbitol derivative masterbatch (manufactured by Riken Vitamin Co., Ltd., product name "Rikemaster PN-10R"), petroleum resin (manufactured by Idemitsu Kosan Co., Ltd., product name) "P-140") 10 parts, petroleum resin (manufactured by Idemitsu Kosan Co., Ltd., trade name "P-125") 6 parts, polystyrene-poly(ethylene/propylene) block-polystyrene copolymer (manufactured by Kuraray Co., Ltd., product 3 parts (named "Septon 2004") were fed to a single-screw extruder. After melt extruding at 250°C and passing through a filtration filter,
It was extruded into a sheet with a T-die. It was cast on a cooling roll at 25° C. to obtain a single-layer sheet having a thickness of 300 μm. Details are shown in Table 1.

(Comparative example 5)
80.7 parts of polypropylene resin (FS2011DG3 manufactured by Sumitomo Chemical), 0.3 parts of sorbitol derivative masterbatch (manufactured by Riken Vitamin Co., Ltd., product name "Rikemaster PN-10R"), petroleum resin (manufactured by Idemitsu Kosan Co., Ltd., product name) "P-140") 10 parts, petroleum resin (manufactured by Idemitsu Kosan Co., Ltd., trade name "P-125") 6 parts, polystyrene-poly(ethylene/propylene) block-polystyrene copolymer (manufactured by Kuraray Co., Ltd., product 3 parts (named "Septon 2004") were fed to a single-screw extruder. The mixture was melt extruded at 250° C., passed through a filtration filter, 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 having a thickness of 300 μm and a theoretical layer number of 4096 layers. Details are shown in Table 1.

Comparative Example 1 and Comparative Example 2 use the same polypropylene resin as Example 1 and Example 2 as a raw material, but do not have a multilayer laminated structure with a theoretical layer thickness of 0.5 μm or less, a single-layer sheet. Is. In Comparative Example 1 in which the molding temperature was 170° C., a molded product having good boil resistance could be obtained, but the haze increased and the transparency remarkably decreased. On the other hand, in Comparative Example 2 in which the molding temperature was 120° C., a molded product having a relatively high transparency could be obtained, but since the crystallinity of the molded product was low, the boiling resistance was remarkably lowered, and the moldability was improved. 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 softened, the moldability was poor and the crystallinity did not increase.

Comparative Examples 4 and 5 are cases in which other components were added to the polypropylene resins used in Examples 1 and 2 to increase the crystallization rate outside the range of the present invention. Comparative Example 4 is a single-layer sheet having a theoretical layer thickness of 0.5 μm or less and having no multilayer laminated structure. In Comparative Example 4, the molding was inferior when molded at 120° C. in order to maintain the transparency. The moldability was not improved even if it was multilayered as in Comparative Example 5, and the haze was the same as the haze at 170° C. molding of Example 2.

(Example 4)
A polyethylene terephthalate resin (PET, RE530 manufactured by Toyobo) containing 5% by weight of an organically modified magnesium aluminum silicate plate (Cloisite 10A manufactured by Southern Clay Products) was supplied to a uniaxial extruder. After melting at 285°C and passing through a filtration filter, a multilayer feed block (ED
(Multiplier made by I) 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 300 μm and a theoretical layer number of 4096 layers. Details are shown in Table 2.

(Comparative example 6)
A polyethylene terephthalate resin (PET, Toyobo RE530) was supplied to a single-screw extruder. After melting at 285° C., the mixture was passed through a filtration filter and then extruded into a sheet with a T die. It was cast on a cooling roll of 25° C., pressed with a touch roll and rapidly cooled to obtain a sheet having a thickness of 500 μm. Using a batch type simultaneous biaxial stretching machine, this was stretched twice at 100° C. in the lengthwise direction and twice at the horizontal direction and then heat-set at 200° C. to obtain a sheet having a thickness of 100 μm. Details are shown in Table 2.

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

Comparative Example 6 is a single-layer sheet having a theoretical layer thickness of 0.5 μm or less and having no multilayer laminated structure. In Comparative Example 6, when molding was performed at 200° C. to obtain heat resistance, the container was deformed during molding, resulting in poor moldability.

Comparative Example 7 is a commercially available polyethylene terephthalate film. When molding was carried out at a molding temperature of 200° C. at which the film softens, the container was deformed during molding and the moldability was poor.

