JP2017002229A - Sheet for thermal molding and molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet for thermal molding which can provide a large molded body small in hanging of a sheet, good in size enlargement property to a complex mold and small in thickness deviation and is excellent in heat resistance and chemical resistance.SOLUTION: There is provided a sheet for thermal molding having thickness of 1 mm or more and formed by a polypropylene resin composition containing a polypropylene resin (X) a polypropylene resin composition having MFR of 0.1 to 30 g/10 min., melting tension (MT, unit:g) satisfying log(MT)≥-0.9×log(MFR)+0.7 or log(MT)≥1.15 and having a long chain branched structure of 5 to 100 wt.% and a polypropylene resin (Y) having MFR of 0.1 to 9.5 g/10 min., melting tension (MT, unit:g) satisfying log(MT)<-0.9×log(MFR)+0.7 and log(MT)<1.15 of 95 to 0 wt%.SELECTED DRAWING: None

Description

  The present invention relates to a thermoforming sheet and a molded body, and more particularly relates to a thermoforming sheet and a molded body made of a polypropylene resin composition.

  Sheets for thermoforming are widely formed by thermoforming such as vacuum forming, pressure forming, vacuum pressure forming, etc., from small molded products such as packaging containers such as food containers to large molded products such as structural members such as housing members. It is used. As characteristics required for the packaging container, characteristics such as transparency and gloss, and characteristics such as heat resistance and oil resistance when the contents are cooked in a microwave oven are required. Furthermore, in recent years, interest in environmental problems has increased, and polypropylene resin sheets are preferred over amorphous resin sheets such as polystyrene and ABS, which are excellent in thermoformability. On the other hand, structural members are required to have excellent mechanical properties such as rigidity, strength, and heat resistance, and excellent moldability such as drawdown resistance and spreadability.

  Propylene homopolymers and propylene-α-olefin random copolymers are used as polypropylene-based resins for sheets used in the manufacture of molded products by thermoforming, in terms of moldability, product rigidity, and transparency. It is often done. However, these resins have low melt tension, and cannot be said to have sufficient draw-down resistance in sheet thermoforming, and improvements are required.

  In order to improve the drawdown resistance, a resin composition containing a polypropylene resin having a long-chain branched structure has been proposed (see, for example, Patent Document 1). However, this composition does not have sufficient draw-down resistance when thermoforming a thick and large molded product.

  Furthermore, since many large molded products have complicated shapes, the sheet is also required to have good extensibility in thermoforming. Polypropylene resin used for conventional thermoforming cannot be said to have sufficient spreadability, and even if it can be shaped into a complex shape, it is obtained by non-uniform extension. The body has a large thickness and tends to buckle and break. Therefore, it has been difficult to satisfy the higher reliability required for the structural member. For such a structural member, a thermoformed body made of an amorphous resin such as ABS or polystyrene is often used (see, for example, Patent Document 2). However, such an amorphous resin is inferior in heat resistance and chemical resistance, and has the disadvantage that various restrictions are imposed on the use environment of the structural member product.

JP 2002-294209 A JP 2000-117903 A

  The object of the present invention is to form a complex metal sheet with a small sheet sag, even in the case of producing a large molded body in a thermoforming sheet used for thermoforming such as vacuum forming, pressure forming, vacuum pressure forming, etc. An object of the present invention is to provide a thermoforming sheet that has a good moldability to a mold, can provide a molded product with small uneven thickness, and is excellent in heat resistance and chemical resistance.

The thermoforming sheet of the present invention that achieves the above object is a thermoforming sheet having a thickness of 1 mm or more formed of a polypropylene resin composition, wherein the polypropylene resin composition has a long-chain branched structure. (X) 5 to 100% by weight and polypropylene resin (Y) 95 to 0% by weight, wherein the polypropylene resin (X) has the following characteristics (Xi) and (X-ii), (Y) has the following characteristics (Yi) and (Y-ii).
Characteristic (X-i): Melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kg is 0.1 to 30 g / 10 minutes Characteristic (X-ii): Melt tension (MT) (unit: g) Characteristic (Yi) satisfying log (MT) ≧ −0.9 × log (MFR) +0.7 or log (MT) ≧ 1.15: Melt flow measured at 230 ° C. and 2.16 kg load Rate (MFR) is 0.1 to 9.5 g / 10 min Characteristic (Y-ii): Melt tension (MT) (unit: g) is log (MT) <− 0.9 × log (MFR) +0.7 And log (MT) <1.15

  Since the sheet for thermoforming of the present invention is made of a polypropylene resin composition containing a polypropylene resin (X) having a long-chain branched structure and optionally a polypropylene resin (Y), it has excellent heat resistance and chemical resistance, In the case of producing a large molded article by molding, the sheet sag is small and the formability is excellent. Further, the obtained molded body has an effect that the uneven thickness is small and the buckling strength is excellent.

It is preferable that the polypropylene resin (X) having the long-chain branched structure has a characteristic (X-iii): mm fraction of three propylene units chain by ¹³ C-NMR of 95% or more.

  The molded body obtained by thermoforming the sheet for thermoforming of the present invention is excellent in heat resistance and chemical resistance, has a small uneven thickness, and is excellent in buckling strength.

  The thermoforming sheet of the present invention is a thermoforming sheet having a thickness of 1 mm or more formed from a polypropylene resin composition. The thermoforming sheet is an original fabric used for thermoforming such as vacuum forming, pressure forming, vacuum pressure forming, etc., and can be used for both large and small shaped products. Examples of the large molded article include door trims, automobile members such as instrument panels and roof carriers, building material interior panels, wash basin panels, large transport trays, and the like. Examples of small molded products include food containers such as trays, dishes, and cups.

  The thermoforming sheet may be either a single layer sheet or a multilayer sheet as long as it includes a layer having a thickness of 1 mm or more formed from a polypropylene resin composition. A single layer sheet is a sheet | seat which consists only of a layer containing a specific polypropylene resin composition. The multilayer sheet is a laminated sheet in which a layer containing a specific polypropylene resin composition and at least one layer selected from a gas barrier resin layer, an adhesive resin layer, a recycled resin layer, a candle resin layer, and the like are stacked.

  In the thermoforming sheet of the present invention, the thickness of the layer containing the polypropylene resin composition is 1 mm or more, preferably more than 2 mm, more preferably more than 3 mm, and still more preferably more than 3.1 mm. The thermoformed sheet of the present invention preferably has a thickness of 100 mm or less, more preferably less than 50 mm, and even more preferably less than 10 mm. By setting the thickness of the layer containing the polypropylene resin composition to 1 mm or more, uneven thickness can be reduced.

  The thermoforming sheet of the present invention is obtained by, for example, extruding a polypropylene resin composition through a single screw extruder or a twin screw extruder into a sheet shape from, for example, a coat solder die, and then (for example, cooling water or oil is circulated therein. It can be obtained by cooling and solidifying by pressing the metal roll surface with an air knife, air chamber, hard rubber roll, steel belt, metal roll or the like. It is also possible to cool and solidify both sides of the thermoforming sheet with a steel belt. Among such methods for cooling a thermoforming sheet, a method using a metal roll and / or a steel belt on both sides of the sheet can obtain a sheet surface with less surface irregularities, that is, a sheet having excellent transparency. This is the most preferable method.

  Further, the thermoforming sheet of the present invention can be formed into a multilayer sheet using an extruder equipped with a plurality of dies and using a feed block and a multi-manifold.

  The polypropylene resin composition constituting the thermoforming sheet of the present invention contains 5 to 100% by weight of polypropylene resin (X) having a long-chain branched structure and 95 to 0% by weight of polypropylene resin (Y). Hereinafter, the polypropylene resin composition will be described.

Polypropylene resin (X)
In the present invention, the polypropylene resin (X) has the following characteristics (X-i) and (X-ii).
Characteristic (X-i): Melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kg is 0.1 to 30 g / 10 minutes Characteristic (X-ii): Melt tension (MT) (unit: g) Satisfies log (MT) ≧ −0.9 × log (MFR) +0.7 or log (MT) ≧ 1.15. The polypropylene resin (X) may have the following characteristics (X-iii): .
Characteristic (X-iii): The mm fraction of three propylene units by ¹³ C-NMR is 95% or more. Hereinafter, characteristics (Xi) to (X-iii) and other characteristics will be described in order.

(X-i): The melt flow rate (MFR) measured at 230 ° C. and a 2.16 kg load of the polypropylene resin (X) is 0.1 to 30 g / 10 min.
The melt flow rate (MFR) of the polypropylene resin (X) is a value measured at 230 ° C. and a 2.16 kg load. The MFR of the polypropylene resin (X) is 0.1 to 30 g / 10 minutes, preferably 0.2 to 20 g / 10 minutes, more preferably 0.5 to 9.5 g / 10 minutes. When the MFR is 0.1 g / 10 min or more, when the sheet is extruded, the load on the extruder is suppressed, and the productivity is improved. On the other hand, if it exceeds 30 g / 10 minutes, sufficient melt tension cannot be obtained, and the molded body may sag under its own weight during extrusion molding or thermoforming, which may make molding difficult.

  The MFR of the polypropylene resin (X) can be adjusted by controlling the hydrogen concentration during polymerization. MFR is a value measured according to JIS K7210.

(X-ii): The melt tension (MT) (unit: g) of the polypropylene resin (X) is:
The melt tension (MT) of the polypropylene resin (X) satisfying log (MT) ≧ −0.9 × log (MFR) +0.7 or log (MT) ≧ 1.15 is log (MT) ≧ −0. 9 × log (MFR) +0.7, or log (MT) ≧ 1.15, preferably log (MT) ≧ −0.9 × log (MFR) +0.9, or log (MT) ≧ 1 .15 is satisfied. More preferably, log (MT) ≧ −0.9 × log (MFR) +1.1 or log (MT) ≧ 1.15 is satisfied.

  When the MFR and melt tension (MT) of the polypropylene resin (X) satisfy the above characteristic (X-ii), the drawdown resistance is excellent. There is no upper limit on the melt tension (MT), but if it is too large, the extensibility will decrease, the moldability to the mold will deteriorate at the time of thermoforming, and in extreme cases the molding will be torn. Since defects may occur, log (MT) ≦ 1.48 (MT ≦ 30.2) is preferable.

As a method for controlling the melt tension (MT) of the polypropylene resin (X), although depending on the type of the catalyst, the chain transfer agent hydrogen is changed to 1.0 × 10 ^{−6 to} 0 in the molar ratio of hydrogen / propylene during the polymerization. It is possible to obtain a desired melt tension (MT) by adjusting within a range of .2.

  Further, the relationship between the MFR and the melt tension (MT) of the polypropylene resin (X) can be adjusted by, for example, the type of catalyst. For example, according to JP 2009-275207 A, a propylene polymer obtained by using a catalyst containing two specific types of transition metal compounds has a high melt tension, and the relationship between MFR and melt tension described above is obtained. It can be used as a filling polypropylene resin.

  The melt tension (MT) of the polypropylene resin (X) is a diameter of 9 ° C. heated to 230 ° C. using a capillograph (for example, a capillograph manufactured by Toyo Seiki Co., Ltd. is used in the examples of the present specification). The resin is put into a 6 mm cylinder, and the molten resin is extruded from an orifice having a diameter of 2.0 mm and a length of 40 mm at an indentation speed of 20 mm / min. The tension detected by the pulley when the extruded resin was taken out at a speed of 4.0 m / min was measured, and this was the melt tension (MT).