(Example 5)
Polybutylene terephthalate resin (NV5020 manufactured by Mitsubishi Engineering Plastics) was supplied to a single-screw extruder. The mixture was melt extruded at 240° C., passed through a filtration filter, passed through a multi-layer feed block (multiplier made by Nordson EDI) having 10 divisions/laminations, and then extruded into a sheet with a T die. The sheet was cast on a cooling roll at 25° C. to obtain a sheet having a thickness of 250 μm and a theoretical layer number of 1024 layers. Details are shown in Table 2.

(Example 6)
Nylon 6 resin (T800 manufactured by Toyobo) was supplied to the single-screw extruder. The mixture was melt extruded at 270° C., passed through a filtration filter, passed through a 10-element static mixer to form a multilayer, and then extruded into a sheet with a T die. The sheet was cast on a cooling roll at 25° C. to obtain a sheet having a thickness of 250 μm and a theoretical layer number of 1024 layers. Details are shown in Table 2.

(Example 7)
A mixture of polypropylene resin (FS2011DG3 manufactured by Sumitomo Chemical Co., Ltd.) and polypropylene resin (FLX80E4 manufactured by Sumitomo Chemical Co., Ltd.) in a weight ratio of 10/90 was used as resin composition A, and polypropylene resin (FS2011DG3 manufactured by Sumitomo Chemical Co., Ltd.) was used as resin composition B. The resin composition A and the resin composition B were individually supplied to a single-screw extruder, melted at 250° C., and passed through a filtration filter. After that, the resin composition A/the resin composition B was merged at a ratio of 50/50 (weight ratio), passed through a 12-element static mixer to form a multilayer, and then extruded into a sheet by a T die. .. The sheet was cast on a cooling roll at 25° C. to obtain a sheet having a thickness of 250 μm and a theoretical layer number of 4096 layers. Details are shown in Table 3.

( Comparative Example 9 )
Polyethylene terephthalate resin (PET, RE530 manufactured by Toyobo) added with 5% of an organically modified magnesium aluminum silicate plate (Cloisite 10A manufactured by Southern Clay Products) as resin composition A, and polyethylene terephthalate resin (PET, as resin composition B) Toyobo RE530) was used. The resin composition A and the resin composition B were individually supplied to a uniaxial extruder, melted at 285° C., and passed through a filtration filter. Then, the resin composition A/the resin composition B was laminated by a feed block so that the ratio (weight ratio) was 40/60. Then, after passing through a multi-layer feed block (multiplier made by EDI) having 12 times of division and lamination to make a multi-layer, a sheet was extruded by a T-die. It was cast on a cooling roll at 25° C. to obtain a sheet having a thickness of 300 μm and a theoretical layer number of 4096 layers. Details are shown in Table 3.

( Comparative Example 10 )
MXD nylon resin (T600 manufactured by Toyobo) was used as the resin composition A, and polyethylene terephthalate resin (PET, RE530 manufactured by Toyobo) was used as the resin composition B. The resin composition A and the resin composition B were individually supplied to a uniaxial extruder, melted at 285° C., and passed through a filtration filter. Then, the resin composition A/the resin composition B was laminated by a feed block so that the ratio (weight ratio) was 70/30. Then, after passing through a multi-layer feed block (multiplier made by EDI) having 12 times of division and lamination to make a multi-layer, a sheet was extruded by a T-die. It was cast on a cooling roll at 25° C. to obtain a sheet having a thickness of 300 μm and a theoretical layer number of 4096 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 product having high transparency and excellent heat resistance even after being heat-molded, is formed by a general-purpose casting facility. It becomes possible. The molded product obtained by heat-molding the thermoplastic resin composition sheet of the present invention has excellent heat resistance and transparency, and can be widely used for food containers that can be heated by a microwave oven, for example.

Claims (4)

A polypropylene resin composition A having a crystallization rate of 0.9 min −1 or more and 3.0 min −1 or less and a polypropylene resin composition B having a crystallization rate of the polypropylene resin composition A or less, and a 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 or more and 0.5 μm or less, and the plane orientation coefficient ΔP is 0 to 0.01. .. The thermoplastic resin composition sheet according to claim 1, wherein the haze is 0.1 to 20%, and an increase in haze (unit: %) when heated for 10 minutes at a rising crystallization temperature is 10 points or less. .. That obtained by heating molded thermoplastic resin composition sheet according to claim 1 or 2, the manufacturing method of the molded article. That obtained by heating molded thermoplastic resin composition sheet according to claim 1 or 2, the manufacturing method of food containers.