(X-iii): The polypropylene resin (X) has a mm fraction of three propylene units by ¹³ C-NMR, preferably 95% or more.
The polypropylene resin (X) preferably has high stereoregularity. The high degree of stereoregularity can be evaluated by the mm fraction of three propylene units by ¹³ C-NMR. The mm fraction of the three propylene units obtained by ¹³ C-NMR of the polypropylene resin (X) is preferably 95% or more, more preferably 96% or more, and still more preferably 97% or more.

  The mm fraction is the ratio of propylene unit 3 chain in which the direction of methyl branching in each propylene unit is the same in any propylene unit chain consisting of head-to-tail bonds in the polymer chain, and the upper limit is 100%. is there. This mm fraction is a value indicating that the steric structure of the methyl group in the polypropylene molecular chain is controlled isotactically, and the higher the value, the higher the isotactic control. When the mm fraction is 95% or more, the drawdown resistance during thermoforming and the buckling strength of the molded body are improved.

In addition, the measuring method of mm fraction of the propylene unit 3 chain | strand by ¹³ C-NMR of polypropylene resin (X) is as follows.
A sample of 375 mg was completely dissolved in 2.5 ml of deuterated 1,1,2,2, -tetrachloroethane in an NMR sample tube (10φ) and then subjected to proton complete decoupling at 125 ° C. under the following conditions. taking measurement. The chemical shift sets the central peak of the three peaks of deuterated 1,1,2,2-tetrachloroethane to 74.2 ppm. The chemical shift of other carbon peaks is based on this.
Flip angle: 90 degrees Pulse interval: 10 seconds Resonance frequency: 100 MHz or more Integration frequency: 10,000 times or more Observation range: -20 ppm to 179 ppm
Number of data points: 32768

The mm fraction is determined using the ¹³ C-NMR spectrum measured under the above conditions. The spectrum is assigned with reference to Macromolecules, (1975), Vol. 8, 687 and Polymer, Vol. 30, p. 1350 (1989). Note that a more specific method for determining the mm fraction is described in detail in paragraphs [0053] to [0065] of Japanese Patent Laid-Open No. 2009-275207, and the present invention is performed according to this method. .

(X-iv) The molecular weight distribution Mw / Mn determined from the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) of the polypropylene resin (X) is preferably 3 to 10 It is.
The polypropylene resin (X) preferably has a molecular weight distribution Mw / Mn by gel permeation chromatography (GPC) of 3 to 10, more preferably 3.5 to 8, and still more preferably 4.1 to 6. When the Mw / Mn of the polypropylene resin (X) is in the above range, the molding processability is particularly excellent when the sheet is extruded.

(Xv) The molecular weight distribution Mz / Mw determined from the Z average molecular weight (Mz) and Mw measured by GPC of the polypropylene resin (X) is preferably 2.5 to 10.
Furthermore, as for polypropylene resin (X), molecular weight distribution Mz / Mw by gel permeation chromatography (GPC) becomes like this. Preferably it is 2.5-10, More preferably, it is 2.8-8, More preferably, it is 3-6. When the Mz / Mw of the polypropylene resin (X) is in the above range, the molding processability is particularly excellent when the sheet is extruded.

  In this specification, the definitions of Mn, Mw, and Mz are described in “Basics of Polymer Chemistry” (edited by Polymer Society, Tokyo Kagaku Dojin, 1978), and Mn, Mw, and Mz are molecular weight distributions by GPC. It can be calculated from the curve.

In the present invention, the GPC measurement method is as follows.
Apparatus: GPC manufactured by Waters (ALC / GPC 150C)
Detector: MIRAN 1A IR detector manufactured by FOXBORO (measurement wavelength: 3.42 μm)
Column: AD806M / S (3 pieces) manufactured by Showa Denko KK
-Mobile phase solvent: orthodichlorobenzene (ODCB)
・ Measurement temperature: 140 ℃
・ Flow rate: 1.0 ml / min
・ Injection volume: 0.2ml
Sample preparation: Prepare a 1 mg / mL solution using ODCB (containing 0.5 mg / mL BHT) and dissolve it at 140 ° C. for about 1 hour.

Conversion from the retention capacity obtained by the GPC measurement to the molecular weight is performed using a calibration curve (calibration curve) of standard polystyrene prepared in advance. As standard polystyrene, the following brands made by Tosoh Corporation are used.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000

A calibration curve is created by injecting 0.2 mL of a solution dissolved in ODCB (containing 0.5 mg / mL BHT) so that each standard polystyrene is 0.5 mg / mL. The calibration curve uses a cubic equation obtained by approximation by the least square method.
In addition, the following numerical value is used for the viscosity formula [η] = K × M ^α used for conversion to molecular weight.
PS: K = 1.38 × 10 ⁻⁴ , α = 0.7
PP: K = 1.03 × 10 ⁻⁴ , α = 0.78

  Polypropylene resin (X) has a long-chain branched structure. As a direct index that the polypropylene resin (X) has a long-chain branched structure, a branching index g ′ can be mentioned. The branching index g ′ is determined by the ratio of the intrinsic viscosity [η] lin of the linear polymer having the same molecular weight as the intrinsic viscosity [η] br of the polymer having a long chain branched structure, that is, [η] br / [η] lin. Given that g ′ <1, it can be said that it has a long-chain branched structure.

  The definition of the branching index g ′ is described in, for example, “Developments in Polymer Characterization-4” (JV Dawkins ed. Applied Science Publishers, 1983), and is an index known to those skilled in the art.

  A suitable range of the branching index g ′ can be obtained as a function of the absolute molecular weight Mabs by using, for example, a light scatterometer as described below and a GPC equipped with a viscometer in the detector.

  The polypropylene resin (X) preferably has a branching index g ′ of 0.30 or more and less than 1.00, more preferably 0.55 or more and 0.98 when the absolute molecular weight Mabs determined by light scattering is 1,000,000. Hereinafter, it is more preferably 0.75 or more and 0.96 or less, and most preferably 0.78 or more and 0.95 or less.

The calculation method of the branching index g ′ is as follows.
An Alliance GPCV2000 manufactured by Waters is used as a GPC device equipped with a differential refractometer (RI) and a viscosity detector (Viscometer). As the light scattering detector, a DAWN-E manufactured by Wyatt Technology, a multi-angle laser light scattering detector (MALLS) is used. The detectors are connected in the order of MALLS, RI, and Viscometer. The mobile phase solvent is 1,2,4-trichlorobenzene (added with an antioxidant Irganox 1076 manufactured by BASF Japan Ltd. at a concentration of 0.5 mg / mL).

  The flow rate of the mobile phase solvent is 1 mL / min, and two GMHHR-H (S) HT manufactured by Tosoh Corporation are connected and used as the column. The temperature of the column, sample injection section, and each detector is 140 ° C. The sample concentration is 1 mg / mL and the injection volume (sample loop volume) is 0.2175 mL.

  In order to obtain the absolute molecular weight (Mabs) obtained from MALLS, the mean square inertia radius (Rg), and the intrinsic viscosity ([η]) obtained from Viscometer, data processing software ASTRA (version 4.73.04) attached to MALLS is used. The calculation is performed with reference to the following documents.

References:
1. “Developments in Polymer Characterization-4” (JV Dawkins ed. Applied Science Publishers, 1983. Chapter 1.)
2. Polymer, 45, 6495-6505 (2004).
3. Macromolecules, 33, 2424-2436 (2000)
4). Macromolecules, 33, 6945-6952 (2000)

  The branching index g ′ is a ratio of the intrinsic viscosity ([η] br) obtained by measuring a sample with the above Viscometer and the intrinsic viscosity ([η] lin) obtained separately by measuring a linear polymer ([[ η] br / [η] lin).

  Here, as a linear polymer for obtaining [η] lin, a commercially available homopolypropylene (Novatech (registered trademark) PP grade name: FY6 manufactured by Nippon Polypro Co., Ltd.) is used. The fact that the logarithm of [η] lin of a linear polymer has a linear relationship with the logarithm of molecular weight is known as the Mark-Houwink-Sakurada equation, so [η] lin is appropriately set on the low molecular weight side or the high molecular weight side. Extrapolation can be used to obtain numerical values.

  The polypropylene resin (X) having a long-chain branched structure can be obtained, for example, by a so-called macromer copolymerization method in which a propylene macromer having a terminal double bond is polymerized from a propylene monomer, and the propylene macromer and the propylene monomer are copolymerized. . However, the production method of the polypropylene resin (X) is not limited to the macromer copolymerization method.

  Polypropylene resin (X) is a propylene homopolymer obtained by homopolymerizing propylene by single-stage polymerization or two-stage or more multistage polymerization, and propylene and α-olefin are co-polymerized by single-stage polymerization or two-stage or more multistage polymerization. A propylene / α-olefin random copolymer obtained by polymerization, a polymerization step in which propylene is homopolymerized by single-stage polymerization or multistage polymerization of two or more stages to obtain a propylene homopolymer, and propylene and α-olefin are single-stage Any of propylene / α-olefin block copolymers obtained by polymerization or polymerization comprising two or more stages of copolymerization to obtain a propylene / α-olefin random copolymer by copolymerization However, a propylene homopolymer and a propylene / α-olefin random copolymer are preferable.

  The α-olefin is preferably ethylene or an α-olefin having 4 to 18 carbon atoms. Specifically, ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4,4-dimethylpentene- 1 etc. can be mentioned. Moreover, as an alpha olefin, 1 type or the combination of 2 or more types may be sufficient.

Polypropylene resin (Y)
In the present invention, the polypropylene resin (Y) has the following characteristics (Yi) and (Y-ii).
Characteristic (Y-i): Melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kg is 0.1 to 9.5 g / 10 minutes Characteristic (Y-ii): Melt tension (MT) (unit: g) satisfies log (MT) <− 0.9 × log (MFR) +0.7 and log (MT) <1.15. Characteristics (Yi) to (Y-ii) and other characteristics Will be described in turn.

(Yi): The melt flow rate (MFR) measured at 230 ° C. and a load of 2.16 kg of the polypropylene resin (Y) is 0.1 to 9.5 g / 10 minutes.
The melt flow rate (MFR) (230 ° C., 2.16 kg load) of the polypropylene resin (Y) is 0.1 to 9.5 g / 10 minutes, preferably 0.1 to 3 g / 10 minutes, more preferably 0.00. It is 2-1.5 g / 10min, More preferably, it is 0.3-0.9g / 10min. When the MFR is 0.1 g / 10 min or more, when the sheet is extruded, the load on the extruder is suppressed, and the productivity is improved. Further, it is preferable that the MFR is 9.5 g / 10 min or less because the melt tension of the sheet can be kept high, and the molded body does not sag under its own weight during extrusion molding or thermoforming.

  The MFR of the polypropylene resin (Y) can be adjusted by controlling the hydrogen concentration during polymerization. MFR is a value measured according to JIS K7210.

(Y-ii): The melt tension (MT) (unit: g) of the polypropylene resin (Y) is
The melt tension (MT) of the polypropylene resin (Y) satisfying log (MT) <− 0.9 × log (MFR) +0.7 and log (MT) <1.15 is log (MT) <− 0. It is preferable to satisfy 9 × log (MFR) +0.6 and log (MT) <1.04 (MT <11). More preferably, log (MT) <− 0.9 × log (MFR) +0.5 and log (MT) <0.85 (MT <7) may be satisfied.

  When the MFR and melt tension (MT) of the polypropylene resin (Y) satisfy the above characteristics (Y-ii), the spreadability is excellent. The lower limit of the melt tension is not specified, but if it is too small, the drawdown resistance is lowered, and the temperature range that can be molded at the time of thermoforming may be narrowed. Therefore, log (MT)> 0.48 ( MT> 3).

(Y-iii): The molecular weight distribution Mw / Mn measured by GPC of the polypropylene resin (Y) is preferably 3.5 to 10.
The polypropylene resin (Y) preferably has a molecular weight distribution Mw / Mn (where Mw is a weight average molecular weight and Mn is a number average molecular weight) by gel permeation chromatography (GPC), preferably 3.5 to 10, more preferably 3 .7-8, more preferably 4-6. When the Mw / Mn of the polypropylene resin (Y) is in the above range, the molding processability is particularly excellent when the sheet is extruded. The molecular weight distribution Mw / Mn of the polypropylene resin (Y) can be obtained in the same manner as the molecular weight distribution Mw / Mn of the polypropylene resin (X).

  The polypropylene resin (Y) preferably does not have a long chain branched structure. The branching index g ′ of the polypropylene resin (Y) is preferably 1. The branching index g ′ of the polypropylene resin (Y) can be obtained in the same manner as the branching index g ′ of the polypropylene resin (X).

  Polypropylene resin (Y) is a propylene homopolymer obtained by homopolymerizing propylene by single-stage polymerization or two-stage or more multistage polymerization, and propylene and α-olefin are co-polymerized by single-stage polymerization or two-stage or more multistage polymerization. A propylene / α-olefin random copolymer obtained by polymerization, a polymerization step in which propylene is homopolymerized by single-stage polymerization or multistage polymerization of two or more stages to obtain a propylene homopolymer, and propylene and α-olefin are single-stage Any of propylene / α-olefin block copolymers obtained by polymerization or polymerization comprising two or more stages of copolymerization to obtain a propylene / α-olefin random copolymer by copolymerization However, a propylene homopolymer and a propylene / α-olefin random copolymer are preferable.

  The α-olefin is preferably ethylene or an α-olefin having 4 to 18 carbon atoms. Specifically, ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4,4-dimethylpentene- 1 etc. can be mentioned. Moreover, as an alpha olefin, 1 type or the combination of 2 or more types may be sufficient.

  The polypropylene resin (Y) is preferably polymerized with a Ziegler-Natta catalyst. Here, the Ziegler-Natta catalyst is preferably a catalyst comprising a solid component essential for titanium, magnesium, halogen, organoaluminum, and an electron donor used as necessary.

Polypropylene resin composition The polypropylene resin composition constituting the thermoformed sheet of the present invention is 5 to 100% by weight of polypropylene resin (X), 0 to 95% by weight of polypropylene resin (Y), preferably polypropylene resin (X). 10 to 100% by weight, polypropylene resin (Y) 0 to 90% by weight, more preferably polypropylene resin (X) 20 to 100% by weight and polypropylene resin (Y) 0 to 80% by weight. Here, the total amount of the polypropylene resin (X) and the polypropylene resin (Y) is 100% by weight. If the ratio of the polypropylene resin (X) to the total of the polypropylene resin (X) and the polypropylene resin (Y) is 5% by weight or more, it is preferable that the molded body does not sag under its own weight during extrusion molding or thermoforming. .

  In the polypropylene resin composition constituting the thermoformed sheet of the present invention, when the melt flow rate of the polypropylene resin (X) is MFRx and the melt flow rate of the polypropylene resin (Y) is MFRy, these ratios MFRx / MFRy are preferable. Preferably satisfies 30> MFRx / MFRy> 1. More preferably, 15> MFRx / MFRy> 1.5 is satisfied. By setting the ratio MFRx / MFRy within the above range, it is possible to obtain a molded body with a smaller uneven thickness. In addition, MFRx and MFRy shall be measured by 230 degreeC and a 2.16kg load as above-mentioned.

(Optional component)
In the polypropylene resin composition, if necessary, any component may be added for the purpose of imparting other effects, for example, further improving the effects of the present invention within a range not significantly impairing the effects of the present invention. Can be added.

  Specifically, colorants such as pigments, light stabilizers such as hindered amines, UV absorbers such as benzotriazoles, nucleating agents such as sorbitols, antioxidants such as phenols and phosphoruss, nonionics Antistatic agents such as hydrotalcite, antibacterial and antifungal agents such as thiazoles, flame retardants such as halogen compounds, plasticizers, dispersants such as fatty acid metal salts, lubricants such as fatty acid amides, nitrogen Metal deactivators such as compounds, nonionic surfactants, fillers such as talc, polyethylene resins other than the polypropylene resins (X and Y), thermoplastic resins such as polyamide resins and polyester resins, olefins Examples include elastomers (rubber components) such as elastomers and styrene-based elastomers.

  These optional components may be used in combination of two or more, may be added to the propylene resin (X), may be added to the polypropylene resin (Y), etc. In each component, 2 More than one species can be used in combination.

  As the colorant, for example, inorganic or organic pigments are effective for imparting or improving the colored appearance, appearance, texture, commercial value, weather resistance, durability, etc. of the thermoforming sheet according to the present invention. It is.

  Specific examples of inorganic pigments include carbon blacks such as furnace carbon and ketjen carbon; titanium oxide; iron oxide (such as Bengala); chromic acid (such as yellow lead); molybdic acid; selenide sulfide; Organic pigments include poorly soluble azo lakes; soluble azo lakes; insoluble azo chelates; condensable azo chelates; azo pigments such as other azo chelates; phthalocyanine blue; phthalocyanine pigments such as phthalocyanine green; anthraquinones; Perylene; a selenium pigment such as thioindigo; a dye lake; a quinacridone system; a dioxazine system; and an isoindolinone system. Moreover, in order to make a metallic tone or a pearl tone, an aluminum flake; a pearl pigment can be contained. Moreover, dye can also be contained.

  Examples of light stabilizers and ultraviolet absorbers include hindered amine compounds, benzotriazole compounds, benzophenone compounds and salicylate compounds, which are effective for imparting and improving the weather resistance and durability of the thermoforming sheet according to the present invention. And is effective in further improving the weather discoloration resistance.

  Specific examples of the hindered amine compound include a condensate of dimethyl succinate and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine; poly [[6- (1, 1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2 , 2,6,6-tetramethyl-4-piperidyl) imino]]; tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate; tetrakis ( 1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate; bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebake Bis-2,2,6,6-tetramethyl-4-piperidyl sebacate and the like, and examples of the benzotriazole-based compound include 2- (2′-hydroxy-3 ′, 5′-di-t- Butylphenyl) -5-chlorobenzotriazole; 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) -5-chlorobenzotriazole and the like. Hydroxy-4-methoxybenzophenone; 2-hydroxy-4-n-octoxybenzophenone and the like. Examples of the salicylate compounds include 4-t-butylphenyl salicylate; 2,4-di-t-butylphenyl 3 ′, And 5'-di-t-butyl-4'-hydroxybenzoate.

  Here, the method in which the light stabilizer and the ultraviolet absorber are used in combination is preferable because the effect of improving weather resistance, durability, weather discoloration and the like is great.

  As an antioxidant, for example, antioxidants such as phenolic, phosphorus and sulfur are used for imparting and improving the heat forming stability, processing stability, heat aging resistance, etc. of the thermoforming sheet according to the present invention. It is valid.

  Further, as the antistatic agent, for example, a nonionic or cationic antistatic agent is effective for imparting and improving the antistatic property of the thermoforming sheet according to the present invention.

  Examples of the olefin elastomer include ethylene / propylene copolymer elastomer (EPR), ethylene / butene copolymer elastomer (EBR), ethylene / hexene copolymer elastomer (EHR), and ethylene / octene copolymer elastomer (EOR). ) And other ethylene / α-olefin copolymer elastomers; ethylene / propylene / ethylidene norbornene copolymers, ethylene / propylene / butadiene copolymers, ethylene / propylene / isoprene copolymers, etc. Examples thereof include an original copolymer elastomer and a styrene / butadiene / styrene triblock copolymer elastomer (SBS).

  Examples of the styrene elastomer include styrene / isoprene / styrene triblock copolymer elastomer (SIS), styrene-ethylene / butylene copolymer elastomer (SEB), styrene-ethylene / propylene copolymer elastomer (SEP), and styrene. -Ethylene-butylene-styrene copolymer elastomer (SEBS), Styrene-ethylene-butylene-ethylene copolymer elastomer (SEBC), Hydrogenated styrene-butadiene elastomer (HSBR), Styrene-ethylene-propylene-styrene copolymer elastomer (SEPS), styrene-ethylene / ethylene / propylene / styrene copolymer elastomer (SEEPS), styrene / butadiene / butylene / styrene copolymer elastomer (SBBS), part Styrenic elastomers such as hydrogenated styrene-isoprene-styrene copolymer elastomers, partially hydrogenated styrene-isoprene / butadiene-styrene copolymer elastomers, and water such as ethylene-ethylene / butylene-ethylene copolymer elastomers (CEBC) Examples thereof include an additive polymer elastomer.

  It is preferable that the usage-amount of the arbitrary component mentioned above is 100 weight part or less with respect to 100 weight part of total amounts of polypropylene resin (X) and polypropylene resin (Y).

  The polypropylene resin composition can be obtained by mixing the polypropylene resin (X), the polypropylene resin (Y), and optional components to be added as necessary with a dry blend, a Henschel mixer or the like. Furthermore, melt kneading can be performed with a single screw extruder, a twin screw extruder or the like.

  The thermoforming sheet of the present invention is a thermoforming sheet having a thickness of 1 mm or more formed from the above-described polypropylene resin composition. The sheet for thermoforming is obtained by extruding a polypropylene resin composition into a sheet through a single screw extruder or a twin screw extruder.

  The molded body of the present invention can be obtained by molding the thermoforming sheet by a thermoforming method such as vacuum forming, pressure forming, vacuum pressure forming, or plug assist vacuum pressure forming. Examples of the heating method in such thermoforming include indirect heating, hot plate heating, and hot roll heating.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, the scope of the present invention is not limited to these Examples.

The properties of the polypropylene resin (X), the polypropylene resin (Y) and the thermoforming sheet were determined by the following evaluation methods.
1. Evaluation method (1) Melt flow rate (MFR)
MFR of polypropylene resin (X) and polypropylene resin (Y) was measured according to JIS K7210: 1999, Method A, Condition M (230 ° C., 2.16 kg load). The unit is g / 10 minutes.

(2) Melting point (Tm)
The melting point (Tm) of the polypropylene resin (X) was measured using a DSC6200 manufactured by Seiko Instruments Inc. 5 mg of sheet-like sample pieces are packed in an aluminum pan, once heated from room temperature to 200 ° C. at a heating rate of 100 ° C./min, held for 5 minutes, then cooled to 10 ° C./min to 20 ° C., and then The melting point Tm was determined as the maximum melting peak temperature when the temperature was raised to 200 ° C. at 10 ° C./min. The unit is ° C.

(3) Melt tension MT
The melt tension MT of the polypropylene resin (X) and the polypropylene resin (Y) was measured under the following conditions using a Capillograph manufactured by Toyo Seiki Seisakusho, and this was designated as MT.
・ Capillary: Diameter 2.0mm, length 40mm
・ Cylinder diameter: 9.55mm
・ Cylinder extrusion speed: 20 mm / min ・ Pickup speed: 4.0 m / min ・ Temperature: 230 ° C.
When MT is extremely high, the resin may break at a take-up speed of 4.0 m / min. In such a case, the take-up speed is decreased by 0.1 m / min at a maximum and the take-up speed is maximum. The tension at a speed of 1 was designated as MT. The unit is gram.

(4) Molecular weight distributions Mw / Mn and Mz / Mw
It was determined by GPC measurement according to the method described above.

(5) mm fraction The mm fraction of the polypropylene resin (X) is as described above using GSX-400, FT-NMR, manufactured by JEOL Ltd., paragraphs [0053] to [ [0065]. The unit is%.

(6) Drawdown resistance From the polypropylene resin sheet obtained in each Example and each Comparative Example, a test piece having a size of 300 mm × 300 mm was cut out and fixed horizontally to a frame having an inner size of 260 mm × 260 mm. Using a dripping tester manufactured by Misuzu Erie Co., Ltd., led to a heating furnace in a testing machine in which heaters are arranged one above the other and heated at an atmospheric temperature of 200 ° C., and the time-dependent change in the vertical displacement of the sample center from the start of heating. Were sequentially measured with a laser beam.

With heating, the sheet once hangs down (displaces in the minus direction) and then hangs up again after being relieved by stress relaxation (displaced in the plus direction). Assuming that the sheet position (displacement) at the start of heating is A (mm), the position (displacement) at the maximum rebound is B (mm), and the position (displacement) 10 seconds after the maximum rebound is C (mm), The drawdown resistance was evaluated according to the following criteria.
A: B−A ≧ 0 mm and C−B ≧ −5 mm
○: B−A ≧ −5 mm and C−B ≧ −10 mm (except when B−A ≧ 0 mm and C−B ≧ −5 mm)
Δ: B−A ≧ −5 mm and C−B <−10 mm, or B−A <−5 mm and C−B ≧ −10 mm
×: B−A <−5 mm and C−B <−10 mm
Here, B−A ≧ −5 mm means that the sheet is tensioned at the time of container molding, and a beautiful appearance without wrinkles is possible, and that C−B ≧ −10 mm is good. This means that the molding time range for obtaining a molded product is sufficiently wide.

(7) Extensibility From the polypropylene resin sheet obtained in each Example and each Comparative Example, a test piece having a size of 200 mm × 200 mm was cut out and fixed to a circular frame having an inner radius of 80 mm. Using a dripping tester manufactured by Misuzu Erie, lead the heater to the heating furnace in the testing machine where the heaters are arranged up and down, heat it at an atmospheric temperature of 200 ° C, and after 2 seconds from the maximum tension, plug the plug installed on the top of the seat The sheet was lowered by air cylinder pressure at 0.1 m / second, and the sheet was deep drawn. For the resulting cone-shaped molded body having a height of 200 mm, the thickness of the body at 11 reference points provided at 15 mm intervals between the height direction of 25 mm and 175 mm was measured with a micrometer, and the minimum measurement The value was taken as the minimum thickness of the trunk.

(8) Buckling strength (7) For the cone-shaped molded body obtained by the evaluation of spreadability, the sheet raw fabric portion at the top of the molded body is fixed, and a load of 1 kg is applied to the convex portion at the bottom of the molded body, The buckling strength was visually determined according to the following criteria.
○: Buckling is not recognized ×: Buckling is recognized

Example 1
As the polypropylene resin (X), WAYMAX MFX8 (referred to as “X1” in Tables 1, 3 and 4) manufactured by Nippon Polypro Co., Ltd. was used, and this was used as the polypropylene resin composition. The properties of the polypropylene resin X1 were measured by the evaluation method described above and are shown in Table 1.

  The polypropylene resin composition is put into an extruder having a screw diameter of 40 mm, extruded from a T-die at a resin temperature of 230 ° C., sandwiched between mirror-finished metal cast rolls having a surface temperature of 80 ° C., and cooled and solidified. A polypropylene resin sheet (thermoforming sheet) having a width of 500 mm and a thickness of 3.2 mm was obtained continuously at a speed of 0.5 m / min.

  The above-described various evaluations were performed on this sheet. It was confirmed that this sheet had a good drawdown resistance, an excellent spreadability, and a molded product with little uneven thickness, and the molded product had sufficient buckling properties. The composition and evaluation results of the thermoforming sheet are summarized in Table 3.

Example 2
The resin to be used is 50% by weight of WAYMAXMFX8 manufactured by Nippon Polypro Co., Ltd. as polypropylene resin (X), and Novatec EC9 manufactured by Nippon Polypro Co., Ltd. as polypropylene resin (Y) ("Y1" in Tables 2, 3 and 4). A polypropylene resin sheet was obtained and evaluated in the same manner as in Example 1 except that a polypropylene resin composition was prepared by uniformly stirring and mixing a mixture composed of 50% by weight with a ribbon blender. The properties of the polypropylene resin Y1 were measured by the evaluation method described above and are shown in Table 2. It was confirmed that this sheet had a good drawdown resistance, an excellent spreadability, and a molded product with little uneven thickness, and the molded product had sufficient buckling properties. The composition and evaluation results of the thermoforming sheet are summarized in Table 3.

Example 3
A polypropylene resin sheet was obtained and evaluated in the same manner as in Example 2 except that the polypropylene resin (X) was 20% by weight and the polypropylene resin (Y) was 80% by weight. It was confirmed that this sheet had a good drawdown resistance, an excellent spreadability, and a molded product with little uneven thickness, and the molded product had sufficient buckling properties. The composition and evaluation results of the thermoforming sheet are summarized in Table 3.

Example 4
A polypropylene resin sheet was obtained and evaluated in the same manner as in Example 2 except that the polypropylene resin (X) was 10 wt% and the polypropylene resin (Y) was 90 wt%. It was confirmed that this sheet had a good drawdown resistance, an excellent spreadability, and a molded product with little uneven thickness, and the molded product had sufficient buckling properties. The composition and evaluation results of the thermoforming sheet are summarized in Table 3.

Example 5
As polypropylene resin (X), a polypropylene resin sheet was obtained and evaluated in the same manner as in Example 3 except that WAYMAX manufactured by Nippon Polypro Co., Ltd. (indicated as “X2” in Tables 1 and 3) was used. It was. The properties of the polypropylene resin X2 were measured by the evaluation method described above and are shown in Table 1. It was confirmed that this sheet had a good drawdown resistance, an excellent spreadability, and a molded product with little uneven thickness, and the molded product had sufficient buckling properties. The composition and evaluation results of the thermoforming sheet are summarized in Table 3.

Example 6
As a polypropylene resin (X), a polypropylene resin sheet was obtained and evaluated in the same manner as in Example 3 except that WAYMAX MFX6 manufactured by Nippon Polypro Co., Ltd. (referred to as “X3” in Tables 1 and 3) was used. went. The properties of the polypropylene resin X3 were measured by the above-described evaluation method and are shown in Table 1. It was confirmed that this sheet had a good drawdown resistance, an excellent spreadability, and a molded product with little uneven thickness, and the molded product had sufficient buckling properties. The composition and evaluation results of the thermoforming sheet are summarized in Table 3.

Example 7
As a polypropylene resin (X), a polypropylene resin sheet was obtained and evaluated in the same manner as in Example 3 except that WAYMAX MFX3 manufactured by Nippon Polypro Co., Ltd. (referred to as “X4” in Tables 1 and 3) was used. went. The properties of the polypropylene resin X4 were measured by the evaluation method described above and are shown in Table 1. It was confirmed that this sheet had a good drawdown resistance, an excellent spreadability, and a molded product with little uneven thickness, and the molded product had sufficient buckling properties. The composition and evaluation results of the thermoforming sheet are summarized in Table 3.

Example 8
A polypropylene resin sheet was obtained and evaluated in the same manner as in Example 3 except that Daploy WB140HMS (denoted as “X5” in Tables 1 and 3) manufactured by Borealis AG was used as the polypropylene resin (X). The properties of the polypropylene resin X5 were measured by the evaluation method described above and are shown in Table 1. This sheet was slightly good in draw-down resistance, excellent in spreadability, and obtained a molded product with little uneven thickness. It was confirmed that the molded product had sufficient buckling properties. The composition and evaluation results of the thermoforming sheet are summarized in Table 3.

Example 9
As a polypropylene resin (Y), a polypropylene resin sheet was obtained in the same manner as in Example 3 except that Novatec EA9 (referred to as “Y2” in Tables 2, 3 and 4) manufactured by Nippon Polypro Co., Ltd. was used. Evaluation was performed. The properties of the polypropylene resin Y2 were measured by the evaluation method described above and are shown in Table 2. It was confirmed that this sheet had a good drawdown resistance, an excellent spreadability, and a molded product with little uneven thickness, and the molded product had sufficient buckling properties. The composition and evaluation results of the thermoforming sheet are summarized in Table 3.

Comparative Example 1
A polypropylene resin sheet was obtained and evaluated in the same manner as in Example 1 except that the polypropylene resin composition used was Novatec EC9 manufactured by Nippon Polypro Co., Ltd. It was confirmed that this sheet had poor drawdown resistance, poor spreadability, and a molded article having a large uneven thickness, and the molded article had low buckling strength. The results are summarized in Table 4.

Comparative Example 2
A polypropylene resin sheet was obtained and evaluated in the same manner as in Example 1 except that the polypropylene resin composition used was Novatec EA9 manufactured by Nippon Polypro Co., Ltd. It was confirmed that this sheet had poor drawdown resistance, poor spreadability, and a molded article having a large uneven thickness, and the molded article had low buckling strength. The results are summarized in Table 4.

Comparative Example 3
A polypropylene resin sheet was obtained and evaluated in the same manner as in Example 2 except that a polypropylene resin composition containing 3% by weight of polypropylene resin (X) and 97% by weight of polypropylene resin (Y) was used. It was confirmed that this sheet had poor drawdown resistance, poor spreadability, and a molded article having a large uneven thickness, and the molded article had low buckling strength. The results are summarized in Table 4.

Claims (3)

A sheet for thermoforming having a thickness of 1 mm or more formed of a polypropylene resin composition, wherein the polypropylene resin composition has a polypropylene resin (X) of 5 to 100% by weight and a polypropylene resin (Y) having a long-chain branched structure. 95 to 0% by weight, the polypropylene resin (X) has the following characteristics (X-i) and (X-ii), and the polypropylene resin (Y) has the following characteristics (Y-i), ( A sheet for thermoforming characterized by having Y-ii).
Characteristic (X-i): Melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kg is 0.1 to 30 g / 10 minutes Characteristic (X-ii): Melt tension (MT) (unit: g) Characteristic (Yi) satisfying log (MT) ≧ −0.9 × log (MFR) +0.7 or log (MT) ≧ 1.15: Melt flow measured at 230 ° C. and 2.16 kg load Rate (MFR) is 0.1 to 9.5 g / 10 min Characteristic (Y-ii): Melt tension (MT) (unit: g) is log (MT) <− 0.9 × log (MFR) +0.7 And log (MT) <1.15 The sheet for thermoforming according to claim 1, wherein the polypropylene resin (X) having the long-chain branched structure has the following characteristics (X-iii).
Characteristic (X-iii): mm fraction of propylene unit 3 chain by ¹³ C-NMR is 95% or more   A molded body obtained by thermoforming the thermoforming sheet according to claim 1 or 2.